JP2024146770A - Optical laminate and method for producing same - Google Patents

Abstract

[Problem] To provide an optical laminate capable of suppressing scratches occurring in a liquid crystal retardation layer. [Solution] The optical laminate comprises a pressure-sensitive adhesive layer and a first liquid crystal retardation layer with a substrate. The pressure-sensitive adhesive layer is a cured layer of a photocurable pressure-sensitive adhesive composition. The first liquid crystal retardation layer with a substrate comprises, in order from the pressure-sensitive adhesive layer side, a first liquid crystal retardation layer and a first substrate layer. The first liquid crystal retardation layer has a first polymer layer containing a polymer of a polymerizable liquid crystal compound. The first substrate layer is peelable from the first liquid crystal retardation layer. The first liquid crystal retardation layer with the substrate has a light transmittance Tx of 20% or more at a wavelength of 317 nm. [Selected Figure] Figure 1

Description

The present invention relates to an optical laminate and a method for producing the same.

A circular polarizing plate containing a polarizing element and a retardation element is known as an optical laminate having anti-reflection properties. As the retardation element of the circular polarizing plate, a liquid crystal retardation layer having a polymer layer which is a layer of a polymer of a polymerizable liquid crystal compound may be used. The polymer layer of the liquid crystal retardation layer can be obtained by forming a coating layer by applying a composition containing a polymerizable liquid crystal compound onto a substrate layer or an alignment layer formed on the substrate layer, and irradiating the coating layer with active energy rays to polymerize the polymerizable liquid crystal compound (for example, Patent Document 1). The liquid crystal retardation layer is attached to an optical film constituting an optical laminate such as a polarizing plate or another liquid crystal retardation layer while being supported by the substrate layer, and then the substrate layer is peeled off and removed.

JP 2020-52365 A

In order to meet the demand for thinner optical laminates applied to displays such as organic EL displays, a photocurable adhesive may be used to bond the layers of the optical laminate. For example, when a liquid crystal retardation layer and an optical film supported on a base layer are laminated via a photocurable adhesive, the photocurable adhesive may be cured by irradiating light from the base layer side, and then the base layer may be peeled off to produce an optical laminate. The optical laminate is usually produced while transporting the liquid crystal retardation layer and the optical film supported on the base layer, and the laminate obtained by peeling off the base layer is also transported and subjected to product processing. During such product processing, scratches may occur on the liquid crystal retardation layer exposed by peeling off the base layer.

The present invention aims to provide an optical laminate that includes a pressure-sensitive adhesive layer, which is a cured layer of a photocurable pressure-sensitive adhesive composition, and a liquid crystal retardation layer, and that can suppress scratches that occur in the liquid crystal retardation layer, and a method for producing the same.

The present invention provides the following optical laminate and a method for producing the same.
[1] An optical laminate comprising an adhesive layer and a first liquid crystal retardation layer with a substrate,
the pressure-sensitive adhesive layer is a cured product layer of a photocurable pressure-sensitive adhesive composition,
The first liquid crystal retardation layer with substrate includes, in order from the pressure-sensitive adhesive layer side, a first liquid crystal retardation layer and a first substrate layer,
The first liquid crystal retardation layer has a first polymer layer containing a polymer of a polymerizable liquid crystal compound,
the first base layer is peelable from the first liquid crystal retardation layer,
The optical laminate, wherein the first liquid crystal retardation layer with the substrate has a light transmittance Tx of 20% or more at a wavelength of 317 nm.
[2] The optical laminate according to [1], wherein the light transmittance Ts of the first base layer at a wavelength of 317 nm is 20% or more.
[3] The first base layer is a film base,
The optical laminate according to [1] or [2], wherein the resin constituting the film substrate is triacetyl cellulose.
[4] The optical laminate according to any one of [1] to [3], wherein the first base layer has a thickness of 40 μm or less.
[5] The optical laminate according to any one of [1] to [4], wherein the first liquid crystal retardation layer has a positive wavelength dispersion.
[6] The optical laminate according to any one of [1] to [5], wherein the first liquid crystal retardation layer is the first polymer layer.
[7] The pressure-sensitive adhesive composition contains a photopolymerization initiator,
The optical laminate according to any one of [1] to [6], wherein the residual amount of the photopolymerization initiator in the adhesive layer is 0.050 mass% or less.
[8] The optical laminate according to any one of [1] to [7], wherein the pressure-sensitive adhesive layer has a thickness of 2 μm or more.
[9] The pressure-sensitive adhesive composition contains a photopolymerization initiator,
The optical laminate according to any one of [1] to [8], wherein the photopolymerization initiator has a maximum absorption wavelength in the wavelength range of 280 nm or more and 340 nm or less.
[10] The optical laminate according to any one of [1] to [9], further comprising an optical film on the opposite side of the pressure-sensitive adhesive layer to the first liquid crystal retardation layer.
[11] The optical film includes at least one of a polarizing plate including a polarizing element and a second liquid crystal retardation layer,
The optical laminate according to [10], wherein the second liquid crystal retardation layer has a second polymer layer containing a polymer of a polymerizable liquid crystal compound.
[12] The optical laminate according to [10] or [11], wherein the light transmittance Ty of the optical film is equal to or smaller than the light transmittance Tx of the first liquid crystal retardation layer with the substrate.
[13] A method for producing an optical laminate according to any one of [1] to [12],
A step (S1) of forming a coating layer of the pressure-sensitive adhesive composition on the first liquid crystal retardation layer side of the first liquid crystal retardation layer with a substrate;
and (S2) forming the pressure-sensitive adhesive layer by irradiating the coating layer formed in the step (S1) with light through the substrate-attached first liquid crystal retardation layer.
[14] The light is ultraviolet light,
The method for producing an optical laminate according to [13], wherein an integrated light amount of the light irradiated to the coating layer in the step (S2) is 10 mJ/cm ² or more and 1000 mJ/cm ² or less.

The present invention provides an optical laminate that can suppress scratches that occur in the liquid crystal retardation layer.

FIG. 1 is a cross-sectional view that illustrates an optical laminate according to one embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating an optical laminate according to another embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating an optical laminate according to still another embodiment of the present invention.

Below, preferred embodiments of the optical laminate and the method for manufacturing the optical laminate will be described with reference to the drawings.

<Optical laminate>
1 to 3 are cross-sectional views each showing a schematic diagram of an optical laminate according to an embodiment of the present invention. As shown in Fig. 1 to 3, the optical laminates 1 to 3 include a first adhesive layer 31 (adhesive layer) and a substrate-attached first liquid crystal retardation layer 13. The first adhesive layer 31 is a cured layer of a photocurable adhesive composition.

The first liquid crystal retardation layer 13 with substrate comprises, in order from the first adhesive layer 31 side, a first liquid crystal retardation layer 11 and a first substrate layer 16. In the optical laminates 1 to 3, it is preferable that the first adhesive layer 31 and the first liquid crystal retardation layer 11 are in direct contact. In the first liquid crystal retardation layer 13 with substrate, it is preferable that the first liquid crystal retardation layer 11 and the first substrate layer 16 are in direct contact.

The first liquid crystal retardation layer 11 has a first polymer layer containing a polymer of a polymerizable liquid crystal compound. The first liquid crystal retardation layer 11 is a first polymer layer, or a multilayer body of a first polymer layer and a first alignment layer. The first base layer 16 is peelable from the first liquid crystal retardation layer 11. When the first liquid crystal retardation layer is a multilayer body, the first alignment layer is disposed on the first base layer 16 side, and the first polymer layer is disposed on the first adhesive layer 31 side.

The optical laminates 1 to 3 usually have a layer on the side of the first adhesive layer 31 opposite to the first liquid crystal retardation layer 11, and this layer may be an optical film 20. When the optical laminates 1 to 3 include the optical film 20, it is preferable that the optical film 20 and the first adhesive layer 31 are in direct contact.

In the optical laminates 1 to 3, the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 at a wavelength of 317 nm is 20% or more. The light transmittance Tx is preferably 25% or more, more preferably 30% or more, may be 40% or more, may be 50% or more, and is usually 90% or less. The light transmittance Tx can be measured by the method described in the examples below.

As described later, the optical laminates 1 to 3 can be manufactured by laminating the first liquid crystal retardation layer 11 side of the substrate-attached first liquid crystal retardation layer 13 and a layer such as the optical film 20 via a coating layer of a photocurable adhesive composition, and curing the adhesive composition by irradiating light from the substrate-attached first liquid crystal retardation layer 13 side. When the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 is within the above range, the irradiated light easily passes through the substrate-attached first liquid crystal retardation layer 13 and easily reaches the coating layer of the adhesive composition, so that the reaction of the adhesive composition proceeds sufficiently, and a hard first adhesive layer 31 is easily obtained.

After the first adhesive layer 31 is formed and the first base layer 16 is peeled off, the optical laminates 1 to 3 are further transported and subjected to product processing and the like. During such product processing, if a transport roll or the like comes into contact with the surface of the first liquid crystal retardation layer 11 exposed by the peeling off of the first base layer 16, scratches may occur. Since the optical laminates 1 to 3 have the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 within the above-mentioned range, a hard first adhesive layer 31 in which the adhesive composition is sufficiently cured can be obtained. The first liquid crystal retardation layer 11 on the relatively hard first adhesive layer 31 is less likely to be scratched by contact with a transport roll or the like compared to the first liquid crystal retardation layer on the relatively soft first adhesive layer. Therefore, the optical laminates 1 to 3 can suppress scratches occurring in the first liquid crystal retardation layer 11.

Since the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 is within the above range, when the adhesive composition is irradiated with light through the substrate-attached first liquid crystal retardation layer 13, the adhesive composition can be sufficiently cured even if the cumulative amount of irradiated light is reduced. This makes it possible to suppress the heat generated by light irradiation, and therefore the occurrence of thermal wrinkles in which the substrate-attached first liquid crystal retardation layer 13 is deformed can also be suppressed. Thermal wrinkles are a phenomenon in which the flatness of layers such as films constituting an optical laminate is impaired due to the influence of heat generated from a light source for light irradiation and the curing shrinkage of the adhesive composition due to light irradiation, and refer to deformation that occurs in a galvanized iron shape along the conveying direction (flow direction) during the manufacture of the optical laminate. When deformation occurs, peelable layers such as the first substrate layer may cause tunneling during the conveying of the layers constituting the optical laminate. If the deformation is maintained even after the substrate-attached first liquid crystal retardation layer 13 is bonded to a polarizing plate or the like, it is not preferable because unevenness is visible in reflected light or unevenness is visible in transmitted light. In particular, when the thickness of the adhesive layer is 1.0 μm or more, or when the thickness of the first base layer on the light irradiation side is 60 μm or less, the first base layer is easily deformed by heat.

On the other hand, when the light transmittance Tx of the first liquid crystal retardation layer 13 with the substrate falls below the above range, the irradiated light does not easily pass through the first liquid crystal retardation layer 13 with the substrate, and the light does not easily reach the coating layer of the adhesive composition, so the reaction of the adhesive composition does not easily proceed. The first adhesive layer, in which the reaction of the adhesive composition does not proceed sufficiently and is insufficiently cured, becomes soft. The first liquid crystal retardation layer on the soft first adhesive layer is easily scratched when it comes into contact with a transport roll or the like. In addition, if the cumulative light amount of the irradiated light is increased to sufficiently react the adhesive composition, the curing shrinkage accompanying the reaction of the adhesive composition increases, and heat wrinkles that deform the first liquid crystal retardation layer with the substrate are likely to occur.

The optical laminates 1 to 3 can be used in display devices and the like, which will be described later. When the optical laminates 1 to 3 include the optical film 20, a laminate with the optical film (described later) obtained by peeling off and removing the first base layer 16 can be applied to display devices and the like. The optical laminates 1 to 3 and the laminate with the optical film, which include the optical film 20, may be retardation bodies including a first liquid crystal retardation layer 11 and a second liquid crystal retardation layer 21. The optical laminates 1 to 3 and the laminate with the optical film may include a polarizing element or a polarizing plate 50 and a first liquid crystal retardation layer 11 (FIG. 1), or may include a polarizing element or a polarizing plate 50, a first liquid crystal retardation layer 11, and a second liquid crystal retardation layer 21 (FIG. 2). Such optical laminates 1 to 3 and the laminate with the optical film may have an anti-reflection function and function as a circular polarizing plate.

(First adhesive layer)
As described above, the first adhesive layer 31 is a cured layer of the photocurable adhesive composition. The photocurable adhesive composition usually contains a curable (polymerizable) compound, and preferably contains a photopolymerization initiator (described later).

The remaining amount of the photopolymerization initiator in the first adhesive layer 31 is preferably 0.050% by mass or less, may be 0.030% by mass or less, may be 0.020% by mass or less, more preferably 0.015% by mass or less, may be 0.010% by mass or less, and even more preferably 0.005% by mass or less, and is usually 0% by mass or more, may be 0.0001% by mass or more. It is considered that the reaction of the adhesive composition proceeds sufficiently and a hard first adhesive layer 31 is formed by providing the first adhesive layer 31 in which the remaining amount of the photopolymerization initiator is within the above range, and therefore, scratches occurring on the surface of the first liquid crystal retardation layer 11 can be further suppressed.

The photopolymerization initiator contained in the adhesive composition preferably has a maximum absorption wavelength in the wavelength range of 280 nm to 340 nm. The maximum absorption wavelength of the photopolymerization initiator may be in the wavelength range of 280 nm to 330 nm, or in the wavelength range of 300 nm to 320 nm. By using a photopolymerization initiator having a maximum absorption wavelength in this range, the adhesive composition is easily reacted with light that has passed through the substrate-attached first liquid crystal retardation layer 13 having the above-mentioned light transmittance Tx. This makes it possible to provide optical laminates 1 to 3 that can further suppress scratches that occur on the surface of the first liquid crystal retardation layer 11.

The photopolymerization initiator preferably contains at least one of a photocationic polymerization initiator and a photoradical polymerization initiator, which will be described later. The content of the photopolymerization initiator in the adhesive composition may be 0.1 parts by mass or more and 10 parts by mass or less, or 1 part by mass or more and 8 parts by mass or less, relative to 100 parts by weight of the curable compound.

The thickness of the first adhesive layer 31 is preferably 2.0 μm or more, more preferably 2.5 μm or more, and may be 3.0 μm or more. By providing a first adhesive layer 31 with a large thickness, scratches occurring on the surface of the first liquid crystal retardation layer 11 can be further suppressed. A more detailed description of the first adhesive layer and the adhesive composition will be given later.

(First Liquid Crystal Retardation Layer with Substrate)
The first liquid crystal retardation layer with a substrate has a first liquid crystal retardation layer 11 on a first substrate layer 16. The first liquid crystal retardation layer with a substrate can be obtained by applying a composition for forming a first liquid crystal retardation layer containing a polymerizable liquid crystal compound onto the first substrate layer 16 or onto a first alignment layer 17 formed on the first substrate layer 16, and polymerizing the polymerizable liquid crystal compound in the applied layer. A detailed description of the method for producing the first liquid crystal retardation layer will be given later.

(First liquid crystal retardation layer)
The first liquid crystal retardation layer 11 includes the first polymer layer as described above, and may further include a first alignment layer. The polymer included in the first polymer layer is usually a polymerizable liquid crystal compound. The first polymer layer is formed from a first liquid crystal retardation layer forming composition containing a polymerizable liquid crystal compound as described later. The first polymer layer is When the first liquid crystal retardation layer 11 includes a first alignment layer, the first polymer layer and the first alignment layer are usually in direct contact with each other. The layer is disposed on the first substrate layer 16 side of the first polymer layer.

The first liquid crystal retardation layer 11 is preferably a first polymer layer. This makes it possible to further suppress scratches on the surface of the first liquid crystal retardation layer 11 exposed by peeling off the first base layer 16 from the optical laminates 1 to 3.

The first liquid crystal retardation layer 11 preferably has positive wavelength dispersion from the viewpoint of sufficiently curing the adhesive composition when irradiated with light from the substrate-attached first liquid crystal retardation layer 13 side. This can further suppress scratches on the surface of the first liquid crystal retardation layer 11 exposed by peeling the first substrate layer 16 from the optical laminates 1 to 3. It can also improve the adhesion between the first liquid crystal retardation layer 11 and the optical film 20. A more detailed description of the first liquid crystal retardation layer 11 will be given later.

(First Base Layer)
The first base layer 16 supports the first liquid crystal retardation layer 11. The first base layer 16 is peelable from the first liquid crystal retardation layer 11. The light transmittance Ts of the first base layer 16 at a wavelength of 317 nm is preferably 20% or more, more preferably 25% or more, and may be 30% or more. When the light transmittance Ts of the first base layer 16 is within the above-mentioned range, it is easy to adjust the light transmittance Tx of the first liquid crystal retardation layer 13 with the substrate to the above-mentioned range. When the light transmittance Ts of the first base layer 16 is within the above-mentioned range, the first base layer 16 does not contain an ultraviolet absorber and is considered to have excellent ultraviolet transmittance. The light transmittance Ts of the first base layer 16 can be measured by the same method as the measurement method of the light transmittance Tx of the first liquid crystal retardation layer 13 with the substrate described in the examples described later.

The first substrate layer 16 is preferably a film substrate. The resin constituting the film substrate is preferably triacetyl cellulose. This makes it easier to adjust the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 to the above-mentioned range.

The thickness of the first substrate layer 16 is preferably 40 μm or less, may be 35 μm or less, may be 30 μm or less, and is usually 10 μm or more. The thickness of the first substrate layer 16 is preferably 30 μm or more and 40 μm or less. By having the thickness of the first substrate layer 16 within the above range, it becomes easier to adjust the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 to the above range while maintaining good handleability of the substrate-attached first liquid crystal retardation layer 13. A more detailed description of the first substrate layer 16 will be given later.

(Optical film)
Examples of the optical film 20 include a polarizing element, a polarizing plate 50 including a polarizing element, a second liquid crystal retardation layer 21, or a combination thereof. The optical film 20 preferably includes at least one of the polarizing plate 50 and the second liquid crystal retardation layer 21 (FIGS. 1 and 2), and may include both the polarizing plate 50 and the second liquid crystal retardation layer 21 (FIG. 3). In the case of including such an optical film 20, it is preferable to set the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 to the above-mentioned range in order to obtain the optical laminates 1 to 3 that can suppress scratches occurring on the surface of the first liquid crystal retardation layer 13.

The optical film 20 may be a second liquid crystal retardation layer 23 with a substrate (FIG. 2). The second liquid crystal retardation layer 23 with a substrate has a second substrate layer 26 and a second liquid crystal retardation layer 21. In the second liquid crystal retardation layer 23 with a substrate, the second liquid crystal retardation layer 21 and the second substrate layer 26 are preferably in direct contact with each other, and the second substrate layer 26 may be peelable from the second liquid crystal retardation layer 21. When the optical film 20 is the second liquid crystal retardation layer 23 with a substrate, the optical laminate 2 usually has, in order from the first adhesive layer 31 side, the second liquid crystal retardation layer 21 and the second substrate layer 26.

The second liquid crystal retardation layer 21 has a second polymer layer containing a polymer of a polymerizable liquid crystal compound. The second liquid crystal retardation layer 21 is a second polymer layer, or a multilayer body of the second polymer layer and the second alignment layer. The polymer contained in the second polymer layer is usually a polymer polymerized in an aligned state of the polymerizable liquid crystal compound. The second polymer layer is formed from a second liquid crystal retardation layer forming composition containing a polymerizable liquid crystal compound, as described later. The second polymer layer can be a layer that exhibits a phase difference. When the second liquid crystal retardation layer 21 includes a second alignment layer, the second polymer layer and the second alignment layer are usually in direct contact with each other. As shown in FIG. 2, when the optical film 20 has the second liquid crystal retardation layer 21 and the second base layer 26, it is preferable that the second alignment layer is arranged such that the second polymer layer is disposed on the first adhesive layer 31 side and the second alignment layer is disposed on the second base layer 26 side. As described below, when the optical laminate 2 shown in FIG. 2 is used to produce the optical laminate 3 (FIG. 3), the second liquid crystal retardation layer 21 preferably has positive wavelength dispersion from the viewpoint of sufficiently curing the adhesive composition interposed between the second liquid crystal retardation layer 21 and the polarizing plate 50 as described below.

As shown in FIG. 3, the optical film 20 may have the second liquid crystal retardation layer 21 and the polarizing plate 50 in order from the first adhesive layer 31 side. The second liquid crystal retardation layer 21 and the polarizing plate 50 may be laminated via the second adhesive layer 32. In this case, it is preferable that the second liquid crystal retardation layer 21 and the second adhesive layer 32 are in direct contact, and it is preferable that the second adhesive layer 32 and the polarizing plate 50 are in direct contact. In the optical laminate 3 shown in FIG. 3, the second liquid crystal retardation layer 21 may have a positive wavelength dispersion. As will be described later, when forming the second adhesive layer 32 between the second liquid crystal retardation layer 21 and the polarizing plate 50, when the adhesive composition interposed between the second liquid crystal retardation layer 21 and the polarizing plate 50 is cured by irradiating light through the first liquid crystal retardation layer 13 side with the substrate, it is preferable that the second liquid crystal retardation layer 21 has a positive wavelength dispersion from the viewpoint of sufficiently curing the adhesive composition. This can further reduce the occurrence of scratches on the surface of the first liquid crystal retardation layer 11 exposed by peeling off the first base layer 16 from the optical laminate 3. It can also improve the adhesion between the second liquid crystal retardation layer 21 and the polarizing plate 50.

The light transmittance Ty of the optical film 20 is preferably equal to or smaller than the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13. When such an optical film 20 is provided, setting the light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 within the above range is suitable for obtaining optical laminates 1 to 3 that can suppress scratches on the surface of the first liquid crystal retardation layer 13. The light transmittance Ty of the optical film 20 can be measured by the method described in the examples below, and is the light transmittance at a wavelength of 317 nm. A more detailed description of the optical film 20, the polarizing plate 50, and the second liquid crystal retardation layer 21 will be given later.

In the optical laminate 3 (FIG. 3), the light transmittance at a wavelength of 317 nm of the laminated portion (hereinafter also referred to as "retardation body R") in which the substrate-attached first liquid crystal retardation layer 13, the first adhesive layer 31, and the second liquid crystal retardation layer 21 are laminated in this order is preferably 3% or more, may be 5% or more, may be 10% or more, and is usually 30% or less. The light transmittance of the retardation body R can be measured by the method described in the light transmittances Tx and Ty in the examples described later.

When the second adhesive layer 32 of the optical laminate 3 is a cured product of an adhesive composition containing a photopolymerization initiator, the remaining amount of the photopolymerization initiator in the second adhesive layer 32 may be, for example, 0.10% by mass or less, 0.080% by mass or less, 0.050% by mass or less, 0.030% by mass or less, 0.010% by mass or less, or 0.005% by mass or less, and is usually 0% by mass or more, and may be 0.001% by mass or more. The remaining amount of the photopolymerization initiator in the second adhesive layer 32 may be greater than the remaining amount of the photopolymerization initiator in the first adhesive layer 31.

(Laminate with optical film)
The laminate with the optical film usually includes the optical film 20, the first adhesive layer 31, and the first liquid crystal retardation layer 11 in this order. When the optical film 20 includes the polarizing plate 50 or the second liquid crystal retardation layer 21, the laminate with the optical film may include the polarizing plate 50, the first adhesive layer 31, and the first liquid crystal retardation layer 11 in this order, or may include the second base layer 26, the second liquid crystal retardation layer 21, the first adhesive layer 31, and the first liquid crystal retardation layer 11 in this order. When the optical film 20 includes the polarizing plate 50 and the second liquid crystal retardation layer 21, the laminate with the optical film may include the polarizing plate 50, the second adhesive layer 32, the second liquid crystal retardation layer 21, the first adhesive layer 31, and the first liquid crystal retardation layer 11 in this order.

<Method of manufacturing optical laminate>
The method for producing the optical laminates 1 to 3 includes the steps of:
A step (S1) of forming a first coating layer (coating layer) of a pressure-sensitive adhesive composition on the first liquid crystal retardation layer 11 side of the substrate-attached first liquid crystal retardation layer 13;
and a step (S2) of forming a first adhesive layer 31 by irradiating the first coating layer formed in the step (S1) with light through the substrate-attached first liquid crystal retardation layer 13 .

The light transmittance Tx of the substrate-attached first liquid crystal retardation layer 13 is 20% or more as described above. Therefore, even when the first coating layer on the substrate-attached first liquid crystal retardation layer 13 is irradiated with light through the substrate-attached first liquid crystal retardation layer 13, the first adhesive layer 31 in which the adhesive composition is sufficiently cured can be obtained. When the adhesive composition contains a photopolymerization initiator, the amount of the photopolymerization initiator remaining in the first adhesive layer 31 can also be reduced.

The light irradiated in step (S2) is preferably ultraviolet light. Since the ultraviolet transmittance of the substrate-attached first liquid crystal retardation layer 13 is high, the integrated light amount of the light irradiated to the first coating layer in step (S2) can be reduced. The integrated light amount of the light irradiated to the first coating layer in step (S2) is, for example, 10 mJ/cm ² or more and 1000 mJ/cm ² or less, but may be a smaller integrated light amount within this range, preferably 10 mJ/cm ² or more and 300 mJ/cm ² or less, 30 mJ/cm ² or more and 200 mJ/cm ² or less, and more preferably 50 mJ/cm ² or more and 125 mJ/cm ² or less. In the manufacturing method of the optical laminates 1 to 3, even if the integrated light amount of the irradiated light is small, the adhesive composition can be sufficiently cured. Therefore, it is possible to suppress the occurrence of thermal wrinkles in which the substrate-attached first liquid crystal retardation layer 13 is deformed due to the influence of heat generated by irradiation with light such as ultraviolet rays (heat generated from a lamp, etc.) and curing shrinkage of the adhesive composition due to irradiation with light, while also suppressing the occurrence of scratches on the first liquid crystal retardation layer 11 during product processing, etc.

On the side opposite to the first liquid crystal retardation layer 11 of the first coating layer, a layer to be bonded to the first liquid crystal retardation layer 11 using a pressure-sensitive adhesive composition such as an optical film is usually laminated. When the layer is an optical film 20, the first coating layer of the pressure-sensitive adhesive composition may be formed between the optical film 20 and the first liquid crystal retardation layer 11. The first coating layer may be formed on the first liquid crystal retardation layer 13 with the substrate and the optical film 20 may be laminated thereon, the first coating layer may be formed on the optical film 20 and the first liquid crystal retardation layer 13 with the substrate may be laminated thereon, or the first coating layer may be formed on both the first liquid crystal retardation layer 13 with the substrate and the optical film 20 and the two may be laminated thereon.

Since the conventional first liquid crystal retardation layer with a substrate has a small light transmittance, it is difficult to obtain an adhesive layer in which the active energy ray curable adhesive composition or the photocurable adhesive composition is sufficiently cured by irradiating light through the first liquid crystal retardation layer with a substrate. Therefore, due to the polymerization initiator remaining in the adhesive layer, problems such as a decrease in optical properties may occur when a durability test or the like is performed. In contrast, since the first liquid crystal retardation layer with a substrate of this embodiment has a large light transmittance, a first adhesive layer in which the above-mentioned adhesive composition is sufficiently cured can be obtained by irradiating light through the first liquid crystal retardation layer with a substrate. In addition, even when a retardation body (retardation body R) including the first liquid crystal retardation layer and the second liquid crystal retardation layer is formed using the first liquid crystal retardation layer with a substrate, the light transmittance of the retardation body R can also be increased. Therefore, even when a photocurable adhesive composition, such as an active energy ray curable adhesive composition or a photocurable adhesive composition, is used to bond the retardation body R to a polarizing element, a sufficiently cured second adhesive layer is easily formed. This makes it possible to reduce the thickness of the optical laminate including the first liquid crystal retardation layer, the second liquid crystal retardation layer, and the polarizing element, and also improves foldability, suppresses curling, and improves durability due to improved barrier properties provided by the first adhesive layer and the second adhesive layer.

The optical laminate 3 shown in Fig. 3 may be obtained by bonding the retarder R and the polarizing element as described above. In this case, the retarder R may be the optical laminate 2 shown in Fig. 2 from which the second base layer has been peeled off. The method for producing the optical laminate 3 may include, for example,
A step (S11) of preparing an optical laminate 2;
a step (S12) of peeling off the second base layer 26 from the optical laminate 2 to obtain a retardation body R in which the base-attached first liquid crystal retardation layer 13, the first adhesive layer 31, and the second liquid crystal retardation layer 21 are laminated in this order;
a step (S13) of laminating the second liquid crystal retardation layer 21 side of the retarder R and a polarizing element via a second coating layer of the adhesive composition;
The method may further include a step (S14) of irradiating the second coating layer formed in the step (13) with light through a retardation body R to form a second adhesive layer 32.

Step (S11) may be a step of preparing the optical laminate 2 by the above-mentioned steps (S1) and (S2). When peeling off the second substrate layer 26 in step (S12), only the second substrate layer 26 may be peeled off, or the second alignment layer may be peeled off together with the second substrate layer 26.

In step (S13), the second coating layer of the adhesive composition may be formed on the second liquid crystal retardation layer 21 of the retardation body R, on the polarizing element, or on both of them.

The light irradiated in step (S14) is preferably ultraviolet light. As described above, since the light transmittance of the retarder R is large, even if the second coating layer is irradiated with light from the retarder R side, the second adhesive layer 32 in which the adhesive composition is sufficiently cured can be obtained. In addition, the integrated light amount of the light irradiated to the second coating layer in step (S14) can be reduced. When the adhesive composition contains a photopolymerization initiator, the remaining amount of the photopolymerization initiator in the second adhesive layer 32 can also be reduced. The integrated light amount of the light irradiated to the second coating layer in step (S14) can be the integrated light amount described in step (S2) above.

<Method of manufacturing laminate with optical film>
The method for producing a laminate with an optical film includes a step of peeling off the first base layer 16 from the optical laminates 1 to 3 including the optical film 20. When peeling off the first base layer 16, only the first base layer 16 may be peeled off, or the first alignment layer may be peeled off together with the first base layer 16.

<Display Device>
The optical laminates 1 to 3 can be applied to a display device by peeling off the first base layer 16. The display device can include a laminate with an optical film and an image display element (such as an organic EL display element). The laminate with the optical film is disposed on the viewing side of the image display element. The laminate with the optical film can be attached to the image display element using a pressure-sensitive adhesive layer.

The display device is not particularly limited, and examples include organic electroluminescence (organic EL) display devices, inorganic electroluminescence (inorganic EL) display devices, liquid crystal display devices, and electroluminescence display devices.

The display device can be used as mobile devices such as smartphones and tablets, televisions, digital photo frames, electronic signs, measuring instruments, gauges, office equipment, medical equipment, computing equipment, etc.

Hereinafter, details of each layer constituting the optical laminate and a method for producing each layer will be described.
<Adhesive layer (first adhesive layer, second adhesive layer)>
The first adhesive layer is preferably used when bonding the optical film and the first liquid crystal retardation layer. The second adhesive layer is preferably used when bonding members constituting the optical film (e.g., a polarizing plate and a second liquid crystal retardation layer). The first adhesive layer for bonding the first liquid crystal retardation layer and the second liquid crystal retardation layer is preferably an adhesive layer described later.

The adhesive layer (the first adhesive layer or the second adhesive layer) is a pressure-sensitive adhesive layer or an adhesive layer, and can be formed from a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition is a pressure-sensitive adhesive composition or an adhesive composition.

(Adhesive Layer)
The adhesive layer exerts adhesiveness by attaching itself to an adherend, and is called a pressure-sensitive adhesive. As the adhesive composition forming the adhesive layer, a conventionally known adhesive composition having excellent optical transparency can be used without any particular limitation, and for example, an adhesive composition having a base polymer such as an acrylic resin, a urethane resin, a silicone resin, or a polyvinyl ether resin can be used. In addition, it may be an active energy ray curable adhesive composition, a heat curable adhesive composition, etc. Among these, an adhesive composition having an acrylic resin as a base polymer, which is excellent in transparency, adhesion, removability, weather resistance, heat resistance, etc., is preferable.
The pressure-sensitive adhesive composition may further contain a crosslinking agent, a silane compound, an antistatic agent, and the like.

The (meth)acrylic resin contained in the pressure-sensitive adhesive composition is preferably a polymer (hereinafter also referred to as a "(meth)acrylic acid ester polymer") having as its main component (e.g., containing 50 parts by mass or more per 100 parts by mass of the structural unit of the (meth)acrylic resin) a structural unit derived from a (meth)acrylic acid alkyl ester represented by the following formula (I) (hereinafter also referred to as "structural unit (I)"):
In this specification, the term "(meth)acrylic resin" refers to at least one of an acrylic resin and a methacrylic resin, and the same applies to (meth)acrylate and (meth)acryloyl.

［式（Ｉ）中、
Ｒ^１０は、水素原子又はメチル基を表し、Ｒ^２０は、炭素数１～２０のアルキル基を表し、アルキル基は直鎖状、分岐状及び環状のうちのいずれの構造を有していてもよく、アルキル基の水素原子は、炭素数１～１０のアルコキシ基で置き換わっていてもよい。］

[In formula (I),
R ¹⁰ represents a hydrogen atom or a methyl group, R ²⁰ represents an alkyl group having 1 to 20 carbon atoms, the alkyl group may have any of a linear, branched, and cyclic structure, and the hydrogen atom of the alkyl group may be replaced by an alkoxy group having 1 to 10 carbon atoms.

Examples of the (meth)acrylic acid ester represented by formula (I) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, i-hexyl (meth)acrylate, n-heptyl (meth)acrylate, and n- Examples of the alkyl acrylate containing an alkoxy group include 2-methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and the like. Among these, it is preferable to include n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate, n- and i-nonyl (meth)acrylate, n-decyl (meth)acrylate, i-decyl (meth)acrylate, n-dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, stearyl (meth)acrylate, and t-butyl (meth)acrylate. Specific examples of the alkyl acrylate containing an alkoxy group include 2-methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and the like. Among these, it is preferable to include n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate, and it is particularly preferable to include n-butyl (meth)acrylate.

The (meth)acrylic acid ester polymer may contain a structural unit derived from a monomer other than the structural unit (I). The structural unit derived from the other monomer may be one type or two or more types. Examples of other monomers that the (meth)acrylic acid ester polymer may contain include a monomer having a polar functional group, a monomer having an aromatic group, and an acrylamide monomer.

Monomers having a polar functional group include (meth)acrylates having a polar functional group. Examples of the polar functional group include a hydroxy group; a carboxy group; an unsubstituted or substituted amino group substituted with an alkyl group having 1 to 6 carbon atoms; and a heterocyclic group such as an epoxy group.

The content of structural units derived from monomers having polar functional groups in the (meth)acrylic acid ester polymer is preferably 10 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, even more preferably 0.5 parts by mass or more and 5 parts by mass or less, and particularly preferably 1 part by mass or more and 5 parts by mass or less, relative to 100 parts by mass of all structural units of the (meth)acrylic acid ester polymer.

Examples of monomers having an aromatic group include (meth)acrylic acid esters having one (meth)acryloyl group and one or more aromatic rings (e.g., benzene ring, naphthalene ring, etc.) in the molecule, and having a phenyl group, a phenoxyethyl group, or a benzyl group.

The content of structural units derived from monomers having aromatic groups in the (meth)acrylic acid ester polymer is preferably 20 parts by mass or less, more preferably 4 parts by mass or more and 20 parts by mass or less, and even more preferably 4 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of all structural units of the (meth)acrylic acid ester polymer.

Examples of acrylamide monomers include N-(methoxymethyl)acrylamide, N-(ethoxymethyl)acrylamide, N-(propoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, and N-(2-methylpropoxymethyl)acrylamide. By including these structural units, it is possible to suppress the bleeding out of additives such as antistatic agents, which will be described later.

Furthermore, structural units derived from monomers other than structural unit (I) may include structural units derived from styrene-based monomers, structural units derived from vinyl-based monomers, structural units derived from monomers having multiple (meth)acryloyl groups in the molecule, etc.

The weight average molecular weight (hereinafter also simply referred to as "Mw") of the (meth)acrylic resin is preferably 500,000 to 2,500,000. If the weight average molecular weight is 500,000 or more, the durability of the adhesive layer in high temperature and high humidity environments can be improved. If the weight average molecular weight is 2,500,000 or less, the operability when applying a coating liquid containing the adhesive composition is improved. The molecular weight distribution (Mw/Mn), which is expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (hereinafter also simply referred to as "Mn"), is usually 2 to 10. In this specification, "weight average molecular weight" and "number average molecular weight" are polystyrene-equivalent values measured by gel permeation chromatography (GPC).

When the (meth)acrylic resin is dissolved in ethyl acetate to give a solution with a concentration of 20% by mass, the viscosity at 25°C is preferably 20 Pa·s or less, and more preferably 0.1 to 15 Pa·s. If the viscosity of the (meth)acrylic resin at 25°C is within the above range, it contributes to improved durability and reworkability of the optical laminate including the pressure-sensitive adhesive layer formed from the resin and the laminate with the optical film. The above viscosity can be measured using a Brookfield viscometer.

The glass transition temperature (Tg) of the (meth)acrylic resin is, for example, −60 to 20° C., preferably −50 to 15° C., more preferably −45 to 10° C., and even more preferably −40 to 0° C. The glass transition temperature can be measured by a differential scanning calorimeter (DSC).

The (meth)acrylic resin may contain two or more types of (meth)acrylic acid ester polymers. Examples of such (meth)acrylic acid ester polymers include those that are mainly composed of structural units (I) derived from the above-mentioned (meth)acrylic acid esters and have a relatively low molecular weight, such as a (meth)acrylic acid ester polymer with a weight average molecular weight in the range of 50,000 to 300,000.

(Meth)acrylic resins can usually be produced by known polymerization methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. In producing (meth)acrylic resins, polymerization is usually carried out in the presence of a polymerization initiator. The amount of polymerization initiator used is usually 0.001 to 5 parts by mass per 100 parts by mass of the total of all monomers constituting the (meth)acrylic resin. (Meth)acrylic resins can also be produced by a method of polymerization using active energy rays such as ultraviolet rays.

The pressure-sensitive adhesive composition preferably contains a crosslinking agent. Examples of crosslinking agents include conventional crosslinking agents (e.g., isocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, peroxides, etc.), and from the viewpoints of the pot life of the pressure-sensitive adhesive composition, crosslinking speed, and durability of the optical laminate and the laminate with the optical film, it is particularly preferable to use an isocyanate compound.

The isocyanate compound is a compound having at least two isocyanato groups (-NCO) in the molecule. Specific examples include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate. In addition, adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, and dimers and trimers of these isocyanate compounds are also included. Two or more types of isocyanate compounds may be combined.

The content of the crosslinking agent in the pressure-sensitive adhesive composition is, for example, 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 1 part by mass, per 100 parts by mass of the (meth)acrylic resin.

The adhesive composition may further contain a silane compound. Examples of the silane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylethoxydimethylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane. The silane compound may contain an oligomer derived from the above silane compound.

The content of the silane compound in the adhesive composition is usually 0.01 to 10 parts by mass, and preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (meth)acrylic resin. When the content of the silane compound is 0.01 parts by mass or more, the adhesion between the adhesive layer and the adherend tends to be improved, and when the content is 10 parts by mass or less, bleeding out of the silane compound from the adhesive layer tends to be suppressed.

The pressure-sensitive adhesive composition may further include an antistatic agent. Examples of the antistatic agent include known ones, and ionic antistatic agents are preferred. Examples of the cationic component constituting the ionic antistatic agent include organic cations and inorganic cations. Examples of the organic cation include pyridinium cation, imidazolium cation, ammonium cation, sulfonium cation, phosphonium cation, etc. Examples of the inorganic cation include alkali metal cations such as lithium cation, potassium cation, sodium cation, and cesium cation, and alkaline earth metal cations such as magnesium cation and calcium cation. The anionic component constituting the ionic antistatic agent may be either an inorganic anion or an organic anion, but an anionic component containing a fluorine atom is preferred in terms of excellent antistatic performance. Examples of the anion component containing a fluorine atom include a hexafluorophosphate anion (PF ₆ ⁻ ), a bis(trifluoromethanesulfonyl)imide anion [(CF ₃ SO ₂ ) ₂ N ⁻ ], and a bis(fluorosulfonyl)imide anion [(FSO ₂ ) ₂ N ⁻ ] anion.

Ionic antistatic agents that are solid at room temperature are preferred because they provide excellent stability over time in the antistatic performance of the pressure-sensitive adhesive composition.

The content of the antistatic agent in the pressure-sensitive adhesive composition is, for example, 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 1 to 7 parts by mass, per 100 parts by mass of the (meth)acrylic resin.

The adhesive composition may contain one or more additives such as ultraviolet absorbers, solvents, crosslinking catalysts, tackifiers, and plasticizers. It is also useful to blend an ultraviolet-curable compound into the adhesive composition, form an adhesive layer, and then irradiate the adhesive with ultraviolet light to cure the compound, thereby forming a harder adhesive layer.

The adhesive layer can be formed, for example, by dissolving or dispersing the adhesive composition in a solvent to form a solvent-containing adhesive composition, which is then applied to the surface of the layer on which the adhesive layer is to be formed, and then dried.

The thickness of the adhesive layer is usually 0.1 μm or more and 30 μm or less, preferably 3 μm or more and 30 μm or less, more preferably 5 μm or more and 25 μm or less, and particularly preferably 5 μm or more and 10 μm or less.

Since the first liquid crystal retardation layer of the optical laminate has a small thickness, the thickness of the optical laminate is also small. When the optical laminate has an adhesive layer, it is preferable that the storage modulus G' of the adhesive layer at a temperature of 23 ° C is also small. This makes it easier to suppress the occurrence of scratches in the first liquid crystal retardation layer 11 during product processing, etc. The storage modulus G' of the adhesive layer at a temperature of 23 ° C is preferably 5 MPa or less, more preferably 1 MPa or less, even more preferably 0.5 MPa or less, even more preferably 0.2 MPa or less, and particularly preferably 0.1 MPa or less. The storage modulus G' of the adhesive layer at a temperature of 23 ° C is usually 0.001 MPa or more, and may be 0.01 MPa or more. The storage modulus G' can be measured at a temperature of 23°C in accordance with JIS K7244-6 using a viscoelasticity measuring device (Physica, MCR300) by the torsional shear method (normal force FN: 1N, strain γ: 1%, frequency: 1Hz).

(Adhesive Layer)
The adhesive layer can have a function of bonding a polarizer and a polarizing element protective film, a function of bonding an optical film and a first liquid crystal retardation layer, a function of bonding members constituting the optical film (for example, a polarizing plate and a second liquid crystal retardation layer), etc. The adhesive layer can be formed from an adhesive composition.

Examples of adhesive compositions include aqueous adhesive compositions, and curable adhesive compositions that are cured by heating or irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Examples of aqueous adhesive compositions include those in which a polyvinyl alcohol resin or a urethane resin is dissolved in water as the main component, and those in which a polyvinyl alcohol resin or a urethane resin is dispersed in water as the main component. The aqueous adhesive composition may further contain a curable component or a crosslinking agent such as a polyhydric aldehyde, a melamine compound, a zirconia compound, a zinc compound, a glyoxal compound, or a water-soluble epoxy resin. Examples of aqueous adhesive compositions include the adhesive composition described in JP 2010-191389 A, the adhesive composition described in JP 2011-107686 A, the composition described in JP 2020-172088 A, and the composition described in JP 2005-208456 A.

The curable adhesive composition is preferably an active energy ray-curable adhesive composition that contains a curable (polymerizable) compound as a main component and is cured by irradiation with active energy rays. The active energy ray-curable adhesive composition is more preferably a photocurable adhesive composition that is cured by irradiation with ultraviolet rays or visible light. Examples of active energy ray-curable adhesive compositions and photocurable adhesive compositions include cationic polymerization adhesive compositions that contain a cationic polymerizable compound as a curable compound, radical polymerization adhesive compositions that contain a radical polymerizable compound as a curable compound, and hybrid adhesive compositions that contain both a cationic polymerizable compound and a radical polymerizable compound as curable compounds.

Cationically polymerizable compounds are compounds or oligomers that undergo a cationic polymerization reaction and harden when exposed to active energy rays such as ultraviolet light, visible light, electron beams, or X-rays, or when heated. Specific examples include epoxy compounds, oxetane compounds, and vinyl compounds.

Epoxy compounds include alicyclic epoxy compounds (compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule) such as 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate; aromatic epoxy compounds (compounds having an aromatic ring and an epoxy group in the molecule) such as diglycidyl ether of bisphenol A; and aliphatic epoxy compounds (compounds having at least one oxirane ring bonded to an aliphatic carbon atom in the molecule) such as 2-ethylhexyl glycidyl ether and 1,4-butanediol diglycidyl ether.

Examples of oxetane compounds include compounds that have one or more oxetane rings in the molecule, such as 3-ethyl-3-{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane.

The cationic polymerization adhesive composition preferably contains a cationic polymerization initiator. The cationic polymerization initiator may be a thermal cationic polymerization initiator or a photo-induced cationic polymerization initiator. Examples of the cationic polymerization initiator include aromatic diazonium salts such as benzenediazonium hexafluoroantimonate; aromatic iodonium salts such as diphenyliodonium tetrakis(pentafluorophenyl)borate; aromatic sulfonium salts such as triphenylsulfonium hexafluorophosphate; and iron-arene complexes such as xylene-cyclopentadienyl iron(II) hexafluoroantimonate. The content of the cationic polymerization initiator in the adhesive composition is usually 0.1 to 10 parts by mass relative to 100 parts by mass of the cationic polymerizable compound. Two or more types of cationic polymerization initiators may be included.

Examples of cationic polymerization adhesive compositions include the cationic polymerization composition described in JP 2021-113969 A.

Radically polymerizable compounds are compounds or oligomers that undergo a radical polymerization reaction and harden when exposed to active energy rays such as ultraviolet rays, visible light, electron beams, or X-rays, or when heated. Specific examples of compounds that have ethylenically unsaturated bonds include (meth)acrylic compounds that have one or more (meth)acryloyl groups in the molecule, and vinyl compounds that have one or more vinyl groups in the molecule.

Examples of (meth)acrylic compounds include (meth)acrylate monomers having at least one (meth)acryloyloxy group in the molecule, (meth)acrylamide monomers, and (meth)acryl oligomers obtained by reacting two or more functional group-containing compounds and having at least two (meth)acryloyl groups in the molecule, and other (meth)acryloyl group-containing compounds.

The radical polymerization adhesive composition preferably contains a radical polymerization initiator. The radical polymerization initiator may be a thermal radical polymerization initiator or a photoradical polymerization initiator. Examples of the radical polymerization initiator include acetophenone-based initiators such as acetophenone and 3-methylacetophenone; benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone; benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone-based initiators such as 4-isopropylthioxanthone; xanthone, fluorenone, and the like. The content of the radical polymerization initiator in the adhesive composition is usually 0.1 to 10 parts by mass relative to 100 parts by mass of the radical polymerizable compound. Two or more types of radical polymerization initiators may be included.

Examples of radical polymerization adhesive compositions include the radical polymerizable compositions described in JP 2016-126345 A, JP 2016-153474 A, and WO 2017/183335 A.

The active energy ray-curable adhesive composition and the photocurable adhesive composition may contain additives such as ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow control agents, plasticizers, defoamers, antistatic agents, leveling agents, and solvents, as necessary.

The bonding of two layers with an adhesive layer can be carried out by applying an adhesive composition to at least one of the bonding surfaces of each of the two layers, superimposing the two layers with the coating layer of the adhesive composition therebetween, pressing the layers together from above and below using a lamination roll or the like, and then drying the coating layer, curing it by irradiating it with active energy rays, or curing it by heating.

Before forming the coating layer of the adhesive composition, at least one of the bonding surfaces of the two layers may be subjected to an easy-adhesion treatment such as saponification treatment, corona treatment, plasma treatment, primer treatment, anchor coating treatment, etc.

Various coating methods such as a die coater, comma coater, gravure coater, wire bar coater, doctor blade coater, etc. can be used to form a coating layer of the adhesive composition.

The irradiation intensity of the active energy rays when irradiating the active energy rays is determined for each composition of the active energy ray curable adhesive composition or the photocurable adhesive composition and is not particularly limited, but is preferably 10 mW/cm ² or more and 1000 mW/cm ² or less. The irradiation intensity is preferably an intensity in a wavelength region effective for activating a photopolymerization initiator such as a photocationic polymerization initiator or a photoradical polymerization initiator. It is preferable to irradiate once or multiple times with such light irradiation intensity, and the accumulated light amount is 10 mJ/cm ² or more, and more preferably 100 mJ/cm ² or more and 1,000 mJ/cm ² or less.

The light source used to polymerize and cure the active energy ray-curable adhesive composition or the photocurable adhesive composition is not particularly limited, but examples include low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, xenon lamps, halogen lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

The thickness of the adhesive layer formed from the aqueous adhesive composition may be, for example, 5 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less, and may be 0.01 μm or more, and preferably 0.05 μm or more.

The thickness of the adhesive layer formed from the active energy ray-curable adhesive composition or the photocurable adhesive composition may be, for example, 10 μm or less, preferably 5 μm or less, and more preferably 3 μm or less, and may be 0.1 μm or more, preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more.

<First liquid crystal retardation layer, second liquid crystal retardation layer>
The first liquid crystal retardation layer and the second liquid crystal retardation layer are respectively a first polymer layer and a second polymer layer (hereinafter also simply referred to as "polymer layer") containing a polymer of a polymerizable liquid crystal compound. The first liquid crystal retardation layer may be a multilayer of a first polymer layer and a first alignment layer, and the second liquid crystal retardation layer may be a multilayer of a second polymer layer and a second alignment layer. It may be a multi-layer body.

The first liquid crystal retardation layer is obtained by applying a composition for forming a first liquid crystal retardation layer containing a polymerizable liquid crystal compound onto a first base layer or a first alignment layer to form an aligned polymer of the polymerizable liquid crystal compound. The second liquid crystal retardation layer is obtained by applying a composition for forming a second liquid crystal retardation layer containing a polymerizable liquid crystal compound onto a second base layer or a second alignment layer to form an aligned polymer of the polymerizable liquid crystal compound. Forming a liquid crystal retardation layer in this manner is preferable in terms of being able to design a thin film and wavelength dispersion characteristics as desired. The first liquid crystal retardation layer forming composition and the second liquid crystal retardation layer forming composition may each independently further contain a solvent, a photopolymerization initiator, a photosensitizer, an antioxidant, a leveling agent, an adhesion agent, and the like.

The liquid crystal retardation layer (first liquid crystal retardation layer or second liquid crystal retardation layer) is usually a film in which a polymerizable liquid crystal compound is hardened in an oriented state, and in order to generate a retardation in the viewing plane, it usually contains a polymer layer (first polymer layer or second polymer layer) made of a hardened film in which the polymerizable group is polymerized in a state in which the polymerizable liquid crystal compound is oriented horizontally relative to the surface of the base layer (first base layer or second base layer). In this case, if the polymerizable liquid crystal compound is a rod-shaped liquid crystal, it is sufficient to use a positive A plate, and if the polymerizable liquid crystal compound is a disc-shaped liquid crystal, it is sufficient to use a negative A plate.

The optical laminate or the laminate with the optical film may include a polarizing element and a first liquid crystal retardation layer and have an anti-reflection function. In order for the optical laminate or the laminate with the optical film to achieve a high level of anti-reflection function, it is sufficient to have a λ/4 plate function (i.e., a π/2 retardation function) in the entire visible light range. Specifically, it is preferable to have a reverse wavelength dispersion λ/4 layer, or to combine two or more liquid crystal retardation layers with different orientations. For example, it may be a combination of a liquid crystal retardation layer having a λ/2 plate function (i.e., a π retardation function) and a liquid crystal retardation layer having a λ/4 plate function (i.e., a π/2 retardation function).

From the viewpoint of compensating for the anti-reflection function in oblique directions, it is preferable that the optical laminate and the laminate with the optical film further include a layer having anisotropy in the thickness direction (positive C plate). In addition, each liquid crystal retardation layer may have a tilt alignment or may form a cholesteric alignment state.

When the optical laminate or the laminate with the optical film has an anti-reflection function and functions as a circular polarizer, the first liquid crystal retardation layer is preferably a λ/4 liquid crystal retardation layer that gives a phase difference of λ/4. When the optical laminate or the laminate with the optical film has a first liquid crystal retardation layer and a second liquid crystal retardation layer and functions as a circular polarizer, [i] the first liquid crystal retardation layer and the second liquid crystal retardation layer may be a combination of a λ/4 liquid crystal retardation layer and a λ/2 liquid crystal retardation layer that gives a phase difference of λ/2, or [ii] the first liquid crystal retardation layer and the second liquid crystal retardation layer may be a combination of a positive C plate and a λ/4 liquid crystal retardation layer.

The λ/4 function over the entire visible light range preferably satisfies the optical characteristics shown in the following formula (1), where R(λ) is the in-plane retardation for light with a wavelength of λ nm, and more preferably satisfies the optical characteristics shown in the following formulas (1), (2), and (3).
100nm<Re(550)<160nm (1)
Re(450)/Re(550)≦1.0 (2)
1.00≦Re(650)/Re(550) (3)
[In formulas (1) to (3),
Re(450) represents the in-plane phase difference value (in-plane retardation) for light having a wavelength of 450 nm,
Re(550) represents an in-plane retardation value for light having a wavelength of 550 nm;
Re(650) represents an in-plane retardation value for light having a wavelength of 650 nm.

If the "Re(450)/Re(550)" of the liquid crystal retardation layer exceeds 1.0, the light leakage on the short wavelength side of the elliptical polarizing plate having the liquid crystal retardation layer increases. The value of "Re(450)/Re(550)" is preferably 0.7 or more and 1.0 or less, more preferably 0.80 or more and 0.95 or less, even more preferably 0.80 or more and 0.92 or less, and particularly preferably 0.82 or more and 0.88 or less. The value of "Re(450)/Re(550)" can be adjusted arbitrarily by adjusting the mixing ratio of the polymerizable liquid crystal compound, the stacking angle of the multiple liquid crystal retardation layers, and the retardation value.

The in-plane retardation value of the liquid crystal retardation layer can be adjusted by the thickness of the liquid crystal retardation layer. Since the in-plane retardation value is determined by the following formula (4), in order to obtain a desired in-plane retardation value (Re(λ)), Δn(λ) and the thickness d may be adjusted. The thickness of the liquid crystal retardation layer is usually 10 μm or less, preferably 0.3 μm or more and 5 μm or less, more preferably 0.5 μm or more and 5 μm or less, and even more preferably 1 μm or more and 3 μm or less. The thickness of the liquid crystal retardation layer can be measured by an interference film thickness meter, a laser microscope, or a stylus film thickness meter. Δn(λ) in formula (4) depends on the molecular structure of the polymerizable liquid crystal compound described later.
Re(λ)=d×Δn(λ) (4)
[In the formula, Re(λ) represents an in-plane retardation value at a wavelength of λ nm, d represents a film thickness, and Δn(λ) represents a birefringence at a wavelength of λ nm.]

As one method for achieving anti-reflection performance, a configuration in which a layer having a positive wavelength dispersion λ/2 layer and a layer having a positive wavelength dispersion λ/4 layer are combined is known. For example, this can be obtained by combining a layer having optical properties represented by formulas (5), (7), and (8) with a layer having optical properties represented by formulas (6), (7), and (8) in a specific slow axis relationship.
100nm<Re(550)<160nm (5)
200nm<Re(550)<320nm (6)
Re(450)/Re(550)≧1.00 (7)
1.00≧Re(650)/Re(550) (8)
[In formulas (5) to (8),
Re(450) represents an in-plane retardation value for light having a wavelength of 450 nm;
Re(550) represents an in-plane retardation value for light having a wavelength of 550 nm;
Re(650) represents an in-plane retardation value for light with a wavelength of 650 nm.]

Methods for combining the above layers include well-known methods such as those described in JP 2015-163935 A and WO 2013/137464. From the viewpoint of viewing angle compensation, it is preferable to use a λ/2 liquid crystal retardation layer containing a polymer of a disc-shaped polymerizable liquid crystal compound and a λ/4 liquid crystal retardation layer containing a polymer of a rod-shaped polymerizable liquid crystal compound.

An example of a disc-shaped polymerizable liquid crystal compound is a compound containing a group represented by formula (W) (hereinafter, sometimes referred to as a polymerizable liquid crystal compound).

［式（Ｗ）中、Ｒ^４０は、下記式（Ｗ－１）～（Ｗ－５）を表す。

In formula (W), R ⁴⁰ represents any one of the following formulae (W-1) to (W-5).

［式（Ｗ－１）～（Ｗ－５）中、
Ｘ^４０及びＺ^４０は、炭素数１～１２のアルカンジイル基を表し、該アルカンジイル基に含まれる水素原子は、炭素数１～５のアルコキシ基で置換されていてもよく、該アルコキシ基に含まれる水素原子は、ハロゲン原子で置換されていてもよい。また、該アルカンジイル基を構成する－ＣＨ_２－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよい。
ｍ２は、整数を表す。］］

[In formulas (W-1) to (W-5),
X ⁴⁰ and Z ⁴⁰ each represent an alkanediyl group having 1 to 12 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms. The hydrogen atoms contained therein may be substituted with halogen atoms, and —CH ₂ — constituting the alkanediyl group may be substituted with —O— or —CO—.
m2 represents an integer.

Examples of the rod-shaped polymerizable liquid crystal compound include compounds represented by formula (II), formula (III), formula (IV), formula (V), formula (VI), or formula (VII).
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-B16-E12-B17-P12 (II)
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-F11 (III)
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-E12-B17-P12 (IV)
P11-B11-E11-B12-A11-B13-A12-B14-A13-F11 (V)
P11-B11-E11-B12-A11-B13-A12-B14-E12-B17-P12 (VI)
P11-B11-E11-B12-A11-B13-A12-F11 (VII)
[In formulas (II) to (VII),
A11 to A14 each independently represent a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group. A hydrogen atom contained in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, or a nitro group, and a hydrogen atom contained in the alkyl group having 1 to 6 carbon atoms and the alkoxy group having 1 to 6 carbon atoms may be substituted with a fluorine atom.
B11 and B17 each independently represent -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -CO-NR ¹⁶ -, -NR ¹⁶ -CO-, -CO-, -CS-, or a single bond, and R ¹⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
B12 to B16 each independently represent -C≡C-, -CH=CH-, -CH ₂ -CH ₂ -, -O-, -S-, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -O-C(=O)-O-, -CH=N-, -N=CH-, -N=N-, -C(=O)-NR ¹⁶ -, -NR ¹⁶ -C(=O)-, -OCH ₂ -, -OCF ₂ -, -CH 2 O-, -CF _{2 O-} , -CH=CH-C(=O)-O-, -O-C(=O)-CH=CH- or a single bond.
E11 and E12 each independently represent an alkanediyl group having 1 to 12 carbon atoms, a hydrogen atom contained in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, a hydrogen atom contained in the alkoxy group may be substituted with a halogen atom, and -CH ₂ - constituting the alkanediyl group may be replaced with -O- or -CO-.
F11 represents a hydrogen atom, an alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, a dimethylamino group, a hydroxy group, a methylol group, a formyl group, a sulfo group (—SO ₃ H), a carboxy group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or a halogen atom, and —CH ₂ — constituting the alkyl group and the alkoxy group may be replaced by —O—.
P11 and P12 each independently represent a polymerizable group.

In addition to the above-mentioned configuration combining a positive wavelength dispersion λ/2 layer and a positive wavelength dispersion λ/4 layer, configurations with tilt alignment or cholesteric alignment can also be used without any particular restrictions as long as they achieve anti-reflection function. Examples of such configurations include those described in WO2021/060378, WO2021/132616, WO2021/132624, etc.

The positive C plate is not particularly limited as long as it has anisotropy in the thickness direction, but if it does not have tilt alignment or cholesteric alignment, it has optical characteristics represented by the following formula (9).
nx≒ny<nz (9)
[In formula (9),
nx represents the principal refractive index at a wavelength λ [nm] in the plane of the positive C plate.
ny represents the refractive index of the positive C plate at a wavelength λ [nm] in a direction perpendicular to nx in the same plane as nx.
nz(λ) represents the refractive index at a wavelength λ [nm] in the thickness direction of the positive C plate.
If nx≈ny, nx can be the refractive index in any direction in the plane of the positive C-plate.

The in-plane retardation value Re(550) of the positive C plate at a wavelength of 550 nm is usually in the range of 0 nm to 10 nm, and preferably in the range of 0 nm to 5 nm. The retardation value Rth(550) in the thickness direction at a wavelength of 550 nm is usually in the range of -170 nm to -10 nm, and preferably in the range of -150 nm to -20 nm, and more preferably in the range of -100 nm to -40 nm. If the retardation value in the thickness direction is in this range, the anti-reflection properties from oblique directions can be further improved.

When the positive C plate is a liquid crystal retardation layer, its thickness is usually 10 μm or less, preferably 5 μm or less, and more preferably 0.3 μm or more and 3 μm or less.

The positive C plate is preferably a liquid crystal retardation layer. More preferably, it is a rod-shaped polymerizable liquid crystal compound. Examples of rod-shaped polymerizable liquid crystal compounds include the compounds represented by the above formulas (II) to (VII).

(Polymerizable Liquid Crystal Compound Constituting Liquid Crystal Retardation Layer)
The polymerizable liquid crystal compound contained in the first liquid crystal retardation layer forming composition and the second liquid crystal retardation layer forming composition (hereinafter also referred to as "liquid crystal retardation layer forming composition") means a liquid crystal compound having a polymerizable group, particularly a photopolymerizable group, and as the polymerizable liquid crystal compound, a conventionally known polymerizable liquid crystal compound can be used. The photopolymerizable group refers to a group that can be involved in a polymerization reaction by a reactive species generated from a photopolymerization initiator, such as an active radical or an acid. Examples of the photopolymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. The polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, but a thermotropic liquid crystal is preferred in terms of the ability to precisely control the film thickness. The phase ordered structure of the thermotropic liquid crystal may be nematic or smectic. The polymerizable liquid crystal compound may be rod-shaped or discotic. The polymerizable liquid crystal compound may be used alone or in combination of two or more kinds.

As the polymerizable liquid crystal compound, from the viewpoint of expressing reverse wavelength dispersion, liquid crystals having a T-shaped or H-shaped mesogen structure that also has birefringence in the direction perpendicular to the molecular long axis direction are preferred, and from the viewpoint of obtaining stronger dispersion, T-shaped liquid crystals are more preferred. Specific examples of the T-shaped liquid crystal structure include compounds represented by the following formula (VIII).

［式（ＶＩＩＩ）中、
Ａｒは置換基を有していてもよい二価の芳香族基を表す。該二価の芳香族基中には窒素原子、酸素原子、硫黄原子のうち少なくとも１つ以上が含まれることが好ましい。二価の基Ａｒに含まれる芳香族基が２つ以上である場合、２つ以上の芳香族基は互いに単結合、－ＣＯ－Ｏ－、－Ｏ－等の二価の結合基で結合していてもよい。
Ｇ^１及びＧ^２はそれぞれ独立に、二価の芳香族基又は二価の脂環式炭化水素基を表す。ここで、該二価の芳香族基又は二価の脂環式炭化水素基に含まれる水素原子は、ハロゲン原子、炭素数１～４のアルキル基、炭素数１～４のフルオロアルキル基、炭素数１～４のアルコキシ基、シアノ基又はニトロ基に置換されていてもよく、該二価の芳香族基又は二価の脂環式炭化水素基を構成する炭素原子が、酸素原子、硫黄原子又は窒素原子に置換されていてもよい。
Ｌ^１、Ｌ^２、Ｂ^１及びＢ^２はそれぞれ独立に、単結合又は二価の連結基である。
ｋ、ｌは、それぞれ独立に０～３の整数を表し、１≦ｋ＋ｌの関係を満たす。ここで、２≦ｋ＋ｌである場合、Ｂ^１及びＢ^２、Ｇ^１及びＧ^２は、それぞれ互いに同一であってもよく、異なっていてもよい。
Ｅ^１及びＥ^２はそれぞれ独立に、炭素数１～１７のアルカンジイル基を表し、ここで、アルカンジイル基に含まれる水素原子は、ハロゲン原子で置換されていてもよく、該アルカンジイル基に含まれる－ＣＨ_２－は、－Ｏ－、－Ｓ－、－ＣＯＯ－で置換されていてもよく、－Ｏ－、－Ｓ－、－ＣＯＯ－を複数有する場合は互いに隣接しない。
Ｐ^１及びＰ^２は互いに独立に、重合性基又は水素原子を表し、少なくとも１つは重合性基である。］

[In formula (VIII),
Ar represents a divalent aromatic group which may have a substituent. The divalent aromatic group preferably contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. When the divalent group Ar contains two or more aromatic groups, the two or more aromatic groups are bonded to each other via a divalent bonding group such as a single bond, -CO-O-, or -O-. It is okay to do so.
^G1 and ^G2 each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. a hydrogen atom contained therein may be substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group; A carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom.
L ¹ , L ² , B ¹ and B ² each independently represent a single bond or a divalent linking group.
k and l each independently represent an integer of 0 to 3, and satisfy the relationship of 1≦k+l. When 2≦k+l, B ¹ and B ² , and G ¹ and G ² are the same as each other. may be the same or may be different.
^E1 and ^E2 each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein a hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and The contained —CH ₂ — may be replaced by —O—, —S—, —COO—, and when there are a plurality of —O—, —S—, —COO—, they are not adjacent to each other.
P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

G ¹ and G ² are each independently preferably a 1,4-phenylenediyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, or a 1,4-cyclohexanediyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a 1,4-phenylenediyl group substituted with a methyl group, an unsubstituted 1,4-phenylenediyl group, or an unsubstituted 1,4-trans-cyclohexanediyl group, and particularly preferably an unsubstituted 1,4-phenylenediyl group, or an unsubstituted 1,4-trans-cyclohexanediyl group.
At least one of a plurality of ^G1 and ^G2 is preferably a divalent alicyclic hydrocarbon group, and more preferably at least one of ^G1 and ^G2 bonded to ^L1 or ^L2 is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2 -, -R ^a3 COOR ^a4 -, -R ^a5 OCOR ^a6 -, R ^a7 OC═OOR ^a8 -, -N═N-, -CR ^c ═CR ^d -, or -C≡C-, where R ^a1 to R ^a8 are each independently a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d are an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a4-1 -, or OCOR ^a6-1 -. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent a single bond, -CH ₂ -, or -CH ₂ CH ₂ -. ^{L 1} and L ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or -OCO-.

B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 OR ^a10 -, -R ^a11 COOR ^a12 -, -R ^a13 OCOR ^a14 -, or -R ^a15 OC═OOR ^a16 -. Here, R ^a9 to R ^a16 are each independently a single bond, or an alkylene group having 1 to 4 carbon atoms. ^{B 1} and B ² are each independently more preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a12-1 -, or -OCOR ^a14-1 -. Here, R ^a10-1 , R ^a12-1 and R ^a14-1 each independently represent a single bond, -CH ₂ - or -CH ₂ CH ₂ -. ^{B 1} and B ² each independently represent more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, -OCO- or -OCOCH ₂ CH ₂ -.

From the viewpoint of expressing reverse wavelength dispersion, k and l are preferably in the range of 2≦k+l≦6, preferably k+l=4, and more preferably k=2 and l=2. k=2 and l=2 are preferable because they result in a symmetrical structure.

E ¹ and E ² each independently preferably represent an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

Examples of the polymerizable group represented by ^P1 or ^P2 include an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. Among these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferred, and an acryloyloxy group is more preferred.

It is preferable that Ar has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring, and a benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Among them, it is preferable that Ar has a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is more preferable that Ar has a benzothiazole group. In addition, when Ar contains a nitrogen atom, it is preferable that the nitrogen atom has π electrons.

In formula (VIII), the total number _Nπ of π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, even more preferably 14 or more, and particularly preferably 16 or more. Also, it is preferably 30 or less, more preferably 26 or less, and even more preferably 24 or less.

Suitable examples of the aromatic group represented by Ar include the following groups.

In formulas (Ar-1) to (Ar-23),
The * marks indicate connecting parts.
Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N,N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 12 carbon atoms, or an N,N-dialkylsulfamoyl group having 2 to 12 carbon atoms.
Q ¹ and Q ² each independently represent -CR ^{2 '} R ^{3 '} -, -S-, -NH-, -NR ^{2 '} -, -CO- or O-; R ^{2 '} and R ^{3 '} each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.
Y ¹ , Y ² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.
W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom.
m represents an integer of 0 to 6.

Examples of the aromatic hydrocarbon group in ^Y1 , ^Y2 , and ^Y3 include aromatic hydrocarbon groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group, of which a phenyl group and a naphthyl group are preferred, and a phenyl group is more preferred. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 4 to 20 carbon atoms and containing at least one heteroatom, such as a nitrogen atom, an oxygen atom, or a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group, of which a furyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group are preferred.

^Y1 , ^Y2 and ^Y3 may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

Z ⁰ , Z ¹ and Z ² are each preferably independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, or an alkoxy group having 1 to 12 carbon atoms, Z ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

^Q1 and ^Q2 are each preferably independently -NH-, -S-, ^-NR2'- or -O-, and R2 ^' is preferably a hydrogen atom. Among these, -S-, -O- or -NH- is particularly preferred.

Among formulas (Ar-1) to (Ar-23), formulas (Ar-6) and (Ar-7) are preferred from the viewpoint of molecular stability.

In formulae (Ar-16) to (Ar-23), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ^0. Examples of the aromatic heterocyclic group include those described above as aromatic heterocyclic rings that Ar may have, such as a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pyrrolidine ring. This aromatic heterocyclic group may have a substituent. In addition, Y ¹ may be, together with the nitrogen atom to which it is bonded and Z ⁰ , the aforementioned polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group which may be substituted. Examples include a benzofuran ring, a benzothiazole ring, and a benzoxazole ring.

Among the polymerizable liquid crystal compounds, compounds having a maximum absorption wavelength of 300 to 400 nm are preferred. When a photopolymerization initiator is contained in the liquid crystal retardation layer forming composition, the polymerization reaction and gelation of the polymerizable liquid crystal compound may progress during long-term storage. However, if the maximum absorption wavelength of the polymerizable liquid crystal compound is 300 to 400 nm, even if it is exposed to ultraviolet light during storage, the generation of reactive species from the photopolymerization initiator and the polymerization reaction and gelation of the polymerizable liquid crystal compound caused by the reactive species can be effectively suppressed. Therefore, it is advantageous in terms of the long-term stability of the polymerizable liquid crystal composition, and the orientation and uniformity of the film thickness of the obtained polymer layer (liquid crystal cured film) can be improved. The maximum absorption wavelength of the polymerizable liquid crystal compound can be measured using a UV-visible spectrophotometer in a solvent. The solvent is a solvent that can dissolve the polymerizable liquid crystal compound, and examples of the solvent include chloroform.

The content of the polymerizable liquid crystal compound in the liquid crystal retardation layer forming composition is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 98 parts by mass, and even more preferably 90 to 95 parts by mass, based on 100 parts by mass of the solid content of the liquid crystal retardation layer forming composition. If the content of the polymerizable liquid crystal compound is within the above range, it is advantageous from the viewpoint of the orientation of the resulting polymer layer (liquid crystal cured film). In this specification, the solid content of the liquid crystal retardation layer forming composition means all components excluding volatile components such as organic solvents from the liquid crystal retardation layer forming composition.

The liquid crystal retardation layer forming composition may further contain reactive additives such as a solvent, a leveling agent, a polymerization initiator, a photosensitizer, an antioxidant, a crosslinking agent, and an adhesion agent, and it is preferable that the composition contains a solvent or a leveling agent from the viewpoint of processability.

The liquid crystal retardation layer forming composition may contain a solvent. Since polymerizable liquid crystal compounds generally have high viscosity, dissolving the liquid crystal retardation layer forming composition in a solvent often facilitates application, and as a result, the liquid crystal retardation layer is often easily formed. The solvent is preferably one that can completely dissolve the polymerizable liquid crystal compound, and is preferably a solvent that is inactive to the polymerization reaction of the polymerizable liquid crystal compound.

Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone or propylene glycol methyl ether acetate, and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; aromatic hydrocarbon solvents such as toluene and xylene, and nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; and amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. These solvents may be used alone or in combination of two or more.

The content of the solvent is preferably 50 to 98% by mass relative to the total amount of the composition for forming the liquid crystal retardation layer. In other words, the content of the solid content in the composition for forming the liquid crystal retardation layer is preferably 2 to 50% by mass, more preferably 5 to 30% by mass. If the content of the solid content is 50% by mass or less, the viscosity of the composition for forming the liquid crystal retardation layer is low, and the thickness of the liquid crystal retardation layer becomes approximately uniform, so that the liquid crystal retardation layer tends to be less prone to unevenness. In addition, the content of the solid content can be determined in consideration of the thickness of the liquid crystal retardation layer to be manufactured.

The liquid crystal retardation layer forming composition may contain a leveling agent. The leveling agent is an additive that adjusts the fluidity of the liquid crystal retardation layer forming composition and makes the film obtained by applying the liquid crystal retardation layer forming composition flatter. Examples of the leveling agent include organic modified silicone-based, polyacrylate-based and perfluoroalkyl-based leveling agents. Among them, when horizontal alignment is performed, polyacrylate-based and perfluoroalkyl-based leveling agents are preferred, and when vertical alignment is performed, organic modified silicone-based and perfluoroalkyl-based leveling agents are preferred.

When the liquid crystal retardation layer forming composition contains a leveling agent, the amount is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the amount of the leveling agent is within the above range, the polymerizable liquid crystal compound is easily aligned horizontally, and the resulting liquid crystal retardation layer tends to be smoother. When the amount of the leveling agent relative to the polymerizable liquid crystal compound exceeds the above range, the resulting liquid crystal retardation layer tends to be uneven. The liquid crystal retardation layer forming composition may contain two or more types of leveling agents.

The liquid crystal retardation layer forming composition may contain a polymerization initiator. The polymerization initiator is a compound that can initiate a polymerization reaction of a polymerizable liquid crystal compound or the like. As the polymerization initiator, a photopolymerization initiator that generates active radicals by the action of light is preferable from the viewpoint of not depending on the phase state of the thermotropic liquid crystal.

The photopolymerization initiator may be any known photopolymerization initiator, so long as it is a compound capable of initiating the polymerization reaction of the polymerizable liquid crystal compound. Specific examples include photopolymerization initiators capable of generating active radicals or acids under the action of light, and among these, photopolymerization initiators that generate radicals under the action of light are preferred. The photopolymerization initiators may be used alone or in combination of two or more kinds.

As the photopolymerization initiator, a known photopolymerization initiator can be used. For example, as a photopolymerization initiator that generates active radicals, self-cleavage type benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. can be used, and hydrogen abstraction type benzophenone compounds, alkylphenone compounds, benzoin ether compounds, benzyl ketal compounds, dibenzosuberone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, halogenoacetophenone compounds, dialkoxyacetophenone compounds, halogenobisimidazole compounds, halogenotriazine compounds, triazine compounds, etc. can be used. As a photopolymerization initiator that generates acid, iodonium salts and sulfonium salts can be used. From the viewpoint of excellent reaction efficiency at low temperatures, self-cleavage type photopolymerization initiators are preferred, and acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, and oxime ester compounds are particularly preferred.

The content of the polymerization initiator in the liquid crystal retardation layer forming composition can be adjusted appropriately depending on the type and amount of the polymerizable liquid crystal compound, but is usually 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the above range, polymerization can be performed without disturbing the alignment of the polymerizable liquid crystal compound.

The liquid crystal retardation layer forming composition may contain a sensitizer. The sensitizer is preferably a photosensitizer. Examples of the sensitizer include xanthone compounds such as xanthone and thioxanthone (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene compounds such as anthracene and alkoxy group-containing anthracene (e.g., dibutoxyanthracene, etc.); phenothiazine, rubrene, etc.

When the liquid crystal retardation layer forming composition contains a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the liquid crystal retardation layer forming composition can be further promoted. The amount of such a sensitizer used is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound.

In order to ensure stable progress of the polymerization reaction, the liquid crystal retardation layer may contain an antioxidant. The antioxidant can control the degree of progress of the polymerization reaction of the polymerizable liquid crystal compound.

The antioxidant may be, for example, a primary antioxidant selected from a phenol-based antioxidant, an amine-based antioxidant, a quinone-based antioxidant, or a nitroso-based antioxidant, or a secondary antioxidant selected from a phosphorus-based antioxidant and a sulfur-based antioxidant.

When the liquid crystal retardation layer forming composition contains an antioxidant, the content of the antioxidant is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. The antioxidants can be used alone or in combination of two or more kinds. When the content of the antioxidant is within the above range, polymerization can be performed without disturbing the alignment of the polymerizable liquid crystal compound.

The liquid crystal retardation layer forming composition may contain a reactive additive. The reactive additive preferably has a carbon-carbon unsaturated bond, an active hydrogen reactive group, or a thiol group in its molecule. The "active hydrogen reactive group" here means a group that is reactive to a group having active hydrogen such as a carboxyl group (-COOH), a hydroxyl group (-OH), or an amino group (-NH ₂ ), and representative examples thereof include a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, and a maleic anhydride group. The number of reactive groups possessed by the reactive additive is usually 1 to 20, and preferably 1 to 10.

(Method of manufacturing liquid crystal retardation layer)
The liquid crystal retardation layer can be produced by applying a liquid crystal retardation layer-forming composition (a first liquid crystal retardation layer-forming composition or a second liquid crystal retardation layer-forming composition) onto a substrate layer (a first substrate layer or a second substrate layer) or onto an alignment layer (a first alignment layer or a second alignment layer) formed on the substrate layer.

Methods for applying the liquid crystal retardation layer forming composition onto the substrate layer or the alignment layer include extrusion coating, direct gravure coating, reverse gravure coating, CAP coating, slit coating, microgravure, die coating, inkjet, etc. Also included are methods of applying using a coater such as a dip coater, bar coater, or spin coater. Among these, when applying continuously in a roll-to-roll format, the application methods of the microgravure method, inkjet method, slit coating method, and die coating method are preferred, and when applying to a sheet substrate such as glass, the highly uniform spin coating method is preferred. When applying in a roll-to-roll format, an alignment layer can be formed by applying the alignment layer forming composition to the substrate layer, and the liquid crystal retardation layer forming composition can be continuously applied onto the resulting alignment layer.

Drying methods for removing the solvent contained in the composition for forming the liquid crystal retardation layer include, for example, natural drying, ventilation drying, heat drying, reduced pressure drying, and combinations of these. Of these, natural drying or heat drying is preferred. The drying temperature is preferably in the range of 0 to 200°C, more preferably in the range of 20 to 150°C, and even more preferably in the range of 50 to 130°C. The drying time is preferably 10 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes. The composition for forming the alignment layer can also be dried in the same manner.

As a method for polymerizing the polymerizable liquid crystal compound contained in the liquid crystal retardation layer forming composition, photopolymerization is preferred. Photopolymerization is performed by irradiating an active energy ray to a laminate in which a liquid crystal retardation layer forming composition containing a polymerizable liquid crystal compound is applied on a substrate layer or an alignment layer. The active energy ray to be irradiated is appropriately selected according to the type of polymerizable liquid crystal compound contained in the dried coating (particularly, the type of photopolymerizable functional group possessed by the polymerizable liquid crystal compound), the type of photopolymerization initiator when a photopolymerization initiator is contained, and the amount thereof. Specifically, one or more types of active energy rays selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α rays, β rays, and γ rays can be mentioned. Among them, ultraviolet light is preferred in that the progress of the polymerization reaction is easily controlled and that photopolymerization devices widely used in this field can be used, and it is preferable to select the type of polymerizable liquid crystal compound so that it can be photopolymerized by ultraviolet light.

Light sources of active energy rays include, for example, low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources emitting light in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave excited mercury lamps, metal halide lamps, etc.

The ultraviolet irradiation intensity is usually 10 mW/cm ² or more and 3,000 mW/cm ² or less. The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating a cationic polymerization initiator or a radical polymerization initiator. The time for irradiating ultraviolet light is usually 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and even more preferably 10 seconds to 1 minute. When irradiating once or a plurality of times with such ultraviolet irradiation intensity, the accumulated light amount is usually 10 mJ/cm ² or more and 3,000 mJ/cm ² or less, preferably 50 mJ/cm ² or more and 2,000 mJ/cm ² or less, and more preferably 100 mJ/cm ² or more and 1,000 mJ/cm ² or less. When the accumulated light amount is less than this range, the polymerizable liquid crystal compound may not be sufficiently cured and good transferability may not be obtained. Conversely, when the accumulated light amount is more than this range, the optical film including the liquid crystal retardation layer may be colored.

(Retardation film)
The retarder includes at least one liquid crystal retardation layer. The optical laminate and the optical film may include a retarder. For example, the first liquid crystal retardation layer included in the optical laminate and the second liquid crystal retardation layer included in the optical film may constitute the retarder.

(Base material layer (first base material layer, second base material layer))
Examples of the substrate layer include a glass substrate and a film substrate, and a film substrate is preferred, and a long rolled film is more preferred in terms of being capable of being produced continuously. Examples of the resin constituting the film substrate include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin-based resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid esters; polyacrylic acid esters; triphenyl ethers; and the like. Examples of plastics include cellulose esters such as acetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyether sulfone; polyether ketone; polyphenylene sulfide, and polyphenylene oxide. Among these, the most popular plastics for optical film applications are From the viewpoint of transparency during use, a film substrate made of a resin selected from the group consisting of triacetyl cellulose, cyclic olefin resin, polymethacrylic acid ester, and polyethylene terephthalate is more preferable.

Examples of commercially available cellulose ester substrates include "FUJITAC FILM" (manufactured by Fuji Photo Film Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (all manufactured by Konica Minolta Opto, Inc.).
Examples of commercially available cyclic olefin resins include "Topas" (registered trademark) (manufactured by Ticona (Germany)), "Arton" (registered trademark) (manufactured by JSR Corporation), "ZEONOR" (registered trademark), "ZEONEX" (registered trademark) (all manufactured by Zeon Corporation), and "Apel" (registered trademark) (manufactured by Mitsui Chemicals, Inc.). Such cyclic olefin resins can be formed into a film by known means such as a solvent casting method or a melt extrusion method to form a substrate. Commercially available cyclic olefin resin substrates can also be used. Examples of commercially available cyclic olefin resin substrates include "S-Cina" (registered trademark), "SCA40" (registered trademark) (all manufactured by Sekisui Chemical Co., Ltd.), "ZEONOR Film" (registered trademark) (manufactured by Optes Co., Ltd.), and "Arton Film" (registered trademark) (manufactured by JSR Corporation).

The thickness of the second substrate layer is preferably thin enough to allow practical handling, but if it is too thin, the strength decreases and processability tends to be poor. The thickness of the second substrate layer is usually 5 μm to 300 μm, preferably 10 μm to 200 μm, and more preferably 10 to 50 μm. In addition, a further thinning effect can be obtained by peeling off the second substrate layer and transferring the liquid crystal retardation layer.

(Alignment Layer (First Alignment Layer, Second Alignment Layer))
The alignment layer has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction.

The alignment layer facilitates the alignment of the polymerizable liquid crystal compound. The state of liquid crystal alignment, such as horizontal alignment, vertical alignment, hybrid alignment, and tilt alignment, varies depending on the properties of the alignment layer and the polymerizable liquid crystal compound, and the combination can be selected arbitrarily. For example, if the alignment layer is a material that exerts horizontal alignment as an alignment control force, the polymerizable liquid crystal compound can form a horizontal alignment or a hybrid alignment, and if the alignment layer is a material that exerts vertical alignment, the polymerizable liquid crystal compound can form a vertical alignment or a tilt alignment. The expressions horizontal, vertical, and the like refer to the direction of the optical axis of the aligned polymerizable liquid crystal compound when the liquid crystal retardation layer plane is used as a reference. For example, vertical alignment means that the optical axis of the aligned polymerizable liquid crystal compound is in a direction perpendicular to the liquid crystal retardation layer plane. The term "vertical" here means 90°±20° relative to the liquid crystal retardation layer plane.

When the alignment layer is made of an alignment polymer, the alignment control force can be adjusted as desired by changing the surface condition and rubbing conditions. When the alignment layer is made of a photoalignment polymer, the alignment control force can be adjusted as desired by changing the polarized light irradiation conditions, etc. In addition, the liquid crystal alignment can be controlled by selecting the physical properties of the polymerizable liquid crystal compound, such as the surface tension and liquid crystallinity.

The alignment layer formed between the base layer and the liquid crystal retardation layer is preferably insoluble in the solvent used to form the liquid crystal retardation layer on the alignment layer, and is heat resistant to the heat treatment for removing the solvent and for aligning the liquid crystal. Examples of the alignment layer include an alignment layer made of an orienting polymer, a photoalignment layer, a groove alignment film, and a stretched film stretched in the alignment direction. When applied to a long rolled film, a photoalignment layer is preferred because the alignment direction can be easily controlled.

The thickness of the alignment layer is usually in the range of 10 nm to 5000 nm, preferably in the range of 10 nm to 1000 nm, and more preferably in the range of 30 to 300 nm.

Examples of the alignment polymers used in the rubbing alignment layer include polyamides and gelatins having amide bonds in the molecule, polyimides having imide bonds in the molecule, and their hydrolyzates such as polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters. Among these, polyvinyl alcohol is preferred. These alignment polymers may be used alone or in combination of two or more.

One method of rubbing is to bring a film of oriented polymer formed on the surface of a substrate layer by applying an oriented polymer composition to the substrate and annealing the composition into contact with a rotating rubbing roll wrapped with a rubbing cloth.

The photo-alignment layer is made of a polymer, oligomer, or monomer having a photoreactive group. The photo-alignment layer can obtain an alignment control force by irradiating it with polarized light. The photo-alignment layer is more preferable in that the direction of the alignment control force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

The photoreactive group is a group that generates liquid crystal alignment ability by irradiation with light. Specifically, it is a group that generates a photoreaction that is the origin of liquid crystal alignment ability, such as molecular alignment induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction, which occurs by irradiation with light. Among the photoreactive groups, those that cause a dimerization reaction or a photocrosslinking reaction are preferred in terms of excellent alignment ability. As photoreactive groups that can generate the above-mentioned reactions, those having an unsaturated bond, especially a double bond, are preferred, and groups having at least one selected from the group consisting of a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond), and a carbon-oxygen double bond (C=O bond) are more preferred.

Examples of photoreactive groups having a C=C bond include vinyl groups, polyene groups, stilbene groups, stilbazolyl groups, stilbazolium groups, chalcone groups, and cinnamoyl groups. From the viewpoint of easy control of reactivity and the expression of alignment control force during photoalignment, chalcone groups and cinnamoyl groups are preferred. Examples of photoreactive groups having a C=N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of photoreactive groups having an N=N bond include azobenzene groups, azonaphthalene groups, aromatic heterocyclic azo groups, bisazo groups, and formazan groups, as well as groups having an azoxybenzene basic structure. Examples of photoreactive groups having a C=O bond include benzophenone groups, coumarin groups, anthraquinone groups, and maleimide groups. These groups may have substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups, and halogenated alkyl groups.

The polarized light can be irradiated directly from the film surface or from the substrate layer side and then transmitted through the film. It is particularly preferable that the polarized light is substantially parallel light. The polarized light to be irradiated should be in a wavelength range in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) in the wavelength range of 250 to 400 nm is particularly preferable. Examples of light sources used for the polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and ultraviolet lasers such as KrF and ArF, with high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps being more preferable. These lamps are preferable because they emit ultraviolet light with a wavelength of 313 nm with a high emission intensity. Polarized light can be irradiated by passing light from the light source through an appropriate polarizer. Examples of such polarizers include polarizing filters, polarizing prisms such as Glan-Thompson and Glan-Taylor, and wire grid type polarizers.

From the viewpoint of easily adjusting the light transmittance Tx of the first liquid crystal retardation layer with the substrate to the above-mentioned range, it is particularly preferable that the first liquid crystal retardation layer does not include a first alignment layer. When the first alignment layer is provided, it is preferable to use a material that has a small absorbance at wavelengths of 280 to 340 nm as the material constituting the first alignment layer.

<Polarizing Plate>
A polarizing plate is a film having an optical absorption anisotropy function, and is generally a film including a polarizing element in which a dichroic dye is uniaxially oriented. In order to uniaxially align a dichroic dye, a polarizer can be prepared from a film that is uniaxially stretched in a state in which iodine or an organic dichroic dye is impregnated in a polymer such as a polyvinyl alcohol (PVA) resin, or a liquid crystal polarizer that is an optically anisotropic layer formed by orienting a dichroic dye and a polymerizable liquid crystal compound. That is, the polarizing function is exhibited by anisotropically absorbing light by the dichroic dye included in the polymer of the stretched polymer or the polymerizable liquid crystal compound.

The polarizing plate includes a polarizing element and may have a polarizing element protective film or layer on one or both sides of the polarizing element.

The polarization performance of the polarizing plate can be measured using a spectrophotometer. For example, the transmittance (T1) in the transmission axis direction (direction perpendicular to the orientation) and the transmittance (T2) in the absorption axis direction (direction of orientation) in the visible light wavelength range of 380 nm to 780 nm can be measured by a double beam method using a device in which a prism polarizer is set in a spectrophotometer. The polarization performance in the visible light range can be calculated as the luminosity-corrected single transmittance (Ty') and luminosity-corrected polarization degree (Py) by calculating the single transmittance and the degree of polarization at each wavelength using the following formulas (Formula 1) and (Formula 2), and further performing luminosity correction using a 2-degree visual field (C light source) according to JIS Z 8701. Similarly, the chromaticity a ^* and b ^* in the L ^* a ^* b ^* (CIE) color system are calculated from the transmittance measured in the same manner using the color matching function of the C light source to obtain the hue of the polarizing plate alone (single hue), the hue when the polarizing plates are arranged in parallel (parallel hue), and the hue when the polarizing plates are arranged perpendicularly (orthogonal hue). The closer the values of ^a* and b ^* are to 0, the more neutral the hue is.
Single-piece transmittance (%)=(T1+T2)/2 (Formula 1)
Polarization degree (%)=(T1−T2)/(T1+T2)×100 (Equation 2)

The luminosity-corrected polarization degree Py of the polarizing plate is usually 80% or more, preferably 90% or more, more preferably 95% or more, even more preferably 98% or more, and particularly preferably 99% or more. If it is 99.9% or more, it can be suitably used in a liquid crystal display. Increasing the luminosity-corrected polarization degree Py of the polarizing plate is advantageous in enhancing the anti-reflection function of the optical laminate. If the luminosity-corrected polarization degree Py is less than 80%, the optical laminate may not be able to perform the anti-reflection function when used as an anti-reflection film.

The greater the luminosity-corrected single transmittance Ty' of the polarizing plate, the greater the clarity of the white display. However, as can be seen from the relationship between (Equation 1) and (Equation 2), if the single transmittance is too high, there is a problem that the degree of polarization decreases. Therefore, it is preferably 30% to 60%, more preferably 35% to 55%, even more preferably 38% to 50%, and even more preferably 40% to 45%. If the luminosity-corrected single transmittance Ty' is too high, the luminosity-corrected polarization degree Py becomes too small, and the anti-reflection function may be insufficient when the optical laminate is used as an anti-reflection film.

(Polarizing element)
As described above, the polarizing element may be a polarizer or a liquid crystal polarizer. The polarizing element is preferably a polarizer.

(Polarizer)
A polarizer, that is, a film obtained by uniaxially stretching a polymer such as a polyvinyl alcohol (PVA)-based resin film impregnated with iodine or an organic dichroic dye, can usually be produced through a process of uniaxially stretching a polyvinyl alcohol-based resin film, a process of dyeing the polyvinyl alcohol-based resin film with a dichroic dye such as iodine to adsorb the dichroic dye, a process of treating the polyvinyl alcohol-based resin film with the adsorbed dichroic dye with a crosslinking agent such as a boric acid-containing aqueous solution, and a process of washing with water after the treatment with the crosslinking agent such as a boric acid-containing aqueous solution. The polarizer may contain a crosslinking agent.

The thickness of the polarizer is usually 30 μm or less, preferably 18 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The thickness is usually 1 μm or more, for example, 5 μm or more.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing with a dichroic dye. When the uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before or during the boric acid treatment. Of course, the uniaxial stretching can be performed in the multiple stages shown here. For the uniaxial stretching, a method of uniaxially stretching in the film transport direction between rolls with different peripheral speeds, a method of uniaxially stretching in the film transport direction using a heated roll, or a method of stretching in the width direction using a tenter can be used. The uniaxial stretching may be performed by dry stretching in the air, or by wet stretching in a state in which the polyvinyl alcohol-based resin film is swollen using a solvent such as water. The stretching ratio is usually 3 to 8 times. In addition, an aqueous solution containing polyvinyl alcohol may be applied to the thermoplastic resin film, followed by drying, and then stretched together with the thermoplastic resin film by the above method.

Dyeing of a polyvinyl alcohol-based resin film with a dichroic dye can be carried out, for example, by immersing the polyvinyl alcohol-based resin film in an aqueous solution containing the dichroic dye. Specific examples of the dichroic dye that can be used include iodine and dichroic organic dyes.

(Method of Manufacturing Polarizer)
A polarizer is usually produced through a step of uniaxially stretching a polyvinyl alcohol-based resin film (hereinafter also referred to as a "PVA-based film"), a step of dyeing the PVA-based film with a dichroic dye to adsorb the dichroic dye, a step of treating the PVA-based film with the dichroic dye-adsorbed thereon with a boric acid-containing aqueous solution to crosslink the film, and a step of washing with water after the crosslinking treatment with the boric acid-containing aqueous solution (hereinafter also referred to as a "boric acid treatment").

The uniaxial stretching of the PVA-based film can be performed before, simultaneously with, or after dyeing with a dichroic dye. When the uniaxial stretching is performed after dyeing, it may be performed before or during the boric acid treatment. Of course, the uniaxial stretching can be performed in multiple stages as shown here. For the uniaxial stretching, a method of uniaxially stretching the film in the film transport direction between rolls with different peripheral speeds, a method of uniaxially stretching the film in the film transport direction using a heated roll, or a method of stretching the film in the width direction using a tenter can be used. The uniaxial stretching can be performed by dry stretching in the air, or by wet stretching in which the PVA-based film is stretched in a swollen state using a solvent such as water. The stretching ratio is usually 3 to 8 times.

Dyeing of a PVA-based film with a dichroic dye can be carried out, for example, by immersing the PVA-based film in an aqueous solution containing the dichroic dye. Specific examples of the dichroic dye that can be used include iodine and dichroic organic dyes. It is preferable to immerse the PVA-based film in water to cause it to swell before the dyeing process.

When iodine is used as the dichroic dye, a method is usually used in which the PVA-based film is immersed in an aqueous solution containing iodine and potassium iodide to dye it. The iodine content in this aqueous solution is usually 0.01 to 1 part by mass per 100 parts by mass of water, and the potassium iodide content is usually 0.5 to 20 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution used for dyeing is usually 20 to 40°C. The immersion time in this aqueous solution (dyeing time) is usually 20 to 1,800 seconds.

On the other hand, when a dichroic organic dye is used as the dichroic pigment, a method is usually adopted in which the PVA-based film is immersed in an aqueous solution containing a water-soluble dichroic organic dye to dye it. The content of the dichroic organic dye in this aqueous solution is usually 0.0001 to 10 parts by mass, and preferably 0.001 to 1 part by mass, per 100 parts by mass of water. This aqueous dye solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous dichroic organic dye solution used for dyeing is usually 20 to 80°C. The immersion time in this aqueous solution (dyeing time) is usually 10 to 1800 seconds.

The boric acid treatment after dyeing with a dichroic dye can be carried out by immersing the dyed PVA-based film in a boric acid-containing aqueous solution. The content of boric acid in the boric acid-containing aqueous solution is usually 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. The content of potassium iodide in the boric acid-containing aqueous solution is usually 0.1 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the boric acid-containing aqueous solution is usually 60 to 1200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50°C or higher, preferably 50 to 85°C, and more preferably 60 to 80°C.

After the boric acid treatment, the PVA-based film is usually washed with water. The washing can be carried out, for example, by immersing the boric acid-treated PVA-based film in water. The temperature of the water used in the washing is usually 5 to 40°C. The immersion time is usually 1 to 120 seconds.

After washing with water, a drying process is performed to obtain a polarizer. The drying process can be performed using a hot air dryer or a far-infrared heater. The temperature of the drying process is usually 30 to 100°C, preferably 50 to 80°C. The time of the drying process is usually 60 to 600 seconds, preferably 120 to 600 seconds. The moisture content in the polarizer is reduced to a practical level by the drying process. The moisture content is usually 5 to 20% by mass, preferably 8 to 15% by mass, based on the total mass of the polarizer. If the moisture content is 5% by mass or more, the polarizer has sufficient flexibility, and therefore damage or breakage after drying can be suppressed. Furthermore, if the moisture content is 20% by mass or less, the polarizer has sufficient thermal stability.

In this way, a polarizer can be produced in which a dichroic dye is adsorbed and oriented on a PVA-based film.

The polarizer obtained above can be further laminated with a polarizing element protective film or protective layer on one or both sides to produce a polarizing plate.

(Liquid Crystal Polarizer)
A liquid crystal polarizer, i.e., an optically anisotropic layer made of a polymer of a polymerizable liquid crystal compound containing a dichroic dye, can be suitably used for, for example, flexible display applications because the hue can be arbitrarily controlled, the thickness can be significantly reduced, and the layer is non-shrinkable since it is not stretched or relaxed by heat.

The liquid crystal polarizer is formed by applying a liquid crystal polarizer-forming composition onto the third substrate layer or onto the third alignment layer formed on the third substrate layer, and orienting the dichroic dye contained in the liquid crystal polarizer-forming composition. The thickness of the liquid crystal polarizer is preferably 0.1 μm or more and 5 μm or less, more preferably 0.3 μm or more and 4 μm or less, and even more preferably 0.5 μm or more and 3 μm or less. If the thickness is smaller than the above range, the necessary light absorption may not be obtained, and if the thickness is larger than the above range, the alignment control force by the third alignment layer decreases, and alignment defects tend to occur easily. In addition, the liquid crystal polarizer-forming composition may further contain a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, an adhesion improver, etc.

In a liquid crystal polarizer in which the dichroic dye and polymerizable liquid crystal compound are aligned horizontally relative to the surface of the third substrate layer, the ratio (dichroic ratio) of the absorbance A1 (λ) in the alignment direction for light with a wavelength of λ nm to the absorbance A2 (λ) in the vertical direction within the alignment plane is preferably 7 or more, more preferably 20 or more, and even more preferably 40 or more. The higher the value of this ratio, the more excellent the absorption selectivity of the liquid crystal polarizer. Depending on the type of dichroic dye, when the polymerizable liquid crystal compound that constitutes the liquid crystal polarizer is cured in a nematic liquid crystal phase state, the above ratio is about 5 to 10.

By mixing two or more dichroic dyes with different absorption wavelengths, it is possible to produce liquid crystal polarizers of various hues, and liquid crystal polarizers that absorb light across the entire visible light range can be produced. By producing liquid crystal polarizers with such absorption characteristics, they can be used in a variety of applications.

(Polymerizable Liquid Crystal Compound Constituting Liquid Crystal Polarizer)
The polymerizable liquid crystal compound is a compound having a polymerizable group and liquid crystallinity. The polymerizable group means a group involved in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group means a group that can be involved in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described later. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferred, and a methacryloyloxy group or an acryloyloxy group is more preferred. The liquid crystallinity may be thermotropic liquid crystal or lyotropic liquid crystal, but when mixed with a dichroic dye described later, a thermotropic liquid crystal is preferred. The polymerizable liquid crystal compound may be a monomer, or may be a polymer polymerized to form a dimer or more.

When the polymerizable liquid crystal compound is a thermotropic liquid crystal, it may be a thermotropic liquid crystal compound exhibiting a nematic liquid crystal phase, or a thermotropic liquid crystal compound exhibiting a smectic liquid crystal phase. From the viewpoint of being able to exhibit high dichroism, the liquid crystal state exhibited by the polymerizable liquid crystal compound is preferably a smectic phase, and a high-order smectic phase is more preferable from the viewpoint of improving performance. Among them, a high-order smectic polymerizable liquid crystal compound that forms a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, or a smectic L phase is more preferable, and a high-order smectic polymerizable liquid crystal compound that forms a smectic B phase, a smectic F phase, or a smectic I phase is even more preferable. When the liquid crystal phase formed by the polymerizable liquid crystal compound is one of these high-order smectic phases, a liquid crystal polarizer with higher polarization performance can be manufactured. Furthermore, such liquid crystal polarizers with high polarization performance are capable of obtaining Bragg peaks derived from higher-order structures such as hexatic and crystalline phases in X-ray diffraction measurements. The Bragg peaks are peaks derived from the periodic structure of molecular orientation, and a film with a periodic interval of 3 to 6 Å can be obtained. It is preferable for the liquid crystal polarizer to contain a polymer of the polymerizable liquid crystal compound oriented in a smectic phase, from the viewpoint of obtaining higher polarization characteristics.

The polymerizable liquid crystal compound may be used alone or in combination of two or more. The composition for forming a liquid crystal polarizer containing other compounds described later may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound as long as the effect of the present invention is not impaired. From the viewpoint of obtaining a liquid crystal polarizer with a high degree of orientation order, the ratio of the polymerizable liquid crystal compound (polymerizable liquid crystal compound other than other polymerizable liquid crystal compounds) to the total mass of all polymerizable liquid crystal compounds contained in the composition for forming a liquid crystal polarizer is preferably 51% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

The content of the polymerizable liquid crystal compound in the composition for forming a liquid crystal polarizer is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and even more preferably 70 to 99% by mass, based on the solid content of the polymerizable liquid crystal composition. When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be high. In this specification, the solid content refers to the total amount of components excluding the solvent from the composition for forming a liquid crystal polarizer.

(Dichroic dyes constituting liquid crystal polarizers)
A dichroic dye refers to a dye having different absorbance in the long axis direction of the molecule and absorbance in the short axis direction. As a dichroic dye, a dye having a property of absorbing visible light is preferable, and a dye having a maximum absorption wavelength (λMAX) in the wavelength range of 380 to 680 nm is more preferable. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes, and among them, azo dyes are preferable. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, and the like, and bisazo dyes and trisazo dyes are preferable. The dichroic dyes may be used alone or in combination, but in order to obtain absorption over the entire visible light range, it is preferable to combine two or more dichroic dyes, and more preferably to combine three or more dichroic dyes.

An example of the azo dye is a compound represented by formula (VIII) (hereinafter, sometimes referred to as "compound (VIII)").
T ¹ -A ¹ (-N=NA ² ) _p -N=NA ³ -T ² (VIII)
[In formula (VIII),
A ¹ , A ² , and A ³ each independently represent a 1,4-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, a benzoic acid phenyl ester group which may have a substituent, a 4,4′-stilbenylene group which may have a substituent, or a divalent heterocyclic group which may have a substituent.
^T1 and ^T2 are, independently of each other, electron withdrawing or electron releasing groups and are oriented at substantially 180° to the plane of the azo bond.
p represents an integer of 0 to 4. When p is 2 or more, each ^A2 may be the same or different. The -N=N- bond may be replaced with a -C=C-, -COO-, -NHCO-, or -N=CH- bond as long as the compound exhibits absorption in the visible range.]

The content of the dichroic dye (the total amount when multiple types are included) is usually 1 to 60 parts by mass, preferably 1 to 40 parts by mass, and more preferably 1 to 20 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound, from the viewpoint of obtaining good light absorption characteristics. If the content of the dichroic dye is less than this range, light absorption will be insufficient and sufficient polarization performance will not be obtained, and if the content is more than this range, the alignment of the liquid crystal molecules may be hindered.

The liquid crystal polarizer can be manufactured by applying a liquid crystal polarizer-forming composition onto the third substrate layer or onto the third alignment layer formed on the third substrate layer. The liquid crystal polarizer-forming composition may further contain additives such as a solvent, a leveling agent, a polymerization initiator, a photosensitizer, an antioxidant, a crosslinking agent, an adhesive agent, and other reactive additives, and it is preferable from the viewpoint of processability that the composition contains a solvent and a leveling agent. As these additives, those described in the liquid crystal retardation layer-forming composition can be used.

Examples of the method for applying the composition for forming a liquid crystal polarizer, the method for drying the composition for forming a liquid crystal polarizer to remove the solvent contained therein, and the method for polymerizing the polymerizable liquid crystal compound contained in the composition for forming a liquid crystal polarizer include the methods described in the method for manufacturing a liquid crystal retardation layer. Examples of the third substrate layer and the third alignment layer include the first substrate layer and the second substrate layer described in the method for manufacturing a liquid crystal retardation layer, and the first alignment layer and the second alignment layer described in the method for manufacturing a liquid crystal retardation layer.

A polarizing plate can be manufactured by laminating a polarizing element protective film or protective layer on one or both sides of a liquid crystal polarizer.

(Polarizing element protective film)
The polarizing element protective film has a function of protecting the surface of the polarizing element. The polarizing element and the polarizing element protective film may be directly laminated to each other. Here, "directly laminated" includes an embodiment in which the polarizing element protective film is laminated to the polarizing element by the self-adhesiveness of the polarizing element protective film, and an embodiment in which the polarizing element protective film is laminated via a pressure-sensitive adhesive layer (adhesive layer or pressure-sensitive adhesive layer). The polarizing element protective film may be subjected to a surface treatment (e.g., corona treatment, etc.) to improve adhesion to the polarizing element, and a thin layer such as a primer layer (also called an "easy adhesion layer") may be formed.

As the polarizing element protective film, for example, a resin film having excellent transparency, mechanical strength, thermal stability, moisture blocking properties, isotropy, stretchability, etc. can be used. The resin film may be a thermoplastic resin film. Specific examples of resins constituting such a resin film include cellulose-based resins such as triacetyl cellulose; polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone-based resins; polysulfone-based resins; polycarbonate-based resins; polyamide-based resins such as nylon and aromatic polyamide; polyimide-based resins; polyolefin-based resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; cyclic polyolefin-based resins having cyclo- and norbornene structures (also called "norbornene-based resins"); (meth)acrylic resins such as polymethyl methacrylate; polyarylate-based resins; polystyrene-based resins; polyvinyl alcohol-based resins, and mixtures thereof. Polarizing element protective films made of such materials are easily available on the market. Other examples include thermosetting resins or ultraviolet-curing resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone. In this specification, (meth)acrylic means either acrylic or methacrylic. The same applies to the notations (meth)acrylate and (meth)acryloyl.

Examples of linear polyolefin resins include linear olefin homopolymers such as polyethylene resins (polyethylene resins which are homopolymers of ethylene, and copolymers mainly composed of ethylene) and polypropylene resins (polypropylene resins which are homopolymers of propylene, and copolymers mainly composed of propylene), as well as copolymers made of two or more linear olefins.

Cyclic polyolefin resin is a general term for resins polymerized using cyclic olefins as polymerization units, and examples of such resins include those described in JP-A-1-240517, JP-A-3-14882, and JP-A-3-122137. Specific examples of cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers (typically random copolymers) of cyclic olefins with linear olefins such as ethylene and propylene, and graft polymers modified with unsaturated carboxylic acids or their derivatives, as well as hydrogenated products thereof. Of these, norbornene resins using norbornene monomers such as norbornene or polycyclic norbornene monomers as the cyclic olefin are preferably used.

Polyester resins are resins with ester bonds in the main chain, and are generally polycondensates of polycarboxylic acids or their derivatives with polyhydric alcohols. As polycarboxylic acids or their derivatives, divalent dicarboxylic acids or their derivatives can be used, such as terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. As polyhydric alcohols, divalent diols can be used, such as ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. A representative example of polyester resins is polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol.

Cellulose ester resins are esters of cellulose and fatty acids. Specific examples of cellulose ester resins include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Other examples include copolymers having multiple types of polymerization units constituting these cellulose ester resins, and resins in which some of the hydroxyl groups have been modified with other substituents. Among these, cellulose triacetate (triacetyl cellulose) is particularly preferred.

The (meth)acrylic resin is a resin whose main constituent monomer is a compound having a (meth)acryloyl group. Specific examples of the (meth)acrylic resin include poly(meth)acrylic acid ester such as polymethyl methacrylate; methyl methacrylate-(meth)acrylic acid copolymer; methyl methacrylate-(meth)acrylic acid ester copolymer; methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymer; methyl (meth)acrylate-styrene copolymer (MS resin, etc.); and copolymers of methyl methacrylate and compounds having alicyclic hydrocarbon groups (e.g. methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth)acrylate copolymer, etc.). Preferably, a polymer whose main component is a poly(meth)acrylic acid C _1-6 alkyl ester such as polymethyl (meth)acrylate is used, and more preferably, a methyl methacrylate resin whose main component is methyl methacrylate (50 to 100% by weight, preferably 70 to 100% by weight) is used.

Polycarbonate-based resins consist of polymers in which monomer units are bonded via carbonate groups. The polycarbonate-based resin may be a resin called a modified polycarbonate, in which the polymer backbone has been modified, or a copolymer polycarbonate. Examples of polycarbonate-based resins include those described in JP 2012-31370 A.

The thickness of the polarizing element protective film is preferably 0.1 μm to 60 μm, more preferably 0.5 μm to 40 μm, and even more preferably 1 μm to 30 μm.

The polarizing element protective film can be used by being disposed so as to be on the viewing side of the polarizing element. Therefore, the polarizing element protective film may be subjected to surface treatments such as hard coat treatment, anti-reflection treatment, anti-sticking treatment, and anti-glare treatment, as necessary. Furthermore, the polarizing element protective film may be subjected to treatments (typically, imparting an (elliptical) polarization function, imparting an ultra-high phase difference) to improve visibility when viewed through polarized sunglasses, as necessary. By performing such treatments, excellent visibility can be achieved even when the display screen is viewed through polarized lenses such as polarized sunglasses. Therefore, a polarizing plate equipped with a polarizing element protective film having a phase difference can be suitably applied to image display devices that can be used outdoors.

A polarizing element protective film can be produced by stretching a film containing the above thermoplastic resin. Examples of stretching treatment include uniaxial stretching and biaxial stretching. Examples of stretching directions include the machine flow direction (MD) of the unstretched film, a direction perpendicular to the MD (TD), and a direction oblique to the machine flow direction (MD). Biaxial stretching may be simultaneous biaxial stretching in which the film is stretched in two stretching directions at the same time, or sequential biaxial stretching in which the film is stretched in a predetermined direction and then stretched in the other direction. The stretching treatment can be performed, for example, by using two or more pairs of nip rolls with a high peripheral speed on the outlet side to stretch the film in the longitudinal direction (machine flow direction: MD), or by gripping both side ends of the unstretched film with chucks to spread it in the direction perpendicular to the machine flow direction (TD). At this time, the retardation value and wavelength dispersion can be controlled by adjusting the thickness of the film or the stretching ratio. In addition, the wavelength dispersion value can be controlled by adding a wavelength dispersion adjuster to the resin.

The polarizing element protective film may contain any suitable additive depending on the purpose. Examples of additives include antioxidants such as hindered phenols, phosphorus, and sulfur, stabilizers such as light stabilizers, ultraviolet absorbers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fibers and carbon fibers; near-infrared absorbers; flame retardants such as tris(dibromopropyl)phosphate, triallyl phosphate, and antimony oxide; antistatic agents such as anionic, cationic, and nonionic surfactants; colorants such as inorganic pigments, organic pigments, and dyes; organic and inorganic fillers; resin modifiers; plasticizers; lubricants; retardation reducers, and the like. The types, combinations, and amounts of additives contained may be appropriately set depending on the purpose and desired characteristics.

In order to impart desired surface optical properties or other characteristics, a coating layer (surface treatment layer) can be provided on the outer surface of the polarizing element protective film. Specific examples of the surface treatment layer include a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer. There are no particular limitations on the method for forming the surface treatment layer, and known methods can be used. The surface treatment layer may be formed on one surface or both surfaces of the polarizing element protective film.

The hard coat layer has the function of increasing the surface hardness of the polarizing element protective film, and is provided for the purpose of preventing surface scratches, etc. It is preferable that the hard coat layer has a pencil hardness of H or harder as measured by the pencil hardness test (measured by placing an optical film having a hard coat layer on a glass plate) specified in JIS K 5600-5-4:1999 "General test methods for paints - Part 5: Mechanical properties of coatings - Section 4: Scratch hardness (pencil method)"

The material that forms the hard coat layer is generally cured by heat or light. Examples include organic hard coat materials such as organic silicone-based, melamine-based, epoxy-based, (meth)acrylic-based, and urethane (meth)acrylate-based, and inorganic hard coat materials such as silicon dioxide. Among these, urethane (meth)acrylate-based or multifunctional (meth)acrylate-based hard coat materials are preferably used because they have good adhesion to the polarizing element protective film and are highly productive.

The hard coat layer may contain various fillers as desired to adjust the refractive index, improve the flexural modulus, stabilize the volumetric shrinkage rate, and further improve heat resistance, antistatic properties, antiglare properties, etc. The hard coat layer may also contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, leveling agents, and defoamers.

The hard coat layer may contain additives to further improve its strength. The additives are not limited, and examples include inorganic fine particles, organic fine particles, and mixtures thereof. The thickness of the hard coat layer is preferably thicker in order to provide hardness, but if it is too thick, it will be prone to cracking when cut, so the thickness is, for example, 1 μm to 20 μm, and may be 2 μm to 10 μm. The thickness of the hard coat layer is preferably 3 μm to 7 μm.

The antiglare layer is a layer having a finely uneven surface, and is preferably formed using the material for forming the hard coat layer described above.

An anti-glare layer having a finely uneven surface can be formed by 1) forming a coating film containing fine particles on a stretched film and providing the uneven surface based on the fine particles, or 2) forming a coating film, which may or may not contain fine particles, on a stretched film, and then pressing the film against a mold (such as a roll) that has been given an uneven surface to transfer the uneven surface (also called an embossing method).

The anti-reflection layer is a layer that weakens the reflection of external light on the surface of the polarizing element protective film for a person observing the polarizing element protective film, and typically has a reflectance of 1.5% or less for visible light. An anti-reflection layer with such reflectance can typically be obtained by laminating a high refractive index layer having a high refractive index and a low refractive index layer having a low refractive index, or by using the method and materials described in JP 2021-6929 A. By adjusting these refractive indices and the thickness of each layer, the reflected light from each layer can be weakened by each other, providing excellent anti-reflection functionality.

It is preferable to manufacture the anti-reflection layer consisting of a high refractive index layer and a low refractive index layer using a coating composition capable of forming each of the high refractive index layer and the low refractive index layer, since the operation is extremely simple. Here, an example of a coating composition capable of forming each of the high refractive index layer and the low refractive index layer will be given. Such a coating composition is liquid and contains an appropriate curable resin and, if necessary, an additive. A coating composition capable of forming a high refractive index layer (a composition for forming a high refractive index layer) is, for example, a curable resin such as urethane acrylate, and an initiator for photopolymerization (photopolymerization initiator) such as an acetophenone type, a benzophenone type, a benzyl dimethyl ketal type, an α-hydroxyalkylphenone type, an α-aminoalkylphenone type, or a thioxanthone type, dissolved in a solvent such as methyl ethyl ketone or methyl isobutyl ketone. In order to improve the coating property, a leveling agent, preferably a fluorine-based leveling agent, may be included. In addition, the coating composition capable of forming a low refractive index layer (composition for forming a low refractive index layer) is a binder resin such as polyethylene glycol diacrylate or pentaerythritol (tri/tetra)acrylate as a curable resin, and a photopolymerization initiator (photopolymerization initiator) such as acetophenone, benzophenone, benzyl dimethyl ketal, α-hydroxyalkylphenone, α-aminoalkylphenone, or thioxanthone is dissolved in a solvent such as 1-methoxy-2-propyl acetate or methyl isobutyl, and silica particles are dispersed in the solution. In order to improve the coating properties, a fluorine-based leveling agent may be contained. Note that the coating compositions capable of forming the high refractive index layer and the low refractive index layer listed here are merely examples, and it is preferable to optimize the composition for forming the high refractive index layer and the composition for forming the low refractive index layer, respectively, depending on the characteristics of the antireflection layer to be formed.

The antireflection layer may, for example, include a low refractive index layer. It may also have a multi-layer structure further including a high refractive index layer and/or a medium refractive index layer between the polarizing element protective film and the low refractive index layer.

The low refractive index layer can be formed by applying a coating liquid containing a cured product of the above-mentioned curable resin or a light-transmitting resin such as a metal alkoxide polymer and inorganic particles, and then curing the coating layer as necessary. Examples of inorganic particles include low refractive index particles such as LiF (refractive index 1.4), MgF (refractive index 1.4), 3NaF·AlF (refractive index 1.4), AlF (refractive index 1.4), Na ₃ AlF ₆ (refractive index 1.33), and hollow silica particles.

The antistatic layer is provided for the purpose of imparting electrical conductivity to the surface of the polarizing element protective film and suppressing the effects of static electricity. For example, the antistatic layer can be formed by applying a resin composition containing a conductive substance (antistatic agent) onto the polarizing element protective film. For example, an antistatic hard coat layer can be formed by adding an antistatic agent to the material for forming the hard coat layer described above.

The antifouling layer is provided to provide water repellency, oil repellency, sweat resistance, antifouling properties, etc. A suitable material for forming the antifouling layer is a fluorine-containing organic compound. Examples of fluorine-containing organic compounds include fluorocarbons, perfluorosilanes, and polymeric compounds thereof. The method for forming the antifouling layer can be a physical vapor deposition method, typically vapor deposition or sputtering, a chemical vapor deposition method, a wet coating method, or the like, depending on the material to be formed. The average thickness of the antifouling layer is usually about 1 to 50 nm, and preferably 3 to 35 nm.

(Protective Layer)
The polarizing plate may have a protective layer on one or both sides of the polarizing element. When a liquid crystal polarizer is used as the polarizing element and the liquid crystal polarizer is laminated with another film by adhesion with a pressure-sensitive adhesive or the like, by providing a protective layer on the surface of the liquid crystal polarizer, it is possible to prevent low-molecular components such as unreacted polymerizable liquid crystal compounds and dichroic dyes in the liquid crystal polarizer from diffusing into another layer.

The protective layer is preferably thin if it can prevent low molecular weight components such as unreacted polymerizable liquid crystal compounds and dichroic dyes in the liquid crystal polarizer from diffusing into other layers. The thickness of the protective layer is preferably 0.1 μm or more and 10 μm or less, more preferably 0.1 μm or more and 5 μm or less, and even more preferably 0.1 μm or more and 3 μm or less.

The protective layer is preferably a polymer with a high crosslink density or a water-soluble polymer with high hydrophilic interaction. For example, it contains at least one selected from the group consisting of (meth)acrylic resin, epoxy resin, oxetane resin, urethane resin, melamine resin, and polyvinyl alcohol resin. Among these, from the viewpoint of excellent curability and ease of formation, it is preferable to contain at least one selected from the group consisting of (meth)acrylic resin, epoxy resin, oxetane resin, urethane resin, and melamine resin, and it is more preferable to contain at least one selected from the group consisting of (meth)acrylic resin and urethane resin. Also, from the viewpoint of hydrophilicity, polyvinyl alcohol resin is preferable.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" and "parts" in the examples and comparative examples mean "% by mass" and "parts by mass", respectively.

<Preparation of Polarizing Plate a>
(Preparation of Polarizer a)
A polyvinyl alcohol film having an average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol% or more, and a thickness of 75 μm was immersed in pure water at 30° C., and then immersed in an aqueous solution having an iodine/potassium iodide/water ratio of 0.02/2/100 at 30° C. to perform iodine dyeing (dyeing step). The polyvinyl alcohol film that had been subjected to the dyeing step was immersed in an aqueous solution having a potassium iodide/boric acid/water ratio of 12/5/100 at 56.5° C. to perform boric acid treatment (boric acid treatment step).

The polyvinyl alcohol film that had been through the boric acid treatment process was washed with pure water at 8°C and then dried at 65°C to obtain polarizer a in which iodine was adsorbed and oriented in the polyvinyl alcohol. At this time, stretching was performed in the iodine dyeing process and the boric acid treatment process. The total stretching ratio in this stretching was 5.3 times, and the thickness of the obtained polarizer a was 27 μm.

(Preparation of Polarizing Plate a)
A cyclic polyolefin resin (COP) film (ZEON Corporation, Zeonor ZF14, thickness 13 μm) was attached to one side of the polarizer a as a polarizing element protective film via a water-based adhesive, and a saponified triacetyl cellulose film (product name: KC4UYTAC, Konica Minolta, thickness 40 μm) was attached to the other side of the polarizer a via a water-based adhesive. The resulting laminate was dried at 60° C. for 2 minutes while maintaining the tension of 430 N/m to obtain a polarizing plate a. The water-based adhesive was prepared by adding 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318, Kuraray) and 1.5 parts of water-soluble polyamide epoxy resin (Sumirez Resin 650, Sumika Chemtex, aqueous solution with a solid content of 30%) to 100 parts of water.

<Preparation of Polarizing Plate (b)>
A saponified triacetyl cellulose film (product name: KC4UYTAC, manufactured by Konica Minolta, thickness 40 μm) was attached to both sides of the polarizer a via the aqueous adhesive used in the preparation of the polarizing plate a. The resulting laminate was dried at 60° C. for 2 minutes while maintaining the tension at 430 N/m, to obtain a polarizing plate b having triacetyl cellulose (TAC) films as polarizing element protective films on both sides.

<Preparation of first liquid crystal retardation layer (1)>
(Preparation of first liquid crystal retardation layer forming composition (1))
0.1 parts of a leveling agent "BYK-361N" (manufactured by BYK-Chemie) and 2.5 parts of a photopolymerization initiator "Omnirad907" (manufactured by IGM Resin B.V.) were added to 100 parts of the polymerizable liquid crystal compound Paliocolor LC242 (manufactured by BASF Japan) shown below. Furthermore, 400 parts of propylene glycol 1-monomethyl ether 2-acetate (PGME) were added to 100 parts of the polymerizable liquid crystal compound, and the mixture was stirred at a temperature of 80° C. for 1 hour to prepare a first liquid crystal retardation layer forming composition (1).

Polymerizable liquid crystal compound Paliocolor LC242:

(Preparation of the first liquid crystal retardation layer (1) with substrate)
A rectangular cut triacetyl cellulose (TAC) film (Konica Minolta, Inc., KC4UY (thickness 40 μm)) was rubbed at an angle of 15° from the longitudinal direction of the TAC film as the first base layer (1), and the first liquid crystal retardation layer forming composition (1) was applied thereon by a bar coater. The obtained coating layer was dried at 100° C. for 1 minute, and then cooled to room temperature to obtain a dry coating. Next, the dried film was irradiated with ultraviolet light of 1000 mJ/cm ² (based on 365 nm) using a high-pressure mercury lamp ("Uniqure VB-15201BY-A" manufactured by Ushio Inc.) under a nitrogen atmosphere to form a first polymer layer (1) (horizontally aligned liquid crystal cured film) in which the polymerizable liquid crystal compound was cured in a state where it was aligned horizontally relative to the plane of the first base layer (1), thereby obtaining a first liquid crystal retardation layer (1) with a base material consisting of the first base layer (1)/first liquid crystal retardation layer (1) (first polymer layer (1)).

The thickness of the obtained first polymer layer (1) was measured with a laser microscope and found to be 1.0 μm. The in-plane retardation value of the substrate-attached first liquid crystal retardation layer (1) was measured using KOBRA-WR manufactured by Oji Scientific Instruments. As a result, the in-plane retardation value at a wavelength of 550 nm was Re(550)=140 nm. Note that the retardation value at a wavelength of 550 nm of the TAC film, which is the first substrate layer (1), is approximately 0, so there is no effect on the optical characteristics. The orientation angle was 15° with respect to the longitudinal direction of the first substrate layer (1). The first liquid crystal retardation layer (1) had positive wavelength dispersion.

<Preparation of first liquid crystal retardation layer (2)>
(Preparation of the first liquid crystal retardation layer (2) with substrate)
The first liquid crystal retardation layer (2) was formed on the first base material layer (1) described in the preparation of the first liquid crystal retardation layer (1) with a substrate by the procedure for preparing the third optically anisotropic layer described in paragraphs [0136] and [0137] of WO 2021/060378, to obtain a first liquid crystal retardation layer (2) with a substrate consisting of the first base material layer (1)/first liquid crystal retardation layer (2) (first polymer layer (2)).

<Preparation of the first liquid crystal retardation layer (3)>
(Preparation of Vertical Alignment Layer Forming Composition (1) (Alignment Layer Forming Composition))
As the composition (1) for forming the vertical alignment layer, a mixture was used in which 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate, and bis(2-vinyloxyethyl) ether were mixed in a ratio of 1:1:4:5, and LUCIRIN TPO was added as a polymerization initiator in a ratio of 4%.

(Preparation of first liquid crystal retardation layer forming composition (2))
The first liquid crystal retardation layer forming composition (2) was prepared by preparing a photopolymerizable nematic liquid crystal compound (RMM28B, manufactured by Merck) and a solvent so that the solid content was 1 to 1.5 g. The solvent used was a mixed solvent in which methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) were mixed in a mass ratio (MEK:MIBK:CHN) of 35:30:35.

(Preparation of the first liquid crystal retardation layer (3) with substrate)
A polyethylene terephthalate (PET) film having a thickness of 38 μm was prepared as the first base layer (2). The composition for forming a vertical alignment layer (1) was applied to one side of the first base layer (2) to a thickness of 3 μm, and irradiated with ultraviolet light of 200 mJ/ ^cm2 to prepare the first alignment layer (1) as a vertical alignment layer.

The first liquid crystal retardation layer forming composition (2) was applied onto the first alignment layer (1) by die coating. The amount of coating was 4 to 5 g (wet). The coating was dried at a drying temperature of 75°C for a drying time of 120 seconds. The coating was then irradiated with ultraviolet (UV) rays to polymerize the polymerizable liquid crystal compound and form a first polymer layer (3), thereby obtaining a first liquid crystal retardation layer (3) with a substrate consisting of the first substrate layer (2)/first liquid crystal retardation layer (3) (first alignment layer (1)/first polymer layer (3)).

The first liquid crystal retardation layer (3) with the substrate was a positive C plate. The thickness of the first liquid crystal retardation layer (3) was 4 μm. After the first liquid crystal retardation layer (3) with the substrate was attached to glass via an adhesive, the first substrate layer (3) was peeled off, and the in-plane retardation value of the first liquid crystal retardation layer (3) was measured. For the measurement, a "KOBRA-WPR" manufactured by Oji Scientific Instruments Co., Ltd. was used. The in-plane retardation value at a wavelength of 550 nm was Re(550) = 1 nm, and the retardation value in the thickness direction at a wavelength of 550 nm was Rth(550) = -100 nm. The first liquid crystal retardation layer (3) had positive wavelength dispersion.

<Preparation of first liquid crystal retardation layer (c1)>
(Preparation of Orientable Polymer Composition (c1) (Orientation Layer Forming Composition (c1)))
Water was added to commercially available polyvinyl alcohol (polyvinyl alcohol 1000 fully saponified type, manufactured by Wako Pure Chemical Industries, Ltd.), and the mixture was heated at 100° C. for 1 hour to obtain an oriented polymer composition (c1).

(Preparation of the first liquid crystal retardation layer (c1) with substrate)
The oriented polymer composition (c1) was applied to a rectangular cut triacetyl cellulose (TAC) film (Konica Minolta, Inc., KC8UY (thickness 80 μm)) as the first base layer (c1), and the oriented polymer composition (c1) was heated and dried to form a first alignment layer (c1) having a thickness of 100 nm. The surface of the first alignment layer (c1) was subjected to a rubbing treatment at an angle of 15° from the longitudinal direction of the TAC film, and the first liquid crystal retardation layer forming composition (1) was applied thereon by a bar coater. The obtained coating layer was dried at 100 ° C. for 1 minute, and then cooled to room temperature to obtain a dried coating. Next, the dried film was irradiated with ultraviolet light of 1000 mJ/cm ² (based on 365 nm) using a high-pressure mercury lamp ("Unicure VB-15201BY-A" manufactured by Ushio Inc.) under a nitrogen atmosphere to form a first polymer layer (c1) (horizontally aligned liquid crystal cured film) in which the polymerizable liquid crystal compound was cured in a state where it was aligned horizontally relative to the plane of the first base layer (c1), thereby obtaining a first liquid crystal retardation layer (c1) with base consisting of the first base layer (c1)/first liquid crystal retardation layer (c1) (first alignment layer (c1)/first polymer layer (c1)).

The thickness of the obtained first polymer layer (c1) was measured with a laser microscope and found to be 1.0 μm. The in-plane retardation value of the substrate-attached first liquid crystal retardation layer (c1) was measured using KOBRA-WR manufactured by Oji Scientific Instruments. As a result, the in-plane retardation value at a wavelength of 550 nm was Re(550)=140 nm. Note that the retardation value at a wavelength of 550 nm of the TAC film, which is the first substrate layer (c1), is approximately 0, so there is no effect on the optical properties. The orientation angle was 15° with respect to the longitudinal direction of the first substrate layer (c1). The first liquid crystal retardation layer (c1) had positive wavelength dispersion.

[Measurement of light transmittance Tx of first liquid crystal retardation layer with substrate]
The light transmittance Tx of the first liquid crystal retardation layer with the substrate obtained above at a wavelength of 317 nm was measured using an ultraviolet-visible spectrophotometer (Shimadzu Corporation's "UV-2450"). The results are shown in Tables 1 to 3.

[Measurement of thickness of first base layer]
The thickness of the first base layer was measured using a contact type thickness meter (Nikon: Digimicro MH-15M). The results are shown in Tables 1 to 3.

<Preparation of second liquid crystal retardation layer (1)>
(Preparation of second liquid crystal retardation layer forming composition (1))
Polymerizable liquid crystal compound (A1) and polymerizable liquid crystal compound (A2) having the structures shown below were prepared according to the method described in JP-A-2010-244038.

重合性液晶化合物（Ａ２）：

Polymerizable liquid crystal compound (A1):

Polymerizable liquid crystal compound (A2):

The polymerizable liquid crystal compound (A1) and the polymerizable liquid crystal compound (A2) were mixed in a mass ratio of 80:20 to obtain a mixture. 0.1 parts of a leveling agent "Megafac F-556" (manufactured by DIC Corporation), 2.5 parts of a photopolymerization initiator "Omnirad 907" (manufactured by IGM Resin B.V.), and 0.1 parts of an ionic compound (B) shown below were added to 100 parts of the obtained mixture. Furthermore, 650 parts of cyclopentanone were added to 100 parts of the mixture, and the mixture was stirred at a temperature of 80°C for 1 hour to prepare a second liquid crystal retardation layer forming composition (1).

Ionic Compound (B)

(Preparation of second liquid crystal retardation layer (1) with substrate)
A rectangular cut cycloolefin polymer (COP) film (ZF14, 13 μm thick, manufactured by Zeon Corporation) was subjected to corona treatment using a corona treatment device (AGF-B10; manufactured by Kasuga Electric Co., Ltd.) as the second base layer (1), and then an oriented polymer composition (c1) was applied thereto. After drying by heating, a second orientation layer (1) of an oriented polymer having a thickness of 100 nm was formed. The surface of the second orientation layer (1) was subjected to rubbing treatment at an angle of 75° from the longitudinal direction of the COP film, and the second liquid crystal retardation layer forming composition (1) was applied thereon using a bar coater and dried at 120° C. for 2 minutes to obtain a dried coating. Using a high-pressure mercury lamp ("Uniqure VB-15201BY-A" manufactured by Ushio Inc.), the dried film was irradiated with ultraviolet light at an exposure dose of 1000 mJ/cm ² (based on 365 nm) at a temperature of 80° C. under a nitrogen atmosphere to form a second polymer layer (1) in which the optical axis of the polymerizable liquid crystal compound was aligned horizontally relative to the plane of the second substrate layer (1) and cured, thereby obtaining a substrate-attached second liquid crystal retardation layer (1) as an optical film. The substrate-attached second liquid crystal retardation layer (1) has a layer structure of second substrate layer (1)/second liquid crystal retardation layer (1) (second alignment layer (1)/second polymer layer (1)).

The thickness of the obtained second polymer layer (1) was measured with a laser microscope and found to be 1.8 μm. The in-plane retardation value of the second liquid crystal retardation layer (1) with the substrate was measured using KOBRA-WR manufactured by Oji Scientific Instruments. As a result, the in-plane retardation value at a wavelength of 550 nm was Re(550)=270 nm. Note that the retardation value of the COP film, which is the second substrate layer (1), at a wavelength of 550 nm is approximately 0, so there is no effect on the optical properties of the second liquid crystal retardation layer (1) with the substrate. The orientation angle was 75° with respect to the longitudinal direction of the second substrate layer (1). The second liquid crystal retardation layer (1) had positive wavelength dispersion.

<Preparation of second liquid crystal retardation layer (2)>
(Preparation of composition for forming photo-alignment film (2) (composition for forming alignment layer))
The photo-alignment material (weight average molecular weight: 50,000, m:n = 50:50) having the following structure was produced according to the method described in JP 2021-196514 A. The photo-alignment film-forming composition (2) was prepared by mixing 2 parts of the photo-alignment material and 98 parts of cyclopentanone (solvent) as components and stirring the resulting mixture at 80 ° C. for 1 hour.
Photo-alignable materials:

(Preparation of second liquid crystal retardation layer forming composition (2))
Polymerizable liquid crystal compound (A3) and polymerizable liquid crystal compound (A4) having the structures shown below were prepared. Polymerizable liquid crystal compound (A3) was prepared in the same manner as described in JP-A-2019-003177. Polymerizable liquid crystal compound (A4) was prepared in the same manner as described in JP-A-2009-173893.

重合性液晶化合物（Ａ４）：

Polymerizable liquid crystal compound (A3):

Polymerizable liquid crystal compound (A4):

A solution was obtained by dissolving 1 mg of polymerizable liquid crystal compound (A3) in 10 mL of chloroform. The obtained solution was placed in a measurement cell with an optical path length of 1 cm, and the measurement sample was placed in an ultraviolet-visible spectrophotometer (Shimadzu Corporation, "UV-2450") to measure the absorption spectrum. The wavelength at which the maximum absorbance was obtained was read from the obtained absorption spectrum, and the maximum absorption wavelength λmax in the wavelength range of 300 to 400 nm was 356 nm.

The polymerizable liquid crystal compound (A3) and the polymerizable liquid crystal compound (A4) were mixed in a mass ratio of 90:10 to obtain a mixture. 0.1 parts of a leveling agent "BYK-361N" (manufactured by BM Chemie) and 3 parts of a photopolymerization initiator "Irgacure OXE-03" (manufactured by BASF Japan Ltd.) were added to 100 parts of the obtained mixture. Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration was 13%. This was stirred at a temperature of 80°C for 1 hour to prepare a second liquid crystal retardation layer forming composition (2).

(Preparation of second liquid crystal retardation layer (2) with substrate)
The photo-alignment film-forming composition (2) was applied to a biaxially oriented polyethylene terephthalate (PET) film (Diafoil, manufactured by Mitsubishi Plastics, Inc.) as the second substrate layer (2) using a bar coater. The resulting coating layer was dried at 120°C for 2 minutes and then cooled to room temperature to form a dry coating. Thereafter, a UV irradiation device (SPOT CURE SP-9; manufactured by Ushio Inc.) was used to irradiate 100 mJ of polarized ultraviolet light (based on 313 nm) to obtain a photo-alignment film as the second alignment layer (2). The thickness of the second alignment layer (2) measured using an ellipsometer M-220 manufactured by JASCO Corporation was 100 nm.

The second liquid crystal retardation layer forming composition (2) was applied onto the second alignment layer (2) using a bar coater, dried by heating at 120°C for 2 minutes, and then cooled to room temperature to obtain a dried film. Next, a high-pressure mercury lamp ("Uniquer VB-15201BY-A" manufactured by Ushio Inc.) was used to irradiate the dried film with ultraviolet light at an exposure dose of 500 mJ/cm ² (based on 365 nm) under a nitrogen atmosphere, thereby forming a second polymer layer (2) (horizontally aligned liquid crystal cured film) in which the polymerizable liquid crystal compound was cured in a state in which it was aligned horizontally relative to the plane of the second substrate layer (2), and a substrate-attached second liquid crystal retardation layer (2) was obtained as an optical film. The substrate-attached second liquid crystal retardation layer (2) has a layer structure of the second substrate layer (2)/second liquid crystal retardation layer (2) (second alignment layer (2)/second polymer layer (2)). The thickness of the second polymer layer (2) was measured using a laser microscope LEXT OLS4100 manufactured by Olympus Corporation and was found to be 2.0 μm.

The second liquid crystal retardation layer (2) side of the substrate-attached second liquid crystal retardation layer (2) was subjected to a corona treatment, and the substrate-attached second liquid crystal retardation layer (2) was attached to glass via a 25 μm pressure-sensitive adhesive manufactured by Lintec Corporation, and the second substrate layer (2) was peeled off and removed. The in-plane retardation value was measured using a KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. The in-plane retardation values for light with wavelengths of 450 nm, 550 nm, and 650 nm were calculated from Cauchy's dispersion formula obtained from the measurement results of the in-plane retardation values for light with wavelengths of 448.2 nm, 498.6 nm, 548.4 nm, 587.3 nm, 628.7 nm, and 748.6 nm.

As a result, the in-plane retardation values of the second liquid crystal retardation layer (2) were Re(450)=122 nm, Re(550)=140 nm, and Re(650)=144 nm. The relationship between the in-plane retardation values at each wavelength was as follows, and the second liquid crystal retardation layer (2) had reverse wavelength dispersion.
Re(450)/Re(550)=0.87
Re(650)/Re(550)=1.03
[In the formula, Re(450) represents an in-plane retardation value for light having a wavelength of 450 nm, Re(550) represents an in-plane retardation value for light having a wavelength of 550 nm, and Re(650) represents an in-plane retardation value for light having a wavelength of 650 nm.]

[Measurement of light transmittance of second liquid crystal retardation layer]
The second liquid crystal retardation layer side of the second liquid crystal retardation layer with the substrate obtained above was attached to glass via an adhesive layer, and then the second substrate layer was peeled off to obtain a measurement sample (1). The light transmittance at a wavelength of 317 nm of the laminate of the glass and adhesive layer used in the preparation of the measurement sample (1) was measured using an ultraviolet-visible spectrophotometer (Shimadzu Corporation's "UV-2450"), and this was used as a baseline. The light transmittance at a wavelength of 317 nm of the measurement sample (1) was measured in the same manner as above, and the obtained measured value was taken as the light transmittance of the second liquid crystal retardation layer. The results are shown in Tables 1 to 3.

<Preparation of Photocurable Adhesive Composition>
The following components were blended and mixed, and then degassed to prepare a photocurable adhesive composition.
Neopentyl glycol diglycidyl ether (cationic polymerizable compound) (trade name: EX-211L, manufactured by Nagase ChemteX Corporation): 30 parts; 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (cationic polymerizable compound) (trade name: OXT-221, manufactured by Toagosei Co., Ltd.): 13 parts; Bisphenol A type epoxy resin (cationic polymerizable compound) (trade name: EP-4100E, manufactured by ADEKA Co., Ltd., viscosity 13 Pa·s (temperature 25°C)): 45 parts; Aromatic-containing oxetane compound (cationic polymerizable compound) (trade name: TCM-104, manufactured by TRONLY): 12 parts; Photopolymerization initiator (photocationic polymerization initiator) (trade name: CPI-100P, manufactured by San-Apro Co., Ltd., 50% propylene carbonate solution): 2.25 parts (solid content)
・1,4-diethoxynaphthalene (photosensitizer): 1 part

[Measurement of maximum absorption wavelength of photopolymerization initiator]
The maximum absorption wavelength of the photopolymerization initiator used in the adhesive composition was measured by dissolving it in methanol and using an ultraviolet-visible spectrophotometer (Shimadzu Corporation's "UV-2450") The photopolymerization initiator had a maximum absorption wavelength at a wavelength of 305 nm.

<Preparation of adhesive sheet>
(Preparation of Pressure-Sensitive Adhesive Composition)
A reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer, and a stirrer was charged with a mixed solution of 100 parts of ethyl acetate, 99.0 parts of butyl acrylate, 0.5 parts of 2-hydroxyethyl acrylate, and 0.5 parts of acrylic acid, and the internal temperature was raised to 55 ° C. while replacing the air in the apparatus with nitrogen gas to make it oxygen-free. Then, the entire amount of a solution in which 0.12 parts of azobisisobutyronitrile (polymerization initiator) was dissolved in 10 parts of ethyl acetate was added. After the addition of the polymerization initiator, the temperature was maintained for 1 hour, and then ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts/hr while maintaining the internal temperature at 54 to 56 ° C., and the addition of ethyl acetate was stopped when the concentration of the (meth)acrylic resin became 35% by mass, and the temperature was maintained until 6 hours had elapsed from the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% by mass, and an acrylic resin solution (1) was prepared. The resulting acrylic resin had a weight average molecular weight Mw of 1.7 million and a molecular weight distribution Mw/Mn of 3.9. Mw and Mn were measured in terms of standard polystyrene using two "TSKgel GMHHR-H(S)" columns manufactured by Tosoh Corporation connected in series as columns in a GPC apparatus, tetrahydrofuran as an eluent, a sample concentration of 2 mg/mL, a sample introduction amount of 100 μL, a temperature of 40° C., and a flow rate of 1 mL/min.

To 80 parts of the solid content of the acrylic resin solution (1), 20 parts (solid content) of bifunctional acrylate (obtained from Shin-Nakamura Chemical Co., Ltd.; product number "A-DOG"), 2.5 parts of a crosslinking agent (manufactured by Mitsui Chemicals: product name "D-101E" (ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75% by mass)) based on active ingredients, 1.5 parts of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: product name "Irgacure 500"), and 0.3 parts of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: product name "KBM-403") were added, and ethyl acetate was further added to make the solid content concentration 13%, to obtain a pressure-sensitive adhesive composition.

A-DOG is a diacrylate of an acetal compound of hydroxypivalaldehyde and trimethylolpropane, and has the following structure:

(Preparation of Adhesive Layer)
The adhesive composition prepared above was applied to the release-treated surface of a separator made of a release-treated polyethylene terephthalate film [manufactured by Mitsubishi Chemical: MRV (V04) (thickness: 38 μm)] using an applicator so that the thickness after drying was 5 μm, and dried at 100 ° C for 1 minute to prepare an adhesive layer. Next, the surface of the obtained adhesive layer opposite the separator was bonded to the release-treated surface of a separator made of a release-treated polyethylene terephthalate film [manufactured by Mitsubishi Chemical: MRF (thickness: 38 μm)]. Subsequently, ultraviolet light was irradiated under the following conditions to prepare an adhesive sheet.
<UV irradiation conditions>
- Fusion UV lamp system (manufactured by Fusion UV Systems) H bulb used - Accumulated light intensity 250 mJ/ ^cm2

Example 1
(Preparation of Retardation Body (1))
The first liquid crystal retardation layer (1) side of the substrate-attached first liquid crystal retardation layer (1) and the second liquid crystal retardation layer (1) side of the substrate-attached second liquid crystal retardation layer (1) were each subjected to a corona treatment. The adhesive composition prepared above was applied to one of the corona-treated surfaces, and the first liquid crystal retardation layer (1) of the substrate-attached first liquid crystal retardation layer (1) and the second liquid crystal retardation layer (1) of the substrate-attached second liquid crystal retardation layer (1) were bonded together. The adhesive composition was cured by irradiating ultraviolet light from the substrate-attached first liquid crystal retardation layer (1) side to form an adhesive layer (1) as a first adhesive layer. The ultraviolet light was irradiated so that the UVA having a wavelength of 320 nm to 390 nm was 400 mJ/ ^cm2 . A retardation body (1) was obtained as an optical laminate having a layer structure of the second base layer (1)/second liquid crystal retardation layer (1) (second alignment layer (1)/second polymer layer (1))/adhesive layer (1)/first liquid crystal retardation layer (1)/first base layer (1). The thickness of the adhesive layer (1) was 2.0 μm.

(Preparation of optical laminate (1))
The TAC film side of the polarizing plate a was subjected to corona treatment, and the surface of the pressure-sensitive adhesive sheet obtained above from which one separator had been peeled off was attached, and then the other separator was peeled off to expose the pressure-sensitive adhesive layer. The second liquid crystal retardation layer (1) (second polymer layer (1)) exposed by peeling off the second base layer (1) of the retarder (1) was subjected to corona treatment, and was attached to the pressure-sensitive adhesive layer (second adhesive layer) exposed above to obtain an optical laminate (1). The second alignment layer (1) was also peeled off together with the second base layer (1). The layer structure of the optical laminate (1) was polarizing plate a/adhesive layer/second liquid crystal retardation layer (1) (second polymer layer (1))/adhesive layer (1)/first liquid crystal retardation layer (1)/first base layer (1).

(Preparation of Laminate (1) with Optical Film)
The first base layer (1) was peeled off from the optical laminate (1) to obtain a laminate (1) with an optical film. The layer structure of the laminate (1) with the optical film was polarizing plate a/adhesive layer/second liquid crystal retardation layer (1) (second polymer layer (1))/adhesive layer (1)/first liquid crystal retardation layer (1).

[Examples 2 to 4]
The optical laminates (2) to (4) and the laminates (2) to (4) with the optical film were obtained in the same manner as in Example 1, except that the amount of ultraviolet light irradiated from the substrate-attached first liquid crystal retardation layer (1) side to cure the adhesive composition was changed to the amount of light shown in Table 1 to form the adhesive layers (2) to (4).

Example 5
An optical laminate (5) and a laminate with an optical film (5) were obtained in the same manner as in Example 3, except that the thickness of the adhesive layer was changed to the thickness shown in Table 1 to form the adhesive layer (5).

Example 6
(Preparation of Retardation Body (6))
A retarder (6) was obtained in the same manner as in Example 1, except that an adhesive layer (6) having a thickness of 3.5 μm was formed using the adhesive composition prepared above instead of the adhesive layer (1). The retarder (6) has a layer structure of the second base layer (1)/second liquid crystal retardation layer (1) (second alignment layer (1)/second polymer layer (1))/adhesive layer (6)/first liquid crystal retardation layer (1)/first base layer (1).

(Preparation of optical laminate (6) and laminate with optical film (6))
An optical laminate (6) and a laminate with an optical film (6) were obtained in the same manner as in Example 1, except that the retardation body (1) was replaced with the retardation body (6).

Example 7
(Preparation of Retardation Body (7))
The first liquid crystal retardation layer (2) side of the substrate-attached first liquid crystal retardation layer (2) and the second liquid crystal retardation layer (2) side of the substrate-attached second liquid crystal retardation layer (2) were each subjected to a corona treatment. The adhesive composition prepared above was applied to one of the corona-treated surfaces, and the first liquid crystal retardation layer (2) of the substrate-attached first liquid crystal retardation layer (2) and the second liquid crystal retardation layer (2) of the substrate-attached second liquid crystal retardation layer (2) were bonded together. The adhesive composition was cured by irradiating ultraviolet light from the substrate-attached first liquid crystal retardation layer (2) side to form an adhesive layer (7) as a first adhesive layer. The ultraviolet light was irradiated so that the UVA having a wavelength of 320 nm to 390 nm was 400 mJ/ ^cm2 . A retardation body (7) was obtained as an optical laminate having a layer structure of the second base layer (2)/second liquid crystal retardation layer (2) (second alignment layer (2)/second polymer layer (2))/adhesive layer (7)/first liquid crystal retardation layer (2)/first base layer (2). The thickness of the adhesive layer (7) was 2.0 μm.

(Preparation of optical laminate (7))
The TAC film side of the polarizing plate a was subjected to corona treatment, and the surface of the pressure-sensitive adhesive sheet obtained above from which one separator had been peeled off was attached, and then the other separator was peeled off to expose the pressure-sensitive adhesive layer. The second liquid crystal retardation layer (2) (second polymer layer (2)) exposed by peeling off the second base layer (2) of the retarder (3) was subjected to corona treatment, and was attached to the pressure-sensitive adhesive layer (second adhesive layer) exposed above to obtain an optical laminate (7). The second alignment layer (2) was also peeled off together with the second base layer (2). The layer structure of the optical laminate (7) was polarizing plate a/adhesive layer/second liquid crystal retardation layer (2) (second polymer layer (2))/adhesive layer (7)/first liquid crystal retardation layer (2)/first base layer (1).

(Preparation of Laminate (7) with Optical Film)
The first base layer (1) was peeled off from the optical laminate (7) to obtain a laminate (7) with an optical film. The layer structure of the laminate (7) with the optical film was a polarizing plate/adhesive layer/second liquid crystal retardation layer (2) (second polymer layer (2))/adhesive layer (7)/first liquid crystal retardation layer (2).

Example 8
(Preparation of Retardation Body (8))
A retardation film (8) was obtained by the procedure of Example 7, except that the adhesive layer (8) having a thickness of 3.5 μm was formed using the adhesive composition prepared above instead of the adhesive layer (7). The retardation film (8) has a layer structure of the second base layer (2)/second liquid crystal retardation layer (2) (second alignment layer (2)/second polymer layer (2))/adhesive layer (8)/first liquid crystal retardation layer (2)/first base layer (1).

(Preparation of optical laminate (8) and laminate with optical film (8))
An optical laminate (8) and a laminate with an optical film (8) were obtained in the same manner as in Example 7, except that the retardation body (3) was replaced with the retardation body (8).

Example 9
(Preparation of Retardation Body (9))
The first liquid crystal retardation layer (3) side of the substrate-attached first liquid crystal retardation layer (3) and the second liquid crystal retardation layer (2) side of the substrate-attached second liquid crystal retardation layer (2) were each subjected to a corona treatment. The adhesive composition prepared above was applied to one of the corona-treated surfaces, and the first liquid crystal retardation layer (3) of the substrate-attached first liquid crystal retardation layer (3) and the second liquid crystal retardation layer (2) of the substrate-attached second liquid crystal retardation layer (2) were bonded together. The adhesive composition was cured by irradiating ultraviolet light from the substrate-attached first liquid crystal retardation layer (3) side to form an adhesive layer (9) as a first adhesive layer. The ultraviolet light was irradiated so that the UVA having a wavelength of 320 nm to 390 nm was 400 mJ/ ^cm2 . A retardation body (9) was obtained as an optical laminate having a layer structure of the second base layer (2)/second liquid crystal retardation layer (2) (second alignment layer (2)/second polymer layer (2))/adhesive layer (9)/first liquid crystal retardation layer (3) (first polymer layer (3)/first alignment layer (1))/first base layer (2). The thickness of the adhesive layer (9) was 2.0 μm.

(Preparation of optical laminate (9))
The TAC film side of the polarizing plate a was subjected to a corona treatment, and the surface of the pressure-sensitive adhesive sheet obtained above from which one of the separators had been peeled was attached, and then the other separator was peeled off to expose the pressure-sensitive adhesive layer. The second liquid crystal retardation layer (2) (second polymer layer (2)) exposed by peeling off the second base layer (2) of the retarder (9) was subjected to a corona treatment, and was attached to the pressure-sensitive adhesive layer (second adhesive layer) exposed above to obtain an optical laminate (5). The second alignment layer (2) was also peeled off together with the second base layer (2). The layer structure of the optical laminate (9) was polarizing plate a/adhesive layer/second liquid crystal retardation layer (2) (second polymer layer (2))/adhesive layer (9)/first liquid crystal retardation layer (3) (first polymer layer (3)/first alignment layer (1))/first base layer (2).

(Preparation of Laminate (9) with Optical Film)
The first base layer (3) was peeled off from the optical laminate (5) to obtain a laminate (9) with an optical film. The first alignment layer (1) was also peeled off together with the peeling off of the first base layer (2). The layer structure of the laminate (9) with the optical film was a polarizing plate/adhesive layer/second liquid crystal retardation layer (2) (second polymer layer (2))/adhesive layer (9)/first liquid crystal retardation layer (3) (first polymer layer (3)).

Example 10
(Preparation of Retardation Body (10))
A retardation body (10) was obtained by the procedure of Example 9, except that an adhesive layer (10) having a thickness of 3.5 μm was formed using the adhesive composition prepared above instead of the adhesive layer (9). The retardation body (10) has a layer structure of the second base layer (2)/second liquid crystal retardation layer (2) (second alignment layer (2)/second polymer layer (2))/adhesive layer (10)/first liquid crystal retardation layer (3) (first polymer layer (3)/first alignment layer (1))/first base layer (2).

(Preparation of optical laminate (10) and laminate with optical film (10))
An optical laminate (6) and a laminate (10) with an optical film were obtained in the same manner as in Example 9, except that the retardation body (9) was replaced with the retardation body (10).

Comparative Example 1
(Preparation of Retardation Body (c1))
The first liquid crystal retardation layer (c1) side of the substrate-attached first liquid crystal retardation layer (c1) and the second liquid crystal retardation layer (1) side of the substrate-attached second liquid crystal retardation layer (1) were each subjected to a corona treatment. The adhesive composition prepared above was applied to one of the corona-treated surfaces, and the second liquid crystal retardation layer (1) of the substrate-attached second liquid crystal retardation layer (1) and the first liquid crystal retardation layer (c1) of the substrate-attached first liquid crystal retardation layer (c1) were bonded together. The adhesive composition was cured by irradiating ultraviolet light from the substrate-attached first liquid crystal retardation layer (c1) side to form an adhesive layer (c1). The ultraviolet light was irradiated so that the UVA having a wavelength of 320 nm to 390 nm was 400 mJ/cm ² . A retardation body (c1) having a layer structure of the second base layer (1)/second liquid crystal retardation layer (1) (second alignment layer (1)/second polymer layer (1))/adhesive layer (c1)/first liquid crystal retardation layer (c1) (first polymer layer (c1)/first alignment layer (c1))/first base layer (c1) was obtained. The thickness of the adhesive layer (c1) was 2.0 μm.

(Preparation of optical laminate (c1))
One TAC film side of the polarizing plate b was subjected to corona treatment, and the surface of the pressure-sensitive adhesive sheet obtained above from which one separator had been peeled was attached, and then the other separator was peeled off to expose the pressure-sensitive adhesive layer. The second liquid crystal retardation layer (1) (second polymer layer (1)) exposed by peeling off the second base layer (1) of the retarder (c1) was subjected to corona treatment, and was attached to the pressure-sensitive adhesive layer (second adhesive layer) exposed above to obtain an optical laminate (c1). The second alignment layer (1) was also peeled off together with the second base layer (1). The layer structure of the optical laminate (c1) was polarizing plate b/adhesive layer/second liquid crystal retardation layer (1) (second polymer layer (1))/adhesive layer (1)/first liquid crystal retardation layer (c1) (first polymer layer (c1)/first alignment layer (c1))/first base layer (c1).

(Preparation of Laminate (c1) with Optical Film)
The first base layer (c1) was peeled off from the optical laminate (c1) to obtain a laminate (1) with an optical film. The first alignment layer (c1) was also peeled off together with the peeling off of the first base layer (c1). The layer structure of the laminate (1) with the optical film was polarizing plate b/adhesive layer/second liquid crystal retardation layer (1) (second polymer layer (1))/adhesive layer (1)/first liquid crystal retardation layer (1) (first polymer layer (1)).

Example 11
In producing the optical laminate, the corona-treated surface of the polarizing plate a and the corona-treated surface of the second liquid crystal retardation layer (1) (second polymer layer (1)) exposed by peeling off the second base layer (1) of the retardation body (1) were bonded together using the adhesive composition prepared above, and ultraviolet light was irradiated from the retardation body (1) side from which the second base layer was peeled off to harden the adhesive, thereby forming an adhesive layer as a second adhesive layer. Except for this, an optical laminate (11) and a laminate with an optical film (11) were obtained in the same procedure as in Example 1. The ultraviolet light was irradiated so that the UVA having a wavelength of 320 nm to 390 nm was 400 mJ/cm ^2. The thickness of the adhesive layer as the second adhesive layer was 2.5 μm.

Example 12
In producing the optical laminate, the optical laminate (12) and the laminate with the optical film (12) were obtained in the same procedure as in Example 11, except that the ultraviolet light irradiated from the side of the retardation body (1) from which the second base layer was peeled off was irradiated so that the UVA having a wavelength of 320 nm to 390 nm was ⁶⁰⁰ mJ/cm2.

[Examples 13 to 15]
In producing the optical laminate, the optical laminates (13) to (15) and the laminates with optical films (13) to (15) were obtained in the same manner as in Example 11, except that the retarders (6) to (8) were used.

[Measurement of adhesive layer thickness]
The thickness of the adhesive layer was measured using a laser microscope manufactured by Keyence Corporation. The results are shown in Tables 1 to 3.

[Measurement of Light Transmittance Ty of Optical Film]
In the optical laminate and the laminate with the optical film, the polarizing plate/adhesive layer (second adhesive layer)/second liquid crystal retardation layer constitutes an optical film. The light transmittance Ty of this optical film at a wavelength of 317 nm was measured using a UV-visible spectrophotometer (Shimadzu Corporation's "UV-2450") and compared with the light transmittance Tx of the first liquid crystal retardation layer with the substrate at a wavelength of 317 nm. The results are shown in Tables 1 to 3.

[Measurement of remaining amount of photopolymerization initiator in adhesive layer]
The ratio of the photopolymerization initiator contained in the adhesive layer was calculated using the retardation body by the following procedure. First, the first base material layer and the second base material layer were peeled off from the retardation body, and the laminate of the layer structure of the second liquid crystal retardation layer/adhesive layer/first liquid crystal retardation layer was freeze-pulverized, dissolved in a solvent (acetonitrile), and filtered to obtain a test solution. The obtained test solution was subjected to high performance liquid chromatography, and the photopolymerization initiator was quantified from the peak area of the component derived from the photopolymerization initiator. The measurement conditions are as follows.
Equipment: LC-20A series (Shimadzu Corporation)
Column: Kinetex 2.6 μm C18 (4.6 mmφ×100 mm, manufactured by Phenomenex)
Mobile phase: Solution A: Water containing 0.05% trifluoroacetic acid Solution B: Acetonitrile containing 0.05% trifluoroacetic acid Elution conditions: Gradient method Solution B concentration: 10%-30 min-100% (hold for 10 min)
Mobile phase flow rate: 1.0 mL/min Column temperature: 40° C.
Detector: UV detector (wavelength: 254 nm)
Sample injection volume: 5 μL

The proportion of the component derived from the photopolymerization initiator was calculated according to the following formula.
Initiator content in adhesive [%]
= (content per unit volume of component derived from photopolymerization initiator of adhesive layer in test solution [mg/mL]) ÷ (amount of powder when test solution was prepared [mg]) × (amount of solvent used when test solution was prepared [mL]) ÷ (thickness of adhesive layer [μm]) × (total thickness of laminate after first base layer and second base layer are peeled off [μm]) × 100

[Scratch resistance test]
A scratch resistance test was performed on the first liquid crystal retardation layer side surface of the laminate with the optical film (corresponding to the optical laminate shown in FIG. 2 from which the first base layer was peeled off) by reciprocating steel wool #0000 ¹⁰ times at a load of 250 g/cm2. Thereafter, according to JIS K 7136, the haze of the laminate with the optical film was measured, and the change in haze before and after the scratch resistance test (ΔHz [%] = (haze after scratch resistance test) - (haze before scratch resistance test)) was calculated and evaluated according to the following criteria. The results are shown in Tables 1 to 3.
A: ΔHz was less than 2%.
B: ΔHz was 2% or more and less than 4%.
C: ΔHz was 4% or more.

[Evaluation of heat wrinkles]
The laminate with the optical film was cut to a size of full width (TD direction) x 0.5 m (MD direction) and placed on an inspection table. The MD direction is the absorption axis direction of the polarizer, and the TD direction is a direction perpendicular to the MD direction. A fluorescent lamp with three wavelengths was placed parallel to the TD direction above the inspection table, and the galvanized iron-like unevenness in the MD direction was observed from a distance of 50 cm from the optical film laminate, and evaluated according to the following criteria. The results are shown in Tables 1 to 3.
A: No irregularities are visible.
B: Slight irregularities are visible.
C: Irregularities are visible.

[Evaluation of Adhesion]
The first base layer was peeled off from the optical laminate, and the exposed surface was attached to glass via a pressure-sensitive adhesive layer. Next, 100 (10 x 10) 1 mm square crosshatch marks were cut from the polarizing plate side so as to penetrate the optical laminate (from which the first base layer was peeled off) on the glass, and used as a measurement sample (2). Under conditions of a temperature of 23°C and a relative humidity of 55%, a 24 mm wide adhesive tape (cellophane adhesive tape CT405AP-24, manufactured by Nichiban) was attached so as to cover the entire 100 crosshatch marks formed on the measurement sample (2), and then the adhesive tape was peeled off in a direction of 45° to the crosshatched surface. The number of crosshatch marks remaining on the glass of the measurement sample (2) was counted and evaluated according to the following criteria. The results are shown in Tables 1 to 3.
A: The number of remaining cross hatches was 80 or more and 100 or less.
B: The number of remaining cross hatches was 50 or more and less than 80.
C: The number of remaining cross hatches was 0 or more and less than 50.

1 to 3 Optical laminate, 11 First liquid crystal retardation layer, 13 First liquid crystal retardation layer with substrate, 16 First substrate layer, 20 Optical film, 21 Second liquid crystal retardation layer (optical film), 23 Second liquid crystal retardation layer with substrate (optical film), 26 Second substrate layer, 31 First adhesive layer (adhesive layer), 32 Second adhesive layer, 50 Polarizing plate (optical film).

Claims (14)

An optical laminate comprising a pressure-sensitive adhesive layer and a first liquid crystal retardation layer with a substrate,
the pressure-sensitive adhesive layer is a cured product layer of a photocurable pressure-sensitive adhesive composition,
The first liquid crystal retardation layer with substrate includes, in order from the pressure-sensitive adhesive layer side, a first liquid crystal retardation layer and a first substrate layer,
The first liquid crystal retardation layer has a first polymer layer containing a polymer of a polymerizable liquid crystal compound,
the first base layer is peelable from the first liquid crystal retardation layer,
The optical laminate, wherein the first liquid crystal retardation layer with the substrate has a light transmittance Tx of 20% or more at a wavelength of 317 nm. The optical laminate according to claim 1, wherein the light transmittance Ts of the first base layer at a wavelength of 317 nm is 20% or more. the first substrate layer is a film substrate,
The optical laminate according to claim 1 , wherein the resin constituting the film substrate is triacetyl cellulose. The optical laminate according to claim 1 or 2, wherein the thickness of the first base layer is 40 μm or less. The optical laminate according to claim 1 or 2, wherein the first liquid crystal retardation layer has positive wavelength dispersion. The optical laminate according to claim 1 or 2, wherein the first liquid crystal retardation layer is the first polymer layer. The pressure-sensitive adhesive composition contains a photopolymerization initiator,
The optical laminate according to claim 1 , wherein a residual amount of the photopolymerization initiator in the pressure-sensitive adhesive layer is 0.050% by mass or less. The optical laminate according to claim 1 or 2, wherein the thickness of the adhesive layer is 2 μm or more. The pressure-sensitive adhesive composition contains a photopolymerization initiator,
The optical laminate according to claim 1 or 2, wherein the photopolymerization initiator has a maximum absorption wavelength in the wavelength range of 280 nm or more and 340 nm or less. The optical laminate according to claim 1 or 2, further comprising an optical film on the side of the adhesive layer opposite to the first liquid crystal retardation layer. The optical film includes at least one of a polarizing plate including a polarizing element and a second liquid crystal retardation layer,
The optical laminate according to claim 10 , wherein the second liquid crystal retardation layer has a second polymer layer containing a polymer of a polymerizable liquid crystal compound. The optical laminate according to claim 10, wherein the light transmittance Ty of the optical film is equal to or smaller than the light transmittance Tx of the first liquid crystal retardation layer with the substrate. A method for producing the optical laminate according to claim 1 or 2,
A step (S1) of forming a coating layer of the pressure-sensitive adhesive composition on the first liquid crystal retardation layer side of the first liquid crystal retardation layer with a substrate;
and (S2) forming the pressure-sensitive adhesive layer by irradiating the coating layer formed in the step (S1) with light through the substrate-attached first liquid crystal retardation layer. the light is ultraviolet light,
The method for producing an optical laminate according to claim 13, wherein an integrated light amount of the light irradiated to the coating layer in the step (S2) is 10 mJ/cm ² or more and 1000 mJ/cm ² or less.

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