KR20230172475A - optical laminate - Google Patents

Abstract

The purpose is to provide an optical laminated body that is thin and can be easily transferred to any transfer target body by suppressing the occurrence of bonding misalignment or wrinkles when transferring to a transfer target body. An optical laminate comprising a first base film, a first stress relief layer, a polarizing layer, a point adhesive layer, a retardation layer, a second stress relief layer, and a second base film in this order, wherein the first stress relief layer and the second Optical lamination, wherein the total thickness of the layers located between the stress relief layers is 20 μm or less, the storage modulus of the first stress relief layer is 1.5 MPa or less, and both the first base film and the second base film are peelable base films. sifter.

Description

optical laminate

The present invention relates to a transferable optical laminate.

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

Japanese Patent Publication No. 2014-63143 Japanese Patent Publication No. 2017-83843 Japanese Patent Publication No. 2020-56834 Japanese Patent Publication No. 2019-91088 Japanese Patent Publication No. 2020-13164

The optical laminate as disclosed in the above patent document transfers an optically anisotropic layer formed on a substrate to a transfer target, that is, peeling the substrate and bonding it to the transfer target through a point adhesive layer or the like. By doing so, it can be mounted on a display device, etc.

However, as the optical laminate becomes thinner, handling tends to become difficult, and when peeling the substrate and transferring the optically anisotropic layer to the transfer target, problems such as bonding misalignment or wrinkles may occur.

The purpose of the present invention is to provide an optical laminated body that is thin and can be easily transferred to any transfer target by suppressing the occurrence of misalignment or wrinkles when transferring to a transfer target.

As a result of intensive studies to solve the above problems, the present inventors and others have completed the present invention. That is, the present invention includes the following aspects.

[1] An optical laminate comprising a first base film, a first stress relief layer, a polarizing layer, a point adhesive layer, a retardation layer, a second stress relief layer, and a second base film in this order,

The total thickness of the layers located between the first stress relief layer and the second stress relief layer is 20 μm or less,

The storage modulus of the first stress relief layer is 1.5 MPa or less,

An optical laminate wherein both the first base film and the second base film are peelable base films.

[2] The optical laminate according to [1], further comprising a diffusion prevention layer between the first stress relief layer and the polarizing layer.

[3] The optical laminate according to [1] or [2], wherein the polarizing layer is a liquid crystal cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting a smectic liquid crystalline phase and a dichroic dye.

[4] The optical laminate according to any one of [1] to [3], wherein the retardation layer is a horizontally aligned liquid crystal cured layer cured in a state in which a polymerizable liquid crystal compound is oriented horizontally with respect to the substrate surface.

[5] The optical laminate according to any one of [1] to [4], wherein the first base film has an elastic modulus of 2,500 to 6,000 MPa at 23°C.

[6] The optical laminate according to any one of [1] to [5], wherein the first stress relief layer has a thickness of 10 to 80 μm.

[7] The thickness of the first stress relief layer (T1) and the thickness of the second stress relief layer (T2) are equation (1):

T1/T2 ≥ 1.0 (1)

The optical laminate according to any one of [1] to [6], which satisfies the above.

[8] The peeling force (F1) when peeling the first base film from the optical laminate and the peeling force (F2) when peeling the second base film from the optical laminate are expressed in equation (2):

0.02 (N/25 ㎜) ≤ ｜F1 - F2｜ (2)

The optical laminate according to any one of [1] to [7], which satisfies the above.

[9] The optical laminate according to any one of [2] to [8], wherein the diffusion prevention layer has a thickness of 5 μm or less.

[10] [1] to [9] further comprising a vertically oriented liquid crystal cured layer in which the polymerizable liquid crystal compound is oriented in a direction perpendicular to the substrate surface between the polarizing layer and the second stress relief layer. The optical laminate according to any one of the above.

According to the present invention, it is possible to provide an optical laminated body that is thin and can be easily transferred to an arbitrary transfer target body by suppressing the occurrence of bonding misalignment or wrinkles when transferring to a transfer target body.

1 is a schematic cross-sectional view showing an example of the layer structure of the optical laminate of the present invention.
Fig. 2 is a schematic cross-sectional view showing an example of the layer structure of the optical laminate of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. In addition, the scope of the present invention is not limited to the embodiments described herein, and various changes can be made without impairing the spirit of the present invention.

The optical laminate of the present invention includes a first base film, a first stress relief layer, a polarizing layer, a point adhesive layer, a retardation layer, a second stress relief layer, and a second base film in this order. Hereinafter, an example of the layer structure of the optical laminated body of the present invention will be described based on FIGS. 1 and 2, but the laminated body of the present invention is not limited to these aspects.

The optical laminate 11 shown in FIG. 1 includes a first base film 1, a first stress relief layer 2, a polarizing layer 3, a point adhesive layer 4, a retardation layer 5, and a second stress relief layer. This is achieved by laminating the relief layer 6 and the second base film 7 in this order. In the optical layered body 11 shown in FIG. 1, the first base film 1 and the second base film 7 are each peelable, and a second peelable base film ( 7) is peeled off to form the first base film (1), first stress relief layer (2), polarizing layer (3), point adhesive layer (4), retardation layer (5), and second stress relief layer (6). The resulting laminate structure 12 can be transferred to a transfer target (substrate) such as an OLED substrate, for example. Thereafter, the first base film (1) is peeled and bonded to the front plate or the like via the first stress relief layer (2), thereby forming the first stress relief layer (2), the polarizing layer (3), and the adhesive layer (4). ), the retardation layer 5, and the second stress relief layer 6. A display device including a laminate structure 13 is obtained. In addition, the order of peeling the first base film and the second base film from the optical laminate of the present invention is not necessarily limited, but the effect of the present invention is more effective when the base film on the side bonded to the substrate is peeled first. Because it is significantly obtained, in one embodiment of the present invention, the second base film is first peeled and bonded to the substrate, and then the first base film is peeled.

In a preferred embodiment of the present invention, the optical laminate of the present invention further includes an anti-diffusion layer between the first stress relief layer and the polarizing layer. The optical laminate 11 shown in FIG. 2 has a diffusion prevention layer 8 between the first stress relief 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 surface of the polarizing layer 3 opposite to the first stress relaxation layer 2 may also have a diffusion prevention layer 9.

The optical laminate of the present invention, in addition to the first base film, the first stress relief layer, the polarizing layer, the point adhesive layer, the retardation layer, the second stress relief layer, the second base film, and the diffusion prevention layer, influences the effect of the present invention. As long as it does not affect, it may be configured to further include other layers. Other layers include, for example, an alignment film for forming a polarizing layer, an alignment film for forming a retardation layer, a second retardation layer, a point adhesive layer other than the point adhesive layer between the polarizing layer and the retardation layer, a resin layer having UV absorption ability, etc. can be mentioned.

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

[First base film and second base film]

The first base film and the second base film are layers laminated on the optical laminate so that peeling is possible. As the first base film and the second base film, for example, conventionally known resin films in the field of optical films can be used. Resins constituting the first base film and the second base film include, for example, polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; Cyclic olefin resin; polyvinyl alcohol; Polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; Polymethacrylic acid ester; Polyacrylic acid ester; Cellulose-based resins such as triacetylcellulose, diacetylcellulose, and cellulose acetate propionate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; Plastics such as polyphenylene sulfide and polyphenylene oxide can be mentioned. Among them, at least one selected from cellulose resin, cyclic olefin resin, and polyethylene terephthalate resin is preferable from the viewpoint of smoothness and quality as a coating substrate. These may be used individually, or may be used in combination of two or more types. Such a resin can be formed into a film by known means such as a solvent casting method or a melt extrusion method to form a resin film. The first base film and the second base film may be the same or different. In addition, in this specification, when simply referring to “base film”, the “base film” includes the first base film and the second base film.

In one embodiment of the present invention, the elastic modulus of the first base film at 23°C is preferably 2,500 to 6,000 MPa. If the elastic modulus of the first base film is more than the above lower limit, bubbles and wrinkles are unlikely to be generated when peeling off the second base film and transferring it to the substrate, and the effect of suppressing misalignment with the substrate tends to be excellent. In addition, if the modulus of elasticity is below the above upper limit, the balance of strength and rigidity against stress is good and has appropriate bending (in other words, it has appropriate elasticity and fracture is difficult to occur even when bent), so that the second base film can be peeled off to form a substrate. When transferring, the effect of suppressing misalignment with the substrate tends to be excellent. In the present invention, the elastic modulus of the first base film at 23°C is more preferably 3000 MPa or more, further preferably 3500 MPa or more, and even more preferably 5500 MPa or less.

In one embodiment of the present invention, the elastic modulus of the second base film at 23°C is preferably 2500 to 6000 MPa. If the elastic modulus of the second base film is within the above range, it is easy to ensure 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, further preferably 3500 MPa or more, and even more preferably 5500 MPa or less.

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

In order to provide the desired release property and adhesion to the film surface and to make it easier to control the peelability of the base film, the surface of the base film may be modified by corona treatment, plasma treatment, frame treatment, etc., depending on the composition of adjacent layers, etc. do. In the optical laminate of the present invention, when the first base film and the second base film are subjected to surface modification treatment, the treatment methods may be the same or different from each other.

The thickness of the first base film and the second base film may be appropriately determined depending on the structure of the base film, the structure of the layer adjacent to the base film, etc., but each is preferable from the viewpoint of film surface quality during application and drying. Preferably it is 20 ㎛ or more, more preferably 30 ㎛ or more, further preferably 40 ㎛ or more, and preferably 120 ㎛ or less, more preferably 100 ㎛ or less, and even more preferably 80 ㎛ 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 from each other.

The thickness of the base film can be measured by a laser microscope, a film thickness meter, etc., and hereinafter, the same applies to measuring the thickness of each layer or film, such as a polarizing layer or retardation layer, that constitutes the optical laminate.

A layer (hereinafter also referred to as “peel force adjustment layer”) having a function of controlling the peeling force when peeling the base film from the optical laminate may be formed on the side adjacent to the stress relief layer of the base film. When forming a peeling force adjustment layer, the peeling force adjusting layer formed on the first base film and the second base film may be the same or different from each other.

The peeling force adjusting layer is, for example, a composition for forming a peeling force adjusting layer containing a component that can adjust the adhesion of the base film to the stress relief layer laminated on the surface of the resin film serving as the base film. It can be formed by applying it. As the peeling force adjustment layer, materials conventionally known in the field can be used as long as the desired peeling force can be secured. In the present invention, the composition for forming a peeling force adjusting layer capable of forming a peeling force adjusting layer includes, for example, a solution containing a silane compound; A solution containing silica powder, etc.; Curable resin composition; and compositions containing release materials such as fluorine-based materials, long-chain alkyl-based materials, and fatty acid amide-based materials. Among these, it is preferable to form a thin film from a solution containing a silane compound from the viewpoint of easily forming a layer that can provide the desired peeling force.

Silane compounds that can form the peeling force adjustment layer include, for example, silicon polymers such as polysilanes, silicone resins such as silicone oils and silicone resins, and organic-inorganic silanes such as silicone oligomers, silcesiloxanes, and alkoxysilanes. Compounds, more specifically, nonionic compounds containing Si elements such as silane coupling agents, can be mentioned. These silane compounds may be used individually, or may be used in combination of two or more types. Among them, silane coupling agents are preferable.

The silane coupling agent is preferably a silane compound having at least one functional group selected from the group consisting of vinyl group, amino group, ureido group, mercapto group, (meth)acryloyl group, isocyanate group, imidazole group, and epoxy group. And, it is more preferable that it is a compound containing a Si element having at least one functional group and at least one alkoxysilyl group or silanol group. The vinyl group, amino group, ureido group, mercapto group, (meth)acryloyl group, isocyanate group, imidazole group, and epoxy group have polarity, and the adhesion between the base film and the stress relief layer is controlled by appropriately selecting these functional groups. can do. From this viewpoint, it is preferable that the silane coupling agent is a silane coupling agent having an alkoxysilyl group and at least one functional group described above. Additionally, the functional group may have a substituent or protecting group as appropriate in order to control the reactivity of the silane coupling agent.

Silane coupling agents specifically include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, and N-(2-aminoethyl)-3-aminopropylmethyl. Dimethoxysilane, 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-chloropropylmethyldimethoxy Silane, 3-chloropropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycylate Doxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, and 3-glycidoxypropylethoxydimethylsilane.

A commercially available silane coupling agent may be used, for example, KP321, KP323, KP324, KP326, KP340, KP341, 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 coupling agents manufactured by 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. I can hear it.

The layer containing a silane compound that functions as a peeling force adjustment 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 in the silane compound-containing solution can be appropriately selected depending on the solubility of the silane compound to be used. Specifically, for example, alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether, ethyl acetate, butyl acetate, and ethylene. Ester solvents such as glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate, and 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, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbons such as chloroform and chlorobenzene. Solvents, etc. can be mentioned. These solvents can be used individually or in combination of two or more types.

The content of the silane compound in the silane compound-containing solution is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, relative to the total mass of the silane compound-containing solution, from the viewpoint of easy control of the peeling force. Preferably it is 0.2 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, based on the total mass of the solution containing the silane compound.

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

Methods for applying a solution containing a silane compound to the surface forming the peeling force adjustment layer include, for example, spin coating, extrusion, gravure coating, die coating, bar coating, and applicator methods. and known methods such as printing methods such as the flexographic method.

Drying methods 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. Each condition, such as drying temperature and drying time, can be appropriately determined depending on the composition of the silane compound-containing solution, the material of the base film, etc.

The thickness of the layer containing the silane compound that functions as a peeling force adjustment layer is usually 10 nm to 1000 nm, preferably 10 nm to 500 nm, and 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 surface of the first base film on the polarizing layer side, and a second stress relaxation layer on the surface of the second base film on the retardation layer side. In the present invention, the stress relief layer is a layer formed on the surface on the polarizing layer side of the first base film and the surface on the retardation layer side of the second base film, and is used to peel the first base film and the second base film from the optical laminate. It refers to a layer that has the function of relieving the stress applied to the optical laminate. In the present invention, the first base film and the second base film each constitute an optical laminate with a stress relief layer interposed therebetween, and a stress relief layer is provided on the outer layers on both sides of the laminate structure mounted (transferred) in the display device. This exists. Due to this structure, the optical laminate of the present invention is excellent in suppressing wrinkles, bonding misalignment, and bubble generation that may occur when peeling the base film from a thin optical laminate and transferring it to a substrate. The reason is not clear, but when the base film is peeled from the optical laminate, the stress relief layers interact with each other to relieve the stress applied to the optical laminate, so that the stress relief layer does not exist or is only applied to one side. It is thought that the effect of suppressing the occurrence of bonding misalignment, wrinkles, etc. is higher than that of an optical laminate in which a stress relief layer is present. In order to sufficiently obtain this effect, in the optical laminate of the present invention, the first base film and the first stress relief layer, and the second base film and the second stress relief layer are respectively adjacent to each other, or only the peeling force adjustment layer is provided. It is preferable that they are disposed interposed. Additionally, in this specification, when simply referring to a “stress relaxation layer”, the “stress relaxation layer” includes the first stress relaxation layer and the second stress relaxation layer.

In the optical laminate of the present invention, the storage modulus of the first stress relief layer is 1.5 MPa or less. If the storage elastic modulus of the first stress relief layer exceeds 1.5 MPa, bubbles and wrinkles are likely to occur when the second base film is peeled off and transferred to the substrate, and bonding misalignment with the substrate tends to occur. In the present invention, the storage modulus of the first stress relief layer is preferably 0.8 MPa or less, more preferably 0.5 MPa or less, further preferably 0.4 MPa or less, particularly preferably 0.3 MPa or less. If the storage elastic modulus is below the above upper limit, the effect of suppressing bonding misalignment, wrinkles, bubbles, etc. when peeling and transferring the second base film to the substrate is improved, and while it is bonded to the first base film, the first base film While suppressing lifting, peelability can be ensured when peeling the first base film. The lower limit of the storage modulus of the first stress relief layer is not particularly limited, but is usually 0.005 MPa or more, preferably 0.01 MPa or more, more preferably 0.02 MPa or more, and still more preferably 0.04 MPa or more.

The storage modulus of the second stress relief layer is preferably 0.8 MPa or less, more preferably 0.5 MPa or less, further preferably 0.4 MPa or less, particularly preferably 0.3 MPa or less. If the storage elastic modulus is below the above upper limit, it is easy to ensure peelability when peeling the second base film while suppressing the lifting of the second base film. The lower limit of the storage modulus of the second stress relief layer is not particularly limited, but is usually 0.005 MPa or more, preferably 0.01 MPa or more, more preferably 0.02 MPa or more, and still more preferably 0.04 MPa or more.

The storage modulus of the stress relief layer can be measured using a viscoelasticity measuring device. In detail, for example, it can be measured by the method described in the Examples described later.

The stress relief layer can relieve the stress generated in the optical laminate at the time of peeling the base film, and after peeling the base film, it functions as an adhesive layer for bonding to a transfer object such as a substrate or front plate. It is preferable that it is a layer that does. The stress relief properties of the stress relief layer and the adhesion to the transfer object can be controlled depending on the type, content ratio, thickness, etc. of the components constituting the stress relief layer. A stress relief layer having such a function can be prepared using materials conventionally known in the field. For example, a composition containing a resin such as (meth)acrylic, rubber, urethane, ester, silicone, or polyvinyl ether as the main component (hereinafter also referred to as “composition for forming a stress relief layer”) can be mentioned. Among them, from the viewpoint of excellent transparency, adhesion, weather resistance, heat resistance, etc., it is preferable that the stress relief layer is formed of 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 a stress relief layer include butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethyl (meth)acrylate. A polymer or copolymer containing one or more types of (meth)acrylic acid ester such as hexyl as a monomer is preferably used. It is preferable to copolymerize a polar monomer with the base polymer. Polar monomers include, for example, (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, and N,N-dimethylaminoethyl (meth)acrylate. , monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as glycidyl (meth)acrylate.

In one embodiment of the present invention, the structural unit derived from (meth)acrylic acid ester in the (meth)acrylic resin constituting the stress relief layer is relative to the total mass of all structural units constituting the (meth)acrylic resin. , Preferably it is 80 to 99.9 mass%, more preferably 85 mass% or more, and even more preferably 90 mass% or more. In addition, when the (meth)acrylic resin includes a structural unit derived from a polar monomer, the structural unit derived from the polar monomer is 0.1 to 5 with respect to the total mass of all structural units constituting the (meth)acrylic resin. It is preferably mass%, more preferably 0.5 mass% or more, and even more preferably 3 mass% or less.

The (meth)acrylic resin constituting the stress relief layer can be manufactured by various known methods, such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. In the production of this acrylic resin, a polymerization initiator is usually used. 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 in the production of (meth)acrylic resin.

As a polymerization initiator, a thermal polymerization initiator, a photo polymerization initiator, etc. are used. As a thermal polymerization initiator, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile) Tril), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2' -Azo compounds such as azobis(2-methylpropionate) and 2,2'-azobis(2-hydroxymethylpropionitrile); Lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, tert-butyl peroxyneodecanoate. organic peroxides such as , tert-butylperoxypivalate, and (3,5,5-trimethylhexanoyl)peroxide; Examples include inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide. Examples of the photopolymerization initiator include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone.

When preparing an acrylic resin by solution polymerization, for example, the desired monomer and 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. There are ways to do this. Additionally, in order to control the reaction, the monomer or polymerization initiator may be added continuously or intermittently during polymerization, or may be added while dissolved in an organic solvent. Here, examples of the organic solvent include aromatic hydrocarbon-based solvents such as toluene and xylene; Ester solvents such as ethyl acetate and butyl acetate; Aliphatic alcohol-based solvents such as propyl alcohol and isopropyl alcohol; Ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone can be used.

The stress relief layer may contain only the acrylic resin described above, but may also be formed by using a crosslinking agent in combination. The crosslinking agent is a divalent or higher metal ion that forms a carboxylic acid metal salt between carboxyl groups; A polyamine compound that forms an amide bond between carboxyl groups; A polyepoxy compound or polyol that forms an ester bond between carboxyl groups; As a polyisocyanate compound, one that forms an amide bond between carboxyl groups is exemplified.

The stress relief layer is, for example, a composition for forming a stress relief layer in which the above-described acrylic resin as the main component is dissolved in a solvent, and is applied by a bar coating method on the base film or peeling force adjustment layer on which the stress relief layer is to be laminated. It can be formed by applying and drying. Examples of the solvent include the same solvents as those exemplified in the method for preparing acrylic resin.

The thickness of the stress relief layer may be appropriately determined depending on the structure of the stress relief layer, the structure or size of the display device, etc.

In one embodiment of the present invention, the thickness of the first stress relief layer is preferably 5 to 80 μm, more preferably 10 μm or more, further preferably 20 μm or more, and even more preferably 70 μm or more. It is ㎛ or less, more preferably 60 ㎛ or less. Moreover, the thickness of the second stress relief layer is preferably 5 to 80 μm, more preferably 10 μm or more, further preferably 20 μm or more, further preferably 60 μm or less, even more preferably is 40 ㎛ or less. The thickness of the first stress relief layer and the thickness of the second stress relief layer may be the same or different.

If the thickness of the first stress relief layer is thicker than the thickness of the second stress relief layer, the effect of suppressing misalignment, wrinkles, and bubbles, etc. when peeling and transferring the second base film to the substrate tends to increase. Accordingly, in one embodiment of the present invention, the thickness of the first stress relief layer (T1) and the thickness of the second stress relief layer (T2) are expressed in equation (1):

T1/T2 ≥ 1.0 (1)

It is desirable to satisfy. If the thickness of the first stress relief layer and the thickness of the second stress relief layer satisfy the relationship of the above equation (1), wrinkles that may occur when peeling the second base film from the thin optical laminate and transferring it to the substrate are eliminated. , the effect of suppressing bonding misalignment due to pulling and the generation of air bubbles is more likely to be improved. When the thickness of the first stress relief layer and the thickness of the second stress relief layer are different, the value of T1/T2 is more preferably 1.5 or more, further preferably 2.0 or more, and may be 3.0 or more.

[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 absorption anisotropy, and from the viewpoint of being advantageous for thinning the optical laminate, the polarizing layer in the optical laminate of the present invention is a coating layer and contains at least one type of liquid crystal compound. , preferably a cured layer formed of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye (hereinafter also referred to as “composition for forming a polarizing layer”).

The polymerizable liquid crystal compound (hereinafter also referred to as “polymerizable liquid crystal compound (A)”) contained in the composition for forming a polarizing layer that forms the polarizing layer of the present invention is a compound having at least one polymerizable group. Here, the polymerizable group refers to a group that can participate in the polymerization reaction by active radicals or acids generated from the polymerization initiator. 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, and oxiranyl group. , oxetanyl group, etc. Among these, a radical polymerizable group is preferable, a (meth)acryloyl group, a vinyl group, and a vinyloxy group are more preferable, and a (meth)acryloyl group is still more preferable. If the polymerizable liquid crystal compound forming the polarizing layer has the same functional group (polymerizable group) as the compound having the same functional group as the compound forming the alignment film for forming the polarizing layer described later, for example, a (meth)acryloyl group, the alignment film and the polarizing light The compatibility between layers is high, and excellent adhesion between layers can be achieved.

In the present invention, the polymerizable liquid crystal compound (A) is preferably a compound that exhibits smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizing layer with a high degree of orientation order can be formed. From the viewpoint of realizing a higher degree of orientation order, it is more preferable that the liquid crystal state exhibited by the polymerizable liquid crystal compound (A) is a high-order smectic phase (high-order smectic liquid crystal state). Here, the higher order Smectic phase means Smectic B phase, Smectic D phase, Smectic E phase, Smectic F phase, Smectic G phase, Smectic H phase, Smectic I phase, Smectic J phase, and Smectic phase. K phase and Smectic L phase, and among these, Smectic B phase, Smectic F phase and Smectic I phase are more preferable. The liquid crystal may be thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferable because it allows precise film thickness control. In addition, the polymerizable liquid crystal compound (A) may be a monomer, but may be an oligomer polymerized by a polymerizable group or a polymer.

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. A known polymerizable liquid crystal compound can be used, but a compound exhibiting smectic liquid crystallinity is preferred. Examples of such a polymerizable liquid crystal compound include a compound 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 equation (A1),

X ^{1 and} It may be substituted with an alkyl group of 4, a fluoroalkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, a cyano group or a nitro group, and the carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be an oxygen atom. Alternatively, it may be substituted with a sulfur atom or a nitrogen atom. However, at least one of X ¹ and X ² is a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent.

Y ¹ is a single bond or a divalent linking group.

n is 1 to 3, and when n is 2 or more, plural X ¹ may be the same or different. X ² may be the same as or different from any or all of a plurality of X ¹ . Moreover, when n is 2 or more, a plurality of Y ¹ may be the same or different from each other. From the viewpoint of liquid crystallinity, n is preferably 2 or more.

U ¹ represents a hydrogen atom or a polymerizable group.

U ² represents a polymerizable group.

W ¹ and W ² are independently a single bond or a divalent linking group.

V ¹ and V ² independently represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, and -CH ₂ - constituting the alkanediyl group is -O-, -CO-, -S It may be substituted with - or NH-.]

In the polymerizable liquid crystal compound (A1), X ^{1 and} -diyl group, and at least one of X ^{1 and} -1,4-diyl group is preferred. The substituents that the 1,4-phenylene group, which may have a substituent, or the cyclohexane-1,4-diyl group, which may have a substituent, optionally have, include alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, and butyl group, Halogen atoms such as cyano group, chlorine atom, and fluorine atom can be mentioned. Preferably, it is unsubstituted.

In addition, the polymerizable liquid crystal compound (A1) has the formula (A1-1) in 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.]

It is preferable that the portion represented by (hereinafter also referred to as partial structure (A1-1)) has an asymmetric structure because it is easy to develop smectic liquid crystallinity.

Examples of the polymerizable liquid crystal compound (A1) whose partial structure (A1-1) is an asymmetric structure include polymerizable liquid crystal compound (A1) where n is 1 and one X ¹ and one X ² have different structures. You can. In addition, a polymerizable liquid crystal 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 the two X ^1s (A1) ), a polymerizable liquid ^crystal compound ⁽ A1 ^{) in which X 1 bonded to} W ^{1 among} the two there is. In addition, as a compound in which n is 3 and three Y ¹ have the same structure, a polymerizable liquid crystal compound (A1) in which any one of the three X ¹ and one X ² has a structure different from all the other three can be mentioned. there is.

Y ¹ is -CH ₂ CH ₂ -, -CH ₂ O-, -CH ₂ CH ₂ O-, -COO-, -OCOO-, 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 a plurality of Y ¹ exists, Y ¹ bonded to X ² is -CH ₂ CH ₂ - or CH ₂ It is more preferable that it is O-. When both X ¹ and X ² have the same structure, it is preferable that two or more Y ^1s with different bonding methods exist. When a plurality of Y ^1s with different bonding methods exist, an asymmetric structure is formed, and smectic liquid crystallinity tends to occur.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, and is preferably a polymerizable group. It is preferable that both U ¹ and U ² are polymerizable groups, and it is preferable that both are radical polymerizable groups. Examples of the polymerizable group include the same groups as those previously exemplified 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 preferably a (meth)acryloyl group, and both are It is more preferable that it is a (meth)acryloyl group. In addition, the polymerizable group may be in a polymerized state or in an unpolymerized state, but is preferably in an unpolymerized state.

Alkanediyl groups represented by V ¹ and V ² include methylene group, ethylene group, propane-1,3-diyl group, butane-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, decane-1,10-diyl group, tetradecane-1,14-diyl group and icosane-1,20-diyl group. V ¹ and V ² are preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably an alkanediyl group having 6 to 12 carbon atoms.

Substituents that the alkanediyl group optionally has include a cyano group and a halogen atom, but the alkanediyl group is preferably unsubstituted, and more preferably is an unsubstituted linear alkanediyl group.

W ¹ and W ² are, independently of each other, preferably a single bond, -O-, -S-, -COO-, or -OCOO-, and 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. Known polymerizable liquid crystal compounds can be used, but those that exhibit smectic liquid crystallinity are preferred, and smectic liquid crystals are preferred. As a structure that tends to exhibit a property, it is preferable to have an asymmetric molecular structure in the molecular structure, and specifically, a polymerizable liquid crystal compound having the following partial structures (A-a) to (A-i), which exhibits smectic liquid crystallinity. It is more preferable that it is a liquid crystal compound. From the viewpoint of easy to exhibit high-order smectic liquid crystallinity, it is more preferable to have a partial structure of (A-a), (A-b), or (A-c). In addition, in (A-a) to (A-i) below, * represents a bond (single bond).

[Formula 1]

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 body.

[Formula 2]

[Formula 3]

[Formula 4]

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 member 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) is preferred. . As the polymerizable liquid crystal compound (A), one type may be used individually, or two or more types may be used in combination.

Polymerizable liquid crystal compounds (A) are described, for example, in Lub et al., Recl. Trav. Chim. It can be produced by a known method described in Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

In the present invention, the composition for forming a polarizing layer may contain a polymerizable liquid crystal compound other than the polymerizable liquid crystal compound (A), but from the viewpoint of obtaining a polarizing layer with a high degree of orientation order, the composition for forming a polarizing layer The ratio of the polymerizable liquid crystal compound (A) to the total mass of all polymerizable liquid crystal compounds contained is preferably 51 mass% or more, more preferably 70 mass% or more, and even more preferably 90 mass% or more. am.

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

The content of the polymerizable liquid crystal compound in the composition for forming a polarizing layer is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and still more preferably is 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 increase. In addition, the "solid content" herein refers to components excluding volatile components such as solvents from the composition for forming a polarizing layer, and hereinafter, when referred to as "solid content" in this specification, the same applies to solvents, etc. from the target composition. Refers to ingredients excluding volatile ingredients.

In the present invention, the composition for forming a polarizing layer that forms a polarizing layer usually contains a dichroic dye.

Here, a dichroic dye means a dye having properties where the absorbance in the major axis direction of the molecule and the absorbance in the minor axis direction are different. 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. Moreover, two or more types of 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.

As a dichroic dye, it is preferable to have a maximum absorption wavelength ( _λMAX ) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dye, oxazine dye, cyanine dye, naphthalene dye, azo dye, and anthraquinone dye.

Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakis azo dyes, and stilbenazo dyes, and bisazo dyes and trisazo dyes are preferred, for example, formula (I ) (hereinafter also referred to as “compound (I)”) represented by .

K ¹ (-N=NK ² ) _p -N=NK ³ (I)

[In formula (I), K ¹ and K ³ are independently of each other a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a benzoic acid phenyl ester group which may have a substituent, or a monovalent group which may have a substituent. Represents a heterocyclic group. K ² is a p-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, a 4,4'-stilbenylene group which may have a substituent, or a divalent heterogeneous group which may have a substituent. It represents a ring group. p represents an integer from 0 to 4. When p is an integer of 2 or more, a plurality of K ² may be the same or different from each other. In the range that shows absorption in the visible region, the -N=N- bond may be substituted with a -C=C-, -COO-, -NHCO-, or -N=CH- bond.]

Monovalent heterocyclic groups include, for example, those with one hydrogen atom removed from heterocyclic compounds such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzoimidazole, oxazole, and benzooxazole. You can raise your flag. Examples of the divalent heterocyclic group include groups obtained by removing two hydrogen atoms from the above heterocyclic compound.

phenyl group, naphthyl group, benzoic acid phenyl ester group and monovalent heterocyclic group for K ¹ and K ³ , and p-phenylene group, naphthalene-1,4-diyl group and 4,4'-steel group for K ² The substituents that the benylene group and the divalent heterocyclic group optionally have include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms having a polymerizable group, and an alkenyl group having 1 to 4 carbon atoms; Alkoxy groups having 1 to 20 carbon atoms, such as methoxy group, ethoxy group, and butoxy group; An alkoxy group having 1 to 20 carbon atoms and having a polymerizable group; fluorinated alkyl groups having 1 to 4 carbon atoms, such as trifluoromethyl group; Cyano group; nitro group; halogen atom; Substituted or unsubstituted amino groups such as amino groups, diethylamino groups, and pyrrolidino groups (a substituted amino group refers to an amino group having one or two alkyl groups having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms having a polymerizable group) Alternatively, it means an amino group in which two amino groups, or two substituted alkyl groups are 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, examples of the polymerizable group include (meth)acryloyl group and (meth)acryloyloxy group.

Among compounds (I), compounds represented by any of the following formulas (I-1) to (I-8) are preferable.

[Formula 5]

[In formulas (I-1) to (I-8),

B ¹ to B ³⁰ are each independently 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, or a substituted or unsubstituted amino group ( The definitions of substituted amino group and unsubstituted amino group are as above), chlorine atom or trifluoromethyl group.

n1 to n4 independently represent integers from 0 to 3.

When n1 is 2 or more, the plurality of B ² may be the same or different from each other,

When n2 is 2 or more, a plurality of B ⁶ may be the same or different from each other,

When n3 is 2 or more, a plurality of B ⁹ may be the same or different from each other,

When n4 is 2 or more, the plurality of B ¹⁴ may be the same or different from each other.]

As the anthraquinone dye, a compound represented by formula (I-9) is preferable.

[Formula 6]

[In 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.]

As the oxazone dye, a compound represented by formula (I-10) is preferable.

[Formula 7]

[In 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.]

As the acridine dye, a compound represented by formula (I-11) is preferable.

[Formula 8]

[In formula (I-11),

R ¹⁶ to R ²³ 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 is methyl group, ethyl group, propyl group, butyl group, pentyl group and hexyl group. and the like, and examples of the aryl group having 6 to 12 carbon atoms include phenyl group, toluyl group, xylyl group, and naphthyl group.

As the cyanine dye, a compound represented by formula (I-12) and a compound represented by formula (I-13) are preferable.

[Formula 9]

[In formula (I-12),

D ¹ and D ² independently represent a group represented by any of formulas (I-12a) to (I-12d).

[Formula 10]

n5 represents an integer from 1 to 3.]

[Formula 11]

[In formula (I-13),

D ³ and D ⁴ each independently represent a group represented by any of formulas (I-13a) to (1-13h).

[Formula 12]

n6 represents an integer from 1 to 3.]

Among these dichroic dyes, azo dyes have high linearity and are therefore preferable for producing a polarizing layer with excellent polarization performance. Therefore, in one embodiment of the present invention, the dichroic dye contained in the composition for forming a polarizing layer that forms the polarizing layer is preferably an azo dye.

In this invention, the weight average molecular weight of a dichroic dye is normally 300-2000, Preferably it is 400-1000.

In one embodiment of the present invention, the dichroic dye contained in the composition for forming a polarizing layer is preferably hydrophobic. If 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 a polarizing layer with a high degree of orientation order can be obtained. there is. In addition, in this invention, a hydrophobic dichroic dye means a dye whose solubility in 100 g of water at 25°C is 1 g or less.

The content of the dichroic dye in the composition for forming a polarizing layer can be appropriately determined depending on the type of dichroic dye used, etc., but is preferably 0.1 to 50 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. Preferably it is 0.1 to 20 parts by mass, and more preferably 0.1 to 12 parts by mass. If the content of the dichroic dye is within the above range, it is difficult to disturb the orientation of the polymerizable liquid crystal compound, and a polarizing layer with a high degree of orientation order can be obtained.

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

As the photopolymerization initiator, a known photopolymerization initiator can be used. For example, photopolymerization initiators that generate active radicals include a self-cleavage type photoinitiator and a hydrogen abstraction type photopolymerization initiator.

As a self-cleavage type photopolymerization initiator, self-cleavage type benzoin-based compounds, acetophenone-based compounds, hydroxyacetophenone-based compounds, α-aminoacetophenone-based compounds, oxime ester-based compounds, acylphosphine oxide-based compounds, A crude compound, etc. can be used. In addition, as a hydrogen abstraction type photopolymerization initiator, hydrogen abstraction type benzophenone-based compounds, benzoin ether-based compounds, benzyl ketal-based compounds, dibenzosuberone-based compounds, anthraquinone-based compounds, xanthone-based compounds, and thioxanthone-based compounds Compounds, halogenoacetophenone-based compounds, dialkoxyacetophenone-based compounds, halogenobisimidazole-based compounds, halogenotriazine-based compounds, triazine-based compounds, etc. can be used.

As photopolymerization initiators that generate acid, iodonium salts, sulfonium salts, etc. can be used.

Among these, reaction at low temperature is preferable from the viewpoint of preventing dissolution of the dye, and self-cleavage type photopolymerization initiator is preferable from the viewpoint of reaction efficiency at low temperature, especially acetophenone-based compounds and hydroxyacetophenone-based compounds. , α-aminoacetophenone-based compounds, and oxime ester-based compounds are preferred.

Specific examples of photopolymerization initiators include the following.

Benzoin-based 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-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[4 -(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexylphenylketone and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane- Hydroxyacetophenone-based compounds such as 1-one oligomers;

2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one, 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one, etc. α-aminoacetophenone-based compounds;

1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-car oxime ester-based compounds such as basol-3-yl]-,1-(O-acetyloxime); Acylphosphine oxide-based compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide;

Benzophenone, o-benzoylmethylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone and benzophenone compounds such as 2,4,6-trimethylbenzophenone;

Dialkoxyacetophenone-based 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(trichloro methyl)-6-[2-(5-methylfuran-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan- 2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1, Triazine-based compounds such as 3,5-triazine and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine. The photopolymerization initiator may be appropriately selected from the above photopolymerization initiators in relation to the polymerizable liquid crystal compound contained in the composition for forming a polarizing layer.

Additionally, you may use a commercially available photopolymerization initiator. Commercially available polymerization initiators include Irgacure (registered trademark) 907, 184, 651, 819, 250, and 369, 379, 127, 754, OXE01, OXE02, and OXE03 (manufactured by BASF); Omnirad BCIM, Esacure 1001M, Esacure KIP160 (manufactured by IDM Resins B.V.); Seikol (registered trademark) BZ, Z, and BEE (manufactured by Seiko Chemical Co., Ltd.); Kayacure (registered trademark) BP100, and UVI-6992 (manufactured by Dow Chemical Co., Ltd.); Adeka Optoma SP-152, N-1717, N-1919, SP-170, Adeka Cruise NCI-831, Adeka Cruise NCI-930 (manufactured by ADEKA Co., Ltd.); TAZ-A, and TAZ-PP (manufactured by Japan Siebel Hegner Co., Ltd.); And TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.); etc. can be mentioned.

The content of the polymerization initiator in the composition for forming a polarizing layer is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. More preferably, it is 2 to 8 parts by mass, and particularly preferably, it is 4 to 8 parts by mass. If the content of the polymerization initiator is within the above range, the polymerization reaction of the polymerizable liquid crystal compound can be performed without significantly disturbing the orientation of the polymerizable liquid crystal compound.

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

The composition for forming a polarizing layer may further contain a photosensitizer. By using a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound can be further promoted. Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone (for example, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); Anthracene compounds such as anthracene and alkoxy group-containing anthracene (for example, dibutoxyanthracene, etc.); Phenothiazine, rubrene, etc. can be mentioned. Photosensitizers can be used individually or in combination of two or more types.

When the composition for forming a polarizing layer contains a photosensitizer, its content may be appropriately determined depending on the type and amount of the polymerization initiator and the polymerizable liquid crystal compound, but is 0.1 to 30 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound. Parts by mass are preferable, 0.5 to 10 parts by mass are more preferable, and 0.5 to 8 parts by mass are still more preferable.

Moreover, the composition for forming a polarizing layer may contain a leveling agent. The leveling agent has a function of adjusting the fluidity of the composition for forming a polarizing layer and making the coating film obtained by applying the composition for forming a polarizing layer more flat, and specifically includes a surfactant. 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. The leveling agent can be used alone or in combination of two or more types.

Leveling agents containing polyacrylate compounds as a main component include, for example, "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 containing fluorine atom-containing compounds as main ingredients include, for example, “Megapak (registered trademark) R-08”, “R-30”, “R-90”, “F-410”, etc. “F-411”, “F-443”, “F-445”, “F-470”, “F-471”, “F-477”, “F-479”, “F-470” F-482” and “F-483” (DIC Co., Ltd.) ; “Suplon (registered trademark) S-381”, “S-382”, “S-383”, “S-393”, “SC-101”, “SC-105”, “KH- 40” and “SA-100” (AGC Semi Chemical Co., Ltd.) ; "E1830", "E5844" (Daikin Fine Chemical Research Institute Co., Ltd.); Examples include “Ftop EF301”, “Ftop EF303”, “Ftop EF351”, and “Ftop EF352” (Mitsubishi Material Electronics Co., Ltd.).

When the composition for forming a polarizing layer contains a leveling agent, the content is preferably 0.05 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, with respect to 100 parts by mass of the polymerizable liquid crystal compound. If the content of the leveling agent is within the above range, it is easy to orient the polymerizable liquid crystal compound, non-uniformity is less likely to occur, and a smoother polarizing layer tends to be obtained.

The composition for forming a polarizing layer may contain additives other than the photosensitizer and leveling agent. Other additives include, for example, antioxidants, mold release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When the composition for forming a polarizing layer contains other additives, the content of the other additive is preferably more than 0% and 20% by mass or less, more preferably more than 0%, with respect to the solid content of the composition for forming a polarizing layer. And it is 10% by mass or less.

The composition for forming a polarizing layer can be prepared by a conventionally known method for preparing a composition for forming a polarizing layer, and is usually mixed with a polymerizable liquid crystal compound and a dichroic dye, and, if necessary, a polymerization initiator and the above additives. It can be prepared by stirring. In addition, since compounds exhibiting smectic liquid crystallinity generally have high viscosity, from the viewpoint of improving the applicability of the composition for forming a polarizing layer and facilitating the formation of the polarizing layer, the viscosity is increased by adding a solvent to the composition for forming a polarizing layer. Adjustments may be made.

The solvent used in the composition for forming a polarizing layer can be appropriately selected depending on 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, Ester solvents such as ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, and methyl isobutyl ketone Solvents, aliphatic hydrocarbon solvents such as pentane, hexane, and heptane, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorination such as chloroform and chlorobenzene. Hydrocarbon solvents, etc. can be mentioned. These solvents can be used individually or in combination of two or more types. The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and even more preferably 180 to 600 parts by mass, based on 100 parts by mass of solid content of the composition for forming a polarizing layer.

In the present invention, it is preferable that the polarizing layer is a polarizer with a high degree of orientation order. For a polarizer with a high degree of orientation order, a Bragg peak derived from a higher-order structure such as a hexatic phase or a crystal phase is obtained in an X-ray diffraction measurement. Bragg peak refers to a peak derived from the plane periodic structure of molecular orientation. Therefore, it is preferable that the polarizing layer constituting the optical laminate of the present invention 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 and absorbs light. It is more preferable that the molecules of the polymerizable liquid crystal compound are oriented in a “horizontal orientation”. In the present invention, a polarizer whose plane periodic interval of molecular orientation is 3.0 to 6.0 Å is preferable. A high degree of alignment order showing a Bragg peak can be realized by controlling the type of polymerizable liquid crystal compound used, the type and amount of dichroic dye, and the type and amount of polymerization initiator.

In the present invention, the polarizing layer is, for example, formed by forming a coating film of a composition for forming a polarizing layer on a substrate or an orientation film described later, removing a solvent from the coating film, and temperature at which the polymerizable liquid crystal compound undergoes a phase transition to the liquid phase. It can be obtained by a method including raising the temperature to the above level, lowering the temperature, causing a 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.

Methods for applying the composition for forming a polarizing layer to a substrate or alignment film include, for example, spin coating, extrusion, gravure coating, die coating, bar coating, applicator coating, flexo, etc. Known methods such as the printing method may be mentioned.

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

Additionally, in order to phase transfer the polymerizable liquid crystal compound to a liquid phase, the temperature is raised to a temperature higher than that at which the polymerizable liquid crystal compound undergoes a phase transition to a liquid phase, and then the temperature is lowered, and the polymerizable liquid crystal compound is phase transferred to a liquid crystal phase (smectic phase). This phase transition may be performed after removal of the solvent in the coating film, or may be performed simultaneously with removal of the solvent.

By polymerizing the polymerizable liquid crystal compound while maintaining its liquid crystal state, a polarizing layer is formed as a cured product of the composition for forming a polarizing layer. As a polymerization method, photopolymerization is preferred. In photopolymerization, the light irradiated to the dry coating film includes the type of polymerizable liquid crystal compound contained in the dry coating film (in particular, the type of polymerizable group that the polymerizable liquid crystal compound has), the type of polymerization initiator, and their amounts. It is appropriately selected depending on the etc. Specific examples include one or more types of light or active electron beams selected from the group consisting of visible light, ultraviolet light, infrared light, X-ray, α-ray, β-ray, and γ-ray. Among them, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and because it is possible to use a photopolymerization device that is widely used in the field, and a polarizing layer is used to enable photopolymerization by ultraviolet light. It is desirable to select the type of polymerizable liquid crystal compound or polymerization initiator contained in the forming composition. Additionally, the polymerization temperature can also be controlled by irradiating the dried coating film with light while cooling it using an appropriate cooling means during polymerization. A patterned polarizing layer can also be obtained by performing masking or development during photopolymerization.

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

The ultraviolet irradiation intensity is usually 10 to 3,000 mW/cm2. The ultraviolet irradiation intensity is preferably an intensity in the wavelength range effective for activation of the photopolymerization initiator. The time for irradiating light is usually 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and even more preferably 10 seconds to 1 minute. When irradiated with such ultraviolet irradiation intensity once or multiple times, the accumulated light amount is 10 to 3,000 mJ/cm2, preferably 50 to 2,000 mJ/cm2, and more preferably 100 to 1,000 mJ/cm2.

By performing photopolymerization, the polymerizable liquid crystal compound polymerizes while maintaining the liquid crystal state of a liquid crystal phase, especially a smectic phase, preferably a high-order smectic phase, and a polarizing layer is formed. A polarizing layer obtained by polymerizing a polymerizable liquid crystal compound while maintaining the smectic liquid crystal state is also accompanied by the action of the dichroic dye, and is similar to a conventional host-guest type polarizing film, that is, a polarizing layer in the nematic liquid crystal state. Compared to , it has the advantage of high polarization performance. Additionally, there is an advantage of superior strength compared to applying only dichroic dyes or lyotropic liquid crystals.

The thickness of the polarizing layer can be appropriately selected depending on the display device to be applied, and is preferably 0.1 to 5 μm, more preferably 0.3 to 4 μm, and still more preferably 0.5 to 3 μm. If the film thickness of the polarizing layer is more than the above lower limit, it is easy to prevent the necessary light absorption from being unable to be obtained, and if it is less than the above upper limit, it is easy to suppress the occurrence of orientation defects due to a decrease in the orientation regularization force caused by the alignment film.

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

A 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 also referred to as “composition for forming a photo-alignment film”). It is obtained by applying it on a substrate or, if necessary, a diffusion prevention layer formed on the substrate, and irradiating polarized light (preferably polarized UV). The substrate on which the photo-alignment film type is formed includes the same substrate as the substrate film of the optical laminate of the present invention. If the polymer contained in the composition for forming a photo-alignment film has a reactive group (for example, a (meth)acryloyl group) that is the same as the functional group of the polymerizable group of the polymerizable liquid crystal compound forming the polarizing layer, the polarizing layer and Adhesion between the tends to improve.

A photoreactive group refers to a group that generates liquid crystal alignment ability by irradiating light. Specifically, groups involved in photoreactions that cause orientation of molecules generated by light irradiation or are the origin of liquid crystal alignment ability, such as isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction, can be mentioned. Among these, groups involved in dimerization reactions or photo-crosslinking reactions are preferable because they have excellent orientation. As the photoreactive group, groups having an unsaturated bond, especially a double bond, are preferred, such as a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N A group having at least one selected from the group consisting of a carbon-oxygen double bond (C=O bond) and a carbon-oxygen double bond (C=O bond) is particularly preferred.

Photoreactive groups having a C=C bond include vinyl group, polyene group, stilbene group, stilbazol group, stilbazolium group, chalcone group, and cinnamoyl group. Examples of the photoreactive group having a C=N bond include groups having structures such as aromatic Schiff base and aromatic hydrazone. Examples of the photoreactive group having an N=N bond include an azobenzene group, azonaphthalene group, aromatic heterocyclic azo group, bisazo group, forma residue group, and group having an azoxybenzene structure. Examples of photoreactive groups having a C=O bond include benzophenone group, coumarin group, anthraquinone group, and maleimide group. These groups may have substituents such as an alkyl group, alkoxy group, aryl group, allyloxy group, cyano group, alkoxycarbonyl group, hydroxyl group, sulfonic acid group, and halogenated alkyl group.

Among them, the photoreactive group involved in the photodimerization reaction is preferable, and the amount of polarized light irradiation required for photoalignment is relatively small, and a photoalignment film with excellent thermal stability and stability over time is easy to obtain, so cinnamoyl group and chalcone group. desirable. As a polymer or the like having a photoreactive group, one having a cinnamoyl group whose terminal portion of the polymer side chain has a cinnamic acid structure is particularly preferable.

A photo-alignment layer can be formed by applying the composition for forming a photo-alignment layer, for example, onto a substrate or a diffusion prevention layer formed on the substrate. Solvents contained in the composition include the same solvents as those previously exemplified as solvents that can be used when forming the polarizing layer, and can be appropriately selected depending on the solubility of the polymer or the like having a photoreactive group.

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

Methods of applying a composition for forming a photo-alignment layer on a substrate or a diffusion prevention layer, and methods of removing a solvent from the applied composition for forming a photo-alignment layer include a method of applying the composition for forming a polarizing layer to a substrate, etc., and a method of removing the solvent. The same method as the method may be mentioned.

Irradiation of polarized light may be in the form of irradiating polarized UV directly onto a coating film of the composition for forming a photo-alignment film from which the solvent has been removed, 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 the polarized light to be irradiated is preferably in a wavelength range where 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 preferable. Light sources used for the polarization irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps. is more preferable. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because they have a high emission intensity of ultraviolet rays with a wavelength of 313 nm. Polarized UV can be irradiated by passing the light from the light source through an appropriate polarizer and irradiating it. As such a polarizer, a polarizing filter, a polarizing prism such as Glenn Thompson or Glenn Taylor, or a wire grid type polarizer can be used.

In addition, when performing polarized light irradiation, if masking is performed, a plurality of regions (patterns) with different directions of liquid crystal orientation can be formed.

The number average molecular weight of the photo-alignment film is preferably 20,000 to 100,000, more preferably 25,000 or more, and even more preferably 90,000 or less, and even more preferably 80,000 or less. If the number average molecular weight of the photo-alignment film is within the above range, adhesion to the layer adjacent to the photo-alignment film is likely to improve. The number average molecular weight of the photo-alignment film can be controlled by the amount of monomer used in the composition for forming a photo-alignment film, the type and amount of the polymerization initiator, etc.

In addition, the "number average molecular weight of the photo-alignment film" referred to 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 a gel permeation chromatography. It is the molecular weight calculated by measuring itself.

The thickness of the photo-alignment film is preferably 10 to 5000 nm, more preferably 10 to 1000 nm, and still more preferably 30 to 300 nm. If the thickness of the photo-alignment film is within the above range, an alignment regularization force can be exerted while exhibiting good adhesion at the interface with the polarizing layer, and a 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 relief layer and the polarizing layer. By the presence of a diffusion prevention layer between the first stress relief layer and the polarizing layer, diffusion of the dichroic dye in the polarizing layer to other layers can be effectively suppressed, and when the optical laminate of the present invention is mounted on a display device, etc. Deterioration of optical properties over time resulting from diffusion of dichroic dyes can be suppressed. From the viewpoint of sufficiently obtaining this effect, the diffusion prevention layer is preferably formed adjacent to the polarizing layer on the first stress relieving layer side of the polarizing layer, and the polarizing layer is formed on both the first stress relieving layer side and the retardation layer side of the polarizing layer, respectively. It is more preferable that it is adjacent to or is formed through only the alignment film that forms the polarizing layer. When the diffusion prevention layer is formed on both the first stress relief 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 that has the function of preventing the diffusion of the dichroic dye. For example, a layer formed from a resin composition containing a water-soluble polymer, and a layer formed from a curable composition containing an active energy ray curable resin. layers, etc. can be mentioned.

Because the polarity of water-soluble polymers is significantly different from that of dichroic dyes, they may hinder the diffusion of dichroic dyes. Examples of water-soluble polymers that can form a diffusion prevention layer include polyacrylamide-based polymers; Vinyl alcohol-based polymers such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, (meth)acrylic acid or its anhydride-vinyl alcohol copolymer; Carboxyvinyl-based polymer; polyvinylpyrrolidone; All classifications; Sodium alginate; Or a polyethylene oxide-based polymer, etc. can be mentioned. These polymers may be used individually, or may be used in combination of two or more types.

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

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

When a cross-linking agent is used to introduce a cross-linking structure into the diffusion prevention layer, the amount added may be appropriately determined depending on the type of cross-linking agent used. For example, the amount may be 0.1 to 100 parts by mass, preferably 1 to 50 parts by mass, more preferably 10 to 30 parts by mass, based on 100 parts by mass of the water-soluble polymer. If the content of the crosslinking agent is within the above range, the diffusion prevention layer becomes dense, and the shielding effect against the dichroic dye in the light-absorbing anisotropic film is likely to improve.

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 depending on the water-soluble polymer to be used, and typically include water, alcohol, and a mixture of water and alcohol, 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 water-soluble polymer and crosslinking agent, is preferably 1 to 50 mass%, more preferably 2 to 30 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 lowered, and coatability and handleability become good.

The water-soluble polymer-containing resin composition may contain other components such as additives in addition to the water-soluble polymer, crosslinking agent, and solvent such as water. Other such 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 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 anti-diffusion layer can be obtained by coating a water-soluble polymer-containing resin composition on the surface where the anti-diffusion layer is to be formed, drying and hardening the coating film.

The method for applying the water-soluble polymer-containing resin composition is not particularly limited, and includes known methods similar to those for applying the composition for forming a polarizing layer to a substrate or the like.

The drying temperature or time for forming the diffusion prevention layer from the coating film of the water-soluble polymer-containing resin composition is not particularly limited and may be appropriately determined depending on the composition of the water-soluble polymer-containing resin composition to be used. Drying treatment can be performed, for example, by spraying hot air, and the temperature is usually in the range of 40 to 100°C, preferably 60 to 100°C. Additionally, the drying time is usually 10 to 600 seconds.

Since active energy ray-curable resins can be highly polymerized, they tend to have an excellent function of preventing the diffusion of dichroic dyes. The curable composition containing an active energy ray-curable resin capable of forming an anti-diffusion layer (hereinafter also referred to as “curable composition for forming an anti-diffusion layer”) includes a cationically polymerizable curable composition containing a cationically polymerizable compound as a curable compound. composition, a radically polymerizable curable composition containing a radically polymerizable compound as the curable compound, and a hybrid type curable composition containing both a cationically polymerizable compound and a radically polymerizable compound. Specific examples of cationically 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. In addition, specific examples of radically polymerizable compounds include (meth)acrylic compounds and vinyl compounds having one or more (meth)acryloyl groups in the molecule. The curable composition for forming a diffusion prevention layer may contain one or two or more types of cationically polymerizable compounds, and/or may contain one or two or more types of radically polymerizable compounds.

A cationically polymerizable compound, which is the main component of a cationically polymerizable type curable composition, refers to a compound or oligomer that undergoes a cationic polymerization reaction and hardens when irradiated or heated with active energy rays such as ultraviolet rays, visible light, electron beams, or X-rays. , epoxy compounds, oxetane compounds, vinyl compounds, etc. can be exemplified. Among them, a preferable cationically polymerizable compound is an epoxy compound.

An epoxy compound is a compound having one or more, preferably two or more, epoxy groups in the molecule. Epoxy compounds may be used individually as one type, or may be used in combination of two or more types. Examples of the epoxy compound include alicyclic epoxy compounds, aromatic epoxy compounds, hydrogenated epoxy compounds, and aliphatic epoxy compounds. Among them, from the viewpoint of weather resistance, curing speed, and adhesiveness, it is preferable that the epoxy compound contains an alicyclic epoxy compound or an aliphatic epoxy compound.

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 preferably 10 parts by mass based on 100 parts by mass of solid content of the curable composition. parts or more, more preferably 15 parts by mass or more, further 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 the curable compound contained in the curable composition for forming a diffusion prevention layer containing a cationically polymerizable compound (including the case of a hybrid type) is 100% by mass, the content of the cationically polymerizable compound (two or more types The total content (when cationically polymerizable compounds are included) is preferably 50 mass% or more, more preferably 60 mass% or more, and even more preferably 70 mass% or more. In addition, the cationic polymerization type curable composition may further contain a polymer component (such as a thermoplastic resin).

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

Photocationic polymerization initiators may be used individually as one type or may be used in combination of two or more types. Among them, aromatic sulfonium salts are preferably used because they have ultraviolet absorption characteristics even in the wavelength range around 300 nm, are excellent in curability, and can provide a cured product with good mechanical and adhesive strength.

The content of the photocationic polymerization initiator in the curable composition for forming a diffusion prevention layer 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. If the content of the photocationic polymerization initiator is within the above range, the cationically polymerizable compound can be sufficiently cured, and high mechanical strength and adhesive strength can be provided to the resulting diffusion prevention layer.

The cationically polymerizable curable composition can also be made into a hybrid type curable composition by containing a radically polymerizable compound in addition to the cationically polymerizable compound. By using a radically polymerizable compound in combination, the effect of increasing the hardness and mechanical strength of the diffusion prevention layer can be expected, and furthermore, it becomes easier to adjust the viscosity, curing speed, etc. of the curable composition.

A radically polymerizable compound, which is the main component of a radically polymerizable curable composition, refers to a compound or oligomer that undergoes a radical polymerization reaction and hardens by irradiation or heating of active energy rays such as ultraviolet rays, visible light, electron beams, or X-rays. includes compounds 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-2-pyrrolidone. Vinyl compounds such as these can be mentioned. Among them, preferable radically polymerizable compounds are (meth)acrylic compounds.

A (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 the (meth)acrylate compound 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, etc. can be mentioned. As for the (meth)acrylic compound, only 1 type may be used individually, or 2 or more types may be used together.

(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 can be mentioned.

When using a polyfunctional (meth)acrylate compound, the crosslinking density of the diffusion prevention layer can be adjusted by controlling the molecular weight and number of crosslinking points between crosslinking points of the compound. More specifically, as the molecular weight between crosslinking points decreases, the crosslinking density increases, and as the number of crosslinking points increases, the crosslinking density becomes denser, thereby improving the shielding ability against the dichroic dye in the light-absorbing anisotropic film.

A urethane (meth)acrylate compound generally refers to a reaction product of an isocyanate compound, a polyol compound, and a (meth)acrylate compound, and is a polyfunctional urethane (meth) having two or more (meth)acryloyloxy groups in the molecule. It is preferable that it is an acrylate compound. 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 to 5.

The epoxy (meth)acrylate compound is, for example, a polyfunctional epoxy that can be obtained by the addition reaction of polyglycidyl ether and (meth)acrylic acid and has at least two (meth)acryloyloxy groups in the molecule. (meth)acrylate, etc. can be mentioned.

Examples of polyester (meth)acrylate compounds include 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 curable composition for forming a diffusion prevention layer contains a radically polymerizable compound, it is preferable to include 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 even more preferably 70 parts by mass or more, based on 100 parts by mass of the solid content of the curable composition. and is 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.

Additionally, in one embodiment of the present invention, when the curable composition for forming a diffusion prevention layer contains a radically polymerizable compound, a polyfunctional (meth)acrylate compound and a polyfunctional urethane (meth)acrylate compound are used as the radically polymerizable compound. It is desirable to include it. 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). ) Acrylate compound: It is preferable to include urethane (meth)acrylate compound, mass ratio).

When the curable composition for forming a diffusion prevention layer contains a radically polymerizable compound, it is preferable to contain a radical photopolymerization initiator. A radical photopolymerization initiator initiates the polymerization reaction of a radically curable compound by irradiation of active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams. The radical photopolymerization initiator may be used individually as one type or may be used in combination of two or more types.

Specific examples of radical photopolymerization initiators include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, and 2-methyl. Acetophenone-based initiators such as -1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; Benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone; Alkylphenone initiators such as 2,2-dimethoxy-1,2-diphenylethan-1-one and 1-hydroxy-cyclohexyl-phenyl-ketone; Benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; Thioxanthone-based initiators such as 4-isopropylthioxanthone; Acylphosphine oxide-based initiators such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; In addition, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone, etc. can be mentioned.

The content of the radical photopolymerization initiator in the curable composition for forming a diffusion prevention layer 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. If the content of the radical photopolymerization initiator is within the above range, the polymerization initiation ability is sufficiently expressed, curability is improved, and it becomes difficult for the radical photopolymerization initiator to remain, making it easy to suppress a decrease in visible light transmittance, etc.

In the present invention, the curable composition for forming a diffusion prevention layer may contain an organic solvent to adjust the viscosity to a viscosity suitable for the coating method employed, for example, or may be substantially solvent-free (solvent-free). In addition, “substantially not included” means that the case where solvent is inevitably mixed is not excluded.

The solvent may be any solvent that can dissolve the components constituting the diffusion prevention layer, and examples of the solvent are the same as those that can be used in the composition for forming a polarizing layer. These solvents may be used individually, or may be used in combination of two or more types.

The type and content of the solvent are appropriately selected depending on the type, content, shape, application method, thickness of the diffusion prevention layer, etc. of the components constituting the diffusion prevention layer. When a solvent is included, the amount is, for example, preferably 3 to 1000 parts by mass, more preferably 5 to 100 parts by mass, and even more preferably 7 to 50 parts by mass, based on 100 parts by mass of solid content of the curable composition. It is wealth.

The curable composition for forming an anti-diffusion layer may, if necessary, 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 regulator, a plasticizer, an antifoaming agent, an antistatic agent, It may contain additives such as a leveling agent.

For example, a diffusion prevention layer can be obtained by coating a curable composition for forming a diffusion prevention layer on the surface where the diffusion prevention layer is to be formed, irradiating the coating film with active energy rays, and curing the composition. As for the method of applying the curable composition for forming the anti-diffusion layer, the type of active energy ray used for curing, the light source, the irradiation conditions, etc., the same methods and conditions as the method of applying and curing the composition for forming the polarizing layer can be adopted. You can.

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 further preferably 0.5 μm or more and 3 μm or less. If it is within the above range, diffusion of the dichroic dye in the polarizing layer to other layers can be effectively suppressed. When the anti-diffusion layer is included on both the first stress relief layer side and the retardation layer side of the polarizing layer, its thickness may be the same or different.

[Phase difference layer]

The retardation layer included in the optical laminate of the present invention is a layer that expresses retardation. From the viewpoint of reducing the thickness of the optical laminate, the retardation layer is preferably a coating layer, and more preferably consists of a cured layer of a polymerizable liquid crystal composition containing at least one type of polymerizable liquid crystal compound. The optical laminate of the present invention is excellent in the effect of suppressing the occurrence of misalignment, wrinkles, etc. when the two outer layer surfaces revealed by peeling the first base film and the second base film are respectively transferred and mounted on a display device. Therefore, a high circular polarization function can be expected even after mounting on a display device, etc. by double-sided transfer. In the optical laminate of the present invention, the number of retardation layers may be one, or two or more may be included.

The optical laminate of the present invention preferably includes a retardation layer that satisfies the following formula (3).

120 ㎚ ≤ Re(550) ≤ 170 ㎚ (3)

[In the equation, Re(λ) represents the in-plane retardation value of the retardation layer at the wavelength λ nm.]

If the in-plane retardation Re(550) of the retardation layer is within the range of equation (3), the retardation layer becomes a retardation layer that functions as a 1/4 wave plate, and an optical laminate (circular polarizer) containing the retardation layer is formed. When applied to an organic EL display device, etc., the effect of improving the front reflected color (effect of suppressing coloring) is likely 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 that satisfies the above 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 the in-plane retardation value of the retardation layer at the wavelength λ nm.]

When the retardation layer satisfies equations (4) and (5), the retardation layer exhibits so-called reverse wavelength dispersion, in which the in-plane retardation value at a short wavelength becomes smaller than the in-plane retardation value at a long wavelength. An optical laminate (circular polarizer) having such a phase contrast layer tends to have excellent front color when mounted on an organic EL display device or the like. From the viewpoint of improving reverse wavelength dispersion and further enhancing the effect of improving the reflection color in the front direction, Re(450)/Re(550) is preferably 0.70 or more, more preferably 0.78 or more, and , preferably 0.92 or less, more preferably 0.90 or less, further preferably 0.87 or less, particularly preferably 0.86 or less, and more particularly preferably 0.85 or less. Moreover, 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 equation Re(λ) = (nx(λ) - ny(λ)) × d, the desired in-plane retardation value (Re(λ): retardation layer at wavelength λ (nm) In order to obtain the in-plane retardation value of , the three-dimensional refractive index and film thickness d can be adjusted. In addition, in the above formula, d represents the thickness of the target retardation layer, and nx is the main refractive index 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. represents the refractive index ellipsoid formed by the retardation layer, and ny represents the refractive index at a wavelength λ nm in a direction parallel to the plane of the retardation layer and orthogonal to the direction of nx.

The optical laminate of the present invention preferably includes a retardation layer made of a “horizontally aligned liquid crystal cured layer” cured in a state where the polymerizable liquid crystal compound is oriented horizontally with respect to the substrate surface, and the above formula (3) - It is more preferable to include a horizontally aligned liquid crystal cured layer that satisfies (5). When the optical laminate of the present invention includes one retardation layer, the retardation layer constituting the retardation layer is usually a “horizontal alignment liquid crystal cured layer.”

In addition to the retardation layer that is 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. The liquid crystal cured 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 aligned perpendicular to the substrate surface. By including a combination of a retardation layer, which is a horizontally aligned liquid crystal cured layer, and a retardation layer, which is a vertically aligned liquid crystal cured layer, when the optical laminate is applied to an organic EL display device, etc., in addition to improving the front reflected color, the color reflected from all directions is also improved. You can expect it. 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 disposed 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, it is preferable that the liquid crystal cured layer satisfies the formula (6).

-100 ㎚ ≤ Rth(550) ≤ -40 ㎚ (6)

[In the formula, Rth(550) represents the phase difference value in the thickness direction of the liquid crystal cured layer at a wavelength of 550 nm, and Rth = ((nx(λ) + ny(λ))/2 - nz) × d ( d represents the thickness of the liquid crystal cured layer, nx represents the main refractive index at the wavelength λ nm 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. In the refractive index ellipsoid formed by the layer, it represents the refractive index at a wavelength λ nm in a direction parallel to the plane of the liquid crystal cured layer and orthogonal to the direction of nx, and nz is the index formed by the liquid crystal cured layer. In the refractive index ellipsoid, it represents the refractive index at the wavelength λ nm in the direction perpendicular to the plane of the liquid crystal hardening layer.]

When the vertically aligned liquid crystal cured layer satisfies equation (6), the omnidirectional reflection color can be improved when an optical laminate (circular polarizer) containing the liquid crystal cured layer is applied to an organic EL display device. The retardation value Rth (550) of the liquid crystal cured layer in the film thickness direction is more preferably -90 nm or more, further preferably -80 nm or more, and even more preferably -50 nm or less.

In the present invention, the retardation layer (horizontally aligned liquid crystal cured layer and vertically aligned liquid crystal cured layer) is a polymerizable liquid crystal composition (hereinafter also referred to as “composition for forming a retardation layer”) containing at least one type of polymerizable liquid crystal compound. It consists of a hardened layer. The polymerizable liquid crystal compound may be appropriately selected from polymerizable liquid crystal compounds conventionally known in the field of retardation films, depending on the desired optical properties.

A polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. The polymerizable liquid crystal compound generally includes a polymer (cured product) obtained by polymerizing the polymerizable liquid crystal compound alone while oriented in a specific direction, and a polymerizable liquid crystal compound exhibiting forward wavelength dispersion and reverse wavelength dispersion. A polymerizable liquid crystal compound representing . In the present invention, only one type of polymerizable liquid crystal compound may be used, or a mixture of both types of polymerizable liquid crystal compounds may be used.

Additionally, 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 them may be the same or different from each other. From the viewpoint of easily improving the optical properties as an 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. It is desirable to be

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

The liquid crystallinity exhibited by the polymerizable liquid crystal compound may be thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferable because it allows precise film thickness control. Additionally, the phase order structure in the thermotropic liquid crystal may be nematic liquid crystal, smectic liquid crystal, or discotic liquid crystal. The polymerizable liquid crystal compound can be used alone or in combination of two or more types.

Polymerizable liquid crystal compounds with a so-called T-shaped or H-type molecular structure tend to exhibit reverse wavelength dispersion when polymerized and cured, and polymerizable liquid crystal compounds with a T-shaped molecular structure exhibit stronger reverse wavelength dispersion. tends to emerge.

The polymerizable liquid crystal compound exhibiting reverse wavelength dispersion is preferably a compound having the following characteristics (A) to (D).

(A) It is a compound that can form a nematic phase or smectic phase.

(B) The polymerizable liquid crystal compound has π electrons in the long axis direction (a).

(C) It has π electrons in the direction crossing the major axis direction (a) [crossing direction (b)].

(D) The long axis of the polymerizable liquid crystal compound defined by the following formula (i), with the sum of π electrons existing in the long axis direction (a) being N(πa) and the sum of molecular weights existing in the long axis direction being N(Aa). π electron density in direction (a):

D(πa) = N(πa)/N(Aa) (i)

and the sum of π electrons existing in the crossing direction (b) is N(πb), and the sum of molecular weights existing in the crossing direction (b) is N(Ab). A polymerizable liquid crystal defined in the formula (ii) below. π electron density in the cross direction (b) of the compound:

D(πb) = N(πb)/N(Ab) (ii)

A, Equation (iii)

0 ≤ 〔D(πa)/D(πb)〕＜ 1 (iii)

There is a relationship [that is, the π electron density in the cross direction (b) is greater than the π electron density in the major axis direction (a)]. As described above, a polymerizable liquid crystal compound having π electrons on the long axis and in a direction crossing thereto generally tends to have a T-shaped structure.

In the above features (A) to (D), 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 the rod shape if it is a compound having a rod-shaped structure.

· The number of π electrons N(πa) present in the long axis direction (a) does not include π electrons lost through polymerization reaction.

・The number of π electrons N(πa) existing on the long axis direction (a) is the total number of π electrons on the long axis and π electrons conjugated thereto, for example, as a ring existing on the long axis direction (a) , the number of π electrons present in the ring that satisfies Hückel's law is included.

· The number of π electrons N(πb) present in the crossing direction (b) does not include π electrons lost through the polymerization reaction.

The polymerizable liquid crystal compound that satisfies the above has a mesogenic structure in the major axis direction. This mesogenic structure produces a liquid crystalline phase (nematic phase, smectic phase).

It is possible to form a nematic phase or smectic phase by heating the 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 compounds, the major axes of the polymerizable liquid crystal compounds are generally oriented parallel to each other, and this major axis direction becomes the orientation direction of the nematic phase or smectic phase. When such a polymerizable liquid crystal compound is formed into a film and polymerized in a nematic or smectic phase, a polymer film composed of the polymer polymerized in a state oriented in the major axis direction (a) can be formed. This polymer film absorbs ultraviolet rays by π electrons in the major axis direction (a) and π electrons in the cross direction (b). Here, the maximum absorption wavelength of ultraviolet rays absorbed by π electrons in the crossing direction (b) is called λbmax. λbmax is usually 300 nm to 400 nm. The density of π electrons satisfies the above formula (iii), and since the π electron density in the crossing direction (b) is greater than the π electron density in the major axis direction (a), linearly polarized light having a vibration plane in the crossing direction (b) The polymer film has a greater absorption of ultraviolet rays (wavelength: λbmax) than absorption of linearly polarized ultraviolet rays (wavelength: λbmax) that has a vibration plane in the major axis direction (a). The ratio (ratio of absorbance in the crossing direction (b) of linearly polarized ultraviolet rays/absorbance in the major axis direction (a)) is, for example, greater than 1.0, preferably 1.2 or more, usually 30 or less, for example 10 or less. am.

In general, polymerizable liquid crystal compounds having the above characteristics often exhibit reverse wavelength dispersion in their birefringence when polymerized in a unidirectional state. Specifically, for example, a compound represented by the following formula (X) (hereinafter also referred to as “polymerizable liquid crystal compound (X)”) can be mentioned.

[Formula 13]

In formula (X), Ar represents a divalent group having an aromatic group that may have a substituent. The aromatic group referred to herein includes, for example, groups exemplified by (Ar-1) to (Ar-23) described later. Additionally, Ar may have two or more aromatic groups. The aromatic group may contain at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. When there are two or more aromatic groups contained in Ar, the two or more aromatic groups may be bonded to each other through a single bond or a divalent bonding group such as -CO-O- or -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 with 1 to 4 carbon atoms, a fluoroalkyl group with 1 to 4 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, a cyano group, or It may be substituted with a nitro group, and the 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.

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

In formula (X), k and l each independently represent an integer from 0 to 3 and satisfy the relationship of 1 ≤ k + l. Here, when 2 ≤ k + l, B ¹ and B ² , 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, and an alkanediyl group having 4 to 12 carbon atoms is more preferable. In addition, the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O-, -S-, or -C(=O)-. You can stay.

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

G ¹ and G ² are each independently, preferably a 1,4-phenylenediyl group, a halogen atom, and It is a 1,4-cyclohexanediyl group which may be substituted with at least one substituent selected from the group consisting of alkyl groups having 1 to 4 carbon atoms, more preferably a 1,4-phenylenediyl group substituted with a methyl group, or an unsubstituted group. 1,4-phenylenediyl group, or unsubstituted 1,4-trans-cyclohexanediyl group, especially preferably unsubstituted 1,4-phenylenediyl group, or unsubstituted 1,4-trans-cyclo It is a hexanediyl group.

In addition, it is preferable that at least one of the plurality of G ¹ and G ² is a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² is a divalent alicyclic hydrocarbon group. It is more preferable that it is

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 or a hydrogen atom having 1 to 4 carbon atoms. 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 - am. 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 - am. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent a single bond, -CH ₂ -, -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 - am.

From the viewpoint of developing reverse wavelength dispersion, k and l are preferably in the range of 2 ≤ k + l ≤ 6, preferably k + l = 4, and more preferably k = 2 and l = 2. k = 2 and l = 2 are also desirable because it results in a 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 oxeta. Nil group, etc. can be mentioned. Among them, (meth)acryloyl group, vinyl group, and vinyloxy group are preferable, and (meth)acryloyl group is more preferable.

Ar preferably has at least one selected from the group consisting of an aromatic hydrocarbon ring that may have a substituent, an aromatic heterocycle that may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and anthracene ring, with a benzene ring and a naphthalene ring being preferred. The aromatic heterocyclic ring includes a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, and a pyrroline ring. , an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Among them, those having a thiazole ring, a benzothiazole ring, or a benzofuran ring are preferable, and those having a benzothiazole ring are more preferable. Additionally, when Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

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, further preferably 14 or more, and especially preferably is 16 or more. Moreover, it is preferably 36 or less, more preferably 32 or less, further preferably 26 or less, and especially preferably 24 or less.

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

[Formula 14]

In formulas (Ar-1) to (Ar-23), * represents a connecting portion, and Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or No group, nitro group, alkylsulfinyl group with 1 to 12 carbon atoms, alkylsulfonyl group with 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group with 1 to 12 carbon atoms, alkoxy group with 1 to 12 carbon atoms, alkylthio group with 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 N,N-dialkylsulfamoyl group having 2 to 12 carbon atoms. represents. Additionally, 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' -, - CO- or -O- is represented, 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 from 0 to 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, and phenyl group and naphthyl group are preferred, and a phenyl group is more preferred. The aromatic heterocyclic group includes at least one heteroatom such as a nitrogen atom such as a furyl group, pyrrolyl group, thienyl group, pyridinyl group, thiazolyl group, and benzothiazolyl group, an oxygen atom, and a sulfur atom, and has 4 to 4 carbon atoms. Examples of aromatic heterocyclic groups of 20 include furyl group, thienyl group, pyridinyl group, thiazolyl group, and benzothiazolyl group.

Y ¹ , Y ² and Y ³ may each independently be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group that may be substituted. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from a set of aromatic rings. The polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from a set of aromatic rings.

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

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 bonded and Z ⁰ . Examples of the aromatic heterocyclic ring group include the aromatic heterocyclic rings that Ar may have, and examples include pyrrole ring, imidazole ring, pyrroline ring, pyridine ring, pyrazine ring, pyrimidine ring, indole ring, A quinoline ring, an isoquinoline ring, a purine ring, a pyrrolidine ring, etc. can be mentioned. This aromatic heterocyclic group may have a substituent. Additionally, Y ¹ , together with the nitrogen atom to which it is bonded and Z ⁰ , may be the polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group that may be substituted as described above. For example, a benzofuran ring, a benzothiazole ring, a benzoxazole ring, etc. can be mentioned.

The compound represented by formula (X) can be produced, for example, according to the method described in Japanese Patent Application Publication No. 2010-31223.

As the polymerizable liquid crystal compound forming the phase contrast 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 constant wavelength dispersion. These polymerizable liquid crystal compounds can be used individually or in combination of two or more types.

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-, - CS- represents a single bond. R ¹⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

B12 and B13 are each independently -C≡C-, -CH=CH-, -CH ₂ -CH ₂ -, -O-, -S-, -C(=O)-, -C(=O )-O-, -OC(=O)-, -OC(=O)-O-, -CH=N-, -N=CH-, -N=N-, -C(=O)-NR ¹⁶ -, -NR ¹⁶ -C(=O)-, -OCH ₂ -, -OCF ₂ -, -CH ₂ O-, -CF ₂ O-, -CH=CH-C(=O)-O-, - OC(=O)-CH=CH-, -H, -C≡N or represents a single bond.

E11 represents an alkanediyl group having 1 to 12 carbon atoms, and 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. You can stay. Additionally, -CH ₂ - constituting the alkanediyl group may be substituted with -O- or -CO-.]

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

As E11, a linear alkanediyl group having 1 to 12 carbon atoms is preferable. -CH ₂ - constituting the alkanediyl group may be substituted 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-diyl group. 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.

As B11, -O-, -S-, -CO-O-, and -O-CO- are preferable, and among them, -CO-O- is more preferable.

As B12 and B13, each independently -O-, -S-, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -O-C(=O) -O- is preferable, and among these, -O- or -O-C(=O)-O- is more preferable.

The polymerizable group represented by P11 is preferably a radical polymerizable group or a cationic polymerizable group because of its high polymerization reactivity, especially photopolymerization reactivity, and because it is easy to handle and the production of the liquid crystal compound itself is easy. The base group is preferably a group represented by the following formulas (P-11) to (P-15).

[Formula 15]

[In 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 groups represented by formulas (P-11) to (P-15) include groups represented by the following formulas (P-16) to (P-20).

[Formula 16]

P11 is preferably a group represented by formulas (P-14) to (P-20), and more preferably a vinyl group, p-stilbene group, epoxy group, or oxetanyl group.

It is more preferable that 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)

[During the ceremony,

A11, B11 to B13 and P11 have the same meaning as above,

A12 to A14 each independently have the same meaning as A11, B14 to B16 each independently have the same meaning as B12, B17 has the same meaning as B11, E12 has the same meaning as E11, and P12 has the same meaning as P11. am.

F11 is a hydrogen atom, an alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, cyano group, nitro group, trifluoromethyl group, dimethylamino group, hydroxyl group, methylol group, formyl group, sulfo group (-SO ₃ H), represents a carboxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or a halogen atom, and -CH ₂ - constituting the alkyl group and alkoxy group may be substituted with -O-.]

Specific examples of the polymerizable liquid crystal compound (Y) include “3.8.6 Network (fully cross-linked)” and “6.5” in the Liquid Crystal Handbook (Liquid Crystal Handbook Editorial Committee edition, published by Maruzen Co., Ltd. on October 30, 2000). .1 liquid crystal material b. Among the compounds described in “Polymerizable nematic liquid crystal materials,” compounds having a polymerizable group, JP-A-2010-31223, JP-A-2010-270108, JP-A-2011-6360 and JP-A-2011- Examples include polymerizable liquid crystals described in No. 207765.

Both the polymerizable liquid crystal compound (X) and the polymerizable liquid crystal compound (Y) may be used horizontally aligned or vertically aligned. In addition, the polymerizable liquid crystal compound (X) and the polymerizable liquid crystal compound (Y) may each be used individually, two or more types may be used, or both may be used in combination.

The content of the polymerizable liquid crystal compound in the composition for forming a retardation layer is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 80 to 99 parts by mass, based on 100 parts by mass of solid content of the composition for forming a retardation layer. is 85 to 98 parts by mass, 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 resulting retardation layer. In addition, when the composition for forming a phase contrast layer includes two or more types of polymerizable liquid crystal compounds, it is preferable that the total amount of all liquid crystal compounds included in the composition for forming a phase contrast layer is within the above content range.

The composition for forming a phase contrast layer 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 photo polymerization initiator. However, a photo polymerization initiator is preferable because the polymerization reaction can be initiated under lower temperature conditions. do. Preferably, photopolymerization initiators that can be used in the composition for forming a polarizing layer include the same photopolymerization initiators as those exemplified above.

Since the composition for forming a retardation layer is usually applied to a base film or the like in a state dissolved in a solvent, it is preferable that it contains a solvent. The solvent is preferably a solvent that can dissolve the polymerizable liquid crystal compound, and is preferably a solvent that is inert to the polymerization reaction of the polymerizable liquid crystal compound. Examples of the solvent that can be used in the composition for forming a polarizing layer include the same solvents as those exemplified above.

Additionally, the composition for forming a retardation layer may contain, if necessary, a photosensitizer, a leveling agent, and the additives exemplified as additives contained in the composition for forming a polarizing layer. The photosensitizer and leveling agent that can be used in the composition for forming a polarizing layer include the same ones as those exemplified above.

The composition for forming a phase contrast layer can be prepared, for example, by mixing and stirring a polymerizable liquid crystal compound and, if necessary, a polymerization initiator, solvent, additives, etc.

The retardation layer is formed, for example, by applying a composition for forming a retardation layer onto a substrate or an alignment film, drying the obtained coating film, and aligning the polymerizable liquid crystal compound in the composition for forming a retardation layer, and then maintaining the orientation state. It can be obtained by polymerizing the polymerizable liquid crystal compound by irradiation of light or the like while holding it. Examples of the base material include those similar to the base film constituting the optical laminated body of the present invention. Examples of the alignment film that can be used when manufacturing the polarizing layer of the present invention include, in addition to the photo-alignment film exemplified above, an alignment film containing an orientation polymer, a groove alignment film having a concavo-convex pattern or a plurality of grooves on the surface, and the like, as desired. It can be selected appropriately depending on the orientation regulation force, etc.

Orienting polymers include, for example, polyamides and gelatins that have an amide bond in the molecule, polyimides that have an imide bond in the molecule and their hydrolyzates, polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, and polyacrylic. Amides, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters can be mentioned. Among them, polyvinyl alcohol is preferable. Orientation polymers can be used individually or in combination of two or more types.

An alignment film containing an orientation polymer is usually created by applying a composition in which the orientation polymer is dissolved in a solvent (hereinafter also referred to as “orientation polymer composition”) to a surface on which an orientation film, such as a base film, is to be formed, and then removing the solvent, or It is obtained by applying the oriented polymer composition to a substrate, removing the solvent, and rubbing (rubbing method). Examples of the solvent include the same solvents as those previously exemplified as solvents that can be used in the composition for forming a polarizing layer.

The concentration of the orientation polymer in the orientation polymer composition should be within a range in which the orientation polymer material can be completely dissolved in the solvent, but is preferably 0.1 to 20%, and more preferably about 0.1 to 10%, in terms of solid content relative to the solution.

As the alignment polymer composition, commercially available alignment film materials may be used as is. Commercially available alignment film materials include SunEver (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optimer (registered trademark, manufactured by JSR Corporation), and the like.

Methods of applying an orientation polymer composition to a surface such as a base material on which an alignment film is to be formed and methods of removing the solvent in the coating film include a method of applying a composition for forming a polarizing layer to a base film, etc., and a method of removing the solvent in the coating film. The same method can be adopted.

A rubbing oriented film is obtained by subjecting the dried film of the obtained oriented polymer composition to a rubbing treatment. As a rubbing treatment method, for example, a method of bringing a dry coating film of the above-mentioned oriented polymer composition into contact with a rubbing roll on which a rubbing cloth is wound and rotating is mentioned. When performing the rubbing treatment, if masking is performed, a plurality of regions (patterns) with different orientation directions can be formed in the alignment film.

A groove alignment film is a film having an uneven pattern or a plurality of grooves (grooves) on the film surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves aligned at equal intervals, the liquid crystal molecules are oriented in a direction along the grooves.

Methods for obtaining a groove alignment film include a method of exposing the surface of a photosensitive polyimide film through an exposure mask having pattern-shaped slits, followed by development and rinsing to form a convex-convex pattern, and using a plate-shaped disk with grooves on the surface. A method of forming a layer of UV-curable resin before curing, transferring the formed resin layer to a substrate, etc. and then curing it, and having a plurality of grooves in the UV-curable resin film before curing formed on the surface where the alignment film is to be formed. Examples include a method of pressing a roll-shaped disk to form irregularities and then hardening it.

The thickness of the alignment film (alignment film or photo-alignment film containing an orientation polymer) for forming the phase contrast layer is usually in the range of 10 to 10,000 nm, preferably in the range of 10 to 2,500 nm, and more preferably in the range of 10 to 1,000 nm. It is below, more preferably 10 to 500 nm, and particularly preferably 50 to 250 nm.

In the optical laminate of the present invention, the thickness of the retardation layer can be appropriately selected depending on the display device to which it is applied, but from the viewpoint of thinning, it is preferably 0.1 to 10 ㎛, more preferably 0.5 to 5 ㎛, even more preferably. is 1 to 3 ㎛. When the optical laminate 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 is preferably within the above range.

When the optical laminate of the present invention includes a retardation layer made of a horizontally aligned liquid crystal cured layer and a retardation layer made of a vertically aligned liquid crystal hardened layer, the vertically aligned liquid crystal cured layer is preferably disposed between the polarizing layer and the second stress relief layer. do. When comprising 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, the polarizing layer, the point adhesive layer, the first retardation layer, the second retardation layer, and the second stress relief layer are laminated in that order. It is desirable to have In this case, either a retardation layer that is a horizontally aligned liquid crystal cured layer or a retardation layer that is a vertically aligned liquid crystal cured layer may be disposed on the polarizing layer side (that is, the first retardation layer). The retardation layer made of a horizontally aligned liquid crystal cured layer and the retardation layer made of a vertically aligned liquid crystal cured layer may be bonded through a point adhesive layer, and an alignment film having a vertical alignment regulating force may or may not be interposed on the horizontally aligned liquid crystal cured layer. Alternatively, a vertically aligned liquid crystal hardened layer may be laminated, or a horizontally aligned liquid crystal hardened layer may be laminated on the vertically aligned liquid crystal cured layer, with or without an alignment film having a horizontal alignment regulating force interposed therebetween.

[Point adhesive layer]

In the present invention, the adhesive layer disposed between the polarizing layer and the retardation layer is a layer formed of an adhesive. The point adhesive layer can be formed with a known point adhesive as long as it can function as a layer for bonding the polarizing layer and the retardation layer. The adhesive or adhesive is not particularly limited, and conventionally known adhesives and adhesives can be used without particular limitation. Examples of the adhesive include adhesives having base polymers such as acrylic, rubber, urethane, silicone, and polyvinyl ether. Additionally, an energy ray curable adhesive, a heat curable adhesive, etc. may be used. Adhesives include active energy ray-curable adhesives, water-based adhesives, organic solvent-based adhesives, and solvent-free adhesives.

In one embodiment of the present invention, the adhesive layer is formed of an adhesive.

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

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

[Optical laminated body]

The optical laminate of the present invention has a desired configuration according to its use, etc., comprising a first base film, a first stress relief layer, a polarizing layer, a point adhesive layer, a retardation layer, a second stress relief layer, and a second base film, and , it can be manufactured by forming and stacking an alignment film, a diffusion prevention layer, etc., as needed, in an appropriate order according to the manufacturing method described above for each layer.

For example, in the case of having a diffusion prevention layer, it can be manufactured in the following order: forming an alignment film on the diffusion prevention layer formed on the base film, forming a polarizing layer on the alignment film, and then further forming the polarization layer on the polarization layer. A diffusion prevention layer is formed to manufacture a laminate in which a polarizing layer is formed between the two diffusion prevention layers; Separately from this, a laminate having a retardation layer is manufactured by forming a retardation layer on a base film through an alignment film, and the laminate having the retardation layer and the laminate having the polarizing layer are bonded using an adhesive. By doing so, a laminate (A) containing the base film/diffusion prevention layer/alignment film/polarizing layer/diffusion prevention layer/adhesive layer/phase contrast layer/alignment film/base film in this order is manufactured; In addition, a first stress relief layer is formed on the first base film to form a laminate (B) consisting of the first base film/first stress relief layer/base film, and the second stress relief layer on the second base film. is formed to produce a laminate (C) consisting of the second base film/second stress relief layer/base film; The base film of the laminate (A) and the base film of the laminate (B) are peeled, the diffusion prevention layer and the first stress relief layer are bonded, and the base films of both outer layers of the laminate (A) and the laminate (B) are bonded. The base film of and the base film of the laminate (C) are peeled off, respectively, and the diffusion prevention layer, the first stress relief layer, the retardation layer, and the second stress relief layer are bonded, respectively, to form a first base film/first stress relief layer/ An optical laminate containing the diffusion prevention layer/alignment film/polarizing layer/diffusion prevention layer/adhesive layer/phase contrast layer/alignment film/second stress relief layer/second base film in this order is obtained.

In the optical laminate of the present invention, the total thickness of the layers located between the first stress relief layer and the second stress relief layer is 20 μm or less. The present invention has a structure suitable for suppressing the occurrence of bonding misalignment or wrinkles that tend to occur during transfer in a thin optical laminate, and is disposed between the first stress relief layer and the second stress relief layer, In a laminate having a thin structure (laminated body) for bringing about a circularly polarized light function including a polarizing layer and a retardation layer, it is easy to obtain a more remarkable effect of the present invention. In the present invention, the total thickness of the layers located between the first stress relief layer and the second stress relief layer varies depending on the desired layer configuration, but is preferably 18 μm or less, more preferably 16 μm or less. . The lower limit of the total thickness of the layers located between the first stress relief layer and the second stress relief layer is not particularly limited, but is usually 5 μm or more.

In one embodiment of the present invention, the peeling force (F1) when peeling the first base film from the optical laminate and the peeling force (F2) when peeling the second base film from the optical laminate are expressed by the formula (2) :

0.02 (N/25 ㎜) ≤ ｜F1 - F2｜ (2)

It is desirable to satisfy.

If the peeling force F1 and the peeling force F2 satisfy the relationship shown in the above equation (2), there is an appropriate strength/weakness between the adhesion force of the first base film in the optical laminate and the adhesion power of the second base film in the optical laminate. A relationship arises. For this reason, when the above relationship is satisfied, the first substrate and the second substrate can be easily peeled from the optical laminate in a desired order. In particular, if the peeling force of the base film that is peeled first from the optical laminate is smaller than the peeling force of the base film that is peeled off later, the base film is likely to peel, and it is difficult for bonding misalignment or wrinkles to occur when transferring to the transfer object. Lose. As a result, the effect of suppressing the deterioration of the optical performance of the optical laminated body resulting from transfer can be expected. Since this effect can be more easily improved, 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. Moreover, 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, and more preferably 0.08 N/25 mm or less. The value of F1 - F2 can be controlled by adjusting the peel force F1 and peel force F2, respectively.

Typically, the peel force F1 and the peel force F2 are designed so that the peel force on the side of the substrate that is peeled first is smaller than the peel force on the side of the substrate that is peeled later.

In the present invention, the peeling force F1 is preferably less than 0.30 N/25 mm, more preferably less than 0.25 N/25 mm, and even more preferably less than 0.15 N/25 mm. If the upper limit of the peeling force F1 is within the above range, it is easy to peel the first base film from the optical laminate, and in relation to the peeling force F2, the peeling force F1 is controlled to a range effective in suppressing bonding misalignment or wrinkles, etc. easy. Moreover, the peeling force F1 is preferably 0.04 N/25 mm or more, more preferably 0.06 N/25 mm or more, and even more preferably 0.08 N/25 mm or more.

If the peeling force F1 is more than the above lower limit, ease of peeling when peeling the first base film from the optical laminate is ensured, and unintentional peeling of the first base film before transfer for mounting the laminate on a display device, etc. can be suppressed. You can.

In the present invention, the peeling force F2 is preferably less than 0.30 N/25 mm, more preferably less than 0.25 N/25 mm, and even more preferably less than 0.15 N/25 mm. If the upper limit of the peeling force F2 is within the above range, it is easy to peel the second base film from the optical laminate, and wrinkles, bonding misalignment, and bubbles that may occur when peeling and transferring the second base film to the substrate are prevented. The suppression effect is easy to improve. Moreover, the peeling force F2 is preferably 0.01 N/25 mm or more, more preferably 0.02 N/25 mm or more, and even more preferably 0.03 N/25 mm or more. If the peeling force F2 is more than the above lower limit, ease of peeling is ensured when peeling the second base film from the optical laminate, and unintentional peeling of the second base film before transfer for mounting the laminate on a display device, etc. can be suppressed. You can.

The peeling forces F1 and F2 are, respectively, the base film on the opposite side to the base film for measuring the peeling force of the optical laminated body to be measured (for example, the second base film when measuring F1, the first base film when measuring F2) In a test piece in which the surface from which the base film was peeled is bonded to a glass plate with an adhesive and fixed, the peeling required to peel the first base film or the second base film for which the peeling force is to be measured from the optical laminate of the test piece. It is a value measured as force. The measurement of the peeling force can be performed according to the 90° peeling test method specified in JIS K6854-1:1999. The detailed measurement method of peel force F1 and F2 is described in the Examples described later.

Peeling force F1 and peeling force F2 are, for example, the configuration of the layer adjacent to the first base film and the second base film and its thickness, the type and thickness of the first base film and the second base film, and the first base film and the second base film. It can be adjusted by surface treatment of the base film, the second base film, and/or the layer adjacent to these base films. For example, by performing a modification treatment on the surface of the first base film and/or the second base film, or forming a peeling force adjustment layer as a layer adjacent to the first base film or the second base film, the first base film The peeling force of the film or the second base film from the optical laminate can be controlled.

In the optical laminate of the present invention, the peelable first base film and the peelable second base film constituting the optical laminate are both peeled, and only the laminate structure having a circular polarizer function is transferred to the transfer target and used. . The optical laminate of the present invention is provided with a first stress relief layer and a second stress relief layer, and is excellent in the effect of suppressing the occurrence of bonding misalignment and wrinkles when peeling the base film and transferring it to a substrate. The optical laminate of the present invention can be easily manufactured by sequentially forming the first or second substrates from the optical laminate in a desired order using a general apparatus that has been widely used in the field for producing optical films, optical laminates, etc. It can be easily peeled off.

Although the optical laminate of the present invention is thin, bonding misalignment or wrinkles resulting from peeling of the base film are unlikely to occur, and high optical performance in the laminate after transfer can be expected. For this reason, the optical laminated body of the present invention can be suitably used in the manufacture of various display devices.

A display device is a device that has a display element and includes a light-emitting element or light-emitting device as a light-emitting source. The display device includes a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, and an electromagnetic emission display device (e.g., an electric field emission display device ( FED), Surface Field Emission Display (SED)), electronic paper (display devices using electronic ink or electrophoretic elements, plasma display devices, projection display devices (e.g. Grating Light Valve (GLV) display devices, digital micromirrors) display devices (display devices having DMD) and piezoelectric ceramic displays, etc. Liquid crystal displays include transmissive liquid crystal displays, transflective liquid crystal displays, reflective liquid crystal displays, direct-view liquid crystal displays, and projection-type liquid crystal displays. This includes all devices, etc. These display devices may be display devices that display two-dimensional images, or may be stereoscopic display devices that display three-dimensional images.

Example

Hereinafter, the present invention will be described in more detail through examples and comparative examples. “%” and “part” in examples and comparative examples are “% by mass” and “part by mass” unless otherwise specified.

1. Preparation of laminate A1

(1) Preparation of water-soluble polymer (1)

According to the following synthesis scheme, water-soluble polymer (1) consisting of the following structural units was obtained.

[Formula 17]

In 400 g of dimethyl sulfoxide, 20 g of polyvinyl alcohol with a molecular weight of 1000 (manufactured by Wako Pure Chemical Industries, Ltd.), 0.55 mg of N,N-dimethyl-4-aminopyridine as a nucleating agent, and 4.6 g of triethylamine were dissolved, The temperature was raised to 60°C while stirring. After that, a solution in which 10.5 g of methacrylic anhydride was dissolved in 50 g of dimethyl sulfoxide was added dropwise over 1 hour, and the reaction was carried out 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 to completely mix, thereby adjusting the ratio (mass) of the reaction solution to methanol to be 1:1. By gradually adding 1500 mL of acetone to this solution, the water-soluble polymer (1) was crystallized by a crystallization method. The solution containing the obtained white crystals was filtered, washed well with acetone, and then vacuum dried to obtain 20.2 g of water-soluble polymer (1). The obtained water-soluble polymer (1) was dissolved in water to prepare a 3% by mass aqueous solution of water-soluble polymer (1).

(2) Preparation of composition for forming photo-alignment film

The following components were mixed, and the resulting mixture was stirred at 80°C for 1 hour to obtain a composition for forming a photo-alignment film.

Photo-alignment polymer: 2 parts of polymer described in Japanese Patent Application Laid-Open No. 2013-033249 (number average molecular weight: about 28200, Mw/Mn: 1.82)

[Formula 18]

· Solvent: o-xylene 98 parts

(3) Preparation of composition for forming polarizing layer

The composition for forming a polarizing layer was obtained by mixing each of the following components and stirring at 80°C for 1 hour. As the dichroic dye, the azo dye described in the examples of Japanese Patent Application Laid-Open No. 2013-101328 was used.

·Polymerizable liquid crystal compound: A1 75 parts

[Formula 19]

·Polymerizable liquid crystal compound: A2 25 parts

[Formula 20]

・Dichroic dye: Azo dye 1 2.5 parts

[Formula 21]

・Dichroic dye: Azo dye 2 2.5 parts

[Formula 22]

・Dichroic dye: Azo dye 3 2.5 parts

[Formula 23]

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: 1.2 parts of polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)

· Solvent: o-xylene 250 parts

(4) Preparation of composition for forming phase contrast layer

The composition for forming a phase difference layer was obtained by mixing each of the following components and stirring at 80°C for 1 hour.

·Polymerizable liquid crystal compound: X1 100 parts

[Formula 24]

·Polymerizable liquid crystal compound: X2 33 parts

[Formula 25]

Polymerization initiator: 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure (registered trademark) 369; manufactured by BASF Japan) 8 parts

Leveling agent: 0.1 part of polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)

・Other additives: LALOMER LR9000 (manufactured by BASF Japan) 6.7 parts

Solvent: Cyclopentanone 546 parts

Solvent: N-methylpyrrolidone 364 parts

(5) Manufacturing of polarizer (1)

As base material 1, 3% by mass prepared above was applied to the release-treated surface of a release polyethylene terephthalate (PET) film (“FF-50” manufactured by Unitica Co., Ltd., PET film with one-side release treatment, base material thickness: 50 μm). The water-soluble polymer (1) aqueous solution was applied with a bar coater and dried at 100°C for 2 minutes to form a 2 µm anti-diffusion layer A consisting of a water-soluble polymer (1) film.

After plasma treatment was performed 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. This coating film was dried at 100°C for 2 minutes to remove the solvent and form a dry film. The dried film was irradiated with polarized UV light at an intensity of 20 mJ/cm2 (based on 313 nm) to provide an orientation regulating force, thereby forming a 50 nm photo-alignment film A.

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. Additionally, the solvent was removed by drying at 110°C for 2 minutes and the polymerizable liquid crystal compound was phase-transformed into a liquid phase, and then cooled to room temperature to phase-transfer the polymerizable liquid crystal compound into a smectic liquid crystal state. Thereafter, the obtained dry film was irradiated with ultraviolet light at 1000 mJ/cm2 (based on 365 nm) using a high-pressure mercury lamp, and polymerized while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound contained in the dry film, thereby producing 3 A ㎛ polarizing layer was formed.

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

(6) Preparation of retardation film (1)

As base material 2, a release polyethylene terephthalate (PET) film (“FF-50” manufactured by Unitica Co., Ltd., PET film with release treatment on one side, thickness of base material: 50 μm) was subjected to corona treatment on the surface opposite to the release treatment surface. After this, the composition for forming a photo-alignment layer was applied using a bar coater. The obtained coating film was dried at 120°C for 2 minutes and then cooled to room temperature to form a dry film. After that, 100 mJ (based on 313 nm) of polarized ultraviolet light was irradiated to form a 100 nm photo-alignment film B.

On the obtained photo-alignment film B, the composition for forming a phase difference layer was applied using 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. Next, using an ultraviolet light irradiation device, the dried film is irradiated with ultraviolet light at an exposure amount of 1000 mJ/cm2 (based on 365 nm), thereby curing the polymerizable liquid crystal compound in a state of orientation in the horizontal direction with respect to the substrate surface. A µm-thick retardation layer was formed to obtain a retardation film (1) consisting of base material 2/photo-alignment film B/retardation layer (horizontally aligned liquid crystal cured layer).

(7) Production of laminate A1

The diffusion prevention layer B side of the polarizing plate (1) prepared above and the retardation layer side of the retardation film (1) are interposed through an adhesive (manufactured by Lintec, pressure-sensitive adhesive, 5 μm thick), and the absorption axis of the polarizing plate (1) is retardated. The film (1) is bonded so that the angle formed by the slow axis is 45°, and consists of base material 1/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment layer B/base material 2. Laminate A1 was obtained.

2. Preparation of laminate A2

(1) Preparation of oriented polymer composition (1)

According to the composition shown in Table 1, 2-butoxyethanol was added to SanEver SE-610 (manufactured by Nissan Chemical Industries, Ltd.), a commercially available orientation polymer, to prepare an orientation polymer composition (1). In addition, the values in Table 1 represent 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 stated in the delivery specification.

(2) Preparation of composition for forming vertically aligned liquid crystal cured layer

The composition of the composition for forming a vertically aligned liquid crystal cured layer is shown in Table 2. Each component was mixed, and the resulting solution was stirred at 80°C for 1 hour and then cooled to room temperature to obtain a composition for forming a vertically aligned liquid crystal cured layer.

The values in parentheses in Table 2 represent the content ratio of each component relative to the total amount of the prepared composition.

In Table 2, LR9000 is Laromer (registered trademark) LR-9000 manufactured by BASF Japan, Irg907 is Irgacure (registered trademark) 907 manufactured by BASF Japan, and BYK361N is a leveling agent manufactured by Big Chemi Japan. , LC242 represents a polymerizable liquid crystal manufactured by BASF represented by the following formula, and PGMEA represents propylene glycol 1-monomethyl ether 2-acetate.

[Formula 26]

(3) Production of a laminate containing a vertically aligned liquid crystal cured layer

As the base material 3, the surface of a cycloolefin polymer film (COP) (ZF-14, manufactured by Nippon Zeon Co., Ltd.) was treated once using a corona treatment device under the conditions of an output of 0.3 kW and a processing speed of 3 m/min. The orientation polymer composition (1) was applied to the corona-treated surface using a bar coater and dried at 90°C for 1 minute to obtain an orientation film C. The film thickness of the obtained alignment film C was measured using a laser microscope and was found to be 1 μm. Next, the composition for forming a vertically aligned liquid crystal cured layer was applied onto 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 a nitrogen atmosphere, at a wavelength of 365 nm). (i.e., integrated light amount: 1000 mJ/cm2), thereby forming a vertically aligned liquid crystal cured layer with a thickness of 500 nm cured in a state where the polymerizable liquid crystal compound is aligned in the direction perpendicular to the inside of the substrate surface, and substrate 3/alignment film C/vertical A laminate consisting of an aligned liquid crystal cured layer was obtained.

(4) Preparation of curable composition for forming adhesive layer

The cationically polymerizable compound and the cationic polymerization initiator described below were mixed and then defoamed to prepare a cationically polymerizable curable composition for forming an adhesive layer.

In addition, the cationic polymerization initiator was blended as a 50% by mass propylene carbonate solution, and its solid content was shown.

・1,6-hexanediol diglycidyl ether (Product name: EX-212L, manufactured by Nagase Chemtex Co., Ltd.) 25 parts

10 parts of 4-hydroxybutyl vinyl ether

·Bisphenol F type epoxy resin (Product name: EXA-830CRP, manufactured by DIC Co., Ltd.) 65 parts

・Cationic polymerization initiator (Product name: CPI-100P, manufactured by San-Apro Co., Ltd., 50 mass% solution) 3 parts

(5) Production of laminate A2

After corona treatment was applied to the surface of the vertically aligned liquid crystal cured layer of the laminate consisting of the base material 3/alignment film C/vertically aligned liquid crystal cured layer prepared above, the base material 2 of the laminate A1 was peeled off, and the exposed surface and the corona The treated surfaces of the vertically aligned liquid crystal cured layer were bonded together via a curable composition for forming an adhesive layer, and exposed using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Electric Co., Ltd.) at an exposure dose of 500 mJ/cm2 (based on 365 nm). ) was irradiated with ultraviolet rays. As a result, a laminate A2 consisting of base material 1/diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment film B/adhesive layer/vertically aligned liquid crystal cured layer/alignment film C/base material 3 was obtained. . Additionally, the thickness of the adhesive layer was 2 μm.

3. Manufacturing of a laminate containing a stress relief layer

(1) Polymerization Example 1: Preparation of acrylic resin solution (1)

A mixed solution of 81.8 parts of acetone, 98.4 parts of butyl acrylate, 0.6 parts of acrylic acid, and 1.0 part of 2-hydroxyethyl acrylate was injected into a reactor equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, and a stirrer, and the air in the device was purged with nitrogen gas. was replaced to make it oxygen-free, and the internal temperature was raised to 55°C. After that, the entire solution of 0.14 parts of azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts of acetone was added. 1 hour after adding the polymerization initiator, acetone was continuously added to the reactor at an addition rate of 17.3 parts/hr so that the concentration of the acrylic resin excluding the monomer was 35%, and the reaction was kept at an internal temperature of 54 to 56°C for 12 hours, and finally Ethyl acetate was added to adjust the concentration of the acrylic resin to 20%. In this way, acrylic resin solution (1) was obtained.

(2) Polymerization Example 2: Preparation of acrylic resin solution (2)

Acrylic resin solution (2) was obtained in the same manner as in Polymerization Example 1, except that the composition of the monomers was changed to 78.0 parts of butyl acrylate, 20 parts of methyl methacrylate, 1.0 part of acrylic acid, and 1.0 part of 2-hydroxyethyl acrylate.

(3) Polymerization Example 3: Preparation of acrylic resin solution (3)

A mixed solution of 91 parts of ethyl acetate, 43 parts of 2-ethylhexyl acrylate, 55 parts of butyl acrylate, and 2.0 parts of 2-hydroxyethyl acrylate was injected into a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, and a stirrer, and nitrogen The air in the device was replaced with gas to make it oxygen-free, and the internal temperature was raised to 55°C. After that, the entire solution of 0.14 parts of azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts of ethyl acetate was added. After adding the polymerization initiator, this temperature was maintained for 1 hour, and then ethyl acetate was continuously added into the reaction vessel while maintaining the internal temperature at 54 to 56°C, when the concentration of the (meth)acrylic resin reached 35%. The addition of ethyl acetate was stopped, and the temperature was maintained at this temperature until 10 hours had elapsed from the start of the addition of ethyl acetate.

Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% to prepare an acrylic resin solution (3).

(4) Polymerization Example 4: Preparation of acrylic resin solution (4)

81.8 parts of ethyl acetate, 98.0 parts of butyl acrylate, and 2.0 parts of acrylic acid were injected into a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, and a stirrer, and the air in the device was replaced with nitrogen gas to make it oxygen-free, and the internal temperature was adjusted to Raised to 55°C. After that, the entire solution of 0.14 parts of azobisisobutyronitrile, which is a polymerization initiator, dissolved in 10 parts of ethyl acetate was added.

After adding the initiator, this temperature was maintained for 1 hour, and then, while maintaining the internal temperature at 54 to 56°C, ethyl acetate was continuously added into the reaction vessel at an addition rate of 17.3 parts/hr until the acrylic resin concentration was 35%. At this point, the addition of ethyl acetate was stopped, and the temperature was maintained at this temperature until 12 hours had elapsed from the start of the addition of ethyl acetate. Finally, ethyl acetate was added and the acrylic resin concentration was adjusted to 20% to prepare an acrylic resin solution (4).

(5) Preparation of composition (1) for forming peeling force adjustment layer

KBM-5103 (manufactured by Shin-Etsu Silicone), a silane coupling agent, was dissolved in o-xylene in an amount of 0.25% by weight to prepare a composition (1) for forming a peeling force adjustment layer.

(6) Preparation of composition (2) for forming peeling force adjustment layer

KBE-903 (manufactured by Shin-Etsu Silicone), a silane coupling agent, was dissolved in o-xylene in an amount of 0.25% by weight to prepare a composition (2) for forming a peeling force adjustment layer.

(7) Production of laminate A3 containing stress relief layer A

(i) Preparation of composition (1) for forming stress relief layer

According to the following composition, composition (1) for forming a stress relief layer was prepared.

Acrylic resin (1) obtained in Polymerization Example 1: 100 parts (non-volatile content)

· Isocyanate-based compound: Colonate L, ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solids concentration 75%) (manufactured by Tosoh Corporation) 0.5 part

・Silane-based compound: KBM-403, 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 part

were mixed, and ethyl acetate was added so that the solid content concentration was 10%, to obtain a composition for forming a stress relief layer (1).

(ii) Substrate to which peeling force adjustment layer is attached (Substrate A)

The composition (1) for forming a peeling force adjustment layer was applied to the non-release-treated side of a polyethylene terephthalate film (thickness 38 µm) on one side of which had been release-treated, by a bar coat method, and heated in an oven at 120°C. After drying for a minute, a base material with a peeling force adjustment layer (substrate A) was obtained.

(iii) Preparation of laminate A3 containing stress relief layer

The composition for forming a stress relief layer (1) was applied to the surface of the base material A having the peeling force adjustment layer using an applicator so that the thickness after drying was 15 μm. The application layer was dried at 100°C for 1 minute, and a film provided with the stress relief layer A was obtained. Thereafter, another polyethylene terephthalate film (thickness 38 μm) (base material B) that had been subjected to release treatment was bonded onto the stress relief layer A, and cured for 7 days under conditions of a temperature of 23°C and a relative humidity of 50%RH, forming base material A. Laminate A3 provided with stress relief layer A, consisting of /stress relief layer A/base material B, was obtained.

(8) Production of laminate A4 containing stress relief layer B

Stress relief layer B was made of base material A/stress relief layer B/base B in the same manner as the production of laminate A3 consisting of base material A/stress relief layer A/base material except that the thickness of the stress relief layer was 25 μm. A laminate A4 having was manufactured.

(9) Production of laminate A5 containing stress relief layer C

Stress relief layer C consisting of base material A/stress relief layer C/base B was manufactured in the same manner as the production of laminate A3 consisting of base material A/stress relief layer A/base material B except that the thickness of the stress relief layer was 50 μm. A laminate A5 having was manufactured.

(10) Production of laminate A6 containing stress relief layer D

(i) Preparation of composition (2) for forming stress relief layer

Composition (2) for forming a stress relief layer was prepared according to the following composition.

Acrylic resin obtained in Polymerization Example 2: 100 parts (non-volatile amount)

·Colonate L: 3.0 parts

·KBM-403: 0.5 parts

was mixed. Ethyl acetate was added so that the solid content concentration was 10%, and composition (2) for forming a stress relief layer was obtained. Additionally, Colonate L and KBM-403 are the same as those used in the production of composition (1) for forming a stress relief layer.

(ii) Preparation of laminate A6 containing stress relief layer D

Using the obtained composition for forming a stress relief layer (2), in the same manner as the production of laminate A3 consisting of base material A/stress relief layer A/base material B, base material A is provided with a stress relief layer D having a thickness of 15 μm. Laminate A6 consisting of /stress relief layer D/base material B was manufactured.

(11) Production of laminate A7 containing stress relief layer B

A laminate consisting of base material A/stress relief layer A/base material B, except that the composition for forming a stress relief layer (1) was applied to the release-treated surface of a polyethylene terephthalate film (thickness 38 μm) (base material B) that had been subjected to release treatment. In the same manner as the production of A3, laminate A7 consisting of base material B/stress relief layer A/base material B was manufactured.

(12) Production of laminate A8 containing stress relief layer A

The composition (2) for forming a peeling force adjustment layer was applied to the non-release-treated side of a polyethylene terephthalate film (thickness 38 µm) on one side of which had been release-treated, by a bar coat method, and heated in an oven at 120°C for 1 time. After drying for a minute, a base material with a peeling force adjustment layer (substrate C) was obtained. Except that the composition for forming a stress relief layer (1) was applied to the surface of the base C having the peeling force adjustment layer, the base material C/ Laminate A8 consisting of stress relief layer A/base material B was manufactured.

(13) Production of laminate A9 containing stress relief layer E

(i) Preparation of composition (3) for forming stress relief layer

According to the following composition, composition (3) for forming a stress relief layer was prepared.

Acrylic resin obtained in Polymerization Example 3: 100 parts (non-volatile amount)

·Colonate L: 0.3 part

·KBM-403: 0.25 parts

was mixed. Ethyl acetate was added so that the solid content concentration was 15%, and composition (3) for forming a stress relief layer was obtained.

(ii) Preparation of laminate A9 comprising stress relief layer E

Using the obtained composition for forming a stress relief layer (3), in the same manner as the production of laminate A3 consisting of base material A/stress relief layer A/substrate B, base material A is provided with a stress relief layer E with a thickness of 15 μm. Laminate A9 consisting of /stress relief layer E/base material B was manufactured.

(14) Production of laminate A10 containing stress relief layer F

(i) Preparation of composition (4) for forming stress relief layer

According to the following composition, composition (4) for forming a stress relief layer was prepared.

Acrylic resin obtained in Polymerization Example 4: 80 parts (non-volatile amount)

・A-DOG, a bifunctional acrylate obtained from Shinnakamura Chemical Industry Co., Ltd.: solid content 20 parts

·Colonate L: 3.0 parts

·KBM-403: 0.5 parts

· Photopolymerization initiator (Irgacure 500): 1.5 parts

was mixed. Ethyl acetate was added so that the solid content concentration was 13%, and composition (4) for forming a stress relief layer was obtained.

In addition, A-DOG is a diacrylate of an acetal compound of hydroxypivaldehyde and trimethylolpropane, and has the structure shown below.

(ii) Preparation of laminate A10 containing stress relief layer F

The composition (4) for forming a stress relief layer was applied to the surface of the base material A having the peeling force adjustment layer using an applicator so that the thickness after drying was 15 μm, and the applied layer was dried at 100°C for 1 minute. After that, another polyethylene terephthalate film (thickness 38 μm) (base material B) that has been subjected to release treatment is bonded onto the application layer, and the integrated light amount of ultraviolet rays is adjusted by the D valve of the Fusion UV lamp system (manufactured by Fusion UV Systems). The applied layer was cured by irradiation at 1500 mJ/cm2. Next, it was cured for 7 days under conditions of a temperature of 23°C and a relative humidity of 50%RH to obtain a laminate A10 including a stress relief layer F composed of base material A/stress relief layer F/base material B.

(15) Production of laminate A11 containing stress relief layer B

Stress relief layer B was made of base material B/stress relief layer B/base material in the same manner as the production of laminate A7 made of base material B/stress relief layer A/base material except that the thickness of the stress relief layer was 25 μm. Laminate A11 having was manufactured.

(16) Production of laminate A12 containing stress relief layer C

Stress relief layer C consisting of base material B/stress relief layer C/base B was manufactured in the same manner as the production of laminate A7 consisting of base material B/stress relief layer A/base material except that the thickness of the stress relief layer was 50 μm. A laminate A12 having was manufactured.

4. Fabrication of optical laminates

(1) Example 1

The surface exposed by peeling off the base material 2 of the laminate A1 consisting of base material 1/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/retardation layer/photo-alignment layer B/substrate 2, and base material B/stress The base material B of the laminate A7 made of relief layer A/substrate B is peeled off and the exposed surfaces are bonded to form a base material 1/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment layer. An optical laminate B1 consisting of B/stress relief layer A/base material B was manufactured. In addition, the surface exposed by peeling the base material 1 of the optical laminate B1 and the surface exposed by peeling the base material B of the laminate A3 consisting of base material A/stress relief layer A/substrate B are bonded to each other to form base material A/stress relief layer. An optical laminate (1) consisting of relaxation layer A/diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment film B/stress relaxation layer A/substrate B was obtained.

(2) Example 2

In the same manner as in Example 1, except that laminate A4 was used instead of laminate A3, and the surface exposed by peeling off the base material 1 of optical laminate B1 was bonded to the surface exposed by peeling the base material B of laminate A4. Thus, an optical laminate (2) consisting of base material A/stress relief layer B/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo alignment layer B/stress relief layer A/substrate B. got it

(3) Example 3

Laminate A5 was used instead of laminate A3, and the surface exposed by peeling off the base material 1 of the optical laminate B1 was bonded to the surface exposed by peeling the base material B of the laminate A5. Thus, an optical laminate (3) consisting of base material A/stress relief layer C/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment layer B/stress relief layer A/substrate B. got it

(4) Example 4

The same procedure as in Example 1 was carried out except that Laminate A8 was used instead of Laminate A7, and the surface exposed by peeling off the base material 2 of Laminate A1 was bonded to the surface exposed by peeling off the base material B of Laminate A8. , Base A/Stress Relief Layer A/Diffusion Prevention Layer A/Photo-Alignment Film A/Polarizing Layer/Diffusion Prevention Layer B/Adhesive Layer/Phase Contrast Layer/Photo-Alignment Film B/Stress Relief Layer A/Base C. got it

(5) Example 5

Laminate A6 was used instead of laminate A3, and the surface exposed by peeling off the base material 1 of the optical laminate B1 was bonded to the surface exposed by peeling the base material B of the laminate A6. Thus, an optical laminate made of base material A/stress relief layer D/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment layer B/stress relief layer A/substrate B (5) got it

(6) Example 6

Base material 3 of laminate A2 consisting of base material 1/diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment film B/adhesive layer/vertically aligned liquid crystal cured layer/alignment film C/base material 3 The peeled and exposed surface and the peeled and exposed surface of the base material B of the laminate A7 consisting of base material B/stress relief layer A/substrate B are bonded to each other, and the base material 1/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion layer is bonded. An optical laminate B2 consisting of prevention layer B/adhesive layer/retardation layer/photo-alignment film B/adhesive layer/vertically aligned liquid crystal cured layer/alignment film C/stress relief layer A/substrate B was manufactured. In addition, the surface exposed by peeling the base material 1 of the optical laminate B2 and the surface exposed by peeling the base material B of the laminate A3 consisting of base material A/stress relief layer A/substrate B are bonded to each other, so that the base material A/stress relief layer A/substrate B is bonded. Optics made of relaxation layer A/diffusion prevention layer A/light alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/light alignment layer B/adhesive layer/vertically aligned liquid crystal cured layer/alignment layer C/stress relief layer A/substrate B Laminate (6) was obtained.

(7) Example 7

In the same manner as in Example 2, except that laminate A11 was used instead of laminate A7, and the surface exposed by peeling off the base material 2 of optical laminate A1 was bonded to the surface exposed by peeling the base material B of laminate A11. Thus, an optical laminate made of base material A/stress relief layer B/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment layer B/stress relief layer B/substrate B (7) got it

(8) Example 8

In the same manner as in Example 2, except that laminate A12 was used instead of laminate A7, and the surface exposed by peeling off the base material 2 of optical laminate A1 was bonded to the surface exposed by peeling the base material B of laminate A12. Thus, an optical laminate consisting of base material A/stress relief layer B/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment layer B/stress relief layer C/substrate B (8) got it

(9) Example 9

Laminate A9 was used instead of laminate A3, and the surface exposed by peeling off the base material 1 of the optical laminate B1 was bonded to the surface exposed by peeling the base material B of the laminate A9. Thus, an optical laminate (9) made of base material A/stress relief layer E/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo alignment layer B/stress relief layer A/substrate B. got it

(10) Example 10

In the same manner as in Example 1, except that laminate A10 was used instead of laminate A3, and the surface exposed by peeling off the base material 1 of optical laminate B1 was bonded to the surface exposed by peeling the base material B of laminate A10. Thus, an optical laminate (10) made of base material A/stress relief layer F/diffusion prevention layer A/photo-alignment layer A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/photo-alignment layer B/stress relief layer A/substrate B. got it

(11) Comparative Example 1

The base material 1 of the optical laminate B1 manufactured in the same manner as in Example 1 was peeled, and diffusion prevention layer A/photo-alignment film A/polarizing layer/diffusion prevention layer B/adhesive layer/phase contrast layer/alignment film B/stress relaxation was carried out. An optical laminate (11) consisting of layer A/substrate B was obtained.

5. Evaluation of physical properties/properties of optical laminate

(1) Storage modulus of stress relief layer

The storage elastic modulus was measured by laminating an adhesive with a thickness of 30 μm, producing a cylindrical test piece with a thickness of 8 mmϕ × 3 mm, and using a torsional shear method under the following conditions.

Measuring device: Dynamic viscoelasticity measuring device “DYNAMIC ANALYZER RDA II” manufactured by Rheometric.

Frequency: 1 Hz

Temperature: 23℃

(2) Peeling force of the first base film and the second base film

In the optical laminates (1) to (11) manufactured in Examples 1 to 10 and Comparative Example 1, the base material on the polarizing layer side was the first base film, the base material on the retardation side was the second base film, and the first base material The peeling force F1 when peeling the film from the optical layered body and the peeling force F2 when peeling the second base film from the optical layered body were each measured by the following method. The results are shown in Table 3.

Using a tensile tester, one end of a test piece (width 25 mm , JIS K 6854-1: 1999 "Adhesive - Peel adhesion strength test method - Part 1: 90 degree peel" was performed and measured.

(3) Elasticity modulus of the first base film (23°C)

A test piece with an MD length of 100 mm x a TD length of 25 mm was cut from the base film. Next, with the upper and lower grippers of a tensile tester (AUTOGRAPH AG-1S tester manufactured by Shimadzu Corporation), both ends of the long side of the test piece are sandwiched so that the interval between the grippers is 5 cm, and the temperature is 23°C and the relative humidity is 55%. Under the environment, the test piece was stretched in the longitudinal direction at a tensile speed of 1 mm/min, and the tensile modulus [MPa] in MD at 23°C was calculated from the slope of the initial straight line in the obtained stress-strain curve. The elastic modulus (23°C) of the first base film (base material A) in Examples 1 to 10 was 4800 MPa.

(4) Bonding test

Each of the optical laminates (1) to (11) manufactured in the Examples and Comparative Examples was cut into sheets of 160 mm × 80 mm, and the first The second base film was peeled off with the side of the base film adsorbed, and the exposed side of the second stress relief layer was bonded to the glass. Afterwards, the appearance was inspected, and if appearance defects (bubble, wrinkles, lifting, tearing of the first base material) were confirmed, the bonding failed, and if no appearance defects were confirmed, the bonding was considered successful, and the test was performed 20 times. . Test results were classified based on success rate. The results are shown in Table 3.

＜Evaluation criteria＞

○: Success rate 90% or more

△: Success rate 60% or more but less than 90%

×: Success rate less than 60%

(5) bending test

Each of the optical laminates (1) to (11) manufactured in Examples and Comparative Examples was cut into 25 mm x 200 mm, and tested with a cylindrical mandrel method bending resistance tester Type II (manufactured by TP Engineering Co., Ltd.). Using this, the cut film is placed on a mandrel rod with a diameter of 2 mm (bending radius R = 1 mm) under the conditions of a temperature of 25°C and a relative humidity of 55% RH, with the cured layer of the composition for forming the first resin layer facing the outside. A coiled flexibility test was conducted. The film after the test was used, and visually inspected with transmitted light in a dark room environment, the occurrence of cracks was observed, and the observation results were classified.

＜Evaluation criteria＞

○: Cracks were not recognized.

△: Almost no cracks were seen.

×: Significant cracking was confirmed.

In Table 3, the thickness of the layer between the first stress relief layer and the second stress relief layer does not include the thicknesses of the first stress relief layer and the second stress relief layer (thicknesses in the table are set to the first decimal place). (This is a rounded value).

1: First base film
2: first stress relief layer
3: Polarizing layer
4: Point adhesive layer
5: Phase difference layer
6: second stress relief layer
7: Second base film
8, 9: Anti-diffusion layer
11: Optical laminate
12, 13: Laminate structure

Claims (10)

An optical laminate comprising a first base film, a first stress relief layer, a polarizing layer, a point adhesive layer, a retardation layer, a second stress relief layer, and a second base film in this order,
The total thickness of the layers located between the first stress relief layer and the second stress relief layer is 20 μm or less,
The storage modulus of the first stress relief layer is 1.5 MPa or less,
An optical laminate wherein both the first base film and the second base film are peelable base films. According to claim 1,
An optical laminate, comprising an additional anti-diffusion layer between the first stress relief layer and the polarizing layer. The method of claim 1 or 2,
An optical laminate wherein the polarizing layer is a liquid crystal cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting a smectic liquid crystalline phase and a dichroic dye. The method according to any one of claims 1 to 3,
An optical laminate wherein the retardation layer is a horizontally aligned liquid crystal cured layer cured in a state in which a polymerizable liquid crystal compound is oriented horizontally with respect to the substrate surface. The method according to any one of claims 1 to 4,
An optical laminate wherein the first base film has an elastic modulus of 2,500 to 6,000 MPa at 23°C. The method according to any one of claims 1 to 5,
An optical laminate wherein the first stress relief layer has a thickness of 10 to 80 μm. The method according to any one of claims 1 to 6,
The thickness of the first stress relief layer (T1) and the thickness of the second stress relief layer (T2) are expressed in Equation (1):
T1/T2 ≥ 1.0 (1)
An optical laminate that satisfies the above. The method according to any one of claims 1 to 7,
The peeling force (F1) when peeling the first base film from the optical laminate and the peeling force (F2) when peeling the second base film from the optical laminate are expressed in Equation (2):
0.02 (N/25 ㎜) ≤ ｜F1 - F2｜ (2)
An optical laminate that satisfies the above. According to any one of claims 2 to 8,
An optical laminate wherein the anti-diffusion layer has a thickness of 5 μm or less. The method according to any one of claims 1 to 9,
An optical laminate further comprising a vertically aligned liquid crystal cured layer in which the polymerizable liquid crystal compound is oriented in a direction perpendicular to the substrate surface between the polarizing layer and the second stress relief layer.

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