JPWO2016129506A1 - Liquid crystal alignment agent - Google Patents

Abstract

Provided is a liquid crystal aligning agent suitable for an ink jet method, from which a liquid crystal alignment film excellent in film thickness uniformity, film edge linearity and dimensional stability is obtained. Containing at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and a solvent, wherein the solvent comprises (A) γ-valerolactone, (B) γ-butyrolactone, and (C And a compound represented by the following formula (c). R1 and R3 are hydrogen atoms, R2 is an alkanediyl group having 2 or 3 carbon atoms, n is 1 or 2, and R4 is an alkyl group having 1 to 5 carbon atoms. [Chemical 1]

Description

  The present invention relates to a liquid crystal aligning agent for obtaining a liquid crystal aligning film, and more particularly to a liquid crystal aligning agent, a liquid crystal aligning film and a liquid crystal display element suitable for application by an ink jet method.

As a liquid crystal alignment film used for a liquid crystal display element or the like, a polyimide resin film is widely used. This polyimide-based liquid crystal alignment film is produced by applying a liquid crystal alignment agent mainly composed of a polymer such as polyamic acid, polyamic acid ester, and polyimide and a solvent to a substrate.
Conventionally, a flexographic printing method has been the mainstream as a method for applying a liquid crystal aligning agent, but in recent years, the use of an ink jet method has gradually increased from the viewpoint of cost merit. However, the liquid crystal alignment film obtained by coating by the ink jet method has a trade-off relationship between the film thickness uniformity within the coating surface and the shape control of the coating edge.

  For example, if a liquid crystal aligning agent with high uniformity in the paint film surface is applied by the ink jet method, the shape of the paint film edge is disturbed and does not become a straight line, or wets and spreads beyond the set dimensions, and the liquid crystal aligns even to unnecessary parts. The film may be covered. On the contrary, when a liquid crystal aligning agent in which the coating film ends are straight or a liquid crystal aligning agent with little wetting spread, there are problems such as insufficient in-plane uniformity.

  In order to solve such a problem, a method of confining a liquid crystal aligning agent within a predetermined range by a structure has been proposed (see Patent Document 1, Patent Document 2, and Patent Document 3). Moreover, as a means to solve by the composition of the liquid crystal aligning agent, a method of using an alkyl cellosolve acetate as a solvent for simultaneously improving the uniformity in the coating film surface and the linearity of the coating film edge (see Patent Document 4) In addition, as a method for simultaneously improving the uniformity in the surface of the coating film and the dimensional stability of the coating film, a method of using an alkyl cellosolve acetate and dipropylene glycol monomethyl ether in a solvent has been proposed (see Patent Document 5). .

Japanese Unexamined Patent Publication No. 2004-361623 Japanese Unexamined Patent Publication No. 2008-145461 Japanese Unexamined Patent Publication No. 2010-281925 International Publication WO2012 / 133826 Pamphlet International Publication No. WO2014 / 024885 Pamphlet

  Among the conventional methods described above, the method using the structure has a drawback that the manufacturing process of the liquid crystal panel increases. Moreover, although the method which uses alkyl cellosolve acetate for a solvent and the method which uses alkyl cellosolve acetate and dipropylene glycol monomethyl ether each have the outstanding effect, sufficient characteristic is not achieved in order to achieve a subject.

  An object of the present invention is to provide a new liquid crystal aligning agent suitable for an ink jet method, which is excellent in film thickness uniformity in a coating film surface, linearity of a coating film end, and dimensional stability of a coating film. It is in.

（式中、Ｒ^１、Ｒ^３はそれぞれ独立して水素原子、炭素数１〜４のアルキル基、又はアセチル基であり、Ｒ^２は、炭素数２又は３のアルカンジイル基であり、ｎは１又は２である。）As a result of intensive studies, the present inventors have completed the present invention capable of achieving the above-described problems. That is, the present invention has the following gist.
1. A liquid crystal aligning agent comprising at least one polymer selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide, and a solvent, wherein the solvent comprises (A) γ-valerolactone, (B) A liquid crystal aligning agent comprising γ-butyrolactone and (C) a compound represented by the following formula (c).

(Wherein R ¹ and R ³ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an acetyl group, R ² is an alkanediyl group having 2 or 3 carbon atoms, and n is 1 or 2)

2. The liquid crystal aligning agent of said 1 whose content of (A) is 20-75 mass% of the whole solvent.
3. In the above 1, the content of (A) is 20 to 75% by mass, the content of (B) is 20 to 75% by mass, and the content of (C) is 5 to 60% by mass with respect to the entire solvent. The liquid crystal aligning agent of description.
4). 2. The liquid crystal aligning agent according to 1 above, wherein the solvent further contains N-methyl-2-pyrrolidone.

5. The content of (A) is 20 to 70% by mass, the content of (B) is 20 to 70% by mass, the content of (C) is 5 to 55% by mass, and N-methyl-2, based on the whole solvent. -Liquid crystal aligning agent of said 4 whose content of pyrrolidone is 3-55 mass%.
6). 6. Liquid crystal aligning agent of any one of said 1-5 whose content of a polymer is 1-5 mass%.
7). The liquid crystal aligning agent of any one of said 1-6 for apply | coating to a board | substrate by the inkjet method.
8). The liquid crystal aligning film obtained from the liquid crystal aligning agent of any one of said 1-7.
9. The manufacturing method of the liquid crystal aligning film which apply | coats the liquid crystal aligning agent of any one of said 1-6 by the inkjet method.
10. 9. A liquid crystal display device comprising the liquid crystal alignment film as described in 8 above.

  According to the liquid crystal aligning agent of the present invention, a liquid crystal aligning film excellent in film thickness uniformity, linearity and dimensional stability in the periphery of the film can be obtained on the substrate, particularly also by the ink jet method. . Thereby, a highly reliable liquid crystal display element in which problems such as display unevenness are suppressed can be obtained.

<Polymer>
The liquid crystal aligning agent of the present invention contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. The structure of these polymers is not particularly limited as long as it can be used as a liquid crystal alignment film. Moreover, these polymers may be one kind in the liquid crystal aligning agent of this invention, and multiple types may be mixed.

Examples of preferable polyamic acid, polyamic acid ester, and polyimide in the present invention include a polymer having a repeating unit represented by the following formula (1). Moreover, as a preferable polyimide, in the polymer having a repeating unit represented by the formula (1), a polymer having an imide ring formed by intramolecular condensation accompanied by elimination of OR and A can be exemplified.

In the above formula (1), X represents a tetravalent organic group, two Rs each represent a hydrogen atom or a monovalent organic group, Y represents a divalent organic group, and two As each represent Represents a hydrogen atom or a monovalent organic group. In addition, X, Y, R, and A may each have a plurality of structures mixed in the polymer.
In addition, the polymer which consists of the repeating unit whose two R of said Formula (1) is a hydrogen atom is a polyamic acid, The polymer whose at least one part of R in this polyamic acid is a monovalent organic group Is a polyamic acid ester. A polymer in which at least a part of OR and A corresponding to this OR are eliminated and condensed in the molecule to form an imide ring is polyimide.

Although the structure of X in the formula (1) is not particularly limited, the following X-1 to X-46 can be mentioned as specific examples.

  Among these, X-1, X-2, X-3, X-4, X-5, X-6, X-8, X-16, X-19, X-21, X-25, X-26 X-27, X-28 or X-32 is preferred. These preferable Xs are preferably 2 to 100 mol%, more preferably 40 to 100 mol% of the total X in the polymer.

  The structure of Y in the formula (1) is not particularly limited, but the following Y-1 to Y-103 can be mentioned as specific examples.

  Among these, Y-7, Y-8, Y-10, Y-11, Y-12, Y-13, Y-20, Y-21, Y-22 are obtained because good liquid crystal orientation is obtained. Y-23, Y-25, Y-26, Y-27, Y-28, Y-29, Y-30, Y-41, Y-42, Y-43, Y-44, Y-45, Y -46, Y-48, Y-61, Y-63, Y-64, Y-71, Y-72, Y-73, Y-74, Y-75, or Y-98 are preferred. The preferable Y content is preferably 1 to 100 mol%, more preferably 50 to 100 mol% of the total Y in the polymer.

  Further, since the afterimage due to the accumulation of DC voltage can be reduced by lowering the volume resistivity of the liquid crystal alignment film, it is preferable to use a structure having a hetero atom, a polycyclic aromatic structure, or a biphenyl structure in the polymer. As such Y, Y-19, Y-23, Y-25, Y-26, Y-27, Y-30, Y-31, Y-32, Y-33, Y-34, Y-35, Y -36, Y-40, Y-41, Y-42, Y-44, Y-45, Y-49, Y-50, Y-51, or Y-61 are more preferable, Y-31, or Y- 40 is particularly preferred. The Y content is preferably 1 to 100 mol%, more preferably 50 to 100 mol% of the total Y contained in the polymer.

  In addition, since the pretilt angle of the liquid crystal can be increased, the side chain of the polymer preferably has a long-chain alkyl group, an aromatic ring, an aliphatic ring, a steroid skeleton, or a combination of these. As such Y, Y-76, Y-77, Y-78, Y-79, Y-80, Y-81, Y-82, Y-83, Y-84, Y-85, Y-86, Y -87, Y-88, Y-89, Y-90, Y-91, Y-92, Y-93, Y-94, Y-95, Y-96, or Y-97 are more preferred. The content of Y is preferably 10 to 90 mol%, more preferably 10 to 40 mol% of the total Y contained in the polymer.

  Two R in the formula (1) each independently represents a hydrogen atom or a monovalent organic group. In the case of a monovalent organic group, an aryl group or an alkyl group having 1 to 4 carbon atoms is preferable. Specific examples include a hydrogen atom, a methyl group, and an ethyl group. In the case where the polymer having the repeating unit represented by the formula (1) is used as a polyimide precursor, R is preferably a hydrogen atom or a methyl group from the viewpoint of ease of intramolecular condensation.

Two A's in the formula (1) each independently represent a hydrogen atom or a monovalent organic group. In the case of a monovalent organic group, an alkyl group, alkenyl group or alkynyl group having 1 to 10 carbon atoms is preferable. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, a hexyl group, an octyl group, a decyl group, a cyclopentyl group, a cyclohexyl group, and a bicyclohexyl group. Examples of the alkenyl group include those obtained by replacing one or more CH ₂ —CH ₂ structures present in the above alkyl group with a CH═CH structure, and more specifically, vinyl groups, allyl groups, 1- Examples include propenyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, 2-hexenyl group, cyclopropenyl group, cyclopentenyl group, and cyclohexenyl group. Alkynyl groups include those in which one or more CH ₂ —CH ₂ structures present in the alkyl group are replaced with C≡C structures, and more specifically, ethynyl groups, 1-propynyl groups, 2 -A propynyl group etc. are mentioned.

<Method for producing polyamic acid>
A polyamic acid can be obtained by reaction of tetracarboxylic dianhydride and diamine. For example, a polyamic acid composed of a repeating unit in which two Rs in the formula (1) are both hydrogen atoms is represented by a tetracarboxylic dianhydride represented by the following formula (2) and a formula (3). It can be obtained by reaction with diamine. X in formula (2) and Y and A in formula (3) are the same as defined in formula (1), respectively.

Specifically, tetracarboxylic dianhydride and diamine are reacted in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C. for 30 minutes to 24 hours, preferably 1 to 12 hours. Can be synthesized.
The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the monomer and the polymer, and these may be used alone or in combination of two or more. It may be used. The concentration of the polymer in the reaction system is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight body is easily obtained.

  The obtained polyamic acid can be recovered by precipitating the polymer by pouring it into a poorly polymer-soluble solvent (hereinafter also referred to as a poor solvent) while thoroughly stirring the reaction solution. Moreover, the powder of polyamic acid refine | purified by performing precipitation several times, washing | cleaning with a poor solvent, and normal temperature or heat-drying can be obtained. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned. The weight average molecular weight of the polyamic acid is preferably 10,000 to 305,000, and more preferably 20,000 to 210,000. Further, the number average molecular weight is preferably 5,000 to 152,500, more preferably 10,000 to 105,000.

<Method for producing polyamic acid ester>
(1) When synthesizing from polyamic acid The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic dianhydride and diamine.
Specifically, the polyamic acid and the esterifying agent are reacted in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C. for 30 minutes to 24 hours, preferably 1 to 4 hours. Can be synthesized.
As the esterifying agent, those that can be easily removed by purification are preferred, and N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide Dineopentyl butyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p -Tolyltriazene, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The addition amount of the esterifying agent is preferably 2 to 6 molar equivalents per 1 mol of the polyamic acid repeating unit.

  The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the polymer, and these may be used alone or in combination of two or more. Good. The concentration of the polymer in the reaction system is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight body is easily obtained.

(2) When synthesized by reaction of tetracarboxylic acid diester dichloride and diamine The polyamic acid ester can also be synthesized from tetracarboxylic acid diester dichloride and diamine. For example, the polyamic acid ester in which two Rs in the formula (1) are both monovalent organic groups is represented by the tetracarboxylic acid diester dichloride represented by the following formula (4) and the formula (3). It can be obtained by reaction with diamine. R in the formula (4) is the same as the definition in the formula (1).

Specifically, tetracarboxylic acid diester dichloride and diamine are -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C in the presence of a base and an organic solvent, for 30 minutes to 24 hours, preferably 1 to 4 hours. It can be synthesized by reacting.
As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 times the molar amount of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.

  The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of the solubility of the monomer and polymer, and these may be used alone or in combination. The polymer concentration in the reaction system is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight body is easily obtained. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent mixing of outside air in a nitrogen atmosphere.

(3) When synthesizing polyamic acid from tetracarboxylic acid diester and diamine Polyamic acid ester can also be synthesized by polycondensation of tetracarboxylic acid diester and diamine. For example, a polyamic acid ester in which two Rs in the formula (1) are both monovalent organic groups includes a tetracarboxylic acid diester represented by the following formula (5) and a diamine represented by the above formula (3). Can be obtained by reaction with. In addition, R of Formula (5) is the same as the definition in said Formula (1).

Specifically, tetracarboxylic acid diester and diamine in the presence of a condensing agent, a base, and an organic solvent are 0 ° C to 150 ° C, preferably 0 ° C to 100 ° C, 30 minutes to 24 hours, preferably 3 to 15 hours. It can synthesize | combine by making it react for time.
Examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazi Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N , N ′, N′-tetramethyluronium hexafluorophosphate, diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate, and the like. It is preferable that the addition amount of a condensing agent is 2-3 times mole with respect to tetracarboxylic-acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 to 4 moles relative to the diamine component from the viewpoint that it can be easily removed and a high molecular weight product can be easily obtained.
In the above reaction, the reaction proceeds efficiently by adding Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0 to 1.0 times the mole of the diamine component.

Among the methods for synthesizing the three polyamic acid esters, since a high molecular weight polyamic acid ester is obtained, the synthesis method (1) or (2) is particularly preferable.
The resulting polyamic acid ester solution can be precipitated into a polymer poorly soluble solvent (poor solvent) while stirring well to precipitate the polymer. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.
The weight average molecular weight of the polyamic acid ester is preferably 5,000 to 300,000, and more preferably 10,000 to 200,000. The number average molecular weight is preferably 2,500 to 150,000, more preferably 5,000 to 100,000.

<Production method of polyimide>
A polyimide is obtained by imidating said polyamic acid or polyamic acid ester. As such an imidization method, thermal imidization by heating or catalytic imidization using a catalyst is generally used. The catalytic imidation in which the imidization reaction proceeds at a relatively low temperature is preferable because the molecular weight of the resulting polyimide is less likely to decrease.
Catalytic imidation can be carried out in an organic solvent by stirring the polyamic acid in the presence of a basic catalyst and an acid anhydride, or stirring the polyamic acid ester in the presence of a basic catalyst. The reaction temperature at this time is -20 to 250 ° C, preferably 0 to 180 ° C. In the catalytic imidation of polyamic acid, the higher the reaction temperature, the faster the imidization proceeds. However, when the reaction temperature is too high, the molecular weight of the polyimide may decrease. The amount of the basic catalyst is 1 to 60 moles, preferably 2 to 40 moles per mole of the repeating unit of the polyamic acid or polyamic acid ester. The amount of the acid anhydride for catalytic imidation of the polyamic acid is 2 to 100 times, preferably 6 to 60 times the mole of the repeating unit of the polyamic acid. If the amount of the basic catalyst or acid anhydride is small, the reaction does not proceed sufficiently. If the amount is too large, it becomes difficult to completely remove the reaction after completion of the reaction.

  Examples of the basic catalyst used for the catalytic imidation of polyamic acid include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, etc. Among them, pyridine is preferable because it has an appropriate basicity to proceed the reaction. . Examples of the basic catalyst used for the catalytic imidation of the polyamic acid ester include triethylamine, trimethylamine, tributylamine, trioctylamine and the like, and triethylamine is particularly preferable because of its fast reaction.

  Examples of the acid anhydride used for the catalytic imidation of polyamic acid include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Of these, use of acetic anhydride is preferred because purification after completion of the reaction is facilitated. As an organic solvent, if a polyamic acid or polyamic acid ester melt | dissolves, it will not be limited. Specific examples thereof include N, N′-dimethylformamide, N, N′-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethyl urea, dimethyl sulfone, hexamethyl sulfoxide. , Γ-butyrolactone, γ-valerolactone, and the like. The imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

  The generated polyimide is obtained by collecting the reaction solution into a polymer poorly soluble solvent (also referred to as a poor solvent) and collecting the generated precipitate. In that case, the poor solvent to be used is not specifically limited. For example, methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, water and the like can be mentioned. The polyimide that has been poured into a poor solvent and precipitated is filtered, and then can be powdered by drying at normal temperature or under reduced pressure at normal temperature or under reduced pressure. The polyimide can also be refine | purified by repeating the operation which melt | dissolves the polyimide powder further in an organic solvent, and reprecipitates 2-10 times. When the impurities cannot be removed by a single precipitation recovery operation, it is preferable to perform this purification step. The molecular weight of the polyimide is not particularly limited, but is preferably 2,000 to 200,000, more preferably 4,000 to 50,000 in terms of weight average molecular weight from the viewpoint of ease of handling and stability of characteristics when a film is formed. 000.

<Polyimide or polyamic acid, terminal modification of polyamic acid ester>
The terminal of the polyimide or polyamic acid or polyamic acid ester used in the present invention may be modified. By using a terminal-modified polymer, solubility and coating properties can be improved. The terminal modification can be synthesized by adding an acid anhydride, a monoamine compound, an acid chloride compound, a monoisocyanate compound or the like when synthesizing a polyamic acid or a polyamic acid ester.

<Solvent>
The solvent contained in the liquid crystal aligning agent of the present invention contains (A) γ-valerolactone, (B) γ-butyrolactone, and (C) a compound represented by the following formula (c).

上記式（ｃ）中、Ｒ^１、Ｒ^３は、それぞれ独立して、水素原子、炭素数が１〜４、好ましくは１〜４の直鎖若しくは分岐のアルキル基、又はアセチル基である。また、Ｒ^２は、炭素数２又は３のアルカンジイル基である。ｎは１又は２である。

In the above formula (c), R ¹ and R ³ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, preferably 1 to 4 carbon atoms, or an acetyl group. R ² is an alkanediyl group having 2 or 3 carbon atoms. n is 1 or 2.

Preferable specific examples of R ¹ and R ^{3 in} the above formula (c) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group and the like. Specific examples of R ² include an ethylene group, a trimethylene group, and a propylene group.

  Specific examples of the compound represented by the above formula (c) include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2. -Propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, butyl cellosolve acetate, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-mono Ethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, diethylene glycol diethyl ether, diethylene glycol dimethyl ether Etc., and the like. Of these, butyl cellosolve, butyl cellosolve acetate, or 1-butoxy-2-propanol is preferable.

Regarding the contents of the above (A), (B), and (C) in the solvent contained in the liquid crystal aligning agent of the present invention, the γ-valerolactone of (A) is the linearity and dimensions of the coating film end. Since it contributes to stability, 20-75 mass% of the whole solvent is preferable, and 20-70 mass% is more preferable. Since (B) γ-butyrolactone contributes to dimensional stability, it is preferably 20 to 80% by mass, more preferably 20 to 70% by mass of the total solvent. The compound (C) is preferably 5 to 50% by mass, more preferably 5 to 40% by mass, and still more preferably 10 to 40% by mass of the total solvent.
The specific preferable content of (A), (B), and (C) is 20 to 75% by mass, more preferably 20 to 70% by mass, so that A is 100% by weight as a whole. , (B) is 20 to 75 mass%, more preferably 20 to 70 mass%, and (C) is selected from 5 to 60 mass%, more preferably 5 to 55 mass%.

  The liquid crystal aligning agent of the present invention may contain a solvent other than the above (A), (B), and (C) (hereinafter also referred to as other solvent). Specific examples of other solvents include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methylcaprolactam 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N, N-dimethylpropanamide, and the like. Multiple types may be used in combination. Among these, addition of N-methyl-2-pyrrolidone is preferable because the solubility of the polymer, the suppression of unevenness in the coating film surface, the linearity of the coating film edge, and the like are further improved. In this case, the content of N-methyl-2-pyrrolidone is preferably 3 to 55% by mass, more preferably 3 to 50% by mass with respect to the entire solvent. The specific preferable oil content is such that the content of (A) is 20 to 70% by mass, the content of (B) is 20 to 70% by mass, and the content of (C) so that the whole is 100% by weight. Is preferably 5 to 55% by mass, and the N-methyl-2-pyrrolidone content is preferably 3 to 55% by mass.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention is a composition containing the above polymer and solvent, and the content (concentration) of the polymer is appropriately changed depending on the thickness of the liquid crystal alignment film to be formed. However, it is preferably 1 to 5% by mass, particularly preferably 2% to 4% by mass, from the viewpoint of forming a uniform and defect-free coating film. The viscosity of the liquid crystal aligning agent of the present invention is preferably 5 to 20 mPa · s, particularly preferably 5 to 15 mPa · s, from the viewpoint of inkjet coating.
The content of the solvent in the liquid crystal aligning agent is selected in consideration of the above viscosity, and is preferably 95 to 99% by mass, and particularly preferably 96 to 98% by mass. In this case, a concentrated solution of the polymer may be prepared in advance and diluted when the liquid crystal aligning agent is used from the concentrated solution. When the content of the solvent is higher than 99% by mass, the film thickness of the liquid crystal alignment film becomes too small to obtain a good liquid crystal alignment film, and when the content of the solvent is lower than 95% by mass, in the case of inkjet, Ejectability from the head is degraded.

The liquid crystal aligning agent of this invention may contain various additives, such as a silane coupling agent and a crosslinking agent. The silane coupling agent is added for the purpose of improving the adhesion between the substrate on which the liquid crystal alignment agent is applied and the liquid crystal alignment film formed thereon. Existing silane coupling agents are added. If the addition amount of this silane coupling agent is too large, unreacted ones may adversely affect the liquid crystal orientation, and if it is too little, the effect on adhesion will not appear, so the solid content of the polymer 0.01 to 5.0% by weight is preferable, and 0.1 to 1.0% by weight is more preferable.
In addition, an imidization accelerator may be added to the liquid crystal aligning agent in order to efficiently advance imidization of the polyamic acid and polyamic acid ester when the coating film is baked. Existing imidation accelerators are used.

<Liquid crystal alignment film>
A liquid crystal aligning film can be obtained by applying the liquid crystal aligning agent of the present invention to a substrate, drying and baking. The substrate on which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, an acrylic substrate, a polycarbonate substrate such as a polycarbonate substrate, or the like can be used. Among these, it is preferable from the viewpoint of simplification of the process to use a substrate on which an ITO electrode or the like for driving a liquid crystal is formed. In the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used as long as only one substrate is used. In this case, a material that reflects light, such as aluminum, can also be used.

As a coating method of the liquid crystal aligning agent of the present invention, a spin coating method, a printing method, or the like can be used, but an inkjet method is particularly preferable. When applying the liquid crystal aligning agent of the present invention by an inkjet method to form a coating film, the uniformity of the film thickness within the coating surface, the linearity of the coating peripheral part, and the expansion width from the set dimensions during coating are suppressed. Thus, a coating film having excellent dimensional stability can be obtained. In the present invention, an existing inkjet apparatus can be used, and existing conditions can be used for coating. For example, the apparatus and conditions disclosed in International Publication WO2014-024885 are used.
The drying and baking steps after applying the liquid crystal aligning agent can be performed at any temperature and time, but usually 1 minute at 40 ° C. to 120 ° C. to sufficiently remove the contained organic solvent. It is dried for 10 to 10 minutes, and then baked at 150 to 300 ° C. for 5 to 120 minutes. Since the reliability of a liquid crystal display element may fall when the thickness of the coating film after baking is too thin, 5-300 nm is preferable, More preferably, it is 10-200 nm.

<Liquid crystal display element>
The obtained liquid crystal alignment film can be used for a liquid crystal display element after being subjected to alignment treatment by rubbing treatment, photo-alignment treatment, or the like, or without alignment treatment in vertical alignment applications. The liquid crystal display element is obtained by forming a liquid crystal cell by a known method using a substrate with a liquid crystal alignment film.
The manufacturing method of the liquid crystal cell is not particularly limited, but if an example is given, a pair of substrates on which the liquid crystal alignment film is formed has a liquid crystal alignment film surface inside, and the thickness is preferably 1 to 30 μm, more preferably A method is generally used in which a 2-10 μm spacer is placed and then the periphery is fixed with a sealant, and liquid crystal is injected and sealed. The method for enclosing the liquid crystal is not particularly limited, and examples thereof include a vacuum method of injecting liquid crystal after reducing the pressure inside the produced liquid crystal cell, and a dropping method of sealing after dropping the liquid crystal.

Examples Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The abbreviations used hereinafter and the measurement methods for each characteristic are as follows.
<Monomer>
1,3DMCBDE-Cl: dimethyl 1,3-bis (chlorocarbonyl) -1,3-dimethylcyclobutane-2,4-dicarboxylate BDA: 1,2,3,4-butanetetracarboxylic dianhydride,
PMDA: pyromellitic anhydride DADPA: 4,4′-diaminodiphenylamine Me-DADPA: N, N-bis (aminophenyl) -methylamine DBA: 3,5-diaminobenzoic acid p-PDA: p-phenylenediamine TDA : 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4, -tetrahydronaphthalene-1,2, -dicarboxylic anhydride

<Solvent>
NMP: N-methyl-2-pyrrolidone, BCS: butyl cellosolve BCA: butyl cellosolve acetate, GBL: γ-butyrolactone GVL: γ-valerolactone, DPM: dipropylene glycol monomethyl ether NEP: N-ethyl-2-pyrrolidone, PB: 1 -Butoxy-2-propanol

<Viscosity>
The viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) at a sample volume of 1.1 mL, a cone rotor TE-1 (1 ° 34 ′, R24), and a temperature of 25 ° C. .

<Molecular weight>
The molecular weight of the polymer is measured by a GPC (normal temperature gel permeation chromatography) apparatus, and the number average molecular weight (hereinafter also referred to as Mn) and the weight average molecular weight (hereinafter also referred to as Mw) as polyethylene glycol and polyethylene oxide converted values. Calculated.
GPC device: manufactured by Shodex (GPC-101)
Column: manufactured by Shodex (series of KD803 and KD805), column temperature: 50 ° C.
Eluent: N, N-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran) (THF) is 10 ml / L), flow rate: 1.0 ml / min Standard sample for preparing calibration curve: TSK standard polyethylene oxide (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, manufactured by Tosoh Corporation , 30,000), and polyethylene glycol manufactured by Polymer Laboratories (peak top molecular weight (Mp) of about 12,000, 4,000, 1,000). In order to avoid the overlapping of peaks, the measurement was performed by mixing four types of 900,000, 100,000, 12,000, and 1,000, and three types of 150,000, 30,000, and 4,000. Two samples of mixed samples are measured separately.

<Imidization rate>
20 mg of polyimide powder was put into an NMR sample tube, and 0.53 mL of deuterated dimethyl sulfoxide (DMSO-d6 and 0.05 mass% TMS (tetramethylsilane) mixture) was added and completely dissolved. This solution was measured for proton NMR at 500 MHz with an NMR measuring instrument (JNM-ECA500) manufactured by JEOL Datum.
The imidation rate was determined by the following formula using a proton peak derived from a structure that does not change before and after imidation as a reference peak.
Imidation rate (%) = (1−α · x / y) × 100
In the above formula, x is a proton peak integrated value derived from NH group of polyamic acid, y is a reference proton peak integrated value, α is a reference for one NH group proton of polyamic acid in the case of polyamic acid (imidation rate is 0%). The number ratio of protons.

(Synthesis Example 1)
In a 10 L (liter) separable flask equipped with a stirrer and a nitrogen inlet tube, 114.59 g (1.06 mol) of p-phenylenediamine and 44.68 g (0.12 mol) of DA-A were weighed, and 2972 g of NMP. And 210.1 g (2.66 mol) of pyridine was added and dissolved. Next, 359.85 and (1.11 mol) of 1,3DMCBDE-Cl were added while stirring this solution, and the mixture was reacted for 4 hours under water cooling. The obtained polyamic acid solution was diluted with 500 g of GBL. The solution was poured into 19103 ml of isopropanol while stirring, and the precipitated white precipitate was collected by filtration, then washed using 9551 ml of isopropanol in 5 portions, and dried to obtain white polyamic acid ester resin powder ( PWD-1) was obtained. The molecular weight of this polyamic acid ester was Mn = 5,182 and Mw = 30,115.
The polyamic acid ester resin powder (PWD-1) obtained above was dissolved in GBL to obtain a polyamic acid ester solution (PAE-1) having a solid content concentration of 10% by mass.

(Synthesis Example 2)
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.30 g (12.0 mmol) of p-phenylenediamine and 3.01 g (7.99 mmol) of DA-B are weighed, and 36.72 g of NMP is measured. , 29.38 g of GBL was added and dissolved while stirring while feeding nitrogen. While stirring this diamine solution, 5.70 g (19.0 mmol) of TDA was added, NMP was further added so that the solid content concentration would be 12% by weight, and the mixture was stirred at room temperature for 24 hours to be a polyamic acid solution (PAA-1 ) The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 285 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 8,042 and Mw = 18,958.

(Synthesis Example 3)
50 g of the polyamic acid solution (PAA-1) obtained in a 100 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube was taken, 16.67 g of NMP was added, and the mixture was stirred for 30 minutes. Next, 3.86 g of acetic anhydride and 1.0 g of pyridine were added and heated at 60 ° C. for 3 hours to perform chemical imidization. The obtained reaction solution was poured into 321 ml of methanol while stirring, and the deposited precipitate was collected by filtration, and subsequently washed using 321 ml of methanol in three portions. The obtained resin powder was dried at 60 ° C. for 12 hours to obtain a polyimide resin powder. The imidation ratio of this polyimide resin powder was 86%, the molecular weight was Mn = 6,920, and Mw = 12,721.
The polyimide resin powder obtained above was dissolved in GBL to obtain a polyimide solution (SPI-1) having a solid content concentration of 10% by mass.

(Synthesis Example 4)
In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.10 g (7.2 mmol) of DBA and 6.14 g (28.8 mmol) of Me-DADPA were weighed, 15.0 g of NMP, and GBL were measured. 42.0 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 6.42 g (32.4 mmol) of BDA, 0.62 g (2.8 mmol) of PMDA, and 18.0 g of GBL were added, and the mixture was stirred at room temperature for 24 hours to obtain a solid concentration. A polyamic acid solution (PAA-2) of 16% by mass and NMP / GBL = 2/8 was obtained. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 380.5 mPa · s. Moreover, the molecular weight of the obtained polyamic acid was Mn = 7,048 and Mw = 16,664.

Example 1
10. In a 200 ml sample tube containing a stirrer, 10.4 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 and the polyamic acid solution (PAA-2) obtained in Synthesis Example 4 8 g was measured, NMP 3.2 g, GBL 47.4 g, GVL 19.5 g, and BCA 9.7 g were added, and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-1). .

(Example 2)
10.4 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 and 9% of the polyamic acid solution (PAA-2) obtained in Synthesis Example 4 were placed in a 200 ml sample tube containing a stirrer. 0.8 g, NMP 3.2 g, GBL 27.0 g, GVL 40.0 g, and BCA 9.7 g were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-2). .

(Example 3)
10.4 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 and 9% of the polyamic acid solution (PAA-2) obtained in Synthesis Example 4 were placed in a 200 ml sample tube containing a stirrer. 0.8 g, NMP 2.3 g, GBL 7.5 g, GVL 60.4 g, and BCA 9.7 g were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-3). .

Example 4
10.4 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 and 9% of the polyamic acid solution (PAA-2) obtained in Synthesis Example 4 were placed in a 200 ml sample tube containing a stirrer. 0.8 g, NMP 2.3 g, GBL 32.8 g, GVL 19.5 g, and BCS 25.3 g were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-4). .

(Example 5)
In a 200 ml sample tube containing a stirrer, 26.0 g of the polyimide solution (SPI-1) obtained in Synthesis Example 3, 4.9 g of NMP, 39.9 g of GBL, 19.5 g of GVL, and 9.7 g of BCA was added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-5).

(Example 6)
In a 200 ml sample tube containing a stir bar, 26.0 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 was taken, 44.8 g of GBL, 19.5 g of GVL, and 9.9 of BCA. 7 g was added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (A-6).

(Example 7)
10.4 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 and 9.8 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 4 were added to a 200 ml sample tube containing a stirring bar. Weighing, 1.6 g of NMP, 1.6 g of NEP, 47.4 g of GBL, 19.5 g of GVL, 9.7 g of BCA, and stirring with a magnetic stirrer for 30 minutes, liquid crystal aligning agent (A-7) Got.

(Example 8)
10.4 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 and 9.8 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 4 were added to a 200 ml sample tube containing a stirring bar. Weighing, adding 3.2 g of NMP, 47.4 g of GBL, 19.5 g of GVL, 4.9 g of BCA, and 4.9 g of PB, stirring with a magnetic stirrer for 30 minutes, liquid crystal aligning agent (A-8) Got.

(Comparative Example 1)
In a 200 ml sample tube containing a stir bar, 2.6 g of the polyamic acid ester resin powder (PWD-1) obtained in Synthesis Example 1 is weighed, 87.7 g of GVL and 9.7 g of BCS are added, and magnetic. The liquid crystal aligning agent (B-1) was obtained by dissolving by stirring with a stirrer.

(Comparative Example 2)
10.4 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 and 9% of the polyamic acid solution (PAA-2) obtained in Synthesis Example 4 were placed in a 200 ml sample tube containing a stirrer. 0.8 g, 3.2 g of NMP, 66.9 g of GBL, and 9.7 g of BCS were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (B-2).

(Comparative Example 3)
10.4 g of the polyamic acid ester solution (PAE-1) obtained in Synthesis Example 1 and 9% of the polyamic acid solution (PAA-2) obtained in Synthesis Example 4 were placed in a 200 ml sample tube containing a stirrer. 0.8 g, 3.2 g of NMP, 71.5 g of GBL, and 4.9 g of DPM were added and stirred for 30 minutes with a magnetic stirrer to obtain a liquid crystal aligning agent (B-3).

[Method of forming and evaluating coating film]
After the liquid crystal aligning agent was filtered through a membrane filter having a pore size of 1.0 μm, it was applied to the substrate by the inkjet method using the apparatus and conditions described below, and then the preliminary drying and main baking described below were performed to form a coating film.
Inkjet coating device: HIS-200-1H (manufactured by Hitachi Plant Technology)
Application conditions: resolution 15 μm, stage speed 40 mm / sec, frequency 2000 Hz, pulse width 9.6 μsec, droplet volume 42 pl, pitch width 80 μm, pitch length 141 μm, applied voltage: 15 V, nozzle gap 0.5 mm
Substrate: A glass substrate with a size of 100 mm in length × 100 mm in width and with an ITO electrode on the entire surface of one side Application area: Application on a rectangular area with a set dimension of 72 mm in length × 80 mm in width on the ITO electrode surface of the substrate Drying time until drying: 60 seconds Pre-drying: 45 ° C / 2 minutes (hot plate)
Main firing: 230 ° C./30 minutes (IR oven)

<Method for evaluating dimensional stability>
The vertical width and the horizontal width of the coating film obtained above were measured with calipers, the difference from the set dimensions of 100 mm in length × 72 × 80 mm in width was determined, and the average value was calculated as “enlarged width”.

<In-plane uniformity evaluation method>
The in-plane surface of the coating film obtained above was observed visually and with an optical microscope, and “A”, a microscope that had no in-plane unevenness, linear unevenness, film thickness unevenness, etc. “B” indicates that the above-mentioned unevenness can be visually recognized by observation or visual observation.

<End straightness evaluation method>
Observe the end of the coating film obtained above with an optical microscope, the shape of the coating film end is a straight line "A", the coating film end of the meander is "B" and did.

[Evaluation results]
In the following Table 1, the evaluation result of the liquid crystal aligning agent obtained in Examples 1-6 and Comparative Examples 1-4 is shown.

Since the liquid crystal aligning agent of the present invention can provide a highly reliable liquid crystal display element in which defects such as display unevenness are suppressed, TN, STN, IPS, FFS, VA (MVA (Multi domain Vertical Alignment), optical vertical alignment) , PSA (including Polymer Sustained Alignment), etc.) and other liquid crystal display elements having a driving mode.
It should be noted that the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2015-025606 filed on February 12, 2015 are cited here as disclosure of the specification of the present invention. Incorporate.

Claims (10)

A liquid crystal aligning agent comprising at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and a solvent, wherein the solvent is (A) γ-valerolactone, (B) A liquid crystal aligning agent comprising γ-butyrolactone and (C) a compound represented by the following formula (c).

(Wherein R ¹ and R ³ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an acetyl group, R ² is an alkanediyl group having 2 or 3 carbon atoms, and n is 1 or 2)   The liquid crystal aligning agent of Claim 1 whose content of (A) is 20-75 mass% of the whole solvent.   The content of (A) is 20 to 75 mass%, the content of (B) is 20 to 75 mass%, and the content of (C) is 5 to 60 mass% with respect to the entire solvent. Liquid crystal aligning agent as described in.   The liquid crystal aligning agent of any one of Claims 1-3 in which a solvent contains N-methyl-2- pyrrolidone further.   The content of (A) is 20 to 70% by mass, the content of (B) is 20 to 70% by mass, the content of (C) is 5 to 55% by mass, and N-methyl-2, based on the whole solvent. The liquid crystal aligning agent of Claim 4 whose content of -pyrrolidone is 3-55 mass%.   Content of a polymer is 1-5 mass%, The liquid crystal aligning agent of any one of Claims 1-5.   The liquid crystal aligning agent of any one of Claims 1-6 for apply | coating to a board | substrate by the inkjet method.   The liquid crystal aligning film obtained from the liquid crystal aligning agent of any one of Claims 1-7.   The manufacturing method of the liquid crystal aligning film which apply | coats the liquid crystal aligning agent of any one of Claims 1-6 with the inkjet method.   The liquid crystal display element provided with the liquid crystal aligning film of Claim 8.