JP2022120662A - Composition for forming photo-alignment film, photo-alignment film, laminate and polarizing element - Google Patents

Abstract

The present invention provides a composition for forming a photo-alignment film, which can form a photo-alignment film having good adhesion to a substrate and has improved liquid stability. A composition for forming a photo-alignment film, comprising a photo-alignment polymer having a photoreactive group, a silane coupling agent, an acid and a solvent. [Selection figure] None

Description

The present invention relates to a composition for forming a photo-alignment film, a photo-alignment film, a laminate and a polarizing element.

A polarizing element including a laminate obtained by laminating a photo-alignment film and a polarizing film on a substrate is known, and the photo-alignment film of the polarizing element contains a photoreactive group that causes a dimerization reaction. It is known to apply a composition for coating to a substrate (Patent Document 1). In such a laminate, attempts have been made to further improve the adhesion between the photo-alignment film and the base material to further suppress the peeling.
For example, in Patent Document 2, a liquid crystal aligning agent containing a photo-alignable polymer and a silane compound is used as a liquid crystal aligning agent suitable for a retardation film, which can form a liquid crystal aligning film having good adhesion to a substrate. disclosed.

JP 2017-102479 JP 2014-123091

However, in the composition for forming a photo-alignment film as described above, in addition to the good adhesion between the photo-alignment film obtained from the composition and the substrate, the liquid stability of the composition for forming a photo-alignment film is improved. Improvement was required.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a composition for forming a photo-alignment film that can form a photo-alignment film with good adhesion to a substrate and has improved liquid stability.

The present inventors have made intensive studies to solve the above problems, and found that a composition for forming a photo-alignment film containing a photo-alignable polymer having a photoreactive group, a silane coupling agent, an acid and a solvent solves the above problems. We have found that the problem can be solved, and have completed the present invention. That is, the present invention includes the following preferred aspects.

[1] A composition for forming a photo-alignment film, containing a photo-alignment polymer having a photoreactive group, a silane coupling agent, an acid and a solvent.
[2] The composition according to [1], wherein the photo-orientable polymer has a photoreactive group that undergoes a dimerization reaction.
[3] The composition according to [1] or [2], wherein the photo-orientable polymer is a (meth)acrylic polymer.
[4] The composition according to any one of [1] to [3], wherein the photo-orientable polymer further has a carboxyl group.
[5] The composition according to any one of [1] to [4], wherein the photo-orientable polymer has a weight average molecular weight of 10,000 or more and 1,000,000 or less.
[6] The composition according to any one of [1] to [5], wherein the silane coupling agent has at least one group selected from the group consisting of primary amino groups and secondary amino groups.
[7] The content of the silane coupling agent is 0.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the photo-alignable polymer, according to any one of [1] to [6]. Composition.
[8] The composition according to any one of [1] to [7], wherein the acid contains at least one selected from the group consisting of formic acid, toluenesulfonic acid, acrylic acid and acetic acid.
[9] The composition according to any one of [1] to [8], wherein the acid and the silane coupling agent have a molar ratio of 1 or more and 50 or less.
[10] A photo-alignment film obtained by curing the composition according to any one of [1] to [9].
[11] A laminate comprising a substrate and the photo-alignment film of [10].
[12] The laminate according to [11], wherein the film thickness of the substrate is 1 μm or more and 20 μm or less.
[13] A polarizing element comprising a substrate, the photo-alignment film of [10] and a polarizing film.
[14] The polarizing element of [13], which has a thickness of 1 μm or more and 10 μm or less.

ADVANTAGE OF THE INVENTION According to this invention, the composition for photo-alignment film formation which can form a photo-alignment film with favorable adhesiveness with a base material, and has improved liquid stability can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the gist of the present invention.

[Composition for forming a photo-alignment film]
The composition for forming a photo-alignment film of the present invention contains a photo-alignment polymer having a photoreactive group, a silane coupling agent, an acid and a solvent.

[Photo-alignable polymer]
The photo-orientable polymer of the present invention has photoreactive groups. A photoreactive group refers to a group that exhibits liquid crystal alignment ability upon irradiation with light (light irradiation). Specifically, the group involved in the photoreaction that is the origin of the liquid crystal alignment ability, such as alignment induction of polymer molecules caused by light irradiation or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction. mentioned. The photoreactive group is preferably a group having an unsaturated bond, particularly a double bond, such as carbon-carbon double bond (C=C bond), carbon-nitrogen double bond (C=N bond), nitrogen-nitrogen A group having at least one selected from the group consisting of a double bond (N=N bond) and a carbon-oxygen double bond (C=O bond) is preferred. The number of photoreactive groups possessed by the photoorientable polymer may be one or two or more.

Photoreactive groups having a C═C bond include, for example, vinyl groups, polyene groups, stilbene groups, stilbazole groups, stilbazolium groups, chalcone groups and cinnamoyl groups. Examples of the photoreactive group having a C═N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. The photoreactive group having an N=N bond includes, for example, an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Photoreactive groups having a C═O bond include, for example, a benzophenone group, a coumarin group, an anthraquinone group and a maleimide group. These groups may have substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups, and halogenated alkyl groups. Among them, from the viewpoint of excellent orientation and reactivity, the photo-alignable polymer preferably has a photoreactive group that causes a dimerization reaction or a photocrosslinking reaction, and may have a photoreactive group that causes a dimerization reaction. more preferred.

A dimerization reaction is a reaction in which an addition reaction occurs between two groups by the action of light, typically forming a ring structure. The group that causes such a dimerization reaction is a group containing a carbon-carbon double bond (C=C bond) or a carbon-oxygen double bond (C=O bond) that causes a dimerization reaction upon irradiation with light, Examples thereof include a group having a cinnamoyl structure, a group having a chalcone structure, a group having a coumarin structure, a group having a benzophenone structure, a group having an anthracene structure, and the like. Among them, a group having a cinnamoyl structure and a group having a chalcone structure are preferable, and a group having a cinnamoyl structure is more preferable, because the reactivity can be easily controlled and the alignment control force is exhibited at the time of photoalignment. In addition, the group having the above structure is advantageous in that the amount of polarized light irradiation required for photo-alignment is relatively small, and a photo-alignment film excellent in thermal stability and stability over time can be easily obtained.

In the present invention, it is easy to form a photo-alignment film having good adhesion to a substrate, and it is easy to obtain a composition for a photo-alignment film having improved liquid stability. It is preferable to have a photoreactive group that causes a quantification reaction at the end of the polymer side chain, more preferably to have a group having a cinnamoyl structure or a group having a chalcone structure at the end of the polymer side chain, and a group having a cinnamoyl structure. It is more preferable to have it at the end of the polymer side chain. Such a photo-alignable polymer is, for example, a polymer having a structure represented by the following formula (A1′) and/or a structure represented by the formula (A1″) in a side chain (hereinafter collectively referred to as “photo-alignment (also referred to as "active polymer (A)").

［式（Ａ１’）および式（Ａ１’’）中、
ｋは、０または１を表す。
Ｌ^１は、単結合、または－Ｏ－を表す。
Ｌ^２は、単結合、－Ｏ－、－ＣＯＯ－、－ＯＣＯ－、－Ｎ＝Ｎ－、－ＣＨ＝ＣＨ－または－ＣＨ_２－を表す。
Ｒ^１、Ｒ^２およびＲ³は、それぞれ独立に、水素原子、ハロゲン原子、ハロゲン化アルキル基、ハロゲン化アルコキシ基、シアノ基、ニトロ基、アルキル基、アルコキシ基、アリール基、アリルオキシ基、アルコキシカルボニル基、カルボキシル基、スルホン酸基、アミノ基またはヒドロキシ基を表し、該カルボキシル基および該スルホン酸基はアルカリ金属イオンと塩を形成していてもよい。
Ｒ^４は、水素原子、アルキル基またはフェニル基を表す。
＊は、ポリマー主鎖に対する結合手を表す。］

[In formula (A1′) and formula (A1″),
k represents 0 or 1;
L ¹ represents a single bond or -O-.
L ² represents a single bond, -O-, -COO-, -OCO-, -N=N-, -CH=CH- or -CH ₂ -.
R ¹ , R ² and R ³ are each independently hydrogen atom, halogen atom, halogenated alkyl group, halogenated alkoxy group, cyano group, nitro group, alkyl group, alkoxy group, aryl group, allyloxy group, alkoxycarbonyl group, carboxyl group, sulfonic acid group, amino group or hydroxy group, and the carboxyl group and the sulfonic acid group may form a salt with an alkali metal ion.
^R4 represents a hydrogen atom, an alkyl group or a phenyl group.
* represents a bond to the polymer backbone. ]

In formulas (A1′) and (A1″), L ² is a single bond, —O—, —COO—, —OCO—, —N═N—, —C═C— and —CH ₂ — Either one facilitates the production of the photo-alignable polymer (A).

In formulas (A1′) and (A1″), R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, It is preferable because it is easy to form a photo-alignment film having good adhesion to the material, and it is easy to obtain a composition for a photo-alignment film having improved liquid stability. Examples of alkyl groups represented by R ¹ , R ² and R ³ include methyl group, ethyl group and butyl group, and examples of alkoxy groups include methoxy group, ethoxy group and butoxy group.

The main chain of the photo-alignable polymer (A) is not particularly limited, and the structure of the monomer unit forming the main chain is represented by, for example, formula (M-1) or formula (M-2) ( meth) acrylic acid ester unit; (meth) acrylamide unit represented by formula (M-3) or formula (M-4); vinyl ether unit represented by formula (M-5) or formula (M-6); Those selected from the group consisting of a methylstyrene unit represented by the formula (M-7) or the formula (M-8), and a vinyl ester unit represented by the formula (M-9) or the formula (M-10) is mentioned.
In formulas (M-1) to (M-10), * is a bond with the structure represented by formula (A1′) or formula (A″), or a bond with a spacer unit described later. show. In addition, in this specification, "the main chain of the photo-alignable polymer (A)" refers to the longest molecular chain among the molecular chains possessed by the photo-alignable polymer (A).

The main chain of the photo-orientable polymer (A) may be a homopolymer formed from one type of monomer unit or a copolymer formed from two or more types of monomer units. When the main chain of the photo-orientable polymer (A) is a copolymer, any of alternating, block, random, and graft bonding modes may be used.

Further, the structure of the monomer units forming the main chain of the photo-alignable polymer (A) is a silosesiloxane structure containing repeating units represented by the following formulas (M-11) to (M-16): good too. In formulas (M-11) to (M-16), * is a bond with the structure represented by formula (A1′) or formula (A1″), or a bond with a spacer unit described later. show.

In formulas (M-11) to (M-16), R ⁵ is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or is bonded to another silicon atom via an oxygen atom. Represents Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁵ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group and the like, and among them, methyl group and ethyl group. preferable. Examples of the alkoxy group having 1 to 6 carbon atoms represented by R ⁵ include methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butoxy group and the like. groups are preferred.

In formulas (M-13) and (M-14), Ph represents an optionally substituted divalent benzene ring (eg, phenylene group, etc.). In formula (M-16), Cy represents an optionally substituted divalent cyclohexane ring (eg, cyclohexane-1,4-diyl group, etc.).
n represents an integer of 1 to 4;

Among them, the main chain of the photo-alignable polymer (A) facilitates formation of a photo-alignment film having good adhesion to the substrate, and also facilitates obtaining a composition for a photo-alignment film having good liquid stability. , It is preferably composed of structural units represented by any of formulas (M-1) to (M-16), and represented by any of formulas (M-1) to (M-10) It is more preferably composed of structural units, and from structural units selected from the group consisting of (meth)acrylic acid ester units and (meth)acrylamide units represented by formulas (M-1) to (M-4) It is more preferable to configure Among all structural units constituting the main chain, for example, a polymer having the largest proportion of structural units selected from the group consisting of (meth)acrylic acid ester units and (meth)acrylamide units is referred to as "(meth)acrylic polymer ”. In other words, the photo-alignable polymer in the present invention is preferably a (meth)acrylic polymer.

The monomer structural unit forming the main chain of the photo-alignable polymer (A), as represented by any one of formulas (M-1) to (M-16), is represented by formula (A1′) or formula (A1 ''), or may be bonded via a linking group, which is an appropriate spacer unit. When bonding via a linking group, the linking group includes a carbonyloxy group (ester bond), an oxygen atom (ether bond), an imide group, a carbonylimino group (amide bond), and an iminocarbonylimino group (urethane bond). , an optionally substituted divalent aliphatic hydrocarbon group and an optionally substituted divalent aromatic hydrocarbon group, and a divalent group formed by combining these can be done. Specific examples of the divalent aromatic hydrocarbon group which may have a substituent include a phenylene group, a 2-methoxy-1,4-phenylene group, a 3-methoxy-1,4-phenylene group, a 2-ethoxy -1,4-phenylene group, 3-ethoxy-1,4-phenylene group, 2,3,5-trimethoxy-1,4-phenylene group and the like. Among these, the linking group is preferably an aliphatic hydrocarbon group, more preferably an optionally substituted alkanediyl group having 1 to 11 carbon atoms. Examples of such alkanediyl groups include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene and undecamethylene groups. , which may be linear or branched. Moreover, such an alkanediyl group may have a substituent. This substituent is, for example, an alkoxy group having 1 to 4 carbon atoms.

The structure represented by the formula (A1′) is a structural unit represented by the formula (A1-1) (hereinafter sometimes referred to as “structural unit (A1-1)′”), a photo-alignable polymer ( A), and in one embodiment of the present invention, the photo-orientable polymer (A) comprises the structural unit (A1-1). Further, the structure represented by the formula (A1'') is a structural unit represented by (A1-2) (hereinafter also referred to as "structural unit (A1-2)''") as a photo-alignable polymer (A) In one embodiment of the present invention, the photo-orientable polymer (A) contains structural units (A1-2).

In formulas (A1-1) and (A1-2), L ¹ , L ² , R ¹ , R ² , R ³ , R ⁴ and k are each represented by formula (A1′) or formula (A1″) ), SP ¹ is an optionally substituted alkanediyl group having 1 to 11 carbon atoms, and the structure represented by M ¹ is represented by formula (M-1) to formula It is a structure represented by any one of (M-16).

The photo-orientable polymer (A) may have a carboxyl group in addition to a photoreactive group, particularly a photoreactive group that undergoes a dimerization reaction. As one embodiment of the photo-alignable polymer (A) having a photoreactive group and a carboxyl group, it may be a polymer composed of the structural unit (A1-1), and as another embodiment, for example, In addition to the structure represented by formula (A1′), the structure represented by formula (A″) or structural unit (A1-1) and/or structural unit (A1-2), formula (A1-3) (hereinafter also referred to as “structural unit (A1-3)”).

In formula (A1-3), l represents 0 or 1, and SP ² represents an alkanediyl group having 1 to 11 carbon atoms which may have a substituent. Specific examples of SP ² are the same as the specific examples of SP ¹ in formulas (A1-1) and (A1-2), and the structure represented by M ² includes formulas (M-1) to (M -16).

In formula (A1-3), L ³ represents a single bond or -O-, L ⁴ represents a single bond, -O-, -COO-, -OCO-, -N=N-, -CH=CH - or -CH ₂ - is represented. R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. ^Examples of alkyl groups represented by R6 and ^R7 include methyl, ethyl and butyl groups, and examples of alkoxy groups include methoxy, ethoxy and butoxy groups.

When the photo-alignable polymer (A) comprises the structural unit (A1-1) or the structural unit (A1-2) and the structural unit (A1-3), all constituents of the photo-alignable polymer (A) When the molar fractions of the structural unit (A1-1), the structural unit (A1-2) and the structural unit (A1-3) to the structural unit are p, q and r respectively (p + r is 1 and q + r is 1 ), preferably satisfying the relationship 0.10<p or q≤0.90 and 0.10≤r<0.90. In the photo-alignable polymer comprising the structural unit (A1-1), the structural unit (A1-1) may be of one type or two or more types. Further, the photo-orientable polymer (A) is a structural unit (hereinafter referred to as " may be referred to as "another structural unit").

The photo-alignable polymer (A) is a monomer that induces the structural unit (A1-1) or the structural unit (A1-2), and optionally the structural unit (A1-3) and / or other structural units. It can be produced by (co)polymerizing the monomer to be used. As the method of (co)polymerization, a method conventionally known in the art may be adopted. For example, chain polymerization such as radical polymerization, anionic polymerization and cationic polymerization, and addition polymerization such as coordination polymerization may be adopted. . Polymerization conditions can be appropriately determined according to the type and amount of monomers used so as to obtain a photo-alignable polymer (A) having a desired molecular weight.

The weight average molecular weight (Mw) of the photo-alignable polymer (A) is preferably 10,000 or more, more preferably 15,000 or more, still more preferably 20,000 or more, and preferably 1,000,000 or less. More preferably 500,000 or less, still more preferably 250,000 or less. When the weight average molecular weight of the photo-alignable polymer (A) is at least the lower limit, it is easy to form a photo-alignment film with good adhesion to the substrate, and when the weight-average molecular weight is at most the upper limit, the photo-alignment film tend to be superior in handleability. The weight-average molecular weight can be adjusted, for example, by appropriately adjusting the type of structural unit of the photo-alignable polymer (A); It can be adjusted to the upper limit or less. The weight-average molecular weight of the photo-alignable polymer (A) can be determined, for example, by gel permeation chromatography (GPC) measurement and standard polystyrene conversion.

In the composition for forming a photo-alignment film, the polymer (A) may be used alone or in combination of two or more.

The content of the photo-alignment polymer in the composition for forming a photo-alignment film is not particularly limited as long as the concentration is such that the photo-alignment polymer can be completely dissolved in a solvent. On the other hand, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less. When the concentration of the photo-alignable polymer is at least the above lower limit, the resulting alignment film does not become too thin, and the adhesion to the substrate tends to increase. Moreover, when the concentration of the photo-orientable polymer is equal to or less than the above upper limit, the viscosity of the composition tends to be low, and unevenness in the thickness of the coating film of the composition tends to be less likely to occur. When two or more photo-alignment polymers are contained in the composition for forming a photo-alignment film, the content refers to the total content of the two or more photo-alignment polymers.

[Silane coupling agent]
As the silane coupling agent in the present invention, a compound known in the art can be used. Specifically, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane Silane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxy propyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropylethoxydimethylsilane and the like.

Also, the silane coupling agent may be of the silicone oligomer type. Silicone oligomers in the form of (monomeric) oligomers include, for example, 3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane. - copolymers containing mercaptopropyl groups such as tetramethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer; mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercapto Mercaptomethyl group-containing copolymers such as methyltriethoxysilane-tetramethoxysilane copolymer, mercaptomethyltriethoxysilane-tetraethoxysilane copolymer; 3-glydidoxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-glydidoxypropyl trimethoxysilane-tetraethoxysilane copolymer, 3-glydidoxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-glydidoxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-glydidoxypropylmethyldimethoxysilane-tetra Methoxysilane Copolymer, 3-Glydidoxypropylmethyldimethoxysilane-Tetraethoxysilane Copolymer, 3-Glydidoxypropylmethyldiethoxysilane-Tetramethoxysilane Copolymer, 3-Glydidoxypropylmethyldiethoxysilane-Tetraethoxysilane Copolymer 3-glydidoxypropyl group-containing copolymers such as; 3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane- Tetramethoxysilane Copolymer, 3-Methacryloyloxypropyltriethoxysilane-Tetraethoxysilane Copolymer, 3-Methacryloyloxypropylmethyldimethoxysilane-Tetramethoxysilane Copolymer, 3-Methacryloyloxypropylmethyldimethoxysilane-Tetraethoxysilane Copolymer, 3-Methacryloyl Oxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, 3-methacryloyl Copolymers containing methacryloyloxypropyl groups such as oxypropylmethyldiethoxysilane-tetraethoxysilane copolymer; 3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3 -acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane- Acryloyloxypropyl group-containing copolymers such as tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer; Methoxysilane Copolymer, Vinyltrimethoxysilane-Tetraethoxysilane Copolymer, Vinyltriethoxysilane-Tetramethoxysilane Copolymer, Vinyltriethoxysilane-Tetraethoxysilane Copolymer, Vinylmethyldimethoxysilane-Tetramethoxysilane Copolymer, Vinylmethyldimethoxysilane-Tetra Vinyl group-containing copolymers such as ethoxysilane copolymer, vinylmethyldiethoxysilane-tetramethoxysilane copolymer, vinylmethyldiethoxysilane-tetraethoxysilane copolymer; 3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyl trimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3- Amino group-containing copolymers such as aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer may be mentioned. can. Silane coupling agents may be used alone or in combination of two or more.

Among the above silane coupling agents, in the present invention, silane coupling agents having at least one functional group selected from the group consisting of primary amino groups, secondary amino groups and mercapto groups are preferred. Silane coupling agents having at least one functional group selected from the group consisting of amino groups and secondary amino groups are more preferred. By having at least one functional group selected from the group consisting of the functional groups described above, the silane coupling agent facilitates formation of a photo-alignment film having good adhesion to the substrate, and improved liquid stability. It tends to be a composition for forming a photo-alignment film having properties. In addition, the functional group may have an appropriate substituent or protective group in order to control the reactivity of the silane coupling agent. Examples of silane coupling agents having a protecting group include amino-protected type KBE-9103P (ketimine type) and X-12-1172ES (aldimine type) manufactured by Shin-Etsu Chemical Co., Ltd., and mercapto group-protected silane coupling agents. Protected forms include X-12-1056ES.

Among the silane coupling agents described above, 3-aminopropyltriethoxysilane and N-2-(aminoethyl)-3-aminopropyl are preferred because they facilitate the formation of a photo-alignment film with better adhesion to the substrate. methyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N -phenyl-3-aminopropyltrimethoxysilane is preferred. Commercially available compounds can also be used as such silane coupling agents, such as KBE-903, KBM-602, KBM-603, KBM-903, KBE-9103P, and KBM-573 (manufactured by Shin-Etsu Chemical Co., Ltd.). can be mentioned.

The silane coupling agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and still more preferably 2 parts by mass or more with respect to 100 parts by mass of the photo-alignable polymer in the composition for forming a photo-alignment film. , more preferably 3 parts by mass or more, preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 14 parts by mass or less. When the content of the silane coupling agent is at least the lower limit, it is easy to form a photo-alignment film having good adhesion to the substrate, and the composition for forming a photo-alignment film having improved liquid stability is likely to be obtained. . When the content of the silane coupling agent is equal to or less than the above upper limit, the orientation of the alignment film formed from the composition for forming a photo-alignment film after storage of the composition for forming a photo-alignment film tends to be good.

[acid]
In the present invention, the composition for forming a photo-alignment film contains an acid. The acid particularly contributes to improving the liquid stability of the composition for forming a photo-alignment film. In the present invention, the acid may be organic acid or inorganic acid. Examples of inorganic acids include acids derived from hydrogen halides (eg, hydrochloric acid, hydrobromic acid, etc.), acids derived from halogen oxo acids (eg, hypochlorous acid, chlorous acid, perchloric acid, hypobromous acid , bromous acid, perbromic acid, etc.), sulfuric acid, nitric acid, phosphoric acid, hexafluorophosphoric acid, chromic acid, boric acid and the like. Examples of organic acids include glycolic acid, carboxylic acid (acetic acid, citric acid, formic acid, gluconic acid, lactic acid, oxalic acid, tartaric acid, etc.), sulfonic acid (methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, etc.). , acrylic acid, methacrylic acid, and the like. An acid may be used individually by 1 type, and may be used in combination of 2 or more type.

In a preferred embodiment of the present invention, the acid has an acid dissociation constant (pKa) of preferably 5.0 or less, more preferably 4.5 or less, even more preferably 4.0 or less. When the pKa of the acid is equal to or less than the above upper limit, it is easy to form a photo-alignment film having good adhesion to the substrate, and the composition for forming a photo-alignment film having improved liquid stability is likely to be obtained. Although the lower limit of pKa is not particularly limited, it is preferably -5.0 or higher, more preferably -4.0 or higher, and still more preferably -3.0 or higher. When the pKa of the acid is equal to or higher than the lower limit, it is easy to suppress acid corrosion of manufacturing equipment. The pKa of an acid can be obtained from materials such as "Kagaku Binran" (The Chemical Society of Japan). When the composition for forming a photo-alignment film contains two or more acids, at least one preferably satisfies the above pKa.

In the present invention, the boiling point of the acid is preferably 70° C. or higher, more preferably 80° C. or higher, still more preferably 90° C. or higher, and preferably 150° C. or lower, more preferably 140° C. or lower. When the boiling point of the acid is at least the lower limit, it is easy to form a photo-alignment film having good adhesion to the substrate, and the composition for forming a photo-alignment film having improved liquid stability is likely to be obtained, and the boiling point of the acid is less than or equal to the upper limit, the residual amount of acid in the photo-alignment film can be easily reduced. The boiling points of acids can be obtained from materials such as "Kagaku Binran" (The Chemical Society of Japan). When the composition for forming a photo-alignment film contains two or more acids, at least one preferably satisfies the above boiling point.

A preferred specific example of the acid in the present invention is formic acid, since it facilitates the formation of a photo-alignment film having good adhesion to the substrate and a composition for forming a photo-alignment film having improved liquid stability. , toluenesulfonic acid, acrylic acid and acetic acid.

In the present invention, the molar ratio of the acid and the silane coupling agent (acid [mol]/silane coupling agent [mol]) is preferably 1 or more, more preferably 2 or more, still more preferably 6 or more, and still more It is preferably 15 or more, preferably 100 or less, more preferably 60 or less, still more preferably 50 or less. When the molar ratio of the acid and the silane coupling agent is at least the above lower limit, the composition for forming a photo-alignment film easily forms a photo-alignment film with good adhesion to the substrate and has improved liquid stability. easy to become. In addition, the alignment of the alignment film formed from the composition for forming a photo-alignment film tends to be good. When the molar ratio of the acid and the silane coupling agent is equal to or less than the upper limit, it is easy to reduce the residual amount of the acid in the photo-alignment film.

According to studies by the present inventors, conventional photo-alignment can be achieved by adding a specific acid, particularly an acid having a specific pKa, to a composition for forming a photo-alignment film containing a photo-alignment polymer, a silane coupling agent and a solvent. It has been found that the liquid stability of the film-forming composition can be more easily improved. Although the reason for this is not clear, it is presumed that the addition of a specific acid enhances the effect of suppressing side reactions in the composition that impair the liquid stability of the composition for forming a photo-alignment film.

[solvent]
In the composition for forming a photo-alignment film of the present invention, the solvent is not particularly limited as long as it is a solvent capable of dissolving the components contained in the composition for forming a photo-alignment film, and specifically water; methanol, ethanol. , ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve and propylene glycol monomethyl ether; ester solvents; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; aromatic hydrocarbon solvents such as toluene and xylene; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorinated hydrocarbon solvents such as chloroform and chlorobenzene; and the like. These solvents may be used alone or in combination of two or more.

[Other ingredients]
In the present invention, the composition for forming a photo-alignment film may contain, in addition to the components described above, any component within a range that does not significantly impair the properties of the photo-alignment film. Examples of such optional components include polymeric materials, photosensitizers, and the like.

By using a polymer material, the solution properties of the composition for forming a photo-alignment film can be improved. Examples of such polymeric materials include polyvinyl alcohol, polyimide, cellulose derivatives, and the like. One type of polymeric material may be used alone, or two or more types may be used in combination. The content of the polymer material in the composition for forming a photo-alignment film (the total amount when multiple types are included) is usually 0.1 to 10 parts by mass with respect to 100 parts by mass of the photo-alignable polymer, preferably 1 to 8 parts by mass. When the content of the polymeric material is within the above range, a composition having excellent coatability can be obtained.

A photosensitizer can improve the film strength of the photo-alignment film. Examples of photosensitizers include xanthone compounds such as xanthone or thioxanthone (eg, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.), anthracene compounds having substituents such as anthracene or alkyl ethers (eg, dibutoxyanthracene etc.), phenothiazine or rubrene. The photosensitizers may be used singly or in combination of two or more.

When the composition for forming a photo-alignment film contains a photosensitizer, its content (the total amount when it contains a plurality of types) is preferably 0.1 to 30 with respect to 100 parts by mass of the photo-alignable polymer. parts by mass, more preferably 0.3 to 10 parts by mass, and even more preferably 0.5 to 8.0 parts by mass. When the content of the photosensitizer is within the above range, a composition having improved film strength can be obtained.

The composition for forming a photo-alignment film can be produced by a conventionally known preparation method, and usually can be prepared by mixing and stirring the above components.

The viscosity of the composition for forming a photo-alignment film is preferably 0.1 to 50 mPa·s, more preferably 0.5 to 40 mPa·s, still more preferably 1 to 30 mPa·s. When the viscosity of the composition for forming a photo-alignment film is within the above range, the composition is excellent in handleability and coatability, and the thickness of the obtained photo-alignment film can be easily made uniform.

[Photo-alignment film]
The present invention includes a photo-alignment film which is a cured product of the composition for forming a photo-alignment film of the present invention, and a laminate comprising the photo-alignment film and a substrate. In the present invention, the photo-alignment film is formed, for example, by applying a composition for forming a photo-alignment film to a surface of a substrate or the like on which a photo-alignment film is to be formed, drying the solvent, and then irradiating with polarized light (preferably polarized UV). Obtainable. In the present invention, the photo-alignment film and the substrate may be laminated via another layer (for example, a primer layer), but as one aspect of the present invention, the photo-alignment film and the substrate are adjacent to each other. is preferred.

In the present invention, the substrate preferably has a polar group. Here, in the present specification, that the substrate has a polar group means that the polar group is present in the substrate before the alignment film is formed on the substrate. Polar groups include, for example, hydroxyl groups, carboxyl groups, and amino groups. Among them, from the viewpoint of reactivity with the silane coupling agent, hydroxyl groups, carboxyl groups, and amino groups, which are easily introduced into the base material surface by surface modification treatment of the base material, or as a material constituting the base material. It preferably has at least one polar group selected from the group, and more preferably has a hydroxyl group. Since the substrate before forming the alignment film has the polar group, a bond originating from the reaction between the polar group present in the substrate and the silicon of the silane coupling agent forming the alignment film is generated, and the substrate The adhesiveness between the material and the alignment film tends to be good. Therefore, in one embodiment of the present invention, between the substrate and the alignment film constituting the laminate of the present invention, the polar group (existing in the substrate) and the silicon (having the silane coupling agent) There may be Si—O bonds originating from the reaction.

The polar group is preferably present on the substrate surface on which the alignment film is laminated. Such a substrate may be a substrate obtained by forming a film of a resin having a polar group such as a vinyl alcohol resin or a cellulose resin as a material, or a precursor of the polar group. After forming a film (precursor film) from a material having a group, the precursor group contained in the precursor film may be modified into a polar group. Such modification includes, for example, plasma treatment, laser treatment, ozone treatment, saponification treatment or flame treatment under vacuum or atmospheric pressure. Further, it may be a substrate having a polymer having a polar group attached to the surface of the substrate made of a material that does not have a polar group or its precursor group, or a substrate having a polymer having a polar group precursor attached to the surface of the substrate. It may also be a base material modified on the base. Furthermore, a graft polymerization in which a monomer having a polar group or a polymer having a polar group is attached to the surface of a substrate made of a material that does not have a polar group or its precursor group, and then reacted by irradiation with radiation, plasma, ultraviolet rays, etc. It may be obtained by the method of Examples of the method of attaching a polymer having a polar group or a precursor group of a polar group, or a monomer to the substrate surface include a method of applying a solution in which the polymer or monomer is dissolved to the substrate surface.

Before or after the modification treatment and the treatment of adhering a polar group or a polymer having a polar group precursor group, or a monomer to the substrate surface, the substrate described above further improves the adhesion between the substrate surface and the alignment film. In order to improve the quality, the surface on which the alignment film is to be laminated may be subjected to a known pretreatment. Examples of such pretreatment include corona treatment, plasma treatment, flame treatment, primer treatment, and the like. Specific methods and conditions for each treatment can be appropriately selected from methods and conditions known in the art according to the intended use or properties of the laminate.

The film thickness of the substrate is preferably 1 μm or more, more preferably 1.5 μm or more, and preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. When the film thickness of the base material is at least the above lower limit, the workability tends to be excellent, and when the film thickness of the base material is at most the above upper limit, it is easy to achieve a thin laminate. The film thickness of the substrate can be measured using, for example, a laser microscope, a stylus film thickness meter, or the like.

In the present invention, the laminate is prepared by, for example, applying the composition for forming a photo-alignment film of the present invention on a substrate, removing the solvent contained in the composition, and removing the solvent from the photo-alignment film. It can be obtained by a method comprising curing a forming composition.

Examples of the method for applying the composition for forming a photo-alignment film onto a substrate include coating methods such as a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, an applicator method, and a flexographic method. A known method such as a printing method can be used.

Methods for removing the solvent by drying include natural drying, ventilation drying, heat drying, and reduced pressure drying. This forms a dry coating film.
The drying temperature may be, for example, 50 to 200°C, preferably 100°C or higher, more preferably 110°C or higher, still more preferably 120°C or higher, and preferably 150°C or lower. When the drying temperature is within the above range, the solvent can be removed efficiently. In addition, the effect of temperature on the photo-alignment film can be suppressed, and the deterioration of the liquid crystal alignment ability exhibited by the photo-alignment film is less likely to occur. The drying time is preferably 20 seconds to 10 minutes, more preferably 30 seconds to 5 minutes.

Examples of the method for curing the composition for forming a photo-alignment film include polarized irradiation (preferably polarized UV irradiation). The photo-alignment film can arbitrarily control the direction of the alignment regulating force by selecting the polarization direction of the polarized light to be irradiated.

As a method of irradiating polarized light, the dry coating film obtained by removing the solvent from the composition for forming a photo-alignment film may be directly irradiated with polarized light. A format in which polarized light is transmitted and irradiated may be used. Moreover, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range in which the photoreactive groups of the photo-alignment film-forming polymer can absorb the light energy. Specifically, UV (ultraviolet light) with a wavelength in the range of 250 to 400 nm is particularly preferred.

Light sources used for the polarized irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and ultraviolet light lasers such as KrF and ArF. High-pressure mercury lamps, ultra-high-pressure mercury lamps and metal halide lamps are more preferred. preferable. These lamps are preferable because of their high emission intensity of ultraviolet light with a wavelength of 313 nm. Polarized light can be emitted by passing the light from the light source through a suitable polarizer. As such a polarizer, a polarizing filter, a polarizing prism such as Glan-Thompson or Glan-Taylor, and a wire grid type polarizer can be used.

In the present invention, the thickness (film thickness) of the photo-alignment film is preferably 10 nm or more, more preferably 20 nm or more, and preferably 1000 nm or less, more preferably 500 nm or less. If the thickness of the photo-alignment film is above the lower limit, a sufficient alignment regulating force cannot be obtained, and if the thickness of the photo-alignment film is below the above upper limit, the film can be made thinner. The thickness of the photo-alignment film can be measured using, for example, a laser microscope, a stylus film thickness meter, or the like.

The invention further includes a polarizing element comprising a substrate, the photo-alignment film of the invention and a polarizing film.

In the present invention, the polarizing film is not particularly limited, but for example, by orienting iodine, dichroic dye, or the like in polyvinyl alcohol (PVA) resin or aligned liquid crystal, polarized light absorption selectivity is imparted. Mention may be made of membranes (films).

The iodine-PVA polarizing film can be produced, for example, by a sequential stretching method in which PVA in the form of a film is stretched in a heated state and then dyed with iodine and cross-linked with boric acid, or while being dyed with iodine and cross-linked with boric acid in water. It can be produced by a simultaneous stretching method in which PVA in film form is stretched. At this time, the draw ratio is preferably 4 to 8 times, and the PVA film is prepared by continuously immersing the PVA film in an iodine aqueous solution and a boric acid aqueous solution to impregnate each molecule. By drying the PVA film after dyeing, water is removed and the boric acid cross-linking proceeds to obtain a PVA polarizing film. As a drying method at this time, it is preferable to carry out by ventilation drying method or infrared drying method, and the temperature is preferably in the range of 40°C to 150°C, more preferably 60°C to 130°C.

A polarizing film in which a dichroic dye is oriented in a liquid crystal can be produced, for example, by mixing a dichroic dye in advance in a layer composed of a polymer in an oriented state of a polymerizable liquid crystal compound. .

Examples of the polymerizable liquid crystal compound include compounds represented by the following formula (I) (hereinafter sometimes referred to as "compound (I)").These polymerizable liquid crystal compounds may be used alone. It is good, and you may combine two or more types.
U ¹ -V ¹ -W ¹ -X ¹ -Y ¹ -X ² -Y ² -X ³ -W ² -V ^A -U ² (I)
[in the formula (I),
X ¹ , X ² and X ³ each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein the divalent aromatic group or divalent alicyclic A hydrogen atom contained in the hydrocarbon group is substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group. A carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom. provided that at least one of X ¹ , X ² and X ³ is an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane-1,4-diyl group is.
Y ¹ , Y ² , W ¹ and W ² are each independently a single bond or a divalent linking group.
V ¹ and V ² each independently represent an optionally substituted alkanediyl group having 1 to 20 carbon atoms, and —CH ₂ — constituting the alkanediyl group is —O—, — It may be replaced with S- or -NH-.
U ¹ and U ² independently of each other represent a polymerizable group or a hydrogen atom, at least one of which is a polymerizable group. ]

In compound (I), at least one of X ¹ , X ² and X ³ is an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane- It is a 1,4-diyl group. In particular, X ¹ and X ³ are preferably optionally substituted cyclohexane-1,4-diyl groups, and the cyclohexane-1,4-diyl groups are trans-cyclohexane- A 1,4-diyl group is more preferred. When it contains a trans-cyclohexane-1,4-diyl group structure, it tends to exhibit smectic liquid crystallinity. Further, optionally substituted 1,4-phenylene group or optionally substituted cyclohexane-1,4-diyl group optionally has a methyl group , an alkyl group having 1 to 4 carbon atoms such as an ethyl group and a butyl group, a cyano group and a halogen atom such as a chlorine atom and a fluorine atom. It is preferably unsubstituted.

Y ¹ and Y ² are each independently a single bond, -CH ₂ CH ₂ -, -CH ₂ O-, -COO-, -OCO-, -N=N-, -CR ^a =CR ^b -, - C≡C— or —CR ^a =N— is preferred, and R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y ¹ and Y ² are more preferably -CH ₂ CH ₂ -, -COO-, -OCO- or a single bond, and more preferably Y ¹ and Y ² have different bonding schemes. When Y ¹ and Y ² have different bonding schemes, smectic liquid crystallinity tends to occur.

W ¹ and W ² are each independently preferably a single bond, —O—, —S—, —COO— or —OCO—, and are more preferably each independently a single bond or —O—.

The alkanediyl groups having 1 to 20 carbon atoms represented by V ¹ and V ² include methylene group, ethylene group, propane-1,3-diyl group, butane-1,3-diyl group, butane-1,4 -diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, decane-1,10-diyl group, tetradecane -1,14-diyl group and icosane-1,20-diyl group. V ¹ and V ² are preferably C 2-12 alkanediyl groups, more preferably straight-chain C 6-12 alkanediyl groups. The straight-chain alkanediyl group having 6 to 12 carbon atoms improves crystallinity and tends to exhibit smectic liquid crystallinity.
Examples of substituents optionally possessed by the optionally substituted alkanediyl group having 1 to 20 carbon atoms include a cyano group and a halogen atom such as a chlorine atom and a fluorine atom, and the alkanediyl group is , is preferably unsubstituted, and more preferably an unsubstituted and linear alkanediyl group.

Both U ¹ and U ² are preferably polymerizable groups, more preferably photopolymerizable groups. A polymerizable liquid crystal compound having a photopolymerizable group is advantageous in that it can be polymerized under lower temperature conditions.

^The polymerizable groups represented by U1 and U2 may be different from ^each other, but are preferably the same. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group and oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyloxy group is more preferred.

Specific examples of the polymerizable liquid crystal compound (I) are described, for example, in JP-A-2017-167517; for example, Lub et al., Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), or a known method described in Japanese Patent No. 4,719,156.

A dichroic dye means a dye having a property that the absorbance in the long axis direction and the absorbance in the short axis direction of the molecule are different. The dichroic dye that can be used in the present invention is not particularly limited as long as it has the properties described above, and may be a dye or a pigment. Also, two or more dyes or pigments may be used in combination, or a dye and a pigment may be used in combination. Moreover, the dichroic dye may have polymerizability or may have liquid crystallinity.

In one aspect of the present invention, the dichroic dye preferably has a maximum absorption wavelength (λ _MAX ) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes and anthraquinone dyes. Among them, azo dyes have high linearity and are suitable for producing a polarizing film having excellent polarizing performance. Therefore, in one aspect of the invention, the dichroic dye is preferably an azo dye.

Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakis azo dyes and stilbenazo dyes, with bisazo dyes and trisazo dyes being preferred. Examples of such azo dyes include compounds represented by formula (II).
K ¹ (-N=N-K ² ) _p -N=N-K ³ (II)
[In formula (II), K ¹ and K ³ are, independently of each other, an optionally substituted phenyl group, an optionally substituted naphthyl group, or an optionally substituted represents a good monovalent heterocyclic group. K ² is a p-phenylene group optionally having substituents, a naphthalene-1,4-diyl group optionally having substituents or a divalent heterocyclic ring optionally having substituents represents a group. p represents an integer of 1 to 4; When p is an integer of ² or more, multiple K2 may be the same or different. -N=N-bonds may be replaced with -C=C-, -COO-, -NHCO- and -N=CH-bonds within the range of absorption in the visible region. ]

In formula (II), the monovalent heterocyclic group includes, for example, a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole from which one hydrogen atom has been removed. groups. The divalent heterocyclic group includes a group obtained by removing two hydrogen atoms from the above heterocyclic compound.

A phenyl group, a naphthyl group and a monovalent heterocyclic group for K ¹ and K ³ in formula (II), and a p-phenylene group, a naphthalene-1,4-diyl group and a divalent heterocyclic group for K ² are Optional substituents include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms having a polymerizable group, an alkenyl group having 1 to 4 carbon atoms; a methoxy group, an ethoxy group, a butoxy group, and the like. alkoxy group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms having a polymerizable group; fluorinated alkyl group having 1 to 4 carbon atoms such as trifluoromethyl group; cyano group; nitro group; halogen atom; amino group, diethylamino group, substituted or unsubstituted amino group such as pyrrolidino group (substituted amino group means an amino group having one or two alkyl groups having 1 to 6 carbon atoms, an amino group having 1 to 6 carbon atoms having a polymerizable group, or an amino group in which two substituted alkyl groups are bonded together to form an alkanediyl group having 2 to 8 carbon atoms. NH _2. ) and the like. Examples of the polymerizable group include an acryloyl group, a methacryloyl group, an acryloyloxy group, and a methacryloyloxy group.

Specific examples of the azo dyes represented by formula (II) include compounds represented by any one of the following formulas (II-1) to (II-8). These azo dyes may be used alone or in combination of two or more.

［式（ＩＩ－１）～（ＩＩ－８）中、
Ｂ^１～Ｂ^３０は、互いに独立して、水素原子、炭素数１～６のアルキル基、炭素数１～６のアルケニル基、炭素数１～４のアルコキシ基、シアノ基、ニトロ基、置換または無置換のアミノ基（置換アミノ基および無置換アミノ基の定義は前記のとおり）、塩素原子またはトリフルオロメチル基を表わす。
ｎ１～ｎ４は、互いに独立に０～３の整数を表わす。
ｎ１が２以上である場合、複数のＢ^２は互いに同一でも異なっていてもよく、
ｎ２が２以上である場合、複数のＢ^６は互いに同一でも異なっていてもよく、
ｎ３が２以上である場合、複数のＢ^９は互いに同一でも異なっていてもよく、
ｎ４が２以上である場合、複数のＢ^１４は互いに同一でも異なっていてもよい。］

[In the formulas (II-1) to (II-8),
B ¹ to B ³⁰ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, substituted or represents an unsubstituted amino group (the definitions of substituted amino group and unsubstituted amino group are as described above), chlorine atom or trifluoromethyl group;
n1 to n4 each independently represents an integer of 0 to 3;
When n1 is ² or more, the plurality of B2 may be the same or different,
When n2 is 2 or more, the plurality of ^B6 may be the same or different,
When n3 is ² or more, multiple B9 may be the same or different,
When n4 is 2 or more, the plurality of ^B14 may be the same or different. ]

In the present invention, the polarizing element can be produced, for example, by the following method. A composition containing a polymerizable liquid crystal compound and a dichroic dye, optionally diluted with a solvent, on the alignment film formed on the base material by the above-described method (hereinafter referred to as "polarizing film-forming composition" ) is applied. Next, if necessary, the solvent is dried and then polymerized to obtain a polymer of the polymerizable liquid crystal compound in the aligned state of the mixture containing the polymerizable liquid crystal compound and the dichroic dye. By polymerizing the polymerizable liquid crystal compound while maintaining the horizontally aligned state of the polymerizable liquid crystal compound and the dichroic dye, a cured liquid crystal film maintaining the aligned state is obtained, and the cured liquid crystal film is a polarizing film. to provide a polarizing element including a substrate, an alignment film and a polarizing film. The polarizing film-forming composition may contain components such as a solvent, a polymerization initiator, a photosensitizer, a leveling agent, and a reactive additive. As for the preparation of the composition for forming a polarizing film and the method of applying the same, the methods mentioned in the preparation of the alignment film and the method of applying the same can be similarly exemplified.

The content of the polymerizable liquid crystal compound in the composition for forming a polarizing film (the total amount when multiple types are included) is, from the viewpoint of exhibiting liquid crystallinity, relative to 100 parts by mass of the solid content of the composition for forming a polarizing film, It is usually 60 to 99 parts by mass, preferably 70 to 95 parts by mass, more preferably 75 to 90 parts by mass. In addition, the content of the dichroic dye (the total amount thereof when a plurality of types are included) is usually 1 per 100 parts by mass of the solid content of the composition for forming a polarizing film, from the viewpoint of obtaining good light absorption characteristics. It is up to 30 parts by mass, preferably 2 to 20 parts by mass, more preferably 3 to 15 parts by mass. The term "solid content" as used herein refers to the total amount of components of the polarizing film-forming composition excluding the solvent.

The solvent used in the polarizing film-forming composition can be appropriately selected according to the solubility of the polymerizable liquid crystal compound and the dichroic dye used. Specific examples include the same solvents as those previously exemplified as the solvent that can be used for the alignment film-forming composition. As the solvent, only one type may be used alone, or two or more types may be used in combination. The content of the solvent is preferably 100 to 1,900 parts by mass, more preferably 150 to 900 parts by mass, based on 100 parts by mass of the solid content of the composition for forming a polarizing film.

The polymerization initiator used in the polarizing film-forming composition is a compound capable of initiating the polymerization reaction of the polymerizable liquid crystal compound, and is preferably a photopolymerization initiator in that the polymerization reaction can be initiated under lower temperature conditions. Specifically, photopolymerization initiators capable of generating active radicals or acids by the action of light may be mentioned, and among these, photopolymerization initiators capable of generating radicals by the action of light are preferred. A polymerization initiator can be used individually or in combination of 2 or more types.

As the photopolymerization initiator, known photopolymerization initiators can be used. For example, photopolymerization initiators that generate active radicals include self-cleavage photopolymerization initiators and hydrogen abstraction photopolymerization initiators. There is
Self-cleavage photopolymerization initiators include self-cleavage benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. Available. In addition, as a hydrogen abstraction type photopolymerization initiator, hydrogen abstraction type benzophenone compounds, benzoin ether compounds, benzyl ketal compounds, dibenzosuberone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, halogenoacetophenone compounds. compounds, dialkoxyacetophenone-based compounds, halogenobisimidazole-based compounds, halogenotriazine-based compounds, triazine-based compounds, and the like can be used.
As photopolymerization initiators that generate acid, iodonium salts, sulfonium salts, and the like can be used.

Among these, a reaction at a low temperature is preferable from the viewpoint of preventing dissolution of the dye, and a self-cleavage photopolymerization initiator is preferable from the viewpoint of reaction efficiency at a low temperature. compounds and oxime ester compounds are preferred.

The content of the polymerization initiator in the polarizing film-forming composition is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound.

Examples of the photosensitizer used in the polarizing film-forming composition include those exemplified above as the photosensitizer that can be used in the alignment film-forming composition. Only one photosensitizer may be used alone, or two or more photosensitizers may be used in combination. The content of the photosensitizer is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound.

The leveling agent used in the composition for forming a polarizing film has the function of adjusting the fluidity of the composition for forming a polarizing film and making the coating film obtained by applying the composition for forming a polarizing film more flat. , specifically surfactants. The leveling agent is preferably at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. A leveling agent can be used individually or in combination of 2 or more types.

When the polarizing film-forming composition contains a leveling agent, the content thereof is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. .

The reactive additive used in the composition for forming a polarizing film can generally improve the adhesion of the polarizing film. The reactive additive preferably has a carbon-carbon unsaturated bond and an active hydrogen reactive group in its molecule. The term "active hydrogen-reactive group" as used herein refers to a group having reactivity with groups having active hydrogen, such as a carboxy group (--COOH), a hydroxyl group (--OH), and an amino group (--NH ₂ ). Representative examples thereof include a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, a maleic anhydride group, and the like. The number of carbon-carbon unsaturated bonds and active hydrogen reactive groups in the reactive additive is usually 1 to 20 each, preferably 1 to 10 each.

At least two active hydrogen-reactive groups are preferably present in the reactive additive, and in this case, the multiple active hydrogen-reactive groups may be the same or different.

The carbon-carbon unsaturated bond possessed by the reactive additive may be a carbon-carbon double bond or a carbon-carbon triple bond, or a combination thereof, preferably a carbon-carbon double bond. Among them, the reactive additive preferably contains a carbon-carbon unsaturated bond as a vinyl group and/or (meth)acrylic group. Furthermore, a reactive additive in which the active hydrogen reactive group is at least one selected from the group consisting of an epoxy group, a glycidyl group and an isocyanate group is preferred, and a reactive additive having an acrylic group and an isocyanate group is more preferred. .

Specific examples of reactive additives include compounds having a (meth)acrylic group and an epoxy group, such as methacryloxyglycidyl ether and acryloxyglycidyl ether; compounds having a group; compounds having a (meth)acrylic group and a lactone group, such as lactone acrylate and lactone methacrylate; compounds having a vinyl group and an oxazoline group, such as vinyloxazoline and isopropenyloxazoline; isocyanatomethyl acrylate , isocyanatomethyl methacrylate, 2-isocyanatoethyl acrylate and 2-isocyanatoethyl methacrylate, oligomers of compounds having (meth)acrylic groups and isocyanate groups. Also included are compounds having a vinyl group or vinylene group and an acid anhydride, such as methacrylic anhydride, acrylic anhydride, maleic anhydride and vinyl maleic anhydride. Among them, methacryloxyglycidyl ether, acryloxyglycidyl ether, isocyanatomethyl acrylate, isocyanatomethyl methacrylate, vinyloxazoline, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate and the above oligomers are preferred, isocyanatomethyl acrylate, 2-Isocyanatoethyl acrylate and the above oligomers are particularly preferred.

When the polarizing film-forming composition contains a reactive additive, the content of the reactive additive is usually 0.01 to 10 parts by mass, preferably 0, per 100 parts by mass of the polymerizable liquid crystal compound. .1 to 5 parts by mass.

A polarizing film is formed by polymerizing a liquid crystalline substance while maintaining a liquid crystalline state. A polymerization method may be appropriately selected from a photopolymerization method, a thermal polymerization method, and the like, depending on the type of the polymerizable group. In one embodiment of the present invention, the photopolymerization method is preferable as the polymerization method because polymerization can be performed at a low temperature and industrial production is easy when the polymerization is performed by a photopolymerization method. In photopolymerization, the light irradiated to the dry coating film includes the type of the polymerizable liquid crystal compound contained in the dry coating film (especially the type of the polymerizable group possessed by the polymerizable liquid crystal compound, etc.), the type of the polymerization initiator, It is appropriately selected according to the type and amount thereof. Specific examples thereof include one or more active energy rays selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays and γ-rays, and active electron beams. Among them, ultraviolet light is preferable in that the progress of the polymerization reaction can be easily controlled and that a widely used photopolymerization apparatus in the field can be used. It is preferable to select the types of the polymerizable liquid crystal compound and the polymerization initiator contained in the polarizing film-forming composition. The polymerization temperature can also be controlled by irradiating light while cooling the dry coating film with an appropriate cooling means during polymerization. A patterned polarizing film can also be obtained by performing masking and development during photopolymerization.

Examples of the light source of the active energy ray include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, and wavelength ranges. LED light sources, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, etc., which emit light in the range of 380 to 440 nm can be used.

The UV irradiation intensity is usually 10 to 3,000 mW/cm ² . The ultraviolet irradiation intensity is preferably in the wavelength range effective for activation of the polymerization initiator. The light irradiation time is usually 0.1 second to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, still more preferably 10 seconds to 1 minute. When irradiated once or multiple times with such an irradiation intensity of ultraviolet rays, the cumulative amount of light is 10 to 3,000 mJ/cm ² , preferably 50 to 2,000 mJ/cm ² , more preferably 100 to 1,000 mJ/cm. ² .

The thickness of the polarizing element including the base material, the alignment film and the polarizing film (preferably the polarizing element comprising the base material, the alignment film and the polarizing film) can be appropriately determined according to the use of the optical laminate incorporating the polarizing element. , preferably 1 μm or more, more preferably 2 μm or more, and preferably 10 μm or less, more preferably 9 μm or less. When the thickness of the polarizing element is within the above range, it can be easily made ultra-thin. The thickness of the polarizing element can be measured using an interference film thickness meter, a laser microscope, a stylus film thickness meter, or the like.

A photo-alignment film having a desired alignment control force can be produced from the composition for forming a photo-alignment film of the present invention. It is possible to align the liquid crystal in a direction. Therefore, on the photo-alignment film formed from the composition for forming a photo-alignment film of the present invention, for example, a retardation film formed by polymerizing a polymerizable liquid crystal compound can be formed in place of the polarizing film.

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" in the examples mean % by mass and parts by mass, respectively.

(1) Preparation Synthesis Example 1 of Composition for Forming Photo-Alignment Film: Synthesis of Photo-Orientation Polymer 1 Photo-orientation polymer 1 consists of the following structural units.
[Photo-orientable polymer 1]

[Synthesis scheme of photo-alignable polymer 1]

[Synthesis of compound (a1-1-1)]
50 g (258 mmol) of ferulic acid was dissolved in 360 g of methanol. To the resulting solution, 10 g of sulfuric acid was added at room temperature, the temperature was raised until the solvent was refluxed, and the reaction was allowed to proceed for 2 hours under reflux. After cooling the resulting reaction solution, 150 g of ice and 150 g of water were added. The supernatant was removed by decantation, and 150 g of water at 5° C. was added to crystallize. The resulting white crystals were filtered. The filtered white crystals were further washed with a 1M aqueous sodium hydrogencarbonate solution and water, and then vacuum dried to obtain 22.2 g of compound (a1-1-1). Yield was 83% based on ferulic acid.

[Synthesis of compound (b1-1-1)]
25 g (120 mmol) of compound (a1-1-1) was dissolved in 250 g of dimethylacetamide. 33.19 g (240 mmol) of potassium carbonate and 1.99 g (12 mmol) of potassium iodide were added to the resulting solution. 6-Chlorohexanol was added dropwise to the obtained dispersion, and after stirring at room temperature for 1 hour, the mixture was stirred at 70° C. for 8 hours. The resulting reaction solution was filtered to remove insolubles. 200 g of methyl isobutyl ketone and 300 g of water were added to the filtrate, and the mixture was stirred, allowed to stand, and separated to recover an organic layer. 200 g of water was added to the recovered organic layer, and the washing operation of stirring, standing, and liquid separation was repeated twice. The solvent was removed from the recovered organic layer by distillation under reduced pressure using an evaporator to obtain a crude product of compound (b1-1-1).

[Synthesis of compound (c1-1-1)]
The entire crude product of compound (b1-1-1) was dissolved in 185 g of ethanol. 92 g of water and 14.41 g (360 mmol) of sodium hydroxide were added to the resulting solution and stirred at 80° C. for 1 hour. After cooling the reaction solution to about 3°C, the pH was adjusted to 2 by adding 2M hydrochloric acid aqueous solution while keeping the temperature at 5°C or lower. The acid precipitated white precipitate was collected by filtration, washed twice with a mixed solution of 100 g of water and 80 g of methanol, and then vacuum dried to obtain 30.4 g of compound (c1-1-1). The yield was 86% based on compound (a1-1-1).

[Synthesis of compound (M1-1-1)]
27.46 g (93 mmol) of compound (c1-1-1) was dissolved in 280 g of chloroform. To the resulting solution, 2.06 g of BHT (di-t-butyl-hydroxytoluene) and 37.73 g (373 mmol) of triethylamine were added as polymerization inhibitors, and the mixture was stirred under ice cooling. 29.26 g (260 mmol) of methacrylic acid chloride was added dropwise to the reaction solution, and the mixture was stirred for 5 hours while maintaining the temperature below 5°C. 5.7 g of dimethylaminopyridine and 190 g of water were added to the obtained reaction solution, and the mixture was stirred at room temperature for 12 hours. After allowing to stand, the organic layer was recovered, 100 g of a 2N hydrochloric acid aqueous solution was added to this organic layer, and a series of washing operations of stirring, standing and liquid separation was repeated twice. The organic layer was recovered, 300 g of n-heptane was added, and the precipitated crystals were collected by filtration. After washing twice with a mixed solvent of 100 g of water and 80 g of methanol, it was dried under vacuum to obtain 22.0 g of compound (M1-1-1). The yield was 65% based on compound (c1-1-1).

[Synthesis of photo-alignable polymer 1]
1.00 g (2.76 mmol) of the compound (M1-1-1) and 10 g of tetrahydrofuran were added to a Schlenk tube, and after deoxygenation, 2.27 mg of azobisisobutyronitrile (AIBN) was added while flowing nitrogen. was added and stirred at 60° C. for 72 hours. The resulting reaction solution was added to 200 g of toluene. The precipitate was collected by filtration, washed with heptane, and dried in a vacuum to obtain 0.75 g of photo-alignable polymer 1. The yield was 75% based on compound (M1-1-1). GPC measurement revealed that the obtained photo-alignable polymer 1 had a number average molecular weight of 28,200, a weight average molecular weight of about 51,300, an Mw/Mn of 1.82, and a monomer content of 0.5%.

Synthesis Examples 2 and 3: Synthesis of photo-alignable polymer 2 and photo-alignable polymer 3 Macromolecules, Vol. 39, No. 26, 9357 (2006), photo-alignable polymer 2 and photo-alignable polymer 3 having the following structures were synthesized. The numerical values in parentheses in the following structural formulas represent the mole fraction of each structural unit with respect to the total structural units of photo-alignable polymer 2 and photo-alignable polymer 3.

Synthesis Example 4 Synthesis of Photo-Orientable Polymer 4 According to the method for synthesizing photo-orientable polymer 2 and photo-orientable polymer 3, photo-orientable polymer 4 having the following structure was prepared. The numerical values in parentheses in the following structural formula represent the mole fraction of each structural unit with respect to all the structural units of the photo-alignable polymer 4.

The weight average molecular weights of the polymers were approximately 100,000, polymer 2, approximately 90,000, and polymer 4, approximately 95,000 in terms of polystyrene.

2 parts of the photo-alignable polymer (any of photo-alignable polymers 1 to 4) prepared above and 98 parts of o-xylene are mixed, and the mixture is stirred at 80° C. for 1 hour to obtain a polymer solution. rice field. Hereinafter, the polymer solution containing polymer 1, the polymer solution containing polymer 2, the polymer solution containing polymer 3, and the polymer solution containing polymer 4 are referred to as polymer solution 1, polymer solution 2, polymer solution 3, and polymer solution 4, respectively.

(2) Composition for forming photo-alignment film and preparation of laminate Example 1
To the polymer 1 solution, 10 parts by mass of KBE-903 (manufactured by Shin-Etsu Chemical Co., Ltd.) per 100 parts by mass of the polymer, and an amount of formic acid that provides a molar ratio of 5 [mol/mol] to KBE-903 are added. to obtain a composition for forming a photo-alignment film.

(3) Preparation of Composition for Forming Polarizing Film A composition for forming a polarizing film was obtained by mixing the following components and stirring at 80° C. for 1 hour. The following polymerizable liquid crystal compound and dichroic dye were each prepared by the methods described in Examples of JP-A-2013-101328.

· 75 parts of the polymerizable liquid crystal compound represented by the formula (A-6)

· 25 parts of a polymerizable liquid crystal compound represented by the formula (A-7)

・ 2.8 parts of dichroic dye (1) shown below

- 2.8 parts of dichroic dye (2) shown below

・ 2.8 parts of dichroic dye (3) shown below

・Polymerization initiator: 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals) 6 parts ・Leveling agent: Polyacrylate compound (BYK-361N ; manufactured by BYK-Chemie) 1.2 parts

・溶剤：シクロペンタノン ２５０部 - Compound B-2: a compound having the following structure (trade name: Laromer (registered trademark) LR-9000, manufactured by BASF) 2 parts

・Solvent: 250 parts of cyclopentanone

(4) Creation of acrylic resin film An acrylic resin film was created based on the description of JP-A-2020-56835. Polyfunctional acrylate monomer (ethylene oxide (12) dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., "NK Ester A-DPH-12E"): 90 parts, urethane acrylate polymer (urethane acrylate (Nippon Synthetic Chemical Industrial Co., Ltd., "Shiko UV-3310B"): 10 parts, radical polymerization initiator (phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide (BASF, "Irgacure 819")): 3 parts , solvent (methyl ethyl ketone): 10 parts were mixed and stirred at 50° C. for 4 hours to obtain a composition for forming an acrylic resin layer.
The release-treated surface of a release-treated polyethylene terephthalate film (SP-PLR382050 manufactured by Lintec) (release film) was subjected to corona treatment, and then a composition for forming an acrylic resin layer was applied by a bar coating method (# 2 30 mm/sec), and a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.) was used to expose the composition for forming a resin layer to ultraviolet rays at an exposure amount of 500 mJ/cm ² (365 nm standard). By irradiating the coating layer, a release film with a resin layer having an acrylic resin layer formed on the surface of the release film was obtained. The thickness of the acrylic resin layer was 1.5 μm.

(5) Preparation of polarizing element An acrylic resin film as a substrate was cut into a square of 10 cm x 10 cm, and a corona treatment apparatus (AGF-B10; manufactured by Kasuga Denki Co., Ltd.) was used to introduce polar groups onto the surface of the substrate. The treatment was performed once under the conditions of an output of 0.3 kW and a treatment speed of 3 m/min. The composition for forming a photo-alignment film was applied to the corona-treated surface using a bar coater, dried at 80° C. for 1 minute, and exposed to a polarized UV irradiation device (SPOT CURE SP-7 with a polarizer unit; USHIO INC.). A photo-alignment film was formed by carrying out polarized UV exposure with an integrated light amount of 100 mJ/cm ² using a polarizer. The thickness of the resulting photo-alignment film was measured with an ellipsometer M-220 (manufactured by JASCO Corporation) and found to be 40 nm.

After applying the composition for forming a polarizing film on the obtained photo-alignment film using a bar coater, it was dried in a drying oven set at 120° C. for 1 minute.

After that, using a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio Inc.), by irradiating ultraviolet rays (under nitrogen atmosphere, wavelength: 365 nm, integrated light amount at wavelength 365 nm: 1000 mJ / cm ² ), A polarizing film in which the polymerizable liquid crystal compound and the dichroic dye were oriented was formed to obtain a laminate (1) consisting of substrate/photo-alignment film/polarizing film. At this time, when the thickness of the polarizer was measured by an ellipsometer, it was 2.0 μm.

Examples 2-9
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Example 1, except that the amount of acid added in the composition for forming a photo-alignment film was changed as shown in Table 1.

Examples 10-17
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Example 4 except that the amount of the silane coupling agent added was changed as shown in Table 1 in the composition for forming a photo-alignment film.

Example 18
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Example 1 except that p-toluenesulfonic acid was used as the acid and the molar ratio between the acid and the silane coupling agent was 3.

Example 19
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Example 1 except that acrylic acid was used as the acid and the molar ratio between the acid and the silane coupling agent was 22.

Example 20
A composition for forming a photo-alignment film and a laminate were produced in the same manner as in Example 19, except that acetic acid was used as the acid.

Example 21
A composition for forming a photo-alignment film was prepared in the same manner as in Example 3, except that the polymer solution 2 was used instead of the polymer solution 1.

Example 22
A composition for forming a photo-alignment film was prepared in the same manner as in Example 3, except that polymer solution 3 was used instead of polymer solution 1.

Example 23
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Example 3, except that polymer solution 4 was used instead of polymer solution 1.

Comparative example 1
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Example 1, except that the silane coupling agent and acid were not added.

Comparative example 2
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Example 1, except that no acid was added.

Comparative example 3
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Comparative Example 2, except that polymer solution 2 was used instead of polymer solution 1.

Comparative example 4
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Comparative Example 2, except that polymer solution 3 was used instead of polymer solution 1.

Comparative example 5
A composition for forming a photo-alignment film and a laminate were prepared in the same manner as in Comparative Example 2, except that polymer solution 4 was used instead of polymer solution 1.

(6) Evaluation (6)-1. Liquid Stability of Composition for Forming Photo-Alignment Film The liquid stability of the composition for photo-alignment film was evaluated as follows.
After the composition for forming a photo-alignment film is produced, it is filled in a brown bottle and stored at rest at 25°C for a predetermined time (1 hour, 2 hours, 3 hours, 1 day, 5 days and 7 days) after production. After the passage of time, the presence or absence of white turbidity and precipitates was visually confirmed, and the liquid stability was evaluated according to the following criteria.
〇: No cloudiness (no cloudiness can be confirmed even when exposed to light)
△: Slight cloudiness (cloudiness can be confirmed by exposing it to light)
×: Cloudy (white turbidity can be confirmed without exposure to light)

(6)-2. Adhesion between Substrate and Alignment Film Adhesion between the substrate (acrylic resin film) and the photo-alignment film in the obtained laminate was evaluated by the following crosshatch test.
(crosshatch test)
The adhesion between the photo-alignment film and the acrylic resin film in the obtained laminate was evaluated by a crosshatch test (JIS "cross-cut adhesion test") based on JIS D0202-1988. The surface of the acrylic resin film of the 10 cm×10 cm laminate was scratched in a 10×10 grid at intervals of 2 mm, penetrating the acrylic resin film and the photo-alignment film to prepare a grid. Adhesive tape (width 25 mm, manufactured by Nichiban) was completely adhered to the grid surface thus prepared. The adhesive tape was then pulled off in a direction 90° to the surface. The number of grids left without peeling was measured, and adhesion was evaluated according to the following criteria.
○: 50 or more remaining △: 10 or more and 49 or less remaining ×: less than 9 In addition, for the peeled grid pattern, the peeled interface is between the photo-alignment film and the substrate by X-ray photoelectron spectroscopy (XPS). It was confirmed.

(6) Presence or absence of poor alignment after 3.7 days An alignment film was formed from the composition for forming a photo-alignment film 7 days after production, and a laminate was produced using the alignment film in the same procedure as above. . The resulting laminate of 10 cm×10 cm was placed on a backlight, visually observed, and evaluated according to the following criteria.
○: No poor orientation △: Poor orientation occurs partially ×: Poor orientation occurs over the entire surface

Table 1 shows the evaluation results of the compositions for forming a photo-alignment film and the laminates obtained in Examples and Comparative Examples. In Table 1, SC agent represents a silane coupling agent, and bp represents a boiling point. Further, the amount of the silane coupling agent added represents parts by mass with respect to 100 parts by mass of the photo-alignable polymer. In the table, "-" in the evaluation results indicates that evaluation was not performed.

Compared with Comparative Example 1 containing no silane coupling agent and acid, the adhesion between the photo-alignment film formed from the photo-alignment film-forming composition of Examples 1 to 20 and the substrate is good. . In addition, it can be seen that the liquid stability of the compositions for forming a photo-alignment film of Examples 1 to 23 is improved as compared with Comparative Examples 2 to 5, which contain a silane coupling agent but do not contain an acid.

Claims (14)

A composition for forming a photo-alignment film, comprising a photo-alignment polymer having a photoreactive group, a silane coupling agent, an acid and a solvent. 2. The composition of claim 1, wherein the photoorientable polymer has photoreactive groups that undergo a dimerization reaction. 3. The composition according to claim 1 or 2, wherein the photo-orientable polymer is a (meth)acrylic polymer. The composition according to any one of claims 1 to 3, wherein the photo-orientable polymer further has carboxyl groups. The composition according to any one of claims 1 to 4, wherein the photo-orientable polymer has a weight average molecular weight of 10,000 or more and 1,000,000 or less. The composition according to any one of claims 1 to 5, wherein the silane coupling agent has at least one group selected from the group consisting of primary amino groups and secondary amino groups. The composition according to any one of claims 1 to 6, wherein the content of the silane coupling agent is 0.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the photo-alignable polymer. The composition according to any one of claims 1 to 7, wherein said acid comprises at least one selected from the group consisting of formic acid, toluenesulfonic acid, acrylic acid and acetic acid. The composition according to any one of claims 1 to 8, wherein the acid and the silane coupling agent have a molar ratio of 1 or more and 50 or less. A photo-alignment film obtained by curing the composition according to any one of claims 1 to 9. A laminate comprising a substrate and the photo-alignment film according to claim 10 . 12. The laminate according to claim 11, wherein the base material has a film thickness of 1 [mu]m or more and 20 [mu]m or less. A polarizing element comprising a substrate, the photo-alignment film of claim 10, and a polarizing film. 14. The polarizing element according to claim 13, having a thickness of 1 μm or more and 10 μm or less.