JP6672821B2 - Method for producing liquid crystal alignment agent and liquid crystal alignment film - Google Patents

Description

The present invention relates to the production how the liquid crystal alignment agent and liquid crystal alignment film.

  2. Description of the Related Art Conventionally, as a liquid crystal element, various driving methods having different electrode structures and physical properties of liquid crystal molecules to be used have been developed. For example, TN type, STN type, VA type, in-plane switching type (IPS type). , FFS type, optical compensation bent type (OCB type) and other various liquid crystal elements are known. These liquid crystal elements have a liquid crystal alignment film for aligning liquid crystal molecules. As a material for the liquid crystal alignment film, polyamic acid, polyimide, or the like is used because of its excellent properties such as heat resistance, mechanical strength, and affinity for liquid crystal.

  In the liquid crystal alignment agent, a polymer component is dissolved in a solvent, and a liquid crystal alignment film is formed by applying the liquid crystal alignment agent to a substrate and heating the substrate. Here, as a solvent for the liquid crystal aligning agent, an organic solvent having high polymer solubility, for example, an aprotic polar solvent such as N-methyl-2-pyrrolidone or γ-butyrolactone is generally used. In addition, in order to improve the applicability (printability) of the liquid crystal aligning agent when applying the liquid crystal aligning agent to the substrate, an organic solvent having a relatively low surface tension such as butyl cellosolve is used together with the aprotic polar solvent. They are used in combination (for example, see Patent Documents 1 and 2).

  As a method of applying the liquid crystal aligning agent to the substrate, various methods such as a spin coating method, an offset printing method, and an inkjet method are applied. For example, the offset printing method is generally performed using a transfer printing apparatus that applies a liquid crystal aligning agent to a printing plate made of a resin such as APR (registered trademark) and transfers the liquid crystal aligning agent onto a substrate using the printing plate (for example, Patent Document 3).

JP 2010-97188 A JP 2010-156934 A JP 2001-343649 A

  Butyl cellosolve, which is generally used for the purpose of improving the coating property of the liquid crystal alignment agent, tends to swell the APR resin. Therefore, when a liquid crystal aligning agent containing butyl cellosolve is applied to a substrate by offset printing, there is a concern that the printing plate swells due to repeated application to the printing plate, thereby reducing printability. Further, as a solvent component of the liquid crystal aligning agent, it is required that a polymer hardly precipitates on a printing machine even when printing is performed continuously and that printability (continuous printability) is good.

  The present invention has been made in view of the above problems, and has as its object to provide a liquid crystal aligning agent that hardly swells a printing plate and has good printability.

  The present inventors have conducted intensive studies to achieve the above-described problems of the related art, and as a result, have found that the above-mentioned problems can be solved by using a specific organic solvent in combination as a solvent. It was completed. Specifically, the present invention provides the following liquid crystal alignment agent, liquid crystal alignment film, a method for producing the same, and a liquid crystal element.

  In one aspect, the present invention provides at least one polymer (A) selected from the group consisting of a polyamic acid, a polyamic acid ester, a polyimide, and a polyorganosiloxane; a compound represented by the following formula (1); A first solvent which is at least one selected from the group consisting of a compound represented by 2), a compound represented by the following formula (3), and a compound represented by the following formula (4), and a surface tension of 30 dyn / and a second solvent having a diameter of less than 2 cm.

（式（４）中、Ｒ^１及びＲ^２は、それぞれ独立にメチル基又はエチル基である。）

(In the formula (4), R ¹ and R ² are each independently a methyl group or an ethyl group.)

  By using a mixed solvent containing the first solvent and the second solvent as a solvent component of the liquid crystal aligning agent, a liquid crystal aligning agent that does not easily cause the printing plate to swell can be obtained. Further, even when printing is performed continuously, the polymer hardly precipitates on the printing press, and the printability can be improved.

  The second solvent is a compound represented by the following formula (5), a compound represented by the following formula (6), a compound represented by the following formula (7), and a compound represented by the following formula (8) It is preferably at least one selected from the group consisting of: By using at least one of these as the second solvent, a higher improvement effect can be obtained in the suppression of swelling of the printing plate and in the continuous printability.

（式（５）中、Ｒ^５及びＲ^７は、それぞれ独立に炭素数１〜３の１価の炭化水素基であり、Ｒ^６は、炭素数２〜５のアルカンジイル基である。）

(In the formula (5), R ⁵ and R ⁷ are each independently a monovalent hydrocarbon group having 1 to 3 carbon atoms, and R ⁶ is an alkanediyl group having 2 to 5 carbon atoms.)

（式（６）中、Ｒ^８は、炭素数３〜５の直鎖状若しくは分岐状のアルキル基の炭素−炭素結合間に「−Ｏ−」を１つ有する１価の基、炭素数３〜５の直鎖状若しくは分岐状のアルキル基の少なくとも１つの水素原子がヒドロキシル基で置換されてなる１価の基、又は炭素数３〜５の分岐状のアルキル基である。）

(In the formula (6), R ⁸ is a monovalent group having one “—O—” between carbon-carbon bonds of a linear or branched alkyl group having 3 to 5 carbon atoms; A monovalent group in which at least one hydrogen atom of a linear or branched alkyl group having 5 to 5 carbon atoms is substituted with a hydroxyl group, or a branched alkyl group having 3 to 5 carbon atoms.)

（式（７）中、Ｘ^１は、−Ｃ（ＯＨ）Ｒ^ａ−（但し、Ｒ^ａは炭素数１又は２のアルキル基である。）、−ＣＯ−又は−ＣＯＯ−＊（但し、＊はＲ^９との結合手を示す。）であり、Ｒ^９は、炭素数１〜４のアルキル基である。）

(In the formula (7), X ¹ represents —C (OH) R ^a — (where ^Ra is an alkyl group having 1 or 2 carbon atoms), —CO— or —COO- * (* is a.) showing a bond to ^{R 9, R 9} is an alkyl group having 1 to 4 carbon atoms.)

（式（８）中、Ｒ^３は炭素数１〜６のアルキル基であり、Ｒ^４は炭素数２〜４のアルカンジイル基である。）

(In the formula (8), R ³ is an alkyl group having 1 to 6 carbon atoms, and R ⁴ is an alkanediyl group having 2 to ⁴ carbon atoms.)

  In another aspect, the present invention provides a liquid crystal alignment film formed by the liquid crystal alignment agent. In another aspect, a step of applying the liquid crystal alignment agent on a substrate to form a coating film, and a step of irradiating the coating film with light to form a liquid crystal alignment film, A manufacturing method is provided. Still another aspect provides a liquid crystal element including a liquid crystal alignment film formed of the liquid crystal alignment agent.

  Since the liquid crystal alignment film of the present invention is formed using the above liquid crystal alignment agent, a uniform coating film can be formed and the film quality is good. Further, when a liquid crystal element is manufactured using the liquid crystal alignment agent, printing defects can be reduced in the manufacturing process, and as a result, the yield of products can be improved.

  Hereinafter, each component contained in the liquid crystal aligning agent of the present invention, and other components that are arbitrarily added as necessary will be described.

  In addition, in this specification, a "hydrocarbon group" is meant to include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “chain hydrocarbon group” means a linear hydrocarbon group and a branched hydrocarbon group that are composed of only a chain structure without a cyclic structure in the main chain. However, it may be saturated or unsaturated. The “alicyclic hydrocarbon group” means a hydrocarbon group containing only an alicyclic hydrocarbon structure as a ring structure and not containing an aromatic ring structure. However, it is not necessary to be constituted only by the structure of the alicyclic hydrocarbon, but also includes those having a chain structure in part. “Aromatic hydrocarbon group” means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to include only an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic hydrocarbon structure. “Organic group” means a group containing a carbon atom, and may contain a hetero atom in the structure.

<Polymer (A)>
The liquid crystal alignment agent of the present invention contains at least one polymer (A) selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane.
[Polyamic acid]
The polyamic acid in the present invention can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine.

(Tetracarboxylic dianhydride)
Examples of the tetracarboxylic dianhydride used in the synthesis of the polyamic acid include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. Specific examples of these include aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride;
Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2- c] Furan-1,3-dione, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), 5- (2,5-dioxotetrahydro 3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, , 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, cyclohexanetetracarboxylic dianhydride and the like;
As the aromatic tetracarboxylic dianhydride, for example, pyromellitic dianhydride and the like can be mentioned; in addition, the tetracarboxylic dianhydride described in JP-A-2010-97188 can be used. In addition, tetracarboxylic dianhydride can be used individually by 1 type or in combination of 2 or more types.

  As the tetracarboxylic dianhydride used in the synthesis, an alicyclic compound is preferable in that the electric characteristics can be improved and the solubility of the polymer in a solvent including the following first solvent and second solvent can be higher. Preferably, it contains tetracarboxylic dianhydride. In addition, among alicyclic tetracarboxylic dianhydrides, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5 -Dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5 -Dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: It preferably contains at least one selected from the group consisting of 8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 2,3,5-tricarboxycyclopentylacetic acid dianhydride. Thing, 2, , 6,8-Tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,3- It is particularly preferred that it contains at least one selected from the group consisting of dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride.

  As the tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8- At least one selected from the group consisting of dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride When one kind is included, the total content of those compounds is preferably 10 mol% or more, preferably 20 to 100 mol%, based on the total amount of tetracarboxylic dianhydride used for the synthesis of the polyamic acid. Is more preferable.

(Diamine)
Examples of the diamine used in the synthesis of the polyamic acid include an aliphatic diamine, an alicyclic diamine, an aromatic diamine, and a diaminoorganosiloxane. Specific examples of these diamines include aliphatic diamines such as metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and 1,3-bis (aminomethyl) cyclohexane. ;
Examples of the alicyclic diamine include 1,4-diaminocyclohexane and 4,4′-methylenebis (cyclohexylamine);

（式（Ｄ−１）中、Ｘ^I及びＸ^IIは、それぞれ独立に、単結合、−Ｏ−、＊−ＣＯＯ−、＊−ＯＣＯ−又は＊−ＮＨ−ＣＯ−（但し、「＊」を付した結合手がジアミノフェニル基と結合する。）であり、Ｒ^Ｉ及びＲ^ＩＩは、それぞれ独立に、炭素数１〜３のアルカンジイル基であり、ａは０又は１であり、ｂは０〜２の整数であり、ｃは１〜２０の整数であり、ｎは０又は１であり、ｍは０又は１である。但し、ａ及びｂが同時に０になることはなく、Ｘ^Ｉが＊−ＮＨ−ＣＯ−の場合、ｎは０である。）
で表される化合物などを；
ジアミノオルガノシロキサンとして、例えば、１，３−ビス（３−アミノプロピル）−テトラメチルジシロキサンなどを、それぞれ挙げることができるほか、特開２０１０−９７１８８号公報に記載のジアミンを用いることができる。なお、これらのジアミンは、１種を単独で又は２種以上組み合わせて使用することができる。 Examples of the aromatic diamine include p-phenylenediamine, N- [4- (2-aminoethyl) phenyl] benzene-1,4-diamine, and N- [4- (aminomethyl) phenyl] benzene-1,4-diamine , 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl ) -4,4′-Diaminobiphenyl, 4,4′-diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [ 4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(P-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 2,6-diaminopyridine, 3,6-diaminocarbazole, N, N'-bis (4-aminophenyl ) -Benzidine, 1,4-bis- (4-aminophenyl) -piperazine, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-5-amine, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, 3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzene, Cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, 3,5-diamido Cholestenyl benzoate, lanostanyl 3,5-diaminobenzoate, 3,6-bis (4-aminobenzoyloxy) cholestan, 4- (4'-trifluoromethoxybenzoyloxy) cyclohexyl-3,5-diaminobenzoate, 1 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, 2,4-diamino-N, N-diallylaniline, 4-aminobenzylamine, and the following formula (D-1)

(In the formula (D-1), ^XI and ^XII are each independently a single bond, -O-, * -COO-, * -OCO- or * -NH-CO- (provided that "*" R ^I and R ^II are each independently an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, and b is 0. an ~ 2 integer, c is an integer of 1 to 20, n is 0 or 1, m is 0 or 1. However, it is not possible a and b are 0 at the same time, the ^{X I} In the case of * -NH-CO-, n is 0.)
A compound represented by;
Examples of the diaminoorganosiloxane include, for example, 1,3-bis (3-aminopropyl) -tetramethyldisiloxane, and the diamine described in JP-A-2010-97188 can be used. In addition, these diamines can be used individually by 1 type or in combination of 2 or more types.

Specific examples of the compound represented by the formula (D-1) include, for example, compounds represented by the following formulas (D-1-1) to (D-1-4).

  The diamine used in the synthesis of the polyamic acid preferably contains an aromatic diamine in an amount of 30 mol% or more, more preferably 50 mol% or more, and particularly preferably 80 mol% or more based on the total diamine.

（式（ｂ）中、Ｘ^２は、硫黄原子又は酸素原子である。「＊」はそれぞれ結合手を示す。但し、２つの「＊」のうち少なくとも一つは芳香環に結合している。）
で表される部分構造を基本骨格として含有する構造、等が挙げられる。 When imparting liquid crystal alignment ability to a coating film by irradiating light to the coating film formed by the liquid crystal alignment agent, a part or all of the polymer (A) may be used as a polymer having a photo alignment structure. Good. Here, the photo-alignment structure is a concept including both the photo-alignment group and the decomposable photo-alignment portion. Specifically, as the photo-alignment structure, structures derived from various compounds exhibiting photo-alignment by photo-isomerization, photo-dimerization, photo-decomposition, and the like can be employed, and include, for example, azobenzene or a derivative thereof as a basic skeleton. Azobenzene-containing group, cinnamic acid structure-containing group containing cinnamic acid or a derivative thereof as a basic skeleton, chalcone-containing group containing chalcone or a derivative thereof as a basic skeleton, benzophenone-containing group containing benzophenone or a derivative thereof as a basic skeleton, coumarin Or a coumarin-containing group containing a derivative thereof as a basic skeleton, a cyclobutane-containing structure containing cyclobutane or a derivative thereof as a basic skeleton, or a bicyclo [2.2 containing a bicyclo [2.2.2] octene or a derivative thereof as a basic skeleton. .2] octene-containing structure, the following formula (b)

(In the formula (b), X ² is a sulfur atom or an oxygen atom. “*” Represents a bond, provided that at least one of the two “*” s is bonded to an aromatic ring. )
And a structure containing the partial structure represented by as a basic skeleton.

（式（Ｒ１）〜式（Ｒ５）中、Ｒ^Ｉは、炭素数３〜１２のアルキル基又は炭素数３〜１２のフルオロアルキル基であり、ａは、１〜６の整数である。） When the polyamic acid as the polymer (A) has a photo-alignable group as a photo-alignable structure, it is preferably a polymer having a cinnamic acid structure from the viewpoint of high alignment ability. Such a polyamic acid can be obtained, for example, by polymerization using a diamine having a cinnamic acid structure represented by the following formulas (R1) to (R7) as a raw material.

(In the formula (R1) ~ formula (R5), ^{R I} is a fluoroalkyl group having 3 to 12 alkyl group carbon atoms or 3 to 12 carbon atoms, a is an integer from 1 to 6.)

（式（ｃ）中、Ａ^１は単結合又は２価の有機基であり、Ｂ^１は２価の有機基である。Ｒ^１０は置換基であり、ｎ１は０〜４の整数である。） When the polyamic acid as the polymer (A) has a degradable photo-alignment portion as a photo-alignment structure, preferred specific examples of the polymer (A) include a bicyclo [2.2.2] octene skeleton. , A polymer having a cyclobutane skeleton, a polymer having a partial structure derived from a compound represented by the following formula (c), a polymer having a structure represented by the above formula (b) in the main chain, and the like. Is mentioned.

(In the formula (c), A ¹ is a single bond or a divalent organic group, B ¹ is a divalent organic group, R ¹⁰ is a substituent, and n1 is an integer of 0 to 4. )

For example, when a polyamic acid having a decomposition type photo-alignment part is reacted with a diamine with a tetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride is used as at least a part of the tetracarboxylic dianhydride used in the reaction [1]. Anhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, or tetracarboxylic dianhydride having a structure represented by the above formula (b) [2] a method using a diamine represented by the above formula (c) or a diamine having a structure represented by the above formula (b) as at least a part of the diamine used in the reaction. be able to.
When synthesizing a polyamic acid having a photo-alignable structure, the proportion of the monomer having a photo-alignable structure used is, in terms of photoreactivity, the total of tetracarboxylic dianhydride and diamine used for synthesizing the polyamic acid. The amount is preferably 20 mol% or more, more preferably 30 to 80 mol%, based on the amount.

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

The synthesis reaction of the polyamic acid is preferably performed in an organic solvent. The reaction temperature at this time is preferably from -20C to 150C, and the reaction time is preferably from 0.1 to 24 hours.
Examples of the organic solvent used in the reaction include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like. Particularly preferred organic solvents include compounds represented by the above formulas (1) to (4), N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, γ -Using at least one selected from the group consisting of butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol and halogenated phenol as a solvent, or one or more of these and another organic solvent (For example, butyl cellosolve, diethylene glycol diethyl ether, etc.) is preferably used in the above range. The amount (a) of the organic solvent used is such that the total amount (b) of the tetracarboxylic dianhydride and the diamine is 0.1 to 50% by weight based on the total amount (a + b) of the reaction solution. Is preferred.
As described above, a reaction solution obtained by dissolving the polyamic acid is obtained. This reaction solution may be directly used for preparing a liquid crystal aligning agent, or may be used for preparing a liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution.

[Polyimide]
The polyimide in the present invention can be obtained by dehydrating and cyclizing the polyamic acid synthesized as described above to imidize it. Polyimide may be a complete imidized product obtained by dehydrating and ring-closing all of the amic acid structure that the precursor polyamic acid had, and dehydrating and ring-closing only a part of the amic acid structure to form an amic acid structure and an imide. It may be a partially imidized compound having a ring structure. The imidation ratio of the polyimide in the present invention is preferably 30% or more, more preferably 40 to 99%, and still more preferably 50 to 99%. The imidation ratio is a percentage of the number of imide ring structures to the total number of amic acid structures and imide ring structures of the polyimide. Here, a part of the imide ring may be an isoimide ring.

The dehydration and ring closure of the polyamic acid is preferably carried out by a method of heating the polyamic acid or by dissolving the polyamic acid in an organic solvent and adding a dehydrating agent and a dehydration ring-closing catalyst to the solution and heating as necessary. . Of these, the latter method is preferred.
In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of a polyamic acid, an acid anhydride such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent used is preferably 0.01 to 20 mol per 1 mol of the amic acid structure of the polyamic 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 to 10 mol per 1 mol of the dehydrating agent used. Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used in the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, and the reaction time is preferably 1.0 to 120 hours.

  Thus, a reaction solution containing the polyimide is obtained. This reaction solution may be directly used for preparing a liquid crystal aligning agent, or may be used for preparing a liquid crystal aligning agent after removing a dehydrating agent and a dehydration ring-closing catalyst from the reaction solution. It may be used for preparing an alignment agent. These purification operations can be performed according to a known method. In addition, polyimide can also be obtained by imidizing a polyamic acid ester.

[Polyamic acid ester]
The polyamic acid ester in the present invention is, for example, [I] a method of reacting a polyamic acid obtained by the above synthesis reaction with an esterifying agent (for example, methanol, ethanol, N, N-dimethylformamide diethyl acetal, etc.), II] A tetracarboxylic diester and a diamine are treated with an appropriate dehydration catalyst (eg, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium) in an organic solvent. [III] tetracarboxylic diester dihalide and diamine in an organic solvent in a suitable base (eg, pyridine, triethylamine, sodium hydroxide, etc.). The reaction can be carried out in the presence.
The polyamic acid ester contained in the liquid crystal aligning agent may have only an amic acid ester structure, or may be a partially esterified product having both an amic acid structure and an amic acid ester structure. The reaction solution obtained by dissolving the polyamic acid ester may be directly used for preparing a liquid crystal aligning agent, or may be used for preparing a liquid crystal aligning agent after isolating the polyamic acid ester contained in the reaction solution. Good.

The polyamic acid, polyamic acid ester, and polyimide obtained as described above preferably have a solution viscosity of 10 to 800 mPa · s when used as a solution having a concentration of 10% by weight, and preferably have a solution viscosity of 15 to 500 mPa. More preferably, it has a solution viscosity of s. In addition, the solution viscosity (mPa · s) of the above polymer is based on a polymer solution having a concentration of 10% by weight prepared using a good solvent (eg, γ-butyrolactone, N-methyl-2-pyrrolidone) for the polymer. , Measured at 25 ° C. using an E-type rotational viscometer.
The polyamic acid, polyamic acid ester and polyimide contained in the liquid crystal aligning agent of the present invention preferably have a polystyrene equivalent weight average molecular weight of 500 to 100,000 as measured by gel permeation chromatography (GPC), preferably 1 to 100,000. More preferably, the molecular weight is from 000 to 50,000.

[Polyorganosiloxane]
The polyorganosiloxane in the present invention can be obtained, for example, by hydrolyzing or hydrolyzing / condensing a hydrolyzable silane compound, preferably in the presence of a suitable organic solvent, water and a catalyst.

  Examples of hydrolyzable silane compounds used for the synthesis of polyorganosiloxane include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and trimethoxysilylpropyl. Alkoxysilane compounds such as succinic anhydride, dimethyldimethoxysilane and dimethyldiethoxysilane; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3 Nitrogen-sulfur-containing compounds such as -aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (3-cyclohexylamino) propyltrimethoxysilane, etc. Xysilane compounds; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- Epoxy group-containing silane compounds such as (3,4-epoxycyclohexyl) ethyltriethoxysilane; 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryl Examples thereof include alkoxysilane compounds containing an unsaturated bond such as roxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and p-styryltrimethoxysilane. One of these hydrolyzable silane compounds can be used alone or in combination of two or more. In addition, "(meth) acryloxy" has a meaning including "acryloxy" and "methacryloxy".

  The above hydrolysis / condensation reaction can be carried out by reacting one or more of the above silane compounds with water, preferably in the presence of a suitable catalyst and an organic solvent. In the hydrolysis / condensation reaction, the use ratio of water is preferably 0.5 to 100 mol, more preferably 1 to 30 mol, per 1 mol of the silane compound (total amount).

Examples of the catalyst used in the hydrolysis / condensation reaction include an acid, an alkali metal compound, an organic base (such as triethylamine and tetramethylammonium hydroxide), a titanium compound, and a zirconium compound. The amount of the catalyst used depends on the type of the catalyst, reaction conditions such as temperature and the like, and should be appropriately set. For example, the amount is preferably 0.01 to 3 moles relative to the total amount of the silane compound. And more preferably 0.05 to 1 mole.
Examples of the organic solvent used in the above hydrolysis / condensation reaction include hydrocarbons, ketones, esters, ethers, alcohols and the like. 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 weight, more preferably 50 to 1,000 parts by weight, based on 100 parts by weight of the total amount of the silane compound used in the reaction.

  The above hydrolysis / condensation reaction is preferably carried out by heating, for example, in an oil bath or the like. During the hydrolysis / condensation reaction, the heating temperature is preferably 130 ° C. or lower, and the heating time is preferably 0.5 to 12 hours. After completion of the reaction, polysiloxane can be obtained by removing the solvent from the organic solvent layer separated from the reaction solution.

  When applied to a liquid crystal aligning agent for a TN type, STN type or vertical alignment type liquid crystal display device, or when imparting liquid crystal alignment ability to a coating film by a photo alignment method, a liquid crystal alignment property is added to a side chain of polyorganosiloxane. A specific group such as a group or a photo-alignment group may be introduced. The method for synthesizing the polyorganosiloxane having these specific groups in the side chain is not particularly limited.For example, an epoxy group is obtained by hydrolyzing and condensing an epoxy group-containing silane compound or a mixture of an epoxy group-containing silane compound and another silane compound. A method of synthesizing a polyorganosiloxane having a group, and then reacting the resulting epoxy group-containing polyorganosiloxane with the carboxylic acid having the specific group. The reaction between the epoxy group-containing polyorganosiloxane and the carboxylic acid can be performed according to a known method.

  The polyorganosiloxane has a weight average molecular weight (Mw) in terms of polystyrene measured by GPC of preferably from 500 to 100,000, more preferably from 1,000 to 30,000, More preferably, it is from 000 to 20,000. When the weight average molecular weight of the polyorganosiloxane is within the above range, it is easy to handle when producing a liquid crystal alignment film, and the obtained liquid crystal alignment film has sufficient material strength and properties.

As a preferred embodiment of the polymer component of the liquid crystal alignment agent,
[1] An embodiment in which the polymer component of the liquid crystal alignment agent is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide;
[2] Embodiments in which the polymer component of the liquid crystal aligning agent is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and polyorganosiloxane.
In the above embodiment [2], the content ratio of the polyorganosiloxane may be appropriately set, but is preferably 50% by weight or less, more preferably 30% by weight, based on the total amount of the polymer components in the liquid crystal aligning agent. It is more preferable to make the above.

  When a liquid crystal aligning ability is imparted to a coating film formed using a liquid crystal aligning agent by a photo alignment method, the ratio of the polymer having a photo aligning structure is determined by the ratio of the polymer (A) contained in the liquid crystal aligning agent. It is preferably at least 10% by weight, more preferably from 30 to 100% by weight, even more preferably from 50 to 100% by weight, based on the total amount. In addition, the polymer (A) can be used alone or in combination of two or more.

<Solvent>
The liquid crystal alignment agent of the present invention is a liquid composition in which a polymer component is dispersed or dissolved in a solvent. The liquid crystal alignment agent contains the following first solvent and second solvent as solvents.

[First solvent]
The first solvent comprises a compound represented by the above formula (1), a compound represented by the above formula (2), a compound represented by the above formula (3), and a compound represented by the above formula (4). At least one selected from the group consisting of: Preferably, R ¹ and R ^{2 in} the above formula (4) are methyl groups. Examples of the compound represented by the formula (4), N, N-dimethyl acetoacetamide, N, N-diethyl-acetoacetamide, and among them N, N-dimethyl acetoacetamide is preferred. The compound represented by the above formula (4) can be used alone or in combination of two or more. As the first solvent, a compound represented by the above formula (1) and a compound represented by the above formula (3) are particularly preferable, in that the effects of the present invention can be more suitably obtained. Incidentally, the first solvent may be used alone or in combination of two or more.

[Second solvent]
The second solvent is a solvent having a surface tension of less than 30 dyn / cm. In the present specification, the surface tension (dyn / cm) is a value at 25 ° C. As the second solvent, among others, a compound represented by the above formula (5), a compound represented by the above formula (6), a compound represented by the above formula (7), and a compound represented by the above formula (8) At least one selected from the group consisting of compounds is preferred.

(Compound represented by Formula (5))
Examples of the hydrocarbon group having 1 to 3 carbon atoms for R ⁵ and R ⁷ in the above formula (5) include an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group; And monovalent unsaturated chain hydrocarbon groups having 2 or 3 carbon atoms such as a group and an allyl group. Among these, R ⁵ and R ⁷ are preferably a methyl group or an ethyl group. Note that R ⁵ and R ⁷ may be the same or different from each other. Examples of the alkanediyl group having 2 to 5 carbon atoms for R ⁶ include an ethylene group, a propane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,3-diyl group, and a butane-1,4. -Diyl group, pentane-1,5-diyl group and the like.
Preferred specific examples of the compound represented by the above formula (5) include, for example, alkylene glycol diacetates such as ethylene glycol diacetate and propylene glycol diacetate. Among them, propylene glycol diacetate can be preferably used. As the compound represented by the formula (5), the above compounds can be used alone or in combination of two or more.

(Compound represented by Formula (6))
The compound represented by the above formula (6) has a structure in which two R ⁸ are each bonded to one oxygen atom. Specific examples of the compound in which R ⁸ is a monovalent group having one “—O—” between carbon-carbon bonds of an alkyl group having 3 to 5 carbon atoms, such as diethylene glycol dimethyl ether R ⁸ is a monovalent group in which a hydrogen atom of an alkyl group having 3 to 5 carbon atoms is substituted with a hydroxyl group, for example, dipropylene glycol; Specific examples of the compound in which ⁸ is a branched alkyl group include, for example, diisopropyl ether, diisopentyl ether, di-sec-butyl ether, di-sec-pentyl ether and the like. Among these, the compound represented by the formula (6) is preferably at least one of diethylene glycol diethyl ether and diisopentyl ether. In addition, as the compound represented by the above formula (6), the above compounds can be used alone or in combination of two or more.

(Compound represented by Formula (7))
X ¹ in the above formula (7) is preferably ^a group “—C (OH) R ^a —”, and more preferably a group “—C (OH) (CH ₃ ) —”. Further, the alkyl group having 1 to 4 carbon atoms of R ⁹ may be linear or branched, and is preferably a methyl group or an ethyl group.
Preferred specific examples of the compound represented by the above formula (7) include, for example, diacetone alcohol, acetylacetone, ethyl acetoacetate, and the like, and in particular, diacetone alcohol can be preferably used. In addition, as the compound represented by the above formula (7), the above compounds can be used alone or in combination of two or more.

(Compound represented by Formula (8))
In the above formula (8), the alkyl group having 1 to 6 carbon atoms of R ³ is preferably a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group or an i-butyl group, Butyl groups are particularly preferred. The alkanediyl group having 2 to ⁴ carbon atoms of R ⁴ is preferably an ethylene group, an n-propylene group or an i-propylene group, and particularly preferably an ethylene group.
Preferred specific examples of the compound represented by the formula (8) include, for example, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i. -Propyl ether and the like, and in particular, ethylene glycol-n-butyl ether can be preferably used. In addition, as the compound represented by the above formula (8), the above compounds can be used alone or in combination of two or more.

  As the second solvent, the compound represented by the above formula (5) and the compound represented by the above formula (7) are particularly preferred in that the combined use with the first solvent has a high effect of improving the printability and the swelling of the printing plate. It is more preferable that the compound is at least one selected from the group consisting of compounds represented by the following formula (7), and it is further preferable that the compound is a compound represented by the above formula (7).

The content ratio of the first solvent in the liquid crystal aligning agent is 5 to 95% by weight based on the total amount of the solvent contained in the liquid crystal aligning agent, from the viewpoint of achieving both suppression of polymer precipitation on a printing press and applicability. %, More preferably 10 to 90% by weight.
In addition, the content ratio of the second solvent is from 1 to 1 with respect to the total amount of the solvent contained in the liquid crystal alignment agent from the viewpoint of improving the applicability (printability) to the substrate while suppressing the precipitation of the polymer. Preferably it is 70% by weight, more preferably 3 to 60% by weight. As the second solvent, the above solvents can be used alone or in combination of two or more.

The particularly preferable use range of the first solvent and the second solvent differs depending on the solvent to be combined and the type of the solvent to be used. For example, a particularly preferable range of the usage ratio of the first solvent is that the second solvent is a compound represented by the above formula (5), a compound represented by the above formula (6) or a compound represented by the above formula (7) In this case, the content is particularly preferably 20 to 80% by weight based on the total amount of the solvent contained in the liquid crystal alignment agent. When the second solvent is a compound represented by the above formula (8), the first solvent is particularly preferably 40 to 90% by weight based on the total amount of the solvent contained in the liquid crystal aligning agent.
A particularly preferable range of the usage ratio of the second solvent is a compound represented by the above formula (5), a compound represented by the above formula (6) and a compound represented by the above formula (7). It is particularly preferable to set the content to 10 to 50% by weight based on the total amount of the solvent contained in the solvent. The content of the compound represented by the formula (8) is particularly preferably 5 to 30% by weight based on the total amount of the solvent contained in the liquid crystal aligning agent.

  The ratio of the first solvent to the second solvent may be 0.03 times or more by weight of the second solvent with respect to the first solvent from the viewpoint of improving the applicability to the substrate. More preferably, it is more preferably 0.05 times or more. Further, from the viewpoint of suppressing the precipitation of the polymer, it is preferably 2.5 times or less, more preferably 2.0 times or less.

[Third solvent]
As the solvent contained in the liquid crystal alignment agent of the present invention, other solvents (third solvent) other than the above-described first solvent and second solvent may be used. Examples of the third solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, ethylene glycol monomethyl ether Butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate , Dipropylene glycol monomethyl ether (DPM), diisobutyl ketone, isoamyl propionate, iso Amyl isobutyrate, ethylene carbonate, propylene carbonate and the like can be mentioned. The third solvent can be used alone or in combination of two or more.

The total content of the first solvent and the second solvent in the liquid crystal aligning agent of the present invention is preferably 10% by weight or more of the entire solvent contained in the liquid crystal aligning agent from the viewpoint of sufficiently obtaining the effects of the present invention. . It is more preferably at least 30% by weight, further preferably at least 50% by weight.
The content ratio of the third solvent is preferably less than 90% by weight, more preferably less than 70% by weight, and still more preferably less than 50% by weight, based on the total amount of the solvent contained in the liquid crystal aligning agent. .

<Other ingredients>
The liquid crystal aligning agent of the present invention contains the above-mentioned polymer component and solvent, but may contain other components as necessary. As such other components, for example, other polymers (for example, polyester, polyamide, polystyrene derivative, poly (meth) acrylate, etc.) other than the polymer (A), a compound having at least one epoxy group in a molecule, Examples include functional silane compounds, photopolymerizable compounds, surfactants, fillers, defoamers, sensitizers, dispersants, antioxidants, adhesion aids, antistatic agents, leveling agents, antibacterial agents, and the like. These blending ratios can be appropriately set according to the compound to be blended, as long as the effects of the present invention are not impaired.

  The solid content concentration (the ratio of the total weight of components other than the solvent of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) in the liquid crystal aligning agent of the present invention is appropriately selected in consideration of viscosity, volatility, and the like. , Preferably in the range of 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface as described later, and preferably heated to form a coating film serving as a liquid crystal alignment film or a coating film serving as a liquid crystal alignment film. At this time, when the solid content concentration is less than 1% by weight, the thickness of the coating film becomes too small, and it becomes difficult to obtain a good liquid crystal alignment film. On the other hand, when the solids concentration exceeds 10% by weight, the thickness of the coating film becomes excessively large, making it difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases to deteriorate the coating characteristics. There is a tendency.

  The particularly preferable range of the solid content concentration differs depending on the method used when applying the liquid crystal aligning agent to the substrate. For example, in the case of the spin coating method, the solid content concentration is particularly preferably in the range of 1.5 to 4.5% by weight. In the case of the offset printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of using the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s. The temperature at the time of preparing the liquid crystal alignment agent is preferably 10 to 50C, more preferably 20 to 30C.

<Liquid crystal alignment film and liquid crystal element>
The liquid crystal alignment film of the present invention is formed by the liquid crystal alignment agent prepared as described above. Further, a liquid crystal element of the present invention includes a liquid crystal alignment film formed using the above liquid crystal alignment agent. The driving mode to which the liquid crystal element is applied is not particularly limited, and can be applied to various driving modes such as a TN mode, an STN mode, an IPS mode, an FFS mode, a VA mode, an MVA mode, and a PSA mode. The liquid crystal element of the present invention can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, a substrate to be used is different depending on a desired driving mode. Steps 2 and 3 are common to each drive mode.

[Step 1: Formation of coating film]
First, the liquid crystal aligning agent of the present invention is applied on a substrate, and then the coated surface is heated to form a coating film on the substrate.
(1-1) When manufacturing a TN-type, STN-type, VA-type, MVA-type or PSA-type liquid crystal element, two substrates provided with a patterned transparent conductive film are paired, and a transparent substrate is used for each substrate. A liquid crystal aligning agent is preferably applied on the surface on which the conductive conductive film is formed, preferably by an offset printing method, a spin coating method, a roll coater method, or an inkjet printing method. Here, as the substrate, for example, a transparent substrate made of glass such as float glass or soda glass; or a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, or poly (alicyclic olefin) can be used. Examples of the transparent conductive film provided on one surface of the substrate include a NESA film made of tin oxide (SnO ₂ ) (registered trademark of PPG, USA) and an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ). Can be used.

  After the application of the liquid crystal alignment agent, preheating (prebake) is preferably performed for the purpose of preventing the applied alignment agent from dripping. The pre-bake temperature is preferably 30 to 200 ° C., and the pre-bake time is preferably 0.25 to 10 minutes. Thereafter, a baking (post-baking) step is performed for the purpose of completely removing the solvent and, if necessary, for thermally imidizing the amic acid structure present in the polymer. The firing temperature (post-bake temperature) at this time is preferably 80 to 300 ° C., and the post-bake time is preferably 5 to 200 minutes. The thickness of the film thus formed is preferably from 0.001 to 1 μm, more preferably from 0.005 to 0.5 μm.

(1-2) In the case of manufacturing an IPS type or FFS type liquid crystal display element, an electrode forming surface of a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb shape and an electrode are provided. A liquid crystal aligning agent is applied to one surface of the opposite substrate that has not been coated, and then each applied surface is heated to form a coating film. The materials used for the substrate and the transparent conductive film used at this time, the coating method, the heating conditions after the coating, the patterning method for the transparent conductive film or the metal film, the pretreatment of the substrate, and the preferable film thickness of the formed coating film are described above. This is the same as (1-1). As the metal film, for example, a film made of a metal such as chromium can be used.
In both cases (1-1) and (1-2), a liquid crystal alignment film is formed on the substrate by applying the liquid crystal alignment agent and then removing the organic solvent.

[Step 2: treatment for imparting alignment ability]
When manufacturing a TN-type, STN-type, IPS-type or FFS-type liquid crystal display device, a process of imparting liquid crystal alignment capability to the coating film formed in the above step 1 is performed. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. The orientation imparting treatment includes, for example, rubbing treatment in which the coating is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, cotton, and the like, and optical alignment in which the coating is irradiated with polarized or unpolarized radiation. Processing. On the other hand, in the case of manufacturing a VA liquid crystal display element, the coating film formed in the above step 1 can be used as it is as a liquid crystal alignment film, but the coating film may be subjected to an alignment ability imparting treatment.

  When imparting liquid crystal alignment capability to a coating film by photo-alignment treatment, the radiation applied to the coating film may be, for example, ultraviolet light or visible light including light having a wavelength of 150 to 800 nm. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized light or partially polarized light, the irradiation may be performed in a direction perpendicular to the substrate surface, may be performed in an oblique direction, or may be performed in combination. When irradiating unpolarized radiation, the irradiation direction is an oblique direction.

As a light source to be 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 and the like can be used. The ultraviolet light in a preferable wavelength range can be obtained by means using a light source in combination with, for example, a filter, a diffraction grating, or the like. The irradiation dose of radiation is preferably 100 to 50,000 J / m ² , and more preferably 300 to 20,000 J / m ² . Light irradiation on the coating film may be performed while heating the coating film in order to increase reactivity. The temperature at the time of heating is usually 30 to 250 ° C, preferably 40 to 200 ° C. A liquid crystal alignment film suitable for a VA liquid crystal display element can be suitably used for a PSA (Polymer sustained alignment) liquid crystal display element.

[Step 3: Construction of Liquid Crystal Cell]
A liquid crystal cell is manufactured by preparing two substrates on each of which a liquid crystal alignment film is formed as described above, and disposing a liquid crystal between the two substrates that are opposed to each other. In order to manufacture a liquid crystal cell, for example, (1) two substrates are opposed to each other with a gap therebetween so that a liquid crystal alignment film faces each other, and the peripheral portions of the two substrates are bonded to each other using a sealant; A method of injecting and filling liquid crystal into a cell gap defined by a substrate surface and a sealing agent, and then sealing the injection hole. (2) Applying a sealing agent to a predetermined location on one substrate on which a liquid crystal alignment film is formed Then, after dropping the liquid crystal at predetermined positions on the surface of the liquid crystal alignment film, the other substrate is attached to the liquid crystal alignment film so as to face the liquid crystal alignment film, and the liquid crystal is spread over the entire surface of the substrate (an ODF method). No. It is desirable that the manufactured liquid crystal cell is further heated to a temperature at which the used liquid crystal takes an isotropic phase, and then gradually cooled to room temperature to remove the flow alignment at the time of filling the liquid crystal.

  As the sealant, for example, an epoxy resin containing a hardening agent and aluminum oxide spheres as a spacer can be used. Examples of the liquid crystal include a nematic liquid crystal and a smectic liquid crystal, and among them, a nematic liquid crystal is preferable, for example, a Schiff base liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, and biphenyl. A cyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cubane liquid crystal, or the like can be used. Further, a cholesteric liquid crystal, a chiral agent, a ferroelectric liquid crystal, or the like may be added to these liquid crystals for use.

  When a PSA-type liquid crystal display element is manufactured, a liquid crystal cell is constructed in the same manner as described above except that a photopolymerizable compound is injected or dropped together with liquid crystal. After that, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. When a coating film is formed on a substrate using a liquid crystal aligning agent containing a photopolymerizable compound, a liquid crystal cell is constructed in the same manner as in the above (3-1), and then, a conductive film between a pair of substrates is formed. A liquid crystal element may be manufactured through a step of irradiating a liquid crystal cell with light while a voltage is applied to the liquid crystal cell.

  Then, by attaching a polarizing plate to the outer surface of the liquid crystal cell, the liquid crystal display device of the present invention can be obtained. As the polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film called "H film" in which polyvinyl alcohol is stretched and oriented while absorbing iodine is sandwiched by a cellulose acetate protective film or the H film itself. Can be mentioned.

  When the rubbing process is performed on the coating film, the two substrates are arranged to face each other so that the rubbing directions of the coating films are at a predetermined angle, for example, orthogonal or antiparallel. Further, when the coating film is irradiated with light, if the liquid crystal alignment film has horizontal alignment, the polarization direction of the irradiated linearly polarized radiation between the two substrates on which the liquid crystal alignment film is formed is formed. By adjusting the angle and the angle between each substrate and the polarizing plate, a liquid crystal element having a TN or STN liquid crystal cell can be obtained. On the other hand, when the liquid crystal alignment film has a vertical alignment property, the cells are configured such that the directions of the axes of easy alignment in the two substrates on which the liquid crystal alignment film is formed are parallel, and a polarizing plate is formed on the cell. A liquid crystal element having a vertical alignment type liquid crystal cell can be obtained by laminating such that the polarization direction forms an angle of 45 ° with the axis of easy alignment.

  The liquid crystal element of the present invention can be effectively applied to various devices, for example, a clock, a portable game, a word processor, a notebook computer, a car navigation system, a camcorder, a PDA, a digital camera, a mobile phone, a smartphone, various It can be used for a display device such as a monitor and a liquid crystal television, a light control film and the like. Further, a liquid crystal element formed using the liquid crystal alignment agent of the present invention can be applied to a retardation film.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.

The solution viscosity of each polymer solution, the imidation ratio of polyimide, the weight average molecular weight, and the epoxy equivalent in the synthesis examples were measured by the following methods.
[Solution viscosity of polymer solution]
The solution viscosity (mPa · s) of the polymer solution was measured at 25 ° C. using a predetermined solvent and adjusted to a polymer concentration of 10% by weight using an E-type rotational viscometer.
[Imidation rate of polyimide]
The solution of the polyimide was poured into pure water, and the obtained precipitate was sufficiently dried under reduced pressure at room temperature, then dissolved in deuterated dimethylsulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. From the obtained ¹ H-NMR spectrum, the imidation ratio [%] was determined by the following equation (1).
Imidation ratio [%] = (1−A ¹ / A ² × α) × 100 (1)
(In the formula (1), A ¹ is the peak area derived from the proton of the NH group, which appears near the chemical shift of 10 ppm, A ² is the peak area derived from the other protons, and α is the precursor of the polymer (polyamic acid ) Is the number ratio of other protons to one proton of the NH group.)
[Weight average molecular weight of polymer]
The weight average molecular weight Mw is a value in terms of polystyrene measured by gel permeation chromatography under the following conditions.
Column: TSKgelGRCXLII, manufactured by Tosoh Corporation
Solvent: tetrahydrofuran Temperature: 40 ° C
Pressure: 68 kgf / cm ²
[Epoxy equivalent]
The epoxy equivalent was measured by a hydrochloric acid-methyl ethyl ketone method described in JIS C 2105.

<Synthesis of polymer>
[Synthesis Example 1: Synthesis of polyimide (PI-1)]
22.4 g (0.1 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride (TCA) as tetracarboxylic dianhydride and 8.6 g (0.08 mol) of p-phenylenediamine (PDA) as diamine ) And 10.5 g (0.02 mol) of cholestanyl 3,5-diaminobenzoate (HCDA) were dissolved in 166 g of N-methyl-2-pyrrolidone (NMP) and reacted at 60 ° C. for 6 hours to obtain polyamic acid. Was obtained. A small amount of the obtained polyamic acid solution was fractionated, NMP was added thereto, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 90 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to make a solution having a polyamic acid concentration of 7% by weight, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration ring-closing reaction, the solvent in the system was solvent-replaced with fresh NMP (the pyridine and acetic anhydride used in the dehydration ring-closing reaction were removed from the system by this operation; the same applies hereinafter), resulting in an imidization ratio of about 68. % Polyimide (PI-1) was obtained. A small amount of the obtained polyimide solution was fractionated, NMP was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 45 mPa · s. Then, the reaction solution was poured into a large excess of methanol to precipitate a reaction product. The precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain a polyimide (PI-1).

[Synthesis Example 2: Synthesis of polyimide (PI-2)]
22.5 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 7.6 g (0.07 mol) of PDA as diamine, 5.2 g (0.01 mol) of HCDA and 4,4′-diaminodiphenylmethane (DDM) 4 0.0g (0.02 mol) was dissolved in 157g of NMP and reacted at 60 ° C for 6 hours to obtain a solution containing 20% by weight of polyamic acid. A small amount of the obtained polyamic acid solution was fractionated, NMP was added thereto, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 110 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to make a solution having a polyamic acid concentration of 7% by weight, 16.6 g of pyridine and 21.4 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 26% by weight of polyimide (PI-2) having an imidization ratio of about 82%. A small amount of the obtained polyimide solution was fractionated, NMP was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 62 mPa · s. Then, the reaction solution was poured into a large excess of methanol to precipitate a reaction product. The precipitate was washed with methanol and dried at 40 ° C. under reduced pressure for 15 hours to obtain polyimide (PI-2).

[Synthesis Example 3: Synthesis of polyimide (PI-3)]
As a tetracarboxylic dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride (BODA) 24.9 g (0.10 mol) Then, 8.6 g (0.08 mol) of PDA as a diamine and 10.4 g (0.02 mol) of HCDA were dissolved in 176 g of NMP and reacted at 60 ° C. for 6 hours to obtain a solution containing 20% by weight of polyamic acid. . A small amount of the obtained polyamic acid solution was taken out, NMP was added thereto, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 103 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to make a solution having a polyamic acid concentration of 7% by weight, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration ring closure reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 26% by weight of polyimide (PI-3) having an imidization ratio of about 71%. A small amount of the obtained polyimide solution was fractionated, NMP was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 57 mPa · s. Then, the reaction solution was poured into a large excess of methanol to precipitate a reaction product. This precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain polyimide (PI-3).

[Synthesis Example 4: Synthesis of polyimide (PI-4)]
As tetracarboxylic dianhydride, 110 g (0.50 mol) of TCA and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) naphtho 160 g (0.50 mol) of [1,2-c] furan-1,3-dione, 91 g (0.85 mol) of PDA as diamine, 25 g of 1,3-bis (3-aminopropyl) tetramethyldisiloxane ( 0.10 mol) and 25 g (0.040 mol) of 3,6-bis (4-aminobenzoyloxy) cholestane, and 1.4 g (0.015 mol) of aniline as a monoamine were dissolved in 960 g of NMP. By performing the reaction for 6 hours, a solution containing a polyamic acid was obtained. A small amount of the obtained polyamic acid solution was fractionated, NMP was added thereto, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 60 mPa · s.
Next, 2,700 g of NMP was added to the obtained polyamic acid solution, 390 g of pyridine and 410 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was solvent-replaced with fresh γ-butyrolactone to obtain about 2,500 g of a solution containing 15% by weight of a polyimide (PI-4) having an imidization ratio of about 95%. A small amount of this solution was fractionated, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 70 mPa · s. Then, the reaction solution was poured into a large excess of methanol to precipitate a reaction product. The precipitate was washed with methanol and dried at 40 ° C. under reduced pressure for 15 hours to obtain a polyimide (PI-4).

[Synthesis Example 5: Synthesis of polyimide (PI-5)]
22.4 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 8.6 g (0.08 mol) of PDA as diamine, 2.0 g (0.01 mol) of DDM, and 4,4′-diamino-2,2 ′ 3.2 g (0.01 mol) of -bis (trifluoromethyl) biphenyl was dissolved in 324 g of NMP and reacted at 60 ° C. for 4 hours to obtain a solution containing 10% by weight of polyamic acid.
Next, 360 g of NMP was added to the obtained polyamic acid solution, 39.5 g of pyridine and 30.6 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was solvent-substituted with fresh NMP to obtain a solution containing 10% by weight of polyimide (PI-5) having an imidization ratio of about 93%. The solution viscosity measured by dispensing a small amount of the obtained polyimide solution was 30 mPa · s. Then, the reaction solution was poured into a large excess of methanol to precipitate a reaction product. This precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain polyimide (PI-5).

[Synthesis Example 6: Synthesis of polyimide (PI-6)]
Synthesis Example 1 was repeated except that the diamine used was changed to 0.08 mol of 3,5-diaminobenzoic acid (3,5 DAB) and 0.02 mol of cholestanyloxy-2,4-diaminobenzene (HCODA). A polyamic acid solution was obtained in the same manner. A small amount of the obtained polyamic acid solution was taken out, NMP was added thereto, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 80 mPa · s.
Next, imidation was performed in the same manner as in Synthesis Example 1 above, to obtain a solution containing 26% by weight of polyimide (PI-6) having an imidization ratio of about 65%. A small amount of the obtained polyimide solution was fractionated, NMP was added thereto, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 40 mPa · s. Then, the reaction solution was poured into a large excess of methanol to precipitate a reaction product. This precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain polyimide (PI-6).

[Synthesis Example 7: Synthesis of polyamic acid (PA-1)]
200 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CB) as tetracarboxylic dianhydride and 210 g of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine (1.0 mol) was dissolved in a mixed solvent of 370 g of NMP and 3,300 g of γ-butyrolactone, and reacted at 40 ° C. for 3 hours to obtain a polyamic acid solution having a solid concentration of 10% by weight and a solution viscosity of 160 mPa · s. Was. Then, the polyamic acid solution was poured into a large excess of methanol to precipitate a reaction product. The precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain polyamic acid (PA-1).

[Synthesis Example 8: Synthesis of polyamic acid (PA-2)]
The tetracarboxylic dianhydride used is 0.9 mol of pyromellitic dianhydride (PMDA) and 0.1 mol of CB, and the diamine is 0.2 mol of PDA and 0.4 mol of 4,4′-diaminodiphenyl ether (DDE). A polyamic acid solution having a solid content of 10% by weight and a solution viscosity of 170 mPa · s was obtained in the same manner as in Synthesis Example 7 except that the amount was changed to 8 mol. Then, the polyamic acid solution was poured into a large excess of methanol to precipitate a reaction product. The precipitate was washed with methanol and dried at 40 ° C. under reduced pressure for 15 hours to obtain a polyamic acid (PA-2).

[Synthesis Example 9: Synthesis of polyamic acid (PA-3)]
7.0 g (0.031 mol) of TCA as a tetracarboxylic dianhydride and 13 g (corresponding to 1 mol per 1 mol of TCA) of a compound represented by the following formula (R-1) as a diamine are dissolved in 80 g of NMP. Then, the solution was reacted at 60 ° C. for 4 hours to obtain a solution containing 20% by weight of polyamic acid (PA-3). The solution viscosity of this polyamic acid solution was 2,000 mPa · s. In addition, the compound represented by the following formula (R-1) was synthesized according to the description in JP-A-2011-100099. Then, the polyamic acid solution was poured into a large excess of methanol to precipitate a reaction product. The precipitate was washed with methanol and dried under reduced pressure at 40 ° C. for 15 hours to obtain polyamic acid (PA-3).

[Synthesis Example 10: Synthesis of polyorganosiloxane (APS-1)]
In a reaction vessel equipped with a stirrer, thermometer, dropping funnel and reflux condenser, 100.0 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (ECETS), 500 g of methyl isobutyl ketone and 10.0 g of triethylamine were added. Charged and mixed at room temperature. Next, 100 g of deionized water was dropped from the dropping funnel over 30 minutes, and the mixture was reacted at 80 ° C. for 6 hours while stirring under reflux. After completion of the reaction, the organic layer is taken out, washed with a 0.2% by weight aqueous solution of ammonium nitrate until the washed water becomes neutral, and then the solvent and water are distilled off under reduced pressure to obtain a reactive polyorganosiloxane. (EPS-1) was obtained as a viscous transparent liquid. When ¹ H-NMR analysis was performed on this reactive polyorganosiloxane (EPS-1), a peak based on an epoxy group was obtained at a chemical shift (δ) of around 3.2 ppm in accordance with the theoretical intensity. It was confirmed that no side reaction of the epoxy group occurred. The obtained reactive polyorganosiloxane had a weight average molecular weight Mw of 3,500 and an epoxy equivalent of 180 g / mol.
Next, in a 200 mL three-necked flask, 10.0 g of the reactive polyorganosiloxane (EPS-1), 30.28 g of methyl isobutyl ketone as the solvent, 3.98 g of 4-dodecyloxybenzoic acid as the reactive compound, and UCAT as the catalyst 0.10 g of 18X (trade name, manufactured by San Apro Co., Ltd.) was charged, and the reaction was carried out at 100 ° C. with stirring for 48 hours. After completion of the reaction, a solution obtained by adding ethyl acetate to the reaction mixture was washed three times with water, the organic layer was dried using magnesium sulfate, and then the solvent was distilled off to obtain a liquid crystal aligning polyorganosiloxane (APS- 9.0 g of 1) was obtained. The weight average molecular weight Mw of the obtained polymer was 9,900.

[Synthesis Example 11: Synthesis of polyimide (PI-7)]
220 g (1.0 mol) of TCA as tetracarboxylic dianhydride, 49 g (0.1 mol) of 3- (2,4-diaminophenoxy) cholestane as diamine, 1- (4-aminophenyl) -2,3- 53 g (0.2 mol) of dihydro-1,3,3-trimethyl-1H-indene-5-amine, 54 g (0.2 mol) of a compound represented by the following formula (d-2), and 99 g of DDM (0.2 mol). (5 mol) was dissolved in 1,900 g of NMP and reacted at 60 ° C. for 6 hours to obtain a solution containing polyamic acid. The solution viscosity measured by dispensing a small amount of the obtained polyamic acid solution was about 1,400 mPa · s.
Then, 2,400 g of NMP was added to the obtained polyamic acid solution, and 120 g of pyridine (corresponding to 1.5 mol per 1 mol of the amic acid unit of the above polyamic acid) and 153 g of acetic anhydride (of the above polyamic acid). (Equivalent to 1.5 times the mole number of the amic acid unit contained).) And a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration and ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing about 15% by weight of polyimide (PI-7) having an imidization ratio of about 61%.

[Example 1]
<Preparation of liquid crystal alignment agent>
Polyimide (PI-1) was used as the polymer (A), and N, N-dimethylpropionamide (DMP) and diacetone alcohol (DAA) were added as solvents to the polymer (A). The solvent composition was DMP: DAA = 60: 40 ( Weight ratio) and a solution having a solid content of 6.5% by weight. This solution was filtered using a filter having a pore size of 1 μm to prepare a liquid crystal aligning agent (S-1). The liquid crystal aligning agent (S-1) is mainly used for manufacturing a vertical alignment type liquid crystal display device.

<Evaluation of swelling characteristics of printing plate>
Using the liquid crystal aligning agent (S-1), the swellability (swelling characteristics) of the APR plate was evaluated. The APR plate is a resin plate formed of a liquid photosensitive resin in which an ultraviolet irradiation part is cured, and is generally used for a printing plate of a liquid crystal alignment film printing machine. The fact that the APR plate is less likely to swell when the liquid crystal aligning agent is brought into contact with the APR plate means that the liquid crystal aligning agent is less likely to penetrate into the APR plate during printing and has good printability. The swelling property was evaluated by immersing the APR plate in a liquid crystal aligning agent for one day and measuring the change in weight of the APR plate before and after immersion. At this time, when the increase rate (swelling rate) of the weight of the APR plate is less than 4.0%, the APR plate hardly swells (good), and when the increase rate is 4.0% or more, the APR plate becomes It was easily swollen and evaluated as poor (x). As a result, in this example, the swelling ratio was 3.5%, and the swelling characteristics were “good (○)”. The swelling ratio was calculated using the following equation (2).
Swelling ratio [%] = (W ² −W ¹ / W ¹ ) × 100 (2)
(In Equation (2), ^{W 1} is the weight of the APR plate before immersion, ^{W 2} is the weight of APR plate after immersion.)

<Evaluation of printability>
With respect to the liquid crystal aligning agent (S-1) prepared above, printability (continuous printability) when printing on a substrate was continuously performed was evaluated. The evaluation was performed as follows. First, using a liquid crystal alignment film printing machine (manufactured by Nissha Printing Co., Ltd., Angstromer type “S40L-532”), the amount of the liquid crystal alignment agent (S-1) dropped on the anilox roll was reciprocated by 20 drops. (About 0.2 g), printing was performed on the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film. Printing on the substrate was performed 20 times at 1 minute intervals using a new substrate.
Subsequently, the liquid crystal aligning agent (S-1) is dispensed (one way) on the anilox roll at one-minute intervals, and each time the work of bringing the anilox roll into contact with the printing plate (hereinafter, referred to as idle operation) is performed 10 times in total. (Printing on the glass substrate was not performed during this time). The idle operation is an operation performed for intentionally performing printing of the liquid crystal alignment agent under severe conditions.
After ten idle operations, main printing was subsequently performed using a glass substrate. In this printing, after idling, five substrates are inserted at intervals of 30 seconds, each substrate after printing is heated (prebaked) at 80 ° C. for 1 minute to remove the solvent, and then heated at 200 ° C. for 10 minutes ( Post baking) to form a coating film having a thickness of about 80 nm. The printability (continuous printability) was evaluated by observing the coating film with a microscope having a magnification of 20 times. In the evaluation, continuous printability was “good (（)” when no polymer precipitation was observed from the first printing after the idling, and polymer deposition was observed at the first printing after the idling. Continuous printability "Possible (△)" when no polymer precipitation is observed during the fifth printing, and continuous polymer printing even after 5 times of the final printing. The printability was evaluated as "poor (x)". As a result, in this example, the continuous printability was “good (○)”. Experiments have shown that a liquid crystal aligning agent having good printability improves (disappears) the precipitation of the polymer while the substrate is continuously charged. Further, the number of idle operations was changed to 15, 20, and 25 times, and the printability of the liquid crystal alignment agent was evaluated in the same manner as described above. In this example, the idle operation was performed 15 times and 20 times. When the number of times was 25, it was "good (O)", and when it was 25 times, it was "OK (△)".

[Examples 2 to 32 and Comparative Examples 1 and 2]
The liquid crystal aligning agents (S-2) to (S-32) were prepared in the same manner as in Example 1 except that the type and composition of the polymer to be used and the solvent were changed as described in Table 1 below. (SR-1) and (SR-2) were prepared respectively. The swelling characteristics and printability of the printing plate were evaluated for each liquid crystal alignment agent in the same manner as in Example 1 above. The results are shown in Table 1 below.

In Table 1, with respect to those using two kinds of polymers as the polymer components (Examples 21 to 32), the use ratio (weight ratio) of each polymer to 100 parts by weight of the total amount of the used polymers was also added. Shown. Among the liquid crystal alignment agents, (S-2) to (S-20), (SR-1) and (SR-2) are mainly vertical alignment type, and (S-21) to (S-24) are mainly TN type, (S-25) to (S-28) and (S-30) to (S-32) are mainly for manufacturing an IPS type liquid crystal display element, and (S-29) is mainly for This is for manufacturing an optical FFS type liquid crystal display element.
In Table 1, the numerical value of the solvent composition indicates the compounding ratio (weight ratio) of each compound to the total amount of the solvent used for preparing the liquid crystal aligning agent. The symbols of the solvent compositions have the following meanings.
a: N, N-dimethylpropionamide (compound represented by the above formula (1))
b: N, N-diethylformamide (compound represented by the above formula (2))
c: Tetramethylurea (compound represented by the above formula (3))
d: N, N-dimethyl acetoacetamide e: N-methyl-2-pyrrolidone f: N-ethyl-2-pyrrolidone g: .gamma.-butyrolactone h: butyl cellosolve j: Propylene glycol diacetate k: diacetone alcohol l: Diethylene glycol Diethyl ether m: diisopentyl ether

  From the above results, it was found that all of the liquid crystal aligning agents of the examples hardly swell the printing plate and have good continuous printability. On the other hand, the result of the comparative example was inferior to the example in the swelling characteristics.

[Example 29A]
<Production of liquid crystal display element and evaluation of liquid crystal orientation>
A glass substrate having a metal electrode made of chrome patterned in a comb-like shape on one side, and a pair of a counter glass substrate on which no electrode is provided, and a surface having electrodes of the glass substrate and a surface of the counter glass substrate, Each of the liquid crystal alignment agents (S-29) prepared above was applied using a spinner. Next, pre-baking was performed for 1 minute on a hot plate at 80 ° C., and then heating (post-baking) was performed at 200 ° C. for 1 hour in an oven in which the inside of the refrigerator was purged with nitrogen to form a coating film having a thickness of 0.1 μm. Next, the surfaces of these coating films were irradiated with polarized ultraviolet rays of 10,000 J / m ² from the direction perpendicular to the substrate surface using an Hg-Xe lamp and a Glan-Taylor prism, respectively, to obtain a pair of substrates having a liquid crystal alignment film. Was.

  Next, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 μm is applied to the outer periphery of the surface of one of the pair of substrates having the liquid crystal alignment film by screen printing. The substrates were overlapped and pressed together so that the directions of the substrates when the polarized ultraviolet rays were irradiated were reversed, and the adhesive was thermally cured at 150 ° C. for 1 hour. Next, after filling the gap between the substrates with the liquid crystal “MLC-7028” manufactured by Merck from the liquid crystal injection port, the liquid crystal injection port was sealed with an epoxy-based adhesive. Further, in order to remove the flow alignment at the time of injecting the liquid crystal, it was heated at 150 ° C. and then gradually cooled to room temperature. Next, a polarizing plate is attached to both outer surfaces of the substrate such that the polarization directions thereof are orthogonal to each other and the direction of projection of the optical axis of the polarized ultraviolet light of the liquid crystal alignment film onto the substrate surface is orthogonal to the liquid crystal display. The device was manufactured.

<Evaluation of liquid crystal orientation>
With respect to the liquid crystal display device manufactured as described above, the presence or absence of an abnormal domain in the change in brightness when a voltage of 5 V was applied / released was observed with an optical microscope. In the evaluation, the case where no abnormal domain was observed was evaluated as “good” for liquid crystal alignment, and the case where abnormal domains were observed was evaluated as “bad” for liquid crystal alignment. As a result, no abnormal domains were observed in this liquid crystal display element, and the liquid crystal alignment was “good”.

Claims (8)

At least one polymer (A) selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane;
A first solvent is at least one selected from the group consisting of compounds represented by compound Mono及 beauty formula (4) represented by the following formula (1), the second solution has a surface tension of less than 30 dyn / cm And a liquid crystal aligning agent containing:

(In the formula (4), R ¹ and R ² are each independently a methyl group or an ethyl group.) The second solvent is a compound represented by the following formula (5), a compound represented by the following formula (6), a compound represented by the following formula (7), and a compound represented by the following formula (8) The liquid crystal aligning agent according to claim 1, which is at least one selected from the group consisting of:

(In the formula (5), R ⁵ and R ⁷ are each independently a monovalent hydrocarbon group having 1 to 3 carbon atoms, and R ⁶ is an alkanediyl group having 2 to 5 carbon atoms.)

(In the formula (6), R ⁸ is a monovalent group having one “—O—” between carbon-carbon bonds of a linear or branched alkyl group having 3 to 5 carbon atoms; A monovalent group in which at least one hydrogen atom of a linear or branched alkyl group having 5 to 5 carbon atoms is substituted with a hydroxyl group, or a branched alkyl group having 3 to 5 carbon atoms.)

(In the formula (7), X ¹ represents —C (OH) R ^a — (where ^Ra is a methyl group or an ethyl group), —CO— or —COO- * (where * represents R ⁹ And R ⁹ is an alkyl group having 1 to 4 carbon atoms.)

(In the formula (8), R ³ is an alkyl group having 1 to 6 carbon atoms, and R ⁴ is an alkanediyl group having 2 to ⁴ carbon atoms.)   The liquid crystal aligning agent according to claim 1 or 2, wherein the total content of the first solvent and the second solvent is 10% by weight or more of the entire solvent contained in the liquid crystal aligning agent.   The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the content of the second solvent is 1 to 70% by weight of the entire solvent contained in the liquid crystal aligning agent.   The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the content of the first solvent is 5 to 95% by weight of the entire solvent contained in the liquid crystal aligning agent.   As the polymer (A), 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8- At least one member selected from the group consisting of dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride And at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide obtained by reacting a dicarboxylic acid with a tetracarboxylic acid dianhydride, wherein the compound according to any one of claims 1 to 5. Liquid crystal alignment agent.   The liquid crystal aligning agent according to any one of claims 1 to 6, wherein the polymer (A) includes a polymer having a photoalignable structure. Applying a liquid crystal aligning agent according to claim 7 onto a substrate to form a coating film;
Irradiating the coating film with light to form a liquid crystal alignment film.