JP2022164005A - optical laminate - Google Patents

Abstract

To provide an optical laminate which is thin but can be easily transferred onto any transferred material by suppressing the occurrence of sticking deviation and wrinkles during transfer to the transferred material.SOLUTION: Disclosed is an optical laminate which includes: a first base film: a first stress relaxation layer; a polarization layer; a pressure-sensitive adhesive layer; a retardation layer; a second stress relaxation layer; and a second base film in this order. The total thickness of layers located between the first stress relaxation layer and the second stress relaxation layer is 20 μm or less. The elastic modulus of the first base film at 23°C is 2,500 to 6,000 MPa. The first stress relaxation layer is peelable from the layer adjacent to the surface opposite to the first base film of the first stress relaxation layer, and the second base film is a peelable substrate film.SELECTED DRAWING: None

Description

The present invention relates to transferable optical laminates.

A circularly polarizing plate including a polarizing film and a retardation film is widely used in a flat panel display (FPD) such as an organic EL display. As such a circularly polarizing plate, an optical laminate in which the polarizing film and/or the retardation film is an optically anisotropic layer comprising a coating layer obtained by coating a polymerizable liquid crystal compound on a substrate and polymerizing it. are known (Patent Documents 1 to 5).

JP 2014-63143 A JP 2017-83843 A JP 2020-56834 A JP 2019-91088 A JP 2020-13164 A

The optical layered body as disclosed in the above patent document is produced by transferring an optically anisotropic layer formed on a base material to a transfer material, that is, by peeling off the base material and removing an adhesive layer or the like. It can be incorporated into a display device or the like by laminating it to a transfer material through an intermediate layer.
However, when the thickness of the optical layered body is reduced, it tends to be difficult to handle, and when the substrate is peeled off and the optically anisotropic layer is transferred to the transferred body, problems such as lamination misalignment and wrinkles occur. may appear.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical layered body that is thin yet suppresses the occurrence of lamination misalignment and wrinkles when transferred to a transfer-receiving body, and that can be easily transferred to any transfer-receiving body. .

The inventors of the present invention have completed the present invention as a result of intensive studies to solve the above problems. That is, the present invention includes the following aspects.
[1] An optical laminate comprising a first substrate film, a first stress relaxation layer, a polarizing layer, an adhesive layer, a retardation layer, a second stress relaxation layer, and a second substrate film in this order,
The total thickness of the layers located between the first stress relaxation layer and the second stress relaxation layer is 20 μm or less,
The elastic modulus of the first base film at 23° C. is 2,500 to 6,000 MPa,
A substrate film in which the first stress relaxation layer can be peeled off from the layer adjacent to the surface of the first stress relaxation layer opposite to the first base film, and the second substrate film can be peeled off. is an optical laminate.
[2] The optical layered body according to [1], further comprising a diffusion prevention layer between the first stress relieving layer and the polarizing layer.
[3] The optical laminate according to [1] or [2], wherein the polarizing layer is a cured liquid crystal layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting a smectic liquid crystal phase and a dichroic dye.
[4] The retardation layer according to any one of [1] to [3], which is a horizontally aligned liquid crystal cured layer in which the polymerizable liquid crystal compound is cured in a state of being horizontally aligned with respect to the plane of the substrate. Optical laminate.
[5] The optical laminate according to any one of [1] to [4], wherein the first base film has a thickness of 30 to 120 μm.
[6] The film thickness (T1) of the laminate (laminate a) consisting of the layers from the first base film to the first stress relaxation layer, and the diffusion prevention positioned between the first stress relaxation layer and the polarizing layer The thickness (T2) of the laminate (laminate b) consisting of the layers from the layer to the second stress relaxation layer is represented by the formula (1):
T1/T2≧1.5 (1)
The optical laminate according to any one of [2] to [5], which satisfies
[7] Peeling force (F1) when peeling the laminate (laminate a) consisting of the layers from the first substrate film to the first stress relaxation layer from the optical laminate, and the second substrate from the optical laminate The peel force (F2) when peeling the film is expressed by the formula (2):
0.02 (N/25mm)≦|F1−F2| (2)
The optical laminate according to any one of [1] to [6], which satisfies
[8] The optical laminate according to any one of [2] to [7], wherein the anti-diffusion layer has a thickness of 5 μm or less.
[9] further comprising a vertically aligned liquid crystal cured layer between the polarizing layer and the second stress relaxation layer, in which the polymerizable liquid crystal compound is cured in a state in which it is aligned vertically with respect to the plane of the substrate; The optical laminate according to any one of [8].

According to the present invention, it is possible to provide an optical layered body that is thin yet suppresses the occurrence of lamination misalignment and wrinkles when transferred to a transfer-receiving body, and that can be easily transferred to any transfer-receiving body. .

1 is a schematic cross-sectional view showing an example of the layer structure of an optical layered body of the present invention; FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of an optical layered body of the present invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. It should be noted that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the gist of the present invention.

The optical laminate of the present invention comprises a first substrate film, a first stress relaxation layer, a polarizing layer, an adhesive layer, a retardation layer, a second stress relaxation layer, and a second substrate film in this order. An example of the layer structure of the optical layered body of the present invention will be described below with reference to FIGS. 1 and 2, but the layered body of the present invention is not limited to these embodiments.

The optical layered body 11 shown in FIG. The material film 7 is laminated in this order. In the optical laminate 11 shown in FIG. 1, between the first stress relaxation layer 2 and the layer adjacent to the surface of the first stress relaxation layer 2 opposite to the first base film 1 (in FIG. 1, (between the first stress relieving layer 2 and the polarizing layer 3), and the second base film 7 can be peeled off. The peelable second substrate film 7 is peeled off from the optical laminate 11, and the first substrate film 1, the first stress relaxation layer 2, the polarizing layer 3, the adhesive layer 4, the retardation layer 5, the second A laminate structure 12 consisting of two stress relieving layers 6 can be transferred to a transferee (substrate), for example an OLED substrate. After that, the first stress relaxation layer 2 is peeled off with the first base film laminated, and a laminate structure consisting of the polarizing layer 3, the adhesive layer 4, the retardation layer 5 and the second stress relaxation layer 6 is obtained. A display device containing 13 is obtained. On the surface of the polarizing layer 3 exposed by peeling the first stress relieving layer 2, for example, a front plate with an adhesive can be attached. The order in which the first stress relieving layer and the second base film are peeled off from the optical laminate of the present invention is not necessarily limited. In order to obtain the effects of the present invention more remarkably, in one embodiment of the present invention, after the second base film is peeled first and laminated to the substrate, the first stress relaxation layer is attached together with the first base film. exfoliate.

In one preferred embodiment of the present invention, the optical layered body of the present invention further includes an anti-diffusion layer between the first stress relieving layer and the polarizing layer. The optical laminate 11 shown in FIG. 2 has an anti-diffusion layer 8 between the first stress relieving layer 2 and the polarizing layer 3 . In order to improve the effect of suppressing the diffusion of the dichroic dye from the polarizer, the polarizing layer 3 may also have a diffusion prevention layer 9 on the side opposite to the first stress relaxation layer 2 .

The optical laminate of the present invention comprises a first substrate film, a first stress relaxation layer, a polarizing layer, an adhesive layer, a retardation layer, a second stress relaxation layer, a second substrate film and a diffusion prevention layer. , as long as it does not affect the effects of the present invention, it may further include other layers. Other layers include, for example, an alignment film for forming the polarizing layer, an alignment film for forming the retardation layer, a second retardation layer, an adhesive layer other than the polarizing layer and the adhesive layer between the retardation layers. Examples include an adhesive layer and a resin layer having UV absorbability.

Hereinafter, each configuration of the optical layered body of the present invention will be described in detail.

[First base film and second base film]

In the optical laminate of the present invention, the first base film is peelable from the layer adjacent to the surface of the first stress relaxation layer opposite to the first base film of the optical laminate together with the first stress relaxation layer. As such, it is a layer laminated to the optical laminate. It is preferable that the layers from the first base film to the first stress relaxation layer are laminated with a certain degree of adhesion so that they can be peeled together when peeled. In general, it is not necessary to provide a substrate film on the side opposite to the side to be transferred to the substrate (usually the second substrate side in the optical laminate of the present invention). In the present invention, when the second base film is peeled off and transferred to the substrate, the first base film present as the outermost layer on the side opposite to the transfer side and the first base film laminated on the first base film 1 The stress relaxation layer plays a role of reinforcing the laminate structure as a whole, so that although it is thin, air bubbles and wrinkles are generated when the second base film is peeled off and transferred to the substrate, and adhesion to the substrate is prevented. A high effect of suppressing misalignment is obtained. On the other hand, the second base film is a layer releasably laminated on the optical layered body.

In one embodiment of the present invention, the elastic modulus at 23° C. of the first base film is 2,500-6,000 MPa. When the elastic modulus in the first base film is equal to or higher than the above lower limit, the strength tends to be high, and it can be said that the film has a high so-called "elasticity". By arranging such a base film as the outermost layer on the side opposite to the second base film, air bubbles and wrinkles tend to be less likely to occur when the second base film is peeled off and transferred to the substrate. In addition, when the elastic modulus is equal to or less than the above upper limit, the strength and rigidity against stress are well-balanced, and by having moderate flexibility, the second base film is peeled and bonded to the substrate when transferred to the substrate. It tends to be excellent in the effect of suppressing displacement. In the present invention, the elastic modulus of the first base film at 23° C. is more preferably 3,000 MPa or more, still more preferably 3,500 MPa or more, and more preferably 5,500 MPa or less.

In one embodiment of the present invention, the elastic modulus of the second base film at 23° C. is preferably 2500-6000 MPa. When the elastic modulus of the second base film is within the above range, it is easy to ensure the peelability when peeling the second base film, and it is easy to achieve good bonding to the substrate. In the present invention, the elastic modulus of the second base film at 23° C. is more preferably 3000 MPa or more, still more preferably 3500 MPa or more, and more preferably 5500 MPa or less.

The elastic modulus of the base film can be measured using a tensile tester. Specifically, it can be measured, for example, by the method described in Examples below.

The thickness of the first base film may be appropriately determined according to the material of the base film, the elastic modulus of the base film, the structure of the layer adjacent to the base film, etc., but is preferably 30 to 120 μm. . When the thickness of the first base film is within the above range, it becomes easier to effectively reinforce the laminate structure that is transferred to the substrate by peeling the second base film, and it is possible to prevent lamination misalignment and wrinkles. A high inhibitory effect can be expected. From the viewpoint of further enhancing such effects, the thickness of the first base film may be preferably 30 µm or more, more preferably 50 µm or more, still more preferably 70 µm or more, and more preferably 120 µm or less, and still more preferably It is 100 μm or less.

The thickness of the second base film is not particularly limited, and may be appropriately determined according to the structure of the base film, the structure of the layer adjacent to the base film, etc. From the viewpoint of surface quality, it is preferably 20 μm or more, more preferably 30 μm or more, and preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less. In the optical laminate of the present invention, the thicknesses of the first base film and the second base film may be the same or different.
The thickness of the base film can be measured by a laser microscope, film thickness meter, or the like, and the thickness of each layer such as a polarizing layer and a retardation layer constituting the optical laminate and the thickness of the film can be measured in the same way.

For the first base film and the second base film, for example, conventionally known resin films or the like in the field of optical films can be used. Examples of resins constituting the first base film and the second base film include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin-based resins; polyvinyl alcohol; polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. polymethacrylates; polyacrylates; cellulosic resins such as triacetylcellulose, diacetylcellulose and cellulose acetate propionate; polycarbonates; polysulfones; plastics such as Among them, at least one selected from cellulose resins, cyclic olefin resins, and polyethylene terephthalate resins is preferable from the viewpoint of smoothness and quality as a coating substrate. These may be used alone or in combination of two or more. Such a resin can be formed into a resin film by known means such as a solvent casting method and a melt extrusion method. The first base film and the second base film may be the same or different. In addition, in this specification, when simply describing the "base film", the "base film" includes the first base film and the second base film.

In order to make it easier to impart the desired releasability and adhesion to the base film surface, the base film surface is modified by corona treatment, plasma treatment, flame treatment, etc. depending on the structure of the adjacent layers. may be applied. In the optical layered body of the present invention, when the first substrate film and the second substrate film are subjected to surface modification treatment, the treatment methods may be the same or different.

A layer having a function of controlling the peeling force when peeling the substrate film from the optical layered body (hereinafter also referred to as “peeling force adjusting layer”) is provided on the side of the second substrate film adjacent to the stress relaxation layer. may be provided. The release force adjusting layer contains, for example, a component that can adjust the adhesion of the second base film to the second stress relaxation layer laminated on the base film on the surface of the resin film that will be the second base film. It can be formed by applying a composition for forming a peel force adjusting layer. For the release force adjusting layer, conventionally known materials in this field can be used as long as the desired release force can be secured. Examples of the composition for forming the release force adjusting layer that can form the release force adjusting layer in the present invention include, for example, a solution containing a silane compound; a solution containing silica powder; a curable resin composition; Compositions containing release materials such as alkyl-based materials and fatty acid amide-based materials are included. Among them, it is preferable to use a solution containing a silane compound from the viewpoint of easily forming a thin layer that can impart a desired peeling force.

Silane compounds that can constitute the release force adjusting layer include, for example, silicon polymers such as polysilane, silicone resins such as silicone oils and silicone resins, and organic and inorganic silane compounds such as silicone oligomers, silsessiloxanes and alkoxysilanes. and, more specifically, nonionic compounds containing Si elements such as silane coupling agents. These silane compounds may be used singly or in combination of two or more. Among them, silane coupling agents are preferred.

The silane coupling agent is a silane compound having at least one functional group selected from the group consisting of a vinyl group, an amino group, a ureido group, a mercapto group, a (meth)acryloyl group, an isocyanate group, an imidazole group and an epoxy group. and more preferably a Si element-containing compound having at least one functional group and at least one alkoxysilyl group or silanol group. A vinyl group, an amino group, a ureido group, a mercapto group, a (meth)acryloyl group, an isocyanate group, an imidazole group and an epoxy group have polarity. It is possible to control the adhesion with. From this point of view, the silane coupling agent is preferably a silane coupling agent having an alkoxysilyl group and the at least one functional group. In addition, the functional group may have an appropriate substituent or protective group in order to control the reactivity of the silane coupling agent.

Silane coupling agents include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2- aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, and 3- Glycidoxypropylethoxydimethylsilane can be mentioned.

Commercially available silane coupling agents may also be used, such as KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001, KBM-1003, KBE-1003, KBM-303, KBM-402, KBM- 403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103, KBM-602, KBM-603, KBM-903, KBE-903, Silane couplings from Shin-Etsu Chemical Co., Ltd. such as KBE-9103, KBM-573, KBM-575, KBM-9659, KBE-585, KBM-802, KBM-803, KBE-846, and KBE-9007 agents.

A layer containing a silane compound that functions as a peel force adjusting layer can be formed, for example, from a silane compound-containing solution obtained by mixing and dissolving a silane compound in an appropriate solvent.

The solvent used for the silane compound-containing solution can be appropriately selected according to the solubility of the silane compound used. Specific examples include water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, alcohol solvents such as propylene glycol monomethyl ether, ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone. , propylene glycol methyl ether acetate, ethyl lactate and other ester solvents, acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, methyl isobutyl ketone and other ketone solvents, pentane, hexane, heptane and other aliphatic hydrocarbon solvents, toluene , aromatic hydrocarbon solvents such as xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents can be used alone or in combination of two or more.

The content of the silane compound in the silane compound-containing solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, relative to the total mass of the silane compound-containing solution, from the viewpoint of easy control of the peeling force. , more preferably 0.2% by mass or more. The content of the silane compound is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, relative to the total mass of the silane compound-containing solution.

The layer containing a silane compound that functions as a release force adjusting layer is formed by, for example, applying a silane compound-containing solution to the surface of the second substrate film on which the release force adjusting layer is to be formed, and then drying and removing the solvent. be able to.

Examples of the method of applying the silane compound-containing solution to the surface on which the release force adjusting layer is to be formed include spin coating, extrusion, gravure coating, die coating, bar coating, applicator method, and the like. Well-known methods, such as printing methods, such as a flexography method, are mentioned.

Examples of the drying method for removing the solvent contained in the coating film obtained from the silane compound-containing solution include natural drying, ventilation drying, heat drying and reduced pressure drying. Conditions such as drying temperature and drying time can be appropriately determined according to the composition of the silane compound-containing solution, the material of the substrate film, and the like.

The thickness of the layer containing a silane compound that functions as a peel force adjusting layer is usually 10 nm to 1000 nm, preferably 10 nm to 500 nm, more preferably 30 nm to 300 nm.

[First Stress Relief Layer and Second Stress Relief Layer]
The optical laminate of the present invention has a first stress relaxation layer on the polarizing layer side of the first base film and a second stress relaxation layer on the retardation layer side of the second base film. In the present invention, the stress relaxation layer is a layer formed on the polarizing layer side surface of the first base film and the retardation layer side surface of the second base film, It means a layer having a function of relieving the stress applied to the optical layered body when the film is peeled off. In the present invention, the first substrate film and the second substrate film constitute an optical laminate via a stress relaxation layer, respectively, and one of the laminate structures to be incorporated (transferred) into the display device. A first stress relieving layer laminated with the base film is present on the outer layer, and a second stress relieving layer is present on the other outer layer. In the optical laminate of the present invention, such a structure increases the strength of the thin laminate structure to be transferred, and wrinkles that may occur when the second base film is peeled off and transferred to the substrate. Excellent effect in suppressing misalignment and generation of air bubbles. Although the reason for this is not clear, the strength of the thin laminate structure to be transferred is increased by having the above structure, and the stress applied to the optical laminate when the substrate film is peeled off from the optical laminate is reduced. Since the stress relaxation layers interact and relax, the effect of suppressing the occurrence of lamination misalignment, wrinkles, etc., is greater than that of an optical layered body in which no stress relaxation layer exists or in which a stress relaxation layer exists only on one side. considered to be higher. In order to sufficiently obtain such effects, in the optical layered body of the present invention, the first base film and the first stress relieving layer are preferably arranged adjacent to each other. Moreover, it is preferable that the second base film and the second stress relieving layer are arranged adjacent to each other or with only the peel force adjusting layer interposed therebetween. In this specification, when the term "stress relaxation layer" is simply used, the "stress relaxation layer" includes the first stress relaxation layer and the second stress relaxation layer.

The stress relieving layer is a layer capable of relieving the stress generated in the optical layered body when the base film is peeled off. The second stress relieving layer is a layer capable of relieving the stress described above, and is a layer that functions as an adhesive layer for adhering to an object to be transferred such as a substrate or a front plate after peeling off the base film. Preferably. The stress relieving property of the stress relieving layer and the adhesiveness to the transferred material can be controlled by the types of components constituting the stress relieving layer, their content ratios, thickness and the like. A stress relieving layer having such a function can be prepared using conventionally known materials in the relevant field. For example, (meth)acrylic, rubber, urethane, ester, silicone, and polyvinyl ether-based compositions (hereinafter also referred to as “compositions for forming stress relaxation layers”) containing resins as main components are mentioned. Above all, from the viewpoint of excellent transparency, adhesiveness, weather resistance, heat resistance, etc., the stress relaxation layer is preferably formed from a composition containing a (meth)acrylic resin as a base polymer.

Examples of the (meth)acrylic resin (base polymer) used in the composition for forming the stress relaxation layer include butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and (meth)acrylic Polymers or copolymers containing one or more of (meth)acrylic acid esters such as 2-ethylhexyl acid as monomers are preferably used. Preferably, the base polymer is copolymerized with a polar monomer. Polar monomers include, for example, (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, (meth)acrylamide, N,N- Monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as dimethylaminoethyl (meth)acrylate and glycidyl (meth)acrylate, can be mentioned.

In one embodiment of the present invention, the structural unit derived from the (meth)acrylic acid ester in the (meth)acrylic resin constituting the stress relaxation layer is is preferably 80 to 99.9% by mass, more preferably 85% by mass or more, and still more preferably 90% by mass or more. Further, when the (meth)acrylic resin contains a structural unit derived from a polar monomer, the structural unit derived from the polar monomer is It is preferably 0.1 to 10% by mass, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, and more preferably 8% by mass or less.

The (meth)acrylic resin that constitutes the stress relaxation layer can be produced by various known methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. A polymerization initiator is usually used in the production of this acrylic resin. The content of the polymerization initiator is preferably 0.001 to 5 parts by mass with respect to a total of 100 parts by mass of all monomers used for producing the (meth)acrylic resin.

A thermal polymerization initiator, a photopolymerization initiator, or the like is used as the polymerization initiator. Examples of thermal polymerization initiators include 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile), 1,1′-azobis(cyclohexane-1-carbonitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2′-azobis(2-methylpropio azo compounds such as 2,2′-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide organic compounds such as oxides, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, and (3,5,5-trimethylhexanoyl) peroxide. Peroxides; inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide; Examples of photopolymerization initiators include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone and the like.

When the acrylic resin is prepared by a solution polymerization method, desired monomers and an organic solvent are mixed, a thermal polymerization initiator is added under a nitrogen atmosphere, and the mixture is stirred at 40 to 90°C, preferably 50 to 80°C. You can mention how to do it. Also, in order to control the reaction, the monomers and polymerization initiator may be added continuously or intermittently during the polymerization, or may be added in a state of being dissolved in an organic solvent. Examples of organic solvents include aromatic hydrocarbon solvents such as toluene and xylene; ester solvents such as ethyl acetate and butyl acetate; aliphatic alcohol solvents such as propyl alcohol and isopropyl alcohol; and ketone-based solvents such as methyl isobutyl ketone and the like can be used.

The stress relieving layer may contain only the acrylic resin, or may be formed using a cross-linking agent in combination. The cross-linking agent is a metal ion having a valence of 2 or more, which forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound, which forms an amide bond with a carboxyl group; Examples include epoxy compounds and polyols that form ester bonds with carboxyl groups; and polyisocyanate compounds that form amide bonds with carboxyl groups.

In addition to the acrylic resin component, the stress relaxation layer may optionally contain components useful for controlling the peelability and adhesion between the stress relaxation layer and adjacent layers. Examples of such components include isocyanate compounds, silane compounds, antistatic components, and the like. When the composition for forming a stress relaxation layer contains these components, the content thereof may be appropriately determined according to the components to be blended, the desired effects, and the like.

In one embodiment of the present invention, the first stress relieving layer contains useful ingredients as described above such that the side of the layer opposite the first substrate film is peelable from the adjacent layer. preferably configured. As another method, for example, the first substrate film may be appropriately subjected to surface treatment or the like so as to increase the adhesion between the first substrate film and the first stress relaxation layer.
On the other hand, the second stress relieving layer is a layer that is incorporated inside the display device after peeling off the second base film. It is preferably a layer laminated with adhesion.

For the stress relaxation layer, for example, a stress relaxation layer-forming composition obtained by dissolving the above-mentioned acrylic resin in a solvent as a main component is bar-coated on the base film or the release force adjustment layer on which the stress relaxation layer is to be laminated. It can be provided by a method of applying and drying by a method or the like. Examples of the solvent include those exemplified in the preparation method of the acrylic resin.

The thickness of the stress relieving layer may be appropriately determined according to the configuration of the stress relieving layer, the configuration and size of the display device, and the like.
In one embodiment of the present invention, the thickness of each of the first stress relaxation layer and the second stress relaxation layer is preferably 5 to 80 μm, more preferably 10 μm or more, still more preferably 15 μm or more, and more It is preferably 50 μm or less, more preferably 30 μm or less. The thickness of the first stress relieving layer and the thickness of the second stress relieving layer may be the same or different.

[Polarizing layer]
In the present invention, the polarizing layer is a layer (polarizer) having a polarizing function. The polarizing layer contains a dichroic dye, which is a dye having anisotropic absorption, and is advantageous for thinning the optical layered body. It is a cured layer formed from a polymerizable liquid crystal composition (hereinafter also referred to as a "polarizing layer-forming composition") containing a liquid crystal compound of a kind, preferably containing a polymerizable liquid crystal compound and a dichroic dye. preferable.

The polymerizable liquid crystal compound (hereinafter also referred to as "polymerizable liquid crystal compound (A)") contained in the composition for forming the polarizing layer of the present invention is a compound having at least one polymerizable group. Here, the term "polymerizable group" refers to a group that can participate in a polymerization reaction due to an active radical generated from a polymerization initiator, an acid, or the like. Examples of the polymerizable group possessed by the polymerizable liquid crystal compound (A) include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, (meth)acryloyl group, oxiranyl group, and oxetanyl group. etc. Among them, a radically polymerizable group is preferred, a (meth)acryloyl group, a vinyl group, and a vinyloxy group are more preferred, and a (meth)acryloyl group is even more preferred. When the polymerizable liquid crystal compound forming the polarizing layer has the same functional group (polymerizable group) as the compound forming the alignment film for forming the polarizing layer described later, such as a (meth)acryloyl group, The compatibility between the alignment film and the polarizing layer is high, and excellent adhesion between the layers can be exhibited.

In the present invention, the polymerizable liquid crystal compound (A) is preferably a compound exhibiting smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizing layer with a high degree of orientational order can be formed. From the viewpoint of realizing a higher degree of alignment order, the liquid crystal state exhibited by the polymerizable liquid crystal compound (A) is more preferably a high-order smectic phase (high-order smectic liquid crystal state). Here, the higher order smectic phase includes smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase and smectic L phase. Among these, smectic B phase, smectic F phase and smectic I phase are more preferable. Thermotropic liquid crystals or lyotropic liquid crystals may be used as liquid crystals, but thermotropic liquid crystals are preferred because they allow precise film thickness control. Moreover, the polymerizable liquid crystal compound (A) may be a monomer, but may be an oligomer or polymer in which a polymerizable group is polymerized.

The polymerizable liquid crystal compound (A) is not particularly limited as long as it is a liquid crystal compound having at least one polymerizable group, and known polymerizable liquid crystal compounds can be used, but compounds exhibiting smectic liquid crystallinity are preferred. Examples of such a polymerizable liquid crystal compound include compounds represented by the following formula (A1) (hereinafter sometimes referred to as "polymerizable liquid crystal compound (A1)").
U ¹ -V ¹ -W ¹ -(X ¹ -Y ¹ ) _n -X ² -W ² -V ² -U ² (A1)
[In the formula (A1),
X ¹ and X ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein the divalent aromatic group or divalent alicyclic hydrocarbon A hydrogen atom contained in the group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group. A carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom. However, at least one of X ¹ and X ² is an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane-1,4-diyl group.
Y ¹ is a single bond or a divalent linking group.
n is 1 to 3, and when n is 2 or more, multiple X ^1s may be the same or different. X ² may be the same as or different from any or all of the plurality of X ¹ 's. Moreover, when n is 2 or more, the plurality of Y ¹ may be the same or different. From the viewpoint of liquid crystallinity, n is preferably 2 or more.
U1 represents ^a hydrogen atom or a polymerizable group.
^U2 represents a polymerizable group.
W ¹ and W ² are each independently a single bond or a divalent linking group.
V ¹ and V ² each independently represent an optionally substituted alkanediyl group having 1 to 20 carbon atoms, and —CH ₂ — constituting the alkanediyl group is —O—, -CO-, -S- or NH- may be substituted. ]

In the polymerizable liquid crystal compound (A1), X ¹ and X ² are each independently preferably a 1,4-phenylene group optionally having a substituent, or a 1,4-phenylene group optionally having a substituent, or cyclohexane-1,4-diyl group, and at least one of X ¹ and X ² is a 1,4-phenylene group optionally having a substituent, or a 1,4-phenylene group optionally having a substituent cyclohexane-1,4-diyl group, preferably trans-cyclohexane-1,4-diyl group. Optionally substituted 1,4-phenylene group or optionally substituted cyclohexane-1,4-diyl group may have a methyl group, ethyl and alkyl groups having 1 to 4 carbon atoms such as butyl group, cyano group and halogen atoms such as chlorine atom and fluorine atom. It is preferably unsubstituted.

Further, the polymerizable liquid crystal compound (A1) is represented by the formula (A1-1) in the formula (A1):
-(X ¹ -Y ¹ ) _n -X ² - (A1-1)
[In the formula, X ¹ , Y ¹ , X ² and n each have the same meaning as above. ]
[hereinafter, also referred to as partial structure (A1-1)] has an asymmetric structure, because it facilitates smectic liquid crystallinity.
Examples of the polymerizable liquid crystal compound (A1) in which the partial structure ⁽ A1-1) is ^an asymmetric structure include, for example, a polymerizable liquid crystal compound (A1 ). Also, a compound in which n is 2, two Y ^1s have the same structure, two X ^1s have the same structure, and one X ² has a different structure from these two X ^1s Polymerizable liquid crystal compound (A1), X ¹ bonded to W ¹ of two X ¹ has a different structure from the other X ¹ and X ² , and the other X ¹ and X ² have the same structure A polymerizable liquid crystal compound (A1) is also included. Furthermore, a compound in which n is 3, three Y ^1s have the same structure as each other, and any one of the three X ^1s and one X ² has a different structure from all the other three. liquid crystal compound (A1).

Y ¹ is -CH ₂ CH ₂ -, -CH ₂ O-, -CH ₂ CH ₂ O-, -COO-, -OCOO-, a single bond, -N=N-, -CR ^a =CR ^b -, -C≡C-, -CR ^a =N- or -CO-NR ^a - are preferred. R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y ¹ is more preferably —CH ₂ CH ₂ —, —COO—, or a single bond, and when there are multiple Y ^1s , Y ¹ bonded to X ² is —CH ₂ CH ₂ — or CH ₂ O— is more preferred. When X ¹ and X ² all have the same structure, it is preferred that there are two or more Y ¹ with different binding modes. When ^a plurality of Y1's with different bonding methods exist, the structure is asymmetrical, and smectic liquid crystallinity tends to occur.

^U2 is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, preferably a polymerizable group. Both U ¹ and U ² are preferably polymerizable groups, and preferably both are radically polymerizable groups. Examples of the polymerizable group include the same groups as those exemplified above as the polymerizable group possessed by the polymerizable liquid crystal compound (A). The polymerizable group represented by U ¹ and the polymerizable group represented by U ² may be different from each other, but are preferably groups of the same type, and at least one of U ¹ and U ² is (meta) It is preferably an acryloyl group, and more preferably both are (meth)acryloyl groups. The polymerizable group may be in a polymerized state or in an unpolymerized state, preferably in an unpolymerized state.

The alkanediyl groups represented by V ¹ and V ² include methylene, ethylene, propane-1,3-diyl, butane-1,3-diyl, butane-1,4-diyl, pentane- 1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, decane-1,10-diyl group, tetradecane-1,14-diyl group and icosane-1,20-diyl groups. V ¹ and V ² are preferably alkanediyl groups having 2 to 12 carbon atoms, more preferably alkanediyl groups having 6 to 12 carbon atoms.

Examples of the substituent optionally possessed by the alkanediyl group include a cyano group and a halogen atom. is more preferred.

W ¹ and W ² are each independently preferably a single bond, -O-, -S-, -COO- or -OCOO-, more preferably a single bond or -O-.

The polymerizable liquid crystal compound (A) is not particularly limited as long as it is a polymerizable liquid crystal compound having at least one polymerizable group, and known polymerizable liquid crystal compounds can be used. Preferably, as a structure that tends to exhibit smectic liquid crystallinity, it is preferable to have an asymmetric molecular structure in the molecular structure, specifically polymerizable having the following partial structures (Aa) to (Ai) A polymerizable liquid crystal compound that is a liquid crystal compound and exhibits smectic liquid crystallinity is more preferable. It is more preferable to have a partial structure of (Aa), (Ab) or (Ac) from the viewpoint of easily exhibiting high-order smectic liquid crystallinity. In (Aa) to (Ai) below, * represents a bond (single bond).

Specific examples of the polymerizable liquid crystal compound (A) include compounds represented by formulas (A-1) to (A-25). When the polymerizable liquid crystal compound (A) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans form.

Among these, formula (A-2), formula (A-3), formula (A-4), formula (A-5), formula (A-6), formula (A-7), formula (A- 8), at least one selected from the group consisting of compounds represented by formula (A-13), formula (A-14), formula (A-15), formula (A-16) and formula (A-17) Seeds are preferred. As the polymerizable liquid crystal compound (A), one type may be used alone, or two or more types may be used in combination.

The polymerizable liquid crystal compound (A) is described, for example, in Lub et al., Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), or a known method described in Japanese Patent No. 4,719,156.

In the present invention, the composition for forming a polarizing layer may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound (A). The ratio of the polymerizable liquid crystal compound (A) to the total mass of all the polymerizable liquid crystal compounds contained in the composition is preferably 51% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass. % or more.

When the polarizing layer-forming composition contains two or more polymerizable liquid crystal compounds (A), at least one of them may be the polymerizable liquid crystal compound (A1), and all of them may be polymerizable liquid crystal compounds (A1 ). By combining a plurality of polymerizable liquid crystal compounds, it may be possible to temporarily maintain liquid crystallinity even at temperatures below the liquid crystal-crystal phase transition temperature.

The content of the polymerizable liquid crystal compound in the polarizing layer-forming composition is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, based on the solid content of the polarizing layer-forming composition. Yes, more preferably 70 to 99% by mass. When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be high. The term "solid content" as used herein refers to a component obtained by removing volatile components such as solvents from the composition for forming a polarizing layer. It refers to the components of the target composition excluding volatile components such as solvents.

In the present invention, the polarizing layer-forming composition that forms the polarizing layer usually contains a dichroic dye. Here, the term "dichroic dye" means a dye having different absorbance in the long-axis direction and the short-axis direction of the molecule. The dichroic dye that can be used in the present invention is not particularly limited as long as it has the above properties, and may be a dye or a pigment. Also, two or more dyes or pigments may be used in combination, or a dye and a pigment may be used in combination. Moreover, the dichroic dye may have polymerizability or may have liquid crystallinity.

Dichroic dyes preferably have a maximum absorption wavelength (λ _MAX ) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes and anthraquinone dyes.

Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakis azo dyes and stilbene azo dyes, and preferred are bisazo dyes and trisazo dyes. (I)”).
K ¹ (-N=N-K ² ) _p -N=N-K ³ (I)
[In formula (I), K ¹ and K ³ are, independently of each other, a phenyl group optionally having substituent(s), a naphthyl group optionally having substituent(s), It represents a phenyl benzoic acid ester group or a monovalent heterocyclic group which may have a substituent. K ² is a p-phenylene group optionally having substituents, a naphthalene-1,4-diyl group optionally having substituents, 4,4′- optionally having substituents represents a stilbenylene group or an optionally substituted divalent heterocyclic group; p represents an integer from 0 to 4; When p is an integer of ² or more, multiple K2 may be the same or different. -N=N-bonds may be replaced with -C=C-, -COO-, -NHCO- and -N=CH-bonds within the range of absorption in the visible region. ]

Examples of monovalent heterocyclic groups include groups obtained by removing one hydrogen atom from heterocyclic compounds such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. The divalent heterocyclic group includes a group obtained by removing two hydrogen atoms from the above heterocyclic compound.

Phenyl group, naphthyl group, phenyl benzoic acid ester group and monovalent heterocyclic group for K ¹ and K ³ , and p-phenylene group, naphthalene-1,4-diyl group and 4,4'-stilbenylene group for K ² And the substituent optionally possessed by the divalent heterocyclic group includes an alkyl group having 1 to 20 carbon atoms, an alkyl group having a polymerizable group and having 1 to 20 carbon atoms, an alkenyl group having 1 to 4 carbon atoms; a methoxy group; , ethoxy group, alkoxy group having 1 to 20 carbon atoms such as butoxy group; alkoxy group having 1 to 20 carbon atoms having a polymerizable group; fluorinated alkyl group having 1 to 4 carbon atoms such as trifluoromethyl group; cyano group a nitro group; a halogen atom; an amino group, a diethylamino group, a substituted or unsubstituted amino group such as a pyrrolidino group (a substituted amino group is an amino group having one or two alkyl groups having 1 to 6 carbon atoms, a polymerizable means an amino group having one or two alkyl groups having 1 to 6 carbon atoms, or an amino group having two substituted alkyl groups bonded together to form an alkanediyl group having 2 to 8 carbon atoms An unsubstituted amino group is —NH _2. ) and the like. In addition, a (meth)acryloyl group, a (meth)acryloyloxy group, etc. are mentioned as said polymerizable group.

［式（Ｉ－１）～（Ｉ－８）中、
Ｂ^１～Ｂ^３０は、互いに独立して、水素原子、炭素数１～６のアルキル基、炭素数１～６のアルケニル基、炭素数１～４のアルコキシ基、シアノ基、ニトロ基、置換または無置換のアミノ基（置換アミノ基および無置換アミノ基の定義は前記のとおり）、塩素原子またはトリフルオロメチル基を表わす。
ｎ１～ｎ４は、互いに独立に０～３の整数を表わす。
ｎ１が２以上である場合、複数のＢ^２は互いに同一でも異なっていてもよく、
ｎ２が２以上である場合、複数のＢ^６は互いに同一でも異なっていてもよく、
ｎ３が２以上である場合、複数のＢ^９は互いに同一でも異なっていてもよく、
ｎ４が２以上である場合、複数のＢ^１４は互いに同一でも異なっていてもよい。］ Among compounds (I), compounds represented by any one of the following formulas (I-1) to (I-8) are preferred.

[In the formulas (I-1) to (I-8),
B ¹ to B ³⁰ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, substituted or represents an unsubstituted amino group (the definitions of substituted amino group and unsubstituted amino group are as described above), chlorine atom or trifluoromethyl group;
n1 to n4 each independently represents an integer of 0 to 3;
When n1 is ² or more, the plurality of B2 may be the same or different,
When n2 is 2 or more, the plurality of ^B6 may be the same or different,
When n3 is ² or more, multiple B9 may be the same or different,
When n4 is 2 or more, the plurality of ^B14 may be the same or different. ]

［式（Ｉ－９）中、
Ｒ^１～Ｒ^８は、互いに独立して、水素原子、－Ｒ^ｘ、－ＮＨ_２、－ＮＨＲ^ｘ、－ＮＲ^ｘ _２、－ＳＲ^ｘまたはハロゲン原子を表わす。
Ｒ^ｘは、炭素数１～６のアルキル基または炭素数６～１２のアリール基を表わす。］ As the anthraquinone dye, a compound represented by formula (I-9) is preferable.

[In the formula (I-9),
R ¹ to R ⁸ independently represent a hydrogen atom, —R ^x , —NH ₂ , —NHR ^x , —NR ^x ₂ , —SR ^x or a halogen atom.
R ^x represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

［式（Ｉ－１０）中、
Ｒ^９～Ｒ^１５は、互いに独立して、水素原子、－Ｒ^ｘ、－ＮＨ_２、－ＮＨＲ^ｘ、－ＮＲ^ｘ _２、－ＳＲ^ｘまたはハロゲン原子を表わす。
Ｒ^ｘは、炭素数１～６のアルキル基または炭素数６～１２のアリール基を表わす。］ As the oxazone dye, a compound represented by formula (I-10) is preferable.

[In the formula (I-10),
R ⁹ to R ¹⁵ each independently represent a hydrogen atom, —R ^x , —NH ₂ , —NHR ^x , —NR ^x ₂ , —SR ^x or a halogen atom.
R ^x represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

［式（Ｉ－１１）中、
Ｒ^１６～Ｒ^２３は、互いに独立して、水素原子、－Ｒ^ｘ、－ＮＨ_２、－ＮＨＲ^ｘ、－ＮＲ^ｘ _２、－ＳＲ^ｘまたはハロゲン原子を表わす。
Ｒ^ｘは、炭素数１～６のアルキル基または炭素数６～１２のアリール基を表わす。］
式（Ｉ－９）、式（Ｉ－１０）および式（Ｉ－１１）において、Ｒ^ｘの炭素数１～６のアルキル基としては、メチル基、エチル基、プロピル基、ブチル基、ペンチル基およびヘキシル基等が挙げられ、炭素数６～１２のアリール基としては、フェニル基、トルイル基、キシリル基およびナフチル基等が挙げられる。 As the acridine dye, a compound represented by formula (I-11) is preferable.

[In the formula (I-11),
R ¹⁶ to R ²³ each independently represent a hydrogen atom, —R ^x , —NH ₂ , —NHR ^x , —NR ^x ₂ , —SR ^x or a halogen atom.
R ^x represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]
In formula (I-9), formula (I-10) and formula (I-11), the alkyl group having 1 to 6 carbon atoms for R ^x includes a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group. and hexyl group, and the aryl group having 6 to 12 carbon atoms includes phenyl group, toluyl group, xylyl group, naphthyl group and the like.

［式（Ｉ－１２）中、
Ｄ^１およびＤ^２は、互いに独立に、式（Ｉ－１２ａ）～式（Ｉ－１２ｄ）のいずれかで表される基を表わす。

ｎ５は１～３の整数を表わす。］

［式（Ｉ－１３）中、
Ｄ^３およびＤ^４は、互いに独立に、式（Ｉ－１３ａ）～式（１－１３ｈ）のいずれかで表される基を表わす。

ｎ６は１～３の整数を表わす。］ As the cyanine dye, a compound represented by formula (I-12) and a compound represented by formula (I-13) are preferable.

[In the formula (I-12),
D ¹ and D ² each independently represent a group represented by any one of formulas (I-12a) to (I-12d).

n5 represents an integer of 1-3. ]

[In the formula (I-13),
D ³ and D ⁴ each independently represent a group represented by any one of formulas (I-13a) to (1-13h).

n6 represents an integer of 1-3. ]

Among these dichroic dyes, azo dyes have high linearity and are suitable for producing a polarizing layer having excellent polarizing performance. Therefore, in one embodiment of the present invention, the dichroic dye contained in the polarizing layer-forming composition for forming the polarizing layer is preferably an azo dye.

In the present invention, the weight average molecular weight of the dichroic dye is usually 300-2000, preferably 400-1000.

In one embodiment of the present invention, the dichroic dye contained in the polarizing layer-forming composition for forming the polarizing layer is preferably hydrophobic. When the dichroic dye is hydrophobic, the compatibility between the dichroic dye and the polymerizable liquid crystal compound is improved, the dichroic dye and the polymerizable liquid crystal compound form a uniform phase state, and the degree of orientational order is high. can be obtained. In the present invention, the hydrophobic dichroic dye means a dye having a solubility of 1 g or less in 100 g of water at 25°C.

The content of the dichroic dye in the polarizing layer-forming composition can be appropriately determined according to the type of the dichroic dye used, etc., but is preferably 0.1 to 0.1 parts per 100 parts by mass of the polymerizable liquid crystal compound. It is 50 parts by mass, more preferably 0.1 to 20 parts by mass, still more preferably 0.1 to 12 parts by mass. When the content of the dichroic dye is within the above range, the alignment of the polymerizable liquid crystal compound is less likely to be disturbed, and a polarizing layer having a high degree of alignment order can be obtained.

In the present invention, the polarizing layer forming composition for forming the polarizing layer may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating the polymerization reaction of the polymerizable liquid crystal compound, and is preferably a photopolymerization initiator because it can initiate the polymerization reaction under lower temperature conditions. Specifically, photopolymerization initiators capable of generating active radicals or acids by the action of light may be mentioned, and among these, photopolymerization initiators capable of generating radicals by the action of light are preferred. A polymerization initiator can be used individually or in combination of 2 or more types.

As the photopolymerization initiator, known photopolymerization initiators can be used. For example, photopolymerization initiators that generate active radicals include self-cleavage photopolymerization initiators and hydrogen abstraction photopolymerization initiators. There is
Self-cleavage photopolymerization initiators include self-cleavage benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. Available. In addition, as a hydrogen abstraction type photopolymerization initiator, hydrogen abstraction type benzophenone compounds, benzoin ether compounds, benzyl ketal compounds, dibenzosuberone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, halogenoacetophenone compounds. compounds, dialkoxyacetophenone-based compounds, halogenobisimidazole-based compounds, halogenotriazine-based compounds, triazine-based compounds, and the like can be used.

As photopolymerization initiators that generate acid, iodonium salts, sulfonium salts, and the like can be used.

Among these, a reaction at a low temperature is preferable from the viewpoint of preventing dissolution of the dye, and a self-cleavage photopolymerization initiator is preferable from the viewpoint of reaction efficiency at a low temperature. compounds and oxime ester compounds are preferred.

Specific examples of photopolymerization initiators include the following.
Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether;
2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethan-1-one, 2-hydroxy-2-methyl-1-[4-(2- Hydroxyacetophenones such as hydroxyethoxy)phenyl]propan-1-one, oligomers of 1-hydroxycyclohexylphenyl ketone and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one system compound;
α-Aminoacetophenones such as 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one system compound;
1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3 -Oxime ester compounds such as yl]-, 1-(O-acetyloxime);
Acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide;
benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenylsulfide, 3,3′,4,4′-tetra(tert-butylperoxycarbonyl)benzophenone and 2,4, Benzophenone compounds such as 6-trimethylbenzophenone;
Dialkoxyacetophenone compounds such as diethoxyacetophenone;
2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3, 5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5 -methylfuran-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5- Triazines, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine and 2,4-bis(trichloromethyl)-6- triazine compounds such as [2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine; The photopolymerization initiator may be appropriately selected, for example, from the above photopolymerization initiators in relation to the polymerizable liquid crystal compound contained in the polarizing layer-forming composition.

Moreover, you may use a commercially available photoinitiator. Commercially available polymerization initiators include Irgacure® 907, 184, 651, 819, 250 and 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by BASF); Omnirad BCIM, Esacure 1001M, Esacure KIP160 (from IDM Resins B.V.); Seikuol® BZ, Z, and BEE (from Seiko Chemical Co., Ltd.); kayacure® BP100, and UVI-6992 (from Dow · Chemical Co., Ltd.); Adeka Optomer SP-152, N-1717, N-1919, SP-170, Adeka Arkles NCI-831, Adeka Arkles NCI-930 (manufactured by ADEKA Co., Ltd.); TAZ-A, and TAZ-PP (manufactured by Nihon SiberHegner Co., Ltd.); and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.);

The content of the polymerization initiator in the polarizing layer-forming composition for forming the polarizing layer is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. parts, more preferably 2 to 8 parts by mass, particularly preferably 4 to 8 parts by mass. When the content of the polymerization initiator is within the above range, the polymerization reaction of the polymerizable liquid crystal compound can be carried out without greatly disturbing the orientation of the polymerizable liquid crystal compound.

In the present invention, the polymerization rate of the polymerizable liquid crystal compound is preferably 60% or more, more preferably 65% or more, and even more preferably 70% or more, from the viewpoint of line contamination and handling during production.

The polarizing layer-forming composition may further contain a photosensitizer. By using a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound can be further accelerated. Examples of photosensitizers include xanthone compounds such as xanthone and thioxanthone (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); phenothiazine and rubrene and the like. Photosensitizers can be used alone or in combination of two or more.

When the polarizing layer-forming composition contains a photosensitizer, the content thereof may be appropriately determined according to the types and amounts of the polymerization initiator and the polymerizable liquid crystal compound, but 100 parts by mass of the polymerizable liquid crystal compound. is preferably from 0.1 to 30 parts by mass, more preferably from 0.5 to 10 parts by mass, and even more preferably from 0.5 to 8 parts by mass.

Moreover, the composition for forming a polarizing layer may contain a leveling agent. The leveling agent has the function of adjusting the fluidity of the composition for forming the polarizing layer and making the coating film obtained by applying the composition for forming the polarizing layer more flat. agents. The leveling agent is preferably at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. A leveling agent can be used individually or in combination of 2 or more types.

Examples of leveling agents mainly composed of polyacrylate compounds include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", and "BYK-358N". , “BYK-361N”, “BYK-380”, “BYK-381” and “BYK-392” (BYK Chemie).

Leveling agents mainly composed of fluorine atom-containing compounds include, for example, "Megafac (registered trademark) R-08", "R-30", "R-90", "F-410", "F-411", "F-443", "F-445", "F-470", "F-471", "F-477", "F-479", " F-482” and “F-483” (DIC Corporation); “Surflon (registered trademark) S-381”, “S-382”, “S-383”, “S-393”, "SC-101", "SC-105", "KH-40" and "SA-100" (AGC Seimi Chemical Co., Ltd.); "E1830", "E5844" (Daikin Fine Chemicals Laboratory Co., Ltd.) "Ftop EF301", "Ftop EF303", "Ftop EF351" and "Ftop EF352" (Mitsubishi Materials Electronic Chemicals Co., Ltd.).

When the polarizing layer-forming composition contains a leveling agent, the content thereof is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. . When the content of the leveling agent is within the above range, the polymerizable liquid crystal compound is easily oriented, unevenness is less likely to occur, and a smoother polarizing layer tends to be obtained.

The polarizing layer-forming composition may contain additives other than the photosensitizer and the leveling agent. Other additives include, for example, antioxidants, release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When the polarizing layer-forming composition contains other additives, the content of the other additives should be more than 0% and 20% by mass or less based on the solid content of the polarizing layer-forming composition. is preferable, more preferably more than 0% and 10% by mass or less.

The polarizing layer-forming composition can be produced by a conventionally known method for preparing a polarizing layer-forming composition. It can be prepared by mixing and stirring additives and the like. In addition, since compounds exhibiting smectic liquid crystallinity generally have high viscosity, a solvent is added to the polarizing layer-forming composition from the viewpoint of improving the coatability of the polarizing layer-forming composition and facilitating the formation of the polarizing layer. Viscosity may be adjusted by

The solvent used in the polarizing layer-forming composition can be appropriately selected according to the solubility of the polymerizable liquid crystal compound and the dichroic dye used. Specifically, for example, alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ- ester solvents such as butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; Examples include aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents can be used alone or in combination of two or more. The content of the solvent is preferably 100 to 1,900 parts by mass, more preferably 150 to 900 parts by mass, and still more preferably 180 to 600 parts by mass, based on 100 parts by mass of the solid content of the polarizing layer-forming composition. Department.

In the present invention, the polarizing layer is preferably a polarizer with a high degree of orientational order. A polarizer with a high degree of orientational order provides a Bragg peak derived from a higher-order structure such as a hexatic phase or a crystal phase in X-ray diffraction measurement. A Bragg peak means a peak derived from a periodic plane structure of molecular orientation. Therefore, the polarizing layer constituting the optical laminate of the present invention preferably exhibits a Bragg peak in X-ray diffraction measurement. That is, in the polarizing layer constituting the optical laminate of the present invention, the polymerizable liquid crystal compound or its polymer is preferably oriented so that the polarizing layer exhibits a Bragg peak in X-ray diffraction measurement. It is more preferable that the molecules of the polymerizable liquid crystal compound are oriented in the direction of absorbing the “horizontal alignment”. In the present invention, a polarizer having a plane period interval of molecular orientation of 3.0 to 6.0 Å is preferred. A high degree of orientational order exhibiting a Bragg peak can be realized by controlling the type of polymerizable liquid crystal compound to be used, the type and amount of dichroic dye, the type and amount of polymerization initiator, and the like.

In the present invention, the polarizing layer is formed by, for example, forming a coating film of a composition for forming a polarizing layer on a substrate or an alignment film described later, removing a solvent from the coating film, and converting a polymerizable liquid crystal compound into a liquid phase. Raising the temperature to the phase transition temperature or higher and then lowering the temperature to cause the phase transition of the polymerizable liquid crystal compound to a liquid crystal phase (smectic phase), and polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal phase. can be obtained by a method comprising

Examples of methods for applying the polarizing layer-forming composition to a substrate or an alignment film include spin coating, extrusion, gravure coating, die coating, bar coating, applicator methods, and flexo coating. well-known methods such as a printing method such as a printing method.

Next, the solvent is removed by drying or the like under conditions in which the polymerizable liquid crystal compound contained in the coating film obtained from the polarizing layer-forming composition is not polymerized, thereby forming a dry coating film. Drying methods include natural drying, ventilation drying, heat drying, and reduced pressure drying.

Further, in order to cause the phase transition of the polymerizable liquid crystal compound to the liquid phase, the temperature is raised to a temperature equal to or higher than the temperature at which the polymerizable liquid crystal compound undergoes phase transition to the liquid phase, and then the temperature is lowered to convert the polymerizable liquid crystal compound to the liquid crystal phase (smectic phase). transfer. Such a phase transition may be carried out after removing the solvent in the coating film, or may be carried out simultaneously with the removal of the solvent.

By polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal state of the polymerizable liquid crystal compound, the polarizing layer is formed as a cured product of the composition for forming the polarizing layer. A photopolymerization method is preferable as the polymerization method. In photopolymerization, the light irradiated to the dry coating film includes the type of polymerizable liquid crystal compound contained in the dry coating film (especially the type of polymerizable group possessed by the polymerizable liquid crystal compound), the type of polymerization initiator and It is appropriately selected according to the amount thereof. Specific examples thereof include at least one kind of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays and γ-rays, and active electron beams. Among them, ultraviolet light is preferable in that it is easy to control the progress of the polymerization reaction and that a widely used photopolymerization apparatus in the field can be used. It is preferable to select the types of the polymerizable liquid crystal compound and the polymerization initiator contained in the polarizing layer-forming composition. The polymerization temperature can also be controlled by light irradiation while cooling the dry coating film with an appropriate cooling means at the time of polymerization. A patterned polarizing layer can also be obtained by performing masking or development during photopolymerization.

As the light source of the active energy ray, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, xenon lamp, halogen lamp, carbon arc lamp, tungsten lamp, gallium lamp, excimer laser, wavelength range 380 ~ LED light sources that emit light at 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, and the like can be used.

The UV irradiation intensity is usually 10 to 3,000 mW/cm ² . The ultraviolet irradiation intensity is preferably in the wavelength range effective for activation of the photopolymerization initiator. The light irradiation time is usually 0.1 second to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, still more preferably 10 seconds to 1 minute. When irradiated once or multiple times with such an irradiation intensity of ultraviolet rays, the cumulative amount of light is 10 to 3,000 mJ/cm ² , preferably 50 to 2,000 mJ/cm ² , more preferably 100 to 1,000 mJ/cm. ² .

By performing photopolymerization, the polymerizable liquid crystal compound is polymerized while maintaining the liquid crystal state of the liquid crystal phase, particularly the smectic phase, preferably the high-order smectic phase, to form the polarizing layer. The polarizing layer obtained by polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal state of the smectic phase is different from the conventional host-guest type polarizing film, that is, the liquid crystal state of the nematic phase, due to the action of the dichroic dye. There is an advantage that the polarizing performance is higher than that of the polarizing layer. In addition, it has the advantage of being superior in strength compared to those coated with only dichroic dyes or lyotropic liquid crystals.

The thickness of the polarizing layer can be appropriately selected according to the display device to which it is applied, and is preferably 0.1 to 5 μm, more preferably 0.3 to 4 μm, still more preferably 0.5 to 3 μm. When the thickness of the polarizing layer is at least the above lower limit, it is easy to prevent the necessary light absorption from becoming impossible, and when it is at most the above upper limit, orientation defects due to a decrease in the orientation ordering force of the orientation film occur. It is easy to suppress the occurrence of

The polarizing layer may be formed on the alignment film. The alignment film has an alignment regulating force that aligns the polymerizable liquid crystal compound in a desired direction, and by applying the polarizing layer-forming composition onto the alignment film, it is easy to obtain a polarizing layer that is aligned with high accuracy. . The alignment film preferably has solvent resistance so that it does not dissolve when the polarizing layer-forming composition is applied or the like, and has heat resistance in heat treatment for removing the solvent and for aligning the polymerizable liquid crystal compound. In the present invention, the alignment film is preferably a photo-alignment film from the viewpoints of accuracy and quality of the alignment angle, water resistance and bending resistance of the optical layered body including the alignment film. The photo-alignment film is also advantageous in that the direction of the alignment regulating force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

The photo-alignment film is usually a composition containing a polymer, oligomer or monomer having a photo-reactive group (hereinafter also referred to as "polymer having a photo-reactive group, etc.") and a solvent (hereinafter referred to as "photo-alignment film forming composition”) is applied onto a substrate or, if necessary, a diffusion prevention layer provided on the substrate, and irradiated with polarized light (preferably polarized UV). As the substrate on which the photo-alignment film is formed, the same substrate film as the optical laminate of the present invention can be used. The polymer or the like contained in the photo-alignment film-forming composition has the same reactive group as the functional group of the polymerizable liquid crystal compound that forms the polarizing layer (e.g., (meth) acryloyl group), Adhesion to the polarizing layer tends to improve.

A photoreactive group refers to a group that exhibits liquid crystal alignment ability upon irradiation with light. Specific examples include groups involved in photoreactions that cause liquid crystal alignment ability, such as orientation induction of molecules caused by light irradiation, isomerization reactions, dimerization reactions, photocrosslinking reactions, photodecomposition reactions, and the like. Among them, a group involved in a dimerization reaction or a photocrosslinking reaction is preferable from the viewpoint of excellent orientation. As the photoreactive group, a group having an unsaturated bond, particularly a double bond is preferable, and a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond Groups having at least one selected from the group consisting of a heavy bond (N=N bond) and a carbon-oxygen double bond (C=O bond) are particularly preferred.

Photoreactive groups having a C=C bond include vinyl groups, polyene groups, stilbene groups, stilbazole groups, stilbazolium groups, chalcone groups and cinnamoyl groups. Photoreactive groups having a C═N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of the photoreactive group having an N=N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. A benzophenone group, a coumarin group, an anthraquinone group, a maleimide group, etc. are mentioned as a photoreactive group which has a C=O bond. These groups may have substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups, and halogenated alkyl groups.

Among them, a photoreactive group that participates in a photodimerization reaction is preferable, the amount of polarized light irradiation required for photoalignment is relatively small, and a photoalignment film having excellent thermal stability and stability over time can be easily obtained. Cinnamoyl and chalcone groups are preferred. As a polymer having a photoreactive group, a polymer having a cinnamoyl group having a cinnamic acid structure at the end of the polymer side chain is particularly preferable.

A photo-alignment inducing layer can be formed, for example, by applying the composition for forming a photo-alignment film onto a substrate or a diffusion prevention layer provided on a substrate. Examples of the solvent contained in the composition include the same solvents as those previously exemplified as solvents that can be used in forming the polarizing layer, and are appropriately selected according to the solubility of the polymer having a photoreactive group. can do.

The content of the polymer or the like having a photoreactive group in the composition for forming a photo-alignment film can be appropriately adjusted depending on the type of the polymer or the like and the thickness of the desired photo-alignment film, but the mass of the composition for forming a photo-alignment film is preferably at least 0.2% by mass, more preferably in the range of 0.3 to 10% by mass. The composition for forming a photo-alignment film may contain a polymer material such as polyvinyl alcohol or polyimide, or a photosensitizer, as long as the properties of the photo-alignment film are not significantly impaired.

The method of applying the composition for forming a photo-alignment film onto the substrate or onto the diffusion prevention layer, and the method of removing the solvent from the composition for forming a photo-alignment film that has been coated include the composition for forming a polarizing layer. The same method as the method of applying to the material and the method of removing the solvent can be used.

Irradiation with polarized light may be in the form of directly irradiating polarized UV to the coating film of the photo-alignment film-forming composition after removing the solvent, or in the form of irradiating polarized light from the substrate side and transmitting the polarized light. . Moreover, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of polarized light to be irradiated is preferably in a wavelength range in which a photoreactive group such as a polymer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) with a wavelength in the range of 250 to 400 nm is particularly preferred. Examples of the light source used for the polarized irradiation include a xenon lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, and an ultraviolet light laser such as KrF or ArF. preferable. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because of their high emission intensity of ultraviolet rays having a wavelength of 313 nm. Polarized UV can be emitted by passing the light from the light source through a suitable polarizer. As such a polarizer, a polarizing filter, a polarizing prism such as Glan-Thompson or Glan-Taylor, or a wire grid type polarizer can be used.

A plurality of regions (patterns) having different liquid crystal alignment directions can be formed by masking the polarized light.

The number average molecular weight of the photo-alignment film is preferably 20,000 to 100,000, more preferably 25,000 or more, more preferably 90,000 or less, still more preferably 80,000 or less. When the number average molecular weight of the photo-alignment film is within the above range, the adhesion to the layer adjacent to the photo-alignment film is likely to be improved. The number average molecular weight of the photo-alignment film can be controlled by adjusting the amount of the monomer used in the composition for forming the photo-alignment film, the type and amount of the polymerization initiator, and the like.
The term "number average molecular weight of the photo-alignment film" as used herein substantially corresponds to the number average molecular weight of the polymer constituting the cured photo-alignment film, and is measured using a measuring instrument such as gel permeation chromatography. is the molecular weight calculated by measuring the cured photo-alignment film itself.

The thickness of the photo-alignment film is preferably 10 to 5000 nm, more preferably 10 to 1000 nm, still more preferably 30 to 300 nm. When the thickness of the photo-alignment film is within the above range, it is possible to exhibit good adhesion at the interface with the polarizing layer and exhibit alignment ordering power, so that the polarizing layer can be formed with high alignment order.

[Diffusion prevention layer]
The optical laminate of the present invention may further include a diffusion prevention layer between the first stress relieving layer and the polarizing layer and/or between the polarizing layer and the adhesive layer. The presence of the anti-diffusion layer between the first stress relaxation layer and the polarizing layer and between the polarizing layer and the adhesive layer effectively prevents the diffusion of the dichroic dye in the polarizing layer to other layers. When the optical layered body of the present invention is incorporated into a display device or the like, deterioration of optical properties over time due to diffusion of the dichroic dye can be suppressed. From the viewpoint of sufficiently obtaining such an effect, the diffusion prevention layer is preferably provided adjacent to the polarizing layer on the first stress relieving layer side of the polarizing layer, and the first stress relieving layer side of the polarizing layer and the retardation layer It is more preferable that the polarizing layer is provided on both sides, adjacent to the polarizing layer, or only via the alignment film forming the polarizing layer. When the anti-diffusion layer is provided on both the first stress relieving layer side and the retardation layer side of the polarizing layer, they may be the same or different.

The diffusion prevention layer is not particularly limited as long as it is a layer having a function of preventing diffusion of the dichroic dye. For example, a layer formed from a resin composition containing a water-soluble polymer, an active energy ray-curable resin and a layer formed from a curable composition containing.

Since the water-soluble polymer has a polarity significantly different from that of the dichroic dye, it can prevent the diffusion of the dichroic dye. Examples of water-soluble polymers that can form the diffusion barrier layer include polyacrylamide-based polymers; polyvinyl alcohol, ethylene-vinyl alcohol copolymers, (meth)acrylic acid or its anhydride-vinyl alcohol copolymers alcohol-based polymers; carboxyvinyl-based polymers; polyvinylpyrrolidone; starches; sodium alginate; These polymers may be used alone or in combination of two or more.

When the diffusion prevention layer is a layer formed from a resin composition containing a water-soluble polymer (hereinafter also referred to as a "water-soluble polymer-containing resin composition"), the content of the water-soluble polymer in the layer is preferably 75%. % by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more.

When the diffusion-preventing layer is a layer formed from a resin composition containing a water-soluble polymer, a cross-linked structure is formed by using a cross-linking agent to increase the denseness of the layer and improve the diffusion-preventing function of the dichroic dye. may be introduced. Such cross-linking agents include, for example, ionic cross-linking agents such as glyoxylate, water-soluble additives and cross-linking agents such as epoxy cross-linking agents, isocyanate cross-linking agents, glyoxal for the purpose of imparting water resistance. Hydrophobic cross-linking agents such as polyhydric aldehyde-based cross-linking agents such as glyoxal derivatives and metal compound-based cross-linking agents such as zirconium chloride-based or titanium lactate-based cross-linking agents may also be used.

When a cross-linking agent is used to introduce a cross-linked structure into the diffusion prevention layer, the amount to be added may be appropriately determined according to the type of cross-linking agent used. For example, it may be 0.1 to 100 parts by mass, preferably 1 to 50 parts by mass, and more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the water-soluble polymer. When the content of the cross-linking agent is within the above range, the anti-diffusion layer becomes dense, and the effect of shielding the dichroic dye in the light absorption anisotropic film is likely to be improved.

A water-soluble polymer-containing resin composition capable of forming a diffusion prevention layer is usually prepared as a solution in which a water-soluble polymer is dissolved in a solvent. The solvent may be selected according to the water-soluble polymer to be used, but typically includes water, alcohol, a mixture of water and alcohol, and the like, with water being preferred.

The solid content concentration of the water-soluble polymer-containing resin composition obtained by adding a solvent to the components constituting the diffusion prevention layer such as the water-soluble polymer and the cross-linking agent is preferably 1 to 50% by mass, more preferably 2 to 50% by mass. 30% by mass. When the solid content concentration of the water-soluble polymer-containing resin composition is within the above range, the viscosity of the composition is low, and therefore the coating property and handleability are improved.

The water-soluble polymer-containing resin composition may contain other components such as additives in addition to the water-soluble polymer, cross-linking agent and solvent such as water. Such other ingredients include, for example, preservatives, leveling agents, and the like. When the water-soluble polymer-containing resin composition contains other components such as additives, the amount thereof is preferably 10% by mass or less, more preferably 5% by mass or less, based on the solid content of the resin composition.

For example, the diffusion barrier layer can be obtained by coating the surface on which the diffusion barrier layer is to be formed with a resin composition containing a water-soluble polymer, and drying and curing the coating film.

The method of applying the water-soluble polymer-containing resin composition is not particularly limited, and the same known method as the method of applying the composition for forming a polarizing layer onto a substrate or the like can be used.

The drying temperature, time, and the like for forming the diffusion prevention layer from the coating film of the water-soluble polymer-containing resin composition are not particularly limited, and may be appropriately determined according to the composition of the water-soluble polymer-containing resin composition to be used. The drying treatment can be carried out, for example, by blowing hot air, and the temperature is usually in the range of 40-100°C, preferably 60-100°C. Also, the drying time is usually 10 to 600 seconds.

Since the active energy ray-curable resin can be highly polymerized, it tends to be excellent in the diffusion prevention function of the dichroic dye. A curable composition containing an active energy ray-curable resin capable of forming an antidiffusion layer (hereinafter also referred to as "a curable composition for forming an antidiffusion layer") includes a cation containing a cationically polymerizable compound as a curable compound. A polymerizable curable composition, a radically polymerizable curable composition containing a radically polymerizable compound as a curable compound, a hybrid curable composition containing both a cationic polymerizable compound and a radically polymerizable compound, and the like. be done. Specific examples of cationic polymerizable compounds include epoxy compounds having one or more epoxy groups in the molecule, oxetane compounds having one or more oxetane rings in the molecule, and vinyl compounds. Further, specific examples of radically polymerizable compounds include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, vinyl compounds, and the like. The diffusion prevention layer-forming curable composition can contain one or more cationic polymerizable compounds and/or can contain one or more radically polymerizable compounds.

The cationic polymerizable compound, which is the main component of the cationic polymerizable curable composition, is a compound that undergoes a cationic polymerization reaction and cures when irradiated with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, or by heating. It refers to oligomers, and examples thereof include epoxy compounds, oxetane compounds, and vinyl compounds. Among them, preferred cationic polymerizable compounds are epoxy compounds.

An epoxy compound is a compound having one or more, preferably two or more epoxy groups in the molecule. An epoxy compound may be used individually by 1 type, and may use 2 or more types together. Examples of epoxy compounds include alicyclic epoxy compounds, aromatic epoxy compounds, hydrogenated epoxy compounds, and aliphatic epoxy compounds. Among them, the epoxy compound preferably contains an alicyclic epoxy compound and an aliphatic epoxy compound from the viewpoint of weather resistance, curing speed and adhesiveness.

In one embodiment of the present invention, when the curable composition for forming a diffusion prevention layer contains an epoxy compound as a cationically polymerizable compound, the content of the epoxy compound is It is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, still more preferably 20 parts by mass or more, preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less.

When the total amount of curable compounds contained in the curable composition for forming a diffusion prevention layer (including the case of a hybrid type) containing a cationic polymerizable compound is 100% by mass, the content of the cationic polymerizable compound (2 or more When cationic polymerizable compounds are included, the total content thereof) is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more. In addition, the cationic polymerization type curable composition may further contain a polymer component (thermoplastic resin, etc.).

When the diffusion prevention layer-forming curable composition contains a cationic polymerizable compound, it preferably contains a photocationic polymerization initiator. Photocationic polymerization initiators generate cationic species or Lewis acids by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams, and initiate the polymerization reaction of cationic curable compounds. . Since the photocationic polymerization initiator acts catalytically with light, it is excellent in storage stability and workability even when mixed with a photocationically curable compound. Examples of compounds that generate cationic species or Lewis acids upon irradiation with active energy rays include onium salts such as aromatic iodonium salts and aromatic sulfonium salts, aromatic diazonium salts, and iron-arene complexes.

The photocationic polymerization initiator may be used alone or in combination of two or more. Among them, aromatic sulfonium salts are preferably used because they have ultraviolet absorption properties even in a wavelength region around 300 nm, so that they are excellent in curability and can give a cured product having good mechanical strength and adhesive strength.

The content of the photocationic polymerization initiator in the curable composition for forming the diffusion prevention layer is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass with respect to 100 parts by mass of the solid content of the curable compound. be. When the content of the cationic photopolymerization initiator is within the above range, the cationic polymerizable compound can be sufficiently cured, and high mechanical strength and adhesive strength can be imparted to the obtained diffusion prevention layer.

A hybrid type curable composition can be obtained by adding a radically polymerizable compound to the cationic polymerizable curable composition in addition to the cationically polymerizable compound. By using a radically polymerizable compound together, the effect of increasing the hardness and mechanical strength of the diffusion prevention layer can be expected, and the viscosity, curing speed, etc. of the curable composition can be more easily adjusted.

The radically polymerizable compound, which is the main component of the radically polymerizable curable composition, is a compound that undergoes a radical polymerization reaction and is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, or by heating. It refers to an oligomer, specifically a compound having an ethylenically unsaturated bond. Compounds having an ethylenically unsaturated bond include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, as well as styrene, styrenesulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl. vinyl compounds such as -2-pyrrolidone; Among them, preferred radically polymerizable compounds are (meth)acrylic compounds.

The (meth)acrylic compound is a compound having at least one (meth)acryloyloxy group in the molecule, and may be a monomer, oligomer or polymer. Examples of (meth)acrylic compounds include (meth)acrylate compounds such as monofunctional (meth)acrylate compounds and polyfunctional (meth)acrylate compounds; urethane (meth)acrylate compounds such as polyfunctional urethane (meth)acrylate compounds; Epoxy (meth)acrylate compounds such as polyfunctional epoxy (meth)acrylate compounds; carboxyl group-modified epoxy (meth)acrylate compounds, polyester (meth)acrylate compounds, and the like. The (meth)acrylic compounds may be used singly or in combination of two or more.

The (meth)acrylate compounds include monofunctional (meth)acrylate compounds having one (meth)acryloyloxy group in the molecule, and polyfunctional (meth)acrylate compounds having two or more (meth)acryloyloxy groups in the molecule. Acrylate compounds are mentioned.

When a polyfunctional (meth)acrylate compound is used, the crosslink density of the diffusion prevention layer can be adjusted by controlling the molecular weight between crosslink points and the number of crosslink points of the compound. More specifically, the smaller the molecular weight between cross-linking points, the higher the cross-linking density, and the higher the number of cross-linking points, the denser the cross-linking density, which can enhance the shielding property against the dichroic dye in the light absorption anisotropic film. .

A urethane (meth)acrylate compound generally means a reaction product of an isocyanate compound, a polyol compound and a (meth)acrylate compound, and is a polyfunctional urethane (meth)acrylate having two or more (meth)acryloyloxy groups in the molecule. A compound is preferred. Since the polyfunctional urethane (meth)acrylate compound can form a crosslinked structure, it is advantageous from the viewpoint of improving the dichroic dye diffusion prevention function of the diffusion prevention layer and can impart appropriate toughness. The number of functional groups of the polyfunctional urethane (meth)acrylate compound is preferably 2-5.

Examples of epoxy (meth)acrylate compounds include polyfunctional epoxy (meth)acrylate compounds that can be obtained by an addition reaction between polyglycidyl ether and (meth)acrylic acid and have at least two (meth)acryloyloxy groups in the molecule. ) acrylates and the like. Polyester (meth)acrylate compounds include, for example, compounds having an ester bond and at least two (meth)acryloyl groups (typically (meth)acryloyloxy groups) in the molecule.

In one embodiment of the present invention, when the diffusion prevention layer-forming curable composition contains a radically polymerizable compound, it preferably contains a polyfunctional (meth)acrylate compound as the radically polymerizable compound. In this case, the content of the polyfunctional (meth)acrylate compound is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and still more preferably 70 parts by mass with respect to 100 parts by mass of the solid content of the curable composition. or more, preferably 100 parts by mass or less, more preferably 95 parts by mass or less, and even more preferably 90 parts by mass or less.

In one embodiment of the present invention, when the diffusion barrier layer-forming curable composition contains a radically polymerizable compound, a polyfunctional (meth)acrylate compound and a polyfunctional urethane (meth)acrylate compound are used as the radically polymerizable compound. preferably included. In this case, the ratio of the polyfunctional (meth)acrylate compound and the urethane (meth)acrylate compound is preferably 95:5 to 50:50, more preferably 90:10 to 70:30 (polyfunctional (meth)acrylate compound : urethane (meth)acrylate compound, mass ratio).

When the diffusion prevention layer-forming curable composition contains a radically polymerizable compound, it preferably contains a radical photopolymerization initiator. A photo-radical polymerization initiator initiates a polymerization reaction of a radical-curable compound by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams. A photoradical polymerization initiator may be used individually by 1 type, and may use 2 or more types together.

Specific examples of photoradical polymerization initiators include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1- Acetophenone initiators such as [4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone and 4, Benzophenone initiators such as 4′-diaminobenzophenone; alkylphenone initiators such as 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone; benzoin propyl ether and benzoin ether-based initiators such as benzoin ethyl ether; thioxanthone-based initiators such as 4-isopropylthioxanthone; acylphosphine oxide-based initiators such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like.

The content of the photoradical polymerization initiator in the diffusion prevention layer-forming curable composition is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, based on 100 parts by mass of the solid content of the curable compound. be. When the content of the photoradical polymerization initiator is within the above range, the photoradical polymerization initiator is less likely to remain while sufficiently expressing the polymerization initiation ability and improving the curability, resulting in a decrease in visible light transmittance. etc., can be easily suppressed.

In the present invention, the curable composition for forming a diffusion barrier layer may contain an organic solvent in order to adjust the viscosity to be suitable for the coating method to be employed, for example, and may contain substantially no solvent (no solvent). In addition, "substantially free" means not excluding the case where the solvent is unavoidably mixed.

Any solvent can be used as long as it can dissolve the components constituting the anti-diffusion layer. These solvents may be used alone or in combination of two or more.

The type and content of the solvent are appropriately selected according to the type, content, shape, coating method, thickness of the diffusion prevention layer, and the like of the components constituting the diffusion prevention layer. When a solvent is included, the amount thereof is, for example, preferably 3 to 1000 parts by mass, more preferably 5 to 100 parts by mass, more preferably 7 to 50 parts by mass, relative to 100 parts by mass of the solid content of the curable composition. is.

The curable composition for forming a diffusion prevention layer may optionally contain a cationic polymerization accelerator, a photosensitizer, an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow Additives such as modifiers, plasticizers, antifoaming agents, antistatic agents and leveling agents may be contained.

For example, a curable composition for forming a diffusion barrier layer is applied to the surface on which the diffusion barrier layer is to be formed, and the coating film is irradiated with active energy rays to cure the composition to obtain a diffusion barrier layer. can be done. The method of applying the curable composition for forming the diffusion prevention layer, the type of active energy ray used for curing, the light source, the irradiation conditions, etc. are the same as the method of applying and curing the composition for forming the polarizing layer. Conditions and the like can be adopted.

The thickness of the diffusion prevention layer is preferably 0.1 μm or more and 5 μm or less, more preferably 0.3 μm or more and 4 μm or less, and still more preferably 0.5 μm or more and 3 μm or less. Within the above range, the diffusion of the dichroic dye in the polarizing layer to other layers can be effectively suppressed. When the diffusion prevention layer is included on both the first stress relaxation layer side and the retardation layer side of the polarizing layer, the thicknesses thereof may be the same or different.

[Retardation layer]
The retardation layer contained in the optical layered body of the present invention is a layer exhibiting a retardation. From the viewpoint of thinning the optical laminate, the retardation layer is preferably a coating layer, more preferably a cured layer of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound. The optical laminate of the present invention suppresses the occurrence of lamination misalignment, wrinkles, etc. when the two outer layer surfaces appearing by peeling the first base film and the second base film are respectively transferred and assembled into a display device. Since it is excellent in the effect of polarizing, it can be expected to have a high circular polarization function even after it is incorporated in a display device or the like by double-sided transfer. The optical laminate of the present invention may contain one or more retardation layers.

The optical layered body of the present invention preferably contains a retardation layer that satisfies the following formula (3).
120 nm≦Re(550)≦170 nm (3)
[In the formula, Re(λ) represents an in-plane retardation value of the retardation layer at a wavelength of λnm. ]
When the in-plane retardation Re (550) of the retardation layer is within the range of formula (3), the retardation layer becomes a retardation layer functioning as a quarter-wave plate, and an optical laminate including the retardation layer When the body (circularly polarizing plate) is applied to an organic EL display device or the like, the effect of improving the front reflection hue (the effect of suppressing coloration) tends to increase. A more preferable range of the in-plane retardation value is 130 nm≦Re(550)≦150 nm.

Moreover, it is preferable that the retardation layer satisfying the formula (3) satisfies the following formulas (4) and (5).
Re(450)/Re(550)≤1.00 (4)
1.00≦Re(650)/Re(550) (5)
[In the formula, Re(λ) represents an in-plane retardation value of the retardation layer at a wavelength of λnm. ]
When the retardation layer satisfies the formulas (4) and (5), the retardation layer has an in-plane retardation value at a short wavelength smaller than an in-plane retardation value at a long wavelength, that is, a so-called reverse wavelength dispersion. show gender. An optical layered body (circularly polarizing plate) having such a retardation layer tends to be excellent in front hue when incorporated in an organic EL display device or the like. Re(450)/Re(550) is preferably 0.70 or more, more preferably 0.78 or more, from the viewpoint of improving the reverse wavelength dispersion and further enhancing the effect of improving the reflection hue in the front direction. Also, it is preferably 0.92 or less, more preferably 0.90 or less, still more preferably 0.87 or less, particularly preferably 0.86 or less, and most preferably 0.85 or less. Also, Re(650)/Re(550) is preferably 1.01 or more, more preferably 1.02 or more.

The in-plane retardation value can be adjusted by the film thickness d of the retardation layer. Since the in-plane retardation value is determined by the above formula Re (λ) = (nx (λ) - ny (λ)) × d, the desired in-plane retardation value (Re (λ): wavelength λ ( In order to obtain the in-plane retardation value of the retardation layer in nm), the three-dimensional refractive index and the film thickness d should be adjusted. In the above formula, d represents the thickness of the target retardation layer, and nx is the principal refraction at the wavelength λ nm in the direction parallel to the plane of the retardation layer in the refractive index ellipsoid formed by the retardation layer. and ny is the refractive index at a wavelength λnm in a direction parallel to the plane of the retardation layer and perpendicular to the nx direction in the refractive index ellipsoid formed by the retardation layer. show.

The optical laminate of the present invention preferably includes a retardation layer composed of a "horizontally aligned liquid crystal cured layer" in which a polymerizable liquid crystal compound is cured in a state in which it is aligned horizontally with respect to the plane of the substrate, and the above formula ( It is more preferable to include a horizontally aligned liquid crystal cured layer that satisfies 3) to (5). When the optical laminate of the present invention includes one retardation layer, the retardation layer constituting the retardation layer is usually a "horizontally aligned liquid crystal cured layer".

The optical laminate of the present invention may further include a retardation layer that is a liquid crystal cured layer (retardation layer) that is a positive C plate in addition to the retardation layer that is a horizontally aligned liquid crystal cured layer. The cured liquid crystal layer, which is a positive C plate, is a "vertically aligned liquid crystal cured layer" in which a polymerizable liquid crystal compound is cured in a state of being vertically aligned with respect to the substrate surface. By including a combination of a retardation layer that is a horizontally aligned liquid crystal cured layer and a retardation layer that is a vertically aligned liquid crystal cured layer, the front reflection hue can be improved when the optical laminate is applied to an organic EL display device or the like. In addition, an improvement in oblique reflection hue can also be expected. When the optical laminate of the present invention includes a vertically aligned liquid crystal cured layer, the retardation layer, which is the vertically aligned liquid crystal cured layer, is preferably arranged between the polarizing layer and the second stress relaxation layer.

When the optical laminate of the present invention includes a vertically aligned liquid crystal cured layer, the liquid crystal cured layer preferably satisfies formula (6).
−100 nm≦Rth(550)≦−40 nm (6)
[In the formula, Rth (550) represents the retardation value in the thickness direction at a wavelength of 550 nm of the liquid crystal cured layer, and is Rth = ((nx (λ) + ny (λ)) / 2-nz) × d (d is represents the thickness of the liquid crystal cured layer, nx represents the principal refractive index at the wavelength λnm in the direction parallel to the plane of the liquid crystal cured layer in the refractive index ellipsoid formed by the liquid crystal cured layer, and ny represents the liquid crystal cured layer formed In the refractive index ellipsoid, it is parallel to the plane of the liquid crystal cured layer and represents the refractive index at the wavelength λnm in the direction orthogonal to the direction of the nx, and nz is the refractive index formed by the liquid crystal cured layer In the index ellipsoid, it represents the refractive index at a wavelength λnm in the direction perpendicular to the plane of the liquid crystal cured layer). ]

When the vertically aligned liquid crystal cured layer satisfies the formula (6), the oblique reflection hue can be improved when the optical laminate (circularly polarizing plate) including the liquid crystal cured layer is applied to an organic EL display device. The retardation value Rth(550) in the thickness direction of the liquid crystal cured layer is more preferably −90 nm or more, more preferably −80 nm or more, and more preferably −50 nm or less.

In the present invention, the retardation layer (horizontal alignment liquid crystal cured layer and vertical alignment liquid crystal cured layer) is a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound (hereinafter, also referred to as a "composition for forming a retardation layer"). ) consists of a hardened layer. The polymerizable liquid crystal compound can be appropriately selected from conventionally known polymerizable liquid crystal compounds in the field of retardation films according to desired optical properties.

A polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. As the polymerizable liquid crystal compound, in general, a polymer (cured product) obtained by polymerizing the polymerizable liquid crystal compound alone in a state aligned in a specific direction is opposite to the polymerizable liquid crystal compound exhibiting positive wavelength dispersion. and a polymerizable liquid crystal compound exhibiting wavelength dispersion. In the present invention, either one type of polymerizable liquid crystal compound may be used alone, or both types of polymerizable liquid crystal compounds may be mixed and used. Moreover, when the optical laminate includes a horizontally aligned liquid crystal cured layer and a vertically aligned liquid crystal cured layer, the polymerizable liquid crystal compounds constituting these layers may be the same or different. From the viewpoint of easily improving the optical properties of the optical laminate, in one embodiment of the present invention, the horizontally aligned liquid crystal cured layer is a cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting so-called reverse wavelength dispersion. is preferably

The polymerizable group possessed by the polymerizable liquid crystal compound forming the retardation layer in the present invention is preferably a photopolymerizable group. A photopolymerizable group is a polymerizable group, and refers to a group that can participate in a polymerization reaction by a reactive species generated from a photopolymerization initiator, such as an active radical or an acid. Examples of photopolymerizable groups include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, (meth)acryloyl group, oxiranyl group and oxetanyl group. Among them, a (meth)acryloyl group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyl group is more preferred.

The liquid crystallinity exhibited by the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferable because it enables precise film thickness control. Further, the phase-ordered structure of the thermotropic liquid crystal may be nematic liquid crystal, smectic liquid crystal, or discotic liquid crystal. A polymerizable liquid crystal compound can be used individually or in combination of 2 or more types.

A polymerizable liquid crystal compound having a so-called T-shaped or H-shaped molecular structure tends to exhibit reverse wavelength dispersion when polymerized and cured, and a polymerizable liquid crystal compound having a T-shaped molecular structure exhibits stronger properties. It tends to exhibit reverse wavelength dispersion.

The polymerizable liquid crystal compound exhibiting reverse wavelength dispersion is preferably a compound having the following characteristics (A) to (D).
(A) A compound capable of forming a nematic phase or a smectic phase.
(B) The polymerizable liquid crystal compound has π electrons along the longitudinal direction (a).
(C) It has π electrons in a direction crossing the major axis direction (a) [intersecting direction (b)].
(D) A polymerizable liquid crystal compound defined by the following formula (i), where N(πa) is the total number of π electrons present in the longitudinal direction (a), and N(Aa) is the total molecular weight present in the longitudinal direction. π electron density in the long axis direction (a) of
D(πa)=N(πa)/N(Aa) (i)
and a polymerizable liquid crystal compound defined by the following formula (ii), where N(πb) is the sum of π electrons present in the cross direction (b), and N(Ab) is the sum of the molecular weights present in the cross direction (b). π electron density in the cross direction (b) of
D(πb)=N(πb)/N(Ab) (ii)
is the formula (iii)
0≦[D(πa)/D(πb)]<1 (iii)
[that is, the π electron density in the cross direction (b) is higher than the π electron density in the long axis direction (a)]. As described above, a polymerizable liquid crystal compound having π electrons on the major axis and the direction crossing it generally tends to form a T-shaped structure.

In the features (A) to (D) above, the major axis direction (a) and the number of π electrons N are defined as follows.
- The long axis direction (a) is, for example, the long axis direction of a rod-like structure in the case of a compound having a rod-like structure.
- The number of π electrons N (πa) present in the major axis direction (a) does not include π electrons that disappear due to the polymerization reaction.
The number of π electrons N (πa) present along the major axis direction (a) is the total number of π electrons on the major axis and the π electrons conjugated therewith, for example, present along the major axis direction (a) It includes the number of π electrons present in a ring that satisfies Hückel's rule.
- The number of π electrons N (πb) existing in the cross direction (b) does not include π electrons that disappear due to the polymerization reaction.
A polymerizable liquid crystal compound satisfying the above has a mesogenic structure in the major axis direction. This mesogenic structure develops a liquid crystal phase (nematic phase, smectic phase, etc.).

A nematic phase or a smectic phase can be formed by heating a polymerizable liquid crystal compound satisfying the above (A) to (D) above the phase transition temperature. In the nematic phase or smectic phase formed by aligning the polymerizable liquid crystal compound, the major axis directions of the polymerizable liquid crystal compound are usually oriented parallel to each other, and the major axis directions are the nematic phase or the smectic phase. orientation direction. When such a polymerizable liquid crystal compound is made into a film and polymerized in a nematic phase or smectic phase, a polymer film composed of a polymer oriented in the major axis direction (a) can be formed. . This polymer film absorbs ultraviolet rays by π electrons in the long axis direction (a) and π electrons in the cross direction (b). Let λbmax be the absorption maximum wavelength of ultraviolet rays absorbed by π electrons in the cross direction (b). λbmax is typically between 300 nm and 400 nm. The density of π electrons satisfies the above formula (iii), and the π electron density in the cross direction (b) is higher than the π electron density in the major axis direction (a). is greater than the absorption of linearly polarized UV light (wavelength: λbmax) having a vibration plane in the major axis direction (a). The ratio (absorbance in cross direction (b) of linearly polarized ultraviolet rays/absorbance in long axis direction (a)) is, for example, more than 1.0, preferably 1.2 or more, usually 30 or less, for example 10 or less. is.

Generally, the polymerizable liquid crystal compound having the above characteristics often exhibits reverse wavelength dispersion in the birefringence of the polymer when polymerized in a unidirectionally oriented state. Specifically, for example, a compound represented by the following formula (X) (hereinafter also referred to as “polymerizable liquid crystal compound (X)”) can be used.

In formula (X), Ar represents a divalent group having an optionally substituted aromatic group. Examples of the aromatic group here include groups exemplified by (Ar-1) to (Ar-23) described later. Ar may also have two or more aromatic groups. At least one or more of a nitrogen atom, an oxygen atom and a sulfur atom may be contained in the aromatic group. When the number of aromatic groups contained in Ar is two or more, the two or more aromatic groups may be bonded to each other with a single bond, -CO-O-, or a divalent linking group such as -O-. .

In formula (X), G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, a carbon may be substituted with an alkoxy group, a cyano group or a nitro group having a number of 1 to 4, and the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group are an oxygen atom or a sulfur atom; Alternatively, it may be substituted with a nitrogen atom.

In formula (X), L ¹ , L ² , B ¹ and B ² are each independently a single bond or a divalent linking group.

In formula (X), k and l each independently represent an integer of 0 to 3 and satisfy the relationship 1≦k+l. Here, when 2≦k+l, B ¹ and B ² and G ¹ and G ² may be the same or different from each other.

In formula (X), E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms. A hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH ₂ - contained in the alkanediyl group is -O-, -S-, -C(=O)- may be substituted with

In formula (X), P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, at least one of which is a polymerizable group.

G ¹ and G ² are each independently preferably a 1,4-phenylenediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms. , a 1,4-cyclohexanediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1 substituted with a methyl group ,4-phenylenediyl group, unsubstituted 1,4-phenylenediyl group or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group or unsubstituted It is a substituted 1,4-trans-cyclohexanediyl group.
At least one of G ¹ and G ² present in plurality is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² is more preferably a divalent alicyclic hydrocarbon group.

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

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

k and l are preferably in the range of 2≦k+l≦6, preferably k+l=4, more preferably k=2 and l=2, from the viewpoint of exhibiting reverse wavelength dispersion. It is preferable that k=2 and l=2 because of the symmetrical structure.

Polymerizable groups represented by P ¹ or P ² include epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, (meth)acryloyl group, oxiranyl group, and oxetanyl group and the like. Among them, a (meth)acryloyl group, a vinyl group and a vinyloxy group are preferred, and a (meth)acryloyl group is more preferred.

Ar preferably has at least one selected from an optionally substituted aromatic hydrocarbon ring, an optionally substituted aromatic heterocycle, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include benzene ring, naphthalene ring, anthracene ring and the like, with benzene ring and naphthalene ring being preferred. Examples of the aromatic heterocyclic ring include furan ring, benzofuran ring, pyrrole ring, indole ring, thiophene ring, benzothiophene ring, pyridine ring, pyrazine ring, pyrimidine ring, triazole ring, triazine ring, pyrroline ring, imidazole ring, and pyrazole ring. , thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. Among them, it preferably has a thiazole ring, a benzothiazole ring, or a benzofuran ring, and more preferably has a benzothiazole ring. Moreover, when a nitrogen atom is contained in Ar, the nitrogen atom preferably has a π electron.

In formula (X), the total number N _π of π electrons possessed by the group represented by Ar is usually 6 or more, preferably 8 or more, more preferably 10 or more, and still more preferably 14 or more, Especially preferably, it is 16 or more. Also, it is preferably 36 or less, more preferably 32 or less, even more preferably 26 or less, and particularly preferably 24 or less.

Examples of aromatic groups contained in Ar include the following groups.

In formulas (Ar-1) to (Ar-23), the * mark represents a connecting portion, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, or an alkyl having 1 to 12 carbon atoms. a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, alkylthio group having 1 to 12 carbon atoms, N-alkylamino group having 1 to 12 carbon atoms, N,N-dialkylamino group having 2 to 12 carbon atoms, N-alkylsulfamoyl group having 1 to 12 carbon atoms or carbon represents an N,N-dialkylsulfamoyl group of numbers 2 to 12; Moreover, Z ⁰ , Z ¹ and Z ² may contain a polymerizable group.

In formulas (Ar-1) to (Ar-23), Q ¹ and Q ² are each independently -CR ^2' R ^3' -, -S-, -NH-, -NR ^2' -, - represents CO— or —O—, and R ^2′ and R ^3′ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms;

In formulas (Ar-1) to (Ar-23), J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.

In formulas (Ar-1) to (Ar-23), Y ¹ , Y ² and Y ³ each independently represent an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

In formulas (Ar-1) to (Ar-23), W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0-6.

Examples of the aromatic hydrocarbon group for Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group and biphenyl group. , is preferably a naphthyl group, more preferably a phenyl group. Examples of aromatic heterocyclic groups include those having 4 to 20 carbon atoms containing at least one heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group. Examples include aromatic heterocyclic groups, and preferred are furyl, thienyl, pyridinyl, thiazolyl, and benzothiazolyl groups.

Y ¹ , Y ² and Y ³ may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. A polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. A polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

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

Q ¹ and Q ² are preferably -NH-, -S-, -NR ^2' - and -O-, and R ^2' is preferably a hydrogen atom. Among them, -S-, -O- and -NH- are particularly preferred.

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

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

The compound represented by formula (X) can be produced, for example, according to the method described in JP-A-2010-31223.

As the polymerizable liquid crystal compound forming the retardation layer in the present invention, for example, a compound containing a group represented by the following formula (Y) (hereinafter also referred to as "polymerizable liquid crystal compound (Y)") may be used. . The polymerizable liquid crystal compound (Y) generally tends to exhibit positive wavelength dispersion. These polymerizable liquid crystal compounds can be used alone or in combination of two or more.

P11-B11-E11-B12-A11-B13- (Y)
[In formula (Y), P11 represents a polymerizable group.
A11 represents a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group.
B11 is -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -CO-NR ¹⁶ -, -NR ¹⁶ -CO-, -CO-, - represents CS- or a single bond. R ¹⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
B12 and B13 each independently represent -C≡C-, -CH=CH-, -CH ₂ -CH ₂ -, -O-, -S-, -C(=O)-, -C(=O ) -O-, -O-C(=O)-, -O-C(=O)-O-, -CH=N-, -N=CH-, -N=N-, -C(=O ) -NR ¹⁶ -, -NR ¹⁶ -C(=O)-, -OCH ₂ -, -OCF ₂ -, -CH ₂ O-, -CF ₂ O-, -CH=CH-C(=O)- represents O-, -OC(=O)-CH=CH-, -H, -C≡N or a single bond;
E11 represents an alkanediyl group having 1 to 12 carbon atoms, the hydrogen atom contained in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, and the hydrogen atom contained in the alkoxy group may be substituted with a halogen atom. -CH ₂ - constituting the alkanediyl group may be replaced with -O- or -CO-. ]

The number of carbon atoms in the aromatic hydrocarbon group and alicyclic hydrocarbon group of A11 is preferably in the range of 3 to 18, more preferably in the range of 5 to 12, particularly 5 or 6. preferable. A hydrogen atom contained in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group represented by A11 is a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, It may be substituted with a cyano group or a nitro group, and hydrogen atoms contained in the C1-6 alkyl group and the C1-6 alkoxy group may be substituted with a fluorine atom. A11 is preferably a cyclohexane-1,4-diyl group or a 1,4-phenylene group.

E11 is preferably a linear alkanediyl group having 1 to 12 carbon atoms. —CH ₂ — constituting the alkanediyl group may be replaced with —O—.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane -1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group and dodecane-1,12- Linear alkanediyl groups having 1 to 12 carbon atoms such as diyl groups; -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -, -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -O- CH ₂ -CH ₂ - and -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ - and the like.
B11 is preferably -O-, -S-, -CO-O- or -O-CO-, and more preferably -CO-O-.
B12 and B13 each independently represent -O-, -S-, -C(=O)-, -C(=O)-O-, -OC(=O)-, -OC (=O)-O- is preferred, and -O- or -OC(=O)-O- is more preferred.

［式（Ｐ－１１）～（Ｐ－１５）中、
Ｒ^１７～Ｒ^２１はそれぞれ独立に、炭素数１～６のアルキル基または水素原子を表わす。］ As the polymerizable group represented by P11, a radically polymerizable group or a cationic polymerizable group is preferable in terms of high polymerization reactivity, particularly photopolymerization reactivity, and handling is easy, and the production of the liquid crystal compound itself is also easy. Therefore, the polymerizable group is preferably a group represented by the following formulas (P-11) to (P-15).

[In the formulas (P-11) to (P-15),
R ¹⁷ to R ²¹ each independently represent an alkyl group having 1 to 6 carbon atoms or a hydrogen atom. ]

Specific examples of the groups represented by formulas (P-11) to (P-15) include groups represented by the following formulas (P-16) to (P-20).

P11 is preferably a group represented by formulas (P-14) to (P-20), more preferably a vinyl group, a p-stilbene group, an epoxy group or an oxetanyl group.
More preferably, the group represented by P11-B11- is an acryloyloxy group or a methacryloyloxy group.

Examples of the polymerizable liquid crystal compound (Y) include compounds represented by formula (I), formula (II), formula (III), formula (IV), formula (V) or formula (VI).
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-B16-E12-B17-P12 (I)
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-F11 (II)
P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-E12-B17-P12 (III)
P11-B11-E11-B12-A11-B13-A12-B14-A13-F11 (IV)
P11-B11-E11-B12-A11-B13-A12-B14-E12-B17-P12 (V)
P11-B11-E11-B12-A11-B13-A12-F11 (VI)
[In the formula,
A11, B11-B13 and P11 are as defined above;
A12-A14 are each independently synonymous with A11, B14-B16 are each independently synonymous with B12, B17 is synonymous with B11, E12 is synonymous with E11, P12 is synonymous with P11 be.
F11 is a hydrogen atom, an alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, a dimethylamino group, a hydroxyl group, a methylol group, a formyl group, a sulfo group; (—SO ₃ H), a carboxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms or a halogen atom, and —CH ₂ — constituting the alkyl group and the alkoxy group may be replaced with —O— good. ]

Specific examples of the polymerizable liquid crystal compound (Y) are described in "3.8.6 Network (completely crosslinked type)" in Liquid Crystal Handbook (Liquid Crystal Handbook Editing Committee, published by Maruzen Co., Ltd. on October 30, 2000). , Compounds having a polymerizable group among the compounds described in "6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material", JP 2010-31223, JP 2010-270108, JP Polymerizable liquid crystals described in JP-A-2011-6360 and JP-A-2011-207765 can be mentioned.

Both the polymerizable liquid crystal compound (X) and the polymerizable liquid crystal compound (Y) can be horizontally aligned or vertically aligned. Moreover, the polymerizable liquid crystal compound (X) and the polymerizable liquid crystal compound (Y) may be used alone, or two or more of them may be used, or both may be used in combination.

The content of the polymerizable liquid crystal compound in the retardation layer-forming composition is, for example, 70 to 99.5 parts by mass, preferably 80 to 99.5 parts by mass, with respect to 100 parts by mass of the solid content of the retardation layer-forming composition. 99 parts by mass, preferably 85 to 98 parts by mass, and even more preferably 90 to 95 parts by mass. If the content of the polymerizable liquid crystal compound is within the above range, it is advantageous from the viewpoint of the orientation of the obtained retardation layer. When the retardation layer-forming composition contains two or more polymerizable liquid crystal compounds, the total amount of all the liquid crystal compounds contained in the retardation layer-forming composition is preferably within the above content range. .

The retardation layer-forming composition may contain a polymerization initiator for initiating the polymerization reaction of the polymerizable liquid crystal compound. The polymerization initiator can be appropriately selected from those conventionally used in the field, and may be a thermal polymerization initiator or a photopolymerization initiator. A photopolymerization initiator is preferable because it can initiate a polymerization reaction. Suitable photopolymerization initiators that can be used in the polarizing layer-forming composition are the same as those exemplified above.

Since the composition for forming a retardation layer is usually applied to a substrate film or the like in a state of being dissolved in a solvent, it preferably contains a solvent. As the solvent, a solvent capable of dissolving the polymerizable liquid crystal compound is preferable, and a solvent inert to the polymerization reaction of the polymerizable liquid crystal compound is preferable. Examples of the solvent include those exemplified above as usable in the polarizing layer-forming composition.

In addition, the retardation layer-forming composition may contain the photosensitizer, the leveling agent, and the additives exemplified as the additives contained in the polarizing layer-forming composition, if necessary. Examples of the photosensitizer and leveling agent include those exemplified above as usable in the polarizing layer-forming composition.

The retardation layer-forming composition can be prepared, for example, by mixing and stirring a polymerizable liquid crystal compound and, if necessary, a polymerization initiator, a solvent, additives, and the like.

The retardation layer is formed, for example, by coating a retardation layer-forming composition on a substrate or an alignment film, drying the obtained coating film, and removing the polymerizable liquid crystal compound in the retardation layer-forming composition. After orienting the polymerizable liquid crystal compound, the polymerizable liquid crystal compound is polymerized by light irradiation or the like while maintaining the orientation state. Examples of the substrate include the same substrate films as those constituting the optical layered body of the present invention. As the alignment film, in addition to the photo-alignment film exemplified above as a film that can be used in producing the polarizing layer of the present invention, an alignment film containing an alignment polymer, and a groove alignment film having an uneven pattern or a plurality of grooves on the surface. A film or the like may be mentioned, and an appropriate selection may be made according to the desired alignment control force and the like.

Examples of the oriented polymer include polyamides and gelatins having an amide bond in the molecule, polyimide having an imide bond in the molecule and its hydrolysates such as polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, poly Oxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylic acid esters. Among them, polyvinyl alcohol is preferred. Orientation polymer can be used individually or in combination of 2 or more types.

An alignment film containing an alignment polymer is usually formed by applying a composition in which an alignment polymer is dissolved in a solvent (hereinafter also referred to as an "alignment polymer composition") to the surface of a substrate film or the like on which an alignment film is to be formed. , the solvent is removed, or the oriented polymer composition is applied to the substrate, the solvent is removed, and rubbing is performed (rubbing method). Examples of the solvent include the same solvents as those previously exemplified as the solvent that can be used in the polarizing layer-forming composition.

The concentration of the oriented polymer in the oriented polymer composition may be within a range in which the oriented polymer material can be completely dissolved in the solvent. 0.1 to 10% is more preferable.

A commercially available alignment film material may be used as it is as the alignment polymer composition. Commercially available alignment film materials include Sanever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optomer (registered trademark, manufactured by JSR Corporation).

The method of applying the oriented polymer composition to the surface of the substrate or the like on which the orientation film is to be formed and the method of removing the solvent in the coating film include the method of applying the polarizing layer-forming composition to the substrate film or the like, and the method of removing the solvent in the coating film. A method similar to the method for removing the solvent in the coating film can be employed.

A rubbed alignment film is obtained by subjecting the dried coating film of the resulting alignment polymer composition to a rubbing treatment. Examples of the rubbing treatment include a method in which a rubbing roll wound with a rubbing cloth and rotating is brought into contact with a dry coating film of the oriented polymer composition. A plurality of regions (patterns) with different alignment directions can be formed in the alignment film by masking during the rubbing process.

A groove alignment film is a film having an uneven pattern or a plurality of grooves on its surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at regular intervals, liquid crystal molecules are aligned along the grooves.

As a method for obtaining a grooved alignment film, after exposure through an exposure mask having patterned slits on the surface of a photosensitive polyimide film, development and rinsing are performed to form an uneven pattern, and a plate having grooves on the surface. A method of forming a pre-cured UV curable resin layer on a shaped master, transferring the formed resin layer to a substrate or the like and then curing it, and a pre-curing pre-cured resin layer formed on the surface on which the alignment film is to be formed. For example, a roll-shaped master plate having a plurality of grooves is pressed against a UV curable resin film to form unevenness, and then cured.

The thickness of the alignment film (orientation film or photo-alignment film containing an alignment polymer) for forming the retardation layer is usually in the range of 10 to 10000 nm, preferably in the range of 10 to 2500 nm, more preferably 10 1000 nm or less, more preferably 10 to 500 nm, particularly preferably 50 to 250 nm.

In the optical layered body of the present invention, the thickness of the retardation layer can be appropriately selected according to the display device to which it is applied. More preferably, it is 1 to 3 μm. When the optical layered body of the present invention includes a plurality of retardation layers, the thickness of each retardation layer included in the retardation layer may be the same or different, but each should be within the above range. preferable.

When the optical laminate of the present invention includes a retardation layer composed of a horizontally aligned liquid crystal cured layer and a retardation layer composed of a vertically aligned liquid crystal cured layer, the vertically aligned liquid crystal cured layer is between the polarizing layer and the second stress relaxation layer. is preferably placed in the When a retardation layer made of a horizontally aligned liquid crystal cured layer and a retardation layer made of a vertically aligned liquid crystal cured layer are included, a polarizing layer, an adhesive layer, a first retardation layer, a second retardation layer and a second It is preferable that the layers are laminated in the order of the stress relaxation layers. In this case, either the retardation layer that is the horizontally aligned liquid crystal cured layer or the retardation layer that is the vertically aligned liquid crystal cured layer may be arranged on the polarizing layer side (that is, the first retardation layer). The retardation layer composed of the horizontally aligned liquid crystal cured layer and the retardation layer composed of the vertically aligned liquid crystal cured layer may be bonded via an adhesive layer, or a vertically aligned liquid crystal cured layer may be provided with a vertical alignment regulation layer. A vertically aligned liquid crystal cured layer is laminated with or without an alignment film having a force, or a horizontal alignment layer is laminated on a vertically aligned liquid crystal cured layer with or without an alignment film having a horizontal alignment regulating force. An oriented liquid crystal cured layer may be laminated.

[Adhesive layer]
In the present invention, the adhesive layer arranged between the polarizing layer and the retardation layer is a layer formed from an adhesive. The tacky-adhesive layer can be formed from a known tacky-adhesive agent as long as it can function as a layer for bonding the polarizing layer and the retardation layer. The pressure-sensitive adhesive or adhesive is not particularly limited, and conventionally known pressure-sensitive adhesives and adhesives can be used without particular limitations. Examples of adhesives include adhesives having a base polymer such as acrylic, rubber, urethane, silicone, and polyvinyl ether. Alternatively, an energy ray-curable adhesive, a heat-curable adhesive, or the like may be used. Examples of adhesives include active energy ray-curable adhesives, water-based adhesives, organic solvent-based adhesives, and non-solvent-based adhesives. In one embodiment of the invention, the adhesive layer is formed from an adhesive.

The thickness of the adhesive layer is usually 1-40 μm, preferably 3-25 μm.

When the polarizing layer and the retardation layer are laminated, it is preferable to laminate such that the slow axis (optical axis) of the retardation layer and the absorption axis of the polarizing layer are substantially at 45°. By laminating such that the slow axis (optical axis) of the retardation layer and the absorption axis of the polarizing layer are substantially at 45°, a function as a circularly polarizing plate can be obtained. Incidentally, substantially 45° is usually in the range of 45±5°.

[Optical laminate]
The optical laminate of the present invention comprises a first substrate film, a first stress relaxation layer, a polarizing layer, an adhesive layer, a retardation layer, and a second stress relaxation layer so as to have a desired structure according to its use. , and the second base film, and if necessary, the alignment film, the diffusion prevention layer, etc. can be produced by forming and laminating them in an appropriate order according to the production method described above for each layer.
For example, when the optical laminate of the present invention has an anti-diffusion layer, it can be produced by the following procedure: forming an alignment film on the anti-diffusion layer formed on the substrate film; After forming a polarizing layer on the polarizing layer, a diffusion preventing layer is further formed on the polarizing layer to produce a laminate in which the polarizing layer is provided between the two diffusion preventing layers; A laminate having a retardation layer is produced by forming a retardation layer through an alignment film, and the laminate having the retardation layer and the laminate having the polarizing layer are adhered with an adhesive. Thus, a laminate (A) containing substrate film/diffusion prevention layer/alignment film/polarizing layer/diffusion prevention layer/adhesive layer/retardation layer/alignment film/substrate film in this order is produced; Furthermore, a first stress relaxation layer is formed on the first base film, a laminate (B) consisting of the first base film / first stress relaxation layer / base film, and a second base film on the second base film 2 forming a stress relieving layer to produce a laminate (C) consisting of a second base film/second stress relieving layer/base film; the base film of the laminate (A) and the laminate (B) The base film is peeled off, the diffusion prevention layer and the first stress relaxation layer are bonded, the base films of both outer layers of the laminate (A), the base film of the laminate (B) and the laminate By respectively peeling the base film of (C) and bonding the diffusion prevention layer and the first stress relaxation layer and the retardation layer and the second stress relaxation layer respectively, the first base film / first stress An optical laminate comprising relaxation layer/diffusion prevention layer/orientation film/polarizing layer/diffusion prevention layer/adhesive layer/retardation layer/orientation film/second stress relaxation layer/second substrate film in this order is obtained. be done.

In the optical laminate of the present invention, the total thickness of the layers located between the first stress relaxation layer and the second stress relaxation layer is 20 μm or less. The present invention has a structure suitable for suppressing the occurrence of lamination misalignment and wrinkles that tend to occur during transfer in a thin optical laminate, and is arranged between the first stress relaxation layer and the second stress relaxation layer. In a laminated body having a thin structure (laminated body) for providing a circularly polarized light function consisting of a polarizing layer, a retardation layer, and the like, a more remarkable effect of the present invention is likely to be obtained. In the present invention, the total thickness of the layers positioned between the first stress relieving layer and the second stress relieving layer is preferably 18 μm or less, more preferably 16 μm or less, although it varies depending on the desired layer structure. Although the lower limit of the total thickness of the layers located between the first stress relaxation layer and the second stress relaxation layer is not particularly limited, it is usually 5 μm or more.

In one embodiment of the present invention, the thickness (T1) of the layered body (hereinafter also referred to as "laminate a") consisting of the layers from the first base film to the first stress relaxation layer, and the first stress relaxation layer The film thickness (T2) of the laminate (hereinafter also referred to as "laminate b") consisting of the layers from the diffusion prevention layer to the second stress relaxation layer located between and the polarizing layer is represented by the formula (1):
T1/T2≧1.5 (1)
is preferably satisfied. When the film thickness T1 of the laminate a and the film thickness T2 of the laminate b satisfy the formula (1), the laminate structure in which the second base film is peeled off and transferred to the substrate is more effectively formed. This makes it easier to reinforce the material, and further enhances the effect of suppressing the occurrence of lamination misalignment and wrinkles. From the viewpoint of enhancing such effects, the value of T1/T2 is more preferably 1.8 or more, still more preferably 2.0 or more, and may be 2.5 or more.

Further, in one embodiment of the present invention, the thickness T3 of the first base film and the thickness T2 of the laminate b are expressed by the formula (7):
T3/T2≧1.0 (7)
is preferably satisfied. When the thickness T3 of the first base film and the thickness T2 of the laminate b have a relationship that satisfies the expression (7), the laminate structure that is transferred to the substrate by peeling the second base film is more favorable. It is easy to be strongly reinforced, and the effect of suppressing the occurrence of lamination displacement and wrinkles can be further enhanced. From the viewpoint of enhancing such effects, the value of T3/T2 is more preferably 1.2 or more, still more preferably 1.5 or more, and may be 2.0 or more.

In one embodiment of the present invention, the peel force (F1) when peeling the laminate (laminate a) composed of the layers from the first base film to the first stress relaxation layer from the optical laminate, and the optical laminate The peel force (F2) when peeling the second base film from the formula (2):
0.02 (N/25mm)≦|F1−F2| (2)
is preferably satisfied.

When the peeling force F1 and the peeling force F2 satisfy the relationship represented by the formula (2), the adhesion force of the first stress relaxation layer in the optical laminate and the adhesion force of the second base film in the optical laminate There is a moderate strength relationship between Therefore, when the above relationship is satisfied, the second base film or the laminate a can be easily peeled off from the optical laminate in a desired order. In particular, when the second base film is first peeled off from the optical layered body, the second base film is easily peeled off, and lamination misalignment and wrinkles are less likely to occur during transfer to the transferred material. As a result, the effect of suppressing the deterioration of the optical performance of the optical layered body due to the transfer can be expected. The absolute value of F1-F2 in the present invention is preferably 0.03 N/25 mm or more, more preferably 0.04 N/25 mm or more, from the viewpoint that such effects can be more easily improved. The upper limit of the absolute value of F1-F2 is usually 0.3 N/25 mm or less, preferably 0.2 N/25 mm or less, more preferably 0.08 N/25 mm or less. The value of F1-F2 can be controlled by adjusting the release force F1 and the release force F2 respectively. Normally, the peel force F1 and the peel force F2 are designed so that the peel force on the side that is peeled earlier is smaller than the peel force on the side that is peeled later.

In the present invention, the peel force F1 is preferably less than 0.30 N/25 mm, more preferably 0.25 N/25 mm or less, even more preferably 0.15 N/25 mm or less. When the upper limit of the peeling force F1 is within the above range, the laminate a can be easily peeled off from the optical layered body, and the peeling force is set in a range effective for suppressing the occurrence of lamination misalignment and wrinkles in relation to the peeling force F2. Easy to control F1. Also, the peel force F1 is preferably 0.04 N/25 mm or more, more preferably 0.06 N/25 mm or more, and still more preferably 0.08 N/25 mm or more. When the peeling force F1 is equal to or more than the lower limit, it is possible to suppress unintended peeling of the laminate a before transfer to be incorporated into a display device or the like while ensuring easy peelability when peeling the laminate a from the optical laminate. can be done.

In the present invention, the peel force F2 is preferably less than 0.30 N/25 mm, more preferably 0.25 N/25 mm or less, even more preferably 0.15 N/25 mm or less. When the upper limit of the peeling force F2 is within the above range, the second substrate film can be easily peeled off from the optical layered body, and wrinkles and lamination misalignment that can occur when the second substrate film is peeled and transferred to the substrate. , the effect of suppressing the generation of air bubbles is likely to be improved. Also, the peel force F2 is preferably 0.01 N/25 mm or more, more preferably 0.02 N/25 mm or more, and still more preferably 0.03 N/25 mm or more. When the peeling force F2 is equal to or higher than the lower limit, while ensuring easy peelability when peeling the second base material film from the optical laminate, the second base material is not intended before transfer to incorporate the laminate into a display device or the like. Detachment of the film can be suppressed.

The peel forces F1 and F2 are respectively the base film or laminate on the opposite side of the base film whose peel force is to be measured in the optical laminate to be measured (for example, when measuring F1, the second base film, F2 At the time of measurement, a test piece in which the peeled surface of the laminate a) is fixed to a glass plate with an adhesive agent is used. It is a value measured as a peeling force required for peeling from the optical laminate of . The peel force can be measured according to the 90° peel test method specified in JIS K 6854-1:1999. A detailed method for measuring the peeling forces F1 and F2 will be described in Examples below.

The peel force F1 and the peel force F2 are determined, for example, by the structure and thickness of the layers adjacent to the laminate a and the second base film, the types and thicknesses of the first stress relaxation layer and the second base film, and the thickness of the first stress relaxation layer and the second base film. The stress relaxation layer, the second base film and/or the surface treatment of these layers or the layer adjacent to the base film can be adjusted. For example, by modifying the surface of the first stress relaxation layer and/or the second base film or providing a release force adjusting layer as an adjacent layer, the laminate a or the second base film The release force from the optical laminate can be controlled.

In the optical layered body of the present invention, both the peelable layered body a and the peelable second base film constituting the optical layered body are peeled off, and only the layered structure having a circularly polarizing plate function is covered. It is used by transferring it to a transfer body. The optical laminate of the present invention includes the first stress relaxation layer and the second stress relaxation layer, and is excellent in suppressing the occurrence of wrinkles and lamination displacement when the base film is peeled off and transferred to the substrate. . The optical layered body of the present invention can be produced by using a general apparatus conventionally and widely used in the relevant field for manufacturing an optical film, an optical layered body, etc., and obtaining the layered body a and the second base film as desired. They can be continuously and easily peeled off from the optical layered body in the order of application.

Although the optical laminate of the present invention is thin, lamination misalignment and wrinkles due to peeling of the base film are unlikely to occur, and high optical performance can be expected in the laminate after transfer. Therefore, the optical laminate of the present invention can be suitably used for manufacturing various display devices.
A display device is a device having a display element, and includes a light-emitting element or a light-emitting device as a light source. Examples of display devices include liquid crystal displays, organic electroluminescence (EL) displays, inorganic electroluminescence (EL) displays, touch panel displays, electron emission displays (e.g. field emission displays (FED), surface field emission displays). (SED)), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection display device (e.g. grating light valve (GLV) display device, display device having digital micromirror device (DMD) ) and piezoelectric ceramic displays, etc. Liquid crystal display devices include transmissive liquid crystal display devices, semi-transmissive liquid crystal display devices, reflective liquid crystal display devices, direct view liquid crystal display devices, projection liquid crystal display devices, and the like. These display devices may be display devices that display two-dimensional images, or may be stereoscopic display devices that display three-dimensional images.

The present invention will be described in more detail below with reference to examples and comparative examples. "%" and "parts" in Examples and Comparative Examples are "% by mass" and "parts by mass" unless otherwise specified.

1. Production of Laminate A1 (1) Preparation of Water-Soluble Polymer (1) According to the following synthesis scheme, a water-soluble polymer (1) composed of the following structural units was obtained.

In 400 g of dimethyl sulfoxide, 20 g of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) having a molecular weight of 1000, 0.55 mg of N,N-dimethyl-4-aminopyridine as a nucleophile, and 4.6 g of triethylamine are dissolved, The temperature was raised to 60° C. while stirring. Thereafter, a solution of 10.5 g of methacrylic anhydride dissolved in 50 g of dimethylsulfoxide was added dropwise over 1 hour, and the mixture was reacted by heating and stirring at 60° C. for 14 hours. After cooling the obtained reaction solution to room temperature, 481 g of methanol was added to the reaction solution and stirred so as to be completely mixed, so that the ratio (mass) of the reaction solution and methanol was adjusted to 1:1. did. By gradually adding 1500 mL of acetone to this solution, the water-soluble polymer (1) was crystallized by a crystallization method. 20.2 g of water-soluble polymer (1) was obtained by filtering the obtained solution containing the white crystals, washing well with acetone, and drying in vacuum. The obtained water-soluble polymer (1) was dissolved in water to prepare a 3% by mass aqueous solution of water-soluble polymer (1).

・溶剤：ｏ－キシレン ９８部 (2) Preparation of Composition for Forming Photo-Alignment Film A composition for forming a photo-alignment film was obtained by mixing the following components and stirring the resulting mixture at 80° C. for 1 hour.
- Photo-alignable polymer: polymer described in JP-A-2013-033249 (number average molecular weight: about 28200, Mw / Mn: 1.82) 2 parts

・Solvent: 98 parts of o-xylene

・重合性液晶化合物：Ａ２ ２５部

・二色性色素：アゾ色素１ ２．５部

・二色性色素：アゾ色素２ ２．５部

・二色性色素：アゾ色素３ ２．５部

・重合開始剤：２－ジメチルアミノ－２－ベンジル－１－（４－モルホリノフェニル）ブタン－１－オン（イルガキュア３６９；チバ・スペシャルティ・ケミカルズ(株)製） ６部
・レベリング剤：ポリアクリレート化合物（ＢＹＫ－３６１Ｎ；ＢＹＫ－Ｃｈｅｍｉｅ社製） １．２部
・溶剤：ｏ－キシレン ２５０部 (3) Preparation of Polarizing Layer-Forming Composition The following components were mixed and stirred at 80° C. for 1 hour to obtain a polarizing layer-forming composition. As the dichroic dye, an azo dye described in Examples of JP-A-2013-101328 was used.
・Polymerizable liquid crystal compound: A1 75 parts

・Polymerizable liquid crystal compound: 25 parts of A2

・ Dichroic dye: 2.5 parts of azo dye 1

- Dichroic dye: 2.5 parts of azo dye 2

・ Dichroic dye: 2.5 parts of azo dye 3

・Polymerization initiator: 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals Co., Ltd.) 6 parts ・Leveling agent: polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) 1.2 parts Solvent: o-xylene 250 parts

・重合性液晶化合物：Ｘ２ ３３部

・重合開始剤：２－ジメチルアミノ－２－ベンジル－１－（４－モルホリノフェニル）ブタン－１－オン（イルガキュア（登録商標）３６９；ＢＡＳＦジャパン社製） ８部
・レベリング剤：ポリアクリレート化合物（ＢＹＫ－３６１Ｎ；ＢＹＫ－Ｃｈｅｍｉｅ社製） ０．１部
・その他の添加剤：ＬＡＬＯＭＥＲ ＬＲ９０００（ＢＡＳＦジャパン社製） ６．７部
・溶剤：シクロペンタノン ５４６部
・溶剤：Ｎ－メチルピロリドン ３６４部 (4) Preparation of Retardation Layer-Forming Composition The following components were mixed and stirred at 80° C. for 1 hour to obtain a retardation layer-forming composition.
・Polymerizable liquid crystal compound: X1 100 parts

・Polymerizable liquid crystal compound: 33 parts of X2

・ Polymerization initiator: 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl) butan-1-one (Irgacure (registered trademark) 369; manufactured by BASF Japan) 8 parts ・ Leveling agent: Polyacrylate compound ( BYK-361N; manufactured by BYK-Chemie) 0.1 parts Other additives: LALOMER LR9000 (manufactured by BASF Japan) 6.7 parts Solvent: Cyclopentanone 546 parts Solvent: N-methylpyrrolidone 364 parts

(5) Production of polarizing plate (1) Release polyethylene terephthalate (PET) film (“FF-50” manufactured by Unitika Ltd., single-sided release-treated PET film, thickness of substrate: 50 μm) as substrate 1. A 3% by mass aqueous solution of the water-soluble polymer (1) prepared above was applied to the release-treated surface with a bar coater and dried at 100 ° C. for 2 minutes to form a 2 μm anti-diffusion film consisting of the water-soluble polymer (1). Layer A was formed.

After performing a plasma treatment on the surface of the obtained diffusion prevention layer A, the composition for forming a photo-alignment film was applied using a bar coater to form a coating film. The coating film was dried at 100° C. for 2 minutes to remove the solvent and form a dry film. The dry film was irradiated with polarized UV light at an intensity of 20 mJ/cm ² (313 nm standard) to impart an alignment regulating force to form a photo-alignment film A of 50 nm.

On the obtained photo-alignment film A, the composition for forming a polarizing layer was applied using a bar coater to form a coating film. Furthermore, the solvent was removed by drying at 110° C. for 2 minutes, and the polymerizable liquid crystal compound was phase-transitioned to a liquid phase, and then cooled to room temperature to phase-transition the polymerizable liquid crystal compound to a smectic liquid crystal state. . Thereafter, the obtained dry film is irradiated with ultraviolet light at 1000 mJ/cm ² (365 nm standard) using a high-pressure mercury lamp to polymerize the polymerizable liquid crystal compound contained in the dry film while maintaining the smectic liquid crystal state. to form a 3 μm polarizing layer.

Next, after performing a plasma treatment on the formed polarizing layer, a 3% by mass aqueous solution of the water-soluble polymer (1) was applied using a bar coater, dried at 100° C. for 2 minutes, and the water-soluble polymer ( A 2 μm-thick anti-diffusion layer B composed of the film of 1) was formed to obtain a polarizing plate (1) composed of substrate 1/diffusion-preventing layer A/photo-alignment film A/polarizing layer/diffusion-preventing layer B.

(6) Production of retardation film (1) Release polyethylene terephthalate (PET) film as substrate 2 (“FF-50” manufactured by Unitika Ltd., single-sided release-treated PET film, thickness of substrate: 50 μm) After subjecting the surface opposite to the release-treated surface to corona treatment, the composition for forming a photo-alignment film was applied using a bar coater. The resulting coating film was dried at 120° C. for 2 minutes and then cooled to room temperature to form a dry film. Thereafter, 100 mJ of polarized ultraviolet light (313 nm standard) was irradiated to form a photo-alignment film B of 100 nm.

On the obtained photo-alignment film B, the composition for forming a retardation layer was applied by a bar coater to form a coating film. This coating film was dried by heating at 120° C. for 2 minutes and then cooled to room temperature to obtain a dry film. Then, using an ultraviolet light irradiation device, the dry film was irradiated with ultraviolet light at an exposure amount of 1000 mJ/cm ² (365 nm standard), thereby aligning the polymerizable liquid crystal compound in the horizontal direction with respect to the substrate surface. A 2 μm retardation layer cured in this state was formed to obtain a retardation film (1) consisting of substrate 2/photo-alignment film B/retardation layer (horizontally aligned liquid crystal cured layer).

(7) Preparation of laminate A1 The anti-diffusion layer B surface of the polarizing plate (1) prepared above and the retardation layer surface of the retardation film (1) are attached to each other with an adhesive (manufactured by Lintec Corporation, pressure-sensitive adhesive 5 μm Thickness), the angle formed by the absorption axis of the polarizing plate (1) and the slow axis of the retardation film (1) is 45 °, substrate 1 / anti-diffusion layer A / light A laminate A1 consisting of alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/photo alignment film B/substrate 2 was obtained.

2. Preparation of laminate A2 (1) Preparation of oriented polymer composition (1) According to the composition shown in Table 1, 2-butoxyethanol is added to Sanever SE-610 (manufactured by Nissan Chemical Industries, Ltd.), which is a commercially available oriented polymer. Additionally, an oriented polymer composition (1) was prepared. In addition, the value in Table 1 represents the content ratio of each component with respect to the total amount of the prepared composition. For SE-610, the solid content was converted from the concentration described in the delivery specifications.

(2) Preparation of vertically aligned liquid crystal cured layer forming composition Table 2 shows the composition of the vertically aligned liquid crystal cured layer forming composition. After mixing each component and stirring the obtained solution at 80 degreeC for 1 hour, it cooled to room temperature and obtained the composition for vertical alignment liquid-crystal cured layer forming.

The values in parentheses in Table 2 represent the content ratio of each component with respect to the total amount of the prepared composition.
LR9000 in Table 2 is Laromer (registered trademark) LR-9000 manufactured by BASF Japan, Irg907 is Irgacure (registered trademark) 907 manufactured by BASF Japan, BYK361N is a leveling agent manufactured by BYK Chemie Japan, LC242 represents a polymerizable liquid crystal manufactured by BASF Corporation represented by the following formula, and PGMEA represents propylene glycol 1-monomethyl ether 2-acetate.

(3) Production of Laminate Containing Cured Layer of Vertically Aligned Liquid Crystal As the base material 3, the surface of a cycloolefin polymer film (COP) (ZF-14, manufactured by Nippon Zeon Co., Ltd.) was treated with a corona treatment apparatus with an output of 0.00. The treatment was performed once under the conditions of 3 kW and a treatment speed of 3 m/min. The alignment polymer composition (1) was applied to the corona-treated surface using a bar coater and dried at 90° C. for 1 minute to obtain alignment film C. The film thickness of the resulting alignment film C was measured with a laser microscope and found to be 1 μm. Then, a composition for forming a vertically aligned liquid crystal cured layer was applied on the alignment film C using a bar coater, dried at 90° C. for 1 minute, and then irradiated with ultraviolet rays using a high-pressure mercury lamp (under nitrogen atmosphere, wavelength 365 nm). integrated light intensity at 1000 mJ/cm ² ) to form a vertically aligned liquid crystal cured layer with a thickness of 500 nm in which the polymerizable liquid crystal compound is cured in a state aligned in the direction perpendicular to the plane of the substrate; A laminate consisting of alignment film C/cured layer of vertically aligned liquid crystal was obtained.

(4) Preparation of adhesive layer-forming curable composition A cationically polymerizable adhesive layer-forming curable composition is prepared by mixing a cationic polymerizable compound and a cationic polymerization initiator described below, followed by defoaming. did.
The cationic polymerization initiator was blended as a 50% by mass propylene carbonate solution, and the solid content is shown.
· 1,6-hexanediol diglycidyl ether (trade name: EX-212L, manufactured by Nagase ChemteX Corporation) 25 parts · 4-hydroxybutyl vinyl ether 10 parts · Bisphenol F type epoxy resin (trade name: EXA-830CRP, DIC Corporation) 65 parts Cationic polymerization initiator (trade name: CPI-100P, San-Apro Co., Ltd., 50% by mass solution) 3 parts

(5) Production of Laminate A2 After applying corona treatment to the surface of the vertically aligned liquid crystal cured layer of the laminate consisting of substrate 3 / alignment film C / vertically aligned liquid crystal cured layer produced above, the substrate of laminate A1 was applied. The surface exposed by peeling off the material 2 and the surface of the vertically aligned liquid crystal cured layer subjected to the corona treatment are bonded via the adhesive layer forming curable composition, and a UV irradiation device (SPOT CURE SP- 7; manufactured by Ushio Inc.) was used to irradiate ultraviolet rays at an exposure amount of 500 mJ/cm ² (365 nm standard). As a result, substrate 1/diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/photo-alignment film B/adhesive layer/vertical alignment liquid crystal cured layer/alignment film C/ A laminate A2 composed of the base material 3 was obtained. The thickness of the adhesive layer was 2 μm.

3. Preparation of Laminate Containing Stress Relief Layer (1) Polymerization Example 1: Preparation of Acrylic Resin Solution (1) Nitrogen gas was introduced into a reactor equipped with a stirrer, thermometer, reflux cooling, and a nitrogen introduction tube for reaction. The air in the apparatus was replaced with nitrogen gas. Then, 93 parts of 2-ethylhexyl acrylate, 5.5 parts of 8-hydroxyoctyl acrylate, 1.5 parts of acrylic acid, and 60 parts of a solvent (ethyl acetate) were added to the reactor. Thereafter, 0.1 part of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours, and reaction was carried out at 65° C. for 6 hours to obtain an acrylic resin solution (1). The acrylic polymer contained in the acrylic resin solution (1) had a weight average molecular weight of about 500,000 in terms of standard polystyrene by gel permeation chromatography.

(2) Polymerization Example 2: Preparation of acrylic resin solution (2) Into a reactor equipped with a cooling pipe, a nitrogen inlet pipe, a thermometer and a stirrer, 81.8 parts of acetone, 98.4 parts of butyl acrylate and 0 acrylic acid were added. A mixed solution of 0.6 part and 1.0 part of 2-hydroxyethyl acrylate was charged, and the internal temperature was raised to 55° C. while replacing the air in the apparatus with nitrogen gas to make it oxygen-free. Thereafter, a solution obtained by dissolving 0.14 parts of azobisisobutyronitrile (polymerization initiator) in 10 parts of acetone was added to the whole amount. One hour after the addition of the polymerization initiator, the inner temperature was increased to 54 while continuously adding acetone to the reactor at an addition rate of 17.3 parts/hr so that the concentration of the acrylic resin excluding the monomers was 35%. The temperature was maintained at ~56°C for 12 hours, and finally ethyl acetate was added to adjust the concentration of the acrylic resin to 20%. Thus, an acrylic resin solution (2) was obtained.

(3) Preparation of laminate A3 containing stress relaxation layer A (i) Preparation of composition (1) for forming stress relaxation layer 100 parts of acrylic polymer contained in acrylic resin solution (1) obtained in Polymerization Example 1 above Then, add 2.0 parts of 1-octylpyridinium dodecylbenzenesulfonate as an antistatic agent and stir, then add 1.5 parts of Coronate HX (isocyanurate of hexamethylene diisocyanate compound: manufactured by Tosoh Corporation). In addition, they were stirred and mixed to obtain a composition (1) for forming a stress relaxation layer.

(ii) Preparation of laminate A3 containing stress relaxation layer The stress relaxation layer-forming composition (1) was applied on a separate film (substrate B) having a thickness of 15 µm made of a polyethylene terephthalate (PET) film coated with a silicone resin. After coating, the solvent was removed by drying at 90° C. to form a stress relaxation layer A having a thickness of 15 μm after drying. Then, the surface opposite to the antistatic and antifouling treated surface of a 38 μm-thick polyethylene terephthalate (PET) film (substrate A) having one surface subjected to antistatic and antifouling treatments was laminated on the stress relieving layer A to prepare a laminate A3 comprising the stress relieving layer A consisting of base material A/stress relieving layer A/base material B.

(4) Preparation of laminate A4 containing stress relaxation layer A Except for using a 75 μm thick PET film (substrate C) that has been subjected to antistatic treatment and antifouling treatment, the base material A/stress relaxation layer A In the same manner as the laminate A3 consisting of /base material B, a laminate A4 including a stress relaxation layer A consisting of base material C/stress relaxation layer A/base material B was produced.

(5) Preparation of laminate A5 containing stress relaxation layer B Base material A except that 2.0 parts of 1-octylpyridinium dodecylbenzenesulfonate was not blended in the stress relaxation layer-forming composition (1) In the same manner as the laminate A3 consisting of /stress relaxation layer A/base material B, a laminate A5 comprising a stress relaxation layer B comprising base material A/stress relaxation layer B/base material B was produced.

(6) Preparation of Laminate A6 Including Stress Relaxation Layer C (i) Preparation of Stress Relaxation Layer-Forming Composition (2) A stress relaxation layer-forming composition (2) was prepared according to the following composition.
- Acrylic resin solution (2) obtained in Polymerization Example 2: 100 parts (non-volatile content)
・ Isocyanate compound: Coronate L, ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%) (manufactured by Tosoh Corporation) 0.5 parts ・ Silane compound: KBM-403, 3-Gly 0.5 part of sidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed, and ethyl acetate was added so that the solid content concentration was 10%, to prepare the composition for forming a stress relaxation layer (2). Obtained.

(ii) Preparation of laminate A6 containing stress relaxation layer C The stress relaxation layer-forming composition (2) was applied to the release-treated surface of a release-treated polyethylene terephthalate film (thickness: 38 µm) (substrate D), It was applied using an applicator so that the thickness after drying would be 15 μm. The coated layer was dried at 100° C. for 1 minute to obtain a film with a stress relieving layer C. After that, a release-treated polyethylene terephthalate film (thickness: 38 μm) (base material D) was laminated on the stress relaxation layer C, and cured for 7 days under conditions of a temperature of 23° C. and a relative humidity of 50% RH. A laminate A6 having a stress relaxation layer C composed of D/stress relaxation layer C/base material D was produced.

4. Preparation of Optical Laminate (1) Example 1
Substrate 1 / anti-diffusion layer A / photo-alignment film A / polarizing layer / anti-diffusion layer B / adhesive layer / retardation layer / photo-alignment film B / substrate 2 The substrate 2 of the laminate A1 is peeled off The exposed surface and the surface exposed by peeling the substrate D of the laminate A6 composed of the substrate D/stress relaxation layer C/substrate D are bonded, and the substrate 1/diffusion prevention layer A/photo alignment An optical laminate B1 consisting of film A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/photo-alignment film B/stress relaxation layer C/substrate D was produced. Furthermore, the surface exposed by peeling off the base material 1 of the optical layered body B1 and the exposed surface by peeling off the base material B of the layered body A3 composed of the base material A/stress relaxation layer A/base material B are separated. Bonding, substrate A/stress relaxation layer A/diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/photo-alignment film B/stress relaxation layer C/substrate An optical laminate (1) composed of D was obtained.

(2) Example 2
Substrate 1/diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/photo-alignment film B/adhesive layer/vertical alignment liquid crystal cured layer/alignment film C/substrate 3 The surface exposed by peeling the base material 3 of the laminate A2 consisting of Then, substrate 1 / diffusion prevention layer A / photo-alignment film A / polarizing layer / diffusion prevention layer B / adhesive layer / retardation layer / photo-alignment film B / adhesive layer / vertically aligned liquid crystal cured layer / alignment film C / stress An optical laminate B2 consisting of the relaxation layer C/substrate D was produced. Furthermore, the surface exposed by peeling off the base material 1 of the optical layered body B2 and the surface exposed by peeling off the base material B of the layered body A3 composed of the base material A/stress relaxation layer A/base material B are separated. Bonding, substrate A / stress relaxation layer A / diffusion prevention layer A / photo-alignment film A / polarizing layer / diffusion prevention layer B / adhesive layer / retardation layer / photo-alignment film B / adhesive layer / vertical alignment liquid crystal curing An optical laminate (2) consisting of layer/alignment film C/stress relaxation layer C/substrate D was obtained.

(3) Example 3
Except that the laminate A4 was used instead of the laminate A3, and the surface exposed by peeling the substrate 1 of the optical laminate B1 and the surface exposed by peeling the substrate B of the laminate A4 were bonded together. In the same manner as in Example 1, substrate C/stress relaxation layer A/diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/photo-alignment film B/stress relaxation layer An optical laminate (3) consisting of C/substrate D was obtained.

(4) Example 4
Except that the laminate A4 was used instead of the laminate A3, and the surface of the optical laminate B2 exposed by peeling off the base material 1 and the exposed surface of the laminate A4 by peeling off the base material B were bonded together. In the same manner as in Example 2, substrate C / stress relaxation layer A / diffusion prevention layer A / photo-alignment film A / polarizing layer / diffusion prevention layer B / adhesive layer / retardation layer / photo-alignment film B / adhesive layer / An optical laminate (4) consisting of a vertically aligned liquid crystal cured layer/alignment film C/stress relaxation layer C/substrate D was obtained.

(5) Example 5
The laminate A5 was used instead of the laminate A3, and the surface exposed by peeling the base material 1 of the laminate B1 and the surface exposed by peeling the base material B of the laminate A5 were bonded together. In the same manner as in Example 1, substrate A/stress relaxation layer B/diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/photo-alignment film B/stress relaxation layer C / An optical layered body (5) composed of the substrate D was obtained.

(6) Comparative Example 1
The substrate 1 of the optical laminate B1 prepared in the same manner as in Example 1 was peeled off, and diffusion prevention layer A/photo alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/orientation An optical laminate (6) consisting of film B/stress relaxation layer C/substrate D was obtained.

5. Physical properties/characteristic evaluation of optical laminate (1) Elastic modulus of first base film (23°C)
A test piece having an MD length of 100 mm and a TD length of 25 mm was cut out from the base film. Then, both ends of the test piece in the long side direction were clamped with upper and lower grips of a tensile tester [AUTOGRAPH AG-1S tester manufactured by Shimadzu Corporation] so that the distance between the grips was 5 cm, and the temperature was 23 ° C. In an environment with a relative humidity of 55%, the test piece is pulled in the long side direction at a tensile speed of 1 mm / min, and the resulting stress - From the slope of the initial straight line in the strain curve, the tensile modulus [MPa] in MD at 23 ° C. Calculated.

(2) Peeling force of the laminate (laminate a) consisting of the first base film and the first stress relaxation layer, and peeling force of the second base film Optics prepared in Examples 1 to 5 and Comparative Example 1 In the laminates (1) to (6), the substrate on the polarizing layer side is the first substrate film, the substrate on the retardation side is the second substrate film, and stress relaxation adjacent to the first substrate film is performed. The peeling force F1 when peeling the layered body a composed of the layers up to the layer from the optical layered body and the peeling force F2 when peeling the second base film from the optical layered body are measured by the following methods. did. Table 3 shows the results.
Using a tensile tester, grab one end of the test piece (width 25 mm × length about 150 mm) in the length direction, under an atmosphere of temperature 23 ° C. and relative humidity 60%, crosshead speed (grip movement speed) 200 mm / min. JIS K 6854-1:1999 "Adhesive-Peeling adhesive strength test method-Part 1: 90 degree peeling" was performed and measured.

(3) Lamination test Each of the optical laminates (1) to (6) produced in Examples and Comparative Examples was cut into a sheet of 160 mm × 80 mm, and a Haltech (“Haltec HAL650” manufactured by Sankyo Co., Ltd.) was used. , the second substrate film was peeled off while the surface of the first substrate film was adsorbed, and the exposed surface of the second stress relaxation layer was bonded to the glass. After that, the appearance is inspected, and if defects in appearance (lamination air bubbles, wrinkles, lifting or tearing of the first base material) are confirmed, lamination is failed, and if no defects in appearance are confirmed, lamination is successful, and the test is performed. was performed 20 times. The test results were classified according to the success rate. Table 3 shows the results.
<Evaluation Criteria>
○: Success rate of 90% or more △: Success rate of 60% or more and less than 90% ×: Success rate of less than 60%

The thickness T1 of the laminate a in Table 3 is the total thickness of the laminate consisting of the layers from the first base film to the first stress relaxation layer, and the thickness T2 of the laminate b is the first stress It is the total thickness of the laminate consisting of the layers from the anti-diffusion layer located between the relaxation layer and the polarizing layer to the second stress relaxation layer (for T1 and T2, the thickness in the table is rounded to the first decimal place. value). In addition, the thickness of the layer between the first stress relaxation layer and the Agent 2 stress relaxation layer does not include the thicknesses of the first stress relaxation layer and the second stress relaxation layer.

1: First base film 2: First stress relaxation layer 3: Polarizing layer 4: Adhesive layer 5: Retardation layer 6: Second stress relaxation layer 7: Second base film 8, 9: Diffusion prevention layer 11: Optical laminate 12, 13: laminate structure

Claims (9)

An optical laminate comprising a first substrate film, a first stress relaxation layer, a polarizing layer, an adhesive layer, a retardation layer, a second stress relaxation layer, and a second substrate film in this order,
The total thickness of the layers located between the first stress relaxation layer and the second stress relaxation layer is 20 μm or less,
The elastic modulus of the first base film at 23° C. is 2,500 to 6,000 MPa,
A substrate film in which the first stress relaxation layer can be peeled off from the layer adjacent to the surface of the first stress relaxation layer opposite to the first base film, and the second substrate film can be peeled off. is an optical laminate. 2. The optical stack of claim 1, further comprising an anti-diffusion layer between the first stress relieving layer and the polarizing layer. 3. The optical laminate according to claim 1, wherein the polarizing layer is a cured liquid crystal layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting a smectic liquid crystal phase and a dichroic dye. 4. The optical laminate according to any one of claims 1 to 3, wherein the retardation layer is a horizontally aligned liquid crystal cured layer in which a polymerizable liquid crystal compound is cured in a state of being horizontally aligned with respect to the plane of the substrate. 5. The optical laminate according to claim 1, wherein the thickness of the first base film is 30-120 μm. The thickness (T1) of the laminate (laminate a) consisting of the layers from the first base film to the first stress relaxation layer, and the diffusion prevention layer positioned between the first stress relaxation layer and the polarizing layer to the first The film thickness (T2) of the laminate (laminate b) consisting of layers up to 2 stress relaxation layers is represented by the formula (1):
T1/T2≧1.5 (1)
The optical laminate according to any one of claims 2 to 5, which satisfies Peel force (F1) when peeling the laminate (laminate a) consisting of the layers from the first base film to the first stress relaxation layer from the optical laminate, and peeling the second base film from the optical laminate The peel force (F2) when doing is the formula (2):
0.02 (N/25mm)≦|F1−F2| (2)
The optical laminate according to any one of claims 1 to 6, which satisfies 8. The optical laminate according to claim 2, wherein the anti-diffusion layer has a thickness of 5 μm or less. 9. Any one of claims 1 to 8, further comprising a vertically aligned liquid crystal cured layer in which the polymerizable liquid crystal compound is cured in a state of being vertically aligned with respect to the plane of the substrate, between the polarizing layer and the second stress relaxation layer. The optical laminate according to any one of the above.

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