TWI711671B - Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal element, liquid crystal alignment film and liquid crystal element manufacturing method - Google Patents

Abstract

The present invention provides a liquid crystal alignment agent that can obtain a liquid crystal element excellent in initial voltage retention and light resistance. The liquid crystal alignment agent includes polyorganosiloxane (C) having a photo-alignment group, and at least any one of polyorganosiloxane (C) and a polymer different from polyorganosiloxane (C) The molecule contains a partial structure that exhibits liquid crystallinity.

Description

Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal element, liquid crystal alignment film and liquid crystal element manufacturing method

The invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, a liquid crystal alignment film and a method for manufacturing the 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 applications or use environments, the requirements for the display performance of liquid crystal panels have become stricter. Therefore, various researches on liquid crystal alignment films for improving various characteristics of liquid crystal panels are being conducted (for example, refer to Patent Document 1 and Patent Document 2). Patent Document 1 discloses the use of a photo-aligning agent to form a liquid crystal alignment film. The photo-aligning agent contains a polymer having photo-alignment capability and a polymer exhibiting liquid crystallinity, and the polymer having photo-alignment capability is selected from At least one of the group consisting of polyamide, partially imidized polyamide, and polyimide. In addition, Patent Document 2 discloses that after forming a coating film on a substrate using a photosensitive side chain polymer that exhibits liquid crystallinity, it is irradiated with polarized ultraviolet rays and then heated to form a liquid crystal alignment film. [Prior Art Document] [Patent Document]

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

[Problem to be Solved by the Invention] In the process of use in harsh environments, such as continuous driving for a long time or use in places where light stress exists, as the versatility of liquid crystal elements is expected, the important thing about liquid crystal elements is It is difficult to produce degradation caused by light (such as a decrease in voltage retention) during use, and it can withstand use in harsh environments. In addition, in order to improve the display quality of liquid crystal elements, it is also important to have a high initial voltage retention rate. In view of the recent requirements for higher performance of liquid crystal elements, it is necessary to achieve a high initial voltage retention rate and light resistance. New technology of excellent liquid crystal element.

The present invention was made in view of the above-mentioned problems, and one of its objects is to provide a liquid crystal alignment agent that can obtain a liquid crystal element excellent in initial voltage retention and light resistance [Technical Means for Solving Problems]

The inventors of the present invention conducted diligent studies to achieve the above-mentioned problems of the prior art, and found that the 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 is different from the polyorganosiloxane (C) and the polyorganosiloxane (C) At least any one of the polymers contains a partial structure expressing liquid crystallinity in the molecule. <2> A liquid crystal alignment film formed using the liquid crystal alignment agent described in the above <1>. <3> A liquid crystal element including the liquid crystal alignment film described in <2>. <4> A method for manufacturing a liquid crystal alignment film, comprising: applying the liquid crystal alignment agent of <1> on a substrate to form a coating film, and irradiating light on the surface of the substrate coated with the liquid crystal alignment agent To impart the liquid crystal alignment ability to the coating film. <5> A method for manufacturing a liquid crystal element, comprising: forming a liquid crystal alignment film on the respective surfaces of a pair of substrates by the method described in <4>; A step of arranging the pair of substrates with a liquid crystal layer containing a polymerizable monomer to construct a liquid crystal cell; and a step of irradiating the liquid crystal cell with light. <6> A method of manufacturing a liquid crystal element, comprising: using the method of <4> and using a liquid crystal alignment agent containing a polymerizable monomer to form a liquid crystal alignment film on each surface of a pair of substrates; The respective liquid crystal alignment films are opposed to each other, a step of arranging the pair of substrates through a liquid crystal layer to construct a liquid crystal cell; and a step of irradiating the liquid crystal cell with light. [Effects of the invention]

According to the liquid crystal alignment agent of the present disclosure, a liquid crystal element having a high initial voltage retention rate and excellent light resistance can be obtained. In addition, the liquid crystal alignment agent of the present disclosure can be applied to the photo-alignment method to manufacture the liquid crystal alignment film. Therefore, compared with the previous rubbing method, it can suppress the generation of display defects or the decrease in yield caused by the generation of dust or static electricity. This is excellent in terms 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 polyorganosiloxane (C) having a photo-alignment group. In addition, a polymer having a partial structure exhibiting liquid crystallinity is contained as at least any one of polyorganosiloxane (C) and a polymer different from it. The partial structure exhibiting liquid crystallinity may be contained in the polyorganosiloxane (C), may be contained in a polymer different from the polyorganosiloxane (C), or may be contained in the two types of polymers. From the viewpoint of the initial voltage retention rate and light resistance of the liquid crystal element, the partial structure expressing liquid crystallinity is preferably contained in a polymer different from the polyorganosiloxane (C). That is, the liquid crystal alignment agent of the present disclosure preferably contains a polymer (A) that exhibits liquid crystallinity in a predetermined temperature range, and a polyorganosiloxane (C) having a photo-alignment group. Hereinafter, the polymer (A) and the polyorganosiloxane (C) will be described in detail, and other components that are optionally blended into the liquid crystal alignment agent of the present disclosure will be described as needed.

（式（1）中，Ar¹ 及Ar² 分別獨立地為經取代或未經取代的伸苯基或伸環己基，X¹ 為單鍵、-CO-、-COO-、-C＝C-、-C≡C-、-N=N-或-CONR¹ -（R¹ 為氫原子或一價的有機基）。n為1～3的整數。當n為2或3時，Ar² 、X¹ 分別獨立地具有所述定義。“﹡”表示結合鍵）<Polymer (A)> As long as the polymer (A) exhibits liquid crystallinity within a predetermined temperature range, its structure is not particularly limited, and a rigid part (mesogen structure) can be cited as the display Liquid crystal partially structured polymer. As the mesogen structure possessed by the polymer (A), for example, a structure represented by the following formula (1) and the like can be cited. [化1]

(In formula (1), Ar ¹ and Ar ² are each independently substituted or unsubstituted phenylene or cyclohexylene, 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 has the above-mentioned definition independently. "*" means a bond)

（式中，“﹡”表示結合鍵）In the formula (1), X ¹ is preferably a single bond or -COO-. Examples of the monovalent organic group for 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, for example, a tertiary butoxycarbonyl group, a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethoxycarbonyl group, an allyloxycarbonyl group, and the like. 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. As preferred specific examples of the partial structure represented by the formula (1), for example, 4-biphenyl, 4-bicyclohexyl, p-terphenyl, 4,4'-biphenyl, 4 ,4'-Bicyclohexylene, p-terphenylene, and groups represented by the following formulas (1-1) to (1-4), and having a methyl group or a fluorine atom on the ring portion of these groups The base and so on. [化2]

(In the formula, "﹡" means the combination bond)

The polymer (A) may have a mesogen structure on either the main chain or the side chain of the polymer, but from the viewpoint of the high effect of improving the light resistance of the liquid crystal element, it is preferable to have a mesogen structure on the side chain The side chain type liquid crystalline polymer. Here, in this specification, the "main chain" of the polymer refers to the "dry" part of the chain including the longest atom in the polymer. The "dry" part is allowed to contain a ring structure. Therefore, the so-called "has a mesogen structure in the main chain of the polymer" means that the structure constitutes a part of the main chain. The so-called "side chain" of the polymer refers to the part branched from the "stem" of the polymer. Furthermore, the polymer (A) may have a mesogen structure only in the main chain of the polymer, may have a mesogen structure only in the side chain, or may have a mesogen 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 from the viewpoint of affinity with liquid crystals, mechanical strength, etc., it is preferably a polymer selected from a monomer having a polymerizable unsaturated bond (hereinafter, also At least one of the group consisting of “polymer (PAc)”), polyamide, polyimide, and polyamide can make the voltage retention and light resistance of the liquid crystal element 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. Examples include (meth)acrylic compounds, conjugated diene compounds, Aromatic vinyl compounds, maleimide compounds, etc. From the viewpoint that the light resistance improvement effect of the liquid crystal element is high, the polymer (PAc) is preferably a polymer obtained by using a monomer containing a (meth)acrylic compound as a raw material. When synthesizing the polymer (PAc), the use ratio of the (meth)acrylic compound is preferably 50 mol% or more, and more preferably 60 mol% or more with respect to the total amount of monomers used for synthesis. Furthermore, it is more preferable to set it as 70 mol or more. In addition, in this specification, "(meth)acrylic acid" means including acrylic acid and methacrylic acid.

The polymer (PAc) may have a partial structure that exhibits liquid crystallinity, and has a functional group (hereinafter referred to as Fries rearrangement) that induces light to cause crosslinking reaction, isomerization reaction, photodimerization reaction, or Fries rearrangement reaction "Photoreactive group"). As the photoreactive group, for example, a (meth)acrylic acid-containing group having (meth)acrylic acid or its derivative as a basic skeleton, a vinyl group (alkenyl, styryl, etc.), acetylene Group, epoxy group (oxiranyl group, oxetanyl group), group containing phenyl benzoate or its derivative as the basic skeleton, containing azobenzene or its derivative as the basic skeleton The azobenzene-containing group of the skeleton, the cinnamic acid structure-containing group containing cinnamic acid or its derivative as the basic skeleton, the chalcone-containing group containing chalcone or its derivative as the basic skeleton, the benzyl group containing A benzophenone-containing group having a ketone or a derivative thereof as a basic skeleton, a coumarin-containing group having a coumarin or a derivative thereof as a basic skeleton, and the like.

（式（2-1）～式（2-5）中，R² 為氫原子或甲基，R³ 為碳數1～12的烷二基、或利用-O-取代該烷二基的至少1個亞甲基而成的二價的基，R⁴ 為碳數1～20的烷基、烷氧基或氟烷基、或氟原子）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 used preferably contains a compound having a polymerizable unsaturated bond and a partial structure exhibiting liquid crystallinity. As specific examples of the monomer having a polymerizable unsaturated bond and a partial structure expressing liquid crystallinity, for example, compounds represented by the following formulas (2-1) to (2-5) and the like can be cited. In addition, these monomers may be used individually by 1 type, and may be used in combination of 2 or more types. [化3]

(In formulas (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 carbons, or at least one of the alkanediyl groups substituted with -O- A divalent group consisting of a methylene group, R ⁴ is a C 1-20 alkyl group, alkoxy group or fluoroalkyl group, or a fluorine atom)

In addition, when synthesizing a polymer (PAc), a compound that does not have a partial structure that exhibits liquid crystallinity may be used together as a monomer having a polymerizable unsaturated bond. The usage ratio of the compound which does not have a partial structure expressing liquid crystallinity is preferably 50 mol% or less, and more preferably 40 mol% or less with respect to the total amount of 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), Azo compounds such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). The use ratio of the polymerization initiator is preferably 0.01 to 30 parts by mass relative to 100 parts by mass of all monomers used for the reaction. The polymerization is preferably carried out in an organic solvent. Examples of organic solvents used in the reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds. Specific examples include diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether. Acetate, tetrahydrofuran, etc. The reaction temperature is preferably 30°C to 120°C, and the reaction time is preferably 1 hour to 36 hours. The use amount (a) of the organic solvent is preferably set to such an amount that the total amount (b) of the monomers used for the reaction becomes 0.1% by mass to 60% by mass relative to the total amount (a+b) of the reaction solution.

The weight average molecular weight (Mw) of the polymer (PAc) in terms of polystyrene as measured by Gel Permeation Chromatography (GPC) is preferably 250 to 500,000, more preferably 500 to 100,000, and even more preferably 1,000 to 50,000. Furthermore, the polymer (PAc) can be used alone or in combination of two or more.

（式（3）中，R⁵ 為二價的有機基）・Polyamic acid as the polymer (A) polyamic acid (hereinafter also referred to as "polyamic acid (A)") is not particularly limited as long as it exhibits liquid crystallinity, but it can be preferably used Those with a mesogen structure in the main chain of the polymer. When such a polyamide acid is to be obtained, for example, at least any one of a tetracarboxylic dianhydride having a mesogen structure in the main chain and a diamine compound having a mesogen structure in the main chain can be used It is obtained by polymerization of raw materials. As an example of a polyamide acid exhibiting liquid crystallinity, a polymer obtained by reacting a tetracarboxylic dianhydride having a terphenyl skeleton in the main chain with a diamine compound can be cited. Specifically, there can be cited A polymer having a partial structure represented by the following formula (3). [化4]

(In 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 making polyamic acid exhibit liquid crystallinity, R ⁵ is preferably a linear alkanediyl group having 4 to 20 carbon atoms, or a divalent group containing -O- between the carbon-carbon bonds of the alkanediyl group.的基。 The base.

The tetracarboxylic dianhydride used for the synthesis of the polyamide acid (A) may be only tetracarboxylic dianhydride having a mesogen structure, but tetracarboxylic dianhydride not having a mesogen structure may be used in combination. The said tetracarboxylic dianhydride is not specifically limited, A well-known tetracarboxylic dianhydride can be used. When synthesizing polyamide acid exhibiting liquid crystallinity, the use ratio of tetracarboxylic dianhydride having a mesogen structure is preferably 50 mol% or more with respect to the total amount of tetracarboxylic dianhydride used for synthesis. More preferably, it is set to 70 mol% or more.

As a diamine compound used for the synthesis of polyamide acid (A), aliphatic diamine, alicyclic diamine, aromatic diamine, diamino organosiloxane etc. are mentioned, for example. Among these, aliphatic diamines can be preferably used, and alkylene diamines such as 1,4-diaminobutane, hexamethylene diamine, and octamethylene diamine are more preferable. When synthesizing polyamide acid (A), relative to the total amount of the diamine compound used in the synthesis, the use ratio of alkylene diamine is preferably 50 mol% or more, more preferably 60 mol% or more .

The polyamide acid (A) can be obtained by reacting the above-mentioned tetracarboxylic dianhydride and diamine compound with a molecular weight modifier as necessary. The use ratio of the tetracarboxylic dianhydride to the diamine compound used in the synthesis reaction of the polyamide acid is preferably a ratio of 0.2 to 2 equivalents of the acid anhydride group of the tetracarboxylic dianhydride with respect to 1 equivalent of the amino group of the diamine compound. Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride and phthalic anhydride, monoamine compounds such as aniline, cyclohexylamine, and n-butylamine, phenyl isocyanate, and naphthalene isocyanate. Monoisocyanate compounds such as esters. The use ratio of the molecular weight modifier is preferably set to 20 parts by mass or less with respect to the total of 100 parts by mass of the tetracarboxylic dianhydride and the diamine compound.

The synthesis reaction of polyamide 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 aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Particularly preferred organic solvents are preferably selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfene, γ-butyrolactone One or more of the group consisting of ester, tetramethylurea, hexamethylphosphotriamine, m-cresol, xylenol, and halogenated phenol are used as a solvent, or one or more of these organic solvents can be used with other organic solvents (For example, butyl cellosolve, diethylene glycol diethyl ether, etc.) mixture. The use amount (a) of the organic solvent is preferably such that the total amount (b) of the tetracarboxylic dianhydride and the diamine becomes 0.1% by mass to 50% by mass relative to the total amount (a+b) of the reaction solution. In this manner, a reaction solution obtained by dissolving polyamide acid (A) can be obtained. The reaction solution may be directly used for the preparation of the liquid crystal alignment agent, or may be used for the preparation of the liquid crystal alignment agent after isolating the polyamide acid contained in the reaction solution.

・Polyurate as the polymer (A), for example, can be obtained by the following method: the polyamide (A) obtained by the synthesis reaction and the esterification agent ( For example, alcohols, etc.) method of reaction; method of reacting tetracarboxylic acid diester and diamine compound; method of reacting tetracarboxylic acid diester dihalide and diamine compound. The obtained polyamide ester may have only an amide acid ester structure, or may be a partial ester product in which an amide acid structure and an amide acid ester structure coexist. Furthermore, the reaction solution obtained by dissolving the polyamide ester may be directly used for the preparation of the liquid crystal alignment agent, or may be used for the preparation of the liquid crystal alignment agent after isolating the polyamide ester contained in the reaction solution.

・Polyimine Polyimine as the polymer (A) can be obtained, for example, by dehydrating and ring-closing the polyimide (A) synthesized in the manner described above and then imidizing it. Polyimide may be a complete amide compound formed by dehydrating and ring-closing all the amide acid structure of the polyamide acid as its precursor, or it may be dehydrated only a part of the amide acid structure A partial amide compound in which the ring is closed and the amide structure and amide ring structure coexist. The imidization rate of the polyimide used for the reaction is preferably 20% to 99%, more preferably 30% to 90%. The imidization rate is expressed as a percentage of the ratio of the number of amide ring structures to the sum of the number of amide acid structures of polyimide and the number of amide ring structures.

The dehydration ring-closure of polyamide acid is performed by, for example, the following method: dissolving polyamide acid in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, and heating if necessary. As the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 0.01 mol to 20 mol relative to 1 mol of the amide acid structure of the polyamide acid. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. The amount of the dehydration ring-closing catalyst used is preferably 0.01 mol to 10 mol relative to 1 mol of the dehydrating agent used. As the organic solvent used in the dehydration ring-closure reaction, the organic solvent exemplified as the organic solvent used in the synthesis of polyamide acid can be cited. The reaction temperature of the dehydration ring-closing reaction is preferably 0°C to 180°C. The reaction time is preferably 1.0 hour to 120 hours. In this way, a reaction solution containing polyimine can be obtained. The reaction solution can be directly used for the preparation of the liquid crystal alignment agent, or can be used for the preparation of the liquid crystal alignment agent after the polyimide is isolated.

When a solution with a concentration of 10% by mass is made, the solution viscosity of polyamide acid, polyamide ester, and polyimide as the polymer (A) is preferably a solution with a viscosity of 10 mPa·s to 800 mPa·s The viscosity is more preferably a solution viscosity of 15 mPa·s to 500 mPa·s. Furthermore, the solution viscosity (mPa·s) is for a polymer solution with a concentration of 10% by mass prepared using a good solvent for these polymers (such as γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) , The value measured at 25°C using an E-type rotary viscometer. The weight average molecular weight (Mw) in terms of polystyrene measured by GPC of the polyamide acid, polyamide ester, and polyimide is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000. In addition, the molecular weight distribution (Mw/Mn) represented by the ratio of Mw and the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 15 or less, and 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 from the viewpoint of sufficiently improving the alignment control power and alignment stability of the obtained liquid crystal alignment film In other words, the liquid crystal temperature range is preferably in the range of 90°C to 380°C, more preferably in the range of 100°C to 350°C.

（式（cn-1）中，R¹¹ 為氫原子、鹵素原子、碳數1～3的烷基、碳數1～3的烷氧基或氰基。R¹² 為伸苯基、伸聯苯基、伸三聯苯基或伸環己基，或這些基所具有的氫原子的至少一部分經鹵素原子、碳數1～10的烷基、碳數1～10的烷氧基或氰基取代的基。A¹¹ 為單鍵、氧原子、硫原子、碳數1～3的烷二基、-CH=CH-、-NH-、﹡¹ -COO-、﹡¹ -OCO-、﹡¹ -NH-CO-、﹡¹ -CO-NH-、﹡¹ -CH₂ -O-或﹡¹ -O-CH₂ -（“﹡¹ ”表示與R¹² 的結合鍵）。R¹³ 為鹵素原子、碳數1～3的烷基、碳數1～3的烷氧基或氰基。a為0或1，b為0～4的整數。其中，當b為2以上時，多個R¹³ 可相同，也可以不同。“﹡”表示結合鍵） [化6]

（式（cn-2）中，R¹⁴ 為碳數1～20的一價的有機基。R¹⁵ 為鹵素原子、碳數1～3的烷基、碳數1～3的烷氧基或氰基。A¹² 為氧原子、﹡¹ -COO-、﹡¹ -OCO-、﹡¹ -NH-CO-或﹡¹ -CO-NH-（“﹡¹ ”表示與R¹⁶ 的結合鍵）。R¹⁶ 為碳數1～6的烷二基。c為0或1，d為0～4的整數。其中，當d為2以上時，多個R¹⁵ 可相同，也可以不同。“﹡”表示結合鍵）<Polyorganosiloxane (C)> The photo-alignment group of polyorganosiloxane (C) uses photoisomerization reaction, photodimerization reaction or photolysis reaction caused by light irradiation to film Give anisotropic functional groups. The polyorganosiloxane (C) may have a photoalignment group on either the main chain or the side chain, but one having a photoalignment group on the side chain can be preferably used. Specific examples of the photoalignment group possessed by polyorganosiloxane (C) include: the azobenzene-containing group, the cinnamic acid structure-containing group, the chalcone-containing group, and the diphenyl group The base of ketone, the base containing coumarin, etc. Among these, it is preferable to contain the group of a cinnamic acid structure from a viewpoint of high photosensitivity and a viewpoint of easy introduction into a side chain. Among them, the cinnamic acid structure-containing group of the polyorganosiloxane (C) is preferably selected from groups represented by the following formula (cn-1) and groups represented by the following formula (cn-2) At least one of the group of. [化5]

(In formula (cn-1), R ¹¹ is a hydrogen atom, a halogen atom, an alkyl group with 1 to 3 carbons, an alkoxy group with 1 to 3 carbons, or a cyano group. R ¹² is a phenylene group, a biphenylene group Group, terphenylene or cyclohexylene, or a group in which at least part of the hydrogen atoms of these groups is substituted with a halogen atom, an alkyl group having 1 to 10 carbons, an alkoxy group having 1 to 10 carbons, or a cyano group 。A ¹¹ is a single bond, oxygen atom, sulfur atom, alkanediyl group with 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 the bond with R ¹² ). R ¹³ is a halogen atom, carbon number An alkyl group having 1 to 3, an alkoxy group having 1 to 3 carbons or a cyano group. a is 0 or 1, and b is an integer of 0 to 4. However, when b is 2 or more, multiple R ¹³ may be the same, It can also be different. "﹡" means a bond) [化6]

(In formula (cn-2), R ¹⁴ is a monovalent organic group having 1 to 20 carbons. R ¹⁵ is a halogen atom, an alkyl group having 1 to 3 carbons, an alkoxy group having 1 to 3 carbons, or a cyano group. A ¹² is an oxygen atom, * ¹ -COO-, * ¹ -OCO-, * ¹ -NH-CO- or * ¹ -CO-NH- ("* ¹ " represents the bond with R ¹⁶ ). R ¹⁶ is an alkanediyl group having 1 to 6 carbon atoms. c is 0 or 1, and d is an integer of 0 to 4. However, when d is 2 or more, multiple R ¹⁵ may be the same or different. "*" means Combination key)

Examples of the monovalent organic group for R ¹⁴ include alkyl groups 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 cyclohexylene, R ²² is substituted or unsubstituted phenyl or cyclohexyl, X ² is a single bond, oxygen atom, sulfur atom, alkanediyl group with 1 to 3 carbons, -CH=CH-,- NH-, -COO-, -NH-CO- or -CH ₂ -O-) etc. Examples of the substituent of R ²¹ and R ²² include a halogen atom, an alkyl group having 1 to 3 carbons, an alkoxy group having 1 to 3 carbons, and a cyano group.

The method of synthesizing polyorganosiloxane (C) is not particularly limited. As an example, a method of hydrolyzing and condensing an epoxy-containing hydrolyzable silane compound and other silane compounds as necessary, and then reacting a carboxylic acid having a photoalignment group. As an epoxy group-containing silane compound, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyl Triethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc. Other silane compounds are not particularly limited as long as they are hydrolyzable compounds. Examples include tetramethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, and p-styryltrimethoxysilane. Silane, vinyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, trimethoxysilane Base silyl propyl succinic anhydride, etc. In addition, the silane compound may be used alone or in combination of two or more.

The hydrolysis/condensation reaction is carried out by reacting one or two or more silane compounds with water, preferably in the presence of a suitable catalyst and organic solvent. During the reaction, the use ratio of water is preferably 1 mol to 30 mol relative to 1 mol of the silane compound (total amount). Examples of the catalyst used include acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds, and the like. The amount of the catalyst used varies depending on the type of the catalyst, reaction conditions such as temperature, and the like. For example, it is 0.01 times mol to 3 times mol relative to the total amount of the silane compound. As the organic solvent to be used, for example, hydrocarbons, ketones, esters, ethers, alcohols, etc. are mentioned, and it is preferable to use a water-insoluble or poorly water-soluble organic solvent. The use ratio of the organic solvent is preferably 10 parts by mass to 10,000 parts by mass relative to the total 100 parts by mass of the silane compound used for the reaction. In addition, the reaction is preferably carried out by heating with an oil bath or the like. At this time, the heating temperature is preferably 130°C or lower, and the heating time is preferably 0.5 hour to 12 hours. After the reaction is completed, the organic solvent layer separated from the reaction solution is dried with a desiccant as needed, and then the solvent is removed, thereby obtaining an epoxy group-containing polyorganosiloxane.

The reaction of the epoxy-containing polyorganosiloxane and carboxylic acid is preferably carried out in the presence of a catalyst and an organic solvent. The use ratio of the carboxylic acid is preferably 5 mol% or more, and more preferably 10 mol% to 80 mol% relative to the epoxy group of the epoxy group-containing polyorganosiloxane. As the catalyst, for example, an organic base, a compound known as a so-called hardening accelerator that promotes the reaction of an epoxy compound, and the like can be used. The use ratio of the catalyst is preferably 100 parts by weight or less with respect to 100 parts by weight of epoxy group-containing polysiloxane. Preferable specific examples of the organic solvent used include 2-butanone, 2-hexanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and butyl acetate. The organic solvent is preferably used at a ratio such that the solid content concentration becomes 5 wt% to 50 wt%. 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 the reaction is completed, the organic solvent layer separated from the reaction solution is dried with a desiccant as needed, and the solvent is removed, thereby obtaining a polyorganosiloxane (C) having a photo-alignment group. In addition, the synthesis method of polyorganosiloxane (C) is not limited to the above-mentioned hydrolysis/condensation reaction. For example, it may be carried out by a method of reacting a hydrolyzable silane compound in the presence of oxalic acid and alcohol. In addition, when a polyorganosiloxane having a photoalignment group on the side chain is to be obtained, a method of using a hydrolyzable silane compound having a photoalignment group for the polymerization of the raw material can also be adopted.

For the polyorganosiloxane (C), the weight average molecular weight in terms of polystyrene measured by GPC is preferably 500 to 1,000,000, more preferably 1,000 to 100,000, and still more preferably 1,000 to 50,000. Furthermore, the polyorganosiloxane (C) may be used singly or in combination of two or more.

The liquid crystal alignment agent of the present disclosure preferably contains at least one polymer selected from the group consisting of polyamide acid, polyamide acid ester, and polyimide in the polymer component. The polymer may be a polymer (A) exhibiting liquid crystallinity in a predetermined temperature range, or a polymer not exhibiting liquid crystallinity. The preferred form of the liquid crystal alignment agent of the present disclosure further contains at least one selected from the group consisting of polyamide acid, polyamide acid ester and polyimide, and is a non-liquid crystal polymer ( Hereinafter, it is also referred to as "polymer (B)") as a polymer component. By containing such a polymer (B), it is suitable from the viewpoint that the initial voltage retention rate of the liquid crystal element and the improvement effect of light resistance can be improved.

The polyamide (hereinafter also referred to as "polyamide (B)") as the polymer (B) can be obtained, for example, by reacting tetracarboxylic dianhydride and a diamine compound. As specific examples of the tetracarboxylic dianhydride used in the synthesis of polyamide acid, examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and ethylenediamine Tetraacetic dianhydride, etc.; as alicyclic tetracarboxylic dianhydride, for example, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic 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-furyl)-3-methyl-3-cyclohexene -1,2-Dicarboxylic anhydride, 2,4,6,8-tetracarboxylic bicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclohexanetetracarboxylic dianhydride, etc.; as Aromatic tetracarboxylic dianhydride, for example, pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, p-phenylene bis(trimellitic acid monoester) Anhydride), ethylene glycol bis(dehydrated trimellitate), 1,3-propanediol bis(dehydrated trimellitate), etc.; otherwise, the description in Japanese Patent Laid-Open No. 2010-97188 can be used的tetracarboxylic dianhydride. Furthermore, tetracarboxylic dianhydride can be used individually by 1 type or in combination of 2 or more types.

As specific examples of the diamine compound used in the synthesis of polyamide acid (B), examples of the aliphatic diamine include metaxylylenediamine, 1,3-propanediamine, hexamethylenediamine, etc. ; As alicyclic diamines, for example, 1,4-diaminocyclohexane, 4,4'-methylene bis(cyclohexylamine), etc.; as aromatic diamines, for example, dodecyloxy Diaminobenzene, octadecyloxydiaminobenzene, cholesteryloxydiaminobenzene, cholesteryloxydiaminobenzene, cholesteryl diaminobenzoate, cholesteryl diaminobenzoate Esters, lanosteryl diaminobenzoate, 3,6-bis(4-aminobenzyloxy)cholestane, 1,1-bis(4-((aminophenyl)methyl)phenyl ) Side-chain type diamines such as 4-butylcyclohexane, 2,5-diamino-N,N-diallylaniline, and the compound represented by the following formula (E-1):

(In formula (E-1), X ^I and X ^II are each independently a single bond, -O-, -COO- or -OCO-, R ^I is an alkanediyl group with 1 to 3 carbon atoms, and R ^II is a single bond Bond or alkanediyl group with 1 to 3 carbon atoms, a is 0 or 1, b is an integer of 0 to 2 (wherein a and b are not changed to 0 at the same time), c is an integer of 1 to 20, and d is 0 or 1 .)

P-phenylenediamine, 4,4'-diaminodiphenylmethane, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 1,5-bis(4 -Aminophenoxy)pentane, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, N,N-bis(4-aminophenyl)methylamine, 2,6-diamino Pyridine, 1,4-bis-(4-aminophenyl)-piperazine, 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-bis [4-(4-Aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(phenylene diisopropylidene) bisaniline, 4-(4-Aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1, 4-Diyl)] diphenylamine, diamine containing cinnamic acid structure and other main chain diamines; as diaminoorganosiloxanes, for example, 1,3-bis(3-aminopropyl)-tetramethyl Disiloxane, etc.; in addition, the diamine described in JP 2010-97188 A can be used. Furthermore, the diamine compound can be used individually by 1 type or in combination of 2 or more types.

The polyamide acid (B) can be obtained by reacting the above-mentioned tetracarboxylic dianhydride and diamine compound with a molecular weight modifier as necessary. Regarding the molecular weight modifier, polymerization solvent, reaction conditions, etc. used in this reaction, the description of polyamide acid (A) can be applied. As the polymer (B), the polyamide and polyimide can be the same as the case of the polymer (A), except that polyamide (B) is used instead of polyamide (A). Way to get. Regarding the solution viscosity, weight average molecular weight and number average molecular weight of the polymer (B), the description of the polymer (A) applies.

The polymer component in the liquid crystal alignment agent of this disclosure is preferably any one of the following [1] to [4]. [1] Containing polymer (A) and polyorganosiloxane (C) as polymer components, and polymer (A) is in the form of polymer (PAc). [2] Contains polymer (A) and polyorganosiloxane (C) as polymer components, and polymer (A) is selected from polyamide acid, polyamide ester and polyimide At least one form of the group. [3] Containing polymer (A), polymer (B), and polyorganosiloxane (C) as polymer components, and polymer (A) is in the form of polymer (PAc). [4] Containing polymer (A), polymer (B) and polyorganosiloxane (C) as polymer components, and polymer (A) is selected from the group consisting of polyamide acid, polyamide ester and poly The form of at least one of the group consisting of imines. Among these aspects, [1] and [3] are more preferable from the viewpoint of the initial voltage retention rate and light resistance of the liquid crystal element, and [3] is particularly preferable. In addition, the polymer (A) and the polymer (B) may be those exhibiting photosensitivity to the exposure used to make the polyorganosiloxane (C) anisotropically induced by light, or they may be The exposure is non-photosensitive. From the viewpoint of the initial voltage retention rate and light resistance of the liquid crystal element, non-photosensitive is preferable.

In the liquid crystal alignment agent of the present disclosure, the content ratio of the polymer (A) and the polyorganosiloxane (C) is relative to the viewpoint that the initial voltage retention rate and the light resistance improvement effect of the liquid crystal element can be sufficiently obtained The total amount of the polymer components contained in the liquid crystal alignment agent is 100 parts by mass. 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, and still more preferably 5 parts by mass. Parts by mass ~ 60 parts by mass. The polyorganosiloxane (C) is preferably 1 part by mass to 99 parts by mass, more preferably 5 parts by mass to 95 parts by mass, with respect to 100 parts by mass of the total polymer components contained in the liquid crystal alignment agent. More preferably, it is 10 mass parts-90 mass parts. In addition, the ratio of polymer (A) to polyorganosiloxane (C) is calculated by mass ratio, and is preferably set to polymer (A): polyorganosiloxane (C) = 5:95 to 70:30, more 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 disclosure, the content ratio of the polymer (B) is preferably set to 1 part by mass relative to 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, and still more preferably 40 parts by mass to 80 parts by mass.

The liquid crystal alignment agent of the present disclosure may contain other components other than the polymer (A) and polyorganosiloxane (C), and the polymer (A) and polyorganosiloxane (C). As other components, in addition to the polymer (B), for example, other polymers other than the polymer (A), the polymer (B), and polyorganosiloxane (C), which have at least one epoxy group in the molecule Compounds, functional silane compounds, antioxidants, metal chelating compounds, hardening accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The blending ratio of other components can be appropriately selected corresponding to each compound within a range that does not impair the effects of the present disclosure.

(Solvent) The liquid crystal alignment agent of the present disclosure is preferably prepared as a liquid composition in which a polymer component and other components used as needed are dispersed or dissolved in an appropriate solvent. As the organic solvent used, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolinone, γ-butyrolactone, γ -Butyrolactamide, 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, diethylene two 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, etc. These organic solvents can 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 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 1 mass is preferred %～10% by mass. That is, the liquid crystal alignment agent is coated on the surface of the substrate as described later, and it is preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that is 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 good 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 good liquid crystal alignment film. In addition, the viscosity of the liquid crystal alignment agent tends to increase and coatability decreases.

<Liquid crystal element> The liquid crystal element of this disclosure 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. For example, it can be applied to twisted nematic (TN) type, super twisted nematic (STN) type, and vertical alignment type (including vertical alignment (Vertical)). Alignment, VA)-Multi-Domain Vertical Alignment (MVA) type, VA-Patterned Vertical Alignment (PVA) type, etc.), 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 manufactured by a method including the following steps 1 to 3, for example. In step 1, the substrate used varies according to the desired operation mode. Steps 2 and 3 are shared by all operation modes.

[Step 1: Formation of Coating Film] First, the liquid crystal alignment agent is coated on the substrate, and then, if necessary, the coated surface is heated, thereby forming a coating film on the substrate. As the substrate, for example, glass such as float glass, soda glass, etc. can be used; including polyethylene terephthalate, polybutylene terephthalate, polyether alkene, polycarbonate, and poly(alicyclic olefin) Such as plastic transparent substrate. As the transparent conductive film provided on one side of the substrate, NESA film (registered trademark of PPG Corporation, USA) containing tin oxide (SnO ₂ ), oxide containing indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) can be used Indium Tin Oxide (ITO) film, etc. When manufacturing TN type, STN type or vertical alignment type liquid crystal elements, two substrates provided with patterned transparent conductive films are used. When manufacturing a liquid crystal element of a transverse electric field type such as an IPS type or an FFS type, a substrate provided with electrodes including a transparent conductive film or a metal film patterned in a comb-like shape and a counter substrate without electrodes are used. As the metal film, for example, a film containing metal such as chromium can be used. The coating on the substrate is on the electrode formation surface, and is preferably performed 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 sagging of the applied liquid crystal alignment agent, etc., it is preferable to perform preheating (prebaking). The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. After that, the solvent is completely removed, and if necessary, a sintering (post-baking) step is performed for the purpose of thermally imidizing the amide structure existing in the polymer. The firing temperature (post-baking temperature) at this time is preferably 80°C to 300°C, and the post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the film formed in this manner is preferably 0.001 μm to 1 μm.

[Step 2: Alignment Treatment] When manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal element, a treatment (alignment treatment) for imparting liquid crystal alignment ability to the coating film formed in the 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. As the alignment treatment, for example, a rubbing treatment in which a cloth containing nylon, rayon, cotton and other fibers is wound, rubs the coating film in a fixed direction, thereby imparting liquid crystal alignment ability to the coating film; The surface of the substrate coated with the liquid crystal alignment agent is irradiated with light to impart the liquid crystal alignment ability to the coating film by photo alignment treatment or the like. From the viewpoint of imparting sufficient liquid crystal alignment control power by light irradiation to the coating film, or suppressing the generation of display defects or the decrease in yield caused by the generation of dust or static electricity, it can be used to form a substrate From the viewpoint that the above organic film uniformly imparts the alignment ability to the liquid crystal, the liquid crystal alignment agent of the present disclosure can preferably be applied with a photo-alignment treatment. When manufacturing a vertical alignment type liquid crystal element, the coating film formed in step 1 can be directly used as a liquid crystal alignment film, but the coating film can also be subjected to alignment treatment.

In the photo-alignment process, the light for irradiating the coating film can use, for example, ultraviolet rays and visible rays including light with a wavelength of 150 nm to 800 nm. It is preferable to include ultraviolet light having a wavelength of 200 nm to 400 nm. When the irradiated light is linearly polarized light or partially polarized light, the substrate surface may be irradiated from a vertical direction, the substrate surface may be irradiated from an oblique direction, or both may be combined. When irradiating non-polarized radiation, the direction of irradiation is set as an oblique direction. As the light source used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. Ultraviolet rays in the preferred wavelength range can be obtained by a method of using a light source in combination with, for example, an optical filter and a diffraction grating. The radiation dose 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 can be irradiated with light for imparting alignment ability, or the coating film after the pre-baking step and before the post-baking step can be irradiated with light for imparting alignment ability, or In at least any one of the pre-baking step and the post-baking step, the coating film is irradiated with light for imparting alignment ability during the heating process.

[Step 3: Construction of a liquid crystal cell] Two substrates on which a liquid crystal alignment film is formed in the manner described above are prepared, and liquid crystals are arranged between the two substrates arranged opposite to each other, thereby manufacturing a liquid crystal cell. Specifically, a method of bonding the peripheral parts of the pair of substrates with a sealant, injecting and filling liquid crystal into the cell gap defined by the substrate surface and the sealant, and sealing the injection hole; Coated on the peripheral part of the liquid crystal alignment film side of one substrate, and then drop the liquid crystal on the predetermined spots on the liquid crystal alignment film surface, then bond the other substrate so that the liquid crystal alignment film faces the other substrate, and squeeze the liquid crystal A method (One Drop Fill (ODF) method) in which the pressure spreads over the entire surface of the substrate and then hardens the sealant. As the sealing agent, for example, an epoxy resin containing a curing agent and alumina balls as a spacer, etc. may be mentioned. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferred. Examples include schiff base liquid crystals, azoxy liquid crystals, and biphenyl liquid crystals. , Phenylcyclohexane-based liquid crystal, ester-based liquid crystal, terphenyl-based liquid crystal, biphenylcyclohexane-based liquid crystal, pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal, cubaane-based liquid crystal, etc. In addition, cholesteric liquid crystals, chiral reagents, ferroelectric liquid crystals, etc. can be added to these liquid crystals for use.

In step 3, the following treatments can be performed: construct a liquid crystal cell containing a polymerizable monomer in the liquid crystal layer, and irradiate the constructed liquid crystal cell with light to polymerize the polymerizable monomer to give the initial stage of the liquid crystal Alignment. By performing this treatment, when applied to a transverse electric field type such as an IPS type or an FFS type, it is suitable in terms of obtaining a liquid crystal element having a high initial voltage retention rate and excellent light resistance.

As the polymerizable monomer, from the viewpoint of high polymerizability by light, a compound having two or more (meth)acryloyl groups can be preferably used. Specific examples thereof include, for example, di(meth)acrylate having a biphenyl structure, di(meth)acrylate having a phenyl-cyclohexyl structure, and di(meth)acrylate having a 2,2-diphenylpropane structure. (Meth) acrylate, di(meth)acrylate with diphenylmethane structure, di-thio(meth)acrylate with diphenyl sulfide structure, di(meth)acrylic acid with naphthalene structure Ester, di(meth)acrylate having an anthracene structure, di(meth)acrylate having a phenanthrene structure, di(meth)acrylate having a structure that generates radicals by light irradiation, and the like. The blending ratio of the polymerizable monomer is preferably 0.1% by mass to 1.0% by mass relative to the total amount of the liquid crystal composition used for the formation of the liquid crystal layer. In addition, a polymerizable monomer may be used individually by 1 type, and may be used in combination of 2 or more types.

The light irradiation to the liquid crystal cell can be performed in a state where no voltage is applied between a pair of electrodes, or in a state where a predetermined voltage (for example, 0 V) at which the liquid crystal molecules in the liquid crystal layer are not driven is applied, or it can be performed It is performed in a state where a predetermined voltage driven by the liquid crystal molecules is applied. When the liquid crystal alignment agent of the present disclosure is applied to a liquid crystal element including a liquid crystal cell of a lateral electric field type, it is preferable to irradiate the liquid crystal cell with light in a state where no voltage is applied between a pair of electrodes. As the light to be irradiated, for example, ultraviolet rays and visible rays including light with a wavelength of 150 nm to 800 nm can be used, and ultraviolet rays including light with a wavelength of 300 nm to 400 nm are preferable. When the radiation used is linearly polarized or partially polarized, the light irradiation direction can be irradiated from the vertical direction to the substrate surface, or from the oblique direction to the substrate surface, or a combination of the two get on. When irradiating non-polarized radiation, the irradiation direction is set to an oblique direction.

As a light source for irradiating light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. Furthermore. The ultraviolet rays in the preferred wavelength range can be obtained by a method of using a light source together with, for example, an optical filter, a diffraction grating, or the like. The amount of light irradiation 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 .

It is also possible to first mix the polymerizable monomer into the liquid crystal alignment film instead of mixing the polymerizable monomer into the liquid crystal layer, and irradiate the liquid crystal cell with light, thereby imparting initial alignment to the liquid crystal. In this case, in step 1, a liquid crystal alignment agent containing a polymerizable monomer is used to form a coating film on the substrate. As the polymerizable monomer contained in the liquid crystal alignment agent, the description of the polymerizable monomer contained in the liquid crystal layer is applied. The content ratio of the polymerizable monomer is preferably 1 part by mass to 100 parts by mass, and more preferably 5 parts by mass to 50 parts by mass relative to 100 parts by mass of the total polymer components contained in the liquid crystal alignment agent.

Then, if necessary, a polarizing plate is bonded to the outer surface of the liquid crystal cell to obtain a liquid crystal element. Examples of the polarizing plate include a polarizing plate formed by sandwiching a polarizing film called "H film" with a protective film of cellulose acetate, or a polarizing plate including the H film itself. The "H film" is made of polyethylene on one side. Alcohol is formed by absorbing iodine on one side of extending alignment.

The liquid crystal element of the present disclosure can be effectively applied to various purposes, such as clocks, portable game consoles, word processors, notebook personal computers, car navigation systems, camcorders, and personal digital assistants (Personal Digital Assistant, PDA), digital cameras, mobile phones, smart phones, various monitors, LCD TVs, information displays and other display devices, or dimming films. In addition, the liquid crystal element formed using the liquid crystal alignment agent of the present disclosure can also be applied to a retardation film. [Example]

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

In the following examples, the weight average molecular weight Mw and epoxy equivalent of the polymer are measured by the following method. [The weight average molecular weight Mw of the polymer]: Based on the results measured by gel permeation chromatography under the following conditions using the following equipment, monodisperse polystyrene is used as a standard substance as a polystyrene conversion value Come find out. Measuring device: manufactured by Tosoh (Stock), model "8120-GPC" Column: manufactured by Tosoh (Stock), "TSKgelGRCXLII" Solvent: Tetrahydrofuran Sample concentration: 5 wt% Sample injection volume: 100 μL tube Column temperature: 40°C Column pressure: 68 kgf/cm ² [Epoxy equivalent]: Measured in accordance with the "hydrochloric acid-methyl ethyl ketone method" of JIS C2105.

[合成例2] 除使用由下述式（m-2）所表示的化合物來代替由所述式（m-1）所表示的化合物以外，藉由與所述合成例1相同的操作來獲得聚合體（A-2）。該聚合體（A-2）在108℃～313℃的溫度範圍內顯示出液晶性。 [化9]

[合成例3] 使1,8-二氨基辛烷0.7009 g（4.858 mmol）溶解在N-甲基-2-吡咯烷酮（NMP）22.5 g中，並在室溫下添加由下述式（m-3）所表示的化合物1.7991 g（4.858 mmol）。在60℃下攪拌2小時後，冷卻至室溫，而獲得含有聚合體（A-3）的溶液。將所獲得的聚合體溶液注入至十分過剩的甲醇中，而使反應產物沉澱。利用甲醇對該沉澱物進行清洗，並在減壓下以40℃乾燥15小時，由此獲得聚合體（A-3）。該聚合體（A-3）在100℃～235℃的溫度範圍內顯示出液晶性。 [化10]

<Synthesis of Polymer (A)> [Synthesis Example 1] The compound represented by the following formula (m-1) was dissolved in tetrahydrofuran, and azobisisobutyronitrile was added as a polymerization initiator to perform polymerization. Thus, a solution containing polymer (A-1) was obtained. With respect to the obtained polymer solution, the solvent in the system was replaced with N-Methyl-2-pyrrolidone (NMP) to obtain a polymer (A-1). This polymer (A-1) showed liquid crystallinity in a temperature range of 116°C to 315°C. [化8]

[Synthesis Example 2] It was obtained by the same operation as in Synthesis Example 1 except that the compound represented by the following formula (m-2) was used instead of the compound represented by the formula (m-1) Polymer (A-2). This polymer (A-2) showed liquid crystallinity in a temperature range of 108°C to 313°C. [化9]

[Synthesis Example 3] 0.7009 g (4.858 mmol) of 1,8-diaminooctane was dissolved in 22.5 g of N-methyl-2-pyrrolidone (NMP), and added at room temperature by the following formula (m- 3) 1.7991 g (4.858 mmol) of the compound represented. After stirring for 2 hours at 60°C, it was cooled to room temperature to obtain a solution containing a polymer (A-3). The obtained polymer solution was poured into a sufficiently excessive amount of methanol to precipitate the reaction product. This deposit was washed with methanol and dried at 40° C. for 15 hours under reduced pressure, thereby obtaining a polymer (A-3). This polymer (A-3) shows liquid crystallinity in a temperature range of 100°C to 235°C. [化10]

<Synthesis of polyorganosiloxane (C)> [Synthesis example 4] Add 2-(3,4-epoxycyclohexyl)ethyltrimethyl to a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux cooling tube 100.0 g of oxysilane, 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine were mixed at room temperature. Then, 100 g of deionized water was dropped from the dropping funnel over 30 minutes, mixed under reflux, and reacted at 80°C for 6 hours. After the reaction, the organic layer was taken out and washed with a 0.2% by mass ammonium nitrate aqueous solution until the washed water became neutral, and then the solvent and water were distilled off under reduced pressure to form a viscous transparent liquid Obtained as a polymer (EPS-1) of epoxy-containing polyorganosiloxane. The polymer (EPS-1) was analyzed by ¹ H-NMR, and as a result, a peak based on an oxirane group was obtained at a chemical shift (δ)=3.2 ppm as the theoretical strength. It was confirmed that no epoxy group was generated during the reaction. The side reaction. The weight average molecular weight of the polymer (EPS-1) is 2,200, and the epoxy equivalent is 186 g/mol. Then, 9.3 g of the polymer (EPS-1) obtained above, 26 g of methyl isobutyl ketone, 3.0 g of the compound represented by the following formula (m-4), and 0.10 g of the trade name "UCAT 18X" (quaternary amine salt manufactured by San-Apro) was reacted at 80°C for 12 hours under stirring. After the reaction, the reaction mixture was poured into methanol and the resulting precipitate was recovered and dissolved in ethyl acetate to prepare a solution. After washing the solution three times with water, the solvent was distilled off to give a white In the form of powder, 6.3 g of polymer (C-1) as polyorganosiloxane (C) was obtained. The weight average molecular weight Mw of this polymer (C-1) was 3,500. [化11]

<Other components> [Synthesis example 5] 100 mole parts of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 4,4'-diamino as diamine 100 mole parts of diphenyl ether was dissolved in NMP and reacted at 40° C. for 3 hours, thereby obtaining a solution containing 10% by mass of the polymer (B-1) as polyamide acid. [Synthesis Example 6] 100 mole parts of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, and 4-aminophenyl-4'-amino as diamine 100 mole parts of nitrobenzene was dissolved in NMP, and reacted at 40° C. for 3 hours, thereby obtaining a solution containing 10% by mass of the polymer (B-2) as a polyamide acid. [Synthesis Example 7] The polymer (D-1) was obtained by the same operation as in Synthesis Example 1 except that octyl methacrylate was used instead of the compound represented by the 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 as the polymer (A) and the polymer (B) The solution containing the polymer (B-1) obtained in Synthesis Example 5 is converted into an amount equivalent to 60 parts by mass of the polymer (B-1), and the above-mentioned synthesis example as polyorganosiloxane (C) 20 parts by mass of the polymer (C-1) obtained in 4 were mixed, and N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (Butyl Cellosolve, BC) were added to it, and the solvent composition was NMP : BC=50:50 (mass ratio), a solution with a solid content concentration of 4.0% by mass. The solution was filtered with a filter with a pore diameter of 1 μm, thereby preparing a liquid crystal alignment agent. (2) Manufacture of liquid crystal display element Two glass substrates with transparent electrodes containing ITO films were prepared, and the liquid crystal alignment agent prepared in (1) was coated on the respective transparent electrode surfaces using a spin coater. Then, after pre-baking on a hot plate at 80°C for 1 minute, in an oven that replaced the interior with nitrogen, heating (post-baking) at 230°C for 30 minutes to form a coating with a thickness of 0.1 μm membrane. Then, using Hg-Xe lamp and Glan-Taylor prism, the respective coating film surface was irradiated with 313 nm bright line polarized ultraviolet light 500 mJ/cm ² from the normal direction of the substrate to produce a pair (2 pieces) A substrate with a liquid crystal alignment film. In addition, the irradiation amount is a value measured using a light meter that measures with a wavelength of 313 nm as a reference. Then, for one of the pair of substrates, an epoxy resin adhesive containing aluminum oxide balls with a diameter of 5.5 μm was applied to the outer edge of the surface with the liquid crystal alignment film, and the liquid crystal alignment film faces facing each other. A pair of substrates are overlapped and pressure-bonded to harden the adhesive. Next, nematic liquid crystal (MLC-6221, manufactured by Merck) is filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic light-curing adhesive to manufacture a liquid crystal cell. Furthermore, on both outer sides of the substrate of the liquid crystal cell, the polarizing plates were bonded so that the polarization directions of the two polarizing plates were orthogonal to each other to produce a liquid crystal display element.

(3) Evaluation of the initial voltage retention rate After applying a voltage of 5 V to the liquid crystal display element immediately after manufacturing in (2) at a temperature of 60°C with an application time of 60 microseconds and a span of 167 milliseconds, The voltage holding rate (initial voltage holding rate VH ₁ ) after 167 milliseconds from the release of application was measured. The product name "VHR-1" manufactured by TOYO Corporation (Stock) was used for the measuring device. As a result, in Example 1, VH ₁ =99.6%. (4) Evaluation of light resistance Using a weather meter using a carbon arc as a light source, the liquid crystal display element after measuring the initial voltage holding ratio VH ₁ was subjected to light irradiation for 500 hours. With respect to the liquid crystal display element after light irradiation, the voltage holding ratio was measured in the same manner as in (3) above. This value was set to VH ₂ , the decrease in the voltage holding ratio obtained by subtracting VH ₂ from VH ₁ was set to ΔVHR, and the light resistance was evaluated by ΔVHR. As a result, in Example 1, ΔVHR=0.6%, and light resistance was good. (5) Evaluation of liquid crystal alignment On the respective surfaces of a pair of glass substrates without electrodes, the liquid crystal alignment agent prepared in (1) was coated and photo-aligned in the same manner as in (2) The liquid crystal alignment film is formed by processing, and a pair of substrates having the liquid crystal alignment film is used to manufacture a liquid crystal cell in the same manner as in (2). 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, by visually observing the presence or absence of alignment defects (abnormal regions) in the changes in brightness when the liquid crystal display element obtained in (2) is turned on/off (applied/released) at a voltage of 5 V, As a result, the liquid crystal display element had no alignment defects over the entire surface, and uniform alignment changes of the liquid crystals caused by voltage application were observed.

[Example 2 to Example 8, Comparative Example 1 to Comparative Example 11] Except for changing the type and amount (parts by mass) of the polymer component used in the preparation of the liquid crystal alignment agent as shown in Table 1 below, The liquid crystal alignment agent was prepared with the same solvent ratio and solid content concentration in Example 1. In addition, in addition to changing the liquid crystal alignment agent used as shown in Table 1 below, and for Comparative Example 3, Comparative Example 4, Comparative Example 6, Comparative Example 9 to Comparative Example 11, the exposure wavelength during the photo-alignment treatment was changed from 313 nm Except for changing to 365 nm and changing the irradiation dose from 500 mJ/cm ² to 4,000 mJ/cm ² , a liquid crystal display element was manufactured in the same manner as in Example 1, and the electrical characteristics and light resistance were measured in the same manner as in Example 1. Evaluation of properties and liquid crystal orientation. The results are shown in Table 1 below. In addition, under the condition that the polymer (B-1) was irradiated with polarized ultraviolet rays including bright rays of 313 nm at 500 mJ/cm ² , no photolysis 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 nematic liquid crystal (Merck, MLC-6221), with respect to the total amount of nematic liquid crystal, the polymerizable monomer was added as follows: A mixture of the compound represented by the formula (L-1) and the compound represented by the following formula (L-2) (mass mixing ratio (L-1): (L-2)=50:50) 0.5% by mass and The mixing was carried out, thereby obtaining a liquid crystal composition LC1. [化12]

(2) Manufacture of horizontal electric field type liquid crystal display element. A glass substrate with chromium-containing metal electrodes patterned into comb teeth on one surface and a counter glass substrate without electrodes are set as a pair, and the liquid crystal is aligned using a spinner Agent E (liquid crystal alignment agent used in Example 4) was coated on the side of the glass substrate with electrodes and the side of the opposite glass substrate. After pre-baking on a hot plate at 80°C for 1 minute, In an oven in which the inside was replaced with nitrogen, heating (post-baking) was performed at 200°C for 1 hour to form a coating film with a film thickness of 0.1 μm. Then, using Hg-Xe lamps and Glan-Taylor prisms, the surface of each coating film was irradiated with 300 mJ/cm ² of polarized ultraviolet light containing 313 nm bright lines from the normal direction of the substrate (photoalignment treatment) to obtain a liquid crystal alignment film A pair of substrates. On the outer periphery of the surface with the liquid crystal alignment film of one of the substrates, screen printing is used to apply an epoxy resin adhesive containing an alumina ball with a diameter of 5.5 μm to make the liquid crystal of a pair of substrates The alignment films face each other, overlapped so that the directions of the substrates when irradiated with polarized ultraviolet rays are reversed, and pressure-bonded, and the adhesive is thermally cured at 150°C for 1 hour. Then, after filling the liquid crystal composition LC1 prepared in (1) from the liquid crystal injection port toward the gap between the substrates, the liquid crystal injection port is sealed with an epoxy-based adhesive. Thereafter, in order to remove the flow alignment during liquid crystal injection, it was heated at 150°C and then slowly cooled to room temperature. Furthermore, with no voltage applied between a pair of electrodes, ultraviolet rays were applied from the outside of the liquid crystal cell (Ultraviolet, UV) light irradiation (irradiation amount: 2,000 mJ/cm ² (λ=365 nm)). Then, the polarizing plates were bonded to the outer sides of the substrate so that their polarization directions were orthogonal to each other and the optical axis of the polarized ultraviolet rays of the liquid crystal alignment film were orthogonal to the projection direction of the substrate surface, thereby manufacturing a liquid crystal display element.

(2) Evaluation With respect to the liquid crystal display element manufactured in (1) above, the electrical characteristics, light resistance, and liquid crystal orientation were evaluated in the same manner as in Example 1. As a result, in this example, VH ₁ = 99.2%, and ΔVHR = 0.3%. In addition, the liquid crystal orientation was also good as in Example 1.

[Example 10, Comparative Example 12, and Comparative Example 13] Except for changing the liquid crystal alignment agent used as shown in Table 1 below, and for Comparative Example 13, the exposure wavelength during the photo-alignment process was changed from 313 nm to 365 nm, except that the irradiation dose was changed from 500 mJ/cm ² to 4,000 mJ/cm ² , a liquid crystal display element was manufactured in the same manner as in Example 9, and the electrical characteristics, light resistance, and light resistance were measured in the same manner as in Example 1. Evaluation of liquid crystal orientation. The 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 as the polymer (A) and the polymer (B) The solution containing the polymer (B-1) obtained in Synthesis Example 5 is converted into an amount equivalent to 60 parts by mass of the polymer (B-1), and the above-mentioned synthesis example as polyorganosiloxane (C) 20 parts by mass of the polymer (C-1) obtained in 4 were mixed, and N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added to it, and the polymerizable monomer was added as the following 20 parts by mass of the compound represented by the formula (E-1) was prepared as a solution having a solvent composition of NMP:BC=50:50 (mass ratio) and a solid content concentration of 4.0% by mass. The solution was filtered with a filter having a pore diameter of 1 μm, thereby preparing a liquid crystal alignment agent T. [化13]

(2) Manufacture and evaluation of liquid crystal display elements, except that the liquid crystal alignment agent used is the liquid crystal alignment agent T prepared in (1) above, and MLC-6221 (manufactured by Merck) is used instead of the liquid crystal assembly Except that the substance LC1 was filled in the gap between the substrates, a liquid crystal display element was manufactured in the same manner as in Example 9, and the 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 retention rates of the liquid crystal display elements of Examples 1 to 11 were as high as 98.0% or more. In addition, ΔVHR was all 0.9% or less, and light resistance was also good. In addition, in Example 1 to Example 11, the alignment of the liquid crystal was also good. In contrast, in comparison with the liquid crystal alignment agents of Comparative Examples 1 to 13 and the liquid crystal alignment agents of Examples 1 to 11, at least any one of the initial voltage retention and light resistance was poor. Regarding the alignment of the liquid crystal, the alignment of the liquid crystal was not observed in Comparative Example 2, and a (meth)acrylic polymer that does not exhibit liquid crystallinity was used instead of the polymer (A) (Comparative Example 5 to Comparative Example 9) In, many alignment defects were observed when voltage was applied and released. In addition, in Comparative Example 10 where the photosensitive polyamide acid polymer (B-2) was used instead of the photosensitive polyorganosiloxane (polyorganosiloxane (C)), many alignment defects were also observed .

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Claims (7)

A liquid crystal alignment agent, comprising a polymer (A) exhibiting liquid crystallinity and a polyorganosiloxane (C) having a photo-alignment group, wherein the polymer (A) is a monomer having a polymerizable unsaturated bond The monomer of the polymerizable unsaturated bond includes one or more of the compounds represented by the following formula (2-1) to formula (2-5), and the polymer is At least one of the silicone (C) and the polymer different from the polyorganosiloxane (C) has a partial structure exhibiting liquid crystallinity in the molecule,

In formulas (2-1) to (2-5), R ² is a hydrogen atom or a methyl group, and R ³ is an alkanediyl group with 1 to 12 carbons, or at least 1 of the alkanediyl group is substituted with -O- A divalent group consisting of a methylene group, and R ⁴ is a C 1-20 alkyl group, alkoxy group or fluoroalkyl group, or a fluorine atom. The liquid crystal alignment agent described in item 1 of the scope of the patent application includes at least one polymer selected from the group consisting of polyamide acid, polyamide ester and polyimide. A liquid crystal alignment film, which is formed using the liquid crystal alignment agent described in item 1 or item 2 of the scope of patent application. A liquid crystal element comprising the liquid crystal alignment film as described in item 3 of the scope of patent application. A method for manufacturing a liquid crystal alignment film, which includes the steps of coating the liquid crystal alignment agent as described in item 1 or item 2 of the scope of the patent application on a substrate to form a coating film, and coating The step of irradiating the substrate surface of the liquid crystal alignment agent with light to impart liquid crystal alignment ability to the coating film. A method for manufacturing a liquid crystal element, comprising: forming a liquid crystal alignment film on the respective surfaces of a pair of substrates by the method for manufacturing a liquid crystal alignment film as described in item 5 of the scope of patent application; In the method of orientation, a step of arranging the pair of substrates to construct a liquid crystal cell via a liquid crystal layer containing a polymerizable monomer; and a step of irradiating the liquid crystal cell with light. A method for manufacturing a liquid crystal element, comprising: forming a liquid crystal alignment on the respective surfaces of a pair of substrates by using the method for manufacturing a liquid crystal alignment film as described in item 5 of the scope of patent application, and using a liquid crystal alignment agent containing a polymerizable monomer The step of filming; the step of arranging the pair of substrates to construct a liquid crystal cell with the respective liquid crystal alignment films facing each other through the liquid crystal layer; and the step of irradiating the liquid crystal cell with light.