JP5413556B2 - Liquid crystal aligning agent, method for forming liquid crystal aligning film, and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal alignment agent, a method for forming a liquid crystal alignment film, and a liquid crystal display element.

Conventionally, a nematic liquid crystal having positive dielectric anisotropy is sandwiched with a substrate with a transparent electrode having a liquid crystal alignment film, and the major axis of the liquid crystal molecules is continuously twisted between 0 and 360 ° between the substrates as necessary. There are known liquid crystal display elements having liquid crystal cells such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, and IPS (In Plane Switching) type (see Patent Documents 1 and 2). .
In such a liquid crystal cell, it is necessary to provide a liquid crystal alignment film on the substrate surface in order to align liquid crystal molecules in a predetermined direction with respect to the substrate surface. This liquid crystal alignment film is usually formed by a method (rubbing method) in which the organic film surface formed on the substrate surface is rubbed in one direction with a cloth material such as rayon. However, when the liquid crystal alignment film is formed by a rubbing process, dust and static electricity are likely to be generated in the process, so that there is a problem that dust adheres to the alignment film surface and causes display defects. In particular, in the case of a substrate having a TFT (Thin Film Transistor) element, there has been a problem that the circuit damage of the TFT element occurs due to the generated static electricity, resulting in a decrease in yield. Furthermore, in liquid crystal display elements that will be further refined in the future, unevenness is generated on the substrate surface as the density of pixels increases, and it is becoming difficult to perform rubbing treatment uniformly.
As another means of aligning the liquid crystal in the liquid crystal cell, light that imparts liquid crystal alignment ability by irradiating polarized or non-polarized radiation to a photosensitive thin film such as polyvinyl cinnamate, polyimide, or azobenzene derivative formed on the substrate surface. Orientation methods are known. According to this method, uniform liquid crystal alignment can be realized without generating static electricity or dust (see Patent Documents 3 to 13).
By the way, in a liquid crystal cell of TN (Twisted Nematic) type, STN (Super Twisted Nematic) type or the like, the liquid crystal alignment film needs to have a pretilt angle characteristic that tilts liquid crystal molecules at a predetermined angle with respect to the substrate surface. There is. In the case of forming a liquid crystal alignment film by the photo-alignment method, the pretilt angle is usually given by tilting the incident direction of the irradiated radiation to the substrate surface from the substrate normal.

On the other hand, a vertical alignment mode VA (Vertical Alignment) type liquid crystal cell in which liquid crystal molecules having negative dielectric anisotropy are aligned perpendicularly to a substrate is also known as an operation mode of a liquid crystal display element different from the above. It has been. In this operation mode, when a voltage is applied between the substrates and the liquid crystal molecules are tilted in the direction parallel to the substrate, the liquid crystal molecules must be tilted from the substrate normal direction to one direction in the substrate surface. There is. As a means for this, for example, a method of providing protrusions on the substrate surface, a method of providing stripes on the transparent electrode, or using a rubbing alignment film, liquid crystal molecules are slightly directed from the substrate normal direction to one direction in the substrate surface. A method of tilting (pretilting) has been proposed.
The photo-alignment method is known to be useful as a method for controlling the tilt direction of liquid crystal molecules in a vertical alignment mode liquid crystal cell. That is, it is known that the tilt direction of liquid crystal molecules at the time of voltage application can be uniformly controlled by using a vertical alignment film provided with alignment regulating ability and pretilt angle expression by a photo-alignment method (Patent Documents 11 to 12). And 14-16).
Thus, the liquid crystal alignment film manufactured by the photo-alignment method can be effectively applied to various liquid crystal display elements. However, the conventional photo-alignment film has a problem that a large amount of radiation is required to obtain a large pretilt angle. For example, when a liquid crystal alignment ability is imparted to a thin film containing an azobenzene derivative by a photo-alignment method, in order to obtain a sufficient pretilt angle, radiation whose optical axis is inclined from the substrate normal is 10,000 J / m ² or more It has been reported that it must be irradiated (see Patent Documents 13 to 14 and Non-Patent Document 1).
JP 56-91277 A JP-A-1-120528 JP-A-6-287453 JP-A-10-251646 Japanese Patent Laid-Open No. 11-2815 JP-A-11-152475 JP 2000-144136 A JP 2000-319510 A JP 2000-281724 A JP-A-9-297313 JP 2003-307736 A JP 2004-163646 A JP 2002-250924 A JP 2004-83810 A Japanese Patent Laid-Open No. 9-21468 JP 2003-114437 A JP-A 63-291922 T. T. et al. J. et al. Scheffer et. al. J. et al. Appl. Phys. vo. 19, p2013 (1980)

  An object of the present invention is to provide a liquid crystal aligning agent that provides a liquid crystal aligning film having a good liquid crystal aligning ability even with a small exposure amount by irradiation with polarized or non-polarized radiation without rubbing, a method for producing the liquid crystal aligning film, and a display An object of the present invention is to provide a liquid crystal display element excellent in various performances such as characteristics and reliability.

According to the present invention, the above objects and advantages of the present invention are as follows.
Following formula (1)

(In Formula (1), A is a single bond, a methylene group, or a C2-C6 alkylene group.)
It achieves by the liquid crystal aligning agent containing the reaction product of the polymer which has a repeating unit represented by these, and a cinnamic acid derivative which has a carboxyl group.
The above objects and advantages of the present invention are secondly,
This is achieved by a method for forming a liquid crystal alignment film in which the liquid crystal aligning agent is applied onto a substrate to form a coating film, and the coating film is irradiated with radiation.
Further, the above object and advantage of the present invention are as follows.
This is achieved by a liquid crystal display element comprising a liquid crystal alignment film formed from the above liquid crystal aligning agent.

  The liquid crystal aligning agent of the present invention is a liquid crystal aligning film having excellent liquid crystal aligning properties and electrical characteristics with a small radiation dose as compared with a liquid crystal aligning agent conventionally known as a liquid crystal aligning agent to which a photo-alignment method can be applied. Can be formed. Therefore, when this liquid crystal alignment film is applied to a liquid crystal display element, the liquid crystal display element can be manufactured at a lower cost than before, and the various properties such as display characteristics and reliability are excellent. Therefore, these liquid crystal display elements can be effectively applied to various devices, and can be suitably used for devices such as desk calculators, watches, table clocks, counting display boards, word processors, personal computers, and liquid crystal televisions.

Hereinafter, the present invention will be described in detail.
The liquid crystal aligning agent of the present invention is a reaction product of a polymer having a repeating unit represented by the above formula (1) (hereinafter referred to as “polymer having an epoxy group”) and a cinnamic acid derivative having a carboxyl group. Product (hereinafter referred to as “polymer having a cinnamic acid skeleton”).
<Polymer having epoxy group>
A in the formula (1) is preferably a methylene group or an alkylene group having 2 to 6 carbon atoms, and more preferably a methylene group.
The following formula in the above formula (1)

The bonding position of the group represented by
The polymer having an epoxy group may have only the repeating unit represented by the above formula (1), or may have other repeating units in addition to the repeating unit represented by the above formula (1). However, it is preferable to have only the repeating unit represented by the above formula (1). The polystyrene-converted weight average molecular weight of the polymer having an epoxy group measured by gel permeation chromatography is preferably 1,000 to 10,000, and more preferably 1,500 to 4,000.
The epoxy equivalent of the polymer having an epoxy group is preferably 100 to 1,000 g / mol, more preferably 120 to 250 g / mol.
The terminal structure of the polymer having an epoxy group is not limited. For example, the left end of the above formula (1) is an alkoxyl group or a hydroxyalkoxyl group having 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms. The terminal of can be a hydrogen atom. Examples of the hydroxyalkoxyl group include the following formula (1a)

The group represented by these can be mentioned.
A commercially available product may be used as the polymer having an epoxy group. Examples of such commercially available products include EHPE3150 and EHPE3150CE (manufactured by Daicel Chemical Industries, Ltd.).
<Cinnamic acid derivative having a carboxyl group>
Examples of the cinnamic acid derivative having a carboxyl group include the following formulas (2) to (5).

(In the formula (2), R ¹ is a monovalent organic group having 3 to 40 carbon atoms containing a hydrogen atom, an alkyl group or an alicyclic group having 1 to 40 carbon atoms, said alkyl group or an alicyclic group A part or all of the hydrogen atoms may be substituted with a fluorine atom, R ² is a single bond, an oxygen atom, —COO— or —OCO—, R ³ is a divalent aromatic group, divalent An alicyclic group, a divalent heterocyclic group or a divalent condensed cyclic group, R ⁴ is a single bond, an oxygen atom, —COO— or —OCO—, and R ⁵ is a fluorine atom or a cyano group A is an integer of 0 to 3, and b is an integer of 0 to 4.)

(In the formula (3), R ⁶ is a monovalent organic group having 3 to 40 carbon atoms including an alkyl group having 1 to 40 carbon atoms or an alicyclic group, and a hydrogen atom of the alkyl group or alicyclic group. May be substituted with a fluorine atom, R ⁷ is a single bond or a divalent organic group, R ⁸ is a fluorine atom or a cyano group, and c is an integer of 0 to 4. .)

(In the formula (4), R ⁹ is a monovalent organic group having 3 to 40 carbon atoms containing an alkyl group or an alicyclic group having 1 to 40 carbon atoms, hydrogen atoms of the alkyl group or an alicyclic group A part or all of may be substituted with a fluorine atom, and R ¹⁰ is a single bond, an oxygen atom, a sulfur atom or ^* —COO— (wherein a bond with “*” is bonded to R ⁹ . R ¹¹ is a hydrogen atom, or R ¹⁰ and R ¹¹ may be bonded to each other to form a ring, R ¹² is a fluorine atom or a cyano group, and d is 0-4. (It is an integer.)

(In the formula (5), R ¹³ is a divalent organic group and R ¹⁴ is a hydrogen atom or a monovalent organic group, or R ¹³ and R ¹⁴ are bonded to each other to form a ring. R ¹⁵ is a fluorine atom or a cyano group, and R ¹⁶ is an alkyl group having 1 to 20 carbon atoms that may be substituted with a fluorine atom, or 3 to 40 carbon atoms that may be substituted with a fluorine atom. (It is an alicyclic group, and e is an integer of 0 to 4.)
The compound represented by each of these can be mentioned.
As the alkyl group having 1 to 40 carbon atoms of R ¹ in the above formula (2), for example, an alkyl group having 1 to 20 carbon atoms, provided that part or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms. It is preferable that Examples of such alkyl groups include, for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n -Decyl group, n-lauryl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n -Eicosyl group, 4,4,4-trifluorobutyl group, 4,4,5,5,5-pentafluoropentyl, 4,4,5,5,6,6,6-heptafluorohexyl group, 3, 3,4,4,5,5,5-heptafluoropentyl group, 2,2,2-trifluoroethyl group, 2,2,3,3,3-pentafluoropropyl group, 2- (perfluorobutyl) Ethyl group, 2- Perfluorooctyl) ethyl group, 2- (perfluoro decyl) ethyl group and the like. The monovalent organic group having 3 to 40 carbon atoms containing an alicyclic group R ^1, may include, for example Koresuteniru group, cholestanyl group, an adamantyl group.

Examples of the divalent aromatic group for R ³ include 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 2,3,5,6- A tetrafluoro-1,4-phenylene group or the like; examples of the divalent heterocyclic group represented by R ³ include a 1,4-pyridylene group, a 2,5-pyridylene group, and a 1,4-furanylene group; Examples of the divalent condensed cyclic group of ^3, for example, 2,6-naphthylene group, can be exemplified respectively. R ³ is preferably a 1,4-phenylene group.
As R ⁴ , ^* —COO— (however, a bond marked with “*” is bonded to the R ¹ side) is preferable.
R ⁵ is preferably a fluorine atom. a is preferably 0 or 1, and b is preferably 0 or 1.
Preferable examples of the compound represented by the above formula (2) include, for example, the following formulas (2-1) to (2-8):

(In the above formula, each R ¹ has the same meaning as in the above formula (2).)
The compound etc. which are represented by each of these can be mentioned.
The compound represented by the above formula (2) can be synthesized by appropriately combining organic chemistry methods.
For example, the compound represented by the above formula (2-1) can be reacted with, for example, hydroxycinnamic acid and an alcohol having an alkyl group corresponding to R ¹ by heating in the presence of a suitable base such as potassium carbonate. It can be obtained by hydrolysis with a suitable alkaline aqueous solution such as sodium hydroxide.
The compound represented by the above formula (2-2) is prepared by reacting, for example, hydroxycinnamic acid and an alkylcarboxylic acid chloride having an alkyl group corresponding to R ¹ in the presence of a suitable base such as potassium carbonate at a temperature of 0 ° C. to room temperature. It can obtain by making it react.
The compound represented by the above formula (2-4) is, for example, methyl hydroxybenzoate and an alkyl halide having an alkyl group corresponding to R ¹ or a tosylated alkyl in the presence of a suitable base such as potassium carbonate at room temperature to After reacting at a temperature of 100 ° C., the mixture is hydrolyzed with an appropriate alkaline aqueous solution such as sodium hydroxide, and further converted into an acid chloride with thionyl chloride, which is then treated with hydroxy in the presence of an appropriate base such as potassium carbonate. It can be obtained by reacting with cinnamic acid at a temperature of 0 ° C. to room temperature.
The compound represented by the above formula (2-5) is, for example, a hydroxybenzoic acid and an alkylcarboxylic acid chloride having an alkyl group corresponding to R ¹ in the presence of a suitable base such as triethylamine at a temperature of 0 ° C. to room temperature. After the reaction, acid chloride is obtained with thionyl chloride, which can be obtained by reacting with hydroxycinnamic acid in the presence of a suitable base such as potassium carbonate at a temperature of 0 ° C. to room temperature.

The compound represented by the above formula (2-6) is obtained by, for example, converting the compound represented by the above formula (2-3) into an acid chloride with thionyl chloride, and then subjecting this to hydroxy in the presence of a suitable base such as potassium carbonate. It can be obtained by reacting with cinnamic acid at a temperature of 0 ° C. to room temperature.
The compound represented by the above formula (2-7) is obtained by, for example, methyl 4-hydroxycyclohexylbenzoate and an alkyl halide having an alkyl group corresponding to R ¹ in the presence of a suitable alkali such as sodium hydride or sodium metal. The reaction is carried out under reduced pressure to obtain an ether, hydrolyzed with an aqueous alkali solution such as sodium hydroxide, and further converted into acid chloride with thionyl chloride, which is then treated with hydroxycinnamic acid in the presence of a suitable base such as potassium carbonate. It can obtain by making it react at the temperature of (degreeC)-room temperature.
In the compound represented by the above formula (2-8), for example, 4-alkylcyclohexylcarboxylic acid having an alkyl group corresponding to R ¹ is converted to acid chloride with thionyl chloride in the presence of a suitable base such as potassium carbonate. Can be obtained by reacting with hydroxycinnamic acid at a temperature of 0 ° C. to room temperature.
R ⁶ in the above formula (3) is the same as that described for R ¹ in the above formula (2). As the divalent organic group for R ⁷ , for example, ^* —OCO— (CH ₂ ) _g — (however, a bond marked with “*” is bonded to a benzene ring, and g is an integer of 1 to 10. And the like. R ⁸ is preferably a fluorine atom. c is preferably 0, 1 or 4.
Preferable examples of the compound represented by the above formula (3) include, for example, the following formula (3-1)

(In formula (3-1), R ⁶ has the same meaning as in formula (3) above, and g is the same as in the description of R ⁷ above.)
The compound represented by these can be mentioned.
The compound represented by the above formula (3-1) reacts, for example, 4-iodophenol and an alkyl acrylate having an alkyl group corresponding to R ⁶ using palladium and an amine as a catalyst (generally referred to as “Heck reaction”). ) And then ring opening addition of a desired cyclic acid anhydride such as succinic anhydride or glutaric anhydride to the reaction product.
R ⁹ in the above formula (4) is the same as that described for R ¹ in the above formula (2). The ring formed by combining R ¹⁰ and R ¹¹ includes a monocyclic ring, a polycyclic ring, a condensed ring, and a bridged ring. A ring having 4 to 8 carbon atoms is preferable. Specific examples include a cyclobutane ring and a cyclopentane. A ring, a cyclohexane ring, a norbornene ring, etc. can be mentioned. R ¹² is preferably a fluorine atom. d is preferably 0, 1 or 4.
Preferred examples of the compound represented by the above formula (4) include, for example, the following formulas (4-1) to (4-5):

(In the above formula, R ⁹ has the same meaning as in the above formula (4), R ^9-1 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ^9-2 is 1-7. An alkyl group having 3 to 10 carbon atoms substituted with one fluorine atom.)
The compound etc. which are represented by each of these can be mentioned.
R ⁹ in the above formula (4-3) or (4-4) is preferably an alkyl group having 1 to 20 carbon atoms which may be substituted with a fluorine atom.
The compound represented by the above formula (4-1) can be obtained, for example, by reacting an alkyl succinic anhydride having an alkyl group corresponding to R ^9-1 with 4-aminocinnamic acid. This reaction can be carried out, for example, by refluxing the starting compound in acetic acid or refluxing in toluene or xylene in the presence of a suitable base catalyst such as triethylamine.
The compound represented by the above formula (4-2) is obtained by coupling, for example, 4,4,4-trifluoro-1-iodobutane and maleic anhydride protected with a suitable protecting group such as p-toluidine by a Grignard reaction. Then, deprotection and dehydration ring closure are carried out, and the product can be obtained by reacting with 4-aminocinnamic acid in the same manner as in the synthesis of the compound represented by the above formula (4-1).

The compound represented by the above formula (4-3) can be synthesized, for example, by one of the following two routes.
As a first route, maleic anhydride is protected with an appropriate protecting group such as p-toluidine, and an alcohol having an alkyl group corresponding to R ⁹ is added with Michael in the presence of an appropriate base with potassium carbonate. , Deprotection by hydrolysis, dehydration ring closure, and reaction of the product with 4-aminocinnamic acid in the same manner as in the synthesis of the compound represented by the above formula (4-1). be able to.
As a second route, methyl malate and an alkyl halide having an alkyl group corresponding to R ⁹ are reacted with each other in the presence of silver oxide to form an ether, followed by hydrolysis, dehydration ring closure, A method of reacting the product with 4-aminocinnamic acid in the same manner as in the synthesis of the compound represented by the above formula (4-1) can be mentioned.
The compound represented by the formula (4-4), for example in addition the above expressions with thiols in place of alcohol having an alkyl group having an alkyl group corresponding to R ^9, which corresponds to R ⁹ (4-3) It can be obtained in the same manner as in the first route in the synthesis of the compound represented by
The compound represented by the above formula (4-5) is, for example, an alcohol having an alkyl group corresponding to R ⁹ and triethylamine after 1,2,4-tricarboxycyclohexane anhydride is converted to acid chloride with thionyl chloride. It can be obtained by reacting in the presence of a suitable base for esterification and reacting the product with 4-aminocinnamic acid in the same manner as in the synthesis of the compound represented by the above formula (4-1). it can.

Specific examples of R ¹⁶ in the above formula (5) include, for example, a methyl group, ethyl group, n-propyl, n-butyl group, n- Pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-lauryl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n- Pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosyl group, 4,4,4-trifluorobutyl group, 4,4,5,5,5-penta Fluoropentyl, 4,4,5,5,6,6,6-heptafluorohexyl group, 3,3,4,4,5,5,5-heptafluoropentyl group, 2,2,2-trifluoroethyl Group 2,2,3 , 3,3-pentafluoropropyl group, 2- (perfluorobutyl) ethyl group, 2- (perfluorooctyl) ethyl group, 2- (perfluorodecyl) ethyl group and the like; may be substituted with fluorine Examples of the alicyclic group having 3 to 40 carbon atoms include a cholestenyl group, a cholestanyl group, and an adamantyl group.
Preferred examples of the compound represented by the above formula (5) include, for example, the following formula (5-1)

(In the above formula, R ¹⁶ has the same meaning as in the above formula (5).)
The compound etc. which are represented by these can be mentioned.
The compound represented by the above formula (5-1) is, for example, 4-nitrocinnamic acid converted to an acid chloride with thionyl chloride, then reacted with an alcohol having an alkyl group corresponding to R ¹⁶ to form an ester, and the nitro group Can be obtained by reacting the product with 1,2,4-tricarboxycyclohexylcyclohexane anhydride after reduction to, for example, tin chloride to form an amino group. The latter reaction can be carried out, for example, by refluxing the starting compound in acetic acid or refluxing in toluene or xylene in the presence of a suitable base catalyst such as triethylamine.

<Polymer having cinnamic acid skeleton>
The polymer having a cinnamic acid skeleton contained in the liquid crystal aligning agent of the present invention is preferably an appropriate polymer having an epoxy group and a cinnamic acid derivative having a carboxyl group, preferably in the presence of a catalyst. It can be synthesized by reacting in an organic solvent.
The ratio of the cinnamic acid derivative having a carboxyl group used in the reaction is preferably 0.001 to 1.5 mol, more preferably 1 mol with respect to 1 mol of the epoxy group contained in the polymer having an epoxy group. It is 0.01-1 mol, More preferably, it is 0.05-0.9 mol.
As the catalyst that can be used here, a compound known as a so-called curing accelerator that accelerates the reaction between an organic base or an epoxy compound and an acid anhydride can be used.
Examples of the organic base include primary and secondary organic amines such as ethylamine, diethylamine, piperazine, piperidine, pyrrolidine, and pyrrole;
Tertiary organic amines such as triethylamine, tri-n-propylamine, tri-n-butylamine, pyridine, 4-dimethylaminopyridine, diazabicycloundecene;
A quaternary organic amine such as tetramethylammonium hydroxide can be used. Among these organic bases, tertiary organic amines such as triethylamine, tri-n-propylamine, tri-n-butylamine, pyridine and 4-dimethylaminopyridine; quaternary organic amines such as tetramethylammonium hydroxide preferable.

Examples of the curing accelerator include tertiary amines such as benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, cyclohexyldimethylamine, and triethanolamine;
2-methylimidazole, 2-n-heptylimidazole, 2-n-undecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenyl Imidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1- (2-cyanoethyl) -2-methylimidazole, 1- (2-cyanoethyl) -2-n-undecylimidazole, 1- ( 2-cyanoethyl) -2-phenylimidazole, 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-di (Hydroxymethyl) imidazole, 1- (2-cyanoethyl) -2-fur Nyl-4,5-di [(2′-cyanoethoxy) methyl] imidazole, 1- (2-cyanoethyl) -2-n-undecylimidazolium trimellitate, 1- (2-cyanoethyl) -2-phenyl Imidazolium trimellitate, 1- (2-cyanoethyl) -2-ethyl-4-methylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')] ethyl-s -Triazine, 2,4-diamino-6- (2'-n-undecylimidazolyl) ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1 ' )] Ethyl-s-triazine, isocyanuric acid adduct of 2-methylimidazole, isocyanuric acid adduct of 2-phenylimidazole, 2,4-diamino-6- [2'-methyl] An imidazole compound such as an isocyanuric acid adduct of loumidazolyl- (1 ′)] ethyl-s-triazine;
Organophosphorus compounds such as diphenylphosphine, triphenylphosphine, triphenyl phosphite;

Benzyltriphenylphosphonium chloride, tetra-n-butylphosphonium bromide, methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, n-butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide , Ethyltriphenylphosphonium iodide, ethyltriphenylphosphonium acetate, tetra-n-butylphosphonium o, o-diethylphosphorodithionate, tetra-n-butylphosphonium benzotriazolate, tetra -N-butylphosphonium tetrafluoroborate, tetra-n-butylphosphonium tetraphenylborate, tetraphenylphosphonium tetraphenylborate Such bets quaternary phosphonium salts;
Diazabicycloalkenes such as 1,8-diazabicyclo [5.4.0] undecene-7 and organic acid salts thereof;
Organometallic compounds such as zinc octylate, tin octylate, aluminum acetylacetone complex;
Quaternary ammonium salts such as tetraethylammonium bromide, tetra-n-butylammonium bromide, tetraethylammonium chloride, tetra-n-butylammonium chloride;
Boron compounds such as boron trifluoride and triphenyl borate;
Metal halides such as zinc chloride and stannic chloride;
High melting point dispersion type latent curing accelerators such as amine addition accelerators such as dicyandiamide and adducts of amine and epoxy resin;
A microcapsule-type latent curing accelerator in which the surface of a curing accelerator such as the imidazole compound, organic phosphorus compound or quaternary phosphonium salt is coated with a polymer;
An amine salt type latent curing agent accelerator;
Examples include latent curing accelerators such as high-temperature dissociation type thermal cationic polymerization type latent curing accelerators such as Lewis acid salts and Bronsted acid salts.
Of these, quaternary ammonium salts such as tetraethylammonium bromide, tetra-n-butylammonium bromide, tetraethylammonium chloride, and tetra-n-butylammonium chloride are preferable.

The proportion of the catalyst used is preferably 100 parts by weight or less, more preferably 0.01 to 100 parts by weight, still more preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the polymer having an epoxy group. It is.
Examples of the organic solvent include hydrocarbon compounds, ether compounds, ester compounds, ketone compounds, amide compounds, alcohol compounds, and the like. Of these, ether compounds, ester compounds, and ketone compounds are preferred from the viewpoints of solubility of raw materials and products and ease of purification of the products. The solvent is used in such an amount that the solid content concentration (the ratio of the weight of components other than the solvent in the reaction solution to the total weight of the solution) is preferably 0.1% by weight or more, more preferably 5 to 50% by weight. Is done.
The reaction temperature is preferably 0 to 200 ° C, more preferably 50 to 150 ° C. The reaction time is preferably 0.1 to 50 hours, more preferably 0.5 to 20 hours.
In this way, a solution containing a polymer having a cinnamic acid skeleton is obtained. This solution may be used as it is for the preparation of the liquid crystal aligning agent, may be used for the preparation of the liquid crystal aligning agent after isolating the polymer contained in the solution, or after the isolated polymer is purified. You may use for preparation of a liquid crystal aligning agent.

<Other ingredients>
The liquid crystal aligning agent of the present invention contains a polymer having a cinnamic acid skeleton as described above.
The liquid crystal aligning agent of the present invention may further contain other components in addition to the polymer having a cinnamic acid skeleton as described above as long as the effects of the present invention are not impaired. Examples of such other components include polymers other than polymers having a cinnamic acid skeleton (hereinafter referred to as “other polymers”), compounds having at least one epoxy group in the molecule (hereinafter referred to as “epoxy”). Compound "), functional silane compounds, surfactants, and the like.
Said other polymer can be used in order to improve the solution characteristic of the liquid crystal aligning agent of this invention, and the electrical property of the liquid crystal aligning film obtained. Examples of such other polymers include at least one polymer selected from the group consisting of polyamic acid and polyimide, polysiloxane, polyamic acid ester, polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene- Phenylmaleimide) derivatives, poly (meth) acrylates and the like.
The polyamic acid can be obtained by reacting tetracarboxylic dianhydride with a diamine compound.
Examples of tetracarboxylic dianhydrides that can be used for the synthesis of polyamic acid include 2,3,5-tricarboxycyclopentylacetic acid dianhydride, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutane. Tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 3,5, 6-tricarboxynorbornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2, 5-Dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydride) -2,5-dioxo-3-furanyl) -8-methyl-naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofuranyl) -3-methyl- 3-cyclohexene-1,2-dicarboxylic anhydride, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, the following formula (T-1) ~ (T-4)

An aliphatic or alicyclic tetracarboxylic dianhydride such as tetracarboxylic dianhydride represented by each of
Pyromellitic dianhydride, 3,3 ′, 4,4′-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7- Naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ', 4,4'-Tetraphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfide Dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′ , 4 4′-perfluoroisopropylidenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis ( Triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenyl ether dianhydride, bis (triphenylphthalic acid)- 4,4′-diphenylmethane dianhydride, the following formulas (T-5) to (T-8)

An aromatic tetracarboxylic dianhydride such as tetracarboxylic dianhydride represented by each of the above. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.
The tetracarboxylic dianhydride used to synthesize polyamic acid is 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl among the above. ) -Naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -8 -Methyl-naphtho [1,2-c] -furan-1,3-dione, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, butanetetracarboxylic dianhydride, 1,3-dimethyl-1, 2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenylsulfonetetra Carboxylic acid Water, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic acid At least one selected from the group consisting of a dianhydride and a tetracarboxylic dianhydride represented by each of the above formulas (T-1), (T-2) and (T-5) to (T-8) It is preferable that it contains a seed, and it is more preferable that at least one of these is included in an amount of 20 mol% or more, more preferably 50 mol% or more, based on the total tetracarboxylic dianhydride, In particular, it is preferable to contain 80 mol% or more.

  Examples of diamines that can be used for the synthesis of polyamic acid include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3, 3-dimethyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4′-aminophenyl) -1 , 3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 2,2-bis (4-a Nophenoxy) propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4 -Aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) Benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) Fluorene, 4,4'-methylene-bis (2-chloroaniline), 2,2 ', 5,5'-tetrachloro-4,4'-diaminobipheny 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 4,4 ′-(p-phenyleneisopropylidene) Bisaniline, 4,4 ′-(m-phenyleneisopropylidene) bisaniline, 2,2-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2 , 2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl,

6- (4-Calconyloxy) hexyloxy (2,4-diaminobenzene), 6- (4′-fluoro-4-chalconyloxy) hexyloxy (2,4-diaminobenzene), 8- (4- Calconyloxy) octyloxy (2,4-diaminobenzene), 8- (4′-fluoro-4-calconyloxy) octyloxy (2,4-diaminobenzene), 1-dodecyloxy-2,4-diamino Benzene, 1-tetradecyloxy-2,4-diaminobenzene, 1-pentadecyloxy-2,4-diaminobenzene, 1-hexadecyloxy-2,4-diaminobenzene, 1-octadecyloxy-2,4- Diaminobenzene, 1-cholesteryloxy-2,4-diaminobenzene, 1-cholestanyloxy-2,4-diaminobenzene, Decyloxy (3,5-diaminobenzoyl), tetradecyloxy (3,5-diaminobenzoyl), pentadecyloxy (3,5-diaminobenzoyl), hexadecyloxy (3,5-diaminobenzoyl), octadecyloxy (3 , 5-diaminobenzoyl), cholesteryloxy (3,5-diaminobenzoyl), cholestanyloxy (3,5-diaminobenzoyl), (2,4-diaminophenoxy) palmitate, (2,4-diaminophenoxy) stearylate , (2,4-diaminophenoxy) -4-trifluoromethylbenzoate, the following formulas (D-1) to (D-7)

(Y in the formula (D-4) is an integer of 2 to 12, and z in the formula (D-5) is an integer of 1 to 5.)
An aromatic diamine such as a diamine compound represented by each of
Aromatic diamines having hetero atoms such as diaminotetraphenylthiophene; metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoin danylenediethylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyl diamine, aliphatic or cycloaliphatic diamines such as 4,4'-methylenebis (cyclohexylamine);
Examples include diaminoorganosiloxanes such as diaminohexamethyldisiloxane.
In the aromatic diamine, the benzene ring may be substituted with one or two or more alkyl groups having 1 to 4 carbon atoms (preferably a methyl group).
These diamines can be used alone or in combination of two or more.

  Among the above, the diamine used for synthesizing the polyamic acid is p-phenylenediamine, 4,4′-diaminodiphenylmethane, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4′-diamino. Diphenyl ether, 4,4 ′-(p-phenyleneisopropylidene) bisaniline, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane 2,2-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4 '-Bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluoro Phenyl, 1-hexadecyloxy-2,4-diaminobenzene, 1-octadecyloxy-2,4-diaminobenzene, 1-cholesteryloxy-2,4-diaminobenzene, 1-cholestanyloxy-2,4-diamino Benzene, hexadecyloxy (3,5-diaminobenzoyl), octadecyloxy (3,5-diaminobenzoyl), cholesteryloxy (3,5-diaminobenzoyl), cholestanyloxy (3,5-diaminobenzoyl) and the above formula It is preferable that it contains at least one selected from the group consisting of the compounds represented by each of (D-1) to (D-7), and at least one of these is based on the total diamine. More preferably, the content is more than 20 mol%, and more than 50 mol%. But more preferably, it is preferable that in particular include over 80 mol%.

The proportion of tetracarboxylic dianhydride and diamine used in the polyamic acid synthesis reaction is such that the acid anhydride group of the tetracarboxylic dianhydride is 0.2 to 1 equivalent to 1 equivalent of an amino group contained in the diamine. A ratio of 2 equivalents is preferable, and a ratio of 0.3 to 1.2 equivalents is more preferable.
The polyamic acid synthesis reaction is preferably performed in an organic solvent, preferably at a temperature of −20 to 150 ° C., more preferably at a temperature of 0 to 100 ° C., preferably 0.5 to 24 hours, more preferably 2 to 10 Done for hours. Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, N, Aprotic polar solvents such as N-dimethylimidazolidinone, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphoric triamide; and phenolic solvents such as m-cresol, xylenol, phenol, halogenated phenol Can do. The amount (a) of the organic solvent used is such that the total amount (b) of tetracarboxylic dianhydride and diamine compound is preferably 0.1 to 50% by weight, more preferably 5 to 5%, based on the total amount (a + b) of the reaction solution. The amount is 30% by weight.
As described above, a reaction solution obtained by dissolving polyamic acid is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution, or the isolated polyamic acid was purified. You may use for preparation of a liquid crystal aligning agent. Polyamic acid can be isolated by pouring the reaction solution into a large amount of poor solvent to obtain a precipitate, and drying the precipitate under reduced pressure, or by distilling the reaction solution under reduced pressure using an evaporator. it can. Further, the polyamic acid can be purified by a method of dissolving the polyamic acid again in an organic solvent and then precipitating with a poor solvent, or a method of performing the step of distilling under reduced pressure with an evaporator once or several times.

The polyimide can be produced by dehydrating and ring-closing the amic acid structure of the polyamic acid obtained as described above. At this time, all of the amic acid structure may be dehydrated and closed to completely imidize, or only a part of the amic acid structure may be dehydrated and closed to form a partially imidized product in which the amic acid structure and the imide structure coexist. Also good.
The polyamic acid is dehydrated and closed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to this solution, and heating as necessary. By the method.
The reaction temperature in the method of heating the polyamic acid (i) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C., the dehydration ring-closing reaction does not proceed sufficiently, and when the reaction temperature exceeds 200 ° C., the molecular weight of the imidized polymer obtained may decrease. The reaction time in the method of heating the polyamic acid is preferably 0.5 to 48 hours, more preferably 2 to 20 hours.
On the other hand, in the method (ii) of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride is used as the dehydrating agent. Can do. The amount of the dehydrating agent used is preferably 0.01 to 20 mol with respect to 1 mol of the polyamic acid structural unit. Moreover, as a dehydration ring closure catalyst, tertiary amines, such as a pyridine, a collidine, a lutidine, a triethylamine, can be used, for example. However, it is not limited to these. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C., more preferably 10 to 150 ° C., and the reaction time is preferably 0.5 to 20 hours, more preferably 1 to 8 hours.
The polyimide obtained in the above method (i) may be used for the preparation of the liquid crystal aligning agent as it is, or may be used for the preparation of the liquid crystal aligning agent after purifying the obtained polyimide. On the other hand, in the above method (ii), a reaction solution containing polyimide is obtained. This reaction solution may be used as it is for the preparation of a liquid crystal aligning agent, or may be used for the preparation of a liquid crystal aligning agent after removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution. It may be used for the preparation of a liquid crystal aligning agent or may be used for the preparation of a liquid crystal aligning agent after purifying the isolated polyimide. In order to remove the dehydrating agent and the dehydration ring closure catalyst from the reaction solution, for example, a method such as solvent replacement can be applied. The isolation and purification of the polyimide can be performed by performing the same operation as described above as the isolation and purification method of the polyamic acid.

  The polysiloxane is, for example, the following formula (α)

(In the formula (α), X is a hydroxyl group, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms, and Y is a hydroxyl group or 1 carbon atom. ˜6 alkoxyl groups.)
It is at least 1 sort (s) selected from the group which consists of polysiloxane which has a repeating unit represented by these, its hydrolyzate, and a hydrolysis condensate.
The polysiloxane is, for example, at least one silane compound selected from the group consisting of an alkoxysilane compound and a halogenated silane compound (hereinafter also referred to as “raw silane compound”), preferably in a suitable organic solvent. It can be synthesized by hydrolysis or hydrolysis / condensation in the presence of water and a catalyst.
Examples of the raw material silane compound that can be used here include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-iso-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, and tetra-tert-. Butoxysilane, tetrachlorosilane; methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltri-iso-propoxysilane, methyltri-n-butoxysilane, methyltri-sec-butoxysilane, methyltri-tert-butoxysilane , Methyltriphenoxysilane, methyltrichlorosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n-propoxysilane, ethyltri-iso-propoxy Lan, ethyltri-n-butoxysilane, ethyltri-sec-butoxysilane, ethyltri-tert-butoxysilane, ethyltrichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrichlorosilane; dimethyldimethoxysilane, dimethyldiethoxysilane, Examples include dimethyldichlorosilane; trimethylmethoxysilane, trimethylethoxysilane, and trimethylchlorosilane. Of these, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane or trimethylethoxysilane are preferred.
The polysiloxane has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography, preferably 500 to 50,000, more preferably 1,000 to 10,000.

Examples of the organic solvent that can be optionally used when synthesizing the polysiloxane include alcohol compounds, ketone compounds, amide compounds, ester compounds, and other aprotic compounds. These can be used alone or in combination of two or more.
Examples of the alcohol compound include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n-pentanol, i-pentanol, 2-methylbutanol, sec-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, heptanol-3, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethylheptanol-4, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol , Phenol, cyclohexanol, methyl cyclohexanol, 3,3,5-trimethyl cyclohexanol, benzyl alcohol, monoalcohol compounds such as diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, pentanediol-2,4, 2-methylpentanediol-2,4, hexanediol-2,5, heptanediol-2,4, 2- Polyhydric alcohol compounds such as ethylhexanediol-1,3, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, the partial ethers of polyhydric alcohol compound and dipropylene glycol monopropyl ether, can be mentioned, respectively. These alcohol compounds may be used alone or in combination of two or more.

Examples of the ketone compound include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, and methyl-n-. Monoketone compounds such as hexyl ketone, di-i-butyl ketone, trimethylnonanone, cyclohexanone, 2-hexanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, acetophenone, fencheon;
Acetylacetone, 2,4-hexanedione, 2,4-heptanedione, 3,5-heptanedione, 2,4-octanedione, 3,5-octanedione, 2,4-nonanedione, 3,5-nonanedione, 5 -Methyl-2,4-hexanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 1,1,1,5,5,5-hexafluoro-2,4-heptanedione, etc. The β-diketone compound and the like can be mentioned respectively. These ketone compounds may be used alone or in combination of two or more.
Examples of the amide compound include formamide, N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-ethyl. Acetamide, N, N-diethylacetamide, N-methylpropionamide, N-methylpyrrolidone, N-formylmorpholine, N-formylpiperidine, N-formylpyrrolidine, N-acetylmorpholine, N-acetylpiperidine, N-acetylpyrrolidine, etc. Can be mentioned. These amide compounds may be used alone or in combination of two or more.

  Examples of the ester compound include diethyl carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, acetic acid. i-butyl, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, acetic acid n-nonyl, methyl acetoacetate, ethyl acetoacetate, ethylene acetate monoethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, vinegar Acid diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene Glycol acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-lactate Examples include amyl, diethyl malonate, dimethyl phthalate, and diethyl phthalate. These ester compounds may be used alone or in combination of two or more.

Examples of the other aprotic compounds include acetonitrile, dimethyl sulfoxide, N, N, N ′, N′-tetraethylsulfamide, hexamethylphosphoric triamide, N-methylmorpholone, N-methylpyrrole, N— Ethylpyrrole, N-methyl-Δ3-pyrroline, N-methylpiperidine, N-ethylpiperidine, N, N-dimethylpiperazine, N-methylimidazole, N-methyl-4-piperidone, N-methyl-2-piperidone, N -Methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethyltetrahydro-2 (1H) -pyrimidinone and the like can be mentioned.
Of these solvents, polyhydric alcohol compounds, partial ethers or ester compounds of polyhydric alcohol compounds are particularly preferred.
The amount of water used in the synthesis of the polysiloxane is preferably 0.5 to 100 mol, more preferably 1 to 30 mol, relative to 1 mol of the total amount of alkoxyl groups and halogen atoms of the starting silane compound. Furthermore, it is preferable that it is 1-1.5 mol.

Examples of the catalyst that can be used in the synthesis of the polysiloxane include metal chelate compounds, organic acids, inorganic acids, organic bases, ammonia, alkali metal compounds, and the like.
Examples of the metal chelate compound include triethoxy mono (acetylacetonato) titanium, tri-n-propoxy mono (acetylacetonato) titanium, tri-i-propoxy mono (acetylacetonato) titanium, tri-n- Butoxy mono (acetylacetonato) titanium, tri-sec-butoxy mono (acetylacetonato) titanium, tri-t-butoxy mono (acetylacetonato) titanium, diethoxybis (acetylacetonato) titanium, di- n-propoxy bis (acetylacetonato) titanium, di-i-propoxy bis (acetylacetonato) titanium, di-n-butoxy bis (acetylacetonato) titanium, di-sec-butoxy bis (acetylacetate) Natto) titanium, di-t-butoxy Su (acetylacetonato) titanium, monoethoxy-tris (acetylacetonato) titanium, mono-n-propoxy-tris (acetylacetonato) titanium, mono-i-propoxy-tris (acetylacetonato) titanium, mono-n -Butoxy-tris (acetylacetonato) titanium, mono-sec-butoxy-tris (acetylacetonato) titanium, mono-t-butoxy-tris (acetylacetonato) titanium, tetrakis (acetylacetonato) titanium, triethoxy mono (Ethyl acetoacetate) titanium, tri-n-propoxy mono (ethyl acetoacetate) titanium, tri-i-propoxy mono (ethyl acetoacetate) titanium, tri-n-butoxy mono (ethyl acetoacetate) titanium, tri -S c-butoxy mono (ethyl acetoacetate) titanium, tri-t-butoxy mono (ethyl acetoacetate) titanium, diethoxy bis (ethyl acetoacetate) titanium, di-n-propoxy bis (ethyl acetoacetate) titanium, Di-i-propoxy bis (ethyl acetoacetate) titanium, di-n-butoxy bis (ethyl acetoacetate) titanium, di-sec-butoxy bis (ethyl acetoacetate) titanium, di-t-butoxy bis ( Ethyl acetoacetate) titanium, monoethoxy tris (ethyl acetoacetate) titanium, mono-n-propoxy tris (ethyl acetoacetate) titanium, mono-i-propoxy tris (ethyl acetoacetate) titanium, mono-n-butoxy・ Tris (ethyl aceto Acetate) titanium, mono-sec-butoxy tris (ethyl acetoacetate) titanium, mono-t-butoxy tris (ethyl acetoacetate) titanium, tetrakis (ethyl acetoacetate) titanium, mono (acetylacetonate) tris (ethyl aceto) Titanium chelate compounds such as acetate) titanium, bis (acetylacetonato) bis (ethylacetoacetate) titanium, tris (acetylacetonato) mono (ethylacetoacetate) titanium;

Triethoxy mono (acetylacetonato) zirconium, tri-n-propoxy mono (acetylacetonato) zirconium, tri-i-propoxy mono (acetylacetonato) zirconium, tri-n-butoxy mono (acetylacetonate) Zirconium, tri-sec-butoxy mono (acetylacetonato) zirconium, tri-t-butoxy mono (acetylacetonato) zirconium, diethoxybis (acetylacetonato) zirconium, di-n-propoxybis (acetylacetate) Nato) zirconium, di-i-propoxy bis (acetylacetonato) zirconium, di-n-butoxy bis (acetylacetonato) zirconium, di-sec-butoxy bis (acetylacetonato) ziru Ni, di-t-butoxy bis (acetylacetonato) zirconium, monoethoxy tris (acetylacetonato) zirconium, mono-n-propoxytris (acetylacetonato) zirconium, mono-i-propoxytris (acetyl) Acetonato) zirconium, mono-n-butoxy-tris (acetylacetonato) zirconium, mono-sec-butoxy-tris (acetylacetonato) zirconium, mono-t-butoxy-tris (acetylacetonato) zirconium, tetrakis (acetyl) Acetonato) zirconium, triethoxy mono (ethyl acetoacetate) zirconium, tri-n-propoxy mono (ethyl acetoacetate) zirconium, tri-i-propoxy mono (ethyl acetate) Acetate) zirconium, tri-n-butoxy mono (ethyl acetoacetate) zirconium, tri-sec-butoxy mono (ethyl acetoacetate) zirconium, tri-t-butoxy mono (ethyl acetoacetate) zirconium, diethoxy bis ( Ethyl acetoacetate) zirconium, di-n-propoxy bis (ethyl acetoacetate) zirconium, di-i-propoxy bis (ethyl acetoacetate) zirconium, di-n-butoxy bis (ethyl acetoacetate) zirconium, di- sec-butoxy bis (ethyl acetoacetate) zirconium, di-t-butoxy bis (ethyl acetoacetate) zirconium, monoethoxy tris (ethyl acetoacetate) zirconium, mono-n- Propoxy tris (ethyl acetoacetate) zirconium, mono-i-propoxy tris (ethyl acetoacetate) zirconium, mono-n-butoxy tris (ethyl acetoacetate) zirconium, mono-sec-butoxy tris (ethyl acetoacetate) Zirconium, mono-t-butoxy-tris (ethylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium, mono (acetylacetonato) tris (ethylacetoacetate) zirconium, bis (acetylacetonato) bis (ethylacetoacetate) Zirconium chelate compounds such as zirconium and tris (acetylacetonate) mono (ethylacetoacetate) zirconium;
Examples thereof include aluminum chelate compounds such as tris (acetylacetonate) aluminum and tris (ethylacetoacetate) aluminum.

Examples of the organic acid include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, maleic acid, methylmalonic acid, adipic acid, sebacic acid, and gallic acid. Acid, butyric acid, meritic acid, arachidonic acid, mikimic acid, 2-ethylhexanoic acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, p-toluenesulfonic acid, benzenesulfone Examples include acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, formic acid, malonic acid, sulfonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid and the like.
Examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid.
Examples of the organic base include pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, trimethylamine, triethylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicycloocrane, diazabicyclo. Nonane, diazabicycloundecene, tetramethylammonium hydroxide and the like can be mentioned.
Examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide and the like.
These catalysts may be used alone or in combination of two or more.
Of these catalysts, metal chelate compounds, organic acids or inorganic acids are preferred, and titanium chelate compounds or organic acids are more preferred.
The amount of the catalyst used is preferably 0.001 to 10 parts by weight, more preferably 0.001 to 1 part by weight with respect to 100 parts by weight of the raw material silane compound.
Water added during the synthesis of polysiloxane can be added intermittently or continuously in the raw material silane compound or in a solution in which the silane compound is dissolved in an organic solvent.
The catalyst may be added in advance to a raw material silane compound or a solution in which the silane compound is dissolved in an organic solvent, or may be dissolved or dispersed in the added water.
The reaction temperature during the synthesis is preferably 0 to 100 ° C, more preferably 15 to 80 ° C. The reaction time is preferably 0.5 to 24 hours, more preferably 1 to 8 hours.

  The use ratio of the other polymer as described above in the liquid crystal aligning agent of the present invention is preferably 10,000 parts by weight or less, more preferably 10 to 10, based on 100 parts by weight of the polymer having a cinnamic acid skeleton. 000 parts by weight, more preferably 100 to 5,000 parts by weight, and particularly preferably 500 to 2,000 parts by weight.

The said epoxy compound can be used from a viewpoint which improves the adhesiveness with respect to the substrate surface of the liquid crystal aligning film formed. Examples of such epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexane. Diol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N′— Tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-dia Bruno diphenylmethane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl cyclohexane, may be mentioned as being preferred.
Among the above, an epoxy compound having an N, N-diglycidyl structure is preferable, and N, N, N ′, N′-tetraglycidyl-m-xylenediamine and N, N, N ′, N′-tetraglycidyl-4 are particularly preferable. It is preferable to use at least one selected from the group consisting of 4,4′-diaminodiphenylmethane.
When the liquid crystal aligning agent of the present invention contains an epoxy compound, the epoxy compound may be used in combination with an appropriate base catalyst such as 1-benzyl-2-methylimidazole for the purpose of efficiently causing an epoxy group crosslinking reaction.
The use ratio of the epoxy compound in the liquid crystal aligning agent of the present invention is preferably 100 with respect to 100 parts by weight of the total of the polymers (the total of the polymer having a cinnamic acid skeleton and the other polymers). The amount is not more than parts by weight, more preferably not more than 50 parts by weight.

The said functional silane compound can be used in order to improve the adhesiveness with the board | substrate of the liquid crystal aligning film formed. Examples of the functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl) -3. -Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltri Methoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7 Triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl- 3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene ) -3-Aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane And the patent text 17 is described in (JP 63-291922 JP) include a reaction product of a silane compound having a tetracarboxylic dianhydride and an amino group.
When the liquid crystal aligning agent of the present invention contains a functional silane compound, the content ratio is preferably 50 parts by weight or less, more preferably 20 parts by weight or less, with respect to 100 parts by weight of the total polymer. is there.

Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, silicone surfactants, polyalkylene oxide surfactants, and fluorine-containing surfactants. it can.
When the liquid crystal aligning agent of this invention contains surfactant, as the content rate, Preferably it is 10 weight part or less with respect to 100 weight part of the whole liquid crystal aligning agent, More preferably, it is 1 weight part or less. is there.

<Liquid crystal aligning agent>
As described above, the liquid crystal aligning agent of the present invention contains a polymer having a cinnamic acid skeleton as an essential component, and additionally contains other components as necessary. Preferably, each component is an organic solvent. It is prepared as a solution-like composition dissolved in
As an organic solvent that can be used for preparing the liquid crystal aligning agent of the present invention, a solvent that dissolves a polymer having a cinnamic acid skeleton and other components optionally used and does not react with these is preferable.
The organic solvent that can be preferably used in the liquid crystal aligning agent of the present invention varies depending on the type of other polymer that is optionally added.
As a preferred organic solvent in the case where the liquid crystal aligning agent of the present invention contains at least one polymer selected from the group consisting of a polymer having a cinnamic acid skeleton and a polyamic acid and polyimide, synthesis of polyamic acid The organic solvent illustrated above can be mentioned as what is used for. These organic solvents can be used alone or in combination of two or more.
On the other hand, preferred organic solvents in the case where the liquid crystal aligning agent of the present invention contains a polymer having a cinnamic acid skeleton and polysiloxane include, for example, 1-ethoxy-2-propanol, propylene glycol monoethyl ether, propylene glycol. Cole monopropyl ether, propylene glycol monobutyl ether, propylene glycol monoacetate, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol propyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene Glycol monopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol Ether monoamyl ether, ethylene glycol monohexyl ether, diethylene glycol, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate, methyl carbitol, ethyl carbitol, propyl carbitol, butyl carbitol, n-propyl acetate I-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate Benzyl acetate, n-hexyl acetate, cyclohexyl acetate, octyl acetate, amyl acetate, isoamyl acetate and the like. Of these, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate and the like can be mentioned.

The preferable solvent used for the preparation of the liquid crystal aligning agent of the present invention is obtained by combining one or more of the above organic solvents, and is contained in the liquid crystal aligning agent at the following preferable solid content concentration. Each component does not precipitate, and the surface tension of the liquid crystal aligning agent is in the range of 25 to 40 mN / m.
The solid content concentration of the liquid crystal aligning agent of the present invention, that is, the ratio of the weight of all components other than the solvent in the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent is selected in consideration of viscosity, volatility, Preferably it is the range of 1-10 weight%. The liquid crystal aligning agent of the present invention is applied to the substrate surface to form a coating film that becomes a liquid crystal aligning film. When the solid content concentration is less than 1% by weight, the film thickness of this coating film becomes too small. In some cases, it is difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, it is difficult to obtain a good liquid crystal alignment film due to excessive film thickness, and the viscosity of the liquid crystal aligning agent increases, resulting in insufficient coating characteristics. There is a case. The particularly preferable range of the solid content concentration varies depending on the method employed when the liquid crystal aligning agent is applied to the substrate. For example, when the spinner method is used, the range of 1.5 to 4.5% by weight is particularly preferable. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.
The temperature for preparing the liquid crystal aligning agent of the present invention is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 60 ° C.

<Method for forming liquid crystal alignment film>
The liquid crystal aligning agent of this invention can be used conveniently in order to form a liquid crystal aligning film by the photo-alignment method.
As a method for forming the liquid crystal alignment film, for example, a method of forming a coating film of the liquid crystal alignment film of the present invention on a substrate and then imparting liquid crystal alignment ability to the coating film by a photo-alignment method can be mentioned.
First, the liquid crystal aligning agent of the present invention is applied to the transparent conductive film side of the substrate provided with the patterned transparent conductive film by an appropriate application method such as a roll coater method, a spinner method, a printing method, an ink jet method or the like. For example, the coating film is formed by heating at a temperature of 40 to 250 ° C. for 0.1 to 120 minutes. The thickness of the coating film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm, as the thickness after removal of the solvent.
As the substrate, for example, a glass such as float glass or soda glass, a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, or polycarbonate can be used.
As the transparent conductive film, a NESA film made of SnO ₂ , an ITO film made of In ₂ O ₃ —SnO _2, or the like can be used. For patterning these transparent conductive films, a photo-etching method or a method using a mask when forming the transparent conductive film is used.
When applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate or the transparent conductive film and the coating film, a functional silane compound, titanate or the like is previously applied on the substrate and the transparent conductive film. Also good.

Next, the coating film is irradiated with linearly polarized light, partially polarized radiation or non-polarized radiation, and optionally subjected to a heat treatment at a temperature of 150 to 250 ° C., preferably for 1 to 120 minutes, thereby improving the liquid crystal alignment ability. Give. Here, as the radiation, for example, ultraviolet rays including light having a wavelength of 150 nm to 800 nm and visible light can be used, but ultraviolet rays including light having a wavelength of 300 nm to 400 nm are preferable. When the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, or from an oblique direction to give a pretilt angle, or a combination thereof. May be. When irradiating non-polarized radiation, the direction of irradiation needs to be an oblique direction.
As a light source to be used, for example, a low pressure mercury lamp, a high pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. The ultraviolet rays in the preferable wavelength region can be obtained by means of using the light source in combination with, for example, a filter, a diffraction grating, or the like.
The irradiation dose of radiation, preferably less than 1 J / ^{m 2} or more 10,000 J / ^{m 2,} more preferably from 10~3,000J / ^{m 2.} In addition, when providing the liquid crystal aligning ability by the photo-alignment method to the coating film formed from the conventionally known liquid crystal aligning agent, the irradiation dose of 10,000 J / m < ² > or more was required. However, when the liquid crystal aligning agent of the present invention is used, good liquid crystal alignment is imparted even when the radiation irradiation amount in the photo-alignment method is 3,000 J / m ² or less, and further 1,000 J / m ² or less. This contributes to the reduction of the manufacturing cost of the liquid crystal display element.
The “pretilt angle” in the present invention represents an angle of inclination of liquid crystal molecules from a direction parallel to the substrate surface.

<Method for manufacturing liquid crystal display element>
The liquid crystal display element formed using the liquid crystal aligning agent of this invention can be manufactured as follows, for example.
Prepare a pair (two sheets) of substrates on which the liquid crystal alignment film is formed as described above, and make these liquid crystal alignment films face each other so that the polarization direction of the irradiated linearly polarized radiation becomes a predetermined angle. A peripheral portion between the substrates is sealed with a sealing agent, liquid crystal is injected and filled, and a liquid crystal injection port is sealed to constitute a liquid crystal cell. Next, it is desirable that the liquid crystal cell is heated to a temperature at which the liquid crystal used takes an isotropic phase, and then cooled to room temperature to remove the flow alignment during injection.
Then, a polarizing plate is bonded to both surfaces so that the polarization direction forms a predetermined angle with the alignment easy axis of the liquid crystal alignment film of the substrate, thereby obtaining a liquid crystal display element. When the liquid crystal alignment film is horizontally aligned, by adjusting the angle formed by the polarization direction of the irradiated linearly polarized radiation and the angle between each substrate and the polarizing plate in the two substrates on which the liquid crystal alignment film is formed A liquid crystal display element having a TN type or STN type liquid crystal cell can be obtained. On the other hand, in the case where the liquid crystal alignment film is vertically aligned, the cell is configured so that the directions of easy alignment axes of the two substrates on which the liquid crystal alignment film is formed are parallel, A liquid crystal display element having a VA type liquid crystal cell can be obtained by bonding so that the polarization direction forms an angle of 45 ° with the easy alignment axis.
As the sealing agent, for example, an aluminum oxide sphere as a spacer and an epoxy resin containing a curing agent can be used.

As the liquid crystal, for example, a nematic liquid crystal, a smectic liquid crystal, or the like can be used. In the case of a TN liquid crystal cell or STN liquid crystal cell, a nematic liquid crystal having positive dielectric anisotropy is preferable. For example, biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl A cyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cubane liquid crystal, or the like is used. Further, for example, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonate, cholesteryl carbonate; chiral agents such as those sold under the trade names C-15 and CB-15 (Merck); p-decyloxybenzylidene Ferroelectric liquid crystals such as -p-amino-2-methylbutylcinnamate can be further added and used.
On the other hand, in the case of a vertical alignment type liquid crystal cell, a nematic liquid crystal having negative dielectric anisotropy is preferable. For example, dicyanobenzene liquid crystal, pyridazine liquid crystal, Schiff base liquid crystal, azoxy liquid crystal, biphenyl type. A liquid crystal, a phenylcyclohexane type liquid crystal, or the like is used.
The polarizing plate used outside the liquid crystal cell is composed of a polarizing film called “H film” in which polyvinyl alcohol is stretched and oriented while absorbing iodine and sandwiched between cellulose acetate protective films, or the H film itself. A polarizing plate etc. can be mentioned.
The liquid crystal display element of the present invention thus produced is excellent in various properties such as display characteristics and reliability.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
In the following examples, the weight average molecular weight (Mw) is a polystyrene equivalent value measured by gel permeation chromatography under the following conditions.

Column: Tosoh Co., Ltd., TSKgelGRCXLII
Solvent: Tetrahydrofuran Temperature: 40 ° C
Pressure: 68 kgf / cm ²

The epoxy equivalent was measured according to the “hydrochloric acid-methyl ethyl ketone method” of JIS C2105.
The solution viscosity is a value measured at 25 ° C. using an E-type viscometer for the polymer solution indicated in each synthesis example.
<Synthesis of a cinnamic acid derivative having a carboxyl group>
Synthesis Example 1 (Synthesis of Compound (2-1-1))
Scheme 1 below

The compound (2-1-1) was synthesized according to
A 1 L eggplant-shaped flask was charged with 82 g of p-hydroxycinnamic acid, 304 g of potassium carbonate and 400 mL of N-methyl-2-pyrrolidone, stirred at room temperature for 1 hour, and then added with 166 g of 1-bromopentane at 100 ° C. Stir for 5 hours. Thereafter, the solvent was distilled off under reduced pressure. To this, 48 g of sodium hydroxide and 400 mL of water were added and refluxed for 3 hours to conduct a hydrolysis reaction. After completion of the reaction, the reaction system was neutralized with hydrochloric acid, and the resulting precipitate was recovered and recrystallized with ethanol to obtain 80 g of white crystals of the compound represented by the above formula (2-1-1).
Synthesis Example 2 (Synthesis of Compound (2-4-1))
Scheme 2 below

Thus, compound (2-4-1) was synthesized.
Synthesis of Compound (2-4-1a) A 1 L eggplant-shaped flask was charged with 91.3 g of methyl 4-hydroxybenzoate, 182.4 g of potassium carbonate and 320 mL of N-methyl-2-pyrrolidone, and stirred at room temperature for 1 hour. After performing, 99.7 g of 1-bromopentane was added and stirred at 100 ° C. for 5 hours. After completion of the reaction, reprecipitation was performed with water. Next, 48 g of sodium hydroxide and 400 mL of water were added to the precipitate and refluxed for 3 hours to carry out a hydrolysis reaction. After completion of the reaction, the reaction mixture was neutralized with hydrochloric acid, and the resulting precipitate was recrystallized from ethanol to obtain 102 g of white crystals of the compound (2-4-1a).
Synthesis of Compound (2-4-1) 10.41 g of this compound (2-4-1a) was placed in a reaction vessel, and 100 mL of thionyl chloride and 77 μL of N, N-dimethylformamide were added thereto at 80 ° C. Stir for 1 hour. Next, thionyl chloride was distilled off under reduced pressure, methylene chloride was added, washed with an aqueous sodium hydrogen carbonate solution, dried over magnesium sulfate, concentrated, and then tetrahydrofuran was added to form a solution.
Next, in another 500 mL three-necked flask, 7.39 g of 4-hydroxycinnamic acid, 13.82 g of potassium carbonate, 0.48 g of tetrabutylammonium, 50 mL of tetrahydrofuran and 100 mL of water were charged. The aqueous solution was ice-cooled, the tetrahydrofuran solution was slowly added dropwise, and the mixture was further stirred for 2 hours. After completion of the reaction, the mixture was neutralized by adding hydrochloric acid, extracted with ethyl acetate, dried over magnesium sulfate, concentrated, and recrystallized from ethanol to give white crystals of compound (2-4-1). Of 9.0 g was obtained.
Synthesis Example 3 (Synthesis of Compound (2-4-2))
The same procedure as in Synthetic Example 2 was performed except that 110.9 g of 1-iodo-4,4,4-trifluorobutane was used instead of 1-bromopentane in Synthesis Example 2, and the following formula (2-4 -2)

9.2 g of a white powder of the compound represented by the formula:
Synthesis Example 4 (Synthesis of Compound (2-8-1))
Scheme 3 below

Thus, compound (2-8-1) was synthesized.
In the synthesis of Compound (2-4-1) of Synthesis Example 2, the compound of Synthesis Example 2 (9.91 g of 4-pentyl-transcyclohexylcarboxylic acid was used instead of Compound (2-4-1a) ( It carried out like the synthesis | combination of 2-4-1), and 13g of white crystals of the compound (2-8-1) were obtained.
Synthesis Example 5 (Synthesis of Compound (4-1-1))
Scheme 4 below

Thus, compound (4-1-1) was synthesized.
A 1 L eggplant flask equipped with a reflux tube, a nitrogen introduction tube and a Dean-Stark tube was charged with 72 g of decylsuccinic anhydride, 49 g of 4-aminocinnamic acid, 70 mL of triethylamine, 500 mL of toluene and 200 mL of tetrahydrofuran, and reacted under reflux for 36 hours. Went. After completion of the reaction, the reaction mixture was washed successively with dilute hydrochloric acid and water, dried over magnesium sulfate, concentrated, and recrystallized with a mixed solvent consisting of ethanol and tetrahydrofuran to give compound (4-1-1- 72 g of white crystals of 1) were obtained.
Synthesis Example 6 (Synthesis of Compound (4-5-1))
Scheme 5 below

The compound (4-5-1) was synthesized according to
Synthesis of Compound (4-5-1a) A 2 L eggplant flask equipped with a reflux tube was charged with 198 g of 1,2,4-cyclohexanetricarboxylic acid anhydride, 500 mL of thionyl chloride and 2 mL of N, N-dimethylformamide, and 80 ° C. The reaction was carried out under reflux for 1 hour. After completion of the reaction, thionyl chloride was removed under reduced pressure, methylene chloride was added to the residue, and the organic layer was washed successively with saturated aqueous sodium hydrogen carbonate and water, then dried over magnesium sulfate, concentrated and dried. Thereafter, 500 mL of tetrahydrofuran was added.
On the other hand, 178 g of 4,4,5,5,5-pentafluoropentanol, 160 mL of pyridine and 1.5 L of tetrahydrofuran were charged into a 3 L three-necked flask equipped with a dropping funnel, a thermometer and a nitrogen introduction tube, and cooled in an ice bath. did. A tetrahydrofuran solution containing a reaction product of the above 1,2,4-cyclohexanetricarboxylic acid anhydride and thionyl chloride was slowly added dropwise thereto, and the reaction was further performed by stirring at room temperature for 4 hours. After completion of the reaction, extraction was performed with ethyl acetate. The organic layer was washed with water and dried over magnesium sulfate, and then purified with a silica column, and the solvent was removed to dryness to obtain 268 g of compound (4-5-1a).
Synthesis of Compound (4-5-1) In a 200 mL eggplant flask equipped with a Dean-Stark tube, 241 g of Compound (4-5-1a), 109 g of 4-aminocinnamic acid, 190 mL of triethylamine, 16 g of 4-dimethylaminopyridine, toluene 1 L and 2 L of tetrahydrofuran were charged, and the reaction was performed under reflux for 24 hours. After completion of the reaction, the reaction mixture was washed successively with dilute hydrochloric acid and water. The organic layer was dried over magnesium sulfate and then recrystallized from methanol to obtain 78 g of compound (4-5-1).
Synthesis Example 7 (Compound (Synthesis of 5-1-1))
Scheme 6 below

Thus, compound (5-1-1) was synthesized.
Synthesis of Compound (5-1-1a) In a 300 mL three-necked flask equipped with a thermometer and a nitrogen introduction tube, 9.7 g of 4-nitrocinnamic acid, 12 g of 4,4,4-trifluoro-1-iodobutane, potassium carbonate 14 g and 1-methyl-2-pyrrolidone (150 mL) were charged, and the reaction was carried out by stirring at 50 ° C. for 1 hour. After completion of the reaction, the reaction mixture was extracted with ethyl acetate. The organic layer was washed with water, dried over magnesium sulfate, concentrated, and the solvent was further removed to dryness to obtain 14 g of compound (5-1-1a).
Synthesis of Compound (5-1-1b) A 300 mL three-necked flask equipped with a thermometer and a nitrogen introduction tube was charged with 14 g of Compound (5-1-1a), 53 g of tin chloride dihydrate and 150 mL of ethanol, and 70 ° C. The reaction was carried out with stirring for 1 hour. After completion of the reaction, the reaction mixture was poured into ice water, neutralized with 2M aqueous sodium hydroxide solution, and ethyl acetate was added to remove the precipitate. Ethyl acetate was added to the filtrate for extraction to obtain an organic layer. The organic layer was washed with water, dried over magnesium sulfate, concentrated, and the solvent was removed to dryness to obtain 12 g of compound (5-1-1b).
Synthesis of Compound (5-1-1) In a 200 mL eggplant flask equipped with a reflux tube and a nitrogen introduction tube, 12 g of Compound (5-1-1b), 8.7 g of 1,2,4-cyclohexanetricarboxylic acid anhydride and Acetic acid (100 mL) was added, and the reaction was performed under reflux for 1 hour. After completion of the reaction, the reaction mixture was extracted with ethyl acetate to obtain an organic layer. The organic layer was washed with water, dried over magnesium sulfate, concentrated, dried and recrystallized with a mixed solvent consisting of ethyl acetate and hexane to give white crystals of cinnamic acid derivative (5-1-1) ( 11 g of 98.3% purity was obtained.

<Synthesis of a polymer having a cinnamic acid skeleton>
Example 1
In a 200 mL three-necked flask, 2.5 g of EHPE3150 (manufactured by Daicel Chemical Industries, Ltd., weight average molecular weight = 2,200, epoxy equivalent = 177 g / mol) as a polymer having an epoxy group, as a cinnamic acid derivative having a carboxyl group 1.65 g of the compound (2-1-1) obtained in Synthesis Example 1 (corresponding to 50 mol% with respect to the amount of epoxy group calculated from the epoxy equivalent of EHPE3150), 0.25 g of tetrabutylammonium bromide and N, N-dimethylacetamide was charged and the reaction solution was reacted at 120 ° C. for 2 hours at a solid content concentration of 20% by weight. After completion of the reaction, 100 mL of ethyl acetate was added to the reaction product, washed 3 times with water, the solvent was removed and the solid was solidified to obtain a polymer (CPA-1) having a cinnamic acid skeleton. Obtained as a brown powder.
The weight average molecular weight (Mw) of the polymer (CPA-1) was 9,000.
Examples 2-8
The types and use ratios of the cinnamic acid derivatives having a carboxyl group (mol% with respect to the amount of the epoxy group calculated from the epoxy equivalent of EHPE3150) were as described in Table 1, and were the same as in Example 1 above. This was carried out to obtain polymers (CPA-2) to (CPA-7) each having a cinnamic acid skeleton. The weight average molecular weight (Mw) of each polymer is shown in Table 1.

<Synthesis of polyamic acid>
Synthesis Example 9
196 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 212 g (1, .2) of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine. 0 mol) was dissolved in 3,670 g of N-methyl-2-pyrrolidone and reacted at 40 ° C. for 3 hours to obtain about 4,000 g of a solution containing polyamic acid (PAA-1). The solution viscosity of this polyamic acid solution was 160 mPa · s.
<Synthesis of polyimide>
Synthesis Example 10
20.9 g (0.093 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 9.2 g (0.085 mol) of p-phenylenediamine as diamine and the above formula (D A compound containing polyamic acid was obtained by dissolving 4.9 g (0.009 mol) of the compound represented by -6) in 140 g of N-methyl-2-pyrrolidone and reacting at 60 ° C. for 4 hours. . A small amount of the obtained polyamic acid solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 126 mPa · s.
Next, 325 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 7.4 g of pyridine and 9.5 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration cyclization reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (by this solvent replacement operation, pyridine and acetic anhydride used in the dehydration cyclization reaction were removed from the system. The same applies hereinafter). As a result, about 190 g of a solution containing 16.1% by weight of polyimide (PI-1) having an imidation ratio of about 54% was obtained. A small amount of this polyimide solution was taken, N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 75 mPa · s.

Synthesis Example 11
2,3,5-tricarboxycyclopentylacetic acid dianhydride 17.3 g (0.077 mol) as tetracarboxylic dianhydride and 5.9 g (0.054 mol) of p-phenylenediamine as diamine, the above formula (D −6) 4.1 g (0.008 mol) of the compound represented by formula (D-7) and 7.7 g (0.016 mol) of the compound represented by the above formula (D-7) are dissolved in 140 g of N-methyl-2-pyrrolidone. And the solution containing polyamic acid was obtained by reacting at 60 degreeC for 4 hours. A small amount of the obtained polyamic acid solution was collected, and N-methyl-2-pyrrolidone was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 117 mPa · s.
Next, 325 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 6.1 g of pyridine and 7.9 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone, whereby about 210 g of a solution containing 15.4% by weight of polyimide (PI-2) having an imidation ratio of about 55% Got. A small amount of this polyimide solution was collected, and N-methyl-2-pyrrolidone was added to measure the solution viscosity as a solution having a polyimide concentration of 10% by weight. The solution viscosity was 109 mPa · s.
<Preparation of polysiloxane>
Synthesis Example 12
A 200 mL three-necked flask equipped with a condenser was charged with 20.8 g of tetraethoxysilane and 28.2 g of 1-ethoxy-2-propanol, heated to 60 ° C. and stirred. A maleic anhydride aqueous solution prepared by dissolving 0.26 g of maleic anhydride in 10.8 g of water prepared in another flask having a capacity of 20 mL was added thereto, and the reaction was performed by heating and stirring at 60 ° C. for further 4 hours. The solvent was distilled off from the resulting reaction mixture, 1-ethoxy-2-propanol was added, and the mixture was concentrated again to obtain a polymer solution containing 10% by weight of polyorganosiloxane (PS-1). The weight average molecular weight Mw of PS-1 was 5,100.

<Preparation of liquid crystal aligning agent>
Example 9
100 parts by weight of the polymer (CPA-1) having a cinnamic acid skeleton obtained in Example 1 and a polyamic acid solution containing the polyamic acid (PAA-1) obtained in Synthesis Example 9 as another polymer Combined with an amount corresponding to 1,000 parts by weight in terms of acid (PAA-1), N-methyl-2-pyrrolidone and butyl cellosolve were added thereto, and the solvent composition was N-methyl-2-pyrrolidone: butyl cellosolve = The solution was 50:50 (weight ratio) and the solid content concentration was 3.0% by weight.
Liquid crystal aligning agent A-1 was prepared by filtering this solution with a filter having a pore diameter of 1 μm.
Examples 10-20
Liquid crystal aligning agents A-2 to A-12 were carried out in the same manner as in Example 8 except that the types of polymers having a cinnamic acid skeleton and the types and amounts of other polymers were as shown in Table 2. Were prepared respectively.
Example 21
100 parts by weight of the polymer (CPA-2) having a cinnamic acid skeleton obtained in Example 2 above, and a poly of a solution containing the polysiloxane (PS-1) obtained in Synthesis Example 12 as another polymer The amount corresponding to 1,000 parts by weight in terms of siloxane (PS-1) was combined, and 1-ethoxy-2-propanol was added thereto to obtain a solution having a solid content concentration of 3.0% by weight.
Liquid crystal aligning agent A-13 was prepared by filtering this solution with a filter having a pore diameter of 1 μm.

Example 22
<Formation of liquid crystal alignment film and manufacture of VA type vertical liquid crystal display element>
On the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film, the liquid crystal aligning agent A-1 prepared in Example 9 was applied using a spinner, and the interior of the chamber was replaced with nitrogen at 1 at 200 ° C. By heating for a time, a coating film having a thickness of 0.1 μm was formed. Next, the surface of the coating film was irradiated with polarized ultraviolet rays of 1,000 J / m ² containing a 313 nm emission line from a direction inclined by 40 ° from the substrate normal line using a Hg—Xe lamp and a Grand Taylor prism. It was. The same operation was repeated to produce a pair (two) of substrates having a liquid crystal alignment film.
An epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied to the outer periphery of the surface of the substrate having the liquid crystal alignment film by screen printing, and the liquid crystal alignment film surfaces of the pair of substrates are made to face each other. The adhesive was pressure-bonded so that the projection direction of the optical axis of the ultraviolet ray of each substrate onto the substrate surface was antiparallel, and the adhesive was thermally cured at 150 ° C. for 1 hour. Next, a negative liquid crystal (MLC-6608 manufactured by Merck & Co., Inc.) was filled into the gap between the substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, this was heated at 150 ° C. and then gradually cooled to room temperature. Next, the polarizing plates are bonded to both the outer surfaces of the substrate so that the polarization directions thereof are orthogonal to each other and form an angle of 45 ° with the projection direction of the optical axis of the liquid crystal alignment film onto the substrate surface. A VA liquid crystal display element was manufactured.
This liquid crystal display element was evaluated by the following method. The evaluation results are shown in Table 3.

<Evaluation method of VA type liquid crystal display element>
(1) Evaluation of liquid crystal orientation With respect to the liquid crystal display element manufactured above, the presence or absence of abnormal domains in the change in brightness when a voltage of 5 V is turned ON / OFF (applied / released) is observed with a microscope. The case was defined as “good”.
(2) Evaluation of pretilt angle The liquid crystal display device manufactured above is subjected to the method described in Non-Patent Document 1 (T. J. Scheffer et. Al. J. Appl. Phys. Vo. 19, p2013 (1980)). In conformity, the pretilt angle was measured by a crystal rotation method using He—Ne laser light.
(3) Evaluation of voltage holding ratio After the voltage of 5 V was applied to the liquid crystal display element manufactured above with a 60 microsecond application time and a 167 millisecond span, the voltage holding ratio after 167 milliseconds from the application release was obtained. It was measured. The measuring apparatus used was VHR-1 manufactured by Toyo Corporation.
(4) Evaluation of burn-in (residual DC voltage)
A 30 Hz, 3 V rectangular wave with 5 V DC superimposed on the liquid crystal display device manufactured above is applied at an ambient temperature of 60 ° C. for 2 hours, and the voltage remaining in the liquid crystal cell immediately after the DC voltage is cut off is flicker-erased. The residual DC voltage was determined by the method.

Examples 23-32
A liquid crystal alignment film was formed in the same manner as in Example 22 except that the type of liquid crystal alignment agent used was as described in Table 3, and a VA liquid crystal display device was manufactured and evaluated. The results are shown in Table 3.
<Formation of liquid crystal alignment film and manufacture of TN alignment type liquid crystal display element>
Example 33
The liquid crystal aligning agent A-10 prepared in Example 18 was applied on the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film using a spinner, and heated at 180 ° C. for 1 hour to obtain a film thickness. A 0.1 μm coating film was formed. By using a Hg-Xe lamp and a Grand Taylor prism, the surface of this coating film was irradiated with polarized ultraviolet rays of 1,000 J / m ² containing a 313 nm emission line from a direction inclined by 40 ° from the substrate normal, thereby aligning the liquid crystal. A liquid crystal alignment film was formed by imparting performance.
The same operation as described above was repeated to produce a pair (two) of glass substrates having a liquid crystal alignment film on the transparent conductive film surface.
An epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied by screen printing to the periphery of each surface of the pair of substrates on which the liquid crystal alignment film is formed, and then the irradiation direction of polarized ultraviolet rays becomes orthogonal. The substrates were stacked and pressure-bonded as described above, and heated at 150 ° C. for 1 hour to thermally cure the adhesive. Next, a positive nematic liquid crystal (Merck, MLC-6221, containing a chiral agent) was injected and filled into the gap between the substrates through the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, this was heated at 150 ° C. for 10 minutes and then gradually cooled to room temperature. Next, a TN alignment type liquid crystal display element was manufactured by bonding the polarizing plates on both outer surfaces of the substrate so that the polarization directions thereof were orthogonal to each other and parallel to the polarization direction of the liquid crystal alignment film.
The liquid crystal orientation, voltage holding ratio, and image sticking of this liquid crystal display element were evaluated in the same manner as in Example 22. The evaluation results are shown in Table 3.
Example 34
A liquid crystal alignment film was formed in the same manner as in Example 33 except that the type of liquid crystal alignment agent used was A-11 prepared in Example 19, and a TN alignment type liquid crystal display device was manufactured and evaluated. The results are shown in Table 3.

Claims (9)

Following formula (1)

(In Formula (1), A is a single bond, a methylene group, or a C2-C6 alkylene group.)
The liquid crystal aligning agent characterized by including the reaction product of the polymer which has a repeating unit represented by these, and the cinnamic acid derivative which has a carboxyl group. A cinnamic acid derivative having a carboxyl group is represented by the following formula (2):

(In the formula (2), R ¹ is a monovalent organic group having 3 to 40 carbon atoms containing a hydrogen atom, an alkyl group or an alicyclic group having 1 to 40 carbon atoms, said alkyl group or an alicyclic group A part or all of the hydrogen atoms may be substituted with a fluorine atom, R ² is a single bond, an oxygen atom, —COO— or —OCO—, R ³ is a divalent aromatic group, divalent An alicyclic group, a divalent heterocyclic group or a divalent condensed cyclic group, R ⁴ is a single bond, an oxygen atom, —COO— or —OCO—, and R ⁵ is a fluorine atom or a cyano group A is an integer of 0 to 3, and b is an integer of 0 to 4.)
The liquid crystal aligning agent of Claim 1 which is a compound represented by these. A cinnamic acid derivative having a carboxyl group is represented by the following formula (3):

(In the formula (3), R ⁶ is a monovalent organic group having 3 to 40 carbon atoms including an alkyl group having 1 to 40 carbon atoms or an alicyclic group, and a hydrogen atom of the alkyl group or alicyclic group. May be substituted with a fluorine atom, R ⁷ is a single bond or a divalent organic group, R ⁸ is a fluorine atom or a cyano group, and c is an integer of 0 to 4. .)
The liquid crystal aligning agent of Claim 1 which is a compound represented by these. A cinnamic acid derivative having a carboxyl group is represented by the following formula (4):

(In the formula (4), R ⁹ is a monovalent organic group having 3 to 40 carbon atoms containing an alkyl group or an alicyclic group having 1 to 40 carbon atoms, hydrogen atoms of the alkyl group or an alicyclic group A part or all of may be substituted with a fluorine atom, and R ¹⁰ is a single bond, an oxygen atom, a sulfur atom or ^* —COO— (wherein a bond with “*” is bonded to R ⁹ . R ¹¹ is a hydrogen atom, or R ¹⁰ and R ¹¹ may be bonded to each other to form a ring, R ¹² is a fluorine atom or a cyano group, and d is 0-4. (It is an integer.)
The liquid crystal aligning agent of Claim 1 which is a compound represented by these. A cinnamic acid derivative having a carboxyl group is represented by the following formula (5):

(In the formula (5), R ¹³ is a divalent organic group and R ¹⁴ is a hydrogen atom or a monovalent organic group, or R ¹³ and R ¹⁴ are bonded to each other to form a ring. R ¹⁵ is a fluorine atom or a cyano group, and R ¹⁶ is an alkyl group having 1 to 20 carbon atoms that may be substituted with a fluorine atom, or 3 to 40 carbon atoms that may be substituted with a fluorine atom. (It is an alicyclic group, and e is an integer of 0 to 4.)
The liquid crystal aligning agent of Claim 1 which is a compound represented by these.   Furthermore, the liquid crystal aligning agent as described in any one of Claims 1-5 containing at least 1 sort (s) selected from the group which consists of a polyamic acid and a polyimide.   Furthermore, the liquid crystal aligning agent as described in any one of Claims 1-5 containing polysiloxane.   A method for forming a liquid crystal alignment film, comprising: applying a liquid crystal alignment agent according to any one of claims 1 to 7 on a substrate to form a coating film; and irradiating the coating film with radiation. .   A liquid crystal display element comprising a liquid crystal alignment film formed from the liquid crystal aligning agent according to claim 1.