WO2019116702A1 - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal element - Google Patents

Abstract

This liquid crystal aligning agent contains a polymer component and a solvent component. The solvent component contains a solvent (A) in an amount of 1-70% by mass relative to the total amount of the solvent component, while containing a solvent (B) in an amount of 0-40% by mass relative to the total amount of the solvent component. Solvent (A): At least one compound which is selected from the group consisting of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, compounds represented by formula (1) and compounds represented by formula (2). Solvent (B): A compound which is different from the solvent (A) and has a boiling point of 200°C or higher at 1 atmosphere. (In the formulae, R1 represents an alkyl group having 1-4 carbon atoms; R2 represents an alkyl group having 1-4 carbon atoms; R3 represents a hydrogen atom or an alkyl group having 1-4 carbon atoms; and n is 0 or 1.)

Description

Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal element Cross-reference to related applications

This application is based on Japanese Patent Application No. 2017-240060 filed on Dec. 14, 2017, the contents of which are incorporated herein by reference.

The present disclosure relates to a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal element.

Liquid crystal elements are used in various applications including display devices such as televisions, personal computers, and mobile phones, optical compensation films such as retardation films, and light control films. These liquid crystal elements have a liquid crystal alignment film having a function of aligning liquid crystal molecules in a predetermined direction. In general, a liquid crystal alignment film is formed by applying a liquid crystal alignment agent, in which a polymer component is dissolved in an organic solvent, on a glass or resin base and heating. As the polymer component of the liquid crystal aligning agent, polyamic acid and soluble polyimide are widely used because they are excellent in mechanical strength, liquid crystal alignment property, and affinity with liquid crystal (see, for example, Patent Documents 1 and 2) ).

JP, 2017-198975, A JP, 2016-206645, A

If coating unevenness (in-plane unevenness) occurs on the surface of the alignment film due to repelling or non-uniformity of the liquid crystal alignment agent when the liquid crystal alignment agent is applied on the substrate, the product yield decreases And the liquid crystal alignment of the resulting liquid crystal element may not be sufficient. Such coating unevenness causes the thickness of the liquid crystal alignment film to be relatively thick (for example, 0.3 μm) in order to, for example, enhance the alignment of the liquid crystal by the liquid crystal alignment film or enhance the adhesion between the liquid crystal alignment film and the substrate. More likely to occur if That is, when the film thickness of the liquid crystal alignment film is increased, the solvent can not be sufficiently removed in the heating step for film formation, and coating unevenness easily occurs on the surface of the alignment film due to the influence of the residual solvent in the alignment film. In this case, there is a concern that the liquid crystal alignment of the liquid crystal element to be obtained is not sufficient.

Further, for example, in the roll-to-roll method, in the process of manufacturing a liquid crystal element, the substrate on which the alignment film is formed may be overlapped in a roll shape and temporarily stored. When the amount of the solvent remaining in the alignment film is large, the offset of the polymer component and the remaining solvent in the alignment film to the substrate side is easily caused. In addition, when offset to the substrate side occurs, there is a concern that the liquid crystal alignment film may be easily peeled off from the substrate, or the liquid crystal alignment of the liquid crystal element to be obtained may be deteriorated.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a liquid crystal aligning agent having good coatability to a substrate and capable of sufficiently reducing the residual solvent in the alignment film. Do.

MEANS TO SOLVE THE PROBLEM This inventor earnestly examined in order to solve the said subject, and found out that the said subject is solvable by containing the specific solvent of a comparatively low boiling point as a solvent component of a liquid crystal aligning agent. Specifically, the present disclosure adopts the following means in order to solve the problems.

<1> A polymer component and a solvent component are contained, and the solvent component is 1 to 70 mass% of the following solvent (A) with respect to the total amount of the solvent component, and the following solvent (B) solvent Liquid crystal aligning agent containing 0 to 40% by mass with respect to the total amount of
(A) Solvent: a group consisting of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, a compound represented by the following formula (1), and a compound represented by the following formula (2) At least one compound selected from
(B) Solvent: a compound having a boiling point of 200 ° C. or higher at atmospheric pressure and different from the solvent (A).

(In the formula (1), R ¹ is an alkyl group having 1 to 4 carbon atoms.)

(In formula (2), R ² is an alkyl group having 1 to 4 carbon atoms, R ³ is an alkyl group having 1 to 4 carbon atoms. N is 0 or 1.)
<2> Liquid crystal aligning film formed using liquid crystal aligning agent of said <1><3> The liquid crystal element which comprises the liquid crystal aligning film of said <2>.
The manufacturing method of the liquid crystal aligning film which apply | coats the liquid crystal aligning agent of <4> said <1> on a base material, and heats at 150 degrees C or less, and forms a coating film.

The liquid crystal aligning agent of the present disclosure has good coatability with respect to a substrate, and can sufficiently remove the solvent in the liquid crystal aligning agent at the time of heating at the time of forming the alignment film. It can be sufficiently reduced. Thereby, a decrease in product yield can be suppressed, and a high quality liquid crystal element can be obtained.

Below, each component contained in the liquid crystal aligning agent of this indication, and the other component arbitrarily mix | blended as needed are demonstrated. The liquid crystal aligning agent of the present disclosure contains a polymer component and a solvent component. The liquid crystal aligning agent is a liquid polymer composition in which a polymer component is dissolved in a solvent component.

«Polymer component»
The main skeleton of the polymer component contained in the liquid crystal aligning agent is not particularly limited. For example, polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyamide, polyamide imide, polybenzoxazole precursor, polybenzo Main skeletons such as oxazole, cellulose derivative, polyacetal, styrene-maleimide copolymer, poly (meth) acrylate and the like can be mentioned. In addition, (meth) acrylate is meant to include acrylate and methacrylate. From the viewpoint of sufficiently securing the performance of the liquid crystal element, etc., the polymer component is selected from the group consisting of polyamic acid, polyimide, polyamic acid ester, polyamide imide, poly (meth) acrylate, and polyorganosiloxane among the above. Selected from the group consisting of poly (meth) acrylates and polyorganosiloxanes in that heating at the time of film formation can be performed at a lower temperature, and at least one polymer (hereinafter referred to as "(P) polymer") At least one is more preferred.

(Photosensitive group-containing polymer)
As the polymer (P), a part or all of the content contained in the liquid crystal alignment agent may be used as a polymer having a photosensitive structure (hereinafter, also referred to as a “photosensitive group-containing polymer”). The photosensitive structure may be any structure or functional group that is sensitive to light to cause a reaction, and includes photoalignable groups and polymerizable groups.
When the polymer (P) has a photoalignable group, it becomes possible to impart liquid crystal alignment to a coating film produced using a liquid crystal aligning agent by the photoalignment method. Thereby, the effect by applying the light alignment method, specifically, the effect of suppressing the occurrence of display defects and the decrease in yield due to the generation of dust and static electricity, and the like, to the organic thin film formed on the substrate This is preferable in that the effect of being able to uniformly impart the liquid crystal alignment ability is obtained. In addition, when the (P) polymer has a polymerizable group, the adhesion of the liquid crystal alignment film to the substrate can be enhanced, and the reduction in product yield can be further suppressed when manufacturing a liquid crystal device to which a roll-to-roll system is applied. It is preferable in that it can be

The photoalignable group is a functional group that imparts anisotropy to the film by a photoisomerization reaction by light irradiation, a photodimerization reaction, a photolysis reaction, a light fleece rearrangement reaction, or the like. Specific examples thereof include an azobenzene structure containing azobenzene or a derivative thereof as a basic skeleton, a cinnamic acid structure containing cinnamic acid or a derivative thereof as a basic skeleton, a chalcone structure containing chalcone or a derivative thereof as a basic skeleton, benzophenone or the like A benzophenone structure containing a derivative as a basic skeleton, a coumarin structure containing coumarin or a derivative thereof as a basic skeleton, a stilbene structure containing stilbene or a derivative thereof as a basic skeleton, a diphenylacetylene structure containing diphenylacetylene or a derivative thereof as a basic skeleton Examples thereof include a phenylbenzoate structure containing phenyl benzoate or a derivative thereof as a basic skeleton, and a cyclobutane structure containing cyclobutane or a derivative thereof as a basic skeleton. Among these, it is particularly preferable that the photoalignable group that the (P) polymer has is a group having a cinnamic acid structure, from the viewpoint of high reactivity with light.

Specifically, the group having a cinnamic acid structure preferably has a partial structure represented by the following formula (4).

(In the formula ^{(4), R 31} and ^{R 32} each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, is ^{.R 33} is an alkoxy group or a cyano group having 1 to 3 carbon atoms A halogen atom, an alkyl group of 1 to 3 carbon atoms, an alkoxy group of 1 to 3 carbon atoms or a cyano group, a 1 is an integer of 0 to 4. However, when a 1 is 2 or more, plural R ³³ May be the same or different, "*" indicates that it is a bond.)

As a group represented by the said Formula (4), the substituent was introduce | transduced into the benzene ring which the monovalent group obtained by removing the hydrogen atom of the carboxyl group which cinnamic acid has, or the said monovalent group has. Group (hereinafter, these are also referred to as “forward cinnamate group”), and a monovalent group in which a carboxyl group possessed by cinnamic acid is esterified, and a divalent organic group is bonded to a benzene ring, or And groups in which a substituent is introduced into the benzene ring possessed by the divalent group (hereinafter, these are also referred to as “reverse cinnamate group”) and the like. The forward cinnamate group is represented, for example, by the following formula (cn-1). The reverse cinnamate group is represented, for example, by the following formula (cn-2).

(In the formula (cn-1), R ³⁴ represents a hydrogen atom, a halogen atom, an alkyl group of 1 to 3 carbon atoms, an alkoxy group of 1 to 3 carbon atoms, or a cyano group. R ³⁵ represents a phenylene group or biphenylene Group, a terphenylene group or a cyclohexylene group, or at least a part of hydrogen atoms of a phenylene group, a biphenylene group, a terphenylene group or a cyclohexylene group is a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, It is a group substituted by any of an alkoxy group having 1 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms.A ¹¹ is a single bond, an oxygen atom, a sulfur atom, or an alkanediyl having 1 to 3 carbon atoms. ^{group, -CH = CH -, - NH} -, * 2 -COO -, * 2 -OCO -, * 2 -NH-CO -, * 2 -CO-NH -, * 2 -CH -O- or _{^{* 2 -O-CH 2 -.}} (. ^{"* 2"} to bond indicates a between ^{R 35)} is .b1 is 0 or 1, "*" indicates a bond .
In the formula (cn-2), R ³⁶ is an alkyl group having 1 to 3 carbon atoms. A ¹² represents an oxygen atom, * ² -COO-, * ² -OCO-, * ² -NH-CO- or * ² -CO-NH- (“* ² ” represents a bond to R ³⁷ ) It is. R ³⁷ is an alkanediyl group having 1 to 6 carbon atoms. c1 is 0 or 1; "*" Indicates that it is a bond.
R ³¹ , R ³² , R ³³ and a 1 are as defined in the above formula (4). )

The polymerizable group is preferably a functional group that is sensitive to light and causes a crosslinking reaction, for example, (meth) acryloyl group, vinyl group (vinylphenyl group and vinyloxy group (CH ₂ = CH-O-), etc. And vinylidene groups, maleimide groups, allyl groups, ethynyl groups, allyloxy groups, epoxy groups and the like. Among these, a (meth) acryloyl group or a vinyl group is preferable in that it is highly reactive to light. The (meth) acryloyl group is a meaning that includes an acryloyl group and a methacryloyl group, and the epoxy group is a meaning that includes an oxiranyl group and an oxetanyl group.

Among these, the photosensitive structure of the (P) polymer is selected from the group consisting of cinnamic acid structure, azobenzene structure, chalcone structure, stilbene structure, diphenylacetylene structure, (meth) acryloyl group, vinyl group, and phenylbenzoate structure. It is preferably at least one selected, particularly preferably a cinnamic acid structure or a (meth) acryloyl group. When the polymer (P) has a photosensitive structure, the content ratio of the photosensitive structure is preferably 10 mol% or more with respect to the total amount of the monomer units constituting the polymer (P), It is more preferable that it is 20 mol% or more.

(P) When a polymer having a photoalignable group is used as the polymer, all of the polymer components of the liquid crystal aligning agent may be a polymer having a photoalignable group, and a part of the polymer may be a photoalignable group. It is good also as a polymer which it has. In the case of using a polymer having a photoalignable group for a part of the polymer component, the use ratio of the polymer is 1 to 80% by mass with respect to the total amount of the polymer component used for preparation of the liquid crystal alignment agent It is preferable that the amount be 2 to 70% by mass.
Moreover, when using the polymer which has a polymeric group as (P) polymer, the usage ratio of the said polymer is 1-80 mass% with respect to the whole quantity of the polymer component used for preparation of a liquid crystal aligning agent. It is preferably set to 2 to 70% by mass. In addition, a photosensitive group containing polymer may be used individually by 1 type, and 2 or more types may be mixed and used.

(Liquid crystalline polymer)
As the polymer (P), a partial structure (hereinafter also referred to as "liquid crystalline structure") exhibiting liquid crystallinity in a predetermined temperature range is used as a side chain for a part or all of the content contained in the liquid crystal aligning agent. It may be used as a polymer (hereinafter also referred to as "liquid crystalline polymer"). By containing a liquid crystalline polymer in the liquid crystal aligning agent, it is preferable in that the initial voltage holding ratio of the liquid crystal element can be further increased.

The liquid crystalline structure includes a structure having a rigid portion (mesogen structure), and a specific example thereof includes a structure having a group represented by the following formula (5).

(In Formula (5), Ar ¹ and Ar ² are each independently a substituted or unsubstituted phenylene group or a substituted or unsubstituted cyclohexylene group, and X ²¹ is a single bond, —CO—, —COO -, - C = C -, - C≡C -, - N = N- or ^{-CONR 41} - ^{(. R} 41 is a hydrogen atom or a monovalent organic group) and is .r is an integer of 1 to 3 When r is 2 or 3, each of Ar ² and X ²¹ independently has the above-mentioned definition. “*” Represents a bonding hand.)

In the above formula (5), X ²¹ is preferably a single bond or —COO—. Examples of the monovalent organic group of R ⁴¹ include an alkyl group having 1 to 6 carbon atoms, a protecting group and the like. Specific examples of the protective group include, for example, t-butoxycarbonyl group, benzyloxycarbonyl group, 1,1-dimethyl-2-haloethyloxycarbonyl group, allyloxycarbonyl group and the like, and t-butoxycarbonyl group is preferable. . 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 (5) include, for example, 4,4′-biphenylene group, 4,4′-bicyclohexylene group, p-terphenylene group, and the following formula (5-1) And groups having a methyl group or a fluorine atom in the ring portion of these groups, and the like. The “*” in the above formula (5) and the following formulas (5-1) to (5-4) may be bonded to a hydrogen atom.

(In the formula, "*" indicates a bond.)

When the polymer (P) is a liquid crystalline polymer, a polymer having a photosensitive group in a side chain can be preferably used as the liquid crystalline polymer. Specifically, the liquid crystalline polymer preferably has a group represented by each of the following formulas (F-1) to (F-7) in the side chain.

(In Formula (F-1) to Formula (F-7), A ¹ and B ¹ and D ¹ are each independently a single bond, —O—, —CH ₂ —, —COO—, —OCO—, B ² is a single bond, -COO-, -OCO-, -N = N-, -C = C-, -C≡C- or a phenylene group. Y ¹ is a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a pyrrole ring, or a monovalent cyclic group having a cyclic hydrocarbon with 5 to 8 carbon atoms, and at least one hydrogen atom bonded to the ring is It may be substituted by a halogen atom, a nitro group, a cyano group, -C = C (CN) ₂ , -C = CH-CN, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms Y ² is a benzene ring, naphthalene ring, biphenyl ring, furan ring, pyrrole ring, or carbon number A divalent cyclic group having 5 to 8 cyclic hydrocarbons, at least one hydrogen atom bonded to the ring being a halogen atom, a nitro group, a cyano group, -C = C (CN) ₂ , -C = CH It may be substituted by —CN, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms. Y ³ is a monovalent cyclic group having a benzene ring, a naphthalene ring or a biphenyl ring. And at least one hydrogen atom bonded to the ring is a halogen atom, a nitro group, a cyano group, -C = C (CN) ₂ , -C = CH-CN, an alkyl group having 1 to 3 carbon atoms, or a carbon number It may be substituted by 1 to 3 alkoxy groups, and X ¹ is a single bond, -COO-, -OCO-, -N = N-, -C = C-, -C≡C- or phenylene group. R ¹¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. R ¹² represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, -C = C (CN) ₂ , -C = CH-CN, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms R ¹³ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, k is an integer of 1 to 12, m and j are each independently an integer of 1 to 3, and g is 1 And at least one hydrogen atom bonded to a benzene ring in formula (F-6) is a halogen atom, a nitro group, a cyano group, -C = C (CN) ₂ , -C. It may be substituted with ア ル キ ル CH—CN, an alkyl group of 1 to 3 carbon atoms, or an alkoxy group of 1 to 3 carbon atoms “* 1” indicates a bond to be bonded to the main chain. )

When a part or all of the polymer (P) is a liquid crystalline polymer, the liquid crystalline polymer is preferably at least one selected from the group consisting of poly (meth) acrylates, polyamic acids, polyimides and polyamic acid esters. And poly (meth) acrylates are particularly preferred. (P) When a liquid crystalline polymer is used as the polymer, the use ratio of the liquid crystalline polymer is appropriately set in a range of 100% by mass or less based on the total amount of the polymer components used for the preparation of the liquid crystal aligning agent. Can. In addition, as a liquid crystalline polymer, 1 type may be used independently and 2 or more types may be mixed and used.

(Synthesis of polymer)
The polymer (P) can be obtained by appropriately combining conventional methods of organic chemistry according to the main skeleton thereof. The polyamic acid, the polyimide, the polyamic acid ester, the polyamide imide, the poly (meth) acrylate, and the polyorganosiloxane are respectively described below.

[Polyamic acid]
The polyamic acid can be obtained by reacting tetracarboxylic acid dianhydride with a diamine compound.

(Tetracarboxylic acid dianhydride)
Examples of tetracarboxylic acid dianhydrides used in the synthesis of polyamic acids include aliphatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic acid dianhydrides, and aromatic tetracarboxylic acid dianhydrides. . As specific examples of these, as aliphatic tetracarboxylic acid dianhydride, for example, 1,2,3,4-butanetetracarboxylic acid dianhydride etc .;
Examples of alicyclic tetracarboxylic acid dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 2,3,5-Tricarboxycyclopentylacetic 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, 3-Oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), 2,4,6,8-tetracarboxybicyclo [ 3.3.0] Octane -2: 4,6: 8 dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^{2, 6]} undecane -3,5,8,10- tetraone, cyclopentane tetracarboxylic Acid dianhydrides, cyclohexane tetracarboxylic acid dianhydrides and the like; as aromatic tetracarboxylic acid dianhydrides, for example, pyromellitic dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, ethylene Glycol bisanhydrotrimate, 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, etc .; The tetracarboxylic acid dianhydride described in the publication can be used. In addition, the said tetracarboxylic dianhydride can be used individually by 1 type or in combination of 2 or more types.

(Diamine compound)
As a diamine compound used for the synthesis | combination of a polyamic acid, an aliphatic diamine, an alicyclic diamine, aromatic diamine, a diamino organosiloxane etc. can be mentioned, for example. Specific examples of these diamines include, as aliphatic diamines, for example, metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine and the like; as alicyclic diamines, for example, 1,4 -Diaminocyclohexane, 4,4'- methylenebis (cyclohexylamine) and the like;
As aromatic diamines, for example, dodecanoxydiaminobenzene, octadecanoxydiaminobenzene, cholestanyloxydiaminobenzene, cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, 3,6-bis (4-aminobenzoyloxy) cholestane, 3 , 6-Bis (4-aminophenoxy) cholestane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl , The following formula (E-1)

(In formula (E-1), X ^I and X ^II each independently represent a single bond, -O-, * -COO- or * -OCO- (wherein "*" represents a bond to X ^I R ¹ is an alkanediyl group having 1 to 3 carbon atoms, R ^II is a single bond or an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, and b is 0. And is an integer of to 2, c is an integer of 1 to 20, and d is 0 or 1. However, a and b can not be 0 simultaneously.)
And an alignment group-containing diamine such as a compound represented by the following formula, a diamine having a cinnamic acid structure, and a diamine having a liquid crystalline structure:

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-diaminopyridine, 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, 4,4 '-Diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis (4-aminophenyl) Subfluoropropane, 4,4 '-(phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl etc. as a diaminoorganosiloxane For example, 1,3-bis (3-aminopropyl) -tetramethyldisiloxane and the like can be mentioned, respectively, and diamines described in JP-A-2010-97188 can be used.

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

The synthesis reaction of polyamic acid 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 to 24 hours.
Examples of the organic solvent used for the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons and the like. Particularly preferred organic solvents are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol And using one or more selected from the group consisting of and halogenated phenols as a solvent, or using a mixture of one or more of these and another organic solvent (eg, butyl cellosolve, diethylene glycol diethyl ether, etc.) preferable. The amount (a) of the organic solvent used is such that the total amount (b) of the tetracarboxylic acid dianhydride and the diamine is 0.1 to 50% by mass with respect to the total amount (a + b) of the reaction solution. Is preferred.
As described above, a reaction solution in which the polyamic acid is dissolved is obtained. This reaction solution may be used as it is for preparation of a liquid crystal aligning agent, or may be used for preparation of a liquid crystal aligning agent after the polyamic acid contained in the reaction solution is isolated.

[Polyamic acid ester]
(P) When the polymer is a polyamic acid ester, the polyamic acid ester is, for example, [I] a method of reacting a polyamic acid obtained by the above synthesis reaction with an esterifying agent, [II] tetracarboxylic acid diester These compounds can be obtained by a method of reacting a diamine compound with a diamine compound, a method of reacting a [III] tetracarboxylic acid diester dihalide with a diamine compound, or the like. The polyamic acid ester to be contained in the liquid crystal aligning agent may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester may be used as it is for preparation of a liquid crystal aligning agent, or the polyamic acid ester contained in the reaction solution may be isolated and then provided for preparation of a liquid crystal aligning agent. Good.

[Polyimide]
When the polymer (P) is a polyimide, the polyimide can be obtained, for example, by dehydration ring closure and imidization of the polyamic acid synthesized as described above. The polyimide may be a completely imidized product obtained by dehydrating and ring closing all of the amic acid structure of the precursor polyamic acid, and only a part of the amic acid structure may be dehydrating and ring closing, and the amic acid structure and the imide. It may be a partial imidate coexisting with a ring structure. The polyimide used for the reaction preferably has an imidation ratio of 20 to 99%, more preferably 30 to 90%. The imidation ratio is a percentage representing the ratio of the number of imide ring structures to the total number of amic acid structures of polyimide and the number of imide ring structures. Here, part of the imide ring may be an isoimide ring.

The dehydration ring closure of the polyamic acid is preferably carried out by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to this solution, and heating as necessary. In this method, as the dehydrating agent, for example, an acid anhydride such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride and the like can be used. The amount of the dehydrating agent used is preferably 0.01 to 20 moles relative to 1 mole of the polyamic acid's amic acid structure. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used. The amount of the dehydrating ring-closing catalyst used is preferably 0.01 to 10 moles relative to 1 mole of the dehydrating agent used. As an organic solvent used for a dehydration ring-closing reaction, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C. The reaction time is preferably 1.0 to 120 hours. Thus, a reaction solution containing a polyimide is obtained. This reaction solution may be used as it is for preparation of a liquid crystal aligning agent, or may be used for preparing a liquid crystal aligning agent after isolating the polyimide. Polyimides can also be obtained by imidization of polyamic acid esters.

The polyamic acid, polyamic acid ester and polyimide obtained as described above preferably have a solution viscosity of 10 to 800 mPa · s when this is made into a solution with a concentration of 10% by mass, preferably 15 to 500 mPa. More preferably, it has a solution viscosity of s. The solution viscosity (mPa · s) of the polyamic acid, polyamic acid ester and polyimide is 10% by mass of a solution prepared using a good solvent of these polymers (eg, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) The polymer solution of the above was a value measured at 25.degree. C. using an E-type rotational viscometer.

The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of polyamic acid, polyamic acid ester and polyimide is preferably 1,000 to 500,000, and more preferably 2,000 to 500 It is 300,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less. By being in such a molecular weight range, good alignment and stability of the liquid crystal display element can be secured.

[Polyamide imide]
Polyamide imide is, for example, a method of condensation reaction of tricarboxylic acid and diisocyanate compound, or reaction of tricarboxylic acid and diamine compound to introduce an imide bond into the molecule, and then reaction of this with diisocyanate compound to amidate It can be obtained by the method.

Examples of tricarboxylic acids used in the synthesis of polyamideimides include trimellitic anhydride, butane-1,2,4-tricarboxylic acid, and naphthalene-1,2,4-tricarboxylic acid. Examples of the diisocyanate compound include diphenylmethane-4,4'-diisocyanate, diphenylether-4,4'-diisocyanate, tolylene diisocyanate and xylene diisocyanate. As a diamine compound, the diamine compound etc. which were illustrated by the synthesis | combination of polyamic acid are mentioned.

The above reaction is preferably carried out in an organic solvent. In the synthesis of the polyamideimide, the proportion of the monomer used is preferably such that the number of isocyanate groups or amino groups is 0.85 to 1.05 moles with respect to 1 mole of the total of the carboxyl group and the acid anhydride group. The synthesis reaction of polyamideimide 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 to 24 hours. As an organic solvent used for reaction, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. The weight average molecular weight (Mw) in terms of polystyrene measured by GPC for the obtained polyamideimide is preferably 5,000 to 100,000, and more preferably 7,000 to 80,000.

[Polyorganosiloxane]
The polyorganosiloxane can be obtained, for example, by hydrolyzing and condensing a hydrolyzable silane compound. Examples of silane compounds used for the synthesis of polyorganosiloxanes include alkoxysilane compounds such as tetramethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and dimethyldiethoxysilane; 3-mercaptopropyltriethoxy Nitrogen / sulfur-containing alkoxysilane compounds such as silane, mercaptomethyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (3-cyclohexylamino) propyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3- Epoxy group-containing silane compounds such as glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, etc. And unsaturated alkoxysilane compounds of the following: trimethoxysilylpropyl succinic anhydride and the like. The hydrolyzable silane compounds can be used alone or in combination of two or more of them. In addition, "(meth) acryloxy" is a meaning including "acryloxy" and "methacryloxy."

The above-mentioned hydrolysis / condensation reaction is carried out by reacting one or more silane compounds as described above with water, preferably in the presence of a suitable catalyst and an organic solvent. In the reaction, the proportion of water used is preferably 1 to 30 moles relative to 1 mole of the silane compound (total amount). As a catalyst to be used, an acid, an alkali metal compound, an organic base, a titanium compound, a zirconium compound etc. can be mentioned, for example. The amount of catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, etc., and should be set appropriately. For example, it is preferably 0.01 to 3 times the molar amount of the total amount of silane compounds. . Examples of the organic solvent to be used include hydrocarbons, ketones, esters, ethers, alcohols and the like, and among these, it is preferable to use a water insoluble or poorly water soluble organic solvent. The proportion of the organic solvent used is preferably 10 to 10,000 parts by mass with respect to 100 parts by mass in total of the silane compound used for the reaction.

The above hydrolysis / condensation reaction is preferably carried out, for example, by heating with an oil bath or the like. At that time, the heating temperature is preferably 130 ° C. or less, and the heating time is preferably 0.5 to 12 hours. After completion of the reaction, the organic solvent layer separated from the reaction solution is dried with a desiccant if necessary, and the solvent is removed to obtain the target polyorganosiloxane. The method for synthesizing polyorganosiloxane is not limited to the above-mentioned hydrolysis / condensation reaction, and may be performed by, for example, a method of reacting a hydrolyzable silane compound in the presence of oxalic acid and alcohol.

The polyorganosiloxane may be a polyorganosiloxane having a photosensitive structure or a liquid crystalline structure in its side chain. The method for synthesizing the polyorganosiloxane is not particularly limited, but a polyorganosiloxane having an epoxy group in a side chain using an epoxy group-containing silane compound as at least a part of the raw material (hereinafter, "epoxy group-containing polyorganosiloxane") And a method of reacting an epoxy group-containing polyorganosiloxane with a carboxylic acid having a photosensitive structure or a liquid crystalline structure, and the like. This method is preferable in that it is simple and can increase the introduction ratio of the photosensitive structure and the liquid crystalline structure. In addition, a polyorganosiloxane having a photosensitive structure or a liquid crystalline structure in a side chain may be synthesized by a reaction in which a hydrolyzable silane compound having a photosensitive structure or a liquid crystalline structure is contained in a monomer. The weight average molecular weight (Mw) in terms of polystyrene measured by GPC for polyorganosiloxane is preferably in the range of 100 to 50,000, and more preferably in the range of 200 to 10,000.

[Poly (meth) acrylate]
Poly (meth) acrylate can be obtained by polymerizing a monomer containing a (meth) acrylic compound. Examples of (meth) acrylic compounds include unsaturated carboxylic acids such as (meth) acrylic acid, α-ethyl acrylic acid, maleic acid, fumaric acid and vinylbenzoic acid; alkyl (meth) acrylates (meth) acrylic acid Cycloalkyl, benzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, trimethoxysilylpropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, (meth) Unsaturated carboxylic acid esters such as 3,4-epoxycyclohexylmethyl acrylic acid, 3,4-epoxybutyl (meth) acrylic acid, 4-hydroxybutyl glycidyl ether acrylic acid; unsaturated polyhydric carboxylic acid anhydrides such as maleic anhydride Things, etc. In the polymerization, as the (meth) acrylic compound, one kind may be used alone, or two or more kinds may be used in combination.

In the synthesis of poly (meth) acrylate, monomers other than (meth) acrylic compounds may be used. As the monomer, for example, aromatic vinyl compounds such as styrene, methylstyrene and divinylbenzene; conjugated diene compounds such as 1,3-butadiene and 2-methyl-1,3-butadiene; N-methylmaleimide, N-cyclohexyl Examples thereof include maleimide group-containing compounds such as maleimide and N-phenyl maleimide. These monomers can be used singly or in combination of two or more.
The proportion of monomers other than (meth) acrylic compounds is preferably 50 mol% or less, more preferably 40 mol% or less, and more preferably 30 mol or less, based on the total amount of monomers used for polymerization. It is further preferable to

Poly (meth) acrylate can be obtained by polymerizing the above-mentioned monomer in the presence of a polymerization initiator. As a polymerization initiator to be used, for example, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2 Azo compounds such as 4, 4-dimethylvaleronitrile) are preferred. The proportion of the polymerization initiator used is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of all the monomers used for the reaction.

The above polymerization reaction is preferably carried out in an organic solvent. Examples of the organic solvent used for the reaction include alcohols, ethers, ketones, amides, esters, hydrocarbon compounds and the like, and diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether acetate and the like are preferable. The reaction temperature is preferably 30 ° C. to 120 ° C., and the reaction time is preferably 1 to 36 hours. The amount (a) of the organic solvent used should be such that the total amount (b) of the monomers used in the reaction is 0.1 to 60% by mass with respect to the total amount (a + b) of the reaction solution Is preferred.

When poly (meth) acrylate is used as a photosensitive group-containing polymer or a liquid crystalline polymer, the synthesis method is not particularly limited. For example, (I) a hydrolyzable silane compound having a photosensitive structure or a liquid crystalline structure as a monomer (II) a polymer having an epoxy group in a side chain using an epoxy group-containing compound as at least a part of the raw material, and then a carbon having a photosensitive structure or a liquid crystalline structure The method of making it react with an acid, etc. are mentioned. The weight average molecular weight (Mw) in terms of polystyrene measured by GPC for the poly (meth) acrylate is preferably 250 to 500,000, more preferably 500 to 100,000, and 1,000 to 50. Is more preferably 1,000.

«Solvent composition»
The liquid crystal aligning agent of the present disclosure includes, as at least a part of a solvent component, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, a compound represented by the above formula (1), and the above formula It contains (A) a solvent which is at least one selected from the group consisting of compounds represented by (2).

[(A) solvent]
In the above formulas (1) and (2), the alkyl group of R ¹ , R ² and R ³ may be linear or branched and, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n- Examples include butyl, isobutyl and tert-butyl. Among these, R ¹ preferably has 3 or 4 carbon atoms, and more preferably an n-propyl group or an n-butyl group. R ² preferably has 1 or 2 carbon atoms. R ³ is preferably a methyl group. In the above formula (2), n is 0 or 1, preferably 0.

Specific examples of the compound represented by the above formula (1) include propylene glycol methyl ethyl ether, propylene glycol dimethyl ether, propylene glycol methyl n-propyl ether, and propylene glycol methyl n-butyl ether. Preferred is propylene glycol methyl-n-propyl ether or propylene glycol methyl-n-butyl ether. In addition, as a compound represented by the said Formula (1), 1 type may be used independently and may be used combining 2 or more types.

Specific examples of the compound represented by the above formula (2) include cyclohexyl acetate, cyclohexyl propionate, cyclohexyl butyrate, cyclohexyl pentanoate and the like. Preferably, it is cyclohexyl acetate or cyclohexyl propionate. In addition, as a compound represented by the said Formula (2), 1 type may be used independently and you may use it in combination of 2 or more type.

[(B) solvent]
The solvent component, together with the solvent (A), has a boiling point of 200 ° C. or higher at 1 atmospheric pressure in that it can sufficiently suppress the occurrence of coating unevenness even when the film thickness of the liquid crystal alignment film is thickened (A It is preferable to further include (B) a solvent different from the solvent).

The solvent (B) is preferably at least one selected from the group consisting of aprotic polar solvents and phenols, and is more preferably aprotic polar solvents. Specifically, a group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, gamma-butyrolactone, and a compound represented by the following formula (3) Particularly preferred is at least one selected from

(In the formula (3), R ⁴ and R ⁵ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms which may have an ether bond, and R ⁴ and R ⁵ may combine with each other to form a ring structure, and R ⁶ is an alkyl group having 1 to 4 carbon atoms.

(Compound represented by formula (3))
In the above formula (3), examples of the monovalent hydrocarbon group having 1 to 6 carbon atoms of R ⁴ and R ⁵ include, for example, a chain hydrocarbon group having 1 to 6 carbon atoms and an alicyclic group having 3 to 6 carbon atoms. A hydrocarbon group, an aromatic hydrocarbon group having 5 or 6 carbon atoms and the like can be mentioned. The monovalent group having an ether bond includes, for example, an alkoxyalkyl group having 2 to 6 carbon atoms. The ring R ^4, R ⁵ are bonded to each other R ⁴ and R ⁵ are formed together with the nitrogen atom to which they are attached such as pyrrolidine ring, and a nitrogen-containing heterocyclic ring such as a piperidine ring. A monovalent chain hydrocarbon group such as a methyl group may be bonded to these nitrogen-containing heterocycles.
R ⁴ and R ⁵ are preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, still more preferably a hydrogen atom or a methyl group . The alkyl group having 1 to 4 carbon atoms of R ⁶ may be linear or branched. R ⁶ is preferably a methyl group or an ethyl group.

Specific examples of the compound represented by the above formula (3) include, for example, 3-butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide, 3-hexyloxy-N, N- Dimethylpropanamide, isopropoxy-N-isopropyl-propionamide, n-butoxy-N-isopropyl-propionamide and the like. The compounds represented by the above formula (3) can be used singly or in combination of two or more.

[(C) solvent]
The solvent component may further contain a solvent other than the (A) solvent and the (B) solvent (hereinafter, also referred to as "(C) solvent"). The solvent (C) is not particularly limited as long as it is a solvent different from the solvents (A) and (B) as long as the effects of the present disclosure are not impaired. The solvent (C) is preferably at least one selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons. As specific examples of these, as alcohols, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, diacetone alcohol and the like;
As ketones, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone etc .;
As esters, for example, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, diethyl oxalate, diethyl malonate, isoamyl propionate, isoamyl isobutyt Rate etc;
As ethers, for example, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol i-propyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl Ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether (PGME), propylene glycol mono Chill ether acetate (PGMEA), tetrahydrofuran, a di-isopentyl ether and the like;
As halogenated hydrocarbons, for example, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene and the like;
Examples of hydrocarbons include, for example, hexane, heptane, octane, cyclopentane, cyclohexane, benzene, toluene, xylene and the like. In addition, as (C) solvent, it can be used individually by 1 type or in combination of 2 or more types.

Among these, the solvent (C) is preferably at least one selected from the group consisting of ketones, esters, ethers, and hydrocarbons from the viewpoint of being able to suitably suppress the coating unevenness. . Among the above, it is preferable to use a low boiling point solvent having a boiling point of 180 ° C. or less at 1 atmospheric pressure, in that the liquid crystal alignment film can be formed by low temperature firing and the application of the film substrate is possible. Specifically, it is preferably one selected from the group consisting of propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, cyclohexanone, cyclopentane and cyclopentanone.

Among the solvent components, the content ratio of the solvent (A) is 1 to 70% by mass with respect to the total amount of the solvent components contained in the liquid crystal aligning agent. When it is less than 1% by mass, the effect of improving the coating properties of the liquid crystal aligning agent and the effect of reducing the solvent remaining in the alignment film are small, while when it is more than 70% by mass, the solubility of the polymer is lowered. As a result, the effect of suppressing the application unevenness of the alignment film is small. The content ratio of the solvent (A) is preferably 3 to 65% by mass, more preferably 5 to 60% by mass.

The content ratio of the solvent (B) is 0 to 40% by mass with respect to the total amount of solvent components contained in the liquid crystal aligning agent. When the content ratio of the solvent (B) is more than 40% by mass, the amount of the solvent remaining in the alignment film is excessively large, which is not preferable in that the offset easily occurs. In addition, "containing 0 mass% of (B) solvent" means not containing (B) solvent in a liquid crystal aligning agent. It is preferable that a relatively small amount of (B) solvent is contained together with the (A) solvent in the liquid crystal aligning agent in that a liquid crystal alignment film in which coating unevenness is less likely to occur even when the film thickness is made can be obtained. . Specifically, the content ratio of the solvent (B) is set to 0.1 to 40% by mass with respect to the total amount of the solvent components contained in the liquid crystal aligning agent in that the effect of suppressing the coating unevenness can be further enhanced. Is preferably 0.5 to 40% by mass, more preferably 1 to 35% by mass, and particularly preferably 1 to 20% by mass.

The content ratio of the solvent (C) is preferably 5 to 98% by mass, more preferably 10 to 95% by mass, with respect to the total amount of the solvent component contained in the liquid crystal aligning agent, and more preferably 20 to 90 It is more preferable to use mass%. Even when heating at the time of film formation is performed at low temperature (for example, at 150 ° C. or less), the content ratio of the solvent (C) is contained in the liquid crystal aligning agent because the amount of residual solvent in the liquid crystal alignment film can be sufficiently reduced. It is more preferable to set it as 40 mass% or more with respect to the whole quantity of the solvent component to be carried out, and it is still more preferable to set it as 50 mass% or more. In this case, by setting the polymer component to at least one selected from the group consisting of poly (meth) acrylate and polyorganosiloxane, the solubility of the polymer in the solvent can be made better, and the coating unevenness can be sufficiently suppressed. It is preferable at the point which can be done. The liquid crystal aligning agent is preferably a mixed solvent in which the solvent components include (A) solvent and (B) solvent, and is a mixed solvent consisting of (A) solvent, (B) solvent and (C) solvent Is particularly preferred.

«Other ingredients»
The liquid crystal aligning agent contains a polymer component and a solvent component, but may contain other components as needed. As such other components, for example, epoxy group-containing compounds, functional silane compounds, antioxidants, metal chelate compounds, curing catalysts, curing accelerators, surfactants, fillers, dispersants, photosensitizers, etc. It can be mentioned. The blend ratio of the other components can be appropriately selected according to each compound, as long as the effects of the present invention are not impaired.

The solid content concentration in the liquid crystal aligning agent (the ratio of the total mass of components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc. It is in the range of 1 to 10% by mass. When the solid content concentration is less than 1% by mass, the film thickness of the coating film is 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 to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases and the coating property decreases. Tend to

«Liquid crystal element»
The liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. Liquid crystal elements can be effectively applied to various applications. For example, clocks, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions It can be used as various display devices such as information display, light control film, retardation film and the like. When used as a liquid crystal display element, the operation mode of the liquid crystal is not particularly limited. For example, TN type, STN type, vertical alignment type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB It can be applied to various modes such as (Optically Compensated Bend) type.

The liquid crystal element can be manufactured, for example, by the following steps. Here, the case of producing a retardation film and a liquid crystal display element will be described as an example.
[Step 1: Formation of a Coating]
First, a liquid crystal aligning agent is applied on a substrate, and then a coating film is formed on the substrate by heating the coated surface as required. A transparent substrate can be preferably used as the substrate. Specifically, for example, glass substrates such as float glass and soda glass; cellulose acylate (cellulose acetate and the like such as triacetyl cellulose (TAC)), polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polysulfone, polyether sulfone, Examples thereof include resin films of polyamide, polyimide, poly (meth) acrylate, polymethyl methacrylate, polycarbonate, cyclic polyolefin and the like. In particular, the liquid crystal aligning agent of the present disclosure can be preferably applied as a liquid crystal aligning agent for coating a resin film. In addition, conventionally well-known pretreatments, such as a saponification process, may be performed with respect to the base material which apply | coats a liquid crystal aligning agent in order to make adhesiveness of a base-material surface and a liquid crystal aligning film favorable.

In the case of a liquid crystal display element, at least one of the pair of substrates uses a substrate provided with a transparent conductive film on one side of the substrate. As the transparent conductive film, a NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ), etc. can be used. In the case of producing a TN type, STN type or vertical alignment type liquid crystal display element, two substrates provided with a patterned transparent conductive film are used. In the case of manufacturing a IPS type or FFS type lateral electric field liquid crystal display element, a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb shape is not provided, and the electrode is not provided. The opposite substrate is used. For example, a film made of a metal such as chromium can be used as the metal film.

The coating method of the liquid crystal aligning agent to a base material can employ | adopt the suitable coating method according to the kind of base material. Specific examples include roll coater method, spinner method, inkjet printing method, offset printing method, flexographic printing method, bar coater method, extrusion die method, direct gravure coater method, chamber doctor coater method, offset gravure coater method, impregnation The coater method, the MB coater method and the like can be mentioned. After the application of the liquid crystal alignment agent, it is preferable to heat (bak) the application surface. The heating temperature at this time is set according to the substrate, but when the substrate is a resin film, it is preferably 150 ° C. or less, more preferably 40 to 150 ° C., still more preferably 80 to 140 ° C. It is. The heating time is preferably 0.1 to 15 minutes, more preferably 1 to 10 minutes. The heating of the coated surface may be a plurality of heat treatments by prebaking and postbaking. Thus, a coating film to be a liquid crystal alignment film is formed on the substrate.

The thickness of the coating film formed on the substrate is preferably 1 nm to 1 μm, more preferably 5 nm to 0.5 μm. Here, when forming a liquid crystal alignment film on a substrate, in order to enhance the alignment of the liquid crystal by the liquid crystal alignment film and the adhesion between the liquid crystal alignment film and the substrate (in particular, a resin film substrate) The film thickness of the liquid crystal alignment film may be relatively thick (for example, 0.2 μm or 0.3 μm or more). On the other hand, when the film thickness of the liquid crystal alignment film is increased, the solvent tends to remain in the alignment film, and the influence of the remaining solvent causes coating unevenness on the surface of the alignment film, or the substrate on which the alignment film is formed is overlapped. In some cases, offset may occur in which the polymer component and the residual solvent in the alignment film are transferred to the substrate side. In this case, the orientation of the liquid crystal of the display element to be obtained is likely to be reduced, and the product yield is likely to be reduced. One possible means to reduce the residual solvent in the alignment film is to increase the heating temperature at the time of film formation, but if heating at high temperature is required, the application of the resin film as a substrate is limited. It will be done. In this respect, the liquid crystal aligning agent of the present disclosure can suppress the occurrence of the above-mentioned inconvenience even when the film thickness of the liquid crystal aligning film is increased to 0.3 μm or more, and is suitable as a liquid crystal aligning agent for a resin film.

[Step 2: Alignment Treatment]
Then, the process (alignment process) which provides liquid crystal aligning ability to the coating film formed at the said process 1 is implemented. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. As the alignment treatment, for example, a rubbing treatment for imparting a liquid crystal alignment ability to the coating film by rubbing the coating film in a fixed direction with a roll wound with a cloth made of fibers such as nylon, rayon or cotton, a substrate coated with a liquid crystal aligning agent The surface may be irradiated with light to give a coating film with a liquid crystal alignment ability, or the like. Photo-alignment treatment is preferably applied in that it can suppress the occurrence of display defects and yield reduction due to the generation of dust and static electricity, and can uniformly impart the liquid crystal alignment ability to the organic thin film formed on the substrate. can do. In addition, when manufacturing a liquid crystal display element of a vertical alignment type, although the coating film formed at the said process 1 can be used as a liquid crystal aligning film as it is, you may give an orientation process with respect to this coating film.

In the light alignment treatment, examples of light to be irradiated include ultraviolet light including light having a wavelength of 150 to 800 nm, visible light and the like. Among these, ultraviolet light containing light of a wavelength of 300 to 400 nm is preferable. The irradiation light may be polarized or non-polarized. It is preferable to use light including linear polarization as the polarization. When the light to be used is polarized light, the light may be irradiated from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. In the case of irradiating non-polarized light, it is necessary to carry out from a direction oblique to the substrate surface.

Examples of the light source to be used include a low pressure mercury lamp, a high pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, a mercury-xenon lamp (Hg-Xe lamp) and the like. Polarization can be obtained by means of using these light sources, for example, in combination with filters, diffraction gratings and the like. The dose of light is ^preferably set to 0.1mJ / cm 2 ~ 1,000mJ / cm 2, and more preferably in the 1 ~ 500mJ / cm ^2.

[Step 3-1: Formation of Optical Anisotropic Film]
When manufacturing a retardation film as a liquid crystal element, next, a polymeric liquid crystal is apply | coated and hardened on the coating film (liquid crystal aligning film) after light irradiation. Thereby, an optically anisotropic film which is an organic thin film having an optical compensation function is formed on the surface of the liquid crystal alignment film. The polymerizable liquid crystal used herein is a liquid crystal compound which is polymerized by the treatment of at least one of heating and light irradiation. As a polymeric group which a polymeric liquid crystal has, a (meth) acryloyl group, a vinyl group, a vinylphenyl group, an allyl group etc. are mentioned, for example, A (meth) acryloyl group is preferable.

As the polymerizable liquid crystal, conventionally known ones can be used. Specifically, for example, non-patent document 1 (“UV curable liquid crystal and its application”, liquid crystal, Volume 3, No. 1 (1999), pp 34 Mention may be made of the nematic liquid crystals described in -42). The liquid crystal may be cholesteric liquid crystal, discotic liquid crystal, twisted nematic alignment liquid crystal to which a chiral agent is added, or the like. The polymerizable liquid crystal may be a mixture of a plurality of liquid crystal compounds, and may be a composition further containing a known polymerization initiator, an appropriate solvent, a polymerizable monomer, a surfactant and the like. In order to apply the polymerizable liquid crystal on the formed liquid crystal alignment film, an appropriate application method such as a bar coater method, a roll coater method, a spinner method, a printing method, an inkjet method, or the like can be employed.

Subsequently, the coating film of the polymerizable liquid crystal formed as described above is cured by applying at least one treatment selected from heating and light irradiation to cure the coating film and thereby the liquid crystal layer (optical Formation of the It is preferable to perform these treatments in a superimposed manner since good orientation can be obtained. The heating temperature of a coating film is suitably selected by the kind of polymeric liquid crystal to be used. For example, when using RMS03-013C manufactured by Merck, it is preferable to heat at a temperature in the range of 40 to 80.degree. The heating time is preferably 0.5 to 5 minutes. As the irradiation light for the coating film, non-polarized ultraviolet light having a wavelength in the range of 200 to 500 nm can be preferably used. The irradiation dose of light is preferably 50 to 10,000 mJ / cm ^2, and more preferably 100 to 5,000 mJ / cm ² . The coating film may be irradiated with polarized radiation only once from a predetermined polarization direction, or radiation different in polarization direction (incident direction) may be irradiated to the coating multiple times.

The thickness of the optical anisotropic film to be formed is appropriately set according to the desired optical characteristics. For example, in the case of producing a half-wave plate in visible light with a wavelength of 540 nm as the retardation film, a thickness is selected such that the retardation of the optically anisotropic film as the retardation film is 240 to 300 nm. In the case of a quarter wavelength plate, the thickness is selected such that the phase difference is 120 to 150 nm. The thickness of the optically anisotropic film from which the desired retardation is obtained varies depending on the optical properties of the polymerizable liquid crystal used. For example, when using RMS03-013C manufactured by Merck, the thickness for producing a quarter-wave plate is in the range of 0.6 to 1.5 μm.

As a method of producing a retardation film, a roll-to-roll system may be adopted because it can be easily produced on an industrial scale. In this method, a resin film is unrolled from a roll of a long resin film, and a liquid crystal alignment film is formed on the unrolled film, and a polymerizable liquid crystal is coated on the liquid crystal alignment film. The process of curing and, if necessary, the process of laminating a protective film is performed in a continuous process, and the film after these processes is recovered again as a wound body. In the roll-to-roll method, while moving from the step of forming a liquid crystal alignment film to the step of applying and curing a polymerizable liquid crystal, the resin film with an alignment film is wound once, and then the next step (polymerizability The liquid crystal may be applied and cured. At this time, if there is back-off where the residual solvent or polymer component in the liquid crystal alignment film moves to the substrate side, or if there is not enough solvent removal in the alignment film even if there is no back-off, the polymerizable liquid crystal When the film is unwound for coating and curing treatment, peeling of the liquid crystal alignment film from the substrate is likely to occur. In this respect, according to the liquid crystal aligning agent of the present disclosure, the amount of the solvent remaining in the alignment film can be reduced, which is preferable in that it is difficult to cause offset to the base material.

[Step 3-2: Construction of Liquid Crystal Cell]
When a liquid crystal display element is manufactured as a liquid crystal element, two substrates on which a liquid crystal alignment film is formed as described above are prepared, and a liquid crystal cell is formed by disposing a liquid crystal between two opposed substrates. Manufacture. Specifically, the peripheral portions of a pair of substrates are pasted together with a sealing agent, liquid crystal is injected and filled in the cell gap partitioned by the substrate surface and the sealing agent, and then the injection holes are sealed; A sealing agent is applied to the periphery of the liquid crystal alignment film side of the base material, and liquid crystal is further dropped to a predetermined number of places on the liquid crystal alignment film surface, and then the other base material is bonded so that the liquid crystal alignment film faces. At the same time, the liquid crystal is spread over the entire surface of the substrate and then the sealing agent is cured (ODF method). As a sealing agent, the epoxy resin etc. which contain an aluminum oxide ball as a hardening agent and a spacer, for example are mentioned. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, among which nematic liquid crystals are preferred. In addition, cholesteric liquid crystals, chiral agents, ferroelectric liquid crystals, and the like may be added to liquid crystals for use.

Subsequently, if necessary, a polarizing plate is attached to the outer surface of the liquid crystal cell to obtain a liquid crystal display element. Examples of the polarizing plate include a polarizing plate in which a polarizing film called “H film” obtained by absorbing iodine while stretching and orienting polyvinyl alcohol is sandwiched by a cellulose acetate protective film or a polarizing plate consisting of the H film itself.

Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited by these examples.

In the following examples, the weight average molecular weight Mw, the number average molecular weight Mn and the epoxy equivalent of the polymer, and the solution viscosity of the polymer solution were measured by the following methods. The necessary amounts of the raw material compounds and the polymers used in the following examples were secured by repeating the synthesis on the synthesis scale shown in the following synthesis examples as necessary.

[Weight average molecular weight Mw and number average molecular weight Mn of polymer]
Mw and Mn are polystyrene conversion values measured by GPC under the following conditions.
Column: Tosoh Corp. TSKgel GRC XLII
Solvent: Tetrahydrofuran Temperature: 40 ° C.
Pressure: 68 kgf / cm ²
[Epoxy equivalent]
The epoxy equivalent was measured by the hydrochloric acid-methyl ethyl ketone method described in JIS C 2105.
Solution viscosity of polymer solution
The solution viscosity (mPa · s) of the polymer solution was measured at 25 ° C. using an E-type rotational viscometer.

<Synthesis of Polymer and Compound>
Synthesis Example 1-1 Synthesis of Epoxy Group-Containing Polyorganosiloxane (EPS-1)
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 100 g of propylene glycol monomethyl ether acetate, 100 g of deionized water, 10.0 g of triethylamine, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane 68.1 g, 31.9 g of methacryloxyoctyl trimethoxysilane, and 0.074 g of pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) were charged and mixed at room temperature. The reaction was then allowed to reflux at 60 ° C. for 6 hours. After completion of the reaction, the organic layer is taken out and washed with a 0.2% by mass aqueous ammonium nitrate solution until the water after washing becomes neutral, and then the solvent and water are distilled off under reduced pressure to obtain an epoxy group-containing polyorganosiloxane (EPS-1) was obtained as a viscous transparent liquid. The epoxy group-containing polyorganosiloxane was subjected to ¹ H-NMR analysis, and a peak based on the oxiranyl group was obtained around chemical shift (δ) = 3.2 ppm, and a side reaction of the epoxy group occurred during the reaction. It was confirmed that there was not. The epoxy group-containing polyorganosiloxane had a weight average molecular weight Mw of 2,200 and an epoxy equivalent of 186 g / mol.

Synthesis Example 1-2 Synthesis of Polyorganosiloxane (PS-1)
In a 100 mL three-necked flask, 10.1 g of epoxy group-containing polyorganosiloxane (EPS-1) obtained in Synthesis Example 1-1, 1.3 g of 4- (4-n-pentylcyclohexyl) benzoic acid, propylene glycol monomethyl ether acetate 17 g and 0.3 g of tetrabutylammonium bromide were charged, and stirred at 90 ° C. for 12 hours. After completion of the reaction, the reaction solution was diluted with 0.75 equivalent (mass) of cyclohexane and washed five times with water. This solution was concentrated, and the operation of diluting with propylene glycol monomethyl ether acetate (PGMEA) was repeated twice to obtain a solution containing polyorganosiloxane (PS-1) having a vertical alignment group. The weight average molecular weight Mw of this polyorganosiloxane (PS-1) was 8,000.

Synthesis Example 2-A Synthesis of Cinnamic Acid Derivative (mc-1)
In a 500 mL three-necked flask equipped with a condenser, 19.2 g of 1-bromo-4-cyclohexylbenzene, 0.18 g of palladium acetate, 0.98 g of tris (2-tolyl) phosphine, 32.4 g of triethylamine, and 135 mL of dimethylacetamide Added and mixed. Next, 7 g of acrylic acid was added to the mixed solution with a syringe and stirred. The mixture solution was further stirred while heating at 120 ° C. for 3 hours. After completion of the reaction was confirmed by thin layer chromatography (TLC), the reaction solution was cooled to room temperature. After filtering off the precipitate, the filtrate was poured into 300 mL of 1 N aqueous hydrochloric acid solution, and the precipitate was recovered. These precipitates were recrystallized with a 1: 1 (mass ratio) solution of ethyl acetate and hexane to obtain 10.2 g of a cinnamic acid derivative represented by the following formula (mc-1).

Synthesis Example 2-1 Synthesis of Epoxy Group-Containing Polyorganosiloxane (EPS-2)
In a reaction vessel equipped with a stirrer, thermometer, dropping funnel and reflux condenser, 100.0 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 500 g of methyl isobutyl ketone and 10.0 g of triethylamine are charged, and room temperature Mixed. Next, 100 g of deionized water was added dropwise over 30 minutes from the dropping funnel, and then reacted at 80 ° C. for 6 hours while mixing under reflux. After completion of the reaction, the organic layer is taken out and washed with a 0.2 wt% aqueous ammonium nitrate solution until the water after washing becomes neutral, and then the solvent and water are distilled off under reduced pressure to obtain an epoxy group-containing polyorganosiloxane (EPS-2) was obtained as a viscous transparent liquid.
The epoxy group-containing polyorganosiloxane was subjected to ¹ H-NMR analysis, and a peak based on the oxiranyl group was obtained around chemical shift (δ) = 3.2 ppm, and a side reaction of the epoxy group occurred during the reaction. It was confirmed that there was not. The epoxy group-containing polyorganosiloxane had a weight average molecular weight Mw of 2,200 and an epoxy equivalent of 186 g / mol.

Synthesis Example 2-2 Synthesis of Photoalignable Group-Containing Polyorganosiloxane (PS-2)
In a 100 mL three-necked flask, 10.1 g of epoxy group-containing polyorganosiloxane (EPS-2) obtained in Synthesis Example 2-1, acrylic group-containing carboxylic acid (Toagosei Co., Ltd., trade name "ALONIX M-5300", acrylic Acid ω-carboxypolycaprolactone (degree of polymerization n ≒ 2) 0.5 g, butyl acetate 20 g, cinnamic acid derivative (mc-1) obtained in Synthesis Example 2-A 1.5 g, and tetrabutyl ammonium bromide 0.3 g Were stirred at 90.degree. C. for 12 hours. After completion of the reaction, the reaction solution was diluted with an equal amount (mass) of propylene glycol monomethyl ether acetate and washed three times with water. This solution was concentrated, and the operation of diluting with propylene glycol monomethyl ether acetate was repeated twice to finally obtain a solution containing a polyorganosiloxane (PS-2) having a photoalignable group. The weight average molecular weight Mw of this polyorganosiloxane (PS-2) was 9,000.

Synthesis Example 3-1 Synthesis of Epoxy-Containing Polymethacrylate (AP-1)
In a flask equipped with a condenser and a stirrer, 1 part by mass of 2,2′-azobis (isobutyronitrile) as a polymerization initiator and 180 parts by mass of propylene glycol monomethyl ether acetate as a solvent were charged. To this, 50 parts by mass of 3,4-epoxycyclohexylmethyl methacrylate and 50 parts by mass of (3-ethyl oxetan-3-yl) methyl methacrylate were added, and the inside of the flask was replaced with nitrogen, and then stirring was gently started. By raising the solution temperature to 80 ° C. and maintaining this temperature for 5 hours, a polymer solution containing 32.9% by mass of polymethacrylate having an epoxy group was obtained. The number average molecular weight Mn of the obtained epoxy-containing polymethacrylate was 16,000.

Synthesis Example 4-1 Synthesis of Photoalignable Group-Containing Polyamic Acid (PAA-1)
2.24 g (0.01 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic acid dianhydride, and 2.54 g (0.01 mol) of a compound represented by the following formula (8) as diamine Mol) was dissolved in 27.1 g of N-methyl-2-pyrrolidone (NMP) and reacted at 40 ° C. for 3 hours to obtain 31.8 g of a solution containing 15% by mass of polyamic acid (PAA-1) . The solution viscosity of this polyamic acid solution was 68 mPa · s.

Synthesis Example 5-A: Synthesis of Methacrylate (9)
4 '-(6-bromohexyloxy) biphenyl-4-ol was synthesized by heating 4,4'-biphenyldiol and 1,6-dibromohexane under alkaline conditions. The product was reacted with lithium methacrylate to give 2- (4'-hydroxybiphenyl-4-yloxy) hexyloxy methacrylate. Subsequently, 4-methoxycinnamoyl chloride was added under basic conditions to synthesize a compound represented by the following formula (9) (methacrylic acid ester (9)).

Synthesis Example 5-B: Synthesis of Methacrylate (10)
4- (6-hydroxyhexyloxy) cinnamic acid was synthesized by heating 4-hydroxycinnamic acid and 1-hydroxy-6-hexanol under alkaline conditions. This product was reacted with methacrylic acid chloride under basic conditions to obtain a compound (methacrylic acid ester (10)) represented by the following formula (10).

Synthesis Example 5-C: Synthesis of Methacrylate (11)
4- (6-hydroxyhexyloxy) iodophenol was synthesized by heating 4-iodophenol and 6-chloro-1-hexanol under alkaline conditions. This product is reacted with 2-methyl-3-butyn-2-ol, and then heated under alkaline conditions to give 4- (6-hydroxyhexyloxy) ethynylbenzene (which will be referred to as Compound A). Obtained. Further, in another route, 4-methoxycinnamic acid chloride was reacted with 4-iodophenol to synthesize 4-iodophenyl-3- (4-methoxyphenyl) acrylate (referred to as compound B). Subsequently, compound A and compound B were reacted under basic conditions to obtain a compound (methacrylic acid ester (11)) represented by the following formula (11).

Synthesis Example 5-1 Synthesis of Liquid Crystalline Polymethacrylate (LCP-1)
A polymer solution was obtained by dissolving methacrylic acid ester (9) in tetrahydrofuran, adding azobisisobutyronitrile (AIBN) as a reaction initiator and polymerizing. The polymer solution was added dropwise to diethyl ether (5000 ml) and the resulting precipitate was filtered. The precipitate was washed with diethyl ether and dried under reduced pressure in an oven at 40 ° C. to obtain liquid crystalline polymethacrylate (LCP-1) as a powder. The number average molecular weight of the obtained polymethacrylate (LCP-1) was 46,000, and the weight average molecular weight was 119,600. This polymethacrylate (LCP-1) exhibited liquid crystallinity in the temperature range of 116 ° C. to 315 ° C.

Synthesis Example 5-2 Synthesis of Liquid Crystalline Polymethacrylate (LCP-2)
A polymethacrylate (LCP-2) was obtained by the same operation as in Synthesis Example 5-1 except that a methacrylic acid ester (10) was used instead of the methacrylic acid ester (9). The number average molecular weight of the obtained polymethacrylate (LCP-2) was 46,000, and the weight average molecular weight was 119,600. This polymethacrylate (LCP-2) exhibited liquid crystallinity in the temperature range of 135 ° C. to 187 ° C.
Synthesis Example 5-3 Synthesis of Liquid Crystalline Polymethacrylate (LCP-3)
A polymethacrylate (LCP-3) was obtained by the same procedure as in Synthesis Example 5-1 except that a methacrylic acid ester (11) was used instead of the methacrylic acid ester (9). The number average molecular weight of the obtained polymethacrylate (LCP-3) was 46,000, and the weight average molecular weight was 119,600. This polymethacrylate (LCP-3) exhibited liquid crystallinity in the temperature range of 66 ° C to 320 ° C.

<Preparation and Evaluation of Liquid Crystal Alignment Film>
Example 1
1. Preparation of Liquid Crystal Alignment Agent In a solution containing polymethacrylate (AP-1) as a polymer component, polyorganosiloxane (PS-1) was added to polymethacrylate (AP-1): polyorganosiloxane (PS-1) = 95. Further, methyl 3-methoxypropionate (MMP), propylene glycol monomethyl ether acetate (PGMEA), and propylene glycol monomethyl ether (PGME) are added as solvents, and sufficiently stirred, It was set as the solution whose solvent composition is MMP: PGMEA: PGME = 10: 40: 50 (mass ratio) and solid content concentration 4.0 mass%. The solution was filtered using a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent (AL-1).

2. Evaluation of coatability As a sample for evaluation, the above 1. The liquid crystal aligning agent (AL-1) prepared in the above was coated on a PET film with a bar coater and dried at 120 ° C. for 2 minutes to form a liquid crystal alignment film. The coating property (coating nonuniformity) of the liquid crystal aligning agent was evaluated by observing the nonuniformity of the surface of this liquid crystal aligning film under a microscope. As a sample for evaluation, the film thickness of the liquid crystal aligning film after drying produced two types, 0.1 micrometer and 0.3 micrometer. The thicker the film thickness, the more easily unevenness occurs on the surface of the liquid crystal alignment film. The evaluation was "very good (◎)" when no unevenness was observed on the surface of the coating, "good (○)" when unevenness was slightly observed on the surface of the coating, on the surface of the coating It was regarded as "Poor (△)" when a slight unevenness was observed, and "Defect (x)" when a large number of unevenness was observed on the surface of the coating. As a result, in this example, the evaluation was "very good" when the film thickness is 0.1 μm, and "good" when the film thickness is 0.3 μm.

3. Evaluation of Settling to Base Material As a sample for evaluation, the above 1. The liquid crystal aligning agent (AL-1) prepared in the above was coated on a PET film with a bar coater and dried at 120 ° C. for 2 minutes to form a liquid crystal alignment film having a film thickness of 0.1 μm. Next, the PET film (B) was superposed on the liquid crystal alignment film surface (A), and a state of applying a load of 40 g / cm ² was maintained at 80 ° C. for 30 minutes, and then cooled to room temperature while being superposed. Thereafter, the PET film (B) was peeled off from the liquid crystal alignment film surface (A), and it was visually observed whether the polymer component and the residual solvent of the liquid crystal alignment film were offset to the PET film (B). When the polymer component and the residual solvent of the liquid crystal alignment film are transferred to the PET film (B), it is observed that the transferred portion is cloudy. The evaluation was "very good (◎)" when no offset was observed on the PET film (B), "good (○)" when offset was observed slightly, and the offset was slightly The case where it observed was made into "good ((triangle | delta))", and the case where the offset was entirely observed was made into "defect (x)." Moreover, evaluation was performed in the same manner as described above except that the load was changed from 40 g / cm ² to 80 g / cm ² . As a result, in this example, when the load was 40 g / cm ² and when it was 80 g / cm ² , it was evaluated as “very good”.

[Examples 2 to 23 and Comparative Examples 1 to 4]
The same operation as in Example 1 is carried out except that the composition of the liquid crystal aligning agent is changed as described in Tables 1 and 2 below, and liquid crystal aligning agents (AL-2) to (AL-23), (BL-) 1) to (BL-4) were prepared respectively. Further, the same as Example 1 except that liquid crystal aligning agents (AL-2) to (AL-23) and (BL-1) to (BL-4) were used instead of the liquid crystal aligning agent (AL-1). We made various evaluations. The results are shown in Table 3 below.

In Tables 1 and 2, the numerical values in the parenthesis of the polymer column show the blending ratio (parts by mass) of each polymer to the total 100 parts by mass of the polymer component used for the preparation of the liquid crystal aligning agent. The numerical values in the solvent column indicate the blending ratio (parts by mass) of each solvent with respect to a total of 100 parts by mass of the solvent components used for preparing the liquid crystal aligning agent. "-" Means that the compound was not used. Abbreviations of the compounds are as follows.
<Solvent>
MMP: methyl 3-methoxypropionate EEP: ethyl 3-ethoxypropionate MBA: 3-methoxybutyl acetate PGMPE: propylene glycol methyl propyl ether PGMBE: propylene glycol methyl butyl ether CA: cyclohexyl acetate CP: cyclohexyl propionate NMP: N-methyl -2-pyrrolidone GBL: gamma-butyrolactone NEP: N-ethyl-2-pyrrolidone DMI: 1,3-dimethyl-2-imidazolidinone PGMEA: propylene glycol monomethyl ether acetate PGME: propylene glycol monomethyl ether DEDG: diethylene glycol diethyl ether BC: Butyl cellosolve

As can be seen from Table 3, in Examples 1 to 23 using a liquid crystal aligning agent containing a solvent (A), the coatability and the releasability are evaluated as “very good”, “good” or “good”. , Both were in balance. Moreover, the coating property at the time of setting the film thickness of a liquid crystal aligning film to 0.3 micrometer was further improved by using (B) solvent together. On the other hand, among the comparative examples (A) containing no solvent, in the comparative examples 1 to 3, when the film thickness was 0.3 μm, the coating property was evaluated as “defective”. Moreover, in Comparative Examples 3 and 4, the reverse transferability was evaluated as "poor".

Claims (11)

1. Containing a polymer component and a solvent component,
   The solvent component is a liquid crystal aligning agent comprising 1 to 70% by mass of the following solvent (A) with respect to the total amount of the solvent component, and 0 to 40% by mass with respect to the following solvent (B). .
   (A) Solvent: a group consisting of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, a compound represented by the following formula (1), and a compound represented by the following formula (2) At least one compound selected from
   (B) Solvent: a compound having a boiling point of 200 ° C. or higher at atmospheric pressure and different from the solvent (A).
   

   

   (In the formula (1), R ¹ is an alkyl group having 1 to 4 carbon atoms.)
   

   

   (In formula (2), R ² is an alkyl group having 1 to 4 carbon atoms, R ³ is an alkyl group having 1 to 4 carbon atoms. N is 0 or 1.)
2. The solvent (B) is selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, gamma-butyrolactone, and a compound represented by the following formula (3) The liquid crystal aligning agent of Claim 1 which is at least 1 type chosen from the group which consists of.
   

   

   (In the formula (3), R ⁴ and R ⁵ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms which may have an ether bond, and R ⁴ and R ⁵ may combine with each other to form a ring structure, and R ⁶ is an alkyl group having 1 to 4 carbon atoms.
3. The polymer component contains at least one (P) polymer selected from the group consisting of polyamic acid, polyimide, polyamic acid ester, polyamide imide, poly (meth) acrylate, and polyorganosiloxane. Or 2. Liquid crystal aligning agent as described in 2.
4. The (P) polymer is at least one photosensitive structure selected from the group consisting of cinnamic acid structure, azobenzene structure, chalcone structure, stilbene structure, diphenylacetylene structure, (meth) acryloyl group, vinyl group, and phenylbenzoate structure. The liquid crystal aligning agent of Claim 3 which has.
5. The liquid crystal aligning agent according to claim 3 or 4 in which said (P) polymer has a partial structure which expresses liquid crystallinity in a predetermined temperature range in a side chain.
6. Cellulose acylate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polysulfone, polyether sulfone, polyamide, polyimide, poly (meth) acrylate, polymethyl methacrylate, polycarbonate, and at least one resin selected from cyclic polyolefins The liquid crystal aligning agent according to any one of claims 1 to 5, which is for coating on a substrate.
7. At least one member selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons, which further comprises (C) a solvent different from the above-mentioned (A) solvent, Item 7. The liquid crystal aligning agent according to any one of items 1 to 6.
8. The liquid crystal aligning agent of Claim 7 whose content rate of the said (C) solvent is 20 mass% or more with respect to the total amount of the said solvent component.
9. A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 8.
10. The liquid crystal element which comprises the liquid crystal aligning film of Claim 9.
11. A method for producing a liquid crystal alignment film, which comprises applying the liquid crystal aligning agent according to any one of claims 1 to 8 on a substrate and heating it at 150 ° C or less to form a coating.