JP2008083394A - Optically anisotropic film and method for producing the same - Google Patents

Abstract

An optically anisotropic film having improved heat stability in a polymer film with controlled optical anisotropy and a method for producing the same.
SOLUTION: A composition containing a high molecular weight polymer containing a repeating unit having both a polymerizable group and a mesogenic group and a repeating unit having a photoreactive group as constituent units is subjected to optical anisotropy by light irradiation. An optically anisotropic film obtained by allowing the polymerizable group to crosslink after being expressed.
[Selection figure] None

Description

  The present invention relates to a film that exhibits optical anisotropy by light irradiation and a method for producing the film.

  CRT (Cathode Ray Tube) has been mainly used so far as an image display device used for OA devices such as word processors, notebook personal computers, personal computer monitors, portable terminals, and televisions. In recent years, liquid crystal display devices have been widely used instead of CRTs because of their thinness, light weight, and low power consumption. Various polymer films have been used for various applications in these image display devices. The liquid crystal display device has a liquid crystal cell and a polarizing plate. The polarizing plate is usually composed of a protective film and a polarizer, and is obtained by dyeing a polarizer composed of a polyvinyl alcohol film with iodine, stretching, and laminating both surfaces with a protective film. In addition, optical compensation films and retardation films are used in many cases in order to improve the contrast of image display devices and expand the viewing angle range. As such an optical compensation film or retardation film, a stretched film having refractive index anisotropy or a film obtained by aligning and polymerizing a liquid crystal compound is used. Examples of films obtained by aligning and polymerizing liquid crystal compounds include films formed by fixing the alignment state of a material in which a polymerizable group such as an oxetanyl group is introduced to the end of a mesogenic side chain of a polymer liquid crystal via a spacer. Is known (Patent Document 1)

  In recent years, regarding polymer films used in these liquid crystal display devices, in order to further improve the viewing angle characteristics and contrast of the liquid crystal display devices, more precise control of refractive index anisotropy is required. At the same time, reducing manufacturing costs is an issue in terms of manufacturing. Under such circumstances, the stretched film has a problem that the stretching direction during production is limited and it is difficult to precisely control the refractive index anisotropy. On the other hand, a film obtained by aligning and polymerizing a liquid crystal compound generally aligns the liquid crystal compound using an alignment film or an alignment substrate. Therefore, for example, since it is necessary to separately manufacture an alignment film and an alignment substrate, there is a problem that the manufacturing process becomes complicated. Furthermore, also from the viewpoint of precise control of refractive index anisotropy, the refractive index anisotropy largely depends on the alignment film or the alignment substrate.

  Therefore, in recent years, a method for producing a film having refractive index anisotropy that does not require an alignment film or an alignment substrate has been developed. For example, a method for producing a film having refractive index anisotropy by irradiating a film made of a polymer compound having a photoisomerizable group such as azobenzene, or a film made of the polymer compound and a liquid crystal compound from an oblique direction. Is known (for example, Patent Documents 2 and 3). However, the film produced in this manner has a problem in terms of stability because the orientation of the photoisomerization group and the orientation of the liquid crystal compound are not fixed.

  Next, after irradiating polarized light to a film-like molded product of a mixture comprising a liquid crystal monomer (or prepolymer) having a crosslinkable group and a photoreactive monomer (or oligomer or polymer), the liquid crystal monomer is photo-aligned. A method for producing a film having refractive index anisotropy in which the liquid crystal monomer is cross-linked again by light irradiation to fix the alignment state is known (for example, Patent Document 4). However, this method may cause a problem that a part of the liquid crystal monomer is polymerized at the time of irradiation of polarized light, causing a problem in the optical characteristics of the obtained film. In order to solve such a problem, a method of reacting a photoreactive monomer in a state in which the polymerization reaction of the liquid crystal monomer is suppressed at the time of polarized light irradiation is adopted. It is said that there is a problem that the obtained film is not sufficiently crosslinked and easily damaged.

  On the other hand, a film-like molded product of a mixture of a liquid crystal polymer and a photoreactive compound is prepared, and the film-like molded product is irradiated with light to change the molecular structure of the photoreactive compound, so that the liquid crystal polymer is in a liquid crystal state. A method for producing an optical film in which a liquid crystal polymer is aligned by heating to a temperature higher than or equal to the temperature of the liquid crystal polymer and then cooled below the temperature at which the liquid crystal polymer exhibits a liquid crystal state to fix the alignment state (for example, Patent Document 5). However, the optical film produced by such a method has a problem that the stability to heat is weak and the refractive index anisotropy is reduced and disappears when heated to a temperature higher than the liquid crystal state.

  Furthermore, in a polymer liquid crystal in which a photoreactive group such as a cinnamoyl group is directly introduced through a spacer at the end of a mesogenic side chain, the refractive index is changed by reorienting by irradiating polarized light and then annealing. An anisotropic film is disclosed (for example, Patent Documents 6 to 8). However, with respect to these methods as well, as apparent from the fact that reorientation can be carried out by annealing, the optical characteristics greatly fluctuate due to heating, so that the stability to heat is essentially low.

JP 2004-123882 A Japanese Patent No. 3315476 Japanese Patent No. 3312063 Special table 2002-517605 gazette JP 2005-62765 A JP 2004-258426 A JP 2002-90539 A JP 11-189665 A

  An object of the present invention is to provide an optically anisotropic film having improved stability to heat in a polymer film with controlled optical anisotropy, and a method for producing the same, in order to solve the above-described problems. Is to provide.

Under such circumstances, as a result of intensive studies by the present inventors, it has been found that the above-described problems can be solved by the following means.
(1) A composition comprising a high molecular weight polymer comprising as a constituent unit a repeating unit having both a polymerizable group and a mesogenic group and a repeating unit having a photoreactive group.
(2) The composition according to (1), wherein the repeating unit having both the polymerizable group and the mesogenic group is a repeating unit represented by the following general formula (1).
General formula (1)

（式中、Ｒ¹は水素原子または置換基を表し、Ｓ¹およびＳ²はそれぞれ独立して二価の連結基を表し、Ｍはメソゲン基を表し、Ｐ¹は重合性基を示す。）
（３）前記重合性基が、カチオン重合性基である、（１）または（２）に記載の組成物。
（４）前記重合性基が、環状エーテル基、オキセタニル基またはビニルエーテル基である、（１）または（２）に記載の組成物。
（５）前記光反応性基を有する繰り返し単位が下記一般式（２）で表される繰り返し単位である、（１）〜（４）のいずれか１項に記載の組成物。
一般式（２）

(In the formula, R ¹ represents a hydrogen atom or a substituent, S ¹ and S ² each independently represents a divalent linking group, M represents a mesogenic group, and P ¹ represents a polymerizable group.)
(3) The composition according to (1) or (2), wherein the polymerizable group is a cationic polymerizable group.
(4) The composition according to (1) or (2), wherein the polymerizable group is a cyclic ether group, an oxetanyl group or a vinyl ether group.
(5) The composition according to any one of (1) to (4), wherein the repeating unit having the photoreactive group is a repeating unit represented by the following general formula (2).
General formula (2)

（式中、Ｒ¹は水素原子または置換基を表し、Ｙ¹は酸素原子または−ＮＲ²−（Ｒ²は、水素原子またはアルキル基を表す。）を表し、Ａｒ¹およびＡｒ²は、それぞれ独立して炭素数１〜１０の芳香環を示し、Ａｒ¹およびＡｒ²は、それぞれ置換基を有していてもよい。ｎは１〜３の整数を表す。）
（６）前記光反応性基を有する繰り返し単位が下記一般式（３）で表される繰り返し単位であることを特徴とする、（１）〜（４）のいずれか１項に記載の組成物。
一般式（３）

(Wherein R ¹ represents a hydrogen atom or a substituent, Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group), and Ar ¹ and Ar ² are each Independently represents an aromatic ring having 1 to 10 carbon atoms, Ar ¹ and Ar ² may each have a substituent, and n represents an integer of 1 to 3).
(6) The composition according to any one of (1) to (4), wherein the repeating unit having a photoreactive group is a repeating unit represented by the following general formula (3): .
General formula (3)

（式中、Ｒ¹は水素原子または置換基を表し、Ｒ³は置換基を表し、Ｙ¹は酸素原子または−ＮＲ²−（Ｒ²は、水素原子またはアルキル基を示す。）を表し、Ａｒ³は、ベンゼン環、フラン環またはナフタレン環を示し、置換基を有していてもよい。ｍは０〜４の整数を表す。）
（７）（１）〜（６）のいずれか１項に記載の組成物を、光照射により光学異方性を発現させた後、前記重合性基を架橋してなることを特徴とする光学異方性フィルム。
（８）偏光子と、該偏光子の少なくとも片面に設けられた保護フィルムを有し、該保護フィルムが、（７）に記載の光学異方性フィルムを有する、偏光板。
（９）（７）に記載の光学異方性フィルム、または、（８）に記載の偏光板を有する液晶表示装置。
（１０）重合性基とメソゲン基の両方を有する繰り返し単位と、光反応性基を有する繰り返し単位を構成単位として含む高分子重合体を含む組成物を膜状に形成する工程、該膜状に形成した組成物に光を照射する工程、該光を照射した組成物に架橋重合開始剤を塗布する工程、および、重合性基を架橋させる工程を含む、光学異方性フィルムの製造方法。
（１１）前記架橋重合開始剤が光酸発生剤である、（１０）に記載の光学異方性フィルムの製造方法。
（１２）前記光照射工程の後に熱処理を施す工程を含む、（１０）または（１１）に記載の光学異方性フィルムの製造方法。
（１３）前記膜状に成形する工程において、前記組成物を含む溶液を吹き付けることにより膜状とすることを特徴とする（１０）〜（１２）のいずれか１項に記載の光学異方性フィルムの製造方法。
（１４）下記一般式（１）で表される繰り返し単位と、下記一般式（２）で表される繰り返し単位とを構成単位として含む高分子重合体。
一般式（１）

(Wherein R ¹ represents a hydrogen atom or a substituent, R ³ represents a substituent, Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group); Ar ³ represents a benzene ring, a furan ring or a naphthalene ring, which may have a substituent, and m represents an integer of 0 to 4.)
(7) An optical device comprising the composition according to any one of (1) to (6), wherein optical anisotropy is expressed by light irradiation, and then the polymerizable group is crosslinked. Anisotropic film.
(8) A polarizing plate having a polarizer and a protective film provided on at least one surface of the polarizer, and the protective film having the optically anisotropic film according to (7).
(9) A liquid crystal display device having the optically anisotropic film according to (7) or the polarizing plate according to (8).
(10) A step of forming into a film a composition comprising a repeating unit having both a polymerizable group and a mesogenic group, and a polymer comprising a repeating unit having a photoreactive group as a constituent unit. A method for producing an optically anisotropic film, comprising: irradiating a formed composition with light; applying a crosslinking polymerization initiator to the composition irradiated with light; and crosslinking a polymerizable group.
(11) The method for producing an optically anisotropic film according to (10), wherein the crosslinking polymerization initiator is a photoacid generator.
(12) The method for producing an optically anisotropic film according to (10) or (11), including a step of performing a heat treatment after the light irradiation step.
(13) The optical anisotropy according to any one of (10) to (12), wherein in the step of forming into a film, the film is formed by spraying a solution containing the composition. A method for producing a film.
(14) A polymer comprising a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2) as constituent units.
General formula (1)

（式中、Ｒ¹は水素原子または置換基を表し、Ｓ¹およびＳ²はそれぞれ独立して二価の連結基を表し、Ｍはメソゲン基を表し、Ｐ¹は重合性基を示す。）
一般式（２）

(In the formula, R ¹ represents a hydrogen atom or a substituent, S ¹ and S ² each independently represents a divalent linking group, M represents a mesogenic group, and P ¹ represents a polymerizable group.)
General formula (2)

（式中、Ｒ¹は水素原子または置換基を表し、Ｙ¹は酸素原子または−ＮＲ²−（Ｒ²は、水素原子またはアルキル基を表す。）を表し、Ａｒ¹およびＡｒ²は、それぞれ独立して炭素数１〜１０の芳香環を示し、Ａｒ¹およびＡｒ²は、それぞれ置換基を有していてもよい。ｎは１〜３の整数を表す。）

(Wherein R ¹ represents a hydrogen atom or a substituent, Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group), and Ar ¹ and Ar ² are each Independently represents an aromatic ring having 1 to 10 carbon atoms, Ar ¹ and Ar ² may each have a substituent, and n represents an integer of 1 to 3).

  In the present invention, it is possible to provide an optically anisotropic film excellent in optical properties and stability.

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

The optically anisotropic film of the present invention comprises a polymer having at least a repeating unit having both a polymerizable group and a mesogenic group and a repeating unit having a photoreactive group as its constituent unit (hereinafter referred to as “in the present invention”). A composition comprising “a high-molecular polymer to be used”) is characterized in that it exhibits optical anisotropy by light irradiation and then crosslinks the polymerizable group.
Here, the high molecular polymer used in the present invention is obtained by connecting a repeating unit having both a polymerizable group and a mesogenic group and a repeating unit having a photoreactive group, directly or via a linking group. Also included is a polymer comprising one repeating unit (that is, a repeating unit derived from one type of monomer).

  A polymer generally refers to a polymer having a molecular weight of 10,000 or more, and a compound having a molecular weight of 1,000 or more and less than 10,000 is treated as a quasi-polymer. Also, those having a degree of polymerization of about 2 to 20 are called oligomers, and are distinguished from polymers (Iwanami Rikagaku Dictionary, 3rd edition supplement edition, edited by Tamamichi Bunichi et al., Page 449, Iwanami Shoten, 1982). . However, in the present invention, a polymer includes a quasi-polymer, a molecular weight of 1000 or more, and a degree of polymerization of 20 or more.

  In the repeating unit having both a polymerizable group and a mesogenic group in the polymer used in the present invention, the polymerizable group is not particularly limited, but a polymerizable group that undergoes cationic polymerization is preferable. As the cationic polymerizable group, generally known cationic polymerizable groups can be used. Specifically, alicyclic ether group, cyclic acetal group, cyclic lactone group, cyclic thioether group, spiro orthoester group, vinyloxy group Examples include groups. As a suitable thing, an oxetane ring can be mentioned, for example. Of these, alicyclic ether groups and vinyloxy groups are preferred, and epoxy groups, oxetanyl groups, and vinyloxy groups are particularly preferred.

In the repeating unit having both a polymerizable group and a mesogenic group in the polymer used in the present invention, the mesogenic group generally refers to a rigid site in a liquid crystal compound. However, the polymer used in the present invention does not necessarily have liquid crystallinity. As the mesogenic group, the structures described in Makromol. Chem., 190, 2255 (1989), Advanced Materials, 5, 107 (1993) and the like can be used.
More preferably, it is a mesogenic group represented by the following general formula (4).

General formula (4)

（一般式（４）中、Ｌ¹およびＬ²は、それぞれ、単結合または二価の連結基を表し、Ｃｙ¹、Ｃｙ²およびＣｙ³は、それぞれ、二価の環状基を表し、ｐは０〜２の整数を表す。ｐが２の場合、２つのＬ²は同じであっても異なっていてもよく、２つのＣｙ²も同じであっても異なっていてもよい。）

(In General Formula (4), L ¹ and L ² each represent a single bond or a divalent linking group, Cy ¹ , Cy ² and Cy ³ each represent a divalent cyclic group, and p is Represents an integer of 0 to 2. When p is 2, two L ² may be the same or different, and two Cy ² may be the same or different.

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

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

  In the general formula (4), p is preferably 0 or 1.

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

More specifically, the repeating unit having both a polymerizable group and a mesogenic group is preferably a repeating unit represented by the following general formula (1).
General formula (1)

（式中、Ｒ¹は水素原子または置換基を表し、Ｓ¹およびＳ²はそれぞれ独立して二価の連結基を表し、Ｍはメソゲン基を表し、Ｐ¹は重合性基を示す。）
Ｒ¹が置換基を表す場合、アルキル基またはハロゲン基を好ましい例として挙げることができる。
Ｒ¹は、水素原子、炭素数１〜６のアルキル基、クロロ基が好ましく、水素原子、メチル基、エチル基、クロロ基がより好ましく、水素原子がさらに好ましい。
Ｓ¹、Ｓ²は、好ましくは、それぞれ独立して、アルキレン基、アルケニレン基、アリーレン基、２価の複素環残基、−ＣＯ−、−ＮＲ⁵−（Ｒ⁵は炭素数が１〜６のアルキル基または水素原子）、−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ₂−およびそれらの組み合わせからなる群より選ばれる２価の連結基であることが好ましい。アルキレン基の炭素数は、１〜１２であることが好ましい。アルケニレン基の炭素数は、２〜１２であることが好ましい。アリーレン基の炭素数は、６〜１０であることが好ましい。アルキレン基、アルケニレン基およびアリーレン基は、可能であれば、置換基（アルキル基、ハロゲン原子、シアノ基、アルコキシ基、アシルオキシ基等）によって置換されていてもよいが、無置換であることが好ましい。
Ｓ¹、Ｓ²としては、−Ｏ−、−ＣＯ−、−ＮＲ⁵−（Ｒ⁵は炭素数が１〜６のアルキル基または水素原子）、アルキレン基またはアリーレン基を含んでいることが好ましく、−Ｏ−、アルキレン基またはアリーレン基を含んでいることが特に好ましい。さらに、Ｓ¹、Ｓ²は、−Ｏ−、アルキレン基またはアリーレン基のみから構成されていることが好ましい。
Ｍはメソゲン基、Ｐ¹は重合性基を示す。メソゲン基、重合性基に関しては前述のメソゲン基および重合性基の説明と同義であり、好ましい範囲も同義である。

(In the formula, R ¹ represents a hydrogen atom or a substituent, S ¹ and S ² each independently represents a divalent linking group, M represents a mesogenic group, and P ¹ represents a polymerizable group.)
When R ¹ represents a substituent, an alkyl group or a halogen group can be mentioned as a preferred example.
R ¹ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a chloro group, more preferably a hydrogen atom, a methyl group, an ethyl group, or a chloro group, and even more preferably a hydrogen atom.
S ¹ and S ² are preferably each independently an alkylene group, an alkenylene group, an arylene group, a divalent heterocyclic residue, —CO—, —NR ⁵ — (R ⁵ has 1 to 6 carbon atoms). A divalent linking group selected from the group consisting of —O—, —S—, —SO—, —SO ₂ — and combinations thereof. The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The arylene group preferably has 6 to 10 carbon atoms. The alkylene group, alkenylene group and arylene group may be substituted with a substituent (such as an alkyl group, a halogen atom, a cyano group, an alkoxy group, or an acyloxy group) if possible, but is preferably unsubstituted. .
S ¹ and S ² preferably include —O—, —CO—, —NR ⁵ — (R ⁵ is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom), an alkylene group, or an arylene group. , -O-, an alkylene group or an arylene group is particularly preferred. Further, S ¹ and S ² are preferably composed only of —O—, an alkylene group or an arylene group.
M represents a mesogenic group, and P ¹ represents a polymerizable group. The mesogenic group and the polymerizable group are the same as those described above for the mesogenic group and the polymerizable group, and the preferred range is also the same.

In the repeating unit having a photoreactive group of the polymer used in the present invention, the photoreactive group is, for example, a chemical structure of a functional group or a molecule having the functional group by irradiation with light from a single direction. It refers to a functional group that can change the orientation state and thereby change the anisotropy of the molecule in a specific direction.
Specifically, coumarin derivatives, styrylpyridine derivatives, azobenzene derivatives, cinnamic acid derivatives, chalcone derivatives, stilbenes, α-hydrazono-β-ketoesters, benzylidenephthalimidines, retinoic acid derivatives, spiropyrans, spirooxazines Anthracene derivatives and benzophenone derivatives are preferably used, cinnamic acid derivatives and chalcone derivatives are more preferable, and cinnamic acid derivatives are particularly preferable.

The repeating unit having a photoreactive group is preferably a repeating unit represented by the following general formula (2).
General formula (2)

（式中、Ｒ¹は水素原子または置換基を表し、Ｙ¹は酸素原子または−ＮＲ²−（Ｒ²は、水素原子またはアルキル基を表す。）を表し、Ａｒ¹およびＡｒ²は、それぞれ独立して炭素数１〜１０の芳香環を示し、Ａｒ¹およびＡｒ²は、それぞれ置換基を有していてもよい。ｎは１〜３の整数を表す。）

(Wherein R ¹ represents a hydrogen atom or a substituent, Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group), and Ar ¹ and Ar ² are each Independently represents an aromatic ring having 1 to 10 carbon atoms, Ar ¹ and Ar ² may each have a substituent, and n represents an integer of 1 to 3).

When R ¹ represents a substituent, an alkyl group and a halogen group can be mentioned as preferred examples. R ¹ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a chloro group, more preferably a hydrogen atom, a methyl group, an ethyl group, or a chloro group, and even more preferably a hydrogen atom.

Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group (preferably an alkyl group having 1 to 6 carbon atoms)), and may be an oxygen atom or —NH—. Preferably, it is an oxygen atom.

Ar ¹ is preferably a benzene ring, a thiophene ring, a furan ring, or a naphthalene ring, and more preferably a benzene ring.

When Ar ¹ has a substituent, examples of the substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, and an alkylcarbonyl having 1 to 6 carbon atoms. Group, C1-C6 alkylcarbonyloxy group, C1-C6 alkylcarbonylthio group, C1-C6 alkylcarbonylamino group, halogen group, cyano group, nitro group, cyano group, etc. More preferred substituents include methyl, ethyl, methoxy, fluorine, chloro, bromo, and cyano groups.

  These substituents may be substituted with other substituents, and preferred substituents in this case are also as defined above. Moreover, when it has two or more substituents, each substituent may be the same or different. If possible, the substituents may be bonded to each other to form a ring.

Ar ² is preferably a benzene ring, a furan ring, or a naphthalene ring, and more preferably a benzene ring. When Ar ² has a substituent, examples of the substituent include alkyl group, alkenyl group, alkynyl group, alkoxyl group, alkylthio group, alkylcarbonyl group, alkylcarbonyloxy group, alkylcarbonylthio group, alkylcarbonylamino group, alkyloxy group Examples include carbonyloxy group, alkyloxycarbonylthio group, alkyloxycarbonylamino group, alkylthiocarbonyloxy group, alkylaminocarbonylamino group, alkylaminocarbonyloxy group, halogen group, cyano group, nitro group, and aryl group. More preferred substituents are alkyl groups having 1 to 20 carbon atoms, alkoxyl groups having 1 to 20 carbon atoms, alkylthio groups having 1 to 20 carbon atoms, alkylcarbonyl groups having 1 to 20 carbon atoms, and 1 to 20 carbon atoms. Alkylca A bonyloxy group, an alkylcarbonylamino group having 1 to 20 carbon atoms, an alkyloxycarbonyloxy group having 1 to 20 carbon atoms, an alkyloxycarbonylthio group having 1 to 20 carbon atoms, an alkyloxycarbonylamino group having 1 to 20 carbon atoms, Examples thereof include an alkylaminocarbonyloxy group having 1 to 20 carbon atoms, a fluorine group, a chloro group, a bromo group, a cyano group, and a nitro group.
These substituents may be substituted with other substituents, and preferred substituents in this case are also as defined above. Moreover, when it has two or more substituents, each substituent may be the same or different. If possible, the substituents may be bonded to each other to form a ring.

  n represents an integer of 1 to 3, and is preferably 1 or 2.

Among the repeating units represented by the general formula (2), particularly preferred are repeating units represented by the following general formula (3).
General formula (3)

（式中、Ｒ¹は水素原子または置換基を表し、Ｒ³は置換基を表し、Ｙ¹は酸素原子または−ＮＲ²−（Ｒ²は、水素原子またはアルキル基を示す。）を表し、Ａｒ³は、ベンゼン環、フラン環またはナフタレン環を示し、置換基を有していてもよい。ｍは０〜４の整数を表す。）

(Wherein R ¹ represents a hydrogen atom or a substituent, R ³ represents a substituent, Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group); Ar ³ represents a benzene ring, a furan ring or a naphthalene ring, which may have a substituent, and m represents an integer of 0 to 4.)

The explanation about R ¹ and Y ¹ is synonymous with that described in the general formula (2), and the preferred range is also synonymous.
R ³ represents a substituent, and preferred substituents include an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, and an alkylcarbonyl group having 1 to 6 carbon atoms. , An alkylcarbonyloxy group having 1 to 6 carbon atoms, an alkylcarbonylthio group having 1 to 6 carbon atoms, an alkylcarbonylamino group having 1 to 6 carbon atoms, a halogen group, a cyano group, a nitro group, a cyano group, and the like. Particularly preferred substituents include methyl group, ethyl group, methoxy group, fluorine group, chloro group, bromo group and cyano group.
These substituents may be further substituted with these substituents. Moreover, when it has two or more substituents, they may be the same or different. If possible, they may be bonded to each other to form a ring.

Ar ³ represents a benzene ring, a furan ring, or a naphthalene ring, and a benzene ring is preferable. When Ar ³ has a substituent, examples of the substituent include alkyl, alkenyl, alkynyl, alkoxyl, alkylthio, alkylcarbonyl, alkylcarbonyloxy, alkylcarbonylthio, alkylcarbonylamino, alkyloxycarbonyl Oxy group, alkyloxycarbonylthio group, alkyloxycarbonylamino group, alkylthiocarbonyloxy group, alkylaminocarbonylamino group, alkylaminocarbonyloxy group, halogen group, cyano group, nitro group, aryl group, etc. Particularly preferred substituents are alkyl groups having 1 to 20 carbon atoms, alkoxyl groups having 1 to 20 carbon atoms, alkylthio groups having 1 to 20 carbon atoms, alkylcarbonyl groups having 1 to 20 carbon atoms and 1 to 20 carbon atoms, 1 to 1 carbon 0 alkylcarbonyloxy group, C1-C20 alkylcarbonylamino group, C1-C20 alkyloxycarbonyloxy group, alkyloxycarbonylthio group, alkyloxycarbonylamino group, C1-C20 alkylamino Examples thereof include a carbonyloxy group, a fluorine group, a chloro group, a bromo group, a cyano group, and a nitro group.
These substituents may be further substituted with these substituents. Moreover, when it has two or more substituents, they may be the same or different. If possible, they may be bonded to each other to form a ring.

m represents an integer of 0 to 4. In addition, when m is an integer of 2-4, several R < ³ > may be same or different, respectively. m is preferably an integer of 0 to 2.

The polymerizable monomer that can be used in the constitution of the polymer used in the present invention can be synthesized using a known synthesis method. For example, the method shown in the following synthesis scheme 1 can be mentioned as an example.
Scheme 1

In the above scheme 1, X ¹ and X ² represents a leaving group. Examples of preferred leaving groups include halogen atoms, mesyl groups, tosyl groups and the like. In addition, R ¹ , Y ¹ , Ar ¹ , Ar ² and n have the same definition as in the general formula (1).

  In step 1, the compound represented by formula S-2 is dissolved in a solvent and reacted with the compound represented by formula S-1 in the presence of a base to synthesize an intermediate represented by formula S-3. As the solvent, ether solvents such as tetrahydrofuran, amide solvents such as dimethylacetamide, and halogen solvents such as dichloromethane are suitable. As the base, any of inorganic and organic bases can be adopted, but organic bases such as triethylamine and diisopropylethylamine, and indefinite bases such as potassium carbonate and potassium hydrogen carbonate are suitable. The amount of the base used is preferably in the range of 0.5 to 10 equivalents relative to S-1, and more preferably in the range of 0.7 to 2 amounts. The reaction temperature is usually from −10 ° C. to the boiling point of the solvent, more preferably from 0 ° C. to room temperature. The reaction temperature is usually 10 minutes to 1 day, preferably 1 hour to 12 hours.

  In step 2, the compound represented by the formula S-3 obtained above is dissolved in a solvent and reacted with the compound represented by the formula S-4 in the presence of a base, so that it can be used in the intended present invention. A polymerizable monomer can be synthesized. As the solvent, ether solvents such as tetrahydrofuran, amide solvents such as dimethylacetamide, and halogen solvents such as dichloromethane are suitable. As the base, any of inorganic and organic bases can be adopted, but organic bases such as triethylamine and diisopropylethylamine, and inorganic bases such as potassium carbonate and potassium hydrogen carbonate are suitable. The amount of the base used is preferably in the range of 0.5 to 10 equivalents relative to S-3, and more preferably in the range of 0.7 to 2 amounts. The reaction temperature is usually from −10 ° C. to the boiling point of the solvent, more preferably from 0 ° C. to room temperature. The reaction temperature is usually 10 minutes to 1 day, preferably 1 hour to 12 hours.

As the polymer used in the present invention, a polymer containing a repeating unit represented by the general formula (1) and a repeating unit represented by the general formula (2) as its constituent units is particularly preferable.
Although the specific example is given to the following, this invention is not restrict | limited to the following specific examples. In addition, x, y, z in a formula shows the mole percentage of each repeating unit.

  The polymer used in the present invention is preferably a copolymer containing the repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (2). Among the repeating units constituting the polymer, the repeating unit represented by the general formula (1) is preferably 60 to 99 mol%, more preferably 70 to 95 mol%, More preferably, it is 80-90 mol%. Moreover, it is preferable that the repeating unit represented by the said General formula (2) is 1-40 mol%, It is more preferable that it is 5-30 mol%, It is further more preferable that it is 10-20 mol%. .

 Moreover, the high molecular polymer used by this invention can contain the arbitrary repeating units generally known besides the said repeating unit. The type of arbitrary repeating unit to be used and the mol% of the arbitrary repeating unit are appropriately selected depending on the type of monomer to be used or desired physical properties. For example, the content of the arbitrary repeating unit is preferably 50 mol% or less, more preferably 40 mol% or less, and still more preferably 30 mol% or less with respect to the total number of moles of monomers constituting the polymer. .

The weight average molecular weight (Mw) of the polymer used in the present invention is preferably 1,000 to 1,000,000, more preferably 5,000 to 200,000, and still more preferably 10,000 to 100,000. The weight average molecular weight can be measured as a value in terms of polystyrene (PS) using gel permeation chromatography (GPC).
Moreover, it is preferable that the glass transition temperature (Tg) of the high molecular polymer used by this invention is room temperature-50 degreeC.

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

  The radical polymerization method is not particularly limited, and can be performed by a known method such as an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, or a solution polymerization method. Solution polymerization, which is a typical radical polymerization method, will be described more specifically. The outlines of other polymerization methods are the same, and details thereof are described in, for example, “Polymer Chemistry Experimental Methods” edited by Polymer Society (Tokyo Kagaku Dojin, 1981).

  An organic solvent is used to perform the solution polymerization. These organic solvents can be arbitrarily selected as long as the objects and effects of the present invention are not impaired. These organic solvents are usually organic compounds having a boiling point in the range of 50 to 200 ° C. under atmospheric pressure, and organic solvents that uniformly dissolve each component are desirable. Examples of preferable organic solvents include alcohols such as isopropanol and butanol, ethers such as dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofuran and dioxane, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethyl acetate and acetic acid. Examples thereof include esters such as butyl, amyl acetate and γ-butyrolactone, amides such as dimethylamide and dimethylformamide, and aromatic hydrocarbons such as benzene, toluene and xylene. In addition, these organic solvents can be used individually by 1 type or in combination of 2 or more types. Furthermore, a water-mixed organic solvent in which water is used in combination with the above organic solvent is also applicable from the viewpoint of the solubility of the monomer and the polymer to be produced.

  Further, the solution polymerization conditions are not particularly limited, but for example, it is desirable to heat within a temperature range of 50 to 200 ° C. for 10 minutes to 30 hours. Furthermore, it is desirable to perform an inert gas purge not only during solution polymerization but also before the start of solution polymerization so that the generated radicals are not deactivated. Usually, nitrogen gas is suitably used as the inert gas.

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

  In the composition comprising the polymer used in the present invention, various additives can be used in combination with the polymer as necessary. For example, by using a plasticizer, a surfactant or the like in combination, the uniformity of the coating film, the strength of the film, the orientation of the polymer compound having a photoreactive group, and the like can be improved. 30 mass% or less is preferable with respect to the high molecular compound which has a photoreactive group, and, as for the total amount of these addition amounts, 10 mass% or less is more preferable.

  A conventionally well-known plasticizer is mentioned as a plasticizer. Specifically, phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diaryl phthalate, dimethyl glycol phthalate , Ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, glycol esters such as triethylene glycol dicaprylate, phosphate esters such as tricresyl phosphate, triphenyl phosphate, diisobutyl adipate , Dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate, triethyl citrate, glycerin triacetyl ester, and the like butyl laurate.

  Examples of the surfactant include conventionally known anionic, cationic, nonionic and amphoteric surfactants. Fluorine compounds are particularly preferred, and examples thereof include perfluoroalkylamine oxides, perfluoroalkylethylene oxide adducts, perfluoroalkyl group and hydrophilic group-containing polymers, perfluoroalkyl groups, hydrophilic groups, and lipophilic group-containing polymers.

  The optically anisotropic film of the present invention is obtained by causing the composition of the present invention to exhibit optical anisotropy by light irradiation and then crosslinking a polymerizable group contained in the composition. The optically anisotropic film of the present invention is usually formed on a support. Here, the thickness of the optically anisotropic film can be set to 1 to 4 μm, for example. As the support, for example, those described in JP-A-2002-38157 can be adopted. In particular, when the composition of the present invention is applied on a support to develop optical anisotropy, and then used integrally with the support without peeling off, the support is a glass substrate, or A polymer film having a light transmittance of 80% or more is preferred. The thickness of the support is preferably 10 to 500 μm, more preferably 20 to 200 μm, and still more preferably 35 to 110 μm.

  The optically anisotropic film of the present invention may be provided with an alignment layer, a release layer, an adhesive layer, another optically anisotropic layer, and the like as necessary.

  For the alignment layer, for example, a well-known alignment film generally used in the liquid crystal field can be adopted. As specific examples, an alignment film such as polyimide or polyvinyl alcohol subjected to rubbing alignment treatment, an azobenzene derivative, cinnamic acid derivative, or coumarin derivative subjected to photo-alignment treatment can be employed.

  A known release agent or the like can be used for the release layer. Examples of the release agent include silicon-based, phosphate ester-based, and fluorine-based release agents.

  A well-known adhesive etc. can be used for an adhesion layer. Specific examples include pressure sensitive adhesives such as acrylic, silicon, and vinyl ether. As the adhesive, an optically transparent adhesive is preferable.

  As another optically anisotropic layer, for example, an optically anisotropic layer composed of a polymer of an oriented rod-like or disk-like liquid crystal compound can be exemplified.

  The optically anisotropic film of the present invention is, for example, a step of forming a film of a composition comprising the polymer used in the present invention (film forming step), a step of irradiating light to develop optical anisotropy ( It can be produced through a light irradiation step), a step of applying a crosslinking polymerization initiator to the film irradiated with light (initiator application step), and a step of crosslinking the polymerizable group (crosslinking step). Below, it demonstrates by a specific example regarding each process of the manufacturing method of the optically anisotropic film of this invention.

(Film formation process)
The polymer film used in the present invention can be prepared by dissolving the polymer in a solvent and using it as a dope, applying the dope on a suitable support and then drying. As the coating method, known methods such as curtain coating method, extrusion coating method, roll coating method, spin coating method, ink jet method, dip coating method, bar coating method, spray coating method, slide coating method, print coating method, etc. Is adopted. Moreover, you may use the solvent cast method which casts on a drum or a band, evaporates a solvent, and forms a film. A general solvent casting method is described in each specification of US Pat. No. 2,336,310, Japanese Patent Publication No. 45-4554, and the like.

  In the preparation of the dope, the solvent to be dissolved is not particularly limited. For example, ester solvents such as ethyl acetate, ketone solvents such as methyl ethyl ketone, ether solvents such as tetrahydrofuran, halogen solvents such as chloroform and dichloromethane, or cyclohexanone, Examples thereof include solvents such as dimethylformamide, and mixed solvents thereof. The concentration of the dope is preferably adjusted so that the solid content is 10 to 40% by weight. The solid content is more preferably 18 to 35% by weight. The dope may be subjected to a filtration step if necessary.

  Two or more dopes can be cast. The surface of the drum or band is preferably finished in a mirror state. The obtained film is peeled off from the drum or band to produce a polymer film. The stripping step may be performed after light irradiation, which is a subsequent step, or after a coating step and a crosslinking step, which are subsequent steps, as necessary. Moreover, without peeling off, it may be integrated with the support and provided as an optically anisotropic film.

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

(Light irradiation process)
The polymer film obtained above or the polymer film formed on the support is irradiated with light to develop the refractive index anisotropy of the polymer film and the optical anisotropy is controlled. Manufacturing. Light irradiation may be performed while stretching the polymer film as necessary.

The light irradiation in the present invention is an operation for causing a photoreaction in the photoreactive compound. The wavelength of light used varies depending on the photoreactive compound used, and is not particularly limited as long as it is a wavelength necessary for the photoreaction. Preferably, the peak wavelength of light used for light irradiation is 200 nm to 700 nm, more preferably ultraviolet light having a peak wavelength of light of 400 nm or less. The light intensity varies depending on the required optical properties and the type of the polymer used in the present invention, and is not particularly limited. Usually, the range of 1 mJ / cm ^{2 to} 600 J / cm ² is preferable, and the range of 10 mJ / cm ^{2 to} 300 J / cm ² is more preferable.

  The light source used for light irradiation is a commonly used light source such as a tungsten lamp, a halogen lamp, a xenon lamp, a xenon flash lamp, a mercury lamp, a mercury xenon lamp, a carbon arc lamp, or various lasers (for example, a semiconductor laser, Helium neon laser, argon ion laser, helium cadmium laser, YAG laser), light emitting diode, cathode ray tube, and the like.

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

  As the light to be irradiated, a method of irradiating the polymer film with light from the upper surface or the back surface is perpendicular or oblique to the polymer film. Vertical irradiation is preferable. After the light irradiation, a heating operation may be performed as necessary, and the same or different light as described above may be irradiated.

(Heat treatment process)
You may heat-process as needed after the said polarized light irradiation process. The crosslinking temperature and heating time are not particularly limited, but are set in a range that does not impair the required optical characteristics or in a range that can exhibit the required optical characteristics. Usually, the heating temperature is preferably in the range of 0 to 300 ° C, more preferably in the range of room temperature to 150 ° C. The heating time is usually preferably in the range of 1 second to 1 day, and more preferably in the range of 10 seconds to 6 hours.

(Initiator application process)
A solution of a cross-linking polymerization initiator is applied to the film obtained above that exhibits optical anisotropy. The solvent for dissolving the crosslinking polymerization initiator is not particularly limited, but a solvent that does not dissolve the film exhibiting the optical anisotropy is employed. Specifically, for example, ester solvents such as ethyl acetate, ketone solvents such as methyl ethyl ketone and cyclohexanone, ether solvents such as tetrahydrofuran, halogen solvents such as chloroform and dichloromethane, or alcohol solvents such as methanol and ethanol, Examples thereof include nitrile solvents such as acrylonitrile and mixed solvents thereof. Alcohol solvents such as methanol and ethanol, and nitrile solvents such as acrylonitrile are particularly preferred. Moreover, you may add a required additive as needed. The solid content of the solution used is preferably 0.1 to 35% by weight, more preferably 0.5 to 25% by weight. The solution to be used may add a filtration process as needed. As the coating method, known methods such as curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, ink jet method, print coating method, etc. Is adopted.

  As the crosslinking polymerization initiator, an appropriate crosslinking polymerization initiator is employed depending on the type of the polymerizable group of the polymer used in the present invention. For example, when the polymerizable group is a cationic polymerizable group such as a cyclic ether group, an oxetanyl group, or a vinyl ether group, known photoacid generators and photocation initiators are particularly preferable examples. As the photoacid generator, diazodisulfone or triarylsulfonium photoacid generators can be used. Specifically, diazodisulfone photoacid generators such as WPAG-145, WPAG-170, and WPAG-199 (all manufactured by Wako Pure Chemical), WPAG-281, WPAG-336, and WPAG-367 (all Wako Pure) Medicinal product), SB 1A, SB 2B, SB 2B F, SB 3C (all manufactured by Nippon Shibel Hegner), UVI-6974, UVI-6990 (made by Union Carbide), FX512 (made by 3M), KI-85 (made by Degussa) Commercially available photoacid generators such as triarylsulfonium photoacid generators can be used. As the photocationic initiator, diphenyliodonium salt or the like can be used. Specifically, a photocation initiator such as WPI-113 (manufactured by Wako Pure Chemical Industries, Ltd.), MC AA, MC BB, MC CC, MC CC PF, MC CC F (all manufactured by Nippon Siebel Hegner) or the like can be used.

(Crosslinking process)
The film on which optical anisotropy has been applied to which the crosslinking polymerization initiator has been applied is irradiated with light again to perform crosslinking. The light irradiation may be non-polarized light or polarized light, but non-polarized light is preferably used. The wavelength of light used varies depending on the photoacid generator used, and is not particularly limited as long as it is a wavelength necessary for the photoreaction. Preferably, it is ultraviolet light having a peak wavelength of 400 nm or less. The crosslinking temperature and heating time are not particularly limited, but are set in a range that does not impair the required optical characteristics or in a range that can exhibit the required optical characteristics. Usually, the heating temperature is preferably in the range of 0 ° C to 300 ° C, more preferably in the range of room temperature to 150 ° C. The heating time is usually preferably in the range of 1 second to 1 day, and more preferably in the range of 10 seconds to 6 hours.

  Through the above steps, the optically anisotropic film of the present invention can be produced.

<Applications of optically anisotropic films>
The optically anisotropic film of the present invention can be used for, for example, a polarizing plate (elliptical polarizing plate) in combination with a polarizer. Moreover, it contributes to expansion of a viewing angle by applying to a transmissive liquid crystal display device in combination with a polarizer. The polarizing plate of the present invention comprises a polarizer and a protective film provided on at least one surface of the polarizer, and the protective film is the optically anisotropic film of the present invention. The liquid crystal display device of the present invention is characterized by having the optically anisotropic film of the present invention. Hereinafter, an elliptically polarizing plate and a liquid crystal display device using the optically anisotropic film of the present invention will be described in detail.

[Elliptically polarizing plate]
The elliptically polarizing plate can be produced by laminating the optically anisotropic film of the present invention and a polarizer. By using the optically anisotropic film of the present invention, an elliptically polarizing plate capable of expanding the viewing angle of a liquid crystal display device can be provided. Examples of the polarizer include an iodine polarizer, a dye polarizer using a dichroic dye, and a polyene polarizer. In general, iodine-based polarizers and dye-based polarizers can be produced using polyvinyl alcohol-based films. The polarization axis of the polarizer corresponds to a direction perpendicular to the stretching direction of the film.

  The polarizer is laminated on the optically anisotropic layer side of the optically anisotropic film. It is preferable to provide a protective film (transparent protective film) having a light transmittance of 80% or more as a protective film on the surface of the polarizer opposite to the side on which the optically anisotropic film is laminated. As the transparent protective film, a cellulose ester film is preferably used, more preferably a triacetyl cellulose film. The cellulose ester film is preferably formed by a solvent cast method. The thickness of the protective film is preferably 20 to 500 μm, and more preferably 50 to 200 μm.

[Liquid Crystal Display]
By using the optically anisotropic film of the present invention, a liquid crystal display device having an enlarged viewing angle can be provided. In addition, a liquid crystal display device that can display a high-quality image without display unevenness can be provided. As an optically anisotropic film for a liquid crystal cell of Twisted Nematic (TN) mode, for example, JP-A-6-214116, U.S. Pat. Nos. 5,583,679 and 5,646,703, It can be used in accordance with the description in German Patent Publication 3911620A1. Moreover, it can utilize according to description of Unexamined-Japanese-Patent No. 10-54982 as an optically anisotropic film for liquid crystal cells of an In-Plane Switching (IPS) mode or a Ferroelectric Liquid Crystal (FLC) mode. Further, optically anisotropic films for liquid crystal cells in Optically Compensatory Bend (OCB) mode or Hybrid Aligned Nematic (HAN) mode include US Pat. No. 5,805,253 and International Publication WO96 / 37804. Available as described. Furthermore, as an optically anisotropic film for a liquid crystal cell in Super Twisted Nematic (STN) mode, it can be used according to the description in JP-A-9-26572. As an optically anisotropic film for a liquid crystal cell in a vertically aligned (VA) mode, it can be used in accordance with the description in Japanese Patent No. 2866372.

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

Synthesis Example 1 Synthesis of monomer (LM-1) having a photoreactive group In a 2 L three-necked flask, 134 g (1.22 mol) of hydroquinone and 54 mL (0.39 mol) of triethylamine were dissolved in 1200 mL of tetrahydrofuran, and the mixture was ice-cooled. A solution prepared by dissolving 27.18 g (0.3 mol) of acrylic acid chloride in 100 mL of tetrahydrofuran was added dropwise. After returning to normal temperature and stirring for 5 hours, 500 mL of water was added, liquid separation was performed, and the aqueous layer was extracted three times with 300 mL of hexane. The organic layer and the extraction layer were combined and dried over magnesium sulfate, and then the solvent was distilled off under reduced pressure. The obtained compound was purified by silica gel chromatography using a mixed solvent of hexane-ethyl acetate (volume ratio of hexane-ethyl acetate = 3/1) as a developing solvent to obtain 16 g of 4-hydroxyphenyl acrylate (yield). Rate 32%).

¹ H-NMR (CDCl ₃ , δ) 7.00 (2H, d), 6.80 (2H, d), 6.60 (1H, dd), 6.35 (1H, dd), 6,000 (1H, dd), 5.20 (1H, s)

  In a 1 L three-necked flask, 13 g (79 mmol) of 4-hydroxyphenyl acrylate obtained above, 22 mL (158 mmol) of triethylamine and 0.1 g of nitrobenzene were dissolved in 200 mL of tetrahydrofuran, and 14.5 g of cinnamic acid chloride was cooled with ice. A solution of (87 mmol) in 50 mL of tetrahydrofuran was slowly added. After returning to normal temperature and stirring for 3 hours, 100 mL of saturated brine and 100 mL of ethyl acetate were added to perform liquid separation, and the aqueous layer was extracted twice with 100 mL of ethyl acetate. The organic layer and the extraction layer were combined and dried over magnesium sulfate, and then the solvent was distilled off under reduced pressure. The obtained compound was purified by silica gel chromatography using a mixed solvent of hexane-ethyl acetate (volume ratio of hexane-ethyl acetate = 3/1) as a developing solvent, and 13 g of a monomer having a photoreactive group (LM-1 ) Was obtained (yield 57%).

LM-1

¹ H-NMR (CDCl ₃ , δ): 7.90 (1H, d), 7.60 (2H, m), 7.40 (3H, m), 7.30 to 7.10 (4H, m) , 6.62 (2H, m), 6.35 (1H, dd), 6,000 (1H, dd).

  In accordance with the above method, monomers (LM-2) to (LM-4) having the following photoreactive groups were synthesized.

LM-2

¹ H-NMR (CDCl ₃ , δ): 7.90 (1H, d), 7.60 (2H, m), 7.40 (3H, m), 7.20 to 7.10 (4H, m) , 6.60 (1H, d), 6.35 (1H, s), 5.78 (1H, s), 2.05 (3H, s).

LM-3

¹ H-NMR (CDCl ₃ , δ): 7.90 (1H, d), 7.65 (6H, m), 7.58 (2H, m), 7.40 (1H, t), 7.20 -7.10 (4H, m), 6.60 (2H, m), 6.35 (1H, dd), 6,000 (1H, dd).

LM-4

¹ H-NMR (CDCl ₃ , δ): 7.84 (1H, d), 7.55 (2H, d), 7.20-7.10 (4H, m), 6.92 (2H, d) 6.50 (1H, d), 6.35 (1H, s), 5.75 (1H, s), 3.85 (3H, s), 2.05 (3H, s).

Synthesis Example 2 Synthesis of monomer having both polymerizable group and mesogenic group According to the method described in Japanese Patent Application Laid-Open No. 2004-315736 (paragraph numbers 0075 to 0087), it has both the following polymerizable group and mesogenic group. Monomers (MM-1) to (MM-13) were synthesized.

Synthesis example 3
From 9 parts (molar ratio) of the monomer (MM-1) having both a polymerizable group and a mesogenic group and 1 part (molar ratio) of the monomer (LM-1) having a photoreactive group, 2,2-azo By using bisisobutyronitrile as an initiator (2 mol%) and anhydrous N, N-dimethylacetylamide as a solvent, carrying out radical polymerization at 70 ° C. for 10 hours under nitrogen, reprecipitation in methanol and purification. The compound P-1 of the present invention was synthesized.
The weight average molecular weight of P-1 measured by gel permeation chromatography (GPC) was 14,000. The glass transition temperature (Tg) was 40 ° C. by differential scanning calorimetry (DSC measurement, Differential Scanning Calorimetry).

Synthesis example 4
Monomers (MM-1) were changed to MM-2 to MM-13, and others were carried out in the same manner as in Synthesis Example 3 to synthesize compounds P-2 to P-13.

Example 1 Production of Optically Anisotropic Film 3 g of the polymer used in the present invention synthesized in the above synthesis example was dissolved in 10 g of tetrahydrofuran, and insoluble matter was filtered with a polytetrafluoroethylene filter having a pore diameter of 0.45 μm. Was applied to prepare a coating solution. A glass substrate having a thickness of 1 mm was used as a support, and the prepared coating solution was applied onto the support by a spin coating method. After drying for 120 seconds at room temperature, the light emitted from the ultraviolet light emitted from the UV irradiator (HOCANDO OPTRONICS, EXECURE3000) is converted into linearly polarized light through the polarizing plate and perpendicular to the support The film was irradiated with an intensity of 100 mW / cm ² (365 nm) from the direction of 300 seconds to produce a photoisomer film on a glass substrate. At this time, the thickness of the optically anisotropic film was 2.0 μm.
On this optically anisotropic film, a 1% by mass photoacid generator (Chiba, UVI-6974) in methanol is applied, and then emitted from an ultraviolet irradiator (HOYA CANDEO OPTRONICS, EXECURE3000). Ultraviolet light was irradiated for 120 seconds at an intensity of 260 mW / cm ² (365 nm) from a direction perpendicular to the support to produce an optically anisotropic film of the present invention.

  In the same manner as in Example 1, an optically anisotropic film comparative example 1 comprising the following compounds was prepared and evaluated. In the following compounds, x represents 0.1 and y represents 0.9.

Example 2 Evaluation of Optical Anisotropy and Evaluation of Light Durability by Irradiation with Crossed Polarization In this specification, Re (λ) represents in-plane retardation (front retardation) at wavelength λ. The front retardation Re at 589 nm of the obtained film was measured by making light of wavelength λ nm incident in the film normal direction in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).
Next, for the optically anisotropic film thus produced, the light emitted from the ultraviolet light emitted from the ultraviolet irradiator (EXECURE3000, manufactured by HOYA CANDEO OPTRONICS) is converted into linearly polarized light through the polarizing plate. The sample was irradiated for 1200 seconds at an intensity of 100 mW / cm ² (365 nm) from a direction perpendicular to the support. The polarization direction at this time was irradiated in an orthogonal direction with respect to the case where the optical anisotropy was exhibited, and the front retardation Re at 589 nm was measured with KOBRA 21ADH (manufactured by Oji Scientific Instruments).
These results are shown in Table 1. As a result, it became clear that the optically anisotropic film of the present invention has higher light stability with respect to irradiation of orthogonally polarized light as compared with Comparative Example 1.

Example 3 Evaluation of Thermal Durability The optically anisotropic film produced in Examples 1 and 2 was allowed to stand at 150 ° C. for 10 minutes, and then the front retardation Re at 589 nm was measured using KOBRA 21ADH (Oji Scientific Instruments Co., Ltd.). )) And the thermal stability was evaluated.
These results are shown in Table 2. As a result, it was revealed that the optically anisotropic film of the present invention has high thermal stability as compared with Comparative Example 1.

According to the present invention, an optically anisotropic film having excellent production suitability and improved stability can be provided. In particular, in the present invention, it is possible to control the refractive index anisotropy more precisely by separating a photoreactive group and a mesogenic group that greatly affects optical properties, and the orientation of the mesogenic group can be fixed by polymerization. Thus, an optically anisotropic film excellent in optical properties and stability can be obtained.
The optically anisotropic film of the present invention has a relational expression of nx>nz> ny, where nx is the maximum refractive index in the plane direction, ny is the minimum refractive index in the plane direction, and nz is the refractive index in the thickness direction. It can be applied to an optical compensation film for VA mode or IPS mode.

Claims (14)

  The composition containing the high molecular polymer which contains the repeating unit which has both a polymeric group and a mesogenic group, and the repeating unit which has a photoreactive group as a structural unit. The composition according to claim 1, wherein the repeating unit having both the polymerizable group and the mesogenic group is a repeating unit represented by the following general formula (1).
General formula (1)

(In the formula, R ¹ represents a hydrogen atom or a substituent, S ¹ and S ² each independently represents a divalent linking group, M represents a mesogenic group, and P ¹ represents a polymerizable group.)   The composition according to claim 1 or 2, wherein the polymerizable group is a cationic polymerizable group.   The composition according to claim 1 or 2, wherein the polymerizable group is a cyclic ether group, an oxetanyl group or a vinyl ether group. The composition of any one of Claims 1-4 whose repeating unit which has the said photoreactive group is a repeating unit represented by following General formula (2).
General formula (2)

(Wherein R ¹ represents a hydrogen atom or a substituent, Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group), and Ar ¹ and Ar ² are each Independently represents an aromatic ring having 1 to 10 carbon atoms, Ar ¹ and Ar ² may each have a substituent, and n represents an integer of 1 to 3). The composition according to any one of claims 1 to 4, wherein the repeating unit having the photoreactive group is a repeating unit represented by the following general formula (3).
General formula (3)

(Wherein R ¹ represents a hydrogen atom or a substituent, R ³ represents a substituent, Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group); Ar ³ represents a benzene ring, a furan ring or a naphthalene ring, which may have a substituent, and m represents an integer of 0 to 4.)   An optically anisotropic film obtained by causing the composition according to any one of claims 1 to 6 to exhibit optical anisotropy by light irradiation and then crosslinking the polymerizable group.   The polarizing plate which has a polarizer and the protective film provided in the at least single side | surface of this polarizer, and this protective film has the optically anisotropic film of Claim 7.   A liquid crystal display device comprising the optically anisotropic film according to claim 7 or the polarizing plate according to claim 8.   A step of forming a composition comprising a repeating unit having both a polymerizable group and a mesogenic group and a polymer containing a repeating unit having a photoreactive group as a constituent unit, and the composition formed in the form of a film A method for producing an optically anisotropic film, comprising a step of irradiating a product with light, a step of applying a crosslinking polymerization initiator to the composition irradiated with light, and a step of crosslinking a polymerizable group.   The method for producing an optically anisotropic film according to claim 10, wherein the crosslinking polymerization initiator is a photoacid generator.   The method for producing an optically anisotropic film according to claim 10, comprising a step of performing a heat treatment after the light irradiation step.   The method for producing an optically anisotropic film according to any one of claims 10 to 12, wherein in the step of forming the film, the film is formed by spraying a solution containing the composition. A polymer comprising a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2) as constituent units.
General formula (1)

(In the formula, R ¹ represents a hydrogen atom or a substituent, S ¹ and S ² each independently represents a divalent linking group, M represents a mesogenic group, and P ¹ represents a polymerizable group.)
General formula (2)

(Wherein R ¹ represents a hydrogen atom or a substituent, Y ¹ represents an oxygen atom or —NR ² — (R ² represents a hydrogen atom or an alkyl group), and Ar ¹ and Ar ² are each Independently represents an aromatic ring having 1 to 10 carbon atoms, Ar ¹ and Ar ² may each have a substituent, and n represents an integer of 1 to 3).