JP2020042288A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

To provide a liquid crystal alignment film to which the ability to control alignment is imparted with high efficiency, and which has a wide range of optimal polarized ultraviolet ray irradiation doses; and a liquid crystal alignment agent for obtaining the film.SOLUTION: In an optically active composition, a (B) component and/or a side chain of an (A) component contains a photoreactive group, and the (A) component and the (B) component form a liquid crystal supramolecule via hydrogen bonds; where (A) is a polymer that has a side chain containing a carboxylic acid group structure, and (B) is at least one compound selected from compounds represented by the formulas (1) and (2) in the figure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display device using the same, and a polymer film suitable for producing an optical device with controlled molecular alignment such as a retardation film or a polarization diffraction device. .

  2. Description of the Related Art Liquid crystal display elements are known as light-weight, thin, and low-power-consumption display devices, and have been remarkably developed in recent years, such as being used for large-sized televisions. The liquid crystal display element is configured, for example, by sandwiching a liquid crystal layer between a pair of transparent substrates provided with electrodes. In the liquid crystal display device, an organic film made of an organic material is used as a liquid crystal alignment film so that the liquid crystal is in a desired alignment state between the substrates.

  That is, the liquid crystal alignment film is a constituent member of the liquid crystal display element, and is formed on a surface of the substrate that sandwiches the liquid crystal, in contact with the liquid crystal, and has a role of aligning the liquid crystal in a certain direction between the substrates. The liquid crystal alignment film may be required to have a role of controlling the pretilt angle of the liquid crystal in addition to a role of aligning the liquid crystal in a fixed direction, for example, a direction parallel to the substrate. The ability of such a liquid crystal alignment film to control the alignment of liquid crystal (hereinafter, referred to as alignment control ability) is given by performing an alignment process on an organic film constituting the liquid crystal alignment film.

  A rubbing method is conventionally known as an alignment treatment method for a liquid crystal alignment film for imparting alignment control ability. The rubbing method is a method of rubbing (rubbing) the surface of an organic film such as polyvinyl alcohol, polyamide, or polyimide on a substrate with a cloth of cotton, nylon, polyester, or the like in a certain direction, and in a rubbing direction (rubbing direction). This is a method of aligning liquid crystals. Since this rubbing method can easily realize a relatively stable alignment state of liquid crystal, it has been used in a conventional liquid crystal display element manufacturing process. As the organic film used for the liquid crystal alignment film, a polyimide organic film excellent in reliability such as heat resistance and electrical characteristics has been mainly selected.

  However, the rubbing method of rubbing the surface of a liquid crystal alignment film made of polyimide or the like sometimes causes problems such as generation of dust and static electricity. In addition, the surface of the liquid crystal alignment film cannot be uniformly rubbed with a cloth due to the recent increase in definition of the liquid crystal display element and unevenness due to the corresponding electrodes on the substrate and switching active elements for driving the liquid crystal. In some cases, liquid crystal alignment could not be realized.

  Therefore, as another alignment treatment method for a liquid crystal alignment film that does not perform rubbing, a photo alignment method has been actively studied.

  There are various photoalignment methods. Anisotropy is formed in the organic film constituting the liquid crystal alignment film by linearly polarized light or collimated light, and the liquid crystal is aligned according to the anisotropy. The main alignment methods are "photolysis type", which causes anisotropic decomposition of the molecular structure by irradiation with polarized ultraviolet light, or polyvinyl cinnamate, which is irradiated with polarized ultraviolet light and the two sides parallel to the polarized light. When a dimerization reaction (cross-linking reaction) is caused at a double bond portion of a chain (for example, see Patent Document 1), and a side chain type polymer having azobenzene in a side chain is used. Irradiates polarized ultraviolet light to cause an isomerization reaction in the azobenzene portion of the side chain parallel to the polarized light, and orients the liquid crystal in a direction orthogonal to the polarization direction (for example, see Non-Patent Document 2). It is known.

  On the other hand, in recent years, a new photo-alignment method (hereinafter, also referred to as an alignment amplification method) using a photosensitive side-chain polymer that can exhibit liquid crystallinity has been studied. In this method, a film having a photosensitive side-chain polymer capable of exhibiting liquid crystallinity is subjected to an alignment treatment by irradiating polarized light, and then, through a step of heating the side-chain polymer film, the alignment control ability is improved. The purpose is to obtain the applied coating film. At this time, the slight anisotropy developed by the polarized light irradiation becomes a driving force, and the liquid crystal side chain polymer itself is efficiently realigned by self-organization. As a result, highly efficient alignment treatment is realized as the liquid crystal alignment film, and a liquid crystal alignment film with high alignment control ability can be obtained (for example, see Patent Document 2).

  Furthermore, since the polymer film obtained by this orientation amplification method exhibits birefringence due to molecular orientation, it can be used not only for liquid crystal alignment films but also for various optical elements such as retardation films. it can.

Japanese Patent No. 3893659 WO2014 / 054785

M. Shadt et al., Jpn. J. Appl. Phys. 31, 2155 (1992) K. Ichimura et al., Chem. Rev. 100, 1847 (2000)

  The optimal amount of polarized ultraviolet light to introduce highly efficient anisotropy into the liquid crystal alignment film used in the alignment amplification method is the amount of polarized ultraviolet light that optimizes the amount of photoreactive groups in the coating film. Corresponding to As a result of irradiating polarized ultraviolet light to the liquid crystal alignment film used in the alignment amplification method, if the number of photoreactive side-chain photosensitive groups is small, the amount of photoreaction will not be sufficient. In that case, even after heating, sufficient self-organization does not proceed. On the other hand, if the photoreactive side-chain photosensitive group becomes excessive, the resulting film becomes rigid, which may hinder the progress of self-assembly by subsequent heating.

  At present, some of the liquid crystal alignment films used in the alignment amplification method have a narrow range of the optimal amount of polarized ultraviolet light irradiation because of the high sensitivity of the photoreactive group in the polymer used. is there. As a result, there is a problem that the manufacturing efficiency of the liquid crystal display element is reduced.

  Further, when the firing temperature of the liquid crystal alignment film is low, the reliability of the liquid crystal display element may be reduced due to the influence of the residual solvent and the like. Since sintering cannot be performed at a temperature higher than the liquid crystal development temperature, the sintering temperature is low as a whole, and the residual solvent and the like contribute to lower reliability.

  Accordingly, an object of the present invention is to provide a liquid crystal alignment film having a wide process margin, which is provided with an alignment control ability with high efficiency and can be adjusted to an optimum irradiation amount of polarized ultraviolet light and an optimum firing temperature.

  The present inventors have conducted intensive studies to achieve the above object, and as a result, have found the following invention.

<1> It contains the following components (A) and (B), and a photoreactive group is contained in one or both of the side chain of the component (A) and the component (B). An optically active composition wherein the component (B) forms a liquid crystalline supramolecule via a hydrogen bond.
(A) a polymer having a side chain containing a carboxylic acid group structure, and (B) at least one kind of aromatic heterocyclic compound represented by the following formula (1) or (2), pyrazine and naphthyridine: Compound:

[Where,
X represents a single bond or alkylene having 1 to 12 carbon atoms, ether, ester, azo, thioether, disulfide, tetrazine, disubstituted alkene, alkyne, or phenylene;
S represents ether, ester or phenylene,
Py each independently represents a structure selected from the following group. In the following structures, a dotted portion is a portion that bonds to X in the formula (1) and bonds to S in the formula (2). Part.

］。

].

  <2> In the optically active composition of <1>, the component (A) preferably contains a carboxylic acid group and a photoreactive group in one side chain structure.

  <3> In the optically active composition of <1> or <2>, the component (B) is contained in an amount of 0.5% by weight to 70% by weight based on the weight of the polymer of the component (A). Is good.

  <4> In the optically active composition according to any one of <1> to <3>, the component (A) is any one carboxylic acid selected from the group consisting of the following formulas (3) and (4). A polymer having a side chain containing a group structure is preferred.

[Where,
A represents a single bond, -O-, -COO-, -CONH-, and a group selected from -NH-,
B represents a single bond, -O-, -COO-, -CONH-, -NH-, and a group selected from -CH = CH-COO-,
Ar ₁ and Ar ₂ each independently represent a phenyl group or a naphthyl group;
l and m are each independently an integer from 0 to 12].

<5> In the optically active composition according to any one of the above items <1> to <4>, the component (B) is preferably at least one compound selected from the following.

［式中、
ｎは、１から３の整数を表し、
ｌは、２から６の整数を表し、及び
ｍは、１から４の整数を表す］。

[Where,
n represents an integer of 1 to 3,
l represents an integer from 2 to 6 and m represents an integer from 1 to 4].

<6> A liquid crystal aligning agent containing the optically active composition according to any one of <1> to <5>.
<7> A liquid crystal alignment film obtained from the liquid crystal alignment agent of <6>.
<8> A liquid crystal display device comprising the liquid crystal alignment film according to <7>.

  According to the present invention, an optically active composition, which is provided with an alignment control ability with high efficiency, and has a wide range of the optimal amount of polarized ultraviolet light irradiation, or a liquid crystal development temperature of a polymer liquid crystal can be suitably selected. The present invention can provide a liquid crystal alignment agent containing a substance, a liquid crystal alignment film obtained from the liquid crystal alignment agent, a substrate having the liquid crystal alignment film, and a horizontal electric field driven liquid crystal display device having the substrate. Further, by using the optically active composition, it is possible to provide a polymer film having a wide process margin (a polarized ultraviolet ray irradiation amount and a sintering temperature) in the production of an optical element for a retardation film or the like.

FIG. 1 is a graph showing the dichroism obtained from Example 8 and Comparative Example 2. FIG. 2 is a graph showing the degree of in-plane orientation S at each dose obtained from Example 10 and Comparative Example 3.

Hereinafter, embodiments of the present invention will be described in detail.
<Optically active composition>
The optically active composition of the present invention contains the following components (A) and (B), and contains a photoreactive group in one or both of the components (A) and (B); The component and the component (B) form a liquid crystal supramolecule via a hydrogen bond.
(A) a polymer having a side chain containing a carboxylic acid group structure, and (B) at least one compound selected from compounds represented by the following formulas (1) and (2):

[Where,
X represents a single bond or alkylene having 1 to 12 carbon atoms, ether, ester, azo, thioether, disulfide, tetrazine, disubstituted alkene, alkyne, and phenylene;
S represents ether, ester or phenylene,
Py each independently represents a structure selected from the following group. In the following structures, a dotted portion is a portion that bonds to X in the formula (1) and bonds to S in the formula (2). Part.

］。

].

  Although it is not clear why the composition satisfying the above constitutional requirements has the effect of solving the problem of the present invention, it is generally considered as follows.

  It is said that the polymer having a side chain containing a carboxylic acid group structure, which is the component (A) in the present invention, shows a supramolecular liquid crystal by a hydrogen bond between carboxylic acids. In such a supramolecular liquid crystal, the structure of the aromatic ring-carboxylic acid-carboxylic acid-aromatic ring forming a hydrogen bond has a mesogenic structure as shown below, and a temperature range showing liquid crystallinity, ultraviolet light, It is considered that the absorption band and the like are almost determined by this mesogen site.

  At this time, when the aromatic heterocyclic structure as the component (B) of the present invention exists, a part of the carboxylic acid forms a mesogenic structure by hydrogen bonding (or interaction such as ionic bonding) with the heterocyclic ring, and Sex will be expressed. As a result, the temperature range showing the liquid crystallinity, the ultraviolet absorption band, and the like change. In the present invention, by freely selecting these combinations, it becomes possible to adjust the temperature range in which the liquid crystal is developed, the sensitivity to ultraviolet light, and the like to an arbitrary range. Note that these are theories and do not restrict the present invention.

<< (A) component >>
The component (A) is a polymer having a side chain containing a carboxylic acid group structure. At this time, the carboxylic acid group and the photoreactive group may be contained in one side chain structure, or another side chain containing a photoreactive group may be present in the polymer. It is preferred that one side chain structure contains a carboxylic acid group and a photoreactive group from the viewpoint of product reaction efficiency.

  When a carboxylic acid group and a photoreactive group are contained in one side chain structure, the general formula of the side chain (hereinafter also referred to as a specific side chain) can be represented by the above formulas (3) and (4). .

In the above formulas (3) and (4), A represents a group selected from a single bond, -O-, -COO-, -CONH-, and -NH-, and among them, -O- from the viewpoint of exhibiting liquid crystallinity. , -COO- is preferred.
In the above formulas (3) and (4), B represents a group selected from a single bond, -O-, -COO-, -CONH-, -NH-, and -CH = CH-COO-. Among them, -O- and -COO- are preferable from the viewpoint of exhibiting liquid crystallinity.

  Ar1 and Ar2 each independently represent a phenyl group or a naphthyl group.

l and m are each independently an integer of 0 to 12. Among them, from the viewpoint of liquid crystal expression,
An integer from 2 to 8 is preferred.

  Specific examples of the side chain structure represented by the above formulas (3) and (4) are exemplified as follows, but are not limited thereto.

  In the formula, m represents an integer of 2 to 12.

<< polymer production method >>
The polymer of the component (A) can be obtained by a polymerization reaction of the above-mentioned monomer containing a specific side chain. Further, it can also be obtained by copolymerization of a monomer having a side chain containing a photoreactive group and a monomer having a side chain containing a carboxylic acid group. Furthermore, it can be copolymerized with other monomers as long as the ability to exhibit liquid crystallinity is not impaired.
Examples of other monomers include, for example, commercially available monomers capable of undergoing a radical polymerization reaction.

  Specific examples of other monomers include unsaturated carboxylic acids, acrylate compounds, methacrylate compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds, vinyl compounds, and the like.

  Specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the like.

  As the acrylate compound, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl acrylate, anthryl methyl acrylate, phenyl acrylate, 2,2,2-trifluoroethyl acrylate, tert-butyl Acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2- Propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate, and , Etc. 8-ethyl-8-tricyclodecyl acrylate.

  Examples of the methacrylate compound include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate, and tert-butyl. Methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2- Propyl-2-adamantyl methacrylate, 8-methyl 8 tricyclodecyl methacrylate, and, 8-ethyl-8-tricyclodecyl methacrylate. (Meth) acrylate compounds having a cyclic ether group such as glycidyl (meth) acrylate, (3-methyl-3-oxetanyl) methyl (meth) acrylate, and (3-ethyl-3-oxetanyl) methyl (meth) acrylate are also used. be able to.

  Examples of the vinyl compound include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.

  Examples of the styrene compound include styrene, methylstyrene, chlorostyrene, bromostyrene and the like.

  Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

  The method for producing the polymer of the component (A) is not particularly limited, and a general-purpose method used industrially can be used. Specifically, it can be produced by cationic polymerization, radical polymerization, or anionic polymerization using a vinyl group of a specific side chain monomer. Among these, radical polymerization is particularly preferred from the viewpoint of easy reaction control.

  As the polymerization initiator for radical polymerization, known compounds such as a radical polymerization initiator and a reversible addition-cleavage chain transfer (RAFT) polymerization reagent can be used.

  The radical thermal polymerization initiator is a compound that generates a radical when heated to a temperature higher than the decomposition temperature. Examples of such a radical thermal polymerization initiator include ketone peroxides (eg, methyl ethyl ketone peroxide, cyclohexanone peroxide), diacyl peroxides (eg, acetyl peroxide, benzoyl peroxide), and hydroperoxides (eg, peroxides). Hydrogen, tert-butylhydroxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyketals (dibutylperoxy cyclohexane) Etc.), alkyl peresters (peroxyneodecanoic acid-tert-butyl ester, peroxypivalic acid-tert-butyl ester, peroxy-2-ethylcyclohexane) Sannic acid-tert-amyl ester, etc.), persulfates (potassium persulfate, sodium persulfate, ammonium persulfate, etc.), azo compounds (azobisisobutyronitrile, and 2,2'-di (2-hydroxyethyl ) Azobisisobutyronitrile). One of these radical thermal polymerization initiators can be used alone, or two or more can be used in combination.

  The radical photopolymerization initiator is not particularly limited as long as it is a compound that initiates radical polymerization by light irradiation. Examples of such a radical photopolymerization initiator include benzophenone, Michler's ketone, 4,4′-bis (diethylamino) benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, and 2-hydroxy -2-methylpropiophenone, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexylphenylketone, isopropylbenzoin ether, isobutylbenzoin ether, 2,2-diethoxyacetophenone, 2,2 -Dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2- Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,4-dimethylaminoethyl benzoate, isoamyl 4-dimethylaminobenzoate, 4,4′-di (t-butylperoxycarbonyl) benzophenone , 3,4,4'-tri (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2- (4'-methoxystyryl) -4,6-bis (trichloromethyl) -S-triazine, 2- (3 ', 4'-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2', 4'-dimethoxystyryl) -4,6-bis (Trichloromethyl) -s-triazine, 2- (2'-methoxystyryl) -4,6-bis (trichloromethyl ) -S-Triazine, 2- (4′-pentyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 4- [pN, N-di (ethoxycarbonylmethyl)]-2, 6-di (trichloromethyl) -s-triazine, 1,3-bis (trichloromethyl) -5- (2′-chlorophenyl) -s-triazine, 1,3-bis (trichloromethyl) -5- (4 ′ -Methoxyphenyl) -s-triazine, 2- (p-dimethylaminostyryl) benzoxazole, 2- (p-dimethylaminostyryl) benzothiazole, 2-mercaptobenzothiazole, 3,3'-carbonylbis (7-diethylamino Coumarin), 2- (o-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bi (2-chlorophenyl) -4,4 ', 5,5'-tetrakis (4-ethoxycarbonylphenyl) -1,2'-biimidazole, 2,2'-bis (2,4-dichlorophenyl) -4, 4 ', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'bis (2,4-dibromophenyl) -4,4', 5,5'-tetraphenyl-1,2 ' -Biimidazole, 2,2'-bis (2,4,6-trichlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, 3- (2-methyl-2 -Dimethylaminopropionyl) carbazole, 3,6-bis (2-methyl-2-morpholinopropionyl) -9-n-dodecylcarbazole, 1-hydroxycyclohexylphenyl ketone, bis (5-2,4-cyclopentadi 1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone 3,3 ', 4,4'-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3'-di (methoxycarbonyl) -4,4'-di (t-butylperoxycarbonyl) benzophenone, 3,4 '-Di (methoxycarbonyl) -4,3'-di (t-butylperoxycarbonyl) benzophenone, 4,4'-di (methoxycarbonyl) -3,3'-di (t-butylperoxycarbonyl) benzophenone, -(3-methyl-3H-benzothiazol-2-ylidene) -1-naphthalen-2-yl-ethanone, or 2- (3-methyl-1 3- benzothiazol -2 (3H) - ylidene) -1- (2-benzoyl) ethanone, and the like. These compounds may be used alone or in combination of two or more.

  The radical polymerization method is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a precipitation polymerization method, a bulk polymerization method, a solution polymerization method, or the like can be used.

  The organic solvent used for the polymerization reaction is not particularly limited as long as the produced polymer can be dissolved. Specific examples are given below.

  N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide , Γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl Carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene Glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, trifluoropropyl Glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n- Hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, Ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion , 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy —N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like.

  These organic solvents may be used alone or as a mixture. Further, even if the solvent does not dissolve the produced polymer, it may be mixed with the above-mentioned organic solvent and used as long as the produced polymer does not precipitate.

In addition, since oxygen in an organic solvent causes inhibition of the polymerization reaction in radical polymerization, it is preferable to use a degassed organic solvent as much as possible.
The polymerization temperature at the time of radical polymerization can be selected from any temperature of 30C to 150C, but is preferably in the range of 50C to 100C. In addition, the reaction can be performed at any concentration, but if the concentration is too low, it is difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring is difficult. Therefore, the monomer concentration is preferably 1% by mass to 50% by mass, and more preferably 5% by mass to 30% by mass. The initial stage of the reaction is carried out at a high concentration, after which an organic solvent can be added.
In the above-described radical polymerization reaction, when the ratio of the radical polymerization initiator to the monomer is large, the molecular weight of the obtained polymer is small, and when the ratio is small, the molecular weight of the obtained polymer is large. The amount is preferably from 0.1 mol% to 10 mol% based on the monomer to be polymerized. At the time of polymerization, various monomer components, a solvent, an initiator and the like can be added.

[Recovery of polymer]
When recovering the produced polymer from the polymer reaction solution obtained by the above reaction, the polymer may be precipitated by adding the reaction solution to a poor solvent. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, heptane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, water and the like. The polymer that has been put into a poor solvent and precipitated can be collected by filtration and then dried at normal temperature or reduced pressure at normal temperature or by heating. Further, by repeating the operation of re-dissolving the polymer recovered by precipitation in an organic solvent and recovering and recovering the precipitate two to ten times, impurities in the polymer can be reduced. In this case, examples of the poor solvent include alcohols, ketones, and hydrocarbons. It is preferable to use three or more kinds of poor solvents selected from these, because the purification efficiency is further increased.

  The molecular weight of the polymer of the component (A) of the present invention was measured by a GPC (Gel Permeation Chromatography) method in consideration of the strength of the obtained coating film, workability in forming the coating film, and uniformity of the coating film. The weight average molecular weight is preferably 2,000 to 1,000,000, more preferably 5,000 to 100,000.

<< B component >>
The optically active composition of the present invention contains at least one compound selected from the compounds represented by the following formula (1) or (2) as the component (B).

  In the above formulas (1) and (2), X represents a single bond or an alkylene having 1 to 12 carbon atoms, ether, ester, azo, thioether, disulfide, tetrazine, disubstituted alkene, alkyne, or phenylene; Preferably, it represents an ester, azo, disubstituted alkene or alkyne. Here, the “disubstituted alkene” refers to a disubstituted alkene having 2 to 6, preferably 2 to 4 carbon atoms, and the substituent of the disubstituted alkene is an alkyl group having 1 to 5 carbon atoms, fluorine, or Represents a cyano group.

  In the above formulas (1) and (2), S represents ether, ester or phenylene, preferably phenylene.

  In the above formulas (1) and (2), Py independently represents a structure selected from the following group. In the following structure, a dotted portion is a portion that bonds to X in Formula (1) and a portion that bonds to S in Formula (2). Preferred Py is 4-pyridyl, 4-pyridylphenyl.

  Specific examples of the compounds represented by the above formulas (1) and (2) are shown below, but are not limited thereto.

[Where,
n represents an integer of 1 to 3,
l represents an integer from 2 to 6 and m represents an integer from 1 to 4].

  In addition, from a viewpoint of liquid crystal expression, B1 to B9, B16, and B18 are preferable, and B1 to B5 are more preferable.

  The component (B) is preferably contained in an amount of 0.5% by weight to 70% by weight, more preferably 5% by weight to 50% by weight, based on the weight of the polymer of the component (A). .

  The same effect can be obtained by using the following compound as the component (B).

<Preparation of optically active composition>
The optically active composition used in the present invention is preferably prepared as a coating solution so as to be suitable for forming a coating film. That is, it is preferably prepared as a solution in which the A component, the B component, and various additives described below, which are added as needed, are dissolved in an organic solvent. At this time, the content of the component (hereinafter, also referred to as a resin component) obtained by summing the component A, the component B, and various additives added as necessary is preferably 1% by mass to 20% by mass, more preferably 3% by mass. It is from 15% by mass to 15% by mass, particularly preferably from 3% by mass to 10% by mass.

<Organic solvent>
The organic solvent used in the optically active composition of the present invention is not particularly limited as long as the organic solvent dissolves the resin component. Specific examples are given below.

  N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, Dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, 1,3 -Dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4 Methyl-2-pentanone, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl Ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, etc. Is mentioned. These may be used alone or as a mixture.

  The polymer contained in the optically active composition of the present invention may be a polymer having a side chain containing a carboxylic acid group structure as described above, as long as the liquid crystal expression ability and the photosensitive performance are not impaired. Other polymers than those may be mixed. At that time, the content of the other polymer in the resin component is 0.5% by mass to 80% by mass, preferably 1% by mass to 50% by mass.

  Examples of such another polymer include a polymer made of poly (meth) acrylate, polyamic acid, polyimide, or the like, which is not a photosensitive side-chain polymer capable of exhibiting liquid crystallinity.

The optically active composition of the present invention may contain components other than the components (A) and (B). Examples thereof include, when a solution of the optically active composition is applied, a solvent or a compound for improving the film thickness uniformity or surface smoothness, a compound for improving the adhesion between the coating film and the substrate, and the like. However, the present invention is not limited to this.
Specific examples of the solvent (poor solvent) for improving the uniformity of the film thickness and the surface smoothness include the following.

  For example, isopropyl alcohol, methoxymethyl pentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoacetate Isopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, die Lenglycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene , Propyl ether, dihexyl ether, 1-hexanol, -Hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, 3-methoxy Methyl propionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2 -Propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether -2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate Solvents having a low surface tension, such as esters and isoamyl lactate, are exemplified.

  These poor solvents may be used alone or in combination of two or more. When the above-mentioned solvent is used, it is preferably from 5% by mass to 80% by mass of the whole solvent so as not to significantly lower the solubility of the whole solvent contained in the optically active composition of the present invention. , More preferably 20% by mass to 60% by mass.

  Examples of the compound that improves the uniformity of the film thickness and the surface smoothness include a fluorine-based surfactant, a silicone-based surfactant, and a nonion-based surfactant.

  More specifically, for example, F-top (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products), Megafac (registered trademark) F171, F173, R-30 (manufactured by DIC), Florard FC430, FC431 (Manufactured by Sumitomo 3M), Asahi Guard (registered trademark) AG710 (manufactured by Asahi Glass Co., Ltd.), Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by AGC Seimi Chemical Co., Ltd.) and the like. Can be The use ratio of these surfactants is preferably from 0.01 to 2 parts by mass, more preferably from 0.01 to 1 part by mass, per 100 parts by mass of the resin component contained in the polymer composition. Parts by weight.

  Specific examples of the compound that improves the adhesion between the coating film and the substrate include the following functional silane-containing compounds.

  For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-to Ethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyl triacetate Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-amino Propyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, and the like.

  Furthermore, in addition to improving the adhesion between the substrate and the coating film, the following phenoplast or epoxy group-containing compound additives are used for the purpose of preventing a decrease in electric characteristics due to a backlight when a liquid crystal display element is formed. May be contained in the optically active composition of the present invention. Specific phenoplast-based additives are shown below, but are not limited to this structure.

  Specific epoxy group-containing 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, 6-hexanediol 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'-diaminodiphenylmethane and the like.

  When a compound that improves the adhesion to the substrate is used, the amount used is preferably 0.1 part by mass to 30 parts by mass with respect to 100 parts by mass of the resin component contained in the optically active composition. And more preferably 1 to 20 parts by mass. If the amount is less than 0.1 part by mass, the effect of improving the adhesion cannot be expected. If the amount exceeds 30 parts by mass, the orientation of the liquid crystal may be deteriorated.

  A photosensitizer can also be used as an additive. Colorless and triplet sensitizers are preferred.

As photosensitizers, aromatic nitro compounds, coumarin (7-diethylamino-4-methylcoumarin, 7-hydroxy-4-methylcoumarin), ketocoumarin, carbonylbiscoumarin, aromatic 2-hydroxyketone, and amino-substituted , Aromatic 2-hydroxyketone (2-hydroxybenzophenone, mono- or di-p- (dimethylamino) -2-hydroxybenzophenone), acetophenone, anthraquinone, xanthone, thioxanthone, benzanthrone, thiazoline (2-benzoylmethylene-3) -Methyl-β-naphthothiazoline, 2- (β-naphthoylmethylene) -3-methylbenzothiazoline, 2- (α-naphthoylmethylene) -3-methylbenzothiazoline, 2- (4-biphenoylmethylene)- 3-methylbenzothia Phosphorus, 2- (β-naphthoylmethylene) -3-methyl-β-naphthothiazoline, 2- (4-biphenoylmethylene) -3-methyl-β-naphthothiazoline, 2- (p-fluorobenzoylmethylene)- 3-methyl-β-naphthothiazoline), oxazoline (2-benzoylmethylene-3-methyl-β-naphthooxazoline, 2- (β-naphthoylmethylene) -3-methylbenzooxazoline, 2- (α-naphthoylmethylene) ) -3-Methylbenzoxazoline, 2- (4-biphenoylmethylene) -3-methylbenzoxazoline, 2- (β-naphthoylmethylene) -3-methyl-β-naphthoxazoline, 2- (4-biphenoyl Methylene) -3-methyl-β-naphthoxazoline, 2- (p-fluorobenzoylmethylene) -3-methyl-β- Futoxazoline), benzothiazole, nitroaniline (m- or p-nitroaniline, 2,4,6-trinitroaniline) or nitroacenaphthene (5-nitroacenaphthene), (2-[(m-hydroxy-p -Methoxy) styryl] benzothiazole, benzoin alkyl ether, N-alkylated phthalone, acetophenone ketal (2,2-dimethoxyphenylethanone), naphthalene, anthracene (2-naphthalenemethanol, 2-naphthalenecarboxylic acid, 9-anthracenemethanol , And 9-anthracene carboxylic acid), benzopyran, azoindolizine, melocoumarin and the like.

  Preferably, aromatic 2-hydroxyketone (benzophenone), coumarin, ketocoumarin, carbonylbiscoumarin, acetophenone, anthraquinone, xanthone, thioxanthone, and acetophenone ketal.

  In the optically active composition of the present invention, in addition to those described above, as long as the effects of the present invention are not impaired, for the purpose of changing the electrical properties such as the dielectric constant and conductivity of the coating film, a dielectric or conductive material may be used. A cross-linkable compound may be added for the purpose of increasing the hardness of the film, or the density of the film when formed into a coating film.

  The coating film obtained by applying and baking the above-described optically active composition to a substrate can be used, for example, as a liquid crystal alignment film. The method for applying the liquid crystal aligning agent containing the optically active composition of the present invention on a substrate having a conductive film for driving a lateral electric field is not particularly limited.

  The method of application is industrially generally performed by screen printing, offset printing, flexographic printing, an inkjet method, or the like. Other coating methods include a dip method, a roll coater method, a slit coater method, a spinner method (rotational coating method), and a spray method, and these may be used according to the purpose.

<< Manufacture of liquid crystal display element >>
<Step [I]>
The production of a liquid crystal display device using a liquid crystal alignment agent containing the optically active composition of the present invention is represented by the following steps [I] to [IV]. First, the step [I] is a step of applying the liquid crystal alignment agent of the present invention on a substrate having a conductive film. After the application, the solvent can be evaporated at 50 to 200 ° C., preferably 50 to 150 ° C. by a heating means such as a hot plate, a thermal circulation oven or an IR (infrared) oven to obtain a coating film. The drying temperature at this time is preferably lower than the liquid crystal phase onset temperature of the side chain type polymer.

If the thickness of the coating film is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, the thickness is preferably 5 nm to 300 nm, more preferably 10 nm to 150 nm. It is.
It is also possible to provide a step of cooling the substrate on which the coating film is formed to room temperature after the step [I] and before the subsequent step [II].

<Step [II]>
In the step [II], the coating film obtained in the step [I] is irradiated with polarized ultraviolet light. When irradiating polarized ultraviolet light to the film surface of the coating film, the substrate is irradiated with polarized ultraviolet light from a certain direction via a polarizing plate. As an ultraviolet ray to be used, an ultraviolet ray having a wavelength in the range of 100 nm to 400 nm can be used. Preferably, an optimal wavelength is selected via a filter or the like depending on the type of the coating film to be used. Then, for example, ultraviolet rays having a wavelength in the range of 290 nm to 400 nm can be selected and used so that a photocrosslinking reaction can be selectively induced. As the ultraviolet light, for example, light emitted from a high-pressure mercury lamp can be used.

  The dose of the polarized ultraviolet light depends on the coating film used. The irradiation amount is a polarized ultraviolet ray which realizes a maximum value of ΔA (hereinafter, also referred to as ΔAmax) which is a difference between the ultraviolet ray absorbance in a direction parallel to the polarization direction of the polarized ultraviolet ray and the ultraviolet ray absorbance in a perpendicular direction in the coating film. Is preferably in the range of 1% to 70% of the amount, and more preferably in the range of 1% to 50%.

<Step [III]>
In step [III], the coating film irradiated with the ultraviolet light polarized in step [II] is heated. Heating can impart orientation controllability to the coating film.
For heating, a heating means such as a hot plate, a thermal circulation oven, or an IR (infrared) oven can be used. The heating temperature can be determined in consideration of the temperature at which liquid crystallinity of the coating film used is developed.

  The heating temperature is preferably within a temperature range at which the side chain type polymer exhibits liquid crystallinity (hereinafter, referred to as liquid crystal development temperature). In the case of a thin film surface such as a coating film, the liquid crystal development temperature of the coating film surface is expected to be lower than the liquid crystal development temperature when a photosensitive side-chain polymer capable of developing liquid crystallinity is observed in bulk. You. For this reason, the heating temperature is more preferably within the temperature range of the liquid crystal development temperature on the coating film surface. That is, the temperature range of the heating temperature after the irradiation of the polarized ultraviolet rays is a lower limit of 10 ° C. lower than the lower limit of the temperature range of the liquid crystal development temperature of the side chain type polymer to be used, and a temperature lower by 10 ° C. than the upper limit of the liquid crystal temperature range. It is preferable that the temperature be in the range of the upper limit. When the heating temperature is lower than the above temperature range, the effect of amplifying the anisotropy due to heat in the coating film tends to be insufficient, and when the heating temperature is too high than the above temperature range, the state of the coating film Tends to be close to an isotropic liquid state (isotropic phase), and in this case, it may be difficult to reorient in one direction due to self-organization.

The liquid crystal development temperature is equal to or higher than the glass transition temperature (Tg) at which the side chain type polymer or the surface of the coating film undergoes a phase transition from a solid phase to a liquid crystal phase, and changes from a liquid crystal phase to an isotropic phase (isotropic phase). A temperature below the isotropic phase transition temperature (Tiso) at which phase transition occurs.
The thickness of the coating film formed after heating is preferably 5 nm to 300 nm, more preferably 50 nm to 150 nm, for the same reason as described in the step [I].

  By having the above steps, the production method of the present invention can realize highly efficient introduction of anisotropy into a coating film. Then, a substrate with a liquid crystal alignment film can be manufactured with high efficiency.

<Step [IV]>
In the step [IV], the substrate having the liquid crystal alignment film obtained in the step [III] is opposed to the liquid crystal alignment film via the liquid crystal so that the two liquid crystal alignment films face each other, and a liquid crystal cell is manufactured by a known method. This is a step of manufacturing a liquid crystal display element.

  To give an example of the production of a liquid crystal cell or a liquid crystal display element, two substrates are prepared, and spacers are scattered on the liquid crystal alignment film of one of the substrates so that the liquid crystal alignment film surface is on the inside, Examples include a method in which the other substrate is attached and sealing is performed by injecting liquid crystal under reduced pressure, or a method in which liquid crystal is dropped on the surface of the liquid crystal alignment film on which spacers are scattered and then the substrates are attached and sealed. can do. At this time, it is preferable to use a substrate having an electrode having a structure like a comb for driving a lateral electric field as the substrate on one side. The diameter of the spacer at this time is preferably 1 μm to 30 μm, more preferably 2 μm to 10 μm. This spacer diameter determines the distance between the pair of substrates that sandwich the liquid crystal layer, that is, the thickness of the liquid crystal layer.

In the method for producing a substrate with a coating film of the present invention, a polymer composition is applied on a substrate to form a coating film, and then irradiated with polarized ultraviolet light. Next, by heating, a highly efficient introduction of anisotropy into the side chain type polymer film is realized, and a substrate with a liquid crystal alignment film having a liquid crystal alignment control ability is manufactured.
The coating film used in the present invention realizes highly efficient introduction of anisotropy into the coating film by utilizing the principle of molecular reorientation induced by self-organization based on side chain photoreaction and liquid crystallinity. . In the production method of the present invention, in the case of a structure having a photocrosslinkable group as a photoreactive group in the side chain type polymer, after forming a coating film on a substrate using the side chain type polymer, polarized ultraviolet light is applied. After irradiation and heating, a liquid crystal display element is formed.

By doing so, the liquid crystal display device provided by the present invention exhibits high reliability against external stress such as light and heat.
As described above, the substrate for a lateral electric field driving type liquid crystal display element manufactured by the method of the present invention or the lateral electric field driving type liquid crystal display element having the substrate has excellent reliability, and has a large screen and high definition. It can be suitably used for liquid crystal televisions.

  Hereinafter, the present invention will be described using examples, but the present invention is not limited to the examples.

  The abbreviations used in the examples are as follows.

(Methacrylic monomer)

(Bipyridine-based additive)

(Organic solvent)
THF: tetrahydrofuran NMP: N-methyl-2-pyrrolidone BC: butyl cellosolve

(Polymerization initiator)
The conditions for measuring the molecular weight of AIBN: 2,2'-azobisisobutyronitrile polymer are as follows.
Apparatus: Room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Kagaku
Column: Shodex columns (KD-803, KD-805)
Column temperature: 50 ° C

Eluent: N, N'-dimethylformamide (as an additive, lithium bromide hydrate (Li
(Br.H2O) 30 mmol / L, phosphoric acid / anhydrous crystals (o-phosphoric acid) 30 mmol / L
L, tetrahydrofuran (THF) is 10 ml / L)
Flow rate: 1.0 ml / min

Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: about 9,000,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (molecular weight: about 12,000, molecular weight manufactured by Polymer Laboratories) 000
, 1,000).

<Example 1>
M6CA (12.41 g, 35.0 mmol) was dissolved in THF (111.7 g), deaerated by a diaphragm pump, and AIBN (0.287 g, 1.8 mmol) was added, followed by deaeration again. Was. Thereafter, the mixture was reacted at 60 ° C. for 30 hours to obtain a methacrylate polymer solution. This polymer solution was dropped into diethyl ether (500 ml), and the obtained precipitate was filtered. The precipitate was washed with diethyl ether and dried in a vacuum oven at 40 ° C. under reduced pressure to obtain a methacrylate polymer powder (A). The number average molecular weight of this polymer was 11,000, and the weight average molecular weight was 26,000.

NMP (29.29 g) was added to the obtained methacrylate polymer powder (A) (6.0 g), and dissolved by stirring at room temperature for 5 hours. NMP (14.7 g) and BC (50.0 g) were added to this solution and stirred for 5 hours to obtain a liquid crystal aligning agent (A1).
Further, 0.03 g (5% by mass based on the solid content) of a bipyridine-based additive BPy was added to 10.0 g of the liquid crystal aligning agent (A1), and the mixture was stirred at room temperature for 3 hours to be dissolved. Agent (A2) was prepared.

  Further, 0.03 g (5% by mass based on the solid content) of a bipyridine-based additive BPyStyl was added to 10.0 g of the liquid crystal aligning agent (A1), and the mixture was stirred at room temperature for 3 hours to be dissolved. Agent (A3) was prepared.

  Further, 0.03 g (5% by mass based on the solid content) of a bipyridine-based additive BPyC2 was added to 10.0 g of the above liquid crystal aligning agent (A1), and the mixture was stirred at room temperature for 3 hours to be dissolved. Agent (A4) was prepared.

  Further, 0.03 g (5% by mass based on the solid content) of a bipyridine-based additive BPyC3 was added to 10.0 g of the above liquid crystal aligning agent (A1), and the mixture was stirred at room temperature for 3 hours to be dissolved. Agent (A5) was prepared.

<Example 2>
M6BA (15.32 g, 50.0 mmol) was dissolved in THF (141.6 g), degassed by a diaphragm pump, and AIBN (0.411 g, 2.5 mmol) was added, followed by degassing again. Was. Thereafter, the mixture was reacted at 60 ° C. for 30 hours to obtain a methacrylate polymer solution. This polymer solution was added dropwise to diethyl ether (1500 ml), and the obtained precipitate was filtered. The precipitate was washed with diethyl ether, and dried in an oven at 40 ° C. under reduced pressure to obtain a methacrylate polymer powder (B). The number average molecular weight of this polymer was 13,000, and the weight average molecular weight was 31,000.

NMP (29.29 g) was added to the obtained methacrylate polymer powder (B) (6.0 g), and dissolved by stirring at room temperature for 5 hours. NMP (147.5 g) and BC (50.0 g) were added to this solution and stirred for 5 hours to obtain a liquid crystal aligning agent (B1).

  Further, 0.03 g (5% by mass based on the solid content) of a bipyridine-based additive BPyStyl was added to 10.0 g of the above liquid crystal aligning agent (B1), and the mixture was stirred at room temperature for 3 hours to be dissolved. Agent (B2) was prepared.

<Example 3>
A liquid crystal cell was prepared using the liquid crystal aligning agent (A2) obtained in Example 1, and the alignment of the low molecular liquid crystal was confirmed. The irradiation amount of the polarized UV in the alignment treatment and the heating temperature after the irradiation of the polarized UV were varied, and the conditions for obtaining the optimal alignment were confirmed.

[Production of liquid crystal cell]
The substrate used was a glass substrate having a size of 30 mm × 40 mm and a thickness of 0.7 mm, on which a comb-shaped pixel electrode formed by patterning an ITO film was arranged. The pixel electrode has a comb-like shape formed by arranging a plurality of square-shaped electrode elements whose central portion is bent. The width in the lateral direction of each electrode element is 10 μm, and the interval between the electrode elements is 20 μm. Since the pixel electrode forming each pixel is configured by arranging a plurality of bent-shaped electrode elements at the center portion, the shape of each pixel is not rectangular but is similar to the electrode element at the center portion. Bends have a shape resembling a bold letter. Each pixel is vertically divided by a center bent portion, and has a first region above the bent portion and a second region below the bent portion. When the first region and the second region of each pixel are compared, the formation directions of the electrode elements of the pixel electrodes constituting the first region and the second region are different. That is, when the orientation direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode is formed so as to form an angle of + 15 ° (clockwise) in the first region of the pixel, and in the second region of the pixel. The electrode elements of the pixel electrode are formed so as to form an angle of -15 ° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal induced by the application of the voltage between the pixel electrode and the counter electrode in the substrate plane are mutually different. It is configured to be in the opposite direction. The liquid crystal aligning agent (A2) obtained in Example 1 was spin-coated on the prepared substrate with electrodes. Next, drying was performed for 90 seconds on a hot plate at 70 ° C. to form a liquid crystal alignment film having a thickness of 100 nm. Next, the coating film surface was irradiated with 313 nm ultraviolet rays at 3 to 13 mJ / cm 2 through a polarizing plate, and then heated on a hot plate at 140 to 170 ° C. for 10 minutes to obtain a substrate with a liquid crystal alignment film. Further, a coating film was similarly formed on a glass substrate having a columnar spacer having a height of 4 μm on which no electrode was formed as an opposing substrate, and was subjected to an alignment treatment. A sealant (XN-1500T manufactured by Kyoritsu Chemical) was printed on the liquid crystal alignment film of one of the substrates. Next, the other substrate was bonded so that the surfaces of the liquid crystal alignment films faced each other so that the alignment direction was 0 °, and then the sealant was thermally cured to prepare empty cells. A liquid crystal MLC-2041 (manufactured by Merck) is injected into the empty cell by a reduced pressure injection method, the injection port is sealed, and a liquid crystal cell having a configuration of an IPS (In-Planes Switching) mode liquid crystal display element is obtained. Obtained.

  The obtained liquid crystal cell was placed between crossed Nicol polarizing plates, and the orientation of the liquid crystal was confirmed. Further, an AC voltage of 8 Vpp was applied between the electrodes, and it was confirmed whether the liquid crystal in the pixel portion was driven. The following table shows the results of the liquid crystal alignment depending on the amount of polarized UV irradiation and the subsequent heating temperature. In addition, x indicates that the alignment defect such as flow alignment was confirmed after liquid crystal injection, and x indicates that the alignment was satisfactory without the alignment defect.

<Example 4>
In the same manner as in Example 3, a liquid crystal cell was prepared using the liquid crystal aligning agent (A3), and the alignment of the obtained liquid crystal cell was confirmed. Table 2 below shows the results of the liquid crystal orientation of the liquid crystal cell.

<Example 6>
In the same manner as in Example 3, a liquid crystal cell was prepared using the liquid crystal aligning agent (A4), and the alignment of the obtained liquid crystal cell was confirmed. Table 3 below shows the results of the liquid crystal orientation of the liquid crystal cell.

<Example 7>
In the same manner as in Example 3, a liquid crystal cell was prepared using the liquid crystal alignment agent (A5), and the alignment of the obtained liquid crystal cell was confirmed. Table 4 below shows the results of the liquid crystal orientation of the liquid crystal cell.

<Comparative Example 1>
In the same manner as in Example 3, a liquid crystal cell was prepared using the liquid crystal alignment agent (A1), and the orientation of the obtained liquid crystal cell was confirmed. Table 5 below shows the results of the liquid crystal orientation of the liquid crystal cell.

From the results in Tables 1 to 5, it was confirmed that the addition of the pyridine-based additive changes the heating temperature and the irradiation amount of polarized UV at which the optimal orientation can be obtained with respect to the comparative example. In particular, regarding the heating temperature, since there is a concern that the electrical characteristics of the liquid crystal display element may be deteriorated due to the influence of the residual solvent, etc., it is required to perform the firing at a temperature as high as possible. Being able to arbitrarily select the obtained heating conditions leads to broadening the range of material selection.
It is considered that the reason why the optimal irradiation amount and the heating temperature were changed is that the mesogen portion of the supramolecular liquid crystal was changed and the UV absorption band, the sensitivity and the reaction rate by the UV were changed.
[Evaluation as polymer film]

<Example 7>
Next, 0.06 g (10% by mass based on the solid content) of a bipyridine-based additive BPy was added to 10.0 g of the liquid crystal aligning agent (A1), and the mixture was stirred at room temperature for 3 hours to be dissolved. Composition (A6) was prepared.

  Further, 0.3 g (50% by mass based on the solid content) of a bipyridine-based additive BPy was added to 10.0 g of the liquid crystal aligning agent (A1), and the mixture was stirred at room temperature for 3 hours to be dissolved. A7) was prepared.

<Example 8>
The optically active composition (A6) obtained in Example 7 was applied on a 1.1 mm quartz substrate by spin coating so as to have a thickness of 100 nm, and dried on a hot plate at 70 ° C.

  The dichroism when the coating film was irradiated with 313 nm polarized UV from 0 J / cm2 to 30 J / cm2 was tracked. The dichroism ΔA was calculated by the following formula by measuring a polarized UV-vis absorption spectrum.

                      Dichroism {A = A / -A}

(A // indicates the absorbance in the direction parallel to the irradiated polarized UV, and A⊥ indicates the absorbance in the ⊥ direction relative to the irradiated polarized UV. The absorbance is the value of the absorbance at 313 nm.)

Dichroism when the optically active composition (A7) was used in the same manner was also calculated.
In addition, UV-3100 (made by Shimadzu Corporation) was used for the measurement of the polarized UV-vis absorption spectrum.

<Comparative Example 2>
The dichroism of the liquid crystal aligning agent (A1) was also calculated in the same manner as in Example 8. The dichroism obtained from Example 8 and Comparative Example 2 is shown in FIG.

<Example 9>
Next, to 10.0 g of the liquid crystal aligning agent (A1), 0.06 g (10% by mass based on the solid content) of a bipyridine-based additive BPyAz (B-3) was added, and the mixture was stirred at room temperature for 3 hours. And dissolved to prepare an optically active composition (A8).

<Example 10>
The optically active composition (A8) obtained in Example 9 was applied to a 1.1 mm quartz substrate by a spin coating method so as to have a thickness of 100 nm, and dried on a hot plate at 70 ° C.
The coating film was irradiated with 313 nm polarized UV from 0 mJ / cm 2 to 150 mJ / cm 2, and then heated on a hot plate at 150 ° C. (so-called orientation amplification treatment by self-assembly of polymer liquid crystal), followed by an In-plane order parameter. (Degree of in-plane orientation S) was tracked. In addition, the measurement of the degree of in-plane orientation S was calculated by the following equation by measuring a polarized UV-vis absorption spectrum.

              In-plane orientation degree S = (A / −− A⊥) / (Al + 2As)

  (Al represents the larger absorbance in the polarized UV absorption spectrum (A // and A⊥), and As represents the smaller absorbance in the polarized UV absorption spectrum.)

<Comparative Example 3>
The degree of in-plane alignment S when the liquid crystal alignment agent (A1) was used was calculated in the same manner.
FIG. 2 shows the degree of in-plane orientation S at each irradiation dose obtained from Example 10 and Comparative Example 3.
In the evaluations of Examples 7 and 8, it was confirmed that by adding a bipyridine-based additive, it was possible to change the irradiation amount of polarized UV exhibiting maximum dichroism and the magnitude of dichroism. .

In addition, in the evaluations of Examples 9 and 10, it was confirmed that the optimum irradiation region for increasing the degree of in-plane orientation was dramatically increased as compared with the case where no bipyridine-based additive was used.

  The reason why the optimum irradiation amount and heating temperature were changed in Examples 1 to 10 was that the mesogen structure of the supramolecular liquid crystal changed and the UV absorption band and the sensitivity and reaction rate by UV changed. Was thought to be.

Claims (8)

It contains the following components (A) and (B), and contains a photoreactive group in either or both of the side chain of the component (A) and the component (B), and the components (A) and (B) Forms a liquid crystalline supramolecule via a hydrogen bond with an optically active composition.
(A) a polymer having a side chain containing a carboxylic acid group structure, and (B) at least one compound selected from the compounds represented by the following formula (1) or (2):

[Where,
X represents a single bond or alkylene having 1 to 12 carbon atoms, ether, ester, azo, thioether, disulfide, tetrazine, disubstituted alkene, alkyne, or phenylene;
S represents ether, ester or phenylene,
Py each independently represents a structure selected from the following group. In the following structures, a dotted portion is a portion that bonds to X in the formula (1) and bonds to S in the formula (2). Part

].   The optically active composition according to claim 1, wherein the component (A) contains a carboxylic acid group and a photoreactive group in one side chain structure.   The optically active composition according to claim 1, wherein the component (B) is contained in an amount of 0.5% by weight to 70% by weight based on the weight of the polymer of the component (A). The component (A) according to any one of claims 1 to 3, wherein the component (A) is a polymer having one type of photosensitive side chain selected from the group consisting of the following formulas (3) and (4). Optically active composition of:

[Where,
A represents a single bond, -O-, -COO-, -CONH-, and a group selected from -NH-,
B represents a single bond, -O-, -COO-, -CONH-, -NH-, and a group selected from -CH = CH-COO-,
Ar ₁ and Ar ₂ each independently represent a phenyl group or a naphthyl group;
l and m are each independently an integer from 0 to 12]. The optically active composition according to any one of claims 1 to 4, wherein the component (B) is at least one compound selected from the following.

[Where,
n represents an integer of 1 to 3,
l represents an integer of 2 to 6, and m represents an integer of 1 to 4.   A liquid crystal aligning agent, comprising the optically active composition according to claim 1.   A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 6. A liquid crystal display device comprising the liquid crystal alignment film according to claim 7.

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