JP2014034631A - Photo-aligning retardation agent, and retardation film, optical film and display element obtained from the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retardation agent from which a retardation film having desired optical characteristics can be made without requiring a liquid crystal alignment layer, to provide a retardation film from the above agent, and to provide a retardation agent that allows use of an environmentally-friendly solvent having low toxicity.SOLUTION: The photo-aligning retardation agent contains a polymer having a structural unit expressed by formula (1a) or the like in a predetermined molar ratio. In formula (1a), Arepresents any divalent group selected from 1,4-phenylene, pyridine-2,5-diyl, naphthalene-2,6-diyl and biphenyl-4,4'-diyl, which may have a specified substituent; R, R, Z, W, Weach represent a specified functional group; a represents an integer of 1 to 3; and p represents an integer of 1 to 12.

Description

  The present invention relates to a photo-alignment phase difference agent, a phase difference film using the phase difference agent, and an optical film and a display element using the phase difference film. More specifically, a photo-alignable phase difference agent capable of producing a phase difference film having a desired optical characteristic without requiring a liquid crystal alignment film, and a phase difference film using the phase difference agent is applied to optical applications, particularly a liquid crystal. It is suitable for optical compensation films and retardation films in displays, patterned retardation films used for passive glasses 3D display, and the like.

  Liquid crystal display elements are used in various liquid crystal display devices such as monitors for notebook computers and desktop computers, video camera viewfinders, projection displays, and televisions. Furthermore, it is also used as an optoelectronic-related element such as an optical printer head, an optical Fourier transform element, or a light valve. As a conventional liquid crystal display element, a display element using nematic liquid crystal is mainly used, and the alignment direction of the liquid crystal in the vicinity of one substrate and the alignment direction of the liquid crystal in the vicinity of the other substrate are twisted at an angle of 90 °. TN (Twisted Nematic) mode, STN (Super Twisted Nematic) mode in which the orientation direction is usually twisted at an angle of 180 ° or more, and a so-called TFT (Thin-Film-Transistor) mode liquid crystal display element using a thin film transistor It has become.

  However, these liquid crystal display elements have a narrow viewing angle for properly recognizing an image, and when viewed from an oblique direction, luminance and contrast may be reduced, and luminance inversion may occur in a halftone. In recent years, this viewing angle problem has been caused by a TN liquid crystal display element using an optical compensation film, an MVA (Multi-domain Vertical Alignment) mode (see Patent Document 1) or a horizontal alignment and a technology of a protruding structure. This is improved by an electric field type IPS (In-Plane Switching) mode (see Patent Document 2).

  The development of the technology of the liquid crystal display element is achieved not only by simply improving these driving methods and element structures but also by improving members used for the display element. Among the components used in display elements, optical compensation films and retardation films are one of the important factors related to image display quality in order to improve the contrast of image display devices and expand the viewing angle range. As the quality of display elements increases, it plays an important role year after year. 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 polymerizable liquid crystal compound is used.

  In recent years, with respect to these optical compensation films and retardation films, more precise control of refractive index anisotropy is required in order to further improve the contrast of an image display device and increase the viewing angle range. Under such circumstances, stretched films have a problem that the stretch direction during production is limited and it is difficult to precisely control the refractive index anisotropy.

  In a film obtained by aligning and polymerizing a polymerizable liquid crystal compound, the polymerizable liquid crystal compound exhibits optical anisotropy in a liquid crystal state, and the alignment is fixed by polymerization. Examples of the fixed alignment state of the polymer include homogeneous (horizontal alignment), tilt (tilt alignment), homeotropic (vertical alignment), and twist (twist alignment). By controlling the orientation of these polymerizable liquid crystal compounds, precise refractive index anisotropy can be controlled.

  Furthermore, a passive glasses type 3D display has been put to practical use as one type of 3D display. In this 3D display, a phase difference plate is mounted on a liquid crystal display panel. As this phase difference plate, a patterned phase difference plate produced by aligning a polymerizable liquid crystal compound on a liquid crystal alignment film that has been subjected to alignment treatment by a photo-alignment method has been studied.

  However, an optical compensation film or a retardation film made of a polymerizable liquid crystal compound needs to align the polymerizable liquid crystal compound in order to develop desired optical characteristics. In general, there is a problem that a liquid crystal alignment film is required in order to apply a polymerizable liquid crystal compound on a liquid crystal alignment film that has been subjected to an alignment treatment and control the alignment.

  Recently, a retardation film that irradiates liquid crystal polymer with light to control molecular orientation has been proposed (see Patent Documents 3 to 6). The liquid crystalline polymer has a photosensitive group that reacts when irradiated with light, whereby the alignment axis can be controlled. Therefore, it is possible to produce a retardation film without using an alignment film. In addition, the retardation film can be three-dimensionally oriented, which has been difficult to realize with conventional stretched films and polymerizable liquid crystal materials (see Patent Document 5 or 6). In order to produce a retardation film using such a polymer, first, the polymer is dissolved in a solvent, the solution is applied to a substrate, dried, irradiated with linearly polarized light, and heated. . As a solvent for dissolving the polymer in such a process, a solvent having as low a toxicity and environmental load as possible is desired. However, the polymers described in Patent Documents 3 to 6 have poor solubility and have a relatively high toxicity and environmental load. It has a problem of using a solvent.

  In addition, plastics such as polyethylene terephthalate (PET), triacetyl cellulose (TAC), and cyclic olefin polymers may be used for substrates of optical compensation films and retardation films. Since such a plastic substrate has lower solvent resistance than glass, it is necessary to use a solvent that does not erode (dissolve or swell) the substrate.

Japanese Patent No. 2947350 Japanese Patent No. 2940354 JP 2008-276149 A Japanese Patent No. 4636353 JP 2003-307619 A JP 2008-50440 A

  The objective of this invention is providing the phase difference film using the phase difference agent which can produce the phase difference film which does not require a liquid crystal aligning film, and has a desired optical characteristic, and this phase difference agent. Furthermore, another object of the present invention is to provide a retardation agent that enables the use of a solvent having as low toxicity and environmental burden as possible when forming a retardation film.

As a result of diligent research and development, the present inventors solved the above problem by using a photo-alignment phase difference agent composed of a polymer having a photosensitive group having a specific photo-alignment property and liquid crystallinity. I found out. In addition, by using the photo-alignment phase difference agent, it is possible to use a solvent having low toxicity and low environmental load and to provide a phase difference film without using a liquid crystal alignment film. That is, the present invention is as follows.
[1] The structural unit represented by the formula (1a) and the structural unit represented by the formula (1b) are included at a molar ratio m: n.
M: n includes a polymer (1) satisfying the relationship of 0.1 ≦ m ≦ 1, 0 ≦ n ≦ 0.9, m + n = 1:

式（１ａ）中、Ｒ¹は水素またはメチルであり；Ｒ^1'は炭素数１〜１０のアルキルであり；Ａ¹はそれぞれ独立して１，４−フェニレン、ピリジン−２，５−ジイル、ナフタレン−２，６−ジイルおよびビフェニル−４，４’−ジイルから選ばれるいずれかの二価基であり、該二価基において、任意の水素はフッ素、塩素、シアノ、ヒドロキシ、ホルミル、アセトキシ、アセチル、トリフルオロアセチル、ジフルオロメチル、トリフルオロメチル、炭素数１〜５のアルキルまたは炭素数１〜５のアルコキシで置き換えられてもよく；Ｚ¹はそれぞれ独立して単結合、−ＣＯＯ−、−ＣＨ＝ＣＨ−ＣＯＯ−、−ＣＨ₂ＣＨ₂−ＣＯＯ−、−ＣＨ₂Ｏ−、−ＣＦ₂Ｏ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−（ＣＨ₂）₄−または−ＣＨ₂ＣＨ₂−であり；ａは１〜３の整数であり；Ｗ¹およびＷ^1'はそれぞれ独立して水素、フッ素、塩素、トリフルオロメチル、炭素数１〜５のアルキルまたは炭素数１〜５のアルコキシであり；ｐは１〜１２の整数である；

In formula (1a), R ¹ is hydrogen or methyl; R ^{1 ′} is alkyl having 1 to 10 carbons; A ¹ is each independently 1,4-phenylene, pyridine-2,5-diyl, Any divalent group selected from naphthalene-2,6-diyl and biphenyl-4,4′-diyl, in which any hydrogen is fluorine, chlorine, cyano, hydroxy, formyl, acetoxy, Acetyl, trifluoroacetyl, difluoromethyl, trifluoromethyl, alkyl having 1 to 5 carbons or alkoxy having 1 to 5 carbons may be substituted; each Z ¹ independently represents a single bond, —COO—, — CH═CH—COO—, —CH ₂ CH ₂ —COO—, —CH ₂ O—, —CF ₂ O—, —CONH—, —NHCO—, — (CH ₂ ) ₄ — or —CH ₂ CH ₂ — And A is an integer of 1 to 3; W ¹ and W ^{1 ′} are each independently hydrogen, fluorine, chlorine, trifluoromethyl, alkyl having 1 to 5 carbons or alkoxy having 1 to 5 carbons; p is an integer from 1 to 12;

式（１ｂ）中、Ｒ²は水素またはメチルであり；Ａ²はそれぞれ独立して１，４−フェニレン、ピリジン−２，５−ジイル、ナフタレン−２，６−ジイルおよびビフェニル−４，４’−ジイルから選ばれるいずれかの二価基であり、該二価基において、任意の水素はフッ素、塩素、シアノ、ヒドロキシ、ホルミル、アセトキシ、アセチル、トリフルオロアセチル、ジフルオロメチル、トリフルオロメチル、炭素数１〜５のアルキルまたは炭素数１〜５のアルコキシで置き換えられてもよく；Ｚ²はそれぞれ独立して単結合、−ＣＯＯ−、−ＣＨ＝ＣＨ−ＣＯＯ−、−ＣＨ₂ＣＨ₂−ＣＯＯ−、−ＣＨ₂Ｏ−、−ＣＦ₂Ｏ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−（ＣＨ₂）₄−または−ＣＨ₂ＣＨ₂−であり；ｂは０〜２の整数であり；ｑは１〜１２の整数である。

In formula (1b), R ² is hydrogen or methyl; A ² is each independently 1,4-phenylene, pyridine-2,5-diyl, naphthalene-2,6-diyl and biphenyl-4,4 ′. -Any divalent group selected from diyl, in which any hydrogen is fluorine, chlorine, cyano, hydroxy, formyl, acetoxy, acetyl, trifluoroacetyl, difluoromethyl, trifluoromethyl, carbon May be substituted with alkyl of 1 to 5 or alkoxy of 1 to 5 carbons; each Z ² is independently a single bond, —COO—, —CH═CH—COO—, —CH ₂ CH ₂ —COO. _{-, - CH 2 O -,} - CF 2 O -, - CONH -, - NHCO -, - (CH 2) 4 - or -CH ₂ CH ₂ - a and; b is an integer from 0 to 2; q 1-12 Is an integer.

[2] In the structural unit represented by the formula (1a), R ^{1 ′} is alkyl having 1 to 5 carbon atoms; A ¹ is independently 1,4-phenylene, naphthalene-2,6-diyl. And biphenyl-4,4′-diyl, in which any hydrogen is fluorine, trifluoromethyl, alkyl having 1 to 3 carbons or 1 to 3 carbons. Z ¹ is each independently —COO— or —CH ₂ CH ₂ —COO—; a is 1 or 2; W ¹ and W ^{1 ′} are each independently Hydrogen, fluorine, alkyl having 1 to 3 carbons or alkoxy having 1 to 3 carbons;
In the structural unit represented by the formula (1b), each A ² is independently any one divalent selected from 1,4-phenylene, naphthalene-2,6-diyl and biphenyl-4,4′-diyl. In the divalent group, any hydrogen may be replaced by fluorine, trifluoromethyl, alkyl having 1 to 3 carbons or alkoxy having 1 to 3 carbons; each Z ² is independently- COO- or -CH ₂ CH ₂ -COO- a and; characterized in that b is 0 or 1, photoalignable retardation agent according to [1].

[3] The photo-alignment property according to [1] or [2], wherein m and n satisfy a relationship of 0.35 <m ≦ 1, 0 ≦ n <0.65, m + n = 1. Retardant.
[4] The photoalignable phase difference agent according to any one of [1] to [3], wherein the polymer (1) has a weight average molecular weight of 1,000 to 500,000.
[5] The coating film formed from the photo-alignment phase difference agent according to any one of [1] to [4] is irradiated with light containing linearly polarized light, and further heated to irradiate the optical difference. A retardation film obtained by imparting a directivity.
[6] An optical film produced using the retardation film according to [5].
[7] A display element produced using the optical film according to [6].

  The present invention relates to a photo-alignment phase difference agent using a photoreactive liquid crystal polymer, and according to the photo-alignment phase difference agent according to the present invention, when forming a phase difference film, toxicity and environmental load are relatively low. Since a low solvent can be used, a retardation film can be provided without using a solvent having high toxicity or high environmental load.

  In addition, the retardation film obtained from the photo-alignment phase difference agent of the present invention does not require the use of a liquid crystal alignment film that has been used in a phase difference film using a conventional polymerizable liquid crystal material. According to the photo-alignment phase difference agent, a phase difference film can be obtained without requiring a liquid crystal alignment agent. Therefore, according to the photo-alignable phase difference agent of the present invention, the step of forming the liquid crystal alignment film can be omitted, thereby simplifying the manufacturing process of the retardation film and reducing the manufacturing cost. It becomes possible.

  The retardation film is required to exhibit desired retardation (retardation), transparency, heat resistance, retardation stability, and the like. The retardation can be adjusted by birefringence (Δn) and the thickness of the film. If the birefringence is large, the thickness of the film can be reduced. Furthermore, it is possible to produce a retardation film having various optical characteristics by controlling the orientation axis. In particular, since the photoalignable phase difference agent of the present invention can be controlled by light irradiation, special orientation such as three-dimensional orientation is possible. Moreover, lamination | stacking of retardation film also becomes easy.

The present invention will be described in detail.
[Photo-alignment phase difference agent]
In the present invention, the photo-alignment phase difference agent contains at least one polymer exhibiting liquid crystallinity and having a photoreactive group (photosensitive group) (hereinafter referred to as “photosensitive liquid crystal polymer”). Here, in the present invention, the polymer (1) described later is used as such a photosensitive liquid crystal polymer.

  Here, in this specification, a polymer that does not exhibit liquid crystallinity and has a photoreactive group is referred to as a photosensitive polymer. The photosensitive polymer is, for example, a compound that causes at least one of a photoisomerization reaction, a photodimerization reaction, and a photolysis reaction by irradiation with plane polarized light. The photosensitive polymer is preferably a compound that causes a photoisomerization reaction or a photodimerization reaction by light irradiation, and particularly preferably a compound that causes a photodimerization reaction. The photosensitive polymer preferably has a weight average molecular weight of about 1,000 to 500,000.

  Among the photosensitive polymers, a compound that undergoes a photoisomerization reaction refers to a compound that undergoes stereoisomerization or structural isomerization by the action of light. Examples of the photoisomerization compound include cinnamic acid compounds (K. Ichimura et al., Macromolecules, 30, 903 (1997)) and azobenzene compounds (K. Ichimura et al., Mol. Cryst. Liq. Cryst., 298, 221 (1997)), hydrazono-β-ketoester compounds (S. Yamamura et al., Liquid Crystals, vol. 13, No. 2, page 189 (1993)), stilbene compounds (JG Victor and JM Torkelson, Macromolecules, 20 , 2241 (1987)), and spiropyran compounds (K. Ichimura et al., Chemistry Letters, page 1063 (1992); K. Ichimura et al., Thin Solid Films, vol. 235, page 101 (1993)). It is done. Moreover, the compound which has these frame | skeleton in a polymer principal chain or a polymer side chain is also contained. Among these, a photoisomerized compound containing a double bond structure consisting of —CH═CH— or —N═N— is preferable.

  Among the photosensitive polymers, a compound that causes a photodimerization reaction refers to a compound that undergoes an addition reaction between two groups upon irradiation with light to cyclize. Examples of photodimerization compounds include cinnamic acid derivatives (M. Schadt et al., J. Appl. Phys., Vol. 31, No. 7, page 2155 (1992)) and coumarin derivatives (M. Schadt et al., Nature., Vol. 381, page 212 (1996)), chalcone derivatives (Toshihiro Ogawa et al., Proceedings of Liquid Crystal Panel Discussion, 2AB03 (1997)), benzophenone derivatives (YK Jang et al., SID Int. Symposium Digest, P -53 (1997)). Moreover, the compound which has the derivative which has these frame | skeleton in a polymer principal chain or a side chain is also contained. Among them, a polymer having a cinnamic acid derivative or a coumarin derivative skeleton in the side chain is preferable, and a polymer having a cinnamic acid derivative skeleton in the side chain (side chain polymer) is more preferable.

  A polymer that exhibits liquid crystallinity but does not have a photoreactive group is called a liquid crystal polymer. A retardation film using a liquid crystalline polymer has also been proposed (Japanese Patent Application Laid-Open No. 2004-123882). However, a retardation film using a liquid crystalline polymer needs to use a liquid crystal alignment film as well as a retardation film using a polymerizable liquid crystal.

As the photosensitive liquid crystal polymer used for the photo-alignment phase difference agent, a cinnamic acid derivative is preferable because of high photoreaction sensitivity, transparency, ease of production, and the like.
In the description of the present specification, the term “arbitrary” used when describing symbols of chemical formulas means “not only the position of an element (or functional group) but also the number thereof can be freely selected”. And for example, the expression “any A may be replaced by B, C or D” means that one A may be replaced by any one of B, C and D, and any two of A May be replaced with two of B, C or D, and may be replaced with B and C, B and D, or C and D. That is, when a certain functional group has one or more A, and there is an expression “any A may be replaced by B, C or D” for the functional group, it exists on the functional group It means that any one selected from B, C and D (here, the selected species is X) may be arranged instead of at least one of A. Here, when a plurality of A are substituted, a plurality of Xs arranged in place of A may be the same or different from each other. However, the number of Xs arranged in place of A is one for one A. Accordingly, when any —CH ₂ — may be replaced by —O—, such a replacement that results in the bonding group —O—O— is not included.

  In addition, having one polymerizable group may be referred to as monofunctional. In addition, having two or more polymerizable groups may be referred to as polyfunctional or a designation according to the number of polymerizable groups (eg, bifunctional in the case of having two polymerizable groups).

In addition, a compound in which an arbitrary functional group is introduced into an A compound or an atom or the like is replaced may be referred to as a derivative or an A derivative.
The photosensitive liquid crystal polymer may be simply abbreviated as a polymer. Further, the liquid crystal display element may be abbreviated as a display element, and the liquid crystal alignment film may be abbreviated as an alignment film.

Hereinafter, the polymer (1) used as the photosensitive liquid crystal polymer constituting the photoalignable phase difference agent of the present invention will be described.
Polymer (1)
The photo-alignment phase difference agent of the present invention is
Including the polymer (1) having the structural unit represented by the formula (1a) as an essential structural unit:

式（１ａ）中、Ｒ¹は水素またはメチルであり；Ｒ^1'は炭素数１〜１０のアルキルであり；Ａ¹はそれぞれ独立して１，４−フェニレン、ピリジン−２，５−ジイル、ナフタレン−２，６−ジイルおよびビフェニル−４，４’−ジイルから選ばれるいずれかの二価基であり、該二価基において、任意の水素はフッ素、塩素、シアノ、ヒドロキシ、ホルミル、アセトキシ、アセチル、トリフルオロアセチル、ジフルオロメチル、トリフルオロメチル、炭素数１〜５のアルキルまたは炭素数１〜５のアルコキシで置き換えられてもよく；Ｚ¹はそれぞれ独立して単結合、−ＣＯＯ−、−ＣＨ＝ＣＨ−ＣＯＯ−、−ＣＨ₂ＣＨ₂−ＣＯＯ−、−ＣＨ₂Ｏ−、−ＣＦ₂Ｏ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−（ＣＨ₂）₄−または−ＣＨ₂ＣＨ₂−であり；ａは１〜３の整数であり；Ｗ¹およびＷ^1'はそれぞれ独立して水素、フッ素、塩素、トリフルオロメチル、炭素数１〜５のアルキルまたは炭素数１〜５のアルコキシであり；ｐは１〜１２の整数である。

In formula (1a), R ¹ is hydrogen or methyl; R ^{1 ′} is alkyl having 1 to 10 carbons; A ¹ is each independently 1,4-phenylene, pyridine-2,5-diyl, Any divalent group selected from naphthalene-2,6-diyl and biphenyl-4,4′-diyl, in which any hydrogen is fluorine, chlorine, cyano, hydroxy, formyl, acetoxy, Acetyl, trifluoroacetyl, difluoromethyl, trifluoromethyl, alkyl having 1 to 5 carbons or alkoxy having 1 to 5 carbons may be substituted; each Z ¹ independently represents a single bond, —COO—, — CH═CH—COO—, —CH ₂ CH ₂ —COO—, —CH ₂ O—, —CF ₂ O—, —CONH—, —NHCO—, — (CH ₂ ) ₄ — or —CH ₂ CH ₂ — And A is an integer of 1 to 3; W ¹ and W ^{1 ′} are each independently hydrogen, fluorine, chlorine, trifluoromethyl, alkyl having 1 to 5 carbons or alkoxy having 1 to 5 carbons; p is an integer of 1-12.

Here, in the present invention, A ¹ is selected from 1,4-phenylene, naphthalene-2,6-diyl, and biphenyl-4,4′-diyl from the viewpoints of high liquid crystallinity and ease of production. Such a divalent group is preferred. In this case, preferred substituents that these divalent groups may have include fluorine, trifluoromethyl, alkyl having 1 to 3 carbon atoms, and alkoxy having 1 to 3 carbon atoms.

Z ¹ is preferably —COO— or —CH ₂ CH ₂ —COO— from the viewpoint of high liquid crystallinity and high solubility.
W ¹ and W ^{1 ′} are preferably hydrogen, fluorine, alkyl having 1 to 3 carbon atoms or alkoxy having 1 to 3 carbon atoms, and R ^{1 ′} is alkyl having 1 to 5 carbon atoms. A is preferably an integer of 1 or 2.

The polymer (1) constituting the photoalignable phase difference agent of the present invention may contain one type of structural unit represented by the formula (1a), or may contain two or more types. Good.
Moreover, although the polymer (1) which comprises the photo-alignment phase difference agent of this invention may have only the structural unit represented by Formula (1a), the structure represented by Formula (1a) In addition to the unit, if necessary, it may further have a structural unit represented by the formula (1b):

式（１ｂ）中、Ｒ²は水素またはメチルであり；Ａ²はそれぞれ独立して１，４−フェニレン、ピリジン−２，５−ジイル、ナフタレン−２，６−ジイルおよびビフェニル−４，４’−ジイルから選ばれるいずれかの二価基であり、該二価基において、任意の水素はフッ素、塩素、シアノ、ヒドロキシ、ホルミル、アセトキシ、アセチル、トリフルオロアセチル、ジフルオロメチル、トリフルオロメチル、炭素数１〜５のアルキルまたは炭素数１〜５のアルコキシで置き換えられてもよく；Ｚ²はそれぞれ独立して単結合、−ＣＯＯ−、−ＣＨ＝ＣＨ−ＣＯＯ−、−ＣＨ₂ＣＨ₂−ＣＯＯ−、−ＣＨ₂Ｏ−、−ＣＦ₂Ｏ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−（ＣＨ₂）₄−または−ＣＨ₂ＣＨ₂−であり；ｂは０〜２の整数であり；ｑは１〜１２の整数である。

In formula (1b), R ² is hydrogen or methyl; A ² is each independently 1,4-phenylene, pyridine-2,5-diyl, naphthalene-2,6-diyl and biphenyl-4,4 ′. -Any divalent group selected from diyl, in which any hydrogen is fluorine, chlorine, cyano, hydroxy, formyl, acetoxy, acetyl, trifluoroacetyl, difluoromethyl, trifluoromethyl, carbon May be substituted with alkyl of 1 to 5 or alkoxy of 1 to 5 carbons; each Z ² is independently a single bond, —COO—, —CH═CH—COO—, —CH ₂ CH ₂ —COO. _{-, - CH 2 O -,} - CF 2 O -, - CONH -, - NHCO -, - (CH 2) 4 - or -CH ₂ CH ₂ - a and; b is an integer from 0 to 2; q 1-12 Is an integer.

Here, in the present invention, similarly to A ¹ in formula (1a), A ² is any one selected from 1,4-phenylene, naphthalene-2,6-diyl and biphenyl-4,4′-diyl. A valent group is preferred. Also in this case, preferred substituents that these divalent groups may have include fluorine, trifluoromethyl, alkyl having 1 to 3 carbon atoms, and alkoxy having 1 to 3 carbon atoms.
Z ² is preferably —COO— or —CH ₂ CH ₂ —COO—.
Further, b is preferably an integer of 0 or 1.

  In the case where the polymer (1) constituting the photoalignable phase difference agent of the present invention includes the structural unit represented by the formula (1b), the structural unit represented by the formula (1b) is included alone. Or two or more of them may be included.

  In the present invention, as described later, the coating film formed from the photoalignable retardation agent containing the polymer (1) is irradiated with light containing linearly polarized light, and then heated further to obtain a retardation film. it can. Here, when the polymer (1) constituting the photoalignable phase difference agent of the present invention includes not only the structural unit represented by the formula (1a) but also the structural unit represented by the formula (1b), This light irradiation can be performed with a lower dose, and tends to be more advantageous in terms of practicality.

And the molar ratio of the structural unit represented by Formula (1a) and the structural unit represented by Formula (1b) which comprises the polymer (1) which comprises the photo-alignment phase difference agent of this invention is m: n. , M and n satisfy the relationship of 0.1 ≦ m ≦ 1, 0 ≦ n ≦ 0.9, and m + n = 1. Here, when m = 1 and n = 0, the polymer (1) includes the structural unit represented by the formula (1a) but does not include the structural unit represented by the formula (1b). On the other hand, in the case of 0.1 ≦ m <1, 0 <n ≦ 0.9, the polymer (1) includes both the structural unit represented by the formula (1a) and the structural unit represented by the formula (1b). Will be included.
In the present invention, m and n are m + n = 1, preferably 0.35 <m ≦ 1, 0 ≦ n <0.65, more preferably 0.4 ≦ m ≦ 1, 0 ≦ n ≦. 0.6.

As the polymer (1) used in the photo-alignment phase difference agent of the present invention,
As a structural unit represented by the formula (1a),
R ^{1 ′} is alkyl having 1 to 5 carbons; A ¹ is independently any one selected from 1,4-phenylene, naphthalene-2,6-diyl and biphenyl-4,4′-diyl a divalent group, in said divalent group, any hydrogen fluorine, trifluoromethyl, may be replaced by alkyl or alkoxy of 1 to 3 carbon atoms of 1 to 3 carbon atoms; is Z ¹ each independently Te -COO- or -CH ₂ CH ₂ -COO- a and; a is the integer 1 or 2; W ¹ and W ^{1 'are} each independently hydrogen, fluorine, alkyl or carbon with 1 to 3 carbon atoms A structural unit which is alkoxy of formulas 1-3;
As a structural unit represented by the formula (1b),
A ² is each independently any divalent group selected from 1,4-phenylene, naphthalene-2,6-diyl and biphenyl-4,4′-diyl, and in the divalent group, Hydrogen may be replaced by fluorine, trifluoromethyl, alkyl having 1 to 3 carbons or alkoxy having 1 to 3 carbons; each Z ² is independently —COO— or —CH ₂ CH ₂ —COO—. Yes; a structural unit in which b is an integer of 0 or 1,
A polymer having a molar ratio m: n satisfying the relationship of 0.35 <m ≦ 1, 0 ≦ n <0.65, m + n = 1 is preferably used.

  Hereinafter, preferred specific examples of the structural unit represented by the formula (1a) and the structural unit represented by the formula (1b) constituting the polymer (1) will be shown, but the present invention is limited by these specific examples. It is not something. The polymer (1) preferably has liquid crystallinity. Here, in the present specification, the term “liquid crystallinity” is not limited to the meaning of having a liquid crystal phase, and even when it does not have a liquid crystal phase itself, it is mixed with other liquid crystal compounds. , Is also used as a term encompassing the meaning of having properties that can be used as a component of a liquid crystal composition.

  Specific examples of the structural unit represented by the formula (1a) include the following.

また、式（１ｂ）で表される構成単位の具体例として、以下のものが挙げられる。

Moreover, the following are mentioned as a specific example of the structural unit represented by Formula (1b).

そして、ポリマー（１）における、式（１ａ）で表される構成単位についての例示構造（１ａ−１）〜（１ａ−１６）と、式（１ｂ）で表される構成単位についての例示構造（１ｂ−１）〜（１ｂ−１１）との好適な組み合わせ例を表１に示す。すなわち、ポリマー（１）の好適な例として、表１記載の組み合わせ例（１−１）〜（１−１９）に示した式（１ａ）で表される構成単位と式（１ｂ）で表される構成単位とを有するものが挙げられるが、これらに限定されるものではない。ここで、表１において、例えば、組み合わせ例（１−１）は、式（１ａ）で表される構成単位として式（１ａ−１）で表される構成単位を有するが、式（１ｂ）で表される構成単位は含まないポリマーを示している。また、組み合わせ例（１−５）は、式（１ａ）で表される構成単位として式（１ａ−２）で表される構成単位と式（１ａ−５）で表される構成単位を有するが、式（１ｂ）で表される構成単位は含まないポリマーを示している。さらに、組み合わせ例（１−８）は、式（１ａ）で表される構成単位として式（１ａ−２）で表される構成単位を有し、式（１ｂ）で表される構成単位として式（１ｂ−１）で表される構成単位を有するポリマーを示している。

And in the polymer (1), exemplary structures (1a-1) to (1a-16) for the structural unit represented by the formula (1a) and an exemplary structure for the structural unit represented by the formula (1b) ( Examples of suitable combinations with 1b-1) to (1b-11) are shown in Table 1. That is, as a suitable example of the polymer (1), the structural unit represented by the formula (1a) shown in the combination examples (1-1) to (1-19) described in Table 1 and the formula (1b) are used. However, the present invention is not limited to these. Here, in Table 1, for example, the combination example (1-1) has the structural unit represented by the formula (1a-1) as the structural unit represented by the formula (1a), but the formula (1b) The structural unit shown represents a polymer that does not contain. In addition, the combination example (1-5) includes the structural unit represented by the formula (1a-2) and the structural unit represented by the formula (1a-5) as the structural unit represented by the formula (1a). The polymer which does not contain the structural unit represented by Formula (1b) is shown. Furthermore, the combination example (1-8) has a structural unit represented by the formula (1a-2) as a structural unit represented by the formula (1a), and a structural unit represented by the formula (1b) The polymer which has a structural unit represented by (1b-1) is shown.

また、本発明の光配向性位相差剤を構成するポリマー（１）は、式（１ａ）で表される構成単位および式（１ｂ）で表される構成単位のほかに、式（１ａ）で表される構成単位および式（１ｂ）で表される構成単位のいずれでもない他の構成単位（以下、「他の構成単位」）を含有してもよい。

The polymer (1) constituting the photoalignable phase difference agent of the present invention is represented by the formula (1a) in addition to the structural unit represented by the formula (1a) and the structural unit represented by the formula (1b). You may contain the other structural unit (henceforth "other structural unit") which is neither of the structural unit represented and the structural unit represented by Formula (1b).

  This “other structural unit” refers to a structural unit derived from an industrially available monomer capable of radical polymerization reaction, that is, an ethylenically unsaturated divalent monomer contained in an industrially available monomer capable of radical polymerization reaction. A structural unit formed by opening a π bond constituting a polymerization reactive multiple bond such as a heavy bond can be used.

  Hereinafter, a monomer that derives “another structural unit”, that is, a monomer that can form an “other structural unit” by opening a π bond constituting a polymerization-reactive multiple bond such as an ethylenically unsaturated double bond. A specific example is given. The present invention is not limited to these specific examples.

Examples of industrially available monomers capable of forming a radical polymerization reaction that can form this “other structural unit” include compounds having at least one ethylenically unsaturated double bond, and specific examples thereof include (meth) (Meth) acrylic acid such as acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, and benzyl (meth) acrylate or the like Derivatives;
Hydroxyalkyl esters such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate;
monofunctional (meth) acrylate compounds such as ω-carboxypolycaprolactone mono (meth) acrylate, monohydroxyethyl (meth) acrylate phthalate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate;
1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene Glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, ditrimethylolpropane Tetra (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dicyclopentanyl di (meth) acrylate, ethoxylated hydrogenated bisphenol A di (meth) acrylate, ethoxylated bisphenol A di (meth) Acrylate, ethoxylated bisphenol F di (meth) acrylate, ethoxylated bisphenol S di (meth) acrylate, hydroxypropyl di (meth) acrylate, diethylene glycol bishydroxypropyl (meth) acrylate, monohydroxypentaerythritol tri (meth) acrylate, etc. A polyfunctional (meth) acrylate compound of
There are (meth) acrylate compounds having a cyclic ether group such as glycidyl (meth) acrylate, (3-methyl-3-oxetanyl) methyl (meth) acrylate, and (3-ethyl-3-oxetanyl) methyl (meth) acrylate. .

Further, as these compounds, commercially available monofunctional or polyfunctional (meth) acrylate compounds can be used as they are. Specifically, Aronix (registered trademark) M-5400 (monohydroxyethyl acrylate phthalate), M-5700 (2-hydroxy-3-phenoxypropyl acrylate), M-215 (manufactured by Toa Gosei Co., Ltd.) Isocyanuric acid ethyleneoxycide-modified diacrylate), M-220 (tripropylene glycol diacrylate), M-245 {polyethylene glycol (n≈9) diacrylate}, M-305 (pentaerythritol triacrylate), M-309 (trimethylolpropane triacrylate), M-315 (isocyanuric acid ethylene oxide modified triacrylate), M-400 {mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (main component) Things}, the M-450 (pentaerythritol tetraacrylate), the M-8060, and the M-8560;
Biscoat # 295 (trimethylolpropane triacrylate), # 300 (pentaerythritol triacrylate), # 360 (trimethylolpropane ethylene oxide modified triacrylate), and # 400 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) Pentaerythritol tetraacrylate);
KAYARAD (registered trademark) TMPTA (trimethylolpropane triacrylate), PET-30 (pentaerythritol triacrylate), DPHA (dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (main components) manufactured by Nippon Kayaku Co., Ltd. ), D-310 (dipentaerythritol pentaacrylate), D-330, and DPCA-60.

  In the present invention, among the above-mentioned compounds, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, Aronix M-305 manufactured by Toa Gosei Co., Ltd. # 309, M-400, M-450, Biscoat # 295, # 300, # 400, manufactured by Osaka Organic Chemical Industry Co., Ltd., KAYARADTMPTA, DPHA, D manufactured by Nippon Kayaku Co., Ltd. Trifunctional or higher polyfunctional acrylates such as -310 and PET-30 can be preferably used.

These compounds can be used individually by 1 type or in mixture of 2 or more types.
In the polymer (1) used in the present invention, such “other structural unit” is expressed by the total number of moles of the structural unit represented by the formula (1a) and the structural unit represented by the formula (1b). As 100, it can be contained in a proportion of 30 to 1 mol, preferably 10 to 1 mol.

  In the present invention, as the monomer capable of forming the “other structural unit”, in addition to the “industrially available monomer capable of radical polymerization reaction”, if necessary, the term “additive” The “photosensitizer having a polymerizable group” described later in 1) can be further used.

As an aspect which the polymer (1) which has these structural units mentioned above can take,
(I) a homopolymer or copolymer comprising only the structural unit represented by formula (1a);
(Ii) a copolymer having a structural unit represented by the formula (1a) and a structural unit represented by the formula (1b);
(Iii) a copolymer composed of the structural unit represented by the formula (1a) and “other structural unit”;
(Iv) Copolymers composed of the structural unit represented by the formula (1a), the structural unit represented by the formula (1b), and “other structural unit” may be mentioned.

  The weight average molecular weight of the polymer (1) is preferably 1000 or more and 500,000 or less, and more preferably 1000 or more and 100,000 or less. Here, the weight average molecular weight can be measured as a value in terms of polystyrene (PS) using gel permeation chromatography (GPC).

  About the manufacturing method of a polymer (1), it does not specifically limit, The general purpose method currently treated industrially can be utilized. Specifically, vinyl as a constituent monomer, that is, a monomer capable of forming a constituent unit represented by the formula (1a), a monomer capable of forming a constituent unit represented by the formula (1b), and “other constituents” It can be produced by cationic polymerization, radical polymerization, or anionic polymerization using an ethylenically unsaturated double bond contained in each of the monomers capable of forming “units”. Among these, radical polymerization is particularly preferable from the viewpoint of ease of reaction control.

  In the present invention, the polymer (1) includes a monomer capable of forming a structural unit represented by the formula (1a), a monomer capable of forming a structural unit represented by the formula (1b), and a monomer “ A monomer capable of forming the “other structural unit” can be suitably obtained by radical polymerization in the presence of a suitable polymerization initiator.

As the polymerization initiator for radical polymerization, known compounds such as radical thermal polymerization initiators and radical photopolymerization initiators can be used.
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 ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; diacyl peroxides such as acetyl peroxide and benzoyl peroxide; hydrogen peroxide, tert-butyl hydride Hydroperoxides such as oxide and cumene hydroperoxide; Dialkyl peroxides such as di-tert-butyl peroxide, dicumyl peroxide and dilauroyl peroxide; Peroxyketals such as dibutylperoxycyclohexane and peroxy Neodecanoic acid-tert-butyl ester, peroxypivalic acid-tert-butyl ester, peroxy 2-ethylcyclohexane-tert-amyl ester, etc. Alkyl peresters; persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate; and azobisisobutyronitrile, 2,2'-di (2-hydroxyethyl) azobisisobutyronitrile, etc. Of the azo compounds. Such radical thermal polymerization initiators can be used singly or in combination of two or more.

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

  The radical polymerization method is not particularly limited, and an emulsion polymerization method, suspension polymerization method, dispersion polymerization method, precipitation polymerization method, bulk polymerization method, solution polymerization method and the like can be used. The same applies to other polymerization methods, and details thereof are described in “Synthesis of Polymers (Part 1)” (by Takeshi Endo, Kodansha, 2010). An outline of solution polymerization, which is a general radical polymerization method, will be described below.

  The solution polymerization method is a reaction in which polymerization is performed in a solvent using an oil-soluble polymerization catalyst. These organic solvents can be arbitrarily selected within a range suitable for the purpose and effect of the invention. These organic solvents are usually organic compounds having a boiling point in the range of 50 to 200 ° C. under atmospheric pressure, and organic compounds that uniformly dissolve monomers, polymerization process components, and the like are preferable.

  The organic solvent used here should not have an inhibitory action on radical polymerization, and is preferably an aromatic compound such as benzene, toluene, xylene, and ethylbenzene; such as pentane, hexane, heptane, octane, cyclohexane, and cycloheptane. Aliphatic compounds; alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and ethylene glycol; ethers such as dibutyl ether, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, and dioxane; acetone, methyl ethyl ketone, methyl isobutyl Ketones such as ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate, amyl acetate and γ-butyrolactone; It is. These organic solvents can be used alone or in combination of two or more.

  Also, the solution polymerization conditions are not particularly limited, but for example, it is preferable to heat within a temperature range of 50 to 200 ° C. for 10 minutes to 20 hours. Furthermore, in order not to deactivate the generated radicals, it is preferable to purge with an inert gas such as nitrogen not only during solution polymerization but also before the start of solution polymerization.

  A radical polymerization method using a chain transfer agent is particularly effective for controlling the molecular weight of the polymer (1), homogenizing the molecular weight distribution or promoting polymerization. As a result, a polymer having a more uniform molecular weight distribution in a preferable molecular weight range can be obtained.

  As chain transfer agents, β-mercaptopropionic acid, β-mercaptopropionic acid methyl ester, isopropyl mercaptan, octyl mercaptan, decyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, octadecyl mercaptan, thiophenol and p-nonylthiophenol, thiosalicil Mercaptans such as acid, mercaptoacetic acid and mercapto; polyhalogenated alkyls such as carbon tetrachloride, chloroform, butyl chloride, 1,1,1-trichloroethane and 1,1,1-tribromooctane; α-methylstyrene; low active monomers such as α-methylstyrene dimer can be used. The amount of these chain transfer agents used is determined by the activity of the chain transfer agent, the combination of monomers, the solvent, temperature, and other polymerization conditions. Usually, it is about 0.01 mol% to 50 mol% with respect to the total number of moles of monomers used.

Additives When the photo-alignable phase difference agent of the present invention is used for a film such as a retardation film, the resulting film is often not used alone, but in a state where it is formed on a substrate. Used. The retardation film made of the photo-alignment phase difference agent is necessary for optical films and optical display elements such as good orientation, adhesion to the substrate, coating uniformity, chemical resistance, heat resistance, transmittance, and gas barrier properties. Characteristics are required. In order to impart such properties, additives can be further included.

The amount of each additive added is determined according to the required characteristics, but is preferably 0.01 to 10 parts by weight for each component with respect to 100 parts by weight of the polymer (1).
Additives include acrylic, styrene, polyethyleneimine or urethane polymer dispersants, anionic, cationic, nonionic or fluorine surfactants, silicone resin and other coatability improvers, silane cups Adhesion improvers such as ring agents, ultraviolet absorbers such as alkoxybenzophenones, anti-aggregation agents such as sodium polyacrylate, thermal crosslinking agents such as oxirane compounds, melamine compounds or bisazide compounds, and alkali solubility such as organic carboxylic acids There are accelerators. When these additives are used, the total addition amount is preferably 30 to 1 part by weight with respect to 100 parts by weight of the polymer (1).

A photosensitizer can also be used as an additive. Colorless and triplet sensitizers are preferred.
As photosensitizers, aromatic nitro compounds, coumarins (7-diethylamino-4-methylcoumarin, 7-hydroxy-4-methylcoumarin), ketocoumarins, carbonyl biscoumarins, aromatic 2-hydroxyketones, and amino substituted Aromatic 2-hydroxyketone (2-hydroxybenzophenone, mono- or di-p- (dimethylamino) -2-hydroxybenzophenone), acetophenone, anthraquinone, xanthone, thioxanthone, benzanthrone, thiazoline (2-benzoylmethylene-3 -Methyl-β-naphthothiazoline, 2- (β-naphthoylmethylene) -3-methylbenzothiazoline, 2- (α-naphthoylmethylene) -3-methylbenzothiazoline, 2- (4-biphenoylmethylene)- 3-methylbenzothia Phosphorus, 2- (β-naphthoylmethylene) -3-methyl-β-naphthothiazoline, 2- (4-biphenoylmethylene) -3-methyl-β-naphthothiazoline, 2- (p-fluorobenzoylmethylene)- 3-methyl-β-naphthothiazoline), oxazoline (2-benzoylmethylene-3-methyl-β-naphthoxazoline, 2- (β-naphthoylmethylene) -3-methylbenzoxazoline, 2- (α-naphthoylmethylene) ) -3-methylbenzoxazoline, 2- (4-biphenoylmethylene) -3-methylbenzoxazoline, 2- (β-naphthoylmethylene) -3-methyl-β-naphthoxazoline, 2- (4-biphenoyl) Methylene) -3-methyl-β-naphthoxazoline, 2- (p-fluorobenzoylmethylene) -3-methyl-β- Ftoxazoline), benzothiazole, nitroaniline (m- or p-nitroaniline, 2,4,6-trinitroaniline) or nitroacenaphthene (5-nitroacenaphthene), (2-[(m-hydroxy-p -Methoxy) styryl] benzothiazole, benzoin alkyl ether, N-alkylated phthalone, acetophenone ketal (2,2-dimethoxyphenylethanone), naphthalene, anthracene (2-naphthalenemethanol, 2-naphthalenecarboxylic acid, 9-anthracenemethanol And 9-anthracenecarboxylic acid), benzopyran, azoindolizine, melocoumarin and the like.
Aromatic 2-hydroxyketone (benzophenone), coumarin, ketocoumarin, carbonyl biscoumarin, acetophenone, anthraquinone, xanthone, thioxanthone, and acetophenone ketal are preferred.

  Moreover, in the photo-alignment phase difference agent of the present invention, instead of blending this photosensitizer as a component different from the polymer (1), when obtaining the polymer (1), “other structural unit” The photosensitizing ability can also be imparted to the photoalignable phase difference agent by using a photosensitizer having a polymerizable group as a monomer capable of forming the photo-sensitive agent. In this embodiment, as the polymer (1), a structural unit derived from a photosensitizer having a polymerizable group, that is, an ethylenically unsaturated double bond contained in the photosensitizer having a polymerizable group, etc. A polymer further including a structural unit formed by opening a π bond constituting the polymerization reactive multiple bond is used. In the present invention, as the “photosensitizer having a polymerizable group”, a photosensitizer having a polymerizable group introduced into the original photosensitizer is used to constitute a “photosensitizer having a polymerizable group”. Examples of the polymerizable group include acryloyl, methacryloyl, vinyl, maleimide, itaconyl and derivatives thereof.

  Specific examples of the photosensitizer having a polymerizable group are shown below, but the present invention is not limited to these specific examples.

これらの化合物において、Ｒ³は独立して水素またはメチルであり；ｒは独立して１〜１２の整数である。

In these compounds, R ³ is independently hydrogen or methyl; r is independently an integer of 1-12.

  In addition, when the compounds (S-1) to (S-6) are introduced into the polymer (1), the compounds (S-1) to (S-6) are represented by structural units (S-1 ′) to ( S-6 ′).

ここで、構成単位（Ｓ−１'）〜（Ｓ−６'）において、Ｒ³およびｒは例示化合物（Ｓ−１）〜（Ｓ−６）に記載のＲ³およびｒとそれぞれ同じである。

Here, in the structural unit (S-1 ') ~ ( S-6'), R 3 and r are each the same as R ³ and r according to exemplified compound (S-1) ~ (S -6) .

  In the present invention, the structural unit derived from the “photosensitizer having a polymerizable group” in the polymer (1) is represented by the structural unit represented by the formula (1a) and the formula (1b). The total number of moles of the constituent units can be 10 to 1 mole, preferably 5 to 1 mole, with 100 as the total number of moles.

  As an additive, a coupling agent can be used to improve adhesion to the substrate. As the coupling agent, silane, aluminum and titanate compounds are used. Specifically, silane systems such as 3-glycidoxypropyldimethylethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, and aluminum systems such as acetoalkoxyaluminum diisopropylate And titanate compounds such as tetraisopropyl bis (dioctyl phosphite) titanate.

As an additive, a surfactant can be used in order to improve wettability to the base substrate, leveling property, and coating property. As the surfactant, a silicone-based surfactant, an acrylic-based surfactant, a fluorine-based surfactant, or the like is used. Specifically, BYK (registered trademark) -300, 306, 335, 310, 341, 344, 370, and other silicone surfactants manufactured by BYK Chemie, Big Chemie ( Acrylic surfactants such as Byk (registered trademark) -354, 358, and 361 manufactured by Co., Ltd., SC-101 manufactured by Asahi Glass Co., Ltd., EF-351 manufactured by Tochem Products Co., Ltd., and 352 And fluorinated surfactants.
The photo-alignment phase difference agent of the present invention may contain a liquid crystalline low molecular compound. Of the liquid crystalline low molecular weight compounds, compounds having a polymerizable group are preferred.

[Phase difference film, etc.]
Although the use of the photo-alignment phase difference agent of the present invention described above is not particularly limited, it can be suitably used as a phase difference film. That is, the photo-alignment phase difference agent of the present invention is suitably used as a constituent material for a phase difference film. In the present invention, the retardation film imparts optical anisotropy by irradiating the coating film formed from the above-described photoalignable retardation agent of the present invention with light containing linearly polarized light, and further heating it. Can be obtained.

Here, the photo-alignment phase difference agent of the present invention is typically used as a coating solution in which the polymer (1) is dissolved in an organic solvent.
As the organic solvent used at this time, the solvent used at the time of polymerizing the polymer (1) may be used as it is, or the solvent at the time of polymerization may be temporarily removed and a new solvent may be used again. As the organic solvent newly used at this time, aromatic compounds such as benzene, toluene, xylene, and ethylbenzene; aliphatic compounds such as pentane, hexane, heptane, octane, cyclohexane, and cycloheptane; methanol, ethanol, 1- Alcohols such as propanol, 2-propanol, and ethylene glycol; ethers such as dibutyl ether, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, and dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate , Esters such as butyl acetate, amyl acetate and γ-butyrolactone; From the viewpoint of toxicity and environmental load, 1-propanol, 2-propanol, 1-methoxy-2-propanol, ethylene glycol, diethylene glycol, 2-butoxyethenol, 3-methoxy-3-methylbutanol, ethylene glycol monomethyl ether, Ethylene glycol dimethyl ether, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate or butyl acetate are preferred. From the viewpoint of solvent resistance to the plastic substrate, 1-methoxy-2-propanol, methyl isobutyl ketone, cyclohexanone, cyclopentanone, and the like are preferable. These organic solvents can be used alone or in combination of two or more.

  In the present invention, the retardation film is obtained by using such a photo-alignment retardation agent by a known method (for example, spin coating, gravure coater, reverse gravure, Mayer bar coater, die coater, reverse roll coater, phantom reverse). After applying to the substrate with a roll coater, kiss roll coater, bar coater, knife coater, lip coater, resist coater method) and removing the organic solvent, the resulting coating film is subjected to orientation treatment by polarized light irradiation and heat treatment. Can do.

At this time, the polarized light irradiation to the coating film is performed for aligning the photo-alignment phase difference agent of the present invention, and is performed by irradiating the film with light from a single direction. An alignment axis is formed in the photoalignable phase difference agent by light irradiation. In this case, X-rays, electron beams, ultraviolet rays, visible rays or infrared rays (heat rays) are used as the irradiation light, and it is particularly preferable to use ultraviolet rays. The wavelength of the ultraviolet light is preferably 400 nm or less, and more preferably 180 to 360 nm. As the light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a high-pressure discharge lamp, or a short arc discharge lamp is preferably used. In general, linearly polarized light is irradiated, but there are cases where an alignment function can be imparted by non-polarized light irradiation. However, it is particularly preferable to use linearly polarized light so that the alignment function can be more reliably imparted. Irradiation dose is preferably ^{10mJ / cm 2 ~20000mJ / cm 2} , and most preferably ^{20mJ / cm 2 ~5000mJ / cm 2} . Here, as the photo-alignment phase difference agent of the present invention, when the polymer (1) has both a structural unit represented by the formula (1a) and a structural unit represented by the formula (1b), There is a tendency that this light irradiation can be performed with a low dose.

In addition, the heat treatment for the coating film that has been irradiated with polarized light is performed in order to further uniformly align the photo-alignable phase difference agent having an alignment axis formed by polarized light irradiation. can get. At this time, the heating temperature T is set such that the lower limit and the upper limit of the temperature at which the polymer has a liquid crystal phase are Tm and Ti, respectively.
Tm-50 ° C. ≦ T ≦ Ti
It is preferable that Generally, it is about 60 to 250 ° C, and preferably about 80 to 150 ° C. Tm and Ti correspond to the crystal phase-liquid crystal phase transition temperature and the liquid crystal phase-isotropic phase transition temperature of the polymer, respectively.

  When the linearly polarized light is irradiated in the normal direction to the substrate coated with the photo-alignment phase difference agent of the present invention, isomerization of the photosensitive group arranged along the electric field vibration direction of the linearly polarized light and / or 2 Quantification occurs selectively. Thereafter, the film is oriented in the polarization direction of linearly polarized light or in a direction perpendicular to the polarized light by heat treatment.

  In order to fix the induced orientation, light may be irradiated again after the heat treatment. The light for fixing the alignment preferably has an ultraviolet wavelength of 400 nm or less, and may be linearly polarized light or non-polarized light.

  The retardation film of the present invention is obtained by applying a photo-alignment retardation agent containing a polymer (1) used as a photosensitive liquid crystal polymer and other various compounds added as necessary onto a transparent substrate, It is obtained by aligning the photosensitive liquid crystal polymer by irradiation and heating. The retardation film of the present invention exhibits optical anisotropy expressed by photo-alignment of a photosensitive liquid crystal polymer.

Here, in this invention, it is preferable that the film thickness of a phase difference film shall be 0.5 micrometer-10 micrometers.
Furthermore, an optical film can be obtained using the retardation film of the present invention. Here, the optical film of the present invention means an optical compensation film for realizing an improvement in contrast of a retardation film or a liquid crystal display element and an expansion of a viewing angle range. Such an optical film is specifically a film composed of the retardation film of the present invention, and the retardation film of the present invention itself may be used as an optical film as it is or It may be an optical film formed by combining another film with the retardation film.

  The optical film of the present invention is useful as display elements such as various optical members and liquid crystal display elements and other optical elements.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not restrict | limited by these Examples. The structure of the compound was confirmed by nuclear magnetic resonance spectrum (NMR), infrared absorption spectrum, and mass spectrum. The unit of the phase transition temperature is ° C., C represents a crystal, G represents a glass state, S represents a smectic phase, N represents a nematic phase, and I represents an isotropic liquid phase. The measurement method of physical property values is shown below.

<Weight average molecular weight (Mw) and polydispersity (Mw / Mn)>
Shimadzu LC-9A type gel permeation chromatograph (GPC) manufactured by Shimadzu Corporation and column Shodex (registered trademark) GF-7M HQ (developing solvent: DMF or THF, standard material: polystyrene having a known molecular weight) manufactured by Showa Denko It was.

<Copolymerization ratio>
The reaction conversion rate in the polymerization reaction was detected from the amount of unreacted monomer by gas chromatography (GC) or liquid chromatography, and the copolymerization ratio was calculated using the reaction conversion rate and / or NMR.

<Orientation of retardation film>
It confirmed by the method shown below.
(1) Visual observation method A substrate on which a retardation film was formed was sandwiched and observed between two polarizing plates arranged in crossed Nicols, and the substrate was rotated in a horizontal plane to confirm the light and dark state. The substrate on which the retardation film was formed was observed with a polarizing microscope, and the presence or absence of alignment defects was confirmed.

(2) Measurement with ellipsometer Using an OPTIPRO (registered trademark) ellipsometer manufactured by Shintech Co., Ltd., a substrate having a retardation film was irradiated with light having a wavelength of 550 nm. Retardation was measured while decreasing the incident angle of this light from 90 ° with respect to the film surface. Retardation (phase lag) is represented by Δn × d. The symbol Δn is the optical anisotropy value, and the symbol d is the thickness of the polymer film. Here, the optical anisotropy value represented by Δn is a value called birefringence or refractive index anisotropy.

<Film thickness measurement>
The layer of the retardation film was cut out from the substrate, and the step was measured using a fine shape measuring device (Alphastep IQ, manufactured by KLA TENCOR Co., Ltd.).

<Evaluation of optical anisotropy value (Δn)>
From the retardation and film thickness value obtained for the retardation film layer, Δn = retardation / film thickness was calculated.

[Example 1]
(I) Synthesis of compound (M-2)

化合物（Ｍ−２）は、特開２００９−１９１１１７号公報に記載の方法に従い合成した。

Compound (M-2) was synthesized according to the method described in JP-A-2009-191117.

(Ii) Synthesis of Compound (M-1) Compound (M-1) was synthesized according to the following scheme.

以下、化合物（Ｍ−１）の合成について、より具体的に説明する。

Hereinafter, the synthesis of the compound (M-1) will be described more specifically.

(First Step: Synthesis of Compound (ex-1))
400 g of trans-p-coumaric acid was added to 1200 ml of methanol, 10 g of concentrated sulfuric acid was added dropwise, and the mixture was stirred for 5 hours with heating under reflux. After cooling to room temperature, methanol was distilled off under reduced pressure. The obtained residue was poured into 2000 ml of ice water, 2000 ml of ethyl acetate was added, and the organic layer was separated. The obtained organic layer was washed with saturated aqueous sodium hydrogen carbonate and water, and dried over anhydrous magnesium sulfate. Ethyl acetate was distilled off under reduced pressure, and the resulting residue was recrystallized from ethanol to obtain 280 g of compound (ex-1).

(Second stage: Synthesis of compound (M-1))
5.8 g of compound (ex-1), 10.0 g of compound (M-2) and 0.8 g of 4-dimethylaminopyridine (DMAP) were added to 100 ml of dichloromethane, and the mixture was stirred while cooling under a nitrogen atmosphere. Thereto was added dropwise 20 ml of a dichloromethane solution of 7.1 g of 1,3-dicyclohexylcarbodiimide (DCC). After dropping, the mixture was stirred at room temperature for 16 hours. The deposited precipitate was separated by filtration, and the organic layer was washed with water and dried over anhydrous magnesium sulfate. Dichloromethane was distilled off under reduced pressure, and the residue was purified by column chromatography (silica gel, eluent: toluene-ethyl acetate mixture (volume ratio: toluene / ethyl acetate = 8/1)) and recrystallized from ethanol. Compound (M-1) 9.8g was obtained.

The phase transition temperature and NMR analysis value of the obtained compound (M-1) are as follows.
Phase transition temperature: C 67 SmA 96 N 104 I
¹ H-NMR (CDCl ₃ ; δ ppm): 8.13 (d, 2H), 7.70 (d, 1H), 7.58 (d, 2H), 7.24 (d, 2H), 6.97 (D, 2H), 6.43 (d, 1H), 6.10 (s, 1H), 5.56 (s, 1H), 4.17 (t, 2H), 4.05 (t, 2H) , 3.81 (s, 3H), 1.95 (s, 3H), 1.89-1.82 (m, 2H), 1.78-1.71 (m, 2H), 1.58-1 .45 (m, 4H).

(Iii) Synthesis of polymer (P-1) Polymer (P-1) was synthesized from compound (M-1) and compound (M-2) by the following procedure.

2.0 g of the compound (M-1), 2.0 g of the compound (M-2) and 0.15 g of azobisisobutyronitrile (AIBN) were added to 20 ml of THF, and the mixture was stirred for 10 hours with heating under reflux in a nitrogen atmosphere. The reaction solution was poured into toluene and reprecipitated. Crystals were separated by filtration and dried to obtain 3.5 g of polymer (P-1). The copolymerization ratios are M-1 = 0.4 and M-2 = 0.6 in terms of mole fraction.
The obtained polymer (P-1) has Mw of 34000 and Mw / Mn of 2.3, and has a liquid crystal phase in the range of 136 ° C to 162 ° C.

(Iv) Preparation of photo-alignment phase difference agent (H-1) The polymer (P-1) was dissolved in cyclopentanone (CPN) to obtain a solution having a solid content concentration of 20% by weight. The solution was filtered with a filter having a pore size of 0.2 μm to prepare a photo-alignment phase difference agent (H-1).

[Example 2]
<Preparation of retardation film F-1>
The photo-alignment phase difference agent (H-1) was applied onto a glass substrate by spin coating. At this time, the coating property was good. The substrate was heated at 80 ° C. for 2 minutes to remove the solvent, thereby forming a coating film. Photo-alignment treatment was performed by irradiating 100 mJ / cm ² of linearly polarized ultraviolet light having a wavelength of about 313 nm from the direction of 90 ° with respect to the coated surface from an ultrahigh pressure mercury lamp (USHIO INC.). The substrate was heated at 130 ° C. for 5 minutes to obtain a retardation film (F-1).

When the retardation film (F-1) was sandwiched between two polarizing plates made of crossed Nicols and rotated in a horizontal plane, the film became bright and dark, and was confirmed to have horizontal alignment (homogeneous alignment).
When this retardation film was observed with a polarizing microscope, it was confirmed that there was no alignment defect and the film had a uniform alignment. When the retardation was measured, it was 120 nm.
When the film thickness of this retardation film was measured, it was 2.3 μm and Δn was 0.05.

[Example 3]
(I) Synthesis of polymer (P-2) Polymer (P-2) was synthesized from compound (M-1) by the following procedure.
4.0 g of compound (M-1) and 0.15 g of azobisisobutyronitrile (AIBN) were added to 20 ml of THF, and the mixture was stirred for 10 hours under reflux with heating under a nitrogen atmosphere. The reaction solution was poured into toluene and reprecipitated. Crystals were separated by filtration and dried to obtain 3.2 g of polymer (P-2).
The obtained polymer (P-2) has Mw of 35000 and Mw / Mn of 2.5, and has a liquid crystal phase in the range of 97 ° C to 205 ° C.

(Ii) Preparation of photo-alignment phase difference agent (H-2) 0.5% by weight of polymer (P-2) and Byk-361 with respect to the polymer was dissolved in cyclopentanone (CPN), and the solid content concentration The solution was 20% by weight. The solution was filtered with a filter having a pore size of 0.2 μm to prepare a photo-alignment phase difference agent (H-2).

[Example 4]
<Preparation of retardation film F-2>
A photo-alignment phase difference agent (H-2) was applied onto a glass substrate by spin coating. At this time, the coating property was good. The substrate was heated at 80 ° C. for 2 minutes to remove the solvent, thereby forming a coating film. A photo-alignment treatment was performed by irradiating the coating surface with 1000 mJ / cm ² of linearly polarized ultraviolet light having a wavelength of about 313 nm from the direction of 90 ° with respect to the coating surface from an ultrahigh pressure mercury lamp (USHIO INC.). The substrate was heated at 150 ° C. for 5 minutes to obtain a retardation film (F-2).

When the retardation film (F-2) was sandwiched between two polarizing plates made of crossed Nicols and rotated in a horizontal plane, the film became bright and dark, and was confirmed to have horizontal alignment (homogeneous alignment).
When this retardation film was observed with a polarizing microscope, it was confirmed that there was no alignment defect and the film had a uniform alignment. When the retardation was measured, it was 115 nm.

[Example 5]
(I) Synthesis of Compound (M-3) Compound (M-3) was synthesized according to the following scheme.

以下、化合物（Ｍ−３）の合成について、より具体的に説明する。

Hereinafter, the synthesis of the compound (M-3) will be described more specifically.

(First stage: Synthesis of compound (ex-2))
9.9 g of the compound (ex-1), 10.0 g of acetoxybenzoic acid and 1.4 g of 4-dimethylaminopyridine (DMAP) were added to 100 ml of dichloromethane, followed by stirring while cooling under a nitrogen atmosphere. Thereto, 24 ml of a dichloromethane solution of 12.1 g of 1,3-dicyclohexylcarbodiimide (DCC) was dropped. After dropping, the mixture was stirred at room temperature for 16 hours. The deposited precipitate was separated by filtration, and the organic layer was washed with water and dried over anhydrous magnesium sulfate. Dichloromethane was distilled off under reduced pressure, and the residue was purified by column chromatography (silica gel, eluent: toluene-ethyl acetate mixture (volume ratio: toluene / ethyl acetate = 8/1)) and recrystallized from toluene. Next, the obtained crystals were added to a mixed solvent of 100 ml of THF and 50 ml of methanol, and stirred while cooling under a nitrogen atmosphere. Thereto, 10 ml of 28% aqueous ammonia solution was added dropwise, and after the addition, the mixture was stirred at room temperature for 8 hours. Ethyl acetate was added for extraction, and the organic layer was washed with water and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and recrystallization with ethanol gave 11.1 g of compound (ex-2).

(Second stage: Synthesis of compound (M-3))
9.7 g of the compound (ex-2), 10.0 g of the compound (M-2) and 0.8 g of 4-dimethylaminopyridine (DMAP) were added to 100 ml of dichloromethane, followed by stirring while cooling under a nitrogen atmosphere. Thereto was added dropwise 20 ml of a dichloromethane solution of 7.1 g of 1,3-dicyclohexylcarbodiimide (DCC). After dropping, the mixture was stirred at room temperature for 16 hours. The deposited precipitate was separated by filtration, and the organic layer was washed with water and dried over anhydrous magnesium sulfate. Dichloromethane was distilled off under reduced pressure, and the residue was purified by column chromatography (silica gel, eluent: toluene-ethyl acetate mixture (volume ratio: toluene / ethyl acetate = 8/1)) and recrystallized from ethanol. Compound (M-3) 10.8 g was obtained.

The phase transition temperature and NMR analysis value of the obtained compound (M-3) are as follows.
Phase transition temperature: C 88 SmA 200 <I
¹ H-NMR (CDCl ₃ ; δ ppm): 8.28 (d, 2H), 8.16 (d, 2H), 7.72 (d, 1H), 7.61 (d, 2H), 7.38 (D, 2H), 7.27 (d, 2H), 6.99 (d, 2H), 6.44 (d, 1H), 6.11 (s, 1H), 5.56 (s, 1H) , 4.18 (t, 2H), 4.06 (t, 2H), 3.82 (s, 3H), 1.95 (s, 3H), 1.89-1.82 (m, 2H), 1.77-1.70 (m, 2H), 1.59-1.45 (m, 4H).

(Ii) Synthesis of polymer (P-3) Polymer (P-3) was synthesized from compound (M-2) and compound (M-3) by the following procedure.
1.0 g of compound (M-2), 3.0 g of compound (M-3) and 0.15 g of azobisisobutyronitrile (AIBN) were added to 20 ml of THF, and the mixture was stirred for 10 hours under reflux with heating in a nitrogen atmosphere. The reaction solution was poured into toluene and reprecipitated. Crystals were separated by filtration and dried to obtain 2.9 g of polymer (P-3). The copolymerization ratios are M-2 = 0.35 and M-3 = 0.65 in terms of mole fraction.
The obtained polymer (P-3) has Mw of 37000 and Mw / Mn of 2.5, and has a liquid crystal phase in the range of 148 ° C to 195 ° C.

(Iii) Preparation of photo-alignment phase difference agent (H-3) The polymer (P-3) was dissolved in cyclopentanone (CPN) to obtain a solution having a solid concentration of 10% by weight. The solution was filtered with a filter having a pore diameter of 0.2 μm to prepare a photoalignable phase difference agent (H-3).

[Example 6]
<Preparation of retardation film F-3>
The photo-alignment phase difference agent (H-3) was applied onto a glass substrate by spin coating. At this time, the coating property was good. The substrate was heated at 80 ° C. for 2 minutes to remove the solvent, thereby forming a coating film. Photo-alignment treatment was performed by irradiating 100 mJ / cm ² of linearly polarized ultraviolet light having a wavelength of about 313 nm from the direction of 90 ° with respect to the coated surface from an ultrahigh pressure mercury lamp (USHIO INC.). The substrate was heated at 150 ° C. for 5 minutes to obtain a retardation film (F-3).

When the phase difference film (F-3) was sandwiched between two polarizing plates made of crossed Nicols and rotated in a horizontal plane, the film became bright and dark, and was confirmed to have horizontal alignment (homogeneous alignment).
When this retardation film was observed with a polarizing microscope, it was confirmed that there was no alignment defect and the film had a uniform alignment. When the retardation was measured, it was 85 nm.

[Example 7]
(I) Synthesis of Compound (M-4) Compound (M-4) was synthesized according to the following scheme.

以下、化合物（Ｍ−４）の合成について、より具体的に説明する。

Hereinafter, the synthesis of the compound (M-4) will be described more specifically.

(First stage: synthesis of compound (ex-3))
20.0 g of acetoxybenzoic acid and 28.0 g of 3,4-dihydropyran were added to 200 ml of dichloromethane and stirred while cooling under a nitrogen atmosphere. Thereto, 0.2 g of p-toluenesulfonic acid (PTSA) was added. After dropping, the mixture was stirred for 8 hours while cooling. Saturated multistory water was added for extraction, and the organic layer was washed with water and dried over anhydrous magnesium sulfate. Dichloromethane was distilled off under reduced pressure. Next, the obtained residue was added to 100 ml of methanol and stirred while cooling under a nitrogen atmosphere. Thereto, 16 ml of 28% aqueous ammonia solution was added dropwise, and the mixture was stirred at room temperature for 8 hours. Methanol was distilled off under reduced pressure, ethyl acetate and water were added for extraction, and the organic layer was washed with water and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and recrystallization with heptane gave 18.0 g of compound (ex-3).

(Second stage: Synthesis of compound (M-4))
7.3 g of the compound (ex-3), 10.0 g of the compound (M-2) and 0.8 g of 4-dimethylaminopyridine (DMAP) were added to 100 ml of dichloromethane and stirred while cooling under a nitrogen atmosphere. Thereto was added dropwise 20 ml of a dichloromethane solution of 7.1 g of 1,3-dicyclohexylcarbodiimide (DCC). After dropping, the mixture was stirred at room temperature for 16 hours. The deposited precipitate was separated by filtration, and the organic layer was washed with water and dried over anhydrous magnesium sulfate. Dichloromethane was distilled off under reduced pressure, and the residue was added to 100 ml of THF, followed by stirring while cooling under a nitrogen atmosphere. Thereto, 50 ml of a 6N hydrochloric acid aqueous solution was dropped, and after the dropping, the mixture was stirred at room temperature for 4 hours. Ethyl acetate was added for extraction, and the organic layer was washed with water and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, the residue was purified by column chromatography (silica gel, eluent: toluene-ethyl acetate mixture (volume ratio: toluene / ethyl acetate = 2/1)), and recrystallized with ethanol to give a compound. (M-4) 6.5g was obtained.

The phase transition temperature and NMR analysis value of the obtained compound (M-4) are as follows.
Phase transition temperature: C 115 SmA 200 <I
¹ H-NMR (CDCl ₃ ; δ ppm): 13.07 (s, 1H), 8.09 (d, 2H), 8.04 (d, 2H), 7.41 (d, 2H), 7.12 (D, 2H), 6.02 (s, 1H), 5.67 (s, 1H), 4.14-4.07 (m, 4H), 1.88 (s, 3H), 1.82- 1.73 (m, 2H), 1.69-1.62 (m, 2H), 1.53-1.38 (m, 4H).

(Ii) Synthesis of polymer (P-4) Polymer (P-4) was synthesized from compound (M-1) and compound (M-4) by the following procedure.
2.0 g of the compound (M-1), 2.0 g of the compound (M-4) and 0.15 g of azobisisobutyronitrile (AIBN) were added to 20 ml of THF, and the mixture was stirred for 10 hours with heating under reflux in a nitrogen atmosphere. The reaction solution was poured into toluene and reprecipitated. Crystals were separated by filtration and dried to obtain 3.1 g of polymer (P-4). The copolymerization ratios are M-1 = 0.5 and M-4 = 0.5 in terms of mole fraction.
The obtained polymer (P-4) has Mw of 33000 and Mw / Mn of 2.3, and has a liquid crystal phase in the range of 125 ° C to 205 ° C.

(Iii) Preparation of photo-alignment phase difference agent (H-4) The polymer (P-4) was dissolved in cyclopentanone (CPN) to obtain a solution having a solid concentration of 10% by weight. The solution was filtered with a filter having a pore size of 0.2 μm to prepare a photoalignable phase difference agent (H-4).

[Example 8]
<Preparation of retardation film F-4>
A photo-alignment phase difference agent (H-4) was applied onto a glass substrate by spin coating. At this time, the coating property was good. The substrate was heated at 80 ° C. for 2 minutes to remove the solvent, thereby forming a coating film. Photo-alignment treatment was performed by irradiating 40 mJ / cm ² of linearly polarized ultraviolet light having a wavelength in the vicinity of 313 nm from the direction of 90 ° with respect to the coated surface from an ultrahigh pressure mercury lamp (USHIO INC.). The substrate was heated at 150 ° C. for 5 minutes to obtain a retardation film (F-4).

When the retardation film (F-4) was sandwiched between two polarizing plates made of crossed Nicols and rotated in a horizontal plane, the film became bright and dark, and was confirmed to have horizontal alignment (homogeneous alignment).
When this retardation film was observed with a polarizing microscope, it was confirmed that there was no alignment defect and the film had a uniform alignment. When the retardation was measured, it was 98 nm.

[Comparative Example 1]
(I) Synthesis of compound (M-5)

化合物（Ｍ−５）は、特開２００４−１７０５９５号公報に記載の方法に従い合成した。

Compound (M-5) was synthesized according to the method described in JP-A No. 2004-170595.

(Ii) Synthesis of polymer (P-5) Polymer (P-5) was synthesized from compound (M-5) by the following procedure.
4.0 g of compound (M-5) and 0.15 g of azobisisobutyronitrile (AIBN) were added to 20 ml of THF, and the mixture was stirred under heating and reflux for 10 hours under a nitrogen atmosphere. The reaction solution was poured into toluene and reprecipitated. The crystal was separated by filtration and dried to obtain 3.6 g of polymer (P-5).
The obtained polymer (P-5) has Mw of 33000 and Mw / Mn of 2.7, and has a liquid crystal phase in the range of 119 ° C to 280 ° C or higher.

[Comparative Example 2]
(I) Synthesis of polymer (P-6) According to the following procedure, 2.0 g of compound (M-2), 2.0 g of compound (M-5) and 0.15 g of azobisisobutyronitrile (AIBN) were added to 20 ml of THF. In addition, the mixture was stirred with heating under reflux in a nitrogen atmosphere for 10 hours. The reaction solution was poured into toluene and reprecipitated. The crystals were separated by filtration and dried to obtain 2.8 g of polymer (P-6). The copolymerization ratios are M-2 = 0.6 and M-5 = 0.4 in terms of mole fraction.
The obtained polymer (P-6) has Mw of 35000 and Mw / Mn of 2.2, and has a liquid crystal phase in the range of 110 ° C to 188 ° C.

<Polymer solubility>
For each of the polymers (P-1) to (P-6), the total weight of the polymer and the solvent is 100 parts by weight, and the solubility in various solvents when the polymer is 5, 10, 20 parts by weight is visually evaluated. And what melt | dissolved completely was set as (circle), and the thing with an insoluble matter was set as x. The results are shown in Table 2 below.

  The photo-alignment phase difference agent of the present invention is made of a photosensitive liquid crystal polymer and is a phase difference agent suitable for the photo-alignment method. Further, since the photo-alignment phase difference agent of the present invention has good solubility in a solvent having low toxicity and environmental load, a retardation film is provided without using a solvent having high toxicity and environmental load. be able to.

  Moreover, since the retardation film obtained using the photo-alignment phase difference agent of the present invention does not require an alignment film, simplification of the manufacturing process and reduction of member costs are expected. In addition, special orientation such as three-dimensional orientation is possible, and lamination of retardation films becomes easy. The retardation film of the present invention is suitable for use in optical films and liquid crystal display device applications.

Claims (7)

The structural unit represented by the formula (1a) and the structural unit represented by the formula (1b) at a molar ratio m: n;
The photo-alignment phase difference agent comprising a polymer (1) in which m and n satisfy a relationship of 0.1 ≦ m ≦ 1, 0 ≦ n ≦ 0.9, m + n = 1:

In formula (1a), R ¹ is hydrogen or methyl; R ^{1 ′} is alkyl having 1 to 10 carbons; A ¹ is each independently 1,4-phenylene, pyridine-2,5-diyl, Any divalent group selected from naphthalene-2,6-diyl and biphenyl-4,4′-diyl, in which any hydrogen is fluorine, chlorine, cyano, hydroxy, formyl, acetoxy, Acetyl, trifluoroacetyl, difluoromethyl, trifluoromethyl, alkyl having 1 to 5 carbons or alkoxy having 1 to 5 carbons may be substituted; each Z ¹ independently represents a single bond, —COO—, — CH═CH—COO—, —CH ₂ CH ₂ —COO—, —CH ₂ O—, —CF ₂ O—, —CONH—, —NHCO—, — (CH ₂ ) ₄ — or —CH ₂ CH ₂ — And A is an integer of 1 to 3; W ¹ and W ^{1 ′} are each independently hydrogen, fluorine, chlorine, trifluoromethyl, alkyl having 1 to 5 carbons or alkoxy having 1 to 5 carbons; p is an integer from 1 to 12;

In formula (1b), R ² is hydrogen or methyl; A ² is each independently 1,4-phenylene, pyridine-2,5-diyl, naphthalene-2,6-diyl and biphenyl-4,4 ′. -Any divalent group selected from diyl, in which any hydrogen is fluorine, chlorine, cyano, hydroxy, formyl, acetoxy, acetyl, trifluoroacetyl, difluoromethyl, trifluoromethyl, carbon May be substituted with alkyl of 1 to 5 or alkoxy of 1 to 5 carbons; each Z ² is independently a single bond, —COO—, —CH═CH—COO—, —CH ₂ CH ₂ —COO. _{-, - CH 2 O -,} - CF 2 O -, - CONH -, - NHCO -, - (CH 2) 4 - or -CH ₂ CH ₂ - a and; b is an integer from 0 to 2; q 1-12 Is an integer. In the structural unit represented by the formula (1a), R ^{1 ′} is alkyl having 1 to 5 carbon atoms; A ¹ is each independently 1,4-phenylene, naphthalene-2,6-diyl and biphenyl- Any divalent group selected from 4,4′-diyl, in which any hydrogen is fluorine, trifluoromethyl, alkyl having 1 to 3 carbons or alkoxy having 1 to 3 carbons; Z ¹ is independently —COO— or —CH ₂ CH ₂ —COO—; a is 1 or 2; W ¹ and W ^{1 ′} are each independently hydrogen, fluorine , Alkyl having 1 to 3 carbons or alkoxy having 1 to 3 carbons;
In the structural unit represented by the formula (1b), each A ² is independently any one divalent selected from 1,4-phenylene, naphthalene-2,6-diyl and biphenyl-4,4′-diyl. In the divalent group, any hydrogen may be replaced by fluorine, trifluoromethyl, alkyl having 1 to 3 carbons or alkoxy having 1 to 3 carbons; each Z ² is independently- COO- or -CH ₂ CH ₂ -COO- a and; b is characterized in that it is a 0 or a 1, photoalignable retardation agent according to claim 1.   3. The photo-alignment phase difference agent according to claim 1, wherein m and n satisfy a relationship of 0.35 <m ≦ 1, 0 ≦ n <0.65, and m + n = 1.   The photoalignable phase difference agent according to any one of claims 1 to 3, wherein the polymer (1) has a weight average molecular weight of 1,000 to 500,000.   A coating film formed from the photoalignable phase difference agent according to any one of claims 1 to 4 is irradiated with light containing linearly polarized light, and further heated to impart optical anisotropy. The retardation film obtained by this.   An optical film produced using the retardation film according to claim 5.   The display element manufactured using the optical film of Claim 6.