TWI668247B - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal alignment element using the same - Google Patents

Abstract

Provided is a liquid crystal alignment agent which can produce a liquid crystal alignment film having a high voltage holding ratio even when a backlight is irradiated for a long period of time or impurities are mixed in a liquid crystal.

A liquid crystal alignment agent comprising a polyphthalate having a repeating unit of the formula (1) and an organic solvent.

(X ₁ is a tetravalent organic group, Y ₁ is a divalent organic group, R is an alkyl group having 1 to 5 carbon atoms, A ₁ and A ₂ are a hydrogen atom, or a carbon number of 1 to 10 which may have a substituent An alkyl, alkenyl or alkynyl group, at least a part of Y _{1 being} a divalent organic group of the formula (2).

(D represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, and D may have a substituent. Further, m is 1 or 0).

Description

Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element using the same

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.

The liquid crystal display device has been widely used as a display unit for computers, mobile phones, television projectors, and the like, and has been known as a vertical electric field method such as a TN method or a VA method, or an IPS method or an FFS method (Fringe). Field Switching) and other transverse electric field methods.

In general, an electrode is formed only on one side of a substrate, and a transverse electric field method in which an electric field is applied in parallel with the substrate is compared with a conventional method of applying a voltage to an electrode formed on the upper and lower substrates to drive a liquid crystal. It is known as a liquid crystal display element having a wide viewing angle characteristic and having high quality display. A method of aligning liquid crystals in a certain direction is known in which a polymer film such as polyimide is formed on a substrate, and the surface is wiped with a cloth, that is, a method of rubbing treatment, and is widely used industrially.

Problems that have been solved in the past, such as voltage retention, or Charge accumulation caused by a DC voltage component applied by an active matrix structure. When the electric charge is accumulated in the liquid crystal display element, the alignment of the liquid crystal is disturbed, or the display content is affected by the afterimage, and the display quality of the liquid crystal display element is remarkably lowered. Or, in the case of driving in the state of accumulating charge, immediately after the driving, the control of the liquid crystal molecules cannot be performed normally, and flickering (light flickering) may occur.

Polyimide-based liquid crystal alignment film in response to the above Request, but there are various proposals. For example, a liquid crystal alignment agent containing a tertiary amine having a specific structure in addition to a poly-proline or a ruthenium-containing polyphthalic acid is used as a film which can shorten the application of a DC voltage to disappear. A liquid crystal alignment film of a time (for example, Patent Document 1) or a liquid crystal alignment agent containing a soluble polyimine (see Patent Document 2) having a specific diamine compound such as a pyridine skeleton as a raw material is proposed.

[Previous Technical Literature] [Patent Document]

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

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

Recently, with the increase in refinement, the problem of higher display quality than before, and the problem of voltage retention or charge accumulation has become more prominent. In particular, a liquid crystal display element of a transverse electric field type is formed on the base When there are few electrode parts in the board, when the voltage holding ratio of the liquid crystal alignment film is weak, sufficient voltage will not be supplied, and the display contrast will be lowered. In addition, when compared with the longitudinal electric field method, since the distance between the pixel electrode and the common electrode is short, the alignment film or the liquid crystal layer is strongly affected by the electric field, which causes a problem that the poor state is more conspicuous. Further, in recent years, in the liquid crystal display element, in order to obtain high luminance, there is a case where a backlight of a larger amount of light is used, and for the light generated by the backlight, stability of high voltage retention is also generated. demand. That is, it is sought to have an effect that the voltage holding ratio is not easily lowered even after being exposed to the backlight for a long period of time.

In addition, with the recent high-speed response of liquid crystals, liquid crystal In the case where impurities are mixed in, it is known that the voltage holding ratio of the liquid crystal display element is largely lowered. Further, in the manner in which liquid crystal molecules such as the IPS method or the FFS driving method are driven by a transverse electric field, the stability of the liquid crystal alignment is also extremely important. In the absence of alignment stability, when the liquid crystal is driven for a long time, the liquid crystal will return to the initial state, which is the reason for the contrast or the residual image or melt damage.

The present invention has been proposed in view of the above circumstances. A liquid crystal alignment agent which can be used for a liquid crystal display element which maintains a voltage holding ratio even when a long-term backlight is irradiated or a liquid crystal is mixed with impurities or the like, and the liquid crystal alignment agent can be obtained. The liquid crystal alignment film and the liquid crystal display element are prepared for the purpose.

The present invention has been thoroughly studied in order to achieve the above objectives. The present invention having the following main contents is completed.

A liquid crystal alignment agent 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, R is an alkyl group having 1 to 5 carbon atoms, and A ₁ and A ₂ each independently represent a hydrogen atom, or may have The alkyl group, the alkenyl group or the alkynyl group having 1 to 10 carbon atoms of the substituent, and at least a part of Y ₁ is a divalent organic group represented by the following formula (2).

(In the formula (2), D is a group having a carbon number of 1 to 20 selected from a saturated hydrocarbon group, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, and these may have a substituent, and m is 1 or 0. ).

2. The liquid crystal alignment agent of claim 1, wherein the divalent organic group represented by the formula (2) is from 1 to 99 mol% based on the entire Y ₁ in the formula (1).

3. The liquid crystal alignment agent of claim 1 or 2, wherein, in the divalent organic group represented by the formula (2) in the formula (1), D in the formula (2) is a carbon number of 1 to 20 A chain or cyclic alkyl group.

4. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein Y ₁ in the formula (1) is a divalent organic group represented by the formula (2), and Y-7, Y- 21. At least one selected from the group consisting of Y-28, Y-71, Y-72, and Y-119.

5. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein A ₁ and A ₂ each independently represent a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent, and any of It is a hydrogen atom.

6. The liquid crystal alignment agent according to any one of claims 1 to 5, wherein X ₁ in the formula (1) is at least one selected from the group consisting of the structures represented by the following formulas.

7. The liquid crystal alignment agent according to any one of claims 1 to 6, wherein The foregoing organic solvent is composed of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidine Ketone, N-ethyl-2-pyrrolidone, N-methyl caprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl hydrazine, dimethyl hydrazine, One or more selected from the group consisting of γ-butyrolactone, 1,3-dimethyl-tetrahydroimidazolidone, and 3-methoxy-N,N-dimethylpropane decylamine, .

8. The liquid crystal alignment agent according to any one of claims 1 to 7, wherein the polyglycolate content is 5 to 95 mass of the total polymer when the polyglycolate contains other polymers simultaneously. %.

A liquid crystal alignment film characterized in that a request item is The liquid crystal alignment agent of any one of 1 to 8 is applied to a substrate and sintered at 150 to 300 ° C to obtain a liquid crystal alignment agent.

A liquid crystal display element comprising the liquid crystal alignment film of claim 9.

11. The liquid crystal display element of claim 10, wherein the liquid crystal molecules that are parallel aligned with respect to the substrate are driven by a transverse electric field.

In the liquid crystal display element obtained by the liquid crystal alignment agent of the present invention, the liquid crystal display element having the liquid crystal alignment film can maintain a high voltage holding ratio and a high level even after long-term backlight irradiation and impurities are mixed in the liquid crystal. Liquid crystal alignment.

[Formation of the Invention] <Polyurethane>

The liquid crystal alignment agent of the present invention contains a polyphthalate having a repeating unit represented by the above formula (1).

In the above formula (1), X ₁ is a tetravalent organic group, and Y ₁ is a divalent organic group. R is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms. A ₁ and A ₂ each independently represent a hydrogen atom, or may have a substituent having 1 to 10 carbon atoms, preferably an alkyl group, an alkenyl group or an alkynyl group having 1 to 3 carbon atoms. Further, at least a part of Y ₁ is a divalent organic group represented by the above formula (2).

The polyperurethane may be one of the above-mentioned R, A ₁ , A ₂ , X ₁ and Y ₁ , that is, a polyphthalate composed only of repeating units of the same structure, or R, A ₁ , A ₂ , X ₁ and Y _{1 may} each be plural, that is, a polyperurethane having a repeating unit of several kinds of different structures. But, wherein Y ₁ must contain at least one of the above formula (2) represents the divalent organic group of the unit.

In the above formula (2), D is a carbon number of 1 to 20 selected from a saturated hydrocarbon group, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, and preferably has a valence of 2 to 5 carbon atoms. Has a substituent. m is 1 or 0.

In the structure of the above formula (2), the portions of the two benzene rings are bonded to NA ₁ or NA _{2 of the} formula (1), respectively. The bonding position of NA ₁ or NA ₂ on the benzene ring is not particularly limited, but based on the viewpoint of synthesizing difficulty or raw material availability, based on the indole linkage of D in the formula (2) It is better to bond to the position of the meta or para position respectively, and the position of the alignment is particularly good in terms of the alignment of the liquid crystal. Further, the hydrogen atom of the benzene ring in the formula (2) may be substituted by a fluorine atom, a methyl group, a trifluoromethyl group, a cyano group or a methoxy group. It can be used in combination with the availability of raw materials, etc., and it is preferable to use unsubstituted ones.

D in formula (2) is a saturated hydrocarbon group or an unsaturated hydrocarbon The carbon number of the group, the aromatic hydrocarbon group, and the hetero ring is preferably 1 to 20, preferably a valence of 1 to 5 carbon atoms, and these may have a substituent. From the viewpoint of electrical properties or solubility, a divalent hydrocarbon group or the like is preferred, and a linear alkyl group or a cyclic alkyl group is particularly preferred. The hydrocarbon group may have an unsaturated bond, and further, the hydrogen atom may be substituted by a carboxylic acid group or a fluorine atom or the like. Further, from the viewpoint of liquid crystal alignment properties or electrical properties, a divalent aromatic hydrocarbon group or a heterocyclic ring or the like is preferred. From the viewpoint of liquid crystal alignment, D is preferably one having no substituent, but from the viewpoint of solubility, it is preferred that a hydrogen atom is substituted by a carboxylic acid group or a fluorine atom.

In the repeating unit represented by the above formula (1), Y ₁ is a ratio of the divalent organic group represented by the formula (2), and all of the Y ₁ is a divalent organic group represented by the formula (2). However, when the liquid crystal alignment film of the present invention is provided with more characteristics, it is preferable to further contain a structure other than the divalent organic group represented by the formula (2) as Y ₁ of the formula (1). In this case, when a preferred ratio of the divalent organic group represented by the formula (2) is to be expressed, for example, Y in the repeating unit represented by the formula (1) included in the liquid crystal alignment agent of the present invention ₁ whole, the divalent organic group represented by the formula (2) is 1 to 99 mol%, preferably 1 to 50 mol%, more preferably 5 to 30 mol%, and most preferably 5 to 20 mol. ear%. Further, when the divalent organic group represented by the formula (2) contains a plurality of kinds, it means the total amount thereof.

The structure of Y ₁ other than the divalent organic group represented by the formula (2) is not particularly limited, and preferred examples thereof include the following Y-1 to Y-100. These Y ₁ may be mixed in two or more types.

In these Y ₁ , the viewpoint of improving the liquid crystal alignment property is better, and it is preferable to introduce a structure having high linearity into the polyphthalate, and Y ₁ is 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 preferable to introduce a structure in which a side chain has a long-chain alkyl group, an aromatic ring, an aliphatic ring, a cholesterol skeleton, or a combination of the structures obtained in the polyphthalate. ₁ to 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. The plurality of configuration, with respect to all the Y _1, preferably from 1 to 50 mole%, the pretilt angle can be obtained any. On the other hand, in order to obtain a liquid crystal alignment film which can alleviate residual charges accumulated in a liquid crystal display element via a DC voltage as early as possible, Y-101 to Y-118 are more preferable, and Y-111 and Y-114 are used. Y-115, Y-116 is especially good.

Y _{1 of the} structure other than the above formula (2) is preferably 50 to 99 mol% of the entire Y _{1 of} the formula (1), preferably 70 to 95 mol %, more preferably 80 to 95 mol %.

In the above formula (1), X ₁ is a tetravalent organic group, and the structure thereof is not particularly limited, and may be obtained by mixing two or more types of structures. Specific examples of X ₁ When exemplified, X-1 to X-46 as shown below are exemplified. Among them, from the viewpoint of the availability of raw material monomers, 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, X-46, etc. are preferred. For the viewpoint of obtaining a liquid crystal alignment film having a higher transmittance, X-1, X-2, X-3, X-4, X-5, X-6, X-8, X- having an aliphatic structure are used. 16, X-25, or X-46 is better, with X-1, or X-2 is particularly good.

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

In the above formula (1), A ₁ and A ₂ each independently represent a hydrogen atom, or an alkyl group, an alkenyl group or an alkynyl group having a carbon number of 1 to 10, preferably 1 to 3, which may have a substituent.

Specific examples of the alkyl group of A ₁ and A ₂ include a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, a hexyl group, an octyl group, a decyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the alkenyl group include those in which one or more CH-CH structures present in the above-mentioned alkyl group are replaced by a C=C structure, and more specifically, for example, a vinyl group, an allyl group, and 1 a propylene group, an isopropenyl group, a 2-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 CH2-CH2 structures present in the above-mentioned alkyl group are substituted by a C≡C structure, and more specifically, for example, an ethynyl group or a 1-propynyl group. , 2-propynyl and the like.

The above alkyl group, alkenyl group or alkynyl group may have a substituent in the case where the total carbon number is from 1 to 10, preferably from 1 to 3, and may form a ring structure with a substituent. Further, the meaning of forming a ring structure with a substituent means that the substituents are bonded to each other or a part of the main skeleton (i.e., an atom constituting A ₁ or A ₂ ) to form a ring structure.

Examples of the substituent are a halogen group, a hydroxyl group, a thiol group, Nitro, aryl, organooxy, organothio, organodecyl, decyl, ester, thioester, phosphate, decyl, alkyl, alkenyl, alkynyl, and the like.

The halogen group as a substituent may, for example, be a fluorine atom, a salt atom, a bromine atom, an iodine atom, and the like.

The aryl group as a substituent may, for example, be a phenyl group or the like. The The aryl group may be further substituted with the other substituents described above.

As the substituent of the organooxy group, the knot represented by O-R Structure. R may be the same or different, and examples thereof include the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group and the like. Among these R, it may be further substituted by the aforementioned substituent. Specific examples of the organic oxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group.

As the organic sulfur group of the substituent, the knot represented by -S-R may be used. Structure. Examples of the R include, for example, the alkyl group, the alkenyl group, the alkynyl group, and the aryl group. Among these R, it may be further substituted by the aforementioned substituent. 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, and an octylthio group.

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 examples thereof include the alkyl group, the alkenyl group, the alkynyl group, and the aryl group. Among these R, it may be further substituted by the aforementioned substituent. Specific examples of the organic decyl group include, for example, a trimethyl decyl group, a triethyl decyl group, a tripropyl decyl group, a tributyl decyl group, a trimethyl decyl group, a trihexyl decyl group, a pentyl dimethyl decyl group, and a hexyl dimethyl group.矽 alkyl and the like.

As the thiol group of the substituent, the structure represented by -C(O)-R may be used. Said. Examples of the R include, for example, the alkyl group, the alkenyl group, the aryl group and the like. Among these R, it may be further substituted by the aforementioned substituent. 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 isoamyl group, and a benzamidine group.

As the ester group of the substituent, it may be -C(O)O-R, or Structure representation shown by -OC(O)-R. Examples of the R include, for example, the alkyl group, the alkenyl group, the alkynyl group, and the aryl group. Among these R, it may be further substituted by the aforementioned substituent.

As the thioester group of the substituent, it may be -C(S)O-R, or -OC(S)-R is represented by the structure shown. Examples of the R include, for example, the alkyl group, the alkenyl group, the alkynyl group, and the aryl group. Among these R, it may be further substituted by the aforementioned substituent.

The phosphate group as a substituent can be represented by a structure represented by -OP(O)-(OR) ₂ . The R may be the same or different, and examples thereof include the alkyl group, the alkenyl group, the alkynyl group, and the aryl group. Among these R, it may be further substituted by the aforementioned substituent.

As the substituent amide group, it may be -C(O)NH ₂ , or -C(O)NHR, -NHC(O)R, -C(O)N(R) ₂ , -NRC(O)R Indicated by the structure shown. R may be the same or different, and examples thereof include the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group and the like. Among these R, it may be further substituted by the aforementioned substituent. Examples of the substituent of the hydrogen atom replacing R include an aryl group and the like. The aryl group as the substituent may, for example, be the same as the above-mentioned aryl group. The aryl group may be further substituted with the other substituents described above.

The alkyl group as a substituent may, for example, be the same as the aforementioned alkyl group. For the same content and so on. The alkyl group may be further substituted with the other substituents described above.

The alkenyl group as a substituent may, for example, be the same as the aforementioned alkenyl group For the same content and so on. The alkenyl group may be further substituted with the other substituents described above.

Examples of the alkynyl group as a substituent include, for example, the alkynyl group described above. For the same content and so on. The alkynyl group may be further substituted with the aforementioned other substituents.

In general, when a high-volume structure is introduced, there is a possibility that the reactivity of the amine group or the liquid crystal alignment property is lowered, so A ₁ and A ₂ may be a hydrogen atom or an alkyl group having 1 to 5 carbon atoms which may have a substituent. The base is more preferably a hydrogen atom, a methyl group or an ethyl group.

Further, the polyphthalocyanate contained in the liquid crystal alignment agent of the present invention can be obtained by a polymer having a site capable of undergoing the following imidization reaction by heating, thereby obtaining a polyimine imine precursor of polyimine. It is preferred that the body is at least one of A ₁ and A ₂ as a hydrogen atom.

(R is the same as R in the formula (1)).

<Method for producing polyamidomate>

The polyglycolate used in the present invention can be synthesized by the methods (1) to (3) shown below.

(1) The case of synthesis from polyaminic acid

Polyamidomates can be synthesized in a manner that is polyamidated.

Polylysine can be synthesized by reacting a tetracarboxylic dianhydride with a diamine. Specifically, for example, the tetracarboxylic dianhydride and the diamine are allowed to stand in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, for 30 minutes to 24 hours. It is preferably synthesized in 1 to 12 hours. The organic solvent used in the above reaction, the dissolution of the monomer and the polymer In view of the nature, N,N-dimethylformamide, N-methyl-2-pyrrolidone, and γ-butyrolactone are preferred. These may be used alone or in combination of two or more. The concentration of the polymer is less likely to cause precipitation of the polymer, and it is preferable to obtain a high molecular weight body, and it is preferably 1 to 30% by mass, and preferably 5 to 20% by mass. The polylysine obtained in this manner can be recovered by precipitating the polymer when the reaction solution is thoroughly stirred and injected into a poor solvent. Further, the precipitated powder is washed several times, washed with a poor solvent, and then heated or dried by heating to obtain a purified powder of poly-proline. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, cellosolve, acetone, toluene, and the like.

In the polyesterification, poly-proline and esterification agents Preferably, it is synthesized in the presence of an organic solvent at a temperature of from -20 ° C to 150 ° C, preferably from 0 ° C to 50 ° C, for from 30 minutes to 24 hours, preferably from 1 to 4 hours.

The esterifying agent is preferably one which can be easily removed by refining, N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N - dimethylformamide dipropyl acetal, N,N-dimethylformamide dinepentyl 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-three -2-yl)-4-methylmorpholinium chloride and the like. The amount of the esterifying agent to be added is preferably 2 to 6 mol equivalents per 1 mol of the repeating unit of the polyamic acid.

The solvent used in the above reaction, the dissolution of the polymer Sexually, N,N-dimethylformamide, N-methyl-2-pyrrolidone, or Γ-butyrolactone is preferred, and one type may be used alone or two or more types may be used in combination. The concentration at the time of synthesis is less likely to cause precipitation of the polymer, and it is preferable to obtain a high molecular weight body, preferably from 1 to 30% by mass, and preferably from 5 to 20% by mass.

(2) Synthesis by reaction of dicarboxylic acid diester dichloride with diamine

The polyglycolate can be synthesized from a dicarboxylic acid diester dichloride and a diamine.

Specifically, for example, the dicarboxylic acid diester dichloride and the diamine are carried out in the presence of a base and an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C. It can be synthesized in a minute to 24 hours, preferably in a reaction time of 1 to 4 hours.

Among the above-mentioned bases, pyridine, triethylamine, 4-dimethylaminopyridine or the like can be used, and pyridine is preferred from the viewpoint of allowing the reaction to proceed stably. The amount of the base to be added is easily removed, and the viewpoint of easily obtaining a high molecular weight body is preferably 2 to 4 times moles relative to the dicarboxylic acid diester dichloride.

The solvent used for the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone from the viewpoint of solubility of the monomer and the polymer, and one type or two types may be used. The above is mixed. The concentration of the polymer at the time of synthesis is less likely to cause precipitation of the polymer, and it is preferable to obtain a high molecular weight body, preferably from 1 to 30% by mass, and preferably from 5 to 20% by mass. Further, in order to prevent hydrolysis of the dicarboxylic acid diester dichloride, the solvent used for the synthesis of the polyphthalate is preferably used as far as possible, and the nitrogen atmosphere is preferred. In order to prevent other gases from mixing in, it is better.

(3) The case of synthesizing poly-proline from dicarboxylic acid diester and diamine

The polyglycolate can be synthesized by polycondensation of a dicarboxylic acid diester and a diamine.

Specifically, for example, the dicarboxylic acid diester and the diamine may be used 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, for 30 minutes to 24 hours. It can be synthesized in an hour, preferably from 3 to 15 hours.

Among the above condensing agents, triphenylphosphite, dicyclohexylcarbonyldiimide, and 1-ethyl-3-(3-dimethylaminopropyl)carbonyldiimide hydrochloride can be used. N,N'-carbonyldiimidazole, dimethoxy-1,3,5-three Methylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(benzotriazole-1- -N,N,N',N'-tetramethyluronium hexafluorophosphate, diphenyl(2,3-dihydro-2-thioketo-3-benzoxazolyl)phosphonic acid Salt and so on. The amount of the condensing agent added is preferably 2 to 3 moles per mole of the dicarboxylic acid diester.

Among the above bases, three stages of pyridine, triethylamine, etc. can be used. amine. The amount of the base to be added is easily removed, and the viewpoint of easily obtaining a high molecular weight body is preferably 2 to 4 times the molar amount of the diamine component.

Further, in the above reaction, Lewis acid is added as an additive. At this time, the reaction can be carried out efficiently. Lewis acid is preferably lithium halide such as lithium chloride or lithium bromide. The addition amount of Lewis acid is preferably 0 to 1.0 times the molar amount of the diamine component.

In the above three methods for synthesizing polyglycolate, From the viewpoint of the high molecular weight polyglycolate, the synthesis method of the above (3) is particularly preferable.

a solution of the polyamidoate obtained by the above method, When the lean solvent is injected into the stirring, the polymer can be precipitated. After several times of precipitation, washing with a poor solvent, the powder of the purified polyphthalate can be obtained by heating at room temperature or by heating. The poor solvent is not particularly limited, and examples thereof include water, methanol, isopropanol, ethanol, hexane, cellosolve, acetone, toluene, and the like.

<Liquid alignment agent>

The liquid crystal alignment agent of the present invention is in the form of a solution obtained by dissolving a polyperurethane (hereinafter also referred to as a specific polymer) having a repeating unit represented by the above formula (1) in an organic solvent. The molecular weight of the specific polymer has a weight average molecular weight (Mw) of preferably 2,000 to 500,000, preferably 5,000 to 300,000, more preferably 8,000 to 100,000. Further, the number average molecular weight (Mn) is preferably from 1,000 to 250,000, more preferably from 2,500 to 150,000, most preferably from 4,000 to 50,000.

The organic solvent contained in the liquid crystal alignment agent of the present invention, only There is no particular limitation on the case where a specific polymer can be uniformly dissolved. Specific examples thereof include, for example, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidine Ketone, N-ethyl-2-pyrrolidone, N-methyl caprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl hydrazine, dimethyl hydrazine, Γ-butyrolactone, 1,3-dimethyl Base-tetrahydroimidazolidinone, 3-methoxy-N,N-dimethylpropane decylamine, and the like. These may be used alone or in combination of two or more. Further, even if it is not possible to uniformly dissolve the solvent of the specific polymer alone, it may be mixed with the above-mentioned organic solvent as long as it does not precipitate the polymer.

The organic solvent contained in the liquid crystal alignment agent of the present invention, In addition to the organic solvent used for the specific polymer, the solvent used for the uniformity of the coating film can be improved when the liquid crystal alignment agent is applied to the substrate. The solvent is generally a solvent having a lower surface tension than the above organic solvent. When specific examples are given, for example, cellosolve, cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1 -Methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol Diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, butyl cellosolve acetate, dipropylene glycol, 2- (2-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and the like. These solvents can be used in combination of two types.

In the liquid crystal alignment agent of the present invention, in addition to the above components Further, a polymer other than a specific polymer or various additives may be contained insofar as the effects of the present invention are not impaired.

A polymer other than a specific polymer, for example, polyfluorene A polyimide precursor such as an amine acid or a polyphthalate, a polyimine, a polyamine, a polyoxyalkylene, an acrylic polymer or the like. In particular, poly-proline is used to increase the rate of residual charge accumulated in the liquid crystal display device via driving. It is useful for the degree. In the case where the liquid crystal alignment agent of the present invention contains a polymer other than the specific polymer, the ratio of the specific polymer to the total amount of the polymer contained in the liquid crystal alignment agent is preferably 5 to 95% by mass. In the case where the polyglycine is contained for the purpose of increasing the rate of the residual charge, the ratio of the specific polymer is preferably 5 to 60% by mass, preferably 5, based on the total amount of the specific polymer and the polyamic acid. ~40% by mass.

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

Various additives contained in the liquid crystal alignment agent can be enumerated For example, a decane coupling agent for the purpose of changing the dielectric properties of the liquid crystal alignment film, such as a dielectric constant or conductivity, and a dielectric material for improving the adhesion between the liquid crystal alignment film and the substrate, and as a liquid crystal alignment film A cross-linking compound for the purpose of improving the hardness or the density of the film, and in addition, in the case of sintering of the coating film, the imine imine can be efficiently carried out by heating the polyimide precursor. Promoters, etc.

<Liquid alignment film>

The liquid crystal alignment film of the present invention is a film obtained by applying the above liquid crystal alignment agent to a substrate, drying and sintering. The substrate to which the liquid crystal alignment agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as a glass substrate, a tantalum nitride substrate, an acrylic substrate or a polycarbonate substrate can be used. , in terms of simplification of the process, to use the shape It is preferable to form a substrate such as an electrode for liquid crystal driving. Further, in the reflective liquid crystal display device, since it is only necessary to use a single-sided substrate, an opaque such as a germanium wafer can be used. In this case, a material such as aluminum which can reflect light can be used.

The coating method of the liquid crystal alignment agent of the present invention can be enumerated For example, coating by a spin coating method, a printing method, an inkjet method, or the like. The drying and sintering steps after the liquid crystal alignment agent of the present invention can be selected to any temperature and time. Usually, from the viewpoint of sufficiently removing the organic solvent contained, it is dried at 50 ° C to 120 ° C for 1 minute to 10 minutes, and then sintered at 150 ° C to 300 ° C for 5 minutes to 120 minutes. The thickness of the coating film after sintering is not particularly limited, but when it is too thin, there is a case where the reliability of the liquid crystal display element is lowered, so it is usually 5 to 300 nm, preferably 10 to 200 nm.

a method for performing alignment treatment on the obtained liquid crystal alignment film, For example, a rubbing method, a photoalignment processing method, and the like. Specific examples of the photo-alignment treatment method include a method of irradiating a radiation line deflected in a certain direction to the surface of the coating film, and if necessary, heating at a temperature of 150 to 250 ° C to impart a liquid crystal alignment ability. Wait. For the radiation, ultraviolet rays and visible rays having a wavelength of 100 nm to 800 nm can be used.

As described above, the liquid obtained from the liquid crystal alignment agent of the present invention Since the crystal alignment film has excellent characteristics, it can be used as a liquid crystal display element such as VA, TN, STN, TFT, and a lateral electric field type, and even a liquid crystal alignment for a liquid crystal display element having a strong dielectric property and an anti-strong dielectric property. membrane.

<Liquid crystal display element>

In the liquid crystal display device of the present invention, a substrate having a liquid crystal alignment film can be obtained from the liquid crystal alignment agent of the present invention according to the above method. After the alignment treatment by rubbing treatment or the like, it can be used as a liquid crystal display element by a known method.

The method for producing the liquid crystal cell of the liquid crystal display element is not particularly limited. For example, a pair of substrates on which a liquid crystal alignment film is formed, and a liquid crystal alignment film facing inward is preferably provided. After the spacer of 1 to 30 μm, more preferably 2 to 10 μm, the method of fixing with a sealant around, and then injecting the liquid crystal and sealing it is a general method. The liquid crystal sealing method is not particularly limited, and examples thereof include a vacuum method in which a liquid crystal cell to be produced is decompressed and then injected into a liquid crystal, and a dropping method in which a liquid crystal is dropped and then sealed.

[Examples]

The invention will be described in more detail below by way of examples, but the invention is not limited thereto.

Description of the abbreviation used in this embodiment

<organic solvent>

NMP: N-methyl-2-pyrrolidone

BCS: butyl cellosolve (cellosolve)

<tetracarboxylic acid derivative>

TC-1: 2,4-bis(methoxycarbonyl)cyclobutane-1,3-dicarboxylic acid

TC-2: 3,3',4,4'-biphenyltetracarboxylic dianhydride

<Diamine>

DA-1: bis(4-aminophenoxy)methane

DA-2: N-(4-aminophenyl)-N-methylbenzene-1,4-diamine

DA-3: 1,3-bis(4-aminophenethyl)urea

DA-4: N1, N4-bis[(2-tert-butoxycarbonylamino)-4-nitrophenyl]hexanediamine

DA-5: 4,4'-diaminodiphenylamine

DA-6: 3,5-diamino benzoic acid

<condenser>

DBOP: diphenyl (2,3-dihydro-2-thioketo-3-benzoxazolyl)phosphonate

<Synthesis of DA-4>

The diamine DA-4 used in this example was synthesized in the following manner.

2-tert butoxycarbonyl in a 500 mL four-necked flask 20.0 g (78.97 mmol) of arylamino-4-nitroaniline and 15.6 g (197.43 mmol) of pyridine were dissolved in a mixed solvent of 300 ml of dehydrated THF and 100 ml of DMF, and kept at 10 ° C or less in an ice bath. Under a tempering atmosphere, a THF solution (20 wt%) of 6.5 g (35.54 mmol) of adipoyl chloride was slowly added dropwise using a dropping funnel, followed by stirring for 24 hours to carry out a reaction. A solid precipitated as the reaction progressed. After the completion of the reaction, 300 ml of pure water was added to the reaction solution, and the mixture was stirred for a while, and the reaction solution was poured into 1 L of methanol, followed by stirring for a while. The solid was filtered and washed several times with 500 ml of methanol to give a white solid, 19.5 g (yield: 89%). The solid obtained was N1,N4-bis[(2-tert-butoxycarbonylamino)-4-nitrophenyl]hexanediamine.

Subsequently, it is equipped with a three-way cock and a stirrer 300mL In a four-necked flask, 15.0 g of N1,N4-bis[(2-tert-butoxycarbonylamino)-4-nitrophenyl]hexanediamine and 1.5 g of palladium carbide (5 wt%) were added. 250 ml of DMF was subjected to vacuum degassing and hydrogen substitution, and reacted at room temperature for 48 hours.

After completion of the reaction, palladium carbide was removed using a membrane filter made of PTFE (polytetrafluoroethylene), and the filtrate was poured into 500 ml of methanol cooled to 10 ° C or lower, and stirred for a while to precipitate a solid. The obtained solid was recovered, washed with methanol, and washed with a mixed solvent of ethyl acetate and n-hexane, and dried under vacuum at 60 ° C to obtain a diamine solid of 12.2 g (yield: 90%). The obtained solid was [DA-4]. Its structure was confirmed by ¹ H-NMR spectrum of a nuclear magnetic resonance spectrum of intramolecular hydrogen atoms. The measurement data is as follows.

¹ H NMR (400 MHz, [D ₆ ]-DMSO) δ: 9.19 (s, 2H), 7.97 (s, 2H), 7.00 (dd, 2H), 6.83 (d, 2H), 6.33 (dd, 2H), 5.04 (s-br, 4H), 2, 50 (m, 4H), 1.44 (m, 4H), 1.48 (s, 18H)

The following are methods for measuring the viscosity of the polymer solution and the molecular weight of the polymer.

[viscosity]

In the synthesis example, the viscosity of the polyaminic acid solution or the polyamidate solution is The E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) was used, and the measurement was carried out at a sample amount of 1.1 mL, a cone-type rotational viscometer TE-1 (1°34', R24), and a temperature of 25 °C.

[molecular weight]

The molecular weights of polyglycine and polyglycolate were measured using a GPC (normal temperature gel permeation chromatography) apparatus, and Mn and Mw were calculated in terms of polyethylene glycol and polyoxyethylene.

GPC device: (share) made by Shodex (GPC-101)

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

Column temperature: 50 ° C

Dissolution: N,N-dimethylformamide (additive, lithium bromide-water (LiBr.H2O) is 30 mmol/L, phosphoric acid. anhydrous crystal (o-phosphoric acid) is 30 mmol/L, tetrahydrofuran (THF) 10ml/L)

Flow rate: 1.0ml/min

Standard sample for calibration line preparation: TSK standard polyoxyethylene (Mw: about 900,000, 150,000, 100,000, 30,000) made by Tosoh Corporation, and polyethylene glycol manufactured by Polymer Research Co., Ltd. (molecular weight (Mp) of about 12,000, 4,000) , 1,000). In the measurement, in order to avoid peak repetition, two kinds of samples of a mixture of four types of 900,000, 100,000, 12,000, and 1,000, and a sample of three types of 150,000, 30,000, and 4,000 were separately measured.

(Synthesis Example 1)

After 4.94 g (19.0 mmol) of the tetracarboxylic acid derivative TC-1 was placed in a four-necked flask equipped with a stirrer, 95.0 g of NMP was added thereto, and the mixture was stirred and dissolved. Next, 6.07 g (60.0 mmol) of triethylamine, 3.45 g (15.0 mmol) of diamine DA-1, 0.895 g (3 mmol) of diamine DA-3, and 1.11 g (1.50 mmol) of diamine DA-4 were added. Stir to dissolve.

While stirring this solution, 16.1 g (42.0 mmol) of a condensing agent DBOP was added, and 16.8 g of NMP was further added thereto, and the mixture was stirred at room temperature for 12 hours to obtain a solution of a polyamidite ester. The viscosity of the polyphthalate solution at a temperature of 25 ° C is 43.4 mPa. s.

This polyamine ester solution was poured into 866 g of methanol, and the resulting precipitate was filtered off. This precipitate was washed with methanol, and then dried under reduced pressure at a temperature of 100 ° C to obtain a polyglycolate powder (PAE-a1) of a specific polymer. The molecular weight of the polyglycolate was Mn = 13,612 and Mw = 31,063.

(Synthesis Example 2)

After 4.94 g (19.0 mmol) of the tetracarboxylic acid derivative TC-1 was placed in a four-necked flask equipped with a stir bar, 101.4 g of NMP was added thereto, and the mixture was stirred and dissolved. Next, 6.07 g (60.0 mmol) of triethylamine, 2.99 g (13.0 mmol) of diamine DA-1, 0.90 g (3.00 mmol) of diamine DA-3, and 2.23 g (4.00 mmol) of diamine DA-4 were added. Thereafter, stirring was carried out to dissolve.

While stirring this solution, 16.1 g (42.0 mmol) of a condensing agent DBOP was added, and 16.8 g of NMP was further added thereto, and the mixture was stirred at room temperature for 12 hours to obtain a solution of a polyamidite ester. This polyphthalate solution at temperature The viscosity at 25 ° C is 41.5 mPa. s.

This polyamine ester solution was poured into 915 g of methanol, and the resulting precipitate was filtered. After the precipitate was washed with methanol, it was dried under reduced pressure at a temperature of 100 ° C to obtain a powder of a specific polymer polyamine (PAE-a2). The molecular weight of this polyphthalate was MN = 14,618 and Mw = 33,564.

(Synthesis Example 3)

After 106.5 g (0.41 mol) of the tetracarboxylic acid derivative TC-1 was placed in a four-necked flask equipped with a stirrer, 2,120 g of NMP was added, and the mixture was stirred and dissolved. Next, 133.6 g (1.32 mol) of triethylamine, and 45.59 g (0.20 mol) of diamine DA-1, 28.15 g (0.13 mol) of diamine DA-2, and 19.69 g (0.07 mol) of diamine DA-3 were added. After 24.49 g (0.044 mol) of diamine DA-4, it was stirred and dissolved.

While stirring this solution, 313.7 g (0.82 mol) of a condensing agent DBOP was added, and 291.2 g of NMP was further added thereto, and the mixture was stirred at room temperature for 12 hours to obtain a solution of a polyamidite ester. The polyglycolate solution has a viscosity of 36.5 mPa at a temperature of 25 ° C. s.

This polyamine ester solution was poured into 915 g of methanol, and the resulting precipitate was filtered. After the precipitate was washed with methanol, it was dried under reduced pressure at a temperature of 100 ° C to obtain a powder of a specific polymer polyacetate (PAE-a3). The molecular weight of this polyphthalate was Mn = 13,113 and Mw = 30,067.

(Synthesis Example 4)

Into a four-necked flask placed in a stirrer, the tetracarboxylic acid derivative TC- was introduced. After 12.55 g (9.80 mmol), 45.0 g of NMP was added and stirred to dissolve. Next, 2.13 g (21.0 mmol) of triethylamine, 1.96 g (8.50 mmol) of diamine DA-1, and 0.45 g (1.50 mmol) of diamine DA-3 were added, and the mixture was stirred and dissolved.

While stirring this solution, 8.05 g (21.0 mmol) of a condensing agent DBOP was added, and 7.94 g of NMP was further added thereto, and the mixture was stirred at room temperature for 12 hours to obtain a solution of a polyamidite ester. The polyglycolate solution has a viscosity of 50.0 mPa at a temperature of 25 ° C. s.

This polyamine ester solution was poured into 408 g of methanol, and the resulting precipitate was filtered. After the precipitate was washed with methanol, it was dried under reduced pressure at a temperature of 100 ° C to obtain a powder of a polyglycolate (PAE-b1) which was not a specific polymer. The molecular weight of this polyphthalate was Mn = 12,542 and Mw = 35,098.

(Synthesis Example 5)

After 8.28 g (31.8 mmol) of the tetracarboxylic acid derivative TC-1 was placed in a four-necked flask in which a stirrer was placed, 45.0 g of NMP was added, and the mixture was stirred and dissolved. Next, 2.13 g (21.0 mmol) of triethylamine, 4.24 g (18.4 mmol) of diamine DA-1, 2.14 g (10.0 mmol) of diamine DA-2, and 1.50 g (5.00 mmol) of diamine DA-3 were added. Stir and dissolve.

While stirring this solution, 25.69 g (67.0 mmol) of a condensing agent DBOP was added, and 18.78 g of NMP was further added thereto, and the mixture was stirred at room temperature for 12 hours to obtain a solution of a polyamidite ester. The viscosity of the polyphthalate solution at a temperature of 25 ° C is 55.1 mPa. s.

The polyphthalate solution was poured into 1215 g of methanol to obtain a precipitate. Filter out. After the precipitate was washed with methanol, it was dried under reduced pressure at a temperature of 100 ° C to obtain a powder of a polyglycolate (PAE-b2) which was not a specific polymer. The molecular weight of this polyphthalate was Mn = 14,132 and Mw = 34,191.

(Example 1)

4.10 g of a polyacetate powder (PAE-a1) obtained in Synthesis Example 1 was placed in a 100 mL Erlenmeyer flask in which a stir bar was placed, and 64.2 g of NMP was added thereto, and the mixture was stirred at room temperature for 18 hours to be dissolved. Subsequently, 22.8 g of BCS was added and stirred for 2 hours to obtain a liquid crystal alignment agent (A-1) of a polyacetamide solution having a solid content of 4.40% by mass.

(Example 2)

3.81 g of the polyacetate powder (PAE-a2) obtained in Synthesis Example 2 was placed in a 100 mL Erlenmeyer flask in which a stir bar was placed, and 59.7 g of NMP was added thereto, and the mixture was stirred at room temperature for 18 hours to be dissolved. Subsequently, 21.2 g of BCS was added and stirred for 2 hours to obtain a liquid crystal alignment agent (A-2) of a polyphthalate solution having a solid content of 4.41% by mass.

(Example 3)

4.21 g of the polyacetate powder (PAE-a3) obtained in Synthesis Example 3 was placed in a 100 mL Erlenmeyer flask in which a stir bar was placed, and 66.0 g of NMP was added thereto, and the mixture was stirred at room temperature for 18 hours to be dissolved. Subsequently, 23.4 g of BCS was added, and after stirring for 2 hours, a liquid crystal alignment agent (A-3) of a polyacetamide solution having a solid content of 4.45 mass% was obtained.

(Comparative Example 1)

1.77 g of the polyacetate powder (PAE-b1) obtained in Synthesis Example 4 was placed in a 100 mL Erlenmeyer flask in which a stir bar was placed, and 27.7 g of NMP was added thereto, and the mixture was stirred at room temperature for 18 hours to be dissolved. Subsequently, 9.85 g of BCS was added, and after stirring for 2 hours, a liquid crystal alignment agent (B-1) having a solid concentration of 4.34% by mass of a polyamidate solution was obtained.

(Comparative Example 2)

3.87 g of the polyacetate powder (PAE-b2) obtained in Synthesis Example 5 was placed in a 100 mL Erlenmeyer flask in which a stir bar was placed, and 60.6 g of NMP was added thereto, and the mixture was stirred at room temperature for 18 hours to be dissolved. Subsequently, 21.5 g of BCS was added, and after stirring for 2 hours, a liquid crystal alignment agent (B-2) of a polyglycolate solution having a solid concentration of 4.30% by mass was obtained.

(Synthesis Example 6)

Into a four-necked flask equipped with a stirrer, 3.98 g (20.0 mmol) of diamine DA-5 and 0.76 g (5.00 mmol) of diamine DA-6 were charged, and then 54.5 g of NMP was added thereto, followed by stirring to dissolve. Next, 6.84 g (23.3 mmol) of the tetracarboxylic acid derivative TC-2 was added, and 30.4 g of NMP was added thereto, and the mixture was reacted at 40 ° C for 15 hours to obtain a solution of polyamic acid. The solution of the polyaminic acid has a viscosity of 570 mPa at 25 ° C. s. Further, the polyamine had a number average molecular weight of 13,700 and a weight average molecular weight of 32,300.

In the solution of polyamic acid, the polyglycine is up to 6 mass%, NMP and BCS were added in such a manner that NMP was 69% by mass and BCS was 25% by mass to prepare a polyaminic acid solution (D).

(Example 4)

In the powder of the polyphthalate obtained in Synthesis Example 1 (PAE-a1), NMP was added, and the mixture was stirred at 50 ° C for 30 hr to dissolve it, and then NMP and BCS were added to prepare a polyglycolate of 6 mass%. A solution having a NMP of 69% by mass and a BCS of 25% by mass. 6.10 g of the polyamidate solution and 14.0 g of the polyamidic acid solution (D) prepared in Synthesis Example 6 were placed in a conical flask in which a stir bar was placed, and stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent. (A-4).

(Example 5)

In the powder of the polyphthalate obtained in Synthesis Example 2 (PAE-a2), NMP was added, and after stirring at 50 ° C for 30 hr to dissolve it, NMP and BCS were added to prepare a polyglycolate of 6 mass%. A solution in which NMP is 69% by mass and BCS is 25% by mass. 6.00 g of the polyamidate solution and 13.9 g of the polyamidic acid solution (D) prepared in Synthesis Example 6 were placed in a conical flask in which a stir bar was placed, and stirred at room temperature for 3 hours to obtain a liquid crystal alignment. Agent (A-5).

(Comparative Example 3)

To the powder of the polyphthalate obtained in Synthesis Example 4 (PAE-b1), NMP was added, and after stirring at 50 ° C for 30 hr to dissolve, NMP was added. BCS was used to prepare a solution in which the polyamidamide was 6 mass%, the NMP was 69 mass%, and the BCS was 25% by mass. 6.00 g of the polyamidate solution and 14.0 g of the polyamic acid solution (D) prepared in Synthesis Example 6 were placed in a conical flask in which a stir bar was placed, and stirred at room temperature for 3 hours to obtain a liquid crystal alignment. Agent (B-3).

[Evaluation of resistance to backlighting of voltage holding ratio]

The backlight resistance of the voltage holding ratio was evaluated in the following manner.

(Production of liquid crystal cell for voltage retention measurement)

The liquid crystal alignment agent was filtered using a 1.0 μm filter, and then applied to a substrate with an electrode (a horizontal 30 mm × a longitudinal length of 40 mm and a thickness of 1.1 mm) using a spin coater. The electrode was 10 mm wide by 40 mm long. Rectangular, ITO electrode with a thickness of 35 nm). After drying on a hot plate at 50 ° C for 5 minutes, it was sintered in an IR oven at 230 ° C for 20 minutes to obtain a substrate having a liquid crystal alignment film formed by forming a coating film having a film thickness of 100 nm. The liquid crystal alignment film was rubbed with a nylon cloth (roller diameter: 120 mm, number of drum rotations: 1000 rpm, moving speed: 20 mm/sec, and pushed length: 0.4 mm), and then washed in pure water for 1 minute for ultrasonic cleaning to air. After the water droplets were removed by a stream, they were dried at 80 ° C for 15 minutes to obtain a substrate having a liquid crystal alignment film.

Two sheets of the substrate with the above liquid crystal alignment film were prepared, and after a spacer of 4 μm was spread on one of the liquid crystal alignment film surfaces, a sealant was printed thereon, and the other substrate was rubbed in the opposite direction. After the film faces are attached to each other, the sealant is hardened to form an empty unit cell. Liquid crystal ZLI-4792 (manufactured by Moker Corporation) was injected into the empty cell by a reduced pressure injection method, and sealed through an injection port to obtain a liquid crystal cell. Subsequently, the obtained liquid crystal cell was heated at 110 ° C for 1 hour, and left at 23 ° C overnight to obtain a liquid crystal cell for voltage retention measurement.

(Evaluation of backlight resistance)

A voltage of 1 V was applied to the liquid crystal cell for voltage holding rate measurement at 60 ° C for 60 μsec, and the voltage after 100 msec was measured, and the voltage holding ratio was calculated so as to maintain the voltage. It is the initial voltage holding ratio.

Next, this liquid crystal cell was allowed to stand under a temperature of 70 ° C and an LED light source (1000 cd) for 72 hours to perform a backlight resistance test. The voltage holding ratio of this liquid crystal cell was measured in the same manner as above. This was taken as the voltage holding ratio after the resistance test.

The backlight retention resistance of the voltage holding ratio was evaluated by the magnitude of the voltage holding ratio measured in the above manner. That is, compared with the initial voltage holding ratio, the smaller the amount of change in the voltage holding ratio after the resistance test, the better the backlight resistance is.

[Evaluation of the resistance to liquid crystal impurities in the voltage holding ratio]

The evaluation of the liquid crystal impurity tolerance of the voltage holding ratio was evaluated in the following manner.

In the liquid crystal ZLI-4792 (made by Mok), polyethylene glycol is added (and Wako Pure Chemical Industries Co., Ltd.: The average molecular weight of the light grade 1 product: 360~400) reaches 500ppm, and after being left at room temperature for 24 hours, it is mixed into the liquid crystal as an impurity.

The liquid crystal cell for voltage retention measurement was produced in the same manner as described above except that the liquid crystal injected into the empty cell was mixed with the liquid crystal using the above-described impurities. The liquid crystal cell was applied with a voltage of 1 V for 60 μsec at a temperature of 60 ° C, and the voltage after 100 msec was measured. The voltage holding ratio was calculated in such a manner as to maintain the voltage, and the liquid crystal impurity was mixed with the voltage holding ratio. Sex. That is, the voltage holding ratio of the liquid crystal cell in which a normal liquid crystal (liquid crystal without polyethylene glycol is added) is injected, and the voltage holding ratio of the liquid crystal cell in which the impurity is mixed into the liquid crystal is smaller, indicating that it is resistant to liquid crystal impurities. The better the mixing property.

[Evaluation of liquid crystal alignment]

The evaluation of the liquid crystal alignment is evaluated in the following manner.

(Preparation of the substrate with the electrode for the FFS method)

Prepare a substrate with an electrode for the FFS method. The substrate was a glass substrate having a size of 30 mm × 35 mm and a thickness of 0.7 mm. The first layer on the substrate is an IZO electrode that integrally forms a counter electrode. The second layer on the IZO electrode of the first layer is a film formed SiN (tantalum nitride) film by a CVD method. The SiN film of the second layer has a film thickness of 500 nm and has a function as an interlayer insulating film. On the SiN film of the second layer, a pixel electrode formed as a third layer by pattern formation by an IZO film is disposed, and two first pixels and a second pixel are formed. Picture. The size of each pixel is 10 mm in length and 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The third layer of the pixel electrode has a meandering shape composed of electrode elements having a "ㄑ" shape in which a central portion of the plurality of columns is bent. The width of each electrode element in the short-side direction was 3 μm, and the interval between the electrode elements was 6 μm. The pixel electrodes forming the respective pixels are composed of the electrode elements of the "ㄑ" shape in which the central portion of the plurality of pixels is arranged. Therefore, the shape of each pixel is not rectangular, but is the same as the electrode elements. It has a shape similar to the word "ㄑ" in which the central part is buckling and bold. Therefore, each pixel is divided up and down with the central flexion portion as a boundary, and has a first region on the upper side of the flexion portion and a second region on the lower side.

When the first region of each pixel is compared with the second region, the direction in which the electrode elements constituting the pixel elements are formed is different. In other words, in the first region of the pixel, the electrode element of the pixel electrode is formed at an angle of +10° (clockwise direction) in the first region of the pixel, and the second region of the pixel is in the first region of the pixel. The electrode elements of the pixel electrodes are formed at an angle of -10° (clockwise). In other words, the voltage applied to the first region and the second region of each pixel is applied to the liquid crystal in the plane of the substrate (transverse electric field effect; IN PLANE SWITCHING) caused by the pixel electrode and the counter electrode. The direction is the opposite direction of each other.

(Production of liquid crystal cell for liquid crystal alignment evaluation)

The liquid crystal alignment agent was filtered using a 1.0 μm filter, and then applied to the electrode-attached substrate for the FFS method described above using a spin coater. After drying on a hot plate at 100 ° C for 100 seconds, it was sintered in a hot air circulating oven at 230 ° C for 20 minutes to obtain a polyimide film having a film thickness of 60 nm. The polyimide film was rubbed with a nylon cloth (roller diameter: 120 mm, number of drum rotations: 500 rpm, moving speed: 30 mm/sec, pushing length: 0.3 mm, rubbing direction: tilting 10° to the third layer IZO 栉歯 electrode) After the direction), the mixture was irradiated with ultrasonic waves for 1 minute in a mixed solvent of isopropyl alcohol and pure water in 3/7, and the water droplets were removed by air flow, and then dried at 80 ° C for 15 minutes to obtain a liquid crystal alignment film. The substrate.

Further, the counter substrate is a glass substrate having a columnar spacer having a height of 4 μm and having ITO formed therein, and a polyimide film is formed by the same method as described above, and subjected to alignment treatment in the same order as above. A substrate with a liquid crystal alignment film attached thereto.

The two substrates with the liquid crystal alignment film are used as one set, and the sealant is printed so that the liquid crystal injection port is left on the substrate, and the other substrate is oriented opposite to the liquid crystal alignment film surface, and the rubbing direction is antiparallel. After the bonding, the sealant was hardened to obtain an empty unit cell having a cell pitch of 4 μm.

Liquid crystal ZLI-4792 (manufactured by Moker Corporation) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS liquid crystal cell. Subsequently, the obtained liquid crystal cell was heated at 110 ° C for 30 minutes and left at 23 ° C overnight to prepare a liquid crystal cell for evaluating liquid crystal alignment.

(Evaluation of liquid crystal alignment)

The liquid crystal cell for liquid crystal alignment evaluation described above was subjected to an alternating current voltage of 100% with a frequency of 30 Hz at a cycle number of 30 Hz for 168 hours in a constant temperature environment of 60 °C. Subsequently, a state in which a short circuit between the pixel electrode of the liquid crystal cell and the counter electrode is formed is performed, and in this state, it is left at room temperature for one day. After being placed, the liquid crystal cell is placed between the two polarizing plates arranged vertically on the polarizing axis, and the backlight is placed in a state where no voltage is applied, and the arrangement angle of the liquid crystal cell is adjusted to the brightness of the transmitted light. Until the minimum. Then, the rotation angle of the liquid crystal cell when the darkest angle of the second region of the first pixel is rotated to the darkest angle of the first region is calculated as the angle Δ. Similarly to the second pixel, the second region and the first region are compared, and the same angle Δ is calculated. Subsequently, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell, and the liquid crystal alignment property was evaluated by the magnitude of the value. That is, the smaller the value of the angle Δ is, the better the liquid crystal alignment property is.

In Table 1 below, the use of Examples 1 to 5 for comparison and comparison The evaluation results of the backlight resistance of the voltage holding ratio of the liquid crystal cell prepared by the liquid crystal alignment agent obtained in Example 3.

In Table 2 below, the use of Examples 1 to 3 for comparison and comparison The liquid crystal cell prepared by the liquid crystal alignment agent obtained in Examples 1 to 2 was evaluated for the liquid crystal impurity-immiscibility and the liquid crystal alignment property. Further, in the table, LC1 is the voltage holding ratio of the liquid crystal cell after the normal liquid crystal is injected, and LC2 is the voltage holding ratio of the liquid crystal cell in which the impurity is mixed into the liquid crystal.

[industrial use]

The liquid crystal alignment film produced by using the liquid crystal alignment agent of the present invention is particularly useful for a liquid crystal display element of an IPS driving method or an FFS driving method, and the liquid crystal display element of the present invention is used for a multi-function mobile phone (smart phone), lithography Personal computers, LCD TVs, etc. are especially useful.

The scope, drawings, and abstracts of Japanese Patent Application No. 2014-020435, filed on Jan. 5, 2014, the entire disclosure of which is hereby incorporated by reference.

Claims (10)

A liquid crystal alignment agent 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, R is an alkyl group having 1 to 5 carbon atoms, and A ₁ and A ₂ each independently represent a hydrogen atom, or may be An alkyl group, an alkenyl group or an alkynyl group having 1 to 10 carbon atoms having a substituent, and the divalent organic group represented by the formula (2) is 1 to 99 mols based on the entire Y ₁ in the formula (1). %), (In the formula (2), D is a group having a carbon number of 1 to 20 selected from a group consisting of a saturated hydrocarbon group, an unsaturated hydrocarbon group, an aromatic hydrocarbon group, and a heterocyclic ring, and these may have a substituent, m Is 1 or 0). The liquid crystal alignment agent of claim 1, wherein the divalent organic group represented by the formula (2) in the formula (1) is a carbon number in the formula (2) A 2 to 20-chain chain or cyclic alkyl group. The liquid crystal alignment agent of claim 1 or 2, wherein Y ₁ in the formula (1) is a divalent organic group represented by the formula (2), and the structure Y-7 represented by the following formula At least one selected from the group consisting of Y-21, Y-28, Y-71, Y-72, and Y-119 The liquid crystal alignment agent of claim 1 or 2, wherein each of A ₁ and A ₂ independently represents a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent, and any of them is a hydrogen atom. The liquid crystal alignment agent of claim 1 or 2, wherein X ₁ in the formula (1) is at least one selected from the group consisting of the structures represented by the following formulas, The liquid crystal alignment agent of claim 1 or 2, wherein the organic solvent is N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide , N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methyl caprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, two a group of methyl sulfonium, dimethyl hydrazine, γ-butyrolactone, 1,3-dimethyl-tetrahydroimidazolidone, and 3-methoxy-N,N-dimethylpropane decylamine One or two or more selected ones. The liquid crystal alignment agent according to claim 1 or 2, which contains the other polymer together with the polyamic acid ester, and the polyacetamide has a content of 5 to 95% by mass based on the total polymer. A liquid crystal alignment film obtained by applying the liquid crystal alignment agent according to any one of claims 1 to 7 to a substrate and sintering it at 150 to 300 °C. A liquid crystal display element comprising the liquid crystal alignment film of claim 8. The liquid crystal display element of claim 9, wherein the liquid crystal molecules which are parallel-aligned with respect to the substrate are driven by a lateral electric field.