JP2008262074A - Liquid crystal aligning agent, alignment layer, liquid crystal cell and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new liquid crystal aligning agent which exhibits liquid crystal alignment control ability according to the photoirradiated amount. <P>SOLUTION: The liquid crystal aligning agent comprises a polymer having a repeating unit represented by formula (I), wherein R<SP>1</SP>-R<SP>3</SP>each represents a hydrogen atom or a substituent; Y<SP>1</SP>represents a predetermined linking group; Ar<SP>1</SP>represents a 1-10C substituted or unsubstituted aromatic ring group; R<SP>4</SP>and R<SP>5</SP>, each independently represent a substituent; m represents an integer of 2-5, n represents an integer of 1-3; and p represents an integer of 0-4, and q represents an integer of 0-5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal aligning agent useful for controlling the alignment of a liquid crystal material, and an alignment film. The present invention also relates to a liquid crystal cell and a liquid crystal display device using the alignment film.

An alignment film that can be manufactured by light irradiation has been proposed as an alignment film for controlling the alignment of a liquid crystal material.
For example, Patent Document 1 discloses a method for producing an alignment film by irradiating a photoreactive polymer material with natural light. However, the alignment film manufactured in this way has a problem that the alignment is not fixed and the stability, particularly the thermal stability is low.
Patent Document 2 proposes a photoalignment material in which a predetermined side chain structure is introduced into a maleimide (co) polymer. However, since such a photo-alignment material has a high glass transition temperature, a large amount of light irradiation is necessary for the alignment.
JP 2000-212310 A Japanese Patent No. 3612308

The subject of this invention is providing the novel liquid crystal aligning agent which produces a liquid crystal aligning function by light irradiation, and the alignment film which consists of this liquid crystal aligning agent.
Moreover, the other subject of this invention is providing the liquid crystal aligning agent which expressed the liquid crystal orientation control ability by the small light irradiation amount by which the said subject was solved.
Another object of the present invention is to provide a liquid crystal aligning agent capable of forming an alignment film that exhibits liquid crystal alignment control ability and has good stability to heat with a small amount of light irradiation. .
Another object of the present invention is to provide a novel alignment film formed by light irradiation, and a liquid crystal cell and a liquid crystal display device using the alignment film.

式中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立して、水素原子又は置換基を表し；
Ｙ¹は下記の連結基群
（連結基群）
−Ｏ−、−ＣＯ−、−ＮＲ⁶−（Ｒ⁶は、水素原子又はアルキル基を表す）、−Ｓ−、アルキレン基、及びアリーレン基
から選ばれる２価の連結基又は下記の連結基群から選ばれる２つ以上を組み合わせて形成される２価の連結基を表し；
Ａｒ¹は、炭素数１〜１０の置換もしくは無置換の芳香環の基を表し；
Ｒ⁴及びＲ⁵はそれぞれ独立して、置換基を表し；
ｎは１〜３の整数を表し、ｐは０〜４の整数を表し、及びｑは０〜５の整数を表す。
［２］ ｑが１以上の整数であり、ｑ個のＲ⁵のうち少なくとも一つが重合性基を含む置換基であることを特徴とする［１］の液晶配向剤。 [1] A liquid crystal aligning agent comprising a polymer having a repeating unit represented by the following formula (I):

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent;
Y ¹ is the following linking group group (linking group group)
-O -, - CO -, - NR 6 - (R 6 represents a hydrogen atom or an alkyl group), - S-, an alkylene group, and a divalent linking group or a linking group group of the following selected from the arylene group Represents a divalent linking group formed by combining two or more selected from:
Ar ¹ represents a substituted or unsubstituted aromatic ring group having 1 to 10 carbon atoms;
R ⁴ and R ⁵ each independently represents a substituent;
n represents an integer of 1 to 3, p represents an integer of 0 to 4, and q represents an integer of 0 to 5.
[2] The liquid crystal aligning agent according to [1], wherein q is an integer of 1 or more, and at least one of q R ⁵ is a substituent containing a polymerizable group.

式中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立して、水素原子又は置換基を表し；
Ｙ¹は下記の連結基群
（連結基群）
−Ｏ−、−ＣＯ−、−ＮＲ⁶−（Ｒ⁶は、水素原子又はアルキル基を表す）、−Ｓ−、アルキレン基、及びアリーレン基
から選ばれる２価の連結基又は下記の連結基群から選ばれる２つ以上を組み合わせて形成される２価の連結基を表し、
Ａｒ¹及びＡｒ²は、それぞれ独立して、炭素数１〜１０の置換もしくは無置換の芳香環の基を表し；
ｎは１〜３の整数を表す。 [3] A liquid crystal aligning agent which is a polymer having at least a repeating unit represented by the following formula (II) and having at least one polymerizable group:

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent;
Y ¹ is the following linking group group (linking group group)
-O -, - CO -, - NR 6 - (R 6 represents a hydrogen atom or an alkyl group), - S-, an alkylene group, and a divalent linking group or a linking group group of the following selected from the arylene group Represents a divalent linking group formed by combining two or more selected from:
Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic ring group having 1 to 10 carbon atoms;
n represents an integer of 1 to 3.

[4] The liquid crystal aligning agent according to any one of [1] to [3], further comprising at least one repeating unit derived from a (meth) acrylic acid monomer.
[5] The liquid crystal aligning agent according to [4], wherein the repeating unit derived from the (meth) acrylic acid monomer has at least one polymerizable group.
[6] An alignment film containing the liquid crystal aligning agent according to any one of [1] to [5].
[7] A liquid crystal cell having a pair of substrates arranged opposite to each other and a liquid crystal layer between the pair of substrates, and having the alignment film of [6] on at least one opposing surface of the pair of substrates. Characteristic liquid crystal cell.
[8] A liquid crystal display device having the liquid crystal cell of [7].

ADVANTAGE OF THE INVENTION According to this invention, the novel liquid crystal aligning agent which produces a liquid crystal aligning function by light irradiation, and the alignment film which consists of this liquid crystal aligning agent can be provided.
Moreover, according to the 1st aspect of this invention, the liquid crystal aligning agent which expresses liquid crystal alignment control ability can be provided with little light irradiation amount.
In addition, according to the second aspect of the present invention, there is provided a liquid crystal aligning agent capable of forming an alignment film that exhibits liquid crystal alignment control ability and has good stability to heat with a small amount of light irradiation. be able to.
Further, according to the present invention, it is possible to provide a novel alignment film formed by light irradiation, a liquid crystal cell and a liquid crystal display device using the alignment film.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
In the present specification, the polymer includes not only a polymer composed of one type of monomer but also a so-called copolymer composed of two or more types of monomers.
In the present invention, a “group” such as an alkyl group may have a substituent or may not have a substituent unless otherwise specified. Thus, for example, in the case of “an alkyl group having a carbon number of A to B”, the alkyl group may or may not have a substituent, and when it has a substituent, The carbon number of the substituent is also interpreted as being included in the carbon numbers A and B.

[Liquid crystal aligning agent]
The 1st aspect of the liquid crystal aligning agent of this invention consists of a polymer which has a repeating unit represented by the following general formula (I), It is characterized by the above-mentioned. The repeating unit represented by the following general formula (I) has a photoreactive group. The chemical structure of the photoreactive group is changed by light irradiation from a single direction, whereby the anisotropy of the molecule is changed in an arbitrary direction, and a liquid crystal alignment function is generated. Accordingly, when the liquid crystal is disposed on the surface irradiated with the liquid crystal aligning agent of the first aspect, the liquid crystal can be stably aligned by the liquid crystal alignment function generated due to the photoreactive group.
The liquid crystal aligning agent of the first aspect of the present invention is preferably a polymer having a polymerizable group. When it has a polymerizable group, an alignment film having high thermal stability can be formed by crosslinking the polymerizable group after imparting a liquid crystal alignment function by light irradiation.

  A second aspect of the liquid crystal aligning agent of the present invention is a polymer having at least a repeating unit represented by the following formula (II) and having at least one polymerizable group. The repeating unit represented by the following general formula (II) has a photoreactive group. The chemical structure of the photoreactive group is changed by light irradiation from a single direction, whereby the anisotropy of the molecule is changed in an arbitrary direction, and a liquid crystal alignment function is generated. Therefore, when the liquid crystal is disposed on the surface irradiated with the liquid crystal aligning agent of the second aspect, the liquid crystal can be stably aligned by the liquid crystal alignment function generated due to the photoreactive group. And since the liquid crystal aligning agent of the 2nd aspect has a polymeric group, after providing a liquid crystal aligning function by light irradiation, it hardens | cures by making reaction of this polymeric group advance, and alignment with high thermal stability. A film can be formed.

  Each of the liquid crystal aligning agents of the first and second aspects may be a polymer having another repeating unit. Of course, the polymerizable group may have other repeating units. The other repeating unit is preferably a repeating unit derived from a monomer selected from (meth) acrylic monomers.

Hereinafter, the liquid crystal aligning agent of each aspect will be described.
The liquid crystal aligning agent of the 1st aspect of this invention is a polymer which has at least the repeating unit represented by the following general formula (I).

式中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立して、水素原子又は置換基を表し；
Ｙ¹は下記の連結基群
（連結基群）
−Ｏ−、−ＣＯ−、−ＮＲ⁶−（Ｒ⁶は、水素原子又はアルキル基を表す）、−Ｓ−、アルキレン基、及びアリーレン基
から選ばれる２価の連結基又は下記の連結基群から選ばれる２つ以上を組み合わせて形成される２価の連結基を表し；
Ａｒ¹は、炭素数１〜１０の置換もしくは無置換の芳香環の基を表し；
Ｒ⁴及びＲ⁵はそれぞれ独立して、置換基を表し；
ｎは１〜３の整数を表し、ｐは０〜４の整数を表し、及びｑは０〜５の整数を表す。

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent;
Y ¹ is the following linking group group (linking group group)
-O -, - CO -, - NR 6 - (R 6 represents a hydrogen atom or an alkyl group), - S-, an alkylene group, and a divalent linking group or a linking group group of the following selected from the arylene group Represents a divalent linking group formed by combining two or more selected from:
Ar ¹ represents a substituted or unsubstituted aromatic ring group having 1 to 10 carbon atoms;
R ⁴ and R ⁵ each independently represents a substituent;
n represents an integer of 1 to 3, p represents an integer of 0 to 4, and q represents an integer of 0 to 5.

  The liquid crystal aligning agent of the second aspect of the present invention is a polymer having at least a repeating unit represented by the following general formula (II) and having at least one polymerizable group.

式中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立して、水素原子又は置換基を表し；
Ｙ¹は下記の連結基群
（連結基群）
−Ｏ−、−ＣＯ−、−ＮＲ⁶−（Ｒ⁶は、水素原子又はアルキル基を表す）、−Ｓ−、アルキレン基、及びアリーレン基
から選ばれる２価の連結基又は下記の連結基群から選ばれる２つ以上を組み合わせて形成される２価の連結基を表し、
Ａｒ¹及びＡｒ²は、それぞれ独立して、炭素数１〜１０の置換もしくは無置換の芳香環の基を表し；
ｎは１〜３の整数を表す。

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent;
Y ¹ is the following linking group group (linking group group)
-O -, - CO -, - NR 6 - (R 6 represents a hydrogen atom or an alkyl group), - S-, an alkylene group, and a divalent linking group or a linking group group of the following selected from the arylene group Represents a divalent linking group formed by combining two or more selected from:
Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic ring group having 1 to 10 carbon atoms;
n represents an integer of 1 to 3.

In the above (I) and (II), when R ¹ , R ² and R ³ each represent a substituent, the substituent is preferably an alkyl group or a halogen atom. R ¹ , R ^2, and R ³ are each preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a chlorine atom, more preferably a hydrogen atom, a methyl group, an ethyl group, or a chlorine atom, a hydrogen atom, or a methyl atom More preferred are groups. R ² and R ³ are particularly preferably a hydrogen atom.

In the formulas (I) and (II), Y ¹ preferably contains —O—, —CO—, —NR ⁶ —, an alkylene group, or an arylene group, and —CO—, —O—, — More preferably, it contains NR ^6- and an alkylene group, and further more preferably contains -CO-, -O- and an alkylene group. If Y ¹ comprises an alkylene group, the carbon number of the alkylene group is preferably 1 to 10, more preferably 1 to 8, even more preferably 1-6. Specific examples of particularly preferred alkylene groups include methylene, ethylene, trimethylene, tetrabutylene, hexamethylene groups and the like. Y ¹ is or contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, particularly preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene and naphthalene groups. When Y ¹ includes a divalent linking group (that is, an aralkylene group) obtained by combining an alkylene group and an arylene group, the carbon number of the aralkylene group is preferably 7 to 34, more preferably 7 to 26, and particularly preferably. Is 7-16. Specific examples of particularly preferred aralkylene groups include a phenylenemethylene group, a phenyleneethylene group, and a methylenephenylene group. The group mentioned as Y ¹ may have an appropriate substituent.

In the formulas (I) and (II), Ar ¹ is preferably a benzene ring, thiophene ring, furan ring, or naphthalene ring group, and more preferably a benzene ring group.
When Ar ¹ has a substituent, examples of the substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, and an alkylcarbonyl having 1 to 6 carbon atoms. Group, C1-C6 alkylcarbonyloxy group, C1-C6 alkylcarbonylthio group, C1-C6 alkylcarbonylamino group, halogen atom, cyano group, nitro group, cyano group, etc. More preferred substituents include methyl group, ethyl group, methoxy group, fluorine atom, chlorine atom, bromine atom and cyano group.
These substituents may be substituted with other substituents, and preferred substituents in this case are also as defined above. Moreover, when it has two or more substituents, each substituent may be the same or different. If possible, the substituents may be bonded to each other to form a ring.

  In the general formulas (I) and (II), n represents an integer of 1 to 3, and is preferably 1 or 2.

In the general formula (II), Ar ² is preferably a benzene ring, furan ring or naphthalene ring group, and more preferably a benzene ring group. When Ar ² has a substituent, examples of the substituent include alkyl group, alkenyl group, alkynyl group, alkoxyl group, alkylthio group, alkylcarbonyl group, alkylcarbonyloxy group, alkylcarbonylthio group, alkylcarbonylamino group, alkyloxy group Examples include carbonyloxy group, alkyloxycarbonylthio group, alkyloxycarbonylamino group, alkylthiocarbonyloxy group, alkylaminocarbonylamino group, alkylaminocarbonyloxy group, halogen atom, cyano group, nitro group, and aryl group. More preferred substituents are alkyl groups having 1 to 20 carbon atoms, alkoxyl groups having 1 to 20 carbon atoms, alkylthio groups having 1 to 20 carbon atoms, alkylcarbonyl groups having 1 to 20 carbon atoms, and 1 to 20 carbon atoms. Alkyl Rubonyloxy group, alkylcarbonylamino group having 1 to 20 carbon atoms, alkyloxycarbonyloxy group having 1 to 20 carbon atoms, alkyloxycarbonylthio group having 1 to 20 carbon atoms, alkyloxycarbonylamino group having 1 to 20 carbon atoms And an alkylaminocarbonyloxy group having 1 to 20 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, a cyano group, a nitro group, and an aryl group having 6 to 30 carbon atoms. The substituent is preferably a polymerizable group described later or a substituent containing a polymerizable group described later.
These substituents may be substituted with other substituents, and preferred substituents in this case are also as defined above. Moreover, when it has two or more substituents, each substituent may be the same or different. If possible, the substituents may be bonded to each other to form a ring.

In the general formula (I), when p is 1 or more, the substituent represented by R ⁴ is the same as the example of the substituent that Ar ² has. When a plurality of R ⁴ are present, they may be the same or different.
In the general formula (I), when q is 1 or more, the substituent represented by R ⁵ is the same as the example of the substituent that Ar ² has. When a plurality of R ⁵ are present, they may be the same as or different from each other. In addition, when R ⁵ is a p-position substituent, a phenylene group selected from the following substituent group is a linearly bonded substituent, or an alkoxy group having a polymerizable group described below at the end. Is preferred. Alternatively, the p-position is preferably unsubstituted without any substituent.

式中、Ｒは置換基でありそれぞれ同一であっても異なっていてもよく、その具体例は、Ａｒ²が有する置換基の例と同様である。ｒは０〜５、ｔは０〜４の整数である。Ｒが末端のベンゼン環のｐ位の置換基である場合は、後述する重合性基を末端に有するアルコキシ基であるのが好ましい。あるいは、末端のベンゼン環のｐ位には、置換基が存在しない、無置換であるのも好ましい。

In the formula, R is a substituent, which may be the same or different, and specific examples thereof are the same as the examples of the substituent that Ar ² has. r is an integer of 0 to 5, and t is an integer of 0 to 4. When R is a substituent at the p-position of the terminal benzene ring, it is preferably an alkoxy group having a polymerizable group described later at the terminal. Alternatively, it is also preferred that there is no substituent at the p-position of the terminal benzene ring, which is unsubstituted.

  The liquid crystal aligning agent of the first aspect of the present invention preferably has a polymerizable group, and the liquid crystal aligning agent of the second aspect of the present invention has at least one polymerizable group. The polymerizable group is not particularly limited, but is preferably a polymerizable group capable of addition polymerization reaction or condensation polymerization reaction. Examples of polymerizable groups are shown below.

  As the polymerizable group, a polymerizable group that undergoes radical polymerization or cationic polymerization is preferable. As the radical polymerizable group, a generally known radical polymerizable group can be used, and a (meth) acrylate group can be mentioned as a preferable one. As the cationic polymerizable group, generally known cationic polymerizable groups can be used. Specifically, alicyclic ether group, cyclic acetal group, cyclic lactone group, cyclic thioether group, spiro orthoester group, vinyloxy group Examples include groups. Of these, alicyclic ether groups and vinyloxy groups are preferred, and epoxy groups, oxetanyl groups, and vinyloxy groups are particularly preferred.

  As described above, the polymer having a repeating unit represented by the general formula (I) or (II) may contain one type of repeating unit represented by the general formula (I) or (II). Two or more kinds may be included. Moreover, the polymer which has a repeating unit represented by the said general formula (I) or (II) may have 1 type (s) or 2 or more types of repeating units other than said each repeating unit, respectively. The other repeating units are not particularly limited, and preferred examples thereof include repeating units derived from ordinary radical polymerizable monomers. Hereinafter, specific examples of monomers for deriving other repeating units will be given.

Monomer group (1) Alkenes ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-dodecene, 1-octadecene, 1-eicosene, hexafluoropropene, vinylidene fluoride, chlorotrifluoroethylene, 3, 3, 3-trifluoropropylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride, etc .;
(2) Dienes 1,3-butadiene, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2-n-propyl-1,3-butadiene, 2,3-dimethyl-1,3 -Butadiene, 2-methyl-1,3-pentadiene, 1-phenyl-1,3-butadiene, 1-α-naphthyl-1,3-butadiene, 1-β-naphthyl-1,3-butadiene, 2-chloro -1,3-butadiene, 1-bromo-1,3-butadiene, 1-chlorobutadiene, 2-fluoro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 1,1,2- Trichloro-1,3-butadiene and 2-cyano-1,3-butadiene, 1,4-divinylcyclohexane and the like;

(3) Derivatives of α, β-unsaturated carboxylic acid (3a) Alkyl acrylates Methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate , Amyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, tert-octyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 2-bromoethyl acrylate, 4-chlorobutyl acrylate, 2-cyanoethyl acrylate, 2-acetoxyethyl acrylate, methoxybenzyl Chryrate, 2-chlorocyclohexyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, 2-methoxyethyl acrylate, ω-methoxypolyethylene glycol acrylate (number of added polyoxyethylene: n = 2 to 100), 3-methoxy Butyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2- (2-butoxyethoxy) ethyl acrylate, 1-bromo-2-methoxyethyl acrylate, 1,1-dichloro-2-ethoxyethyl acrylate, glycidyl acrylate Such);

(3b) Alkyl methacrylates Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2 -Ethylhexyl methacrylate, n-octyl methacrylate, stearyl methacrylate, benzyl methacrylate, phenyl methacrylate, allyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, cresyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, ω Methoxypolyethylene glycol methacrylate (number of added polyoxyethylene: n = 2 to 100), 2-acetoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2- (2-butoxyethoxy) ethyl methacrylate Glycidyl methacrylate, 3-trimethoxysilylpropyl methacrylate, allyl methacrylate, 2-isocyanatoethyl methacrylate, etc .;

(3c) Diesters of unsaturated polycarboxylic acids Dimethyl maleate, dibutyl maleate, dimethyl itaconate, dibutyl taconate, dibutyl crotonate, dihexyl crotonate, diethyl fumarate, dimethyl fumarate, etc .;

(3d) Amides of α, β-unsaturated carboxylic acids N, N-dimethylacrylamide, N, N-diethylacrylamide, Nn-propylacrylamide, N-tertbutylacrylamide, N-tertoctylmethacrylamide, N- Cyclohexylacrylamide, N-phenylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, N-benzylacrylamide, N-acryloylmorpholine, diacetone acrylamide, N-methylmaleimide and the like;

(4) Unsaturated nitriles Acrylonitrile, methacrylonitrile, etc .;
(5) Styrene and its derivatives Styrene, vinyl toluene, ethyl styrene, p-tert butyl styrene, methyl p-vinyl benzoate, α-methyl styrene, p-chloromethyl styrene, vinyl naphthalene, p-methoxy styrene, p-hydroxy Methyl styrene, p-acetoxy styrene, etc .;
(6) Vinyl esters Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, vinyl methoxyacetate, vinyl vinyl acetate, etc .;

(7) Vinyl ethers Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, n-dodecyl Vinyl ether, n-eicosyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, fluorobutyl vinyl ether, fluorobutoxyethyl vinyl ether, etc .; and (8) other polymerizable monomers N-vinyl pyrrolidone, methyl vinyl ketone, phenyl vinyl ketone, Methoxyethyl vinyl ketone, 2-vinyl oxazoline, 2-isopropenyl oxazoline, etc.

  Preferred examples of the liquid crystal aligning agent of the first aspect of the present invention include a polymer having a repeating unit represented by the general formula (I) and a repeating unit represented by the following general formula (III). Preferred examples of the liquid crystal aligning agent of the second aspect of the present invention include a polymer having a repeating unit represented by the general formula (II) and a repeating unit represented by the following general formula (III). It is done.

In the formula (III), R ¹ , R ² and R ³ have the same meanings as those in the general formulas (I) and (II), and preferred ranges are also the same.

In formula (III), S ¹ represents a divalent linking group.
S ¹ is preferably an alkylene group, an alkenylene group, an arylene group, a divalent heterocyclic residue, —CO—, —NR ⁵ — (R ⁵ is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom), A divalent linking group selected from the group consisting of —O—, —S—, —SO—, —SO ₂ — and combinations thereof is preferable. The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The arylene group preferably has 6 to 10 carbon atoms. The alkylene group, alkenylene group and arylene group may be substituted with a substituent (such as an alkyl group, a halogen atom, a cyano group, an alkoxy group, or an acyloxy group) if possible, but is preferably unsubstituted. .
S ¹ preferably contains —O—, —CO—, —NR ⁵ — (R ⁵ is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom), an alkylene group or an arylene group, It is particularly preferred that it contains-, -CO-, an alkylene group or an arylene group. Further, S ¹ is preferably composed only of —O—, —CO—, an alkylene group, or an arylene group.

In the formula (III), M represents a mesogenic group. Examples of the mesogenic group represented by M include Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), and the like.
Preferably, it is a mesogen group represented by the following general formula (IV).

In General Formula (IV), L ¹ and L ² each represent a single bond or a divalent linking group, Cy ¹ , Cy ² and Cy ³ each represent a divalent cyclic group, and p is 0 to 0 Represents an integer of 2. When p is 2, two L ² may be the same or different, and two Cy ² may be the same or different.

In the general formula (IV), L ¹ or L ² is preferably —O—, —S—, —CO—, —NR ⁷ —, a divalent chain group, a divalent cyclic group and the like, respectively. It is a bivalent coupling group selected from the group which consists of these, or a single bond. R ⁷ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and more preferably a methyl group, an ethyl group or a hydrogen atom. The hydrogen atom is most preferred.
The divalent chain group is preferably an alkylene group, an alkenylene group or an alkynylene group, and these may have a substituent. As the substituent, a halogen atom is preferable. An alkylene group or an alkenylene group is preferable, and an unsubstituted alkylene group or an unsubstituted alkenylene group is more preferable. The alkylene group may have a branch. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 8 carbon atoms. The alkenylene group may have a branch. The alkenylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 8 carbon atoms.

The alkynylene group may have a branch. The alkynylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 8 carbon atoms.
Specific examples of the divalent chain group include ethylene group, trimethylene group, propylene group, tetramethylene group, 2-methyl-tetramethylene group, pentamethylene group, hexamethylene group, octamethylene group, 2-butenylene group, 2-butynylene group etc. are mentioned.
Divalent cyclic group has the same meaning as Cy ^1, Cy ² and Cy ³ to be described later, a preferred range is also the same.

  In the general formula (IV), p is preferably 0 or 1.

In the general formula (IV), Cy ¹ , Cy ² and Cy ³ are each independently a divalent cyclic group. The ring contained in the cyclic group is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring, and even more preferably a 6-membered ring. The ring contained in the cyclic group may be a single ring or a condensed ring, and is preferably a single ring. The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the aliphatic ring include a cyclohexane ring. Examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring. As the cyclic group having a benzene ring, a 1,4-phenylene group is preferable. As the cyclic group having a naphthalene ring, a naphthalene-1,5-diyl group and a naphthalene-2,6-diyl group are preferable. The cyclic group having a cyclohexane ring is preferably a 1,4-cyclohexylene group. The cyclic group having a pyridine ring is preferably a pyridine-2,5-diyl group. The cyclic group having a pyrimidine ring is preferably a pyrimidine-2,5-diyl group.
The cyclic group may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted with a halogen atom, an alkoxy group having 1 to 5 carbon atoms, carbon An alkylthio group having 1 to 5 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, a carbamoyl group, a carbamoyl group substituted with an alkyl group having 2 to 6 carbon atoms, and 2 to 2 carbon atoms 6 acylamino groups are included.

  In the first aspect, one of the repeating units of the formulas (I) and (III) may have a polymerizable group, and preferably one of them has a polymerizable group. In the second aspect, at least one of the repeating units of the formulas (II) and (III) has a polymerizable group, and preferably the repeating unit of the formula (III) has a polymerizable group.

  Preferred examples of the liquid crystal aligning agent of the first aspect include a polymer having a repeating unit represented by the general formula (I) and a repeating unit represented by the following general formula (V), Preferable examples of the liquid crystal aligning agent of the second aspect include a polymer having a repeating unit represented by the general formula (II) and a repeating unit represented by the following general formula (V).

In the formula, R ¹ , R ² and R ³ each represent a hydrogen atom or a substituent, S ¹ and S ² each independently represent a divalent linking group, M represents a mesogenic group, and P ¹ represents A polymerizable group is shown.
R ¹ , R ² and R ³ have the same meanings as those in the general formula (I), and preferred ranges thereof are also the same.
S ¹ and S ² are respectively synonymous with S ¹ in the general formula (III), and their preferred ranges are also the same.
The mesogenic group represented by M is synonymous with M in the general formula (III), and its preferred range is also the same.
Examples of the polymerizable group represented by P ¹ are as described above, and preferred ranges thereof are also the same.

  Since the repeating unit of the general formula (V) has a polymerizable group, the repeating unit of the formula (I) or the formula (II) to be combined may or may not have a polymerizable group. Is preferred.

  Another preferred example of the liquid crystal aligning agent of the first aspect includes a polymer having a repeating unit represented by the general formula (I) and a repeating unit represented by the following general formula (VI). .

In the formula, each of R ¹ , R ² and R ³ represents a hydrogen atom or a substituent, S ¹ represents a divalent linking group, and Alk represents a linear or branched alkylene group having 1 to 8 carbon atoms. N represents an integer of 1-20.
R ¹ , R ² and R ³ have the same meanings as those in the general formula (I), and preferred ranges thereof are also the same.
S ¹ has the same meaning as S ¹ in the general formula (III), and its preferred range is also the same.
Alk is preferably an alkylene group having 2 to 6 carbon atoms, such as ethylene or iso-propylene.
n is preferably an integer of 1 to 8.

  One of the repeating units of the formulas (I) and (VI) may have a polymerizable group, examples of the polymerizable group are as described above, and preferred ranges are also the same.

  Although the specific example of the liquid crystal aligning agent of the 1st and 2nd aspect of this invention is given to the following, it is not restrict | limited to the following specific examples. In addition, x, y, z in a formula shows the mole percentage of each repeating unit.

  In the polymer which is a liquid crystal aligning agent of the present invention, the repeating unit represented by the general formula (I) or (II) is preferably 5 mol% or more, and more preferably 10 mol% or more. .

The polymer preferably has a weight average molecular weight (Mw) of 1,000 to 1,000,000, more preferably 5,000 to 200,000, and still more preferably 10,000 to 100,000. The weight average molecular weight can be measured as a value in terms of polystyrene (PS) using gel permeation chromatography (GPC).
The degree of polymerization is not particularly limited, but is generally 20 or more.
The glass transition temperature (Tg) of the polymer is preferably room temperature to 50 ° C.

  The polymer which is the liquid crystal aligning agent of the present invention can be produced, for example, by advancing a polymerization reaction of monomers corresponding to each repeating unit. These monomers can be synthesized by a known method. Various commercially available monomers can also be used. As the polymerization method, radical polymerization is preferred. As the polymerization initiator used for radical polymerization, various radical polymerization initiators such as radical thermal polymerization initiators and radical photopolymerization initiators can be used, and it is particularly preferable to use radical thermal polymerization initiators. . Here, the radical thermal polymerization initiator is a compound that generates radicals by heating to a decomposition temperature or higher. Examples of such radical thermal polymerization initiators include diacyl peroxide (acetyl peroxide, benzoyl peroxide, etc.), ketone peroxide (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), hydroperoxide (hydrogen peroxide, tert. -Butyl hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyesters (tert-butyl peroxyacetate, tert) -Butyl peroxypivalate), azo compounds (azobisisobutyronitrile, azobisisovaleronitrile, etc.), persulfates (ammonium persulfate, Sodium sulfate, potassium sulfate) and the like. Such radical thermal polymerization initiators can be used alone or in combination of two or more.

The radical polymerization can proceed in various forms such as an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, and a solution polymerization method. Solution polymerization, which is a typical radical polymerization method, will be described more specifically. The outlines of other polymerization methods are the same, and details thereof are described in, for example, “Polymer Chemistry Experimental Methods” edited by Polymer Society (Tokyo Kagaku Dojin, 1981).
In solution polymerization, an organic solvent is used. The organic solvent is usually an organic compound having a boiling point in the range of 50 to 200 ° C. under atmospheric pressure, and the organic solvent used for solution polymerization is an organic solvent that uniformly dissolves raw materials such as monomers. Is desirable. Examples of preferable organic solvents include alcohols such as isopropanol and butanol, ethers such as dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofuran and dioxane, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethyl acetate and acetic acid. Examples thereof include esters such as butyl, amyl acetate and γ-butyrolactone, amides such as dimethylamide and dimethylformamide, and aromatic hydrocarbons such as benzene, toluene and xylene. In addition, these organic solvents can be used individually by 1 type or in combination of 2 or more types. Furthermore, a water-mixed organic solvent in which water is used in combination with the above organic solvent is also applicable from the viewpoint of the solubility of the monomer and the polymer to be produced.

  Also, the conditions for solution polymerization are not particularly limited, and examples include polymerization conditions for 10 minutes to 30 hours within a temperature range of 50 to 200 ° C. Furthermore, it is desirable that the inert gas atmosphere be used not only during solution polymerization but also before the start of solution polymerization so that generated radicals are not deactivated. As the inert gas, nitrogen gas or the like is preferably used.

  In order to make the obtained polymer into a preferable molecular weight range, a chain transfer agent may be used. Examples of the chain transfer agent include mercaptans (for example, octyl mercaptan, decyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, octadecyl mercaptan, thiophenol, p-nonylthiophenol), polyhalogenated alkyl (for example, carbon tetrachloride). , Chloroform, 1,1,1-trichloroethane, 1,1,1-tribromooctane, etc.) and low-activity monomers (α-methylstyrene, α-methylstyrene dimer, etc.) can be used, but preferably Is a mercaptan having 4 to 16 carbon atoms. The amount of these chain transfer agents used can be determined according to the activity of the chain transfer agent, the combination of monomers, the polymerization conditions, and the like. Preferably, they are 0.01 mol%-50 mol% with respect to the total number of moles of the monomer to be used, More preferably, it is 0.05 mol%-30 mol%, More preferably, it is 0.08 mol%-25 mol%. These chain transfer agents may be present in the system simultaneously with the target monomer whose degree of polymerization is to be controlled in the polymerization process, and the addition method is not particularly limited. It may be added after being dissolved in the monomer, or may be added separately from the monomer.

The liquid crystal aligning agent of the present invention is useful as a material for forming an alignment film. Hereinafter, the alignment film of the present invention formed using the liquid crystal aligning agent of the present invention will be described.
[Alignment film]
The alignment film of the present invention contains the liquid crystal aligning agent of the present invention. When the polymer as the liquid crystal aligning agent has a polymerizable group, as described later, when forming the alignment film, the polymerizable group may be polymerized and fixed. “Containing liquid crystal aligning agent” means not only an embodiment containing the same as it is, but in the case of a liquid crystal aligning agent having a polymerizable group, the polymerizable group reacts and binds within or between molecules. The aspect contained in a state shall also be included.

The alignment film may be formed from a composition containing various additives as necessary together with the liquid crystal alignment agent. Examples of the additive include a polymerization initiator, a plasticizer, and a surfactant. The polymerization initiator mainly contributes to improving the strength of the film, and the surfactant and the plasticizer mainly contribute to improving the surface uniformity and orientation of the alignment film.
30 mass% or less is preferable with respect to the said liquid crystal aligning agent, and, as for the total amount of these addition amounts, 10 mass% or less is more preferable.

The polymerization initiator is preferably a photopolymerization initiator or a photopolymerization initiator system. Examples thereof include vicinal polyketaldonyl compounds disclosed in US Pat. No. 2,367,660 and US Pat. No. 2,448,828. The acyloin ether compounds described in the specification, aromatic acyloin compounds substituted with α-hydrocarbons described in US Pat. No. 2,722,512, US Pat. Nos. 3,046,127 and 2,951,758 A polynuclear quinone compound described in US Pat. No. 3,549,367, a combination of a triarylimidazole dimer and a p-aminoketone, and a benzothiazole compound and a trihalomethyl-s-triazine compound described in Japanese Patent Publication No. 51-48516 A bird cage described in US Pat. No. 4,239,850 Methyl - triazine compound include a trihalomethyl oxadiazole compounds described in U.S. Pat. No. 4,212,976. In particular, trihalomethyl-s-triazine, trihalomethyloxadiazole, and triarylimidazole dimer are preferable. In addition, “polymerization initiator C” described in JP-A-11-133600 can also be mentioned as a preferable example.
The content of the photopolymerization initiator or the photopolymerization initiator system with respect to the total solid content of the composition for forming an alignment film is generally 0.5 to 20% by mass, and preferably 0.5 to 5% by mass.

It is also preferable to use a cationic polymerization initiator as the polymerization initiator. Examples of cationic polymerization initiators include double salts such as aryldiazonium salts of diacids such as etrafluoroborate and hexafluorophosphenol, diaryliodonium salts and triarylsulfonium salts, benzylsilyl ether, o-nitrobenzylsilyl ether, Examples thereof include a mixed system of a silanol-generating silane compound such as phenyl (t-butyl) peroxysilane and an aluminum complex such as tris (ethylacetoacetate) aluminum. Specifically, diazodisulfone photoacid generators such as WPAG-145, WPAG-170, and WPAG-199 (all manufactured by Wako Pure Chemical Industries), WPAG-281, WPAG-336, and WPAG-367 (all Wako Pure) SB 1A, SB 2B, SB 2B F, SB 3C (all manufactured by Nippon Shibel Hegner), UVI-6974, UVI-6990 (made by Union Carbide), FX512 (made by 3M), KI-85 (made by Degussa) Triarylsulfonium photoacid generators such as WPI-113 (manufactured by Wako Pure Chemical Industries, Ltd.), diaryl iodonium salts such as MC AA, MC BB, MC CC, MC CC PF, MC CC F (all of which are manufactured by Nippon Siebel Hegner), etc. Commercially available photocationic initiators can be used.
The content of the cationic polymerization initiator based on the total solid content of the composition for forming an alignment film is generally 0.5 to 20% by mass, and preferably 0.5 to 5% by mass.

In the composition, a polymerization initiator having two or more different photoreaction mechanisms may be used in combination as a photopolymerization initiator.
In addition, some of the liquid crystal aligning agents undergo polymerization of the polymerizable group by light irradiation even when no polymerization initiator is present. In such a case, the curing step described later can be carried out without using a polymerization initiator.

  The plasticizer is not particularly limited, and various plasticizers can be used. Specifically, phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diaryl phthalate, dimethyl glycol phthalate , Ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, glycol esters such as triethylene glycol dicaprylate, phosphate esters such as tricresyl phosphate, triphenyl phosphate, diisobutyl adipate , Dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate, triethyl citrate, glycerin triacetyl ester, and the like butyl laurate.

  The surfactant is not particularly limited, and various anionic, cationic, nonionic and amphoteric surfactants can be used. Fluorine compounds are particularly preferable, and examples thereof include perfluoroalkylamine oxides, perfluoroalkylethylene oxide adducts, perfluoroalkyl group and hydrophilic group-containing polymers, perfluoroalkyl groups, hydrophilic groups, and lipophilic group-containing polymers.

The alignment film of the present invention includes, for example, a step of forming a film of a composition containing the liquid crystal alignment agent of the present invention (film formation step) and a step of irradiating light to impart a liquid crystal alignment function (light irradiation step). Can be manufactured. When a liquid crystal aligning agent has polymerizability, it is preferable to manufacture through the process (curing process) which advances superposition | polymerization of a polymeric group further. Below, each process is demonstrated concretely.
The film forming process is not particularly limited. For example, it can be formed by preparing the composition as a coating liquid and applying it to the surface of a substrate or the like, followed by drying. As the coating method, known methods such as curtain coating method, extrusion coating method, roll coating method, spin coating method, ink jet method, dip coating method, bar coating method, spray coating method, slide coating method, print coating method, etc. Various methods are employed.

Moreover, you may use the solvent cast method which casts on a drum or a band, evaporates a solvent, and forms a film. A general solvent casting method is described in each specification of US Pat. No. 2,336,310, Japanese Patent Publication No. 45-4554, and the like.
In the solvent cast method, a dope containing the liquid crystal aligning agent at a high concentration is prepared. The solvent used for preparing the dope is not particularly limited. For example, ester solvents such as ethyl acetate, ketone solvents such as methyl ethyl ketone and cyclohexanone, ether solvents such as tetrahydrofuran, halogen solvents such as chloroform and dichloromethane, or dimethylformamide. And amide solvents such as these, and mixed solvents thereof. It is preferable to adjust the concentration of the dope so that the solid content is 0.1 to 10% by mass. The solid content is more preferably 1 to 10% by mass. The dope may be filtered as necessary.

  Two or more dopes can be cast. The surface of the drum or band is preferably finished in a mirror state. The obtained film is peeled off from the drum or band to produce a polymer film. The stripping step may be performed after light irradiation, which is the next step, or after a curing step that is actually performed as desired. Moreover, it can also utilize as an alignment film in the state integrated with the support body, without peeling off.

  In addition, from the viewpoint of patterning, a method of spraying the composition prepared as a fluid on the surface of a substrate or the like to form a film (spray coating method, ink jet method, etc.) is also a preferred example. The ink jet method will be described. The ink jet method is a method in which a small amount of a coating liquid is ejected from a nozzle to adhere a predetermined amount on a support. In the preparation of the fluid, it is preferable to adjust the concentration so that the solid content is 0.5 to 40% by weight. The solid content is more preferably 1 to 30% by weight. A filtration step may be added to the preparation as necessary. The temperature at the time of application is usually a temperature lower than the boiling point of the solvent used in the solution from room temperature.

When the coating film formed by application | coating etc. contains the solvent, you may heat and dry and it is preferable that the temperature at the time of drying is about 40-200 degreeC.
The thickness of the coating film to be formed is not particularly limited, but the thickness after drying after removing the solvent is preferably 0.001 to 1 μm, and more preferably 0.005 to 0.5 μm.

(Light irradiation process)
Next, the formed coating film is irradiated with light to obtain an alignment film having a liquid crystal alignment function.
The preferable range of the wavelength of light to be irradiated varies depending on the liquid crystal aligning agent to be used, and is not particularly limited as long as it is a wavelength necessary for the photoreaction. Preferably, the peak wavelength of light is 200 nm to 700 nm, more preferably ultraviolet light having a peak wavelength of light of 400 nm or less. The preferred range of light intensity varies depending on the liquid crystal aligning agent used, and is not particularly limited. Usually, the range of 1 mJ / cm ^{2 to} 600 J / cm ² is preferable, and the range of 10 mJ / cm ^{2 to} 10 J / cm ² is more preferable. In particular, since the liquid crystal aligning agent of the present invention exhibits a liquid crystal aligning function with a small amount of light irradiation, it is appropriate to perform light irradiation at about 10 mJ / cm ^{2 to 1} J / cm ² .

The light source used for light irradiation is a commonly used light source such as a tungsten lamp, a halogen lamp, a xenon lamp, a xenon flash lamp, a mercury lamp, a mercury xenon lamp, a carbon arc lamp, or various lasers (for example, a semiconductor laser, Helium neon laser, argon ion laser, helium cadmium laser, YAG laser), light emitting diode, cathode ray tube, and the like.
The ultraviolet rays in the preferable wavelength region can be obtained by means of using a filter, a diffraction grating or the like together with the light source. For simplicity, a polarizing plate that does not transmit ultraviolet light having a wavelength shorter than 320 nm, such as a Pyrex (registered trademark) polarizing plate, can be used together with the light source.

  The light irradiation may be non-polarized light or polarized light, but it is preferable to use polarized light, more preferably linearly polarized light. As means for obtaining linearly polarized light, a method using a polarizing plate (for example, an iodine polarizing plate, a dichroic dye polarizing plate, a wire grid polarizing plate), a reflection using a prism-based element (for example, a Glan-Thompson prism) or a Brewster angle. A method using a type polarizer or a method using light emitted from a laser light source having polarization can be employed. Moreover, you may selectively irradiate only the light of the required wavelength using a filter, a wavelength conversion element, etc.

The direction of light irradiation is not particularly limited, and irradiation may be performed from the upper surface or the back surface of the coating film, or may be performed perpendicularly or obliquely to the film surface. Vertical irradiation is preferable. The alignment axis of the formed alignment film (the axis that determines the alignment direction of the liquid crystal molecules arranged on the alignment film) can be adjusted by the direction of the polarization axis of the linearly polarized light irradiated with polarized light.
In addition, you may perform heating operation as needed during light irradiation or after light irradiation.

(Curing process)
As described above, when the liquid crystal aligning agent has a polymerizable group, in order to increase the film strength, the reaction of the polymerizable group is preferably advanced and cured. The reaction of the polymerizable group can proceed by irradiating light again. Light irradiation for curing may be non-polarized light or polarized light, but non-polarized light is preferably used. The wavelength of light used varies depending on the type of liquid crystal aligning agent and the polymerization initiator used as desired, and is not particularly limited as long as it is a wavelength necessary for the photoreaction. Preferably, it is ultraviolet light having a peak wavelength of 400 nm or less. Although it does not restrict | limit especially also about intensity | strength, compared with the said light irradiation process (henceforth a "1st light irradiation process") for providing an orientation function, irradiating higher intensity light. preferable. Light irradiation may be performed under heating.

  Although a polymerization initiator may be contained in the composition in advance, it is preferable to add the polymerization initiator after the first light irradiation step so that curing does not proceed. For example, after performing the first light irradiation step, a fluid containing a polymerization initiator may be applied to the surface of the film, and the polymerization initiator in the liquid may be permeated into the film. The fluid can be prepared by dissolving the polymerization initiator in a solvent. The solvent is not particularly limited, but a solvent that does not dissolve the coating film is employed. Specifically, for example, ester solvents such as ethyl acetate, ketone solvents such as methyl ethyl ketone and cyclohexanone, ether solvents such as tetrahydrofuran, halogen solvents such as chloroform and dichloromethane, or alcohol solvents such as methanol and ethanol, Examples include nitrile solvents such as acrylonitrile and mixed solvents thereof. Alcohol solvents such as methanol and ethanol, and nitrile solvents such as acrylonitrile are particularly preferred. Moreover, you may add a required additive as needed. The solid content of the solution used is preferably 0.1 to 35% by weight, more preferably 0.5 to 25% by weight. The solution to be used may add a filtration process as needed. As the coating method, known methods such as curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, ink jet method, print coating method, etc. Is adopted.

  For the liquid crystal display device, for example, the thickness of the alignment film of the present invention is preferably 0.001 to 2 μm, and more preferably 0.01 to 0.2 μm.

The alignment film of the present invention can be used for various applications. For example, it may be used to form an optically anisotropic film from a liquid crystal composition. Moreover, you may utilize for the orientation control of the liquid crystal in the liquid crystal cell of a liquid crystal display device. Hereinafter, a liquid crystal cell having the alignment film of the present invention will be described.
[Liquid Crystal Cell]
The liquid crystal cell of the present invention is a liquid crystal cell having a pair of substrates and a liquid crystal layer between the pair of substrates, and having the alignment film of the present invention on at least one opposing surface of the pair of substrates. And An alignment film may be provided on both opposing surfaces of the pair of substrates. As the pair of substrates, for example, a glass substrate such as float glass or soda glass, a transparent substrate made of a plastic film such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or the like can be used. .

The said board | substrate may have layers other than the oriented film of this invention in the opposing surface. For example, at least one of the pair of substrates may have a transparent conductive film on the opposing surface. In that case, the alignment film of the present invention may be formed on the transparent conductive film. 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, a method using a mask in advance, or the like is used.
One of the pair of substrates may have a color filter or the like on an opposing surface.

  In addition, when forming an alignment film on the substrate surface, in order to further improve the adhesion between the alignment film and the substrate or a layer such as a transparent conductive film thereon, the substrate or a layer such as a transparent conductive film thereon A functional silane-containing compound, titanate or the like may be applied in advance to the surface.

  The liquid crystal cell of the present invention is produced by sealing the peripheral part between a pair of substrates that are spaced apart and facing each other with a sealing agent, filling the liquid crystal, and sealing the filling hole with the alignment film inside. be able to. The liquid crystal material used is not particularly limited, and for example, nematic liquid crystal, smectic liquid crystal, or the like can be used. In the case of manufacturing a TN liquid crystal cell and an STN liquid crystal cell, it is preferable to use a material having a positive dielectric anisotropy that becomes a nematic liquid crystal. For example, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, and cubane liquid crystal are used. Further, for example, a cholesteric liquid crystal such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate or a chiral agent such as that sold under the trade name C-15, CB-15 (manufactured by Merck) is added to the liquid crystal. It can also be used. Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used. In the case of a vertical alignment type liquid crystal cell, a cell having negative dielectric anisotropy that forms a nematic liquid crystal is preferable. For example, dicyanobenzene liquid crystal, pyridazine liquid crystal, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, and phenylcyclohexane liquid crystal are used.

  As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.

  The manufactured liquid crystal cell is preferably heated to a temperature at which the used liquid crystal takes an isotropic phase, and then cooled to room temperature to remove the flow alignment at the time of injection, and then used for manufacturing a liquid crystal display device.

[Liquid Crystal Display]
The liquid crystal display device of the present invention has the liquid crystal cell of the present invention. An example of the liquid crystal display device of the present invention is a liquid crystal display device having a pair of polarizing plates and the liquid crystal cell of the present invention disposed between the pair of polarizing plates. The liquid crystal display device can be produced by bonding one polarizing plate to each of the two outer substrate surfaces of the liquid crystal cell of the present invention. According to the mode of the liquid crystal display device, the angle between the direction of the polarization axis of the polarizing plate and the orientation axis of the alignment film formed on the opposite surface of the liquid crystal cell substrate is determined, and bonding is performed so as to be the angle. .

When a liquid crystal display device of a twisted alignment mode such as TN or STN is used, a horizontal alignment film is used for the liquid crystal cell. For example, the cell is configured so that the orientation axes of the alignment films formed on the opposing surfaces of the upper and lower substrates are orthogonal to each other, and a polarizing plate is provided on the cell, and the polarization axis is a predetermined angle with the alignment axis of the alignment film. By bonding so as to form a twisted alignment mode liquid crystal display device can be configured.
In the case of a vertical alignment mode liquid crystal display device, a vertical alignment film is used for the liquid crystal cell. The cell is configured such that the orientation axes of the orientation films formed on the opposing surfaces of the upper and lower substrates are parallel to each other, and a polarizing plate is formed on the cell so that the polarization axis forms an angle of 45 degrees with the orientation axis. By bonding, a liquid crystal display device in a vertical alignment mode can be obtained.
The alignment axis of the alignment film can be adjusted by the direction of the polarization axis of linearly polarized light during the first light irradiation step.

  The polarizing plate used outside the liquid crystal cell is a polarizing plate comprising a polarizing film called an H film that absorbs iodine while stretching and aligning polyvinyl alcohol, and a cellulose acetate protective film, or a polarizing film composed of the H film itself. A board etc. can be mentioned.

  Hereinafter, the features of the present invention will be described more specifically with reference to Examples and Comparative Examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

Example 1
First, one ITO (Indium Tin Oxide) electrode (20 mm × 25 mm) was formed on a glass substrate to obtain a substrate with electrodes.

  Next, a 1 mass% tetrahydrofuran solution of the liquid crystal aligning agent (Exemplary Compound P-12) of the present invention was prepared. This solution was applied onto the substrate with electrodes (on the electrode side) by spin coating (3500 rpm, 20 seconds) so that the thickness after drying was about 0.05 to 0.15 μm. A film was formed.

With respect to the obtained organic film, light emitted from ultraviolet light emitted from an ultraviolet irradiator (manufactured by HOYA CANDEO OPTRONICS, EXECURE 3000) is converted into linearly polarized light through a polarizing plate, and is applied to the support. Irradiation was performed for 1 second at an intensity of 100 mW / cm ² (365 nm) from the vertical direction to obtain an alignment film. The irradiation energy was 0.1 J / cm ² .

  The above operation was repeated to prepare a pair of alignment film-attached substrates. After the pair of substrates with alignment films are arranged to face each other via a spacer, the peripheral portions are bonded together, and a product name “Bar-shaped liquid crystal MLC16000-100” manufactured by Merck is injected between the substrates at 100 ° C. Then, a liquid crystal cell was produced. The cell gap was 3 μm. The pair of alignment film-attached substrates were arranged so that the alignment directions of the upper and lower alignment films were parallel.

  When a liquid crystal cell was observed with a polarizing microscope when no voltage was applied, it was confirmed that all liquid crystal molecules were uniaxially aligned and an alignment film free from alignment failure was formed. The major axis direction of the liquid crystal molecules was a direction substantially orthogonal to the polarization axis of the linearly polarized light irradiated to the organic film. When the pretilt angle of the liquid crystal layer was determined by the crystal rotation method, it was 1 °.

(Example 2)
A 1% by mass tetrahydrofuran solution of the liquid crystal aligning agent of the present invention (Exemplary Compound P-3 (x = 0.7, y = 0.3)) was prepared, the irradiation energy was 0.4 J / cm ² , and the organic film A substrate with an alignment film and a liquid crystal cell were prepared in the same manner as in Example 1 except that was formed.

  When evaluation was performed in the same manner as in Example 1, similar results were obtained. That is, it was confirmed that all the liquid crystal molecules were uniaxially aligned, and an alignment film having no alignment failure was formed. The major axis direction of the liquid crystal molecules was a direction substantially orthogonal to the polarization axis of the linearly polarized light irradiated to the organic film. The pretilt angle of the liquid crystal layer was 2 °.

(Example 3)
The liquid crystal aligning agent (exemplary compound P-40) of this invention and 3 mass% of the following polymerization initiators were added with respect to this exemplary compound P-40, and the 1 mass% tetrahydrofuran solution was prepared. This solution was applied onto the substrate with electrodes (on the electrode side) by spin coating (3500 rpm, 20 seconds) so that the thickness after drying was about 0.05 to 0.15 μm. A film was formed.

With respect to the obtained organic film, light emitted from ultraviolet light emitted from an ultraviolet irradiator (manufactured by HOYA CANDEO OPTRONICS, EXECURE 3000) is converted into linearly polarized light through a polarizing plate, and is applied to the support. Irradiation was performed for 1 second at an intensity of 100 mW / cm ² (365 nm) from the vertical direction to obtain an alignment film. The irradiation energy was 0.1 J / cm ² .

Furthermore, with respect to the obtained alignment film, the light emitted from the ultraviolet light emitted from the ultraviolet irradiator (manufactured by HOYA CANDEO OPTRONICS, EXECURE 3000) is 100 mW / cm ² (100 mW / cm ² (from the direction perpendicular to the support). The alignment film was polymerized by irradiating with an intensity of 365 nm) for 15 seconds, and the alignment film was fixed. The irradiation energy was 1.5 J / cm ² .

  The above operation was repeated to prepare a pair of alignment film-attached substrates. After the pair of substrates with alignment films are arranged to face each other via a spacer, the peripheral portions are bonded together, and a product name “Bar-shaped liquid crystal MLC16000-100” manufactured by Merck is injected between the substrates at 100 ° C. Then, a liquid crystal cell was produced. The cell gap was 3 μm. The pair of alignment film-attached substrates were arranged so that the alignment directions of the upper and lower alignment films were parallel.

  When a liquid crystal cell was observed with a polarizing microscope when no voltage was applied, it was confirmed that all liquid crystal molecules were uniaxially aligned and an alignment film free from alignment failure was formed. The major axis direction of the liquid crystal molecules was a direction substantially orthogonal to the polarization axis of the linearly polarized light irradiated to the organic film. When the pretilt angle of the liquid crystal layer was determined by the crystal rotation method, it was 2 °.

Example 4
A 1% by mass tetrahydrofuran solution of the liquid crystal aligning agent of the present invention (Exemplary Compound P-16 (x = 0.9, y = 0.1)) was prepared. This solution was applied onto the substrate with electrodes (on the electrode side) by spin coating (3500 rpm, 20 seconds) so that the thickness after drying was about 0.05 to 0.15 μm. A film was formed.

With respect to the obtained organic film, light emitted from ultraviolet light emitted from an ultraviolet irradiator (manufactured by HOYA CANDEO OPTRONICS, EXECURE 3000) is converted into linearly polarized light through a polarizing plate, and is applied to the support. Irradiation was performed for 10 seconds at an intensity of 100 mW / cm ² (365 nm) from the vertical direction to obtain an alignment film. The irradiation energy was 1.0 J / cm ² . On this alignment film, a methanol solution of 1% by mass photoacid generator (manufactured by Chiba, UVI-6974) was further applied, and ultraviolet light emitted from an ultraviolet irradiator (manufactured by HOYA CANDEO OPTRONICS, EXECURE 3000) was applied. Irradiation was performed for 10 seconds at an intensity of 260 mW / cm ² (365 nm) from a direction perpendicular to the support, the alignment film was polymerized, and the alignment film was fixed. The irradiation energy was 2.6 J / cm ² .

  The above operation was repeated to prepare a pair of alignment film-attached substrates. After the pair of substrates with alignment films are arranged to face each other via a spacer, the peripheral portions are bonded together, and a product name “Bar-shaped liquid crystal MLC16000-100” manufactured by Merck is injected between the substrates at 100 ° C. Then, a liquid crystal cell was produced. The cell gap was 3 μm. The pair of alignment film-attached substrates were arranged so that the alignment directions of the upper and lower alignment films were parallel.

  When a liquid crystal cell was observed with a polarizing microscope when no voltage was applied, it was confirmed that all liquid crystal molecules were uniaxially aligned and an alignment film free from alignment failure was formed. The major axis direction of the liquid crystal molecules was a direction substantially orthogonal to the polarization axis of the linearly polarized light irradiated to the organic film. When the pretilt angle of the liquid crystal layer was determined by the crystal rotation method, it was 1 °.

(Comparative Example 1)
A 1% by mass tetrahydrofuran solution of the polymer 1 described in [0010] and [0015] described in JP-A No. 2000-212310 was prepared, an irradiation energy was set to 0.1 J / cm ² , and an organic film was formed. Except for the above, a substrate with an alignment film and a liquid crystal cell were produced in the same manner as in Example 1.
As a result of evaluation in the same manner as in Example 1, alignment defects due to numerous schlieren defects were confirmed in the alignment of liquid crystal molecules.

(Comparative Example 2)
A substrate with an alignment film and a liquid crystal cell were produced in the same manner as in Comparative Example 1 except that the irradiation energy was 5 J / cm ² and an organic film was formed.
When a liquid crystal cell was observed with a polarizing microscope when no voltage was applied, it was confirmed that all liquid crystal molecules were uniaxially aligned and an alignment film free from alignment failure was formed. When the pretilt angle of the liquid crystal layer was determined by the crystal rotation method, it was 1 °.

(Comparative Example 3)
A 1 mass% 1-methyl-2-pyrrolidinone solution of the compound of Example 3 described in Japanese Patent No. 3612308 (compound described in [0067] of the publication) was prepared, and the irradiation energy was 0.1 J / cm ^2. A substrate with an alignment film and a liquid crystal cell were produced in the same manner as in Example 1 except that an organic film was formed.
As a result of evaluation in the same manner as in Example 1, alignment defects due to numerous schlieren defects were confirmed in the alignment of liquid crystal molecules.

(Comparative Example 4)
A substrate with an alignment film and a liquid crystal cell were produced in the same manner as in Comparative Example 3, except that the irradiation energy was 5 J / cm ² and an organic film was formed.
When a liquid crystal cell was observed with a polarizing microscope when no voltage was applied, it was confirmed that all liquid crystal molecules were uniaxially aligned and an alignment film free from alignment failure was formed. When the pretilt angle of the liquid crystal layer was determined by the crystal rotation method, it was 1 °.

  From comparison between Examples 1 to 4 and Comparative Examples 1 to 4, it is clear that the photo-alignment films of Examples 1 to 4 have high photosensitivity to polarized light irradiation and develop orientation with low irradiation energy. It became.

(Example 5)
Evaluation of Thermal Durability After the alignment films prepared in Example 3, Example 4, and Comparative Example 2 were allowed to stand at 150 ° C. for 10 minutes, a substrate with an alignment film and a liquid crystal cell were manufactured.

  When a liquid crystal cell was observed with a polarizing microscope when no voltage was applied, it was confirmed that in the liquid crystal cells of Example 3 and Example 4, all the liquid crystal molecules were uniaxially aligned and an alignment film having no alignment failure was formed. It was. When the pretilt angle of the liquid crystal layer was determined by the crystal rotation method, it was 1 ° and 4 °, respectively. On the other hand, in the liquid crystal cell of Comparative Example 2, alignment defects due to numerous schlieren defects were confirmed in the alignment of the liquid crystal molecules. From the above results, it has been clarified that the photo-alignment films of Examples 3 and 4 have higher thermal stability than the photo-alignment film of Comparative Example 2.

Claims (8)

A liquid crystal aligning agent comprising a polymer having a repeating unit represented by the following formula (I):

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent;
Y ¹ is the following linking group group (linking group group)
-O -, - CO -, - NR 6 - (R 6 represents a hydrogen atom or an alkyl group), - S-, an alkylene group, and a divalent linking group or a linking group group of the following selected from the arylene group Represents a divalent linking group formed by combining two or more selected from:
Ar ¹ represents a substituted or unsubstituted aromatic ring group having 1 to 10 carbon atoms;
R ⁴ and R ⁵ each independently represents a substituent;
n represents an integer of 1 to 3, p represents an integer of 0 to 4, and q represents an integer of 0 to 5. The liquid crystal aligning agent according to claim 1, wherein q is an integer of 1 or more, and at least one of q R ⁵ is a substituent containing a polymerizable group. A liquid crystal aligning agent characterized by being a polymer having at least a repeating unit represented by the following formula (II) and having at least one polymerizable group:

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent;
Y ¹ is the following linking group group (linking group group)
-O -, - CO -, - NR 6 - (R 6 represents a hydrogen atom or an alkyl group), - S-, an alkylene group, and a divalent linking group or a linking group group of the following selected from the arylene group Represents a divalent linking group formed by combining two or more selected from:
Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aromatic ring group having 1 to 10 carbon atoms;
n represents an integer of 1 to 3. The liquid crystal aligning agent according to claim 1, further comprising at least one repeating unit derived from a (meth) acrylic acid monomer. The liquid crystal aligning agent according to claim 4, wherein the repeating unit derived from the (meth) acrylic acid monomer has at least one polymerizable group. The alignment film containing the liquid crystal aligning agent of any one of Claims 1-5. A liquid crystal cell having a pair of substrates disposed opposite to each other and a liquid crystal layer between the pair of substrates, wherein the alignment film according to claim 6 is provided on at least one facing surface of the pair of substrates. A liquid crystal cell. A liquid crystal display device comprising the liquid crystal cell according to claim 7.