JP6120072B2 - Liquid crystal alignment agent - Google Patents

Description

The present invention relates to a liquid crystal aligning agent.
Specifically, the present invention relates to a liquid crystal aligning agent that provides a liquid crystal aligning film having excellent liquid crystal alignment properties, transparency, and rubbing resistance.

The liquid crystal display element performs display by an optical switching function that modulates light by enclosing liquid crystal between a pair of substrates arranged opposite to each other and changing the alignment of the liquid crystal by ON / OFF of voltage application.
Among liquid crystal display elements, horizontal alignment type liquid crystal displays such as twisted nematic liquid crystal display elements (TN mode), super twisted nematic liquid crystal display elements (STN mode), horizontal electric field display type liquid crystal display elements (IPS mode, FFS mode), etc. In the element, a horizontal alignment technique for aligning the liquid crystal in parallel with the substrate surface is required. In these modes, the function of aligning the liquid crystal is controlled by a rubbing-treated organic film (liquid crystal alignment film). The rubbing process is a process in which the organic film on the substrate is rubbed with a cloth having a long bristle, such as rayon or cotton, and the liquid crystal alignment ability in the direction rubbed with the cloth is imparted to the organic film to form a liquid crystal alignment film.
This rubbing treatment may cause scratches, exfoliation, and the like in the liquid crystal alignment film, sometimes resulting in display defects. For this reason, liquid crystal alignment film materials having excellent rubbing resistance have been demanded for a long time, various proposals have been made, and certain results have been achieved (Patent Documents 1 and 2).
However, in recent years, due to high definition of liquid crystal display elements, the size of one pixel has become smaller than before, and therefore the number of steps due to electronic components on the substrate on which the liquid crystal alignment film is formed has increased. . For this reason, recent liquid crystal alignment films are subjected to higher stress than before due to the rubbing treatment, so that scratches, exfoliation and the like are likely to occur. In addition to this, since the demand for higher definition of the liquid crystal display element does not allow display defects of fine sizes, the demand for the rubbing resistance of the liquid crystal alignment film is very severe. .
A liquid crystal alignment film material that sufficiently exhibits the liquid crystal alignment properties and transparency that are naturally required as a liquid crystal alignment film and satisfies the gist of the above severe rubbing resistance has not been known.

International Patent Publication No. 2011/068127 International Patent Publication No. 2004/053583 International Patent Publication No. 2010/053128 JP 2010-97188 A

The present invention meets the above requirements.
The objective of this invention is providing the liquid crystal aligning agent which provides the liquid crystal aligning film which is excellent in all the liquid crystal aligning property, transparency, and rubbing resistance.

The above objects and advantages of the present invention are as follows:
Liquid crystal alignment characterized by containing at least one polymer selected from the group consisting of a polyamic acid having a divalent group represented by the following formula (1) and an imidized polymer of the polyamic acid Achieved by the agent.

(In the formula (1), n1 is an integer of 1 to 3;
A plurality of X are each independently an oxygen atom or a sulfur atom;
A plurality of Y are each independently —NH— or an oxygen atom;
Two R ^{1 s} are each independently a single bond, a methylene group or an alkylene group having 2 to 6 carbon atoms;
R ² is each independently a divalent organic group when there are a plurality of R ² ;
“*” Represents a bond. )

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in liquid crystal aligning property and transparency, the liquid crystal aligning agent which provides the liquid crystal aligning film which can endure the severe severe rubbing process is provided. The liquid crystal alignment film formed from the liquid crystal aligning agent of this invention is suitable for a high-definition horizontal alignment type liquid crystal display element.

  As described above, the liquid crystal aligning agent of the present invention includes at least one heavy selected from the group consisting of a polyamic acid having a divalent group represented by the above formula (1) and an imidized polymer of the polyamic acid. A polymer (hereinafter referred to as “specific polymer”).

<Specific polymer>
The specific polymer contained in the liquid crystal aligning agent of the present invention has a divalent group represented by the above formula (1).
The formula (1) there are two R ¹ in the easiness of synthesis, it is preferably the same group to one another. R ¹ is preferably a single bond, a methylene group or an alkylene group having 2 to 4 carbon atoms, more preferably a single bond, a methylene group or a 1,2-ethylene group.
R ² in the above formula (1) is preferably a hydrocarbon group having 1 to 30 carbon atoms or a halogenated hydrocarbon group, more preferably, for example, a 1,2-ethylene group, 1,6-hexene. Xylene group, following formula

(In the above formula, “+” represents a bond, respectively.)
Group represented by each of the above.
The bond indicated by “*” in the formula (1) is preferably in the meta position or the para position with respect to other groups.
N1 in the above formula (1) is preferably 1.
Examples of groups represented by the above formula (1) include, for example, the following formulas (1-1-1) to (1-1-5), (1-2-1) to (1-2-5), (1-3-1) to (1-3-5), (1-4-1) to (1-4-5), (1-5-1) to (1-5-5), (1 -6-1) to (1-6-7) and (1-7-1) to (1-7-3)

(In the above formula, “*” indicates a bond, respectively.)
And groups represented by each of the above.
In the above formula (1), X is preferably an oxygen atom, and Y is preferably —NH—.
The specific polymer contained in the liquid crystal aligning agent of the present invention is one selected from the group consisting of a polyamic acid having a divalent group represented by the above formula (1) and an imidized polymer of the polyamic acid. As long as it is the above polymer, it may be synthesized by any method.
The specific polymer is
A tetracarboxylic dianhydride having a divalent group represented by the above formula (1) or a mixture of the tetracarboxylic dianhydride and other tetracarboxylic dianhydrides is reacted with a diamine. The resulting polyamic acid;
An imidized polymer of the polyamic acid;
Reaction of tetracarboxylic dianhydride with a diamine having a divalent group represented by the above formula (1) (hereinafter referred to as “specific diamine”), or a mixture of a specific diamine and other diamines. Preferably, the resulting polyamic acid; and at least one selected from the group consisting of imidized polymers of the polyamic acid:
A polyamic acid obtained by reacting a tetracarboxylic dianhydride with a specific diamine or a mixture of a specific diamine and another diamine; and at least one selected from the group consisting of imidized polymers of the polyamic acid It is more preferable that

[Tetracarboxylic dianhydride]
The tetracarboxylic dianhydride used for synthesizing the polyamic acid which is the specific polymer in the present invention includes aromatic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, and alicyclic tetracarboxylic acid. And dianhydrides.
The aromatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride formed by bonding two acid anhydride groups to an aromatic ring.
The aliphatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride in which two acid anhydride groups are bonded to a non-aromatic and acyclic hydrocarbon group, respectively. Here, it is only necessary that both of the bonding hands of the two acid anhydride groups are bonded to an acyclic and non-aromatic hydrocarbon group, and an alicyclic structure or It may have an aromatic structure or both of them.
The alicyclic tetracarboxylic dianhydride is a tetracarboxylic dianhydride formed by bonding at least one of a total of four bonds of two acid anhydride groups to an alicyclic hydrocarbon group. Say. It is preferable that any of the two bonds of one of the two acid anhydride groups is bonded to the alicyclic hydrocarbon group. In this case, the other acid anhydride group is preferably bonded to a non-aromatic and acyclic hydrocarbon group or bonded to an alicyclic hydrocarbon group. The alicyclic tetracarboxylic dianhydride may have an aromatic structure in a portion other than the hydrocarbon group to which the acid anhydride group is bonded.
In the above, the acid anhydride group means the following formula

(In the above formula, “*” represents a bond.)
A divalent group having a structure represented by:
Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, biphenyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, 4,4′-oxydiphthalate. In addition to acid anhydrides, aromatic tetracarboxylic dianhydrides described in Patent Document 4 (Japanese Patent Laid-Open No. 2010-97188) can be used, and one kind selected from these It is preferable to use the above. Among these, as the aromatic tetracarboxylic dianhydride, among these, pyromellitic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, and 4,4′-oxydiphthalic anhydride It is preferable to use one or more selected from the above, and it is more preferable to use pyromellitic dianhydride in that the liquid crystal alignment property of the liquid crystal alignment film to be formed can be improved.

Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride. Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a, 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5 9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 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-dicarbo Acid anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, bicyclo [3,3,0] octane-2,4,6,8-tetra Carboxylic dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, 1,2,4,5-cyclohexanetetracarboxylic acid In addition to dianhydrides, the alicyclic tetracarboxylic dianhydrides described in Patent Document 4 (Japanese Patent Laid-Open No. 2010-97188) can be used. It is preferable to use more than one species.

  Examples of the aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 2,3,5-tricarboxycyclopentyl among the above. Acetic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione 1,3,3a, 4,5,9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione , Bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride and 1,2,3,4-butanetetracarboxylic dianhydride From the group It is preferable to use at least one selected from the group consisting of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, (1S, 2S, 4R, 5R) -cyclohexanetetracarboxylic dianhydride, (1R, It is more preferable to use one or more selected from the group consisting of 2S, 4S, 5R) -cyclohexanetetracarboxylic dianhydride and 2,3,5-tricarboxycyclopentylacetic acid dianhydride. It is preferred to use 3,3,4-cyclobutanetetracarboxylic dianhydride.

By using at least one selected from the group consisting of an aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride, the voltage holding ratio of the liquid crystal display device to be obtained can be increased. In particular, when tetracarboxylic dianhydride used for synthesizing polyamic acid is only selected from the group consisting of aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride Thus, the effect of improving the voltage holding ratio is maximized.
As the tetracarboxylic dianhydride used for synthesizing the polyamic acid, only one selected from the group consisting of aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride is used, Alternatively, one or more selected from the group consisting of aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides and one or more selected from aromatic tetracarboxylic dianhydrides are used in combination. It is preferable to do.

In the tetracarboxylic dianhydride used for synthesizing the polyamic acid, the use ratio of one or more selected from the group consisting of an aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride is From the viewpoint of achieving both the rubbing resistance of the liquid crystal alignment film to be formed and the high voltage holding ratio in the obtained liquid crystal display element, it is preferably 10 mol% or more, more preferably 30 mol% or more, It is more preferable to set it as 50 mol% or more, and it is preferable to set it as 60 mol% or more especially.
When using an aromatic tetracarboxylic dianhydride together with one or more selected from the group consisting of an aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride as a tetracarboxylic dianhydride, The use ratio is preferably 5 to 50 mol%, more preferably 10 to 45 mol%, particularly from the viewpoint of achieving both liquid crystal orientation and high voltage holding ratio in the obtained liquid crystal display element. It is preferable to set it as 20-40 mol%.

[Diamine]
The diamine used for synthesizing the polyamic acid which is the specific polymer in the present invention contains the specific diamine.
The specific diamine is a diamine having a divalent group represented by the above formula (1), for example, the following formula (2)

(In the formula (2), n1, X, Y, R ¹ and R ² have the same meanings as in the formula (1)).
The compound represented by these can be mentioned. Specific diamines include the above formulas (1-1-1) to (1-1-5), (1-2-1) to (1-2-5), (1-3-1) to (1- 3-5), (1-4-1) to (1-4-5), (1-5-1) to (1-5-5), (1-6-1) to (1-6) 7) and a divalent group represented by each of (1-7-1) to (1-7-3), wherein an amino group is bonded to each of two bonds represented by “*”. It is preferable to use 1 or more types selected from the compound which becomes. Each of the two amino groups is preferably in the 4-position relative to the other groups on the benzene ring.
The specific diamine can be synthesized by appropriately combining organic chemistry methods. For example, in the above formula (2), a compound in which n1 is 1, X is an oxygen atom, and all of Y is —NH— is, for example, the formula OCN—R ² —NCO (where R ² is the above 1 equivalent of diisocyanate represented by the formula (2) and the following formula:

(In the above formula, R ¹ has the same meaning as in the above formula (2).)
It can synthesize | combine by reacting with 2 equivalent of diamine represented by these in an appropriate solvent (for example, tetrahydrofuran) preferably. Here, when R ¹ is a single bond, the reactivity of the two amino groups in the diamine is equivalent;
When R ¹ is a methylene group or an alkylene group having 2 to 6 carbon atoms, the amino group bonded to R ¹ is more reactive. For example, a predetermined amount of diamine is dissolved in a suitable solvent, and The desired compound represented by the above formula (2) can be obtained in a high yield by a method of adding isocyanate little by little.
In the above formula (2), n1 is 1, X is an oxygen atom, Y on the R ¹ side is an oxygen atom, and Y on the R ² side is —NH—. 1 equivalent of diisocyanate represented by ^2- NCO (wherein R ² has the same meaning as in the above formula (2)), and the following formula

(In the above formula, R ¹ has the same meaning as in the above formula (2).)
The compound can be synthesized by reacting with 2 equivalents of a compound represented by the formula (II) preferably in an appropriate solvent (for example, toluene) and then reducing the nitro group.

As the diamine for synthesizing the polyamic acid, only the compound represented by the above formula (2) may be used, or other diamine may be used in combination with the compound represented by the above formula (2). Good.
Examples of other diamines that can be used here include diamines having pretilt angle expression and diamines having no pretilt angle expression.

  Examples of the diamine having the pretilt angle expression include dodecanoxy-2,4-diaminobenzene, tetradecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy- 2,4-diaminobenzene, dodecanoxy-2,5-diaminobenzene, tetradecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diaminobenzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diamino Benzene, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenze Cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostannyl 3,5-diaminobenzoate, 3,6-bis (4-aminobenzoyloxy) cholestane, 3,6-bis (4- Aminophenoxy) cholestane, the following formula (A-1)

(In the formula (A-1), X ^I and X ^II are each a single bond, ^* —O—, ^* —COO— or ^* —OCO— (where the bond marked with “*” is the formula (A -I) is directed to the left direction), and R ^I is a single bond, a methylene group or an alkylene group having 2 or 3 carbon atoms, a is 0 or 1, and b is an integer of 0-2. However, a and b are not 0 simultaneously, and c is an integer of 1 to 20.)
And diamines described in Patent Document 4 (Japanese Patent Laid-Open No. 2010-97188), and one or more selected from these can be used.
Specific examples of the group C _c H _{2c + 1} — in the above formula (A-1) include, for example, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, and n-heptyl. Group, n-octyl group, n-nonyl group, n-decyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group Group, n-nonadecyl group, n-eicosyl group and the like.
The formula ^{(A-1) X I -R} I -X II in - a divalent methylene group as a group, an alkylene group having 2 or 3 carbon atoms ^represented, * ^-O-, * -COO- or ^* It is preferably —O—CH ₂ CH ₂ —O— (wherein a bond marked with “*” is bonded to a diaminophenyl group). The two amino groups in the diaminophenyl group are preferably in the 2,4-position or 3,5-position with respect to the other groups.
Specific examples of the compound represented by the formula (A-1) include, for example, the following formulas (A-1-1-1), (A-1-1-2), and (A-1-2).

(In the above formula, n-C ₅ H ₁₁ and n-C ₇ H ₁₅ represent a linear pentyl group and a linear heptyl group, respectively.)
It is preferable that it is a compound represented by each of these.

Examples of the diamine having no pretilt angle developing group include aliphatic diamines, alicyclic diamines, diaminoorganosiloxanes, aromatic diamines, and the like having no pretilt angle developing group. It is preferable to use one or more selected.
Examples of the aliphatic diamine having no pretilt angle-expressing group include 1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and the like;
Examples of the alicyclic diamine having no pretilt angle developing group include 1,4-diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, and the like;
Examples of the diaminoorganosiloxane having no pretilt angle developing group include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane;

Examples of the aromatic diamine having no pretilt angle-expressing group include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, , 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 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylidene) 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-diaminocarbazole, N-methyl-3,6-diamino Carbazole, 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-diamino Benzoic acid, 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) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis ( 4-((aminophenoxy) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, 2,4-diamino -N, N-diallylaniline, 4-aminobenzylamine, 3-aminobenzylamine, 1- (2, 4-diaminophenyl) piperazine-4-carboxylic acid, 4- (morpholin-4-yl) benzene-1,3-diamine, 1,3-bis (N- (4-aminophenyl) piperidinyl) propane, α-amino -Ω-aminophenylalkylene, 4- (4-aminophenoxycarbonyl) -1- (4-aminophenyl) piperidine and the like can be mentioned, and each can be mentioned, and Patent Document 4 (Japanese Patent Laid-Open No. 2010-97188). Diamines described in Japanese Patent Publication No. 1), and one or more selected from these can be used.

The diamine for synthesizing the polyamic acid in the present invention preferably contains the specific diamine as described above in an amount of 10 mol% or more with respect to the total amount of the diamine, and contains 20 to 90 mol%. Is more preferable, and it is particularly preferable to contain 30 to 70 mol%.
The diamine for synthesizing the polyamic acid can contain the diamine having the pretilt angle expression as described above in a range of 40 mol% or less with respect to the total amount of the diamine. The content is preferably not more than mol%, more preferably not more than 10 mol%, and particularly preferably not containing it.

[Molecular weight regulator]
When synthesizing the polyamic acid as the specific polymer, a terminal-modified polymer may be synthesized using an appropriate molecular weight regulator together with the tetracarboxylic dianhydride and dimian. By using a polyamic acid as such a terminal-modified polymer, the applicability (printability) of the liquid crystal aligning agent obtained without impairing the effects of the present invention can be further improved.
As said molecular weight regulator, an acid monoanhydride, a monoamine compound, a monoisocyanate compound etc. can be mentioned, for example.
Examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, n -Hexadecyl succinic anhydride etc .;
Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine;
Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.
The use ratio of the molecular weight regulator is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass in total of the tetracarboxylic dianhydride and diamine used.

[Method of synthesizing polyamic acid]
The polyamic acid which is the specific polymer in the present invention can be synthesized by reacting tetracarboxylic dianhydride and diamine in a solvent. The proportion of tetracarboxylic dianhydride and diamine used in the polyamic acid synthesis reaction is 0.2 to 2 equivalents of tetracarboxylic dianhydride acid anhydride group to 1 equivalent of amino group of diamine. The ratio which becomes is preferable, and the ratio which becomes 0.3-1.2 equivalent is more preferable.
As a solvent used for the synthesis of polyamic acid, an organic solvent is preferable. Examples of the organic solvent include aprotic polar solvents, phenol and derivatives thereof, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons and the like. Specific examples thereof include the above aprotic polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexa Methylphosphotriamide, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide and the like;
Examples of the phenol and derivatives thereof include phenol, m-cresol, xylenol, and halogenated phenol;
Examples of the alcohol include methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, and ethylene glycol monomethyl ether;
Examples of the ketone include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone;

Examples of the ester include ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, and diethyl malonate;
Examples of the ether include diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether, 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 acetate, tetrahydrofuran and the like;
Examples of the halogenated hydrocarbon include dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene and the like;
Examples of the hydrocarbon include hexane, heptane, octane, benzene, toluene, xylene, isoamylpropionate, isoamylisobutyrate, diisopentyl ether, and the like, and one selected from these The above can be used.

Among these organic solvents, one or more selected from the group consisting of aprotic polar solvents and phenol and derivatives thereof (first group organic solvent) are used, or selected from the first group of organic solvents It is preferable to use a mixture of at least one selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second-group organic solvent). In the latter case, the use ratio of the second group of organic solvents is preferably 50% by mass or less, and preferably 40% by mass or less, with respect to the total of the first group of organic solvents and the second group of organic solvents. More preferably, it is more preferably 30% by mass or less.
As the solvent used for the synthesis of the polyamic acid in the present invention, it is more preferable to use one or more selected from the first group of organic solvents, and one or more selected from aprotic polar solvents are used. It is more preferable to use N-methyl-2-pyrrolidone.
The proportion of the solvent used is preferably such that the total amount of tetracarboxylic dianhydride and diamine is 0.1 to 50% by mass with respect to the total amount of the reaction solution.
The synthesis of the polyamic acid which is the specific polymer in the present invention is preferably at a reaction temperature of -20 to 150 ° C, more preferably 0 to 100 ° C, preferably 0.1 to 24 hours, more preferably 0.5 to It can be carried out with a reaction time of 12 hours.

As described above, a reaction solution obtained by dissolving the polyamic acid as the specific polymer is obtained.
This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution. Or after purifying the isolated polyamic acid, you may use for preparation of a liquid crystal aligning agent. Isolation and purification of said polyamic acid can each be performed in accordance with a well-known method.

[Method for synthesizing imidized polymer]
The imidized polymer as the specific polymer contained in the liquid crystal aligning agent of the present invention can be obtained by dehydrating and ring-closing and imidizing the polyamic acid obtained as described above. In this case, the reaction solution of the polyamic acid synthesized above may be used for the dehydration ring-closing reaction as it is, or the polyamic acid contained in the reaction solution may be isolated and then used for the dehydration ring-closing reaction, or isolated. The polyamic acid may be purified and then subjected to a dehydration ring closure reaction.
The imidized polymer that is the specific polymer in the present invention may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure that the polyamic acid that is the precursor thereof has, and part of the amic acid structure. A partially imidized product in which only an amic acid structure and an imide ring structure coexist may be used. The imidized polymer in the present invention preferably has an imidation ratio of 30% or more, more preferably 50 to 99%, and still more preferably 65 to 99%. This imidation ratio represents the ratio of the number of imide ring structures to the total of the number of polyimide amic acid structures and the number of imide ring structures in percentage. Here, even if a part of the imide ring is an isoimide ring, it may be included as an imide ring.
The dehydration cyclization reaction of the polyamic acid is preferably performed by a method of heating the polyamic acid or a method of adding a dehydrating agent and a dehydration cyclization catalyst to a solution obtained by dissolving the polyamic acid in an organic solvent and heating as necessary. It is more preferable to use the method.

In the method of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used as the dehydrating agent. The use ratio of the dehydrating agent is preferably 0.01 to 20 mol with respect to 1 mol of the amic acid structure of the polyamic acid. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. The use ratio of the dehydration ring-closing catalyst is preferably 0.01 to 10 mol with respect to 1 mol of the dehydrating agent used. Examples of the organic solvent used for the dehydration ring-closing reaction include the organic solvents exemplified above as those used for the synthesis of the polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.
As described above, a reaction solution containing an imidized polymer is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent after removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution. It may be used for preparation of a liquid crystal aligning agent, or may be used for preparation of a liquid crystal aligning agent after purifying the isolated polyimide. These operations can be performed according to known methods.

[Solution viscosity of specific polymer]
The specific polymer (at least one selected from the group consisting of polyamic acid and imidized polymer) in the present invention obtained as described above is 20 to 800 mPa when this is a 10% by mass solution. It is preferable to have a solution viscosity of s, and more preferable to have a solution viscosity of 30 to 500 mPa · s. Here, the solution viscosity (mPa · s) of the specific polymer is determined using an E-type rotational viscometer for the specific polymer solution having a concentration of 10% by mass prepared using N-methyl-2-pyrrolidone as a solvent. It is a value measured at 25 ° C.

<Other ingredients>
Although the liquid crystal aligning agent of this invention contains the above specific polymers, it may contain other arbitrary components as needed. As other optional components, for example, a polymer other than the above specific polymer (hereinafter referred to as “other polymer”), a compound having one or more epoxy groups in the molecule (hereinafter referred to as “epoxy compound”). ), Functional silane compounds and the like.

[Other polymers]
The other polymer can be contained in the liquid crystal aligning agent of the present invention for the purpose of improving the solution characteristics of the liquid crystal aligning agent and the electric characteristics of the obtained liquid crystal aligning film.
The other polymer in the present invention is a polymer other than the specific polymer, and a polyamic acid having no divalent group represented by the above formula (1), an imidized polymer of the polyamic acid, a polyamic Examples include acid esters, polyesters, polyamides, polyorganooxanes, cellulose derivatives, polyacetals, polystyrene or derivatives thereof, poly (styrene-phenylmaleimide) derivatives, poly (meth) acrylates, and the like. One or more can be used.
The content ratio of the other polymer in the liquid crystal aligning agent of the present invention is 50% by mass or less with respect to the total of the polymers (the total of the specific polymer and the other polymer; the same shall apply hereinafter). Is preferable, it is more preferable to set it as 40 mass% or less, and it is further more preferable to set it as 30 mass% or less. When the liquid crystal aligning agent of the present invention contains another polymer, the content ratio is 0.1% by mass or more, preferably 5% by mass or more, based on the total amount of the polymer, so that solution characteristics and electrical characteristics are obtained. Effects such as improvement are fully expressed.

[Epoxy compound]
When the liquid crystal aligning agent of this invention contains an epoxy compound, effects, such as the improvement of the mechanical strength of a liquid crystal aligning film and the improvement of the adhesiveness between the liquid crystal aligning film formed and a board | substrate, express.
Examples of the epoxy compound include compounds having two or more epoxy groups in the molecule. Specifically, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl. 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-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, , N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, N, N-diglycidyl-cyclohexylamine and the like. One or more selected from these can be used.
The content ratio of the epoxy compound in the liquid crystal aligning agent of the present invention is preferably 40 parts by mass or less, more preferably 0.1 to 30 parts by mass with respect to 100 parts by mass in total of the polymer.

[Functional silane compounds]
By including the functional silane compound in the liquid crystal aligning agent of the present invention, there are effects such as improvement in the coating property (printability) of the liquid crystal aligning agent and improvement in adhesion between the liquid crystal aligning film to be formed and the substrate. To express.
Examples of such functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl). ) -3-Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3- Aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl- , 4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-trimethoxysilyl-3,6-diazanonyl acetate , 9-triethoxysilyl-3,6-diazanonyl acetate, methyl 9-trimethoxysilyl-3,6-diazananoate, methyl 9-triethoxysilyl-3,6-diazananoate, N-benzyl-3- Aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, glycidoxymethyltrimethoxysilane, Glycidoxymethyltriethoxysilane, 2-glycidoxyethylate And methoxysilane, 2-glycidoxyethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like. Can be used.
The content ratio of the functional silane compound in the liquid crystal aligning agent of the present invention is preferably 2 parts by mass or less, and preferably 0.02 to 0.2 parts by mass with respect to 100 parts by mass in total of the polymer. More preferred.

<Preparation of liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention is a solution composition containing the above specific polymer as an essential component and containing other optional components dissolved in a suitable organic solvent as necessary. It is preferable to be prepared.
Examples of the organic solvent used in the liquid crystal aligning 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-i-propyl 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 acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, etc. 1 or more types selected from these can be used.

The organic solvent used in the liquid crystal aligning agent of the present invention is preferably an aprotic polar solvent because of the high solubility of the specific polymer, and is selected from N-methyl-2-pyrrolidone and γ-butyrolactone. It is more preferable to use one or more types. One or more solvents selected from the group consisting of ethylene glycol-n-butyl ether (butyl cellosolve), diethylene glycol diethyl ether and 4-hydroxy-4-methyl-2-pentanone as long as the solubility of the specific polymer is not inhibited. Furthermore, you may contain.
The solid content concentration in the liquid crystal aligning agent of the present invention (the ratio of the total mass of components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, and the like. , Preferably it is the range of 1-10 mass%. By setting it as solid content concentration of this range, it can be set as the liquid crystal aligning agent excellent in the balance of applicability | paintability (printability) and a film thickness.
The particularly preferable solid content concentration and solution viscosity range vary depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, in the case of the spinner method, the solid content concentration is preferably in the range of 1.5 to 4.5% by mass, and thereby the solution viscosity is preferably in the range of 4 to 13 mPa · s. In the case of the printing method, the solid content concentration is preferably in the range of 3 to 9% by mass, and thereby the solution viscosity is preferably in the range of 12 to 50 mPa · s. In the case of the ink jet method, the solid content concentration is preferably in the range of 1 to 5% by mass, and the solution viscosity is preferably in the range of 3 to 15 mPa · s.
The temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 10-50 degreeC, More preferably, it is 20-30 degreeC.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment film of this invention is formed from said liquid crystal aligning agent.
The liquid crystal alignment film of the present invention is a horizontal alignment type liquid crystal display element such as TN mode, STN mode, IPS, FFS mode;
The present invention may be applied to any vertical alignment type liquid crystal display element such as a VA mode. However, since the liquid crystal aligning agent of the present invention provides a liquid crystal alignment film having excellent rubbing resistance, it is preferably applied to a horizontal alignment type liquid crystal display element that is frequently subjected to rubbing treatment in the film forming process. It is more preferable to apply to a mode liquid crystal display element.
The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3). In the step (1), the substrate to be used is different for each desired operation mode. Steps (2) and (3) are common to each operation mode.

[Step (1): Formation of coating film]
First, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, Then, a coating film is formed on a board | substrate by heating an application surface.
(1-1) When manufacturing a TN mode, STN mode or VA mode liquid crystal display element:
As a pair of two substrates provided with a patterned transparent conductive film, the liquid crystal aligning agent of the present invention is preferably applied to each transparent conductive film forming surface, preferably by an offset printing method, a spin coating method, a roll coater method. Or it coats by the inkjet printing method, respectively, Then, a coating film is formed by heating each coating surface.
Examples of the substrate include glass such as float glass and soda glass;
A transparent substrate made of a resin such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly (alicyclic olefin) can be used.
As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. In order to obtain a patterned transparent conductive film which can be used, for example, a method of forming a pattern by photo-etching after forming a transparent conductive film without a pattern, a mask having a desired pattern when forming the transparent conductive film The method using can be used.
In order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional silane compound is formed on the surface of the substrate surface on which the coating film is to be formed prior to the application of the liquid crystal aligning agent. Alternatively, a pretreatment for heating after applying a functional titanium compound or the like in advance may be performed.
A coating film is formed by subsequently applying the coated surface after the application of the liquid crystal aligning agent. This heating is preferably two-stage heating consisting of preheating (pre-baking) and baking (post-baking). The pre-bake conditions are, for example, 0.1 to 5 minutes at 40 to 120 ° C., and the post-bake conditions are preferably 120 to 300 ° C., more preferably 150 to 250 ° C., preferably 5 to 200 minutes, more preferably 10 to 100 minutes.
The film thickness of the formed coating film is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.

(1-2) When manufacturing an IPS mode or FFS mode liquid crystal display element:
As the pair of substrates, a substrate provided with a transparent conductive film patterned in a comb shape and a substrate provided with no conductive film are used.
The liquid crystal aligning agent of the present invention is applied to each of the conductive film forming surface of the substrate provided with the transparent conductive film and one surface of the substrate not provided with the conductive film, and then the respective coated surfaces are heated to be applied. A film is formed. Regarding the material of the substrate used at this time, the material of the transparent conductive film, the patterning method of the transparent conductive film, the coating method, the heating conditions after coating, the pre-treatment of the substrate and the preferred film thickness of the coating film to be formed are as described above ( It is the same as 1-1).
In both cases (1-1) and (1-2), after applying a liquid crystal aligning agent on the substrate, a coating film to be a liquid crystal aligning film is formed by removing the organic solvent. At this time, when the polymer contained in the liquid crystal aligning agent of the present invention is a polyamic acid or a partially imidized polymer having both an imide ring structure and an amic acid structure, Furthermore, it is good also as a more imidized coating film by advancing dehydration ring-closing reaction by heating.

[Step (2): rubbing treatment]
When manufacturing a TN mode, STN mode, IPS mode or FFS mode liquid crystal display element, a cloth made of long fibers such as nylon, rayon, cotton, etc. was wrapped around the coating film formed as described above. A rubbing process of rubbing in a certain direction with a roll is performed. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film.
A treatment for changing the pretilt angle of a part of the liquid crystal alignment film by irradiating part of the liquid crystal alignment film with ultraviolet rays, and forming a resist film on a part of the liquid crystal alignment film surface. By performing the rubbing process in the direction different from the previous rubbing process and removing the resist film so that the liquid crystal alignment film has different liquid crystal alignment ability for each region, the liquid crystal display element obtained It is possible to improve the visibility characteristics.
When manufacturing a VA mode liquid crystal display element, the coating film formed as described above can be used as it is as a liquid crystal alignment film without being subjected to the rubbing treatment. May be.

[Step (3): Production of liquid crystal display element]
Next, a liquid crystal cell having a structure in which the liquid crystal is sandwiched in a gap (cell gap) in which the pair of substrates on which the liquid crystal alignment film is formed as described above is arranged to face each other is configured.
To configure the liquid crystal cell,
The two substrates on which the liquid crystal alignment film is formed are bonded so that the liquid crystal alignment film surface faces each other by the sealant disposed on the periphery thereof, and the liquid crystal is placed in the cell gap defined by the liquid crystal alignment film surface and the sealant. Filling and filling the injection hole;
For example, an ultraviolet curable sealant is disposed at a predetermined position on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystal is disposed at predetermined positions on the liquid crystal alignment film surface. By sticking and pressing the other substrate so that the liquid crystal alignment film faces each other, the liquid crystal is spread on the front surface of the liquid crystal alignment film, and then the entire surface of the substrate is irradiated with ultraviolet rays to cure the sealing agent. it can.
In any of the above cases, when the rubbing treatment is performed during the formation of the liquid crystal alignment film, the rubbing directions of the liquid crystal alignment films of the two substrates are preferably arranged so as to be orthogonal or antiparallel.
And a liquid crystal display element can be manufactured by bonding a polarizing plate on the outer surface of a liquid crystal cell in a predetermined direction.

As the sealant, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.
As the liquid crystal, nematic liquid crystal or smectic liquid crystal can be used. Of these, nematic liquid crystal is preferable. Specific examples include Schiff-based liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenyl cyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals, biphenyl cyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, and bicyclooctane liquid crystals. And Cuban liquid crystal. For example, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, and cholesteryl carbonate;
Chiral agents such as those sold under the product names “C-15” and “CB-15” (Merck);
Ferroelectric liquid crystals such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate may be added and used.
As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, for example, a polarizing plate in which a polarizing film called “H film” in which iodine is absorbed while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films, or H Examples thereof include a polarizing plate made of the film itself.
The liquid crystal display element obtained as described above can be effectively applied to various devices, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, and mobile phones. In addition, it can be used for display devices such as various monitors and liquid crystal televisions.

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

<Synthesis of diamine>
In each of the following synthesis examples, the necessary amount used for the synthesis of the subsequent polymer was ensured by repeating the synthesis on the scale described below as necessary.
Synthesis Example A-1
According to the following scheme 1, compound (2-1-3) was synthesized.

  In a 5 L separable flask equipped with a stirrer and a nitrogen inlet tube, 268.4 g of 4-aminobenzylamine was dissolved in 2,750 mL of tetrahydrofuran, and 92.4 g of hexamethylene diisocyanate was slowly added thereto. It was recovered by filtration. This precipitate was recrystallized from N, N-dimethylacetamide to obtain 181.5 g of (2-1-3) white crystals.

Synthesis Example A-2
Compound (2-1-5) was synthesized according to the following scheme 2.

  In the above Synthesis Example A-1, compound (1-1-5) was prepared in the same manner as in Synthesis Example A-1, except that 299.2 g of 2- (4-aminophenyl) ethylamine was used instead of 4-aminobenzylamine. ) 188.1 g of white crystals were obtained.

Synthesis Example A-3
Compound (2-6-5) was synthesized according to the following scheme 3.

(1) Synthesis of Compound (2-6-5a) In a 500 mL three-necked flask equipped with a thermometer, a nitrogen introduction tube and a dropping funnel, 36.8 g of 4-nitrophenethyl alcohol and 200 mL of toluene were charged.
Meanwhile, 16.8 g of 1,6-hexamethylene diisocyanate and 50 mL of toluene were charged into the dropping funnel.
While the temperature of the flask contents was maintained at 15 to 25 ° C., the dropping funnel contents were slowly dropped. After completion of the dropping, the reaction was carried out at 80 ° C. with stirring for 1 hour. After completion of the reaction, the reaction mixture was poured into 2 L of methanol and the resulting precipitate was collected by filtration to obtain 45.2 g of compound (2-6-5a).
(2) Synthesis of compound (2-6-5) In a 1 L three-necked flask equipped with a reflux tube and a thermometer, the total amount of compound (2-6-5a) obtained above (45.2 g), 5 wt. % Palladium on carbon (2.3 g) and N, N-dimethylformamide (500 mL) were charged, and the inside was depressurized using an aspirator. Next, after a balloon filled with 3 L of hydrogen gas was attached to the reactor and the system was filled with hydrogen gas, the reaction was performed at 60 ° C. with stirring for 4 hours. After completion of the reaction, palladium carbon was removed by Celite filtration, and then the filtrate was concentrated under reduced pressure. The precipitated crystals were collected by filtration to collect 35.4 g of white crystals of the compound (2-6-5). Obtained.

<Synthesis of polymer>
The solution viscosity of the polymer in each of the following synthesis examples is a value measured at 25 ° C. using an E-type rotational viscometer.
Synthesis Example P-1
11 g (0.05 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 190 g (0.95 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 4-aminophenyl as diamine = 71 g (0.31 mol) of 4-aminobenzoate, 110 g (0.29 mol) of 4,4 ′-[4,4′-propane-1,3-diylbis (piperidine-1,4-diyl)] dianiline and 170 g (0.40 mol) of the compound (2-1-3) obtained in Synthesis Example A-1 is dissolved in 3,100 g of N-methyl-2-pyrrolidone (NMP) and reacted at 40 ° C. for 6 hours. As a result, a solution containing 15% by mass of polyamic acid (PA-1) was obtained. The solution viscosity of this solution was 400 mPa · s.
Synthesis Example P-2
In Synthesis Example P-1, 180 g (0.40 mol) of Compound (2-1-5) obtained in Synthesis Example A-2 was used instead of Compound (2-1-3), and NMP was used. A solution containing 15% by mass of polyamic acid (PA-2) was obtained in the same manner as in Synthesis Example P-1, except that the amount was 3,200 g. The solution viscosity of this solution was 420 mPa · s.

Synthesis Example P-3
200 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 130 g (0. 0. 2,2'-dimethyl-4,4'-diaminobiphenyl as diamine) 6 mol) and 180 g (0.40 mol) of the compound (2-1-5) obtained in Synthesis Example A-2 above were dissolved in 4,600 g of NMP and reacted at 40 ° C. for 3 hours to obtain a polyamic acid ( A solution containing 15% by mass of PA-3) was obtained. The solution viscosity of this solution was 160 mPa · s.
Synthesis example P-4
200 g (0.90 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 22 g (0.100 mol) of 1,2,3,5-tricarboxycyclopentylacetic acid dianhydride and p-phenylenediamine as diamine 22 g (0.20 mol), 4,4-diaminodiphenyl ether 20 g (0.10 mol), 3,5-diaminobenzoic acid 46 g (0.30 mol) and the compound (2- 1-5) 180 g (0.40 mol) is dissolved in a mixed solvent composed of 1,400 g of NMP and 1,400 g of γ-butyrolactone (γ-BL), and reacted at 40 ° C. for 4 hours, whereby polyamic acid ( A solution containing 15% by mass of PA-4) was obtained. The solution viscosity of this solution was 410 mPa · s.

Comparative Synthesis Example P-5
11 g (0.05 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 190 g (0.95 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 4-aminophenyl as diamine = 160 g (0.71 mol) of 4-aminobenzoate and 110 g (0.29 mol) of 4,4 ′-[4,4′-propane-1,3-diylbis (piperidine-1,4-diyl)] dianiline. , NMP 1,300 g and γ-BL 1,300 g, was dissolved in a mixed solvent and reacted at 40 ° C. for 6 hours to obtain a solution containing 15% by mass of polyamic acid (PA-5). The solution viscosity of this solution was 420 mPa · s.
Comparative Synthesis Example P-6
Pyromellitic dianhydride 40 g (0.20 mol) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride 160 g (0.80 mol) as tetracarboxylic dianhydride and 4-aminophenyl as diamine = 140 g (0.62 mol) of 4-aminobenzoate, 110 g (0.29 mol) of 4,4 ′-[4,4′-propane-1,3-diylbis (piperidine-1,4-diyl)] dianiline and 26 g (0.09 mol) of diethylene glycol (di-4-aminophenyl) ether was dissolved in a mixed solvent consisting of 1,400 g of NMP and 1,400 g of γ-BL, and reacted at 40 ° C. for 6 hours to obtain a polyamic acid ( A solution containing 15% by mass of PA-6) was obtained. The solution viscosity of this solution was 850 mPa · s.

Comparative Synthesis Example P-7
200 g (0.90 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 22 g (0.10 mol) of 1,2,3,5-tricarboxycyclopentylacetic acid dianhydride and p-phenylenediamine as diamine 22 g (0.20 mol), 4,4-diaminodiphenyl ether 100 g (0.50 mol) and 3,5-diaminobenzoic acid 46 g (0.30 mol) mixed with NMP 1,100 g and γ-BL 1,100 g By dissolving in a solvent and reacting at 40 ° C. for 4 hours, a solution containing 15% by mass of polyamic acid (PA-7) was obtained. The solution viscosity of this solution was 410 mPa · s.
Comparative Synthesis Example P-8
11 g (0.05 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 190 g (0.95 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 4-aminophenyl as diamine = 120 g (0.51 mol) of 4-aminobenzoate, 110 g (0.29 mol) of 4,4 ′-[4,4′-propane-1,3-diylbis (piperidine-1,4-diyl)] dianiline and 62 g (0.20 mol) of 4- (4-aminophenoxycarbonyl) -1- (4-aminophenyl) piperidine was dissolved in a mixed solvent consisting of 1,400 g of NMP and 1,400 g of γ-BL, and at 40 ° C. for 6 hours. By performing the reaction, a solution containing 15% by mass of polyamic acid (PA-8) was obtained. The solution viscosity of this solution was 420 mPa · s.

Comparative Synthesis Example P-9
200 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 210 g of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine (1. 0 mol) was changed to 3,700 g of NMP, and the reaction was carried out at 40 ° C. for 3 hours to obtain a solution containing 15% by mass of polyamic acid (PA-9). The solution viscosity of this solution was 160 mPa · s.
Comparative Synthesis Example P-10
11 g (0.05 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 190 g (0.95 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 4-aminophenyl as diamine = 71 g (0.31 mol) of 4-aminobenzoate, 110 g (0.29 mol) of 4,4 ′-[4,4′-propane-1,3-diylbis (piperidine-1,4-diyl)] dianiline and 120 g (0.40 mol) of a compound represented by the following formula (R-1) is dissolved in 2,800 g of NMP and reacted at 40 ° C. for 6 hours to contain 15% by mass of polyamic acid (PA-10). A solution was obtained. The solution viscosity of this solution was 40 mPa · s.

Synthesis Example P-11
1.1 g (0.005 mol) of pyromellitic dianhydride as tetracarboxylic dianhydride and 19 g (0.095 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 4-diamine as diamine Aminophenyl 4-aminobenzoate 7.1 g (0.031 mol), 4,4 ′-[4,4′-propane-1,3-diylbis (piperidine-1,4-diyl)] dianiline 11 g (0. 029 mol) and 18 g (0.040 mol) of the compound (2-6-5) obtained in Synthesis Example A-3 above were dissolved in 318 g of NMP and reacted at 40 ° C. for 6 hours to obtain a polyamic acid (PA- A solution containing 11% by weight of 11) was obtained. The solution viscosity of this solution was 380 mPa · s.

<Preparation and evaluation of liquid crystal aligning agent>
Example 1
(1) Preparation of liquid crystal aligning agent N, N, N ′, N′-tetraglycidyl-4,4 ′ was added to a solution containing 15% by mass of the polyamic acid (PA-1) obtained in Synthesis Example P-1. -5 parts by mass of diaminodiphenylmethane with respect to 100 parts by mass of polyamic acid in the polyamic acid solution, and further γ-BL, NMP and butyl cellosolve (BC) are added, and the solvent composition is γ-BL: NMP: BC = 40. : 40:20 (mass ratio), and a solid content concentration of 4.0 mass%. A liquid crystal aligning agent was prepared by filtering this solution through a filter having a pore diameter of 0.45 μm.
(2) Evaluation of rubbing resistance The liquid crystal aligning agent prepared above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spin coater and heated on a hot plate at 80 ° C. for 1 minute ( After removing the solvent by pre-baking, the film was heated (post-baked) for 15 minutes by nitrogenation in a clean oven at 230 ° C. to form a coating film having an average film thickness of 100 nm. This coating film was rubbed five times with a rubbing machine having a roll wound with a cotton cloth at a roll rotation speed of 1,000 rpm, a stage moving speed of 2 cm / sec, and a hair foot indentation length of 0.4 mm. The rubbing treatment conditions are accelerated tests that are considerably stricter than the rubbing treatment performed in the actual liquid crystal alignment film forming step.
The coating film after the rubbing treatment was observed with an optical microscope, and the number of foreign matters (peeled objects having a major axis of 1 μm or more) in a 500 μm × 500 μm region (0.25 mm ² ) was counted. As a result, the result was “good”.
Foreign matter 4 pieces / 0.25 mm ² or less: Good Foreign matter 5-10 pieces / 0.25 mm ² : Defect Foreign matter 11 pieces / 0.25 mm ² or more: Extremely bad

(3) Evaluation of Transparency The liquid crystal aligning agent prepared above was applied onto a quartz substrate using a spin coater, heated (prebaked) on an 80 ° C. hot plate for 1 minute to remove the solvent, and then 230 The film was heated (post-baked) for 15 minutes by nitrogenation in a clean oven at 0 ° C. to form a coating film having an average film thickness of 100 nm. With respect to the quartz substrate on which this coating film was formed, an ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation, product name “V-670”) was used as a reference for the same type of quartz substrate having no coating film. When the absorption spectrum in the visible light region was measured and the transmittance at a wavelength of 400 nm was examined, it was 95%.

(4) Evaluation of liquid crystal orientation The liquid crystal aligning agent prepared above is applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using spin coating, and heated on a hot plate at 80 ° C for 1 minute ( After removing the solvent by pre-baking, the film was heated (post-baked) for 15 minutes by nitrogenation in a clean oven at 230 ° C. to form a coating film having an average film thickness of 100 nm. This coating film is rubbed with a rubbing machine having a roll wrapped with a cotton cloth under the conditions of a roll rotation speed of 1,000 rpm, a stage moving speed of 2 cm / sec, and a hair foot indentation length of 0.4 mm. A liquid crystal alignment film was formed by imparting liquid crystal alignment ability to the film. Next, after ultrasonic cleaning for 1 minute in ultrapure water, the substrate having a liquid crystal alignment film was obtained by drying in a clean oven at 100 ° C. for 10 minutes. The above operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film.
After applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm to the outer edge of the surface having the liquid crystal alignment film of one of the pair of substrates, the liquid crystal alignment film surfaces face the pair of substrates. The adhesive was cured by overlapping and pressing. Next, a nematic liquid crystal (MLC-2042, manufactured by Merck & Co., Inc.) was filled between the substrates through the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photo-curing adhesive to produce a liquid crystal cell.
The liquid crystal cell produced above was observed with a microscope for the presence and extent of abnormal domains under crossed Nicols, and the liquid crystal alignment was evaluated according to the following criteria. Microscope observation was performed by copying an area of 500 μm × 500 μm on the liquid crystal alignment film surface onto a monitor attached to the microscope and scanning this little by little.
When the abnormal domain is not observed: Good When the abnormal domain is observed in a part of the cell: Bad When the abnormal domain is observed over the entire surface of the cell: Very bad

Examples 2-5 and Comparative Examples 1-6
In Example 1 above, a liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 1 except that the type of polyamic acid contained in the used polyamic acid solution was changed as shown in Table 1.
The evaluation results are shown in Table 1.

Claims (6)

Liquid crystal alignment characterized by containing at least one polymer selected from the group consisting of a polyamic acid having a divalent group represented by the following formula (1) and an imidized polymer of the polyamic acid Agent.

(In the formula (1), n1 is an integer of 1 to 3;
A plurality of X are each independently an oxygen atom or a sulfur atom;
A plurality of Y are each independently —NH— or an oxygen atom;
Two R ^{1 s} are each independently a single bond, a methylene group or an alkylene group having 2 to 6 carbon atoms;
R ² is each independently a divalent organic group when there are a plurality of R ² ;
“*” Represents a bond. ) R ² in the formula (1) is a hydrocarbon group or a halogenated hydrocarbon group having 1 to 30 carbon atoms, a liquid crystal aligning agent of claim 1. N1 in the above formula (1) is 1;
The liquid crystal aligning agent according to claim 1 or 2, wherein X is an oxygen atom; and Y is -NH-. The polymer is selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic dianhydride and a diamine containing a compound represented by the following formula (2) and an imidized polymer of the polyamic acid. The liquid crystal aligning agent as described in any one of Claims 1-3 which is at least 1 sort by which it is carried out.

(In the formula (2), n1, X, Y, R ¹ and R ² have the same meanings as in the formula (1)).   The liquid crystal aligning film formed from the liquid crystal aligning agent as described in any one of Claims 1-4. A liquid crystal display device comprising the liquid crystal alignment film according to claim 5.