JP7140336B2 - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, a liquid crystal display element using the same, and a polymer film suitable for manufacturing an optical element in which molecular orientation is controlled such as a retardation film and a polarization diffraction element. .

Liquid crystal display elements are known as lightweight, thin, and low power consumption display devices, and have made remarkable progress in recent years, such as being used for large-sized televisions. A 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 element, 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, is formed on the surfaces of the substrates that sandwich the liquid crystal and is in contact with the liquid crystal, and plays the role of orienting the liquid crystal in a certain direction between the substrates. In addition to the role of aligning the liquid crystal in a certain direction, such as a direction parallel to the substrate, the liquid crystal alignment film is sometimes required to play the role of controlling the pretilt angle of the liquid crystal. The ability to control the alignment of the liquid crystal in such a liquid crystal alignment film (hereinafter referred to as alignment controllability) is imparted by subjecting the organic film constituting the liquid crystal alignment film to alignment treatment.

A rubbing method is conventionally known as an alignment treatment method for a liquid crystal alignment film for imparting alignment controllability. The rubbing method involves rubbing the surface of an organic film such as polyvinyl alcohol, polyamide, or polyimide on a substrate with a cloth such as cotton, nylon, or polyester in a certain direction, and This is a method of orienting liquid crystals. Since this rubbing method can easily realize a relatively stable alignment state of the liquid crystal, it has been used in the manufacturing process of conventional liquid crystal display elements. As the organic film used for the liquid crystal alignment film, a polyimide-based organic film has been mainly selected because of its excellent reliability such as heat resistance and electrical properties.

However, the rubbing method of rubbing the surface of the 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 evenly rubbed with a cloth due to the recent increase in definition of the liquid crystal display element and the unevenness caused by the electrodes on the corresponding substrate and the switching active element for driving the liquid crystal. In some cases, alignment of the liquid crystal could not be achieved.

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

There are various photo-alignment methods, but 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 orientation methods are the “photodegradation type”, which causes anisotropic decomposition of the molecular structure by irradiating polarized ultraviolet rays, and the use of polyvinyl cinnamate, which is irradiated with polarized ultraviolet rays and oriented on two sides parallel to the polarized light. A "dimerization type" that causes a dimerization reaction (crosslinking reaction) at the double bond portion of the chain (see, for example, Patent Document 1.), When using a side chain type polymer having azobenzene in the side chain , By irradiating polarized ultraviolet rays, an isomerization reaction is caused in the azobenzene moiety of the side chain parallel to the polarized light, and the liquid crystal is oriented in the direction perpendicular to the polarization direction "isomerization type" (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 type polymer capable of exhibiting liquid crystallinity has been studied. In this method, a film having a photosensitive side-chain type polymer capable of exhibiting liquid crystallinity is subjected to an alignment treatment by irradiating polarized light, and then the side-chain type polymer film is heated. It is to obtain a given coating film. At this time, the slight anisotropy caused by polarized light irradiation becomes a driving force, and the liquid crystalline side-chain polymer itself is efficiently reoriented by self-organization. As a result, highly efficient alignment treatment is realized as a liquid crystal alignment film, and a liquid crystal alignment film imparted with high alignment controllability can be obtained (see Patent Document 2, for example).

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 orientation films but also as various optical elements such as retardation films. 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 UV irradiation for highly efficient introduction of anisotropy into the liquid crystal alignment film used in the orientation amplification method is the amount of polarized UV irradiation that optimizes the amount of photoreaction of the photosensitive groups in the coating film. corresponds to As a result of irradiating the liquid crystal alignment film used in the alignment amplification method with polarized ultraviolet rays, if the number of photoreactive side chain photosensitive groups is small, a sufficient amount of photoreaction cannot be obtained. In that case, even if it heats after that, sufficient self-organization will not progress. On the other hand, if the photoreactive side chain has an excess amount of photosensitive groups, the obtained film becomes rigid, which may hinder the progress of self-organization by subsequent heating.

At present, among the liquid crystal alignment films used in the alignment amplification method, there are some that have a narrow range of the above-mentioned optimum polarized ultraviolet irradiation amount, probably because the sensitivity of the photoreactive group in the polymer used is high. be. As a result, a decrease in manufacturing efficiency of the liquid crystal display element has become a problem.

Furthermore, if the firing temperature of the liquid crystal alignment film is low, the reliability of the liquid crystal display element may decrease due to the influence of the residual solvent. Since it cannot be fired at a temperature higher than the temperature at which liquid crystals appear, the firing temperature is generally low, which is one of the factors that reduce reliability, such as residual solvents.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a liquid crystal alignment film with a wide process margin, which is highly efficient and has alignment controllability, and which can be adjusted to the optimum amount of polarized ultraviolet irradiation and the optimum baking temperature.

The inventors of the present invention have made intensive studies to achieve the above objects, and as a result, have found the following invention.

<1> Contains the following components (A) and (B), contains a photoreactive group in either or both of the side chain of the component (A) and the component (B), and contains the component (A) and ( An optically active composition characterized by forming liquid crystalline supramolecules through hydrogen bonding with component B).
(A) a polymer having a side chain containing a carboxylic acid group structure, and (B) at least one aromatic heterocyclic compound represented by the following formula (1) or (2), pyrazine and naphthyridine Compound:

[In the formula,
X represents a single bond or an alkylene, ether, ester, azo, thioether, disulfide, tetrazine, disubstituted alkene, alkyne, or phenylene having 1 to 12 carbon atoms;
S represents ether, ester or phenylene,
Py each independently represents a structure selected from the following group, and in the structure below, the portion with a dot is the portion that binds to X in formula (1), and binds to S in 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). It's 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) It is preferably a polymer having side chains containing a group structure.

[In the formula,
A represents a group selected from a single bond, -O-, -COO-, -CONH-, and -NH-,
B represents a group selected from a single bond, -O-, -COO-, -CONH-, -NH-, and -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 <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］。

[In the formula,
n represents an integer from 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 of <7>.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided an optically active composition which is endowed with high-efficiency alignment controllability and has a wide range of optimum polarized ultraviolet irradiation dose, or which can suitably select the liquid crystal manifestation temperature of polymer liquid crystals. It is possible to provide a liquid crystal aligning agent containing a substance, a liquid crystal aligning film obtained from the liquid crystal aligning agent, a substrate having the liquid crystal aligning film, and a lateral electric field drive type liquid crystal display element having the substrate. Furthermore, by using the optically active composition, it is possible to provide a polymer film having a wide process margin (polarized ultraviolet irradiation amount and baking temperature) in the production of optical elements such as a retardation film.

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

Hereinafter, embodiments of the present invention will be described in detail.
<Optical active composition>
The optically active composition of the present invention contains the following components (A) and (B), one or both of (A) and (B) contains a photoreactive group, and (A) The component and the component (B) are characterized by forming liquid crystalline supramolecules through hydrogen bonding.
(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):

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

］。

].

Although it is not clear why the composition that satisfies the above constituent requirements has the effect of solving the problems of the present invention, it is generally considered as follows.

It is said that a polymer having a side chain containing a carboxylic acid group structure, which is the component (A) in the present invention, exhibits supramolecular liquid crystals due to hydrogen bonding between carboxylic acids. In such a supramolecular liquid crystal, the structure of the aromatic ring-carboxylic acid-carboxylic acid-aromatic ring forming the hydrogen bond has a mesogenic structure as shown below. It is considered that most of the absorption bands and the like are determined by this mesogenic site.

At this time, if the aromatic heterocyclic structure, which is the component (B) of the present invention, is present, part of the carboxylic acid forms a mesogenic structure through hydrogen bonding (or interaction such as ionic bonding) with the heterocyclic ring, resulting in liquid crystal to express their sexuality. As a result, the temperature range exhibiting liquid crystallinity, the ultraviolet absorption band, and the like change. In the present invention, by freely selecting a combination of these, it is possible to adjust the temperature range in which the liquid crystal is developed, the sensitivity to ultraviolet rays, and the like within an arbitrary range. Note that these are theories and do not limit the present invention.

<<(A) Component>>
Component (A) is a polymer having a side chain containing a carboxylic acid group structure. At this time, one side chain structure may contain a carboxylic acid group and a photoreactive group, or another side chain containing a photoreactive group may be present in the polymer. From the viewpoint of reaction efficiency, it is preferable to contain a carboxylic acid group and a photoreactive group in one side chain structure.

When one side chain structure contains a carboxylic acid group and a photoreactive group, 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-, among which -O- , -COO- are 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-, Of these, -O- and -COO- are preferred 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,
Integers from 2 to 8 are preferred.

Specific examples of the side chain structures represented by formulas (3) and (4) are shown below, but are not limited thereto.

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

<<Polymer manufacturing method>>
The polymer of component (A) can be obtained by a polymerization reaction of the above-mentioned specific side chain-containing monomers. It can also be obtained by copolymerizing 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 within a range that does not impair the ability to develop liquid crystallinity.
Other monomers include, for example, industrially available radical polymerizable monomers.

Specific examples of other monomers include unsaturated carboxylic acids, acrylic acid ester compounds, methacrylic acid ester compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds and vinyl compounds.

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

Examples of acrylic acid ester compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl acrylate, anthryl methyl acrylate, phenyl acrylate, 2,2,2-trifluoroethyl acrylate, tert-butyl acrylates, 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, 8-ethyl-8-tricyclodecyl acrylate and the like.

Examples of methacrylate compounds include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 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, 8-ethyl-8-tricyclodecyl methacrylate and the like. (Meth)acrylate compounds with cyclic ether groups 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 vinyl compounds include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.

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

Maleimide compounds include, for example, maleimide, N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, and the like.

The method for producing the component (A) polymer is not particularly limited, and a general industrial method 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 side chain monomer. Among these, radical polymerization is particularly preferred from the viewpoint of ease of reaction control.

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

A radical thermal polymerization initiator is a compound that generates radicals when heated to a decomposition temperature or higher. Examples of such radical thermal polymerization initiators include ketone peroxides (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), diacyl peroxides (acetyl peroxide, benzoyl peroxide, etc.), hydroperoxides (peroxide hydrogen, tert-butyl hydroxide, 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-ethylcyclohexanoic acid-tert-amyl ester, etc.), persulfates (potassium persulfate, sodium persulfate, ammonium persulfate, etc.), azo compounds (azobisisobutyronitrile, 2,2'-di(2-hydroxyethyl)azobisisobutyronitrile, etc.). Such radical thermal polymerization initiators can be used singly or in combination of two or more.

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 radical photopolymerization initiators include benzophenone, Michler's ketone, 4,4′-bis(diethylamino)benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy -2-methylpropiophenone, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexylphenyl ketone, 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-dimethylaminobenzoate, 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- [p-N,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)benzthiazole, 2-mercaptobenzothiazole, 3,3′-carbonylbis(7-diethylaminocoumarin), 2-(o-chlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole, 2 , 2'-bi Su(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-cyclopentadiene-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, 2-(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 emulsion polymerization method, suspension polymerization method, dispersion polymerization method, precipitation polymerization method, bulk polymerization method, solution polymerization method and the like can be used.

The organic solvent used for the polymerization reaction is not particularly limited as long as it dissolves the produced polymer. 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, 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, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, acetic acid Ethyl, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionate acid, 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 in combination. Furthermore, even a solvent that does not dissolve the generated polymer may be mixed with the above-described organic solvent and used as long as the generated polymer does not precipitate.

In addition, since oxygen in an organic solvent inhibits the polymerization reaction in radical polymerization, it is preferable to use an organic solvent that has been degassed to the extent possible.
The polymerization temperature for radical polymerization may be any temperature from 30°C to 150°C, preferably from 50°C to 100°C. In addition, the reaction can be carried out at any concentration, but if the concentration is too low, it becomes difficult to obtain a high-molecular-weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high, making uniform stirring difficult. Therefore, the monomer concentration is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 30% by mass. The initial stage of the reaction can be carried out at a high concentration, and then the organic solvent can be added.
In the radical polymerization reaction described above, if the ratio of the radical polymerization initiator to the monomer is large, the molecular weight of the polymer obtained will be small, and if it is small, the molecular weight of the polymer obtained will be large. It is preferably 0.1 mol % to 10 mol % with respect to the monomer to be polymerized. Further, various monomer components, solvents, initiators, etc. can be added during polymerization.

[Recovery of polymer]
In the case of recovering the produced polymer from the reaction solution of the polymer obtained by the above reaction, the polymer may be precipitated by putting the reaction solution into a poor solvent. Poor solvents 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, and water. The polymer precipitated by putting it into a poor solvent can be filtered and recovered, and then dried at room temperature or under heat under normal pressure or reduced pressure. In addition, the impurities in the polymer can be reduced by redissolving the precipitated and recovered polymer in an organic solvent and repeating the operation of reprecipitating and recovering 2 to 10 times. Examples of the poor solvent in this case include alcohols, ketones, hydrocarbons, and the like, and it is preferable to use three or more poor solvents selected from these, because the purification efficiency is further improved.

The molecular weight of the polymer of component (A) of the present invention was measured by GPC (Gel Permeation Chromatography) in consideration of the strength of the resulting coating film, the workability during coating film formation, and the 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 compounds represented by the following formula (1) or (2) as 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; It preferably represents an ester, azo, disubstituted alkene or alkyne. Here, "disubstituted alkene" refers to a disubstituted alkene having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, and the substituent of this 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 formulas (1) and (2) above, each Py independently represents a structure selected from the following group. In the structure below, the portion marked with a dot is the portion that bonds to X in Formula (1) and the portion that bonds to S in Formula (2). Preferred Py are 4-pyridyl, 4-pyridylphenyl.

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

[In the formula,
n represents an integer from 1 to 3,
l represents an integer from 2 to 6, and m represents an integer from 1 to 4].

From the viewpoint of exhibiting liquid crystallinity, B1 to B9, B16 and B18 are preferable, and B1 to B5 are more preferable.

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

Similar effects can also be obtained by using the following compounds as the component (B).

<Adjustment of optically active composition>
The optically active composition used in the present invention is preferably prepared as a coating liquid so as to be suitable for forming a coating film. That is, it is preferable to prepare a solution in which the A component, the B component, and various additives to be added as necessary, which will be described later, are dissolved in an organic solvent. At that time, the content of the total component (hereinafter also referred to as the resin component) of the A component, the B component, and various additives added as necessary is preferably 1% by mass to 20% by mass, more preferably 3 % to 15% by weight, particularly preferably 3% to 10% by weight.

<Organic solvent>
The organic solvent used in the optically active composition of the present invention is not particularly limited as long as it 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, dimethylsulfone, hexamethylsulfoxide, 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 mono acetate, 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 and the like. These may be used alone or in combination.

The polymer contained in the optically active composition of the present invention may be a polymer having a side chain containing the above-described carboxylic acid group structure, provided that the liquid crystal display ability and photosensitive performance are not impaired. Other polymers other than these 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.

Such other polymers include, for example, poly(meth)acrylates, polyamic acids, polyimides, and the like, which are not photosensitive side-chain type polymers capable of exhibiting liquid crystallinity.

The optically active composition of the present invention may contain components other than the above components (A) and (B). Examples thereof include solvents and compounds that improve film thickness uniformity and surface smoothness when a solution of an optically active composition is applied, and compounds that improve adhesion between a coating film and a substrate. but not limited to this.
Specific examples of the solvent (poor solvent) that improve the uniformity of film thickness and surface smoothness include the following.

For example, isopropyl alcohol, methoxymethylpentanol, 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, 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, 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, n-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, pyruvate ethyl acetate, methyl 3-methoxypropionate, 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 can be used.

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

Compounds that improve film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, nonionic surfactants, and the like.

More specifically, for example, Ftop (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. be done. The proportion of these surfactants used is preferably 0.01 parts by mass to 2 parts by mass, more preferably 0.01 parts by mass to 1 part by mass, with respect to 100 parts by mass of the resin component contained in the polymer composition. part by mass.

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-triethoxysilyl- 1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane silane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, and the like.

Furthermore, in addition to improving the adhesion between the substrate and the coating film, the following additives such as phenoplasts and epoxy group-containing compounds are added for the purpose of preventing deterioration of electrical properties due to backlight when composing a liquid crystal display element. 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, 1, 6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N', N',-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N',-tetraglycidyl-4,4'-diaminodiphenylmethane etc. are exemplified.

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

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

Photosensitizers include aromatic nitro compounds, coumarins (7-diethylamino-4-methylcoumarin, 7-hydroxy 4-methylcoumarin), ketocoumarins, carbonylbiscoumarins, aromatic 2-hydroxyketones, and amino-substituted , aromatic 2-hydroxyketones (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-methylbenzothiazoline, 2-(β-naphthoylmethylene)-3-methyl-β-naphthothiazoline, 2-(4-biphenoylmethylene)-3-methyl-β-naphthothiazoline, 2-(p-fluoro benzoylmethylene)-3-methyl-β-naphthothiazoline), oxazoline (2-benzoylmethylene-3-methyl-β-naphthoxazoline, 2-(β-naphthoylmethylene)-3-methylbenzoxazoline, 2-(α -naphthoylmethylene)-3-methylbenzoxazoline, 2-(4-biphenoylmethylene)-3-methylbenzoxazoline, 2-(β-naphthoylmethylene)-3-methyl-β-naphthoxazoline, 2-( 4-biphenoylmethylene)-3-methyl-β-naphthoxazoline, 2-(p-fluorobenzoylmethylene)-3-methyl-β-naphthoxazoline), 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-anthracenecarboxylic acid), benzopyran, azoindolizine, merocumarin, etc. be.

Preferred are aromatic 2-hydroxyketones (benzophenones), coumarins, ketocoumarins, carbonylbiscoumarins, acetophenones, anthraquinones, xanthones, thioxanthones, and acetophenone ketals.

In addition to those mentioned above, the optically active composition of the present invention may contain a dielectric or a conductive compound for the purpose of changing the electrical properties of the coating film, such as dielectric constant and conductivity, as long as the effects of the present invention are not impaired. A cross-linking compound may be added for the purpose of increasing the hardness and denseness of the coating film.

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

Industrially, screen printing, offset printing, flexographic printing, ink jet method, or the like is generally used as the coating method. Other coating methods include a dip method, a roll coater method, a slit coater method, a spinner method (rotational coating method), a spray method, and the like, and these may be used depending on the purpose.

<<Manufacturing of liquid crystal display element>>
<Step [I]>
The production of a liquid crystal display element using the liquid crystal aligning agent containing the optically active composition of the present invention is represented by the following steps [I] to [IV]. First, process [I] is a process of apply|coating the liquid crystal aligning agent of this invention on the board|substrate which has a conductive film. After coating, the solvent is evaporated at 50 to 200° C., preferably 50 to 150° C. by heating means such as a hot plate, thermal circulation oven or IR (infrared) oven to obtain a coating film. The drying temperature at this time is preferably lower than the liquid crystal phase development temperature of the side chain type polymer.

The thickness of the coating film is preferably 5 nm to 300 nm, more preferably 10 nm to 150 nm, because if it 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 decrease. is.
It is also possible to provide a step of cooling the substrate having the coating film formed thereon to room temperature after the step [I] and before the subsequent step [II].

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

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

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

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

In addition, the liquid crystal manifestation temperature is the glass transition temperature (Tg) or higher at which the side chain type polymer or the coating film surface undergoes a phase transition from the solid phase to the liquid crystal phase, and from the liquid crystal phase to the isotropic phase (isotropic phase). The 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 step [I].

With the steps described above, the production method of the present invention can introduce anisotropy into the coating film with high efficiency. And 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 [III] is arranged opposite to each other so that both liquid crystal alignment films face each other through the liquid crystal, and a liquid crystal cell is produced by a known method. Then, it 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 described above are prepared, spacers are dispersed on the liquid crystal alignment film of one of the substrates, and the liquid crystal alignment film surface faces inside. Examples include a method of bonding the other substrate and injecting liquid crystal under reduced pressure and sealing, or a method of bonding the substrates together and sealing after dropping liquid crystal on the surface of the liquid crystal alignment film on which spacers are scattered. can do. At this time, it is preferable to use a substrate having an electrode having a comb-like structure for driving a horizontal electric field as one of the substrates. 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 holding the liquid crystal layer, that is, the thickness of the liquid crystal layer.

In the method for producing a coated substrate of the present invention, a polymer composition is applied onto a substrate to form a coating film, and then polarized ultraviolet rays are irradiated. Next, by heating, highly efficient introduction of anisotropy into the side chain type polymer film is realized, and a substrate with a liquid crystal alignment film having liquid crystal alignment controllability is manufactured.
In the coating film used in the present invention, the principle of molecular reorientation induced by photoreaction of side chains and self-organization based on liquid crystallinity is used to efficiently introduce anisotropy into the coating film. . 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 the substrate using the side chain type polymer, polarized ultraviolet light is applied. After irradiation and then heating, a liquid crystal display element is produced.

By doing so, the liquid crystal display element 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-driven liquid crystal display element manufactured by the method of the present invention or the lateral electric field-driven liquid crystal display element having the substrate is excellent in reliability, and has a large screen and high definition. It can be suitably used for liquid crystal televisions and the like.

EXAMPLES The present invention will be described below 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)
AIBN: The conditions for measuring the molecular weight of the 2,2'-azobisisobutyronitrile polymer are as follows.
Apparatus: Room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Scientific Co., Ltd.
Column: Shodex column (KD-803, KD-805)
Column temperature: 50°C

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

Standard samples for creating a calibration curve: TSK standard polyethylene oxide manufactured by Tosoh Corporation (molecular weight of about 9000,000, 150,000, 100,000, 30,000), and polyethylene glycol manufactured by Polymer Laboratory (molecular weight of about 12,000, 4 ,000
, 1,000).

<Example 1>
M6CA (12.41 g, 35.0 mmol) was dissolved in THF (111.7 g) and degassed with a diaphragm pump, then AIBN (0.287 g, 1.8 mmol) was added and degassed again. rice field. After that, 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 (500 ml) and the resulting precipitate was filtered. The precipitate was washed with diethyl ether and dried under reduced pressure in an oven at 40° C. to obtain methacrylate polymer powder (A). This polymer had a number average molecular weight of 11,000 and a weight average molecular weight of 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 relative to the solid content) of bipyridine-based additive BPy is added to 10.0 g of the liquid crystal aligning agent (A1), and stirred at room temperature for 3 hours to dissolve the liquid crystal aligning agent. Agent (A2) was prepared.

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

Further, 0.03 g (5% by mass relative to the solid content) of bipyridine-based additive BPyC2 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 dissolve the liquid crystal aligning agent. Agent (A4) was prepared.

Further, 0.03 g of bipyridine-based additive BPyC3 (5% by mass relative to the solid content) 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 dissolve the liquid crystal aligning agent. Agent (A5) was prepared.

<Example 2>
M6BA (15.32 g, 50.0 mmol) was dissolved in THF (141.6 g) and degassed with a diaphragm pump, then AIBN (0.411 g, 2.5 mmol) was added and degassed again. rice field. After that, 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 resulting precipitate was filtered. The precipitate was washed with diethyl ether and dried under reduced pressure in an oven at 40° C. to obtain methacrylate polymer powder (B). This polymer had a number average molecular weight of 13,000 and a weight average molecular weight of 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 (14.7.5 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 relative to the solid content) of the bipyridine-based additive BPyStyl was added to 10.0 g of the liquid crystal aligning agent (B1), and stirred at room temperature for 3 hours to dissolve the liquid crystal aligning agent. 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-weight liquid crystal was confirmed. The irradiation amount of polarized UV in the alignment treatment and the heating temperature after the irradiation of polarized UV were changed, and the conditions under which the optimum alignment was obtained were confirmed.

[Production of liquid crystal cell]
The substrate used was a glass substrate with a size of 30 mm×40 mm and a thickness of 0.7 mm, on which comb-shaped pixel electrodes formed by patterning an ITO film were arranged. The pixel electrode has a comb-like shape formed by arranging a plurality of dogleg-shaped electrode elements with a bent central portion. The width of each electrode element in the lateral direction is 10 μm, and the interval between electrode elements is 20 μm. Since the pixel electrode that forms each pixel is configured by arranging a plurality of bent dogleg-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but in the central portion like the electrode elements. It has a curved shape resembling a bold character. Each pixel is vertically divided by the curved portion in the center, and has a first region above the curved portion and a second region below the curved portion. Comparing the first region and the second region of each pixel, the formation direction of the electrode elements of the pixel electrodes constituting them is different. That is, when the alignment processing direction of the liquid crystal alignment film, which will be described later, is used as a reference, the electrode elements of the pixel electrode are 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 at an angle of -15° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotational movement (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode in the plane of the substrate 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. Then, it was dried on a hot plate at 70° C. for 90 seconds to form a liquid crystal alignment film with a thickness of 100 nm. Next, the coated 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. A glass substrate having columnar spacers with a height of 4 μm on which electrodes are not formed as a counter substrate was similarly formed with a coating film and subjected to orientation treatment. A sealant (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was printed on the liquid crystal alignment film of one substrate. Then, the other substrate was attached so that the liquid crystal alignment film surfaces faced each other and the alignment direction was 0°, and then the sealant was thermally cured to prepare an empty cell. Liquid crystal MLC-2041 (manufactured by Merck Co., Ltd.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell having an IPS (In-Planes Switching) mode liquid crystal display element configuration. Obtained.

The resulting liquid crystal cell was placed between crossed Nicol polarizing plates to confirm the orientation of the liquid crystal. An AC voltage of 8 Vpp was applied between the electrodes to confirm whether or not the liquid crystal in the pixel portion was driven. The following table shows the results of liquid crystal orientation depending on the amount of polarized UV irradiation and subsequent heating temperature. It should be noted that X indicates that an alignment defect such as flow alignment was confirmed after liquid crystal injection, and ◯ indicates a sample that has no alignment defect and good liquid crystal alignment was confirmed.

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

<Example 6>
A liquid crystal cell was prepared using the liquid crystal aligning agent (A4) in the same manner as in Example 3, and the orientation 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>
A liquid crystal cell was prepared using the liquid crystal aligning agent (A5) in the same manner as in Example 3, and the orientation of the obtained liquid crystal cell was confirmed. Table 4 below shows the results of the liquid crystal orientation properties of the liquid crystal cell.

<Comparative Example 1>
A liquid crystal cell was prepared using the liquid crystal aligning agent (A1) in the same manner as in Example 3, 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 changed the heating temperature and the amount of polarized UV irradiation at which the optimum orientation was obtained compared to the comparative example. In particular, regarding the heating temperature, there is concern that the electrical properties of liquid crystal display elements may deteriorate due to the effects of residual solvents, etc., so it is necessary to bake at as high a temperature as possible. The ability to arbitrarily select the heating conditions to be obtained leads to a wider range of material selection.
The reason why the optimum irradiation dose and heating temperature changed is considered to be that the mesogenic portion of the supramolecular liquid crystal changes, resulting in changes in the UV absorption band, UV sensitivity, and reaction rate.
[Evaluation as a polymer film]

<Example 7>
Next, to 10.0 g of the liquid crystal aligning agent (A1), 0.06 g of bipyridine-based additive BPy (10% by mass relative to the solid content) was added, stirred at room temperature for 3 hours to dissolve, and optically active. A composition (A6) was prepared.

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

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

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

Dichroism △A=A//-A⊥

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

The dichroism when using the optically active composition (A7) was also calculated in a similar manner.
UV-3100 (manufactured by Shimadzu Corporation) was used to measure 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 relative to the solid content) of the bipyridine-based additive BPyAz (B-3 above) was added and stirred at room temperature for 3 hours. 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 spin coating to a film thickness of 100 nm, and dried on a hot plate at 70°C.
After irradiating this coating film with polarized UV of 313 nm from 0 mJ / cm to 150 mJ / cm 2, heating with a hot plate at 150 ° C. (so-called orientation amplification treatment by self-assembly of polymer liquid crystal) In-plane order parameters (In-plane orientation degree S) was tracked. The in-plane orientation degree S was calculated by the following formula after measuring the polarized UV-vis absorption spectrum.

In-plane orientation 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 in-plane orientation degree S in the case of using the liquid crystal aligning agent (A1) was also calculated by the same method.
FIG. 2 shows the in-plane orientation degree S at each dose obtained from Example 10 and Comparative Example 3. As shown in FIG.
In the evaluation of Examples 7 and 8, it was confirmed that by adding a bipyridine-based additive, it was possible to change the amount of polarized UV radiation that exhibits the maximum dichroism and the magnitude of the dichroism. .

Further, in the evaluation of Examples 9 and 10, it was confirmed that the optimum irradiation region for increasing the degree of in-plane orientation was dramatically expanded as compared with the case where there was no bipyridine-based additive.

The reason why the optimum irradiation dose and heating temperature changed in Examples 1 to 10 is that the UV absorption band and UV sensitivity and reaction rate changed due to changes in the mesogenic structure of the supramolecular liquid crystal. It was thought that

Claims (5)

Containing the following components (A) and (B), containing 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) A liquid crystal aligning agent, comprising an optically active composition characterized by forming liquid crystalline supramolecules through hydrogen bonding.
(A) a polymer having a side chain containing a carboxylic acid group structure, the polymer having any one photosensitive side chain selected from the group consisting of the following formulas (3) and (4); (B) at least one compound selected from compounds represented by the following formula (1) or (2) :

[In the formula,
X represents a single bond or an alkylene, ether, ester, azo, thioether, disulfide, tetrazine, disubstituted alkene, alkyne, or phenylene having 1 to 12 carbon atoms;
S represents ether, ester or phenylene,
Py each independently represents a structure selected from the following group, and in the structure below, the portion with a dot is the portion that binds to X in formula (1), and binds to S in formula (2) is a part

],

[In the formula,
A represents a group selected from a single bond, -O-, -COO-, -CONH-, and -NH-,
B represents a group selected from a single bond, -O-, -COO-, -CONH-, -NH-, and -CH=CH-COO-,
Ar ₁ and Ar ₂ each independently represent a phenyl group or a naphthyl group;
l is an integer from 0 to 12 and m is 0 ]. The liquid crystal aligning agent according to claim 1, wherein the component (A) contains a carboxylic acid group and a photoreactive group in one side chain structure. 3. The liquid crystal aligning agent 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). A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 3. A liquid crystal display device comprising the liquid crystal alignment film according to claim 4 .

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