JP2019172867A - Copolymer and optical film using the same - Google Patents

Abstract

To provide a novel copolymer that is expected to be an optical film excellent in retardation characteristics such as having a high retardation even in a thin film state, and an optical film using the copolymer.SOLUTION: The copolymer comprises: a unit A having a benzene ring residue unit and a polar group (a cyano group, an ester group, an amide group or an acyl group) residue unit; a unit B having an m-membered heterocyclic residue containing at least one hetero atom or a five-membered ring residue or a six-membered ring residue containing no hetero atoms; and an alkyl (meth)acrylate unit C having a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms.SELECTED DRAWING: None

Description

  The present invention relates to a novel copolymer and an optical film using the same, and more specifically, an optical film having a high retardation even in a thin film, particularly an optical compensation film for a liquid crystal display element or an organic EL use. The present invention relates to a novel copolymer suitable for a retardation film for a circularly polarizing plate.

  Liquid crystal displays are widely used as smartphones, computer monitors, laptop computers, and televisions as the most important display devices in the multimedia society.

  Many optical films are used for improving the display characteristics of the liquid crystal display. In particular, the retardation film plays a major role in improving contrast and compensating for color tone when viewed from the front or obliquely. As the conventional retardation film, polycarbonate or cyclic polyolefin is used, and these polymers are polymers having positive birefringence. Here, the sign of birefringence is defined as shown below.

  The optical anisotropy of the polymer film molecularly oriented by stretching or the like is such that the refractive index in the fast axis direction in the film plane when the film is stretched is nx, the refractive index in the in-plane direction perpendicular to the film is ny, and the film It can be represented by a refractive index ellipsoid where the refractive index in the thickness direction is nz.

  That is, in the uniaxial stretching of the polymer having negative birefringence, the refractive index in the stretching axis direction is small (fast axis: stretching direction), and in the uniaxial stretching of the polymer having positive birefringence, the axial direction perpendicular to the stretching axis. Has a small refractive index (fast axis: direction perpendicular to the stretching direction).

  Many polymers have positive birefringence. As a polymer having negative birefringence, there are acrylic resin and polystyrene. However, acrylic resin has a small retardation, and the properties as a retardation film are not sufficient. Since polystyrene has a large photoelastic coefficient in the low-temperature region, it has a problem of stability of phase difference such as phase difference being changed by a slight stress, and a practical problem of low heat resistance, and is not used at present. .

  A stretched polymer film exhibiting negative birefringence has a high refractive index in the thickness direction of the film and becomes an unprecedented retardation film. For example, a super twist nematic liquid crystal display (STN-LCD) or a vertical alignment liquid crystal display (VA-LCD), in-plane oriented liquid crystal display (IPS-LCD), reflective liquid crystal display (reflective LCD), etc., useful as a retardation film for compensating viewing angle characteristics and a viewing angle compensation film for a deflection plate There is a strong market demand for retardation films having negative birefringence.

  A method for producing a film has been proposed in which a polymer having positive birefringence is used to increase the refractive index in the thickness direction of the film. One is a treatment method (for example, Patent Documents 1 to 3) in which a heat-shrinkable film is bonded to one side or both sides of a polymer film, and the laminate is subjected to a heat stretching treatment to apply a shrinkage force in the film thickness direction of the polymer film. Reference). In addition, a method of uniaxial stretching in a plane while applying an electric field to a polymer film has been proposed (see, for example, Patent Document 4).

  In addition, a retardation film composed of fine particles having negative optical anisotropy and a transparent polymer has been proposed (for example, see Patent Document 5).

  However, the methods proposed in Patent Documents 1 to 4 have a problem that productivity is inferior because the manufacturing process becomes very complicated. Also, the control of the uniformity of the phase difference and the like is extremely difficult as compared with the conventional control by stretching.

  The retardation film obtained in Patent Document 5 is a retardation film that exhibits negative birefringence by adding fine particles having negative optical anisotropy. From the viewpoint of simplification of production method and economical efficiency, fine particles are obtained. There is a need for retardation films that do not require the addition of.

  Moreover, the fumaric acid diester type | system | group copolymer and the film consisting thereof are proposed (for example, refer patent documents 6-12).

  Although the fumaric acid diester copolymer proposed in Patent Documents 6 to 12 and a film comprising the same have a high retardation, a film having a high retardation even in a thin film is required at present. Yes.

  Furthermore, a single-film optical compensation film material by combining a positive birefringent material and a negative birefringent material has been proposed (see, for example, Patent Documents 13 and 14), and achieves higher performance optical characteristics. Therefore, there is a need for a polymer material exhibiting negative birefringence that can be combined.

Japanese Patent No. 2818983 JP-A-5-297223 JP-A-5-323120 JP-A-6-88909 JP 2005-156862 A JP 2008-112141 A JP 2012-032784 A WO2012 / 005120 JP 2008-129465 A JP 2006-193616 A WO2014 / 013982 WO2014 / 084178 WO2014 / 196552 WO2016 / 060115

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a novel copolymer suitable for an optical film having a high retardation even in a thin film and an optical film comprising the same. There is to do. Another object of the present invention is to provide a copolymer that has excellent optical properties and can be easily combined with a different polymer, and an optical film comprising the same.

  As a result of intensive studies in order to solve the above problems, the present inventors have found that a specific copolymer can solve the above problems, and have completed the present invention.

  That is, the present invention includes a residue unit A represented by the general formula (1), a residue unit B represented by the general formula (2), and a residue unit C represented by the general formula (3). The present invention relates to a copolymer characterized by

(Here, R ₁ and R ₂ are each independently hydrogen (except when R ₁ and R ₂ are both hydrogen), a cyano group, an ester group (—C (═O) OX ₁ ), An amide group (—C (═O) N (X ₂ ) (X ₃ )), or an acyl group (—C (═O) X ₄ ) (where X _{1 to} X ₃ each independently represents 1 carbon atom) 12 linear alkyl group, branched alkyl group having 1 to 12 carbon atoms, or cyclic alkyl group having 3 to 6 carbon atoms, _{X 4} is a linear alkyl group having 1 to 12 carbon atoms, carbon atoms R _{3 to} R ₇ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, carbon, and a branched alkyl group having 1 to 12 carbon atoms or a cyclic group having ₃ to 14 carbon atoms. A branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, halogen, hydroxy group, carboxy group, nitro , A cyano group, an alkoxy group _(-OX 5), an ester group _{(-C (= O) OX 6} ), an amide group _{(-C (= O) N (} X 7) (X 8)), an acyl group (-C (═O) X ₉ ), an amino group (—N (X ₁₀ ) (X ₁₁ )), or a sulfonic acid group (—SOOX ₁₂ ) (where X _{5 to} X ₈ each independently represent 1 carbon atom) Represents a linear alkyl group having ˜12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, and X _{9 to} X ₁₂ are each independently hydrogen, 1 to 12 carbon atoms. A straight-chain alkyl group, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.), Wherein at least one of R _{3 to} R ₇ is a hydroxy group or a carboxy group It is shown. in addition, R ₃ to R ₇ may form a fused ring structure adjacent substituents It may be.)

(Here, R ₈ represents an m-membered heterocyclic residue containing one or more heteroatoms, or a 5-membered or 6-membered ring residue not containing a heteroatom (provided that R ₈ contains a heteroatom) In the case of no 6-membered ring residue, at least one of R _{3 to} R ₇ in the general formula (1) represents a hydroxy group.), M represents an integer of 5 to 10. The m-membered ring heterocyclic residue The group, the 5-membered ring residue, and the 6-membered ring residue may form a condensed ring structure.)

(Here, R ₉ and R ₁₀ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms. Show.)
Hereinafter, the copolymer suitable for the optical film of the present invention will be described in detail.

  The copolymer of the present invention comprises a residue unit A represented by the general formula (1), a residue unit B represented by the general formula (2), and a residue unit C represented by the general formula (3). It is a copolymer characterized by including. The copolymer comprises the residue unit A, the residue unit B, and the residue unit C, and thus exhibits a higher retardation even in a thin film.

(Here, R ₁ and R ₂ are each independently hydrogen (except when R ₁ and R ₂ are both hydrogen), a cyano group, an ester group (—C (═O) OX ₁ ), An amide group (—C (═O) N (X ₂ ) (X ₃ )), or an acyl group (—C (═O) X ₄ ) (where X _{1 to} X ₃ each independently represents 1 carbon atom) 12 linear alkyl group, branched alkyl group having 1 to 12 carbon atoms, or cyclic alkyl group having 3 to 6 carbon atoms, _{X 4} is a linear alkyl group having 1 to 12 carbon atoms, carbon atoms R _{3 to} R ₇ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, carbon, and a branched alkyl group having 1 to 12 carbon atoms or a cyclic group having ₃ to 14 carbon atoms. A branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, halogen, hydroxy group, carboxy group, nitro , A cyano group, an alkoxy group _(-OX 5), an ester group _{(-C (= O) OX 6} ), an amide group _{(-C (= O) N (} X 7) (X 8)), an acyl group (-C (═O) X ₉ ), an amino group (—N (X ₁₀ ) (X ₁₁ )), or a sulfonic acid group (—SOOX ₁₂ ) (where X _{5 to} X ₈ each independently represent 1 carbon atom) Represents a linear alkyl group having ˜12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, and X _{9 to} X ₁₂ are each independently hydrogen, 1 to 12 carbon atoms. A straight-chain alkyl group, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.), Wherein at least one of R _{3 to} R ₇ is a hydroxy group or a carboxy group It is shown. in addition, R ₃ to R ₇ may form a fused ring structure adjacent substituents It may be.)

(Here, R ₈ represents an m-membered heterocyclic residue containing one or more heteroatoms, or a 5-membered or 6-membered ring residue not containing a heteroatom (provided that R ₈ contains a heteroatom) In the case of no 6-membered ring residue, at least one of R _{3 to} R ₇ in the general formula (1) represents a hydroxy group.), M represents an integer of 5 to 10. The m-membered ring heterocyclic residue The group, the 5-membered ring residue, and the 6-membered ring residue may form a condensed ring structure.)

(Here, R ₉ and R ₁₀ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms. Show.)
In the general formula (1) of the present invention, R ₁ and R ₂ are each independently hydrogen (except when R ₁ and R ₂ are both hydrogen), a cyano group, an ester group (—C (═O ) OX ₁ ), an amide group (—C (═O) N (X ₂ ) (X ₃ )), or an acyl group (—C (═O) X ₄ ) (where X _{1 to} X ₃ are each independently And a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, and X ₄ is a linear chain having 1 to 12 carbon atoms. An alkyl group, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms).

Examples of the linear alkyl group having 1 to 12 carbon atoms in X _{1 to} X ₄ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the branched alkyl group having 1 to 12 carbon atoms include isopropyl group, sec-butyl group, tert-butyl group, isobutyl group and the like, and cyclic groups having 3 to 6 carbon atoms in X _{1 to} X ₃ . Examples of the alkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group. Examples of the cyclic group having 3 to 14 carbon atoms in X ₄ include a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, a phenyl group, A naphthyl group etc. are mentioned.

R ₁ in the general formula (1) of the present invention expresses a higher phase difference, and therefore includes a cyano group; a methyl ester group, an ethyl ester group, an n-propyl ester group, an isopropyl ester group, an isobutyl ester group, and the like. Ester group; amide group such as dimethylamide group, diethylamide group, di-n-propylamide group, diisopropylamide group; preferably an acyl group such as acetyl group, propionyl group, benzoyl group, cyano group, methyl ester group, More preferably, they are ethyl ester group, n-propyl ester group, isopropyl ester group, isobutyl ester group, dimethylamide group, diethylamide group, di-n-propylamide group, diisopropylamide group, benzoyl group, cyano group, methyl ester Group, ethyl ester group, n-pro Particularly preferred are a pill ester group, an isopropyl ester group and an isobutyl ester group.

R ₂ in the general formula (1) of the present invention expresses a higher phase difference, so that hydrogen; cyano group; methyl ester group, ethyl ester group, n-propyl ester group, isopropyl ester group, isobutyl ester group It is preferably an ester group such as hydrogen, cyano group, methyl ester group, ethyl ester group, n-propyl ester group, isopropyl ester group, isobutyl ester group, and more preferably a cyano group or isobutyl ester group. It is particularly preferred.

R _{3 to} R ₇ in the general formula (1) of the present invention are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or 3 to 14 carbon atoms. Cyclic alkyl group, halogen, hydroxy group, carboxy group, nitro group, cyano group, alkoxy group (—OX ₅ ), ester group (—C (═O) OX ₆ ), amide group (—C (═O) N ( X ₇ ) (X ₈ )), acyl group (—C (═O) X ₉ ), amino group (—N (X ₁₀ ) (X ₁₁ )), or sulfonyl group (—SOOX ₁₂ ) (where X _{5 to} X ₈ each independently represent a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, and X _{9 to} X 8 ₁₂ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, A branched alkyl group having 1 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms), and at least one of R _{3 to} R ₇ represents a hydroxy group or a carboxy group. R _{3 to} R ₇ may form a condensed ring structure with adjacent substituents.

Examples of the linear alkyl group having 1 to 12 carbon atoms in R _{3 to} R ₇ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the branched alkyl group having 1 to 12 carbon atoms include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group and the like, and examples of the cyclic alkyl group having 3 to 14 carbon atoms include , Cyclopropyl group, cyclobutyl group, cyclohexyl group and the like.

Examples of the halogen in R _{3 to} R ₇ include fluorine, chlorine, bromine and the like.

Examples of the linear alkyl group having 1 to ₁₂ carbon atoms in X _{5 to} X ₁₂ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the branched alkyl group having 1 to 12 carbon atoms include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group and the like, and examples of the cyclic alkyl group having 3 to 6 carbon atoms include , Cyclopropyl group, cyclobutyl group, cyclohexyl group and the like.

In the present invention, when at least one of R _{3 to} R _{7 represents} a hydroxy group or a carboxy group, good compatibility is exhibited, and complexing with a different polymer becomes easy.

As R < ₃ > -R < ₇ > in General formula (1) of this invention, since a higher phase difference is expressed, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group Tert-butyl group, isobutyl group, cyclohexyl group, fluorine atom, chlorine atom, bromine atom, hydroxy group, carboxy group, formyl group, cyano group, nitro group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group , Methyl ester group, ethyl ester group, n-propyl ester group, isopropyl ester group, dimethylamide group, diethylamide group, di-n-propylamide group, diisopropylamide group, acetyl group, propionyl group, butyryl group, isobutyryl group, dimethyl group Amino group, diethylamino group, di-n-propylamino group, diisopropyl Arylamino group, a sulfonic acid group, methylsulfonyl group, ethylsulfonyl group, n- propylsulfonyl group, isopropylsulfonyl group.

  Specific examples of the residue unit A represented by the general formula (1) include an α-cyano-2-hydroxycinnamate methyl residue unit and an α-cyano-3-hydroxycinnamate methyl residue unit. Α-cyano-4-hydroxy-methyl cinnamate residue unit, α-cyano-2,3-dihydroxymethyl cinnamate residue unit, α-cyano-3,4-dihydroxycinnamate methyl residue unit Α-cyano-2-carboxycinnamate methyl residue unit, α-cyano-3-carboxycinnamate methyl residue unit, α-cyano-4-carboxycinnamate methyl residue unit, α-cyano- 2,3-dicarboxycinnamate methyl residue unit, α-cyano-3,4-dicarboxycinnamate methyl residue unit, α-cyano-2-carboxy-3-hydroxycinnamate methyl residue unit , Α-Cyano-3-carbox 2-hydroxymethylcinnamate residue units, α-cyano-3-carboxy-4-hydroxycinnamate methyl residue units, α-cyano-4-carboxy-3-hydroxycinnamate methyl residue units, α-Cyano-2-carboxy-4-hydroxycinnamic acid methyl residue unit, α-cyano-4-carboxy-2-hydroxycinnamic acid methyl residue unit, α-cyano-2-hydroxycinnamic acid ethyl residue Group unit, ethyl α-cyano-3-hydroxycinnamate residue unit, ethyl α-cyano-4-hydroxycinnamate residue unit, ethyl α-cyano-2,3-dihydroxycinnamate residue unit, α-cyano-3,4-dihydroxycinnamic acid ethyl residue unit, α-cyano-2-carboxycinnamic acid ethyl residue unit, α-cyano-3-carboxycinnamic acid ethyl residue unit, α-si Ethyl 4-carboxycinnamate residue units, α-cyano-2,3-dicarboxyethyl cinnamate residue units, α-cyano-3,4-dicarboxycinnamate ethyl residue units, 3 -Hydroxy-α-cyano-2-carboxycinnamic acid ethyl residue unit, α-cyano-3-carboxy-2-hydroxycinnamic acid ethyl residue unit, α-cyano-3-carboxy-4-hydroxycinnamic leather unit Ethyl acid residue unit, α-cyano-4-carboxy-3-hydroxycinnamate ethyl residue unit, α-cyano-2-carboxy-4-hydroxycinnamic acid ethyl residue unit, α-cyano-4- Carboxy-2-hydroxycinnamic acid ethyl residue unit, α-cyano-2-hydroxycinnamic acid n-propyl residue unit, α-cyano-3-hydroxycinnamic acid n-propyl residue unit, α-cyano 4-hydroxycinnamic acid n-propyl residue unit, α-cyano-2,3-dihydroxycinnamic acid n-propyl residue unit, α-cyano-3,4-dihydroxycinnamic acid n-propyl residue unit Α-cyano-2-carboxycinnamic acid n-propyl residue unit, α-cyano-3-carboxycinnamic acid n-propyl residue unit, α-cyano-4-carboxycinnamic acid n-propyl residue unit Unit, α-cyano-2,3-dicarboxycinnamic acid n-propyl residue unit, α-cyano-3,4-dicarboxycinnamic acid n-propyl residue unit, α-cyano-2-carboxy- 3-hydroxycinnamic acid n-propyl residue unit, α-cyano-3-carboxy-2-hydroxycinnamic acid n-propyl residue unit, α-cyano-3-carboxy-4-hydroxycinnamic acid n- Single propyl residue , Α-cyano-4-carboxy-3-hydroxycinnamic acid n-propyl residue unit, α-cyano-2-carboxy-4-hydroxycinnamic acid n-propyl residue unit, α-cyano-4-carboxy 2-hydroxycinnamic acid n-propyl residue unit, α-cyano-2-hydroxycinnamic acid isopropyl residue unit, α-cyano-3-hydroxycinnamic acid isopropyl residue unit, α-cyano-4- Isopropyl hydroxycinnamate residue unit, α-cyano-2,3-dihydroxycinnamic acid isopropyl residue unit, α-cyano-3,4-dihydroxycinnamic acid isopropyl residue unit, α-cyano-2-carboxy Isopropyl cinnamate residue unit, α-cyano-3-carboxy isopropyl cinnamate residue unit, α-cyano-4-carboxy cinnamate isopropyl residue Position, isopropyl residue unit of α-cyano-2,3-dicarboxycinnamate, isopropyl residue unit of α-cyano-3,4-dicarboxycinnamate, α-cyano-2-carboxy-3-hydroxysilicate Isopropyl cinnamate residue unit, α-cyano-3-carboxy-2-hydroxycinnamate isopropyl residue unit, α-cyano-3-carboxy-4-hydroxycinnamate isopropyl residue unit, α-cyano-4 -Isopropyl carboxy-3-hydroxycinnamate residue unit, isopropyl residue α-cyano-2-carboxy-4-hydroxycinnamic acid residue, isopropyl residue α-cyano-4-carboxy-2-hydroxycinnamic acid Unit, α-cyano-2-hydroxycinnamic acid isobutyl residue unit, α-cyano-3-hydroxycinnamic acid isobutyl residue unit, α- Ano-4-hydroxycinnamic acid isobutyl residue unit, α-cyano-2,3-dihydroxycinnamic acid isobutyl residue unit, α-cyano-3,4-dihydroxycinnamic acid isobutyl residue unit, α-cyano 2-carboxycarboxycinnamate isobutyl residue unit, α-cyano-3-carboxycinnamate isobutyl residue unit, α-cyano-4-carboxycinnamate isobutyl residue unit, α-cyano-2,3- Isobutyl dicarboxycinnamate residue unit, α-cyano-3,4-dicarboxycinnamic acid isobutyl residue unit, α-cyano-2-carboxy-3-hydroxycinnamic acid isobutyl residue unit, α-cyano 3-carboxy-2-hydroxycinnamic acid isobutyl residue unit, α-cyano-3-carboxy-4-hydroxycinnamic acid isobutyl residue unit, α-cyano- -Carboxy-3-hydroxycinnamic acid isobutyl residue unit, α-cyano-2-carboxy-4-hydroxycinnamic acid isobutyl residue unit, α-cyano-4-carboxy-2-hydroxycinnamic acid isobutyl residue unit Unit, 2-hydroxybenzalmalononitrile residue unit, 3-hydroxybenzalmalononitrile residue unit, 4-hydroxybenzalmalononitrile residue unit, 2,3-dihydroxybenzalmalononitrile residue unit, 3, 4-dihydroxybenzalmalononitrile residue unit, 2-carboxybenzalmalononitrile residue unit, 3-carboxybenzalmalononitrile residue unit, 4-carboxybenzalmalononitrile residue unit, 2,3-dicarboxyl Benzalmalononitrile residue unit, 3,4-dicarboxybenzalmalonito Residue unit, 2-carboxy-3-hydroxybenzalmalononitrile residue unit, 3-carboxy-2-hydroxybenzalmalononitrile residue unit, 3-carboxy-4-hydroxybenzalmalononitrile residue unit, 4-carboxy-3-hydroxybenzalmalononitrile residue unit, 2-carboxy-4-hydroxybenzalmalononitrile residue unit, 4-carboxy-2-hydroxybenzalmalononitrile residue unit, 2-hydroxycinnamo Nitrile residue unit, 3-hydroxycinnamonitrile residue unit, 4-hydroxycinnamonitrile residue unit, 2-carboxycinnamonitrile residue unit, 3-carboxycinnamonitrile residue unit, 4-carboxycinnamo Nitrile residue unit, 2-hydroxychalcone residue unit, 3-hydride Xychalcone residue unit, 4-hydroxychalcone residue unit, 2-carboxychalcone residue unit, 3-carboxychalcone residue unit, 4-carboxychalcone residue unit, 2-hydroxybenzylidene malonate dimethyl residue unit, 3- Hydroxybenzylidene malonate dimethyl residue unit, 4-hydroxybenzylidene malonate dimethyl residue unit, 2-carboxybenzylidene malonate dimethyl residue unit, 3-carboxybenzylidene malonate dimethyl residue unit, 4-carboxybenzylidene malonate dimethyl residue Group unit, diethyl 2-hydroxybenzylidene malonate residue unit, diethyl 3-hydroxybenzylidene malonate residue unit, diethyl 4-hydroxybenzylidene malonate residue unit, 2-carboxybenzylidene malonate diethyl residue unit Position, diethyl 3-carboxybenzylidene malonate residue unit, diethyl 4-carboxybenzylidene malonate residue unit, 2-hydroxybenzylidene malonate di-n-propyl residue unit, 3-hydroxybenzylidene malonate di-n-propyl residue Unit, 4-hydroxybenzylidene malonate di n-propyl residue unit, 2-carboxybenzylidene malonate di n-propyl residue unit, 3-carboxybenzylidene malonate di n-propyl residue unit, 4-carboxybenzylidene malonate Di-n-propyl residue unit, 2-hydroxybenzylidene malonate diisopropyl residue unit, 3-hydroxybenzylidene malonate diisopropyl residue unit, 4-hydroxybenzylidene malonate diisopropyl residue unit, 2-carboxybenzylidene malonate diisopropyl residue unit Sopropyl residue unit, 3-carboxybenzylidene malonate diisopropyl residue unit, 4-carboxybenzylidene malonate diisopropyl residue unit, N, N-dimethyl-2-hydroxycinnamamide residue unit, N, N-dimethyl-3 -Hydroxycinnamamide residue unit, N, N-dimethyl-4-hydroxycinnamamide residue unit, N, N-dimethyl-2-carboxycinnamamide residue unit, N, N-dimethyl-3-carboxy Cinnamamide residue unit, N, N-dimethyl-4-carboxycinnamamide residue unit, N, N-diethyl-2-hydroxycinnamamide residue unit, N, N-diethyl-3-hydroxycinnam Amide residue unit, N, N-diethyl-4-hydroxycinnamamide residue unit, N, N-diethyl-2-carboxyl Boxicinnamamide residue unit, N, N-diethyl-3-carboxycinnamamide residue unit, N, N-diethyl-4-carboxycinnamamide residue unit, N, N-di-n-propyl-2 -Hydroxycinnamamide residue units, N, N-di-n-propyl-3-hydroxycinnamamide residue units, N, N-din-propyl-4-hydroxycinnamamide residue units, N, N -Di-n-propyl-2-carboxycinnamamide residue unit, N, N-di-n-propyl-3-carboxycinnamamide residue unit, N, N-di-n-propyl-4-carboxycinnamamide residue unit Residue unit, N, N-di-n-propyl-2-hydroxycinnamamide residue unit, N, N-di-n-propyl-3-hydroxycinnamamide residue unit, N, N-di-n-propyl -4- Hydroxycinnamamide residue unit, N, N-di-n-propyl-2-carboxycinnamamide residue unit, N, N-di-n-propyl-3-carboxycinnamamide residue unit, N, N- Di-n-propyl-4-carboxycinnamamide residue unit, N, N-diisopropyl-2-hydroxycinnamamide residue unit, N, N-diisopropyl-3-hydroxycinnamamide residue unit, N, N -Diisopropyl-4-hydroxycinnamamide residue unit, N, N-diisopropyl-2-carboxycinnamamide residue unit, N, N-diisopropyl-3-carboxycinnamamide residue unit, N, N-diisopropyl Examples include -4-carboxycinnamamide residue units. In this invention, 1 type of residue units A represented by General formula (1) may be contained, and multiple types may be contained.

  Among these, since high retardation and high compatibility with different polymers are expressed, α-cyano-4-hydroxycinnamic acid methyl residue unit, α-cyano-2-hydroxycinnamic acid ethyl residue unit, α-cyanoethyl residues such as α-cyano-3-hydroxycinnamate residue units, α-cyano-4-hydroxycinnamate ethyl residue units, α-cyano-2,4-dihydroxycinnamate methyl residue units, and the like. Cyano-hydroxycinnamic acid ester residue unit; α-cyano-4-carboxycinnamic acid methyl residue unit, α-cyano-4-carboxycinnamic acid ethyl residue unit, α-cyano-2,3-di Α-cyano-carboxycinnamic acid ester residue units such as methyl carboxycinnamate residue units and ethyl α-cyano-2,3-dicarboxycinnamate residue units; α-cyano-2-carboxy-3 − Α-cyano-carboxy-hydroxycinnamic acid ester residue units such as methyl droxycinnamate residue units and ethyl α-cyano-2-carboxy-3-hydroxycinnamate residue units; 4-hydroxybenzalmalononitrile Residual unit, hydroxybenzalmalononitrile residue unit such as 2,3-dihydroxy-benzalmalononitrile residue unit; 4-carboxybenzalmalononitrile residue unit, 2,3-dicarboxybenzalmalononitrile residue Carboxybenzalmalononitrile residue unit such as 2-carboxy-3-hydroxybenzalmalononitrile residue unit; Carboxy-hydroxybenzalmalononitrile residue unit such as 2-carboxy-3-hydroxybenzalmalononitrile residue unit; Hydroxycinnamonitrile residue unit; Namonitrile residue unit; hydroxychalcone residue unit; Hydroxybenzylidenemalonic acid diesters such as hydroxybenzylidenemalonate dimethyl residue units, hydroxybenzylidenemalonate diethyl residue units, hydroxybenzylidenemalonate di-n-propyl residue units, hydroxybenzylidenemalonate diisopropyl residue units Residue units: carboxybenzylidene malonate dimethyl residue units, carboxybenzylidene malonate diethyl residue units, carboxybenzylidene malonate di-n-propyl residue units, carboxybenzylidene malonate diisopropyl residue units, etc. Group unit; N, N-dimethyl-4-hydroxycinnamamide residue unit, N, N-diethyl-4-hydroxynamamide residue unit, N, N-di-n-pro N, N-dialkylhydroxycinnamamide residue units such as ru-4-hydroxycinnamamide residue units, N, N-diisopropyl-4-hydroxycinnamamide residue units; N, N-dimethyl-4- Carboxycinnamamide residue unit, N, N-diethyl-4-carboxynnamamide residue unit, N, N-di-n-propyl-4-carboxycinnamamide residue unit, N, N-diisopropyl-4- N, N-dialkylcarboxyxycinnamamide residue units such as carboxycinnamamide residue units are preferred, α-cyano-hydroxycinnamate residue units; hydroxybenzalmalononitrile residue units, α-cyano- Carboxycinnamic acid ester residue unit; carboxybenzalmalononitrile residue unit, hydroxybenzylidenemalo Diester residue units, more preferably carboxymethyl benzylidene malonic acid diester residue units.

R ₈ in the general formula (2) of the present invention represents an m-membered heterocyclic residue containing one or more heteroatoms, or a 5-membered or 6-membered cyclic residue containing no heteroatoms (provided that R ₈ When is a 6-membered ring residue containing no hetero atom, any one or more of R _{3 to} R ₇ in the general formula (1) represent a hydroxy group.), M represents an integer of 5 to 10. The m-membered heterocyclic residue, the 5-membered ring residue, and the 6-membered ring residue may form a condensed ring structure with another cyclic structure.

R ₈ in the general formula (2) of the present invention is preferably a 5-membered ring heterocyclic residue or a 6-membered ring heterocyclic residue containing one or more heteroatoms because a higher phase difference is expressed. More preferably, it is a 5-membered heterocyclic residue or a 6-membered heterocyclic residue containing one or more nitrogen atoms or oxygen atoms. Here, examples of the hetero atom when R ₈ in the general formula (2) of the present invention is the m-membered heterocyclic residue include a nitrogen atom, an oxygen atom, and a sulfur atom. When R ₈ is a 6-membered ring residue containing no hetero atom, the copolymer in which any one or more of R _{3 to} R ₇ in the general formula (1) is a hydroxy group is an effect according to the present invention. Are included in the present invention.

  Specific examples of the residue unit B represented by the general formula (2) include a 1-vinylpyrrole residue unit, a 2-vinylpyrrole residue unit, a 1-vinylindole residue unit, and a 9-vinylcarbazole residue. Base unit, 2-vinylquinoline residue unit, 4-vinylquinoline residue unit, 1-vinylisoquinoline residue unit, 2-vinylpyridine residue unit, 3-vinylpyridine residue unit, 4-vinylpyridine residue unit 1-vinylimidazole residue unit, 2-vinylimidazole residue unit, 4-vinylimidazole residue unit, 5-vinyl-2-pyrazoline residue unit, 2-vinylpyrazine residue unit, vinyl-s-triazine residue Group unit, 10-vinyl-9-hydroacridine residue unit, 1-vinyltetrazole residue unit, 5-vinyltetrazole residue unit, N-vinylpyrrolide Residue unit, N-vinyl-ε-caprolactam residue unit, N-vinylsuccinimide residue unit, N-vinylphthalimide residue unit, N-vinylsaccharin residue unit, 2-vinylfuran residue unit, 3-vinyl Furan residue unit, 2-vinylbenzofuran residue unit, 2-vinylthiophene residue unit, 3-vinylthiophene residue unit, 2-vinylbenzothiophene residue unit, 2-vinylbenzoxazole residue unit, N-vinyl Examples thereof include an oxazolidone residue unit, a 2-vinylthiazole residue unit, a 2-vinylbenzothiazole residue unit, a styrene residue unit, a 2-vinylnaphthalene residue unit, and a substituent adduct thereof. In this invention, 1 type of residue units B represented by General formula (2) may be contained, and multiple types may be contained.

  Among these, since a high phase difference is expressed, a 1-vinylpyrrole residue unit, a 2-vinylpyrrole residue unit, a 1-vinylindole residue unit, a 9-vinylcarbazole residue unit, a 2-vinylquinoline residue Group unit, 4-vinylquinoline residue unit, N-vinylphthalimide residue unit, N-vinylsuccinimide residue unit, 2-vinylfuran residue unit, 2-vinylbenzofuran residue unit, styrene residue unit, 2- A vinylnaphthalene residue unit is preferable, and a 9-vinylcarbazole residue unit and an N-vinylphthalimide residue unit are more preferable.

R ₉ and R ₁₀ in the general formula (3) of the present invention are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or 3 to 6 carbon atoms. Of the cyclic alkyl group.

Examples of the linear alkyl group having 1 to 12 carbon atoms in R ₉ and R ₁₀ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the branched alkyl group having 1 to 12 carbon atoms include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group and the like, and examples of the cyclic alkyl group having 3 to 6 carbon atoms include , Cyclopropyl group, cyclobutyl group, cyclohexyl group and the like.

In the general formula (3) of the present invention, R ₉ and R ₁₀ are the ratios Re (450) / Re between the in-plane retardation (Re) at a light wavelength of 450 nm and the in-plane retardation (Re) at a light wavelength of 550 nm. Since (550) is good, hydrogen, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, isobutyl group, pentyl group, isopentyl group, sec-pentyl group, 3 -Pentyl group, neopentyl group, hexyl group, isohexyl group, neohexyl group are preferable, hydrogen, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, isobutyl group are Further preferred.

  Specific examples of the residue unit C represented by the general formula (3) include an acrylic acid residue unit, a methacrylic acid residue unit, a 2-ethylacrylic acid residue unit, and a 2-propylacrylic acid residue unit. 2-isopropyl acrylate residue unit, 2-pentyl acrylate residue unit, 2-hexyl acrylate residue unit, methyl acrylate residue unit, ethyl acrylate residue unit, propyl acrylate residue unit, acrylic Isopropyl residue unit, butyl acrylate residue unit, isobutyl acrylate residue unit, sec-butyl acrylate residue unit, pentyl acrylate residue unit, isopentyl acrylate residue unit, sec-pentyl acrylate residue Unit, 3-pentyl acrylate residue unit, neopentyl acrylate residue unit, hexyl acrylate residue unit, isoacrylate acrylate Xylyl residue unit, neohexyl acrylate residue unit, methyl methacrylate residue unit, ethyl methacrylate residue unit, propyl methacrylate residue unit, isopropyl methacrylate residue unit, butyl methacrylate residue unit, methacryl Isobutyl residue unit, sec-butyl methacrylate unit, pentyl methacrylate unit, isopentyl methacrylate unit, sec-pentyl methacrylate unit, 3-pentyl methacrylate unit, neopentyl methacrylate Residue unit, hexyl methacrylate residue unit, isohexyl methacrylate residue unit, neohexyl methacrylate residue unit, methyl 2-ethyl acrylate residue unit, ethyl 2-ethyl acrylate residue unit, 2-ethyl acrylate residue unit, 2-ethyl acrylate Propyl residue unit, 2-ethyl butyl acrylate residue unit, 2-ethyl acrylate, isobutyl residue unit, and 2-ethyl acrylate sec- butyl residue unit and the like.

  Among these, since the ratio Re (450) / Re (550) between the in-plane retardation (Re) at a light wavelength of 450 nm and the in-plane retardation (Re) at a light wavelength of 550 nm is good, methyl acrylate Residue unit, ethyl acrylate residue unit, propyl acrylate residue unit, isopropyl acrylate residue unit, butyl acrylate residue unit, isobutyl acrylate residue unit, sec-butyl acrylate residue unit, methacrylic acid Methyl residue unit, ethyl methacrylate residue unit, propyl methacrylate residue unit, isopropyl methacrylate residue unit, butyl methacrylate residue unit, isobutyl methacrylate residue unit, sec-butyl methacrylate residue unit, methacryl Acid methyl residue units, ethyl methacrylate residue units, propyl methacrylate residue units, Isopropyl crylate residue units, butyl methacrylate residue units, isobutyl methacrylate residue units, sec-butyl methacrylate residue units are preferred, methyl methacrylate residue units, ethyl methacrylate residue units, propyl methacrylate residue More preferred are a base unit, an isopropyl methacrylate residue unit, a butyl methacrylate residue unit, an isobutyl methacrylate residue unit, and a sec-butyl methacrylate residue unit.

  The copolymer of the present invention comprises a residue unit A represented by the general formula (1), a residue unit B represented by the general formula (2), and a residue unit C represented by the general formula (3). Although it is not particularly limited as long as it is included, it exhibits favorable compatibility and is more suitable for facilitating complexation with a different polymer, so that α-cyano-2-hydroxycinnamic acid ester-styrene- Acrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-2-vinylnaphthalene-acrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-1-vinylindole-acrylic acid Ester copolymer, α-cyano-2-hydroxycinnamic acid ester-9-vinylcarbazole-acrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-N-vinylsuccin Imido-acrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-N-vinylphthalimide-acrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-2-vinyl furan- Acrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-2-vinylbenzofuran-acrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-styrene-acrylic acid ester copolymer, 2- Hydroxybenzalmalononitrile-2-vinylnaphthalene-acrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-1-vinylindole-acrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-9-vinylcarbazole -Acrylate ester copolymer, 2-hydride Xibenzalmalononitrile-N-vinylsuccinimide-acrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-N-vinylphthalimide-acrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-2-vinylfuran -Acrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-2-vinylbenzofuran-acrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-styrene-acrylic acid ester copolymer, α -Cyano-3-hydroxycinnamic acid ester-2-vinylnaphthalene-acrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-1-vinylindole-acrylic acid ester copolymer, α-cyano -3-Hydroxycinnamic ester-9-vini Rucarbazole-acrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-N-vinylsuccinimide-acrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-N-vinylphthalimide -Acrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-2-vinylfuran-acrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-2-vinylbenzofuran-acrylic Acid ester copolymer, 3-hydroxybenzalmalononitrile-styrene-acrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-2-vinylnaphthalene-acrylic acid ester copolymer, 3-hydroxybenzalmalononitrile -1-vinylindole-acrylic acid ester 3-hydroxybenzalmalononitrile-9-vinylcarbazole-acrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-N-vinylsuccinimide-acrylic acid ester copolymer, 3-hydroxybenzalmalononitrile- N-vinylphthalimide-acrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-2-vinylfuran-acrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-2-vinylbenzofuran-acrylic acid ester copolymer 4-hydroxy-α-cyanocinnamic acid ester-styrene-acrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-2-vinylnaphthalene-acrylic acid ester copolymer, α-cyano- 4-hydroxycinnamic acid esthetic 1-vinylindole-acrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-9-vinylcarbazole-acrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester N-vinylsuccinimide-acrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-N-vinylphthalimide-acrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-2- Vinylfuran-acrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-2-vinylbenzofuran-acrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-styrene-acrylic acid ester copolymer 4-hydroxybenzalmalononitrile-2-vinylnaphthalene-acrylic Rylic acid ester copolymer, 4-hydroxybenzalmalononitrile-1-vinylindole-acrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-9-vinylcarbazole-acrylic acid ester copolymer, 4-hydroxy Benzalmalononitrile-N-vinylsuccinimide-acrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-N-vinylphthalimide-acrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-2-vinylfuran- Acrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-2-vinylbenzofuran-acrylic acid ester copolymer, 2-hydroxy-α-cyanocinnamic acid ester-styrene-methacrylic acid ester copolymer, 2-hydroxy -Α-cyano Cinnamic acid ester-2-vinylnaphthalene-methacrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-1-vinylindole-methacrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid Acid ester-9-vinylcarbazole-methacrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-N-vinylsuccinimide-methacrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester -N-vinylphthalimide-methacrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-2-vinylfuran-methacrylic acid ester copolymer, α-cyano-2-hydroxycinnamic acid ester-2 -Vinylbenzofuran-methacrylic acid ester copolymer, 2-hydroxyben Lumalononitrile-styrene-methacrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-2-vinylnaphthalene-methacrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-1-vinylindole-methacrylic acid ester copolymer Polymer, 2-hydroxybenzalmalononitrile-9-vinylcarbazole-methacrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-N-vinylsuccinimide-methacrylic acid ester copolymer, 2-hydroxybenzalmalononitrile -N-vinylphthalimide-methacrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-2-vinylfuran-methacrylic acid ester copolymer, 2-hydroxybenzalmalononitrile-2-vinylbenzofuran- Tacrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-styrene-methacrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-2-vinylnaphthalene-methacrylic acid ester copolymer , Α-cyano-3-hydroxycinnamic acid ester-1-vinylindole-methacrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-9-vinylcarbazole-methacrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-N-vinylsuccinimide-methacrylic acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-N-vinylphthalimide-methacrylic acid ester copolymer, α- Cyano-3-hydroxycinnamic acid ester-2-vinylfuran-methacrylic acid Acid ester copolymer, α-cyano-3-hydroxycinnamic acid ester-2-vinylbenzofuran-methacrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-styrene-methacrylic acid ester copolymer, 3-hydroxy Benzalmalononitrile-2-vinylnaphthalene-methacrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-1-vinylindole-methacrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-9-vinylcarbazole- Methacrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-N-vinylsuccinimide-methacrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-N-vinylphthalimide-methacrylic acid ester copolymer, 3-hydroxy Sibenzalmalononitrile-2-vinylfuran-methacrylic acid ester copolymer, 3-hydroxybenzalmalononitrile-2-vinylbenzofuran-methacrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester— Styrene-methacrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-2-vinylnaphthalene-methacrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-1-vinylindole- Methacrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-9-vinylcarbazole-methacrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-N-vinylsuccinimide-methacrylic acid Ester copolymer, α-cyano-4-hydroxysil Acid ester-N-vinylphthalimide-methacrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester-2-vinylfuran-methacrylic acid ester copolymer, α-cyano-4-hydroxycinnamic acid ester 2-vinylbenzofuran-methacrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-styrene-methacrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-2-vinylnaphthalene-methacrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-1-vinylindole-methacrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-9-vinylcarbazole-methacrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-N- Vinyl succinimi -Methacrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-N-vinylphthalimide-methacrylic acid ester copolymer, 4-hydroxybenzalmalononitrile-2-vinylfuran-methacrylic acid ester copolymer, 4- Hydroxybenzalmalononitrile-2-vinylbenzofuran-methacrylate copolymer is preferred.

  Further, the copolymer of the present invention includes a residue unit A represented by the general formula (1) and a residue unit C represented by the general formula (3) in order to express good optical properties, Furthermore, the residue unit B is preferably a residue unit represented by the general formula (4) and / or the general formula (5).

(Here, R _{11 to} R ₁₈ are each independently hydrogen, halogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, A cyano group, a nitro group, a hydroxy group, a carboxy group, a thiol group, an alkoxy group (—OX ₁₃ ), an ester group (—C (═O) OX ₁₄ or —CO (═O) —X ₁₅ ), an amide group (— C (═O) N (X ₁₆ ) (X ₁₇ ) or —NX ₁₈ C (═O) X ₁₉ ), acyl group (—C (═O) X ₂₀ ) or amino group (—N (X ₂₁ ) ( X ₂₂ )) (where X _{13 to} X ₁₅ are each independently a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms. X _{16 to} X ₂₂ each independently represent hydrogen or carbon number A linear alkyl group having 1 to 12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms.), And R _{11 to} R ₁₈ are adjacent to each other. And a condensed ring structure may be formed, and R ₁₁ and R ₁₇ and R ₁₂ and R ₁₈ may form a ring structure with the same atom.)

(Here, R _{19 to} R ₂₂ are each independently hydrogen, halogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, Cyano group, nitro group, hydroxy group, carboxy group, thiol group, alkoxy group (—OX ₂₃ ), ester group (—C (═O) OX ₂₄ or —CO (═O) —X ₂₅ ), amide group (— C (═O) N (X ₂₆ ) (X ₂₇ ) or —NX ₂₈ C (═O) X ₂₉ ), acyl group (—C (═O) X ₃₀ ) or amino group (—N (X ₃₁ ) ( X ₃₂ )) (where X _{23 to} X ₂₅ are each independently a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms. X _{26 to} X ₃₂ each independently represent hydrogen or carbon number. A linear alkyl group having 1 to 12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms.) And R _{19 to} R ₂₂ are adjacent to each other. And a condensed ring structure may be formed, and R ₁₉ and R ₂₀ and R ₂₁ and R ₂₂ may be the same atom and may form a ring structure.)
R _{11 to} R ₁₈ in the general formula (4) in the present invention are each independently hydrogen, halogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or 3 to 3 carbon atoms. 14 cyclic groups, cyano group, nitro group, hydroxy group, carboxy group, thiol group, alkoxy group (—OX ₁₃ ), ester group (—C (═O) OX ₁₄ or —CO (═O) —X ₁₅ ) , An amide group (—C (═O) N (X ₁₆ ) (X ₁₇ ) or —NX ₁₈ C (═O) X ₁₉ ), an acyl group (—C (═O) X ₂₀ ) or an amino group (—N (X ₂₁ ) (X ₂₂ )) (where X _{13 to} X ₁₅ are each independently a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or the number of carbon atoms. 3 to 14 cyclic groups, X _{16 to} X ₂₂ are Each independently represents hydrogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms). R _{11 to} R ₁₈ may form a condensed ring structure with adjacent substituents, and R ₁₁ and R ₁₇ and R ₁₂ and R ₁₈ may be the same atom and may form a ring structure. .

Examples of the halogen in R _{11 to} R ₁₈ include fluorine, chlorine, bromine and the like, and examples of the linear alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, Examples thereof include linear alkyl groups having 1 to 12 carbon atoms such as pentyl group and hexyl group. Examples of branched alkyl groups having 1 to 12 carbon atoms include isopropyl group, isobutyl group, sec-butyl group, tert- Examples thereof include branched alkyl groups having 1 to 12 carbon atoms such as a butyl group. Examples of the cyclic group having 3 to 14 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclopentanyl group, and a phenyl group. Group, naphthyl group, anthryl group, furyl group, pyranyl group, pyrrolyl group, imidazolyl group, pyridyl group, indolyl group, carbazolyl group Specific examples of the alkoxy group include a methoxy group and an ethoxy group, and specific ester groups include, for example, a methyloxycarbonyl group, ethyloxy group, and the like. Examples include carbonyl group, acetoxy group, propoxy group, and the like. Specific examples of the amide group include dimethylamide group and diethylamide group. Specific examples of the acyl group include acetyl group, propionyl group, and the like. A benzoyl group etc. are mentioned, As a specific amino group, a dimethylamino group, a diethylamino group, etc. are mentioned.

Examples of the linear alkyl group having 1 to 12 carbon atoms in X _{13 to} X ₂₂ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the branched alkyl group having 1 to 12 carbon atoms include isopropyl group, sec-butyl group, tert-butyl group, isobutyl group and the like, and examples of the cyclic group having 3 to 14 carbon atoms include: A cyclopropyl group, a cyclobutyl group, a cyclohexyl group, a phenyl group, a naphthyl group, etc. are mentioned.

  Specific examples of the residue unit represented by the general formula (4) include indole residue units such as an N-vinylindole residue unit and an N-methyl-3-vinylindole residue unit; 9 Examples include 9-vinylcarbazole residue units such as -vinylcarbazole residue units, 3-methyl-N-vinylcarbazole, and 3-chloro-N-vinylcarbazole. Among these, a 9-vinylcarbazole residue unit is preferable, and a 9-vinylcarbazole residue unit is more preferable in order to develop a higher negative retardation and higher compatibility with different polymers.

R _{19 to} R ₂₂ in the general formula (5) in the present invention are each independently hydrogen, halogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or 3 to 3 carbon atoms. 14 cyclic groups, cyano group, nitro group, hydroxy group, carboxy group, thiol group, alkoxy group (—OX ₂₃ ), ester group (—C (═O) OX ₂₄ or —CO (═O) —X ₂₅ ) An amide group (—C (═O) N (X ₂₆ ) (X ₂₇ ) or —NX ₂₈ C (═O) X ₂₉ ), an acyl group (—C (═O) X ₃₀ ) or an amino group (—N (X ₃₁ ) (X ₃₂ )) (where X _{23 to} X ₂₅ are each independently a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or the number of carbon atoms. 3 to 14 cyclic groups, X _{26 to} X ₃₂ are Each independently represents hydrogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms). R _{19 to} R ₂₂ may form a condensed ring structure with adjacent substituents, and R ₁₉ and R ₂₀ and R ₂₁ and R ₂₂ may be the same atom to form a ring structure. .

Examples of the halogen in R _{19 to} R ₂₂ include fluorine, chlorine, bromine and the like, and examples of the linear alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, Examples thereof include linear alkyl groups having 1 to 12 carbon atoms such as pentyl group and hexyl group. Examples of branched alkyl groups having 1 to 12 carbon atoms include isopropyl group, isobutyl group, sec-butyl group, tert- Examples thereof include branched alkyl groups having 1 to 12 carbon atoms such as a butyl group. Examples of the cyclic group having 3 to 14 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclopentanyl group, and a phenyl group. Group, naphthyl group, anthryl group, furyl group, pyranyl group, pyrrolyl group, imidazolyl group, pyridyl group, indolyl group, carbazolyl group Specific examples of the alkoxy group include a methoxy group and an ethoxy group, and specific ester groups include, for example, a methyloxycarbonyl group, ethyloxy group, and the like. Examples include carbonyl group, acetoxy group, propoxy group, and the like. Specific examples of the amide group include dimethylamide group and diethylamide group. Specific examples of the acyl group include acetyl group, propionyl group, and the like. A benzoyl group etc. are mentioned, As a specific amino group, a dimethylamino group, a diethylamino group, etc. are mentioned.

Examples of the linear alkyl group having 1 to 12 carbon atoms in X ₂₃ to X _32, for example, mentioned a methyl group, an ethyl group, n- propyl group, n- butyl group, n- pentyl group, n- hexyl and the like Examples of the branched alkyl group having 1 to 12 carbon atoms include isopropyl group, sec-butyl group, tert-butyl group, isobutyl group and the like, and examples of the cyclic group having 3 to 14 carbon atoms include: A cyclopropyl group, a cyclobutyl group, a cyclohexyl group, a phenyl group, a naphthyl group, etc. are mentioned.

  Specific examples of the residue unit represented by the general formula (5) include N-vinylsuccinimide residue units such as N-vinylsuccinimide residue units; N-vinylphthalimide residue units, 4- N-vinylphthalimide residue units such as methylphthalimide residue units, 4-chloromethylphthalimide residue units, 4-nitrophthalimide residue units; N-vinyl 2,3-naphthalenedicarboximide residue units, N- Examples thereof include N-vinylnaphthalenedicarboximides such as vinyl 1,8-naphthalenedicarboximide residue units. Among these, N-vinylphthalimide residue units are preferable, and N-vinylphthalimide residue units are more preferable in order to express higher negative retardation and higher compatibility with different polymers.

  The copolymer of the present invention may contain other monomer residue units as long as the scope of the present invention is not exceeded. Examples of other monomer residue units include α-methylstyrene. Residue units, styrene residue units such as trans-stilbene; vinyl ester residue units such as vinyl acetate residue units and vinyl propionate residue units; acrylonitrile residue units; methacrylonitrile residue units; methyl vinyl ether Residue units, vinyl ether residue units such as ethyl vinyl ether residue units, butyl vinyl ether residue units; diethyl fumarate residue units, fumarate ester residue units; N-methylmaleimide residue units, N-cyclohexylmaleimide residues N-substituted maleimide residue units such as group units and N-phenylmaleimide residue units; ethylene residue units, propylene residue units, etc. Mention may be made of one or more members selected from olefins residue unit and the like.

  Since the composition of the copolymer of the present invention has excellent retardation characteristics when used as a retardation film, it is represented by the residue unit A represented by the general formula (1) and the general formula (2). The molar ratio A / B to the residue unit B is preferably 0.05 to 6, more preferably 0.1 to 3, particularly preferably 0.18 to 2, Most preferred is 25-1.

  The composition of the copolymer of the present invention has a good ratio Re (450) / Re (550) between the in-plane retardation (Re) at a light wavelength of 450 nm and the in-plane retardation (Re) at a light wavelength of 550 nm. Therefore, the molar ratio A / C between the residue unit A represented by the general formula (1) and the residue unit C represented by the general formula (3) is preferably 0.02 to 50, More preferably, it is 0.1-25, It is especially preferable that it is 0.25-20, It is most preferable that it is 0.5-15.

  Among the copolymers of the present invention, the copolymer in which the residue unit B is a residue unit B other than the residue unit represented by the general formula (4) is excellent in mechanical properties. The number average molecular weight in terms of standard polystyrene obtained from an elution curve measured by gel permeation chromatography (GPC) is preferably 3,000 to 500,000, more preferably 5,000 to 400,000. More preferred is 10,000 to 300,000. Among the copolymers of the present invention, the copolymer in which the residue unit B is the residue unit represented by the general formula (4) is excellent in mechanical properties, and therefore gel permeation. The number average molecular weight in terms of standard pullulan obtained from an elution curve measured by chromatography (GPC) is preferably 3,000 to 500,000, more preferably 5,000 to 400,000. 000 to 300,000 is particularly preferable.

  The glass transition temperature of the copolymer of the present invention is preferably 150 ° C. or higher, more preferably 170 ° C. or higher, since the phase difference characteristics when the retardation film is obtained are excellent. It is especially preferable that it is 180 degreeC or more.

  Although there is no restriction | limiting in particular about the manufacturing method of the polymer of this invention, For example, the manufacturing method superposed | polymerized using the monomer represented by General formula (6) is mentioned.

(Here, R ₁ and R ₂ are each independently hydrogen (except when R ₁ and R ₂ are both hydrogen), a cyano group, an ester group (—C (═O) OX ₁ ), An amide group (—C (═O) N (X ₂ ) (X ₃ )), or an acyl group (—C (═O) X ₄ ) (where X _{1 to} X ₃ each independently represents 1 carbon atom) 12 linear alkyl group, branched alkyl group having 1 to 12 carbon atoms, or cyclic alkyl group having 3 to 6 carbon atoms, _{X 4} is a linear alkyl group having 1 to 12 carbon atoms, carbon atoms R _{3 to} R ₇ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, carbon, and a branched alkyl group having 1 to 12 carbon atoms or a cyclic group having ₃ to 14 carbon atoms. A branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, halogen, hydroxy group, carboxy group, nitro , A cyano group, an alkoxy group _(-OX 5), an ester group _{(-C (= O) OX 6} ), an amide group _{(-C (= O) N (} X 7) (X 8)), an acyl group (-C (═O) X ₉ ), an amino group (—N (X ₁₀ ) (X ₁₁ )), or a sulfonic acid group (—SOOX ₁₂ ) (where X _{5 to} X ₈ each independently represent 1 carbon atom) Represents a linear alkyl group having ˜12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, and X _{9 to} X ₁₂ are each independently hydrogen, 1 to 12 carbon atoms. A straight-chain alkyl group, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.), Wherein at least one of R _{3 to} R ₇ is a hydroxy group or a carboxy group It is shown. in addition, R ₃ to R ₇ may form a fused ring structure adjacent substituents It may be.)
Specific monomers in the general formula (6) of the present invention include, for example, methyl α-cyano-2-hydroxycinnamate, methyl α-cyano-3-hydroxycinnamate, α-cyano-4- Hydroxy-methyl cinnamate, methyl α-cyano-2,3-dihydroxycinnamate, methyl α-cyano-3,4-dihydroxycinnamate, methyl α-cyano-2-carboxycinnamate, α-cyano -3-methyl carboxycinnamate, methyl α-cyano-4-carboxycinnamate, methyl α-cyano-2,3-dicarboxycinnamate, methyl α-cyano-3,4-dicarboxycinnamate , Α-cyano-2-carboxy-3-hydroxycinnamic acid methyl, α-cyano-3-carboxy-2-hydroxycinnamic acid methyl, α-cyano-3-carboxy-4-hydroxycinnamic acid , Methyl α-cyano-4-carboxy-3-hydroxycinnamate, methyl α-cyano-2-carboxy-4-hydroxycinnamate, methyl α-cyano-4-carboxy-2-hydroxycinnamate, ethyl α-cyano-2-hydroxycinnamate, ethyl α-cyano-3-hydroxycinnamate, ethyl α-cyano-4-hydroxycinnamate, ethyl α-cyano-2,3-dihydroxycinnamate, α-cyano-3,4-dihydroxycinnamate ethyl, α-cyano-2-carboxycinnamate ethyl, α-cyano-3-carboxycinnamate ethyl, α-cyano-4-carboxycinnamate ethyl, α-cyano-2,3-dicarboxycinnamic acid ethyl, α-cyano-3,4-dicarboxycinnamic acid ethyl, 3-hydroxy-α-cyano-2-carboxycinnamic acid , Ethyl α-cyano-3-carboxy-2-hydroxycinnamate, ethyl α-cyano-3-carboxy-4-hydroxycinnamate, ethyl α-cyano-4-carboxy-3-hydroxycinnamate, α-cyano-2-carboxy-4-hydroxycinnamic acid ethyl, α-cyano-4-carboxy-2-hydroxycinnamic acid ethyl, α-cyano-2-hydroxycinnamic acid n-propyl, α-cyano- N-propyl 3-hydroxycinnamate, n-propyl α-cyano-4-hydroxycinnamate, n-propyl α-cyano-2,3-dihydroxycinnamate, α-cyano-3,4-dihydroxycin N-propyl cinnamate, n-propyl α-cyano-2-carboxycinnamate, n-propyl α-cyano-3-carboxycinnamate, α-cyano-4-carboxycinnamic hide n-propyl, α-cyano-2,3-dicarboxycinnamic acid n-propyl, α-cyano-3,4-dicarboxycinnamic acid n-propyl, α-cyano-2-carboxy-3-hydroxysilicic acid N-propyl cinnamate, n-propyl α-cyano-3-carboxy-2-hydroxycinnamate, n-propyl α-cyano-3-carboxy-4-hydroxycinnamate, α-cyano-4-carboxy- 3-hydroxycinnamic acid n-propyl, α-cyano-2-carboxy-4-hydroxycinnamic acid n-propyl, α-cyano-4-carboxy-2-hydroxycinnamic acid n-propyl, α-cyano- Isopropyl 2-hydroxycinnamate, isopropyl α-cyano-3-hydroxycinnamate, isopropyl α-cyano-4-hydroxycinnamate, α-cyano-2,3-di Isopropyl droxycinnamate, isopropyl α-cyano-3,4-dihydroxycinnamate, isopropyl α-cyano-2-carboxycinnamate, isopropyl α-cyano-3-carboxycinnamate, α-cyano-4-carboxy Isopropyl cinnamate, isopropyl α-cyano-2,3-dicarboxycinnamate, isopropyl α-cyano-3,4-dicarboxycinnamate, isopropyl α-cyano-2-carboxy-3-hydroxycinnamate , Α-cyano-3-carboxy-2-hydroxycinnamic acid isopropyl, α-cyano-3-carboxy-4-hydroxycinnamic acid isopropyl, α-cyano-4-carboxy-3-hydroxycinnamic acid isopropyl, α -Isocyano-2-carboxy-4-hydroxycinnamate, α-cyano-4-ca Isopropyl ruboxoxy-2-hydroxycinnamate, isobutyl α-cyano-2-hydroxycinnamate, isobutyl α-cyano-3-hydroxycinnamate, isobutyl α-cyano-4-hydroxycinnamate, α-cyano- Isobutyl 2,3-dihydroxycinnamate, isobutyl α-cyano-3,4-dihydroxycinnamate, isobutyl α-cyano-2-carboxycinnamate, isobutyl α-cyano-3-carboxycinnamate, α- Isobutyl cyano-4-carboxycinnamate, isobutyl α-cyano-2,3-dicarboxycinnamate, isobutyl α-cyano-3,4-dicarboxycinnamate, α-cyano-2-carboxy-3- Isobutyl hydroxycinnamate, isobutyl α-cyano-3-carboxy-2-hydroxycinnamate, α-cyano-3-cal Isobutyl xyl-4-hydroxycinnamate, isobutyl α-cyano-4-carboxy-3-hydroxycinnamate, isobutyl α-cyano-2-carboxy-4-hydroxycinnamate, α-cyano-4-carboxy- Isobutyl 2-hydroxycinnamate, 2-hydroxybenzalmalononitrile, 3-hydroxybenzalmalononitrile, 4-hydroxybenzalmalononitrile, 2,3-dihydroxybenzalmalononitrile, 3,4-dihydroxybenzalmalonono Nitrile, 2-carboxybenzalmalononitrile, 3-carboxybenzalmalononitrile, 4-carboxybenzalmalononitrile, 2,3-dicarboxybenzalmalononitrile, 3,4-dicarboxybenzalmalononitrile, 2- Carboxy-3-hydroxybenzal Malononitrile, 3-carboxy-2-hydroxybenzalmalononitrile, 3-carboxy-4-hydroxybenzalmalononitrile, 4-carboxy-3-hydroxybenzalmalononitrile, 2-carboxy-4-hydroxybenzalmalononitrile, 4-carboxy-2-hydroxybenzalmalononitrile, 2-hydroxycinnamonitrile, 3-hydroxycinnamonitrile, 4-hydroxycinnamonitrile, 2-carboxycinnamonitrile, 3-carboxycinnamonitrile, 4-carboxy Cinnamonitrile, 2-hydroxychalcone, 3-hydroxychalcone, 4-hydroxychalcone, 2-carboxychalcone, 3-carboxychalcone, 4-carboxychalcone, dimethyl-2-hydroxybenzylidenemalonate, -Dimethylhydroxybenzylidenemalonate, dimethyl 4-hydroxybenzylidenemalonate, 2-carboxybenzylidenemalonate dimethyl, 3-carboxybenzylidenemalonate dimethyl, 4-carboxybenzylidenemalonate dimethyl, 2-hydroxybenzylidenemalonate, 3-hydroxy Diethyl benzylidenemalonate, diethyl 4-hydroxybenzylidenemalonate, diethyl 2-carboxybenzylidenemalonate, diethyl 3-carboxybenzylidenemalonate, diethyl 4-carboxybenzylidenemalonate, di-n-propyl-2-hydroxybenzylidenemalonate, 3- Hydroxybenzylidenemalonate di n-propyl, 4-hydroxybenzylidenemalonate din-propyl, 2-carboxybenzylidenemalon Di-n-propyl, di-n-propyl 3-carboxybenzylidenemalonate, di-n-propyl 4-carboxybenzylidenemalonate, diisopropyl 2-hydroxybenzylidenemalonate, diisopropyl 3-hydroxybenzylidenemalonate, diisopropyl 4-hydroxybenzylidenemalonate 2-carboxybenzylidenemalonate diisopropyl, 3-carboxybenzylidenemalonate diisopropyl, 4-carboxybenzylidenemalonate diisopropyl, N, N-dimethyl-2-hydroxycinnamamide, N, N-dimethyl-3-hydroxycinnamamide N, N-dimethyl-4-hydroxycinnamamide, N, N-dimethyl-2-carboxycinnamamide, N, N-dimethyl-3-carboxycinnamamide, N, N-di Methyl-4-carboxycinnamamide, N, N-diethyl-2-hydroxycinnamamide, N, N-diethyl-3-hydroxycinnamamide, N, N-diethyl-4-hydroxycinnamamide, N, N-diethyl-2-carboxycinnamamide, N, N-diethyl-3-carboxycinnamamide, N, N-diethyl-4-carboxycinnamamide, N, N-di-n-propyl-2-hydroxycin Namamide, N, N-Di-n-propyl-3-hydroxycinnamamide, N, N-Di-n-propyl-4-hydroxycinnamamide, N, N-Di-n-propyl-2-carboxycinnamamide N, N-di-n-propyl-3-carboxycinnamamide, N, N-di-n-propyl-4-carboxycinnamamide, N, N-din-amide Pyr-2-hydroxycinnamamide, N, N-di-n-propyl-3-hydroxycinnamamide, N, N-di-n-propyl-4-hydroxycinnamamide, N, N-di-n-propyl- 2-carboxycinnamamide, N, N-di-n-propyl-3-carboxycinnamamide, N, N-di-n-propyl-4-carboxycinnamamide, N, N-diisopropyl-2-hydroxycinnam Amide, N, N-diisopropyl-3-hydroxycinnamamide, N, N-diisopropyl-4-hydroxycinnamamide, N, N-diisopropyl-2-carboxycinnamamide, N, N-diisopropyl-3-carboxy Examples thereof include cinnamamide and N, N-diisopropyl-4-carboxycinnamamide. By polymerizing these monomers, a polymer can be obtained without performing complicated post-reactions such as deprotection.

  Specific production methods of the copolymer of the present invention include a residue unit A represented by the general formula (1), a residue unit B represented by the general formula (2), and a general formula (3). As long as the copolymer containing the residue unit C is obtained, it may be produced by any method, for example, by radical polymerization.

  As the radical polymerization, a known polymerization method can be employed. For example, any of a bulk polymerization method, a solution polymerization method, a suspension polymerization method, a precipitation polymerization method, and an emulsion polymerization method can be employed.

  Examples of the polymerization initiator used for radical polymerization include benzoyl peroxide, lauryl peroxide, octanoyl peroxide, acetyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide. , Organic peroxides such as t-butylperoxyacetate, t-butylperoxybenzoate, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane; 2,2′-azobis ( 2,4-dimethylvaleronitrile), 2,2′-azobis (2-butyronitrile), 2,2′-azobisisobutyronitrile, dimethyl-2′-azobisisobutyrate, 1,1′-azobis And azo initiators such as (cyclohexane-1-carbonitrile).

  And there is no restriction | limiting in particular as a solvent which can be used when employ | adopting solution polymerization method, suspension polymerization method, precipitation polymerization method, and emulsion polymerization method, For example, aromatic solvents, such as benzene, toluene, xylene; methanol, ethanol, Alcohol solvents such as propanol and butanol; cyclohexane; dioxane; tetrahydrofuran; acetone; methyl ethyl ketone; N, N-dimethylformamide; dimethyl sulfoxide; isopropyl acetate; water and the like.

  Moreover, since the polymerization temperature at the time of performing radical polymerization can be suitably set according to the decomposition temperature of the polymerization initiator and the control of the reaction is easy, it is generally performed in the range of 30 to 150 ° C. It is preferable.

  The copolymer of the present invention can be used as an optical film comprising the copolymer.

  When the copolymer of the present invention is used as an optical film, the light transmittance is preferably 80% or more, and more preferably 85% or more, since image quality characteristics are good.

  When the copolymer of the present invention is used as an optical film, since the image quality is good, the haze (cloudiness) of the film is preferably 2% or less, and more preferably 1% or less. preferable.

  When the copolymer of the present invention is used as an optical film, it is preferable to use a retardation film because it has excellent retardation characteristics.

  In general, when used as a retardation film for a liquid crystal display or the like, it is required that the retardation characteristics do not change over a long period of time. The retardation film using the copolymer of the present invention is characterized in that the retardation characteristics do not change over a long period of time. That is, since it is excellent in retardation stability and can maintain high image quality, it can be suitably used as a retardation film for liquid crystal displays and the like.

  Since the retardation film using the copolymer of the present invention exhibits retardation even when unstretched, the refractive index in the fast axis direction in the film plane is nx, and the refractive index in the film in-plane direction perpendicular thereto is set. It is preferably used as a retardation film in which ny is a relationship of nx≈ny <nz when the refractive index in the thickness direction of the film is nz.

  As the retardation film using the copolymer of the present invention, only the copolymer can be used, or a composition mixed with another polymer can be used. At this time, the other polymer to be mixed may be a polymer having negative birefringence or a polymer having positive birefringence.

  When the copolymer of the present invention is used as a retardation film having negative birefringence, the film thickness can be reduced, so that the film thickness and the out-of-plane measured at a wavelength of 550 nm represented by the following formula (a) The ratio of the absolute value of the retardation (Rth) to the film thickness is preferably 6.5 nm / film thickness (μm) or more, more preferably 8 nm / film thickness (μm) or more, and 10 nm / film thickness (μm). The above is particularly preferable.

Rth = ((nx + ny) / 2−nz) × d (a)
(Here, d indicates the thickness of the film.)
There is no restriction | limiting in particular as a manufacturing method of the optical film of this invention, For example, methods, such as a solution cast method and a melt cast method, are mentioned.

  The solution casting method is a method in which a solution obtained by dissolving a copolymer in a solvent (hereinafter referred to as a dope) is cast on a support substrate, and then the solvent is removed by heating or the like to obtain a film. In this case, as a method for casting the dope on the support substrate, for example, a T-die method, a spin coater method, a doctor blade method, a bar coater method, a roll coater method, a lip coater method or the like is used. Particularly, industrially, a method in which a dope is continuously extruded from a die onto a belt-like or drum-like support substrate is the most common. Examples of the support substrate used include a glass substrate, a metal substrate such as stainless steel and ferrotype, and a film such as polyethylene terephthalate. In the solution casting method, when forming a film having high transparency and excellent thickness accuracy and surface smoothness, the solution viscosity of the dope is an extremely important factor, preferably 10 to 20,000 cPs. 100 to 10,000 cPs is more preferable.

  In this case, the coating thickness of the copolymer is preferably 1 to 200 μm, more preferably 2 to 100 μm, and particularly preferably 3 to 50 μm after drying because the film can be easily handled.

  The melt casting method is a molding method in which a copolymer is melted in an extruder and extruded from a slit of a T die into a film shape and then cooled and cooled with a roll or air.

  The retardation film using the copolymer of the present invention can be peeled off from the base glass substrate and other optical films and used as a laminate with the base glass substrate and other optical films. Can also be used. Moreover, the retardation film using the copolymer of the present invention may be stretched after film formation.

  The retardation film using the copolymer of the present invention can be laminated with a polarizing plate and used as a circular or elliptical polarizing plate, and laminated with a polarizer containing polyvinyl alcohol / iodine or the like to form a polarizing plate. It is also possible. Furthermore, it can also laminate | stack with retardation films using the copolymer of this invention, or other retardation films.

  In the retardation film using the copolymer of the present invention, an antioxidant is preferably blended in order to increase the thermal stability of the retardation film itself or during film formation. Examples of the antioxidant include hindered phenolic antioxidants, phosphorus antioxidants, and other antioxidants, and these antioxidants may be used alone or in combination. And since an antioxidant effect | action improves synergistically, it is preferable to use together a hindered antioxidant and phosphorus antioxidant, and in that case, for example with respect to 100 weight part of hindered antioxidant More preferably, the phosphorus-based antioxidant is used in a mixture of 100 to 500 parts by weight. In addition, the addition amount of the antioxidant is 0.01 to 10 parts by weight because it has an excellent antioxidant effect with respect to 100 parts by weight of the copolymer constituting the retardation film using the copolymer of the present invention. Is preferably 0.5 to 1 part by weight.

  Moreover, as an ultraviolet absorber, you may mix | blend ultraviolet absorbers, such as benzotriazole, a benzophenone, a triazine, a benzoate, as needed.

  The retardation film using the copolymer of the present invention is within the range not exceeding the gist of the invention, other polymers, surfactants, polymer electrolytes, conductive complexes, inorganic fillers, pigments, antistatic agents, antiblocking. You may mix | blend an agent, a lubricant, etc.

  The copolymer of the present invention is an optical film having a large refractive index in the thickness direction of a film useful for a compensation film for contrast and viewing angle characteristics of a liquid crystal display, a retardation film for a circularly polarizing plate of an organic EL display or an antireflection film. It is suitable for a retardation film having excellent characteristics.

  The copolymer of the present invention can be suitably used as a resin composition containing a resin having a positive intrinsic birefringence and an optical compensation film using the resin composition.

  In the present invention, the resin having positive intrinsic birefringence is not particularly limited as long as an optical compensation film having excellent retardation characteristics can be obtained using the resin. For example, cellulose resin, polycarbonate, cyclic polyolefin, polyethylene , Polypropylene, polyester, polyimide, polyamide, polyurethane and the like, and a cellulose-based resin is preferable because an optical compensation film having more excellent retardation characteristics can be obtained.

  In the present invention, when a cellulosic resin is used as a resin having positive intrinsic birefringence, when it is used as an optical compensation film, it is excellent in retardation characteristics and transparency, has a large in-plane retardation Re, and has a stretch processability. Therefore, it is preferably a cellulose resin represented by the following general formula (7).

(Wherein R _{23 to} R ₂₅ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, or acyl. Group (—C (═O) X ₃₃ ) (where X ₃₃ is a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms) ).)
Here, the cellulose resin represented by the general formula (7) is a polymer in which β-glucose units are linearly polymerized, and some or all of the hydroxyl groups at the 2nd, 3rd and 6th positions of the glucose unit. Is a polymer substituted.

Examples of the linear alkyl group having 1 to 12 carbon atoms in R _{23 to} R ₂₅ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the branched alkyl group having 1 to 12 carbon atoms include isopropyl group, sec-butyl group, tert-butyl group, isobutyl group and the like, and examples of the cyclic group having 3 to 14 carbon atoms include: A cyclopropyl group, a cyclobutyl group, a cyclohexyl group, a phenyl group, a naphthyl group, etc. are mentioned.

Examples of the linear alkyl group having 1 to 12 carbon atoms in X _33, for example, a methyl group, an ethyl group, n- propyl group, n- butyl group, n- pentyl group, n- hexyl, and the like, carbon Examples of the branched alkyl group having 1 to 12 include isopropyl group, sec-butyl group, tert-butyl group, isobutyl group and the like, and examples of the cyclic group having 3 to 14 carbon atoms include cyclopropyl group. , Cyclobutyl group, cyclohexyl group, phenyl group, naphthyl group and the like.

Examples of R _{23 to} R ₂₅ in the general formula (7) of the present invention include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isopropyl group, a sec-butyl group, a tert-butyl group, and an isobutyl group. , Cyclopropyl group, cyclobutyl group, cyclohexyl group, phenyl group, naphthyl group, acetyl group, propionyl group, butyryl group, pentanoyl group, hexanoyl group, heptanoyl group, isobutyryl group, tert-butyryl group, cyclohexanoyl group, benzoyl group And a naphthoyl group. Among these, a methyl group, an ethyl group, a propyl group, an acetyl group, a propionyl group, and a butyryl group are preferable because solubility and compatibility are further improved.

  The substitution degree of substitution through the oxygen atom of the hydroxyl group of cellulose in the cellulose resin of the present invention is the ratio of substitution of the hydroxyl group of cellulose for each of the 2-position, 3-position and 6-position (100% substitution) Means the degree of substitution 3), and the degree of substitution is preferably 1.5 to 3.0, more preferably 1.8 to 2.8 from the viewpoint of solubility, compatibility and stretch processability. .

  Specific examples of the cellulose resin of the present invention include methyl cellulose, ethyl cellulose, triacetyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and the like. Since a compensation film is obtained, ethyl cellulose, cellulose acetate butyrate, and cellulose acetate propionate are preferable.

  Since the cellulose resin of the present invention has excellent mechanical properties and excellent moldability during film formation, standard polystyrene obtained from an elution curve measured by gel permeation chromatography (GPC). The converted number average molecular weight (Mn) is preferably 1,000 to 1,000,000, and more preferably 5,000 to 200,000.

  The resin composition of the present invention is obtained by blending the copolymer of the present invention and a resin having positive intrinsic birefringence, and when used as an optical compensation film, the optical compensation film has a target position. It is characterized by exhibiting phase difference characteristics. That is, the copolymer of the present invention exhibits negative birefringence, and the copolymer of the present invention and a resin having positive intrinsic birefringence exhibit excellent compatibility. When the resin composition according to the present invention is used, an optical compensation film having practical transparency and excellent retardation characteristics can be obtained.

  Since the proportion of the composition of the copolymer of the present invention and the resin having positive intrinsic birefringence in the resin composition of the present invention is suitable for controlling the retardation when used as an optical compensation film, the copolymer of the present invention It is preferably 1 to 90% by weight and 99 to 10% by weight of a resin having positive intrinsic birefringence. More preferred is 10 to 85% by weight of the copolymer of the present invention and 90 to 15% by weight of a resin having positive intrinsic birefringence, and particularly preferred is 20 to 80% by weight of the copolymer of the present invention and positive intrinsic birefringence. The resin having refraction is 80 to 20% by weight.

  As a blending method, methods such as melt blending and solution blending can be used. The melt blending method is a method of manufacturing by melting and kneading a resin by heating. The solution blending method is a method in which a resin is dissolved in a solvent and blended. Solvents used for solution blending include, for example, chlorinated solvents such as methylene chloride and chloroform; aromatic solvents such as toluene and xylene; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone; ethyl acetate, An ester solvent such as butyl acetate; an alcohol solvent such as methanol, ethanol, or propanol; an ether solvent such as dioxane or tetrahydrofuran; dimethylformamide, N-methylpyrrolidone, or the like can be used. Each resin and additive can be dissolved in a solvent and then blended. The powder, pellets, etc. of each resin can be kneaded and then dissolved in the solvent.

  The resin composition of the present invention may contain an antioxidant in order to improve the thermal stability when making an optical compensation film. Antioxidants include, for example, hindered phenol antioxidants, phosphorus antioxidants, sulfur antioxidants, lactone antioxidants, amine antioxidants, hydroxylamine antioxidants, vitamin E series An antioxidant, other antioxidants, etc. are mentioned, and these antioxidants may be used alone or in combination of two or more.

  The resin composition of the present invention may contain a hindered amine light stabilizer or an ultraviolet absorber in order to enhance the weather resistance when making an optical compensation film. Examples of the ultraviolet absorber include benzotriazole, benzophenone, triazine, benzoate and the like.

  The resin composition of the present invention is an object for improving mechanical properties, imparting flexibility, imparting water absorption resistance, reducing water vapor permeability, adjusting retardation, etc., when a compound known as a plasticizer is used as an optical compensation film. The plasticizer may be, for example, a phosphate ester or a carboxylic acid ester. Acrylic polymers are also used.

  Examples of phosphate esters include triphenyl phosphate, tricresyl phosphate, phenyl diphenyl phosphate, and the like.

  Examples of the carboxylic acid ester include phthalic acid ester, citric acid ester, fatty acid ester, glycerol ester, and alkylphthalyl alkyl glycolate. Examples of the phthalate ester include dimethyl phthalate, diethyl phthalate, dicyclohexyl phthalate, dioctyl phthalate, and diethyl hexyl phthalate. Examples of the citrate ester include acetyl triethyl citrate and acetyl tributyl citrate. . Examples of the fatty acid ester include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and the like, and examples of the glycerol ester include triacetin, trimethylolpropane tribenzoate, and the like. Examples of the rate include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl glycolate, ethyl phthalate Methyl methacrylate, ethyl phthalyl propyl glycolate, propyl phthalyl ethyl glycolate, methyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl Phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalate Examples include rumethyl glycolate and octyl phthalyl ethyl glycolate. These plasticizers may be used alone or in combination of two or more.

  The resin composition of the present invention may contain an additive having an aromatic hydrocarbon ring or an aromatic heterocycle for the purpose of adjusting the phase difference in forming an optical compensation film. The birefringence Δn represented by the following formula (A) of the additive used for the purpose of adjusting the phase difference is not particularly limited, but is preferably 0 because it becomes an optical compensation film with more excellent optical characteristics. 0.05 or more, more preferably 0.05 to 0.5, and particularly preferably 0.1 to 0.5. The Δn of the additive can be obtained by molecular orbital calculation.

Δn = nx−ny (A)
(In the formula, nx represents the refractive index in the slow axis direction of the additive molecule, and ny represents the refractive index in the fast axis direction of the additive molecule.)
When an additive having an aromatic hydrocarbon ring or aromatic heterocycle is contained in the resin composition of the present invention, the number of the aromatic hydrocarbon ring or aromatic heterocycle in the molecule in the additive Although there is no restriction | limiting in particular, Since it becomes an optical compensation film excellent in the optical characteristic, Preferably it is 1-12 pieces, More preferably, it is 1-8 pieces. Examples of the aromatic hydrocarbon ring include a 5-membered ring, a 6-membered ring, a 7-membered ring, or a condensed ring composed of two or more aromatic rings. Examples of the aromatic heterocycle include a furan ring. Thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring, 1,3,5-triazine ring and the like.

  The aromatic hydrocarbon ring or aromatic heterocycle may have a substituent. Examples of the substituent include a hydroxyl group, an ether group, a carbonyl group, an ester group, a carboxylic acid residue, an amino group, and an imino group. Amide group, imide group, cyano group, nitro group, sulfonyl group, sulfonic acid residue, phosphonyl group, phosphonic acid residue and the like.

  Examples of the additive having an aromatic hydrocarbon ring or aromatic heterocycle used in the present invention include tricresyl phosphate, trixylenyl phosphate, triphenyl phosphate, 2-ethylhexyl diphenyl phosphate, cresyl diphenyl phosphate, Phosphate ester compounds such as bisphenol A bis (diphenyl phosphate); dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dinormal octyl phthalate, 2-ethylhexyl phthalate, diisooctyl phthalate, dicapryl phthalate, dinonyl phthalate, diisononyl Phthalate compounds such as phthalate, didecyl phthalate, diisodecyl phthalate; tributyl trimellitate, tri-normal hex Trimellitic acid ester-based compounds such as rutrimellitate, tri (2-ethylhexyl) trimellitate, tri-normal octyl trimellitate, tri-isoctyl trimellitate, tri-isodecyl trimellitate; tri (2-ethylhexyl) pyromellitate, Pyromellitic acid such as tetrabutyl pyromellitate, tetra-normal hexyl pyromellitate, tetra (2-ethylhexyl) pyromellitate, tetra-normal octyl pyromellitate, tetra-isooctyl pyromellitate, tetra-isodecyl pyromellitate Ester compounds; benzoic acid ester compounds such as ethyl benzoate, isopropyl benzoate, ethyl paraoxybenzoate; phenyl salicylate, p-octylphenyl salicylate, p-tert-butylphenol Salicylic acid ester compounds such as rusalicylate; Glycolic acid ester compounds such as methylphthalylethyl glycolate, ethylphthalylethyl glycolate, butylphthalylbutyl glycolate; 2- (2′-hydroxy-5′-t- Benzotriazole compounds such as butylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole; 2-hydroxy-4-methoxybenzophenone, 2,2′- Benzophenone compounds such as dihydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, N-benzenesulfone Sulfons such as amides Mido compounds, 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-ethoxyphenyl)- 1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-butoxyphenyl)- Triazine compounds such as 1,3,5-triazine and the like are mentioned, and since an optical compensation film having more excellent retardation characteristics can be obtained, tricresyl phosphate, 2-ethylhexyl diphenyl phosphate, 2-hydroxy-4-methoxy Benzophenone and 2,2 ′, 4,4′-tetrahydroxybenzophenone are preferred, and these may be one or more as required. It can be used in combination.

  When the resin composition of the present invention contains an additive having an aromatic hydrocarbon ring or an aromatic heterocycle, it is preferably an aromatic hydrocarbon ring or an aromatic heterocycle from the viewpoint of optical properties and mechanical properties. The ratio of the additive having a ring is 0.01 to 30% by weight, more preferably 0.01 to 20% by weight, and particularly preferably 0.01 to 15% by weight.

  The resin composition of the present invention contains other polymers, surfactants, polymer electrolytes, conductive complexes, pigments, dyes, antistatic agents, antiblocking agents, lubricants and the like within the scope of the invention. May be.

  The thickness of the optical compensation film of the present invention is preferably from 5 to 200 μm, more preferably from 5 to 150 μm, particularly preferably from 5 to 120 μm, from the viewpoints of handleability of the film and suitability for thinning of the optical member. .

  Since the optical compensation film of the present invention has good image quality characteristics, the light transmittance is preferably 80% or more, and more preferably 85% or more.

  Since the optical compensation film of the present invention has good image quality characteristics, the haze (cloudiness) of the film is preferably 2% or less, and more preferably 1% or less.

  The retardation property of the optical compensation film of the present invention is preferably such that the in-plane retardation (Re) represented by the following formula (b) is 50 to 500 nm, more preferably 100 to 450 nm, and particularly preferably 100 to 400 nm. The Nz coefficient represented by the following formula (c) is preferably 0 ≦ Nz ≦ 1.1, more preferably 0.30 ≦ Nz ≦ 0.65, and particularly preferably 0.35 ≦ Nz ≦ 0.60 Is preferred. The phase difference characteristic at this time is measured using a fully automatic birefringence meter (manufactured by AXOMETRICS, trade name: AxoScan) under a measurement wavelength of 589 nm.

  These are retardation characteristics that are difficult to develop with conventional optical compensation films.

Re = (nx−ny) × d (b)
Nz = (nx-nz) / (nx-ny) (c)
(Where nx represents the refractive index in the direction of the stretching axis in the film plane, ny represents the refractive index in the direction perpendicular to the stretching axis in the film plane, and nz represents the refractive index outside the film plane (thickness direction). D indicates the film thickness.)
As the wavelength dispersion characteristic of the optical compensation film of the present invention, the ratio Re (450) / Re (550) of the retardation at 450 nm to the retardation at 550 nm is preferably 0.60 <Re (450) in order to suppress color misregistration. /Re(550)<1.10, more preferably 0.70 <Re (450) / Re (550) <1.02, and particularly preferably 0.75 <Re (450) / Re (550). ) <1.00.

  As a method for producing the optical compensation film of the present invention, any method may be used as long as the optical compensation film of the present invention can be produced. An optical film excellent in optical properties, heat resistance, surface properties, and the like can be obtained. Therefore, it is preferable to manufacture by a solution casting method. Here, the solution casting method is a method of obtaining an optical film by casting a resin solution (generally referred to as a dope) on a support substrate and then evaporating the solvent by heating. As a casting method, for example, a T-die method, a doctor blade method, a bar coater method, a roll coater method, a lip coater method or the like is used. In general, a method of continuously extruding is used. Examples of the support substrate used include a glass substrate, a metal substrate such as stainless steel and ferrotype, and a plastic substrate such as polyethylene terephthalate. In order to industrially continuously form a substrate having high surface properties and optical homogeneity, a metal substrate having a mirror-finished surface is preferably used. In the solution casting method, the viscosity of the resin solution is an extremely important factor when producing an optical compensation film with excellent thickness accuracy and surface smoothness. The viscosity of the resin solution is the resin concentration, molecular weight, and type of solvent. It depends on.

  The viscosity of the resin solution when producing the optical compensation film of the present invention can be adjusted by the molecular weight of the polymer, the concentration of the polymer, and the type of solvent. The viscosity of the resin solution is not particularly limited, but is preferably 100 to 10000 cps, more preferably 300 to 5000 cps, and particularly preferably 500 to 3000 cps in order to make film coating easier.

  Examples of the method for producing the optical compensation film of the present invention include a residue unit A represented by the general formula (1), a residue unit B represented by the general formula (2), and a residue represented by the general formula (3). A resin composition containing a resin having unit C and a resin having positive intrinsic birefringence is dissolved in a solvent, and the resulting resin solution is cast on a substrate, dried, and then peeled off from the substrate. .

  In the present invention, the out-of-plane retardation (Rth) can be controlled by the concentration of the resin contained in the resin composition, the molecular weight of the resin, the type of solvent, and the film-forming drying temperature.

  The optical compensation film of the present invention is preferably uniaxially stretched or unbalanced biaxially stretched to develop in-plane retardation (Re). As a method for stretching the optical compensation film, it is possible to use a longitudinal uniaxial stretching method by roll stretching, a transverse uniaxial stretching method by tenter stretching, an unbalanced sequential biaxial stretching method or an unbalanced simultaneous biaxial stretching method by a combination thereof. it can. Moreover, in this invention, a phase difference characteristic can be expressed, without using the special extending | stretching method which extends | stretches under the effect | action of the shrinkage force of a heat-shrinkable film.

  The thickness of the film at the time of stretching is preferably from 10 to 200 μm, more preferably from 30 to 150 μm, particularly preferably from 30 to 120 μm, from the viewpoint of ease of stretching treatment and suitability for thinning of the optical member.

  The stretching temperature is not particularly limited, but is preferably 50 to 200 ° C., more preferably 100 to 180 ° C., because good retardation characteristics can be obtained. The stretching ratio of uniaxial stretching is preferably 1.05 to 3.5 times, and more preferably 1.1 to 3.0 times because good retardation characteristics can be obtained. Since the stretch ratio of unbalanced biaxial stretching can provide good retardation characteristics, 1.05 to 3.5 times are preferable in the length direction, 1.1 to 3.0 times are more preferable, and the width direction 1.0 to 1.2 times is preferable, and 1.0 to 1.1 times is more preferable. The in-plane retardation (Re) can be controlled by the stretching temperature and the stretching ratio.

  The optical compensation film of the present invention can be laminated with a film containing another resin as necessary. Examples of other resins include polyether sulfone, polyarylate, polyethylene terephthalate, polynaphthalene terephthalate, polycarbonate, cyclic polyolefin, maleimide resin, fluorine resin, polyimide, and the like. It is also possible to laminate a hard coat layer or a gas barrier layer.

  The copolymer of the present invention is a copolymer suitable for an optical film having excellent retardation characteristics, and is particularly suitable for an optical compensation film for liquid crystal display elements and organic EL.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

  In addition, the various physical properties shown by an Example were measured with the following method.

<Composition of copolymer>
Using a nuclear magnetic resonance measuring apparatus (manufactured by JEOL, trade name JNM-ECZ400S / L1), it was obtained by proton nuclear magnetic resonance spectroscopy ( ¹ H-NMR) spectrum analysis. Moreover, what was difficult to obtain | require by < ¹ > H-NMR spectrum analysis was calculated | required by CHN elemental analysis.

<Measurement of number average molecular weight>
Using a gel permeation chromatography (GPC) apparatus (trade name HLC8320GPC (equipped with column GMHHR-H) manufactured by Tosoh Corporation) using tetrahydrofuran or N, N-dimethylformamide as a solvent at 40 ° C., standard It calculated | required as a polystyrene or a standard pullulan conversion value.

<Transparency evaluation method>
The total light transmittance and haze of the film were measured using a haze meter (trade name NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.).

<Measurement of refractive index>
An Abbe refractometer (manufactured by Atago) was used and measured according to JIS K 7142 (1981 version).

<Measurement of retardation and three-dimensional refractive index of film>
Measurement was performed using a fully automatic birefringence meter (trade name KOBRA-WPR, manufactured by Oji Scientific Instruments).

<Measurement of glass transition temperature>
It measured using the differential scanning calorimeter (The product made by SII, brand name DSC6220).

Example 1 (Synthesis of isobutyl α-cyano-4-hydroxycinnamate / 9-vinylcarbazole / methyl acrylate copolymer)
In a glass ampoule having a capacity of 50 mL, 2.84 g (0.0229 mol) of isobutyl α-cyano-4-hydroxycinnamate, 6.31 g (0.0327 mol) of 9-vinylcarbazole, 0.84 g of methyl acrylate (0. 0098 mol), 0.25-g (0.00044 mol) of 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, which is a polymerization initiator, and 10 g of tetrahydrofuran were added, and nitrogen substitution and depressurization were performed. After repeating the above, it was sealed under reduced pressure. The ampoule was placed in a constant temperature bath at 62 ° C. and kept for 48 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, and then vacuum-dried at 60 ° C. for 10 hours to obtain α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / methyl acrylate copolymer. The compound 9.1g was obtained (yield: 91%).

  The number average molecular weight of the obtained α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / methyl acrylate copolymer was 16,000 in terms of standard polystyrene.

Moreover, by ¹ H-NMR measurement, the copolymer composition was α-cyano-4-hydroxycinnamate isobutyl residue unit / 9-vinylcarbazole residue unit / methyl acrylate residue unit = 30/56/14 ( Mol%) (residue unit A / residue unit B = 0.54, residue unit A / C = 2.14).

  The glass transition temperature of the obtained α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / methyl acrylate copolymer was 220 ° C. or higher.

Example 2 (Synthesis of 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / methyl methacrylate copolymer)
In a glass ampule with a capacity of 50 mL, 2.02 g (0.0098 mol) of 2-hydroxybenzylidenemalononitrile, 5.68 g (0.0328 mol) of N-vinylphthalimide, 2.30 g (0.0230 mol) of methyl methacrylate, polymerization Add 2,0-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane (0.20 g, 0.00044 mol) and 10 g of tetrahydrofuran as initiators, and repeat nitrogen substitution and depressurization. After that, it was sealed under reduced pressure. The ampoule was placed in a constant temperature bath at 62 ° C. and kept for 48 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, and then vacuum-dried at 60 ° C. for 10 hours to obtain 7.2 g of 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / methyl methacrylate copolymer. Obtained (yield: 72%).

  The number average molecular weight of the obtained 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / methyl methacrylate copolymer was 14,000 in terms of standard polystyrene.

The copolymer composition was determined by ¹ H-NMR measurement to be 2-hydroxybenzylidenemalononitrile residue unit / N-vinylphthalimide residue unit / methyl methacrylate residue unit = 13/51/36 (mol%) (residual Group unit A / residue unit B = 0.25, residue unit A / residue unit C = 0.36).

  The glass transition temperature of the obtained 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / methyl methacrylate copolymer was 220 ° C. or higher.

Example 3 (Synthesis of methyl α-cyano-4-carboxycinnamate / N-vinylsuccinimide / 2-ethylhexyl acrylate copolymer)
Α-Cyano-4-carboxycinnamate methyl 6.29 g (0.0256 mol), N-vinylsuccinimide 3.41 g (0.0272 mol), 2-ethylhexyl acrylate 0.30 g (50 mL glass ampule) 0.0016 mol), 0.167 g (0.00036 mol) of 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, which is a polymerization initiator, and 10 g of tetrahydrofuran, and nitrogen substitution. After repeating the depressurization, it was sealed in a reduced pressure state. The ampoule was placed in a constant temperature bath at 62 ° C. and kept for 24 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, and then vacuum-dried at 60 ° C. for 10 hours to obtain methyl α-cyano-4-carboxycinnamate / N-vinylsuccinimide / 2-ethylhexyl acrylate. 3.8 g of copolymer was obtained (yield: 38%).

  The number average molecular weight of the obtained methyl α-cyano-4-carboxycinnamate / N-vinylsuccinimide / 2-ethylhexyl acrylate copolymer was 10,000 in terms of standard polystyrene.

Further, by ¹ H-NMR measurement, the copolymer composition was α-cyano-4-carboxycinnamate methyl residue unit / N-vinylsuccinimide residue unit / 2-ethylhexyl acrylate residue unit = 41/55 / 4 (mol%) (residue unit A / residue unit B = 0.75, residue unit A / residue unit C = 10.3).

  The glass transition temperature of the obtained methyl α-cyano-4-carboxycinnamate / N-vinylsuccinimide / 2-ethylhexyl acrylate copolymer was 220 ° C. or higher.

Example 4 (Synthesis of α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / isobutyl acrylate copolymer)
In a glass ampoule having a capacity of 50 mL, 1.94 g (0.0157 mol) of isobutyl α-cyano-4-hydroxycinnamate, 6.05 g (0.0313 mol) of 9-vinylcarbazole, 2.01 g of isobutyl acrylate (0. 0,157 mol), 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane 0.192 g (0.00042 mol) and 10 g of tetrahydrofuran as polymerization initiators, and nitrogen substitution and depressurization After repeating the above, it was sealed under reduced pressure. The ampoule was placed in a constant temperature bath at 62 ° C. and kept for 48 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, and then vacuum-dried at 60 ° C. for 10 hours to obtain α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / isobutyl acrylate copolymer. The compound 8.6g was obtained (yield: 86%).

  The number average molecular weight of the obtained α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / isobutyl acrylate copolymer was 14,000 in terms of standard polystyrene.

Further, the copolymer composition was determined by ¹ H-NMR measurement to be α-cyano-4-hydroxycinnamate isobutyl residue unit / 9-vinylcarbazole residue unit / isobutyl acrylate residue unit = 24/51/25 ( Mol%) (residue unit A / residue unit B = 0.47, residue unit A / residue unit C = 0.96).

  The glass transition temperature of the obtained α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / isobutyl acrylate copolymer was 190 ° C.

Example 5 (Synthesis of 4-hydroxybenzylidenemalonate diethyl / N-vinylphthalimide / propyl methacrylate copolymer)
In a glass ampoule with a capacity of 50 mL, diethyl 4-hydroxybenzylidenemalonate 2.32 g (0.0088 mol), N-vinylphthalimide 5.06 g (0.0292 mol), propyl methacrylate 2.62 g (0.0205 mol), After adding 0.179 g (0.00039 mol) of 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, which is a polymerization initiator, and 10 g of tetrahydrofuran, repeating nitrogen substitution and depressurization. Sealed under reduced pressure. The ampoule was placed in a constant temperature bath at 62 ° C. and held for 2 hours for radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, and then vacuum-dried at 60 ° C. for 10 hours to give 6.7 g of 4-hydroxybenzylidene malonate / N-vinylphthalimide / propyl methacrylate copolymer. (Yield: 67%) was obtained.

  The number average molecular weight of the obtained 4-hydroxybenzylidene malonate diethyl / N-vinylphthalimide / propyl methacrylate copolymer was 21,000 in terms of standard pullulan.

Moreover, by ¹ H-NMR measurement, the copolymer composition was 4-hydroxybenzylidene malonate diethyl residue unit / N-vinylphthalimide residue unit / propyl methacrylate residue unit = 12/48/40 (mol%) ( Residue unit A / residue unit B = 0.25, residue unit A / residue unit C = 0.30).

  The glass transition temperature of the obtained 4-hydroxybenzylidenemalonate diethyl / N-vinylphthalimide / propyl methacrylate copolymer was 220 ° C. or higher.

Synthesis Example 1 (Synthesis of cinnamonitrile / styrene copolymer)
In a glass ampoule having a capacity of 50 mL, 5.0 g (0.039 mol) of cinnamonitrile, 4.1 g (0.039 mol) of styrene and 2,5-dimethyl-2,5-di (2-ethyl) which is a polymerization initiator Hexanoylperoxy) hexane (0.28 g, 0.00065 mol) was added, and after nitrogen substitution and depressurization were repeated, the mixture was sealed under reduced pressure. The ampoule was placed in a constant temperature bath at 62 ° C. and kept for 48 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, and then vacuum dried at 60 ° C. for 10 hours to obtain 5.4 g of a cinnamonitrile / styrene copolymer (yield: 59%).

  The number average molecular weight of the obtained cinnamonitrile / styrene copolymer was 46,000 in terms of standard polystyrene.

Moreover, the copolymer composition is a cinnamonitrile residue unit / styrene residue unit = 27/73 (mol%) (residue unit A / residue unit B = 0.37) by ¹ H-NMR measurement. It was confirmed.

Synthesis Example 2 (Synthesis of ethyl α-cyanocinnamate / methyl acrylate copolymer)
A glass ampoule with a capacity of 50 mL was charged with 5.0 g (0.025 mol) of ethyl α-cyanocinnamate, 2.2 g (0.026 mol) of methyl acrylate and 2,5-dimethyl-2,5-polymerization initiator. Di (2-ethylhexanoylperoxy) hexane (0.18 g, 0.00042 mol) was added, and after nitrogen substitution and depressurization were repeated, the mixture was sealed under reduced pressure. The ampoule was placed in a constant temperature bath at 62 ° C. and kept for 48 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, and then vacuum dried at 60 ° C. for 10 hours to obtain 2.5 g of α-ethyl cyanocinnamate / methyl acrylate copolymer (yield). : 35%).

  The number average molecular weight of the obtained α-cyanoethyl cinnamate / methyl acrylate copolymer was 13,000 in terms of standard polystyrene.

Further, by ¹ H-NMR measurement, the copolymer composition was α-cyanocinnamate ethyl residue unit / methyl acrylate residue unit = 11/89 (mol%) (residue unit A / residue unit B = 0. .12).

Synthesis Example 3 (Synthesis of benzalmalononitrile / styrene copolymer)
A glass ampoule having a capacity of 50 mL was charged with 5.0 g (0.032 mol) of benzalmalononitrile, 3.3 g (0.032 mol) of styrene and 2,5-dimethyl-2,5-di (2- Ethylhexanoylperoxy) hexane (0.23 g, 0.00053 mol) was added, and after nitrogen substitution and depressurization were repeated, the mixture was sealed under reduced pressure. The ampoule was placed in a constant temperature bath at 62 ° C. and kept for 48 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, and then vacuum-dried at 60 ° C. for 10 hours to obtain 5.8 g of benzalmalononitrile / styrene copolymer (yield: 70%).

  The number average molecular weight of the obtained benzalmalononitrile / styrene copolymer was 93,000 in terms of standard polystyrene.

Further, by ¹ H-NMR measurement, the copolymer composition was benzalmalononitrile residue unit / styrene residue unit = 36/64 (mol%) (residue unit A / residue unit B = 0.56). I confirmed that there was.

Synthesis Example 4 (Synthesis of methyl methacrylate / 9-vinylcarbazole polymer)
In a glass ampule having a capacity of 50 mL, 3.4 g (0.034 mol) of methyl methacrylate, 6.6 g (0.034 mol) of 9-vinylcarbazole, 4.5 g of tetrahydrofuran, and 2,5-dimethyl-2 which is a polymerization initiator , 5-Di (2-ethylhexanoylperoxy) hexane (0.24 g, 0.00052 mol) was added, and after nitrogen substitution and depressurization were repeated, the mixture was sealed under reduced pressure. The ampoule was placed in a constant temperature bath at 62 ° C. and kept for 48 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 25 g of tetrahydrofuran. This polymer solution was dropped into 500 mL of methanol and precipitated, followed by vacuum drying at 60 ° C. for 10 hours to obtain 9.6 g of methyl methacrylate / 9-vinylcarbazole copolymer (yield: 96% ).

  The number average molecular weight of the obtained methyl methacrylate / 9-vinylcarbazole copolymer was 10,000 in terms of standard polystyrene.

The copolymer composition was determined by ¹ H-NMR measurement to be a methyl methacrylate residue unit / 9-vinylcarbazole residue unit = 52/48 (mol%) (residue unit A / residue unit B = 1.08. ) Confirmed.

  The resulting methyl methacrylate / 9-vinylcarbazole copolymer had a glass transition temperature of 148 ° C.

Example 6
The isobutyl α-cyano-4-hydroxycinnamate / 9-vinylcarbazole / methyl acrylate copolymer obtained in Example 1 was dissolved in cyclopentanone to give a 35% by weight resin solution, and a glass substrate was formed by a coater. Casting on top and drying at 100 ° C. for 60 minutes, a film using a 10.5 μm-thick α-cyano-4-hydroxycinnamate / 9-vinylcarbazole / methyl acrylate copolymer is obtained. It was.

  The obtained film had a total light transmittance of 88%, a haze of 0.3% and a refractive index of 1.621.

  The three-dimensional refractive index was nx = 1.6159, ny = 1.6159, nz = 1.6326, and the obtained film exhibited a large value of refractive index in the thickness direction of nx≈ny <nz. . Further, the out-of-plane retardation Rth was as negative as −175 nm. The ratio between the absolute value of the out-of-plane retardation and the film thickness was 16.7 nm / film thickness (μm).

  When the film was measured after one month, it was a film having excellent out-of-plane retardation and excellent stability.

Example 7
The 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / methyl methacrylate copolymer obtained in Example 2 was dissolved in cyclopentanone to form a 30% by weight resin solution, which was cast on a glass substrate by a coater. By drying at 100 ° C. for 60 minutes, a film using a 9.2 μm-thick 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / methyl methacrylate copolymer was obtained.

  The obtained film had a total light transmittance of 89%, a haze of 0.5%, and a refractive index of 1.584.

  The three-dimensional refractive index was nx = 1.5757, ny = 1.5757, and nz = 1.607, and the obtained film exhibited a large value of refractive index in the thickness direction of nx≈ny <nz. . Further, the out-of-plane phase difference Rth was as negative as −230 nm. The ratio between the absolute value of the out-of-plane retardation and the film thickness was 25.0 nm / film thickness (μm).

  When the film was measured after one month, it was a film having excellent out-of-plane retardation and excellent stability.

Example 8
The methyl α-cyano-4-carboxycinnamate / N-vinylsuccinimide / 2-ethylhexyl acrylate copolymer obtained in Example 3 was dissolved in cyclopentanone to obtain a 25% by weight resin solution. By casting on a glass substrate and drying at 130 ° C. for 10 minutes, a 11.4 μm thick α-cyano-4-carboxycinnamate / N-vinylsuccinimide / 2-ethylhexyl acrylate copolymer is used. Film was obtained.

  The obtained film had a total light transmittance of 90%, a haze of 0.4%, and a refractive index of 1.569.

  The three-dimensional refractive index is nx = 1.653, ny = 1.6533, nz = 1.5753, and the obtained film has a large refractive index in the thickness direction of nx≈ny <nz. . Further, the out-of-plane retardation Rth was as negative as −125 nm. The ratio between the absolute value of the out-of-plane retardation and the film thickness was 11.0 nm / film thickness (μm).

  When the film was measured after one month, it was a film having excellent out-of-plane retardation and excellent stability.

Example 9
The α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / isobutyl acrylate copolymer obtained in Example 4 was dissolved in ethyl acetate to give a 30% by weight resin solution, which was coated on a glass substrate by a coater. And a film using an α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / isobutyl acrylate copolymer having a thickness of 12.1 μm was obtained by drying at 100 ° C. for 10 minutes. .

  The obtained film had a total light transmittance of 88%, a haze of 0.6%, and a refractive index of 1.605.

  The three-dimensional refractive index is nx = 1.5997, ny = 1.5997, nz = 1.6161, and the obtained film has a large refractive index in the thickness direction of nx≈ny <nz. . Further, the out-of-plane retardation Rth was as negative as -198 nm. The ratio between the absolute value of the out-of-plane retardation and the film thickness was 16.4 nm / film thickness (μm).

  When the film was measured after one month, it was a film having excellent out-of-plane retardation and excellent stability.

Example 10
The 4-hydroxybenzylidenemalonate diethyl / N-vinylphthalimide / propyl methacrylate copolymer obtained in Example 5 was dissolved in butyl acetate to give a 20% by weight resin solution, which was cast on a glass substrate by a coater. By drying at 80 ° C. for 1 hour, a film using a 9.8 μm thick 4-hydroxybenzylidene malonate diethyl / N-vinylphthalimide / propyl methacrylate copolymer was obtained.

  The obtained film had a total light transmittance of 89%, a haze of 0.5%, and a refractive index of 1.569.

  The three-dimensional refractive index is nx = 1.5636, ny = 1.5636, nz = 1.5792, and the obtained film has a large refractive index in the thickness direction of nx≈ny <nz. . Further, the out-of-plane retardation Rth was as negative as −152 nm. The ratio between the absolute value of the out-of-plane retardation and the film thickness was 15.5 nm / film thickness (μm).

  When the film was measured after one month, it was a film having excellent out-of-plane retardation and excellent stability.

Example 11 (Production of Optical Compensation Film Using Resin Composition Containing α-Cyano-4-hydroxycinnamate Isobutyl / 9-Vinylcarbazole / Methyl Acrylate Copolymer)
2.0 g of α-cyano-4-hydroxycinnamate / 9-vinylcarbazole / methyl acrylate copolymer obtained in Example 1 and ethyl cellulose (made by Dow Chemical Co., Ltd.) as a resin having positive intrinsic birefringence ETHOCEL standard 100, molecular weight Mn = 55,000, molecular weight Mw = 176,000, Mw / Mn = 3.2, total substitution degree DS = 2.5) 8.0 g was toluene / ethyl acetate = 4 / After dissolving in 6 (weight ratio) solution to give a 15% by weight resin solution and pouring on a polyethylene terephthalate film with a coater and drying in two stages at a drying temperature of 40 ° C. and 155 ° C., a film with a width of 150 mm is obtained. (Ethylcellulose: 80% by weight, isobutyl α-cyano-4-hydroxycinnamate / 9-vinylcarbazo And methyl acrylate copolymer: 20% by weight). The obtained film was cut into a 50 mm square and uniaxially stretched 1.5 times at 155 ° C. (thickness after stretching: 40 μm).

  The total optical transmittance, haze, retardation characteristics, and wavelength dispersion characteristics of the obtained optical compensation film were measured. The results are shown in Table 1.

  The obtained optical compensation film has high light transmittance, excellent transparency, small haze, in-plane retardation (Re), wavelength dispersion characteristics (Re (450) / Re (550)), and Nz coefficient. It has the optical characteristic to do.

Example 12 (Preparation of optical compensation film using resin composition containing 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / methyl methacrylate copolymer)
2.0 g of 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / methyl methacrylate copolymer obtained in Example 2 and ethyl cellulose (ETHOCEL standard manufactured by Dow Chemical Co., Ltd.) as a resin having positive intrinsic birefringence ) 100, molecular weight Mn = 55,000, molecular weight Mw = 176,000, Mw / Mn = 3.2, total substitution degree DS = 2.5) 10 g in toluene / ethyl acetate = 4/6 (weight ratio) solution A 15% by weight resin solution was dissolved and poured onto a polyethylene terephthalate film with a coater. After drying at a drying temperature of 40 ° C. and two stages at 160 ° C., a film having a width of 150 mm was obtained (ethyl cellulose: 83% by weight) 2-hydroxybenzylidenemalononitrile / N-vinylphthalimide / Methacrylic acid methyl copolymer: 17 wt%). The obtained film was cut into 50 mm squares and uniaxially stretched 1.8 times at 145 ° C. (thickness after stretching 60 μm).

  The total optical transmittance, haze, retardation characteristics, and wavelength dispersion characteristics of the obtained optical compensation film were measured. The results are also shown in Table 1.

  The obtained optical compensation film has high light transmittance, excellent transparency, small haze, in-plane retardation (Re), wavelength dispersion characteristics (Re (450) / Re (550)), and Nz coefficient. It has the optical characteristic to do.

Example 13 (Preparation of optical compensation film using resin composition containing methyl α-cyano-4-carboxycinnamate / N-vinylsuccinimide / 2-ethylhexyl acrylate copolymer)
3.5 g of α-cyano-4-carboxycinnamate methyl / N-vinylsuccinimide / 2-ethylhexyl acrylate copolymer obtained in Example 3 and cellulose acetate propionate as a resin having positive intrinsic birefringence (Molecular weight Mn = 75,000, acetyl group = 5 mol%, propionyl group = 80 mol%, total substitution degree DS = 2.55) 10 g was dissolved in a toluene / methyl ethyl ketone = 6/4 (weight ratio) solution to obtain 15 It was made into a weight% resin solution, poured onto a polyethylene terephthalate film with a coater, and dried in two stages at a drying temperature of 40 ° C. and then at 150 ° C. to obtain a film having a width of 150 mm (ethyl cellulose: 74% by weight, α-cyano -4-Carboxycinnamate methyl / N-vinylsuccinimide / 2-ethylhexyl acrylate copolymer: 2 6% by weight). The obtained film was cut into a 50 mm square and uniaxially stretched 1.7 times at 140 ° C. (thickness after stretching 55 μm).

  The total optical transmittance, haze, retardation characteristics, and wavelength dispersion characteristics of the obtained optical compensation film were measured. The results are also shown in Table 1.

  The obtained optical compensation film has high light transmittance, excellent transparency, small haze, in-plane retardation (Re), wavelength dispersion characteristics (Re (450) / Re (550)), and Nz coefficient. It has the optical characteristic to do.

Example 14 (Production of optical compensation film using resin composition containing α-cyano-4-hydroxycinnamate isobutyl / 9-vinylcarbazole / isobutyl acrylate copolymer)
2.5 g of α-cyano-4-hydroxycinnamate / 9-vinylcarbazole / isobutyl acrylate copolymer obtained in Example 4 and ethyl cellulose (made by Dow Chemical Company) as a resin having positive intrinsic birefringence ETHOCEL standard 100, molecular weight Mn = 55,000, molecular weight Mw = 176,000, Mw / Mn = 3.2, total substitution degree DS = 2.5) 7.5 g of toluene / ethyl acetate = 6 / After dissolving in a 4 (weight ratio) solution to give a 15% by weight resin solution, it was poured onto a polyethylene terephthalate film with a coater and dried in two stages at a drying temperature of 40 ° C. and 160 ° C. to obtain a film having a width of 150 mm. (Ethyl cellulose: 75% by weight, isobutyl α-cyano-4-hydroxycinnamate / 9-vinyl cal Vazole / isobutyl acrylate copolymer: 25% by weight). The obtained film was cut into 50 mm square and uniaxially stretched 2.0 times at 155 ° C. (thickness after stretching: 45 μm).

  The total optical transmittance, haze, retardation characteristics, and wavelength dispersion characteristics of the obtained optical compensation film were measured. The results are also shown in Table 1.

  The obtained optical compensation film has high light transmittance, excellent transparency, small haze, in-plane retardation (Re), wavelength dispersion characteristics (Re (450) / Re (550)), and Nz coefficient. It has the optical characteristic to do.

Example 15 (Production of optical compensation film using resin composition containing diethyl 4-hydroxybenzylidenemalonate / N-vinylphthalimide / propyl methacrylate copolymer)
2.0 g of 4-hydroxybenzylidenemalonate / N-vinylphthalimide / propyl methacrylate copolymer obtained in Example 5 and ethyl cellulose (ETHOCEL manufactured by Dow Chemical Co., Ltd.) as a resin having positive intrinsic birefringence standard) 100, molecular weight Mn = 55,000, molecular weight Mw = 176,000, Mw / Mn = 3.2, total substitution degree DS = 2.5) 10 g in toluene / ethyl acetate = 6/4 (weight ratio) solution A 15% by weight resin solution was dissolved into a polyethylene terephthalate film using a coater and dried in two stages at a drying temperature of 40 ° C. and 160 ° C. to obtain a film having a width of 150 mm (ethyl cellulose: 83% by weight). %, 4-hydroxybenzylidene malonate diethyl / N-vinylphthaly De / propyl methacrylate copolymer: 17 wt%). The obtained film was cut into 50 mm squares and uniaxially stretched 1.7 times at 150 ° C. (thickness after stretching 55 μm).

  The total optical transmittance, haze, retardation characteristics, and wavelength dispersion characteristics of the obtained optical compensation film were measured. The results are also shown in Table 1.

  The obtained optical compensation film has high light transmittance, excellent transparency, small haze, in-plane retardation (Re), wavelength dispersion characteristics (Re (450) / Re (550)), and Nz coefficient. It has the optical characteristic to do.

Comparative Example 1
The cinnamonitrile / styrene copolymer obtained in Synthesis Example 1 was dissolved in methyl ethyl ketone to form a 30% by weight resin solution, cast on a glass substrate with a coater, and dried at 60 ° C. for 60 minutes to obtain a thickness. A film of 12.5 μm was obtained.

  The obtained film had a total light transmittance of 88%, a haze of 0.5%, and a refractive index of 1.604.

  The three-dimensional refractive index is nx = 1.6021, ny = 1.6021, nz = 1.6605, and the obtained film has a large refractive index in the thickness direction of nx = ny <nz. However, the out-of-plane retardation Rth was as small as −55 nm, and the ratio between the absolute value of the out-of-plane retardation and the film thickness was as small as 4.4 nm / film thickness (μm).

  From these results, the obtained film had negative birefringence and a large refractive index in the thickness direction, but the out-of-plane retardation was small and the thin film was inferior in retardation characteristics.

Comparative Example 2
The α-cyanocyanocinnamate / methyl acrylate copolymer obtained in Synthesis Example 2 was dissolved in cyclopentanone to give a 30% by weight resin solution, which was cast on a glass substrate with a coater, and 10% at 100 ° C. A film having a thickness of 9.5 μm was obtained by partial drying.

  The obtained film had a total light transmittance of 88%, a haze of 0.3%, and a refractive index of 1.597.

  The three-dimensional refractive index is nx = 1.951, ny = 1.951, nz = 1.6001, and the obtained film has a large refractive index in the thickness direction of nx = ny <nz. However, the out-of-plane retardation Rth was as small as −48 nm, and the ratio between the absolute value of the out-of-plane retardation and the film thickness was as small as 5.0 nm / film thickness (μm).

  From these results, the obtained film had negative birefringence and a large refractive index in the thickness direction, but the out-of-plane retardation was small and the thin film was inferior in retardation characteristics.

Comparative Example 3
By dissolving the benzalmalononitrile / styrene copolymer obtained in Synthesis Example 3 in methyl ethyl ketone to form a 20% by weight resin solution, casting it on a glass substrate with a coater, and drying at 100 ° C. for 10 minutes, A film having a thickness of 9.1 μm was obtained.

  The obtained film had a total light transmittance of 88%, a haze of 0.5%, and a refractive index of 1.623.

  The three-dimensional refractive index is nx = 1.6213, ny = 1.6213, nz = 1.6270, and the obtained film has a large refractive index in the thickness direction of nx = ny <nz. However, the out-of-plane retardation Rth was as small as −52 nm, and the ratio between the absolute value of the out-of-plane retardation and the film thickness was as small as 5.7 nm / film thickness (μm).

  From these results, the obtained film had negative birefringence and a large refractive index in the thickness direction, but the out-of-plane retardation was small and the thin film was inferior in retardation characteristics.

Comparative Example 4
The methyl methacrylate / 9-vinylcarbazole polymer obtained in Synthesis Example 4 is dissolved in cyclopentanone to give a 30% by weight resin solution, cast on a glass substrate with a coater, and dried at 130 ° C. for 10 minutes. As a result, a film having a thickness of 10.3 μm was obtained.

  The obtained film had a total light transmittance of 90%, a haze of 0.4%, and a refractive index of 1.562.

  The three-dimensional refractive index is nx = 1.5610, ny = 1.5610, nz = 1.5651, and the obtained film has a small refractive index in the thickness direction of nx = ny <nz. The out-of-plane retardation Rth was as small as −43 nm, and the ratio between the absolute value of the out-of-plane retardation and the film thickness was as small as 4.2 nm / film thickness (μm).

  From these results, the obtained film had negative birefringence, the refractive index in the thickness direction was small, the out-of-plane retardation was small, and the retardation property was inferior in the thin film.

Comparative Example 5
Poly (9-vinylcarbazole) (number average molecular weight 264,000, manufactured by Tokyo Chemical Industry Co., Ltd.) is dissolved in cyclopentanone to form a 15% by weight resin solution, which is cast on a glass substrate with a coater, and at 100 ° C. for 10 minutes. By drying, a film using poly (9-vinylcarbazole) having a thickness of 13.2 μm was obtained.

  The obtained film had a total light transmittance of 87%, a haze of 0.6%, and a refractive index of 1.685.

  The three-dimensional refractive index is nx = 1.6785, ny = 1.6785, nz = 1.6990, and the obtained film has a large refractive index in the thickness direction of nx = ny <nz. . Further, the out-of-plane retardation Rth was as negative as −271 nm. The ratio between the absolute value of the out-of-plane retardation and the film thickness was 20.5 nm / film thickness (μm).

  From these results, the obtained film had a negative birefringence, a large refractive index in the thickness direction, a large negative out-of-plane retardation, and a high out-of-plane retardation even in a thin film. However, when the same film was measured again after 5 days, the three-dimensional refractive index was nx = 1.6849, ny = 1.68849, nz = 1.6866, and nx = ny <nz and the film thickness direction. The out-of-plane retardation Rth was −22 nm, and the ratio between the absolute value of the out-of-plane retardation and the film thickness was greatly reduced to 1.7 nm / film thickness (μm). In addition, because of the difficulty in stability, it was not suitable for a retardation film.

Comparative Example 6
2.0 g of cinnamonitrile / styrene copolymer obtained in Synthesis Example 1, ethyl cellulose (ETHOCEL standard 100 manufactured by Dow Chemical Co., Ltd.) as a resin having positive intrinsic birefringence, molecular weight Mn = 55,000, 10 g of molecular weight Mw = 176,000, Mw / Mn = 3.2, total substitution degree DS = 2.5) is dissolved in a toluene / ethyl acetate = 6/4 (weight ratio) solution to obtain a 15% by weight resin solution. The film was poured onto a polyethylene terephthalate film with a coater and dried in two stages at a drying temperature of 40 ° C. and then at 160 ° C. to obtain a film having a width of 150 mm (ethyl cellulose: 83% by weight, cinnamonitrile / styrene copolymer: 17% by weight).

  The obtained film had a light transmittance of 58% and a haze of 89%, was inferior in optical properties, and was not suitable for a retardation film.

Comparative Example 7
2.0 g of the α-cyanoethyl cinnamate / methyl acrylate copolymer obtained in Synthesis Example 2, ethyl cellulose (ETHOCEL standard 100 manufactured by Dow Chemical Co.) as the resin having positive intrinsic birefringence, molecular weight Mn = 55,000, molecular weight Mw = 176,000, Mw / Mn = 3.2, total substitution degree DS = 2.5) 10 g was dissolved in a toluene / ethyl acetate = 6/4 (weight ratio) solution to give 15 weight. % Resin solution was poured onto a polyethylene terephthalate film with a coater and dried in two stages at a drying temperature of 40 ° C. and then at 150 ° C. to obtain a film having a width of 150 mm (ethyl cellulose: 83% by weight, α-cyanosilicate skin Ethyl acetate / methyl acrylate copolymer: 17% by weight).

  The obtained film had a light transmittance of 36% and a haze of 72%, was inferior in optical properties, and was not suitable for a retardation film.

Comparative Example 8
2.0 g of benzalmalononitrile / styrene copolymer obtained in Synthesis Example 3, cellulose acetate propionate (molecular weight Mn = 75,000, acetyl group = 5 mol%, propionyl) as a resin having positive intrinsic birefringence Group = 80 mol%, total substitution degree DS = 2.55) 10 g was dissolved in a toluene / ethyl acetate = 6/4 (weight ratio) solution to form a 15 wt% resin solution, which was then poured onto a polyethylene terephthalate film by a coater. After drying at a drying temperature of 40 ° C. and two steps at 150 ° C., a film having a width of 150 mm was obtained (ethyl cellulose: 83 wt%, benzalmalononitrile / styrene copolymer: 17 wt%).

  The obtained film had a light transmittance of 62% and a haze of 91%, was inferior in optical properties, and was not suitable for a retardation film.

Comparative Example 9
2.0 g of the methyl methacrylate / 9-vinylcarbazole copolymer obtained in Synthesis Example 4, ethyl cellulose (ETHOCEL standard 100 manufactured by Dow Chemical Company) as a resin having positive intrinsic birefringence, molecular weight Mn = 55 , 1,000, molecular weight Mw = 176,000, Mw / Mn = 3.2, total substitution degree DS = 2.5) 10 g was dissolved in a toluene / ethyl acetate = 6/4 (weight ratio) solution to obtain 15 wt% A resin solution was poured onto a polyethylene terephthalate film with a coater and dried in two stages at a drying temperature of 40 ° C. and then at 150 ° C. to obtain a film having a width of 150 mm (ethyl cellulose: 83% by weight, methyl methacrylate / 9- Vinylcarbazole copolymer: 17% by weight).

  The obtained film had a light transmittance of 45% and a haze of 66%, inferior optical properties, and was not suitable for a retardation film.

Claims (11)

Residue unit A represented by general formula (1), residue unit B represented by general formula (2) and residue unit C represented by general formula (3) Coalescence.

(Here, R ₁ and R ₂ are each independently hydrogen (except when R ₁ and R ₂ are both hydrogen), a cyano group, an ester group (—C (═O) OX ₁ ), An amide group (—C (═O) N (X ₂ ) (X ₃ )), or an acyl group (—C (═O) X ₄ ) (where X _{1 to} X ₃ each independently represents 1 carbon atom) 12 linear alkyl group, branched alkyl group having 1 to 12 carbon atoms, or cyclic alkyl group having 3 to 6 carbon atoms, _{X 4} is a linear alkyl group having 1 to 12 carbon atoms, carbon atoms R _{3 to} R ₇ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, carbon, and a branched alkyl group having 1 to 12 carbon atoms or a cyclic group having ₃ to 14 carbon atoms. A branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, halogen, hydroxy group, carboxy group, nitro , A cyano group, an alkoxy group _(-OX 5), an ester group _{(-C (= O) OX 6} ), an amide group _{(-C (= O) N (} X 7) (X 8)), an acyl group (-C (═O) X ₉ ), an amino group (—N (X ₁₀ ) (X ₁₁ )), or a sulfonic acid group (—SOOX ₁₂ ) (where X _{5 to} X ₈ each independently represent 1 carbon atom) Represents a linear alkyl group having ˜12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, and X _{9 to} X ₁₂ are each independently hydrogen, 1 to 12 carbon atoms. A straight-chain alkyl group, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.), Wherein at least one of R _{3 to} R ₇ is a hydroxy group or a carboxy group It is shown. in addition, R ₃ to R ₇ may form a fused ring structure adjacent substituents It may be.)

(Here, R ₈ represents an m-membered heterocyclic residue containing one or more heteroatoms, or a 5-membered or 6-membered ring residue not containing a heteroatom (provided that R ₈ contains a heteroatom) In the case of no 6-membered ring residue, at least one of R _{3 to} R ₇ in the general formula (1) represents a hydroxy group.), M represents an integer of 5 to 10. The m-membered ring heterocyclic residue The group, the 5-membered ring residue, and the 6-membered ring residue may form a condensed ring structure.)

(Here, R ₉ and R ₁₀ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms. Show.) The copolymer according to claim 1, wherein R ₁ and R ₂ are each independently selected from the group consisting of a cyano group, an ester group, an amide group, and an acyl group. Residue unit A represented by general formula (1) and residue unit C represented by general formula (3) are further included, and residue unit B is further represented by general formula (4) and / or general formula (5). The copolymer according to claim 1, wherein the copolymer is a residue unit represented by the formula:

(Here, R _{11 to} R ₁₈ are each independently hydrogen, halogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, A cyano group, a nitro group, a hydroxy group, a carboxy group, a thiol group, an alkoxy group (—OX ₁₃ ), an ester group (—C (═O) OX ₁₄ or —CO (═O) —X ₁₅ ), an amide group (— C (═O) N (X ₁₆ ) (X ₁₇ ) or —NX ₁₈ C (═O) X ₁₉ ), acyl group (—C (═O) X ₂₀ ) or amino group (—N (X ₂₁ ) ( X ₂₂ )) (where X _{13 to} X ₁₅ are each independently a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms. X _{16 to} X ₂₂ each independently represent hydrogen or carbon number A linear alkyl group having 1 to 12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms.), And R _{11 to} R ₁₈ are adjacent to each other. And a condensed ring structure may be formed, and R ₁₁ and R ₁₁₇ and R ₁₂ and R ₁₈ may be the same atom to form a ring structure.)

(Here, R _{19 to} R ₂₂ are each independently hydrogen, halogen, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, Cyano group, nitro group, hydroxy group, carboxy group, thiol group, alkoxy group (—OX ₂₃ ), ester group (—C (═O) OX ₂₄ or —CO (═O) —X ₂₅ ), amide group (— C (═O) N (X ₂₆ ) (X ₂₇ ) or —NX ₂₈ C (═O) X ₂₉ ), acyl group (—C (═O) X ₃₀ ) or amino group (—N (X ₃₁ ) ( X ₃₂ )) (where X _{23 to} X ₂₅ are each independently a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms. X _{26 to} X ₃₂ each independently represent hydrogen or carbon number. A linear alkyl group having 1 to 12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic group having 3 to 14 carbon atoms.) And R _{19 to} R ₂₂ are adjacent to each other. And a condensed ring structure may be formed, and R ₁₉ and R ₂₀ and R ₂₁ and ₂₂ may be the same atom to form a ring structure.) The molar ratio A / B of the residue unit A represented by the general formula (1) and the residue unit B represented by the general formula (2) is in the range of 0.05 to 6, and the general formula (1) The molar ratio A / C of the residue unit A and the residue unit C represented by the general formula (3) is in the range of 0.02 to 50. The copolymer in any one. Standard polystyrene conversion when the residue unit B is a residue unit B other than the general formula (4) or standard pullulan conversion number when the residue unit B is a residue unit represented by the general formula (4) The copolymer according to any one of claims 1 to 4, wherein the average molecular weight is 3,000 to 500,000. The copolymer according to any one of claims 1 to 5, wherein the glass transition temperature is 150 ° C or higher. The method for producing a copolymer according to any one of claims 1 to 6, wherein polymerization is performed using a monomer represented by the general formula (6).

(Here, R ₁ and R ₂ are each independently hydrogen (except when R ₁ and R ₂ are both hydrogen), a cyano group, an ester group (—C (═O) OX ₁ ), An amide group (—C (═O) N (X ₂ ) (X ₃ )), or an acyl group (—C (═O) X ₄ ) (where X _{1 to} X ₃ each independently represents 1 carbon atom) 12 linear alkyl group, branched alkyl group having 1 to 12 carbon atoms, or cyclic alkyl group having 3 to 6 carbon atoms, _{X 4} is a linear alkyl group having 1 to 12 carbon atoms, carbon atoms R _{3 to} R ₇ are each independently hydrogen, a linear alkyl group having 1 to 12 carbon atoms, carbon, and a branched alkyl group having 1 to 12 carbon atoms or a cyclic group having ₃ to 14 carbon atoms. A branched alkyl group having 1 to 12 carbon atoms, a cyclic group having 3 to 14 carbon atoms, halogen, hydroxy group, carboxy group, nitro , A cyano group, an alkoxy group _(-OX 5), an ester group _{(-C (= O) OX 6} ), an amide group _{(-C (= O) N (} X 7) (X 8)), an acyl group (-C (═O) X ₉ ), an amino group (—N (X ₁₀ ) (X ₁₁ )), or a sulfonic acid group (—SOOX ₁₂ ) (where X _{5 to} X ₈ each independently represent 1 carbon atom) Represents a linear alkyl group having ˜12, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, and X _{9 to} X ₁₂ are each independently hydrogen, 1 to 12 carbon atoms. A straight-chain alkyl group, a branched alkyl group having 1 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.), Wherein at least one of R _{3 to} R ₇ is a hydroxy group or a carboxy group It is shown. in addition, R ₃ to R ₇ may form a fused ring structure adjacent substituents It may be.) An optical film comprising the copolymer according to any one of claims 1 to 6. The relationship when the refractive index in the fast axis direction in the film plane is nx, the refractive index in the film in-plane direction perpendicular thereto is ny, and the refractive index in the thickness direction of the film is nz is nx≈ny <nz. A retardation film using the optical film according to claim 8. A resin composition comprising the copolymer according to claim 1 and a resin having positive intrinsic birefringence. An in-plane retardation (Re) represented by the following formula (b) is 50 to 500 nm, and an Nz coefficient represented by the following formula (c) is 0 ≦ Nz ≦. 1.1, and the ratio Re (450) / Re (550) of the in-plane retardation (Re) at a light wavelength of 450 nm to the in-plane retardation (Re) at a light wavelength of 550 nm is 0.60 <Re An optical compensation film, wherein (450) / Re (550) <1.10.
Re = (nx−ny) × d (b)
Nz = (nx-nz) / (nx-ny) (c)
(Where nx represents the refractive index in the direction of the stretching axis in the film plane, ny represents the refractive index in the direction perpendicular to the stretching axis in the film plane, and nz represents the refractive index outside the film plane (thickness direction). D indicates the film thickness.)