TW201725242A - Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal component and method for preparing liquid crystal alignment film and liquid crystal component having an excellent initial voltage holding ratio and excellent light resistance - Google Patents

Abstract

The present invention provides a liquid crystal alignment agent capable of obtaining a liquid crystal component with an excellent initial voltage holding ratio and excellent light resistance. The liquid crystal alignment agent comprises polyorganosiloxane (C) having a photo-alignment group, and in at least one molecule including the polyorganosiloxane(C) and polymers different than the polyorganosiloxane (C) contains a partial structure which exhibits liquid crystallinity.

Description

Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal element, liquid crystal alignment film, and method for producing liquid crystal element

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, and a liquid crystal alignment film and a method of producing a liquid crystal element.

The liquid crystal element has a liquid crystal alignment film for aligning liquid crystal molecules. In recent years, with the expansion of use and use environment, the requirements for display performance of liquid crystal panels have become stricter. Therefore, various liquid crystal alignment films for improving various characteristics of liquid crystal panels are being studied (for example, refer to Patent Document 1 and Patent Document 2). Patent Document 1 discloses that a liquid alignment agent containing a polymer having a photo-alignment ability and a polymer exhibiting liquid crystallinity, and a polymer having photo-alignment ability selected from the group consisting of a photo-alignment agent is used. At least one of the group consisting of polylysine, partially ruthenium polyamine and polyimine. Further, Patent Document 2 discloses that a photosensitive side chain type polymer which exhibits liquid crystallinity is used to form a coating film on a substrate, and then irradiated with polarized ultraviolet rays, followed by heating to form a liquid crystal alignment film. [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5407394 [Patent Document 2] International Publication No. 2013/081066

[Problems to be Solved by the Invention] In the process of using a liquid crystal device in a process of being used in a severe environment, such as continuous driving for a long period of time or use in a place where optical stress is present, the liquid crystal element is important. It is difficult to cause deterioration due to light (for example, a decrease in voltage holding ratio) at the time of use, and it is also possible to withstand use in a harsh environment. In addition, in order to improve the display quality of the liquid crystal element, it is important that the initial voltage holding ratio is high. In view of the recent demand for higher performance of the liquid crystal element, it is necessary to obtain a high initial voltage holding ratio and light resistance. A new technology for excellent liquid crystal components.

The present invention has been made in view of the above-described problems, and an object of the invention is to provide a liquid crystal alignment agent which can obtain an initial voltage retention ratio and light resistance, which is excellent in light resistance. [Technical means for solving the problem]

In order to achieve the above-described problems of the prior art, the inventors of the present invention have found that the above problems can be solved by setting the polymer component of the liquid crystal alignment agent to a specific composition, and completed the present invention. Specifically, the following means are provided.

<1> A liquid crystal alignment agent comprising a polyorganosiloxane (C) having a photo-alignment group, and differing from the polyorganosiloxane (C) and the polyorganosiloxane (C) At least one of the polymers contains a partial structure exhibiting liquid crystallinity in the molecule. <2> A liquid crystal alignment film formed using the liquid crystal alignment agent described in <1>. <3> A liquid crystal element comprising the liquid crystal alignment film according to <2>. <4> A method for producing a liquid crystal alignment film, comprising: applying a liquid crystal alignment agent of <1> on a substrate to form a coating film, and performing light irradiation on a substrate surface coated with the liquid crystal alignment agent A step of imparting a liquid crystal alignment ability to the coating film. <5> A method for producing a liquid crystal element, comprising: a step of forming a liquid crystal alignment film on a surface of each of a pair of substrates by the method of the above <4>; and a method of opposing the respective liquid crystal alignment films a step of arranging the liquid crystal cells by arranging the pair of substrates with a liquid crystal layer containing a polymerizable monomer, and a step of irradiating the liquid crystal cells with light. <6> A method for producing a liquid crystal element, comprising: a step of forming a liquid crystal alignment film on a surface of each of a pair of substrates by a method of the above <4> and using a liquid crystal alignment agent containing a polymerizable monomer; A method of arranging the liquid crystal cells by arranging the pair of substrates via a liquid crystal layer, and a step of irradiating the liquid crystal cells with light, in a manner in which the respective liquid crystal alignment films face each other. [Effects of the Invention]

According to the liquid crystal alignment agent of the present invention, a liquid crystal element having a high initial voltage holding ratio and excellent light resistance can be obtained. Further, since the liquid crystal alignment agent of the present invention can be used to produce a liquid crystal alignment film by a photo-alignment method, it is possible to suppress generation of display defects or a decrease in yield due to generation of dust or static electricity, and the like, in addition to the conventional rubbing method. It is excellent in the viewpoint of uniformly imparting liquid crystal alignment ability to the organic thin film formed on the substrate.

The liquid crystal alignment agent of the present disclosure contains a polyorganosiloxane (C) having a photo-alignment group. Further, at least one of a polymer having a partial structure exhibiting liquid crystallinity is used as the polyorganosiloxane (C) and a polymer different therefrom. The partial structure exhibiting liquid crystallinity may be contained in the polyorganosiloxane (C), or may be contained in a polymer different from the polyorganosiloxane (C), or may be contained in the two polymers. From the viewpoint of the initial voltage holding ratio and light resistance of the liquid crystal element, the partial structure exhibiting liquid crystallinity is preferably contained in a polymer different from the polyorganosiloxane (C). In other words, the liquid crystal alignment agent of the present invention preferably contains a polymer (A) exhibiting liquid crystallinity in a predetermined temperature range and a polyorganosiloxane (C) having a photoalignment group. Hereinafter, the polymer (A) and the polyorganosiloxane (C) will be described in detail, and other components which are arbitrarily formulated in the liquid crystal alignment agent of the present invention as needed will be described.

<Polymer (A)> The polymer (A) is not particularly limited as long as it exhibits liquid crystallinity in a predetermined temperature range, and a rigid portion (mesogen structure) is used as a display. A liquid crystal partially structured polymer. The liquid crystal original structure of the polymer (A) is, for example, a structure represented by the following formula (1). [Chemical 1] (In the formula (1), Ar ¹ and Ar ² are each independently a substituted or unsubstituted phenyl or cyclohexyl group, and X ¹ is a single bond, -CO-, -COO-, -C=C-. , -C≡C-, -N=N- or -CONR ¹ - (R ¹ is a hydrogen atom or a monovalent organic group). n is an integer of 1 to 3. When n is 2 or 3, Ar ² , X ¹ independently has the definition. "*" means a bond)

In the formula (1), X ¹ is preferably a single bond or -COO-. Examples of the monovalent organic group of R ¹ include an alkyl group having 1 to 6 carbon atoms, a protective group, and the like. Specific examples of the protective group include a third butoxycarbonyl group, a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethoxycarbonyl group, and an allyloxycarbonyl group. The substituent of the ring portion of Ar ¹ and Ar ² is preferably an alkyl group having 1 to 5 carbon atoms or a halogen atom, and more preferably a methyl group or a fluorine atom. Preferred specific examples of the partial structure represented by the above formula (1) include, for example, 4-biphenylyl group, 4-dicyclohexyl group, p-terphenylene group, 4,4'-exobiphenyl group, and 4 , 4'-bisbicyclohexyl, p-triphenyl, and a group represented by the following formula (1-1) to formula (1-4), respectively, and a methyl group or a fluorine atom at the ring portion of these groups Base and so on. [Chemical 2] (where "*" means the binding key)

The polymer (A) may have a liquid crystal original structure in any of the main chain and the side chain of the polymer, but it is preferable to have a liquid crystal original structure in the side chain from the viewpoint of high effect of improving the light resistance of the liquid crystal element. A side chain type liquid crystalline polymer. Here, in the present specification, the "main chain" of the polymer means a "dry" portion of the chain including the longest atom among the polymers. The "dry" portion is allowed to contain a ring structure. Therefore, the phrase "having a liquid crystal original structure in the main chain of the polymer" means that the structure constitutes a part of the main chain. The "side chain" of the polymer means a portion branched from the "dry" of the polymer. Further, the polymer (A) may have a liquid crystal original structure only in the main chain of the polymer, or may have a liquid crystal original structure only in the side chain, or may have a liquid crystal original structure in both the main chain and the side chain.

The type of the main skeleton of the polymer (A) is not particularly limited, but is preferably a polymer selected from a monomer having a polymerizable unsaturated bond from the viewpoint of affinity with a liquid crystal or mechanical strength (hereinafter also At least one of a group consisting of "polymer (PAc)", poly-proline, polyimine, and polyphthalate can cause the voltage holding ratio and light resistance of the liquid crystal element to become From a more favorable viewpoint, a polymer (PAc) is more preferable.

・Polymer (PAc) The monomer used for the polymerization of the polymer (PAc) is not particularly limited as long as it has a polymerizable unsaturated bond, and examples thereof include a (meth)acrylic compound and a conjugated diene compound. An aromatic vinyl compound, a maleimide compound, or the like. In view of the high effect of improving the light resistance of the liquid crystal element, the polymer (PAc) is preferably a polymer obtained by using a monomer containing a (meth)acrylic compound as a raw material. When the polymer (PAc) is synthesized, the use ratio of the (meth)acrylic compound is preferably 50% by mole or more, and more preferably 60% by mole or more, based on the total amount of the monomers used for the synthesis. More preferably, it is 70 mol or more. Further, in the present specification, "(meth)acrylic acid" means a meaning including acrylic acid and methacrylic acid.

The polymer (PAc) may have a partial structure exhibiting liquid crystallinity, and have a functional group that induces light to generate a crosslinking reaction, an isomerization reaction, a photodimerization reaction, or a Fries rearrangement reaction (hereinafter referred to as "Photoreactive group"). Examples of the photoreactive group include a (meth)acrylic group containing a (meth)acrylic acid or a derivative thereof, a vinyl group (alkenyl group, a styryl group, etc.), and acetylene. a base, an epoxy group (oxiranyl group, oxetanyl group), a phenyl benzoate-containing group containing phenyl benzoate or a derivative thereof as a basic skeleton, containing azobenzene or a derivative thereof as a basic a azobenzene-containing group of a skeleton, a cinnamic acid-containing group containing cinnamic acid or a derivative thereof as a basic skeleton, a chalcone-containing group containing chalcone or a derivative thereof as a basic skeleton, and a diphenyl group A ketone-containing group having a ketone or a derivative thereof as a basic skeleton, a coumarin-containing group containing coumarin or a derivative thereof as a basic skeleton, and the like.

The polymer (PAc) can be obtained, for example, by polymerizing a monomer having a polymerizable unsaturated bond in the presence of a polymerization initiator. The monomer to be used preferably contains a compound having a polymerizable unsaturated bond and a partial structure exhibiting liquid crystallinity. Specific examples of the monomer having a polymerizable unsaturated bond and a partial structure exhibiting liquid crystallinity include compounds represented by the following formulas (2-1) to (2-5), and the like. Further, these monomers may be used alone or in combination of two or more. [Chemical 3] (In the formulae (2-1) to (2-5), R ² is a hydrogen atom or a methyl group, R ³ is an alkanediyl group having 1 to 12 carbon atoms, or at least -O- is substituted for the alkanediyl group; a divalent group formed by one methylene group, and R ⁴ is an alkyl group having 1 to 20 carbon atoms, an alkoxy group or a fluoroalkyl group, or a fluorine atom)

Further, when the polymer (PAc) is synthesized, a compound having a partial structure exhibiting liquid crystallinity may be used in combination as a monomer having a polymerizable unsaturated bond. The ratio of use of the compound having no partial structure exhibiting liquid crystallinity is preferably 50 mol% or less, and more preferably 40 mol% or less, based on the total amount of the monomers used for the synthesis of the polymer (PAc).

As the polymerization initiator used for the polymerization, for example, 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), An azo compound such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). The use ratio of the polymerization initiator is preferably 0.01 parts by mass to 30 parts by mass based on 100 parts by mass of all the monomers used for the reaction. The polymerization is preferably carried out in an organic solvent. Examples of the organic solvent used for the reaction include an alcohol, an ether, a ketone, a decylamine, an ester, and a hydrocarbon compound. Specific examples thereof include diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether. Acetate, tetrahydrofuran, and the like. The reaction temperature is preferably 30 ° C to 120 ° C, and the reaction time is preferably 1 hour to 36 hours. The amount (a) of the organic solvent to be used is preferably such that the total amount of the monomers used for the reaction (b) is 0.1% by mass to 60% by mass based on the total amount (a+b) of the reaction solution.

The polystyrene-equivalent weight average molecular weight (Mw) of the polymer (PAc) measured by Gel Permeation Chromatography (GPC) is preferably 250 to 500,000, more preferably 500 to 100,000, still more preferably 1,000 to 1,000. 50,000. Further, the polymer (PAc) may be used alone or in combination of two or more.

・Polyuric acid as the polymer (A) (hereinafter also referred to as "polyglycine (A)") is not particularly limited as long as it exhibits liquid crystallinity, but can be preferably used. It has a liquid crystal original structure in the main chain of the polymer. When such a polyamic acid is to be obtained, for example, at least one of a tetracarboxylic dianhydride having a liquid crystal original structure in a main chain and a diamine compound having a liquid crystal original structure in a main chain can be used. It is obtained by polymerization of raw materials. An example of a polyamic acid exhibiting liquid crystallinity is a polymer obtained by reacting a tetracarboxylic dianhydride having a terphenyl skeleton in a main chain with a diamine compound, and specifically, A polymer having a partial structure represented by the following formula (3). [Chemical 4] (In the formula (3), R ⁵ is a divalent organic group)

In the formula (3), the divalent organic group of R ⁵ is a group remaining after removing two primary amino groups from the diamine compound. From the viewpoint of exhibiting liquid crystallinity of polyglycine, R ⁵ is preferably a linear alkanediyl group having 4 to 20 carbon atoms or a divalent group containing -O- between carbon-carbon bonds of the alkanediyl group. Base.

The tetracarboxylic dianhydride used for the synthesis of the polyamic acid (A) may be only a tetracarboxylic dianhydride having a liquid crystal original structure, but a tetracarboxylic dianhydride having no liquid crystal original structure may be used in combination. The tetracarboxylic dianhydride is not particularly limited, and a known tetracarboxylic dianhydride can be used. When a poly-proline which exhibits liquid crystallinity is synthesized, the ratio of use of the tetracarboxylic dianhydride having a liquid crystal original structure is preferably 50% by mole or more based on the total amount of the tetracarboxylic dianhydride used for the synthesis. More preferably, it is 70 mol% or more.

Examples of the diamine compound used for the synthesis of the polyamic acid (A) include an aliphatic diamine, an alicyclic diamine, an aromatic diamine, and a diaminoorganosiloxane. Among these, an aliphatic diamine can be preferably used, and an alkylenediamine such as 1,4-diaminobutane, hexamethylenediamine or octamethylenediamine is more preferable. When the polyamic acid (A) is synthesized, the ratio of the alkylene diamine to be used is preferably 50% by mole or more, and more preferably 60% by mole or more based on the total amount of the diamine compound used for the synthesis. .

The polyamic acid (A) can be obtained by reacting the tetracarboxylic dianhydride and the diamine compound as described above together with a molecular weight modifier. The ratio of the tetracarboxylic dianhydride to the diamine compound to be used in the synthesis reaction of the polyamic acid is preferably 1 equivalent to the amino group of the diamine compound, and the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 2 equivalents. Examples of the molecular weight modifier include acid monoanhydrides such as maleic anhydride and phthalic anhydride, monoamine compounds such as aniline, cyclohexylamine, and n-butylamine, and phenyl isocyanate and isocyanate. a monoisocyanate compound such as an ester. The use ratio of the molecular weight modifier is preferably 20 parts by mass or less based on 100 parts by mass of the total of the tetracarboxylic dianhydride and the diamine compound.

The synthesis reaction of polyamic acid (A) is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, and the reaction time is preferably 0.1 hour to 24 hours. Examples of the organic solvent used for the reaction include an aprotic polar solvent, a phenol-based solvent, an alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, and a hydrocarbon. A particularly preferred organic solvent will preferably be selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl hydrazine, gamma-butene One or more of the group consisting of ester, tetramethylurea, hexamethylphosphonium triamine, m-cresol, xylenol, and halogenated phenol is used as a solvent, or one or more of these organic solvents are used together with other organic solvents. (for example, a mixture of butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount (a) of the organic solvent to be used is preferably such an amount that the total amount (b) of the tetracarboxylic dianhydride and the diamine is from 0.1% by mass to 50% by mass based on the total amount (a+b) of the reaction solution. In the manner described, a reaction solution obtained by dissolving polyamic acid (A) can be obtained. The reaction solution may be directly supplied to the preparation of the liquid crystal alignment agent, or may be supplied to the liquid crystal alignment agent after the polyamic acid contained in the reaction solution is isolated.

・Polyurinate as the polyamine amide of the polymer (A) can be obtained, for example, by a method such as polyaminic acid (A) obtained by the synthesis reaction and an esterifying agent ( For example, a method of performing a reaction such as an alcohol; a method of reacting a tetracarboxylic acid diester with a diamine compound; and a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound. The obtained polyamidite may have only a phthalate structure, or may be a partial ester compound in which a valeric acid structure and a phthalate structure coexist. Further, the reaction solution obtained by dissolving the polyglycolate may be directly supplied to the preparation of the liquid crystal alignment agent, or may be supplied to the liquid crystal alignment agent after isolating the polyphthalate contained in the reaction solution.

Polyimine A polyimine which is a polymer (A) can be obtained, for example, by subjecting polylysine (A) synthesized in the above manner to dehydration ring closure. The polyimine may be a fully ruthenium imide formed by dehydration ring closure of all of the proline structure of the polyglycolic acid as its precursor, or may be dehydrated only for a part of the proline structure. A closed-loop, partial yttrium imide that has a valeric acid structure and a quinone ring structure. The ruthenium imidization ratio of the polyimine used for the reaction is preferably 20% to 99%, more preferably 30% to 90%. The ruthenium imidization ratio is expressed as a percentage of the total amount of the quinone ring structure relative to the total number of phthalic acid structures of the polyimine and the total number of quinone ring structures.

The dehydration ring closure of polylysine is carried out, for example, by dissolving polylysine in an organic solvent, adding a dehydrating agent and a dehydration ring-closure catalyst to the solution, and heating as necessary. As the dehydrating agent, for example, an acid anhydride such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably from 0.01 mol to 20 mol based on 1 mol of the proline structure of the polyglycolic acid. As the dehydration ring-closing catalyst, for example, a tertiary amine such as pyridine, trimethylpyridine, lutidine or triethylamine can be used. The amount of the dehydration ring-closure catalyst used is preferably set to 0.01 mol to 10 mol with respect to 1 mol of the dehydrating agent to be used. The organic solvent used for the dehydration ring-closure reaction is exemplified as the organic solvent exemplified as the organic solvent used in the synthesis of polyglycine. The reaction temperature of the dehydration ring closure reaction is preferably from 0 ° C to 180 ° C. The reaction time is preferably from 1.0 hour to 120 hours. A reaction solution containing polyiminoimine can be obtained in the manner described. The reaction solution may be directly supplied to the preparation of the liquid crystal alignment agent, or may be supplied to the preparation of the liquid crystal alignment agent after the polyimine is isolated.

When a solution having a concentration of 10% by mass is prepared, the solution viscosity of the polyglycolic acid, polyphthalate, and polyimine as the polymer (A) is preferably a solution having a concentration of 10 mPa·s to 800 mPa·s. The viscosity is more preferably a solution viscosity of 15 mPa·s to 500 mPa·s. Further, the solution viscosity (mPa·s) is a polymer solution having a concentration of 10% by mass prepared for a good solvent (for example, γ-butyrolactone or N-methyl-2-pyrrolidone) using these polymers. The value measured at 25 ° C using an E-type rotational viscometer. The polystyrene-reduced weight average molecular weight (Mw) measured by GPC of polyglycine, polyphthalate, and polyimine is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. In addition, the molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 15 or less, more preferably 10 or less.

The temperature range in which the polymer (A) exhibits liquid crystallinity (hereinafter also referred to as "liquid crystal temperature range") is not particularly limited, but the viewpoint of the alignment control force and the alignment stability of the obtained liquid crystal alignment film is sufficiently improved. The liquid crystal temperature range is preferably in the range of from 90 ° C to 380 ° C, more preferably in the range of from 100 ° C to 350 ° C.

<Polyorganooxane (C)> The photo-alignment group of the polyorganosiloxane (C) is a photo-isomerization reaction, a photodimerization reaction, or a photodecomposition reaction caused by light irradiation. An anisotropic functional group is imparted. The polyorganosiloxane (C) may have a photo-alignment group on either of the main chain and the side chain, but a photo-alignment group having a side chain may be preferably used. Specific examples of the photo-alignment group of the polyorganosiloxane (C) include the azobenzene-containing group, the cinnamic acid-containing group, the chalcone-containing group, and the diphenyl group. A ketone group, a coumarin-containing group, and the like. Among these, a group containing a cinnamic acid structure is preferred from the viewpoint of high light sensitivity and easy introduction into a side chain. In particular, the cinnamic acid-containing structure of the polyorganosiloxane (C) is preferably selected from the group consisting of a group represented by the following formula (cn-1) and a group represented by the following formula (cn-2). At least one of the groups. [Chemical 5] (In the formula (cn-1), R ¹¹ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a cyano group. R ¹² is a phenyl group and a biphenyl group. a group, a stretching terphenyl group or a cyclohexylene group, or a group in which at least a part of hydrogen atoms of the group is substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms or a cyano group A ¹¹ is a single bond, an oxygen atom, a sulfur atom, an alkyldiyl group having 1 to 3 carbon atoms, -CH=CH-, -NH-, * ¹ -COO-, * ¹ -OCO-, * ¹ -NH- CO-, * ¹ -CO-NH-, * ¹ -CH ₂ -O- or * ¹ -O-CH ₂ - ("* ¹ " represents a bond with R ¹² ). R ¹³ is a halogen atom, carbon number An alkyl group of 1 to 3, an alkoxy group having 1 to 3 carbon atoms or a cyano group. a is 0 or 1, and b is an integer of 0 to 4. When b is 2 or more, a plurality of R ¹³ may be the same. Can also be different. "*" means the binding key) [Chem. 6] (In the formula (cn-2), R ¹⁴ is a monovalent organic group having 1 to 20 carbon atoms. R ¹⁵ is a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or cyanide. A ¹² is an oxygen atom, * ¹ -COO-, * ¹ -OCO-, * ¹ -NH-CO- or * ¹ -CO-NH- ("* ¹ " represents a bond with R ¹⁶ ). ¹⁶ is an alkyldiyl group having 1 to 6 carbon atoms. c is 0 or 1, and d is an integer of 0 to 4. When d is 2 or more, plural R ^{15 's} may be the same or different. "*" indicates Binding key)

Examples of the monovalent organic group of R ¹⁴ include an alkyl group having 1 to 3 carbon atoms, -R ²¹ -X ² -R ²² and -R ²² (R ²¹ is a substituted or unsubstituted phenylene group). Or a cyclohexyl group, R ²² is a substituted or unsubstituted phenyl or cyclohexyl group, X ² is a single bond, an oxygen atom, a sulfur atom, an alkyldiyl group having 1 to 3 carbon atoms, -CH=CH-, - NH-, -COO-, -NH-CO- or -CH ₂ -O-), and the like. Examples of the substituent of R ²¹ and R ²² include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a cyano group.

The method of synthesizing the polyorganosiloxane (C) is not particularly limited. As an example, a method of hydrolyzing and condensing a hydrolyzable decane compound containing an epoxy group and another decane compound, and then reacting a carboxylic acid having a photo-alignment group, may be mentioned. Examples of the epoxy group-containing decane compound include 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropylmethyldimethoxydecane, and 3-glycidoxypropyl group. Triethoxy decane, 3-glycidoxypropylmethyldiethoxy decane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, and the like. The other decane compound is not particularly limited as long as it is a hydrolyzable compound, and examples thereof include tetramethoxy decane, methyl triethoxy decane, phenyl trimethoxy decane, and p-styryl trimethoxy group. Decane, vinyltriethoxydecane, 3-mercaptopropyltriethoxydecane, 3-aminopropyltrimethoxydecane, 3-(methyl)propenyloxypropyltrimethoxydecane, trimethoxy Based on alkyl propyl succinic anhydride and the like. Further, the decane compound may be used singly or in combination of two or more.

The hydrolysis/condensation reaction is preferably carried out by reacting one or two or more decane compounds with water in the presence of a suitable catalyst and an organic solvent. In the reaction, the ratio of use of water is preferably from 1 mole to 30 moles per mole of the decane compound (total amount). Examples of the catalyst to be used include an acid, an alkali metal compound, an organic base, a titanium compound, and a zirconium compound. The amount of the catalyst to be used varies depending on the type of the catalyst, the reaction conditions such as the temperature, and the like, and is, for example, 0.01 to 3 times moles based on the total amount of the decane compound. Examples of the organic solvent to be used include a hydrocarbon, a ketone, an ester, an ether, and an alcohol. It is preferred to use an organic solvent which is not water-soluble or poorly water-soluble. The use ratio of the organic solvent is preferably 10 parts by mass to 10,000 parts by mass based on 100 parts by mass of the total of the decane compound used for the reaction. Further, the reaction is preferably carried out by heating with an oil bath or the like. In this case, the heating temperature is preferably 130 ° C or lower, and the heating time is preferably 0.5 hours to 12 hours. After completion of the reaction, the organic solvent layer separated from the reaction liquid is dried with a desiccant as necessary, and then the solvent is removed to obtain an epoxy group-containing polyorganosiloxane.

The reaction of the epoxy group-containing polyorganosiloxane with the carboxylic acid is preferably carried out in the presence of a catalyst and an organic solvent. The proportion of the carboxylic acid to be used is preferably 5 mol% or more, and more preferably 10 mol% to 80 mol%, based on the epoxy group of the polyorganosiloxane having an epoxy group. As the catalyst, for example, an organic base or a compound known as a so-called hardening accelerator for promoting the reaction of an epoxy compound can be used. The use ratio of the catalyst is preferably 100 parts by weight or less based on 100 parts by weight of the polyoxyalkylene group containing an epoxy group. Preferable specific examples of the organic solvent to be used include 2-butanone, 2-hexanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and butyl acetate. The organic solvent is preferably used in a ratio of a solid content concentration of 5 to 50% by weight. The reaction temperature in the reaction is preferably 0 ° C to 200 ° C, and the reaction time is preferably 0.1 hour to 50 hours. After completion of the reaction, the organic solvent layer separated from the reaction liquid is dried with a desiccant as necessary, and then the solvent is removed to obtain a polyorganosiloxane (C) having a photoalignment group. In addition, the synthesis method of the polyorganosiloxane (C) is not limited to the hydrolysis/condensation reaction, and may be carried out, for example, by a method in which a hydrolyzable decane compound is reacted in the presence of oxalic acid or an alcohol. Further, when a polyorganosiloxane having a photo-alignment group in a side chain is to be obtained, a method of using a hydrolyzable decane compound having a photo-alignment group for polymerization of a raw material may also be employed.

The polyorganosiloxane (C) has a polystyrene-equivalent weight average molecular weight measured by GPC of preferably 500 to 1,000,000, more preferably 1,000 to 100,000, still more preferably 1,000 to 50,000. Further, the polyorganosiloxane (C) may be used singly or in combination of two or more.

The liquid crystal alignment agent of the present invention preferably contains at least one polymer selected from the group consisting of polylysine, polyphthalate, and polyimine in the polymer component. The polymer may be a polymer (A) which exhibits liquid crystallinity in a predetermined temperature range, or may be a polymer which does not exhibit liquid crystallinity. A preferred embodiment of the liquid crystal alignment agent of the present invention further contains at least one selected from the group consisting of polylysine, polyphthalate, and polyimine, and is a non-liquid crystalline polymer ( Hereinafter, it is also referred to as "polymer (B)") as a polymer component. By including such a polymer (B), it is preferable from the viewpoint of improving the initial voltage holding ratio and the light resistance of the liquid crystal element.

Polylysine (hereinafter also referred to as "polyperglycine (B)")) as the polymer (B) can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine compound. Specific examples of the tetracarboxylic dianhydride used for the synthesis of polyphthalic acid include, as the aliphatic tetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride and ethylenediamine. Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,3-dimethyl-1,2,3. 4-cyclobutane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a, 4,5,9b - tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b - tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene -1,2-dicarboxylic anhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclohexanetetracarboxylic dianhydride, etc.; Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, and p-phenylene bis(trimellitic acid monoester). Anhydride), ethylene glycol bis (dehydrated trimellitate), 1,3-propanediol bis (dehydrated trimellitate), and the like; in addition, Japanese Patent Laid-Open Publication No. 2010-97188 can be used. Described tetracarboxylic dianhydride. Further, the tetracarboxylic dianhydride may be used alone or in combination of two or more.

Specific examples of the diamine compound used for the synthesis of the polyamic acid (B) include, as the aliphatic diamine, m-xylylenediamine, 1,3-propanediamine, hexamethylenediamine, and the like. Examples of the alicyclic diamine include 1,4-diaminocyclohexane and 4,4′-methylenebis(cyclohexylamine); and examples of the aromatic diamine include dodecyloxy Diaminobenzene, octadecyloxydiaminobenzene, cholestyloxydiaminobenzene, cholesteneoxydiaminobenzene, cholesteryl diaminobenzoate, cholesteryl diaminobenzoate Ester, lanthanum alkyl diaminobenzoate, 3,6-bis(4-aminobenzylideneoxy)cholesterane, 1,1-bis(4-((aminophenyl)methyl)phenyl -4-butylcyclohexane, 2,5-diamino-N,N-diallylaniline, a side chain type diamine such as a compound represented by the following formula (E-1): ] (In the formula (E-1), X ^I and X ^II are each independently a single bond, -O-, -COO- or -OCO-, R ^I is an alkanediyl group having 1 to 3 carbon atoms, and R ^II is a single A bond or an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, b is an integer of 0 to 2, c is an integer of 1 to 20, and d is 0 or 1. wherein a and b are different at 0)

P-phenylenediamine, 4,4'-diaminodiphenylmethane, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 1,5-bis (4 -aminophenoxy)pentane, bis[2-(4-aminophenyl)ethyl]hexanedicarboxylic acid, N,N-bis(4-aminophenyl)methylamine, 2,6-diamino Pyridine, 1,4-bis-(4-aminophenyl)-pyridazine, N,N'-bis(4-aminophenyl)-benzidine, 2,2'-dimethyl-4,4'- Diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, diaminobenzoic acid, 4,4'-diaminodiphenyl ether, 2,2-double [4-(4-Aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(phenylphenyldiisopropylidene)diphenylamine, 4-(4-Aminophenoxycarbonyl)-1-(4-aminophenyl)acridine, 4,4'-[4,4'-propane-1,3-diylbis(acridine-1, 4-diyl)]diphenylamine, a main chain type diamine such as a diamine containing a cinnamic acid structure; and as the diaminoorganosiloxane, for example, 1,3-bis(3-aminopropyl)-tetramethyl Dioxane or the like; in addition to the above, a diamine described in JP-A-2010-97188 can be used. Further, the diamine compounds may be used alone or in combination of two or more.

The polyamic acid (B) can be obtained by reacting the tetracarboxylic dianhydride and the diamine compound as described above together with a molecular weight modifier. The description of the polyamic acid (A) can be applied to the molecular weight modifier, the polymerization solvent, the reaction conditions and the like used in the reaction. The polyperurethane and the polyimide as the polymer (B) can be the same as in the case of the polymer (A), for example, except that polyglycolic acid (B) is used instead of the polyamic acid (A). Way to get. Regarding the solution viscosity, the weight average molecular weight, and the number average molecular weight of the polymer (B), the description of the polymer (A) is applied.

The polymer component in the liquid crystal alignment agent of the present invention is preferably any one of the following [1] to [4]. [1] A form in which the polymer (A) and the polyorganosiloxane (C) are contained as a polymer component, and the polymer (A) is a polymer (PAc). [2] comprising a polymer (A) and a polyorganosiloxane (C) as a polymer component, and the polymer (A) is selected from the group consisting of polylysine, polyphthalate and polyimine. The form of at least one of the groups. [3] A form in which the polymer (A), the polymer (B), and the polyorganosiloxane (C) are contained as a polymer component, and the polymer (A) is a polymer (PAc). [4] comprising a polymer (A), a polymer (B) and a polyorganosiloxane (C) as a polymer component, and the polymer (A) is selected from the group consisting of polyglycine, polyglycolate and poly A form of at least one of the group consisting of quinone imines. Among these, from the viewpoints of the initial voltage holding ratio and light resistance of the liquid crystal element, [1] and [3] are more preferable, and [3] is particularly preferable. Further, the polymer (A) and the polymer (B) may be photosensitive for exposure to exhibit anisotropy of polyorganosiloxane (C) by light induction, or may be The exposure is non-photosensitive. From the viewpoint of the initial voltage holding ratio and light resistance of the liquid crystal element, non-photosensitivity is preferable.

In the liquid crystal alignment agent of the present invention, the content ratio of the polymer (A) and the polyorganosiloxane (C) is sufficient to obtain an effect of improving the initial voltage holding ratio and the light resistance of the liquid crystal element. 100 parts by mass of the total of the polymer components contained in the liquid crystal alignment agent, the polymer (A) is preferably 1 part by mass to 80 parts by mass, more preferably 3 parts by mass to 70 parts by mass, still more preferably 5 parts by mass. Parts by mass to 60 parts by mass. The polyorganosiloxane (C) is preferably from 1 part by mass to 99 parts by mass, more preferably from 5 parts by mass to 95 parts by mass, based on 100 parts by mass of the total of the polymer component contained in the liquid crystal alignment agent. More preferably, it is 10 mass parts - 90 mass parts. Further, the ratio of the polymer (A) to the polyorganosiloxane (C) is preferably a polymer (A): polyorganosiloxane (C) = 5:95 to 70:30, by mass ratio. It is preferably set to 10:90 to 60:40. When the polymer (B) is blended in the liquid crystal alignment agent of the present invention, the content of the polymer (B) is preferably 1 part by mass based on 100 parts by mass of the total of the polymer components contained in the liquid crystal alignment agent. 95 parts by mass, more preferably 20 parts by mass to 90 parts by mass, still more preferably 40 parts by mass to 80 parts by mass.

The liquid crystal alignment agent of the present invention may contain a polymer (A), a polyorganosiloxane (C), and other components other than the polymer (A) and the polyorganosiloxane (C). Examples of the other component include, in addition to the polymer (B), a polymer other than the polymer (A), the polymer (B), and the polyorganosiloxane (C), and at least one epoxy group in the molecule. Compounds, functional decane compounds, antioxidants, metal chelating compounds, hardening accelerators, surfactants, fillers, dispersants, photosensitizers, and the like. The compounding ratio of the other components can be appropriately selected in accordance with the respective compounds within the range which does not impair the effects of the present disclosure.

(Solvent) The liquid crystal alignment agent of the present invention is prepared as a liquid composition in which a polymer component and, if necessary, other components are preferably dispersed or dissolved in a suitable solvent. Examples of the organic solvent to be used include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, and γ. - butane amide, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, Butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol -isopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethyl Alcohol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diiso Butyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate and the like. These organic solvents may be used alone or in combination of two or more.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., but is preferably 1 mass. A range of % to 10% by mass. In other words, the liquid crystal alignment agent is applied onto the surface of the substrate as described later, and is preferably heated to form a coating film as a liquid crystal alignment film or a coating film to be a liquid crystal alignment film. At this time, when the solid content concentration is less than 1% by mass, the film thickness of the coating film becomes too small, and it is difficult to obtain a favorable liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by mass, the film thickness of the coating film becomes too large, and it is difficult to obtain a favorable liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases and the coating property tends to decrease.

<Liquid Crystal Element> The liquid crystal element of the present invention includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied, for example, to a twisted nematic (TN) type, a super twisted nematic (STN) type, or a vertical alignment type (including vertical alignment (vertical alignment). Alignment, VA) - Multi-Domain Vertical Alignment (MVA) type, VA-Patterned Vertical Alignment (PVA) type, In-Plane Switching (IPS) type, edge Various modes such as Fringe Field Switching (FFS) type and Optically Compensated Bend (OCB) type. The liquid crystal element can be produced, for example, by a method including the following steps 1 to 3. In step 1, the use of the substrate differs depending on the desired mode of operation. Steps 2 and 3 are shared for each operation mode.

[Step 1: Formation of Coating Film] First, a liquid crystal alignment agent is applied onto a substrate, and then, the coated surface is heated as necessary to form a coating film on the substrate. As the substrate, for example, glass such as float glass or soda glass can be used; and polyethylene terephthalate, polybutylene terephthalate, polyether oxime, polycarbonate, poly(alicyclic olefin) can be used. A transparent substrate such as plastic. As the transparent conductive film provided on one side of the substrate, a NESA film containing tin oxide (SnO ₂ ) (registered trademark of PPG, USA) and an oxidation containing indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) can be used. Indium Tin Oxide (ITO) film or the like. When a TN type, STN type, or vertical alignment type liquid crystal element is manufactured, two sheets of a substrate provided with a patterned transparent conductive film are used. When a horizontal electric field type liquid crystal element such as an IPS type or an FFS type is manufactured, a substrate including an electrode including a transparent conductive film or a metal film patterned into a comb shape, and a counter substrate not provided with an electrode are used. As the metal film, for example, a film containing a metal such as chromium can be used. The coating onto the substrate is performed on the electrode forming surface, preferably by a lithography method, a spin coating method, a roll coater method, or an inkjet printing method.

After the liquid crystal alignment agent is applied, in order to prevent sag of the applied liquid crystal alignment agent or the like, preheating (prebaking) is preferably performed. The prebaking temperature is preferably from 30 ° C to 200 ° C, and the prebaking time is preferably from 0.25 minutes to 10 minutes. Thereafter, the solvent is completely removed, and if necessary, a calcination (post-baking) step is carried out for the purpose of thermally imidating the proline structure present in the polymer. The calcination temperature (post-baking temperature) at this time is preferably 80 to 300 ° C, and the post-baking time is preferably 5 to 200 minutes. The film thickness of the film formed in the above manner is preferably 0.001 μm to 1 μm.

[Step 2: Orientation treatment] When a liquid crystal element of a TN type, an STN type, an IPS type or an FFS type is produced, a treatment (alignment treatment) for imparting a liquid crystal alignment ability to the coating film formed in the above step 1 is performed. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to become a liquid crystal alignment film. The alignment treatment may be a rubbing treatment in which a coating film is rubbed in a fixing direction by a roll in which a cloth comprising fibers such as nylon, rayon, or cotton is wound, thereby imparting a liquid crystal alignment ability to the coating film; The substrate surface coated with the liquid crystal alignment agent is subjected to light irradiation to impart a liquid alignment treatment capability to the coating film. From the viewpoint of imparting sufficient liquid crystal alignment control force to the light irradiation of the coating film, or suppressing the occurrence of display failure or the decrease in yield due to generation of dust or static electricity, etc., it is possible to form the substrate. The liquid crystal alignment agent of the present disclosure can preferably be applied with a photoalignment treatment from the viewpoint of uniformly imparting a liquid crystal alignment ability to the above organic film. When a vertical alignment type liquid crystal element is manufactured, the coating film formed in the above step 1 can be directly used as a liquid crystal alignment film, but the coating film may be subjected to an alignment treatment.

In the light alignment treatment, for the light to be applied to the coating film, for example, ultraviolet rays and visible rays containing light having a wavelength of 150 nm to 800 nm can be used. Ultraviolet light containing light having a wavelength of 200 nm to 400 nm is preferred. When the irradiation light is linearly polarized or partially polarized, the substrate surface may be irradiated from the vertical direction, or the substrate surface may be irradiated from the oblique direction, or both may be combined. When the non-polarized radiation is irradiated, the direction of the irradiation is set to the oblique direction. As the light source to be used, for example, a low pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser or the like can be used. The ultraviolet light in a preferred wavelength region can be obtained by a method in which a light source is used in combination with, for example, a filter, a diffraction grating, or the like. The irradiation amount of the radiation is preferably 200 J/m ² to 50,000 J/m ² , and more preferably 400 J/m ² to 20,000 J/m ² . The coating film after the post-baking step may be irradiated with light for imparting an alignment ability, or the coating film before the pre-baking step and before the post-baking step may be irradiated with light for imparting an alignment ability, or may be In at least one of the prebaking step and the post-baking step, the coating film is subjected to light irradiation for imparting an alignment ability during heating.

[Step 3: Construction of Liquid Crystal Cell] Two substrates in which the liquid crystal alignment film was formed as described above were prepared, and liquid crystal was placed between the two substrates arranged in the opposite direction to manufacture a liquid crystal cell. Specifically, a method of sealing the injection hole by injecting a liquid crystal into the cell gap defined by the surface of the substrate and the sealant by bonding the peripheral portion of the pair of substrates to each other by a sealant; It is applied to the peripheral portion of the liquid crystal alignment film side of one substrate, and the liquid crystal is dropped onto a predetermined number of portions on the liquid crystal alignment film surface, and then the other substrate is bonded to the liquid crystal alignment film in the opposite direction, and the liquid crystal is extruded. A method in which pressure is diffused to the entire surface of the substrate, followed by hardening of the sealant (One Drop Fill (ODF) method). Examples of the sealant include an epoxy resin containing a curing agent and an alumina ball as a spacer. Examples of the liquid crystal include a nematic liquid crystal and a smectic liquid crystal. Among them, a nematic liquid crystal is preferable, and examples thereof include a Schiff base liquid crystal, an azoxy liquid crystal, and a biphenyl liquid crystal. A phenylcyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, a biphenyl cyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cuba liquid crystal, or the like. Further, a cholesteric liquid crystal, a chiral agent, a ferroelectric liquid crystal or the like may be added to these liquid crystals for use.

In the step 3, a liquid crystal cell containing a polymerizable monomer in the liquid crystal layer is formed, and the liquid crystal cell is irradiated with light to polymerize the polymerizable monomer to provide an initial liquid crystal. Orientation. By applying this treatment, when applied to a horizontal electric field type such as an IPS type or an FFS type, it is preferable to obtain a liquid crystal element having a high initial voltage holding ratio and excellent light resistance.

As the polymerizable monomer, a compound having two or more (meth)acryl fluorenyl groups can be preferably used from the viewpoint of high polymerizability due to light. Specific examples thereof include a di(meth)acrylate having a biphenyl structure, a di(meth)acrylate having a phenyl-cyclohexyl structure, and a second having a 2,2-diphenylpropane structure. (meth) acrylate, di(meth) acrylate having a diphenylmethane structure, di-thio (meth) acrylate having a diphenyl sulfide structure, di(meth)acrylic acid having a naphthalene structure An ester, a di(meth)acrylate having an anthracene structure, a di(meth)acrylate having a phenanthrene structure, a di(meth)acrylate having a structure in which a radical is generated by light irradiation, or the like. The blending ratio of the polymerizable monomer is preferably from 0.1% by mass to 1.0% by mass based on the total amount of the liquid crystal composition for forming the liquid crystal layer. Further, the polymerizable monomers may be used singly or in combination of two or more.

The light irradiation of the liquid crystal cell may be performed in a state where no voltage is applied between the pair of electrodes, or may be performed in a state where a predetermined voltage (for example, 0 V) in which the liquid crystal molecules in the liquid crystal layer are not driven is applied, or This is carried out in a state where a predetermined voltage driven by the liquid crystal molecules is applied. When the liquid crystal alignment agent of the present invention is applied to a liquid crystal element having a liquid crystal cell of a horizontal electric field type, it is preferable to irradiate the liquid crystal cell with light without applying a voltage between the pair of electrodes. As the light to be irradiated, for example, ultraviolet rays and visible rays containing light having a wavelength of 150 nm to 800 nm can be used, and ultraviolet rays containing light having a wavelength of 300 nm to 400 nm are preferable. In the case where the radiation to be used is linearly polarized or partially polarized, the substrate surface may be irradiated from the vertical direction, or the substrate surface may be irradiated from the oblique direction, or both may be combined. get on. When the non-polarized radiation is irradiated, the irradiation direction is set to the oblique direction.

As the light source for the irradiation light, for example, a low pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser or the like can be used. Again. The ultraviolet light in the preferred wavelength region can be obtained by a method in which a light source is used in combination with, for example, a filter, a diffraction grating, or the like. The irradiation amount of light is preferably 1,000 J/m ² to 200,000 J/m ² , and more preferably 1,000 J/m ² to 100,000 J/m ² .

Instead of mixing a polymerizable monomer into the liquid crystal layer, the polymerizable monomer may be mixed with the liquid crystal layer, and the liquid crystal cell may be subjected to light irradiation to thereby impart initial alignment to the liquid crystal. In this case, in the step 1, a coating film is formed on the substrate using a liquid crystal alignment agent containing a polymerizable monomer. The description of the polymerizable monomer contained in the liquid crystal layer is applied as the polymerizable monomer contained in the liquid crystal alignment agent. The content ratio of the polymerizable monomer is preferably from 1 part by mass to 100 parts by mass, and more preferably from 5 parts by mass to 50 parts by mass, per 100 parts by mass of the total of the polymer component contained in the liquid crystal alignment agent.

Then, a polarizing plate is attached to the outer surface of the liquid crystal cell as needed, whereby a liquid crystal element can be obtained. Examples of the polarizing plate include a polarizing plate in which a polarizing film called “H film” is sandwiched by a cellulose acetate protective film, or a polarizing plate including an H film itself, and the “H film” is made of polyethylene. The alcohol extends to the side to absorb iodine.

The liquid crystal element of the present disclosure can be effectively applied to various applications such as a clock, a portable game machine, a word processor, a notebook personal computer, a car navigation system, a camcorder, and a personal digital assistant (Personal Digital Assistant, PDA), digital cameras, mobile phones, smart phones, various monitors, LCD TVs, information displays, and other display devices, or dimming films. Further, a liquid crystal element formed using the liquid crystal alignment agent of the present disclosure can also be applied to a retardation film. [Examples]

Hereinafter, the embodiment will be more specifically described, but the present invention is not limited to these examples.

In the following examples, the weight average molecular weight Mw and the epoxy equivalent of the polymer were measured by the following methods. [Weight average molecular weight Mw of the polymer]: As a result of measurement by gel permeation chromatography under the following conditions, monodisperse polystyrene was used as a standard substance as a polystyrene equivalent value by the following apparatus. To find out. Measuring device: manufactured by Tosoh (share), model "8120-GPC" Pipe column: manufactured by Tosoh (stock), "TSKgelGRCXLII" Solvent: tetrahydrofuran sample concentration: 5 wt% sample injection amount: 100 μL tube Column temperature: 40 ° C Column pressure: 68 kgf / cm ² [Epoxy equivalent]: Measured in accordance with "Hydro-methyl ethyl ketone method" of JIS C2105.

<Synthesis of Polymer (A)> [Synthesis Example 1] A compound represented by the following formula (m-1) was dissolved in tetrahydrofuran, and azobisisobutyronitrile as a polymerization initiator was added thereto for polymerization. Thus, a solution containing the polymer (A-1) was obtained. The polymer solution in the system was subjected to solvent replacement with N-methyl-2-pyrrolidone (NMP) for the obtained polymer solution to obtain a polymer (A-1). The polymer (A-1) exhibits liquid crystallinity in a temperature range of from 116 ° C to 315 ° C. [化8] [Synthesis Example 2] The same operation as in Synthesis Example 1 was carried out except that the compound represented by the following formula (m-2) was used instead of the compound represented by the above formula (m-1). Polymer (A-2). The polymer (A-2) exhibits liquid crystallinity in a temperature range of from 108 ° C to 313 ° C. [Chemistry 9] [Synthesis Example 3] 1,009-diaminooctane 0.7009 g (4.858 mmol) was dissolved in 22.5 g of N-methyl-2-pyrrolidone (NMP), and added at room temperature by the following formula (m- 3) The compound represented is 1.7991 g (4.858 mmol). After stirring at 60 ° C for 2 hours, it was cooled to room temperature to obtain a solution containing the polymer (A-3). The obtained polymer solution was poured into a very large amount of methanol to precipitate a reaction product. The precipitate was washed with methanol, and dried at 40 ° C for 15 hours under reduced pressure, whereby a polymer (A-3) was obtained. The polymer (A-3) exhibits liquid crystallinity in a temperature range of from 100 ° C to 235 ° C. [化10]

<Synthesis of Polyorganosiloxane (C)> [Synthesis Example 4] 2-(3,4-epoxycyclohexyl)ethyltrimethyl was added to a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux cooling tube. 100.0 g of oxoxane, 500 g of methyl isobutyl ketone and 10.0 g of triethylamine were mixed at room temperature. Then, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and then mixed under reflux, and reacted at 80 ° C for 6 hours. After completion of the reaction, the organic layer was taken out and washed with a 0.2% by mass aqueous ammonium nitrate solution until the water after washing became neutral, and then the solvent and water were distilled off under reduced pressure to form a viscous transparent liquid. A polymer (EPS-1) as a polyorganosiloxane containing an epoxy group was obtained. The ¹ H-NMR analysis of the polymer (EPS-1) gave a peak based on the oxirane group at a chemical shift (δ) = 3.2 ppm as theoretical strength, and it was confirmed that no epoxy group was produced in the reaction. Side reaction. The polymer (EPS-1) had a weight average molecular weight of 2,200 and an epoxy equivalent of 186 g/mol. Then, 9.3 g of the polymer (EPS-1) obtained above, 26 g of methyl isobutyl ketone, and 3.0 g of a compound represented by the following formula (m-4) were added to a 100 mL three-necked flask, and The product name "UCAT 18X" (a quaternary amine salt manufactured by San-Apro Co., Ltd.) was 0.10 g, and the reaction was carried out at 80 ° C for 12 hours with stirring. After completion of the reaction, the reaction mixture was poured into methanol, and the resulting precipitate was collected and dissolved in ethyl acetate to prepare a solution. After the solution was washed with water three times, the solvent was distilled off, whereby white was obtained. The morphology of the powder was 6.3 g as a polymer (C-1) of polyorganosiloxane (C). The polymer (C-1) had a weight average molecular weight Mw of 3,500. [11]

<Other components> [Synthesis Example 5] 100 parts of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, and 4,4'-diamino group as a diamine 100 parts of diphenyl ether was dissolved in NMP, and reacted at 40 ° C for 3 hours, thereby obtaining a solution containing 10 mass% of the polymer (B-1) as polyglycine. [Synthesis Example 6] 100 mol parts of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, and 4-aminophenyl-4'-amino couple as diamine 100 parts of nitrogen benzene was dissolved in NMP, and reacted at 40 ° C for 3 hours, thereby obtaining a solution containing 10 mass% of the polymer (B-2) as polyglycine. [Synthesis Example 7] A polymer (D-1) was obtained by the same operation as in the above Synthesis Example 1, except that octyl methacrylate was used instead of the compound represented by the above formula (m-1).

[Example 1] (1) Preparation of liquid crystal alignment agent 20 parts by mass of the polymer (A-1) obtained in the synthesis example 1 of the polymer (A), as described for the polymer (B) The solution containing the polymer (B-1) obtained in Synthesis Example 5 is converted into the polymer (B-1) in an amount corresponding to 60 parts by mass, and the synthesis example as the polyorganosiloxane (C). 20 parts by mass of the polymer (C-1) obtained in 4 was mixed, and N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added thereto to prepare a solvent composition of NMP. : BC = 50: 50 (mass ratio), and a solution having a solid concentration of 4.0% by mass. This solution was filtered using a filter having a pore size of 1 μm, thereby preparing a liquid crystal alignment agent. (2) Production of Liquid Crystal Display Element Two glass substrates each having a transparent electrode containing an ITO film were prepared, and the liquid crystal alignment agent prepared in the above (1) was applied onto the respective transparent electrode faces using a spin coater. Then, after prebaking for 1 minute on a hot plate at 80 ° C, the film was heated at 230 ° C for 30 minutes (post-baking) in an oven in which the inside of the chamber was purged with nitrogen to form a coating having a film thickness of 0.1 μm. membrane. Then, using a Hg-Xe lamp and a Glan-Taylor prism, a surface of each coating film was irradiated with a polarized ultraviolet ray of 500 mJ/cm ² including a bright line of 313 nm from the normal direction of the substrate to prepare a pair. (2 pieces) A substrate having a liquid crystal alignment film. Further, the irradiation amount is a value measured using a photometer that measures with a wavelength of 313 nm. Then, for one of the pair of substrates, an epoxy resin adhesive having an alumina ball having a diameter of 5.5 μm is applied to the outer edge of the surface having the liquid crystal alignment film, and the liquid crystal alignment film faces each other. The pair of substrates are overlapped and crimped to harden the binder. Then, a nematic liquid crystal (manufactured by Merck Co., Ltd., MLC-6221) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photocurable adhesive to produce a liquid crystal cell. Further, a polarizing plate is bonded to the outer surfaces of the substrate of the liquid crystal cell so that the polarizing directions of the two polarizing plates are orthogonal to each other, thereby producing a liquid crystal display element.

(3) Evaluation of initial voltage holding ratio After applying a voltage of 5 V to the liquid crystal display element immediately after the production in (2) at a temperature of 60 ° C with an application time of 60 μsec and a span of 167 msec, The voltage holding ratio (initial voltage holding ratio VH ₁ ) after 167 milliseconds from the release of the application was measured. The measurement device used the product name "VHR-1" manufactured by Toyo Corporation (stock). As a result, in Example 1, VH ₁ = 99.6%. (4) Evaluation of light resistance The liquid crystal display element after measuring the initial voltage holding ratio VH ₁ was irradiated with light for 500 hours using a weather meter using a carbon arc as a light source. The voltage holding ratio was measured in the same manner as in the above (3) with respect to the liquid crystal display element after light irradiation. The value is set to VH _2, VH reduce an amount of ₁ to ₂ VH subtracting the obtained voltage holding ratio is defined as ΔVHR, and the light resistance was evaluated by ΔVHR. As a result, in Example 1, ΔVHR was 0.6%, and the light resistance was good. (5) Evaluation of liquid crystal alignment property The liquid crystal alignment agent prepared in the above (1) was coated and optically aligned in the same manner as in the above (2) on the respective surfaces of a pair of glass substrates on which no electrodes were provided. The liquid crystal alignment film is formed by treatment, and a liquid crystal cell is manufactured in the same manner as the above (2) using a pair of substrates having the liquid crystal alignment film. The obtained liquid crystal cell was observed under crossed nicols, and as a result, uniform liquid crystal alignment without poor alignment was observed. In addition, the presence or absence of the alignment defect (abnormal region) in the change of the light and dark when the voltage of 5 V is turned on and off (applied/released) by the liquid crystal display element obtained in the above (2) is observed by a visual observation. As a result, the liquid crystal display element had no alignment defect over the entire surface, and a uniform alignment change of the liquid crystal caused by voltage application was observed.

[Examples 2 to 8 and Comparative Examples 1 to 11] The types and amounts (parts by mass) of the polymer component used for the preparation of the liquid crystal alignment agent were changed as shown in Table 1 below. The liquid crystal alignment agent was prepared in the same solvent ratio and solid content concentration as in Example 1. Further, the liquid crystal alignment agent used was changed as in the following Table 1, and the exposure wavelengths at the time of photoalignment treatment from Comparative Example 3, Comparative Example 4, Comparative Example 6, and Comparative Example 9 to Comparative Example 11 were from 313 nm. The liquid crystal display element was produced in the same manner as in Example 1 except that the irradiation amount was changed from 5,000 mJ/cm ² to 4,000 mJ/cm ² , and electrical characteristics and light resistance were performed in the same manner as in the first embodiment. Evaluation of properties and liquid crystal alignment. Their results are shown in Table 1 below. Further, under the condition that the polymer (B-1) was irradiated with polarized ultraviolet rays having an open line of 313 nm at 500 mJ/cm ² , no photocleavage reaction occurred in the polymer (B-1). Therefore, the polymer (B-1) corresponds to a non-photosensitive polymer with respect to the polyorganosiloxane (C).

[Example 9] (1) Preparation of liquid crystal composition In a nematic liquid crystal (manufactured by Merck & Co., MLC-6221), as a polymerizable monomer, the following is added to the total amount of the nematic liquid crystal. a mixture of a compound represented by the formula (L-1) and a compound represented by the following formula (L-2) (mass mixing ratio (L-1): (L-2) = 50:50) of 0.5% by mass and The mixing was carried out, whereby the liquid crystal composition LC1 was obtained. [化12]

(2) Production of a horizontal electric field type liquid crystal display device A glass substrate having a metal electrode including chromium in a comb shape on one surface and a counter glass substrate not provided with an electrode are paired, and a liquid crystal is used to align the liquid crystal. Agent E (liquid crystal alignment agent used in Example 4) was applied onto the surface of the glass substrate having the electrode and the surface of the opposite glass substrate, and prebaked on a hot plate at 80 ° C for 1 minute, and then in the library. In an oven which was purged with nitrogen, the film was heated at 200 ° C for 1 hour (post-baking) to form a coating film having a film thickness of 0.1 μm. Then, using a Hg-Xe lamp and a Glan-Taylor prism, a surface of each coating film was irradiated with a polarized ultraviolet ray of 300 mJ/cm ² (optical alignment treatment) including a bright line of 313 nm from the normal direction of the substrate to obtain a liquid crystal alignment film. a pair of substrates. Applying an epoxy resin binder having an alumina ball having a diameter of 5.5 μm to the outer periphery of the surface of the one of the substrates having the liquid crystal alignment film by screen printing to form a liquid crystal of the pair of substrates The alignment film was faced, and the orientation of each of the substrates when the polarized ultraviolet rays were irradiated was superposed and pressed, and the adhesive was thermally cured at 150 ° C for 1 hour. Then, the liquid crystal composition LC1 prepared in the above (1) was filled from the liquid crystal injection port toward the gap between the substrates, and then the liquid crystal injection port was sealed with an epoxy-based adhesive. Then, in order to remove the flow alignment at the time of liquid crystal injection, it is heated at 150 ° C and then slowly cooled to room temperature. Further, ultraviolet rays are applied from the outside of the liquid crystal cell without applying a voltage between the pair of electrodes. (Ultraviolet, UV) light irradiation (irradiation amount: 2,000 mJ/cm ² (λ = 365 nm)). Then, the polarizing plates are bonded to the outer surfaces of the substrate so that the polarizing directions thereof are orthogonal to each other and perpendicular to the direction of the projection of the optical axis of the polarized ultraviolet rays of the liquid crystal alignment film, thereby producing a liquid crystal display element.

(2) Evaluation The electrical properties, light resistance, and liquid crystal alignment properties of the liquid crystal display device produced in the above (1) were evaluated in the same manner as in Example 1. As a result, in this embodiment, VH ₁ = 99.2%, and ΔVHR = 0.3%. Further, the liquid crystal alignment property was also good in the same manner as in the first embodiment.

[Example 10, Comparative Example 12, and Comparative Example 13] The liquid crystal alignment agent used was changed as shown in the following Table 1, and the exposure wavelength at the time of photoalignment treatment was changed from 313 nm to Comparative Example 13 A liquid crystal display element was produced in the same manner as in Example 9 except that the irradiation amount was changed from 500 mJ/cm ² to 4,000 mJ/cm ^{2 at} 365 nm, and electrical characteristics, light resistance, and the like were performed in the same manner as in Example 1. Evaluation of liquid crystal alignment. Their results are shown in Table 1 below.

[Example 11] (1) Preparation of liquid crystal alignment agent 20 parts by mass of the polymer (A-2) obtained in the synthesis example 2 of the polymer (A), as described for the polymer (B) The solution containing the polymer (B-1) obtained in Synthesis Example 5 is converted into the polymer (B-1) in an amount corresponding to 60 parts by mass, and the synthesis example as the polyorganosiloxane (C). 20 parts by mass of the polymer (C-1) obtained in 4 was mixed, and N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added thereto, and further, as a polymerizable monomer, 20 parts by mass of the compound represented by the formula (E-1), and a solution having a solvent composition of NMP:BC=50:50 (mass ratio) and a solid concentration of 4.0% by mass. This solution was filtered using a filter having a pore size of 1 μm, thereby preparing a liquid crystal alignment agent T. [Chemistry 13]

(2) Production and Evaluation of Liquid Crystal Display Element The liquid crystal alignment agent used was set to the liquid crystal alignment agent T prepared in the above (1), and MLC-6221 (manufactured by Merck & Co., Inc.) was used instead of the liquid crystal combination. A liquid crystal display element was produced in the same manner as in Example 9 except that the material LC1 was filled in the gap between the substrates, and electrical characteristics, light resistance, and liquid crystal alignment were evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[Table 1]

As is clear from Table 1, the initial voltage holding ratios of the liquid crystal display elements of Examples 1 to 11 were as high as 98.0% or more. Further, ΔVHR was 0.9% or less, and light resistance was also good. Further, in Examples 1 to 11, the alignment of the liquid crystal was also good. On the other hand, in the liquid crystal alignment agents of Comparative Examples 1 to 13 in comparison with the liquid crystal alignment agents of Examples 1 to 11, at least one of the initial voltage holding ratio and the light resistance was unsatisfactory. In the liquid crystal alignment property, the alignment of the liquid crystal was not observed in Comparative Example 2, and the (meth)acrylic polymer which does not exhibit liquid crystallinity was used instead of the polymer (A) (Comparative Example 5 to Comparative Example 9) In the middle, many alignment defects were observed when the voltage was applied and released. Further, in Comparative Example 10 using a polymer (B-2) as a photosensitive polyaminic acid instead of a photosensitive polyorganosiloxane (C), many alignment defects were also observed. .

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Claims (9)

A liquid crystal alignment agent comprising a polyorganosiloxane (C) having a photo-alignment group, and a polyorganosiloxane (C) and a polymer different from the polyorganosiloxane (C) At least one of the molecules of the molecule contains a partial structure exhibiting liquid crystallinity. The liquid crystal alignment agent according to claim 1, which comprises a polymer (A) exhibiting liquid crystallinity and the polyorganosiloxane (C). The liquid crystal alignment agent according to claim 2, wherein the polymer (A) is a polymer of a monomer having a polymerizable unsaturated bond. The liquid crystal alignment agent according to any one of claims 1 to 3, which comprises at least one selected from the group consisting of polylysine, polyphthalate, and polyamidiamine. Polymer. A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 4. A liquid crystal element comprising the liquid crystal alignment film according to item 5 of the patent application. A method for producing a liquid crystal alignment film, comprising the steps of: applying a liquid crystal alignment agent according to any one of claims 1 to 4 to a substrate to form a coating film, and coating the liquid crystal The substrate surface of the alignment agent is irradiated with light to impart a liquid crystal alignment ability to the coating film. A method for producing a liquid crystal element, comprising: a step of forming a liquid crystal alignment film on a surface of each of a pair of substrates by a method for producing a liquid crystal alignment film according to claim 7; A method of arranging the liquid crystal cells by arranging the pair of substrates via a liquid crystal layer containing a polymerizable monomer, and a step of irradiating the liquid crystal cells with light. A method for producing a liquid crystal element, comprising: forming a liquid crystal alignment on a surface of each of a pair of substrates by a method for producing a liquid crystal alignment film according to claim 7 and using a liquid crystal alignment agent containing a polymerizable monomer a step of forming a liquid crystal cell by arranging the pair of substrates via a liquid crystal layer, and a step of irradiating the liquid crystal cell with light, in such a manner that the respective liquid crystal alignment films face each other.