TW201712376A - Polarizing plate for curved image display panel - Google Patents

Abstract

An objection of the present invention is to provide a polarizing plate for curved image display panel, which is capable of suppressing peeling and lifting on a display panel in a curved state even after long-term use and/or being used under high temperature environment. The polarizing plate used in a curved image display panel has an average curvature radius R, a thickness H, and has a horizontal direction length L1 in a planar state, wherein the thickness H1 of the polarizing plate on the concave side satisfies the following formula (1) when the polarizing plate laminated on the curved image display panel: L1(H+H1)/2R ≤ 0.4 (1).

Description

Polarized plate for curved image display panel

The present invention relates to a polarizing plate used in a curved image display panel, and a curved image display panel including the polarizing plate.

Conventionally, as a polarizing plate used in various image display panels such as a liquid crystal display panel and an organic electroluminescence (organic EL) display panel, a polarizing plate having a structure in which a polyvinyl alcohol-based resin film is used has been known. A polarizing plate having a structure in which a protective film such as a triacetyl cellulose film is laminated on one or both sides of a polarizing film that adsorbs a dichroic dye such as iodine or a dichroic dye (for example, Patent Document 1 to 3). Such a polarizing plate can be further laminated with various optical layers such as a retardation film or an optical compensation film, and bonded to an image display element such as a liquid crystal cell or an organic EL display device to constitute an image display panel.

(previous technical literature) (Patent Literature)

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-211196

[Patent Document 2] Japanese Patent Laid-Open No. Hei 10-062624

[Patent Document 3] Japanese Patent Laid-Open No. Hei 07-134212

In recent years, studies on image display devices of various shapes have been conducted from the viewpoint of design. Among them, based on the difference in distance from the viewer to the center of the screen and the side to the side, the reason for the immersive feeling can be obtained, and the interest in the curved image display device such as the curved liquid crystal television is increasing, and Develop various products.

Even in the curved image display device, it is necessary to use a polarizing plate as in the case of the planar image display device. However, in order to manufacture the curved image display device, the conventional polarizing plate disclosed in the above Patent Documents 1 to 3 is used for the curved image. When the panel is displayed, as time passes, the polarizing plate is peeled off or floated from the curved image display panel. In the curved display panel, peeling or floating of the polarizing plate is particularly likely to occur on the concave side (viewing side), resulting in poor display in the viewing area. Moreover, the occurrence of peeling or floating of the polarizing plate from the curved display panel is particularly remarkable in a high temperature environment. Therefore, if the heat of the light source is exposed for a long period of time due to long-term use or the like, or when it is easy to form a high-temperature and humid environment, and different use areas, more severe peeling or floating may occur.

Therefore, the object of the present invention is to solve the above-mentioned problems that may occur in a polarizing plate used for a curved image display panel, and to provide a polarizing plate for a curved image display panel, even after a long period of use and/or in a high temperature environment. The use of the lower one can also suppress the peeling or floating of the display panel from the curved state.

The present invention provides the following preferred aspects [1] to [8].

[1] A polarizing plate which is a polarizing plate having a curved surface image display panel having an average radius of curvature R (mm) and a thickness H (mm) and having a horizontal length of L1 (mm) in a planar state, wherein the polarizing plate is used. When the plate is bonded to the curved image display panel, the thickness H1 (mm) of the polarizing plate on the concave side satisfies the following formula (1): L1 (H + H1) / 2R ≦ 0.4 (1).

[2] The polarizing plate according to the above [1], wherein the curved surface image display panel has a thickness H of 0.4 mm or more.

[3] The polarizing plate according to the above [1] or [2] wherein the dimensional change rate after drying at 80 ° C for 250 hours is 3% or less.

[4] The polarizing plate according to any one of [1] to [3] wherein the polarizing film in the polarizing plate is a stretched/dyed polyvinyl alcohol film.

[5] The polarizing plate according to any one of [1] to [4] wherein the curved image display panel has an average radius of curvature R of 900 to 7000 mm.

[6] The polarizing plate according to any one of the above [1], wherein the horizontal length L1 of the polarizing plate is 500 mm or more in a planar state.

[7] A curved surface image display panel comprising a concave side polarizing plate and a convex side polarizing plate, wherein the concave side polarizing plate is any one of the above [1] to [6] Polarizer.

[8] A curved image display panel comprising a concave side polarizing plate and a convex side polarizing plate, wherein the concave side polarizing plate and the convex side polarizing plate are the above [1] to [6] A polarizing plate as described.

According to the present invention, it is possible to provide a polarizing plate for a curved image display panel, which can suppress peeling or floating of the display panel from a curved state even after long-term use and/or use in a high-temperature environment.

1‧‧‧ concave side polarizer

2‧‧‧ convex side polarizer

3‧‧‧Image display components

10‧‧‧Adhesive layer

11‧‧‧Protective layer

12‧‧‧ polarizing film

13‧‧‧Surface treatment layer

Fig. 1 is a schematic view showing a curved image display panel having an average radius of curvature.

Fig. 2 is a cross-sectional view showing an image display panel including a curved state of a polarizing plate.

Fig. 3 is a cross-sectional view showing a configuration of a polarizing plate and a configuration of a curved image display panel.

Fig. 4 shows an example of the absorption axis direction of the polarizing plate in the curved image display device.

Fig. 5 shows an example of the absorption axis direction of the polarizing plate in the curved image display device.

Hereinafter, embodiments of the present invention will be described in detail.

In addition, the "planar state" in the present invention means a state in which the curved portion is not included and the whole is flat. Further, the "surface state" as a whole refers to a state in which one arc is formed to bend the whole and a curved portion formed by one or a plurality of arcs to form a curved surface as a whole. The "average radius of curvature" in the present invention is an average value of the radii of curvature at three points of the left and right end portions and the central portion of the image display panel. That is, in the FIG. 1, the average value of radius of curvature-based (R + R _{of the left and right} + R) / 3 The calculated.

The present invention relates to a polarizing plate used in a curved image display panel having an average radius of curvature R (mm) and a thickness H (mm). When the polarizing plate of the present invention has a horizontal length L1 (mm) in a planar state and is bonded to the curved image display panel, the thickness H1 (mm) of the polarizing plate on the concave side satisfies the following formula (1). : L1 (H + H1) / 2R ≦ 0.4 (1) Further, in the present invention, the concave side indicates the viewing side of the curved image display panel, and the convex side means the side opposite to the concave side.

Here, on the image display panel having the horizontal length L1 and the thickness H in the planar state, a polarizing plate having the same horizontal length and having a thickness H1 is bonded and curved to have an average radius of curvature R (where R When it is defined as the radius to the center of the thickness of the panel (refer to Fig. 2), the length of the center portion of the panel is based on the reference. On the other hand, the horizontal length of the polarized plate after the surface modification (defined as the length of the center position of the thickness of the polarizing plate) is calculated as the arc length of the radius of curvature {R-(H+H1)/2}. The inventors of the present invention have found that the change from L1 to the length is the focus of solving the problem of the present invention. Therefore, in the present invention, the following equation for lowering the amount of change: L1-L1{R-(H+H1)/2}/R=L1(H+H1)/2R, that is, 0.4 or less, It is extremely important to suppress the peeling or floating of the polarizing plate.

The value of L1(H+H1)/2R in the formula (1) is 0.40 or less, preferably 0.38 or less, more preferably 0.35 or less, and still more preferably 0.30 or less. When the value of L1(H+H1)/2R in the formula (1) is less than or equal to the above upper limit value, it is more difficult to cause an image of the polarizing plate from the curved state even after a long period of use or use in a high temperature environment. The peeling or floating of the display panel. Further, the value of L1(H+H1)/2R in the formula (1) is generally 0.01 or more.

The curved image display panel is generally not bent in the vertical direction (vertical direction), but is curved in a horizontal direction (left-right direction) so that the viewer side becomes a concave surface and the opposite side (a backlight unit or the like) becomes a convex surface. The shape is such that the central axis is a shape of a portion of the cylinder in the vertical direction (up and down direction).

The curved image display panel preferably has a thickness of 0.4 mm or more, more preferably 0.8 mm or more, and more preferably 1.0 mm or more. When the thickness H of the curved image display panel is equal to or higher than the above-described lower limit value, various materials can be used as the member used in the curved image display panel, and it is industrially advantageous even if the display panel is easily operated when the display panel is enlarged. Further, the thickness H of the curved image display panel is generally 2.0 mm or less.

The curved image display panel has an average radius of curvature R of preferably 7000 mm or less, more preferably 6600 mm or less, more preferably 5,000 mm or less, and most preferably 4,000 mm or less, and particularly preferably 3,000 mm or less. The curved image display panel has an average radius of curvature R of, for example, 300 mm or more, preferably 900 mm or more, more preferably 1000 mm or more, and still more preferably 1200 mm or more. The curved image display panel has an average radius of curvature R of preferably 900 mm to 7000, more preferably 1000 to 6600 mm. When the average curvature radius R of the curved image display panel is below the above upper limit value, the difference between the distance from the viewer to the center of the screen and the edge of the screen can be made. Become smaller and get an immersive experience. When the average curvature radius R of the curved image display panel is equal to or higher than the above lower limit value, the polarizing plate may be further peeled off or floated from the image display panel in a curved state due to long-term use or use in a high-temperature environment. inhibition.

The average radius of curvature R of the curved image display panel also varies depending on the machine used. In the case of a machine having a small display such as a personal computer or a mobile vehicle, the average radius of curvature R is often small (the bending rate is large). Moreover, a machine having a large display such as a curved display television also reduces the average radius of curvature R to improve the sense of presence. The use of the polarizing plate of the present invention in a long period of time and/or a high temperature environment in a state where the average radius of curvature R is small is excellent in the effect of suppressing peeling or floating of the polarizing plate from the display panel, and thus can be used, for example, to 900 to 7000 mm, especially a curved image display panel having an average radius of curvature R of 900 to 5000 mm or even 1000 to 4000 mm.

The horizontal direction L1 of the polarizing plate of the present invention in the planar state is preferably 500 mm or more, more preferably 700 mm or more, still more preferably 1100 mm or more, and most preferably 1400 mm or more. When the horizontal direction length L1 of the polarizing plate of the present invention is equal to or higher than the lower limit value in the planar state, the horizontal length of the curved image display panel that can be used is increased, and the sense of presence in the screen can be further obtained. Further, the horizontal direction L1 of the polarizing plate of the present invention in the planar state is generally 2,500 mm or less. Further, the horizontal direction of the polarizing plate coincides with the horizontal direction of the curved image display device including the curved image display panel, and the vertical direction of the polarizing plate is orthogonal to the horizontal direction. The polarizing plate of the present invention is in a planar state The length in the vertical direction is determined by the horizontal length L1 and the aspect ratio of the curved image display panel.

When a conventional polarizing plate is used in the manufacture of a curved image display panel, even if it is used for a long period of time in a normal temperature environment, the risk of peeling or floating of the polarizing plate from the image display panel in a curved state is high, and the length is long. The opening of time or the use in a high temperature environment further promotes the occurrence of peeling or floating of the polarizing plate from the image display panel in a curved state. Although the reason is not limited to a specific theory, it is considered to be caused by deformation or compressive stress in the horizontal direction due to the curved surface of the polarizing plate. In order to suppress the deformation/compression stress, the method of changing the thickness H1 of the polarizing plate in response to the average curvature radius R, the thickness H, and the horizontal length L1 of the curved image display panel is considered to have an image display for suppressing the state of the polarizing plate from the curved surface. The effect of peeling or floating of the panel. In the present invention, by determining the thickness H1 of the polarizing plate by satisfying the above formula (1), it is possible to suppress peeling or floating of the polarizing plate.

The polarizing plate of the present invention preferably has a dimensional change ratio of 3.0% or less after 250 hours of drying at 80 ° C, more preferably 2.0% or less, and even more preferably 1.5% or less. When the dimensional change rate of the polarizing plate is equal to or less than the above upper limit value, it is possible to suppress the use of a long period of time or the contraction and/or expansion of the polarizing plate in a high temperature environment, and therefore, the image display panel in which the polarizing plate is less likely to be in a curved state is more likely to occur. Peeling or floating. Further, the above dimensional change ratio of the polarizing plate is generally 0% or more.

The dimensional change rate can be controlled by suppressing the dimensional change of the polarizing film which increases the shrinkage and expansion of the polarizing plate. The dimensional change of the polarizing film can be, for example, a manufacturing condition such as changing the stretching ratio of the polarizing film or The type is controlled by increasing the rigidity of the protective layer adjacent to the polarizing film or the like. Specifically, it is preferable to control the stretching ratio to be 8 times or less, more preferably 7.5 times or less, or more preferably 7 times or less, to control the dimensional change.

Further, the dimensional change rate can be calculated by cutting the polarizing plate to a size of 100 mm × 100 mm and not bonding it to the glass, and measuring the initial size and the size after drying at 80 ° C for 250 hours. Of course, the dimensional change rate when the glass is bonded to the glass via the adhesive is naturally smaller than the dimensional change rate when the unbonded glass is used. Further, although depending on the type of the adhesive, the dimensional change rate when the glass is not bonded is generally about 1/2 to 1/15.

The polarizing plate of the present invention is not particularly limited as long as it is generally provided with a polarizing plate. For example, in a preferred embodiment, the polarizing plate includes a polarizing film and is laminated on the adhesive layer. A protective film on one or both sides of the polarizing film, and an adhesive layer for bonding to the image display element, and optionally an optical layer.

In one embodiment of the invention, the polarizing plate is composed of a protective layer, a polarizing film, a protective layer and an adhesive layer, and optionally an optical layer. Among them, the polarizing film and the protective layer are laminated via an adhesive.

When the configuration of one embodiment of the polarizing plate and the curved image display panel of the present invention is described with reference to Fig. 3, the polarizing plate of the present invention is sequentially laminated from the layer adjacent to the image display element (3). The adhesive layer (10), the protective layer (11), the polarizing film (12), the protective layer (11), and an optional optical layer (not shown) are formed. Further, in general, the polarizing film (12) and the protective layer (11) are laminated via an adhesive. Moreover, the curved image display panel of the present invention is in the present invention In one embodiment, the image display element (3) and the concave side polarizing plate (1) and the convex side polarizing plate which are respectively bonded to the image display element (3) via the adhesive layer (10) (2) constituted. In one embodiment of the present invention, the concave-side polarizing plate (1) is sequentially formed of an adhesive layer (10), a protective layer (11), and a polarizing film from a layer adjacent to the image display element (3). 12), a protective layer (11) and an optional surface treatment layer (13) and/or an optical layer, the convex side polarizing plate (2) is from a layer adjacent to the image display element (3), The order is composed of an adhesive layer (10), a protective layer (11), a polarizing film (12), a protective layer (11), and an optical layer as needed.

Hereinafter, each constituent component of the polarizing plate of the present invention will be described in detail.

<adhesive layer>

In order to form an adhesive for the adhesive layer, a conventionally known adhesive can be used without particular limitation. For example, an acrylic, rubber, urethane, polyoxyl, or polyvinyl ether-based substrate can be used. Adhesive for polymers. Further, it may be an energy ray hardening type adhesive or a thermosetting type adhesive. Among these, an acrylic resin excellent in transparency, adhesion, reworkability, weather resistance, heat resistance, and the like is preferably used as an adhesive for the base polymer.

The acrylic adhesive is not particularly limited, and is preferably butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate or 2-ethylhexyl (meth)acrylate. A (meth) acrylate-based base polymer; or a copolymerized base polymer containing two or more of these (meth) acrylates or the like is suitable. Further, a polar single system is copolymerized in the base polymer. Examples of the polar monomer include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylamide, 2-N,N-dimethylaminoethyl (meth)acrylate, A monomer having a carboxyl group, a hydroxyl group, a decylamino group, an amine group, or an epoxy group, such as glycidyl (meth)acrylate.

These acrylic adhesives can be used singly, but generally in combination with a crosslinking agent. The cross-linking agent is exemplified by a compound which is a divalent or polyvalent metal ion and forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound which forms a guanamine bond with a carboxyl group; is a polyepoxide or The polyol compound forms an ester bond with a carboxyl group; it is a polyisocyanate compound and forms a guanamine bond with a carboxyl group. Among them, polyisocyanate compounds are widely used.

The energy ray-curable adhesive has a property of being hardened by irradiation with energy rays such as ultraviolet rays or electron beams, and has adhesiveness even before irradiation of energy rays, and can be adhered to an adherend such as a film, and energy is passed through An adhesive that is hardened by irradiation of radiation to adjust the properties of the adhesion. In the case of an energy ray hardening type adhesive, it is particularly preferable to use an ultraviolet curing type adhesive. The energy ray-curable adhesive is generally composed of an acrylic adhesive and an energy ray polymerizable compound as a main component. The crosslinking agent is usually further formulated, and a photopolymerization initiator or a photosensitizer or the like may be formulated as needed.

The adhesive, in addition to the above-mentioned base polymer and cross-linking agent, may also contain, for example, an adhesive, a cohesive force, a viscosity, an elastic modulus, a glass transition temperature, etc., such as a natural substance or a composition. Resins, tackifying resins, antioxidants, antistatic agents, UV absorbers Additives such as a collector, a dye, a pigment, an antifoaming agent, an etchant, a photopolymerization initiator, and a thermal polymerization initiator. Further, fine particles may be contained to form an adhesive layer which exhibits light scattering properties. Examples of the ultraviolet absorber include a salicylate-based compound, a diphenylketone-based compound, a benzotriazole-based compound, a cyanoacrylate-based compound, and a nickel complex compound.

In the adhesive which constitutes the adhesive layer in the present invention, it is preferable to contain a decane-based compound, and in particular, it is preferred that the acrylic resin before the crosslinking agent is prepared in advance contains a decane-based compound. In order to improve the adhesion of the decane-based compound to the glass, by including a decane-based compound, the adhesion between the image display element and the adhesive layer sandwiched by the glass substrate can be improved, and a high adhesion force can be secured to the display panel. It is also difficult to peel off or float from the display panel in a curved state during use in a period and/or a high temperature environment.

The adhesive layer can be applied, for example, by using an adhesive as described above as an organic solvent solution, on a film or layer (for example, a polarizing film or the like) to be laminated, by a slit coater or a gravure coater. Set it by drying it. Further, it may be provided by a method of transferring a sheet-like adhesive formed on a plastic film (referred to as a separation film) subjected to release treatment to a film or layer to be laminated. The thickness of the adhesive layer is not particularly limited, and is preferably in the range of 2 to 40 μm, more preferably in the range of 5 to 35 μm, and even more preferably in the range of 10 to 30 μm. When the thickness of the adhesive layer is at least the above lower limit value, peeling or floating which occurs during long-term use and/or use in a high-temperature environment can be further suppressed. When the thickness of the adhesive layer is less than or equal to the above upper limit value, the increase in the thickness of the polarizing plate is suppressed, and as a result, the adhesive layer is less likely to be deformed in the curved state, and the use for a long period of time can be suppressed and/or Or peeling or floating during use in a high temperature environment. Thereby, it is possible to suppress a decrease in the display function around the bezel of the image display device.

In a preferred aspect, the adhesive layer of the polarizing plate of the present invention is an acrylic resin of butyl acrylate, methyl acrylate, 2-phenoxyethyl acrylate, 2-hydroxyethyl acrylate and a copolymer of acrylic acid; A decane compound and an isocyanate compound as a crosslinking agent.

In a preferred aspect, the polarizing plate of the present invention comprises an adhesive layer. The adhesion of the adhesive layer to the glass measured at 23 ° C and 50% RH (hereinafter also referred to as "the adhesion to glass (planar, 23 ° C)" is preferably 1.0 N / 25 mm or more. More preferably 2.0N/25mm or more. When the adhesion of the adhesive layer to the glass (planar, 23° C.) is 1.0 N/25 mm or more, it can be more effectively suppressed during long-term continuous use, long-term use, and/or high-temperature use, movement, storage, and the like. The polarizing plate peels off or floats from the curved image display panel. In the present invention, the glass adhesion (planar, 23 ° C) is preferably 3.0 N / 25 mm or more, and particularly preferably 4.0 N / 25 mm or more.

Further, in the polarizing plate of the present invention, the adhesion of the adhesive layer to the glass measured in the curved state (hereinafter, "the adhesion to the glass (curved surface, 23 ° C)") is 1.5 N/25 mm or more. Good, better than 2.5N/25mm. The glass adhesive force (curved surface, 23 ° C) of the polarizing plate of the present invention is preferably 3.5 N/25 mm or more, and more preferably 4.5 N/25 mm or more. The adhesion to the glass measured in the state of the curved surface is not necessarily the same as the adhesion to the glass measured in the planar state, and is not changed according to a certain rule such as a simple proportional relationship. Since the polarizing plate of the present invention is used in a curved image display device, it is adhered to the glass only by the planar state. In order to control the adhesion of the polarizing plate to the glass, the control of the adhesion of the glass in a curved state to a certain range is related to the control of the adhesion of the polarizing plate to the image display element in the actual use state. In particular, when the adhesion to the glass (curved surface, 23 ° C) is 1.5 N / 25 mm or more, or even 2.5 N / 25 mm or more, even after the polarizing plate is assembled to the curved image display panel, during long-term use, or It is also possible to ensure sufficient adhesion to the image display panel due to exposure to light source heat for a long period of time or in a transportation environment where it is easy to form a high-temperature and high-humidity environment, and it is difficult to generate a polarizing plate from a curved state. The image shows the peeling or floating of the panel.

The adhesion of the polarizing plate to the glass (planar, 23 ° C) and the adhesion to the glass (curved surface, 23 ° C) from the viewpoint of sufficiently ensuring the adhesion to the image display panel in a long period of time and/or a high temperature environment ) are preferably 2.0N/25mm or more, preferably 3.0N/25mm or more, and 4.0N/25mm or more.

On the other hand, in the manufacturing process of the curved image display panel, when the image display element is bonded to the polarizing plate or when the bonding loss occurs after bonding, the manufacturing procedure of the conventional flat image display panel may be the same as In the case of a flat state, it is reworked (that is, the rear panel is reused), but it is also presumed that the surface is reworked. When rework is performed in the curved state, in addition to the compressive stress experienced in the state of being curved, compressive stress is further applied in order to peel the polarizing plate from the image display panel. Therefore, compared with the rework in the planar state, the peeling of the polarizing plate from the curved image display panel during the rework of the curved state state is technically more difficult, especially when the adhesion of the polarizing plate is higher, in order to Stripping polarizer The compressive stress is increased. Therefore, for example, at the time of peeling, the risk of cracking of the glass sheet constituting the display panel or the like is likely to occur.

When the adhesion to the glass is too high, peeling or floating of the polarizing plate from the image display panel does not occur, but the reworkability may be caused as described above, and therefore, the polarizing plate of the present invention is measured in a planar state. The glass adhesion (planar, 23 ° C) is preferably 20.0 N / 25 mm or less, more preferably 15.0 N / 25 mm or less, more preferably 10.0 N / 25 mm or less, and particularly preferably 6.0 N / 25 mm or less. Further, the glass adhesion (curved surface, 23 ° C) is preferably 20.0 N / 25 mm or less, more preferably 15.0 N / 25 mm or less, more preferably 10.0 N / 25 mm or less, and particularly preferably 6.0 N / 25 mm or less. .

When the upper limit of the glass adhesion force is within the above range, in the manufacturing process of the curved image display panel, when the polarizing plate generates or finds a bonding loss, the polarizing plate is easily reworked from the display panel. From the viewpoint of reworkability, in the present invention, it is preferable that the glass adhesion (planar, 23 ° C) and the glass adhesion (curved surface, 23 ° C) are 20.0 N / 25 mm or less.

When the polarizing plate of the present invention comprises an adhesive layer, the adhesion to the glass (planar, 23 ° C) is 20.0 N / 25 mm or less, further 15.0 N / 25 mm or less, especially 10.0 N / 25 mm or less, particularly 6.0 N / 25 mm. Hereinafter, even if it is 4.0 N/25 mm or less, since the formula (1) is satisfied, peeling or floating can be suppressed.

The glass adhesion (planar, 23 ° C) is a polarizing plate cut to a predetermined size, adhered to a flat glass substrate through the adhesive layer, autoclaved, and allowed to stand at 23 ° C, 50% RH for 24 hours. After that, the polarizing plate is peeled off from the glass substrate at a predetermined speed in the 180° direction. value. The glass adhesion (curved surface, 23 ° C) is the same as that for the glass adhesion (planar, 23 ° C), the polarizing plate has been attached to the test piece of the glass plate, so that the test piece is processed along The state of the metal plate having a radius of curvature of 2,500 mm was fixed, and after standing at 23 ° C and 50% RH for 24 hours, the value measured by the polarizing plate was peeled off.

More detailed measurement methods for glass adhesion (planar, 23 ° C) and adhesion to glass (curved surface, 23 ° C) are as described in the examples below.

In the polarizing plate of the present invention, the adhesion of the adhesive layer to the glass measured in a planar state after drying at 80 ° C for 250 hours (hereinafter also referred to as "the adhesion to glass (plane, 80 ° C)") It is preferably 7.0N/25mm or more, more preferably 9.0N/25mm or more, and even more preferably 11.0N/25mm or more. Further, in the polarizing plate of the present invention, the adhesion of the adhesive layer measured in the curved state after drying at 80 ° C for 250 hours (hereinafter also referred to as "adhesion to glass (curved surface, 80 ° C)" The description is preferably 8.0 N/25 mm or more, more preferably 10.0 N/25 mm or more, and even more preferably 12.0 N/25 mm or more. Moreover, since the test piece is broken at the time of measurement due to an increase in the adhesive force, the above-mentioned respective adhesion to the glass measured after drying at 80 ° C for 250 hours cannot be regarded as a numerical value, which is a special feature of the present invention. One of the good looks.

When the adhesion to each glass measured after drying at 80 ° C for 250 hours is as described above, sufficient adhesion can be ensured to the display panel even when used for a long period of time and/or a high temperature environment. It is difficult to cause peeling or floating of the display panel from the curved state. a polarizing plate having a certain range of adhesion to glass (planar, 23 ° C), dried at 80 ° C at 250 It is particularly advantageous for the polarizing plate of the present invention to have a glass adhesion as measured as described above after an hour.

The glass adhesion (plane, 80 ° C) is better than the glass adhesion (flat, 23 ° C) 5.0N / 25mm or more, better than 7.0N / 25mm or more, higher than 10.0 N/25mm or more is especially good. Moreover, it is preferable that the glass adhesion (curved surface, 80 ° C) is 5.0 N/25 mm or more higher than the glass adhesion (curved surface, 23 ° C), and is preferably higher than 7.0 N/25 mm or more. Out of 10.0N/25mm or more is especially good. In the polarizing plate having a certain range of adhesion to glass (planar, 23 ° C), the adhesion to each glass measured after drying at 80 ° C for 250 hours is measured at 23 ° C, 50% RH. When the adhesion to each of the glass is 5.0 N/25 mm or more, it is bonded to the image display element in the initial state of bonding after bonding to the image display element, and it is necessary to use it from a normal temperature to a low temperature environment. The adhesion can be easily carried out at the same time. Moreover, even when exposed to heat of a light source for a long period of time or when it is easy to be transported in a high-temperature and humid environment, and in a long period of time and/or a high-temperature environment, it is possible to ensure sufficient adhesion to the display panel, which is difficult to generate. The peeling or floating of the display panel of the curved state.

The difference between the adhesion to the glass (plane, 80 ° C) and the adhesion to the glass (planar, 23 ° C), and the adhesion to the glass (curved surface, 80 ° C) and the adhesion to the glass (curved surface, 23 ° C), The upper limit is not particularly limited, but is generally 20.0 N/25 mm or less.

The adhesion to the glass (curved surface, 80 ° C) is preferably higher than the adhesion to the glass (planar, 23 ° C) by 5.0 N / 25 mm or more. It is better for 7.0N/25mm or more, and it is especially good for those above 10.0N/25mm. When the difference between the adhesion to the glass (curved surface, 80 ° C) and the adhesion to the glass (planar, 23 ° C) is within the above range, the bonding and the reworkability in the planar state are easy, even after the surface is curved and / In the use in a high-temperature environment, etc., it is also possible to ensure sufficient adhesion to the display panel, and it is difficult to cause peeling or floating of the display panel from the curved state.

The above adhesion to glass (plane, 80 ° C) and adhesion to glass (curved surface, 80 ° C), in addition to the test piece at 80 ° C, dry environment for 250 hours, can still be used with the above adhesion to the glass (planar 23 ° C) was measured in the same manner as the glass adhesion (curved surface, 23 ° C).

The adhesion of the adhesive layer to the glass varies depending on the type of the component constituting the adhesive layer, the content ratio thereof, the formation conditions (drying, active energy ray irradiation conditions), and the thickness after formation, so that it is adhered to the glass as desired. The composition, the content ratio, the formation conditions, and the thickness of the adhesive layer may be appropriately selected according to the force. Specifically, for example, by using an acrylic resin as a constituent component of an adhesive constituting the adhesive layer, a decane-based compound, and a layer thickness of the thickened adhesive layer, the adhesion of the adhesive layer to the glass can be improved. Further, by changing the kind and ratio of the monomer constituting the acrylic resin, the type of the decane-based compound, and the content thereof, the glass adhesion can be controlled to a desired value.

<polarized film>

The polarizing film which can constitute the polarizing plate of the present invention is a film having a function of linearly polarizing light by incident natural light, and can be used, for example, in polyethylene. In the enol-based resin film, a dichroic dye is adsorbed and aligned. In the case of the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film, a polyvinyl acetate-based resin can be used for saponification. In the aspect of the polyvinyl acetate-based resin, in addition to the polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer such as vinyl acetate and other monomers copolymerizable therewith (for example, ethylene-vinyl acetate copolymerization) may be mentioned. Things, etc.). Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylium ammonium amides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is generally from 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin can be modified, and for example, aldehyde-modified polyethylene formaldehyde, polyvinyl acetal, and polyvinyl butyral can be used. The degree of polymerization of the polyvinyl alcohol-based resin is generally from 1,000 to 10,000, preferably from 1,500 to 5,000.

Such a polyvinyl alcohol-based resin can be used as a film of a polarizing film by film formation. The film forming method of the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a conventional method. The film thickness of the embryonic film containing the polyvinyl alcohol-based resin is not particularly limited, but is preferably 10 to 150 μm, preferably 15 to 100 μm, more preferably 20 to 80 μm, in view of easiness of stretching.

The polarizing film is generally produced by a step of uniaxially stretching a polyvinyl alcohol-based resin film such as a polyvinyl alcohol film, and dyeing the polyvinyl alcohol-based resin film with a dichroic dye. a step of adsorbing a dichroic dye; a step of treating the polyvinyl alcohol-based resin film having adsorbed the dichroic dye with an aqueous solution of boric acid; and The step of washing is followed by washing. The stretched/dyed polyvinyl alcohol film thus produced is preferably used as a polarizing film user from the viewpoint of industry. Further, the stretched/dyed polyvinyl alcohol film refers to an extended polyvinyl alcohol film containing a dichroic dye (adsorbed), and the stretching ratio is as follows.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be carried out before the dyeing of the dichroic dye, or simultaneously with the dyeing, or after the dyeing. When the uniaxial stretching is carried out after dyeing, the uniaxial stretching can be carried out before the boric acid treatment or in the boric acid treatment. Uniaxial extension can also be performed during these plural phases. In the case of uniaxial stretching, it may be uniaxially stretched between rolls having different circumferential speeds, or may be extended to a single axis using a heat roll. Further, the uniaxial stretching may be a dry stretching in which the film is stretched in the air, or may be a wet stretching in which the polyvinyl alcohol-based resin film is swollen with a solvent. From the viewpoint of suppressing deformation of the polarizing film, the stretching ratio is preferably 8 times or less, more preferably 7.5 times or less, and still more preferably 7 times or less. Further, from the viewpoint of exhibiting the function as a polarizing film, the stretching ratio is generally 4.5 times or more.

In the method of dyeing a polyvinyl alcohol-based resin film as a dichroic dye, for example, a method in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing a dichroic dye can be used. As the dichroic dye, for example, iodine or a dichroic dye can be used. The dichroic dye includes, for example, a dichroic direct dye containing a disazo compound such as C.I. Direct Red 39, and a dichroic direct dye containing a arsenazo, an anthracene azo compound or the like. Moreover, it is preferable that the polyvinyl alcohol-based resin film is subjected to immersion treatment in water before the dyeing treatment.

When iodine is used as a dichroic dye, it is generally used in A method of dyeing an aqueous solution containing iodine and potassium iodide by impregnating a polyvinyl alcohol-based resin film. The content of iodine in the aqueous solution is usually 0.01 to 1 part by mass per 100 parts by mass of water, and the content of potassium iodide is usually 0.5 to 20 parts by mass per 100 parts by mass of water. When iodine is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is generally 20 to 40 ° C, and the immersion time (dyeing time) in the aqueous solution is generally 20 to 1800 seconds.

When a dichroic dye is used as the dichroic dye, a method in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing a water-soluble dichroic dye and dyed is generally used. The content of the dichroic dye in the aqueous solution is generally from 1 × 10 ^-4 to 10 parts by mass per 100 parts by mass of water, preferably from 1 × 10 ^-3 to 1 part by mass, and from 1 × 10 ^-3 to 1 × 10 ^-2 parts by mass is more preferable. The aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing auxiliary. When a dichroic dye is used as the dichroic dye, the temperature of the dye aqueous solution used in the dyeing is generally 20 to 80 ° C, and the immersion time (dyeing time) in the aqueous solution is generally 10 to 1800 seconds.

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

The polyvinyl alcohol-based resin film treated with boric acid is generally subjected to a water washing treatment. The water washing treatment can be carried out, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of the water in the water washing treatment is generally 5 to 40 ° C, and the immersion time is usually 1 to 120 seconds. After washing with water, drying treatment is carried out to obtain a polarizing film. The drying treatment can be carried out using a hot air dryer or a far infrared heater. The drying treatment temperature is usually from 30 to 100 ° C, preferably from 40 to 95 ° C, more preferably from 50 to 90 ° C. The drying treatment time is generally from 60 to 600 seconds, preferably from 120 to 600 seconds.

The polyvinyl alcohol-based resin film is subjected to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment to obtain a polarizing film. The thickness of the polarizing film can be made, for example, to 5 to 40 μm.

Compared with the conventional polarizing film which is formed by stretching a polyvinyl alcohol resin film, the coating type film polarizing film has a small dimensional change rate, and therefore, by using a coating type film polarizing film, it can be suppressed. The use of a long period of time and/or the change in the size of the polarizing plate used in a high temperature environment. Further, it contributes to the thinning of the polarizing plate and is applied to the present invention. For the coating type film polarizing film, for example, those shown in JP-A-2012-58381, JP-A-2013-37115, International Publication No. 2012/147633, and International Publication No. 2014/091921 can be used.

<protection layer>

In a preferred aspect, the polarizing plate of the present invention has a laminate layer as described above. A protective layer on one or both sides of the polarizing film. The protective layer contributes to prevention of shrinkage and swelling of the polarizing film and prevention of deterioration of the polarizing film due to temperature, humidity, ultraviolet rays, etc., and therefore the polarizing plate of the present invention preferably has a protective layer.

The material for forming the protective layer is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropic properties. For example, a polyester-based polymer such as polyethylene terephthalate or polyethylene naphthalate, a cellulose-based polymer such as diethyl phthalocyanine or triethylene fluorene cellulose, or a polymethyl methacrylate may be mentioned. A styrene polymer such as an acrylic polymer such as an ester, a polystyrene or an acrylonitrile-styrene copolymer (AS resin), or a polycarbonate polymer. Further, examples of the polymer forming the protective layer include, for example, polyethylene, polypropylene, polyolefin having a ring- or norbornene structure, and a polyolefin-based polymer such as an ethylene-propylene copolymer; Polymer; amide-based polymer such as nylon or aromatic polyamine; quinone imine polymer; lanthanide polymer; polyether lanthanide polymer; polyetheretherketone polymer; polyphenylene sulfide polymerization a vinyl alcohol polymer; a vinylidene chloride polymer; a vinyl butyral polymer; an acrylate polymer; a polyoxymethylene polymer; an epoxy polymer; or a blend of the above polymers; Things and so on. The protective layer may be formed of a thermosetting type or an ultraviolet curing type resin such as an acrylic type, an urethane type, an urethane urethane type, an epoxy type or a polyoxymethylene type, as a cured layer. Among them, a hydroxyl group having reactivity with an isocyanate crosslinking agent is preferred, and a cellulose-based polymer is particularly preferred. The thickness of the protective layer is not particularly limited, but is generally 500 μm or less, preferably 1 to 300 μm, more preferably 5 to 200 μm, and even more preferably 30 to 100 μm. Moreover, the protective layer can be supplemented with optical compensation functions. A transparent protective film or the like is formed. Further, it is preferable that the thickness of the outer protective layer on the back side of the polarizing film is the same as the thickness of the inner protective layer on the viewing side of the polarizing film, or that the outer protective layer is thicker than the inner protective layer. In this manner, particularly when the polarizing plate is heated, curling of the outer and inner protective layers or curling in a direction of low rigidity can be suppressed, so that peeling or floating from the display panel is less likely to occur. This system is particularly suitable for applications on the concave side.

By increasing the rigidity of the protective layer adjacent to the polarizing plate, the shrinkage of the polarizing film can be suppressed. Therefore, by controlling the rigidity of the protective layer, the dimensional change of the polarizing plate can be suppressed. The term "rigidity" as used herein is defined as the ratio of the tensile elastic modulus (hereinafter referred to as 23 ° C elastic modulus) of the film used for the protective layer at room temperature (23 ° C) to the film thickness, and at 80. The tensile elastic modulus (hereinafter referred to as 80 ° C elastic modulus) under the condition of ° C is multiplied by the film thickness. In particular, by increasing the rigidity obtained by multiplying the elastic modulus of the 80 ° C by the film thickness, the dimensional change of the polarizing plate in a high temperature environment can be suppressed. For example, a cellulose-based polymer typified by triacetonitrile cellulose preferably has an elastic modulus of from 3,000 to 5,000 MPa at 23 ° C and an elastic modulus of from 2,000 to 4,000 MPa at 80 ° C, and polymethyl methacrylate is used. The acrylic polymer represented by the invention is preferably a modulus of elasticity of from 2000 to 4000 MPa at 23 ° C and a modulus of elasticity of from 800 to 2500 MPa at 80 ° C, such as a polyolefin-based polymer having a norbornene structure at 23 ° C. It is preferred that the modulus is in the range of 2,000 to 3,000 MPa and the modulus of elasticity at 80 ° C is in the range of 1,500 to 3,000 MPa.

The surface layer of the protective layer not attached to the polarizing film may have a surface treatment layer, for example, may have a hard coat layer, an anti-reflection layer, an anti-adhesive layer, and an anti-glare layer. An optical layer such as a layer or a diffusion layer.

The hard coat layer is provided for the purpose of preventing the surface of the polarizing plate from being scratched, etc., and a hardened film which is excellent in hardness and smoothness, etc., which is formed of, for example, an ultraviolet curable resin such as acrylic or polyoxygen, can be applied thereto. The surface of the protective layer is formed in a manner or the like. The antireflection layer is provided for the purpose of preventing external light from being reflected from the surface of the polarizing plate, and can be achieved by formation of a conventional antireflection film or the like. Moreover, the anti-adhesive layer is provided for the purpose of preventing adhesion to adjacent layers.

The anti-glare layer is provided for the purpose of preventing external light from being reflected from the surface of the polarizing plate and obstructing the observation of light transmitted from the polarizing plate, and the like, for example, by roughening by surface blasting or embossing. Alternatively, a fine uneven structure is formed on the surface of the protective layer in such a manner that the transparent fine particles are blended. Examples of the fine particles contained in the surface fine concavo-convex structure include cerium oxide, aluminum oxide, titanium oxide, zirconium oxide, tin oxide, indium oxide, cadmium oxide, and cerium oxide having an average particle diameter of 0.5 to 50 μm. Inorganic fine particles which can be electrically conductive, and transparent fine particles containing organic fine particles such as a crosslinked or uncrosslinked polymer. When the surface fine uneven structure is formed, the content of the fine particles is usually 2 to 50 parts by mass, preferably 5 to 25 parts by mass, per 100 parts by mass of the transparent resin forming the surface fine uneven structure. The anti-glare layer may have a diffusion layer (viewing angle expansion function, etc.) for diffusing the polarizing plate through light to amplify a viewing angle or the like. Further, the protective layer may contain a conventional additive as needed. Examples of the additives include ion trapping agents, antioxidants, sensitizing assistants, light stabilizers, tackifiers, thermoplastic resins, fillers, flow control agents, plasticizers, defoamers, and colors. , antistatic agents and UV absorbers.

Further, the antireflection layer, the anti-adhesion layer, the diffusion layer, the anti-glare layer, and the like may be provided separately from the protective layer itself, and an individual different from the protective layer may be provided as another optical layer.

<Binder layer>

The polarizing film and the protective layer are generally passed through an adhesive. The adhesive used for the polarizing film and the protective layer is not particularly limited. However, from the viewpoint of thinning the formed adhesive layer, for example, the water-based one, that is, the adhesive component is dissolved in water, Or the adhesive component is dispersed in water. For example, an adhesive containing a polyvinyl alcohol-based resin or an urethane resin can be used as an adhesive component. When the protective layer is provided on both sides of the polarizing film, the adhesive used in the subsequent step may be the same or different.

When a polyvinyl alcohol-based resin is used as the adhesive component, the polyvinyl alcohol-based resin may be a partially saponified polyvinyl alcohol or a fully saponified polyvinyl alcohol, or may be a carboxyl-modified polyvinyl alcohol or an ethyl acetonitrile. A modified polyvinyl alcohol-based resin such as polyvinyl alcohol, hydroxymethyl modified polyvinyl alcohol or amine-modified polyvinyl alcohol is modified. Usually, an aqueous solution of a polyvinyl alcohol-based resin can be prepared by using a polyvinyl alcohol-based resin as an adhesive for an adhesive component. The concentration of the polyvinyl alcohol-based resin in the subsequent agent is usually from 1 to 10 parts by mass, preferably from 1 to 5 parts by mass, per 100 parts by mass of the water.

In order to improve the adhesiveness, a polyvinyl alcohol-based resin is used as an adhesive for the adhesive component, and a curable component such as glyoxal or a water-soluble epoxy resin and/or a crosslinking agent is preferably used. Water-soluble epoxy resin, For example, a polyamine amine obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid, and a mixture of epichlorohydrin can be suitably used. Amidamine polyamine epoxy resin. Examples of the commercial product of the polyamine polyamine epoxy resin include "Sumirez resin 650" (manufactured by Sumika Chemtex Co., Ltd.), "Sumirez resin 675" (manufactured by Sumika Chemtex Co., Ltd.), and "WS- 525" (made by Japan PMC). The amount of the curable component and/or the crosslinking agent to be added (the total amount at the time of simultaneous addition) is usually from 1 to 100 parts by mass, preferably from 1 to 50 parts by mass, per 100 parts by mass of the polyvinyl alcohol-based resin. . When the amount of the curable component and/or the crosslinking agent added is within the above range, the adhesion is improved, and an adhesive layer which exhibits good adhesion can be formed.

Further, when the adhesive component contains an urethane resin, it is preferred to use a mixture of a polyester-based ionic polymer type urethane resin and a compound having a glycidyloxy group. Here, the polyester-based ionic polymer type urethane resin refers to an urethane resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced into the skeleton. The ionic polymer type urethane resin is emulsified directly in water to form an emulsion without using an emulsifier, and thus is suitable as a water-based adhesive. A polyester-based ionic polymer type urethane resin is known per se. For example, Japanese Laid-Open Patent Publication No. Hei 7-97504 discloses a polymer dispersant for dispersing a phenol resin in an aqueous medium. An example of a polyester-based ionic polymer type urethane resin and a compound having a glycidoxy group is shown in Japanese Laid-Open Patent Publication No. 2005-70140 and JP-A-2005-208456. The mixture acts as an adhesive, A type of a cycloolefin-based resin film is bonded to a polarizing film containing a polyvinyl alcohol-based resin.

The coating of the polarizing film and/or the protective layer (protective film) bonded thereto may be carried out by a conventional method, and for example, a casting method, a wire-bar coating method, a gravure coating method, or the like may be used. Notch wheel coating method, blade coating method, slit coating method, dip coating method, spray coating method, and the like. The casting method is a method in which a film of an object to be coated is moved in a substantially vertical direction, a substantially horizontal direction, or an oblique direction therebetween, while allowing an adhesive to flow downward to the surface and expanding. After the application of the adhesive, the polarizing film and the protective layer bonded thereto are laminated, and the film is bonded by a pinch roll or the like. The bonding using the film of the roll may be, for example, a method of applying pressure by a roll or the like after the application of the adhesive, and uniformly pressing and expanding; after applying the adhesive, pressurizing between the roll and the roll Press the method of expansion, etc. At this time, the material of the roller to be used may be metal or rubber. Moreover, when the film is expanded by pressing between a plurality of rolls, the plurality of rolls may be of the same material or different materials.

Further, in order to improve the adhesion, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, or saponification treatment may be suitably performed on the surface of the polarizing film and the protective layer. As the saponification treatment, for example, a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide can be mentioned.

After the above bonding, the adhesive is cured by drying to obtain a polarizing plate. The drying treatment is carried out, for example, by blowing hot air, and the temperature is usually in the range of 40 to 100 ° C, preferably in the range of 60 to 100 ° C. Moreover, the drying time is generally from 20 to 1200 seconds.

The thickness of the adhesive layer formed of the adhesive after drying is generally 0.001 to 5 μm, preferably 0.01 to 2 μm, more preferably 0.01 to 1 μm. When the thickness of the coating layer is within the above range, sufficient adhesion can be ensured, and the appearance is also good, and the thickness of the polarizing plate is further improved. Therefore, it is suitable for the polarizing plate of the present invention.

After the above drying, it may be aged at room temperature or higher for at least half a day, preferably for several days or more to obtain sufficient bonding strength. The preferred curing temperature is in the range of from 30 to 50 ° C, more preferably in the range of from 35 to 45 ° C. When the aging temperature is within the above range, it is difficult to cause so-called "winding" in the wound state. Further, the humidity at the time of ripening is not particularly limited, and the relative humidity may be in the range of 0 to 70% RH. The curing time is generally from 1 to 10 days, preferably from 2 to 7 days.

Further, as the above-mentioned adhesive, a photocurable adhesive can also be used. Examples of the photocurable adhesive agent include a mixture of a photocurable epoxy resin and a photocationic polymerization initiator, or a mixture of a photocurable acrylic resin and a photoradical polymerization initiator. When a photocurable adhesive is used, the photocurable adhesive is cured by irradiation with an active energy ray. The light source of the active energy ray is not particularly limited, and is preferably an active energy ray having a light-emitting distribution at a wavelength of 400 nm or less. Specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, a black lamp, and a microwave are preferable. It is preferable to activate a mercury lamp and a metal halide lamp.

The light irradiation intensity of the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive, and is not particularly limited, but the irradiation intensity in the wavelength region effective for activation of the polymerization initiator is 0.1 to 6000 mW. More preferably, /cm ^{2 is more} preferably 10 to 1000 mW/cm ^{2 and} even more preferably 20 to 500 mW/cm ² . When the irradiation intensity is within the above range, the reaction time can be ensured, and the yellowing of the epoxy resin and the deterioration of the polarizing film due to the heat radiated from the light source and the heat generation of the photocurable adhesive at the time of hardening can be suppressed. . The light irradiation time of the photocurable adhesive may be appropriately selected depending on the photocurable adhesive to be cured, and is not particularly limited, but the cumulative light amount expressed as the product of the irradiation intensity and the irradiation time is set. It is preferably from 10 to 10000 mJ/m ² , more preferably from 50 to 1000 mJ/m ² , still more preferably from 80 to 500 mJ/m ² . When the cumulative light amount of the photocurable adhesive is within the above range, a sufficient amount of the active species derived from the polymerization initiator can be generated to make the hardening reaction more sure, and the irradiation time is not excessively long and can be maintained well. Productive.

Further, when the photocurable adhesive is cured by irradiation with an active energy ray, a polarizing plate such as a polarizing film, a transmittance, a hue, and a transparency of various films constituting the protective layer and the optical layer are used. It is better for each function to perform hardening without lowering the condition.

<optical layer>

The polarizing plate of the present invention may further laminate an optical layer such as a retardation film, a viewing angle compensation film, and a brightness enhancement film as needed.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an alignment film of a liquid crystal polymer, and an alignment layer film support of a liquid crystal polymer. The extension processing can be performed by, for example, an inter-roll stretching method, a long gap stretching method, a tenter stretching method, It is carried out by a blown film stretching method or the like. The stretching ratio is generally 1.1 to 3 times in the case of uniaxial stretching. The thickness of the retardation film is not particularly limited, and is usually 10 to 200 μm, preferably 20 to 100 μm.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, and methyl cellulose. Polycarbonate, polyarylate, polyfluorene, polyethylene terephthalate, polyethylene naphthalate, polyether oxime, polyphenylene sulfide, polyphenylene ether, polyallyl fluorene, polyethylene Alcohol, polyamine, polyimine, polyolefin, polyolefin having a norbornene structure, polyvinyl chloride, cellulose-based polymer, or various binary, ternary copolymers, grafts Copolymers and blends, etc. These polymer materials are oriented (stretched films) by stretching or the like.

In the liquid crystal polymer, for example, a main chain type or a side chain type in which a conjugated linear atomic group (mesogenic) which imparts a liquid crystal alignment property is introduced into a main chain or a side chain of a polymer may be mentioned. Things. Specific examples of the main chain type liquid crystal polymer include a structure in which a spacer portion imparting flexibility and a mesogenic group are bonded, for example, a nematic alignment type polyester liquid crystal polymer or a disk-shaped polymerization. And cholesterol-type polymers. Specific examples of the side chain type liquid crystal polymer include, for example, polysiloxane, polyacrylate, polymethacrylate or polymalonate as a main chain skeleton, and are separated by a side chain. An intermediate portion of a para-substituted cyclic compound unit containing a nematic alignment imparting property, and the like, is a spacer composed of a conjugating atomic group. The liquid crystal polymers are rubbed, for example, by a surface of a film of polyimine or polyvinyl alcohol which has been formed on a glass plate. The cerium oxide is subjected to oblique heat evaporation to be equal to the solution of the liquid crystal polymer on the alignment treatment surface for heat treatment.

The retardation film may have a phase difference corresponding to the purpose of use such as coloring or viewing angle compensation such as birefringence of various wavelength plates or liquid crystal layers, or may be controlled by laminating two or more types of retardation films. Optical characteristics such as phase difference.

The viewing angle compensation film is a film for expanding the viewing angle when the image of the liquid crystal display device is viewed from a direction slightly inclined toward the screen. In the viewing angle compensation film, for example, an alignment layer such as a liquid crystal polymer is supported on an alignment film such as a retardation film or a liquid crystal polymer or a transparent substrate. A general retardation film is a polymer film which has been uniaxially stretched in the direction of the surface and has birefringence. On the other hand, the retardation film used as the viewing angle compensation film is biaxially stretched in the past direction and has birefringence. The polymer film and the birefringent polymer or the oblique alignment film-like biaxially stretched film which is uniaxially extended in the direction of the surface and which also extends in the thickness direction and has a refractive index in the thickness direction. The aspect of the oblique alignment film may be, for example, a method in which the heat shrinkable film is subsequently subjected to elongation treatment or/and shrinkage treatment of the polymer film under the action of the shrinkage force generated by heating; or the liquid crystal is polymerized. The object is inclined and the like. The raw material polymer of the material of the retardation film is the same as the polymer described in the previous retardation film, and can be appropriately selected to prevent coloration caused by the change in the viewing angle due to the phase difference caused by the liquid crystal cell. Wait for the purpose of expanding the perspective of good viewing.

Moreover, from the perspective of achieving a good perspective of good viewing, A viewing angle compensation film in which an optically anisotropic layer containing an alignment layer of a liquid crystal polymer, particularly an inclined alignment layer containing a discotic liquid crystal polymer, is supported by a triacetyl cellulose film is suitably used.

A polarizing plate to which a polarizing plate and a brightness enhancing film are bonded is generally used in the inner portion of the liquid crystal cell. The brightness enhancement film system can display a linearly polarized light of a predetermined polarization axis or a circularly polarized light of a predetermined direction when a natural light is incident by a backlight of a liquid crystal display device or the like, or a reflection from the inside, etc., and the other light is transmitted. A polarizing plate obtained by laminating a brightness enhancement film and a polarizing plate is configured to inject light from a light source such as a backlight to obtain a light having a predetermined polarization state, and to prevent light other than the predetermined polarization state from penetrating. Reflect it. Light reflected by the brightness enhancement film surface is further transmitted through a reflection layer provided on the rear side thereof, and then incident on the brightness enhancement film, so that part or all of the light is transmitted as a predetermined polarization state to increase The amount of light that penetrates the brightness enhancing film is supplied, and the polarized light that is hardly absorbed by the polarizing film is supplied to increase the amount of light that can be utilized in liquid crystal image display or the like, thereby improving the brightness. In other words, when light is incident from the inside of the liquid crystal cell through the polarizing film without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizing film is almost absorbed by the polarizing film, and is not worn. Translucent film. In other words, depending on the characteristics of the polarizing film to be used, about 50% of the light is absorbed by the polarizing film, and accordingly, the image can be darkened by reducing the amount of light such as liquid crystal image display. . In the brightness enhancement film, light having a polarization direction that is absorbed by the polarizing film is not incident on the polarizing film, and is repeatedly performed: temporarily reflecting from the brightness enhancement film and then transmitting the reflection layer provided on the rear side thereof. Inverting and re-injecting into the brightness enhancement film, and deflecting and reversing the light between the two After the light direction is polarized by the polarizing direction of the polarizing film, only the polarized light is penetrated and supplied to the polarizing film, so that light such as a backlight can be effectively used for image display of the liquid crystal display device, and the screen can be changed. Bright.

The polarizing plate of the present invention can be produced, for example, by bonding a protective layer to a polarizing film with an adhesive and forming an adhesive layer on the surface of the protective layer on the side where the image display element is bonded. When the polarizing plate of the present invention further includes an optical layer, for example, any of the films constituting the optical layer may be bonded to the protective layer with an adhesive, and an adhesive layer may be formed on the surface opposite to the surface of the protective layer. The polarizing plate of the present invention can be obtained by forming a polarizing plate obtained by laminating the respective films and laminated layers of the polarizing plate so as to have a desired radius of curvature before bonding to the image display element. Further, the surface may be curved after being bonded to the image display element.

When bonding to an image display element, for example, when it is used for a curved liquid crystal display panel, the polarizing plate of the present invention may be bonded to a liquid crystal cell as an image display element via an adhesive layer. Further, when the curved organic EL panel is used, the polarizing plate of the present invention may be attached to the viewing side display surface of the organic EL display element as an image display element by transmitting the polarizing layer.

The curved surface of the polarizing plate is, for example, in the case of a liquid crystal display panel, and can be formed by bending a laminate of the image display element and the concave side and the convex side polarizing plate produced as described above through a predetermined radius of curvature. a method of being fixed to the frame and then placed on the backlight unit; or a backlight unit bent by a predetermined radius of curvature is placed on the laminated body, and the frame is pressed from above.

The polarizing plate of the present invention can be used as a polarizing plate of a curved image display panel such as a curved liquid crystal panel or a curved organic EL panel, and is particularly useful as a polarizing plate of a curved liquid crystal display panel. In the case of a curved image display panel, compressive stress is often generated due to bending of the image display panel. Since the compressive stress is large on the concave side (viewing side), the dimensional change is likely to occur in the polarizing plate on the concave side. On the other hand, the image display element to which the polarizing plate is attached is generally sandwiched by the glass substrate. It is difficult to cause dimensional change, and it is considered that a difference in shrinkage ratio is likely to occur between the concave-side polarizing plate and the image display element. Therefore, on the concave side of the curved image display panel, peeling or floating of the glass sheet is particularly likely to occur. The polarizing plate of the present invention can be used as any of the concave-side polarizing plate and the convex-side polarizing plate constituting the curved image display panel, but has a high suppression effect on peeling or floating in a curved state, and therefore is particularly suitable. As a concave-side polarizing plate assembled to the concave side of the curved image display panel. That is, in an aspect of the present invention, a curved image display panel including a concave side polarizing plate and a convex side polarizing plate is provided, wherein the concave side polarizing plate is the polarizing plate of the present invention. Further, in another embodiment of the present invention, a curved image display panel including a concave side polarizing plate and a convex side polarizing plate is provided, wherein the concave side polarizing plate and the convex side polarizing plate are the polarizing plates of the present invention.

When the polarizing plate of the present invention is used in a liquid crystal display panel, the convex-side polarizing plate and the concave-side polarizing plate are such that the absorption axis directions (extension directions) of the respective polarizing films contained in the polarizing plates are orthogonal to each other. Configuration. For example, as shown in Fig. 4, when the absorption axis direction of the polarizing film contained in the concave-side polarizing plate is horizontal, the polarized light contained in the convex-side polarizing plate The absorption axis direction of the film is perpendicular. Further, as shown in Fig. 5, when the absorption axis direction of the polarizing film contained in the concave-side polarizing plate is perpendicular, the absorption axis direction of the polarizing film contained in the convex-side polarizing plate is horizontal. The absorption axis direction of the polarizing film contained in the concave-side polarizing plate may be a vertical direction or a horizontal direction, or may be an angular direction of 45° with respect to the horizontal direction. In the majority of the articles of the image display panel, the absorption axis direction of the polarizing film contained in the concave-side polarizing plate is horizontal, especially in this case, the shrinkage of the polarizing plate is liable to occur. Such deformation, it is easy to produce peeling or floating of the polarizing plate. According to the polarizing plate of the present invention, even if the absorption axis direction is horizontal, scratching of the surface of the polarizing plate can be suppressed, and the above problem can be solved.

Further, the polarizing plate of the present invention can be applied to a curved image display panel having various screen sizes. For example, it can be used with 5 inches (horizontal length: 100 to 150 mm), 10 inches (horizontal length: 200 to 250 mm), 17 inches (horizontal length: 320 to 400 mm), 32 inches (horizontal direction) Length: 680 to 720 mm), 40 inches (horizontal length: 860 to 910 mm), 46 inches (horizontal length: 980 to 1030 mm), 55 inches (horizontal length: 1180 to 1230 mm), 65 inches ( Curved image display panel with a screen size of horizontal length: 1400 to 1450 mm), 75 inches (horizontal length: 1600 to 1700 mm), and 85 inches (horizontal length: 1800 to 1900 mm). The larger the screen size, the larger the size of each constituent member. In the curved state, in addition to the compressive stress acting on the concave side polarizing plate, the polarizing plate is liable to occur due to the inconsistency in size between the polarizing plate and the image display element. Peeling or floating. Further, in an image display device in which the aspect ratio (length in the vertical direction: length in the horizontal direction) of the screen is 3:4, it is difficult to cause peeling or floating of the polarizing plate, and the aspect ratio of the screen is 9:13 to 9: 23, preferably 9:15 or more, more preferably 9:19 or less, for example, in a 9:16 or 9:21 horizontally wide image display panel, when the surface is curved, except for the compressive stress, the concave side polarizing plate The effect is also that peeling or floating of the polarizing plate is liable to occur due to the inconsistency in size between the polarizing plate and the image display element formation, which is also discovered by the inventors of the present invention. Since the polarizing plate of the present invention has a highly suppressed effect on peeling or floating in a curved state, it is applicable to polarized light for a curved image display panel having various screen sizes, in particular, a large screen size or a horizontal width as described above. board.

The curved image display panel of the present invention including the polarizing plate of the present invention is excellent in suppressing the effect of peeling or floating of the polarizing plate from the image display panel in a long period and/or a high temperature environment.

[Examples]

The invention is further illustrated by the following examples and comparative examples, but the invention is not limited by the examples.

1. Production of polarizing film

A polyvinyl alcohol film (trade name "VF-PE #6000" manufactured by Kuraray Co., Ltd.) having an average polymerization degree of about 2,400 and a saponification degree of 99.9 mol% or more and a thickness of 60 μm was immersed in pure water at 30 ° C, and then 30 °C was immersed in an aqueous solution of iodine/potassium iodide/water in a mass ratio of 0.02/2/100. Then, it was immersed in an aqueous solution of potassium iodide/boric acid/water in a mass ratio of 12/5/100 at 56.5 °C. Subsequently, the film was washed with pure water at 8 ° C, and then dried at 80 ° C to obtain a polarizing film which had been adsorbed to the iodine on the polyvinyl alcohol film. The extension is mainly carried out in iodine dyeing and boric acid treatment, and the total stretching ratio is 6.0 times. The polarizing film thus obtained had a thickness of 22 μm.

2. Production/preparation of protective layer (protective film)

Various protective layers (protective films) were prepared or prepared as described below.

(1) Acrylic resin film (2-A)

70% by mass of the methacrylic resin and 30% by mass of the rubber particles were mixed in a super mixer, and 2% by mass of the benzotriazole-based ultraviolet absorber was added to 100% by mass of the mixture, and melted by a twin-screw extruder. Mix and make into granules. Put the pellet into 65mm In the uniaxial extruder, the film was extruded by a T-die having a temperature of 275 ° C, and the film was cooled by sandwiching the two polishing rolls having a mirror surface to obtain an acrylic resin film (2-A) having a thickness of 80 μm.

Further, as the methacrylic resin, a copolymer of methyl methacrylate/methyl acrylate = 96% / 4% (mass ratio) was used. Further, in the above rubber particles, an elastomer particle having a three-layer structure is used, and the average particle diameter of the particles to the elastomer as the intermediate layer is 240 nm, wherein the three-layer structure of the elastomer particles includes the innermost layer. It is composed of a hard polymer obtained by polymerizing a small amount of allyl methacrylate in methyl methacrylate; the middle layer is mainly composed of butyl acrylate, and styrene and a small amount of methyl group are used. Softening of allyl acrylate The outermost layer is composed of a hard polymer obtained by polymerizing a small amount of ethyl acrylate in methyl methacrylate. Further, in the rubber particles, the total mass of the innermost layer and the intermediate layer accounts for 70% of the entire particles.

(2) Acrylic resin film (2-B) having a hard coat layer

A hard coat treatment was performed on the above acrylic resin film (2-A). Hard coating treatment coating treatment solution (neopentitol triacrylate): 42.5 parts by mass, Irgacure 184: 0.25 parts by mass, polyfluorene (leveling agent): 0.1 parts by mass, cerium oxide (average particle diameter 1 μm) : 12 parts by mass of surface methacrylonitrile-based modified cerium oxide (surface organic component: 4.05 × 10 ^-3 g/m ² ): 7.5 parts by mass, toluene: 34 parts by mass), after drying, by It is carried out by irradiating ultraviolet rays with an ultraviolet illuminator. Thus, an acrylic resin film (2-B) having a hard coat layer having a thickness of 5 μm (total thickness: 85 μm) was obtained.

(3) TAC film (2-C)

A triacetone cellulose film "KC6UAW" (thickness: 60 μm) manufactured by Konica Minolta Opto Co., Ltd. was used as a TAC film (2-C).

(4) TAC film (2-D)

Hard coating treatment was carried out on the above (2-C) TAC film in the same manner as (2-B). Thus, a TAC film (2-D) having a hard coat layer having a thickness of 5 μm (total thickness: 65 μm) was obtained.

(5) COP film (2-E)

A cyclic polyolefin-based biaxially stretched resin film "ZEONOR Film ZB12" (thickness: 52 μm) of Japan Zeon was used as a COP film (2-E).

3. Preparation of adhesive

As the adhesive, a solventless ultraviolet curable adhesive obtained by mixing the following formulation components was used. In addition, % is a content (% by mass) when the total amount of the adhesive is 100% by mass.

‧3,4-Epoxycyclohexenylmethyl-3',4'-epoxycyclohexenecarboxylate ("Celloxide 2021P" manufactured by Daicel Chemical Industry Co., Ltd.): 80%

‧ 1,4-butanediol diglycidyl ether: 19%

‧ Photocationic polymerization initiator based on triarylsulfonium hexafluorophosphate (CPI-100P: 50% propylene carbonate solution containing triarylsulfonium hexafluorophosphate as active ingredient, San-Apro (CPI-100P) manufactured by (share): 1%

4. Modulation of adhesive

In a reaction vessel equipped with a condenser, a nitrogen gas introduction tube, a thermometer, and a stirrer, 81.8 parts by mass of ethyl acetate, 70.8 parts by mass of butyl acrylate, 20.0 parts by mass of methyl acrylate, and 8.0 mass of 2-phenoxyethyl acrylate were fed. The solvent, 1.0 parts by mass of 2-hydroxyethyl acrylate, and 0.6 parts by mass of acrylic acid were heated to 55 ° C while the internal temperature was raised while replacing the air in the apparatus with nitrogen. Then, 0.14 parts by mass of azobisisobutyronitrile as a polymerization initiator was dissolved in 10 parts by mass of ethyl acetate. plus. After the polymerization initiator was added, the temperature was maintained for 1 hour, and then the internal temperature was maintained at 54 to 56 ° C while ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts by mass per hour. When it was 35 mass%, the addition of ethyl acetate was stopped. Further, the temperature was kept at this temperature within 12 hours from the start of the ethyl acetate addition. Finally, ethyl acetate was added so that the concentration of the acrylic resin was adjusted to 20% by mass. This was taken as an acrylic resin.

The weight average molecular weight and the number average molecular weight of the obtained acrylic resin were measured by the following methods. In the GPC installation, a total of five "Shodex GPC KF-802" manufactured by Tosoh's "TSKgel XL" and one Showa Denko (share) and sold by Zhaoguang Trading Co., Ltd. are connected in series. As a column, tetrahydrofuran was used as an eluent, and it was measured by standard polystyrene conversion under the conditions of a sample concentration of 5 mg/mL, a sample introduction amount of 100 μL, a temperature of 40 ° C, and a flow rate of 1 mL/min. The obtained acrylic resin had a weight average molecular weight Mw of 1.42 million and a Mw/Mn of 4.1.

0.5 parts by mass of glycidoxypropyltrimethoxydecane (liquid) as a decane-based compound with respect to 100 parts by mass of the solid content of the acrylic resin (20% by mass of ethyl acetate solution) prepared above (Shin-Etsu KBM-403 manufactured by Chemical Industry Co., Ltd., 0.6 parts by mass of Coronate HXR (polymethylene isocyanate of hexamethylene diisocyanate, a liquid close to 100% by mass of the active ingredient; Japan Polypropylene) Manufactured) and 3.0 parts by mass of N-octyl-4-methylpyridinium hexafluorophosphate were mixed. Next, the solid content concentration is 13% by mass. Ethyl acetate was added to obtain an adhesive.

Example 1

The film (2-D) and the film (2-E) as a protective layer were subjected to corona treatment in advance using a corona treatment machine (manufactured by Kasuga Electric Co., Ltd.), and an adhesive was applied thereon to be bonded to polarized light. membrane. Next, the adhesive is cured by irradiating ultraviolet rays with a metal halide lamp. A layer of 20 μm of the adhesive was formed on the film (2-E) to obtain a concave-side polarizing plate A having a thickness of 0.17 μm (excluding the separation film used in the formation of the adhesive layer).

Further, the same operation as above was carried out, except that the film (2-C) was used instead of the film (2-D), to obtain a convex-side polarizing plate B having a thickness of 0.16 μm (excluding the separation film used in the formation of the adhesive layer).

The polarizing plate A is cut into a width (horizontal length) of 1215 mm × height (longitudinal length) of 683 mm, and is cut in such a manner that the absorption axis direction of the polarizing plate A is wide. Further, the polarizing plate B is cut into a size of 1215 mm in width × 683 mm in height, and is cut in such a manner that the absorption axis direction of the polarizing plate B is high. The cut polarizing plate A is attached to the viewing side (concave side) of a glass panel having a width of 1215 mm, a height of 683 mm, and a thickness of 1.5 mm, and the cut polarizing plate B is attached to the back side of the panel (convex surface). side). Then, the glass panel was bent and fixed so that the average radius of curvature became 4000 mm, and it was kept at 80 ° C for 250 hours under drying. After 250 hours, when the appearance of the panel was observed with the naked eye, peeling or floating of the polarizing plate did not occur. The dimensional change rate measured by the above method was 0.8%. Further, at this time, L1(H+H1)/2R=0.25.

Example 2

The film (2-B) and the film (2-E) as a protective layer were subjected to corona treatment in advance using a corona treatment machine (manufactured by Kasuga Electric Co., Ltd.), and an adhesive was applied thereon to be bonded to polarized light. membrane. Then, the adhesive is hardened by irradiating ultraviolet rays with a metal halide lamp. A layer of 20 μm of the adhesive was formed on the film (2-E) to obtain a concave-side polarizing plate C having a thickness of 0.19 μm (excluding the separation film used in the formation of the adhesive layer).

Further, the same operation as above was carried out except that the film (2-A) was used instead of the film (2-B), and a convex-side polarizing plate D having a thickness of 0.18 mm was obtained.

The polarizing plate C is cut into a size of 1215 mm in width × 683 mm in height, and is cut in such a manner that the absorption axis direction of the polarizing plate C is wide. Further, the polarizing plate D is cut into a size of 1215 mm in width × 683 mm in height, and is cut in such a manner that the absorption axis direction of the polarizing plate D is high. The cut polarizing plate C is attached to the viewing side (concave side) of a glass panel having a width of 1215 mm, a height of 683 mm, and a thickness of 1.5 mm, and the cut polarizing plate D is attached to the back side of the panel (convex surface). side). Then, the panel was bent and fixed so that the average radius of curvature became 4000 mm, and it was kept at 80 ° C for 250 hours under drying. After 250 hours, when the appearance of the panel was observed with the naked eye, peeling or floating of the polarizing plate did not occur. The dimensional change rate measured by the above method was 1.4%. Further, at this time, L1(H+H1)/2R=0.26.

Example 3

In addition to cutting the polarizing plates C and D into a width of 1440 mm × 810 mm in height, and bonding the polarizing plates C and D to a glass panel having a width of 1440 mm × a height of 810 mm and a thickness of 1.5 mm, and an average radius of curvature of 6600 mm. In the same manner as in Example 2 except that the panel was bent and fixed, the peeling or floating of the polarizing plate in the curved panel was evaluated. As a result, no severe peeling or floating of the polarizing plate occurred. The dimensional change rate measured by the above method was 1.4%. Further, at this time, L1(H+H1)/2R=0.18.

Comparative example 1

The peeling or lifting of the polarizing plate in the curved panel was evaluated in the same manner as in Example 2 except that the average radius of curvature of the panel was set to 2,500 mm. As a result, in the short side of the concave-side polarizing plate C, the glass was floated from the side end portion by 50 mm. The dimensional change rate measured by the above method was 1.4%. Further, at this time, L1(H+H1)/2R=0.41.

Example 4

The same operation as in the second embodiment was carried out except that the polarizing plates C and D were cut into a size of 1440 mm wide by 810 mm wide, and the polarizing plates C and D were attached to a glass panel having a width of 1440 mm × a height of 810 mm and a thickness of 1.5 mm. When evaluating the peeling or floating of the polarizing plate in the curved panel, L1(H+H1)/2R=0.30. The occurrence of severe peeling or floating of the polarizing plate is suppressed.

Example 5

In addition to cutting the polarizing plates C and D into a width of 1660 mm × 934 mm When the polarizing plates C and D were attached to a glass panel having a width of 1,660 mm, a height of 934 mm, and a thickness of 1.5 mm, the same procedure as in the second embodiment was performed, and the peeling or floating of the polarizing plate in the curved panel was evaluated. , L1(H+H1)/2R=0.35. The occurrence of severe peeling or floating of the polarizing plate is suppressed.

Example 6

In addition to cutting the polarizing plates C and D into a width of 900 mm × 506 mm, and bonding the polarizing plates C and D to a glass panel having a width of 900 mm × a height of 506 mm and a thickness of 1.5 mm, and an average radius of curvature of 2500 mm. In the same manner as in the second embodiment, when the peeling or lifting of the polarizing plate in the curved panel was evaluated, L1(H+H1)/2R=0.30. The occurrence of severe peeling or floating of the polarizing plate is suppressed.

Example 7

Except that the polarizing plates C and D were cut into a size of 508 mm wide by 286 mm in height, and the polarizing plates C and D were attached to a glass panel having a width of 508 mm × a height of 286 mm and a thickness of 1.5 mm, and the average radius of curvature was set to 2500 mm. In the same manner as in the second embodiment, when the peeling or floating of the polarizing plate in the curved panel was evaluated, L1(H+H1)/2R=0.17. The occurrence of severe peeling or floating of the polarizing plate is suppressed.

Comparative example 2

The peeling or floating of the polarizing plate in the curved panel was performed in the same manner as in Example 4 except that the average radius of curvature of the panel was set to 2500 mm. At the time of evaluation, L1(H+H1)/2R=0.49, causing the occurrence of peeling or floating of the polarizing plate.

Comparative example 3

In the same operation as in Example 5, except that the average radius of curvature of the panel was set to 2500 mm, L1(H+H1)/2R=0.56 was caused when the polarizing plate was peeled off or floated in the curved panel, causing a polarizing plate. The occurrence of flaking or floating.

Comparative example 4

In the same operation as in Example 6 except that the average radius of curvature of the panel was set to 1000 mm, L1(H+H1)/2R=0.76 was caused when the peeling or floating of the polarizing plate in the curved panel was evaluated, causing a polarizing plate. The occurrence of flaking or floating.

Comparative Example 5

When the average radius of curvature of the panel was set to 1000 mm, the same operation as in Example 7 was carried out, and when the peeling or floating of the polarizing plate in the curved panel was evaluated, L1(H+H1)/2R=0.43, causing the polarizing plate The occurrence of flaking or floating.

Example 8

In addition to cutting the polarizing plates A and B into a width of 1050 mm × a height of 600 mm, and bonding the polarizing plates A and B to a width of 1050 mm × a height of 600 mm, thick The glass panel having a degree of 1.5 mm and the panel were bent and fixed so that the average radius of curvature was 2,500 mm, and the peeling or lifting of the polarizing plate in the curved panel was evaluated in the same manner as in the first embodiment. As a result, no severe peeling or floating of the polarizing plate occurred. The dimensional change rate measured by the above method was 0.8%. Moreover, at this time, L1(H+H1)/2R=0.35.

5. Evaluation of glass adhesion (1) Determination of adhesion of glass (a) Determination of adhesion to glass (planar, 23 ° C) and "adhesion to glass (curved surface, 23 ° C)"

Each of the test pieces for measuring the glass adhesion force in the planar state and the curved state produced in Example 1 and Example 2 was subjected to a high pressure of 20 minutes at 50 ° C and 5 kg/cm ² (490.3 kPa, gauge pressure). After the kettle was treated, it was allowed to stand in an environment of 23 ° C and 50% RH for 24 hours, and the glass panel and the polarizing plate were respectively clamped using a universal testing machine (AGS-50NX) manufactured by Shimadzu Corporation, and the temperature was changed to 300 at a speed of 300 mm/min. The polarizing plate is peeled off in the direction of °. The peel strength thus measured was referred to as "adhesion to glass (planar, 23 ° C)" and "adhesion to glass (curved surface, 23 ° C)". The results are shown in Table 1.

(b) Determination of adhesion to glass (plane, 80 ° C) and "adhesion to glass (curved surface, 80 ° C)"

The other groups of the test pieces for measuring the glass adhesion force in the planar state and the curved state produced in Example 1 and Example 2 were subjected to 20 minutes at 50 ° C and 5 kg/cm ² (490.3 kPa, gauge pressure). After autoclaving, it was allowed to stand in an environment of 23 ° C and 50% RH for 24 hours, and then allowed to stand in a dry environment at 80 ° C for 250 hours, and a glass panel was used with a universal testing machine (AGS-50NX) manufactured by Shimadzu Corporation. The polarizing plates were respectively clamped, and the polarizing plate was peeled off at a speed of 300 mm/min to 180°. The peel strength thus measured was referred to as "adhesion to glass (plane, 80 ° C)" and "adhesion to glass (curved surface, 80 ° C)". The results are shown in Table 1.

Claims (9)

A polarizing plate is a polarizing plate having a curved surface image display panel having an average radius of curvature R (mm) and a thickness H (mm) and having a horizontal length of L1 (mm) in a planar state, wherein the polarizing plate is laminated In the curved image display panel, the thickness H1 (mm) of the polarizing plate on the concave side satisfies the following formula (1): L1 (H + H1) / 2R ≦ 0.4 (1). The polarizing plate according to claim 1, wherein the adhesion to the glass measured at a state of 23 ° C and 50% RH is 2.0 N/25 mm or more. The polarizing plate according to claim 1 or 2, wherein the horizontal length L1 of the polarizing plate is 500 mm or more in a planar state. The polarizing plate according to any one of claims 1 to 3, wherein the curved image display panel has a thickness H of 0.4 mm or more. The polarizing plate according to any one of claims 1 to 4, wherein the dimensional change rate after drying at 80 ° C for 250 hours is 3% or less. The polarizing plate according to any one of claims 1 to 5, wherein the polarizing film in the polarizing plate is a stretched/dyed polyvinyl alcohol film. The polarizing plate according to any one of claims 1 to 6, wherein the curved image display panel has an average radius of curvature R of 900 to 7000 mm. A curved image display panel is a curved image display panel comprising a concave side polarizing plate and a convex side polarizing plate, wherein the concave side polarizing plate is The polarizing plate according to any one of claims 1 to 7. A curved image display panel comprising a concave-side polarizing plate and a convex-side polarizing plate, wherein the concave-side polarizing plate and the convex-side polarizing plate are in any one of claims 1 to 7. The polarizing plate.