CN109196412B

CN109196412B - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: CN109196412B
Application number: CN201780033849.0A
Authority: CN
Inventors: 中原翔一朗; 桥本淳; 石川和典; 李柱永
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2016-03-31
Filing date: 2017-03-30
Publication date: 2021-08-24
Anticipated expiration: 2037-03-30
Also published as: JP6866892B2; TW201809231A; KR20180124127A; CN109196412A; TWI823833B; JPWO2017170943A1; WO2017170943A1; KR102292494B1

Abstract

Provided are a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal display element, wherein the poor coating of the alignment film and the poor display unevenness of the liquid crystal display element caused by the influence of a wiring structure or C/H can be suppressed, the viscosity of the liquid crystal aligning agent is reduced, and the resin component ratio is increased. A liquid crystal aligning agent, comprising: at least 1 polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide compound thereof; and a solvent containing the following solvent A, solvent B and solvent C. Solvent A: at least 1 selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, gamma-butyrolactone, and dimethylimidazolidinone. Solvent B: dipropylene glycol dimethyl ether. Solvent C: a compound (R) represented by the following formula (a)₁、R₂Each independently is a linear or branched alkyl group having 1 to 8 carbon atoms, R₁And R₂The total number of carbon atoms of (a) is 4 or more. )

Description

Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Technical Field

The present invention relates to a liquid crystal aligning agent suitable for an inkjet film forming method and having high dimensional stability at the time of coating, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element provided with the liquid crystal alignment film.

Background

As the liquid crystal alignment film, a so-called polyimide-based liquid crystal alignment film obtained by applying a liquid crystal alignment agent containing a polyimide precursor such as polyamic acid (also referred to as polyamic acid) or a solution of a soluble polyimide as a main component and firing the applied liquid crystal alignment agent is widely used.

As a method for forming the liquid crystal alignment film, spin coating, dip coating, flexographic printing, and the like are generally known. In practice, flexographic printing is often used. However, the flexible printing has the following problems: various resin plates are required according to the variety of the liquid crystal panel; the plate is complicated to replace in the manufacturing process; the film must be formed on the dummy substrate to stabilize the film forming process, and the plate must be formed, which causes an increase in the manufacturing cost of the liquid crystal display panel.

Therefore, an ink jet method has attracted attention as a method for forming a liquid crystal alignment film without using a printing plate. The ink jet method is a method in which fine droplets are dropped on a substrate and a film is formed by wet spreading of the liquid. Since the printed pattern can be freely set without using a printing plate, the manufacturing process of the liquid crystal display element can be simplified. Further, there is an advantage that film formation on a dummy substrate necessary for flexographic printing is not necessary, and waste of the coating liquid is small. The ink jet method is expected to reduce the cost of the liquid crystal panel and improve the production efficiency.

The liquid crystal alignment film formed by the ink jet method is required to have small film thickness unevenness inside the coated surface and high film formation accuracy in the coated peripheral portion. In general, in a liquid crystal alignment film formed by an ink jet method, the uniformity of film thickness in the coating surface and the film formation accuracy in the peripheral portion of the coating surface have a trade-off relationship. That is, in general, the dimensional stability of the coating peripheral portion of a material having high in-plane uniformity is low, and the film protrudes from the set size. On the other hand, the uniformity in the coating surface of the material having the coating peripheral portion in a straight line is low.

In order to improve the film formation accuracy of the coating periphery, a method of limiting the alignment film to a predetermined range by using a special structure has been proposed (see patent documents 1 to 3). However, these methods have a difficulty in requiring a special structure.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2004-361623

Patent document 2: japanese patent laid-open No. 2008-145461

Patent document 3: japanese patent application laid-open No. 2010-281925

Disclosure of Invention

Problems to be solved by the invention

In recent years, with the increase in definition of liquid crystal display elements, TFT design of multilayer wiring has become mainstream. In TFT design, a contact hole (also referred to as C/H) is formed in a substrate to connect a lower layer wiring and an upper layer wiring. Accordingly, the spreading property of the liquid is easily hindered when the liquid crystal aligning agent is applied due to the influence of the wiring structure and C/H. As a result, dot-like unevenness or stripe-like unevenness occurs around the C/H or other portions, and the thickness of the alignment film becomes uneven, and the display of the liquid crystal display element may become uneven.

In addition, the liquid crystal aligning agent used in the ink jet method is required to have a low viscosity in order to stably discharge the aligning agent from the ink jet nozzle, and accordingly, the resin component ratio in the liquid crystal aligning agent may be set to be small. On the other hand, in order to make the thickness of the peripheral portion of the liquid crystal alignment film uniform and to suppress the width of the liquid crystal alignment film, it is necessary to increase the resin component ratio in the liquid crystal alignment agent while maintaining the low viscosity of the liquid crystal alignment agent, and such a liquid crystal alignment agent is demanded.

In view of the above problems, the present invention provides a liquid crystal aligning agent and a liquid crystal alignment film using the same, which can suppress the film formation failure of a liquid crystal alignment film and the failure of uneven display of a liquid crystal display element due to the influence of a wiring structure or C/H, and can reduce the viscosity of the liquid crystal aligning agent and increase the resin component ratio.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above problems, and as a result, the present invention has been completed.

The gist of the present invention is a liquid crystal aligning agent, comprising: at least 1 polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide compound thereof; and a solvent containing a solvent belonging to the following groups A, B and C.

Group A: at least 1 solvent selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), gamma-butyrolactone (GBL) and 1, 3-Dimethylimidazolidinone (DMI)

Group B: dipropylene glycol dimethyl ether (DME)

Group C: a solvent containing a compound represented by the following formula (a)

R₁、R₂Each independently is a linear or branched alkyl group having 1 to 8 carbon atoms. Wherein R is₁And R₂The total number of carbon atoms of (a) is 4 or more.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a polyimide-based liquid crystal aligning agent, a liquid crystal alignment film using the same, and a liquid crystal display element can be obtained, which can suppress a film formation failure of a liquid crystal alignment film and a failure of uneven display of a liquid crystal display element due to the influence of a wiring structure or C/H, and which can maintain a low viscosity and have a high resin component ratio, and thus are suitable for film formation by an ink jet method.

Detailed Description

The liquid crystal aligning agent of the present invention contains: at least 1 polymer (hereinafter, also referred to as a specific polymer) selected from the group consisting of a polyimide precursor and a polyimide as an imide compound thereof; and a solvent (hereinafter, also referred to as a specific solvent) containing the solvent a, the solvent B, and the solvent C described below.

< specific solvent >

The solvent contained in the liquid crystal aligning agent of the present invention contains the above-mentioned solvent a, solvent B and solvent C, and each of them will be described below.

< solvent A >

The solvent a is at least 1 solvent selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), gamma-butyrolactone (GBL), and 1, 3-Dimethylimidazolidinone (DMI). The solvent A dissolves the polymer in the liquid crystal aligning agent.

Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ -butyrolactone (GBL) is preferable, and N-methyl-2-pyrrolidone (NMP) or γ -butyrolactone (GBL) is more preferable.

In the liquid crystal aligning agent of the present invention, the content of the solvent a is preferably 20 to 90 mass%, more preferably 30 to 80 mass%, and further preferably 50 to 80 mass% with respect to the total mass of the liquid crystal aligning agent.

< solvent B >

Solvent B is dipropylene glycol dimethyl ether (DME). The solvent B is a solvent contributing to improvement in coating uniformity of the liquid crystal aligning agent and reduction in viscosity.

In the liquid crystal aligning agent of the present invention, the content of the solvent B is preferably 5 to 50% by mass, and more preferably 10 to 50% by mass, based on the total mass of the liquid crystal aligning agent.

< solvent C >

The solvent C is composed of a compound represented by the following formula (a).

In the formula (a), R₁、R₂Each independently a linear or branched alkyl group having 1 to 8 carbon atoms, preferably 3 to 8 carbon atoms, more preferably 3 to 6 carbon atoms. Wherein R is₁And R₂The total number of carbon atoms of (a) is 4 or more, preferably 5 to 12.

The solvent C represented by the formula (a) is specifically exemplified by the following a-1 to a-48, but is not limited thereto.

Among them, the solvent C is preferably a-22, a-13 to a-21, a-24, a-26, a-27, a-31, a-34, a-37 or a-38, more preferably a-22 or a-37, from the viewpoint of availability and practicality.

In the liquid crystal aligning agent of the present invention, the content of the solvent C is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total mass of the liquid crystal aligning agent.

The total content of the solvent B and the solvent C is preferably 20 to 50% by mass, more preferably 20 to 40% by mass, based on the total mass of the liquid crystal aligning agent. In this case, the content of the solvent B is preferably larger than the content of the solvent C, and more preferably 1 to 20 mass% larger than the content of the solvent C.

The liquid crystal aligning agent of the present invention may contain a solvent other than the specific solvent. Examples thereof include butyl cellosolve, 1-butoxy-2-propanol, butyl cellosolve acetate, dipropylene glycol monomethyl ether, diacetone alcohol, diethylene glycol diethyl ether, diisoamyl ether, propylene glycol diacetate, diisobutyl ketone, ethyl carbitol, dipropylene glycol dimethyl ether, and γ -valerolactone. The amount of the solvent other than the specific solvent is preferably 50% by mass or less, more preferably 20% by mass or less, based on the total mass of the liquid crystal aligning agent.

< specific Polymer >

The polyimide precursor as the specific polymer contained in the liquid crystal aligning agent of the present invention preferably has a structure represented by the following formula (1).

In the formula (1), X₁Is a tetravalent organic radical derived from a tetracarboxylic acid derivative. Y is₁Is a divalent organic group derived from a diamine. R₁Is a hydrogen atom or an alkylene group having 1 to 5 carbon atoms. From the viewpoint of easiness of the imidization reaction during heatingHair, R₁Preferably a hydrogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom or a methyl group.

A₁And A₂Each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms. From the viewpoint of liquid crystal alignment, A₁And A₂Preferably a hydrogen atom, or a methyl group.

Hereinafter, each component as a raw material for producing the polyimide precursor will be described.

< diamine >

The diamine component used in the production of the polyimide precursor is not particularly limited, and the diamine as a raw material of the polyimide precursor represented by the above formula (1) is represented by the following formula (2).

In the formula (2), A₁And A₂Also included are preferred examples and A in the above formula (1)₁And A₂Are the same definition. If example Y₁The following (Y-1) to (Y-170) may be mentioned.

Wherein n is an integer of 1 to 6, and Me is a methyl group.

Among them, (Y-7), (Y-8), (Y-16), (Y-17), (Y-18), (Y-20), (Y-21), (Y-22), (Y-28), (Y-35), (Y-38), (Y-43), (Y-48), (Y-64), (Y-66), (Y-71), (Y-72), (Y-76), (Y-77), (Y-80), (Y-81), (Y-82), (Y-83), (Y156), (Y-159), (Y-160), (Y-161), (Y-162) (Y-168), (Y-169) or (Y-170) are preferable, and (Y-7) and (Y-17) are particularly preferable, (Y-8), (Y-16), (Y-17), (Y-18), (Y-21), (Y-22), (Y-28), (Y-38), (Y-64), (Y-66), (Y-72), (Y-76), (Y-81), (Y156), (Y-159), (Y-160), (Y-161), (Y-162) (Y-168), (Y-169), or (Y-170).

< tetracarboxylic acid derivative >

The tetracarboxylic acid derivative used in the production of the polyimide precursor is not particularly limited, and the tetracarboxylic acid derivative component as a raw material of the polyimide precursor represented by the formula (1) includes not only tetracarboxylic dianhydride but also tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide as a derivative thereof.

The tetracarboxylic dianhydride or its derivative is preferably represented by the following formula (3).

In the formula (3), X₁The organic group is a tetravalent organic group having an alicyclic structure, and the structure thereof is not particularly limited. Specific examples thereof include the following formulae (X1-1) to (X1-44).

Formula (X1-1) _ E(X1-4) wherein R is₃～R₂₃Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a fluorine-containing monovalent organic group having 1 to 6 carbon atoms, or a phenyl group. From the viewpoint of liquid crystal alignment, R₃～R₂₃Preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom or a methyl group.

Specific examples of the formula (X1-1) include the following formulae (X1-1-1) to (X1-1-6). From the viewpoint of liquid crystal alignment properties and sensitivity to photoreaction, (X1-1-1) is particularly preferred.

The tetracarboxylic dianhydride and its derivative, which are raw materials for the polyimide precursor and the polyimide of the present invention, preferably contain 60 to 100 mol% of the tetracarboxylic dianhydride represented by the formula (3) or its derivative, based on 1 mol of the total tetracarboxylic dianhydride and its derivative. In order to obtain a liquid crystal alignment film having good liquid crystal alignment properties, it is more preferably 80 to 100 mol%, and still more preferably 90 to 100 mol%.

< polyimide precursor >

< method for producing polyamic acid ester >

A polyamic acid ester which is one of the polyimide precursors used in the present invention can be produced by the following method (1), (2) or (3).

(1) Case of production from Polyamic acid

The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from a tetracarboxylic dianhydride and a diamine.

Specifically, the polyamic acid can be synthesized by reacting a polyamic acid with an esterifying agent in the presence of an organic solvent at-20 to 150 ℃, preferably 0 to 50 ℃, for 30 minutes to 24 hours, preferably 1 to 4 hours.

The esterification agent is preferably easily removable by purification, and examples thereof include N, N-dimethylformamide dimethyl acetal, N-dimethylformamide diethyl acetal, N-dimethylformamide dipropyl acetal, N-dimethylformamide dineopentyl butyl acetal, N-dimethylformamide di-tert-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, and 4- (4, 6-dimethoxy-1, 3, 5-triazin-2-yl) -4-methylmorpholinium chloride. The amount of the esterifying agent to be used is preferably 2 to 6 molar equivalents based on 1 mole of the repeating unit of the polyamic acid.

The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ -butyrolactone in view of the solubility of the polymer, and 1 kind or a mixture of 2 or more kinds thereof may be used. The concentration of the polymer in the reaction solution is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that the polymer is not easily precipitated and a polymer is easily obtained.

(2) Produced by reacting a tetracarboxylic acid diester diacid chloride with a diamine

The polyamic acid ester can be made from a tetracarboxylic acid diester diacid chloride and a diamine. Specifically, the tetracarboxylic acid diester diacid chloride can be produced by reacting a tetracarboxylic acid diester diacid chloride with a diamine in the presence of a base and an organic solvent at-20 ℃ to 150 ℃, preferably 0 ℃ to 50 ℃, for 30 minutes to 24 hours, preferably 1 to 4 hours.

Pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used as the base, and pyridine is preferable in order to allow the reaction to proceed smoothly. The amount of the base to be used is preferably 2 to 4 times by mol based on the tetracarboxylic diester diacid chloride, from the viewpoint of ease of removal and availability of the polymer.

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 the polymer, and 1 or 2 or more thereof may be used in combination. The polymer concentration in the reaction solution is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that polymer precipitation is not likely to occur and a polymer is easily obtained. In order to prevent hydrolysis of the tetracarboxylic acid diester diacid chloride, it is preferable that the solvent used in the synthesis of the polyamic acid ester be dehydrated as much as possible, and that the mixing of the external gas be prevented in a nitrogen atmosphere.

(3) Production of polyamic acid esters from tetracarboxylic acid diesters and diamines

The polyamic acid ester can be produced by polycondensing a tetracarboxylic acid diester with a diamine. Specifically, the tetracarboxylic acid diester can be produced by reacting a tetracarboxylic acid diester with a diamine in the presence of a condensing agent, a base and an organic solvent at 0 to 150 ℃, preferably 0 to 100 ℃, for 30 minutes to 24 hours, preferably 3 to 15 hours.

As the condensing agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N ' -carbonyldiimidazole, dimethoxy-1, 3, 5-triazinylmethyl morpholinium, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium hexafluorophosphate, (2, 3-dihydro-2-thio-3-benzoxazolyl) diphenyl phosphonate, and the like can be used. The amount of the condensing agent to be added is preferably 2 to 3 times by mol based on the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base to be used is preferably 2 to 4 times by mole relative to the diamine component, from the viewpoint of ease of removal and ease of obtaining a polymer.

In addition, in the above reaction, the reaction proceeds efficiently by adding a lewis acid as an additive. As the lewis acid, lithium halide such as lithium chloride or lithium bromide is preferable. The amount of the Lewis acid added is preferably 0 to 1.0 mol per mol of the diamine component.

Among the above-mentioned 3 methods for producing polyamic acid esters, the above-mentioned (1) or (2) method is particularly preferable in order to obtain a polyamic acid ester having a high molecular weight.

The solution of polyamic acid ester obtained in the above-described manner can be poured into a poor solvent while sufficiently stirring to precipitate a polymer. The polyamic acid ester is precipitated several times, washed with a poor solvent, and dried at room temperature or under heating to obtain a purified polyamic acid ester powder. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, and the like.

< method for producing Polyamic acid >

The polyamic acid as a polyimide precursor used in the present invention can be produced by the following method.

Specifically, it can be synthesized by reacting tetracarboxylic dianhydride with diamine in the presence of an organic solvent at-20 to 150 ℃, preferably 0 to 50 ℃, for 30 minutes to 24 hours, preferably 1 to 12 hours.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ -butyrolactone, from the viewpoint of solubility of the monomer and the polymer, and 1 or 2 or more thereof may be used in combination. The concentration of the polymer is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that the polymer is not easily precipitated and a polymer is easily obtained.

The polyamic acid obtained in the above-described manner can be recovered by pouring the reaction solution into a poor solvent while sufficiently stirring the reaction solution to precipitate a polymer. Further, precipitation is performed several times, and after washing with a poor solvent, drying at room temperature or under heating is performed, whereby a powder of a purified polyamic acid can be obtained. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, and the like.

< method for producing polyimide >

The polyimide used in the present invention can be produced by imidizing the polyamic acid ester or polyamic acid. In the production of a polyimide from a polyamic acid ester, chemical imidization by adding a basic catalyst to the polyamic acid ester solution or a polyamic acid solution obtained by dissolving a polyamic acid ester resin powder in an organic solvent is simple. Chemical imidization is preferred because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is less likely to decrease during the imidization.

The chemical imidization can be carried out by stirring the polyamic acid ester to be imidized in an organic solvent in the presence of a basic catalyst. As the organic solvent, a solvent used in the polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, triethylamine is preferable because it has a sufficient basicity for the reaction to proceed.

The temperature for the imidization reaction is-20 to 140 ℃ and preferably 0 to 100 ℃, and the imidization reaction can be carried out for a reaction time of 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times of the amount of the amide ester group. The imidization ratio of the obtained polymer can be controlled by adjusting the amount of the catalyst, the temperature, and the reaction time. Since the added catalyst and the like remain in the solution after the imidization reaction, it is preferable to recover the obtained imidized polymer and redissolve it in an organic solvent to obtain the liquid crystal aligning agent of the present invention.

In the production of a polyimide from a polyamic acid, chemical imidization by adding a catalyst to a solution of the polyamic acid obtained by the reaction of a diamine component and a tetracarboxylic dianhydride is simple. Chemical imidization is preferred because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is less likely to decrease during the imidization.

Chemical imidization can be performed by stirring a polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, a solvent used in the polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has a suitable basicity for advancing the reaction. The acid anhydride includes acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like, and among these, acetic anhydride is preferable because purification after completion of the reaction is easy.

The temperature for the imidization reaction is-20 to 140 ℃ and preferably 0 to 100 ℃, and the imidization reaction can be carried out for a reaction time of 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 times, preferably 2 to 20 times, the amount of the acid anhydride is 1 to 50 times, preferably 3 to 30 times, the amount of the acid amide group. The imidization ratio of the obtained polymer can be controlled by adjusting the amount of the catalyst, the temperature, and the reaction time.

Since the catalyst to be added remains in the polyamic acid ester or the solution after the imidization of the polyamic acid, it is preferable to recover the obtained imidized polymer by the following means and redissolve it in an organic solvent to obtain the liquid crystal aligning agent of the present invention.

The polyimide solution obtained in the above-described manner can be poured into a poor solvent while sufficiently stirring to precipitate a polymer. The polyamic acid ester is precipitated several times, washed with a poor solvent, and dried at room temperature or under heating to obtain a purified polyamic acid ester powder.

The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

< liquid Crystal alignment agent >

The liquid crystal aligning agent of the present invention is in the form of a solution in which a specific polymer is dissolved in a solvent containing a specific solvent. The molecular weight of the polyimide precursor and the polyimide described in the present invention is preferably 2000 to 500000, more preferably 5000 to 300000, and further preferably 10000 to 100000 in terms of weight average molecular weight. The number average molecular weight is preferably 1000 to 250000, more preferably 2500 to 150000, and further preferably 5000 to 50000.

The concentration of the polymer of the liquid crystal aligning agent used in the present invention can be appropriately changed by setting the thickness of a coating film to be formed, and is preferably 1 wt% or more from the viewpoint of forming a uniform and defect-free coating film, and is preferably 10 wt% or less from the viewpoint of the storage stability of the solution.

< other solvents >

The liquid crystal aligning agent of the present invention may contain a solvent (hereinafter, also referred to as another solvent) other than the above-mentioned solvents A, B and C. The other solvent may include a solvent (also referred to as a good solvent) for dissolving the polyimide precursor and the polyimide, and a solvent (also referred to as a poor solvent) for improving the film coatability and surface smoothness of the liquid crystal alignment film when the liquid crystal alignment agent is applied.

Specific examples of other solvents are given below, but the examples are not limited thereto.

Examples of the good solvent include N, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N, N-dimethylpropionamide (IPME), 4-hydroxy-4-methyl-2-pentanone, and the like.

Specific examples of the poor solvent include ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentanol, tert-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1, 2-ethanediol, 1-butanol, 2-butanol, isobutanol, 3-butanol, 2-methyl-2-butanol, 2-pentanol, 1-hexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1, 2-ethanediol, and mixtures thereof, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 2-methyl-2, 4-pentanediol, 2-ethyl-1, 3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1, 2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 1, 3-butanediol, 1, 4-dioxane, 1, 5-dimethyl ether, ethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl ether, 2-diethyl ether, 2-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 2-ethyl butyl acetate, 2, n, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, butyl cellosolve, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, 1-butoxy-2-propanol, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, diethylene glycol monoethyl ether acetate, diacetone alcohol, propylene glycol diacetate, diisoamyl ether, diethylene glycol monobutyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol methyl ether acetate, ethylene glycol methyl ether acetate, propylene glycol methyl ether, propylene glycol mono-ethyl ether acetate, propylene glycol mono-ethyl ether acetate, propylene glycol mono-butyl ether acetate, propylene glycol mono-ethyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, diisobutyl ketone, ethyl carbitol, and the like.

Examples of the poor solvent include solvents represented by the following formulas [ D-1] to [ D-3 ].

Formula [ D-1]In (D)¹Represents an alkyl group having 1 to 3 carbon atoms of the formula [ D-2 ]]In (D)²Represents an alkyl group having 1 to 3 carbon atoms, formula [ D-3]]In (D)³Represents an alkyl group having 1 to 4 carbon atoms.

The liquid crystal aligning agent of the present invention may comprise: a crosslinkable compound having an epoxy group, an isocyanate group, an oxetanyl group or a cyclocarbonate group; a crosslinkable compound having at least 1 substituent selected from the group consisting of a hydroxyl group, a hydroxyalkyl group and a lower alkoxyalkyl group; or a crosslinkable compound having a polymerizable unsaturated bond. These substituents and polymerizable unsaturated bonds must have 2 or more in the crosslinkable compound.

Examples of the crosslinkable compound having an epoxy group or an isocyanate group include bisphenol acetone glycidyl ether, phenol novolac epoxy resin, cresol novolac epoxy resin, triglycidyl isocyanurate, tetraglycidyl aminodiphenylene (tetraglycidyl aminodiphenylene), tetraglycidyl m-xylylenediamine, tetraglycidyl-1, 3-bis (aminoethyl) cyclohexane, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, bisphenol hexafluoroacetyl diglycidyl ether, 1, 3-bis (1- (2, 3-epoxypropoxy) -1-trifluoromethyl-2, 2, 2-trifluoromethyl) benzene, 4-bis (2, 3-epoxypropoxy) octafluorobiphenyl, triglycidyl-p-aminophenol, tetraglycidyl m-xylylenediamine, 2- (4- (2, 3-epoxypropoxy) phenyl) -2- (4- (1, 1-bis (4- (2, 3-epoxypropoxy) phenyl) ethyl) phenyl) propane or 1, 3-bis (4- (1- (4- (2, 3-epoxypropoxy) phenyl) -1-methylethyl) phenyl) ethyl) phenoxy) -2-propanol, etc.

The crosslinkable compound having an oxetanyl group is a compound having at least 2 oxetanyl groups represented by the following formula [4A ].

Specifically, examples of the crosslinkable compound include crosslinkable compounds represented by the formulae [4a ] to [4k ] described in International publication No. WO2011/132751 (publication 2011.10.27) on pages 58 to 59.

The crosslinkable compound having a cyclocarbonate group is a crosslinkable compound having at least 2 cyclocarbonate groups represented by the following formula [5A ].

Specifically, examples of the crosslinkable compound include crosslinkable compounds represented by the formulae [5-1] to [5-42] described in International patent publication No. WO2012/014898 (publication No. 2012.2.2) on pages 76 to 82.

Examples of the crosslinkable compound having at least 1 substituent selected from the group consisting of a hydroxyl group and an alkoxy group include amino resins having a hydroxyl group or an alkoxy group, such as melamine resin, urea resin, guanamine resin, glycoluril-formaldehyde resin, succinamide-formaldehyde resin, and ethyleneurea-formaldehyde resin. Specifically, a melamine derivative, a benzoguanamine derivative, or glycoluril in which the hydrogen atom of the amino group is substituted with a hydroxymethyl group, an alkoxymethyl group, or both of them can be used. The melamine derivative or benzoguanamine derivative may be a 2-mer or a 3-mer. They preferably have an average of 3 to 6 hydroxymethyl or alkoxymethyl groups per 1 triazine ring.

Examples of the melamine derivative or benzoguanamine derivative include commercially available MX-750 substituted with an average of 3.7 methoxymethyl groups per 1 triazine ring, MW-30 substituted with an average of 5.8 methoxymethyl groups per 1 triazine ring (see above, manufactured by Sanwa Chemical Co., Ltd.), methoxymethylated melamines such as Cymel300, 301, 303, 350, 370, 771, 325, 327, 703, 712, etc., methoxymethylated butoxymethylated melamines such as Cymel235, 236, 238, 212, 253, 254, etc., butoxymethylated melamines such as Cymel506, 508, etc., carboxymethylated isobutoxymethylated melamine such as Cymel1141, methoxymethylated ethoxymethylated benzoguanamine such as Cymel1123, etc., methoxymethylated butoxymethylated benzoguanamine such as Cymel 3-10, etc., butoxymethylated benzoguanamine such as Cymel1128, methoxymethylated benzoguanamine such as Cymel1125-80, etc. (these compounds are exemplified by, mitsui Cyanamid co., ltd). Examples of glycolurils include butoxymethylated glycolurils such as Cymel1170, hydroxymethylated glycolurils such as Cymel1172, and methoxyhydroxymethylated glycolurils such as Powderlink 1174.

Examples of the benzene or phenol compound having a hydroxyl group or an alkoxy group include 1,3, 5-tris (methoxymethyl) benzene, 1,2, 4-tris (isopropoxymethyl) benzene, 1, 4-bis (sec-butoxymethyl) benzene, and 2, 6-dihydroxymethyl-p-tert-butylphenol.

More specifically, crosslinkable compounds of the formulae [6-1] to [6-48] described in International publication No. WO2011/132751 (publication 2011.10.27) at pages 62 to 66 can be mentioned.

Examples of the crosslinkable compound having a polymerizable unsaturated bond include crosslinkable compounds having 3 polymerizable unsaturated groups in the molecule, such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, tris (meth) acryloyloxyethoxytrimethylpropane, and glycerol polyglycidyl ether poly (meth) acrylate; further, the acrylic resin composition may further contain a crosslinkable group having 2 polymerizable unsaturated groups in the molecule, such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide bisphenol a type di (meth) acrylate, propylene oxide bisphenol type di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, phthalic acid diglycidyl ester di (meth) acrylate, or hydroxypivalyl hydroxypivalate di (meth) acrylate A compound; and crosslinkable compounds having 1 polymerizable unsaturated group in the molecule, such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycerol mono (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate, and N-methylol (meth) acrylamide.

Further, a compound represented by the following formula [7A ] can also be used.

(formula [7A ]]In, E₁Represents a group selected from the group consisting of a cyclohexane ring, a bicyclohexane ring, a benzene ring, a biphenyl ring, a terphenyl ring, a naphthalene ring, a fluorene ring, an anthracene ring or a phenanthrene ring, E₂Is represented by a formula [7a ] selected from]Or formula [7b]N represents an integer of 1 to 4).

The number of the crosslinkable compounds used in the liquid crystal aligning agent of the present invention may be 1, or 2 or more in combination.

The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is preferably 0.1 to 150 parts by mass with respect to 100 parts by mass of the total polymer components. Among them, 0.1 to 100 parts by mass is preferable in order to promote the crosslinking reaction and to exhibit the desired effect. More preferably 1 to 50 parts by mass.

The liquid crystal aligning agent of the present invention may contain a compound that improves the uniformity of the film thickness and surface smoothness of the liquid crystal alignment film when the liquid crystal aligning agent is applied.

Examples of the compound for improving the uniformity of the film thickness and the surface smoothness of the liquid crystal alignment film include a fluorine-based surfactant, a silicone-based surfactant, and a nonionic surfactant.

Specific examples thereof include Ftop EF301, EF303, EF352 (see above, Tochem Products Co., Ltd.), MegaFac F171, F173, R-30 (see above, Dainippon Ink and Chemicals, Inc.), Fluorad FC430, FC431 (see above, Sumitomo 3M Co., Ltd.), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (see above, Asahi Niger Co., Ltd.).

The amount of the surfactant to be used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of the total polymer components contained in the liquid crystal aligning agent.

Further, as a compound which promotes charge transfer in the liquid crystal alignment film and promotes charge release of the device, a nitrogen-containing heterocyclic amine represented by the formulae [ M1] to [ M156] described on pages 69 to 73 of international publication No. WO2011/132751 (2011.10.27) may be added to the liquid crystal alignment agent. The amine may be added directly to the liquid crystal aligning agent, preferably as a solution having a concentration of 0.1 to 10 mass%, preferably 1 to 7 mass%. The solvent is not particularly limited as long as it dissolves the specific polymer.

The liquid crystal aligning agent of the present invention may contain a silane coupling agent for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, an imidization accelerator for the purpose of heating to imidize the polyimide precursor efficiently when the coating film is fired, and the like, in addition to the above-mentioned poor solvent, crosslinkable compound, compound for improving the uniformity of film thickness and surface smoothness of the resin coating film or the liquid crystal alignment film, and compound for promoting charge escape.

< liquid Crystal alignment film & liquid Crystal display device >

The liquid crystal alignment film of the present invention is obtained by applying the liquid crystal alignment agent to a substrate, drying the applied liquid crystal alignment agent, and firing the dried liquid crystal alignment agent. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as a glass substrate, a silicon nitride substrate, an acrylic substrate, or a polycarbonate substrate may be used. In this case, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed, from the viewpoint of simplification of the process. In the reflective liquid crystal display element, an opaque material such as a silicon wafer may be used as the substrate on only one side, and a material that reflects light such as aluminum may be used as the electrode in this case.

The method of applying the liquid crystal aligning agent is generally industrially performed by screen printing, offset printing, flexo printing, inkjet method, or the like. As other coating methods, a dipping method, a roll coater method, a slit coater method, a spinner method, a spray method, or the like are known.

Among them, the liquid crystal aligning agent of the present invention can realize a low viscosity of the liquid crystal aligning agent while maintaining a high content ratio of the polymer and a high molecular weight of the polymer as described above, and thus can be suitably used for coating by an ink jet method and a film forming method.

After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated by a heating means such as a hot plate, a thermal cycle oven, or an IR (infrared ray) oven to form a liquid crystal alignment film. The drying and firing steps after the application of the liquid crystal aligning agent can be performed at any temperature and for any time. In general, in order to sufficiently remove the solvent contained, there are listed: firing at 50-120 ℃ for 1-10 minutes, and then firing at 150-300 ℃ for 5-120 minutes. If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the device may be lowered by the liquid crystal, and therefore, the thickness is preferably 5 to 300nm, more preferably 10 to 200 nm.

The liquid crystal aligning agent of the present invention can be used as a liquid crystal alignment film by applying it to a substrate, baking it, and then performing alignment treatment such as rubbing treatment or photo-alignment treatment, or by not performing alignment treatment for vertical alignment. The alignment treatment such as brushing treatment and photo-alignment treatment may be performed by a known method or apparatus.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described. Note that the liquid crystal display element may be an active matrix liquid crystal display element in which a switching element such as a TFT (thin film transistor) is provided in each pixel portion constituting an image display.

Specifically, a transparent glass substrate is prepared, and a common electrode is provided on one substrate and a segment electrode is provided on the other substrate. These electrodes may be ITO electrodes, for example, and are patterned to enable desired image representation. Next, an insulating film is provided on each substrate so as to cover the common electrodes and the segment electrodes. The insulating film may be, for example, SiO formed by a sol-gel method₂-TiO₂The film of (1).

Next, liquid crystal alignment films are formed on the respective substrates, and one substrate is overlaid on the other substrate so that the liquid crystal alignment films face each other, and the periphery is bonded with a sealant. In the sealing agent, spacers may be generally mixed in order to control the substrate gap, and spacers for controlling the substrate gap are preferably scattered in the surface portion where the sealing agent is not provided. An opening portion into which liquid crystal can be filled from the outside is provided in a part of the sealant. Next, a liquid crystal material was injected into the space surrounded by the 2 substrates and the sealant through the opening provided in the sealant, and then the opening was sealed with an adhesive. The injection may be performed by a vacuum injection method or a method using a capillary phenomenon in the atmosphere. The liquid crystal material may be either a positive type liquid crystal material or a negative type liquid crystal material, and is preferably a negative type liquid crystal material. Subsequently, a polarizing plate was disposed. Specifically, a pair of polarizing plates was attached to the surfaces of the 2 substrates opposite to the liquid crystal layer.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. The abbreviations used below are as follows.

DA-1: 1, 5-bis (4-aminophenoxy) pentane

DA-2: 4, 4' -diaminodiphenylmethane

DA-3: 4, 4' -diaminodiphenylamine, CA-1: pyromellitic dianhydride

CA-2: 1,2,3, 4-cyclobutanetetracarboxylic dianhydride

CA-3: 3, 4-dicarboxy-1, 2,3, 4-tetrahydro-1-naphthalene succinic dianhydride

NMP: n-methyl-2-pyrrolidone, GBL: gamma butyrolactone,

BCS: butyl cellosolve, PB: 1-butoxy-2-propanol

DME: dipropylene glycol dimethyl ether

DPM: dipropylene glycol monomethyl ether

DAA: diacetone alcohol, DEDG: diethylene glycol diethyl ether

DIBC: 2, 6-dimethyl-4-heptanol

AD-1: a compound of the formula

< measurement of viscosity >

The viscosity of the polyamic acid, the liquid crystal aligning agent, and the like was measured at 25 ℃ using an E-type viscometer (manufactured by Toyobo industries Co., Ltd.).

< measurement of solid content concentration >

1.0g of the solution was weighed into an aluminum cup, and after heat treatment at 200 ℃ for 2 hours, the amount of solids remaining in the cup was measured to determine the solid content concentration of the solution.

[ production of Polyamic acid A1 ]

A2000 ml flask equipped with a nitrogen inlet tube and a stirrer was charged with DA-1171.8 g and 1676g of NMP, and dissolved by stirring while feeding nitrogen. While this diamine solution was stirred with water cooling, CA-1113.8 g was added, NMP was further added so that the solid content concentration became 12 wt%, and the mixture was stirred under nitrogen atmosphere at 50 ℃ for 20 hours to obtain a solution of polyamic acid (A1) (viscosity: 90 mPas). The polyamic acid (A1) solution was weighed out in an aluminum cup (1.0 g), and the solid content concentration in the treatment at 200 ℃ for 2 hours was 11.2% by weight.

[ production of polyamic acid solution a 1]

NMP 264.3g and BCS 200.0g were added to 535.7g of the polyamic acid (A1) solution to obtain a polyamic acid solution (a1) solution having a solid content concentration of 6.0 wt%.

[ production of polyamic acid solution a 2]

NMP 264.3g and PB 200.0g were added to 535.7g of the polyamic acid (A1) solution to obtain a polyamic acid solution (a2) solution having a solid content concentration of 6.0 wt%.

[ production of polyamic acid solution a 3]

NMP 264.3g and DME 200.0g were added to 535.7g of the polyamic acid (A1) solution to obtain a polyamic acid solution (a3) having a solid content concentration of 6.0 wt%.

[ production of Polyamic acid A2 ]

A2000 ml flask equipped with a nitrogen inlet pipe and a stirrer was charged with DA-1100.8 g and DA-534.9 g, and NMP 1337g was added thereto, and the mixture was dissolved by stirring while feeding nitrogen. While this diamine solution was stirred with water, CA-192.2 g was added, NMP was further added so that the solid content concentration became 12 wt%, and the mixture was stirred for 20 hours while being heated to 50 ℃ under a nitrogen atmosphere to obtain a solution of polyamic acid (A2) (viscosity: 520mmPa · s).

[ production of Polyamic acid B1 ]

A2000 ml four-necked flask equipped with a nitrogen inlet pipe and a stirrer was charged with DA-387.7 g, and 1052.5g of a solvent (hereinafter referred to as solvent 1) prepared by blending NMP and GBL at a ratio of 50% by weight was added thereto, and the mixture was dissolved with stirring while feeding nitrogen gas. While this diamine solution was stirred with water cooling, 270.1 g of CA-and 1382.7 g of a solvent were added, and the mixture was stirred with water cooling for 3 hours under a nitrogen atmosphere. Then, DA-221.8 g and 1191.3 g of solvent were added thereto and stirred. After DA-2 was dissolved, CA-333.0 g and 1287.0 g of a solvent were added thereto, and the mixture was stirred again under nitrogen atmosphere and water cooling for 3 hours to obtain a solution (viscosity: 65 mPas) of polyamic acid (B1) having a solid content of 9.8% by weight. The polyamic acid (B1) solution (1.0 g) was weighed out into an aluminum cup, and the solid content concentration when treated at 200 ℃ for 2 hours was 9.8% by weight.

[ production of Polyamic acid B2 ]

A2000 ml four-necked flask equipped with a nitrogen inlet pipe and a stirrer was charged with DA-395.6 g and DA-418.2 g, and 967g of NMP was added to dissolve them under stirring while feeding nitrogen. While this diamine solution was stirred with water cooling, CA-254.8 g and NMP 276g were added, and the mixture was stirred with water cooling for 3 hours under a nitrogen atmosphere. Then, CA-475.0 g and NMP were added so that the solid content concentration became 15 wt%, and the mixture was stirred at 50 ℃ for 12 hours under a nitrogen atmosphere to obtain a polyamic acid (B2) solution (viscosity: 302mmPa · s).

[ example 1]

153.4g of polyamic acid (B1) solution was weighed, and 1.3g of NMP, 38.5g of GBL solution containing 1.3 wt% of 3-glycidoxypropyltriethoxysilane, 95.9g of GBL, 53.5g of DME and 50.0g of DIBC were added to the solution, followed by stirring at room temperature for 1 hour. Then, aa3107.5g was added, and further stirred for 1 hour, thereby obtaining a solid component: NMP: GBL: DME: the ratio of DIBC was 4.3: 30: 40.7: 15: 10% (by weight) of solution (C1)500.0 g.

[ example 2]

153.4g of polyamic acid (B1) solution was weighed, and to the solution were added 1.3g of NMP and 38.5g of GBL solution containing 1.3 wt% of 3-glycidoxypropyltriethoxysilane, 120.9g of GBL, 28.5g of DME and 50.0g of DIBC, and the mixture was stirred at room temperature for 1 hour. Then, aa3107.5g was added, and further stirred for 1 hour, thereby obtaining a solid component: NMP: GBL: DME: DIBC 4.3: 30: 40.7: 10: 10% (by weight) of solution (C2)500.0 g.

[ example 3]

After stirring a mixture of 33.3g of a 12 wt% polyamic acid (a2) solution and 106.6g of a 15 wt% polyamic acid (B2) solution for 30 minutes, 11.1g of NMP, 20.0g of an NMP solution containing 1.0 wt% 3-glycidoxypropyltriethoxysilane, 204.0g of GBL, 75.0g of DME, and 50.0g of DIBC were added thereto, and the mixture was stirred at room temperature for 3 hours to obtain a polymer solid content ratio of a2 to B2 of 2: 8. solid content: NMP: GBL: DME: DIBC 4.2: 30: 40.8: 15: 10% (by weight) of solution (C8)500.0 g.

[ example 4]

After stirring a mixture of 33.3g of 12 wt% polyamic acid (A2) solution and 106.6g of 15 wt% polyamic acid (B2) solution for 30 minutes, 5.1g of NMP, 20.0g of NMP solution containing 1.0 wt% 3-glycidoxypropyltriethoxysilane, 6.0g of NMP solution containing 110 wt% AD, 204.0g of GBL, 75.0g of DME, and 50.0g of DIBC were added thereto, and the mixture was stirred at room temperature for 3 hours to obtain a solid content ratio of polymers A2 and B2 of 2: 8. solid content: NMP: GBL: DME: DIBC 4.2: 30: 40.8: 15: 10% (by weight) of solution (C9)500.0 g.

Comparative example 1

153.4g of polyamic acid (B1) solution was weighed, and 1.3g of NMP, 38.5g of GBL solution containing 1.3 wt% of 3-glycidoxypropyltriethoxysilane, 145.9g of GBL and 53.5g of DME were added to the solution, followed by stirring at room temperature for 1 hour. Then, aa3107.5g was added, and further stirred for 1 hour, thereby obtaining a solid component: NMP: GBL: DME 4.3: 30: 50.7: 15% (wt.)% of solution (C3)500.0 g.

Comparative example 2

153.4g of polyamic acid (B1) solution was weighed, and to the solution were added 1.3g of NMP, 38.5g of GBL solution containing 1.3 wt% of 3-glycidoxypropyltriethoxysilane, 145.9g of GBL and 53.5g of BCS, and the mixture was stirred at room temperature for 1 hour. Then, a1107.5g was added, and further stirred for 1 hour, thereby obtaining a solid component: NMP: GBL: BCS ═ 4.3: 30: 50.7: 15% (wt.)% of solution (C4)500.0 g.

Comparative example 3

153.4g of polyamic acid (B1) solution was weighed, and to the solution were added 1.3g of NMP, 38.5g of GBL solution containing 1.3 wt% of 3-glycidoxypropyltriethoxysilane, 95.9g of GBL, 53.5g of BCS and 50.0g of DPM, and the mixture was stirred at room temperature for 1 hour. Then, a1107.5g was added, and further stirred for 1 hour, thereby obtaining a solid component: NMP: GBL: BCS: DPM 4.3: 30: 40.7: 15: 10% (by weight) of solution (C5)500.0 g.

Comparative example 4

153.4g of polyamic acid (B1) solution was weighed, and to the solution were added 1.3g of NMP, 38.5g of GBL solution containing 1.3 wt% of 3-glycidoxypropyltriethoxysilane, 95.9g of GBL, 53.5g of DME and 50.0g of DPM, and the mixture was stirred at room temperature for 1 hour. Then, aa3107.5g was added, and further stirred for 1 hour, thereby obtaining a solid component: NMP: GBL: DME: DPM 4.3: 30: 40.7: 15: 10% (by weight) of solution (C6)500.0 g.

Comparative example 5

153.4g of polyamic acid (B1) solution was weighed, and to the solution were added 1.3g of NMP, 38.5g of GBL solution containing 1.3 wt% of 3-glycidoxypropyltriethoxysilane, 95.9g of GBL, 53.5g of PB and 50.0g of DPM, and the mixture was stirred at room temperature for 1 hour. Then, a 2107.5 g was added, and further stirred for 1 hour, thereby obtaining a solid content: NMP: GBL: PB: DPM 4.3: 30: 40.7: 15: 10% (by weight) of solution (C7)500.0 g.

The viscosity of each of examples 1 to 4 and comparative examples 1 to 5 was measured after filtration through a filter having a pore size of 1 μm, and is shown in Table 2. Then, the following coating property evaluation was performed.

[ evaluation of ink-jet coatability ]

Examples 1 to 4 and comparative examples 1 to 5 prepared as described above were coated on a TFT substrate using an inkjet coating apparatus (ishihyoki co., ltd). The coating was carried out under the conditions of a nozzle pitch of 127 μm, a coating speed of 250 mm/sec, a dispensing amount of 70pL and a coating area of 36X 36 mm. In addition, the coating was applied under the following conditions: after pre-drying at 110 ℃ for 1 minute on a hot plate, the film thickness was 120nm when the film was baked in an IR oven at 230 ℃ for 15 minutes.

[ evaluation method of coating film ]

The degree of dot or stripe unevenness due to the influence of contact holes or wirings was compared with the coating film obtained by pre-drying the coated substrate at 110 ℃, and evaluated by the following 4 grades.

When significant unevenness was visually observed over the entire surface, Lv4 was assumed, when unevenness was locally visually observed, Lv3 was assumed, when unevenness was not visually observed, Lv2 was assumed, and when no unevenness was observed under an optical microscope, Lv1 was assumed.

Further, the coating was also applied to a glass substrate whose surface was deposited with chromium, and the width of a portion where a color change (film thickness unevenness) existed at the end of the coating film was measured with a vernier caliper and evaluated as a Halo size. It is considered that the smaller the value of Halo size, the more excellent the coating film.

Further, the coating film width was actually measured, and the difference between the actually measured value and the set value was evaluated as dimensional stability for the set coating region. In this evaluation, the smaller the value, the more favorable the coating film was.

These results are shown in tables 1 and 2.

[ Table 1]

[ Table 2]

The entire contents of the specification, claims, drawings and abstract of japanese patent application 2016-072567 filed on 3/31 2016 are incorporated herein as disclosure of the present invention.

Claims

1. A liquid crystal aligning agent, comprising:

at least 1 polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide compound thereof; and the number of the first and second groups,

a solvent comprising the following solvent A, solvent B and solvent C,

solvent A: at least 1 selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, gamma-butyrolactone, and dimethylimidazolidinone,

solvent B: the dimethyl ether of dipropylene glycol,

solvent C: at least 1 selected from the group consisting of the following formulae a-22 and a-37,

wherein the liquid crystal aligning agent contains 10-60% by mass of solvent B and solvent C, and the solvent B is more than the solvent C.

2. The liquid crystal aligning agent according to claim 1, wherein the solvent A is N-methyl-2-pyrrolidone or γ -butyrolactone.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein the polyimide precursor has a structure represented by the following formula (1),

X₁being a tetravalent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a divalent organic radical derived from a diamine, R₁Is a hydrogen atom or an alkylene group of 1 to 5 carbon atoms, A₁And A₂Each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms.

4. The liquid crystal aligning agent according to claim 1 or 2, wherein the solvent A is contained in an amount of 20 to 80 mass% based on the total mass of the liquid crystal aligning agent.

5. The liquid crystal aligning agent according to claim 1 or 2, wherein the solvent B is contained in an amount of 1 to 30 mass% based on the total mass of the liquid crystal aligning agent.

6. The liquid crystal aligning agent according to claim 1 or 2, wherein the solvent C is contained in an amount of 1 to 30 mass% based on the total mass of the liquid crystal aligning agent.

7. The liquid crystal aligning agent according to claim 1 or 2, wherein the solvent A is contained in an amount of 50 to 80 mass%, the solvent B is contained in an amount of 1 to 30 mass%, and the solvent C is contained in an amount of 1 to 20 mass%, based on the total mass of the liquid crystal aligning agent.

8. The liquid crystal aligning agent according to claim 1 or 2, wherein the solvent B is contained in an amount of 1 to 20 mass% more than the solvent C.

9. The liquid crystal aligning agent according to claim 1 or 2, which is used for film formation by an inkjet method.

10. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 9.

11. A liquid crystal display element comprising the liquid crystal alignment film according to claim 10.