JP4694182B2 - Liquid crystal pretilt angle imparting agent for photo-alignment film, composition for photo-alignment film, and method for producing photo-alignment film - Google Patents

Description

  The present invention relates to a liquid crystal pretilt angle imparting agent for a liquid crystal alignment film, and more specifically, a liquid crystal alignment film (hereinafter referred to as a photoalignment film) that can control the tilt angle of liquid crystal to an arbitrary angle without rubbing by irradiating light. The present invention relates to a liquid crystal pretilt angle imparting agent, a composition for photoalignment film containing the liquid crystal pretilt angle imparting agent for photoalignment film, and a method for producing a photoalignment film on which the composition for photoalignment film is applied.

  In the liquid crystal display element, the state of the molecular arrangement of the liquid crystal is changed by the action of an electric field or the like, and the change in the optical characteristics accompanying this is used for display. In many cases, the liquid crystal is used in a state of being sandwiched between two substrates. Here, in order to align the liquid crystal molecules in a specific direction, a film having an alignment function (hereinafter referred to as an alignment film) is arranged inside the substrate. Abbreviated). At this time, in order to suppress a decrease in contrast, a pretilt is imparted to the liquid crystal molecules to prevent the occurrence of tilting (disclination), and an alignment technique that can impart an arbitrary pretilt angle to the liquid crystal molecules. Is required. Since the pretilt depends on the type of liquid crystal to be used and the required pretilt angle differs depending on the display mode of the liquid crystal display element, a method capable of more easily adjusting the pretilt is required.

  Usually, the alignment treatment is performed by a method called rubbing, in which a polymer film such as polyimide is provided on a substrate such as glass and is rubbed with a cloth or the like in one direction. As a result, the liquid crystal molecules in contact with the substrate are arranged so that their long axes (directors) are parallel to the rubbing direction. However, according to the rubbing method, alignment defects may occur due to scratches or dust generated on the surface of the alignment film, which may adversely affect the display characteristics of the obtained liquid crystal display element.

On the other hand, a liquid crystal alignment control technique that does not perform rubbing has recently attracted attention. In particular, a photo-alignment method for obtaining a film having liquid crystal alignment properties by irradiating polarized light onto a coating film provided on a substrate is simple and actively researched.
This photo-alignment method is a photo-alignment group that develops a liquid crystal alignment function in organic molecules, for example, by photodimerization of cinnamoyl group, coumarin group, chalcone group, benzophenone group, etc., by photoisomerization of azo group, The thing by the photodecomposition of polyimide resin etc. has been reported, and also fixing the orientation group is examined for the purpose of stabilizing the orientation state of these photo-orientation groups.

  For example, a composition for a photo-alignment film containing a dichroic dye having two or more polymerizable groups in one molecule is applied on a substrate and irradiated with polarized light to give a liquid crystal alignment function, followed by heating or A method of obtaining a photo-alignment film by polymerizing a polymerizable group by irradiating light is known (for example, see Patent Document 1). Since the dichroic dye has a low molecular weight, it can be easily aligned, and further has two or more polymerizable groups and can be easily polymerized, so that an alignment film having excellent long-term stability can be obtained. However, this method can provide a photo-alignment film having excellent long-term stability against light and heat, but it does not specify any pretilt angle control.

A photo-alignment film is also known in which circularly polarized light is incident on a polyvinyl alcohol thin film containing an azo dye such as methyl orange, and the azo dye is tilted (see, for example, Patent Document 2). The alignment film can change the pretilt angle according to the incident angle of polarized light. However, in order to obtain a desired pretilt angle, it is necessary to adjust the incident angle of the irradiated circularly polarized light, which is not easy.
JP 2002-250924 A Japanese Patent Laid-Open No. 10-246889

  An object of the present invention is to provide a photo-alignment film that can easily control a desired pretilt angle, particularly a pretilt angle within a range of 20 ° from the substrate surface.

  The present inventors use an azo compound having a group having affinity for a substrate such as a hydroxy group, a carboxyl group, a sulfo group, a nitro group, an amino group, or a hydroxy group and a long-chain alkyl group for a photo-alignment film. The said subject was solved by adding to a composition. The liquid crystal pretilt angle imparting agent for a photo-alignment film of the present invention can change the pretilt angle of the liquid crystal only by changing the addition amount thereof.

  That is, the present invention provides a liquid crystal pretilt angle imparting agent for a photo-alignment film represented by the general formula (1).

（式中、Ｒ^１は、（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、（メタ）アクリルアミド基、ビニル基、ビニルオキシ基、マレイミド基、カルボキシル基、スルホ基、ニトロ基、アミノ基、又はヒドロキシ基を表す（但し、カルボキシル基及びスルホ基は、アルカリ金属と塩を形成していてもよい）。
Ｘ^１は、−（Ａ^１−Ｂ^１）_ｍ1−で表される連結基を表し、Ｘ^２は−（Ａ^２−Ｂ^２）_ｎ1−で表される連結基を表す。ここで、Ａ^１及びＡ^２は各々独立して単結合、又は二価の炭化水素基を表し、Ｂ^１及びＢ^２は各々独立して単結合、−Ｏ−、−ＣＯ−Ｏ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＮＨＣＯ−Ｏ−、又は−ＯＣＯＮＨ−を表す。ｍ１及びｎ１は各々独立して０〜４の整数を表す。但し、ｍ１又はｎ１が２以上のとき、複数あるＡ^１、Ｂ^１、Ａ^２及びＢ^２は、同じであっても異なっていてもよい。但し、二つのＢ^１又はＢ^２の間に挟まれたＡ^１又はＡ^２は、単結合ではないものとする。
Ｄ^１及びＤ^２は各々独立して、置換基として、炭素原子数１〜２のアルキル基又はアルキルフッ素基を有していてもよいベンゼン環又はナフタレン環を表す。
Ｒ^２は、炭素原子数６〜１８のアルキル基、または２以上のフッ素原子で置換された炭素原子数１〜３のアルキル基を表す。Ｓは、１〜３の整数を表す。）

(Wherein R ¹ is a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, a maleimide group, a carboxyl group, a sulfo group, a nitro group, an amino group, or a hydroxy group Represents a group (however, a carboxyl group and a sulfo group may form a salt with an alkali metal).
X ¹ represents a linking group represented _by- (A ¹ -B ¹ ) _m1- , and X ² represents a linking group represented by-(A ² -B ² ) _n1- . Here, A ¹ and A ² each independently represent a single bond or a divalent hydrocarbon group, and B ¹ and B ² each independently represent a single bond, —O—, —CO—O—, — OCO-, -CONH-, -NHCO-, -NHCO-O-, or -OCONH- is represented. m1 and n1 each independently represents an integer of 0 to 4. However, when m1 or n1 is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different. However, A ¹ or A ² sandwiched between two B ¹ or B ² is not a single bond.
D ¹ and D ² each independently represents a benzene ring or naphthalene ring which may have an alkyl group having 1 to 2 carbon atoms or an alkyl fluorine group as a substituent.
R ² represents an alkyl group having 6 to 18 carbon atoms or an alkyl group having 1 to 3 carbon atoms substituted with two or more fluorine atoms. S represents an integer of 1 to 3. )

  In addition, the present invention provides a liquid crystal pretilt angle imparting agent for a photoalignment film represented by the general formula (1), and photoalignment that exhibits a liquid crystal alignment function by at least one photoisomerization reaction in one molecule. Provided is a composition for a photoalignment film containing a compound having a group.

  Moreover, this invention provides the manufacturing method of the photo-alignment film | membrane which irradiates the light which has anisotropy, after apply | coating the said composition for photo-alignment films | membranes on a board | substrate.

  The liquid crystal pretilt angle imparting agent for a photoalignment film of the present invention can control the pretilt angle of the liquid crystal within a range of up to about 20 ° by adjusting the amount added to the composition for a photoalignment film. In addition, since it has excellent compatibility with the composition for photo-alignment films using azobenzene derivatives, the liquid crystal aligned by the obtained photo-alignment film is free of alignment irregularities and alignment defects, and is uniform and long-term stable over the entire surface. Excellent pretilt angle can be obtained.

  Moreover, the composition for photo-alignment films of the present invention can obtain liquid crystal alignment having a pretilt parallel to the incident surface only by irradiating non-polarized light from an oblique direction with respect to the film surface. Since the polarizing plate in the light irradiation device is unnecessary, the loss of light of the ultraviolet lamp is small, and the light irradiation process in the production line is simplified, which can contribute to the improvement of mass productivity. In addition, since the pretilt of the liquid crystal by the photo-alignment film can be controlled in a range up to about 20 °, it is possible to deal with fluctuations in the pretilt due to different types of liquid crystal and liquid crystal elements in various display modes. .

（式中、Ｒ^１は、（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、（メタ）アクリルアミド基、ビニル基、ビニルオキシ基、マレイミド基、カルボキシル基、スルホ基、ニトロ基、アミノ基、又はヒドロキシ基を表す（但し、カルボキシル基及びスルホ基は、アルカリ金属と塩を形成していてもよい）。
Ｘ^１は、−（Ａ^１−Ｂ^１）_ｍ1−で表される連結基を表し、Ｘ^２は−（Ａ^２−Ｂ^２）_ｎ1−で表される連結基を表す。ここで、Ａ^１及びＡ^２は各々独立して単結合、又は二価の炭化水素基を表し、Ｂ^１及びＢ^２は各々独立して単結合、−Ｏ−、−ＣＯ−Ｏ−、−ＯＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−ＮＨＣＯ−Ｏ−、又は−ＯＣＯＮＨ−を表す。ｍ１及びｎ１は各々独立して０〜４の整数を表す。但し、ｍ１又はｎ１が２以上のとき、複数あるＡ^１、Ｂ^１、Ａ^２及びＢ^２は、同じであっても異なっていてもよい。但し、二つのＢ^１又はＢ^２の間に挟まれたＡ^１又はＡ^２は、単結合ではないものとする。
Ｄ^１及びＤ^２は各々独立して、置換基として、炭素原子数１〜２のアルキル基又はアルキルフッ素基を有していてもよいベンゼン環又はナフタレン環を表す。
Ｒ^２は、炭素原子数６〜１８のアルキル基、または２以上のフッ素原子で置換された炭素原子数１〜３のアルキル基を表す。Ｓは、１〜３の整数を表す。） (Description of liquid crystal pretilt angle imparting agent for photo-alignment film of the present invention)
The liquid crystal pretilt angle imparting agent for a photo-alignment film of the present invention is represented by the general formula (1).

(Wherein R ¹ is a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, a maleimide group, a carboxyl group, a sulfo group, a nitro group, an amino group, or a hydroxy group Represents a group (however, a carboxyl group and a sulfo group may form a salt with an alkali metal).
X ¹ represents a linking group represented _by- (A ¹ -B ¹ ) _m1- , and X ² represents a linking group represented by-(A ² -B ² ) _n1- . Here, A ¹ and A ² each independently represent a single bond or a divalent hydrocarbon group, and B ¹ and B ² each independently represent a single bond, —O—, —CO—O—, — OCO-, -CONH-, -NHCO-, -NHCO-O-, or -OCONH- is represented. m1 and n1 each independently represents an integer of 0 to 4. However, when m1 or n1 is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different. However, A ¹ or A ² sandwiched between two B ¹ or B ² is not a single bond.
D ¹ and D ² each independently represents a benzene ring or naphthalene ring which may have an alkyl group having 1 to 2 carbon atoms or an alkyl fluorine group as a substituent.
R ² represents an alkyl group having 6 to 18 carbon atoms or an alkyl group having 1 to 3 carbon atoms substituted with two or more fluorine atoms. S represents an integer of 1 to 3. )

In general formula (1), in order to efficiently distribute the alkyl group represented by R ² having a role of imparting an arbitrary pretilt angle to the liquid crystal on the surface of the alignment film, to obtain a uniform alignment film, R ¹ Is preferably a group having high affinity for a transparent electrode such as glass or ITO. Therefore, for applications that particularly require adhesion to the substrate, R ¹ in the general formula (1) is a carboxyl group, a sulfo group, a carboxyl group that forms a salt with an alkali metal, a sulfo group that forms a salt with an alkali metal, A nitro group, an amino group, or a hydroxy group is preferred. Among them, a sulfo group, a hydroxy group, a carboxyl group, a carboxyl group that forms a salt with an alkali metal, or a sulfo group that forms a salt with an alkali metal is particularly preferable.
On the other hand, for applications in which stability to light or heat is particularly required, R ¹ in the general formula (1) is preferably a polymerizable group. Examples of the polymerizable group include (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group, and maleimide group. Of these, an acryloyl group and a maleimide group are particularly preferable.
Although there is no particular limitation on the substitution position of these groups with respect to D ¹ , more preferably, when D ¹ is a benzene ring, the position where the azo group is substituted is defined as the 1-position, and the 4-position, 2-position, and 4 Most preferred are substitution at the 3rd and 4th positions. Further, when D ¹ is a naphthalene ring, the position substituted by the azo group is defined as the 1st position, and the 2-position, 3-position, 5-position, 6-position, 7-position, or 8-position of the naphthalene ring is substituted. Preferably it is.
In the case of R ^{1, it} is preferable that a plurality of D ¹ is substituted (that is, when S is 2 or 3), since the affinity for the substrate is increased. The combination of R ¹ is not particularly limited, and may have two groups selected from the group of high affinity groups, or may have two groups selected from the group of polymerizable groups. Alternatively, it may have both one group selected from the group of high affinity groups and one group selected from the group of polymerizable groups. The combination is preferably a combination of a sulfo group and a hydroxy group that forms a salt with an alkali metal, or a combination of a polymerizable group and a sulfo group, a hydroxy group, a carboxyl group, or a sulfo group that forms a salt with an alkali metal.

As X ¹ and X ² , when R ¹ is a group having high affinity, A ¹ , A ² , B ¹ and B ² are preferably a single bond, and when R ¹ is the polymerizable group, B ¹ and B ² is particularly preferably —CO—O— or —OCO—.

R ² represents an alkyl group having 6 to 18 carbon atoms or an alkyl group having 1 to 3 carbon atoms substituted with two or more fluorine atoms.
When R ² is an alkyl group substituted with a fluorine atom, the length of the alkyl group (here, the length of the alkyl group is the length from the carbon atom adjacent to B ² to the terminal carbon atom of the alkyl group). Here, the sum of the number of carbon atoms from the carbon atom adjacent to B ² to the terminal carbon atom of the alkyl group is described as “length”), and the effect of the present invention can be exhibited even if the length is short. it can.
When R ² is an alkyl group not substituted with a fluorine atom, the pretilt angle may not be sufficiently exhibited when the length of the alkyl group is less than 6 in terms of the number of carbon atoms. On the other hand, if the length of the alkyl group exceeds 18 in terms of the number of carbon atoms, it tends to be inferior in compatibility with the composition for photo-alignment films, which causes alignment irregularities and alignment defects of liquid crystals. There is. In order to provide a more stable pretilt angle, the alkyl group is preferably linear. A more preferable range is an alkyl group having 6 to 14 carbon atoms, and an alkyl group having 6 to 12 carbon atoms is most preferable.

Preferred combinations of the groups of the general formula (1) are shown below.
(1) In the general formula (1), R ¹ is a carboxyl group, a sulfo group, a carboxyl group that forms a salt with an alkali metal, a sulfo group that forms a salt with an alkali metal, a nitro group, an amino group, or a hydroxy group. D ¹ is a benzene ring or a naphthalene ring, D ² is a benzene ring, X ² is —O—, R ² is an alkyl group having 6 to 18 carbon atoms, and S is 1 or A combination that is an integer of two.

(2) In the general formula (1), R ¹ is an acryloyl group or a maleimide group, D ¹ is a benzene ring or a naphthalene ring, D ² is a benzene ring, and X ² is —O—. R ² is an alkyl group having 6 to 18 carbon atoms, and S is an integer of 2.

(3) In the general formula (1), R ¹ is selected from the group consisting of a carboxyl group, a sulfo group, a carboxyl group that forms a salt with an alkali metal, a sulfo group that forms a salt with an alkali metal, and a hydroxy group. One group selected from the group consisting of an acryloyl group and a maleimide group, D ¹ is a benzene ring or a naphthalene ring, D ² is a benzene ring, X ² is —O—, R ² is an alkyl group having 6 to 18 carbon atoms, and S is an integer of 2.

(Concrete example)
Preferred examples of the liquid crystal pretilt angle imparting agent for photo-alignment films of the present invention include compounds represented by the following general formulas (1-1) to (1-3).

In general formulas (1-1) to (1-3), R ² represents an alkyl group having 6 to 18 carbon atoms, or an alkyl group having 1 to 3 carbon atoms substituted with two or more fluorine atoms. .
In General Formula (1-1), M ¹ represents a hydrogen atom or an alkyl metal. Here, lithium, sodium, potassium, etc. are mentioned as an alkali metal.
In General Formula (1-2), M ² is a hydroxy group or a group represented by the following General Formula (g-1) or (g-2).

In general formulas (g-1) and (g-2), p represents an integer of 1 to 8.
In formula (1-2), M ³ represents a sulfo group, a sulfo group that forms a salt with an alkali metal, a carboxyl group, a carboxyl group that forms a salt with an alkali metal, or —CONH ₂ . Here, lithium, sodium, potassium, etc. are mentioned as an alkali metal.

(Synthesis method (obtainment route))
The liquid crystal pretilt angle imparting agent for a photo-alignment film of the present invention is obtained, for example, by reacting 4-nitrophenol with an alkyl halide to obtain an O-alkyl body, and then reducing the O-alkyl body to obtain an amine body. The diazonium salt can be prepared, and this can be synthesized by a coupling reaction with 6-hydroxy-2-naphthalenesulfonic acid sodium salt.

(How to use) (Description of composition for photo-alignment film)
The liquid crystal pretilt angle imparting agent for photo-alignment film of the present invention is used by adding to the composition for photo-alignment film. Examples of the composition for a photo-alignment film include a composition containing a compound having a group that exhibits a photodimerization reaction such as a cinnamoyl group, a coumarin group, a chalcone group, or a benzophenone group, and a photoisomerization reaction such as an azo group or an anthraquinone group. There are a composition containing a compound having a group that expresses a group, a composition containing a resin that causes photodegradation such as a polyimide resin, and the like. Among them, a liquid crystal alignment function is achieved by at least one photoisomerization reaction in one molecule. A composition containing a compound having a photo-alignable group (hereinafter abbreviated as a photo-alignable group) is preferred. Among them, a compound exhibiting dichroism is preferable because a uniform coating film can be easily formed on a substrate such as glass. The term “dichroism” as used herein refers to a property in which the light absorption spectrum of a molecular chromophore varies depending on the direction of the polarization plane of linearly polarized light. An azobenzene skeleton and an anthraquinone skeleton are known as chromophores exhibiting dichroism.
Among these, azobenzene derivatives are particularly preferable in that they exhibit good photo-alignment properties by irradiation with polarized light. Known azobenzene derivatives can be used. Since the liquid crystal pretilt angle imparting agent for a photo-alignment film of the present invention has an azobenzene skeleton, it is excellent in compatibility with an azobenzene derivative, and a photo-alignment film free from alignment unevenness and alignment defects can be obtained.

  The liquid crystal pretilt angle imparting agent for a photoalignment film of the present invention is preferably added in an amount of 0.1 to 10% by mass relative to the total amount of the compound having a photoalignment group in the composition for a photoalignment film, up to 20 °. A photo-alignment film having a desired pretilt angle can be obtained. As said addition amount, 0.1-10 mass% is preferable in order to hardly generate the defect of a liquid crystal orientation, 0.3-8 mass% is still more preferable, 0.5-7 mass% is further more preferable, 2- 5% by mass is most preferred.

  The azobenzene derivative used in the present invention may have a polymerizable group. Examples of the azobenzene derivative having a polymerizable group include a carboxylic acid having a polymerizable group, a carboxylic acid chloride having a polymerizable group, and a carboxylic acid anhydride having a polymerizable group by a known method. , Etc. can be easily synthesized. An azobenzene derivative having a hydroxy group can be easily synthesized by a known method.

(Polymerizable group)
Examples of the polymerizable group include (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group, maleimide group, azide group, chloromethyl group, epoxy group, and the like. Examples of the derivative having a polymerizable group include cinnamic acid derivatives and thymine derivatives. Among these, (meth) acryloyl group, (meth) acryloyloxy group, maleimide group, (meth) acrylamide group, vinyl group and vinyloxy group are preferable because photopolymerization and thermal polymerization are relatively easy. An acryloyl group, a (meth) acryloyloxy group, a maleimide group, or a (meth) acrylamide group is more preferable.
These polymerizable groups may be bonded to an azobenzene derivative via a linking group such as an alkylene group and / or a phenylene group, and the linking group includes an ester bond, an ether bond, an imide bond, or an amide bond. You may have.

  Among the azobenzene derivatives used in the present invention, the compound represented by the general formula (2) exhibits high solubility in water or a polar organic solvent, and exhibits good affinity for glass and the like. A composition for a photo-alignment film formed by dissolving the compound in water or a polar organic solvent is applied to a substrate such as glass, and then the water or the polar organic solvent is removed. A smooth coating film can be formed.

In the formula, R ³ and R ⁴ are each independently a hydroxy group, or a group consisting of a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, and a maleimide group. Represents a polymerizable functional group selected from: Among the polymerizable groups, a (meth) acryloyl group, a (meth) acryloyloxy group, or a (meth) acrylamide group is preferable because photopolymerization and thermal polymerization are relatively easy. A maleimide group is more preferable because a polymerization initiator is not required.

X ³ represents a single bond when R ³ is a hydroxy group, and represents a linking group represented by — (A ³ -B ³ ) _{m 2} — when R ³ is a polymerizable functional group, and X ⁴ represents R ^{When 4} is a hydroxy group, it represents a single bond, and when R ⁴ is a polymerizable functional group, it represents a linking group represented _by- (A ⁴ -B ⁴ ) _n2- .
Here, A ³ and A ⁴ each independently represent a single bond or a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include alkylene groups having 1 to 20 carbon atoms such as ethylene group, methylene group, propylene group, pentamethylene group and heptylene group; 3 to 3 carbon atoms such as cyclopropylene group and cyclohexylene group. 20 cycloalkylene group; arylene groups having 6 to 20 carbon atoms such as phenylene group and naphthylene group. Among these, an alkylene group is preferable, and an alkylene group having 1 to 6 carbon atoms is more preferable.

B ³ and B ⁴ each independently represents a single bond, —O—, —CO—O—, —OCO—, —CONH—, —NHCO—, —NHCO—O—, or —OCONH—. m2 and n2 each independently represents an integer of 0 to 4. However, when m2 or n2 is 2 or more, a plurality of A ³ , B ³ , A ⁴ and B ⁴ may be the same or different. However, A ³ or A ⁴ sandwiched between two B ³ or B ⁴ is not a single bond. Specifically, when m2 is ^{2, - (A 1 -B 1} ) m - linking group represented _{by, -CH 2 CH 2 -O-CH} 2 CH 2 CH 2 CH 2 -CO-O- or _{represents -O-CH 2 CH 2 CH 2} -CO-O- and the like, when n2 is ^{2, - (a 2 -B 2} ) n - linking group represented by, - _{(CH 2) 6} —O—Ph (phenylene group) —CO—O— or the like is represented.

R ⁵ and R ⁶ each independently represents a halogen atom, a carboxyl group, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, a methoxy group, or a methoxycarbonyl group. However, the carboxyl group may form a salt with the alkali metal. Examples of the halogen atom include a fluorine atom and a chlorine atom. Examples of the halogenated methyl group include a trichloromethyl group and a trifluoromethyl group. Examples of the halogenated methoxy group include a chloromethoxy group and a trifluoromethoxy group. Among these, a halogen atom, a carboxyl group, a halogenated methyl group, or a halogenated methoxy group is preferable, and a carboxyl group or a trifluoromethyl group is particularly preferable in that good orientation can be obtained. Further, when R ⁵ and R ⁶ are substituted at the meta positions of the phenylene group at both ends of the 4,4′-bis (phenylazo) biphenyl skeleton, an alignment film having a large alignment regulating force can be obtained by photo-alignment. preferable.

R ⁷ and R ⁸ each independently represents a carboxyl group, a sulfo group, a nitro group, an amino group, or a hydroxy group. However, the carboxyl group and the sulfo group may form a salt with an alkali metal such as lithium, sodium or potassium. Among these, when R ⁷ and R ⁸ are a carboxyl group or a salt thereof, a sulfo group or a salt thereof, or a hydroxy group, the affinity for the substrate is high, and a uniform film can be obtained even with a small film thickness. It is preferable because a liquid crystal alignment regulating force can be obtained. In particular, a sulfo group or an alkali metal salt thereof is preferable. Further, it is particularly preferable that R ⁷ and R ⁸ are substituted at the 2,2 ′ positions of the 4,4′-bis (phenylazo) biphenyl skeleton, since excellent photoalignment properties can be obtained.

  As the compound represented by the general formula (2), specifically, a compound described in JP-A No. 2002-250924 or a compound described in SID'01 Digest, 1170 (2001) can be used. It can be easily synthesized by the method described in the publication. Moreover, several types can also be mixed and used.

(solvent)
The composition for photo-alignment films of the present invention is used after being dissolved in an appropriate solvent. At this time, the solvent used is not particularly limited, and any solvent may be used as long as the compound exhibits good solubility. Examples thereof include N-methylpyrrolidone, dimethylformamide, butyl cellosolve, gamma-butyrolactone, chlorobenzene, dimethyl sulfoxide, dimethylacetamide, tetrahydrofuran and the like. Among these solvents, N-methylpyrrolidone, butyl cellosolve, gamma-butyrolactone, dimethylformamide are used because the coating property of the composition for photo-alignment film on a substrate such as glass is good and a uniform film is obtained. Is particularly preferred. Moreover, you may add a well-known and usual additive in the range which does not impair the effect of this invention.

(Description of manufacturing method)
(Coating, substrate)
The composition for photo-alignment films of the present invention is applied on a substrate by a method such as spin coating or printing and dried. The substrate to be used is a substrate usually used for a liquid crystal display element, and is a material having heat resistance capable of withstanding heating at the time of drying after application of the alignment film solution or at the time of bonding when assembled to the liquid crystal element. There is no particular limitation. Examples of such a substrate include a glass substrate.

(Optical alignment operation)
The coating film of the composition for photo-alignment films obtained by the above method is irradiated with anisotropic light to impart a liquid crystal alignment function (hereinafter abbreviated as photo-alignment operation). Examples of anisotropic light used in the photo-alignment operation include linearly polarized light and elliptically polarized light, or non-polarized light from a direction oblique to the substrate surface. The polarized light may be either linearly polarized light or elliptically polarized light, but it is preferable to use linearly polarized light having a high extinction ratio in order to perform photoalignment efficiently.

  Moreover, since it is necessary to use a polarizing filter or the like in order to obtain polarized light in the light irradiation device, there is a disadvantage that the light intensity irradiated to the film surface is reduced. The irradiation method does not require a polarizing filter or the like in the irradiation device, and has an advantage that a large irradiation intensity can be obtained and the irradiation time for photo-alignment can be shortened. At this time, the incident angle of non-polarized light is preferably in the range of 10 ° to 80 ° with respect to the normal to the substrate. In consideration of the uniformity of the irradiation energy on the irradiated surface, the pretilt angle obtained, the alignment efficiency, etc. A range of 60 ° is more preferred and 45 ° is most preferred.

The light to be irradiated may be light in a wavelength region in which the photoalignable group of the compound used in the composition for photoalignment film has absorption. For example, when the photo-alignment group has an azobenzene structure, ultraviolet rays having a wavelength of 350 to 500 nm that have strong absorption due to the π → π ^* transition of azobenzene are particularly preferable.
Examples of the light source for irradiation light include xenon lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and the like. In particular, when the photo-alignment group has an azobenzene structure, it is possible to effectively use an ultra-high pressure mercury lamp having a particularly large emission intensity of ultraviolet light at 365 nm.
Ultraviolet linearly polarized light can be obtained by passing the light from the light source through a polarizing prism such as a polarizing filter, Glan-Thompson, and Glan-Teller.
Moreover, it is particularly preferable that the irradiated light is substantially parallel light regardless of whether polarized light or non-polarized light is used.

(Polymerization operation)
When the composition for photo-alignment films of the present invention has a polymerizable group, after performing the photo-alignment operation, a polymerization operation for polymerizing the polymerizable group with active energy rays or heat is performed.
The polymerization operation is performed by irradiating with active energy rays or heating. As the active energy ray, light having a wavelength different from that used in the photo-alignment operation, that is, light in a wavelength region that is not absorbed by the photo-alignment group of the compound used in the composition for the photo-alignment film is preferable. It is preferable to irradiate non-polarized ultraviolet light having a wavelength of 200 to 320 nm. Thereby, it can superpose | polymerize, without disturbing the orientation state of the composition for photo-alignment films | membranes fixed by photo-alignment operation.

  On the other hand, when the polymerization operation is performed by heating, it is performed by heating the substrate. Although the heating temperature depends on the cleavage temperature of the thermal polymerization initiator to be used, it is usually preferably in the range of 80 to 300 degrees, particularly preferably in the range of 80 to 200 degrees, and further preferably in the range of 100 to 200 degrees.

(Photopolymerization initiator)
In the case of polymerization by light irradiation, it is preferable to use a photopolymerization initiator as a polymerization initiator. As the photopolymerization initiator, known ones can be used. For example, 2-hydroxy-2-methyl-1-phenylpropan-1-one ("Darocur 1173" manufactured by Merck & Co.), 1-hydroxycyclohexyl phenyl ketone (Ciba "Irgacure 184" manufactured by Geigy Corporation), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one ("Darocur 1116" manufactured by Merck & Co.), 2-methyl-1-[(methylthio ) Phenyl] -2-morpholinopropane-1 ("Irgacure 907" manufactured by Ciba-Geigy), benzyldimethyl ketal ("Irgacure 651" manufactured by Ciba-Geigy), 2,4-diethylthioxanthone (Nippon Kayaku Co., Ltd.) "Kayakyu DETX") and ethyl p-dimethylaminobenzoate ("Kayakyu" manufactured by Nippon Kayaku Co., Ltd.) EPA "), isopropylthioxanthone (" Kantacur-ITX "manufactured by Ward Prekinsop) and ethyl p-dimethylaminobenzoate, acylphosphine oxide (" Lucirin TPO "manufactured by BASF), and the like. Can be mentioned. Among these, 1-hydroxycyclohexyl phenyl ketone having absorption on the short wavelength side is preferable.

(Thermal polymerization initiator)
On the other hand, in the case of polymerization by heating, it is preferable to use a thermal polymerization initiator as the polymerization initiator. Known and commonly used thermal polymerization initiators can be used, such as benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, 1,1-di (tertiary butyl peroxy) -3,3,5-trimethylcyclohexane. , N-butyl-4,4′-di (tertiarybutylperoxy) valerate, peroxides such as dicumyl peroxide; azo compounds such as 7-azobisisobutylnitrile; tetramethylthiuram disulfide, etc. Can be mentioned.

(Liquid crystal display element)
An example of a method for producing a liquid crystal display element using the photo-alignment film obtained by the method for producing a photo-alignment film of the present invention will be described below. That is, after applying the composition for a photo-alignment film in the present invention on the surface of the two glass substrates provided with transparent electrodes such as ITO and drying, the polymerization operation is performed while performing the photo-alignment operation. To create a photo-alignment film. Next, the surface on which the photo-alignment film is provided is opposed so that the photo-alignment directions are orthogonal to each other through a spacer, and liquid crystal is injected into the gap. A TN liquid crystal display element is manufactured by attaching a polarizing plate to the outside of the liquid crystal cell thus produced so that the alignment direction of the photo-alignment film on each substrate matches the transmission polarization direction. Can do.

  Hereinafter, the present invention will be described more specifically with reference to examples. Unless otherwise specified, “part” and “%” are based on mass.

(Production Example 1)
Synthesis of compound (1-1a) in which R ² is an alkyl group having 6 carbon atoms and M ¹ is sodium in general formula 1-1

  4.62 g of 4-nitrophenol was dissolved in 100 ml of N, N-dimethylformamide, and 36.0 g of potassium carbonate was added. The reaction solution was heated to 60 ° C. with stirring, and 6.87 g of 1-bromohexane was added dropwise over 2 hours. After completion of the dropwise addition, stirring was continued for another 30 minutes. Next, the reaction solution was concentrated under reduced pressure to remove the solvent, and the residue was dissolved in toluene, washed with a 20% aqueous sodium hydroxide solution and then with water, dried over anhydrous magnesium sulfate. The toluene solution was filtered and the filtrate was concentrated under reduced pressure to obtain 7.70 g of 4-hexyloxynitrobenzene as a solid.

  4-Hexyloxynitrobenzene To a solution of 7.60 g of ethanol in 100 ml of ethanol was added 0.35 g of 5% Pt-carbon, and the mixture was stirred at room temperature for 3 hours in a hydrogen atmosphere. After completion of the reaction, the reaction solution was filtered, and the filtrate was concentrated under reduced pressure to obtain 6.40 g of 4-hexyloxyaniline as a solid.

2.0 g of 4-hexyloxyaniline was suspended in 30 ml of 3% HCl aqueous solution, and 10 ml of 0.72 g sodium nitrite aqueous solution was added dropwise while stirring with ice cooling (0 to 5 degrees). After completion of the dropwise addition, the mixture was further stirred for 2 hours to prepare a diazonium salt solution.
6-Hydroxy-2-naphthalenesulfonic acid sodium salt 2.54 g was dissolved in 55 ml of 5% aqueous sodium carbonate solution by heating, and then a diazonium salt solution adjusted with ice-cooling and stirring at 5 degrees was added (an orange precipitate was formed). ). After further stirring for 2 hours, 10 g of sodium chloride was added for salting out. The precipitate was filtered off, washed with acetone and then dried under reduced pressure to obtain 4.2 g of a compound (1-1a) in which R ² is an alkyl group having 6 carbon atoms and M ¹ is sodium in the general formula 1-1. It was.

1H-NMR (DMSO-d6) δ ppm: 0.86 (t, 3H, j = 6.8 Hz), 1.2 to 1.5 (m, 6H), 1.73 (m, 2H), 4.05 (T, 2H, j = 6.4 Hz), 7.12 (d, 2H, j = 9.0 Hz), 7.13 (d, 1H, j = 9.2 Hz), 7.84 (d, 1H, j = 8.7 Hz), 7.96 (d, 2H, j = 9.0 Hz), 8.02 (d, 1H, j = 9.2 Hz), 8.11 (s, 1H), 8.65 ( d, 1H, j = 8.7 Hz). 13C-NMR (DMSO-d6) δ ppm: 13.9, 22.0, 25.1, 28.5, 31.0, 68.0, 115.4, 120.7, 121.7, 122.9, 125.0, 126.0, 126.8, 128.7, 132.4, 136.4, 142.5, 144.5, 157.7, 160.5.

(Production Example 2)
Synthesis of Compound (1-1b) in which R ² is an alkyl group having 12 carbon atoms and M ¹ is sodium in General Formula (1-1) in Production Example 1, 1 is substituted for 1-bromohexane. - other using bromo dodecane 8.96g in the same manner as in production example 1, in the general formula (1-1) ^{R 2} is an alkyl group having a carbon number of 12, compound ^{M 1} is sodium (1- 1b) 1.65 g was obtained.

1H-NMR (DMSO-d6) δ ppm: 0.83 (t, 3H, j = 7.0 Hz), 1.2 to 1.5 (m, 18H), 1.73 (m, 2H), 4.06 (T, 2H, j = 6.4 Hz), 7.13 (d, 2H, j = 8.9 Hz), 7.14 (d, 1H, j = 9.0 Hz), 7.84 (dd, 1H, j = 1.5, 8.7 Hz), 7.97 (d, 2H, j = 8.9 Hz), 8.04 (d, 1H, j = 9.0 Hz), 8.11 (d, 1H, j = 1.5 Hz), 8.65 (d, 1H, 8.7 Hz). 13C-NMR (DMSO-d6) δ ppm: 13.9, 22.1, 25.4, 28.5, 28.7, 28.9, 29.0, 31.3, 68.0, 115.5 121.3, 122.9, 126.1, 127.0, 128.6, 132.2, 136.6, 142.2, 144.8, 157.4, 160.6.

(Production Example 3)
Synthesis of compound (1-1c) in which R ² is a trifluoromethyl group and M ¹ is sodium in the general formula (1-1), 2.00 g of 4-trifluoromethoxyaniline is added to 33 ml of 3% HCl aqueous solution. The suspension was suspended, and 10 ml of a 0.78 g sodium nitrite aqueous solution was added dropwise while stirring on ice (0 to 5 degrees). After completion of the dropwise addition, the mixture was further stirred for 2 hours to prepare a diazonium salt solution.
6-Hydroxy-2-naphthalenesulfonic acid sodium salt 2.78 g was dissolved by heating in 60 ml of 5% aqueous sodium carbonate solution, and then the diazonium salt solution adjusted with ice cooling and stirring at 5 degrees was added. After further stirring for 2 hours, 10 g of sodium chloride was added for salting out. The precipitate was filtered off, washed with water and dried under reduced pressure to obtain 3.40 g of compound (a-3) in which R ² is a trifluoromethyl group and M ¹ is sodium in the general formula (1-1). It was.

  1H-NMR (DMSO-d6) δ ppm: −4.52 (brd), 6.93 (d, 1H, j = 9.5 Hz), 7.52 (d, 2H, j = 9.0 Hz), 7. 82 (d, 2H, j = 8.4 Hz), 8.02 (m, 4H), 8.50 (d, 1H, j = 8.4 Hz). 13C-NMR (DMSO-d6) δ ppm: 118.4, 120.8, 121.0, 121.8, 122.4, 124.1, 125.7, 126.7, 127.2, 129.5 132.6, 140.5, 144.4, 146.0, 147.4, 168.7.

(Production Example 4)
Synthesis of compound (1-2d) wherein R ² is an alkyl group having 9 carbon atoms and M ³ is a carboxyl group in the general formula (1-2)

200 g of N, N-dimethylformamide (DMF) was added to 27.3 g of 4-nitrophenol, 38.0 g of 1-bromononane and 38 g of potassium carbonate, and the mixture was heated and stirred at 90 ° C. for 2 hours. After completion of the reaction, the reaction solution was cooled, and the reaction solution was filtered and concentrated under reduced pressure to remove DMF. The residue was dissolved in ethyl acetate, the organic layer was washed with 1% aqueous sodium hydroxide solution and then with pure water, and then ethyl acetate was removed under reduced pressure to obtain 48.5 g of 4-nonyloxynitrobenzene.
To the obtained 4-nonyloxynitrobenzene, 56 g of reduced iron, 300 g of water, and 0.5 g of ammonium chloride were added and stirred at 95-100 ° C. for 5 hours. The reaction product was filtered, and the filtrate was concentrated under reduced pressure to obtain 40.0 g of 4-nonyloxyaniline.
438 g of 3% dilute hydrochloric acid was added to 33 g of 4-nonyloxyaniline, heated in a water bath for 10 minutes, then cooled to 0-5 ° C., and then an aqueous solution containing 10.4 g of sodium nitrite was added dropwise over 5 minutes. did. After 1 hour, the mixture was added dropwise into a mixture of 135 g of 8% aqueous sodium carbonate and 16 g of methyl salicylate, and the mixture was further stirred at room temperature for 2 hours. After completion of stirring, hydrochloric acid was added to adjust the pH to 2-3, and after 30 minutes, the precipitate was filtered off from the mixed solution. The precipitate was recrystallized three times using a mixed solvent of toluene / 2-propanol (ratio 1: 3) to obtain 35.0 g of a compound represented by the following formula (a-1).

  21.5 g of compound (a-1), 8.0 g of 6-chlorohexanol, 13.8 g of potassium carbonate and 0.8 g of sodium iodide were dissolved in 150 g of DMF, and then the mixture was refluxed at 120 ° C. For 4 hours. The reaction product was cooled and filtered, DMF was removed under reduced pressure, the residue was dissolved in ethyl acetate, and the organic layer was washed twice with pure water and concentrated. The obtained solid was put into a mixture of 30 g of 2-propanol, 200 g of water and 10 g of sodium hydroxide, and heated to 80 ° C. After 4 hours, the mixture was cooled and the pH was adjusted to 3 or less. After 30 minutes, the mixture was filtered and dried to obtain 24.2 g of a compound represented by the following formula (a-2).

  34.0 g of the compound (a-2), 50 g of acrylic acid and 1.3 g of 4-toluenesulfonic acid were dissolved in 350 ml of toluene, heated to 110 ° C. under reflux, and stirred for 5 hours. Toluene and excess acrylic acid were removed from the reaction mixture under reduced pressure. The obtained solid was recrystallized with a mixed solvent composed of 12 g of ethyl acetate and 60 g of methyl alcohol to obtain 19.0 g of a compound represented by the formula (1-2d).

  1H-NMR (DMSO-d6) δ ppm: 0.91 (t, 3H), 1.31 to 2.10 (m, 22H), 4.06 (t, 2H), 4.21 (t, 2H), 4.35 (t, 2H), 5.83 to 6.41 (m, 3H), 7.02 (m, 2H), 7.17 (d, 1H), 7.92 (m, 2H), 8 .10 (m, 1H), 8.75 (d, 1H).

(Production Example 5)
Synthesis of compound (1-2e) wherein R ² is an alkyl group having 9 carbon atoms and M ³ is —CONH ₂ in the general formula (1-2)

  1.1 g of the compound (1-2d) was dissolved in 30 g of dichloromethane, 1.5 g of thionyl chloride was added dropwise while adding 3 drops of DMF and heating to reflux. The reaction was stopped after 4 hours, the solvent was removed under reduced pressure, and the resulting solid was dissolved in 5 g of dry THF. The above THF solution was added dropwise to a vigorously stirred 40 g aqueous ammonia in an ice bath to obtain a yellow precipitate. Further, after 1 hour, the precipitate was filtered off and dried to obtain 0.9 g of a compound represented by the formula (1-2e).

  1H-NMR (DMSO-d6) δ ppm: 0.86 (t, 3H), 1.23-1.75 (m, 22H), 4.07 (t, 2H), 4.12 (t, 2H), 4.22 (t, 2H), 5.92-6.30 (m, 3H), 7.11 (m, 2H), 7.33 (d, 1H), 7.64 (s, 1H), 7 .71 (s, 1H), 7.86 (m, 2H), 7.97 (m, 1H), 8.26 (d, 1H).

Example 1
According to the method described in JP-A-2002-250924, a compound (b) represented by the following formula was obtained.

  100 parts by mass of the compound (b) and 2 parts by mass of a thermal polymerization initiator “V-65” (manufactured by Wako Pure Chemical Industries, Ltd.) are mixed in a mixed solvent of 50 parts by mass of N-methyl-2-pyrrolidone and 50 parts by mass of butoxyethanol. It was made to melt | dissolve and it was set as the solution of 1 mass% of non volatile matters. This solution was filtered through a 0.1 μm filter. To this, the compound (1-1a) obtained in Production Example 1 was added in an amount of 1, 2, 5 mass% with respect to the compound (b) to prepare a composition for a photoalignment film.

The composition for photo-alignment film was uniformly coated on a glass substrate with a spin coater and dried at 100 ° C. for 1 minute. The surface of the coating film thus obtained was irradiated with non-polarizing ultraviolet rays with an integrated light amount of 5 J / cm ² and a wavelength of around 365 nm from 45 ° with respect to the substrate normal line by an ultra-high pressure mercury lamp, and the photo-alignment operation was performed. went.

  An epoxy adhesive containing styrene beads having a diameter of 10 μm was applied to the periphery of the obtained substrate with a photo-alignment film, and the layers were pressure-bonded so that the alignment planes face each other and the directions of polarized light were parallel. Next, it heated at 150 degreeC under nitrogen atmosphere for 1 hour, the epoxy adhesive and the photo-alignment film composition were thermally polymerized, and the liquid crystal cell was obtained. From the liquid crystal injection port of the liquid crystal cell, nematic liquid crystal “11-3323” (Dainippon Ink Chemical Co., Ltd.) was injected in the isotropic phase to obtain a liquid crystal element. This was evaluated for liquid crystal alignment and pretilt angle. Next, the evaluation method is shown.

A. Evaluation of Liquid Crystal Alignment A polarizing microscope was used to evaluate the liquid crystal alignment, and the change over time in alignment unevenness, alignment defects, and alignment uniformity was visually observed.

B. Evaluation of the pretilt angle The pretilt angle of the liquid crystal element is measured by the rotating crystal method [T. J. et al. Schuffer, et al. , J .; Appl. Phys. , Vol. 48, 1783 (1977)].

  Table 1 shows the evaluation results of Example 1. As a result, a larger pretilt angle was obtained as the amount of compound (1-1a) added was increased.

(Example 2)
A liquid crystal device was produced in the same manner as in Example 1 except that the compound (1-1b) obtained in Production Example 2 was used instead of the compound (1-1a). Table 1 shows the evaluation results of Example 2. As a result, a larger pretilt angle was obtained as the amount of additive (1-1b) increased.

(Example 3)
A liquid crystal device was produced in the same manner as in Example 1 except that the compound (1-1c) obtained in Production Example 3 was used instead of the compound (1-1a). Table 1 shows the evaluation results of Example 3. As a result, a larger pretilt angle was obtained as the additive (1-1c) was added.

Example 4
A liquid crystal device was produced in the same manner as in Example 1 except that the compound (1-2d) obtained in Production Example 4 was used instead of the compound (1-1a). Table 1 shows the evaluation results of Example 4.

(Example 5)
A liquid crystal device was produced in the same manner as in Example 1 except that the compound (1-2e) obtained in Production Example 5 was used instead of the compound (1-1a). Table 1 shows the evaluation results of Example 5.

(Comparative example)
A liquid crystal device was produced in the same manner as in Example 1 except that the compound (1-1a) was not used. Table 1 shows the evaluation results of the comparative examples. As a result, the pretilt angle was the lowest at 3.61 °.

Claims (8)

A liquid crystal pretilt angle imparting agent for a photo-alignment film, which is represented by the general formula (1).

(Wherein R ¹ is a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, a maleimide group, a carboxyl group, a sulfo group, a nitro group, an amino group, or a hydroxy group Represents a group (however, a carboxyl group and a sulfo group may form a salt with an alkali metal).
X ¹ represents a linking group represented _by- (A ¹ -B ¹ ) _m1- , and X ² represents a linking group represented by-(A ² -B ² ) _n1- . Here, A ¹ and A ² each independently represent a single bond or a divalent hydrocarbon group, and B ¹ and B ² each independently represent a single bond, —O—, —CO—O—, — OCO-, -CONH-, -NHCO-, -NHCO-O-, or -OCONH- is represented. m1 and n1 each independently represents an integer of 0 to 4. However, when m1 or n1 is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different. However, A ¹ or A ² sandwiched between two B ¹ or B ² is not a single bond.
D ¹ and D ² each independently represents a benzene ring or naphthalene ring which may have an alkyl group having 1 to 2 carbon atoms or an alkyl fluorine group as a substituent.
R ² represents an alkyl group having 6 to 18 carbon atoms or an alkyl group having 1 to 3 carbon atoms substituted with two or more fluorine atoms. S represents an integer of 1 to 3. ) In the general formula (1), R ¹ is a carboxyl group, a sulfo group, a carboxyl group that forms a salt with an alkali metal, a sulfo group that forms a salt with an alkali metal, a nitro group, an amino group, or a hydroxy group; ¹ is a naphthalene ring, D ² is a benzene ring, X ² is —O—, R ² is an alkyl group having 6 to 18 carbon atoms, and S is an integer of 1 or 2. The liquid crystal pretilt angle imparting agent for a photo-alignment film according to claim 1. The photo-alignment of Claim 1 whose liquid crystal pretilt angle providing agent for photo-alignment films represented by the said General formula (1) is a compound represented by General formula (1-1)-(1-3). Liquid crystal pretilt angle imparting agent for film.

(In General Formulas (1-1) to (1-3), R ² represents an alkyl group having 6 to 18 carbon atoms, or an alkyl group having 1 to 3 carbon atoms substituted with two or more fluorine atoms. To express.
In General Formula (1-1), M ¹ represents a hydrogen atom or an alkyl metal.
In General Formula (1-2), M ² is a hydroxy group or a group represented by the following General Formula (g-1) or (g-2).

In general formulas (g-1) and (g-2), p represents an integer of 1 to 8.
In formula (1-2), M ³ represents a sulfo group, a sulfo group that forms a salt with an alkali metal, a carboxyl group, a carboxyl group that forms a salt with an alkali metal, or —CONH ₂ . ) A liquid crystal pretilt angle imparting agent for a photo-alignment film represented by the general formula (1) and a compound having a photo-alignment group that exhibits a liquid crystal alignment function by a photoisomerization reaction in one molecule A composition for a photo-alignment film, characterized in that: The composition for a photoalignment film according to claim 4, wherein the compound having a photoalignment group that exhibits a liquid crystal alignment function by at least one photoisomerization reaction in one molecule is an azobenzene derivative. The compound having a photoalignable group that exhibits a liquid crystal alignment function by at least one photoisomerization reaction in one molecule is represented by the general formula (2).

(In the formula, R ³ and R ⁴ each independently comprise a hydroxy group, or a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, and a maleimide group. X ³ represents a single bond when R ³ is a hydroxy group, and represents-(A ³ -B ³ ) _{m 2-} when R ³ is a polymerizable functional group. X ⁴ represents a single bond when R ⁴ is a hydroxy group, and X ⁴ represents a linking group represented by — (A ⁴ -B ⁴ ) _n2 — when R ⁴ is a polymerizable functional group. Here, A ³ and A ⁴ each independently represent a single bond or a divalent hydrocarbon group, and B ³ and B ⁴ each independently represent a single bond, —O—, —CO—O—. , -OCO-, -CONH-, -NHCO-, -NHCO-O-, or -O ONH- is .m2 and n2 represent a represent each independently integers from 0 to 4. However, when m2 or n2 is 2 or more, a plurality of ^{A 3,} B ^{3, A 4} and ^{B 4} are the same However, A ³ or A ⁴ sandwiched between two B ³ or B ⁴ is not a single bond.
R ⁵ and R ⁶ each independently represents a halogen atom, a carboxyl group, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, a methoxy group, or a methoxycarbonyl group. However, the carboxyl group may form a salt with the alkali metal.
R ⁷ and R ⁸ each independently represents a carboxyl group, a sulfo group, a nitro group, an amino group, or a hydroxy group. However, the carboxyl group and the sulfo group may form a salt with the alkali metal. The composition for photo-alignment films according to claim 4 or 5, which is a compound represented by The composition for photo-alignment films according to any one of claims 4 to 6, comprising 0.1 to 10% by mass of a liquid crystal pretilt angle imparting agent for photo-alignment films represented by the general formula (1). A method for producing a photo-alignment film, comprising applying the composition for a photo-alignment film according to claim 4 on a substrate and then irradiating light having anisotropy.