TWI852461B - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal element - Google Patents

Abstract

The present invention provides a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal element which are not easy to make a printing plate swell and have good printing properties. The liquid crystal alignment agent of the present invention contains a polymer component and a specific solvent which is tetrahydro-4H-pyran-4-one.

Description

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

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal element.

In the past, liquid crystal elements have developed various driving methods with different electrode structures or physical properties of the liquid crystal molecules used, such as twisted nematic (TN) type or super twisted nematic (STN) type, vertical alignment (VA) type, in-plane switching type (IPS (In-Plane Switching) type), fringe field switching (FFS) type, optical compensation bending type (OCB (Optical Compensated Bend) type) and other liquid crystal elements. These liquid crystal elements have a liquid crystal alignment film for aligning the liquid crystal molecules. In terms of various excellent properties such as heat resistance, mechanical strength, and affinity with liquid crystals, the material of the liquid crystal alignment film uses polyamide or polyimide.

Regarding the liquid crystal alignment agent, a polymer component is dissolved in a solvent, and the liquid crystal alignment agent is applied to a substrate and heated to form a liquid crystal alignment film. Here, the solvent of the liquid crystal alignment agent generally uses an organic solvent with high solubility of the polymer, such as a non-protonic polar solvent such as N-methyl-2-pyrrolidone or γ-butyrolactone. In addition, in order to make the liquid crystal alignment agent have good coating properties (printing properties) when the liquid crystal alignment agent is applied to the substrate, an aprotic polar solvent and an organic solvent with relatively low surface tension such as butyl solvent are used (for example, refer to Patent Document 1 or Patent Document 2).

As a method for applying a liquid crystal alignment agent to a substrate, various methods such as spin coating, offset printing, and inkjet are applied. For example, the offset printing method is usually performed using the following transfer printing device, which applies the liquid crystal alignment agent to a printing plate containing a resin such as APR (registered trademark), and uses the printing plate to transfer the liquid crystal alignment agent to the substrate (for example, refer to Patent Document 3). [Prior Art Document]

[Patent Documents] [Patent Document 1] Japanese Patent Publication No. 2010-97188 [Patent Document 2] Japanese Patent Publication No. 2010-156934 [Patent Document 3] Japanese Patent Publication No. 2001-343649

[The problem the invention is trying to solve]

Butyl solvents, which are commonly used to improve the coating properties of liquid crystal alignment agents, tend to swell APR resins. Therefore, when a liquid crystal alignment agent containing butyl solvent is coated on a substrate by offset printing, there is a concern that the printing plate swells due to repeated coating and the printing properties are reduced. In addition, as a solvent component of a liquid crystal alignment agent, it is required that the polymer is not easily precipitated onto the printing machine even when printing is performed continuously, so that the printing properties (continuous printing properties) are good.

The present invention is made in view of the above-mentioned subject, and one of the purposes is to provide a liquid crystal alignment agent that is not easy to cause the printing plate to swell and has good printing properties. [Means for solving the problem]

The inventors of the present invention have actively studied to achieve the above-mentioned problems of the prior art, and found that the above-mentioned problems can be solved by using a specific organic solvent as a solvent, thereby completing the present invention. Specifically, the present invention provides the following liquid crystal alignment agent, liquid crystal alignment film and liquid crystal element.

One aspect of the present invention is to provide a liquid crystal alignment agent, which contains a polymer component and a specific solvent of tetrahydro-4H-pyran-4-one.

By using the specific solvent as a solvent component of the liquid crystal alignment agent, a liquid crystal alignment agent whose printing plate is not easily swollen can be obtained. In addition, even when printing is performed continuously, the polymer is not easily precipitated on the printing machine, and the printing property can be improved.

Another aspect of the present invention is to provide a liquid crystal alignment film formed by the liquid crystal alignment agent. In addition, another aspect is to provide a liquid crystal element having a liquid crystal alignment film formed by the liquid crystal alignment agent.

The liquid crystal alignment film of the present invention is formed by using a liquid crystal alignment agent containing the specific solvent, so that a uniform coating film with good film quality can be formed. In addition, when the liquid crystal alignment agent is used to manufacture a liquid crystal element, printing defects can be reduced in the manufacturing process, and as a result, the yield of the product can be improved.

Hereinafter, each component contained in the liquid crystal alignment agent of the present invention and other components arbitrarily prepared as needed will be described.

<Polymer component> The liquid crystal alignment agent of the present invention contains a polymer component. The main skeleton of the polymer is not particularly limited, and examples thereof include: polyamic acid, polyamic acid ester, polyimide, polysiloxane, polyester, polyamide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, polystyrene derivative, poly(styrene-phenylenediamide) derivative, poly(meth)acrylate and the like. In addition, (meth)acrylate refers to acrylate and methacrylate.

In terms of the high improvement effect of the specific solvent on printability, the polymer component of the liquid crystal alignment agent is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polysiloxane. In addition, when preparing the liquid crystal alignment agent, the polymer can be used alone or in combination of two or more.

[Polyamide] The polyamide in the present invention can be obtained, for example, by reacting tetracarboxylic dianhydride with diamine.

(Tetracarboxylic dianhydride) Examples of tetracarboxylic dianhydride used for the synthesis of polyamide include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, etc. Specific examples of these tetracarboxylic dianhydrides include aliphatic tetracarboxylic dianhydride, such as 1,2,3,4-butanetetracarboxylic dianhydride, etc. Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxy-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxy-3-furanyl)-naphtho[1,2-c ]furan-1,3-dione, 3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic 2:4,6:8-dianhydride, 4,9-dioxabicyclo[5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, cyclohexane tetracarboxylic dianhydride, etc.; Aromatic tetracarboxylic dianhydride, for example, pyromellitic dianhydride, etc.; In addition, tetracarboxylic dianhydride described in Japanese Patent Laid-Open No. 2010-97188 can also be used. In addition, tetracarboxylic dianhydride can be used alone or in combination of two or more.

In terms of improving electrical properties, further improving the solubility of the polymer in a solvent containing a specific solvent, and further improving the effect of improving printability, the tetracarboxylic dianhydride used in the synthesis preferably includes alicyclic tetracarboxylic dianhydride. In addition, among the alicyclic tetracarboxylic dianhydrides, it is preferred to include a tetracarboxylic dianhydride selected from 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxy-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxy-3-furanyl)-naphtho[1,2-c]furan-1,3- The present invention preferably comprises at least one selected from the group consisting of diketones, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid 2:4,6:8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, and particularly preferably comprises at least one selected from the group consisting of 2,3,5-tricarboxycyclopentylacetic acid dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid 2:4,6:8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride.

When the tetracarboxylic dianhydride comprises at least one selected from the group consisting of 2,3,5-tricarboxycyclopentylacetic dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic dianhydride 2:4,6:8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride, the total content of these compounds is preferably 10 mol % or more, more preferably 20 mol % to 100 mol % relative to the total amount of tetracarboxylic dianhydride used in the synthesis of polyamide.

(Diamine) Examples of diamines used in the synthesis of polyamide include aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, etc. Specific examples of these diamines include aliphatic diamines such as m-xylylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, etc.; examples of alicyclic diamines include 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc.;

Examples of aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 1,3-bis(4-aminophenoxy)propane, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoro Propane, 4,4'-(p-phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 2,6-diaminopyridine, 3,6-diaminooxazole, N,N'-bis(4-aminophenyl)-benzidine, 1,4-bis-(4-aminophenyl)-piperazine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H- Indene-6-amine, 3,5-diaminobenzoic acid, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanosteryl 3,5-diaminobenzoate, 3,6-bis(4-aminobenzyloxy)cholestane, 4-(4'-trifluoromethoxybenzyloxy)cyclohexyl-3,5-diaminobenzene formate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-(4-heptylcyclohexyl)cyclohexane, 2,4-diamino-N,N-diallylaniline, 4-aminobenzylamine, N-[4-(2-aminoethyl)phenyl]benzene-1,4-diamine, N-[4-(aminomethyl)phenyl]benzene-1,4-diamine, a diamine containing a cinnamic acid structure, and the following formula (D-1): [Chemical 2] (In formula (D-1), X ^I and X ^II are independently a single bond, -O-, *-COO-, *-OCO- or *-NH-CO- (wherein the bond with "*" is bonded to the diaminophenyl group), R ^I and R ^II are independently an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, b is an integer from 0 to 2, c is an integer from 1 to 20, n is 0 or 1, and m is 0 or 1; wherein a and b are not both 0, and when X ^I is *-NH-CO-, n is 0) compounds represented by the following; examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, etc.; in addition, diamines described in Japanese Patent Laid-Open No. 2010-97188 can also be used. Furthermore, these diamines may be used alone or in combination of two or more.

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

The diamine used for synthesizing polyamide preferably contains 30 mol% or more of the aromatic diamine based on all diamines, more preferably 50 mol% or more, and particularly preferably 80 mol% or more.

(Synthesis of polyamide) Polyamide can be obtained by reacting the above-mentioned tetracarboxylic dianhydride and diamine together with a molecular weight regulator as needed. The ratio of tetracarboxylic dianhydride and diamine used in the synthesis reaction of polyamide is preferably 0.2 to 2 equivalents of the anhydride group of tetracarboxylic dianhydride to 1 equivalent of the amino group of diamine. Examples of molecular weight regulators include: monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The molecular weight regulator is preferably used in a ratio of 20 parts by weight or less relative to a total of 100 parts by weight of the tetracarboxylic dianhydride and diamine used.

The synthesis reaction of polyamine is preferably carried out in an organic solvent. The reaction temperature is preferably -20℃～150℃, and the reaction time is preferably 0.1 hour～24 hours. The organic solvent used in the reaction can be listed as follows: aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc. The particularly preferred organic solvent is preferably one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphatamide, m-cresol, xylenol, halogenated phenol and the specific solvents shown below, or a mixture of one or more of these solvents and other organic solvents (such as butyl solvent, diethylene glycol diethyl ether, etc.). The amount of the organic solvent used (a) is preferably set to an amount of 0.1% by weight to 50% by weight of the total amount of tetracarboxylic dianhydride and diamine (b) relative to the total amount of the reaction solution (a+b). The reaction solution in which the polyamide acid is dissolved is obtained in the manner described above. The reaction solution can be directly provided for the preparation of the liquid crystal alignment agent, or the polyamine contained in the reaction solution can be separated and then provided for the preparation of the liquid crystal alignment agent.

[Polyimide] The polyimide of the present invention can be obtained, for example, by subjecting the polyimide synthesized in the above manner to dehydration and ring closure to imidization. The polyimide may be a completely imidized product in which the amide structure of the polyimide serving as its precursor is completely dehydrated and ring closed, or a partially imidized product in which only a part of the amide structure is dehydrated and ring closed so that the amide structure and the imide ring structure coexist. The imidization rate of the polyimide of the present invention is preferably 30% or more, more preferably 40% to 99%, and even more preferably 50% to 99%. The imidization rate is the ratio of the number of imide ring structures to the total number of imide structures and imide ring structures of the polyimide, expressed as a percentage. Here, a part of the imide ring may also be an isoimide ring.

The dehydration and ring closure of polyamine is preferably carried out by the following methods: a method of heating polyamine; or a method of dissolving polyamine in an organic solvent, adding a dehydrating agent and a dehydration and ring closure catalyst to the solution and heating as needed. The latter method is preferred. In the method of adding a dehydrating agent and a dehydration and ring closure catalyst to the solution of polyamine, anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent used is preferably set to 0.01 mol to 20 mol relative to 1 mol of the amide structure of the polyamine. The dehydration ring-closing catalyst may be, for example, a tertiary amine such as pyridine, colloidal pyridine, dimethylpyridine, or triethylamine. The amount of the dehydration ring-closing catalyst used is preferably 0.01 mol to 10 mol relative to 1 mol of the dehydrating agent used. The organic solvent used for the dehydration ring-closing reaction may be the organic solvent exemplified as the organic solvent used for the synthesis of polyamide. The reaction temperature of the dehydration ring-closing reaction is preferably 0°C to 180°C, and the reaction time is preferably 1.0 hour to 120 hours.

A reaction solution containing polyimide is obtained in the above manner. The reaction solution can be directly provided for the preparation of a liquid crystal alignment agent, or provided for the preparation of a liquid crystal alignment agent after removing a dehydrating agent and a dehydration ring-closing catalyst from the reaction solution, or provided for the preparation of a liquid crystal alignment agent after separating the polyimide. These purification operations can be performed according to known methods. In addition, polyimide can also be obtained by imidization of polyamic acid esters.

[Polyamide] The polyamide in the present invention can be obtained, for example, by the following methods: [I] a method of reacting the polyamide obtained by the above-mentioned synthesis reaction with an esterifying agent (e.g., methanol or ethanol, N,N-dimethylformamide diethyl acetal, etc.); [II] a method of reacting a tetracarboxylic acid diester with a diamine in an organic solvent in the presence of a suitable dehydration catalyst (e.g., 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholinium halide, a phosphorus-based condensation agent, etc.); [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine in an organic solvent in the presence of a suitable base (e.g., pyridine, triethylamine, sodium hydroxide, etc.), etc. The polyamic acid ester contained in the liquid crystal alignment agent may have only an aminate structure, or may be a partially esterified product in which an aminate structure and an aminate structure coexist. In addition, the reaction solution obtained by dissolving the polyamic acid ester may be directly provided for the preparation of the liquid crystal alignment agent, or the polyamic acid ester contained in the reaction solution may be separated and then provided for the preparation of the liquid crystal alignment agent.

The polyamine, polyamine ester and polyimide obtained in the above manner preferably have a solution viscosity of 10 mPa·s to 800 mPa·s when prepared into a solution with a concentration of 10 wt %, and more preferably have a solution viscosity of 15 mPa·s to 500 mPa·s. In addition, the solution viscosity (mPa·s) of the polymer is a value obtained by measuring a 10 wt % polymer solution prepared using a good solvent of the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) at 25°C using an E-type rotational viscometer. Regarding the polyamine, polyamine ester and polyimide contained in the liquid crystal alignment agent of the present invention, the weight average molecular weight of polystyrene conversion measured by gel permeation chromatography (GPC) is preferably 500 to 100,000, and more preferably 1,000 to 50,000.

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

Examples of the hydrolyzable silane compounds used in the synthesis of polyorganosiloxane include alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, trimethoxysilylpropylsuccinic anhydride, dimethyldimethoxysilane, and dimethyldiethoxysilane; 3-butylpropyltrimethoxysilane, 3-butylpropyltriethoxysilane, butylmethyltrimethoxysilane, butylmethyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(3-cyclohexylamino)propyltrimethoxysilane, and the like. Silane and other nitrogen and sulfur-containing alkoxysilane compounds; silane compounds containing epoxy groups such as 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; alkoxysilane compounds containing unsaturated bonds such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, and p-phenylenetrimethoxysilane. The hydrolyzable silane compound may be used alone or in combination of two or more of these silane compounds. In addition, the term "(meth)acryloxy group" means including "acryloxy group" and "methacryloxy group".

The hydrolysis-condensation reaction is carried out by reacting one or more of the above-mentioned silane compounds with water, preferably in the presence of a suitable catalyst and an organic solvent. During the reaction, the water is preferably used in an amount of 1 to 30 mol relative to 1 mol of the silane compound (total amount). Examples of the catalyst used include: acids, alkaline metal compounds, organic bases (such as triethylamine or tetramethylammonium hydroxide), titanium compounds, zirconium compounds, etc. The amount of the catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, etc., and should be appropriately set. For example, it is preferably 0.01 to 3 times the total amount of the silane compound. The organic solvent used may be, for example, hydrocarbons, ketones, esters, ethers, alcohols, etc. Among these organic solvents, it is preferred to use water-insoluble or water-slightly soluble organic solvents. The preferred usage ratio of the organic solvent is 50 to 1,000 parts by weight relative to 100 parts by weight of the total silane compound used in the reaction.

The hydrolysis-condensation reaction is preferably carried out by heating in an oil bath, for example. In this case, the heating temperature is preferably set to 130° C. or less, and the heating time is preferably set to 0.5 to 12 hours. After the reaction is completed, the polyorganosiloxane can be obtained by removing the solvent from the organic solvent layer separated from the reaction solution.

When used as a liquid crystal alignment agent for TN-type, STN-type or vertical alignment liquid crystal display elements, specific groups such as liquid crystal alignment groups or groups having photoalignment structures can be introduced into the side chains of polyorganosiloxane. The method for synthesizing polyorganosiloxane having these specific groups on the side chains is not particularly limited, and for example, the following methods can be cited: a method of synthesizing polyorganosiloxane having epoxy groups by hydrolyzing and condensing an epoxy-containing silane compound or a mixture of an epoxy-containing silane compound and other silane compounds, and then reacting the obtained epoxy-containing polyorganosiloxane with a carboxylic acid having the specific groups. The reaction of the epoxy-containing polyorganosiloxane with the carboxylic acid can be carried out according to a known method.

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

In the liquid crystal alignment agent of the present invention, the content ratio of the polymer selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane relative to the total amount of the polymer components in the liquid crystal alignment agent (the total amount when two or more types are contained) is preferably 50% by weight or more, and more preferably 60% by weight or more. In addition, from the viewpoint of better obtaining the effect of the present invention, the polymer component preferably includes at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide. The total content ratio of polyamic acid, polyamic acid ester and polyimide in the liquid crystal alignment agent is preferably 40 wt % or more, more preferably 60 wt % or more, relative to the total amount of polymer components in the liquid crystal alignment agent.

<Solvent> The liquid crystal alignment agent of the present invention is a liquid composition obtained by dispersing or dissolving a polymer component in a solvent. The liquid crystal alignment agent contains at least one specific solvent selected from the group consisting of a solvent having a phosphorus atom (hereinafter also referred to as a "phosphorus-containing solvent"), N,N-dimethylpropylurea, tetrahydro-4H-pyran-4-one, tetramethylene sulfone, 3-methylcyclohexanone, 4-methylcyclohexanone, a compound represented by the formula (1), a compound represented by the formula (2), a compound represented by the formula (3), and a compound represented by the formula (10).

[Phosphorus-containing solvent] The phosphorus-containing solvent is not particularly limited as long as it is a compound having at least one phosphorus atom in the molecule, but is preferably at least one selected from the group consisting of compounds represented by the following formulae (P-1) to (P-4). [Chemical 4] (In formula (p-1) to formula (p-4), ^X1 and ^Y1 are independently an oxygen atom or a sulfur atom; ^R1 is a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms, and ^R2 is a hydrogen atom or a monovalent organic group; wherein ^R1 and ^R2 may be bonded to each other to form a ring; ^R3 are independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and the two ^R3 bonded to the nitrogen atom may be bonded to each other to form a monovalent nitrogen-containing heterocyclic group together with the nitrogen atom; wherein ^R1 and ^R2 are not hydrogen atoms at the same time, and ^R2 and ^R3 are not hydrogen atoms at the same time; m, n, k and j are independently integers of 1 to 3; when m, n, k and j are 2 or 3, the multiple ^R1 , R2 in the formula ³ may be the same or different from each other, and when m, n, k, and j are 1, multiple R ² in the formula may be the same or different from each other)

Here, in this specification, the so-called "alkyl group" includes chain alkyl groups, alicyclic alkyl groups and aromatic alkyl groups. The so-called "chain alkyl group" refers to a straight chain alkyl group and a branched alkyl group that does not contain a ring structure on the main chain but is composed only of a chain structure. Among them, it can be saturated or unsaturated. The so-called "alicyclic alkyl group" refers to a alkyl group that contains only the structure of alicyclic hydrocarbons as a ring structure and does not contain an aromatic ring structure. Among them, it is not necessary to be composed only of the structure of alicyclic hydrocarbons, and it also includes alkyl groups with a chain structure in part. The so-called "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessarily composed of only an aromatic ring structure, and a chain structure or an alicyclic hydrocarbon structure may be contained in part thereof. In addition, in this specification, the so-called "organic group" refers to a group containing carbon atoms, and may also contain heteroatoms in the structure.

In the formula (p-1), the monovalent alkyl group having 1 to 10 carbon atoms represented by ^R1 may be, for example, a linear or branched alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, etc.; an alkenyl group such as vinyl, allyl, etc.; an alkynyl group such as ethynyl, etc.; a cycloalkyl group such as cyclopentyl, cyclohexyl, methylcyclohexyl, etc.; an aryl group such as phenyl, tolyl, xylyl, etc.; an aralkyl group such as benzyl, phenethyl, styryl, etc. Among the above groups, ^R1 is preferably an alkyl group having 1 to 3 carbon atoms.

Examples of the monovalent organic group of ^R2 include a monovalent alkyl group having 1 to 10 carbon atoms, a group containing a heteroatom between the carbon-carbon bonds of the alkyl group, a group in which the alkyl group and the heteroatom-containing group are bonded, a group in which at least one hydrogen atom of these groups is substituted with a substituent, a cyano group, a formyl group, etc. Here, the heteroatom-containing group refers to a divalent or higher valent group having a heteroatom, and examples thereof include -O-, -CO-, -COO-, -CONR ^a - (R ^a is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, the same below), -NR ^a -, a trivalent nitrogen atom, -NR ^a CONR ^a -, -OCONR ^a -, -S-, -COS-, -OCOO-, -SO ₂ -, etc. Examples of the substituent include halogen atoms, nitro groups, cyano groups, hydroxyl groups, etc. Among the above groups, ^R2 is preferably an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 or 7 carbon atoms.

The alkyl group with 1 to 6 carbon atoms of R ³ may be straight chain or branched. The monovalent nitrogen-containing heterocyclic group formed by two R ^3s bonding to each other may be a group formed by removing the hydrogen atom bonded to the nitrogen atom possessed by the nitrogen-containing heterocyclic group. Specific examples of the nitrogen-containing heterocyclic group include pyridine ring, piperidine ring, etc., and these rings may also have substituents such as halogen atoms and alkyl groups. R ³ is preferably an alkyl group with 1 to 3 carbon atoms, and more preferably a methyl group. X ¹ and Y ¹ are preferably oxygen atoms. m, n, k and j are preferably 2 or 3, and more preferably 3.

In terms of achieving a higher improvement in printability, among the formulas (p-1) to (p-4), the phosphorus-containing solvent is preferably at least one selected from the group consisting of the compound represented by the formula (p-1) and the compound represented by the formula (p-3), and more preferably the compound represented by the formula (p-1).

Preferred specific examples of the phosphorus-containing solvent include compounds represented by the following formulae (p-1-1) to (p-1-7), (p-3-1) and (p-3-2). [Chemistry 5]

Among the above compounds, the phosphorus-containing solvent is particularly preferably a compound represented by each of the above formula (p-1-1) to (p-1-4) and (p-3-1) from the viewpoint of better printability. The phosphorus-containing solvent may be used alone or in combination of two or more.

[Compounds represented by the formula (1)] In the formula (1), the alkyl group having 1 to 6 carbon atoms represented by ^R4 may be, for example, methyl, ethyl, propyl, butyl, etc., and these alkyl groups may be linear or branched. Specific examples of the compound represented by the formula (1) include 4-formylmorpholine, 4-acetylmorpholine, etc., among which 4-formylmorpholine is particularly preferred. In addition, the compound represented by the formula (1) may be used alone or in combination of two or more.

[Compounds represented by the formula (2)] In the formula (2), the examples of alkyl groups having 1 to 6 carbon atoms represented by ^R5 are the same as those described for ^R4 in the formula (1). Examples of alkanediyl groups having 2 to 4 carbon atoms represented by ^R6 include ethyl, propylene, and butanediyl, and these alkanediyl groups may be linear or branched. Specific examples of the compounds represented by the formula (2) include 3-methyl-2-oxazolidinone, 3-ethyl-2-oxazolidinone, 3-isopropyl-2-oxazolidinone, and N-methyl-2-oxazinanone, among which 3-methyl-2-oxazolidinone is particularly preferred. In addition, the compounds represented by the formula (2) may be used alone or in combination of two or more.

[Compounds represented by the formula (3)] In the formula (3), the monovalent organic groups of ^R7 to ^R10 include, for example, an alkyl group having 1 to 10 carbon atoms, a group containing a heteroatom between the carbon-carbon bonds of the alkyl group, a group in which the alkyl group and the heteroatom-containing group are bonded, and a group in which at least one hydrogen atom of these groups is substituted by a substituent. Regarding specific examples of the heteroatom-containing group and the substituent, the description of ^R2 in the formula (p-1) can be applied. In addition, ^R7 to ^R10 may be the same as or different from each other. ^R7 to ^R10 are preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or ^-CORb ( ^Rb is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms). One of ^R7 and ^R10 is preferably ^-CORb .

Specific examples of the compound represented by the formula (3) include 2-furaldehyde, 3-furaldehyde, 5-methyl-2-furaldehyde, 5-methyl-3-furaldehyde, 4-methyl-2-furaldehyde, 5-hydroxymethyl-2-furaldehyde, etc., among which 5-methyl-2-furaldehyde is particularly preferred. In addition, the compound represented by the formula (3) can be used alone or in combination of two or more.

[Compounds represented by the formula (10)] In the formula (10), examples of the alkyl group having 1 to 3 carbon atoms represented by R ¹¹ to R ¹³ include methyl, ethyl, n-propyl, and isopropyl, and methyl is preferred. Specific examples of the compound represented by the formula (10) include lactamide, N,N-dimethyl lactamide, N,N-diethyl lactamide, N-methyl-N-propyl lactamide, N-ethyl lactamide, and N-isopropyl lactamide, and N,N-dimethyl lactamide is particularly preferred. The compound represented by the formula (10) may be used alone or in combination of two or more.

In terms of better printability (particularly continuous printability), among the above compounds, at least one selected from the group consisting of phosphorus-containing solvents, N,N-dimethylpropylurea, compounds represented by the above formula (1) and compounds represented by the above formula (2) is preferred as the specific solvent. The specific solvent may be used alone or in combination of two or more.

[Other solvents] The liquid crystal alignment agent of the present invention may also contain solvents other than the specific solvents (hereinafter, also referred to as "other solvents"). Specific examples of other solvents include: N-ethyl-2-pyrrolidone, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl -2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, 3-butoxy-N,N-dimethylpropaneamide, 3-methoxy-N,N-dimethylpropaneamide, 3-hexyloxy-N,N-dimethylpropaneamide, isopropoxy-N-isopropyl-propionamide, n-butoxy-N-isopropyl-propionamide, 1,3-dimethyl-2-imidazolidinone 、N,N'-dimethylpropylurea, tetramethylurea, N-methyl-2-pyrrolidone, γ-butyrolactone, δ-valerolactone, γ-valerolactone, γ-caprolactone, N,N-diethylacetamide, γ-butyrolactamide, N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethylene glycol-n-butyl ether (butyl solvent), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether (dipropylene glycol monomethyl ether (DPM), diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, ethyl carbonate, propyl carbonate, etc. In addition, other solvents can be used alone or in combination of two or more compounds.

Regarding the specific solvent, all the solvents contained in the liquid crystal alignment agent may be set as the specific solvent, or a part of the solvents may be set as the specific solvent. The content ratio of the specific solvent relative to the total volume of the solvents contained in the liquid crystal alignment agent (the total amount when two or more solvents are used, the same below) is preferably 1 wt% to 80 wt%, more preferably 5 wt% to 70 wt%, further preferably 10 wt% to 60 wt%, and particularly preferably 20 wt% to 60 wt%.

<Other components> The liquid crystal alignment agent of the present invention contains the polymer component and solvent as described above, and may contain other components as needed. The other components include, for example: compounds having at least one epoxy group in the molecule, functional silane compounds, photopolymerizable compounds, surfactants, fillers, defoamers, sensitizers, dispersants, antioxidants, adhesion aids, antistatic agents, leveling agents, antibacterial agents, etc. The mixing ratio of these components can be appropriately set according to the compounds to be mixed within the range that does not hinder the effect of the present invention.

The solid component concentration in the liquid crystal alignment agent of the present invention (the ratio of the total weight of the components other than the solvent of the liquid crystal alignment agent to the total weight of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., and is preferably in the range of 1 wt % to 10 wt %. That is, the liquid crystal alignment agent of the present invention is coated on the surface of the substrate in the manner described below, and preferably heated to form a coating film as a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. However, at this time, when the solid component concentration is less than 1 wt %, the film thickness of the coating becomes too small and it becomes difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10 wt %, the film thickness of the coating becomes too large to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases, which tends to reduce coating properties.

The range of particularly preferred solid component concentration varies depending on the method used when applying the liquid crystal alignment agent to the substrate. For example, in the case of a spin coating method, a solid component concentration in the range of 1.5 wt% to 4.5 wt% is particularly preferred. In the case of an offset printing method, it is particularly preferred to set the solid component concentration in the range of 3 wt% to 9 wt%, and thereby set the solution viscosity in the range of 12 mPa·s to 50 mPa·s. In the case of an inkjet method, it is particularly preferred to set the solid component concentration in the range of 1 wt% to 5 wt%, and thereby set the solution viscosity in the range of 3 mPa·s to 15 mPa·s. The temperature when preparing the liquid crystal alignment agent is preferably 10°C to 50°C, and more preferably 20°C to 30°C.

<Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present invention is formed by a liquid crystal alignment agent prepared in the above manner. In addition, the liquid crystal element of the present invention has a liquid crystal alignment film formed using the liquid crystal alignment agent. The driving mode of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied to a variety of driving modes such as TN type, STN type, IPS type, FFS type, VA type, multi-domain vertical alignment (Multi-domain Vertical Alignment, MVA) type, polymer sustained alignment (Polymer sustained alignment, PSA) type, etc. The liquid crystal element of the present invention can be manufactured, for example, using a method including the following steps 1 to 3. Regarding step 1, the substrate used is different depending on the desired driving mode. Steps 2 and 3 are common to each driving mode.

[Step 1: Formation of coating film] First, the liquid crystal alignment agent of the present invention is coated on a substrate, and then the coated surface is heated to form a coating film on the substrate. (1-1) In the case of manufacturing a TN type, STN type, VA type, MVA type or PSA type liquid crystal element, two substrates provided with patterned transparent conductive films are set as a pair, and the liquid crystal alignment agent is coated on the transparent conductive film formation surface of each substrate by preferably offset printing, spin coating, roll coating or inkjet printing. The substrate may be made of glass such as float glass or sodium glass, or a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, or poly(aliphatic cycloolefin). The transparent conductive film provided on one surface of the substrate may be a NESA film (registered trademark of PPG, USA) containing tin oxide (SnO ₂ ), an indium tin oxide (ITO) film containing indium oxide-tin oxide (IN ₂ O ₃ -SnO ₂ ), or the like.

After applying the liquid crystal alignment agent, it is preferred to perform preliminary heating (pre-baking) for the purpose of preventing the applied alignment agent from dripping. The preferred pre-baking temperature is 30°C to 200°C, and the preferred pre-baking time is 0.25 minutes to 10 minutes. Thereafter, a calcination (post-baking) step is performed for the purpose of completely removing the solvent and, if necessary, thermally imidizing the amide structure present in the polymer. The preferred calcination temperature (post-baking temperature) at this time is 80°C to 300°C, and the preferred post-baking time is 5 minutes to 200 minutes. The thickness of the film formed in the above manner is preferably 0.001 μm to 1 μm, more preferably 0.005 μm to 0.5 μm.

(1-2) When manufacturing an IPS or FFS type liquid crystal display element, a liquid crystal alignment agent is applied to the electrode-forming surface of a substrate having an electrode including a comb-shaped patterned transparent conductive film or metal film, and to one of the surfaces of an opposing substrate having no electrode, and then each coated surface is heated to form a coating film. The materials of the substrate and transparent conductive film used at this time, the coating method, the heating conditions after coating, the film thickness, etc. are the same as those in (1-1). The metal film may be a film containing a metal such as chromium, for example. In either case (1-1) or (1-2), a liquid crystal alignment film or a coating that becomes a liquid crystal alignment film is formed by coating a liquid crystal alignment agent on a substrate and then removing the organic solvent.

[Step 2: Alignment ability imparting treatment] In the case of manufacturing TN type, STN type, IPS type or FFS type liquid crystal display elements, a treatment of imparting liquid crystal alignment ability to the coating film formed in the step 1 is performed. As a result, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. The alignment ability imparting treatment can be listed as follows: a friction treatment of wiping the coating film in a certain direction using a roller wrapped with a cloth containing fibers such as nylon, rayon, cotton, etc., a light alignment treatment of irradiating the coating film with polarized or non-polarized radiation, etc. On the other hand, in the case of manufacturing a VA type liquid crystal display element, the coating film formed in the step 1 can be used directly as a liquid crystal alignment film, or the film can be subjected to an alignment ability imparting treatment. The liquid crystal alignment film that is better for VA type liquid crystal display elements can also be better used for PSA (Polymer sustained alignment) type liquid crystal display elements.

[Step 3: Construction of liquid crystal cell] Prepare two substrates with liquid crystal alignment films formed in the above manner, and arrange liquid crystal between the two opposing substrates to manufacture a liquid crystal cell. For example, the following methods can be used to manufacture a liquid crystal cell: (1) Arrange two substrates opposite to each other with a gap between them so that the liquid crystal alignment films face each other, and use a sealant to bond the peripheries of the two substrates together, inject liquid crystal into the cell gap divided by the substrate surface and the sealant, and then seal the injection hole; (2) Apply a sealant to a predetermined position on one of the substrates with a liquid crystal alignment film formed, and then drip liquid crystal at a predetermined number of locations on the surface of the liquid crystal alignment film, and then bond the other substrate so that the liquid crystal alignment films face each other, and spread the liquid crystal over the entire surface of the substrate (liquid crystal dripping (One Drop Fill, ODF) method), etc. It is ideal to further heat the manufactured liquid crystal unit to a temperature at which the liquid crystal used acquires an isotropic phase, and then slowly cool it to room temperature, thereby removing the flow alignment during liquid crystal filling.

The sealant may be, for example, an epoxy resin containing a hardener and aluminum oxide balls as spacers. Examples of liquid crystals include nematic liquid crystals and discotic liquid crystals, of which nematic liquid crystals are preferred, and examples thereof include: Schiff base liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, dicyclooctane liquid crystals, cubane liquid crystals, etc. In addition, cholesterol liquid crystals, chiral agents, ferroelectric liquid crystals, etc. may be added to these liquid crystals for use.

In the case of manufacturing a PSA type liquid crystal display element, a liquid crystal cell is constructed in the same manner as described above except that a photopolymerizable compound is injected or dripped together with the liquid crystal. Thereafter, the liquid crystal cell is irradiated with light while a DC or AC voltage is applied between the conductive films of a pair of substrates. In addition, in the case of forming a coating film on a substrate using a liquid crystal alignment agent containing a photopolymerizable compound, a liquid crystal cell is constructed in the same manner as described above, and thereafter, a liquid crystal element is manufactured by irradiating the liquid crystal cell with light while a DC or AC voltage is applied between the conductive films of a pair of substrates.

Furthermore, the liquid crystal display element of the present invention can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell. The polarizing plate attached to the outer surface of the liquid crystal cell can be exemplified by a polarizing plate formed by sandwiching a polarizing film called "H film" with a cellulose acetate protective film or a polarizing plate containing the H film itself, wherein the "H film" is formed by extending and aligning polyvinyl alcohol while absorbing iodine.

The liquid crystal element of the present invention can be effectively applied to a variety of devices, such as clocks, portable game consoles, word processors, notebook personal computers, car navigation systems, video recorders, personal digital assistants (PDAs), digital cameras, mobile phones, smart phones, various monitors, liquid crystal televisions, and other display devices or dimming films. In addition, the liquid crystal element formed using the liquid crystal alignment agent of the present invention can also be applied to phase difference films.

[Examples] The present invention is further described below in detail based on the examples, but the present invention is not limited to these examples.

The solution viscosity of each polymer solution in the synthesis example, the imidization ratio of polyimide, the weight average molecular weight, and the epoxy equivalent were measured by the following method. [Solution viscosity of polymer solution (mPa·s)] The solution adjusted to a polymer concentration of 10 wt% using a predetermined solvent was measured at 25°C using an E-type rotational viscometer. [Imidization ratio of polyimide] The solution of polyimide was poured into pure water, and the obtained precipitate was fully dried under reduced pressure at room temperature, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-nuclear magnetic resonance ( ¹ H-NMR) was measured at room temperature using tetramethylsilane as ^a reference substance. From the obtained ¹ H-NMR spectrum, the imidization rate [%] is calculated using the following formula (1). Imidization rate [%] = (1-A ¹ /A ² × α) × 100… (1) (In formula (1), A ¹ is the peak area due to the proton of the NH group appearing around the chemical shift of 10 ppm, A ² is the peak area due to other protons, and α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamine)) [The weight average molecular weight Mw of the polymer] is a polystyrene conversion value measured by gel permeation chromatography under the following conditions. Column: TSKgelGRCXLII manufactured by Tosoh Co., Ltd. Solvent: Tetrahydrofuran Temperature: 40°C Pressure: 68 kgf/cm ² [Epoxide equivalent] Measured by the hydrochloric acid-methyl ethyl ketone method described in Japanese Industrial Standards (JIS) C 2105.

<Synthesis of polymer> [Synthesis Example 1: Synthesis of polyimide (PI-1)] 22.4 g (0.1 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride (TCA) as tetracarboxylic dianhydride, 8.6 g (0.08 mol) of p-phenylenediamine (PDA) as diamine, and 10.5 g (0.02 mol) of 3,5-diaminobenzoic acid cholesteryl ester (HCDA) were dissolved in 166 g of N-methyl-2-pyrrolidone (NMP) and reacted at 60°C for 6 hours to obtain a solution containing 20% by weight of polyimide. A small amount of the obtained polyimide solution was taken and NMP was added to prepare a solution having a polyimide concentration of 10% by weight. The viscosity of the solution was measured to be 90 mPa·s. Next, NMP was added to the obtained polyamide solution to prepare a solution with a polyamide concentration of 7 wt%, and 11.9 g of pyridine and 15.3 g of acetic anhydride were added to carry out a dehydration ring-closing reaction at 110°C for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new NMP (the pyridine and acetic anhydride used in the dehydration ring-closing reaction were removed from the system by this operation. The same applies hereinafter), thereby obtaining a solution containing 26 wt% of polyimide (PI-1) with an imidization rate of about 68%. A small amount of the obtained polyimide solution was taken, and NMP was added to prepare a solution with a polyimide concentration of 10 wt%. The viscosity of the solution was measured to be 45 mPa·s. Then, the reaction solution was injected into excess methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40°C for 15 hours under reduced pressure to obtain polyimide (PI-1).

[Synthesis Example 2: Synthesis of polyimide (PI-2)] 22.5 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 7.6 g (0.07 mol) of PDA as diamine, 5.2 g (0.01 mol) of HCDA, and 4.0 g (0.02 mol) of 4,4'-diaminodiphenylmethane (DDM) were dissolved in 157 g of NMP and reacted at 60°C for 6 hours to obtain a solution containing 20% by weight of polyimide. A small amount of the obtained polyimide solution was taken and NMP was added to prepare a solution with a polyimide concentration of 10% by weight. The viscosity of the solution was measured to be 110 mPa·s. Next, NMP was added to the obtained polyamide solution to prepare a solution with a polyamide concentration of 7 wt%, and 16.6 g of pyridine and 21.4 g of acetic anhydride were added to carry out a dehydration and ring-closing reaction at 110°C for 4 hours. After the dehydration and ring-closing reaction, the solvent in the system was replaced with new NMP, thereby obtaining a solution containing 26 wt% of polyimide (PI-2) with an imidization rate of about 82%. A small amount of the obtained polyimide solution was taken, and NMP was added to prepare a solution with a polyimide concentration of 10 wt%. The viscosity of the solution was measured to be 62 mPa·s. Next, the reaction solution was injected into excess methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40°C for 15 hours under reduced pressure to obtain polyimide (PI-2).

[Synthesis Example 3: Synthesis of polyimide (PI-3)] 24.9 g (0.10 mol) of bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid 2:4,6:8-dianhydride (BODA) as tetracarboxylic dianhydride, 8.6 g (0.08 mol) of PDA as diamine, and 10.4 g (0.02 mol) of HCDA were dissolved in 176 g of NMP and reacted at 60°C for 6 hours to obtain a solution containing 20% by weight of polyimide. A small amount of the obtained polyimide solution was taken and NMP was added to prepare a solution with a polyimide concentration of 10% by weight. The viscosity of the solution was measured to be 103 mPa·s. Then, NMP was added to the obtained polyamide solution to prepare a solution with a polyamide concentration of 7 wt%, and 11.9 g of pyridine and 15.3 g of acetic anhydride were added to carry out a dehydration and ring-closing reaction at 110°C for 4 hours. After the dehydration and ring-closing reaction, the solvent in the system was replaced with new NMP, thereby obtaining a solution containing 26 wt% of polyimide (PI-3) with an imidization rate of about 71%. A small amount of the obtained polyimide solution was taken, and NMP was added to prepare a solution with a polyimide concentration of 10 wt%. The viscosity of the solution was measured to be 57 mPa·s. Then, the reaction solution was injected into excess methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40°C for 15 hours under reduced pressure to obtain polyimide (PI-3).

[Synthesis Example 4: Synthesis of polyimide (PI-4)] 110 g (0.50 mol) of TCA as tetracarboxylic dianhydride and 160 g (0.50 mol) of 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione, 91 g (0.85 mol) of PDA as diamine, 25 g (0.10 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 25 g (0.040 mol) of 3,6-bis(4-aminobenzyloxy)cholestane, and 1.4 g (0.015 mol) of aniline as monoamine were dissolved in NMP 960. g, and reacted at 60°C for 6 hours to obtain a solution containing polyamide. A small amount of the obtained polyamide solution was taken, and NMP was added to prepare a solution with a polyamide concentration of 10% by weight. The measured solution viscosity was 60 mPa·s. Then, 2,700 g of NMP was added to the obtained polyamide solution, and 390 g of pyridine and 410 g of acetic anhydride were added to carry out a dehydration and ring-closing reaction at 110°C for 4 hours. After the dehydration and ring-closing reaction, the solvent in the system was replaced with new γ-butyrolactone, thereby obtaining a solution of about 2,500 g containing 15% by weight of polyimide (PI-4) with an imidization rate of about 95%. A small amount of the solution was taken and NMP was added to prepare a solution with a polyimide concentration of 10 wt%. The viscosity of the solution was measured to be 70 mPa·s. Then, the reaction solution was injected into excess methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40°C for 15 hours under reduced pressure to obtain polyimide (PI-4).

[Synthesis Example 5: Synthesis of polyimide (PI-5)] 22.4 g (0.1 mol) of TCA as tetracarboxylic dianhydride, 8.6 g (0.08 mol) of PDA as diamine, 2.0 g (0.01 mol) of DDM, and 3.2 g (0.01 mol) of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl were dissolved in 324 g of NMP and reacted at 60°C for 4 hours to obtain a solution containing 10% by weight of polyimide. Then, 360 g of NMP was added to the obtained polyimide solution, and 39.5 g of pyridine and 30.6 g of acetic anhydride were added to carry out a dehydration ring-closing reaction at 110°C for 4 hours. After the dehydration and ring-closing reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 10% by weight of polyimide (PI-5) with an imidization rate of about 93%. A small amount of the obtained polyamide solution was taken and the solution viscosity was measured to be 30 mPa·s. Then, the reaction solution was injected into excess methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40°C for 15 hours under reduced pressure to obtain polyimide (PI-5).

[Synthesis Example 6: Synthesis of polyimide (PI-6)] A polyimide solution was obtained by the same method as in Synthesis Example 1 except that the diamine used was changed to 0.08 mol of 3,5-diaminobenzoic acid (3,5DAB) and 0.02 mol of cholesteryloxy-2,4-diaminobenzene (HCODA). A small amount of the obtained polyimide solution was taken, and NMP was added to prepare a solution with a polyimide concentration of 10 wt %, and the measured solution viscosity was 80 mPa·s. Then, imidization was carried out by the same method as in Synthesis Example 1 to obtain a solution containing 26 wt % of polyimide (PI-6) with an imidization rate of about 65%. A small amount of the obtained polyimide solution was taken and NMP was added to prepare a solution with a polyimide concentration of 10% by weight. The viscosity of the solution was measured to be 40 mPa·s. Then, the reaction solution was injected into excess methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40°C for 15 hours under reduced pressure to obtain polyimide (PI-6).

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

[Synthesis Example 8: Synthesis of polyamide (PA-2)] The tetracarboxylic dianhydride used was set to 0.9 mol of pyromellitic dianhydride (PMDA) and 0.1 mol of CB, and the diamine was set to 0.2 mol of PDA and 0.8 mol of 4,4'-diaminodiphenyl ether (DDE). A polyamide solution having a solid content concentration of 10% by weight and a solution viscosity of 170 mPa·s was obtained by the same method as in Synthesis Example 7. Then, the polyamide solution was injected into excess methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40°C for 15 hours under reduced pressure to obtain polyamide (PA-2).

[Synthesis Example 9: Synthesis of polyamide (PA-3)] 7.0 g (0.031 mol) of TCA as tetracarboxylic dianhydride and 13 g (equivalent to 1 mol relative to 1 mol of TCA) of the compound represented by the following formula (R-1) as diamine were dissolved in 80 g of NMP and reacted at 60°C for 4 hours to obtain a solution containing 20% by weight of polyamide (PA-3). The solution viscosity of the polyamide solution was 2,000 mPa·s. In addition, the compound represented by the following formula (R-1) was synthesized according to the description of Japanese Patent Publication No. 2011-100099. Then, the polyamide solution was injected into excess methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40° C. for 15 hours under reduced pressure to obtain polyamine (PA-3). [Chemical 6]

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

[Synthesis Example 11: Synthesis of polyorganosiloxane (PS1)] In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux cooling tube, 31 g of p-phenylenedimethoxysilane, 70 g of tetrahydrofuran, 33 g of triethylamine, and 25 g of deionized water were added and mixed at room temperature. Then, the mixture was reacted at 60°C for 3 hours while stirring under reflux. After the reaction was completed, the organic layer was taken out, 60 g of diethylene glycol diethyl ether was added, and the mixture was heated and concentrated. The mixture was concentrated until the solid content reached 30%, thereby obtaining a diethylene glycol diethyl ether solution of polyorganosiloxane (PS1). [Synthesis Example 12, Synthesis Example 13] The input raw materials were set as shown in Table 1 below, and diethylene glycol diethyl ether solutions of polyorganosiloxane (PS2) and polyorganosiloxane (PS3) were obtained by the same synthesis method as Synthesis Example 11. The weight average molecular weight Mw of the obtained polyorganosiloxane is shown in Table 1 below.

[Table 1] Raw material silane compound [g] Polysiloxane STTMS ECETMS PTMS Name M Synthesis Example 11 32 0 0 PS1 4000 Synthesis Example 12 10 twenty two 0 PS2 3600 Synthesis Example 13 0 0 32 PS3 4100

In addition, in Table 1, the abbreviations of the raw material silane compounds have the following meanings. STTMS: p-phenyltrimethoxysilane ECETMS: 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane PTMS: phenyltrimethoxysilane

[Example 1] <Preparation of liquid crystal alignment agent> Using polyimide (PI-1) as a polymer, trimethyl phosphate (PTM), N-methyl-2-pyrrolidone (NMP) and butyl solvent (BC) as solvents were added thereto to prepare a solution having a solvent composition of PTM:NMP:BC = 20:40:40 (weight ratio) and a solid content of 6.5 wt%. The solution was filtered using a filter with a pore size of 1 μm to prepare a liquid crystal alignment agent (S-1). In addition, the liquid crystal alignment agent (S-1) is mainly used for the manufacture of vertical alignment type liquid crystal display elements.

<Evaluation of the swelling properties of the printing plate> The swelling ease (swelling properties) of the APR plate was evaluated using the liquid crystal alignment agent (S-1). The APR plate is a resin plate formed by partially curing a liquid photosensitive resin by ultraviolet irradiation, and is generally used in the printing plates of liquid crystal alignment film printers. The fact that the APR plate is not easy to swell when the liquid crystal alignment agent is in contact with the APR plate means that the liquid crystal alignment agent is not easy to penetrate into the APR plate during printing and the printing properties are good. The swelling properties are evaluated by immersing the APR plate in the liquid crystal alignment agent for one day and measuring the weight change of the APR plate before and after the immersion. At this time, when the weight increase rate (swelling rate) of the APR plate is less than 4%, the APR plate is not easy to swell and is evaluated as good (○), and when the increase rate is more than 4%, the APR plate is easy to swell and is evaluated as poor (×). As a result, in the embodiment, the swelling rate is 3.5%, and the swelling characteristics are "good (○)". The swelling rate is calculated using the following formula (2). Swelling rate [%] = (W ² -W ¹ )/W ¹ ) × 100... (2) (In formula (2), W ¹ is the weight of the APR plate before immersion, and W ² is the weight of the APR plate after immersion)

<Evaluation of Printability> The printability (continuous printability) of the prepared liquid crystal alignment agent (S-1) was evaluated when printing on a substrate continuously. The evaluation was performed as follows. First, a liquid crystal alignment film printer (manufactured by Nippon Shashin Printing Co., Ltd., Angstrom type "S40L-532") was used to print on the transparent electrode surface of a glass substrate with a transparent electrode including an ITO film, with the amount of liquid crystal alignment agent (S-1) added to the anilox roll set to 20 drops (about 0.2 g) back and forth. Printing on the substrate was performed 20 times while using a new substrate at intervals of 1 minute. Next, the liquid crystal alignment agent (S-1) is distributed (single pass) onto the anilox roll at intervals of 1 minute, and then the operation of bringing the anilox roll into contact with the printing plate (hereinafter referred to as idle operation) is performed a total of 10 times (no printing is performed on the glass substrate during this period). In addition, the idle operation is an operation performed intentionally to print the liquid crystal alignment agent under severe conditions. After 10 idle operations, the glass substrate is used for formal printing. In formal printing, 5 substrates are put in at intervals of 30 seconds after the idle operation, and each printed substrate is heated at 80°C for 1 minute (pre-baking) to remove the solvent, and then heated at 200°C for 10 minutes (post-baking) to form a coating with a film thickness of about 80 nm. The coating was observed through a microscope with a magnification of 20 times to evaluate the printability (continuous printability). In the evaluation, the case where no polymer precipitation was observed in the first formal printing after the idling was regarded as "good (○)" for continuous printability, the case where polymer precipitation was observed in the first formal printing after the idling but no polymer precipitation was observed during the 5th formal printing was regarded as "acceptable (△)" for continuous printability, and the case where polymer precipitation was still observed after the formal printing was repeated 5 times was regarded as "poor (×)" for continuous printability. As a result, the continuous printability in the embodiment was "good (○)". In addition, it was found from the experiment that in the liquid crystal alignment agent with good printability, the polymer precipitation became better (disappeared) during the continuous input of the substrate. In addition, the number of idle runs was changed to 15, 20, and 25 times, and the printability of the liquid crystal alignment agent was evaluated in the same manner as described above. As a result, in the embodiment described above, when the idle runs were set to 15 and 20 times, they were "good (○)", and when they were set to 25 times, they were "acceptable (△)".

[Example 2 to Example 31 and Comparative Example 1 to Comparative Example 5] Except that the types and components of the polymers and solvents used were changed as shown in Table 2 below, liquid crystal alignment agents (S-2) to (S-31) and liquid crystal alignment agents (SR-1) to (SR-5) were prepared in the same manner as in Example 1. In addition, the swelling characteristics and printability of the printing plate of each liquid crystal alignment agent were evaluated in the same manner as in Example 1. The results of these evaluations are shown in Table 2 below.

[Table 2] The composition of the distributing agent Swelling properties Printability evaluation (extraction evaluation) Types of directional agents Polymer composition (weight ratio) Solvent composition (weight ratio) Swelling rate (%) result 10 times 15 times 20 times 25 times Embodiment 1 S-1 PI-1 a/d/j=20/40/40 3.5 ○ ○ ○ ○ △ Embodiment 2 S-2 PI-1 b/d/j=20/40/40 3.7 ○ ○ ○ ○ ○ Embodiment 3 S-3 PI-1 b/d/j=40/30/30 3.5 ○ ○ ○ ○ ○ Embodiment 4 S-4 PI-1 c/d/j=40/20/40 3.9 ○ ○ ○ ○ ○ Embodiment 5 S-5 PI-1 b/e/j=20/40/40 3.6 ○ ○ ○ ○ ○ Embodiment 6 S-6 PI-1 b/f/j=20/40/40 3.6 ○ ○ ○ ○ △ Embodiment 7 S-7 PI-1 b/g/j=40/30/30 3.5 ○ ○ ○ ○ △ Embodiment 8 S-8 PI-1 b/h/j=40/30/30 3.5 ○ ○ ○ ○ ○ Embodiment 9 S-9 PI-1 b/i/j=40/30/30 3.6 ○ ○ ○ ○ ○ Embodiment 10 S-10 PI-1 b/d/k=40/30/30 3.5 ○ ○ ○ ○ △ Embodiment 11 S-11 PI-1 b/d/l=40/30/30 3.5 ○ ○ ○ ○ △ Embodiment 12 S-12 PI-2 b/d/j=40/30/30 3.6 ○ ○ ○ ○ △ Embodiment 13 S-13 PI-2 b/h/j=40/30/30 3.5 ○ ○ ○ ○ △ Embodiment 14 S-14 PI-2 b/i/j=40/30/30 3.6 ○ ○ ○ ○ △ Embodiment 15 S-15 PI-3 b/d/j=40/30/30 3.7 ○ ○ ○ ○ △ Embodiment 16 S-16 PI-3 b/h/j=40/30/30 3.5 ○ ○ ○ ○ △ Embodiment 17 S-17 PI-3 b/i/j=40/30/30 3.6 ○ ○ ○ ○ △ Embodiment 18 S-18 PI-4/PA-1=20/80 b/d/j=30/50/20 3.7 ○ ○ ○ ○ ○ Embodiment 19 S-19 PI-4/PA-1=20/80 b/h/j=30/50/20 3.6 ○ ○ ○ ○ ○ Embodiment 20 S-20 PI-4/PA-1=20/80 b/i/j=30/50/20 3.6 ○ ○ ○ ○ ○ Embodiment 21 S-21 PI-4/PA-1=20/80 c/d/j=30/50/20 3.9 ○ ○ ○ ○ ○ Embodiment 22 S-22 PI-4/PA-1=20/80 c/h/j=30/50/20 3.7 ○ ○ ○ ○ ○ Embodiment 23 S-23 PI-4/PA-1=20/80 c/i/j=30/50/20 3.8 ○ ○ ○ ○ ○ Embodiment 24 S-24 PI-5/PA-2=40/60 b/d/j=30/50/20 3.7 ○ ○ ○ ○ ○ Embodiment 25 S-25 PI-6/APS-1=95/5 b/d/k=30/20/50 3.5 ○ ○ ○ ○ ○ Embodiment 26 S-26 PI-6/APS-1=95/5 b/d/j=40/20/40 3.6 ○ ○ ○ ○ ○ Embodiment 27 S-27 PI-6/APS-1=95/5 b/d/k=40/20/40 3.4 ○ ○ ○ ○ △ Embodiment 28 S-28 PI-6/APS-1=95/5 b/d/l=40/20/40 3.4 ○ ○ ○ ○ △ Embodiment 29 S-29 PA-3/PA-1=30/70 b/d/j=40/20/40 3.5 ○ ○ ○ ○ ○ Embodiment 30 S-30 PA-3/PA-1=30/70 b/j=60/40 3.3 ○ ○ ○ ○ ○ Embodiment 31 S-31 PA-3/PA-1=30/70 c/j=60/40 3.4 ○ ○ ○ ○ ○ Comparison Example 1 SR-1 PI-1 d=100 3.0 ○ ○ △ × × Comparison Example 2 SR-2 PI-1 d/j=50/50 4.8 × ○ ○ ○ △ Comparison Example 3 SR-3 PI-1 d/l=50/50 3.5 ○ ○ △ × × Comparison Example 4 SR-4 PI-1 e/j=50/50 4.9 × ○ ○ ○ △ Comparison Example 5 SR-5 PI-1 d/l=50/50 5.6 × ○ ○ ○ △

In Table 2, for the cases where two polymers are used as polymer components (Examples 18 to 31), the usage ratio (weight ratio) of each polymer relative to 100 parts by weight of the total volume of the polymers used is shown. Among the liquid crystal alignment agents, (S-2) to (S-17), (SR-1) to (SR-5) are mainly used for the production of vertical alignment type liquid crystal display elements, (S-18) to (S-23) are mainly used for the production of TN type liquid crystal display elements, (S-24) is mainly used for the production of IPS liquid crystal display elements, and (S-29) to (S-31) are mainly used for the production of vertical alignment type liquid crystal display elements using a photoalignment method, and (S-25) to (S-28) are mainly used for the production of PSA type liquid crystal display elements. In Table 2, the numerical values of the solvent composition represent the mixing ratio (weight ratio) of each compound relative to the total amount of the solvent used in the preparation of the liquid crystal alignment agent (the same applies to Tables 3 to 5 below). The symbols of the solvent composition have the following meanings. a: trimethyl phosphate b: triethyl phosphate c: hexamethylphosphotriamide d: N-methyl-2-pyrrolidone e: N-ethyl-2-pyrrolidone f: γ-butyrolactone g: γ-valerolactone h: δ-valerolactone i: N,N-diethylacetamide j: butyl solvent k: diethylene glycol diethyl ether l: propylene glycol monomethyl ether acetate

[Example 32 to Example 52] Except that the types and components of the polymer and solvent used were changed as shown in Table 3 below, liquid crystal alignment agents (S-32) to liquid crystal alignment agents (S-52) were prepared in the same manner as in Example 1. In addition, the swelling characteristics and printability of the printing plate were evaluated in the same manner as in Example 1 for each liquid crystal alignment agent. The results of these evaluations are shown in Table 3 below.

[Table 3] The composition of the distributing agent Swelling properties Printability evaluation (extraction evaluation) Types of directional agents Polymer composition (weight ratio) Solvent composition (weight ratio) Swelling rate (%) result 10 times 15 times 20 times 25 times Embodiment 32 S-32 PI-1 d/m/j=20/40/40 3.7 ○ ○ ○ ○ ○ Embodiment 33 S-33 PI-1 m/j=60/40 3.6 ○ ○ ○ ○ ○ Embodiment 34 S-34 PI-1 d/n/j=20/40/40 3.6 ○ ○ ○ ○ ○ Embodiment 35 S-35 PI-1 n/j=60/40 3.5 ○ ○ ○ ○ ○ Embodiment 36 S-36 PI-1 d/o/j=20/40/40 3.7 ○ ○ ○ ○ ○ Embodiment 37 S-37 PI-1 o/j=60/40 3.6 ○ ○ ○ ○ ○ Embodiment 38 S-38 PI-1 d/p/j=20/40/40 3.5 ○ ○ ○ ○ △ Embodiment 39 S-39 PI-1 p/j=60/40 3.4 ○ ○ ○ ○ △ Embodiment 40 S-40 PI-4/PA-1=20/80 d/m/j=20/40/40 3.6 ○ ○ ○ ○ ○ Embodiment 41 S-41 PI-4/PA-1=20/80 d/n/j=20/40/40 3.5 ○ ○ ○ ○ ○ Embodiment 42 S-42 PI-4/PA-1=20/80 d/o/j=20/40/40 3.5 ○ ○ ○ ○ ○ Embodiment 43 S-43 PI-4/PA-1=20/80 d/p/j=20/40/40 3.4 ○ ○ ○ ○ △ Embodiment 44 S-44 PI-1 d/r/j=20/40/40 3.7 ○ ○ ○ ○ ○ Embodiment 45 S-45 PI-1 r/j=60/40 3.6 ○ ○ ○ ○ ○ Embodiment 46 S-46 PI-1 d/s/j=20/40/40 3.6 ○ ○ ○ △ △ Embodiment 47 S-47 PI-1 s/j=60/40 3.5 ○ ○ ○ △ △ Embodiment 48 S-48 PI-1 d/t/j=20/40/40 3.6 ○ ○ ○ △ △ Embodiment 49 S-49 PI-1 t/j=60/40 3.5 ○ ○ ○ △ △ Embodiment 50 S-50 PI-4/PA-1=20/80 d/r/j=20/40/40 3.6 ○ ○ ○ ○ ○ Embodiment 51 S-51 PI-4/PA-1=20/80 d/s/j=20/40/40 3.5 ○ ○ ○ △ △ Embodiment 52 S-52 PI-4/PA-1=20/80 d/t/j=20/40/40 3.5 ○ ○ ○ △ △

In Table 3, for those using two polymers as polymer components (Examples 40 to 43, Examples 50 to 52), the usage ratio (weight ratio) of each polymer relative to 100 parts by weight of the total volume of the polymers used is shown together. In addition, among the liquid crystal alignment agents, (S-32) to (S-39), (S-44) to (S-49) are mainly used for the manufacture of vertical alignment type liquid crystal display elements, and (S-40) to (S-43), (S-50) to (S-52) are mainly used for the manufacture of TN type liquid crystal display elements. In Table 3, the symbols of the solvent composition have the following meanings. d and j are the same as those in Table 2. m: N,N-dimethylpropylurea n: 4-methylmorpholine o: 3-methyl-2-oxazolidinone p: tetrahydro-4H-pyran-4-one r: tetramethylene sulfone s: 3-methylcyclohexanone t: 4-methylcyclohexanone

[Example 53 to Example 56] Except that the polymer components and the types and components of the solvents used were changed as shown in Table 4 below, liquid crystal alignment agents (S-53) to liquid crystal alignment agents (S-56) were prepared respectively by the same method as in Example 1. In addition, for each liquid crystal alignment agent, the swelling characteristics and printability of the printing plate were evaluated in the same manner as in Example 1. The results of these evaluations are shown in Table 4 below.

[Table 4] The composition of the distributing agent Swelling properties Printability evaluation (extraction evaluation) Types of directional agents Polymer composition (weight ratio) Solvent composition (weight ratio) Swelling rate (%) result 10 times 15 times 20 times 25 times Embodiment 53 S-53 PI-1 d/q/j=20/40/40 3.5 ○ ○ ○ △ △ Embodiment 54 S-54 PI-1 q/j=60/40 3.4 ○ ○ ○ △ △ Embodiment 55 S-55 PI-4/PA-1=20/80 d/q/j=20/40/40 3.5 ○ ○ ○ △ △ Embodiment 56 S-56 PI-4/PA-1=20/80 d/u/j=30/40/30 3.3 ○ ○ ○ △ △

In Table 4, for those using two polymers as polymer components (Example 55, Example 56), the usage ratio (weight ratio) of each polymer relative to 100 parts by weight of the total volume of the polymers used is shown. In addition, among the liquid crystal alignment agents, (S-53) and (S-54) are mainly used for the manufacture of vertical alignment type liquid crystal display elements, and (S-55) and (S-56) are mainly used for the manufacture of TN type liquid crystal display elements. In Table 4, the symbols of the solvent composition have the following meanings. d and j are the same as those in Table 2. q: 5-methyl-2-furfurylaldehyde u: N,N-dimethyllactamide (a compound represented by the following formula (10-1)) [Chemical 7]

[Example 57 to Example 60] The types and components of the polymers and solvents used were changed as shown in Table 5 below. In addition, liquid crystal alignment agents (S-57) to liquid crystal alignment agents (S-60) were prepared respectively using the same method as in Example 1. In addition, for each liquid crystal alignment agent, the swelling characteristics and printability of the printing plate were evaluated in the same manner as in Example 1. The results of these evaluations are shown in Table 5 below. In addition, in Table 5, the numerical values in the polymer component column represent the usage ratio (weight ratio) of each polymer relative to 100 parts by weight of the total volume of the polymers used. The symbols (d, m, j) of the solvent composition are the same as those in Tables 2 and 3. [Table 5] The composition of the distributing agent Swelling properties Printability evaluation (extraction evaluation) Types of directional agents Polymer composition (weight ratio) Solvent composition (weight ratio) Swelling rate (%) result 10 times 15 times 20 times 25 times Embodiment 57 S-57 PI-1/PS1=90/10 d/m/j=20/40/40 3.6 ○ ○ ○ ○ ○ Embodiment 58 S-58 PI-1/PS2=90/10 d/m/j=20/40/40 3.7 ○ ○ ○ ○ ○ Embodiment 59 S-59 PI-1/PS3=90/10 d/m/j=20/40/40 3.7 ○ ○ ○ ○ ○ Embodiment 60 S-60 PI-4/PA-1/PS1=20/75/5 d/m/j=20/40/40 3.6 ○ ○ ○ ○ ○

The results show that the liquid crystal alignment agents containing the specific solvent (Examples 1 to 60) are not likely to cause the printing plate to swell, and the continuous printing properties are also good. In contrast, the liquid crystal alignment agents of the comparative examples that do not contain the specific solvent have swelling characteristics and continuous printing properties that are worse than those of the examples.

without

without

Claims (5)

A liquid crystal alignment agent, comprising: a polymer component, and a specific solvent, which is tetrahydro-4H-pyran-4-one. The liquid crystal alignment agent as described in claim 1, wherein the polymer component contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane. In the liquid crystal alignment agent as claimed in claim 1 or claim 2, the content ratio of the specific solvent is 1 wt % to 80 wt % relative to the total volume of the solvent in the liquid crystal alignment agent. A liquid crystal alignment film is formed using the liquid crystal alignment agent as described in any one of claims 1 to 3. A liquid crystal element comprising the liquid crystal alignment film as described in claim 4.