JP5028055B2 - Composition for optical alignment film and optical anisotropic body - Google Patents

Description

  The present invention relates to a composition for a photoalignment film that is useful as a liquid crystal alignment film for a liquid crystal display element or an optical anisotropic body, and further relates to an optical anisotropic body using a photoalignment film made of the composition for a photoalignment film.

  The liquid crystal alignment film is used not only for the purpose of alignment of liquid crystal molecules in a liquid crystal display device but also as a material for an optical compensation sheet (retardation plate) which is a kind of optical anisotropic body between a liquid crystal cell and a polarizing plate. The Specifically, a liquid crystal alignment film is used as a material for aligning the polymerizable liquid crystal material, which is an optical anisotropic body obtained by curing the polymerizable liquid crystal material in an aligned state.

Conventionally, as the liquid crystal alignment film, a rubbing film obtained by rubbing a polymer film such as polyimide in one direction with a cloth or the like is used. However, in the rubbing method, fine scratches on the surface of the polymer film due to mechanical rubbing may cause liquid crystal alignment defects, and uneven alignment may occur due to non-uniform pressing pressure during rubbing. There is a problem that the definition of the liquid crystal element is lowered.
In addition, the optical compensation sheet (retardation plate) is often used for the purpose of widening the wavelength band and improving the accuracy of the viewing angle. In that case, for example, a quarter wavelength plate and a half wavelength plate are used. Or a laminate of an A-plate and a C-plate. However, when the method for producing the laminate, that is, the step of curing the polymerizable liquid crystal layer after the formation of the liquid crystal alignment film layer is repeated, the apparatus becomes very large when the polymerizable liquid crystal layer is formed by rubbing. It cannot be created continuously. Therefore, there is a need for a method for obtaining a liquid crystal alignment film that can continuously perform all the lamination steps of the liquid crystal alignment film and the liquid crystal layer.

In order to solve such a problem, a liquid crystal alignment film manufacturing technique that does not perform rubbing has recently attracted attention. In particular, the photo-alignment method, which obtains liquid crystal alignment by irradiating light with some anisotropy on the film provided on the substrate, is expected to be put to practical use because of its excellent mass productivity and compatibility with large substrates. Yes.
Examples of such photo-alignment films include anisotropic photolysis such as azobenzene derivatives such as azobenzene derivatives, compounds that undergo photodimerization reactions such as cinnamate, coumarin, and chalcone, and polyimides that have sites that generate photodimerization reactions. There are compounds that result.

For example, compounds represented by the following structural formulas are known as photo-alignment film materials that are re-aligned with the light having the lowest irradiation anisotropy (hereinafter referred to as sensitivity) and have excellent liquid crystal alignment ability. (See Patent Document 1 and Non-Patent Document 1). The compound having an azo structure exhibits a liquid crystal alignment ability at a low irradiation dose of, for example, 500 mJ / cm ² .
However, the optical anisotropic layer cured using the photo-alignment film using the compound and aligned in the polymerizable liquid crystal material deteriorates the optical anisotropic layer due to the high temperature brought about in the subsequent process, and the optical characteristics are There was a problem of deterioration.

SID01 DIGEST 1170 (2001) Japanese Patent Laid-Open No. 5-232473 JP 2002-250924 A JP 2005-173547 A JP 2005-173548 A

  The problem to be solved by the invention is to provide a composition for a photo-alignment film that provides an optically anisotropic body that has high sensitivity and does not deteriorate due to high temperature.

  The present inventors have found that a composition for a photoalignment film in which a specific compound is added to a highly sensitive compound represented by the above structural formula can solve the above problems.

  That is, the present invention has a compound represented by the general formula (1), a compound represented by the general formula (2-1), a compound represented by the general formula (2-2), and a hydroxyl group as a substituent. Provided is a composition for a photoalignment film comprising at least one compound (2) selected from the group consisting of a triphenylene derivative (2-3).

（１）

(1)

(In the formula, R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a carboxyl group or an alkali metal salt thereof, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, —OR ⁵ (however, R ⁵ represents an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms. , hydroxylalkyl group having 1 to 4 carbon atoms, -CONR ⁶ R ⁷ (provided that ^{R 6} and ^{R 7} are each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms and) or methoxycarbonyl group R ³ and R ⁴ are each independently a carboxyl group or an alkali metal salt thereof, a sulfo group or an alkali metal salt thereof, a nitro group, an amino group, an alkoxycarbonyl group Or represents a hydroxyl group.)

（２−１）

(2-1)

(In General Formula (2-1), R ¹¹ and R ¹² are each independently a hydroxyl group, a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, and Represents a polymerizable functional group selected from the group consisting of maleimide groups, X ¹¹ represents a single bond when R ¹¹ is a hydroxyl group, and — (A ¹ -B ¹ ) when R ¹¹ is a polymerizable functional group. _m ¹² represents a linking group, and X ¹² represents a single bond when R ¹² is a hydroxyl group, and represents — (A ² -B ² ) _n — when R ¹² is a polymerizable functional group. Wherein A ¹ is bonded to R ¹¹ and A ² is bonded to R ^12. A ¹ and A ² are each independently a single bond or divalent carbonization. It represents a hydrogen group, ^{B 1} and ^{B 2} each independently represent a single bond, -O -, - CO- -, -O-CO-, -CO-NH-, -NH-CO-, -NH-CO-O- or -O-CO-NH-, wherein m and n are each independently 1 to 4; Represents an integer, provided that when m or n is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different, provided that two B ¹ or B ² A ¹ or A ² sandwiched between them is not a single bond.
R ¹³ and R ¹⁴ are each independently a hydrogen atom, a halogen atom, a carboxyl group or an alkali metal salt thereof, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, —OR ¹⁷ (where R ¹⁷ is An alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms), the number of carbon atoms 1-4 hydroxyalkyl group or a -CONR ¹⁸ R ¹⁹ (R ¹⁸ and R ¹⁹ are each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms and) represents or methoxycarbonyl group.
R ¹⁵ and R ¹⁶ each independently represents a carbamoyl group or a sulfamoyl group. )

（２−２）

(2-2)

(In General Formula (2-2), R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and A ¹¹ and A ¹² each independently represents a naphthalene ring having an amino group and a sulfo group or an alkali metal salt thereof as a substituent, or a benzene ring having an amino group and a sulfo group or an alkali metal salt thereof as a substituent.

Further, the present invention provides an optical anisotropic body obtained by polymerizing a polymerizable liquid crystal composition film prepared on a liquid crystal alignment film in an aligned state, wherein the liquid crystal alignment film is the photo-alignment described above. Provided is an optical anisotropic body obtained by orienting a film of a film composition.

  By using the composition for photo-alignment film of the present invention, it is highly sensitive and used for an adhesive member used in a cell manufacturing process, or an adhesive member, a polymerizable liquid crystal composition solution, an alignment film solution, etc. A photo-alignment film that is not affected by an organic solvent and an optical anisotropic body that is not affected by an organic solvent or the like using the photo-alignment film.

（１）

(1)

(Compound represented by the general formula (1))
In the general formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a carboxyl group, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, —OR ⁵ (where R ⁵ Represents a lower alkyl group having 1 to 6 carbon atoms, a lower alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a lower alkoxy group having 1 to 6 carbon atoms. ), A hydroxyalkyl group having 1 to 4 carbon atoms, or -CONR ⁶ R ⁷ (R ⁶ and R ⁷ each independently represents a hydrogen atom or a lower alkyl group having 1 to 6 carbon atoms) or a methoxycarbonyl group Represents. However, the carboxyl group may form a salt with the alkali metal.
Examples of the halogen atom include a fluorine atom and a chlorine atom. Examples of the halogenated methyl group include a trichloromethyl group and a trifluoromethyl group. Examples of the halogenated methoxy group include a chloromethoxy group and a trifluoromethoxy group.
Examples of the lower alkyl group having 1 to 6 carbon atoms of R ⁵ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a 1-methylethyl group. Examples of the lower alkyl group having 1 to 6 carbon atoms substituted by the lower alkoxy group having 1 to 6 carbon atoms represented by R ⁵ include a methoxymethyl group, a 1-ethoxyethyl group, and a tetrahydropyranyl group. It is done.
Examples of the hydroxyalkyl group having 1 to 4 carbon atoms include hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxy A butyl group etc. are mentioned.
Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁶ and R ⁷ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a 1-methylethyl group.
Among these, a halogen atom, carboxyl group, halogenated methyl group, halogenated methoxy group, methoxy group, ethoxy group, propoxy group, hydroxymethyl group, carbamoyl group, dimethylcarbamoyl group, and cyano group are preferable, carboxyl group, hydroxymethyl A group or a trifluoromethyl group is particularly preferred in that good orientation can be obtained.

Also, R ¹ and R ² are excellent in photo-alignment properties when the phenylene groups at both ends of the 4,4′-bis (phenylazo) biphenyl skeleton are substituted in the meta position as viewed from the azo group, preferable.

R ³ and R ⁴ each independently represent a carboxyl group, a sulfo group, a nitro group, an amino group, an alkoxycarbonyl group, or a hydroxy group. However, the carboxyl group and the sulfo group may form a salt with an alkali metal such as lithium, sodium or potassium.
When R ³ and R ⁴ are substituted at the 2,2′-positions of the 4,4′-bis (phenylazo) biphenyl skeleton, excellent photoalignment can be obtained, which is particularly preferable.

R ³ and R ⁴ in the general formula (1) are presumed to be sites that most affect the photo-alignment performance and other characteristics, and may vary depending on the types and combinations of substituents that can be introduced into R ³ and R ^4. Characteristics can be obtained.
When R ³ and R ⁴ are a carboxyl group or a salt thereof, a sulfo group or a salt thereof, it has a high affinity for a transparent electrode such as glass or ITO, and a photo-alignment film can be uniformly formed on the substrate surface. This is preferable because it is possible.
The compound represented by the general formula (1) may be a single compound or a mixture of compounds having different R ^{1 to} R ⁴ within the range of the compound represented by the general formula (1).

The compound represented by the general formula (1), the compound represented by the general formula (2-1), the compound represented by the general formula (2-2), and a triphenylene derivative having a hydroxyl group as a substituent (2- By using in combination with at least one compound (2) selected from the group consisting of 3), a photo-alignment film having excellent heat resistance can be obtained while maintaining sensitivity.
As the compound represented by the general formula (1), when R ³ and R ⁴ in the general formula (1) are a sulfo group or an alkali metal salt thereof, it is uniform on the substrate surface and has high sensitivity. Moreover, it is still preferable that a photo-alignment film having excellent heat resistance can be obtained. Further, R ¹ and R ² in the general formula (1) are preferably a carboxyl group or an alkali metal salt thereof, a hydroxymethyl group or a trifluoromethyl group, more preferably a carboxyl group or an alkali metal salt or hydroxymethyl group thereof. A carboxyl group or an alkali metal salt thereof is particularly preferable.

(Compound (2) Compound represented by Formula (2-1))

（２−１）

(2-1)

In general formula (2-1), R ¹¹ and R ¹² are each independently hydroxy, (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group and maleimide group. Represents a polymerizable functional group selected from the group consisting of
X ¹¹ represents a single bond when R ¹¹ is a hydroxy group, and represents a linking group represented by — (A ¹ -B ¹ ) _m — when R ¹¹ is a polymerizable functional group;
X ¹² represents a single bond when R ¹² is a hydroxy group, and represents a linking group represented by — (A ² —B ² ) _n — when R ¹² is a polymerizable functional group. Here, A ¹ is bonded to R ¹¹ , and A ² is bonded to R ¹² . A ¹ and A ² each independently represent a single bond or a divalent hydrocarbon group, and B ¹ and B ² each independently represent a single bond, —O—, —CO—O—, —O—CO—. , -CO-NH-, -NH-CO-, -NH-CO-O- or -O-CO-NH-. m and n each independently represents an integer of 0 to 4. However, when m or n is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different. However, A ¹ or A ² sandwiched between two B ¹ or B ² is not a single bond.
R ¹³ and R ¹⁴ are each independently a hydrogen atom, a halogen atom, a carboxyl group, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, or —OR ¹⁷ (wherein R ¹⁷ is a group having 1 to 6 represents a lower alkyl group having 6 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a lower alkyl group having 1 to 6 carbon atoms substituted with a lower alkoxy group having 1 to 6 carbon atoms). 4 hydroxyalkyl group or —CONR ¹⁸ R ¹⁹ (R ¹⁸ and R ¹⁹ each independently represents a hydrogen atom or a lower alkyl group having 1 to 6 carbon atoms) or a methoxycarbonyl group. However, the carboxyl group may form a salt with the alkali metal.
R ¹⁵ and R ¹⁶ each independently represents a carbamoyl group or a sulfamoyl group.
Among the compounds of the general formula (2-1), compounds in which R ¹¹ and R ¹² are hydroxy groups and R ¹³ and R ¹⁴ are hydroxyalkyl groups having 1 to 4 carbon atoms are preferred, and R ¹¹ and R ¹² Particularly preferred are compounds wherein is a hydroxy group and R ¹³ and R ¹⁴ are hydroxymethyl groups.

(Compound (2) Compound represented by Formula (2-2))

（２−２）

(2-2)

In General Formula (2-2), R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and A ¹¹ and A ¹² Each independently represents a naphthalene ring having an amino group and a sulfo group as substituents, or a benzene ring having an amino group and a sulfo group as substituents. However, the sulfo group may form a salt with an alkali metal.
As the compound represented by the general formula (2-2), those in which R ²¹ and R ²² are each independently a hydrogen atom, a methyl group, or a methoxy group are preferable.

(Compound (2) Triphenylene derivative (2-3) having a hydroxyl group as a substituent)
In the triphenylene derivative (2-3) having a hydroxyl group as a substituent, the number of hydroxyl groups as a substituent is not particularly limited, but is preferably 3 to 6, and most preferably 6.

  At least one selected from the group consisting of the compound represented by the general formula (2-1), the compound represented by the general formula (2-2), and the triphenylene derivative (2-3) having a hydroxyl group as a substituent. The two compounds (2) are preferably added so that the ratio of the compound represented by the general formula (1) to the compound (2) is in the range of 1: 0.2 to 1: 5. More preferably, the range is from 1: 0.5 to 1: 2. In addition, the compound represented by the general formula (2) may be used alone or as a mixture of a plurality of different compounds within the range of the compound represented by the general formula (2).

Examples of the compound represented by the general formula (1) include compounds having the following structure.

Examples of the compound (2-1) include compounds having the following structure.

Examples of the compound (2-2) include compounds having the following structure.

Examples of the triphenylene derivative (2-3) having a hydroxyl group as the compound substituent include compounds having the following structure.

  The compound represented by the general formula (1) exhibits high solubility in water or a polar organic solvent, and exhibits good affinity for glass and the like. A composition for a photo-alignment film formed by dissolving the compound in water or a polar organic solvent is applied to a substrate such as glass, and then the water or the polar organic solvent is removed. A film for a photoalignment film can be formed.

  The photo-alignment film using the composition for photo-alignment film of the present invention can be suitably used as a liquid crystal alignment film of a polymerizable liquid crystal composition used for producing an optical anisotropic body.

(solvent)
The composition for photo-alignment films used in the present invention usually uses a solvent for the purpose of improving the coatability. Although there is no limitation in particular as a solvent used for a solvent, The solvent in which the said compound shows favorable solubility is used. For example, alcohol solvents such as methanol and ethanol, diol solvents such as ethylene glycol, propylene glycol and 1,3-butanediol, tetrahydrofuran, 2-methoxyethanol, 2-butoxyethanol, 2- (2-ethoxyethoxy) Examples include ether solvents such as ethanol and 2- (2-butoxyethoxy) ethanol, amide solvents such as 2-pyrrolidone, N-methylpyrrolidone, dimethylformamide, and dimethylacetamide, γ-butyrolactone, chlorobenzene, and dimethyl sulfoxide. . These can be used alone or in combination of two or more. Moreover, you may add a well-known and usual additive in the range which does not impair the effect of this invention.
Usually, it prepares so that solid content ratio may be 0.2 mass% or more. It is preferable to prepare so that it may become 0.5-10 mass% especially.

(Additive)
In order to uniformly apply the composition for photo-alignment film used in the present invention and obtain a photo-alignment film having a uniform film thickness, a general-purpose additive can be used. For example, additives such as a leveling agent, a thixotropic agent, a surfactant, an ultraviolet absorber, an infrared absorber, an antioxidant, a surface treatment agent, and the like can be added to the extent that the liquid crystal alignment ability is not significantly reduced.

(Photo-alignment film, optical anisotropic body having photo-alignment film or method for producing optical element)
In order to obtain a photo-alignment film by using the composition for photo-alignment film of the present invention, the composition for photo-alignment film has anisotropy such as ultraviolet light or visible light after coating and drying on the substrate. Light is irradiated to orient the compound represented by the general formula (1).

(Coating, substrate)
The composition for photo-alignment film used in the present invention is applied on a substrate by a known and commonly used method such as spin coating method, gravure printing method, flexographic printing method, ink jet method, die coating method, cap coating method, dipping method, etc. A film for photo-alignment film is obtained by printing and drying. The substrate to be used is a substrate usually used for liquid crystal display elements and optical anisotropic bodies, and has a solvent resistance that can withstand heating during the drying after the application of the composition solution for photo-alignment film or during the production of the liquid crystal element. If it is a material which has heat resistance, there will be no restriction | limiting in particular. Examples of such a substrate include a glass substrate, a ceramic substrate, a metal substrate, a polymer material substrate, and the like. As the polymer material substrate, cellulose derivatives, polycycloolefin derivatives, polyesters, polyolefins, polycarbonates, polyacrylates, polyarylates, nylons, polystyrenes, and the like can be used. In order to improve the applicability and adhesion of the composition for photo-alignment films, surface treatment of these substrates may be performed. Examples of the surface treatment include ozone treatment and plasma treatment. In order to adjust light transmittance and reflectance, an organic thin film, an inorganic oxide thin film, a metal thin film, or the like may be provided on the substrate surface by a method such as vapor deposition.
Usually, since the solution diluted with the organic solvent is applied, it is dried after application to obtain a film for a photoalignment film.

(Photoisomerization process)
A film for photoalignment film obtained by the above method is irradiated with anisotropic light to give a liquid crystal alignment function (hereinafter abbreviated as photoisomerization step), and photoisomerized film for photoalignment film is obtained. create. The anisotropic light used in the photoisomerization step includes polarized light such as linearly polarized light and elliptically polarized light, or non-polarized light from a direction oblique to the substrate surface. The polarized light may be either linearly polarized light or elliptically polarized light, but it is preferable to use linearly polarized light having a high extinction ratio in order to perform photoalignment efficiently.

Moreover, since it is necessary to use a polarizing filter or the like in order to obtain polarized light in the light irradiation device, there is a disadvantage that the light intensity irradiated to the film surface is reduced. The irradiation method does not require a polarizing filter or the like in the irradiation device, and has an advantage that a large irradiation intensity can be obtained and the irradiation time for photo-alignment can be shortened. In this case, the incident angle of non-polarized light is preferably in the range of 10 ° to 80 ° with respect to the substrate normal, and in consideration of the uniformity of the irradiation energy on the irradiated surface, the pretilt angle obtained, the alignment efficiency, etc., 20 ° to 60 °. A range of ° is more preferred and 45 ° is most preferred.
The light to be irradiated may be light in a wavelength region in which the photo-alignment group of the compound to be used has absorption. For example, when the photo-alignment group has an azobenzene structure, ultraviolet rays having a wavelength of 330 to 500 nm that have strong absorption due to the π → π ^* transition of azobenzene are particularly preferable.

Examples of the light source of the irradiation light include an ultraviolet light source such as a xenon lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, and a metal halide lamp, an ultraviolet light laser such as KrF and ArF, and a visible light laser such as an Ar ion laser. In particular, when the photo-alignment group has an azobenzene structure, it is possible to effectively use an ultra-high pressure mercury lamp having a particularly large emission intensity of ultraviolet light at 365 nm.
Ultraviolet linearly polarized light can be obtained by passing the light from the light source through a polarizing prism such as a polarizing filter, Glan-Thompson, and Glan-Teller.
Moreover, it is particularly preferable that the irradiated light is substantially parallel light regardless of whether polarized light or non-polarized light is used.

  Further, when irradiating polarized light, if a photomask is used, liquid crystal alignment ability can be generated in two or more different directions in a pattern on the photo-alignment film. Specifically, after the composition for photo-alignment film of the present invention is applied and dried, the substrate is covered with a photomask, and the entire surface is irradiated with polarized light or non-polarized light to give liquid crystal alignment ability to the exposed portion in a pattern. By repeating this a plurality of times as necessary, liquid crystal alignment ability can be generated in a plurality of directions.

Further, in some cases, the photo-alignment film can be cooled after the photoisomerization step. As a cooling method, the photo-isomerized film for the photo-alignment film may be cooled. For example, the entire substrate is cooled by a known and common cooling device such as a cold plate, a chamber, a low-temperature thermostat, or the like.
The cooling condition is that the cooling temperature is 20 ° C. for 1 minute or longer, but this is not the case when the cooling temperature is lower than 20 ° C. Although it should just be more than melting | fusing point of the solvent to be used as a cooling temperature, the range of -40 degreeC-20 degreeC is preferable normally. In order to obtain a more stable photo-alignment film with improved liquid crystal alignment function, the temperature is preferably 10 ° C. or less, and the cooling time is preferably 5 minutes or more. In order to further shorten the cooling time, the cooling temperature is preferably 5 ° C. or lower.
In order to prevent condensation, the cooling may be performed in a dry air, nitrogen, or argon atmosphere, or the substrate may be cooled while blowing dry air, nitrogen, or the like onto the substrate.

(Optical anisotropic)
In order to obtain an optical anisotropic body using the composition for photo-alignment film of the present invention, a polymerizable liquid crystal is applied on the photo-alignment film described above and polymerized in an aligned state.
In the case of photopolymerization, the polymerization operation of the polymerizable liquid crystal composition may be performed in the same manner as the polymerization operation in the case of forming the photo-alignment film. Polymerization by heating is preferably performed at a temperature at which the polymerizable liquid crystal composition exhibits a liquid crystal phase or at a temperature lower than that. In particular, when a thermal polymerization initiator that releases radicals by heating is used, the cleavage temperature is the above temperature. It is preferable to use those within the region. When the thermal polymerization initiator and the photopolymerization initiator are used in combination, the polymerization temperature and the polymerization temperature are set so that the polymerization speeds of both the photo-alignment film and the polymerizable liquid crystal film are not greatly different together with the limitation of the temperature range. It is preferred to select each initiator. Although the heating temperature depends on the transition temperature from the liquid crystal phase to the isotropic phase of the polymerizable liquid crystal composition, it is preferably performed at a temperature lower than the temperature at which inhomogeneous polymerization is induced by heat. 300 degreeC is preferable, 30 to 200 degreeC is more preferable, and 30 to 120 degreeC is especially preferable. For example, when a polymeric group is a (meth) acryloyl group, it is preferable to carry out at a temperature lower than 90 degreeC.

The photoinitiator used by this invention can use a well-known and usual thing.
Photopolymerization initiators that can be used with ultraviolet light of 320 nm or less include 1-hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by Ciba Specialty Chemicals), 1- [4- (2-hydroxyethoxy) -phenyl] -2 -Hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one ("Darocur 1173" manufactured by Merck & Co., Inc.) and the like.
Examples of the photopolymerization initiator having a light absorption wavelength band different from the light absorption band of the azobenzene skeleton include those obtained by combining a near infrared absorbing dye and organic boron described in Japanese Patent No. 3016606. .
Examples of other photopolymerization initiators include 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one ("Darocur 1116" manufactured by Merck & Co., Inc.), 2-methyl-1-[( Methylthio) phenyl] -2-morpholinopropane-1 (“Irgacure 907” manufactured by Ciba Specialty Chemicals). Benzylmethylketal ("Irgacure 651" manufactured by Ciba Specialty Chemicals). A mixture of 2,4-diethylthioxanthone (“Kayacure DETX” manufactured by Nippon Kayaku Co., Ltd.) and ethyl p-dimethylaminobenzoate (“Kayacure EPA” manufactured by Nippon Kayaku Co., Ltd.) -ITX ") and a mixture of ethyl p-dimethylaminobenzoate, acylphosphine oxide (" Lucirin TPO "manufactured by BASF), and the like. The amount of the photopolymerization initiator used is preferably 10% by mass or less, particularly preferably 0.5 to 5% by mass with respect to the polymerizable liquid crystal compound.

  In addition, as the thermal polymerization initiator used in the thermal polymerization, known ones can be used, for example, methyl acetoacetate peroxide, cumene hydroperoxide, benzoyl peroxide, bis (4-t-butyl). (Cyclohexyl) peroxydicarbonate, t-butyl peroxybenzoate, methyl ethyl ketone peroxide, 1,1-bis (t-hexyl peroxy) 3,3,5-trimethylcyclohexane, p-pentahydroperoxide, Organic peroxides such as t-butyl hydroperoxide, dicumyl peroxide, isobutyl peroxide, di (3-methyl-3-methoxybutyl) peroxydicarbonate, 1,1-bis (t-butylperoxy) cyclohexane Oxide, 2,2'-azobisisobutyronitrile Azonitrile compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile), azoamidin compounds such as 2,2′-azobis (2-methyl-N-phenylpropion-amidin) dihydrochloride, 2,2 ′ Azoamide compounds such as azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, alkyl such as 2,2′azobis (2,4,4-trimethylpentane) Compounds and the like can be used. The amount of the thermal polymerization initiator used is preferably 10% by mass or less, particularly preferably 0.5 to 5% by mass with respect to the polymerizable liquid crystal compound.

(Polymerizable liquid crystal composition)
The polymerizable liquid crystal composition used in the present invention is a liquid crystal composition containing a compound having a polymerizable group that exhibits liquid crystallinity alone or in a composition with another liquid crystal compound. For example, Handbook of Liquid Crystals (D. Demus, J. W. Goodbye, GW Gray, H. W. Spiss, V. Vill, edited by Wiley-VCH, 1998), Quarterly Chemical Review. 22, Liquid Crystal Chemistry (Edited by Chemical Society of Japan, 1994), or JP-A-7-294735, JP-A-8-3111, JP-A-8-29618, JP-A-11-80090, 1,4-phenylene group, 1,4-cyclohexene, as described in Kaihei 11-148079, JP-A 2000-178233, JP-A 2002-308831, and JP-A 2002-145830. A rod-like polymerizable liquid crystal compound having a rigid site called a mesogen in which a plurality of structures such as a sylene group are connected, and a polymerizable functional group such as a (meth) acryloyl group, a vinyloxy group, and an epoxy group, or JP 2004-2373 A A rod-like polymerizable liquid crystal compound having a maleimide group as described in JP-A-2004-99446, Or a rod-like polypolar liquid crystal compound having an allyl ether group as described in JP-A No. 2004-149522, or, for example, Handbook of Liquid Crystals (D. Demus, J. W. Goodby, GW). Gray, H. W. Spiess, V. Vill, published by Wiley-VCH, 1998), Quarterly Chemical Review No. 22. Liquid crystal chemistry (edited by Chemical Society of Japan, 1994) and discotic polymerizable compounds described in JP-A-07-146409. Among these, a rod-like liquid crystal compound having a polymerizable group is preferable because it can easily produce a liquid crystal having a temperature range around room temperature.

(solvent)
Although there is no limitation in particular as a solvent used for the said polymeric liquid crystal composition, the solvent in which the said compound shows favorable solubility can be used. For example, aromatic hydrocarbons such as toluene, xylene and mesitylene, ester solvents such as methyl acetate, ethyl acetate and propyl acetate, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, tetrahydrofuran, 1,2-dimethoxyethane And ether solvents such as anisole, amide solvents such as N, N-dimethylformamide and N-methyl-2-pyrrolidone, γ-butyrolactone, and chlorobenzene. These can be used alone or in combination of two or more. Moreover, an additive can also be added.

  In the polymerizable liquid crystal composition of the present invention, a liquid crystal compound having no polymerizable group may be added as necessary. However, if the addition amount is too large, the liquid crystal compound may be eluted from the obtained optical anisotropic body to contaminate the laminated member, and in addition, the heat resistance of the optical anisotropic body may be reduced. In this case, the content is preferably 30% by mass or less, more preferably 15% by mass or less, and particularly preferably 5% by mass or less with respect to the total amount of the polymerizable liquid crystal compound.

  The polymerizable liquid crystal composition used in the present invention may be added with a compound having a polymerizable group but not a polymerizable liquid crystal compound. Such a compound can be used without particular limitation as long as it is generally recognized as a polymerizable monomer or polymerizable oligomer in this technical field. When adding, it is preferable that it is 5 mass% or less with respect to the polymeric liquid crystal composition of this invention, and 3 mass% or less is still more preferable.

The polymerizable liquid crystal composition used in the present invention may be added with a compound having optical activity, that is, a chiral compound. The chiral compound itself does not need to exhibit a liquid crystal phase, and may or may not have a polymerizable group. Moreover, the direction of the spiral of the chiral compound can be appropriately selected depending on the intended use of the polymer.
Specifically, for example, CB-15, “C-15”, Merck manufactured by BDH Corporation having cholesterol as a chiral group having cholesteryl group as cholesterol group, cholesterol stearate, and 2-methylbutyl group as a chiral group. “S-1082” manufactured by the company, “CM-19”, “CM-20”, “CM” manufactured by Chisso, “S-811” manufactured by Merck having 1-methylheptyl group as a chiral group, “CM-21”, “CM-22” and the like manufactured by the company can be mentioned.
When adding a chiral compound, depending on the use of the polymer of the polymerizable liquid crystal composition of the present invention, the value obtained by dividing the thickness (d) of the obtained polymer by the helical pitch (P) in the polymer (d / P) is preferably added in an amount in the range of 0.1 to 100, more preferably in the range of 0.1 to 20.

  A stabilizer can be added to the polymerizable liquid crystal composition used in the present invention in order to improve storage stability. Examples of the stabilizer include hydroquinone, hydroquinone monoalkyl ethers, tert-butylcatechols, pyrogallols, thiophenols, nitro compounds, β-naphthylamines, β-naphthols and the like. When adding, it is preferable that it is 1 mass% or less with respect to the polymeric liquid crystal composition of this invention, and 0.5 mass% or less is especially preferable.

  When the optical anisotropic body of the present invention is used for, for example, a polarizing film or alignment film raw material, printing ink, paint, or protective film, the polymerizable liquid crystal composition used in the present invention has its Depending on the purpose, metals, metal complexes, dyes, pigments, fluorescent materials, phosphorescent materials, surfactants, leveling agents, thixotropic agents, gelling agents, polysaccharides, ultraviolet absorbers, infrared absorbers, antioxidants, ions An exchange resin or a metal oxide such as titanium oxide may be added.

  In order to stabilize the solvent resistance and heat resistance of the obtained optical anisotropic body, the optical anisotropic body can be subjected to a heat aging treatment. In this case, it is preferable to heat above the glass transition point of the prepolymerizable liquid crystal film. Usually, 50 to 300 ° C is preferable, 80 to 240 ° C is more preferable, and 100 to 220 ° C is more preferable.

  The optical anisotropic body of the present invention can be peeled off from the substrate and used alone as an optical anisotropic body, or it can be used as it is without being peeled off from the substrate. In particular, since it is difficult to contaminate other members, it is useful when used as a laminated substrate or by being attached to another substrate. In some cases, optical anisotropic bodies can be laminated over several layers. In that case, the above process may be repeated a plurality of times, and an optically anisotropic laminate can be formed.

  EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples. Unless otherwise specified, “part” and “%” are based on mass.

(Preparation of composition (1) for photo-alignment film)
48 parts of N-methyl-2-pyrrolidone (NMP) is obtained by adding 1 part of the compound represented by the formula (a) as the compound represented by the general formula (1) and 1 part of the compound represented by the formula (b) as the compound (2). Then, 50 parts of 2-butoxyethanol (BC) was added to prepare a solution. The obtained solution was filtered with a 0.45 μm membrane filter to obtain a composition (1) for a photo-alignment film.

（ａ）

(A)

（ｂ）

(B)

(Preparation of compositions for photo-alignment film (2) to (14))
The composition for photoalignment film (2) is the same as the composition for photoalignment film (1) except that the compound represented by formula (1), the type of compound (2), and the blending (part) are changed. To (14). The composition is as shown in Table 1.

  All solvents are one-to-one mixtures of N-methyl-2-pyrrolidone (NMP) and 2-butoxyethanol (BC). The structures of the compounds (c) to (g) are as follows.

（ｃ）

(C)

（ｄ）

(D)

（ｅ）

(E)

（ｆ）

(F)

（ｇ）

(G)

(Preparation of polymerizable liquid crystal composition (LC-1))
After dissolving 15 parts of the compound represented by the formula (h) and 15 parts of the compound represented by the formula (i) in 70 parts of xylene, 1.2 parts of Irgacure 907 (manufactured by Ciba Specialty Chemicals Co., Ltd.), 0.3 parts of the acrylic copolymer represented by k) was added to obtain a solution. The obtained solution was filtered with a 0.45 μm membrane filter to obtain a polymerizable liquid crystal composition (LC-1).

(ｈ)

(h)

(ｉ)

(i)

(ｋ)

(k)

(Evaluation method of orientation)
The orientation of the optical anisotropic body was evaluated in five stages by visual observation and observation with a polarizing microscope.
A: Uniform orientation is obtained visually, and there are no defects even when observed with a polarizing microscope. B: Uniform orientation is obtained visually, but the orientation area is 90 to 100% when observed with a polarizing microscope.
C: Although alignment as much as A and B is not obtained visually, the alignment area in observation with a polarizing microscope is 60 to 90%.
D: Nearly non-oriented by visual observation, but the orientation area by polarizing microscope observation is 40 to 60%.
E: No orientation by visual observation, and orientation area by polarization microscope observation is 40% or less

(Method for evaluating heat resistance)
The heat resistance was evaluated by measuring and comparing the retardation of the optical anisotropic body before and after heating at 230 ° C. for 4 hours (Chuo Seiki DI4RD). The retardation before heating is Re1 (nm), the retardation after heating is Re2 (nm), and the percentage of the ratio of the retardation after heating to the retardation before heating is Re% (%) (Re% = Re2 / Re1 × 100). It was used as an index of heat resistance. The better the heat resistance, the less the change in retardation. Therefore, the larger the Re% value, the better the heat resistance.

(Evaluation as an optical anisotropic body)
Example 1
The composition for photo-alignment film (1) was applied onto a glass substrate with a spin coater and dried at 100 ° C. for 1 minute. The dry film thickness at this time was 20 nm.
Next, a linearly polarized light of visible ultraviolet light (irradiation intensity: 10 mW / cm ² ) near 365 nm wavelength is applied to the glass substrate through a wavelength cut filter, a band pass filter and a polarizing filter through an ultra high pressure mercury lamp. Irradiated from the vertical direction and aligned. The irradiation amount was 500 mJ / cm ² .
A polymerizable liquid crystal composition (LC-1) was applied on the obtained photo-alignment film with a spin coater, dried at 80 ° C. for 1 minute, and then irradiated with 1 J / cm ² of ultraviolet light in a nitrogen atmosphere to obtain LC-1 Was polymerized to obtain an optical anisotropic body. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Moreover, the evaluation result of the heat resistance of the optical anisotropic body was excellent in heat resistance with Re% = 70%.

(Example 2)
An optical anisotropic body was produced in the same manner as in Example 1 except that (2) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Moreover, the evaluation result of the heat resistance at that time was excellent in heat resistance with Re% = 75%.

(Example 3)
An optical anisotropic body was produced in the same manner as in Example 1 except that (3) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . The evaluation result of heat resistance at that time was excellent in heat resistance with Re% = 69%.

Example 4
An optical anisotropic body was produced in the same manner as in Example 1 except that (4) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Further, the evaluation result of heat resistance at that time was excellent in heat resistance with Re% = 78%.

(Example 5)
An optical anisotropic body was produced in the same manner as in Example 1 except that (5) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Further, the evaluation result of heat resistance at that time was excellent in heat resistance with Re% = 68%.

(Example 6)
An optical anisotropic body was prepared in the same manner as in Example 1 except that (6) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Further, the evaluation result of heat resistance at that time was excellent in heat resistance with Re% = 73%.

(Example 7)
An optical anisotropic body was produced in the same manner as in Example 1 except that (7) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . The evaluation result of heat resistance at that time was excellent in heat resistance with Re% = 69%.

(Example 8)
An optical anisotropic body was produced in the same manner as in Example 1 except that (8) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Moreover, the evaluation result of the heat resistance at that time was excellent in heat resistance with Re% = 70%.

Example 9
An optical anisotropic body was prepared in the same manner as in Example 1 except that (9) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Moreover, the evaluation result of the heat resistance at that time was excellent in heat resistance with Re% = 65%.

(Example 10)
An optical anisotropic body was produced in the same manner as in Example 1 except that (10) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Moreover, the evaluation result of the heat resistance at that time was excellent in heat resistance with Re% = 67%.

(Example 11)
An optical anisotropic body was produced in the same manner as in Example 1 except that (11) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Moreover, the evaluation result of the heat resistance at that time was excellent in heat resistance with Re% = 70%.

(Example 12)
An optical anisotropic body was produced in the same manner as in Example 1 except that (12) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Moreover, the evaluation result of the heat resistance at that time was excellent in heat resistance with Re% = 75%.

(Example 13)
An optical anisotropic body was produced in the same manner as in Example 1 except that (13) was used instead of (1) as the composition for the photoalignment film. As a result, the orientation was A, and good orientation could be obtained with a small dose of 500 mJ / cm ² . Moreover, the evaluation result of the heat resistance at that time was excellent in heat resistance with Re% = 70%.

(Comparative Example 1)
An optical anisotropic body was prepared in the same manner as in Example 1 except that the composition for photo-alignment film (14) was used instead of (1) as the composition for photo-alignment film. As a result, it was found that the orientation was A and good orientation was obtained with a dose as small as 500 mJ / cm ^2. However, the evaluation result of the heat resistance of this optical anisotropic body was Re% = 59%, It turned out to be inferior.

Claims (2)

A compound represented by the general formula (1) and at least one compound (2) selected from the compounds represented by the general formula (2-1), The composition for photo-alignment films whose ratio with said compound (2) is the range of 1: 0.1-1: 5.

(1)
Wherein R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a carboxyl group or an alkali metal salt thereof, a halogenated methyl group, a halogenated methoxy group, —OR ⁵ (where R ⁵ is a carbon atom An alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms), 1 to 1 carbon atoms 4 represents a hydroxylalkyl group or a methoxycarbonyl group, and R ³ and R ⁴ each independently represents a carboxyl group or an alkali metal salt thereof, a sulfo group or an alkali metal salt thereof, an alkoxycarbonyl group or a hydroxyl group.)

(2-1)
(In General Formula (2-1), R ¹¹ and R ¹² are each independently a hydroxyl group, a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, and Represents a polymerizable functional group selected from the group consisting of maleimide groups, X ¹¹ represents a single bond when R ¹¹ is a hydroxyl group, and — (A ¹ -B ¹ ) when R ¹¹ is a polymerizable functional group. _m ¹² represents a linking group, and X ¹² represents a single bond when R ¹² is a hydroxyl group, and represents — (A ² -B ² ) _n — when R ¹² is a polymerizable functional group. Wherein A ¹ is bonded to R ¹¹ and A ² is bonded to R ^12. A ¹ and A ² are each independently a single bond or divalent carbonization. It represents a hydrogen group, ^{B 1} and ^{B 2} each independently represent a single bond, -O -, - CO- -, -O-CO-, -CO-NH-, -NH-CO-, -NH-CO-O- or -O-CO-NH-, wherein m and n are each independently 1 to 4; Represents an integer, provided that when m or n is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different, provided that two B ¹ or B ² A ¹ or A ² sandwiched between them is not a single bond.
R ¹³ and R ¹⁴ are each independently a hydrogen atom, a halogen atom, a carboxyl group or an alkali metal salt thereof, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, —OR ¹⁷ (where R ¹⁷ is An alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms), the number of carbon atoms 1-4 hydroxyalkyl group or a -CONR ¹⁸ R ¹⁹ (R ¹⁸ and R ¹⁹ are each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms and) represents or methoxycarbonyl group.
R ¹⁵ and R ¹⁶ each independently represents a carbamoyl group or a sulfamoyl group. ) The composition for photoalignment films according to claim 1, which is an optical anisotropic body obtained by polymerizing a polymerizable liquid crystal composition film prepared on a liquid crystal alignment film in an aligned state. An optical anisotropic body obtained by orienting a film of an object.