JP2006267671A - Polymer laminate and retardation plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer laminate, capable of obtaining a retardation plate superior in stability with the lapse of time, without hindrance to alignment in liquid crystal molecules when it is made into the retardation plate, by laminating optical anisotropic layers, in the polymer laminate, having both the function of an optical alignment layer for aligning the liquid crystal, and the function of a shielding layer. <P>SOLUTION: The polymer laminate includes a transparent base, having optical isotropy, the shield layer formed on the transparent base and consisting of a transparent resin, and the optical alignment layer, formed on the shield layer and exhibiting alignment capability for liquid crystal molecules by irradiation with light. The polymer laminate, including a polymer compound having an isocyanuric acid skeleton, is provided to the shielding layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polymer laminate and a retardation plate used for liquid crystal display devices and the like.

  The liquid crystal display device has features such as power saving, light weight, thinness, and the like, and has rapidly spread in recent years in place of the conventional CRT display. The liquid crystal display element that constitutes a general liquid crystal display device has a configuration in which a liquid crystal cell is placed between two polarizing plates that are in a crossed Nicols relationship. By applying a voltage to the liquid crystal cell, monochrome display can be switched. A mechanism for displaying video.

  The liquid crystal cell has a configuration in which liquid crystalline compounds having optical anisotropy are regularly arranged between two glass substrates. Since liquid crystalline compounds exhibit refractive index anisotropy (birefringence) in which the refractive index varies depending on the direction, when the liquid crystal display element is viewed from an oblique direction, a display such as a decrease in contrast or a change in color tone is displayed. Quality degradation occurs. For this reason, there is a problem that the viewing angle is narrow as a problem peculiar to the liquid crystal display device.

  A phase difference plate is generally used as means for improving the viewing angle problem of liquid crystal display devices. The phase difference plate has a refractive index anisotropy like liquid crystal molecules, and a liquid crystal display element is provided with a phase difference plate having a predetermined birefringence according to the type of liquid crystal cell. It has a function to cancel the refractive index anisotropy of the functional compound. By using such a retardation plate, it is possible to compensate for the optical anisotropy inherent in the liquid crystal display element and to exhibit excellent viewing angle characteristics.

  Examples of the general retardation plate include those using a uniaxially stretched film or liquid crystal. A retardation plate using liquid crystal has an advantage that since the refractive index anisotropy is large (high birefringence) compared to a uniaxially stretched film, there are many types of liquid crystal display elements that can be used and the application range is wide.

  In such a phase difference plate using liquid crystal, an alignment layer for aligning liquid crystal is an essential constituent element. Therefore, an alignment layer is formed on a transparent substrate, and liquid crystal molecules are arranged on the alignment layer. It is common to have an optically anisotropic layer. As the alignment layer, a rubbing film or a photo-alignment film is generally used. However, the photo-alignment film has an advantage that it is easy to uniformly process a large area and that the alignment direction can be precisely adjusted. Further, since the photo-alignment film has the advantage of not generating static electricity or dust like the rubbing film, it is particularly useful to use the photo-alignment film for a high-quality retardation plate.

  Here, since the retardation plate is used to improve the viewing angle characteristics of the liquid crystal display device, it is necessary to uniformly arrange the liquid crystals in the retardation plate using liquid crystals. However, when the transparent substrate contains, for example, a compound such as an ultraviolet absorber, an optical property developing agent or a plasticizer, these compounds move to the surface of the transparent substrate over time, and further from the transparent substrate to the alignment layer. Further, there is a problem that the liquid crystal alignment of the optically anisotropic layer is disturbed by moving to the optically anisotropic layer on the alignment layer. Such a problem tends to become remarkable particularly in a high temperature and high humidity atmosphere. Patent Document 1 proposes that the alignment film is provided with a function as a shielding layer that suppresses the movement of the compound from the transparent substrate. Thus, imparting a function as a shielding layer to the alignment film is an effective means when using a rubbing film capable of relatively increasing the film thickness. However, there is a problem that it cannot be applied when a photo-alignment film is used as the alignment film.

JP 2003-14935 A

  The present invention has been made in view of the above problems, and is a polymer laminate having a function as a photo-alignment film for aligning liquid crystals and a function as a shielding layer, and an optically anisotropic layer is provided. The main object of the present invention is to provide a polymer laminate capable of obtaining a retardation plate that is free from alignment disorder of liquid crystal molecules and has excellent temporal stability when laminated to form a retardation plate. .

In order to achieve the above object, the present invention provides a transparent base material, a shielding layer formed on the transparent base material and made of a transparent resin, and formed on the shielding layer. A polymer laminate having a photo-alignment layer showing
Provided is a polymer laminate, wherein the shielding layer includes a polymer compound having an isocyanuric acid skeleton.

  According to the present invention, when the transparent base material has a shielding layer made of a transparent resin on the transparent base material, the transparent base material contains a compound such as an ultraviolet absorber, an optical property developing agent, or a plasticizer. Even so, such a compound can be prevented from moving from the transparent substrate to the alignment layer or the optical functional layer over time. That is, according to the present invention, since the shielding layer has a function of suppressing the movement of the compound from the transparent substrate, for example, it has liquid crystal molecules regularly arranged on the polymer laminate according to the present invention. When an optically anisotropic layer is formed to form a retardation plate, it is possible to suppress the disorder of the alignment of liquid crystal molecules by the above compound, and it is possible to obtain a retardation plate having excellent temporal stability. .

  Moreover, according to this invention, affinity with the photo-alignment layer formed on a shielding layer can be improved by including the high molecular compound which has an isocyanuric acid frame | skeleton in the said shielding layer. Therefore, according to the present invention, a uniform and uniform photo-alignment layer can be easily provided on the shielding layer. For example, an optically anisotropic layer is formed on the polymer laminate according to the present invention. When the retardation plate is used, it is possible to prevent liquid crystal molecule alignment troubles due to unevenness of the photo-alignment layer, and to obtain a high-quality retardation plate.

  Furthermore, according to this invention, the adhesiveness of a transparent base material and a shielding layer can be improved by including the high molecular compound which has an isocyanuric acid frame | skeleton in the said shielding layer.

  In the present invention, the polymer compound having an isocyanuric acid skeleton preferably includes a polymer of monomers of isocyanuric acid acrylates. This is because a polymer compound having an isocyanuric acid skeleton can be easily formed by polymerizing monomers of isocyanuric acid acrylates.

  In the present invention, the polymer compound having an isocyanuric acid skeleton is preferably a polymer of a monomer of isocyanuric acid acrylates and a polyfunctional (meth) acrylate monomer. By using the polymer compound having the isocyanuric acid skeleton as a polymer of a monomer of isocyanuric acid acrylates and a polyfunctional (meth) acrylate monomer, the compound is prevented from moving from the transparent substrate to the shielding layer. This is because the function can be improved.

  In the present invention, the constituent material of the photo-alignment layer is preferably made of a photoreactive material that causes a photodimerization reaction. This is because, by using a photoreactive material that causes a photodimerization reaction as the constituent material of the photoalignment layer, a more uniform and uniform photoalignment layer can be formed on the shielding layer.

  Moreover, in this invention, it is preferable that the said transparent base material is a triacetyl cellulose film. Since the triacetyl cellulose film is a transparent substrate excellent in optical isotropy, the optical properties of the polymer laminate of the present invention can be improved by using triacetyl cellulose for the transparent substrate. Because it can.

  Furthermore, the present invention provides a phase difference plate having an optically anisotropic layer on the photo-alignment layer of the polymer laminate.

Since the shielding layer constituting the polymer laminate has a function of suppressing the movement of the compound from the transparent base material, according to the present invention, the retardation property of the optically anisotropic layer is exerted by the action of the compound. Therefore, it is possible to obtain a retardation plate having excellent temporal stability.
Further, since the shielding layer constituting the polymer laminate described above contains a polymer compound having an isocyanuric acid skeleton, a homogeneous and uniform photo-alignment layer can be easily provided on the shielding layer. According to the present invention, for example, in the case of a configuration having liquid crystal molecules in which optically anisotropic layers are regularly arranged, it is possible to prevent alignment failure of liquid crystal molecules due to unevenness of the photo-alignment layer, and to achieve high quality. A phase difference plate can be obtained.

  According to the present invention, when a phase difference plate is prepared using the polymer laminate according to the present invention, an effect is obtained that a phase difference plate having excellent temporal stability can be obtained, and a photo-alignment layer There is an effect that it is possible to obtain a high-quality retardation plate free from liquid crystal molecule alignment hindrance caused by the unevenness.

  Hereinafter, the polymer laminate of the present invention and the retardation plate using the same will be described in detail.

A. Polymer laminate First, the polymer laminate of the present invention will be described.
The polymer laminate of the present invention comprises a transparent base material, a shielding layer formed on the transparent base material and made of a transparent resin, and formed on the shielding layer and exhibiting the ability to align liquid crystal molecules by light irradiation. A polymer laminate having an alignment layer, wherein the shielding layer includes a polymer compound having an isocyanuric acid skeleton.

  The polymer laminate of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of the polymer laminate of the present invention. As shown in FIG. 1, a polymer laminate 11 of the present invention is formed on a transparent base material 1, a shielding layer 2 formed on the transparent base material 1 and made of a transparent resin, and the shielding layer 2. And a photo-alignment layer 3 that exhibits the alignment ability of liquid crystal molecules by light irradiation.

  Even if the polymer laminate of the present invention has a shielding layer made of a transparent resin on a transparent substrate, the transparent substrate contains a compound such as an ultraviolet absorber or a plasticizer. Such a compound can be prevented from moving to the photo-alignment layer or an optically anisotropic layer described later over time.

  A transparent substrate used for a liquid crystal display element constituting a liquid crystal display device needs to have predetermined physical properties such as mechanical strength, curl characteristics, optical characteristics, and surface physical properties. In order to achieve these physical properties, the transparent base material used in the liquid crystal display element has an ultraviolet absorber that absorbs ultraviolet rays and improves the durability of the base material, in order to achieve a predetermined mechanical strength (such as elastic modulus). In general, a plasticizer and a compound such as an optical property developing agent for expressing desired optical properties are included. The use of these compounds has an advantage that various physical properties of a transparent substrate used in a liquid crystal display element can be arbitrarily adjusted. However, since such compounds are generally low-molecular compounds, they are transparent over time. There is a problem of moving from the substrate to another layer in contact with the transparent substrate. This phenomenon is particularly remarkable in a high temperature and high humidity atmosphere.

For this reason, for example, when a transparent substrate containing the above compound is used for a retardation plate having an optically anisotropic layer containing regularly arranged liquid crystal molecules, the compound is optically different from the transparent substrate. When moved to the isotropic layer, the above-described compound disturbs the regular arrangement of the liquid crystal molecules, and there is a problem that the temporal stability of the retardation plate is impaired.
However, according to the polymer laminate of the present invention, since the shielding layer has a function of suppressing the movement of the compound from the transparent substrate, a retardation plate having excellent temporal stability can be obtained.

  Moreover, according to this invention, affinity with the photo-alignment layer formed on a shielding layer can be improved by including the high molecular compound which has an isocyanuric acid frame | skeleton in the said shielding layer.

When creating a retardation film using the polymer laminate of the present invention, in order to regularly arrange liquid crystal molecules on the photo-alignment layer, a uniform and uniform photo-alignment layer is formed on the shielding layer. Is essential. This is because if there is unevenness in the photo-alignment film, it will hinder the regular alignment of liquid crystal molecules and impair the quality of the retardation plate. In order to form such a homogeneous and uniform photo-alignment layer, it is effective to improve the affinity of the photo-alignment layer with respect to the shielding layer surface.
According to the present invention, by including a polymer compound having an isocyanuric acid skeleton in the shielding layer, it is possible to improve the affinity with the photo-alignment layer formed on the shielding layer. A photo-alignment layer having no surface can be easily provided. Therefore, according to the polymer laminate of the present invention, it is possible to obtain a high-quality retardation plate that is free from alignment disorder of liquid crystal molecules due to unevenness of the photo-alignment layer.

  Furthermore, according to this invention, the adhesiveness of a transparent base material and a shielding layer can be improved by including the high molecular compound which has an isocyanuric acid frame | skeleton in the said shielding layer. Therefore, for example, when an optically anisotropic layer is formed on the polymer laminate of the present invention to form a retardation plate, it is possible to prevent delamination during cutting and the like, and a retardation with excellent processability A board can be obtained.

  Hereinafter, each structure of such a polymer laminated body is demonstrated.

1. Shielding layer First, the shielding layer used in the present invention will be described. The shielding layer used in the present invention is formed on the transparent substrate and is made of a transparent resin containing a polymer compound having an isocyanuric acid skeleton.

(1) Polymer compound having isocyanuric acid skeleton The shielding layer is made of a transparent resin containing a polymer compound having an isocyanuric acid skeleton (hereinafter simply referred to as a polymer compound). Hereinafter, the polymer compound constituting the shielding layer will be described.

  The polymer compound is not particularly limited as long as it contains a polymer compound having an isocyanuric acid skeleton, but is preferably a curable resin. This is because a denser shielding layer can be formed by using a curable resin.

  The curable resin is not particularly limited as long as it is cured by supplying energy from outside the system, such as an actinic radiation curable resin curable by actinic radiation or a thermosetting resin curable by heat. However, an actinic radiation curable resin that cures with actinic radiation is preferable. For example, when a thermosetting resin is used, there is a risk that the quality of the shielding layer may be impaired due to thermal fluctuations during the curing process, but in the case of an actinic radiation curable resin, there are few such advantages. It is. Here, the actinic radiation refers to radiation that can supply activation energy necessary for the polymerization reaction of the monomer by irradiating the monomer of the curable resin.

  Examples of the actinic radiation curable resin include a photocurable resin that is cured by light irradiation and an electron beam curable resin that is cured by electron beam irradiation. Among these, a photocurable resin is preferable. This is because the photocurable resin is widely used in other fields and is already established, and thus can be applied to the present invention.

  Examples of the photo-curable resin include photo-curable resins that are cured by ultraviolet light or visible light. Among them, light having a wavelength of 150 to 500 nm, preferably 250 to 450 nm, more preferably 300 to 400 nm. An ultraviolet curable resin that cures when irradiated with is preferable. This is because the use of an ultraviolet curable resin is useful in terms of the ease of the light irradiation device and the like.

  The polymer compound is not particularly limited as long as it has an isocyanuric acid skeleton, but preferably contains a polymer of monomers of isocyanuric acid acrylates. This is because a polymer compound having an isocyanuric acid skeleton according to the present invention can be easily formed by polymerizing monomers of isocyanuric acid acrylates.

  Examples of monomers of isocyanuric acid acrylates that can be suitably used in the present invention include compounds (1) to (3) represented by the following chemical formulas.

In the compounds (1) to (3), R ^a , R ^b , and R ^c are not particularly limited, but are preferably a lower hydrocarbon chain having 1 to 12 carbon atoms, More preferred is a lower hydrocarbon chain of 6. R ^a , R ^b , and R ^c do not need to be the same, and can be arbitrarily selected according to the use of the polymer laminate of the present invention, but are preferably all the same. This is because there is an advantage in that the synthesis of the monomer is facilitated.

  In the present invention, any of the compounds (1) to (3) can be preferably used, but the compound (2) or (3) is more preferably used. This is because by using the compound (2) or (3) having two or more acryloyl groups in the molecule, a three-dimensional network can be formed and a denser shielding layer can be formed.

  The polymer compound is preferably composed of a polymer of the aforementioned isocyanuric acid acrylate monomers and other actinic radiation curable monomers. By making a polymer of a monomer of isocyanuric acid acrylates and other actinic radiation curable monomers, the shielding layer has excellent shielding properties to prevent the compound from moving from the transparent substrate. Because you can. In the present invention, the actinic radiation curable monomer may be one kind or a mixture of two or more kinds.

  The other actinic radiation curable monomer is not particularly limited as long as it is cured by irradiation with actinic radiation, and among them, a polyfunctional (meth) acrylate monomer is preferable. This is because, by using a polymer with a polyfunctional (meth) acrylate monomer, the shielding layer can be made excellent in shielding properties that suppress the migration of the compound from the transparent substrate.

Specific examples of such polyfunctional (meth) acrylate monomers include ethylene glycol (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, and polyethylene glycol. Di (meth) acrylate, polypropylene glycol di (meth) acrylate, hexane di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) Acrylate, 1,4-butanediol diacrylate, pentaerythritol (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythris Alkyl (meth) acrylates such as tall tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, Examples include hydroxy group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, and epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate. It is not limited to this.

(2) Shielding layer The shielding layer in this invention consists of transparent resin containing the high molecular compound which has the said isocyanuric acid frame | skeleton.

  The transparent resin forming the shielding layer in the present invention is not particularly limited as long as it contains a polymer compound having an isocyanuric acid skeleton, and the polymer compound may be formed from only the polymer compound. And a mixture of other polymer compounds.

The shielding layer of the present invention may have a single layer structure or a structure in which a plurality of layers are stacked depending on the use of the polymer laminate. In the case of a single layer, the shielding layer may uniformly contain a polymer compound having an isocyanuric acid skeleton, or may have a concentration gradient. As a specific example in the case of having a concentration gradient, for example, in the shielding layer 2 in FIG. 1, the concentration of the polymer compound having an isocyanuric acid skeleton is increased on the surface on the photo-alignment layer 3 side, and the transparent substrate 1 Although the aspect which makes the surface of the side low can be illustrated, it is not this limitation.
Here, the concentration gradient means that the concentration of the polymer compound having an isocyanuric acid skeleton differs between any two points in the shielding layer. The concentration gradient in the present invention includes the case where a polymer compound having an isocyanuric acid skeleton is not present in a part of the region in the shielding layer.
As a specific example in the case where the shielding layer has a configuration in which a plurality of layers are stacked, an embodiment in which a plurality of layers having different contents of the polymer compound having an isocyanuric acid skeleton are stacked can be exemplified. For example, the shielding layer 2 in FIG. 1 has a two-layer structure, a layer having a high content of a polymer compound having an isocyanuric acid skeleton is disposed on the photo-alignment layer 3 side, and a layer having a low content is disposed on the transparent substrate 1 side. Although the structure arrange | positioned to can be illustrated, it is not this limitation.

  The transmittance of the shielding layer used in the present invention is preferably 80% or more in the visible light region, and more preferably 90% or more. Here, the transmittance can be measured by JIS K7361-1 (Testing method for total light transmittance of plastic-transparent material).

  The thickness of the shielding layer used in the present invention may be arbitrarily determined within a range in which the shielding layer can suppress the migration of the compound from the transparent substrate, depending on the type of transparent resin constituting the shielding layer. However, it is usually preferably in the range of 0.5 μm to 20 μm, particularly preferably in the range of 1 μm to 15 μm, and particularly preferably in the range of 2 μm to 10 μm. This is because if the thickness of the shielding layer is smaller than the above range, the shielding property may be lowered, and if it is larger than the above range, it may be difficult to obtain a smooth surface.

(3) Forming method of shielding layer The forming method of the shielding layer used in the present invention is not particularly limited as long as it is a method capable of obtaining flatness capable of uniformly laminating the photo-alignment layer. Although there is not, the method of apply | coating the composition for shielding layer formation on the said transparent base material is preferable. This is because such a method can easily form a shielding layer having excellent planarity.

a. Composition for shielding layer formation As the composition for shielding layer formation, a melt of a transparent resin containing the above-described polymer compound having an isocyanuric acid skeleton, and a solution containing the above-mentioned polymer compound having an isocyanuric acid skeleton, Although the solution containing the monomer of isocyanuric acid acrylates can be mentioned, the solution containing the monomer of isocyanuric acid acrylates is more preferable. The solution containing the monomer of the isocyanuric acid acrylates preferably contains a polyfunctional (meth) acrylate monomer. This is because the use of such a composition for forming a shielding layer has an advantage that the method for forming the shielding layer is facilitated.

  Such a composition for forming a shielding layer usually comprises a monomer of isocyanuric acid acrylates, a polyfunctional (meth) acrylate monomer, and a solvent, and may contain a photopolymerization initiator and other compounds as necessary. Good. Hereinafter, each of these configurations will be described.

(Monomer of isocyanuric acid acrylates)
Since the monomer of isocyanuric acid acrylates contained in the composition for forming a shielding layer is the same as that described in the above section “(1) Polymer compound having isocyanuric acid skeleton”, description thereof is omitted here. To do.

  The content of the monomer of isocyanuric acrylates in the composition for forming a shielding layer can impart an affinity necessary for providing a uniform and uniform photo-alignment layer on the surface of the shielding layer. Although it is not particularly limited as long as it is in the range, it is usually preferably in the range of 5% by mass to 95% by mass, particularly in the range of 10% by mass to 90% by mass in the solid content of the composition for forming a shielding layer. In particular, the range of 20% by mass to 80% by mass is preferable. When the concentration is higher than the above range, the shielding property of the compound from the transparent substrate may be lowered. When the concentration is lower than the above range, the affinity necessary for providing a uniform and non-uniform photo-alignment layer. This is because it may not be possible to express.

(Polyfunctional (meth) acrylate monomer)
The polyfunctional (meth) acrylate monomer contained in the composition for forming a shielding layer is the same as that described in the above-mentioned section “(1) Polymer compound having an isocyanuric acid skeleton”. Is omitted.

  The content of the polyfunctional (meth) acrylate monomer in the composition for forming a shielding layer is particularly limited as long as it can provide the shielding layer with a shielding property that suppresses the movement of the compound from the transparent substrate. Usually, the solid content of the composition for forming a shielding layer is preferably within a range of 5% by mass to 95% by mass, particularly preferably within a range of 10% by mass to 90% by mass, and more preferably 20% by mass. Within the range of -80 mass% is preferable.

(solvent)
As a solvent used for the said composition for shielding layer formation, if the monomer of isocyanuric acid acrylates can be melt | dissolved in a desired density | concentration, it can use without being specifically limited. Specifically, alcohols such as methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol; terpenes such as α- or β-terpineol; acetone, methyl ethyl ketone, cyclohexanone, N-methyl-2-pyrrolidone, etc. Ketones; aromatic hydrocarbons such as toluene, xylene, tetramethylbenzene; cellosolve, methyl cellosolve, ethyl cellosolve, carbitol, methyl carbitol, ethyl carbitol, butyl carbitol, propylene glycol monomethyl ether, propylene glycol monoethyl Ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol Glycol ethers such as ethyl monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl Acetic acid esters such as ether acetate can be exemplified. These solvents can be used alone or as a mixed solvent of two or more.

(Photopolymerization initiator)
It is preferable to add a photopolymerization initiator to the composition for forming a shielding layer. This is because by adding the photopolymerization initiator, the ultraviolet curable resin can be rapidly cured, which is advantageous in terms of productivity. As the photopolymerization initiator in the present invention, a radical photopolymerization initiator that can be activated by ultraviolet light, for example, ultraviolet light of 365 nm or less is used. Specifically, benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamine) benzophenone, 4,4-bis (diethylamine) benzophenone, α-amino-acetophenone, 4,4-dichlorobenzophenone, 4- Benzoyl-4-methyldiphenyl ketone, dibenzyl ketone, fluorenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, p-tert-butyldichloro Acetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyldimethyl ketal, benzylmethoxyethyl acetal, benzoin methyl ether, Nzoin butyl ether, anthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, anthrone, benzanthrone, dibenzsuberon, methyleneanthrone, 4-azidobenzylacetophenone, 2,6-bis (p-azidobenzylidene ) Cyclohexane, 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone, 2-phenyl-1,2-butadion-2- (o-methoxycarbonyl) oxime, 1-phenyl-propanedione-2- ( o-ethoxycarbonyl) oxime, 1,3-diphenyl-propanetrione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxy-propanetrione-2- (o-benzoyl) oxime, Michler's ketone 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, naphthalenesulfonyl chloride, quinoline Sulfonyl chloride, n-phenylthioacridone, 4,4-azobisisobutyronitrile, diphenyl disulfide, benzthiazole disulfide, triphenylphosphine, camphorquinone, Adeka N1717, carbon tetrabromide, tribromophenyl sulfone, Examples thereof include a combination of a photoreductive dye such as benzoin peroxide, eosin and methylene blue with a reducing agent such as ascorbic acid or triethanolamine. In this invention, these photoinitiators can be used 1 type or in combination of 2 or more types.

  The content of such a photopolymerization initiator is preferably in the range of 0.5 to 30% by mass, particularly in the range of 1 to 10% by mass in the solid content of the composition for forming a shielding layer.

(Other compounds)
The composition for forming a shielding layer may contain other compounds as necessary. The other compound is not particularly limited as long as it does not impair the shielding property of the shielding layer and the affinity necessary for laminating the photo-alignment layer.

b. Forming method of shielding layer The coating method of the composition for forming a shielding layer on the transparent substrate is a method that can achieve flatness capable of uniformly laminating the photo-alignment layer, in particular. It is not limited. Specific examples include spin coating, roll coating, printing, dipping and pulling, curtain coating, die coating, casting, and bar coating, but are not limited thereto. Moreover, the single layer application | coating which apply | coats a single layer, or the multilayer application | coating which apply | coats several layers simultaneously may be sufficient.

  The thickness of the coating film of the composition for forming a shielding layer is not particularly limited as long as the flatness capable of laminating a homogeneous photo-alignment layer can be achieved, but is usually 1 μm to 2000 μm. The range of 10 μm to 1000 μm is more preferable, and the range of 50 μm to 500 μm is more preferable. If the thickness is less than the above range, the flatness of the shielding layer may be impaired. If the thickness is more than the above range, the drying load of the solvent increases and the productivity is lowered.

2. Next, the photo-alignment layer used in the present invention will be described. The photo-alignment layer used in the present invention is a layer formed on the shielding layer and exhibiting the alignment ability of liquid crystal molecules by light irradiation. According to this invention, since the said shielding layer is excellent in affinity with a photo-alignment layer, it is possible to make a photo-alignment layer homogeneous and uniform. Therefore, for example, when an optically anisotropic layer is formed on the photo-alignment layer used in the present invention, it is possible to prevent liquid crystal molecule alignment disorder due to unevenness of the photo-alignment layer, and a high-quality phase difference. A board can be obtained.

  Hereinafter, such a photo-alignment layer will be described in detail.

(1) Material constituting photo-alignment layer (photoreactive material)
Since the photo-alignment layer used in the present invention is a layer showing the alignment ability of liquid crystal molecules by light irradiation, the material constituting the photo-alignment layer is an anisotropy necessary for aligning liquid crystal molecules by light irradiation. There is no particular limitation as long as it is a photoreactive material capable of imparting.
Such photoreactive materials include a photodimerization material that exhibits the above anisotropy by causing a photodimerization reaction, and a photoisomerization material that exhibits the above anisotropy by causing a photoisomerization reaction. In the present invention, a photodimerization material that exhibits the above anisotropy by causing a photodimerization reaction is more preferable. This is because by using the photodimerization type material, it is possible to form a more uniform and non-uniform photo-alignment layer on the shielding layer. Here, the photodimerization reaction refers to a reaction in which a radical polymerization reaction occurs by light irradiation and two molecules are polymerized.

  The wavelength region of light that causes the photodimerization reaction of the photodimerization material is preferably in the range of 10 nm to 400 nm, and more preferably in the range of 250 nm to 380 nm. This is because it is advantageous in the availability of a light source for light irradiation.

  In addition, the photodimerization type material is not particularly limited as long as it is a material that can impart anisotropy to the photoalignment layer by a photodimerization reaction, but has a radical polymerizable functional group, And it is preferable that the photodimerization reactive compound which has the dichroism which makes absorption differ with polarization directions is included. This is because by radical polymerization of the reaction site oriented in the polarization direction, the orientation of the photodimerization reactive compound is stabilized and anisotropy can be easily imparted to the photo-alignment film. In addition, such a photodimerization reactive compound has an advantage of high exposure sensitivity and a wide range of material selection.

  Examples of the photodimerization reactive compound having such characteristics include a dimerization reactive polymer having at least one reactive site selected from a cinnamic acid ester, coumarin, quinoline, and chalcone group as a side chain. Among these, the photodimerization reactive compound is preferably a dimerization reactive polymer containing any one of cinnamate ester, coumarin and quinoline as a side chain. This is because anisotropy can be easily imparted to the first photo-alignment film by radical polymerization of α, β unsaturated ketone double bonds aligned in the polarization direction as reaction sites.

  The dimerization reactive polymer containing a cinnamate ester as the side chain is irradiated with polarized light, for example, a cinnamate ester between adjacent molecules oriented in the polarization direction as shown in the following formula undergoes radical polymerization, A dimer of either formula (A) or (B) below is produced. In this way, the dimerization reactive polymer is oriented parallel to the polarization direction.

  The main chain of the dimerization reactive polymer is not particularly limited as long as it is generally known as a polymer main chain, but the reaction site of the side chain such as an aromatic hydrocarbon group is not limited. It is preferable that it does not have a substituent containing a lot of π electrons that hinders mutual interaction.

  The weight average molecular weight of the dimerization reactive polymer is not particularly limited, but is preferably in the range of 5,000 to 40,000, more preferably in the range of 10,000 to 20,000. It is. The weight average molecular weight can be measured by a gel permeation chromatography (GPC) method. If the weight-average molecular weight of the dimerization reactive polymer is too small, it may not be possible to impart appropriate anisotropy to the photo-alignment layer. On the other hand, if it is too large, a smooth photo-alignment layer may not be formed.

  As a dimerization reactive polymer, the compound represented by following formula (4) can be illustrated.

In the above formula (4), M ¹ and M ² each independently represent a monomer unit of a monopolymer or a copolymer. Examples thereof include ethylene, acrylate, methacrylate, 2-chloroacrylate, acrylamide, methacrylamide, 2-chloroacrylamide, styrene derivatives, maleic acid derivatives, and siloxane. M ² may be acrylonitrile, methacrylonitrile, methacrylate, methyl methacrylate, hydroxyalkyl acrylate or hydroxyalkyl methacrylate. x and y represent the molar ratio of each monomer unit in the case of a copolymer, and are numbers satisfying 0 <x ≦ 1, 0 ≦ y <1 and satisfying x + y = 1, respectively. It is. n represents an integer of 4 to 30,000. D ¹ and D ² represent spacer units.

R ^{21 _{is, -A- (Z 1 -B) z}} -Z 2 - is a group represented ^{by, R 22} is _{^{-A- (Z 1 -B) Z -Z}} 3 - is a group represented by . Here, A and B are each independently a covalent single bond, pyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,4-cyclohexylene, 1,3-dioxane-2,5- Diyl or 1,4-phenylene which may have a substituent is represented. Z ¹ and Z ² are each independently a covalent single bond, —CH ₂ —CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CONR—, —RNCO—, —COO— or — Represents OOC-. R is a hydrogen atom or a lower alkyl group, and Z ³ is a hydrogen atom or an alkyl or alkoxy having 1 to 12 carbon atoms, which may have a substituent, cyano, nitro, or halogen. z is an integer of 0-4. C represents a photodimerization reaction site, and examples thereof include cinnamic acid ester, coumarin, quinoline, chalcone group, cinnamoyl group and the like. j and k are each independently 0 or 1.

  As such a dimerization reactive polymer, More preferably, the compound represented by a following formula can be mentioned.

  Among the dimerization reactive polymers, compounds (5) to (8) represented by the following formulas are particularly preferable.

(2) Photo-alignment layer The thickness of the photo-alignment layer used in the present invention is not particularly limited as long as the photo-alignment property with respect to the liquid crystal molecules can be obtained according to the type of material constituting the photo-alignment film. It is preferably in the range of ˜200 nm, more preferably in the range of 3 nm to 100 nm. This is because if the thickness of the photo-alignment layer is thinner than the above range, sufficient optical alignment may not be obtained, and if the thickness is larger than the above range, the cost may be disadvantageous.

(3) Formation method of photo-alignment layer The formation method of the photo-alignment layer used in the present invention is not particularly limited as long as it is a method capable of forming a smooth layer having a uniform film thickness, but the photoreactive material is used as a solvent. A method of applying the dissolved composition for forming a photo-alignment layer on the shielding layer is preferable. This is because according to such a method, a photo-alignment layer having excellent planarity can be easily formed.

a. Composition for forming photo-alignment layer The composition for forming a photo-alignment layer is usually composed of a photoreactive material and a solvent, and may contain other compounds as necessary. Hereinafter, such a composition for forming a photo-alignment layer will be described.

(Photoreactive material)
The photoreactive material used for the photoalignment layer forming composition is the same as that described in the above section “(1) Material constituting photoalignment layer (photoreactive material)”. The description in is omitted.

  The concentration of the photoreactive material in the composition for forming a photoalignment layer is preferably in the range of 0.05% by mass to 10% by mass, and in the range of 0.2% by mass to 2% by mass. It is more preferable. If the concentration is higher than the above range, the planarity of the photo-alignment layer may be impaired, and if the concentration is lower than the above range, the drying load of the solvent increases and the productivity may decrease. .

(solvent)
As a solvent used for the composition for forming a photo-alignment layer, a general organic solvent can be used.

  Moreover, as another compound used for the said composition for photo-alignment layer formation, a polymerization initiator, a polymerization inhibitor, etc. are mentioned. The polymerization initiator or polymerization inhibitor may be appropriately selected from those generally used depending on the type of the photoreactive material. Further, the content of the polymerization initiator or polymerization inhibitor is preferably in the range of 0.001% by mass to 20% by mass with respect to the photoreactive material, and in the range of 0.1% by mass to 5% by mass. More preferably, it is within. Furthermore, you may use a silane coupling agent as said additive according to the use of the polymer laminated body concerning this invention.

b. Forming method of photo-alignment layer As a coating method of such a composition for forming a photo-alignment layer, for example, spin coating, roll coating, spray coating, air knife coating, slot die coating, flexographic printing, and the like can be used.

3. Transparent base material Next, the transparent base material used for this invention is demonstrated. The transparency of the transparent substrate used in the present invention can achieve desired optical properties depending on the use of the polymer laminate and the types of the shielding layer, the photo-alignment layer, and the optically anisotropic layer. Can be arbitrarily used, but in particular, the transmittance in the visible light region is preferably 80% or more, and more preferably 90% or more. This is because if the transmittance is low, the selection range of the constituent materials of the shielding layer and the photo-alignment layer may be narrowed. Here, the transmittance of the transparent substrate can be measured according to JIS K7361-1 (a test method for the total light transmittance of a plastic transparent material).

The transparent substrate used in the present invention preferably has optical isotropy. This is because by using a transparent substrate having optical isotropy, the polymer laminate of the present invention can be adapted to a wide range of applications.
The optical isotropy of the transparent substrate used in the present invention is desired depending on the use of the polymer laminate and the types of materials constituting the shielding layer, the photo-alignment layer, and the optically anisotropic layer. In particular, the retardation value (Re) is preferably in the range of 0 nm to 100 nm, more preferably in the range of 0 nm to 50 nm, and in the range of 0 nm to 10 nm. Is more preferable. This is because by using such a transparent substrate, the range of selection of the use of the polymer laminate and the types of the shielding layer, the photo-alignment layer, and the optically anisotropic layer can be expanded. Here, the retardation value (Re) is nx the refractive index in the slow axis direction (the direction in which the refractive index is maximum) of the transparent substrate, and the fast axis direction (the refractive index is at the minimum) in the transparent substrate. (Direction) is a value represented by Re = (nx−ny) × d, where ny is the refractive index and d (nm) is the thickness of the transparent substrate.

  The thickness of the transparent substrate used in the present invention is not particularly limited as long as it has the necessary self-supporting property depending on the use of the polymer laminate, but is preferably in the range of 10 μm to 500 μm, and preferably 40 μm to 300 μm. The range is more preferable, and the range of 60 μm to 150 μm is more preferable. This is because if the thickness is less than the above range, the self-supporting property of the polymer laminate is lowered, and for example, the self-supporting property required for use in a retardation plate may not be obtained. Moreover, when it is thicker than the above range, when cutting the polymer laminate, there is a case where processing waste increases and wear of the cutting blade is accelerated.

  The transparent substrate used in the present invention may be a rigid material having flexibility or a flexible material having no flexibility, but it is preferable to use a flexible material. By using a flexible material, the production process of the polymer laminate of the present invention can be a roll-to-roll process, and the polymer laminate of the present invention can be made excellent in productivity.

  As the flexible material, for example, polycarbonates, polyesters, cellulose derivatives, norbornene resins and the like can be arbitrarily used depending on the use of the polymer laminate, and among them, it is preferable to use those made of cellulose derivatives. . This is because the cellulose derivative is particularly excellent in optical isotropy, so that a polymer laminate excellent in optical properties can be obtained.

  As the cellulose derivative, a cellulose ester is preferably used, and among the cellulose esters, cellulose acylates are preferably used. This is because cellulose acylates are advantageous in terms of availability because they are widely used industrially.

  As the cellulose acylates, acetyl cellulose is preferable, and triacetyl cellulose having an average acetylation degree of 57.5 to 62.5% (substitution degree: 2.6 to 3.0) is most preferable. Because many types of such triacetyl cellulose are industrially used, it is possible to select a triacetyl cellulose suitable for the use of the polymer laminate. Here, the degree of acetylation means the amount of bound acetic acid per unit weight of cellulose. The degree of acetylation can be determined by measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like).

  The triacetyl cellulose may contain a compound such as an ultraviolet absorber, an optical property developing agent, or a plasticizer. In the present invention, since the shielding layer formed on the transparent substrate has a function of suppressing the movement of such a compound from the transparent substrate, for example, on the polymer laminate according to the present invention, a rule When a phase difference plate is formed by forming an optically anisotropic layer having regularly aligned liquid crystal molecules, it is possible to prevent the regular alignment of the liquid crystal molecules from being disturbed by the above compound, and stability over time This is because an excellent retardation film can be obtained.

5. Polymer Laminate The film thickness of the polymer laminate of the present invention is appropriately selected depending on the use of the polymer laminate, etc., but is usually preferably in the range of 20 μm to 500 μm, more preferably in the range of 40 μm to 250 μm. The range of 60 μm to 200 μm is more preferable. This is because if the thickness is smaller than the above range, the self-supporting property of the polymer laminate is lowered, and for example, the self-supporting property required when used for a retardation plate may not be obtained. Moreover, when it is thicker than the above range, when cutting the polymer laminate, there is a case where processing waste increases and the cutting blade wears faster.

  The transparency of the polymer laminate of the present invention can be appropriately determined depending on the use of the polymer laminate, etc. Among them, the transmittance in the visible light region is preferably 80% or more, and 90% or more. More preferably. This is because if the transmittance is low, the selection range of the constituent materials for the shielding layer and the photo-alignment layer formed on the transparent substrate is narrowed. Here, the transmittance of the transparent substrate can be measured according to JIS K7361-1 (a test method for the total light transmittance of a plastic transparent material).

B. Next, the retardation plate of the present invention will be described.
The retardation plate of the present invention is characterized by having an optically anisotropic layer on the photo-alignment layer of the polymer laminate.

The retardation plate of the present invention will be described with reference to the drawings. FIG. 2 is a schematic sectional view showing an example of the retardation plate of the present invention. As shown in FIG. 2, the retardation film 12 of the present invention is formed on the transparent base material 1, the shielding base material 2 formed on the transparent base material 1, and made of a transparent resin. A polymer laminate 11 having a photo-alignment layer 3 that exhibits alignment ability of liquid crystal molecules upon irradiation;
And an optically anisotropic layer 4 formed on the photo-alignment layer 3 of the polymer laminate 11.

  Since the polymer laminate has the shielding layer, even when a compound such as an ultraviolet absorber or a plasticizer is contained in the transparent substrate, such a compound may be aligned over time. In addition, since it has a function of preventing movement to the optically anisotropic layer, a retardation plate having excellent temporal stability can be obtained.

  In addition, since the polymer laminate includes a polymer compound having an isocyanuric acid skeleton in the shielding layer, the affinity with the photo-alignment layer formed on the shielding layer can be improved. It is possible to easily provide a uniform and uniform photo-alignment layer. Therefore, by forming an optically anisotropic layer on the polymer laminate, it is possible to prevent alignment disorder of liquid crystal molecules due to unevenness of the photo-alignment layer, and to obtain a high-quality retardation plate. it can.

  Hereinafter, each structure of such a phase difference plate will be described. In addition, since the polymer laminated body used for the phase difference plate of this invention is the same as that of what was described in the term of the said "A. polymer laminated body", description here is abbreviate | omitted.

1. Optically anisotropic layer The optically anisotropic layer in this invention is formed on the photo-alignment layer which the said polymer laminated body has, and shows optical anisotropy.

(1) Structure of optically anisotropic layer The structure of the optically anisotropic layer is not particularly limited as long as the desired optical anisotropy can be achieved. The layer is preferably formed by fixing liquid crystal molecules. This is because the polymer laminate used in the present invention has a photo-alignment layer, so that liquid crystal molecules can be easily aligned. In addition, since the optically anisotropic layer is formed by fixing liquid crystal molecules, the optically anisotropic layer can increase the optical anisotropy per unit thickness. This is because thinning is possible.

  In the case where the optically anisotropic layer used in the present invention is formed by fixing liquid crystal molecules, the liquid crystalline material used for the optically anisotropic layer is a material exhibiting liquid crystallinity at a predetermined temperature. There is no particular limitation as long as it is present. Further, it may be a polymer liquid crystal material having no polymerizability, or may be a polymerizable liquid crystal material.

  As the polymerizable liquid crystal material, any of a polymerizable liquid crystal monomer, a polymerizable liquid crystal oligomer, and a polymerizable liquid crystal polymer can be used. On the other hand, as a polymer liquid crystal material having no polymerizability, since the alignment state of the liquid crystal needs to be constant at the storage or use temperature of the retardation plate, the liquid crystal material having a relatively high temperature that becomes a relatively isotropic phase Are preferably used.

  In the present invention, it is particularly preferable to use a polymerizable liquid crystal material. As described later, the polymerizable liquid crystal material can be polymerized by irradiation with an active irradiation ray or the like to fix the alignment state, so that the liquid crystal can be easily aligned at a low temperature, and This is because the orientation state is fixed during use, so that it can be used regardless of the use conditions such as temperature.

  Among the polymerizable liquid crystal materials, a polymerizable liquid crystal monomer is preferably used. This is because the polymerizable liquid crystal monomer can be easily aligned because it can be aligned at a lower temperature than the polymerizable liquid crystal oligomer and the polymerizable liquid crystal polymer and has high sensitivity at the time of alignment. . As such a polymerizable liquid crystal monomer, those generally used for retardation plates can be used.

  Furthermore, the liquid crystallinity of the polymerizable liquid crystal material used in the present invention is not particularly limited, and examples thereof include nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, and discotic liquid crystal.

  Examples of the polymerizable liquid crystal monomer exhibiting nematic liquid crystallinity include compounds represented by the following chemical formula.

  In the above chemical formula (9), X is hydrogen, alkyl having 1 to 20 carbons, alkenyl having 1 to 20 carbons, alkyloxy having 1 to 20 carbons, alkyloxycarbonyl having 1 to 20 carbons, formyl, carbon It represents an alkylcarbonyl having 1 to 20 carbon atoms, an alkylcarbonyloxy having 1 to 20 carbon atoms, halogen, cyano or nitro. M represents an integer in the range of 2-20.

  Examples of the polymerizable liquid crystal monomer exhibiting cholesteric liquid crystallinity include a compound represented by the above chemical formula (9) or a compound represented by the following chemical formula.

  Furthermore, as a polymerizable liquid crystal material exhibiting discotic liquid crystallinity, for example, a triphenylene-based discotic liquid crystal that can be polymerized as used for forming a WV film (trade name, manufactured by Fuji Photo Film Co., Ltd.), or Examples thereof include compounds represented by the following chemical formula.

  The optically anisotropic layer in the present invention may contain a photopolymerization initiator as necessary. This is because, for example, when a polymerizable liquid crystal material is polymerized by ultraviolet (UV) irradiation, a photopolymerization initiator is usually used to accelerate the polymerization. Examples of the photopolymerization initiator include those described in “1. Since it is the same as what was described in the term of the shielding layer, description here is abbreviate | omitted. Moreover, according to the use of the phase difference plate of this invention, you may contain a silane coupling agent.

(2) Optically anisotropic layer The thickness of the optically anisotropic layer used in the present invention may be determined according to the required optical anisotropy, but is usually in the range of 0.1 μm to 10 μm, It is preferably within a range of 0.3 μm to 6 μm. This is because if the thickness is larger than the above range, an optical anisotropy more than necessary may occur, and if the thickness is smaller than the above range, the predetermined optical anisotropy may not be obtained.

(3) Method for forming optically anisotropic layer The phase layer forming method in the present invention is not particularly limited as long as it is a method capable of forming a smooth layer with a constant film thickness. A method of fixing the liquid crystal after applying the composition for forming the anisotropic layer is preferable. This is because according to such a method, it is possible to easily form a smooth layer having a constant film thickness.

a. Composition for forming an optically anisotropic layer The composition for forming an optically anisotropic layer usually comprises a liquid crystalline material and a solvent, and contains other compounds as necessary. Hereinafter, such a composition for forming an optically anisotropic layer will be described.

(Liquid crystal material)
Since the liquid crystalline material used for the composition for forming an optically anisotropic layer is the same as that described in the section “(1) Configuration of optically anisotropic layer”, description thereof is omitted here. .

  The concentration of the liquid fired material in the composition for forming an optically anisotropic layer depends on the solubility of the liquid crystalline material and the thickness of the target optically anisotropic layer. Is prepared in the range of 0.1 to 40% by mass, preferably 1 to 20% by mass. If the concentration of the solution is too low, it may be difficult to align the liquid crystal. Conversely, if the concentration of the solution is too high, the viscosity of the solution will increase and it may be difficult to form a uniform coating film. is there.

(solvent)
The solvent used in the phase difference phase forming composition is not particularly limited as long as it can dissolve the above-described liquid crystalline material and the like and does not inhibit the alignment ability of the photo-alignment layer. For example, hydrocarbons such as benzene, toluene, xylene, n-butylbenzene, diethylbenzene and tetralin; ethers such as methoxybenzene, 1,2-dimethoxybenzene and diethylene glycol dimethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 2 Ketones such as 1,4-pentanedione; esters such as ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, γ-butyrolactone; 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethylformamide, dimethyl Amide solvents such as acetamide; t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethyleneglycol Alcohols such as hexylene glycol, phenols, phenols such as phenol and parachlorophenol, and one or more cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and ethylene glycol monomethyl ether acetate can be used. . The use of a single type of solvent may result in insufficient solubility of the liquid crystal or the like, and the photo-alignment layer may be eroded as described above. Therefore, this inconvenience can be avoided. Of these solvents, hydrocarbons and glycol monoether acetate solvents are preferred as the sole solvent, and mixed solvents of ethers or ketones and glycol solvents are preferred as the mixed solvent. It is.

(Other compounds)
Furthermore, other compounds can be added to the composition for forming an optically anisotropic layer as long as the object of the present invention is not impaired. Other compounds that can be added include, for example, a polyester (meth) acrylate obtained by reacting a (meth) acrylic acid with a polyester prepolymer obtained by condensing a polyhydric alcohol with a monobasic acid or polybasic acid; a polyol Polyurethane (meth) acrylate obtained by reacting a group and a compound having two isocyanate groups with each other and then reacting the reaction product with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin , Epoxy resins such as novolac type epoxy resins, polycarboxylic acid polyglycidyl esters, polyol polyglycidyl ethers, aliphatic or cycloaliphatic epoxy resins, amine epoxy resins, triphenolmethane type epoxy resins, dihydroxybenzene type epoxy resins, ( Meta) Epoxy obtained by reacting acrylic acid (meth) photopolymerizable compound such as acrylate; photopolymerizable liquid crystal compound having an acryl group or methacryl group and the like. The amount of these compounds added to the composition for forming an optically anisotropic layer is selected within a range that does not impair the object of the present invention. By adding these compounds, the curability of the liquid crystal is improved, the mechanical strength of the resulting optically anisotropic layer is increased, and the stability is improved.

b. Method for forming optically anisotropic layer Examples of methods for applying the composition for forming an optically anisotropic layer onto the polymer laminate include spin coating, roll coating, printing, immersion pulling, curtains, and the like. Examples thereof include a coating method (die coating method), a casting method, a bar coating method, a blade coating method, a spray coating method, a gravure coating method, a reverse coating method, and an extrusion coating method.

  The alignment fixing treatment of the liquid crystalline material is performed by a method that differs depending on the liquid crystalline material used. Specifically, the liquid crystal is divided into a polymerizable liquid crystal material and a polymer liquid crystal material having no polymerizability. Hereinafter, the case of a polymerizable liquid crystal material and the case of a polymer liquid crystal material having no polymerizability will be described separately.

(Polymerizable liquid crystal material)
In the present invention, the alignment fixing treatment of the polymerizable liquid crystal material is carried out by a method of irradiating the coating film made of the composition for forming an optically anisotropic layer containing the polymerizable liquid crystal material with actinic radiation that activates the polymerization. Done.

  The active radiation as used in the field of this invention means the radiation which has the capability to cause superposition | polymerization with respect to polymeric material, If necessary, the photoinitiator may be contained in polymeric material. In addition, about a photoinitiator, 1. above-mentioned "A. polymer laminated body". Since it is the same as what was described in the term of the shielding layer, description here is abbreviate | omitted.

  The actinic radiation is not particularly limited as long as it is a radiation capable of polymerizing the polymerizable liquid crystal material, but usually ultraviolet light or visible light is used from the viewpoint of the ease of the apparatus, and the wavelength. Irradiating light of 150 to 500 nm, preferably 250 to 450 nm, more preferably 300 to 400 nm is used.

  In the present invention, a method of irradiating ultraviolet rays with active radiation to a polymerizable liquid crystal material in which the photopolymerization initiator generates radicals with ultraviolet rays and the polymerizable liquid crystal material undergoes radical polymerization is a preferable method. . This is because the method using ultraviolet rays as actinic radiation is an already established technique, and therefore it can be easily applied to the present invention including the photopolymerization initiator to be used.

  As the light source of this irradiation light, low pressure mercury lamp (sterilization lamp, fluorescent chemical lamp, black light), high pressure discharge lamp (high pressure mercury lamp, metal halide lamp), short arc discharge lamp (super high pressure mercury lamp, xenon lamp, mercury xenon) Lamp). Among these, use of a metal halide lamp, a xenon lamp, a high-pressure mercury lamp, etc. is recommended. The irradiation intensity is appropriately adjusted according to the composition of the polymerizable liquid crystal material and the content of the photopolymerization initiator.

  Such immobilization treatment by irradiation with actinic radiation may be performed under a temperature condition in which the polymerizable liquid crystal material becomes a liquid crystal phase, or may be performed at a temperature lower than the temperature at which the liquid crystal phase becomes. This is because the alignment state of the polymerizable liquid crystal material once in the liquid crystal phase is not disturbed suddenly even if the temperature is lowered thereafter.

(Polymer liquid crystal material without polymerizability)
In the present invention, the alignment immobilization treatment in the case of using a polymer liquid crystal material having no polymerizability is performed by a method of reducing the treatment temperature from the temperature at which the liquid crystal phase is obtained to the temperature at which the solid phase is obtained. By aligning the polymer liquid crystal material with the photo-alignment layer and lowering the processing temperature to a glass temperature in this state, an optically anisotropic layer can be obtained.

2. Retardation plate The thickness of the retardation plate of the present invention is appropriately selected depending on the use and type of the retardation plate, and is usually preferably in the range of 1 μm to 500 μm, more preferably in the range of 5 μm to 250 μm. The range of 20 μm to 150 μm is more preferable.

  The transparency of the retardation plate of the present invention can be appropriately determined depending on the use of the polymer laminate, etc. Among them, the transmittance in the visible light region is preferably 80% or more, and 90% or more. It is more preferable. The transmittance can be measured by JIS K7361-1 (Testing method for total light transmittance of plastic-transparent material).

  The retardation of the retardation plate of the present invention depends on the intended use of the polymer laminate and the type of material constituting the shielding layer, the photo-alignment layer, and the optically anisotropic layer. Although what can achieve a property can be employ | adopted arbitrarily, it is preferable that a retardation value (Re) is the range of 10 nm-3000 nm, The range of 20 nm-1000 nm is more preferable, The range of 50 nm-300 nm is further more preferable.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the technical idea described in the claims of the present invention has substantially the same configuration and exhibits the same function and effect regardless of the case. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described more specifically with reference to examples.

(Example)
A composition for forming a shielding layer having the following composition is uniformly coated on a triacetyl cellulose film with a bar coater, dried at 90 ° C. for 3 minutes, and then irradiated with 100 mJ / cm ² of ultraviolet light in a nitrogen atmosphere to form a shielding layer Formed.
When the adhesion evaluation with the triacetyl cellulose film was performed on the shielding layer by a cross-cut tape peeling test described later, the result was 50/100.
A composition for forming a photo-alignment layer having the following composition was coated on the shielding layer with a spin coater and dried at 100 ° C. for 3 minutes to form a smooth coating film of about 100 nm. This coating film was irradiated with polarized ultraviolet rays at 10 mJ / cm ² in an air atmosphere to form a photo-alignment layer.
Further, on the photo-alignment layer, a composition for forming an optically anisotropic layer having the following composition was coated with a spin coater, dried, heated and oriented, and then cured by irradiation with ultraviolet rays of 120 mJ / cm ^{2 in} a nitrogen atmosphere. An isotropic layer was formed.
As a result, a uniform and non-uniform retardation plate could be obtained.

<Composition (Example) of composition for shielding layer formation>
-Isocyanuric acid EO-modified diacrylate monomer (trade name Aronix M-215: manufactured by Toagosei Co., Ltd.) 50 parts by weight-UV reactive monomer (trade name: PET-30: manufactured by Nippon Kayaku Co., Ltd.) 50 parts by weight-Photopolymerization initiator (Product name Irgacure 184
: Ciba Specialty Chemicals) 5 parts by weight ・ 75 parts by weight of butyl acetate ・ 75 parts by weight of methyl ethyl ketone

<Composition of composition for forming photo-alignment layer (Example)>
・ Photodimerization type material having cinnamoyl group 1 part by weight ・ Cyclohexanone 99 parts by weight

<Composition of composition for forming optically anisotropic layer (Example)>
-UV curable liquid crystal reactive monomer (nematic liquid crystal) 20 parts by weight-Photopolymerization initiator
(Product name Irgacure 907:
: Ciba Specialty Chemicals Co., Ltd.) 0.6 parts by weight ・ Methyl isobutyl ketone (MIBK) 80 parts by weight

(Comparative Example 1)
A shielding layer was prepared in the same manner as in Example 1 except that the composition for forming a shielding layer having the following composition was used. When the adhesion evaluation with the triacetyl cellulose film was performed on the shielding layer by a cross-cut tape peeling test described later, the result was 50/100.
Moreover, as a result of producing a retardation plate by the same method as in Example 1, unevenness occurred and a good retardation plate could not be obtained.

<Composition for shielding layer formation (Comparative Example 1)>
UV-reactive monomer (trade name PET-30: Nippon Kayaku Co., Ltd.) 100 parts by weight Photopolymerization initiator (trade name Irgacure 184
: Ciba Specialty Chemicals) 5 parts by weight ・ 75 parts by weight of butyl acetate ・ 75 parts by weight of methyl ethyl ketone

(Comparative Example 2)
A shielding layer was prepared in the same manner as in Example 1 except that the composition for forming a shielding layer having the following composition was used. When the adhesion evaluation with the triacetyl cellulose film was performed on the shielding layer by a cross-cut tape peeling test described later, a result of 0/100 was obtained.
Moreover, as a result of producing a retardation plate by the same method as in Example 1, unevenness occurred and a good retardation plate could not be obtained.

<Composition for shielding layer formation (Comparative Example 2)>
・ Ultraviolet-reactive monomer (trade name: Aronix SR-349: manufactured by Toa Gosei Co., Ltd.) 100 parts by weight ・ Photopolymerization initiator (trade name: Irgacure 184
: Ciba Specialty Chemicals) 5 parts by weight ・ 75 parts by weight of butyl acetate ・ 75 parts by weight of methyl ethyl ketone

(Cross-cut tape peeling test)
The cross-cut tape peeling test was carried out using cellophane tape (trade name CT-24: manufactured by Nichiban Co., Ltd.) in accordance with JIS K5600-5-6, and was then adhered to the film with the belly of the finger and then peeled off. Evaluation was performed by counting the squares in which no peeling occurred among 100 squares, and the case where the shielding layer was not peeled was 100/100, and the case where the shielding layer was completely peeled was 0/100.

(Unevenness evaluation method)
The unevenness evaluation method was performed by visually observing unevenness when the retardation plate was sandwiched between two polarizing plates and observed with transmitted light. The judgment was “X” when the unevenness was visually confirmed, and “◯” when it was not confirmed.

  The results of the above Examples, Comparative Example 1 and Comparative Example 2 are shown in the following table.

It is a schematic sectional drawing which shows an example of the polymer laminated body of this invention. It is a schematic sectional drawing which shows an example of the phase difference plate of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent base material 2 ... Shielding layer 3 ... Photo-alignment layer 4 ... Optical anisotropic layer 11 ... Polymer laminated body 12 ... Phase difference plate

Claims (6)

A polymer laminate having a transparent substrate, a shielding layer formed on the transparent substrate and made of a transparent resin, and a photo-alignment layer formed on the shielding layer and exhibiting the ability to align liquid crystal molecules by light irradiation. Because
A polymer laminate comprising a polymer compound having an isocyanuric acid skeleton in the shielding layer.   The polymer laminate according to claim 1, wherein the polymer compound having an isocyanuric acid skeleton includes a polymer of monomers of isocyanuric acid acrylates.   3. The polymer laminate according to claim 1, wherein the polymer compound having an isocyanuric acid skeleton is a polymer of a monomer of isocyanuric acid acrylates and a polyfunctional (meth) acrylate monomer. body.   4. The polymer laminate according to any one of claims 1 to 3, wherein the constituent material of the photo-alignment layer is made of a photoreactive material that causes a photodimerization reaction.   The polymer laminate according to any one of claims 1 to 4, wherein the transparent substrate is a triacetyl cellulose film.   A retardation film comprising an optically anisotropic layer on the photo-alignment layer of the polymer laminate according to any one of claims 1 to 5.

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