TW201317689A - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

This liquid crystal alignment agent contains a polyamic acid ester having repeating units represented by formula (1), and an organic solvent. (In formula (1): X1 is a tetravalent organic group; Y1 is a divalent organic group; R1 is an alkyl group with one to five carbons, and includes at least one type of structure selected from a group comprising an amino group, an imino group and a nitrogen-containing heterocycle in X1 and/or Y1; and A1 and A2 are each independently a hydrogen atom, or an alkyl group with one to ten carbons, which may have a substituent, an alkenyl group or an alkynyl group.)

Description

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

The present invention relates to a liquid crystal alignment agent containing a polyphthalate, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element.

It is used for liquid crystal display elements such as liquid crystal televisions and liquid crystal displays, and is usually provided with a liquid crystal alignment film for controlling the arrangement state of liquid crystals. As a liquid crystal alignment film, a liquid crystal alignment agent containing a solution of polyamic acid (or polyamide acid) or soluble polyimine as a main component is applied to a glass substrate or the like and fired. Polyimine-based liquid crystal alignment film.

Along with the high refinement of the liquid crystal display element, it is required to suppress the contrast drop of the liquid crystal display element or to reduce the image sticking phenomenon, in addition to exhibiting excellent liquid crystal alignment or stable pretilt angle on the liquid crystal alignment film, such as high voltage retention rate, alternating current It has become increasingly important to suppress the occurrence of residual images by driving, a small amount of residual charge when a DC voltage is applied, and/or a rapid relaxation of residual charges accumulated by a DC voltage.

On the polyimine-based liquid crystal alignment film, various proposals have been made in order to meet the requirements as described above. For example, it has been proposed to use a liquid crystal alignment film which is a short time required to disappear by a DC voltage to disappear, and a polyamine or a polyamido group containing a ruthenium group is used. A liquid crystal alignment agent of an amine (refer to Patent Document 1) or a specific dimination of a divalent organic group having a nitrogen atom having a pyridine skeleton or the like A liquid crystal alignment agent of a soluble polyimine (a ruthenium iodide polymer) used as a raw material (see Patent Document 2).

[prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. Hei 9-316200

[Patent Document 2] Japanese Patent Laid-Open No. Hei 10-104633

In the liquid crystal display element having the liquid crystal alignment film obtained from the liquid crystal alignment agent of Patent Document 1 or Patent Document 2, the residual charge accumulated by the DC voltage is quickly relaxed. However, as a result of the investigation, the liquid crystal alignment film obtained in Patent Document 1 or Patent Document 2 has been found to have a decrease in light transmittance (hereinafter also referred to as transmittance). The transmittance of the liquid crystal alignment film is lowered, and as a liquid crystal display element, the contrast of the liquid crystal display element is also lowered. The reduction of the contrast can be compensated by increasing the brightness of the backlight, but due to the improvement of the brightness of the backlight, a new problem such as an increase in the power consumption of the backlight occurs.

In order to solve the above problems, an object of the present invention is to provide a liquid crystal alignment agent which obtains a liquid crystal alignment film having a rapid relaxation of a residual charge accumulated by a DC voltage and having a high light transmittance, and a liquid crystal alignment agent obtained from the liquid crystal alignment agent. Film and liquid crystal display elements.

According to the study of the present inventors, it has been found that a polyperurate having a repeating unit represented by the formula (1), which is selected from at least one selected from the group consisting of an amine group, an imine group and a nitrogen-containing hetero ring, is used. As a result, it was found that the relaxation of the residual charge accumulated by the DC voltage was rapid and the transmittance was improved.

Therefore, the present invention has been based on the above findings and has the following points.

A liquid crystal alignment agent characterized by comprising a polyphthalate having a repeating unit represented by the following formula (1) and an organic solvent, (In the formula (1), X ₁ is a tetravalent organic group, Y ₁ is a divalent organic group, and at least one of X ₁ and Y ₁ contains an amine group, an imido group, and a nitrogen-containing heterocyclic ring. At least one of the structures selected from the group consisting of R ₁ is an alkyl group having 1 to 5 carbon atoms, and each of A ₁ and A _{2 is} independently a hydrogen atom or a substituted alkyl group having 1 to 10 carbon atoms. Alkenyl or alkynyl).

2. The liquid crystal alignment agent according to the above-mentioned item 1, wherein Y ₁ in the formula (1) is a divalent organic group containing at least one structure selected from the group consisting of an amine group, an imine group and a nitrogen-containing hetero ring. base.

3. The liquid crystal alignment agent according to the above 1 or 2, wherein Y ₁ is a divalent organic group containing at least one structure selected from the group consisting of an amine group, an imine group, and a nitrogen-containing hetero ring. (1) The proportion of repeating units represented is 40 to 100 mol% relative to the total structural unit of 1 mol.

4. The liquid crystal alignment agent according to any one of the above 1 to 3, wherein Y ₁ is a divalent organic group having a nitrogen atom represented by the following formula (YD-1) to (YD-5) Select at least one of the group, (In the formula (YD-1), A ₁₁ is a trivalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms, and Z ₁ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; In the formula (YD-2), W ₁ is a trivalent hydrocarbon group having 1 to 10 carbon atoms, A ₁₂ is a monovalent organic group having a carbon number of 3 to 15 having a nitrogen-containing hetero ring, or 2 hydrogens of an amine group are each independently a disubstituted amino group substituted with an aliphatic group having 1 to 6 carbon atoms; in the formula (YD-3), W ₂ is a carbon number of 6 to 15, and has a benzene ring of 1 or 2 The group, W ₃ is an alkylene group having a carbon number of 2 to 5 or a phenyl group, and Z ₂ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a benzene ring, and a is 0 or 1, in the formula (YD- In 4), A ₁₃ is a divalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms; in the formula (YD-5), A ₁₄ is a divalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms, and W ₅ is a carbon number. 2~5 alkyl group).

5. The liquid crystal alignment agent according to any one of the above 1 to 4, which is characterized by the formula (YD-1), (YD-2), (YD-4), and (YD-5) ₁₁ , A ₁₂ , A ₁₃ , and A ₁₄ carbon-containing heterocyclic ring having 3 to 15 carbon atoms, which are pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine At least one ring selected from the group consisting of hydrazine, benzimidazole, quinoline and isoquinoline.

6. The liquid crystal alignment agent according to any one of the above 1 to 5, wherein Y ₁ in the formula (1) is a nitrogen represented by the following formula (YD-6) to (YD-23) At least one selected from the group consisting of a divalent organic group of atoms, (In the formula (YD-14), m and n are each an integer from 1 to 11, m+n is an integer from 2 to 12, and in the formula (YD-19), h is an integer from 1 to 3, and the formula (YD- In 16) and (YD-23), j is an integer from 0 to 3.

7. The liquid crystal alignment agent according to any one of the above 1 to 6, wherein X ₁ in the formula (1) is at least one selected from the group consisting of structures represented by the following formulas,

A liquid crystal alignment film which is obtained by coating and baking the liquid crystal alignment agent according to any one of the above 1 to 7.

A liquid crystal display device comprising the liquid crystal alignment film according to the above 8th aspect.

The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention has a high light transmittance, and the liquid crystal display element including the liquid crystal alignment film has a rapid relaxation of the residual electric charge accumulated by the DC voltage.

<Polyurethane>

A polyglycolate containing the liquid crystal alignment agent of the present invention, which is a polyimine precursor of a polyimine, and has a moiety which can be subjected to a ruthenium reaction as shown below by heating. Polymer, (R ₁ is the same as R ₁ in the formula (1)).

The liquid crystal alignment agent of the present invention contains a polyamidate having a repeating unit (structural unit) represented by the following formula (1). Further, the polyperurate having a repeating unit represented by the formula (1), each of R ₁ , A ₁ , A ₂ , X ₁ and Y ₁ may have the same structure. 1) The polyamine phthalate represented by the repeating unit, or may be a repeating unit represented by a plurality of formulas (1) having a plurality of different structures of R ₁ , A ₁ , A ₂ , X ₁ and Y ₁ Poly phthalate. Further, the polyamidate having a repeating unit represented by the formula (1) may be a polyglycolate having a structure other than the repeating unit represented by the formula (1). That is, the polyglycolate which may be a repeating unit represented by the formula (1) of the same structure may also be a polyamidomate composed of repeating units represented by (1) of different structures. Further, a polyamidomate having a repeating unit represented by the formula (1) having the same structure or a different structure and a structure other than the repeating unit represented by the formula (1) (for example, a repeating unit represented by the following formula (2)) Also.

In the above formula (1), R ₁ is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 2 carbon atoms, more preferably a methyl group.

In the formula (1), A ₁ and A ₂ each independently represent a hydrogen atom, or may be a substituted alkyl group having 1 to 10 carbon atoms, an alkenyl group or an alkynyl group. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a tert-butyl group, a hexyl group, an octyl group, a decyl group, a cyclopentyl group, a cyclohexyl group, a dicyclohexyl group and the like. Examples of the alkenyl group include those in which one or more of the above alkyl groups are substituted with a CH-CH structure and a C=C structure, and more specifically, a vinyl group, an allyl group, a 1-propenyl group, an isopropenyl group, and 2 are exemplified. a butenyl group, a 1,3-butadienyl group, a 2-pentenyl group, a 2-hexenyl group, a cyclopropenyl group, a cyclopentenyl group, a cyclohexenyl group or the like. Examples of the alkynyl group include those in which one or more of the above-mentioned alkyl groups are substituted with a CH ₂ -CH ₂ structure C≡C structure, and more specifically, an ethynyl group, a 1-propynyl group, a 2-propynyl group, etc. .

The above-mentioned alkyl group, alkenyl group or alkynyl group may have a substituent as long as the carbon number is from 1 to 10, and may further form a ring structure by a substituent. Further, by forming a ring structure by a substituent, it means that a substituent or a substituent is bonded to a part of the parent skeleton (that is, an atom constituting A ₁ or A ₂ ) to form a ring structure.

Examples of the substituent include a halogen group, a hydroxyl group, a thiol group, a nitro group, an aryl group, an organic oxy group, an organic thio group, an organic decyl group, a decyl group, an ester group, a thioester group, a phosphate group, and an anthracene group. Amine, alkyl, alkenyl, alkynyl.

Examples of the halogen group as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

A phenyl group is mentioned as an aryl group as a substituent. This aryl group may further be substituted with other substituents as described above.

The organooxy group as a substituent can be represented by a structure represented by O-R. The R may be the same or different and may, for example, be an alkyl group, an alkenyl group, an alkynyl group, an aryl group or the like as described above. These R may further be substituted by the aforementioned substituents. Specific examples of the organic oxy group include a methoxy group, an ethoxy group, a propyloxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group and the like.

The organothio group as a substituent can be represented by a structure represented by -S-R. As R, the aforementioned alkyl group, alkenyl group, alkynyl group, and aryl group can be exemplified. These R may further be substituted by the aforementioned substituents. Specific examples of the organic sulfur group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group and the like.

The organoalkylene group as a substituent can be represented by a structure represented by -Si-(R) ₃ . The R may be the same or different and may, for example, be an alkyl group, an alkenyl group, an alkynyl group, an aryl group or the like as described above. These R may further be substituted by the aforementioned substituents. Specific examples of the organic decyl group include a trimethyl decyl group, a triethyl decyl group, a tripropyl decyl group, a tributyl decyl group, a tripentyl decyl group, a trihexyl decyl group, a pentyl dimethyl decyl group, and a hexyl group. Dimethyl hydrazine and the like.

The thiol group as a substituent can be represented by a structure represented by -C(O)-R. As such R, the aforementioned alkyl group, alkenyl group, aryl group and the like can be exemplified. These R may further be substituted by the aforementioned substituents. Specific examples of the mercapto group include a mercapto group, an ethenyl group, a propyl group, a butyl group, an isobutyl group, a pentamidine group, an isovaleryl group, a benzamidine group, and the like.

The ester group as a substituent may be represented by a structure represented by -C(O)O-R or -OC(O)-R. As such R, the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group and the like can be exemplified. These R may further be substituted by the aforementioned substituents.

The thioester group as a substituent may be represented by a structure represented by -C(S)O-R or -OC(S)-R. As such R, the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group and the like can be exemplified. These R may further be substituted by the aforementioned substituents.

The phosphate group as a substituent can be represented by a structure represented by -OP(O)-(OR) ₂ . As such R, the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group and the like can be exemplified. These R may further be substituted by the aforementioned substituents.

The amidino group as a substituent may be represented by -C(O)NH ₂ , or -C(O)NHR, -NHC(O)R, -C(O)N(R) ₂ , -NRC(O ) The structure represented by R. The R may be the same or different and may, for example, be an alkyl group, an alkenyl group, an alkynyl group, an aryl group or the like as described above. These R may further be substituted by the aforementioned substituents. As a substituent which substitutes the hydrogen atom of R, an aryl group is mentioned. The aryl group as the substituent may be the same as the above-mentioned aryl group. This aryl group may further be substituted with the aforementioned substituent.

The alkyl group as a substituent may be the same as the above-mentioned alkyl group. This alkyl group may further be substituted with the aforementioned substituent.

The alkenyl group as a substituent may be the same as the above-mentioned alkenyl group. This alkenyl group may further be substituted with the aforementioned substituent.

The alkynyl group as a substituent is the same as the alkynyl group mentioned above. This alkynyl group may further be substituted with the aforementioned substituent.

In general, as a bulky structure is introduced, there is a possibility that the reactivity of the amine group or the liquid crystal alignment property is lowered. Therefore, as A ₁ and A ₂ , a hydrogen atom or a carbon number having a substituent may be used. The alkyl group of ~5 is more preferable, and a hydrogen atom, a methyl group or an ethyl group is particularly preferable.

In the formula (1), X ₁ is a tetravalent organic group, Y ₁ is a divalent organic group, and at least one of X ₁ and Y ₁ contains an amine group, an imido group and a nitrogen-containing heterocyclic ring. At least one of the selected groups is selected. From the viewpoints of availability of a raw material monomer (that is, a diamine compound or a tetracarboxylic acid derivative, etc.) and ease of manufacture of a raw material monomer, Y ₁ contains an amine group, an imido group, and a nitrogen-containing compound. It is preferred that a divalent organic group having at least one structure selected from the group consisting of heterocyclic rings is preferred. That is to say, the organic group is, for example, a hydrocarbon group having N or O.

When Y ₁ is a divalent organic group having at least one structure selected from the group consisting of an amine group, an imine group, and a nitrogen-containing hetero ring, the structure of Y ₁ contains an amine group, an imine group, and At least one of the groups in which the nitrogen-containing heterocyclic ring is formed is selected, and the structure thereof is not particularly limited. Specific examples thereof include at least one selected from the group consisting of an amine group, an imine group, and a nitrogen-containing hetero ring represented by the following formula (YD-1) to (YD-5). Divalent organic group.

In the formula (YD-1), A ₁₁ is a trivalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms, and Z ₁ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent.

In the formula (YD-2), W ₁ is a trivalent hydrocarbon group having 1 to 10 carbon atoms, and A ₁₂ is a monovalent organic group having a carbon number of 3 to 15 having a nitrogen-containing hetero ring or two hydrogen groups each having an amine group. A disubstituted amine group independently substituted with an aliphatic group having 1 to 6 carbon atoms.

In the formula (YD-3), W ₂ is a divalent organic group having 6 to 15 carbon atoms and having 1 or 2 benzene rings, and W ₃ is an alkylene group having a carbon number of 2 to 5 or a phenyl group. Z ₂ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a benzene ring, and a is an integer of 0 to 1.

In the formula (YD-4), A ₁₃ is a divalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms.

In the formula (YD-5), A ₁₄ is a divalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms, and W ₅ is an alkylene group having 2 to 5 carbon atoms.

As the nitrogen-containing heterocyclic ring having a carbon number of 3 to 15 of A ₁₁ , A ₁₂ , A ₁₃ , and A ₁₄ of the formulae (YD-1), (YD-2), (YD-4), and (YD-5), If it is a known structure, it is not particularly limited, and examples thereof include pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, hydrazine, benzimidazole, Quinoline, isoquinoline, piperazine, piperidine, hydrazine, benzimidazole, imidazole, oxazole, and pyridine are preferred.

Further, in the formula (1), as a specific example of the divalent organic group having at least one structure selected from the group consisting of an amine group, an imido group and a nitrogen-containing hetero ring, Y ₁ may be exemplified below. a divalent organic group having a nitrogen atom represented by the formula (YD-6) to (YD-23), which has a residual charge when a DC voltage is applied as a liquid crystal display element, and/or a residual charge accumulated by a DC voltage. The idea of easing is also particularly rapid, and the formula (YD-16)~ (YD-23) is particularly good.

In the formula (YD-14), m and n are each an integer of 1 to 11, and m+n is an integer of 2 to 12. In the formula (YD-19), h is an integer from 1 to 3, and in the formulas (YD-16) and (YD-23), j is an integer from 0 to 3.

a polyphthalate having a repeating unit represented by the formula (1), and Y ₁ is a divalent organic compound having at least one selected from the group consisting of an amine group, an imine group, and a nitrogen-containing hetero ring. The ratio of the repeating unit represented by the formula (1) is 1 mol with respect to the total structural unit, preferably 40 to 100 mol%, more preferably 60 to 100 mol%, and particularly preferably 80 to 100. Moer%. Further, the entire structural unit is a structural unit constituting the polyperurethane having a repeating unit represented by the formula (1), and specifically, it is a total of repeating units represented by the formula (1). (mole reference), or a structure other than the repeating unit represented by the formula (1), which is a total of the structures other than the repeating unit represented by the formula (1) and the repeating unit represented by the formula (1) ( Moer benchmark).

In the above formula (1), when Y ₁ is a divalent organic group having a structure selected from at least one selected from the group consisting of an amine group, an imine group and a nitrogen-containing hetero ring, if X ₁ is a tetravalent group The organic group is not particularly limited in its structure, and two or more kinds may be mixed. When a specific example of X ₁ is shown, X-1 to X-46 shown below are mentioned. Among them, from the availability of the raw material monomers, X _{1 is} independently X-1, X-2, X-3, X-4, X-5, X-6, X-8, X-16, X-19, X-21, X-25, X-26, X-27, X-28, X-32, or X-46 are preferred. In order to obtain a liquid crystal alignment film of higher transmittance, X-1, X-2, X-3, X-4, X-5, X-6, X-8, X-16, X having an aliphatic structure -25, or X-46 is better, and X-1, or X-2 is particularly preferred. On the other hand, in order to obtain a liquid crystal alignment film in which the relaxation of the residual electric charge accumulated in the liquid crystal display element by the DC voltage is more rapid, the X-26, X-27, or X-28 having an aromatic structure is more preferable. X-26 or X-32 is especially good.

Further, the polyphthalate used in the repeating unit represented by the formula (1) of the present invention may have a structure other than the repeating unit represented by the formula (1), without impairing the effects of the present invention. . The structure other than the repeating unit represented by the formula (1) includes a repeating unit (structural unit) represented by the following formula (2).

In the formula (2), A ₁ , A ₂ and R _{1 have the} same definitions as in the formula (1), X is a tetravalent organic group, and Y is a divalent organic group.

X, including a suitable example, is the same as X ₁ above.

Y is a divalent organic group, and the structure thereof is not particularly limited, and two or more kinds may be mixed. If specific examples are given, the following formulas Y-1 to Y-100 can be cited.

Among them, in order to obtain good liquid crystal alignment, it is preferred to introduce a poly-maleate having a high linear structure, and as Y, Y-7, Y-21, Y-22, Y-23, Y-25, Y- 26, Y-27, Y-43, Y-44, Y-45, Y-46, Y-48, Y-63, Y-71, Y-73, Y-74, Y-75, Y-98, Y-99, Y-100 is better. Further, in order to increase the pretilt angle, it is preferred to introduce a polyamine amide in a side chain having a long-chain alkyl group, an aromatic ring, an aliphatic ring, a steroid skeleton, or a combination of these structures. ₁ , Y-76, Y-77, Y-78, Y-79, Y-80, Y-81, Y-82, Y-83, Y-84, Y-85, Y-86, Y-87 Y-88, Y-89, Y-90, Y-91, Y-92, Y-93, Y-94, Y-95, Y-96, or Y-97 are more preferred. These structures can exhibit an arbitrary pretilt angle by setting the total amount of the structure derived from the diamine compound from the polyamine product to 1 to 50 mol%. That is, the diamine having such a structure can be found to have an arbitrary pretilt angle by adding 1 to 50 mol% based on the total amount of the diamine compound which is a raw material of the polyphthalate.

The ratio of the structural unit represented by the formula (2) in the polyamine phthalate represented by the formula (1) used in the present invention, in the entire structural unit, that is, relative to the formula (1) The total amount of all structural units composed of the repeating unit polyglycolate represented by 1 mol, preferably 0 to 40 mol%, more preferably 0 to 20 mol%, and particularly preferably 0~ 10 moles %.

<Method for producing polyamidomate>

The polyphthalic acid ester is a tetracarboxylic acid derivative such as tetracarboxylic dianhydride, tetracarboxylic acid diester or dichloride tetracarboxylic acid diester, and a diamine compound (hereinafter also referred to simply as a diamine). It can be synthesized by the methods (1) to (3) shown below. The diamine compound which is a raw material for obtaining a polyperurethane which is a repeating unit represented by the formula (1) is exemplified by the following formula (a1). Further, in order to obtain a polyperurethane having a repeating unit represented by the formula (2), for example, a diamine compound represented by the following formula (a2) can also be used as a raw material. In addition, in order to obtain a tetracarboxylic acid derivative containing a polyperurethane having a repeating unit represented by the formula (1) as a raw material, the following formulas (b1) to (b3) are exemplified. In addition, in order to obtain a polyphthalate having a repeating unit represented by the formula (2), for example, in the following formulas (b1) to (b3), a tetracarboxylic acid derivative in which X ₁ is X may be used as a raw material. (In the formulas (a1) and (a2), A ₁ , A ₂ , Y ₁ and Y are each the same as the formula (1) or the formula (2)).

(in the formulae (b1) to (b3); R ₁ and X ₁ are each the same as in the formula (1)).

(1) When synthesized from polyaminic acid

Polyurethane can be synthesized by esterification of polyamic acid obtained by dicarboxylic acid dianhydride and diamine.

Specifically, the polyamic acid and the esterifying agent obtained by reacting the tetracarboxylic dianhydride with the diamine may be in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C. The reaction is carried out for 30 minutes to 24 hours, preferably 1 to 4 hours.

As the esterifying agent, it may be preferably removed by purification, and examples thereof include N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, and N. , N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentyl butyl acetal, N,N-dimethylformamide di-t-butyl Acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, 4-(4, 6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholine chloride and the like. The amount of the esterifying agent to be added is preferably 1 to 2 moles per mole of the repeating unit of the polyamic acid obtained by the reaction of the tetracarboxylic dianhydride with the diamine.

The solvent used in the above reaction, from the solubility of the polymer (polyglycolic acid or polyglycolate), N,N-dimethylformamide, N-methyl-2-pyrrolidone In addition, γ-butyrolactone may be used, and one type or two or more types may be used in combination. The concentration at the time of the synthesis is preferably from 1 to 30% by mass, more preferably from 5 to 20% by mass, from the viewpoint that the precipitation of the polymer is unlikely to occur and the high molecular weight body is easily obtained.

(2) When the synthesis is carried out by reacting a tetracarboxylic acid diester dichloride with a diamine phase

Polyammonium esters can be synthesized from tetracarboxylic acid diester dichlorides and diamines.

More specifically, by using a tetracarboxylic acid diester dichloride and a diamine The synthesis is carried out in the presence of a base and an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, for 30 minutes to 24 hours, preferably 1 to 4 hours.

Among the above-mentioned bases, pyridine, triethylamine, 4-dimethylaminopyridine or the like can be used, and in order to carry out the reaction gently, pyridinium is preferred. The amount of the base to be added is preferably 2 to 4 moles per mole of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal amount and easy availability of a high molecular weight body.

The solvent of the above reaction is N-methyl-2- from the viewpoint of solubility of a raw material monomer (tetracarboxylic acid derivative or diamine compound) and a polymer (polyglycolic acid or polyglycolate). Pyrrolidone and γ-butyrolactone are preferred, and one type or two or more types may be used in combination. From the viewpoint of not easily forming a polymer and easily obtaining a high molecular weight body, it is preferably 1 to 30% by mass, more preferably 5 to 20% by mass.

Further, in order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, it is preferred to dehydrate the solvent used in the synthesis of the polyglycolate as much as possible, and to prevent the intrusion of outside air in a nitrogen atmosphere.

(3) When synthesizing from a tetracarboxylic acid diester and a diamine

Polyammonium esters can be synthesized by polycondensation of a tetracarboxylic acid diester with a diamine.

Specifically, the reaction can be carried out for 30 minutes to 24 hours by using a tetracarboxylic dianhydride and a diamine in the presence of a condensing agent, a base or an organic solvent at 0 ° C to 150 ° C, preferably 0 ° C to 100 ° C. Preferably, the synthesis is carried out for 3 to 15 hours.

Among the above condensing agents, triphenyl phosphate, dicyclohexyl carbon can be used. Dimethyleneimine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, dimethoxy-1,3, 5-triazinylmethylmorpholine, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethylurea cation (uronium) tetrafluoroborate, O-( Benzotriazol-1-yl)-N,N,N',N'-tetramethylurea cation (uronium) hexafluorophosphate, (2,3-dihydroxy-2-thio (Thioxo)-3 - benzomethoxazole) sulfonic acid diphenyl or the like. The amount of the condensing agent added is preferably 2 to 3 moles per mole of the tetracarboxylic acid diester.

Among the above bases, a tertiary amine such as pyridine or triethylamine can be used. The amount of the base to be added is preferably from 2 to 4 times the molar amount of the diamine compound from the viewpoint of easily removing the amount and easily obtaining a high molecular weight body.

Further, in the above reaction, Lewis acid is added as an additive to carry out the reaction efficiently. As the Lewis acid, lithium halide such as lithium chloride or lithium bromide is preferred. The addition amount of Lewis acid is preferably 0 to 1.0 times the molar amount of the diamine compound.

In the method for synthesizing the above three polyglycolates, in order to obtain a high molecular weight polyglycolate, the synthesis method of the above (1) or (2) is particularly preferable.

The polyphthalate solution obtained as described above is sufficiently stirred and injected into a poor solvent to precipitate a polymer (polyglycolate). The precipitation is carried out several times, washed with a poor solvent, and then purified at room temperature or by heating to obtain a polyphthalate powder. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, and the like.

a polyamine phthalate having a repeating unit represented by the formula (1) The average molecular weight is preferably 5,000 to 300,000, more preferably 10,000 to 200,000. Further, the number average molecular weight thereof is preferably from 2,500 to 150,000, more preferably from 5,000 to 100,000.

<Liquid alignment agent>

The liquid crystal alignment agent of the present invention contains a polyphthalate having a repeating unit represented by the above formula (1) and an organic solvent. Thus, the liquid crystal alignment film obtained from the liquid crystal alignment agent containing the polyamine phthalate having the repeating unit represented by the formula (1) has a high transmittance and is provided by a liquid crystal display element having the liquid crystal alignment film. The residual charge accumulated by the voltage is quickly relaxed.

It is not necessarily clear that the problem of the present invention can be solved by using a liquid crystal alignment agent containing a polyphthalate having a repeating unit represented by the formula (1), and it is almost as follows.

In general, a ruthenium imidized polymer (polyimine) has a higher imidization ratio, a longer absorption wavelength, and a film obtained by firing a liquid crystal alignment agent (liquid crystal alignment film). Coloring.

In contrast, the polyphthalate ester of the repeating unit represented by the formula (1) contained in the liquid crystal alignment agent of the present invention is presumably because it is difficult to carry out the imidization by heating (firing). By reducing the coloration by ruthenium imidation, a liquid crystal alignment film having a high transmittance can be obtained.

Further, as a result of investigation by the present inventors, a compound having an amine group, an imido group, and a nitrogen-containing hetero ring has been known, and a nitrogen atom in the compound is oxidized by the influence of oxygen or water in the air to be colored.

Therefore, polylysine or a part of polylysine is ytterbium-imided with a liquid crystal alignment agent containing soluble polyimine because of high polarity in the polymer (polyproline or polyimine) The carboxyl group has a strong interaction with water, and it is expected that water molecules in the polymer will be included. Further, in the above polymer, when it is imidized by heating, a water as a leaving group is formed. It is considered that the nitrogen atom contained in the structure having an amine group, an imine group, and a nitrogen-containing hetero ring is oxidized by the water, and the transmittance of the obtained film is lowered.

In contrast, the liquid crystal alignment agent of the present invention contains an ester group in a repeating unit of a polyphthalate represented by the formula (1), which is less polar than a carboxyl group and does not easily incorporate water molecules. Construction. Further, in the case of a polyphthalamide, when it is imidized by heating, an alcohol as a leaving group is produced. For this reason, it is considered that a nitrogen atom contained in a structure having an amine group, an imine group, and a nitrogen-containing hetero ring is reduced in oxidation by water to obtain a liquid crystal alignment film having a high transmittance.

Further, the liquid crystal alignment agent of the present invention is considered to have a liquid crystal obtained by a repeating unit represented by the formula (1) having an amine group, an imide group and a nitrogen-containing hetero ring. As a liquid crystal display element of the alignment film, it was found that the relaxation of the residual charge accumulated by the DC voltage can be made rapid.

From the above, the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is considered to be a liquid crystal display element having a high transmittance and having the liquid crystal alignment film, and the residual charge accumulated by the DC voltage can be alleviated. rapid.

Further, Patent Document 1 discloses a liquid crystal alignment agent containing a polyamido acid containing a quinone imine group, and the quinone imine-containing polyaminic acid of Patent Document 1 is not a repeating unit represented by the above formula (1). In the case of Y ₁ or X ₁ having a quinone imine group, of course, Patent Document 1 does not describe the polyphthalate. Further, Patent Document 2 describes a liquid crystal alignment agent containing a ruthenium imidized polymer having a divalent organic group structure having a nitrogen atom such as a pyridine ring (that is, polyimine), and Patent Document 2 Polyurethane esters are not described at all. In the liquid crystal alignment agent of Patent Document 1 or Patent Document 2, the high transmittance of the liquid crystal display element having the liquid crystal alignment film and the residual charge accumulated by the DC voltage of the liquid crystal display element having the liquid crystal display film can be quickly obtained.

The liquid crystal alignment agent of the present invention is in the form of a solution in which a polyamine phthalate having a repeating unit represented by the above formula (1) is dissolved in an organic solvent. When such a form is used, for example, when the polyglycolate is synthesized in an organic solvent, it may be the obtained reaction solution itself, and the reaction solution may be obtained by diluting it in a suitable solvent. Further, when the polyglycolate is obtained as a powder, it may be dissolved in an organic solvent to obtain a solution.

The content (concentration) of the polyphthalate (hereinafter also referred to as polymer) of the liquid crystal alignment agent of the present invention can be appropriately changed by setting the thickness of the liquid crystal alignment film formed, but a uniform and defect-free coating film is formed. In this case, the content of the polymer component is preferably 0.5% by mass or more, and preferably 15% by mass or less, more preferably 1% to 10% by mass, from the viewpoint of storage stability of the solution. Further, at this time, a thick solution of the polymer is prepared in advance, and it may be diluted from such a thick solution to a liquid crystal alignment agent. The concentration of the thick solution of the polymer component is 10 to 30% by mass. Good, preferably 10~15% by mass. Further, when the powder of the polymer component is dissolved in an organic solvent to prepare a solution, it may be heated. The heating temperature is preferably from 20 ° C to 150 ° C, and particularly preferably from 20 ° C to 80 ° C. Further, a polymer component which is a polyperurethane ester having a repeating unit represented by the formula (1) or, if necessary, a polyphthalate ester having no repeating unit represented by the formula (1), Polymers other than polyamphanes.

The organic solvent contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as the polymer component can be uniformly dissolved. Specific examples thereof include N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. , N-ethyl-2-pyrrolidone, N-methyl caprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl hydrazine, dimethyl hydrazine, γ - Butyrolactone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N,N-dimethylpropionamide, and the like. These may be used alone or in combination of two or more. Moreover, even if it is a solvent which cannot melt|dissolve a polymer component uniformly, it can mix with the above-mentioned organic solvent in the range which does not isolate a polymer.

The liquid crystal alignment agent of the present invention may contain a solvent for improving the uniformity of the coating film when the liquid crystal alignment agent is applied to the substrate, in addition to the organic solvent for dissolving the polymer component. As such a solvent, a solvent having a lower surface tension than the above organic solvent is generally used. Specific examples thereof include ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methyl Oxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diethyl Acid ester, propylene glycol-1-monomethyl ether-2- Acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate , n-butyl lactate, isoamyl lactate and the like. These solvents may be used in combination of two or more kinds.

In the liquid crystal alignment agent of the present invention, in addition to the above, the polymer other than the polyamine phthalate having the repeating unit represented by the formula (1) is specifically added to the formula without impairing the effects of the present invention. (1) a polymer or a conductive material for the purpose of changing the electrical properties such as the electric conductivity or conductivity of the liquid crystal alignment film by a polyamine or a polymer other than the polyamine derivative represented by the repeating unit. A cyclane coupling agent for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, and a bridging compound for the purpose of improving the hardness or density of the film when the liquid crystal alignment film is formed may be used.

<Liquid alignment film>

The liquid crystal alignment film of the present invention is a film obtained by applying the liquid crystal alignment agent onto a substrate and, if necessary, drying and baking. The substrate to which the liquid crystal alignment agent of the present invention is applied is not particularly limited, and a substrate such as a glass substrate, a tantalum nitride substrate, an acrylic substrate, or a polycarbonate substrate can be used. A substrate such as an ITO (Indium Tin Oxide) electrode driven by a liquid crystal is preferable from the viewpoint of simplification of the process. Further, in the reflective liquid crystal display device, only one of the substrate, the wafer, or the like can be used as an opaque material. In this case, a material that reflects light such as aluminum can be used as the electrode.

As a coating method of the liquid crystal alignment agent of the present invention, a spin coating method, Printing method, inkjet method, and the like. The drying and baking steps of the liquid crystal alignment agent of the present invention after coating can be selected to any temperature and time. Usually, in order to completely remove the organic solvent contained, it is dried at 50 ° C to 120 ° C for 1 minute to 10 minutes, and then fired at 150 ° C to 300 ° C for 5 minutes to 120 minutes. Still, the drying step may not be performed. The thickness of the coating film after firing is not particularly limited. However, if it is too thin, the reliability of the liquid crystal display element may be lowered, so that it is 5 to 300 nm, preferably 10 to 200 nm.

Examples of the alignment treatment method of the obtained liquid crystal alignment film include a rubbing method, a photo alignment treatment method, and the like. Further, in the present invention, the alignment treatment may not be performed.

Specific examples of the photo-alignment treatment method include a method in which radiation on a surface of the coating film is irradiated in a certain direction, and heat treatment is performed at a temperature of 150 to 250 ° C as appropriate to impart alignment energy to the liquid crystal. As the radiation, ultraviolet rays and visible light having a wavelength of 100 nm to 800 nm can be used. Among them, ultraviolet rays having a wavelength of 100 nm to 400 nm are preferred, and those having a wavelength of 200 nm to 400 nm are particularly preferred. Further, in order to improve the liquid crystal alignment property, the coated substrate may be heated at 50 to 250 ° C while irradiating radiation. The irradiation amount of radiation to 1 ~ 10,000mJ / cm ² preferably, to 100 ~ 5,000mJ / cm ² is particularly preferred. Like the liquid crystal alignment film produced as described above, the liquid crystal molecules can be stabilized to face in a certain direction.

<Liquid crystal display element>

The liquid crystal display element of the present invention is the present invention by the above method The liquid crystal alignment agent obtains a substrate to which a liquid crystal alignment film is attached, and if necessary, an alignment treatment is performed, and a liquid crystal cell is formed by a generally known method to obtain a liquid crystal display element.

The method for producing the liquid crystal cell is not particularly limited. For example, a pair of substrates on which a liquid crystal alignment film is formed may be used, and the liquid crystal alignment film surface faces inward, and the intermediate layer is preferably 1 to 30 μm, more preferably 2 to 10 μm. After the spacer, the periphery is fixed with a sealant, and liquid crystal is injected to seal it into a common method. The method of encapsulating the liquid crystal is not particularly limited, and examples thereof include a vacuum method in which a liquid crystal cell is injected under reduced pressure, a dropping method in which liquid crystal is dropped, and sealing is performed.

[Examples]

The invention is illustrated in more detail below by way of examples, and the invention is not limited thereto. The method of measuring the abbreviations of the compounds used in the examples and the comparative examples and the respective characteristics are as follows.

DE-1: the following formula (DE-1)

DE-2: the following formula (DE-2)

DE-3: the following formula (DE-3)

DA-1: the following formula (DA-1)

DA-2: the following formula (DA-2)

DA-3: the following formula (DA-3)

NMP: N-methyl-2-pyrrolidone

BCS: butyl cellosolve

GBL: γ-butyrolactone

(wherein Me represents a methyl group).

(wherein Me represents a methyl group).

[viscosity]

In the synthesis example and the comparative synthesis example, the viscosity of the polyphthalate and the poly-proline solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample volume of 1.1 mL, and a cone rotor (Cone rotor). TE-1 (1° 34', R24) was measured at a temperature of 25 °C.

[molecular weight]

Further, the molecular weight of the polyglycolate is measured by a GPC (normal temperature gel permeation chromatography) apparatus, and the number average molecular weight (hereinafter also referred to as Mn) is calculated using polyethylene glycol or polyethylene oxide as a conversion value. Weight average molecular weight (hereinafter also referred to as Mw).

GPC device: manufactured by Shodex (GPC-101)

Pipe column: made by Shodex company (inline of KD803, KD805)

Column temperature: 50 ° C

Eluent: N,N-dimethylformamide (as additive, lithium bromide-water and (LiBr.H ₂ O) 30 mmol/L, phosphoric acid. anhydrous crystal (o-phosphoric acid) 30 mmol/L, tetrahydrofuran (THF) ) 10ml / L)

Flow rate: 1.0ml/min

Standard sample for calibration line preparation: TSK standard polyethylene oxide (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Co., Ltd., and polyethylene glycol (manufactured by Polymer Laboratory) (Mp) approximately 12,000, 4,000, 1,000). Measurements In order to avoid peak repetitive, four mixed samples of 900,000, 100,000, 12,000, and 1,000, and three mixed samples of 150,000, 30,000, and 4,000 were each measured in two samples.

(Synthesis Example 1)

DE-2 3.39 g (13.0 mmol) and DE-3 1.69 g (5.99 mmol) were added to a 200 ml four-necked flask equipped with a stirring device, and NMP was added. 84.69 g, stirred to dissolve. Next, 4.45 g (44.0 mmol) of triethylamine and 3.99 g (20.0 mmol) of 4,4'-diaminodiphenylamine were added, and the mixture was stirred and dissolved. This solution was stirred while adding 16.87 g (44.0 mmol) of diphenyl (2,3-dihydroxy-2-thio (Thioxo)-3-benzazole) sulfonic acid, followed by addition of 11.63 g of NMP, and water-cooled. The reaction was allowed to proceed for 4 hours. The obtained polyglycolate solution was charged with 760 g of 2-propanol while stirring, and the deposited precipitate was collected by filtration, and then washed with 253 g of 2-propanol for 5 times to obtain a polyamidate. Resin powder. The molecular weight of this polyphthalate was Mn = 13646 and Mw = 28,242.

1.78 g of the obtained polyphthalate resin powder was placed in a 50 ml Erlenmeyer flask, 16.02 g of NMP was added, and the mixture was stirred at room temperature for 24 hours to be dissolved to obtain a polyamidate solution (PAE-1).

(Synthesis Example 2)

DE 2 3.39 g (13.0 mmol) and DE-3 1.69 g (5.99 mmol) were placed in a 200 ml four-necked flask equipped with a stirring apparatus, and 84.53 g of NMP was added thereto, and the mixture was stirred and dissolved. Next, 4.45 g (44.0 mmol) of triethylamine and 4.26 g (20.0 mmol) of DA-1 were added, and the mixture was stirred and dissolved. This solution was stirred while adding 16.87 g (44.0 mmol) of diphenyl (2,3-dihydroxy-2-thio (Thioxo)-3-benzazole) sulfonic acid, followed by addition of 12.02 g of NMP, and water-cooled. The reaction was allowed to proceed for 4 hours. The obtained polyglycolate solution was charged with 781 g of 2-propanol while stirring, and the precipitate was collected by filtration, and then washed with 260 g of 2-propanol for 5 times to obtain a polyamidate. Resin powder. This gathering The molecular weight of the amine ester was Mn = 10,326 and Mw = 21,332.

2.10 g of the obtained polyphthalate resin powder was placed in a 50 ml Erlenmeyer flask, and 18.98 g of NMP was added thereto, and the mixture was stirred at room temperature for 24 hours to be dissolved to obtain a polyamidate solution (PAE-2).

(Synthesis Example 3)

DE-2 1.69 g (6.50 mmol) and DE-3 0.85 g (3.00 mmol) were placed in a 200 ml four-necked flask equipped with a stirring apparatus, and 61.89 g of NMP was added thereto, and the mixture was stirred and dissolved. Next, 2.23 g (22.0 mmol) of triethylamine and 3.92 g (9.99 mmol) of DA-3 were added, and the mixture was stirred and dissolved. This solution was added with 8.43 g (22.0 mmol) of (2,3-dihydroxy-2-thio(Thioxo)-3-benzhydroxazole)sulfonic acid diphenyl while stirring, and then added 8.50 g of NMP in water-cooled. The reaction was allowed to proceed for 4 hours. The obtained polyglycolate solution was charged with 525 g of 2-propanol while stirring, and the deposited precipitate was collected by filtration, and then washed with 175 g of 2-propanol for 5 times to obtain a polyamidate. Resin powder. The molecular weight of this polyphthalate was Mn=22044 and Mw=56569.

2.11 g of the obtained polyphthalate resin powder was placed in a 50 ml Erlenmeyer flask, and 18.99 g of NMP was added thereto, and the mixture was stirred at room temperature for 24 hours to be dissolved to obtain a polyamine ester solution (PAE-3).

(Synthesis Example 4)

Additional stirring apparatus 300 ml four-necked flask was filled with nitrogen, and placed into DA-2 3.02 g (11.3 mmol), NMP 108 g, and added as a base pyridine. 1.99 g (25.2 mmol) was stirred and dissolved. Next, 3.38 g (10.5 mmol) of DE-1 was added to the diamine solution while stirring, and the mixture was reacted for 4 hours under water cooling. The obtained polyglycolate solution was charged with 468 g of 2-propanol while stirring, and the deposited precipitate was collected by filtration, and then washed with 234 g of 2-propanol for 5 times to obtain polylysine. Ester resin powder. The molecular weight of this polyphthalate was Mn = 16548 and Mw = 37,836.

1.79 g of the obtained polyphthalate resin powder was placed in a 50 ml Erlenmeyer flask, and 16.11 g of NMP was added thereto, and the mixture was stirred at room temperature for 24 hours to be dissolved to obtain a polyamine ester solution (PAE-4).

(Synthesis Example 5)

Additional stirring apparatus 300 ml four-necked flask was filled with nitrogen, and 2.02 g (10.1 mmol) of 4,4'-diaminodiphenylamine and 1.02 g (6.70 mmol) of 3,5-diaminobenzoic acid were added and added. 135 g of NMP and 2.99 g (37.7 mmol) of pyridine as a base were stirred and dissolved. Next, the diamine solution was stirred while adding 5.14 g (15.8 mmol) of DE-1, and the mixture was reacted under water cooling for 4 hours. The obtained polyglycolate solution was charged with 584 g of 2-propanol while stirring, and the deposited precipitate was collected by filtration, and then washed with 292 g of 2-propanol for 5 times to obtain polylysine. Ester resin powder. The molecular weight of this polyphthalate was Mn = 9724 and Mw = 19,380.

3.56 g of the obtained polyphthalate resin powder was placed in a 50 ml Erlenmeyer flask, and 32.09 g of NMP was added thereto, and the mixture was stirred at room temperature for 24 hours. Dissolved to obtain a polyamidate solution (PAE-5).

(Comparative Synthesis Example 1)

Into a 100 ml four-necked flask equipped with a stirring apparatus and a nitrogen introducing tube, 3.99 g (20.0 mmol) of 4,4'-diaminodiphenylamine was added, and 63.9 g of NMP was added thereto, and the mixture was stirred and dissolved while supplying nitrogen gas. To the diamine solution, 2.63 g (13.4 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1.30 g (5.96 mmol) of pyromellitic dianhydride were added while stirring, and further, solid content was obtained. NMP was added in such a manner that the content concentration became 10% by mass, and the mixture was stirred at room temperature for 24 hours to obtain a polyaminic acid solution (PAA-1). The obtained polyaminic acid solution has a viscosity of 881 mPa at a temperature of 25 ° C. s. Further, the molecular weight of the polyamic acid was Mn = 16766 and Mw = 59,104.

(Comparative Synthesis Example 2)

To a 100 ml four-necked flask equipped with a stirring apparatus and a nitrogen inlet tube, 4.27 g (20.0 mmol) of DA-1 was added, and 66.4 g of NMP was added thereto, and the mixture was stirred and dissolved while supplying nitrogen gas. To the diamine solution, 2.63 g (13.4 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1.30 g (5.96 mmol) of pyromellitic dianhydride were added while stirring, and further, solid content was obtained. NMP was added in such a manner that the content concentration became 10% by mass, and the mixture was stirred at room temperature for 24 hours to obtain a polyaminic acid solution (PAA-2). The obtained polyaminic acid solution has a viscosity of 153 mPa at a temperature of 25 ° C. s. Further, the molecular weight of the polyamic acid was Mn = 13227 and Mw = 38,432.

(Comparative Synthesis Example 3)

To a 100 ml four-necked flask equipped with a stirring apparatus and a nitrogen introducing tube, DA-3 3.15 g (8.02 mmol) was added, and 37.6 g of NMP was added thereto, and the mixture was stirred and dissolved while supplying nitrogen gas. To the diamine solution, 0.972 g (4.96 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 0.526 g (2.41 mmol) of pyromellitic dianhydride were added while stirring, and further solid content was obtained. NMP was added in such a manner that the content concentration became 10% by mass, and the mixture was stirred at room temperature for 24 hours to obtain a polyaminic acid solution (PAA-3). The obtained polyaminic acid solution has a viscosity of 2045 mPa at a temperature of 25 ° C. s. Further, the molecular weight of the polyamic acid was Mn = 16418 and Mw = 56595.

(Example 1)

A stirrer was placed in a 50 ml Erlenmeyer flask, and 5.52 g of the polyamidate solution (PAE-1) obtained in Synthesis Example 1 was added, and 3.45 g of NMP and 2.22 g of BCS were added, and the mixture was stirred under a magnetic stirrer for 30 minutes. Liquid crystal alignment agent (A-1).

(Example 2)

A stirrer was placed in a 50 ml Erlenmeyer flask, and 5.12 g of a polyamidomate solution (PAE-2) obtained in Synthesis Example 2 was added, and NMP 3.08 g and BCS 2.07 g were added, and the mixture was stirred under a magnetic stirrer for 30 minutes. Liquid crystal alignment agent (A-2).

(Example 3)

The stirrer was placed in a 50 ml Erlenmeyer flask, and 4.04 g of the polyamidate solution (PAE-3) obtained in Synthesis Example 3 was added, and NMP 4.08 g and BCS 2.03 g were added, and the mixture was stirred under a magnetic stirrer for 30 minutes. Liquid crystal alignment agent (A-3).

(Example 4)

A stirrer was placed in a 50 ml Erlenmeyer flask, 4.99 g of a polyamidomate solution (PAE-4) obtained in Synthesis Example 4 was added, and NMP 3.00 g and BCS 2.02 g were added, and the mixture was stirred under a magnetic stirrer for 30 minutes. Liquid crystal alignment agent (A-4).

(Example 5)

A stirrer was placed in a 50 ml Erlenmeyer flask, and 5.33 g of a polyamidomate solution (PAE-5) obtained in Synthesis Example 5 was added, and 3.26 g of NMP and 2.30 g of BCS were added, and stirred under a magnetic stirrer for 30 minutes. Liquid crystal alignment agent (A-5).

(Comparative Example 1)

A stirrer was placed in a 50 ml Erlenmeyer flask, and 4.87 g of the polyaminic acid solution (PAA-1) obtained in Comparative Synthesis Example 1 was added, and 2.97 g of NMP and 1.98 g of BCS were added, and stirred under a magnetic stirrer for 30 minutes. Liquid crystal alignment agent (B-1).

(Comparative Example 2)

A stirrer was placed in a 50 ml Erlenmeyer flask, and 5.22 g of the polyamidonic acid solution (PAA-2) obtained in Comparative Synthesis Example 2 was added, and 3.15 g of NMP and 2.18 g of BCS were added, and the mixture was stirred under a magnetic stirrer for 30 minutes. Liquid crystal alignment agent (B-2).

(Comparative Example 3)

A stirrer was placed in a 50 ml Erlenmeyer flask, and 4.37 g of the polyamidonic acid solution (PAA-3) obtained in Comparative Synthesis Example 3 was added, and 4.38 g of NMP and 2.21 g of BCS were added, and the mixture was stirred under a magnetic stirrer for 30 minutes to obtain Liquid crystal alignment agent (B-3).

(Example 6)

The liquid crystal alignment agent (A-1) obtained in Example 1 was filtered in a 1.0 μm filter, coated on a quartz substrate by spin coating, and dried on a hot plate at 80 ° C. 5 After a minute, the film was fired in a hot air circulating oven at 230 ° C for 30 minutes to form a coating film having a film thickness of 100 nm. The transmittance of the obtained coating film was measured using an ultraviolet-visible spectrophotometer (UV-3100PC) manufactured by Shimadzu Corporation, and the average value of the transmittance of 360 nm to 800 nm was calculated. As a result, the transmittance of the obtained film was 95.14%. The calculated transmittance is shown in Table 1.

(Example 7)

The transmittance of the film was measured in the same manner as in Example 6 except that the liquid crystal alignment agent (A-2) obtained in Example 2 was used. Obtained The transparency of the film was 93.35%.

(Example 8)

The transmittance of the film was measured in the same manner as in Example 6 except that the liquid crystal alignment agent (A-3) obtained in Example 3 was used. The transmittance of the obtained film was 92.74%.

(Example 9)

The transmittance of the film was measured in the same manner as in Example 6 except that the liquid crystal alignment agent (A-4) obtained in Example 4 was used. The transmittance of the obtained film was 96.17%.

(Embodiment 10)

The transmittance of the film was measured in the same manner as in Example 6 except that the liquid crystal alignment agent (A-5) obtained in Example 5 was used. The transmittance of the obtained film was 95.35%.

(Comparative Example 4)

The transmittance of the film was measured in the same manner as in Example 6 except that the liquid crystal alignment agent (B-1) obtained in Comparative Example 1 was used. The transmittance of the obtained film was 89.58%.

(Comparative Example 5)

In addition to the liquid crystal alignment agent (B-2) obtained in Comparative Example 2, Further, the transmittance of the film was measured in the same manner as in Example 6. The transmittance of the obtained film was 91.35%.

(Comparative Example 6)

The transmittance of the film was measured in the same manner as in Example 6 except that the liquid crystal alignment agent (B-3) obtained in Comparative Example 3 was used. The transmittance of the obtained film was 88.56%.

(Example 11)

The liquid crystal alignment agent (A-1) obtained in Example 1 was filtered through a 1.0 μm filter, and then an ITO electrode having a film thickness of 50 nm in the first layer was formed on the glass substrate, and the film thickness of the second layer was 500 nm as an insulating film. In the third layer, the driving electrode of FFS (Fringe Field Switching) having an ITO electrode (electrode width: 3 μm, electrode spacing: 6 μm, electrode height: 50 nm) having a serrated shape is formed on the glass substrate. The coating was carried out by spin coating. After drying on a hot plate at 80 ° C for 5 minutes, it was baked in a hot air circulating oven at 230 ° C for 30 minutes to form a coating film having a film thickness of 100 nm. On the surface of the coating film, the number of rolls is rotated by 1000 rpm, the stage A rubbing treatment was carried out under the conditions of a moving speed of 20 mm/s and a rubbing cloth pushing pressure of 0.4 mm to obtain a substrate with a liquid crystal alignment film. Further, a glass film having a columnar pitch of 4 μm in height which does not form an electrode on the opposite substrate was formed into a coating film, and an alignment treatment was performed.

The two substrates are grouped together, and the substrate is printed with a sealant, and the other substrate can be made 0° in the direction of alignment of the liquid crystal alignment film surface to be bonded, and then the sealant is cured to form an empty cell. This empty cell was injected into a liquid crystal MLC-2041 (manufactured by Merck & Co., Inc.) by a vacuum injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. With respect to this FFS-driven liquid crystal cell, the charge relaxation characteristics were evaluated by the following method. The ΔT of the AC drive for 0 minutes was 47%, and the ΔT of the AC drive for 5 minutes was 0%.

[Charge mitigation characteristics]

The FFS-driven liquid crystal cell was placed on a light source, and after measuring the VT characteristic (voltage-transmittance characteristic) at a temperature of 45 ° C, the transmittance of the rectangular wave of ±1.5 V/60 Hz in the liquid crystal cell of the applied state was measured. (Ta). Thereafter, a rectangular wave of ±1.5 V/60 Hz was applied at a temperature of 45 ° C for 10 minutes, and then driven by a DC of 2 V for 120 minutes. Cut off the DC voltage, and then measure the transmittance (Tb) of the liquid crystal cell when driving with a rectangular wave of only ±1.5V/60Hz at 0 minutes and 5 minutes, and the transmittance (Tb) from each time. The initial transmittance (Ta) difference (ΔT) is calculated as the difference in transmittance due to the voltage remaining in the liquid crystal display element.

(Embodiment 12)

An FFS-driven liquid crystal cell was produced in the same manner as in Example 11 except that the liquid crystal alignment agent (A-2) obtained in Example 2 was used, and the charge relaxation property was evaluated. The ΔT of the AC drive at 0 minutes was 46%. The ΔT of the AC drive for 5 minutes is 0%.

(Example 13)

An FFS-driven liquid crystal cell was produced in the same manner as in Example 11 except that the liquid crystal alignment agent (A-3) obtained in Example 3 was used, and the charge relaxation property was evaluated. The ΔT of the AC drive at 0 minutes was 46%. The ΔT of the AC drive for 5 minutes is 0%.

(Example 14)

In the same manner as in Example 11, except that the liquid crystal alignment agent (A-4) obtained in Example 4 was used, an FFS-driven liquid crystal cell was produced, and as a result of evaluating the charge relaxation characteristics, the ΔT of the AC drive at 0 minutes was 46%, ΔT of AC drive for 5 minutes is 0%.

(Example 15)

An FFS-driven liquid crystal cell was produced in the same manner as in Example 11 except that the liquid crystal alignment agent (A-5) obtained in Example 5 was used, and the charge relaxation property was evaluated. The ΔT of the AC drive at 0 minutes was 46%. The ΔT of the AC drive for 5 minutes is 0%.

(Comparative Example 7)

An FFS-driven liquid crystal cell was produced in the same manner as in Example 11 except that the liquid crystal alignment agent (B-1) obtained in Comparative Example 1 was used. The same charge-relieving property as in Example 11 was evaluated in the FFS-driven liquid crystal cell. As a result, the ΔT of the AC drive at 46 minutes was 46%, and the ΔT of the AC drive for 5 minutes was 0%.

In this manner, the liquid crystal alignment films of Examples 6 to 10 obtained from the liquid crystal alignment agents A-1 to A-5 containing the polyphthalate having the repeating unit represented by the formula (1), and Comparative Example 4 Compared with the liquid crystal alignment film of ~6, the transmittance is significantly higher. Further, the liquid crystal display element including the liquid crystal alignment film obtained from the liquid crystal alignment agents A-1 to A-5 has a faster relaxation of the residual electric charge accumulated by the DC voltage.

[Industrial Applicability]

The liquid crystal alignment agent of the present invention has a characteristic that a small amount of residual electric charge when a direct current voltage is applied, and/or a rapid relaxation of residual electric charge accumulated by a direct current voltage, and a liquid crystal alignment film having a high transmittance of the obtained film is obtained. As a result, it is widely used for TN (Twisted Nematic) elements, STN (Super Twisted Nematic) elements, TFT liquid crystal elements, and more vertical alignment type liquid crystal display elements.

Claims (9)

A liquid crystal alignment agent characterized by comprising a polyphthalate having a repeating unit represented by the following formula (1) and an organic solvent, (In the formula (1), X ₁ is a tetravalent organic group, Y ₁ is a divalent organic group, and at least one of X ₁ and Y ₁ contains an amine group, an imido group, and a nitrogen-containing heterocyclic ring. a structure of at least one selected from the group consisting of R ₁ being an alkyl group having 1 to 5 carbon atoms, and each of A ₁ and A _{2 being} independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent Base, alkenyl or alkynyl). The liquid crystal alignment agent of the first aspect of the invention, wherein Y ₁ in the formula (1) is a valence of at least one selected from the group consisting of an amine group, an imine group and a nitrogen-containing hetero ring. Organic base. The liquid crystal alignment agent of the first aspect of the invention, wherein Y ₁ is a divalent organic group having at least one structure selected from the group consisting of an amine group, an imine group and a nitrogen-containing hetero ring; (1) The proportion of repeating units represented is 40 to 100 mol% relative to the total structural unit of 1 mol. The liquid crystal alignment agent of claim 1, wherein Y ₁ is at least selected from the group consisting of a divalent organic group having a nitrogen atom represented by the following formula (YD-1) to (YD-5); 1 species, (In the formula (YD-1), A ₁₁ is a trivalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms, and Z ₁ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; In the formula (YD-2), W ₁ is a trivalent hydrocarbon group having 1 to 10 carbon atoms, A ₁₂ is a monovalent organic group having a carbon number of 3 to 15 having a nitrogen-containing hetero ring, or 2 hydrogens of an amine group are each independently a disubstituted amino group substituted with an aliphatic group having 1 to 6 carbon atoms; in the formula (YD-3), W ₂ is a carbon number of 6 to 15, and has a valence of 1 or 2 benzene rings. The organic group, W ₃ is an alkylene group having a carbon number of 2 to 5 or a phenyl group, Z ₂ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a benzene ring, and a is an integer of 0 to 1; In (YD-4), A ₁₃ is a divalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms; in the formula (YD-5), A ₁₄ is a divalent nitrogen-containing heterocyclic ring having 3 to 15 carbon atoms, W ₅ It is an alkyl group having a carbon number of 2 to 5). The liquid crystal alignment agent of the first aspect of the patent application, wherein A ₁ , A ₂ , and A ₃ described in the formulas (YD-1), (YD-2), (YD-4), and (YD-5) And a nitrogen-containing heterocyclic ring having a carbon number of 3 to 15 of A ₄ , which is pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, hydrazine, benzimidazole, A ring of at least one selected from the group consisting of quinoline and isoquinoline. The liquid crystal alignment agent of claim 1, wherein Y ₁ in the formula (1) is a divalent organic compound having a nitrogen atom represented by the following formula (YD-6) to (YD-23); Select at least one of the group of foundations, (In the formula (YD-14), m and n are each an integer from 1 to 11, m+n is an integer from 2 to 12, and in the formula (YD-19), h is an integer from 1 to 3, and the formula (YD- In 16) and (YD-23), j is an integer from 0 to 3. The liquid crystal alignment agent of the first aspect of the invention, wherein X ₁ in the formula (1) is at least one selected from the group consisting of structures represented by the following formulas, A liquid crystal alignment film which is obtained by coating and firing a liquid crystal alignment agent according to any one of claims 1 to 7. A liquid crystal display element characterized by having a liquid crystal alignment film according to item 8 of the patent application.