JP2012068562A - Image display apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent image display apparatus having a protection part, in which the adhesion between a light-curable resin (a curable resin layer) and a functional layer provided on an optical film composing a polarizer can be adequately improved and, furthermore, high contrast and excellent visibility are both achieved.SOLUTION: The image display apparatus has a curable resin layer between a protection part and a polarizer 1 that has an optical film 10 with a functional layer 12 on a film substrate 11 and a polarization film 13 arranged in layers in that order. In the image display apparatus, the functional layer 12 has projecting shapes 16, which are arranged in an irregular form on the film substrate. The arithmetic average roughness Ra of the functional layer 12 is 25 to 300 nm, and the haze of the functional layer 12, resulting from internal scattering, is 0.0 to 1.0%. In addition, the storage elastic modulus of the curable resin layer at 25°C is 1×10Pa or less.

Description

  The present invention relates to an image display device.

  In recent years, for example, a liquid crystal display device as shown in FIG. 1 is known as an image display device having a protection unit.

  The liquid crystal display device 101 has a transparent protective part 103 made of, for example, glass or plastic on a liquid crystal display panel 102. In this case, in order to protect the polarizing plate 1 disposed on the outermost surface of the liquid crystal display panel 102, a gap 90 is provided between the liquid crystal display panel 102 and the protective portion 103 by interposing a spacer 90 between the protective portion 103. Exists. However, the presence of the gap 105 between the liquid crystal display panel 102 and the protection unit 103 causes light scattering, resulting in a decrease in contrast and brightness, and the presence of the gap 105 hinders thinning of the panel. ing.

  In view of such a problem, it is known to fill a space between a polarizing plate disposed on the outermost surface of a liquid crystal display panel and a protective portion with a photocurable resin. Further, for the purpose of improving the contrast of an image display device such as a liquid crystal display panel, a frame-shaped light shielding portion having a predetermined width is provided along the outer peripheral edge of the protection portion. The light-shielding part also has a function of blocking unnecessary light around the liquid crystal display panel, and also has a role of preventing deterioration in display quality due to light leakage.

  However, when the light shielding part is provided on the protective panel, it is sufficient for the photocurable resin (resin cured layer) filled between the polarizing plate disposed on the outermost surface of the image display device such as a liquid crystal display panel and the protective part. There is a problem that light does not reach and hinders curing. If the curing of the resin is insufficient, the quality of the image display device is greatly impaired, and there is a concern that the reliability may be lowered. For example, Patent Documents 1 and 2 disclose improved techniques for poor curing of a photocurable resin (resin cured layer) that is such a void filler.

  The said technique is aiming at improvement by using the photocurable resin whose storage elastic modulus and light transmittance are a specific range.

  On the other hand, the polarizing plate usually has a configuration in which an optical film is bonded to both sides of the polarizing film, but various functional layers may be provided on the optical film. The functional layer includes a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, a λ / 4 plate, an infrared shielding plate, an electromagnetic shielding plate, etc., and is selected according to the purpose. An antireflection layer or the like is common.

  According to the study by the present inventors, although the curing failure of the photocurable resin (resin cured layer) as the void filler is improved by the above technique, it is provided on the optical film constituting the polarizing plate. The adhesion between the functional layer thus obtained and the photocurable resin (resin cured layer) was insufficient, and peeling might occur. In particular, the adhesion failure was remarkable after a weather resistance test assuming use in outdoor applications.

JP 2009-186955 A JP 2005-186959 A

  The present invention has been proposed in view of such circumstances, and an object thereof is to provide a functional layer provided on an optical film constituting a polarizing plate and a photocurable resin in an image display device having a protective portion. An object of the present invention is to provide an excellent image display device which can sufficiently improve the adhesion with the (cured resin layer) and which has both high contrast and excellent visibility.

  The above object of the present invention is achieved by the following configurations.

1. In an image display device having a cured resin layer between a protective part and a polarizing plate in which an optical film having a functional layer on a film substrate and a polarizing film are laminated in this order, the functional layer protrudes The protrusions are irregularly arranged on the film substrate irregularly, the arithmetic average roughness Ra of the functional layer is 25 to 300 nm, and the haze caused by internal scattering is 0. An image display device characterized in that the storage elastic modulus at 25 ° C. of the cured resin layer is 1 × 10 ⁷ Pa or less.

  2. 2. The image display device according to 1 above, wherein the arithmetic average roughness Ra of the functional layer is 65 to 130 nm.

  3. 3. The image display device according to 1 or 2, wherein the functional layer has a surface haze and a haze ratio resulting from surface haze / internal scattering is 3.5 or more.

  4). 4. The image display device according to any one of 1 to 3, wherein the functional layer substantially does not contain fine particles or a non-reactive polymer.

  5. 5. The image display device according to any one of 1 to 4, wherein the image display device is a liquid crystal display device.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness of the functional layer provided in the polarizing plate protective film arrange | positioned on the surface of the image display apparatus which has a protection part, and photocurable resin (resin cured layer) is fully improved. Furthermore, it is possible to provide an excellent image display device in which high contrast and excellent visibility are compatible.

A general liquid crystal display device is also a schematic view. It is a schematic diagram which shows an example of the image display apparatus of this invention. It is a schematic diagram which shows an example of the polarizing plate using the optical film which concerns on this invention. It is explanatory drawing of the protrusion concerning this invention. It is a schematic diagram which shows an example of a structure of a liquid crystal display panel. It is an observation result of the optical interference type surface roughness meter of the optical film 1 surface of an Example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

The image display device of the present invention has a cured resin layer between a protective part and a polarizing plate in which an optical film having a functional layer on a film substrate and a polarizing film are laminated in this order. The functional layer has a protrusion shape, the protrusion shape is irregularly disposed on the film substrate, and the arithmetic average roughness Ra of the functional layer is 25 to 300 nm, and The haze caused by internal scattering is 0 to 1.0%, and the storage elastic modulus at 25 ° C. of the cured resin layer is 1 × 10 ⁷ Pa or less.

  Functionality is obtained by adhering the cured resin layer on a functional layer having irregular shapes and irregularly arranged protrusions on the film substrate and having a specific range of arithmetic average roughness Ra. The adhesion area between the functional layer and the cured resin layer is further increased by using an actinic radiation curable resin having a specific range of storage radiation modulus for the cured resin layer. As a result, it has been found that sufficient adhesion can be obtained after the weather resistance test due to these effects, and the present invention has been achieved.

  In addition, haze caused by internal scattering of the functional layer can be minimized, and surface haze can be suppressed by the close contact between the functional layer and the cured resin layer. Thus, an excellent image display device in which high contrast and excellent visibility are compatible can be provided.

  Hereinafter, the present invention will be described in detail.

<Image display device>
First, an image display apparatus according to the present invention will be described as an embodiment with reference to FIGS. However, the present invention is not limited to this.

  As shown in FIG. 2 (III), which is an example of a completed image display device of the present invention, a drive circuit is connected (not shown), and an optical film having a functional layer according to the present invention on a film substrate is provided. The liquid crystal display panel 102 having the polarizing plate 101 provided on the surface and the protective portion 103 are filled with a cured resin layer 140 so as to be filled.

  The base 20 has a frame 60, and a liquid crystal display panel 102 is attached to an inner region of the frame 60. Further, a backlight 70 is attached to the back side of the liquid crystal display panel 102. The protection part 103 is formed from the translucent member 30 having the same size as the base part 20.

  As the translucent member 30, for example, optical glass or plastic (acrylic resin or the like) can be suitably used.

  For example, a black frame-shaped light shielding portion 50 is provided in the peripheral region of the liquid crystal display panel on one surface side (base 20 side) of the translucent member 30. The light shielding part 50 can be formed by, for example, a printing method.

  A plurality of spacers 90 are intermittently provided at predetermined intervals on the peripheral edge of the frame 60 of the base 20 on the liquid crystal display panel 102 side. The spacer 90 has a thickness of about 0.05 to 1.5 mm, so that the distance between the surfaces of the liquid crystal display panel 102 and the protection unit 103 is maintained at about 1 mm. Further, the bonding of the frame 60 of the base 20 and the protection unit 103 is parallel.

  Next, FIGS. 2 (I) and (II) will be described. FIG. 2I shows a protection by dropping (filling, coating) a predetermined amount of a composition 110 containing an actinic radiation curable resin (hereinafter referred to as a curable resin composition) on the light shielding part 50 side of the protection part 103. FIG. 3 is a diagram in which a unit 103 and a liquid crystal display panel 102 are opposed to each other. Next, in FIG. 2 (II), the protective part 103 is disposed on the spacer 90 of the base part 20, and the curable resin composition 110 and the functional layer of the optical film of the polarizing plate 1 are adhered to each other and protected after adhesion. It is the figure which irradiated the ultraviolet-ray 33 from the part 103 side. Although the irradiation direction of the ultraviolet rays 33 is not particularly limited, it is preferable to irradiate in the direction orthogonal to the surface of the protective part 103 from the viewpoint of uniform curability of the photocurable resin. Further, in addition to the irradiation of the ultraviolet ray 33, for example, an ultraviolet ray irradiation device 32 having a fine irradiation part made of an optical fiber or the like is used, and between the light shielding part 50 and the base part 20, the actinic radiation curable resin composition 110 is applied. UV irradiation may be performed.

  The direction of this ultraviolet irradiation is not particularly limited, but is preferably 0 ° or more and less than 90 ° with respect to the horizontal direction. Moreover, after ultraviolet irradiation, heat treatment is performed as necessary.

  After the ultraviolet irradiation as described above, as shown in FIG. 2 (III), the curable resin composition 110 is cured to form a cured resin layer 140, and the image display device according to the present invention is obtained.

  In FIG. 2, the curable resin composition 110 is dropped (filled and coated) on the protective portion 103 to provide the resin cured layer 140. In the present invention, the functionality of the optical film of the polarizing plate 1 is provided. After the curable resin composition 110 is dropped (filled or coated) on the layer, the base portion 20 including the polarizing plate 1 and the protective portion 103 may be bonded to form the cured resin layer 140.

<Resin cured layer>
Next, the cured resin layer that is one of the components of the present invention will be described. The cured resin layer is a layer provided between a polarizing plate composed of an optical film having functionality and a protective part. One characteristic of the cured resin layer is that the storage elastic modulus (25 ° C.) is 1.0 × 10 ⁷ Pa or less. More preferably, a storage elastic modulus (25 degreeC) is 1 * 10 < ³ > Pa-1 * 10 < ⁷ > Pa.

  The said storage elastic modulus can be measured by the method based on JISK7244. Specifically, it can measure using a viscoelasticity measuring apparatus (Seiko Instruments Co., Ltd. product DMS6100).

  The storage elastic modulus can be adjusted by appropriately adjusting the configuration of the curable resin composition (type of curable resin, additives, blending ratio thereof, etc.), film thickness, and the like. The specific thickness of the cured resin layer is preferably 30 to 200 μm. The refractive index of the cured resin layer is preferably 1.45 or more and 1.55 or less, more preferably 1.51 or more and 1.52 or less, and the transmittance in the visible light region of the cured resin layer is 90% or more. It is preferable that the visibility of the image display image is improved.

  The resin cured layer according to the present invention contains an actinic radiation curable resin, that is, a resin that is cured through a crosslinking reaction by irradiation with actinic rays (also referred to as active energy rays) such as ultraviolet rays and electron beams. The layer is preferably

  The curing shrinkage of the actinic radiation curable resin forming the resin cured layer is preferably 5.0% or less, more preferably 4.5% or less, particularly preferably 4.0% or less, and further preferably 0 to 2. 0%. By adjusting the curing shrinkage rate in such a range, it is possible to prevent distortion at the interface between the cured resin layer 140 and the liquid crystal display panel 102 or the protection unit 103.

  The arithmetic average roughness Ra of the cured resin layer is 6 nm or less, preferably 5 nm or less, more preferably 1 to 3 nm. By adjusting to such arithmetic average roughness Ra, the adhesiveness with the functional layer becomes good.

  It is preferable that the actinic radiation curable resin composition forming the resin cured layer contains a monofunctional actinic radiation curable resin from the viewpoint that the objective effect is satisfactorily exhibited. As the monofunctional actinic radiation curable resin, an ultraviolet curable acrylate resin (hereinafter also referred to as monofunctional acrylate) is preferable. Monofunctional acrylates include isobornyl acrylate, dicyclopentenyloxyethyl methacrylate, 2-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, Examples include lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and cyclohexyl acrylate. Monofunctional acrylates can be obtained from Shin-Nakamura Chemical Co., Ltd., Osaka Organic Chemical Co., Ltd., Hitachi Chemical Co., Ltd., etc.

  In addition to the monofunctional acrylate, polyurethane acrylate, polyisoprene acrylate, or polyfunctional acrylate described later may be used. These acrylates may be used alone or in combination of two or more.

  The actinic radiation curable resin composition preferably contains a photopolymerization initiator to accelerate curing. The amount of the photopolymerization initiator is preferably contained in a mass ratio of photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100.

  Examples of the photopolymerization initiator include alkylphenone, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not limited thereto. Specific examples of the photopolymerization initiator include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl. } -2-Methyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone and the like, and as commercially available products, for example, Irgacure 184, Irgacure 127, Irgacure 907 manufactured by BASF Japan Ltd., Irgacure 651, DAROCUR 1173 and the like are preferable examples. Furthermore, since the protection unit 30 is often provided with a function of cutting the ultraviolet region from the viewpoint of protecting the image display panel 102 from ultraviolet rays, the photopolymerization initiator that can be cured even in the visible light region is used. It is also preferable to use an agent (for example, trade name SpeedCureTPO, manufactured by Nippon Shibel Hegner Co., Ltd.).

  Furthermore, it is also preferable to use a thermal polymerization initiator for acceleration of curing. Specifically, an organic peroxide that acts as an initiator by heat can be used. Examples of the organic peroxide include C12H24O3 (manufactured by Nippon Oil & Fats Co., Ltd., trade name: Perbutyl O and Nippon Oil & Fats Co., Ltd., trade name: Parroyl TCP). The thermal polymerization initiator is preferably contained in the actinic radiation curable resin at a mass ratio of thermal polymerization initiator: active radiation curable resin = 10: 100 to 0.01: 100.

  The actinic radiation curable resin composition preferably also contains one or more polymers such as a terpene hydrogenated resin and a butadiene polymer.

In the active ray curable resin composition, a resin cured layer is formed by irradiation with light such as ultraviolet rays. As the ultraviolet light source, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. Moreover, although irradiation conditions differ with each lamp | ramp, the irradiation amount of an active ray is 100-3000mJ / cm < ² > normally, Preferably it is 100-1500mJ / cm < ² >. You may heat-process as needed. Although the temperature of heat processing is not specifically limited, From a viewpoint of preventing the deformation | transformation etc. of a plastic material part, 60 to 100 degreeC is preferable. As a heating method, for example, as shown in FIG. 2 (II), after the protective portion 103 is disposed on the spacer 90 of the base portion 20 and the curable resin composition 110 and the functional layer of the polarizing plate 1 are adhered, A method of heating the entire product by placing it on a heating stage. Alternatively, a method of arranging a heater in the formation region of the light-shielding part 50 around the liquid crystal display panel 102 may be mentioned, but the method is not limited thereto.

  The curable resin composition may contain a solvent, a conductive agent or a surfactant described in the functional layer, if necessary. As a method of forming the cured resin layer, after dropping the curable resin composition onto the protective part 103, the base 20 is overlapped on the opposite side and formed by light irradiation, the curable resin composition is applied to the protective part 103 or the base 20 It coats by the below-mentioned coating method on the optical film which has a functional layer, and after that, the protection part 103 and the base 20 are piled up facing each other, the method of forming by light irradiation, the protection part 103 and the base 20 are piled up facing each other. And a method of filling the curable resin composition between them and forming it by light irradiation.

<Optical film>
Next, an optical film having a functional layer, which is another feature of the present invention, will be described.

  An example of the structure of the polarizing plate 1 using the optical film according to the present invention is shown in FIG.

  FIG. 3A is a cross-sectional view of the polarizing plate 1 using the optical film according to the present invention, and includes the optical film 10 according to the present invention having the film substrate 11 and the functional layer 12 on the polarizing film 13. The protective film 14 and the adhesive layer 15 for adhesion to the liquid crystal panel are formed on the opposite side.

  FIG. 3B is a perspective view of the functional layer 12, and the irregularly shaped protrusions 16 are irregularly arranged.

That is, the optical film according to the present invention is provided with a functional layer on a film substrate, the functional layer has a protrusion shape, and the protrusion shape is irregular and irregular on the film substrate. The functional layer has an arithmetic average roughness Ra (JIS B0601: 1994) of 25 to 300 nm, and haze due to internal scattering of the functional layer is 0 to 1.0%. By setting the storage elastic modulus (25 ° C.) of the optical film and the cured resin layer to 1 × 10 ⁷ Pa or less, the adhesion area between the functional layer and the cured resin layer can be suitably obtained even after the weather resistance test. . Furthermore, since haze caused by internal scattering is minimized to 0 to 1.0%, a decrease in contrast due to light scattering can be sufficiently suppressed, and high contrast and excellent visibility can be provided.

(Surface shape)
First, the surface shape of the functional layer will be described. The “irregularly shaped protrusion” of the functional layer of the optical film of the present invention is not a protrusion shape having a regular shape obtained by embossing with a mold having surface irregularities on the functional layer. This refers to protrusions of various shapes that are not defined in shape or size. Although not limited thereto, for example, protrusions having different widths and heights such as (a) and (b) shown in FIG. 4 are exemplified as irregularly shaped protrusions. In addition, “irregular arrangement” means that the irregularly shaped protrusions are not regularly arranged (for example, at regular intervals), but are irregularly arranged at random intervals, It may be isotropic or anisotropic.

  The optical film of the present invention has a haze (hereinafter also referred to as internal haze) due to internal scattering of the functional layer of 0 to 1.0%, preferably 0.6 to 1.0%. The internal haze can be measured by the following procedure. A few drops of silicone oil are dropped on the front and back surfaces of the optical film, and sandwiched between two glass plates (micro slide glass product number S9111, manufactured by MATSANAMI) with a thickness of 1 mm. The optical film sandwiched between the front and back glass is optically brought into intimate contact with two glass plates, and haze (Ha) is measured according to JIS-K7136 in this state. Next, several drops of silicone oil are dropped between two glass plates and sandwiched to measure glass haze (Hb). The internal haze (Hi) can be calculated by subtracting the glass haze (Hb) from the haze (Ha) between which the optical film is sandwiched with glass. Moreover, it is preferable that surface haze (the haze resulting from the surface scattering of a film) is 0.5 to 20%. The surface haze is obtained by subtracting the internal haze from the total haze. The total haze is preferably 0.5% to 20%.

  Further, the ratio of the surface haze to the internal haze (surface haze / internal haze) is preferably 3.5 or more from the viewpoint of the objective effect. More preferably, it is 3.5 or more and 100 or less.

  The optical film of the present invention has an arithmetic average roughness Ra (JIS B0601: 1994) of the functional layer of 25 to 300 nm. The arithmetic average roughness Ra is more preferably 25 to 130 nm, and particularly preferably 65 to 130 nm. In order to obtain the arithmetic average roughness Ra within the above range, the height of the protrusion shape is preferably 20 nm to 4 μm. The width of the protrusion shape is 50 nm to 300 μm, preferably 50 nm to 100 μm. The height and width of the protrusion shape can be obtained from cross-sectional observation.

  In order to make it easier to understand, FIG. 4 shows an explanatory view of the protrusion. As shown in FIG. 4, the center line a is drawn on the cross-sectional observation image, and the distance between two intersections of the lines b and c and the center line a forming the mountain ridge is defined as the protrusion size width t and did. Further, the distance from the summit to the center line a is obtained as the height h of the protrusion size.

  Further, from the viewpoint of easily obtaining the objective effect, the 10-point average roughness Rz of the functional layer of the optical film of the present invention is preferably not more than 10 times the centerline average roughness Ra, and the average mountain valley distance Sm is preferably 5 to 150 μm. More preferably, it is 20 to 100 μm, the standard deviation of the height of the convex part from the deepest part of the unevenness is 0.5 μm or less, the standard deviation of the average mountain valley distance Sm based on the center line is 20 μm or less, and the inclination angle is 0 to 5 degrees. The surface is preferably 10% or more. Arithmetic average roughness Ra, Sm, Rz is a value measured with an optical interference type surface roughness meter (for example, RST / PLUS, manufactured by WYKO) according to JIS B0601: 1994. The kurtosis (Rku) of the functional layer is preferably 3 or less. The kurtosis (Rku) is a parameter that defines the shape of the convex portion of the concavo-convex shape. The larger the kurtosis (Rku) value, the more the shape of the convex portion of the concavo-convex shape is pointed like a needle. Shape. When the kurtosis (Rku) exceeds 3, it is difficult to obtain the target effect. More preferably, it is 1.5-2.8.

  Further, the absolute value of the surface distortion (Rsk) is preferably 1 or less. The skewness (Rsk) is a parameter indicating the ratio of the convex portion to the concave portion with respect to the average surface of the concavo-convex shape. If the concavo-convex shape has a large number of convex portions with respect to the average surface, a positively large value is obtained. If there are many concave parts with respect to the surface, the value becomes negatively large. When the absolute value of the skewness (Rsk) exceeds 1, the intended effect is difficult to obtain. The absolute value of the skewness (Rsk) is preferably 0.01 to 0.5. The kurtosis (Rku) and the skewness (Rsk) can also be measured using the optical interference surface roughness meter.

  Although the details of the functional layer will be described later, the surface effect having the above characteristics makes it easy to obtain the intended effect, and the surface shape is, for example, a rate-decreasing drying section in the drying process of the functional layer coating composition. It can be obtained by a method of controlling the processing temperature at a high temperature, generating convection of the resin film, creating a non-uniform state on the surface of the functional layer, curing in this non-uniform surface state, and forming a coating film. it can. Next, details of the functional layer according to the present invention will be described.

(Functional layer)
The functional layer according to the present invention contains an actinic radiation curable resin, that is, a resin that is cured through a crosslinking reaction when irradiated with actinic rays (also referred to as active energy rays) such as ultraviolet rays and electron beams. The layer is preferably

  As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the actinic radiation curable resin layer is cured by irradiation with actinic radiation such as ultraviolet rays or electron beams. It is formed.

  Typical examples of the actinic radiation curable resin include an ultraviolet curable resin, an electron beam curable resin, and the like, but a resin that is cured by ultraviolet irradiation is preferable from the viewpoint of point mechanical film strength that easily achieves the intended effect.

  Examples of the ultraviolet curable resin include an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet ray. A curable epoxy resin or the like is preferably used. Of these, ultraviolet curable acrylate resins are preferred.

  As the ultraviolet curable acrylate resin, a polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or methacryloyloxy groups in the molecule. Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tri / tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerol triacrylate relay , Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol di Methacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pen Pentaerythritol tetramethacrylate, glycerol trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexa methacrylate, etc. isocyanurate derivatives of the active energy ray-curable are preferably exemplified. The active energy ray-curable isocyanurate derivative is not particularly limited as long as it is a compound having a structure in which one or more ethylenically unsaturated groups are bonded to the isocyanuric acid skeleton, but three or more in the same molecule. A compound having an ethylenically unsaturated group and one or more isocyanurate rings is preferred. These commercial products are Adekaoptomer KR / BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (manufactured by ADEKA); Seika Beam PHC2210 (S), PHC X-9 (K-3), PHC2213, DP-10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (manufactured by Dainichi Seika Kogyo Co., Ltd.); KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (manufactured by Daicel UC Corporation); RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC-5120, RC-51 2, RC-5152, RC-5171, RC-5180, RC-5181 (manufactured by DIC Corporation); Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (manufactured by Sanyo Chemical Industries); SP-1509, SP-1507 (manufactured by Showa Polymer Co., Ltd.); RCC-15C (manufactured by Grace Japan), Aronix M-6100, M- 8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (manufactured by Toagosei Co., Ltd.), NK-ester A-TMM-3L, NK-ester AD-TMP, NK-ester ATM-35E, NK hard B-420, NK ester A-DOG, NK ester A-IBD-2E, A-9300, A-9300-1CL (Shin Nakamura Chemical Co., Ltd.), PE-3A (Kyoeisha Chemical Co., Ltd.), etc. are mentioned.

  In addition to the polyfunctional acrylate, the functional layer may contain a monofunctional acrylate described in the resin cured layer. When using a monofunctional acrylate, it is preferable to contain polyfunctional acrylate: monofunctional acrylate = 80: 20 to 99: 2 in terms of the mass ratio of polyfunctional acrylate and monofunctional acrylate.

  Actinic radiation curable resins other than the polyfunctional acrylates and monofunctional acrylates described above may be used singly or in combination. The viscosity at 25 ° C. of the actinic radiation curable resin alone or in combination of two or more is preferably 30 mPa · s or more and 3000 mPa · s or less, and more preferably 30 mPa · s or more and 2000 mPa · s or less.

  By using such a low-viscosity resin, sufficient fluidity of the resin composition can be obtained in the drying step, so that a protrusion shape is easily formed in the functional layer. Moreover, if it is an actinic radiation curable resin having a viscosity of 30 mPa · s or more, sufficient curability is obtained, and if it is an actinic radiation curable resin having a viscosity of 3000 mPa · s or less, the resin composition is sufficient in the drying step. Therefore, it is easy to form an uneven shape in the functional layer. The viscosity is a value measured using a B-type viscometer at 25 ° C. Examples of the low viscosity resin include glycerin triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

  The functional layer preferably contains a photopolymerization initiator in order to accelerate the curing of the actinic radiation curable resin. The amount of the photopolymerization initiator is preferably contained in a mass ratio of photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100. Specific examples of the photopolymerization initiator include alkylphenone series, acetophenone, benzophenone, hydroxybenzophenone, Michler ketone, α-amyloxime ester, thioxanthone and the like, and derivatives thereof. In particular, it is not limited to these. A commercial item may be used for such a photoinitiator, for example, Irgacure 184, Irgacure 907, Irgacure 651, etc. by BASF Japan Ltd. are mentioned as a preferable illustration.

  It is preferable that the functional layer does not substantially contain fine particles such as inorganic fine particles and organic fine particles because the objective effect of the present invention is difficult to obtain, and the brightness and contrast are lowered due to an increase in internal haze.

  In addition, since the functional layer of the present invention contains substantially no non-reactive polymer and the above characteristics are obtained, the functional layer of the optical film of the present invention contains substantially no non-reactive polymer. It is preferable not to contain it.

  In addition, the functional layer preferably contains a compound having an HLB value of 3 to 18 from the viewpoint that the objective effect of the present invention can be obtained satisfactorily. Next, a compound having an HLB value of 3 to 18 will be described. The HLB value is Hydrophile-Lipophile-Balance, hydrophilic-lipophilic-balance, and is a value indicating the hydrophilicity or lipophilicity of a compound. The smaller the HLB value, the higher the lipophilicity, and the higher the value, the higher the hydrophilicity. The HLB value can be obtained by the following calculation formula.

HLB = 7 + 11.7Log (Mw / Mo)
In the formula, Mw represents the molecular weight of the hydrophilic group, Mo represents the molecular weight of the lipophilic group, and Mw + Mo = M (molecular weight of the compound). Alternatively, according to the Griffin method, HLB value = 20 × total formula weight of hydrophilic part / molecular weight (J. Soc. Cosmetic Chem., 5 (1954), 294) and the like. Specific examples of the compound having an HLB value of 3 to 18 are listed below, but the present invention is not limited thereto. Figures in parentheses indicate HLB values.

Made by Kao Corporation: Emulgen 102KG (6.3), Emulgen 103 (8.1), Emulgen 104P (9.6), Emulgen 105 (9.7), Emulgen 106 (10.5), Emulgen 108 (12. 1), Emulgen 109P (13.6), Emulgen 120 (15.3), Emulgen 123P (16.9), Emulgen 147 (16.3), Emulgen 210P (10.7), Emulgen 220 (14.2) , Emulgen 306P (9.4), Emulgen 320P (13.9), Emulgen 404 (8.8), Emulgen 408 (10.0), Emulgen 409PV (12.0), Emulgen 420 (13.6), Emulgen 430 (16.2), Emulgen 705 (10.5), Emulgen 707 (12.1), Emulgen 7 9 (13.3), Emulgen 1108 (13.5), Emulgen 1118S-70 (16.4), Emulgen 1135S-70 (17.9), Emulgen 2020G-HA (13.0), Emulgen 2025G (15. 7), Emulgen LS-106 (12.5), Emulgen LS-110 (13.4), Emulgen LS-114 (14.0), Emulgen MS-110 (12.7), Emulgen A-60 (12. 8), Emulgen A-90 (14.5), Emulgen A-500 (18.0), Emulgen B-66 (13.2), Latemul PD-420 (12.6), Latemul PD-430 (14. 4), Latemul PD-430S (14.4), Latemuru PD-450 (16.2), Rhedol SP-L10 (8.6), Rhedol SP- 10 (6.7), Rhedol SP-S10V (4.7), Rhedol SP-S20 (4.4), Rhedol SP-O10V (4.3), Rheodor Super SP-L10 (8.6), Rheodor AS10V (4.7), Rhedol AO-10V (4.3), Rheodor AO-15V (3.7), Emazole L-10V (8.6), Emazole P-10V (6.7), Emazole S- 10V (4.7), Emazole O-10V (4.3), Rheodor TW-L120 (16.7), Rhedol TW-L106 (13.3), Rheodor TW-P120 (15.6), Rhedol TW- S120V (14.9), Rheodor TW-S106V (9.6), Rheodor TW-S320V (10.5), Rheodor TW-O120V (15.0), R Odol TW-O106V (10.0), Rheodor TW-O320V (11.0), Rheodor Super TW-L120 (16.7), Rheodor 430V (10.5), Rheodor 440V (11.8), Rheodor 460V (13.8), Rhedol MS-60 (3.5), Rhedol MS-165V (11.0), Excel T-95 (3.8), Excel VS-95 (3.8), Excel O-95R (3.5), Excel 200 (3.5), Excel 122V (3.5), Emanon 1112 (13.7), Emanon 4110 (11.6), Emanon CH-25 (10.7), Emanon CH -40 (12.5), Emanon CH-60 (K) (14.0), Emanon CH-80 (15.0), Amit 102 (6.3), A 105 (9.8), Amite 105A (10.8), Amite 302 (5.1), Amite 320 (15.4), Aminone PK-02S (5.5), Aminone L-02 (5. 8),
Nissin Chemical Industry Co., Ltd .: Surfinol 104E (4), Surfinol 104H (4), Surfinol 104A (4), Surfinol 104BC (4), Surfinol 104DPM (4), Surfinol 104PA (4), Surfinol 104PG-50 (4), Surfinol 104S (4), Surfinol 420 (4), Surfinol 440 (8), Surfinol 465 (13), Surfinol 485 (17), Surfinol SE (6) Surfinol SE-F (6), Surfinol 61 (6), Surfinol 604 (8), Surfinol 2502 (8), Surfinol 82 (4), Surfinol DF110D (3), Surfinol CT111 (8 To 11), Surfinol CT121 (11- 5), Surfinol CT136 (13), Surfinol TG (9), Surfinol GA (13), Orphine STG (9-10), Orphin E1004 (7-9), Orphin E1010 (13-14), Shin-Etsu Chemical Industrial Co., Ltd .: X-22-4272 (7), X-22-6266 (8), KF-351 (12), KF-352 (7), KF-353 (10), KF-354L (16) , KF-355A (12), KF-615A (10), KF-945 (4), KF-618 (11), KF-6011 (12), KF-6015 (4), KF-6004 (5)
The compound having an HLB value of 3 to 18 is preferably used in an amount of 0.005 mass% or more and less than 10 mass% in the solid content of the functional layer coating composition. Two or more of these compounds having an HLB value of 3 to 18 may be used in combination. The functional layer may contain a fluorine-siloxane graft polymer from the viewpoint of coatability.

  The fluorine-siloxane graft polymer refers to a copolymer polymer obtained by grafting polysiloxane containing siloxane and / or organosiloxane alone and / or organopolysiloxane to at least a fluorine-based resin. Examples of such a fluorine-siloxane graft polymer include ZX-022H, ZX-007C, ZX-049, and ZX-047-D manufactured by Fuji Kasei Kogyo Co., Ltd. as commercially available products. Moreover, it is preferable to add these components in 0.005-10 mass% with respect to the solid content component in a coating liquid.

  The functional layer may contain a conductive agent in order to impart antistatic properties. Preferred conductive agents include metal oxide particles or π-conjugated conductive polymers. An ionic liquid is also preferably used as the conductive compound.

  The functional layer is a functional layer coating composition obtained by diluting the components for forming the functional layer described above with a solvent or the like, and the functional layer coating composition is coated on a film substrate by the following method, dried, It can be formed by curing and providing a functional layer. As the solvent, ketone (methyl ethyl ketone, acetone, etc.) and / or acetate ester (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohol (methanol, butanol), propylene glycol monomethyl ether, cyclohexone, methyl isobutyl ketone, etc. are preferable. .

  The coating amount of the functional layer is suitably from 0.1 to 30 μm, preferably from 0.1 to 20 μm, as the wet film thickness. The dry film thickness is an average film thickness of 50 nm to 10 μm, preferably 100 nm to 6 μm. As a method for applying the functional layer, a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, an ink jet method, or an applicator can be used. Using these coating methods, the functional layer coating composition is applied, dried after application, irradiated with actinic radiation (also referred to as UV curing treatment), and if necessary, formed by heat treatment after UV curing. it can.

  Moreover, you may perform active ray irradiation, after forming a functional layer and laminating | stacking a cured resin layer. Further, after applying and drying the functional layer, a cured resin layer may be laminated, and then irradiated with actinic radiation.

Further, for the purpose of improving the interlayer adhesion between the functional layer and the cured resin layer, the cured resin layer is preferably cured in a half-cured state. The half-cured state (semi-cured state) refers to a state that is cured at least to the extent that there is no tack on the coating surface. As a light source for the UV curing treatment for curing in the half-cured state, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 1 to 200 mJ / cm ² , preferably 10 to 100 mJ / cm ² .

  Drying is preferably performed by high-temperature treatment in which the temperature in the decreasing rate drying section is 95 ° C. or higher. More preferably, the temperature in the decreasing rate drying section is 95 ° C or higher and 150 ° C or lower. By setting the temperature of the rate-decreasing drying section to a high temperature treatment, convection occurs in the coating resin during the formation of the functional layer. As a result, irregular surface irregularities are likely to appear, and the arithmetic average roughness Ra It is preferable because it is easy to control.

  In general, it is known that the drying process changes from a constant state to a gradually decreasing state when drying starts. The decreasing section is called the decreasing rate drying section. In the constant rate drying section, the amount of heat flowing in is all consumed for solvent evaporation on the coating film surface, and when the solvent on the coating film surface decreases, the evaporation surface moves from the surface to the inside and enters the decreasing rate drying section. Thereafter, the temperature of the coating film surface rises and approaches the hot air temperature, so that the temperature of the actinic radiation curable resin composition rises, the resin viscosity decreases, and the fluidity increases.

  When irradiating actinic radiation, it is preferably performed while applying tension in the film transport direction, and more preferably while applying tension in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying tension is not particularly limited, and tension may be applied in the transport direction on the back roll, or tension may be applied in the width direction or biaxial direction by a tenter. Thereby, a film having further excellent flatness can be obtained.

  A functional layer may contain the ultraviolet absorber mentioned later. As a structure of the film in the case of containing the ultraviolet absorber, it is preferable that the functional layer is composed of two or more layers and the antiglare layer in contact with the film substrate contains the ultraviolet absorber. The content of the ultraviolet absorber is preferably a mass ratio, and the ultraviolet absorber: functional layer constituting resin = 0.01: 100 to 10: 100.

  Moreover, when providing two or more functional layers, it is preferable that the film thickness of the functional layer which contact | connects a film base material is the range of 0.05-2 micrometers. Two or more layers may be formed as a simultaneous multilayer. The simultaneous multi-layering is to form a functional layer by applying two or more anti-glare layers on a base material without going through a drying step. In order to laminate the second functional layer on the first anti-glare layer without a drying step, the second functional layer is laminated on a wet die by using an extrusion coater or by using a slot die having a plurality of slits. Can be done.

  In the optical film according to the present invention, the pencil hardness which is an index of hardness is preferably HB or more, more preferably H or more. If it is more than H, it will be hard to be damaged in the polarizing plate formation process of a liquid crystal display device. Pencil hardness is specified by JIS K5400 using a test pencil specified by JIS S 6006 under the condition of a weight of 500 g after the prepared optical film is conditioned at a temperature of 23 ° C. and a relative humidity of 55% for 2 hours or more. It is a value measured according to the pencil hardness evaluation method. Next, the film substrate will be described.

<Film base>
The film base according to the present invention is preferably easy to manufacture, easily adheres to the functional layer, optically transparent, and isotropic. Moreover, in this invention, a film base material is used as a protective film of a polarizing plate.

  Any film substrate having the above properties may be used, for example, cellulose ester-based films such as triacetyl cellulose film, cellulose acetate propionate film, cellulose diacetate film, and cellulose acetate butyrate film, polyethylene terephthalate, polyethylene Polyester film such as naphthalate, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, Syndiotactic polystyrene film, norbornene resin film, polymethylpentene Irumu, polyether ketone film, polyether ketone imide film, a polyamide film, a fluorine resin film, nylon film, can be used cycloolefin polymer film, a polymethyl methacrylate film or an acrylic film or the like.

  Among these, cellulose ester films (for example, Konica Minoltak KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UE, KC4UE, and KC12UR (above, manufactured by Konica Minolta Opto, Polycarbonate) An olefin polymer film and a polyester film are preferable, and in the present invention, a cellulose ester film is preferable from the viewpoint that the protruding shape of the functional layer is easily obtained, productivity, and cost.

  The refractive index of the film substrate is preferably 1.30 to 1.70, and more preferably 1.40 to 1.65. The refractive index is measured by the method of JIS K7142 using an Atpe refractometer 2T.

  Further, the tan δ measured by changing the temperature from 25 ° C. to 210 ° C. at a humidity of 55% RH in the width direction of the film has the following relationship. Is preferable from the viewpoint of exhibiting good.

0.5 ≧ tan δ-40 / tan δ peak ≧ 0.24
Here, tan δ peak is the maximum value obtained by measuring the tan δ value by changing the temperature from 25 ° C. to 210 ° C., and tan δ-40 is the value of tan δ at a temperature of −40 ° C. when tan δ peak is indicated.

  By setting the balance of the storage elastic modulus and the loss elastic modulus with respect to the tan δ in the film width direction of the film base material, that is, the temperature, within the above range, the object effect of the present invention is better exhibited. The tan δ can be measured, for example, by using a sample that has been conditioned for 24 hours in an atmosphere of 23 ° C. and 55% RH and increasing the humidity at 55% RH under the following conditions or setting the temperature. it can.

Measuring device: RSA III manufactured by TI Instruments
Sample: width 5 mm, length 50 mm (gap set to 20 mm)
Measurement conditions: Tensile mode Measurement temperature: 25-210 ° C or -40 ° C
Temperature rising condition: 5 ° C / min
Frequency: 1Hz
(Cellulose ester film)
Next, it demonstrates in detail about a cellulose-ester film preferable as a film base material.

  The cellulose ester film is not particularly limited as long as it has the above characteristics, but the cellulose ester resin (hereinafter also referred to as cellulose ester) is preferably a lower fatty acid ester of cellulose. The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. For example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate and the like, and JP-A-10-45804 Nos. 08-231761, U.S. Pat. No. 2,319,052, etc., mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate can be used.

  Among the above descriptions, the lower fatty acid esters of cellulose that are particularly preferably used are cellulose diacetate, cellulose triacetate, and cellulose acetate propionate. These cellulose esters can be used alone or in combination.

  Cellulose diacetate preferably has an average degree of acetylation (bound acetic acid amount) of 51.0% to 56.0%. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804. Moreover, as a commercial item, Daicel Corporation L20, L30, L40, L50, Caman-3, Ca398-6, Ca398-10, Ca398-30, Ca394-60S of Eastman Chemical Co., Ltd. are mentioned.

  The cellulose triacetate preferably has an average degree of acetylation (bound acetic acid amount) of 54.0 to 62.5%, and more preferably cellulose triacetate having an average degree of acetylation of 58.0 to 62.5%. is there.

  When the average degree of acetylation is small, the dimensional change is large, and the polarization degree of the polarizing plate is lowered. When the average degree of acetylation is large, the solubility in a solvent is lowered and the productivity is lowered.

  The cellulose triacetate has a degree of acetyl group substitution of 2.80 to 2.95, a number average molecular weight (Mn) of 125,000 or more and less than 155000, a weight average molecular weight (Mw) of 265,000 or more and less than 310,000, Mw / Mn. Triacetate A having a acetyl group substitution degree of 2.75 to 2.90, a number average molecular weight (Mn) of 155,000 or more and less than 180,000, Mw of 290000 or more and less than 360,000, Mw / Mn preferably contains cellulose triacetate B which is 1.8 to 2.0.

  Further, when cellulose triacetate A and cellulose triacetate B are used in combination, it is preferable that the mass ratio is in the range of cellulose triacetate A: cellulose triacetate B = 100: 0 to 20:80. Preferred cellulose esters other than cellulose triacetate have an acyl group having 2 to 4 carbon atoms as a substituent, the substitution degree of acetyl group is X, and the substitution degree of propionyl group or butyryl group is Y, It is a cellulose ester containing the cellulose ester which satisfy | fills (I) and (II) simultaneously.

Formula (I) 2.6 ≦ X + Y ≦ 3.0
Formula (II) 0 ≦ X ≦ 2.5
In particular, cellulose acetate propionate is preferably used, and among them, 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9 are preferable.

  The number average molecular weight (Mn) and molecular weight distribution (Mw) of the cellulose ester can be measured using high performance liquid chromatography. The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G
(Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation)
A calibration curve with 13 samples from Mw = 100000 to 500 was used. The 13 samples are preferably used at approximately equal intervals.

(Cellulose ester resin / thermoplastic acrylic resin-containing film)
The film substrate contains a thermoplastic acrylic resin and a cellulose ester resin, and the mass ratio of the thermoplastic acrylic resin to the cellulose ester resin is thermoplastic acrylic resin: cellulose ester resin = 95: 5 to 50:50. You may use the film which is.

  Acrylic resin also includes methacrylic resin. Although it does not restrict | limit especially as an acrylic resin, What consists of 50-99 mass% of methyl methacrylate units and 1-50 mass% of other monomer units copolymerizable with this is preferable. Other monomers that can be copolymerized include alkyl methacrylates having 2 to 18 carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, acrylic acid, methacrylic acid, and the like. Unsaturated group-containing divalent carboxylic acids such as saturated acid, maleic acid, fumaric acid and itaconic acid, aromatic vinyl compounds such as styrene and α-methylstyrene, α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, Maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride and the like can be mentioned, and these can be used alone or in combination of two or more monomers.

  Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer. n-Butyl acrylate is particularly preferably used. Moreover, it is preferable that a weight average molecular weight (Mw) is 80000-500000, More preferably, it exists in the range of 110000-500000.

  The weight average molecular weight of the acrylic resin can be measured by gel permeation chromatography including the measurement conditions. There is no restriction | limiting in particular as a manufacturing method of an acrylic resin, You may use any well-known methods, such as suspension polymerization, emulsion polymerization, block polymerization, or solution polymerization. Here, as a polymerization initiator, a normal peroxide type and an azo type can be used, and a redox type can also be used. Regarding the polymerization temperature, suspension or emulsion polymerization may be performed at 30 to 100 ° C, and bulk or solution polymerization may be performed at 80 to 160 ° C. In order to control the reduced viscosity of the obtained copolymer, polymerization can be carried out using alkyl mercaptan or the like as a chain transfer agent. Commercial products can also be used. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dianal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Denki Kagaku Kogyo Co., Ltd.) and the like can be mentioned. . Two or more acrylic resins can be used in combination. Further, as the acrylic resin, a graft copolymer obtained by grafting a (meth) acrylic resin to a copolymer of (meth) acrylic rubber and an aromatic vinyl compound described in JP-A-2009-84574 may be used. Good. In the graft copolymer, a copolymer of (meth) acrylic rubber and an aromatic vinyl compound forms a core, and the (meth) acrylic resin forms a shell around the copolymer. -It is preferably a shell-type graft copolymer.

  The total mass of the acrylic resin and cellulose ester resin in the film substrate is preferably 55% by mass or more of the film substrate, more preferably 60% by mass or more, and particularly preferably 70% by mass or more. The film substrate may contain a resin other than thermoplastic acrylic resin and cellulose ester resin and additives.

(Acrylic particles)
The film base material may contain acrylic particles because it is excellent in improving brittleness. An acrylic particle represents the acrylic component which exists in the state of particle | grains (it is also called an incompatible state) in the film base material containing the said thermoplastic acrylic resin and cellulose-ester resin in a compatible state.

  The acrylic particles are not particularly limited, but are preferably multi-layered acrylic granular composites. Examples of commercially available acrylic granular composites that are multi-layer structured polymers include, for example, “Metablene” manufactured by Mitsubishi Rayon Co., “Kaneace” manufactured by Kaneka Chemical Co., Ltd., “Paralloid” manufactured by Kureha Chemical Co., Ltd., Rohm and “Acryloid” manufactured by Haas, “Staffyroid” manufactured by Ganz Kasei Kogyo Co., Ltd., “Parapet SA” manufactured by Kuraray Co., Ltd., and the like can be used, and these can be used alone or in combination of two or more. When acrylic particles are added to the film substrate, it is preferable that the refractive index of the mixture of the acrylic resin and the cellulose ester resin is close to the refractive index of the acrylic particles in order to obtain a highly transparent film. Specifically, the refractive index difference between the acrylic particles and the acrylic resin is preferably 0.05 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less.

  The acrylic fine particles are in the range of acrylic fine particles: acrylic resin and cellulose ester resin total mass = 0.5: 100 to 30: 100 with respect to the total mass of the acrylic resin and cellulose ester resin constituting the film. By containing, it is preferable from the point that an objective effect is exhibited more preferable, More preferably, it is the range of 1.0: 100-15: 100 of acrylic fine particles: total mass of acrylic resin and cellulose-ester resin.

(Fine particles)
In order to improve the handleability, the film substrate according to the present embodiment has, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, silica It is preferable to contain matting agents such as inorganic fine particles such as aluminum oxide, magnesium silicate, and calcium phosphate, and a crosslinked polymer. Among these, silicon dioxide is preferably used because it can reduce the haze of the film.

  The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm.

  It is preferable to cast the dope containing fine particles so as to be in direct contact with the casting support because a film having high slip properties and low haze can be obtained.

  Silicon dioxide is commercially available under the trade names of, for example, Aerosil 200V, Aerosil R812, Aerosil R972V (above, Nippon Aerosil Co., Ltd.), and these can also be used.

(Other additives)
In order to improve the fluidity and flexibility of the composition, a plasticizer can be used in combination with the film substrate. Examples of the plasticizer include phthalate ester, fatty acid ester, trimellitic ester, phosphate ester, polyester, and epoxy. Of these, polyester and phthalate plasticizers are preferably used. Polyester plasticizers are superior in non-migration and extraction resistance compared to phthalate ester plasticizers such as dioctyl phthalate. It can be applied to a wide range of uses by selecting or using these plasticizers according to the use.

  The polyester plasticizer is a reaction product of a monovalent or tetravalent carboxylic acid and a monovalent or hexavalent alcohol, and is mainly obtained by reacting a divalent carboxylic acid with a glycol. . Representative divalent carboxylic acids include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, sebacic acid and the like. The polyester plasticizer is preferably an aromatic terminal ester plasticizer. The aromatic terminal ester plasticizer is preferably an ester compound having a structure obtained by reacting phthalic acid, adipic acid, at least one benzene monocarboxylic acid, and at least one alkylene glycol having 2 to 12 carbon atoms. As long as it has an adipic acid residue and a phthalic acid residue as the structure of such a compound, when an ester compound is produced, it may be reacted as an acid anhydride or esterified product of dicarboxylic acid.

  Examples of the benzene monocarboxylic acid component include benzoic acid, para-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid and the like. Most preferred is benzoic acid. Moreover, these can be used as a 1 type, or 2 or more types of mixture, respectively.

  Examples of the alkylene glycol component having 2 to 12 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1, 3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol 1 , 6-hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1,3-hexanediol, - methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecane diol. Among these, 1,2-propylene glycol is particularly preferable. These glycols may be used as one kind or a mixture of two or more kinds. The aromatic terminal ester plasticizer may be of an oligoester type or a polyester type, and the molecular weight is preferably in the range of 100 to 10,000, but is preferably in the range of 350 to 3000. The acid value is 1.5 mgKOH / g or less, the hydroxyl value is 25 mgKOH / g or less, more preferably the acid value is 0.5 mgKOH / g or less, and the hydroxyl value is 15 mgKOH / g or less.

  The plasticizer is preferably added in an amount of 0.5 to 30 parts by mass with respect to 100 parts by mass of the resin forming the film substrate.

  Specific examples of the aromatic terminal ester plasticizer include, but are not limited to, the following compounds.

  Further, the film substrate may contain a sugar ester compound. The sugar ester compound is a compound obtained by esterifying all or part of the OH group of a sugar such as the following monosaccharide, disaccharide, trisaccharide or oligosaccharide, specifically, a compound represented by the general formula (1) Etc.

(In the formula, R _{1 to} R ₈ represent a substituted or unsubstituted alkylcarbonyl group or a substituted or unsubstituted arylcarbonyl group, and R _{1 to} R ₈ may be the same or different. Good.)
Although the compound shown by General formula (1) below is shown more concretely (compound 1-1-compound 1-23), it is not limited to these.

  It is preferable to add 0.5-30 mass parts of sugar ester compounds with respect to 100 mass parts of resin which forms a film base material.

  The film substrate preferably contains an ultraviolet absorber, and examples of the ultraviolet absorber used include benzotriazole-based, 2-hydroxybenzophenone-based or salicylic acid phenyl ester-based ones. For example, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3 Triazoles such as 5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone And benzophenones.

  Among UV absorbers, UV absorbers with a molecular weight of 400 or more are difficult to volatilize at high boiling points and are difficult to disperse even during high temperature molding, so that the weather resistance can be effectively improved with a relatively small amount of addition. Can do.

  Examples of the ultraviolet absorber having a molecular weight of 400 or more include 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2-methylenebis [4- (1, 1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol], bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis ( Hindered amines such as 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonic acid Bis (1,2,2,6,6-pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl L] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine and the like, hindered phenol and hindered amine A hybrid system having both structures can be mentioned, and these can be used alone or in combination of two or more. Among these, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole and 2,2-methylenebis [4- (1,1,3,3- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.

  Commercially available products may be used. For example, TINUVIN such as TINUVIN 109, TINUVIN 171, TINUVIN 234, TINUVIN 326, TINUVIN 327, TINUVIN 328, and TINUVIN 928 manufactured by BASF Japan Ltd. can be preferably used.

  Various antioxidants can also be added to the film substrate in order to improve the thermal decomposability and thermal colorability during molding. An antistatic agent can be added to impart antistatic performance to the film substrate.

  A flame retardant acrylic resin composition containing a phosphorus flame retardant may be used for the film substrate. Phosphorus flame retardants used here include red phosphorus, triaryl phosphate ester, diaryl phosphate ester, monoaryl phosphate ester, aryl phosphonate compound, aryl phosphine oxide compound, condensed aryl phosphate ester, halogenated alkyl phosphorus. Examples thereof include one or a mixture of two or more selected from acid esters, halogen-containing condensed phosphates, halogen-containing condensed phosphonates, halogen-containing phosphites, and the like.

  Specific examples include triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris (β-chloroethyl) phosphate, tris (dichloropropyl). Examples thereof include phosphate and tris (tribromoneopentyl) phosphate.

  In addition to the increase in the size of liquid crystal display devices and the increasing brightness of backlight light sources, higher brightness is required for use in outdoor applications such as digital signage. It is required to be able to withstand use in a high temperature environment, and the film base material preferably has sufficient heat resistance when the tension softening point is 105 ° C to 145 ° C, particularly 110 ° C. It is preferable to control to ˜130 ° C.

  As a specific method for measuring the tension softening point, for example, a Tensilon tester (ORIENTEC Co., RTC-1225A) is used, and the film substrate is cut out at 120 mm (length) × 10 mm (width) with a tension of 10 N. While pulling, the temperature can be raised at a rate of 30 ° C./min. The temperature at the time when the temperature reaches 9 N is measured three times, and the average value can be obtained.

  From the viewpoint of heat resistance, the film substrate preferably has a glass transition temperature (Tg) of 110 ° C. or higher. More preferably, it is 120 ° C. or higher. Especially preferably, it is 150 degreeC or more.

  The glass transition temperature referred to here is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a temperature rising rate of 20 ° C./min. Point glass transition temperature (Tmg).

  When a film base material is used as a protective film for a polarizing plate, unevenness or a change in retardation value occurs due to a dimensional change due to moisture absorption, causing problems such as a decrease in contrast and uneven color. In particular, the above problem becomes significant when the polarizing plate protective film is used in a liquid crystal display device used outdoors. For this reason, the dimensional change rate (%) is preferably less than 0.5%, and more preferably less than 0.3%. The film substrate preferably has a defect of 5 μm or more in diameter in the film plane of 1 piece / 10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, more preferably 0.1 piece / 10 cm square or less. Here, the diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of circumscribed circle) is determined.

  The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape, such as transfer of a roll flaw or an abrasion, the size is confirmed by observing the defect with the reflected light of a differential interference microscope.

  In addition, when observing with reflected light, if the size of the defect is unclear, aluminum or platinum is deposited on the surface for observation. In order to obtain a film having excellent quality expressed by such a defect frequency with high productivity, it is necessary to filter the polymer solution with high precision immediately before casting, to increase the cleanliness around the casting machine, It is effective to set drying conditions after rolling stepwise and to dry efficiently while suppressing foaming.

  When the number of defects is greater than 1/10 cm square, for example, when the film is tensioned during processing in a later process, the film may break with the defects as a starting point, and productivity may decrease. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise.

  Even when visual confirmation is not possible, when a functional layer or the like is formed on the film, the coating agent may not be formed uniformly, resulting in defects (missing coating). Here, the defect is a void in the film (foaming defect) generated due to the rapid evaporation of the solvent in the drying process of the solution casting, a foreign matter in the film forming stock solution, or a foreign matter mixed in the film forming. This refers to the foreign matter (foreign matter defect) in the film.

  Further, the film substrate preferably has a breaking elongation of at least one direction of 10% or more, more preferably 20% or more, in the measurement based on JIS-K7127-1999.

  The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming.

  The thickness of the film substrate is preferably 20 μm or more. More preferably, it is 30 μm or more.

  The upper limit of the thickness is not particularly limited, but in the case of forming a film by a solution casting method, the upper limit is about 250 μm from the viewpoint of applicability, foaming, solvent drying, and the like. The thickness of the film can be appropriately selected depending on the application.

  The film substrate preferably has a total light transmittance of 90% or more, more preferably 93% or more. Moreover, as a realistic upper limit, it is about 99%. In order to achieve excellent transparency expressed by such total light transmittance, it is necessary not to introduce additives and copolymerization components that absorb visible light, or to remove foreign substances in the polymer by high-precision filtration. It is effective to reduce the diffusion and absorption of light inside the film. Also, reduce the surface roughness of the film surface by reducing the surface roughness of the film contact part (cooling roll, calender roll, drum, belt, coating substrate in solution casting, transport roll, etc.) during film formation. It is also effective to reduce the diffusion and reflection of light on the film surface by reducing the refractive index of the acrylic resin.

(Film base film formation)
Next, although the example of the film forming method of a film base material is demonstrated taking a cellulose-ester film and a cellulose-ester resin and acrylic resin film as an example, it is not limited to this.

  As a method for forming a film substrate, a production method such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, a hot press method, or the like can be used.

  From the viewpoint of suppressing the residual of the solvent used for dissolving the cellulose ester resin or acrylic resin, a method of producing by a melt casting film forming method is preferable. Methods formed by melt casting can be classified into melt extrusion molding methods, press molding methods, inflation methods, injection molding methods, blow molding methods, stretch molding methods, and the like. Among these, the melt extrusion method is preferable, in which a film having excellent mechanical strength and surface accuracy is obtained. From the viewpoints of suppressing coloring, suppressing defects of foreign matters, and suppressing optical defects such as die lines, solution casting by casting is preferred. Further, a method of extruding and forming a film forming material on a drum or an endless belt after the film forming material is heated to express its fluidity is also included as a melt casting film forming method.

[Organic solvent]
Organic solvents useful for dissolving cellulose ester resins and acrylic resins, and forming dopes when film substrates are produced by the solution casting method, dissolve acrylic resins, cellulose ester resins, and other additives simultaneously. If it does, it can be used without limitation.

  For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- Examples include 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, and nitroethane. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.

  In addition to the organic solvent, the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels and peeling from the metal support becomes easy, and when the proportion of alcohol is small, the acrylic resin and cellulose ester resin dissolve in a non-chlorine organic solvent system. There is also a role to promote.

  In particular, in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms, at least 15 to 45 mass in total of at least three kinds of acrylic resin, cellulose ester resin, and acrylic particles are used. It is preferable that the dope composition is dissolved in%.

  Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.

[Solution casting method]
The film substrate can be produced by a solution casting method. In the solution casting method, a step of preparing a dope by dissolving a resin and an additive in a solvent, a step of casting the dope on a belt-like or drum-like metal support, and a step of drying the cast dope as a web , A step of peeling from the metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished film.

  The concentration of cellulose ester in the dope, and the concentration of cellulose ester resin / acrylic resin is preferably higher because the drying load after casting on the metal support can be reduced. The load increases, and the filtration accuracy deteriorates. As a density | concentration which makes these compatible, 10-35 mass% is preferable, More preferably, it is 15-25 mass%. The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support.

  The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to −50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferred because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate.

  The preferable support temperature is appropriately determined at 0 to 100 ° C, and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

  When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. .

  In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

  In order for the cellulose ester film to exhibit good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. Especially preferably, it is 20-30 mass% or 70-120 mass%.

  The amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  Further, in the drying step of the cellulose ester film or the cellulose ester resin / acrylic resin film, it is preferable that the web is peeled off from the metal support and further dried to make the residual solvent amount 1% by mass or less, more preferably 0. 0.1 mass% or less, particularly preferably 0 to 0.01 mass% or less.

  In the film drying step, generally, a roll drying method (a method in which webs are alternately passed through a plurality of rolls arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.

[Stretching process]
In the stretching step, the film can be sequentially or simultaneously stretched in the longitudinal direction (MD direction) and the width direction (TD direction) of the film. The draw ratios in the biaxial directions perpendicular to each other are preferably in the range of 1.0 to 2.0 times in the MD direction and 1.07 to 2.0 times in the TD direction, respectively. It is preferable to carry out within a range of 1.0 to 1.5 times and 1.07 to 2.0 times in the TD direction. For example, a method in which peripheral speed differences are applied to a plurality of rolls and a roll peripheral speed difference is used to stretch in the MD direction, both ends of the web are fixed with clips and pins, and the distance between the clips and pins is increased in the traveling direction. And a method of stretching in the MD direction, a method of stretching in the transverse direction and stretching in the TD direction, a method of stretching in the MD / TD direction simultaneously and stretching in both the MD / TD directions, and the like.

  These width maintenance or width direction stretching in the film forming step is preferably performed by a tenter, and may be a pin tenter or a clip tenter.

  The film transport tension in the film forming process such as in the tenter depends on the temperature, but is preferably 120 N / m to 200 N / m, and more preferably 140 N / m to 200 N / m. 140 N / m to 160 N / m is most preferable. When stretching, assuming that the glass transition temperature of the film substrate is Tg, (Tg-30) to (Tg + 100) ° C., more preferably (Tg-20) to (Tg + 80) ° C., and even more preferably (Tg-5) to (T Tg + 20) ° C. The Tg of the film substrate can be controlled by the material type constituting the film and the ratio of the constituting materials. In the application of the present invention, the Tg when the film is dried is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. Especially preferably, it is 150 degreeC or more.

  Accordingly, the glass transition temperature is preferably 190 ° C. or lower, more preferably 170 ° C. or lower. At this time, the Tg of the film can be determined by the method described in JIS K7121.

  The stretching temperature is preferably 150 ° C. or more and the stretching ratio is 1.15 times or more, because the surface is appropriately roughened. Roughening the film surface is preferable because it improves not only the slipperiness but also the surface processability, particularly the adhesion of the antiglare layer.

[Melting method]
The film substrate may be formed by a melt film forming method. The melt film-forming method refers to heating and melting a composition containing an additive such as a resin and a plasticizer to a temperature exhibiting fluidity, and then casting a melt containing a fluid cellulose ester.

  More specifically, the heat melting molding method can be classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like. Among these molding methods, the melt extrusion method is preferable from the viewpoint of mechanical strength and surface accuracy. It is preferable that a plurality of raw materials used for melt extrusion are usually kneaded in advance and pelletized.

  Pelletization may be performed by a known method. For example, dry cellulose ester, plasticizer, and other additives are fed to an extruder with a feeder and kneaded using a single-screw or twin-screw extruder, and formed into a strand from a die. It can be done by extrusion, water cooling or air cooling and cutting.

  The additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.

  A small amount of additives such as particles and antioxidants are preferably mixed in advance in order to mix uniformly.

  The extruder is preferably processed at as low a temperature as possible so as to be able to be pelletized so that the shear force is suppressed and the resin does not deteriorate (decrease in molecular weight, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.

  A film is formed using the pellets obtained as described above. Of course, the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.

  Using a single or twin screw extruder, the pellets are melted at a temperature of about 200 to 300 ° C., filtered through a leaf disk filter, etc. to remove foreign matter, and then formed into a film from a T die. The film is nipped by a cooling roll and an elastic touch roll, and solidified on the cooling roll.

  When introducing from the supply hopper to the extruder, it is preferable to prevent oxidative decomposition or the like under vacuum, reduced pressure, or inert gas atmosphere.

  The extrusion flow rate is preferably performed stably by introducing a gear pump or the like. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances. The stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately intertwined and compressed, and the contact points are sintered and integrated. The density of the fiber is changed depending on the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.

  Additives such as plasticizers and particles may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.

  The film temperature on the touch roll side when the film is nipped between the cooling roll and the elastic touch roll is preferably Tg or more and Tg + 110 ° C. or less of the film. A well-known roll can be used for the roll which has the elastic body surface used for such a purpose.

  The elastic touch roll is also called a pinching rotator. As the elastic touch roll, a touch roll disclosed in registered patent 3194904, registered patent 3422798, Japanese Patent Laid-Open No. 2002-36332, Japanese Patent Laid-Open No. 2002-36333, or the like can be preferably used. These can also use what is marketed.

  When peeling the film from the cooling roll, it is preferable to control the tension to prevent deformation of the film.

  Moreover, it is preferable that the film obtained as described above is stretched by the stretching operation after passing through the step of contacting the cooling roll.

  As a method of stretching, a known roll stretching machine or tenter can be preferably used. The stretching temperature is usually preferably performed in the temperature range of Tg to Tg + 60 ° C. of the resin constituting the film.

  Prior to winding, the ends may be slit and cut to the width of the product, and knurling (embossing) may be applied to both ends to prevent sticking or scratching during winding. The knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing. In addition, since the film has deform | transformed and cannot use as a product normally, the holding | grip part of the clip of both ends of a film is cut out and reused.

(Physical properties of film substrate)
Although the film thickness of the film base material in this embodiment is not specifically limited, 10-200 micrometers is used. In particular, the film thickness is particularly preferably 10 to 100 μm. More preferably, it is 20-60 micrometers.

  The film substrate according to the present invention has a width of 1 to 4 m. In particular, those having a width of 1.4 to 4 m are preferably used, and particularly preferably 1.6 to 3 m. If it exceeds 4 m, conveyance becomes difficult.

  The arithmetic average roughness Ra of the film substrate is preferably 2.0 nm to 4.0 nm, more preferably 2.5 nm to 3.5 nm.

<Other layers>
The optical film according to the present invention can be provided with a backcoat layer and the like.

(Back coat layer)
The optical film according to the present invention is provided with a backcoat layer on the surface of the film base opposite to the side on which the functional layer is provided in order to prevent sticking when the curl or optical film is stored in a roll shape. Also good.

  The back coat layer preferably contains fine particles for the above purpose, and the fine particles include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined silicic acid. Mention may be made of calcium, tin oxide, indium oxide, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Moreover, it is preferable to contain a solvent in order to disperse the fine particles and to dissolve a binder described later to form a coating composition. As the solvent, the solvent described in the functional layer is preferable. The particles contained in the backcoat layer are preferably 0.1 to 50% by mass with respect to the binder. When the back coat layer is provided, the increase in haze is preferably 1.5% or less, and 0.5% or less.

  Further, it is preferable to use a cellulose ester resin such as diacetyl cellulose as the binder.

<Polarizing plate>
A polarizing plate using the optical film according to the present invention will be described. The polarizing plate can be produced by a general method. The back surface side of the optical film according to the present invention is subjected to alkali saponification treatment, and a completely saponified polyvinyl alcohol aqueous solution is used on at least one surface of a polarizing film prepared by immersing and stretching the treated optical film in an iodine solution. It is preferable to bond them together.

  An optical film may be used on the other surface, or another protective film may be used. With respect to the optical film according to the present invention, the protective film used on the other side contains the cellulose triacetate film or thermoplastic acrylic resin and cellulose ester resin which are the above-described film base, and the thermoplastic acrylic resin and It is preferable to use a protective film in which the content ratio of the cellulose ester resin is thermoplastic acrylic resin: cellulose ester resin = 95: 5 to 50:50.

  The retardation Ro in the in-plane direction of the optical film or the protective film is preferably in the range of 0 to 5 nm at 590 nm and the retardation Rt in the thickness direction of -20 to +20 nm. For the protective film, an optical compensation film (retardation film) having a retardation Ro of 590 nm, a retardation of 20 to 70 nm, and an Rt of 70 to 400 nm can be used as a polarizing plate capable of widening the viewing angle. . Furthermore, an optical compensation film having an optically anisotropic layer formed by aligning a liquid crystal compound such as a discotic liquid crystal can also be used. Moreover, as a commercially available protective film used preferably, KC8UX2MW, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC4UEW, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC4FR-1, KC4FR-2, KCUE ( Konica Minolta Opto Co., Ltd.), Zeonore Film (manufactured by Nippon Zeon Co., Ltd.), Arton Film (manufactured by JSR Corporation) and the like.

  The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are ones in which iodine is dyed on a system film and ones in which a dichroic dye is dyed, but it is not limited to this. As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. A polarizing film having a thickness of 5 to 30 μm, preferably 8 to 15 μm, is preferably used.

  On the surface of the polarizing film, one side of the optical film according to the present invention is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

(Adhesive layer)
The pressure-sensitive adhesive layer used on one side of the protective film to be bonded to the substrate of the liquid crystal cell is preferably optically transparent and exhibits moderate viscoelasticity and adhesive properties. Specific examples of the adhesive layer include adhesives or adhesives such as acrylic copolymers, epoxy resins, polyurethane, silicone polymers, polyethers, butyral resins, polyamide resins, polyvinyl alcohol resins, and synthetic rubbers. A film such as a drying method, a chemical curing method, a thermal curing method, a thermal melting method, a photocuring method, or the like can be formed and cured using a polymer such as the above. Among them, the acrylic copolymer can be preferably used because it is most easy to control the physical properties of the adhesive and is excellent in transparency, weather resistance, durability and the like.

<LCD panel>
By incorporating the polarizing plate, a liquid crystal display panel having both high contrast and excellent visibility can be obtained. An example of the configuration of the liquid crystal display panel is shown in FIG.

  The liquid crystal display panel 102 includes a liquid crystal cell 3 and polarizing plates 1 and 2. In the liquid crystal cell 3, the layers of the liquid crystal 21 and the spacer 25 are sandwiched between the alignment film 22 and the color filter 23, and are further fixed by glass plates 24 from both sides.

  Next, the liquid crystal cell 3 will be described.

(Liquid crystal cell)
An arbitrary liquid crystal cell of the display panel is used depending on the driving method. For example, an active matrix type using a thin film transistor, a simple matrix type used in a super twist nematic (STN) liquid crystal display device, and the like can be given.

  The liquid crystal cell preferably includes a pair of substrates and a liquid crystal layer as a display medium sandwiched between the pair of substrates. One substrate (active matrix substrate) includes a switching element (typically a TFT) for controlling the electro-optical characteristics of the liquid crystal, a scanning line for supplying a gate signal to the switching element, and a signal line for supplying a source signal. Provided. The other substrate (color filter substrate) is provided with a color filter. The color filter may be provided on the active matrix substrate. Alternatively, when an RGB three-color light source (which may further include a multicolor light source) is used for the illumination means of the liquid crystal display device as in the field sequential method, the color filter is omitted. The distance between the two substrates is controlled by a spacer. For example, an alignment film made of polyimide is provided on the side of each substrate in contact with the liquid crystal layer.

  In addition to the liquid crystal cell driving methods described above, vertical alignment (VA) mode, twisted nematic (TN) mode, in-plane switching (IPS) mode, vertical alignment electric field control birefringence (ECB) mode, optical Compensated birefringence (OCB) mode etc. are mentioned.

<Image display device>
The image display device of the present invention is particularly preferable in that it is used for a liquid crystal display device in that high performance with excellent contrast and visibility can be obtained.

  The image display device of the present invention is preferable for a reflection type, a transmission type, a transflective type liquid crystal display device, or a liquid crystal display device of various drive systems such as a TN type, STN type, OCB type, VA type, IPS type, ECB type, Used. Further, it can be applied to an organic EL display device, a plasma display, and the like.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1
In order to quantitatively confirm the adhesion between the functional layer of the optical film and the cured resin layer, the adhesion was evaluated in a film state in which the cured resin layer was laminated on the functional layer of the optical film.

<Preparation of film substrate 1>
(Preparation of ester compound 1)
251 g of 1,2-propylene glycol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid, 0.191 g of tetraisopropyl titanate as an esterification catalyst, 2 L four-neck equipped with a thermometer, stirrer, and slow cooling tube The flask is charged and gradually heated with stirring until it reaches 230 ° C. in a nitrogen stream. The ester compound 1 was obtained by making it dehydrate-condense for 15 hours and distilling unreacted 1, 2- propylene glycol under reduced pressure at 200 degreeC after completion | finish of reaction. The acid value was 0.10 mg KOH / g, and the number average molecular weight was 450.

(Preparation of silicon dioxide dispersion)
Aerosil R812 (Nippon Aerosil Co., Ltd., average primary particle diameter of 7 nm)
10 parts by mass Ethanol 90 parts by mass The above was stirred and mixed with a dissolver for 30 minutes, and then dispersed with Manton Gorin.

  88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed for 30 minutes with a dissolver to prepare a silicon dioxide dispersion dilution. It filtered with the fine particle dispersion | distribution dilution liquid filter (Advantech Toyo Co., Ltd .: Polypropylene wind cartridge filter TCW-PPS-1N).

<Production of Film Base 1>
(Dope composition)
Cellulose triacetate A1 (cellulose triacetate synthesized from linter cotton, acetyl group substitution degree 2.88, Mn = 14000) 90 parts by mass Ester compound 1 10 parts by mass Tinuvin 928 (manufactured by BASF Japan Ltd.) 2.5 parts by mass Silicon dispersion diluted solution 4 parts by weight Methylene chloride 432 parts by weight Ethanol 38 parts by weight The above was put into a sealed container, heated and stirred to dissolve completely, and Azumi Filter Paper No. Azumi Filter Paper No. No. 24 was used for filtration to prepare a dope solution.

  Next, the belt casting apparatus was used to uniformly cast on a stainless steel band support. With the stainless steel band support, the solvent was evaporated until the residual solvent amount reached 100%, and the stainless steel band support was peeled off. The cellulose ester film web was evaporated at 35 ° C., slit to 1.65 m width, and stretched in the MD direction (film casting direction) 1.3 times in the TD direction (film width direction) with a tenter. The film was dried at a drying temperature of 160 ° C. while stretching at a magnification of 1.01. The residual solvent amount at the start of drying was 20%. Then, after drying for 15 minutes while transporting the inside of a drying device at 120 ° C. with many rolls, slitting to a width of 1.49 m, applying a knurling process of 15 mm width and 10 μm height to both ends of the film The film substrate 1 was obtained. The residual solvent amount of the film substrate was 0.2%, the film thickness was 80 μm, and the number of turns was 3900 m.

<Preparation of laminated film 1>
The following functional layer composition 1 filtered through a polypropylene filter having a pore size of 0.4 μm is applied onto the film substrate 1 produced above using an extrusion coater, and a constant rate drying zone temperature of 95 ° C. and a reduced rate drying zone temperature. after drying at 95 ° C., the illuminance of the irradiation unit using a UV lamp at 70 mW / cm ^2, thereby curing the coated layer with irradiation dose as 70 mJ / cm ^2, to form a functional layer of the dry film thickness of 5 [mu] m. After forming the functional layer, it was wound up to produce an optical film 1.

  As a result of observing the surface of the optical film 1 with an optical interference type surface roughness meter (New View 5030, manufactured by Zygo), it was found that irregular projection shapes were irregularly arranged as shown in FIG.

Next, the produced optical film 1 is cut into A4 size, and the resin cured layer composition 1 is applied on the functional layer of the cut optical film using an applicator, dried at a drying temperature of 80 ° C., and then oxygenated. While purging with nitrogen so that the concentration becomes an atmosphere of 1.0% by volume or less, using an ultraviolet lamp, the illuminance of the irradiated part is 100 mW / cm ² and the irradiation amount is 500 mJ / cm ^2. After photocuring, it was heated at 80 ° C. for 60 minutes and thermally cured to form a cured resin layer having a dry film thickness of 70 μm, whereby a laminated film 1 was obtained.

[Functional layer composition 1]
The following composition was stirred and mixed with a disper to obtain a functional layer composition 1. Moreover, when only resin was stirred and mixed with a disper and measured using a B-type viscometer under the condition of 25 ° C., the resin viscosity was 400 mPa · s.

Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 85 parts by mass 4-hydroxybutyl acrylate (manufactured by Nippon Kasei Kogyo Co., Ltd.) 15 parts by mass Irgacure 184 (BASF Japan ( 5 mass parts Polyether-modified silicone compound (trade name; KF-355A, manufactured by Shin-Etsu Chemical Co., Ltd., HLB value 12) 5 mass parts Propylene glycol monomethyl ether 10 mass parts Methyl acetate 55 mass parts Methyl ethyl ketone 55 mass parts Part [Resin cured layer composition 1]
The following composition was mixed with a disper to obtain a cured resin layer composition 1.

Polyurethane acrylate (trade name: UV-3000B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
50 parts by mass Isobornyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 30 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 3 parts by mass Photopolymerization initiator (trade name; SpeedCure TPO, manufactured by Nippon Siebel Hegner Co., Ltd.) ) 1 part by mass Thermal polymerization initiator (organic peroxide) (trade name; Perbutyl O, manufactured by NOF Corporation) 3 parts by mass <Preparation of laminated films 2 to 8>
In the production of the optical film 1, laminated films 2 to 8 were produced in the same manner except that the temperature in the decreasing rate drying section was changed to the conditions described in Table 1.

<Preparation of laminated film 9>
In the production of the laminated film 4, a laminated film 9 was produced in the same manner except that the cured resin layer composition 1 was changed to the cured resin layer composition 2.

[Resin cured layer composition 2]
The following composition was mixed with a disper to obtain a cured resin layer composition 2.

70 mass parts dicyclopentenyloxyethyl methacrylate 30 mass parts 2-hydroxybutyl methacrylate 10 mass parts terpene-based hydrogenated resin 30 mass parts butadiene heavy styrene ester product of maleic anhydride adduct of polyisoprene polymer and 2-hydroxyethyl methacrylate Combined 140 parts by weight Irgacure 184 (manufactured by BASF Japan) 4 parts by weight Photopolymerization initiator (trade name; SpeedCure TPO, manufactured by Nippon Shibel Hegner) 0.5 parts by weight Thermal polymerization initiator (organic peroxide) (Product name: Perbutyl O, manufactured by NOF Corporation) 10 parts by mass <Preparation of laminated film 10>
In the production of the laminated film 4, a laminated film 10 was produced in the same manner except that the cured resin layer composition 1 was changed to the cured resin layer composition 3.

[Resin cured layer composition 3]
The following composition was mixed with a disper to obtain a cured resin layer composition 3.

100 mass parts dicyclopentenyloxyethyl methacrylate 30 mass parts 2-hydroxybutyl methacrylate 10 mass parts Terpene-based hydrogenated resin 30 mass parts Butadiene weight 100 mass parts Dicyclopentenyloxyethyl methacrylate 30 mass parts Polyisoprene polymer maleic anhydride adduct and 2-hydroxyethyl methacrylate Combined 210 parts by weight Irgacure 184 (manufactured by BASF Japan) 7 parts by weight Photopolymerization initiator (trade name; SpeedCure TPO, manufactured by Nippon Shibel Hegner) 1.5 parts by weight Thermal polymerization initiator (organic peroxide) (Product name: Perbutyl O, manufactured by NOF Corporation) 13 parts by mass <Preparation of laminated film 11>
In the production of the laminated film 4, a laminated film 11 was produced in the same manner except that the cured resin layer composition 1 was changed to the cured resin layer composition 4.

[Resin cured layer composition 4]
The following composition was mixed with a disper to obtain a cured resin layer composition 4.

70 mass parts dicyclopentenyloxyethyl methacrylate (trade name; FA512M, Hitachi) esterified product of maleic anhydride adduct of polyisoprene polymer and 2-hydroxyethyl methacrylate (trade name; UC-203, manufactured by Kuraray Co., Ltd.) Kasei Kogyo Co., Ltd.) 30 parts by mass 2-hydroxybutyl methacrylate (trade name Light Ester HOB, manufactured by Kyoeisha Chemical Co., Ltd.) 10 parts by mass Terpene-based hydrogenated resin (trade name; Clearon P-85, Yasuhara Chemical Co., Ltd.) Made)
30 parts by mass butadiene polymer (trade name; Polyoil 110, manufactured by Nippon Zeon Co., Ltd.)
35 parts by mass Irgacure 184 (manufactured by BASF Japan) 5 parts by mass Photopolymerization initiator (trade name; SpeedCure TPO, manufactured by Nippon Siebel Hegner) 2 parts by mass Thermal polymerization initiator (organic peroxide) (trade name) ; Perbutyl O, manufactured by NOF Corporation) 6 parts by mass <Preparation of laminated film 12>
In the production of the laminated film 4, a laminated film 12 was produced in the same manner except that the cured resin layer composition 1 was changed to the cured resin layer composition 5.

[Resin cured layer composition 5]
The following composition was mixed with a disper to obtain a cured resin layer composition 5.

Polybutadiene acrylate (trade name; TE-2000, manufactured by Nippon Soda Co., Ltd.)
50 parts by mass Hydroxylethyl methacrylate (trade name; Light Ester HO, manufactured by Kyoeisha Chemical Co., Ltd.) 20 parts by mass Irgacure 184 (manufactured by BASF Japan) 3 parts by weight Photopolymerization initiator (trade name; SpeedCure TPO, Nippon Siber Hegner) 1 part by mass Thermal polymerization initiator (organic peroxide) (trade name; Perbutyl O, manufactured by NOF Corporation) 2 parts by mass <Preparation of laminated film 13>
In the production of the laminated film 4, a laminated film 13 was produced in the same manner except that the cured resin layer composition 1 was changed to the cured resin layer composition 6.

[Resin cured layer composition 6]
The following composition was mixed with a disper to obtain a cured resin layer composition 6.

Polyurethane acrylate (trade name: UV-3000B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 50 parts by mass Tricyclodecane dimethanol acrylate (trade name: NK ester LC2, manufactured by Shin-Nakamura Chemical Co., Ltd.) 30 parts by mass Irgacure 184 (Made by BASF Japan Co., Ltd.) 3 parts by mass photopolymerization initiator (trade name; SpeedCure TPO, manufactured by Nippon Siebel Hegner Co., Ltd.) 1 part by mass thermal polymerization initiator (organic peroxide) (trade name: perbutyl O, Japan 3 parts by mass <Preparation of laminated film 14>
In the production of the laminated film 4, a laminated film 14 was produced in the same manner except that the cured resin layer composition 1 was changed to the cured resin layer composition 7.

[Resin cured layer composition 7]
The following composition was mixed with a disper to obtain a cured resin layer composition 7.

Polybutadiene acrylate (trade name; TE-2000, manufactured by Nippon Soda Co., Ltd.)
50 parts by mass of isobornyl acrylate (trade name: IBXA, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
20 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 3 parts by mass photopolymerization initiator (trade name; SpeedCure TPO, manufactured by Nippon Siebel Hegner) 1 part by mass thermal polymerization initiator (organic peroxide) (trade name) ; Perbutyl O, manufactured by NOF Corporation) 4 parts by mass <Preparation of laminated film 15>
In the production of the optical film 1, the laminated film 15 was produced in the same manner except that the functional layer composition 1 was changed to the following functional layer composition 2 and the temperature of the decreasing rate drying section in the drying step was changed to 110 ° C. did.

[Functional layer composition 2]
The following composition was stirred and mixed with a disper to obtain a functional layer composition 2. Moreover, when only resin was stirred and mixed with a disper and measured using a B-type viscometer under the condition of 25 ° C., the resin viscosity was 700 mPa · s.

Ditrimethylolpropane tetraacrylate (NK ester AD-TMP, manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts by mass Ethoxylated pentaerythritol tetraacrylate (NK ester ATM-35E, manufactured by Shin-Nakamura Chemical Co., Ltd.) 30 parts by mass Penta Erythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 20 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 5 parts by mass Polyether-modified silicone compound (trade name; KF- 6004, manufactured by Shin-Etsu Chemical Co., Ltd., HLB value 5) 5 parts by mass Propylene glycol monomethyl ether 10 parts by mass Methyl acetate 55 parts by mass Methyl ethyl ketone 55 parts by mass <Production of laminated films 16 to 18>
In the production of the optical film 15 in the laminated film 15, laminated films 16 to 18 were produced in the same manner except that the temperature in the decreasing rate drying section was changed to the conditions described in Table 1.

<Preparation of laminated film 19>
In the production of the laminated film 16, a laminated film 19 was produced in the same manner except that the resin cured layer composition 1 was changed to the resin cured layer composition 5.

<Preparation of laminated film 20>
In the production of the optical film 15, the functional layer composition 2 was changed to the functional layer composition 3 prepared with reference to Example 1 of JP-A-2008-225195, and the drying temperature was further changed to JP-A-2008-225195. A laminated film 20 was produced in the same manner except that the temperature was set to 70 ° C., which was the same as Example 1 of the publication.

[Functional layer composition 3]
The following composition was mixed with a disper to obtain a functional layer composition 3.

Cyclomer P (ACA) 320 (unsaturated group-containing acrylic resin mixture, manufactured by Daicel Chemical Industries, Ltd.) 5.65 parts by mass Polymethyl methacrylate (weight average molecular weight 480000; manufactured by Mitsubishi Rayon Co., Ltd., BR88) 9 parts by mass Dipentaerythritol hexaacrylate (DPHA, manufactured by Daicel Cytec Co., Ltd.) 6.3 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 0.5 parts by mass Methyl ethyl ketone (MEK) 0.1 parts by mass 1- Butanol 5.4 parts by mass 1-methoxy-2-propanol 1.89 parts by mass <Preparation of laminated film 21>
In the production of the laminated film 15, the functional layer composition 2 was changed to the functional layer composition 4 prepared with reference to Example 3 of JP-A-2007-58204, and the drying temperature was further changed to JP-A-2007-58204. A laminated film 21 was produced in the same manner as the laminated film 15 except that the temperature was changed to 80 ° C., which was the same as Example 3 of the publication.

[Functional layer composition 4]
The following composition was stirred and mixed with a disper to obtain a functional layer composition 4. Further, only the resin was stirred and mixed with a disper, and measured using a B-type viscometer under the condition of 25 ° C., the resin viscosity was 6500 mPa · s.

Dipentaerythritol hexaacrylate (DPHA, manufactured by Daicel Cytec Co., Ltd.) 92 parts by mass Methacrylate copolymer (Safmer ST3600, manufactured by Mitsubishi Chemical Corporation)
15 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 4 parts by mass Ethanol 45 parts by mass Toluene 15 parts by mass <Preparation of laminated film 22>
In the production of the optical film 15, the functional layer composition 2 was changed to the functional layer coating composition 5 prepared with reference to the antiglare layer coating liquid B of Example 1 of JP-A-2007-45142, Further, a laminated film 22 was produced in the same manner except that the drying temperature in the constant rate drying section and the decreasing rate drying section was changed to 90 ° C. as in Example 1 of JP-A-2007-45142.

[Functional layer composition 5]
After mixing 6.3 parts by mass of crosslinked poly (acryl-styrene) particles in a solvent having the following blending ratio, the mixture was stirred with an air disper for 30 minutes to obtain a particle dispersion. To this particle dispersion, other materials were stirred and mixed with a disper to prepare a functional layer composition 5. Further, only the resin was stirred and mixed with a disper, and measured using a B-type viscometer under the condition of 25 ° C., the resin viscosity was 6000 mPa · s.

Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) 25.4 parts by mass Cross-linked poly (acryl-styrene) particles having an average particle size of 3.5 μm (copolymerization composition ratio = 50 / 50, refractive index 1.536) 6.3 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 1.3 parts by mass Fluorine-based surface modifier (FP-149) 0.04 parts by mass Silane coupling agent (product) Name: KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.)
5.2 parts by mass Cellulose acetate butyrate (CAB-531-1, manufactured by Eastman Chemical Co., Ltd.) 0.5 parts by mass Methyl isobutyl ketone 54.7 parts by mass Propylene glycol 6.3 parts by mass <Preparation of laminated film 23 >
An uneven roll was produced with reference to Example 1 of JP-A-2006-53371. Next, referring to Example 1 of Japanese Patent Application Laid-Open No. 2006-53371, the functional layer composition 1 is applied on the film substrate 1 and then dried at 60 ° C., and the surface of the functional layer is uneven. Was pressed to bring the functional layer and the roll into close contact. While the adhesion was, the illuminance of the irradiation unit using a UV lamp at 70 mW / cm ^2, thereby curing the coated layer with irradiation dose as 70 mJ / cm ^2, to form a functional layer of the dry film thickness of 5 [mu] m. After forming the functional layer, it was wound up to produce an optical film 2. Next, the produced optical film 2 is cut into A4 size, and the resin cured layer composition 1 is applied on the functional layer of the cut optical film using an applicator, dried at a drying temperature of 80 ° C., and then oxygenated. While purging with nitrogen so that the concentration becomes an atmosphere of 1.0% by volume or less, using an ultraviolet lamp, the illuminance of the irradiated part is 100 mW / cm ² and the irradiation amount is 500 mJ / cm ^2. After photocuring, the film was heated at 80 ° C. for 60 minutes and thermally cured to form a cured resin layer having a dry film thickness of 70 μm to obtain a laminated film 23.

<Evaluation of film>
The following items were evaluated for the obtained optical films 1 to 23 and laminated films 1 to 23.

  The results are shown in Table 1.

1. Optical film a. Haze measurement The internal haze (Hi) and surface haze (Hs) of the optical films 1 to 23 prepared above were measured by the following measurement. The obtained results are shown in Table 1.

・ Internal haze (Hi)
A few drops of silicone oil were dropped on the front and back surfaces of the optical film. Next, the optical film in which silicone oil was dropped was sandwiched between two glass plates (micro slide glass product number S9111, manufactured by MATSUNAMI) with a thickness of 1 mm, and the two optical plates and the obtained optical film were optically combined. It was made to adhere to. The haze (Ha) of the sample which was optically adhered and the surface haze was removed was measured using a measuring machine (NDH2000) manufactured by Nippon Denshoku Industries Co., Ltd. Next, only silicone oil was interposed between two glass plates. The glass haze (Hb) was measured by inserting Hb, and Hb was subtracted from Ha to calculate the internal haze (Hi) of the optical film.

・ Surface haze (Hs)
The total haze of the optical film was measured using NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.), and the surface haze (Hs) was calculated by subtracting the internal haze (Hi) from the total haze.

b. Arithmetic average roughness Ra measurement The arithmetic average roughness Ra of the functional layers of the optical films 1 to 23 prepared above was measured 10 times using an optical interference type surface roughness meter (New View 5030, manufactured by Zygo). The arithmetic average roughness Ra of each optical film was determined from the average of the measurement results.

2. Laminated film a. Storage elastic modulus Under the same conditions as each of the laminated films 1 to 23 produced above, resin curing was performed with a viscoelasticity measuring device (DMS6100 manufactured by Seiko Instruments Inc.) using a sample obtained by curing a cured resin layer on glass. The storage elastic modulus (Pa) of the layer (measurement frequency: 1 Hz, 25 ° C.) was measured, and this measurement result was taken as the storage elastic modulus of the cured resin layer of the laminated film.

3. Post-durability adhesion evaluation a. Durability test After the laminated films 1 to 23 were stored at 90 ° C. and 95% for 200 hours, they were put into a cycle thermo (−40 ° C. for 30 minutes and then left at 85 ° C. for 30 minutes alternately for 500 cycles) The sample was irradiated with light for 120 hours using a weather resistance tester (eye super UV tester, Iwasaki Electric Co., Ltd.)

  On the surface of the cured resin layer of the laminated film subjected to the above durability test, 11 razor blades are cut at an angle of 90 ° with respect to the surface and 11 cuts are made at 1 mm intervals vertically and horizontally to produce 100 1 mm square grids. did. A commercially available cellophane tape is affixed on this, holding one end by hand and pulling it forcefully vertically, and visually observing the ratio of the area where the thin film was peeled off to the tape area affixed from the score line, Evaluation was made according to the following criteria.

A: Not peeled at all ○: The peeled area ratio was less than 10% Δ: The peeled area ratio was 10% or more and less than 20% ×: The peeled area ratio was 20% or more Met

As can be seen from the results in Table 1, the functional film has an arithmetic average roughness Ra of 25 to 300 nm and an internal haze of 0 to 1.0%, and a storage elastic modulus at 25 ° C. It can be seen that the laminated film obtained by laminating the cured optical resin layer having a thickness of 1 × 10 ⁷ Pa or less is excellent in adhesion between the functional layer and the cured optical resin layer after the weather resistance test. Moreover, even when the surface haze / internal haze ratio of the functional layer of the optical film according to the present invention is 3.5 or more, the adhesion after the weather resistance test is excellent. In addition, the functional layer of the optical film according to the present invention is substantially free of fine particles and non-reactive polymer, and thus the above characteristics are obtained. It is preferable that substantially no fine particles and non-reactive polymer are contained.

Example 2
<Preparation of Polarizing Plate 101>
(Alkaline saponification treatment)
The produced optical film 1 is attached to one surface of the polarizing film, and a protective film made of KC4FR-1 (manufactured by Konica Minolta Opto Co., Ltd.), which is an optical compensation film, is attached to the other surface of the polarizing film. A plate 101 was produced. (See Figure 3 for configuration.)
(A) Production of Polarizing Film What was impregnated with 10 parts by mass of glycerin and 170 parts by mass of water in 100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400. After melt-kneading and defoaming, it was melt-extruded from a T-die onto a metal roll to form a film. Then, it dried and heat-processed and obtained the PVA film. The obtained PVA film had an average thickness of 25 μm, a moisture content of 4.4%, and a film width of 3 m.

  Next, the obtained PVA film was continuously processed in the order of preliminary swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the PVA film was preliminarily swollen in water at a temperature of 30 ° C. for 30 seconds, and immersed in an aqueous solution having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter at a temperature of 35 ° C. for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in a 50% aqueous solution with a boric acid concentration of 4% under the condition that the tension applied to the film was 700 N / m, and the potassium iodide concentration was 40 g / liter and the boric acid concentration was 40 g / liter. Then, it was immersed in an aqueous solution having a zinc chloride concentration of 10 g / liter and a temperature of 30 ° C. for 5 minutes for fixing. Thereafter, the PVA film was taken out, dried with hot air at a temperature of 40 ° C., and further heat-treated at a temperature of 100 ° C. for 5 minutes. The obtained polarizing film had an average thickness of 13 μm, a polarizing performance of a transmittance of 43.0%, a polarization degree of 99.5%, and a dichroic ratio of 40.1.

(B) Production of Polarizing Plate A polarizing plate 101 was produced by bonding the polarizing film, the protective film (KC4FR-1) and the optical film 1 according to the following steps 1 to 4.

  Process 1: The above-mentioned polarizing film 3 was immersed for 1 to 2 seconds in the storage tank of the polyvinyl alcohol adhesive agent solution of 2 mass% of solid content.

  Step 2: The alkali film was subjected to an alkali saponification treatment under the following conditions on the optical film 1 and a protective film having a peelable protective film (PET) attached to the functional layer. Next, excess adhesive adhered to the polarizing film 3 immersed in the polyvinyl alcohol adhesive solution in Step 1 was gently removed, and the polarizing film was sandwiched between the optical film 1 and the protective film as shown in FIG. .

(Alkaline saponification treatment)
Saponification step 2.5M-KOH 50 ° C. 120 seconds Water washing step Water 30 ° C. 60 seconds Neutralization step 10 parts by mass HCl 30 ° C. 45 seconds Water washing step Water 30 ° C. 60 seconds After saponification treatment, water washing, neutralization, water washing in this order And then dried at 100 ° C.

Step 3: The laminate was bonded at a speed of about 2 m / min at a pressure of ^{20 to} 30 N / cm ² with two rotating rollers. At this time, it was carried out with care to prevent bubbles from entering.

  Step 4: The sample prepared in Step 3 was dried in a dryer at a temperature of 100 ° C. for 5 minutes to prepare a polarizing plate.

  Step 5: A commercially available acrylic pressure-sensitive adhesive is applied to the protective film side of the polarizing plate prepared in Step 4 so that the thickness after drying is 25 μm, and dried in an oven at 110 ° C. for 5 minutes to form an adhesive layer. A peelable protective film was attached to the adhesive layer. This polarized light was cut (punched) to produce a polarizing plate 101.

<Preparation of polarizing plate 201 with protective part>
Using the produced polarizing plate 101, as shown in (I) to (II) of FIG.

  First, the function of the optical film of the protective part 103 and the polarizing plate 101 (polarizing plate 1 in FIG. 2) to which the resin cured layer composition 1 prepared in Example 1 (resin curing layer composition 110 in FIG. 2) was dropped. The sex layer was overlaid. A light shielding part 50 having a width of 5 mm is formed on the outer periphery of the protection part 103.

Next, in the same manner as the formation of the cured resin layer in Example 1, first, photocuring was performed by ultraviolet irradiation as shown in FIG. The ultraviolet irradiation was performed using an ultraviolet lamp at an irradiation part with an illuminance of 100 mW / cm ² and an irradiation amount of 500 mJ / cm ² .

  After photocuring, it was placed on a heating stage, heated at 80 ° C. for 60 minutes, and thermally cured to bond the protective part and the polarizing plate to produce a polarizing plate 201 with a protective part.

<Production of Liquid Crystal Display Device 401>
The polarizing plate on the viewing side of the liquid crystal panel of Sony liquid crystal television (KDL-40HX700) was peeled off. Next, the peelable protective film of the pressure-sensitive adhesive layer (not shown) of the produced polarizing plate 201 with a protective part (see FIG. 2 (II) is peeled off), and the pressure-sensitive adhesive layer and the liquid crystal cell glass are bonded together. Then, a liquid crystal panel 301 (the liquid crystal panel 102 in FIG. 2) was manufactured, and a liquid crystal display device 401 was obtained.

<Preparation of polarizing plates 102 to 123>
Polarizers 102 to 123 were produced in the same manner except that the optical film 1 was changed to the optical films 2 to 23 in the production of the polarizing plate 101.

<Preparation of polarizing plates 202 to 223 with a protective part>
In preparation of the polarizing plate 201 with a protection part, the polarizing plates 202-223 with a protection part were similarly produced except having changed the resin cured layer composition 1 as shown in Table 2, respectively.

<Production of Liquid Crystal Display Devices 402 to 423>
Liquid crystal panels 302 to 323 and liquid crystal display devices 402 to 423 were produced in the same manner except that the polarizing plate 201 with a protective part was changed to the polarizing plates 202 to 223 with a protective part in the production of the liquid crystal display device 401.

<Evaluation>
The following evaluation was performed about the produced polarizing plates 201-223 with a protection part and the liquid crystal display devices 401-423.

1. Polarizing plates 201 to 223 with a protective part
a. Storage elastic modulus The storage elastic modulus of the cured resin layer was determined in the same manner as the method calculated for the laminated film of Example 1. The obtained results are shown in Table 2.

b. Durability test After protecting polarizing plates 201 to 223 with a protective part at 90 ° C. and 95% for 200 hours, cycle thermostat (−40 ° C. for 30 minutes and then 85 ° C. for 30 minutes alternately for 500 cycles) After the charging, the sample was irradiated with light for 200 hours with a weather resistance tester (eye super UV tester, manufactured by Iwasaki Electric Co., Ltd.).

c. Adhesion evaluation after endurance Next, regarding the polarizing plates 201 to 223 with a protective part after the endurance test, the adhesion state between the functional layer and the cured resin layer is as follows from the side of the polarizing plate in the presence of a daylight straight tube fluorescent lamp. The visual evaluation was performed based on the criteria.

  The obtained results are shown in Table 2.

○: No peeling at all ×: Partial peeling was observed.

2. Liquid crystal display devices 401 to 423
a. Front contrast evaluation In an environment of 23 ° C. and 55% RH, the backlight of each liquid crystal display device was lit continuously for one week, and measurement was performed. For measurement, EZ-Contrast 160D manufactured by ELDIM was used to measure the luminance from the normal direction of the display screen of white display and black display with a liquid crystal display device, and the ratio was defined as the front contrast. The higher the value, the better the contrast.

  Front contrast = (brightness of white display measured from the normal direction of the display device) / (brightness of black display measured from the normal direction of the display device) Table 2 shows the obtained results.

b. Visibility evaluation The liquid crystal display devices 401 to 423 were allowed to stand at 80 ° C. and 85% RH for 200 hours, then returned to 23 ° C. and 55% RH, and the visibility was evaluated according to the following criteria. The obtained results are shown in Table 2.

A: No wavy unevenness is observed on the surface. O: A slight wavy unevenness is observed on the surface. X: A fine wavy unevenness is observed on the surface.

c. Comprehensive evaluation The balance between front contrast and visibility was evaluated as a comprehensive evaluation based on the following criteria and shown in Table 2.

A: The front contrast is 1100 or more and the visibility evaluation is A
○: The front contrast is 1100 or more and the visibility evaluation is ○
X: Front contrast is 1100 or less or visibility evaluation is x

  As can be seen from the results in Table 2, also in the liquid crystal display device, the configuration of the present invention is excellent in adhesion after a durability test between the cured resin layer provided in the protective portion and the functional layer of the polarizing plate. I understand. In addition, it can be seen that the liquid crystal display device of the present invention has excellent contrast and visibility, and is excellent as an image display device. As a result, the liquid crystal display device of the present invention was very excellent with no eye fatigue even when viewed for a long time.

1 Polarizing plate 1
2 Polarizing plate 2
DESCRIPTION OF SYMBOLS 3 Liquid crystal cell 10 Optical film 11 Base film 12 Functional layer 13 Polarizing film 14 Protective film 15 Adhesive layer 16 Protrusion part 20 Base part 21 Liquid crystal 22 Orientation film 23 Color filter 24 Glass plate 25 Spacer 30 Translucent member 32 Ultraviolet light irradiation Device 33 Ultraviolet ray 50 Light shielding portion 60 Frame 70 Backlight 90 Spacer 101 Liquid crystal display device 102 Liquid crystal display panel 103 Protection portion 105 Void 110 Curable resin composition 140 Resin cured layer

Claims (5)

In an image display device having a cured resin layer between a protective part and a polarizing plate in which an optical film having a functional layer on a film substrate and a polarizing film are laminated in this order, the functional layer protrudes The protrusions are irregularly arranged on the film substrate irregularly, the arithmetic average roughness Ra of the functional layer is 25 to 300 nm, and the haze caused by internal scattering is 0. An image display device characterized in that the storage elastic modulus at 25 ° C. of the cured resin layer is 1 × 10 ⁷ Pa or less. The image display device according to claim 1, wherein the functional layer has an arithmetic average roughness Ra of 65 to 130 nm. The image display device according to claim 1, wherein the functional layer has a surface haze and a haze ratio resulting from surface haze / internal scattering is 3.5 or more. The image display device according to claim 1, wherein the functional layer substantially does not contain fine particles or a non-reactive polymer. The image display device according to claim 1, wherein the image display device is a liquid crystal display device.