CN103045270B - Crystal aligning agent, liquid crystal orienting film and liquid crystal display device - Google Patents

Abstract

The invention provides a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element. The storage stability of the said liquid crystal alignment agent is excellent, and the liquid crystal alignment film which can continue to display with high quality even when a liquid crystal display element is used for a long time can be manufactured. The above-mentioned liquid crystal alignment agent contains at least one polymer selected from the group consisting of polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine and polyimide obtained by dehydrating and ring-closing the polyamic acid. A liquid crystal alignment agent, characterized in that: the tetracarboxylic dianhydride contains bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, the bicyclo[2.2.1]heptane- The ratio of the isomer represented by the following formula (1) in 2,3,5,6-tetracarboxylic dianhydride is 70 mol% or more,

Description

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

technical field

The invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element, in particular to a liquid crystal alignment agent with excellent storage stability, especially excellent heat resistance, and a liquid crystal alignment agent capable of displaying with high quality and suppressing thermal stress Display degradation caused by long-term driving of liquid crystal display elements.

Background technique

The materials of the liquid crystal alignment film used in the liquid crystal display element include polyimide, polyamide, polyamic acid, polyester and other resin materials. Among them, liquid crystal alignment films made of polyamic acid or polyimide are excellent in heat resistance, mechanical strength, and affinity with liquid crystals, and are used in many liquid crystal display elements (Patent Document 1 to Patent Document 6).

Among them, polyamic acid has high solubility in general-purpose organic solvents, so it is possible to obtain a liquid crystal alignment agent that is easy to print in the manufacturing process of a liquid crystal display element, and has an advantage that the resin is inexpensive. However, a liquid crystal display element having a liquid crystal alignment film made of polyamic acid is vulnerable to thermal stress, and when the liquid crystal display element is driven for a long time, there is a problem that voltage retention decreases due to deterioration of the liquid crystal alignment film. In recent years, liquid crystal televisions, typified by liquid crystal televisions, have been designed on the assumption that the life of liquid crystal display elements exceeds 10 years. Therefore, in order to ensure high-quality display even when the liquid crystal display element is driven for a long time, it is important to exhibit a long-term stable voltage retention rate, and it is urgent to improve the heat resistance reliability of the alignment film. As a method for improving the heat resistance reliability (heat stress resistance) of an alignment film known so far, it has been proposed to increase the chemical stability of the liquid crystal alignment film by blending an epoxy compound in a liquid crystal alignment agent ( Patent Document 7); a method in which intermolecular crosslinks are formed when firing a liquid crystal alignment film by using a polyamic acid introduced with a monomer having a carboxylic acid, thereby increasing the stability of the film (Patent Document 8) and the like. However, if these technologies are used, it is necessary to use a large amount of epoxy compounds or carboxylic acids in order to exert the desired performance, which will impair the reworkability of the liquid crystal alignment film (easiness of peeling off the coating film when the liquid crystal alignment agent is poorly printed) ), friction resistance, etc., and need further improvement.

On the other hand, as a liquid crystal alignment film containing polyimide, although the thermal stress resistance of the obtained liquid crystal alignment film is relatively high, the solubility of previously known polyimides to general-purpose organic solvents is not sufficient, so Problems may arise in the storage stability of a liquid crystal aligning agent.

Based on such facts, polyamic acid/polyimide liquid crystal alignment agents that have sufficient solubility in general-purpose organic solvents and can form liquid crystal alignment films excellent in thermal stress resistance are required.

[Prior art literature]

[Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 4-153622

[Patent Document 2] Japanese Patent Laid-Open No. 60-107020

[Patent Document 3] Japanese Patent Laid-Open No. 11-258605

[Patent Document 4] Japanese Patent Laid-Open No. 56-91277

[Patent Document 5] Specification of US Patent No. 5,928,733

[Patent Document 6] Japanese Patent Laid-Open No. 62-165628

[Patent Document 7] Japanese Patent Laid-Open No. 2008-299318

[Patent Document 8] Japanese Patent Laid-Open No. 2009-157351

[Patent Document 9] Japanese Patent Laid-Open No. 2010-97188

[Patent Document 10] Japanese Patent Laid-Open No. 6-222366

[Patent Document 11] Japanese Patent Laid-Open No. 6-281937

[Patent Document 12] Japanese Patent Laid-Open No. 5-107544

[Non-patent literature]

[Non-Patent Document 1] Journal of Organic Chemistry (J.Org.Chem.), 57, 6075-6077 (1992)

Contents of the invention

The present invention is made in view of the above facts, and an object of the present invention is to provide a liquid crystal alignment agent that is excellent in storage stability and capable of producing a liquid crystal alignment that can sustain high-quality display even when the liquid crystal display element is driven for a long time membrane.

Another object of the present invention is to provide a liquid crystal display element capable of maintaining high-quality display even when it is driven for a long time.

Other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above-mentioned purpose and advantages of the present invention can firstly be achieved by the following liquid crystal alignment agent:

A liquid crystal alignment agent containing at least A polymer liquid crystal alignment agent, characterized in that:

The tetracarboxylic dianhydride comprises bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, the bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic The presence ratio of the isomer represented by the following formula (1) in the dianhydride is 70 mol% or more,

Above-mentioned purpose and advantage of the present invention can be reached secondly by following liquid crystal display element:

A liquid crystal display element is characterized in that it includes a liquid crystal alignment film formed by the above-mentioned liquid crystal alignment agent.

The effect of the invention

The liquid crystal alignment agent of this invention is excellent in storage stability, and can manufacture the liquid crystal alignment film which can display continuously high quality even if it drives it for a long time when using a liquid crystal display element. Therefore, the liquid crystal display element of this invention containing the liquid crystal alignment film formed from this liquid crystal alignment agent can continue to display with high quality even when it drives for a long time.

The liquid crystal display device of the present invention can be effectively applied to various devices, such as clocks, portable game machines, word processors, notebook computers, car navigation systems, camcorders, personal digital assistants, digital cameras, etc. , mobile phones, various monitors, LCD TVs and other display devices.

detailed description

As described above, the liquid crystal alignment agent of the present invention is composed of polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine and polyimide obtained by dehydrating and ring-closing the polyamic acid. A liquid crystal alignment agent of at least one polymer of the group, characterized in that:

The tetracarboxylic dianhydride comprises bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, the bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic The abundance ratio of the isomer represented by said formula (1) in a dianhydride is 70 mol% or more. In this specification, the group consisting of a polyamic acid obtained by reacting a specific tetracarboxylic dianhydride with a diamine and a polyimide obtained by dehydrating and ring-closing the polyamic acid may be used below. At least one polymer of the group is referred to as "specific polymer".

<Tetracarboxylic dianhydride>

Tetracarboxylic dianhydrides used to synthesize specific polymers in the present invention include bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, which bicyclo[2.2.1]heptane-2 , The abundance ratio of the isomer represented by the above formula (1) in 3,5,6-tetracarboxylic dianhydride is 70 mol% or more. The compound represented by the above formula (1) is a compound named bicyclo[2.2.1]heptane-2-endo, 3-endo, 5-exo, 6-exotetracarboxylic dianhydride.

The bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride in which the steric structure of the 2,3,5,6-position is not specific is known before. It is generally considered that the known compound is the isomer represented by the above-mentioned formula (1) and the isomer represented by the following formula (2) (bicyclo[2.2.1]heptane-2-exo, 3-exo, 5 -exo, 6-exotetracarboxylic dianhydride) in a roughly 1:1 mixture.

However, in recent years, a method for selectively producing only the isomer represented by the above formula (1) has been proposed. That is, according to Non-Patent Document 1 (Journal of Organic Chemistry (J.Org.Chem.), 57, 6075-6077 (1992)), the compound (isomer) represented by the above formula (1) can be obtained by the following scheme 1 and manufacture.

Process 1

The inventors of the present invention found that by using a specific polymer (the specific polymer uses a bicyclo[2.2.1]heptane-2,3 , 5,6-tetracarboxylic dianhydride (manufactured from tetracarboxylic dianhydride) as a polymer contained in a liquid crystal alignment agent can dramatically improve the long-term drive stability of the obtained liquid crystal display element, thus completing this paper. invention. This effect cannot be obtained by using the previously known bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride which is not stereoselective.

Presence of the isomer represented by the above formula (1) in bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride in tetracarboxylic dianhydride used to synthesize a specific polymer The ratio is preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 100 mol%.

The use ratio of bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride in the tetracarboxylic dianhydride used to synthesize the specific polymer (the isomer represented by the above formula (1) and the sum of the usage ratio of the isomer represented by the above formula (2)) is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more.

Therefore, the tetracarboxylic dianhydride used to synthesize a specific polymer may contain bicyclo[2.2.1]heptane-2 in a range of 95 mol% or less, preferably 90 mol% or less, more preferably 80 mol% or less. , Other tetracarboxylic dianhydrides other than 3,5,6-tetracarboxylic dianhydride.

As said other tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, etc. are mentioned, for example. As specific examples of these compounds, aliphatic tetracarboxylic dianhydrides, for example, include butane tetracarboxylic dianhydrides, etc.;

Alicyclic tetracarboxylic dianhydrides include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a,4, 5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a , 4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3- Diketone, 3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5- Dioxotetrahydro-3-furyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2 :3,5:6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, 4,9-dioxatricyclo[ 5.3.1.0 ^2,6 ]undecane-3,5,8,10-tetraketone, etc.;

Examples of aromatic tetracarboxylic dianhydride include pyromellitic dianhydride and the like;

In addition, the tetracarboxylic dianhydride described in patent document 9 (Japanese Unexamined Patent Application Publication No. 2010-97188) can also be used.

The above-mentioned other tetracarboxylic dianhydrides are preferably selected from the group consisting of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a,4, 5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a , 4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3- Diketone, 3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5- Dioxotetrahydro-3-furyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2 :3,5:6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride and 4,9-dioxatricyclo[ 5.3.1.0 At least one species from the group consisting of ^2,6 ]undecane-3,5,8,10-tetraketone (hereinafter referred to as "specific tetracarboxylic dianhydride").

The usage ratio of the said specific tetracarboxylic dianhydride is preferably 50 mol% or more, more preferably 80 mol% or more, and especially preferably 100 mol% with respect to the whole of the said other tetracarboxylic dianhydride.

The tetracarboxylic dianhydride used to synthesize the specific polymer in the present invention preferably only contains bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, or only bicyclo[2.2.1] Heptane-2,3,5,6-tetracarboxylic dianhydride and specific tetracarboxylic dianhydride.

<Diamine>

The diamine used for synthesizing the specific polymer in the present invention includes, for example, aliphatic diamine, alicyclic diamine, aromatic diamine, diaminoorganosiloxane, and the like. As specific examples of these compounds, aliphatic diamines include, for example, 1,3-m-xylylenediamine, 1,3-propylenediamine, butanediamine, pentamethylenediamine, hexamethylenediamine, etc.;

Alicyclic diamines include, for example, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), 1,3-bis(aminomethyl)cyclohexane, etc.;

Examples of aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylamine, 1, 5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 2, 7-diaminofluorene, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 9,9-bis(4-aminophenyl ) fluorene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4′-(p-phenylene Diisopropylidene) bisaniline, 4,4'-(m-phenylene diisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis( 4-aminophenoxy)biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarba Azole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N,N'-bis (4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, 1,4-bis-(4-aminophenyl)- Piperazine, 3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2 , 4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, 3,5-diaminobenzoic acid cholestyl ester, 3,5-diaminobenzoic acid cholestyl ester, 3,5-diaminobenzoic acid lanostanyl ester, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 4-(4'-trifluoromethylbenzoyloxy)cyclohexyl- 3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl) Base)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1 - bis(4-((aminophenyl)methyl)phenyl)-4-(4-heptylcyclohexyl)cyclohexane and compounds represented by the following formula (A-1), etc.,

In formula (A-1), X ^I is alkylene with 1 to 3 carbons, ^* -O-, ^* -COO- or ^* -OCO- (wherein, the bond with "*" and diaminobenzene base bond), a is 0 or 1, b is an integer of 0 to 2, and c is an integer of 1 to 20;

Diaminoorganosiloxane, for example, 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, etc.,

Other diamines described in Patent Document 9 (Japanese Patent Laid-Open No. 2010-97188 ) can be used.

X ^I in the above formula (A-1) is preferably an alkylene group having 1 to 3 carbon atoms, ^* -O- or ^* -COO- (wherein, the bond with "*" is bonded to a diaminophenyl group) . Specific examples of the group C _c H _2c+1 - include, for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl , n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n- eicosyl etc. Preferably, the two amino groups in the diaminophenyl group are at the 2,4-position or the 3,5-position with respect to other groups.

Specific examples of the compound represented by the above formula (A-1) include dodecyloxy-2,4-diaminobenzene, tetradecyloxy-2,4-diaminobenzene, pentadecyloxy -2,4-diaminobenzene, hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, dodecyloxy-2,5-diaminobenzene , tetradecyloxy-2,5-diaminobenzene, pentadecyloxy-2,5-diaminobenzene, hexadecyloxy-2,5-diaminobenzene, octadecyloxy-2 , 5-diaminobenzene, compounds represented by the following formulas (A-1-1) to (A-1-3), and the like.

In the above formula (A-1), it is preferable that a and b are not 0 at the same time.

The above-mentioned diamines preferably comprise p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2'- Dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diaminodiphenylamine and 4 , at least one of the group consisting of 4'-(m-phenylene diisopropylidene) diphenylamine (hereinafter referred to as "specific diamine 1").

Moreover, when the liquid crystal alignment agent of the present invention is used to form a liquid crystal alignment film in a vertical alignment type (VA type) liquid crystal display element, it is preferable to further contain a cholestyl group selected from the above-mentioned specific diamine Oxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2, 4-diaminobenzene, 3,5-diaminobenzoic acid cholestyl group, 3,5-diaminobenzoic acid cholestyl group, 3,5-diaminobenzoic acid lanostyl group, 3,6-bis At least 1 of the group consisting of (4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane and the compound represented by the above formula (A-1) species (hereinafter referred to as "specific diamine 2").

When the liquid crystal alignment agent of the present invention is used to form a liquid crystal alignment film in a VA-type vertical alignment type liquid crystal display element, the preferred usage ratio of the above-mentioned specific diamine 1 and specific diamine 2 relative to all diamines is as follows .

Specific diamine 1: preferably 20 mol% to 97 mol%, more preferably 50 mol% to 95 mol%, particularly preferably 60 mol% to 90 mol%

Specific diamine 2: preferably 3 mol% to 80 mol%, more preferably 5 mol% to 50 mol%, particularly preferably 10 mol% to 40 mol%

In this case, it is preferable to make the total usage ratio of the said specific diamine 1 and the specific diamine 2 into 100 mol% with respect to all diamines.

On the other hand, the liquid crystal alignment agent of the present invention is used to form liquid crystal display elements other than VA type (such as twisted nematic (Twisted Nematic, TN) type, super twisted nematic (Super Twisted Nematic, STN) type, transverse electric field (such as common In the case of a liquid crystal alignment film in plane switching (In-PlaneSwitching, IPS), fringe field switching (FringeFieldSwitching, FFS, etc.), the preferred usage ratio of the above-mentioned specific diamine 1 and specific diamine 2 to all diamines is as follows mentioned.

Specific diamine 1: preferably 50 mol% or more, more preferably 80 mol% or more, particularly preferably 100 mol%

Specific diamine 2: preferably 30 mol% or less, more preferably 10 mol% or less, particularly preferably 0 mol%

In this case, as a diamine, it is preferable to make the total of the said specific diamine 1 and the specific diamine 2 into 100 mol%, and it is more preferable to use only the specific diamine 1.

<Molecular weight regulator>

When synthesizing the above-mentioned polyamic acid, it is also possible to synthesize an end-modified polymer using an appropriate molecular weight modifier together with the above-mentioned tetracarboxylic dianhydride and diamine. Liquid crystal alignment comprising at least one polymer selected from the group consisting of the polyamic acid and a polyimide obtained by dehydrating and ring-closing the polyamic acid as the terminal-modified polymer The agent can further improve the applicability (printability) without impairing the effect of the present invention.

Examples of the molecular weight modifier include acid monoanhydrides, monoamine compounds, monoisocyanate compounds, and the like. Specific examples of these compounds include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, N-hexadecyl succinic anhydride, etc.;

Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, etc.;

As a monoisocyanate compound, phenyl isocyanate, naphthyl isocyanate, etc. are mentioned, for example.

It is preferable that the usage ratio of a molecular weight modifier is 20 weight part or less with respect to the total 100 weight part of tetracarboxylic dianhydride and diamine used, and it is more preferable that it is 10 weight part or less.

<Synthesis of polyamic acid>

As the usage ratio of tetracarboxylic dianhydride and diamine used in the synthesis reaction of polyamic acid, it is preferable that the acid anhydride group of tetracarboxylic dianhydride is 0.2 to 2 equivalents with respect to 1 equivalent of amino groups of diamine. , more preferably in a ratio of 0.3 equivalents to 1.2 equivalents.

The synthesis reaction of polyamic acid is preferably carried out in an organic solvent at preferably -20°C to 150°C, more preferably 0 to 100°C, preferably for 0.1 to 24 hours, more preferably for 0.5 to 12 hours.

Here, examples of the organic solvent include aprotic polar solvents, phenols and derivatives thereof, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like.

As specific examples of these organic solvents, the aforementioned aprotic polar solvents include, for example, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphoric triamide, etc.;

The above-mentioned phenol derivatives include, for example, m-cresol, xylenol, halogenated phenol, etc.;

The aforementioned alcohols include, for example, methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, etc.;

The above-mentioned ketones include, for example, acetone, butanone, methyl isobutyl ketone, cyclohexanone, etc.;

Examples of the above-mentioned esters include ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, ethyl ester, etc.;

The aforementioned ethers include, for example, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether Ester, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether Acetate, tetrahydrofuran, etc.;

The above-mentioned halogenated hydrocarbons include, for example, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, etc.;

Examples of the hydrocarbons include hexane, heptane, octane, benzene, toluene, xylene, isoamyl propionate, isoamyl isobutyrate, and diisoamyl ether.

Among these organic solvents, it is preferable to use at least one selected from the group consisting of aprotic polar solvents, phenols, and derivatives thereof (organic solvents of the first group), or to use one or more solvents selected from the first group. A mixture of one or more organic solvents and one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (organic solvents of the second group). In the latter case, with respect to the total of the organic solvents of the first group and the organic solvents of the second group, the use ratio of the organic solvent of the second group is preferably 50% by weight or less, more preferably 40% by weight. % by weight or less, more preferably 30% by weight or less.

The amount (a) of the organic solvent used is preferably an amount such that the total amount (b) of tetracarboxylic dianhydride and diamine becomes 0.1% by weight to 50% by weight with respect to the total amount of the reaction solution (a+b). % amount.

The reaction solution which melt|dissolved polyamic acid was obtained as mentioned above.

The reaction solution can be directly supplied to the preparation of the liquid crystal alignment agent, or the polyamic acid contained in the reaction solution can be isolated and then supplied to the preparation of the liquid crystal alignment agent, or the isolated polyamic acid can be purified and then supplied to the liquid crystal alignment agent modulation. When the polyamic acid is dehydrated and ring-closed to produce a polyimide, the above-mentioned reaction solution may be directly subjected to the dehydration-ring-closing reaction, or the polyamic acid contained in the reaction solution may be isolated and then subjected to the dehydration-ring-closing reaction. , or the isolated polyamic acid is subjected to a dehydration ring-closure reaction after purification. The isolation and purification of polyamic acid can be performed according to a well-known method.

<Synthesis of polyimide>

The polyimide can be obtained by dehydrating and ring-closing the polyamic acid synthesized as described above for imidization.

The polyimide in the present invention can be the complete imide formed by the dehydration and ring closure of the amic acid structure of the polyamic acid as its precursor, or it can be only a part of the amic acid structure dehydration ring closure, amic acid A partial imide compound with a structure that coexists with an imide ring structure. The polyimide in the present invention preferably has an imidization rate of 30% or more, more preferably 50% or more, particularly preferably 55% or more. This imidization ratio represents the ratio of the number of imide ring structures with respect to the sum total of the number of amic acid structures and the number of imide ring structures of a polyimide by percentage. Here, a part of the imide ring may be an isoimide ring.

The dehydration and ring closure of polyamic acid is preferably carried out by the following method: the method of heating polyamic acid; or dissolving polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution and heating as necessary method. Among them, the latter method is preferably used.

In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to the above-mentioned polyamic acid solution, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used as the dehydrating agent, for example. It is preferable that the usage-amount of a dehydrating agent is 0.01 mol - 20 mol with respect to 1 mol of amic-acid structures of a polyamic acid. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. The amount of the dehydration ring-closing catalyst used is preferably 0.01 mol to 10 mol with respect to 1 mol of the dehydrating agent used. Examples of the organic solvent used in the dehydration ring-closing reaction include those exemplified as the organic solvent used in the synthesis of polyamic acid. The reaction temperature of the dehydration ring-closing reaction is preferably 0°C to 180°C, more preferably 10°C to 150°C. The reaction time is preferably 1.0 hour to 120 hours, more preferably 2.0 hours to 30 hours.

In this way, the reaction solution containing polyimide was obtained. This reaction solution can be directly used for preparation of liquid crystal alignment agent, can also be used for preparation of liquid crystal alignment agent after removing dehydrating agent and dehydration ring-closing catalyst from the reaction solution, can also be used for liquid crystal alignment after isolating polyimide preparation of the liquid crystal alignment agent, or the isolated polyimide may be purified and supplied to the preparation of the liquid crystal alignment agent. These purification operations can be performed according to known methods.

<Solution Viscosity of Polymer>

The specific polymer obtained as described above preferably has a solution viscosity of 20 mPa·s to 800 mPa·s, more preferably a solution of 30 mPa·s to 500 mPa·s when it is made into a solution having a concentration of 10% by weight. viscosity.

The solution viscosity (mPa·s) of the above-mentioned polymer is a polymer solution prepared with a concentration of 10% by weight using a good solvent for the polymer (such as γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) , is a value measured at 25° C. using an E-type rotational viscometer.

In addition, the polyamic acid and polyimide preferably have a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 1,000 to 500,000, particularly preferably 2,000 to 300,000; and Mw The ratio (Mw/Mn) to the polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is preferably 15 or less, particularly preferably 10 or less. Favorable alignment and stability of a liquid crystal display element can be ensured by making it into such a molecular weight range.

<Other additives>

The liquid crystal alignment film of the present invention contains the above-mentioned specific polymer as an essential component, and may also contain other components as required. Examples of such other components include other polymers, compounds having at least one epoxy group in the molecule (hereinafter referred to as "epoxy compounds"), functional silane compounds, and the like.

[Other polymers]

The other polymers mentioned above can be used to improve solution properties and electrical properties. This other polymer is a polymer other than a specific polymer, for example, a polyamic acid obtained by reacting a tetracarboxylic dianhydride with a diamine, and the tetracarboxylic dianhydride does not contain a bicyclic [2.2.1] Heptane-2,3,5,6-tetracarboxylic dianhydride, or in the case of bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.1] The said heptane-2,3,5,6-tetracarboxylic dianhydride in which the isomer represented by the above formula (1) is less than 70 mol% (preferably 50 mol% or less, more preferably 0 mol%) Polyamic acids (hereinafter referred to as "other polyamic acids"), polyimides obtained by dehydrating and ring-closing the "other polyamic acids" (hereinafter referred to as "other polyimides"), polyamic acid esters, Polyester, polyamide, polysiloxane, cellulose derivatives, polyoxymethylene, polystyrene derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, etc. Among these compounds, at least one polymer selected from the group consisting of other polyamic acids and other polyimides is preferable.

Tetracarboxylic dianhydrides used to synthesize the above-mentioned other polyamic acids or other polyimides include the same tetracarboxylic dianhydrides described above as other tetracarboxylic dianhydrides preferably used for synthesizing specific polymers. Acid dianhydride, preferably selected from 1,2,3,4-cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride and 1,3, 3a, 4, 5, 9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3-dione At least one of the groups of .

As the diamine for synthesizing the other polyamic acid or other polyimide described above, it is preferable to use at least one kind of diamine selected from the diamines exemplified above as the diamine used when synthesizing the specific polymer. Diamines used to synthesize other polyamic acids or other polyimides are preferably selected from 4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminobiphenyl , cholestanyloxy-2,4-diaminobenzene, 3,5-diaminobenzoic acid, and at least one member of the group consisting of 1,4-bis-(4-aminophenyl)-piperazine .

The proportion of other polymers used is preferably 50% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less. When other polymers are used, the effect of the addition can be remarkably expressed if the usage ratio thereof is 0.1% by weight or more relative to the total amount of the polymers.

[epoxy compound]

In order to further improve the adhesion and heat resistance of the obtained liquid crystal alignment film to the substrate, etc., the liquid crystal alignment agent of the present invention may contain an epoxy compound.

The above-mentioned epoxy compound is preferably an epoxy compound having two or more epoxy groups in the molecule, and examples thereof include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and tripropylene glycol diglycidyl ether. Glyceryl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2 -Dibromoneopentyl glycol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl ) cyclohexane, N, N, N', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-di Glycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, etc. are preferred epoxy compounds.

As an epoxy compound, if its usage ratio is too small, the desired effect as described above cannot be fully exhibited; on the other hand, if its usage ratio is too large, the reworkability and friction resistance of the liquid crystal alignment film will be impaired. sex. From this point of view, the blending ratio of the epoxy compound is preferably 30 parts by weight or less, more preferably 0.1 to 15 parts by weight, and even more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the polymer in total. Parts by weight are particularly preferably 1 to 3 parts by weight.

[Functional silane compound]

The above-mentioned functional silane compounds include, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane Oxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane , N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazepine Decane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-trimethoxy Silyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, 9-trimethoxysilyl-3,6- Methyl diazanonanoate, 9-triethoxysilyl-3,6-methyl diazanonanoate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3 -aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, glycidyloxymethyltrimethoxy Silane, Glycidyloxymethyltriethoxysilane, 2-Glycidoxyethyltrimethoxysilane, 2-Glycidoxyethyltriethoxysilane, 3-Glycidoxypropyltrimethoxysilane Oxysilane, 3-glycidoxypropyltriethoxysilane, etc.

The usage ratio of these functional silane compounds is preferably 2 parts by weight or less, more preferably 0.02 to 0.2 parts by weight with respect to a total of 100 parts by weight of the polymer.

<Liquid crystal alignment agent>

It is preferable that the liquid crystal alignment agent of this invention melt|dissolves and contains the above-mentioned specific polymer and other additives mix|blended arbitrarily as needed in an organic solvent, and is comprised.

Examples of organic solvents used in the liquid crystal alignment agent of the present invention include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N- Dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, 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 cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate , Diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetic acid ester, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, etc. These organic solvents may be used alone or in combination of two or more.

The solid content concentration in the liquid crystal alignment agent of the present invention (the ratio of the total weight of the components in the liquid crystal alignment agent except the solvent to the total weight of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, etc., preferably It is the range of 1 weight% - 10 weight%. That is, the liquid crystal alignment agent of the present invention can be coated on the surface of the substrate as described later, preferably heated to form a coating film as a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film, but when the solid content concentration is less than 1 % by weight, the film thickness of the coating film becomes too small to obtain a good liquid crystal alignment film; on the other hand, if the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes too large to obtain a good The liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases, resulting in poor coating properties.

The range of the particularly preferable solid content concentration differs with the method used when coating a liquid crystal alignment agent on a board|substrate. For example, when using the spin coating method, the solid content concentration is particularly preferably in the range of 1.5% by weight to 4.5% by weight. In the case of using the printing method, it is particularly preferable to set the solid content concentration in a range of 3% by weight to 9% by weight so that the solution viscosity is in a range of 12mPa·s to 50mPa·s. In the case of using the inkjet method, it is particularly preferable to set the solid content concentration to be in the range of 1% by weight to 5% by weight, whereby the solution viscosity is to be in the range of 3mPa·s to 15mPa·s.

The temperature when preparing the liquid crystal alignment agent of the present invention is preferably 10°C to 50°C, more preferably 20°C to 30°C.

<Liquid crystal display element>

The liquid crystal display element of the present invention includes a liquid crystal alignment film formed from the above-mentioned liquid crystal alignment agent of the present invention. More specifically, the liquid crystal display element of the present invention is formed by disposing polarizing plates on the two outer surfaces of the liquid crystal cell, and is characterized in that: the liquid crystal cell has two substrates with liquid crystal alignment films and each liquid crystal alignment film surface The liquid crystal layer is sandwiched between the gaps arranged opposite to each other, and the liquid crystal alignment film is formed by the liquid crystal alignment agent of the present invention.

The liquid crystal display element of this invention can be manufactured by the process of following (1)-(3), for example. Step (1) uses different substrates depending on the desired mode of operation. Step (2) and step (3) are commonly used in each operation mode.

(1) 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) When manufacturing a TN-type, STN-type or VA-type liquid crystal display element, two substrates provided with a patterned transparent conductive film on one side are used as a pair, preferably by offset printing, rotary The liquid crystal alignment agent of the present invention is coated on each transparent conductive film forming surface by coating method or inkjet printing method, and then each coated surface is heated to form a coating film. Here, glass such as float glass and soda glass can be used as the substrate; polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly(alicyclic olefin) and other plastic transparent substrates. As the transparent conductive film provided on one side of the substrate, NESA film (registered trademark of PPG Corporation of the United States) containing tin oxide (SnO ₂ ), NESA film containing indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) can be used. ITO film etc., in order to obtain the patterned transparent conductive film, for example can utilize following method: after forming the transparent conductive film without pattern, utilize the method for forming pattern by photoetching; The method of masking, etc. When coating the liquid crystal alignment agent, in order to make the adhesion between the substrate surface and the transparent conductive film and the coating film better, it is also possible to pre-coat the surface of the substrate surface where the coating film needs to be formed. Functional silane compounds, functional Pretreatment of permanent titanium compounds, etc.

After applying the liquid crystal alignment agent, it is preferable to perform preheating (prebaking) in order to prevent the applied alignment agent from running and the like. The prebaking temperature is preferably 30°C to 200°C, more preferably 40°C to 150°C, particularly preferably 40°C to 100°C. The prebaking time is preferably 0.25 minutes to 10 minutes, preferably 0.5 minutes to 5 minutes. Thereafter, the solvent is completely removed, and a firing (post-baking) step is implemented for the purpose of thermally imidating the polyamic acid as needed. The calcination (post-baking) temperature is preferably 80°C to 300°C, more preferably 120 to 250°C. The post-baking time is preferably 5 minutes to 200 minutes, more preferably 10 minutes to 100 minutes. The film thickness of the film formed as described above is preferably 0.001 μm to 1 μm, more preferably 0.005 μm to 0.5 μm.

(1-2) On the other hand, in the case of manufacturing a liquid crystal display element of a transverse electric field mode, the liquid crystal alignment agent of the present invention is respectively coated on a pair of transparent conductive films patterned in a comb-shaped pattern on one side. The conductive film formation surface of the substrate and the single surface of the counter substrate on which the conductive film is not provided are then heated on each coated surface to form a coating film.

Regarding the materials of the substrate and transparent conductive film used at this time, the patterning method of the transparent conductive film, the pretreatment of the substrate, the coating method of the liquid crystal alignment agent, the heating method after coating the liquid crystal alignment agent, and the formed coating film The film thickness is the same as the above (1-1).

(2) When the liquid crystal display element manufactured by the method of the present invention is a VA-type liquid crystal display element, the coating film formed as described above can be directly used as a liquid crystal alignment film, and the following steps can also be carried out as needed. After the friction treatment described above, it is ready for use.

On the other hand, when producing liquid crystal display elements other than the VA type, a liquid crystal alignment film is produced by rubbing the coating film formed as described above.

The rubbing treatment can be performed by rubbing the surface of the coating film formed as described above in a fixed direction with a roller wound with a cloth containing fibers such as nylon, rayon, and cotton. Thereby, the alignment ability of a liquid crystal molecule is given to a coating film, and it becomes a liquid crystal alignment film.

In addition, the liquid crystal alignment film formed as above is subjected to, for example, a process of changing the pretilt angle of a part of the liquid crystal alignment film by irradiating a part of the liquid crystal alignment film with ultraviolet light (refer to Patent Document 10 (Japanese Patent Laid-Open No. 6-222366 No. Publication) and Patent Document 11 (Japanese Patent Laid-Open Publication No. 6-281937)); after forming a resist film on a part of the surface of the liquid crystal alignment film, perform rubbing treatment in a direction different from the previous rubbing treatment, and then remove The treatment of the resist film makes each region of the liquid crystal alignment film have a different liquid crystal alignment ability, thereby improving the viewing characteristics of the obtained liquid crystal display element (refer to Patent Document 12 (Japanese Patent Laid-Open Publication No. 5-107544)) Wait.

(3) Two substrates on which the liquid crystal alignment film was formed as described above were prepared, and a liquid crystal was arranged between the two substrates arranged to face each other to manufacture a liquid crystal cell. Here, when rubbing the coating film, two substrates are arranged facing each other so that the rubbing directions of the respective coating films are mutually at a predetermined angle, for example, perpendicular or antiparallel.

When manufacturing a liquid crystal cell, the following two methods are mentioned, for example.

The first method is a conventionally known method. First, two substrates are arranged facing each other with a gap (cell gap) interposed therebetween so that the respective liquid crystal alignment films face each other, and the peripheral parts of the two substrates are bonded together using a sealant, and the substrate surface and the sealant are separated. After filling the liquid crystal into the cell gap, the injection hole is sealed, so that the liquid crystal cell can be manufactured.

The second method is a technique called ODF (One Drop Fill, instillation method) method. Coat, for example, a UV-curable sealing material on a predetermined position on one of the two substrates on which the liquid crystal alignment film is formed, and further drop liquid crystals on several predetermined positions on the surface of the liquid crystal alignment film. The alignment film is attached to another substrate so that the liquid crystal is spread on the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light to harden the sealant, thereby manufacturing a liquid crystal cell.

In the case of using any method, it is desirable to further heat the liquid crystal cell manufactured as described above to the temperature at which the liquid crystal used becomes an isotropic phase, and then gradually cool it to room temperature, thereby removing the flow alignment.

Next, the liquid crystal display element of the present invention is obtained by bonding a polarizing plate to the outer surface of the liquid crystal cell.

Here, as the sealing agent, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used.

Said liquid crystal, for example, can use nematic liquid crystal, smectic liquid crystal, etc., among them, preferably nematic liquid crystal, for example, can use Schiff base liquid crystal, azo oxide liquid crystal, biphenyl liquid crystal, phenyl ring liquid crystal, etc. Hexane-based liquid crystals, ester-based liquid crystals, terphenyl-based liquid crystals, biphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals, cubane-based liquid crystals, etc. Furthermore, for example, the following compounds can be further added to these liquid crystals: cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonanoate, and cholesteryl carbonate; as trade names C-15, CB-15 (Merck & Co. company) and commercially available chiral agents; p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate and other ferroelectric liquid crystals.

As the polarizing plate attached to the outer surface of the liquid crystal cell, a polarizing film called "H film" is sandwiched between acetate protective films. A polarizing plate made of a polarizing film) or a polarizing plate including the H film itself.

[example]

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

The compounds represented by the above-mentioned formula (1) used in the following synthesis examples can be obtained according to those described in Non-Patent Document 1 (Journal of Organic Chemistry (J.Org.Chem.), 57, 6075-6077 (1992)). Method and the product that the isomer purity synthesized by the route of above-mentioned scheme 1 is 100%.

The solution viscosity of each polymer solution in a polymerization example, and the imidization ratio of a polyimide can be measured by the following method.

[Solution Viscosity of Polymer Solution]

In the solvent and concentration described in each synthesis example, the solution viscosity (mPa*s) of a polymer solution was measured at 25 degreeC using the E-type rotational viscometer.

[Imidation rate of polyimide]

Take a small amount of polyimide solution and put it into methanol, dry the obtained precipitate under reduced pressure at room temperature, dissolve it in deuterated dimethyl sulfoxide, and use tetramethylsilane as the standard substance to dissolve at room temperature Then measure ¹ H-NMR. From the obtained ¹ H-NMR spectrum, the imidation rate was calculated from the formula represented by the following mathematical formula (1):

Imidization rate (%)=(1-A ¹ /A ² ×α)×100(1)

In the mathematical formula (1), A ¹ is the peak area of the proton derived from the NH group appearing near the chemical shift 10ppm,

^A2 is the peak area derived from other protons,

α is the number ratio of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

<Synthesis of Polymers for TN Type Liquid Crystal Alignment Agent>

[Synthesis example of polyamic acid as specific polymer]

Synthesis Example A-TN1

118 g (0.50 mol) of the compound represented by the above formula (1) as tetracarboxylic dianhydride, 109 g (0.50 mol) of pyromellitic dianhydride, and 4,4'-diaminodiphenylmethane as diamine 198 g (1.0 mol) was dissolved in a mixed solvent containing 246 g of N-methyl-2-pyrrolidone and 2,213 g of γ-butyrolactone, and the reaction was carried out at room temperature for 20 hours while stirring with a mechanical stirrer, thereby obtaining 15% by weight solution of polyamic acid (A-TN1). The solution viscosity of this solution was 176 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

[Synthesis examples of other polyamic acids]

Synthesis example a-TN2

109 g (0.50 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 98 g (0.50 mol) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 4,4'- 198 g (1.0 mol) of diaminodiphenylmethane was dissolved in a mixed solvent containing 230 g of N-methyl-2-pyrrolidone and 2,068 g of γ-butyrolactone, and the mixture was stirred at 40°C for 3 hours with a mechanical stirrer. reaction, thereby obtaining a solution containing 15% by weight of polyamic acid (a-TN2). The solution viscosity of this solution was 193 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

[Synthesis example of polyimide as specific polymer]

Synthesis Example B-TN1

118 g (0.50 mol) of the compound represented by the above-mentioned formula (1) as tetracarboxylic dianhydride, 112 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride, and terephthalic diamine as diamine Dissolve 106 g (0.985 mol) of amine and 7.8 g (0.015 mol) of 3-(3,5-diaminobenzoyloxy)cholestane in 3,042 g of N-methyl-2-pyrrolidone while using a mechanical stirrer. It reacted at 60 degreeC for 6 hours, stirring, and obtained the solution containing a polyamic acid. The solution viscosity of the polyamic acid solution obtained here was 160 mPa·s.

To the obtained polyamic acid solution, 3,380 g of N-methyl-2-pyrrolidone was added, and a dehydration ring-closure reaction was performed at 110° C. for 4 hours while adding and stirring 395 g of pyridine and 306 g of acetic anhydride. After the dehydration ring-closing reaction, the solvent in the system is replaced with new γ-butyrolactone (by this operation, the pyridine and acetic anhydride used in the imidization reaction are removed to the outside of the system. The same below), and further By concentrating, a solution containing 10% by weight of a polyimide (B-TN1) having an imidation rate of about 94% was obtained.

A small amount of this solution was taken, and γ-butyrolactone was added to prepare a solution having a concentration of 6% by weight. The measured solution viscosity was 28 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

[Synthesis examples of other polyimides]

Synthesis example b-TN2

110 g (0.50 moles) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 1,3,3a,4,5,9b-hexahydro-8-methyl-5- (Tetrahydro-2,5-dioxo-3-furyl)naphtho[1,2-c]furan-1,3-dione 155g (0.50mol), p-phenylenediamine as diamine 92g ( 0.87 mol), 25 g (0.10 mol) of bisaminopropyl tetramethyldisiloxane and 13 g (0.02 mol) of 3,6-bis(4-aminobenzoyloxy) cholestane, and aniline as monoamine 2.7 g (0.030 mol) was dissolved in 960 g of N-methyl-2-pyrrolidone, and it reacted at 60 degreeC for 6 hours, stirring using the mechanical stirrer, and obtained the solution containing a polyamic acid. A small amount of the obtained polyamic acid solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyamic acid concentration of 10% by weight. The measured solution viscosity was 59 mPa·s.

Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 396 g of pyridine and 409 g of acetic anhydride were added, and dehydration ring closure was performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system was replaced with new γ-butyrolactone, and further concentrated to obtain about 2,520 g of a polymer containing 15% by weight and an imidization rate of about 95%. Solution of imide (b-TN2). A small amount of this polyimide solution was fractionated, and γ-butyrolactone was added to prepare a solution having a polyimide concentration of 6.0% by weight, and the solution viscosity measured was 18 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis example b-TN3

224 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 106 g (0.985 mol) of p-phenylenediamine as diamine and 3-(3,5-diamine 7.8 g (0.015 mol) of aminobenzoyloxy)cholestane was dissolved in 3,042 g of N-methyl-2-pyrrolidone, and the reaction was carried out at 60° C. for 6 hours while stirring with a mechanical stirrer to obtain a polymer containing Amic acid solution. The solution viscosity of the polyamic acid solution obtained here was 181 mPa·s.

To the obtained polyamic acid solution, 3,380 g of N-methyl-2-pyrrolidone was added, 395 g of pyridine and 306 g of acetic anhydride were added, and a dehydration ring-closure reaction was performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system is carried out solvent replacement with new gamma-butyrolactone, and further concentrates, thus obtains the polyimide ( b-TN3) solution.

A small amount of this solution was taken, and γ-butyrolactone was added to prepare a solution having a concentration of 6% by weight. The measured solution viscosity was 35 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

<Synthesis and Stability Evaluation of Polymers for VA Type Liquid Crystal Alignment Agents>

[Synthesis example of polyimide as specific polymer]

Synthesis Example B-VA1

118 g (0.50 mol) of the compound represented by the above-mentioned formula (1) as tetracarboxylic dianhydride, 112 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride, and 3,5 -Diaminobenzoic acid cholestanyl 52g (0.1 mole), cholestanyloxy-2,4-diaminobenzene 49g (0.1 mole) and p-phenylenediamine 87g (0.80 mole) are dissolved in N-methyl - In 1,652 g of 2-pyrrolidone, it reacted at 60 degreeC for 6 hours, stirring using the mechanical stirrer, and obtained the polyamic-acid solution. A small amount of the obtained polyamic acid solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight. The solution viscosity measured was 79 mPa·s.

Next, 3,835 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 79 g of pyridine and 102 g of acetic anhydride were added, and dehydration ring closure was performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system is replaced with new N-methyl-2-pyrrolidone to obtain a polyimide (B- VA1) solution. A small amount of the obtained polyimide solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyimide concentration of 10% by weight, and the measured solution viscosity was 102 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis Example B-VA2

47 g (0.20 mol) of the compound represented by the above formula (1) as tetracarboxylic dianhydride, 180 g (0.80 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride, and 3,5 - 105 g (0.20 mol) of cholestyl diaminobenzoate and 87 g (0.80 mol) of p-phenylenediamine were dissolved in 1,663 g of N-methyl-2-pyrrolidone, and stirred with a mechanical stirrer at 60°C The reaction was performed for 6 hours to obtain a polyamic acid solution. A small amount of the obtained polyamic acid solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight. The solution viscosity measured was 59 mPa·s.

Next, 3,861 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 79 g of pyridine and 102 g of acetic anhydride were added, and dehydration ring closure was performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system is replaced with new N-methyl-2-pyrrolidone, thereby obtaining a polyimide ( B-VA2) solution. A small amount of the obtained polyimide solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyimide concentration of 10% by weight, and the measured solution viscosity was 80 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis Example B-VA3

141 g (0.60 mol) of the compound represented by the above formula (1) as tetracarboxylic dianhydride, 90 g (0.40 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride, and 3,5 - 105g (0.20 mole) of cholestanyl diaminobenzoate, 65g (0.60 mole) of p-phenylenediamine and 30g (0.20 mole) of 3,5-diaminobenzoic acid were dissolved in 1,697 g of N-methyl-2-pyrrolidone In g, reaction was performed at 60° C. for 6 hours while stirring using a mechanical stirrer, and a polyamic acid solution was obtained. A small amount of the obtained polyamic acid solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight. The solution viscosity measured was 50 mPa·s.

Next, 3,939 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 119 g of pyridine and 153 g of acetic anhydride were added, and dehydration and ring closure were performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system is carried out solvent replacement with new N-methyl-2-pyrrolidone, thereby obtaining polyimide ( B-VA3) solution. A small amount of the obtained polyimide solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyimide concentration of 10% by weight. The solution viscosity measured was 79 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

[Synthesis examples of other polyimides]

Synthesis example b-VA4

224 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 52 g (0.10 mol) of cholestyl 3,5-diaminobenzoate as diamine , 49 g (0.10 moles) of cholestanyloxy-2,4-diaminobenzene and 87 g (0.80 moles) of p-phenylenediamine were dissolved in 1,652 g of N-methyl-2-pyrrolidone, while stirring with a mechanical stirrer The reaction was performed at 60° C. for 6 hours to obtain a polyamic acid solution. A small amount of the obtained polyamic acid solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight. The solution viscosity measured was 70 mPa·s.

Next, 3,835 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 79 g of pyridine and 102 g of acetic anhydride were added, and dehydration ring closure was performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system is carried out solvent replacement with new N-methyl-2-pyrrolidone, thereby obtaining polyimide ( b-VA4) solution. A small amount of the obtained polyimide solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyimide concentration of 10% by weight, and the measured solution viscosity was 80 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis example b-VA5

224 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 105 g (0.20 mol) of 3,5-diaminobenzoic acid cholestyl group as diamine, 65 g (0.60 mol) of p-phenylenediamine and 30 g (0.20 mol) of 3,5-diaminobenzoic acid were dissolved in 1,697 g of N-methyl-2-pyrrolidone, and the 6- Hours of reaction to obtain a polyamic acid solution. A small amount of the obtained polyamic acid solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight. The solution viscosity measured was 50 mPa·s.

Next, 3,939 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 119 g of pyridine and 153 g of acetic anhydride were added, and dehydration and ring closure were performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system is replaced with new N-methyl-2-pyrrolidone, thereby obtaining polyimide ( b-A solution of VA5). A small amount of the obtained polyimide solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyimide concentration of 10% by weight, and the measured solution viscosity was 73 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

<Synthesis of Polymer for IPS Type Liquid Crystal Alignment Agent>

[Synthesis example of polyamic acid as specific polymer]

Synthesis Example A-IPS1

Dissolve 47 g (0.20 mol) of the compound represented by the above formula (1) as tetracarboxylic dianhydride, 174 g (0.80 mol) of pyromellitic dianhydride, and 108 g (1.0 mol) of p-phenylenediamine as diamine in In 1,900 g of N-methyl-2-pyrrolidone, it reacted at room temperature for 20 hours, stirring using the mechanical stirrer, and obtained the solution containing the polyamic acid (A-IPS1) of 15 weight%.

A small amount of this solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyamic acid concentration of 10% by weight. The measured solution viscosity was 75 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis Example A-IPS2

189 g (0.80 mol) of the compound represented by the above formula (1) as tetracarboxylic dianhydride, 44 g (0.20 mol) of pyromellitic dianhydride, and 4,4'-diaminodiphenyl ether as diamine 160 g (0.80 mol) and 110 g (0.20 mol) of p-phenylenediamine were dissolved in 2,300 g of N-methyl-2-pyrrolidone, and the reaction was carried out at room temperature for 20 hours while stirring with a mechanical stirrer, thereby obtaining 15 A solution of polyamic acid (A-IPS2) in % by weight.

A small amount of this solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyamic acid concentration of 10% by weight. The measured solution viscosity was 74 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis Example A-IPS3

189 g (0.80 mol) of the compound represented by the above formula (1) as tetracarboxylic dianhydride, 44 g (0.20 mol) of pyromellitic dianhydride, and 4,4'-diaminodiphenylamine as diamine 200g (1.0 mole) was dissolved in N-methyl-2-pyrrolidone 2,400g, while using a mechanical stirrer to stir, carry out reaction at room temperature for 20 hours, thus obtaining polyamic acid (A-IPS3) containing 15% by weight )The solution.

A small amount of this solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyamic acid concentration of 10% by weight. The measured solution viscosity was 65 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

[Synthesis examples of other polyamic acids]

Synthesis example a-IPS4

Dissolve 220 g (1.0 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 110 g (1.0 mol) of p-phenylenediamine as diamine in 1,800 g of N-methyl-2-pyrrolidone. The reaction was performed at 40° C. for 3 hours while stirring with a stirrer, thereby obtaining a solution containing 15% by weight of polyamic acid (a-IPS4).

The solution viscosity of this solution was 180 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis example a-IPS5

220 g (1.0 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride, 160 g (0.80 mol) of 4,4′-diaminodiphenyl ether as diamine and 22 g (0.20 mol) of p-phenylenediamine It was dissolved in 2,300 g of N-methyl-2-pyrrolidone and reacted at 40° C. for 3 hours while stirring using a mechanical stirrer to obtain a solution containing 15% by weight of polyamic acid (a-IPS5).

A small amount of this solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyamic acid concentration of 10% by weight. The measured solution viscosity was 71 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis example a-IPS6

200 g (0.90 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 20 g (0.10 mol) of 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 4,4'- 160 g (0.80 mol) of diaminodiphenyl ether and 22 g (0.20 mol) of p-phenylenediamine were dissolved in 2,300 g of N-methyl-2-pyrrolidone, and the mixture was stirred at 40° C. for 3 hours while stirring with a mechanical stirrer. reaction, thereby obtaining a solution containing 15% by weight of polyamic acid (a-IPS6).

A small amount of this solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyamic acid concentration of 10% by weight. The measured solution viscosity was 77 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

[Synthesis example of polyimide as specific polymer]

Synthesis Example B-IPS1

118 g (0.50 mol) of the compound represented by the above-mentioned formula (1) as tetracarboxylic dianhydride, 112 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride, and terephthalic diamine as diamine Amine 86g (0.80 mol), 4,4'-diaminodiphenylmethane 23g (0.10 mol) and 4,4'-bis(trifluoromethyl)biphenyl 32g (0.10 mol) were dissolved in N-methyl- In 2,100g of 2-pyrrolidone, it reacted at room temperature for 20 hours, stirring using the mechanical stirrer, and obtained the polyamic-acid solution. A small amount of the obtained polyamic acid solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight. The solution viscosity measured was 40 mPa·s.

Next, 2,800 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 g of acetic anhydride were added, and a dehydration ring-closure reaction was performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system is replaced with gamma-butyrolactone, followed by concentration, thus obtaining a polyimide (B- IPS1) solution 2,300 g. A small amount of this solution was fractionated, and γ-butyrolactone was added to prepare a solution having a polyimide concentration of 10% by weight. The measured viscosity was 36 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis Example B-IPS2

118 g (0.50 mol) of the compound represented by the above-mentioned formula (1) as tetracarboxylic dianhydride, 112 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride, and terephthalic diamine as diamine 97 g (0.90 mol) of amine and 32 g (0.10 mol) of 4,4′-bis(trifluoromethyl)biphenyl were dissolved in 2,000 g of N-methyl-2-pyrrolidone, and stirred with a mechanical stirrer at room temperature The reaction was carried out for 20 hours to obtain a polyamic acid solution. A small amount of the obtained polyamic acid solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight, and the measured solution viscosity was 46 mPa·s.

Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 400 g of pyridine and 310 g of acetic anhydride were added, and a dehydration ring-closure reaction was performed at 110° C. for 4 hours while stirring. After the dehydration ring-closing reaction, the solvent in the system is replaced with gamma-butyrolactone, followed by concentration, thereby obtaining a polyimide (B- IPS2) solution 2,300 g. A small amount of this solution was fractionated, and γ-butyrolactone was added to prepare a solution having a polyimide concentration of 10% by weight. The measured solution viscosity was 42 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

[Synthesis examples of other polyimides]

Synthesis example b-IPS3

Except having used 220 g (1.0 mol) of 2, 3, 5- tricarboxycyclopentyl acetic acid dianhydrides as tetracarboxylic dianhydride, it carried out similarly to synthesis example B-IPS1, and obtained the polyamic-acid solution. A small amount of this solution was taken, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight. The measured solution viscosity was 48 mPa·s.

Next, after the dehydration ring-closing reaction was carried out in the same manner as in Synthesis Example B-IPS1, the solvent in the system was replaced with γ-butyrolactone, and then concentrated to obtain an imidization rate of about 15% by weight. 2,300 g of a solution of 93% polyimide (b-IPS3). A small amount of this solution was fractionated, and γ-butyrolactone was added to prepare a solution having a polyimide concentration of 10% by weight, and the measured viscosity was 45 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

Synthesis example b-IPS4

Except having used 220 g (1.0 mol) of 2,3,5- tricarboxy cyclopentyl acetic acid dianhydrides as tetracarboxylic dianhydride, it carried out similarly to synthesis example B-IPS4, and obtained the polyamic-acid solution. A small amount of this solution was taken, and N-methyl-2-pyrrolidone was added to prepare a solution having a polymer concentration of 10% by weight. The measured solution viscosity was 45 mPa·s.

Next, after the dehydration ring-closing reaction was carried out in the same manner as in Synthesis Example B-IPS4, the solvent in the system was replaced with γ-butyrolactone, and then concentrated to obtain an imidization rate of about 15% by weight. 93% solution of polyimide (b-IPS4) 2,300g. A small amount of this solution was fractionated, and γ-butyrolactone was added to prepare a solution having a polyimide concentration of 10% by weight, and the measured viscosity was 41 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, it did not gel and had good storage stability.

<Reference synthesis example>

Synthesis Example A-IPS5

Dissolve 224 g (1.0 mol) of 1S, 2S, 4R, 5R-cyclohexanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 108 g (1.0 mol) of p-phenylenediamine as diamine in N-methyl-2 -In 1,900 g of pyrrolidone, stirring using a mechanical stirrer, it reacted at 40 degreeC for 3 hours, and obtained the solution containing the polyamic acid of 15 weight%.

A small amount of this solution was fractionated, and N-methyl-2-pyrrolidone was added to prepare a solution having a polyamic acid concentration of 10% by weight. The measured solution viscosity was 99 mPa·s.

When the polymer solution was left to stand at 20° C. for 3 days, gelation was observed and the storage stability was poor.

<Preparation and evaluation of TN type liquid crystal alignment agent>

Example TN-1

(I) Preparation of liquid crystal alignment agent

The solution containing polyamic acid (A-TN1) obtained in the above synthesis example A-TN1 as a specific polymer in an amount equivalent to 80 parts by weight in terms of polyamic acid (A-TN1) and the conversion of In terms of polyimide (b-TN2), the solution containing polyimide (b-TN2) obtained in the above-mentioned synthesis example b-TN2 as other polymers in an amount corresponding to 20 parts by weight was combined, and the Add N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (BL) and butyl cellosolve (BC) to make the final solvent composition NMP:BL:BC=17:71:12 (weight ratio) , 2 parts by weight of N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane was further added as an epoxy compound to prepare a solution having a solid content concentration of 3.5% by weight. After stirring this solution well, it filtered using the filter whose pore diameter was 1 micrometer, and prepared the liquid crystal alignment agent.

(II) Evaluation of liquid crystal alignment agent

(1) Manufacture of TN-type liquid crystal cell

Using a liquid crystal alignment film printer (manufactured by Nippon Photo Printing Co., Ltd.), the liquid crystal alignment agent prepared above was coated on the transparent electrode surface of a glass substrate with a transparent electrode comprising an ITO film, and carried out on a hot plate at 80°C for 1 After heating (pre-baking) for 10 minutes to remove the solvent, heat (post-baking) for 10 minutes on a hot plate at 200°C to form an average film thickness of coating film.

Using a rubbing machine with a roller wound with rayon cloth, the coating film was subjected to rubbing treatment at a roller rotation speed of 500 rpm, a table moving speed of 3 cm/sec, and a bristle indentation length of 0.4 mm to impart liquid crystal alignment capability. Thereafter, ultrasonic cleaning was performed in ultrapure water for 1 minute, followed by drying in a clean oven at 100° C. for 10 minutes, whereby a substrate having a liquid crystal alignment film was obtained. This operation was repeated to obtain a pair (two sheets) of substrates having a liquid crystal alignment film.

Next, on the outer edge of the surface with the liquid crystal alignment film of one of the above-mentioned pair of substrates, apply an epoxy resin adhesive with a diameter of 5.5 μm alumina balls, so that the pair of substrates are coated with the liquid crystal alignment film. After facing each other and bonding them by pressure, the adhesive is hardened. Next, a nematic liquid crystal (MLC-6221, manufactured by Merck & Co., Ltd.) was filled between the pair of substrates from the liquid crystal injection port, and the liquid crystal injection port was sealed with an acrylic photocurable adhesive to manufacture a liquid crystal cell.

(2) Evaluation of heat resistance stability

The durability against thermal stress was evaluated using the voltage retention rate as an index. The measuring device of the voltage holding ratio used the model "VHR-1" manufactured by Toyo Techno Co., Ltd.

For the liquid crystal cell manufactured above, at 60° C., after applying a voltage of 5 V to the liquid crystal display element with an application time of 60 microseconds and a span of 167 milliseconds, the voltage retention rate (initial Voltage retention rate VHR0).

Next, for the liquid crystal display element after measuring the voltage holding ratio before applying the thermal stress, after standing still in an oven at 100° C. for 1,000 hours to apply the thermal stress, the voltage holding ratio was measured again in the same manner as above (the voltage holding ratio after the thermal stress was applied). rate VHR1).

Using the above-measured values of VHR0 and VHR1 , the difference ΔVHR in voltage retention before and after application of thermal stress was obtained by the following formula (2).

ΔVHR=VHR0-VHR1(2)

When the value is within 5%, it can be evaluated that the heat resistance stability is good.

The evaluation results are shown in Table 1.

Example TN-2 and Example TN-3 and Comparative Example tn-1 and Comparative Example tn-2

In the above example TN-1, solutions containing polymers of the types and amounts listed in Table 1 were used as specific polymers and other polymers, respectively, and added so that the final solvent composition became as described in Table 1. Except for each solvent, it carried out similarly to Example TN-1, prepared the liquid crystal aligning agent, and evaluated.

The evaluation results are shown in Table 1.

"-" in Table 1 indicates that the polymer corresponding to the column was not used. In Comparative Example tn-1, two types of polymers were mixed and used as other polymers.

The abbreviations of the solvents in Table 1 have the following meanings, respectively.

NMP: N-methyl-2-pyrrolidone

BL: γ-butyrolactone

BC: Butyl cellosolve

<Preparation and Evaluation of VA Type Liquid Crystal Alignment Agent>

Example VA-1

(I) Preparation of liquid crystal alignment agent

N-methyl-2-pyrrolidone and butyl cellosolve were added to the solution containing polyimide (B-VA1) obtained in the above-mentioned Synthesis Example B-VA1 as a polymer, and further adjusted with respect to the polyimide used. In terms of 100 parts by weight of imine, the amount of 5 parts by weight is added as N, N, N', N'-tetraglycidyl-m-xylylenediamine as an epoxy compound, and fully stirred to make a solvent composition of N - Methyl-2-pyrrolidone: butyl cellosolve = 50:50 (weight ratio), a solution with a solid content concentration of 3.5% by weight. This solution was filtered using a filter with a pore diameter of 1 μm to prepare a liquid crystal alignment agent.

(II) Evaluation of liquid crystal alignment agent

(1) Manufacture of VA liquid crystal cell

On the transparent conductive film including the ITO film set on one side of the glass substrate with a thickness of 1 mm, the liquid crystal alignment agent prepared above is coated with a spinner, and prebaked on a hot plate at 80 ° C for 1 minute , Next, post-baking was performed on a hot plate at 210° C. for 30 minutes to form a coating film (liquid crystal alignment film) having a film thickness of 80 nm. This operation was repeated to obtain two substrates (one pair) having a liquid crystal alignment film.

Next, on the outer edge of the surface with the liquid crystal alignment film of one of the above-mentioned pair of substrates, apply an epoxy resin adhesive with alumina balls with a diameter of 3.5 μm, so that the liquid crystal alignment films face each other. A pair of substrates are pressed against each other, and then the adhesive is cured. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was filled between the substrates from the liquid crystal injection port, and the liquid crystal injection port was sealed with an acrylic photocurable adhesive to manufacture a liquid crystal cell.

(2) Evaluation of heat resistance stability

Using the liquid crystal cell manufactured above, the evaluation of heat resistance stability was performed similarly to the said Example TN-1. Among them, in the case of the VA liquid crystal cell, when the value of the difference ΔVHR in the voltage holding ratio before and after the application of thermal stress is within 2%, it can be evaluated that the heat resistance stability is good.

The evaluation results are shown in Table 2.

Example VA-2 and Example VA-3 and Comparative Example VA-1 and Comparative Example VA-2

In said Example VA-1, except having used the solution containing the polymer described in Table 2 as a polymer, it carried out similarly to Example VA-1, prepared the liquid crystal alignment agent, and evaluated.

The evaluation results are shown in Table 2.

<Preparation and Evaluation of IPS Type Liquid Crystal Alignment Agent>

Example IPS-1

(I) Preparation of liquid crystal alignment agent

In the solution containing the polyamic acid (A-IPS1) obtained in the above synthesis example A-IPS1 as a polymer, add N-methyl-2-pyrrolidone and butyl cellosolve as a solvent, and further add relative to the used 100 parts by weight of the polyamic acid is 5 parts by weight of N, N, N', N'-tetraglycidyl-m-xylylenediamine as an epoxy compound and fully stirred to make a solvent composition of N -Methyl-2-pyrrolidone:butyl cellosolve=80:20 (weight ratio), a solution with a solid content concentration of 3.5% by weight. This solution was filtered using a filter with a pore diameter of 1 μm to prepare a liquid crystal alignment agent.

(II) Evaluation of liquid crystal alignment agent

(1) Manufacture of liquid crystal cell

Except having used the liquid crystal alignment agent prepared above, it carried out similarly to Example TN-1, the liquid crystal cell was manufactured, and the evaluation of heat resistance stability was performed.

The evaluation results are shown in Table 3.

In addition, the liquid crystal cell produced here is a TN type liquid crystal cell, and the present inventors confirmed empirically that a TN type liquid crystal cell can be used instead as a sample for heat resistance stability evaluation of an IPS type liquid crystal cell.

Example IPS-2 and Example IPS-3 and Comparative Example ips-1～Comparative Example ips-3

In said Example IPS-1, except having used the solution containing the polymer described in Table 3 as a polymer, it carried out similarly to Example IPS-1, prepared the liquid crystal alignment agent, and evaluated.

The evaluation results are shown in Table 3.

Example IPS-4 and Example IPS-5 and Comparative Example ips-4 and Comparative Example ips-5

In the above example IPS-1, the solutions containing the polymers listed in Table 3 were used as polymers, and N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (BL) and butyl cellosolve were used respectively. (BC) As a solvent, these solvents were added so that the final solvent composition became NMP:BL:BC=10:70:20 (weight ratio), and liquid crystal alignment was prepared in the same manner as Example IPS-1. agent is evaluated.

The evaluation results are shown in Table 3.

"-" in Table 3 indicates that the polymer corresponding to the column was not used.

The abbreviations of the solvents in Table 3 are the same as in Table 1.

Claims (5)

1. A liquid crystal alignment agent, which contains a group selected from polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine and polyimide obtained by dehydrating and ring-closing the polyamic acid. The group of liquid crystal alignment agents of at least one polymer, characterized in that: The tetracarboxylic dianhydride comprises bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, and the bicyclo[2.2.1]heptane-2,3,5,6-tetra The presence ratio of the isomer represented by the following formula (1) in formic acid dianhydride is 70 mol% or more, the weight average molecular weight of the polymer is 1,000-500,000, and the solid content concentration in the liquid crystal alignment agent is 1 % by weight to 10% by weight, the ratio of the weight average molecular weight of the polymer to the number average molecular weight is 15 or less, 2. The liquid crystal alignment agent according to claim 1, characterized in that: said diamine comprises p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl ) biphenyl, 4,4'-diaminodiphenylamine, and 4,4'-(m-phenylenediisopropylidene)diphenylamine at least one of the group consisting of. 3. The liquid crystal alignment agent according to claim 1, characterized in that it further contains a compound having at least one epoxy group in the molecule. 4. A liquid crystal alignment film, characterized in that it is formed by using the liquid crystal alignment agent according to any one of claims 1 to 3. 5. A liquid crystal display element, characterized by comprising the liquid crystal alignment film according to claim 4.