JP6759617B2 - Resin composition - Google Patents

Description

The present invention relates to a novel resin composition and a retardation film using the same, and more specifically, a retardation film having a high out-of-plane retardation even in a thin film, particularly an optical compensation film for a liquid crystal display element. It relates to a novel resin composition suitable for the above.

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

Many optical films are used in liquid crystal displays to improve display characteristics, and in particular, retardation films play a major role in improving contrast when viewed from the front or at an angle, and compensating for color tones. Polycarbonate and cyclic polyolefin are used as the conventional retardation film, and all of these polymers are polymers having positive birefringence. Here, the positive and negative of birefringence are defined as shown below.

The optical anisotropy of the polymer film molecularly oriented by stretching or the like can be represented by the refractive index ellipsoid shown in FIG. Here, the refractive index in the phase-advancing axis direction in the film plane when the film is stretched is shown as nx, the refractive index in the in-plane direction of the film orthogonal to it is shown as ny, and the refractive index in the thickness direction of the film is shown as nz. The phase-advancing axis refers to the axial direction in which the refractive index is low in the film plane.

Negative birefringence means that the stretching direction is the phase-advancing axis direction, and positive birefringence means that the direction perpendicular to the stretching direction is the phase-advancing axis direction.

That is, in the uniaxial stretching of a polymer having negative birefringence, the refractive index in the stretching axis direction is small (phase-advancing axis: stretching direction), and in the uniaxial stretching of a polymer having positive birefringence, the axial direction orthogonal to the stretching axis. The refractive index of is small (phase advance axis: direction perpendicular to the stretching direction).

Many macromolecules have positive birefringence. Acrylic resin and polystyrene are examples of polymers having negative birefringence, but acrylic resin has a small retardation and its characteristics as a retardation film are not sufficient. Polystyrene is not currently used because it has a large photoelastic modulus in a low temperature region, so that the phase difference changes with a slight stress, and there is a problem of stability of the phase difference and a practical problem of low heat resistance. ..

A polymer stretched film showing negative birefringence has a high refractive index in the thickness direction of the film, resulting in an unprecedented retardation film. Therefore, for example, a super twist nematic liquid crystal display (STN-LCD) or a vertically oriented 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 the viewing angle characteristics and a viewing angle compensating film for a deflection plate. There is a strong market demand for retardation films with negative birefringence.

A method for producing a film in which the refractive index in the thickness direction of the film is increased by using a polymer having positive birefringence has been proposed. One is a treatment method in which a heat-shrinkable film is adhered to one or both sides of a polymer film, the laminate is heat-stretched, and a shrinkage force is applied in the film thickness direction of the polymer film (for example, Patent Documents 1 to 3). See). Further, a method of uniaxially stretching the polymer film while applying an electric field has been proposed (see, for example, Patent Document 4).

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

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

When polycarbonate is used as the base film, the photoelastic coefficient at room temperature is large and the phase difference changes due to a slight stress, so that there is a problem in the stability of the phase difference. Furthermore, there is a problem that the wavelength dependence of the phase difference is large.

The retardation film obtained in Patent Document 5 is a retardation film that exhibits negative birefringence by adding fine particles having negative optical anisotropy, and is fine particles from the viewpoint of simplification of manufacturing method and economy. There is a demand for a retardation film that does not require the addition of.

Further, a fumaric acid diester resin and a film made of the same have been proposed (see, for example, Patent Documents 6 to 10).

Further, a diisopropyl fumarate-cinnamic acid derivative based copolymer containing a diisopropyl fumarate residue unit and a cinnamic acid residue unit or a cinnamic acid ester residue unit having an alkyl group having 1 to 6 carbon atoms, and A retardation film using the diisopropyl fumarate-cinnamic acid derivative-based copolymer has been proposed (see, for example, Patent Document 11).

Further, a fumal containing a fumaric acid diester residue unit, a silicic acid ester residue unit having an alkyl group having 1 to 6 carbon atoms, and a residue unit of a polyfunctional monomer having two or more radically polymerizable functional groups. A retardation film using an acid diester-silicate ester-based copolymer and the fumaric acid diester-silicate ester-based copolymer has been proposed (see, for example, Patent Document 12).

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

Although the fumaric acid diester resin and the film made thereof proposed in Patent Documents 6 to 10 have a high out-of-plane retardation, at present, even a thin film has a higher out-of-plane retardation. It has been demanded.

The diisopropyl fumarate-cinnamic acid derivative-based copolymers proposed in Patent Documents 11 and 12 exhibit higher out-of-plane retardation than the resins proposed in Patent Documents 6 to 10, but even in thin films. There is a demand for a film having a high out-of-plane phase difference.

An object of the present invention is to provide a novel resin composition suitable for a retardation film having a high out-of-plane retardation even in a thin film and having excellent optical characteristics.

As a result of diligent studies to solve the above problems, the present inventors have found that a resin composition containing a specific compound and a polymer having a specific substituent can solve the above problems, and complete the present invention. It came to.

That is, the present invention relates to a resin composition and a retardation film containing at least a pyridine derivative represented by the general formula (1) and a polymer having a carboxyl group.

(Here, R _{1 to} R ₄ independently represent hydrogen or an arbitrary substituent, and Ar represents a substituted or unsubstituted aromatic group.)
Hereinafter, the resin composition suitable for the retardation film of the present invention will be described in detail.

The resin composition of the present invention is a resin composition containing at least a pyridine derivative represented by the general formula (1) and a polymer having a carboxyl group. Then, by containing a specific pyridine derivative and a polymer having a carboxyl group, a higher out-of-plane retardation is exhibited in a thinner film when used as a retardation film.

R _{1 to} R ₄ in the general formula (1) of the present invention independently represent hydrogen or an arbitrary substituent, and examples of the optional substituent include an alkyl group, a hydroxyl group, an alkoxyl group, a carboxyl group, and a cyano group. Examples include groups, nitro groups, phenyl groups and the like. In addition, Ar represents a substituted or unsubstituted aromatic group, for example, a phenyl group, a pentarenyl group, an indenyl group, a naphthalenyl group, an azulenyl group, a heptalenyl group, an indasenyl group, a biphenylenyl group, an acenaphthylenyl group, a fluorenyl group, a phenylenyl group, Phenantrenyl group, anthracenyl group, flanyl group, pyranyl group, benzofuranyl group, isobenzofuranyl group, chromenyl group, isochromenyl group, xanthenyl group, thienyl group, thiochromenyl group, isothioquomenyl group, thioxanthenyl group, thianthrenyl group, phenoxati Inyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyrazinyl group, pyrimidinyl group, pyridadinyl group, pyrrolidinyl group, pyrindinyl group, indridinyl group, indolyl group, isoindryl group, indazolyl group, prynyl group, quinolidinyl group, quinolyl Group, isoquinolyl group, naphthyldinyl group, carbazolyl group, carbolinyl group, phenanthridinyl group, acridinyl group, perimidinyl group, phenanthronyl group, phenazinyl group, phenothianidyl group, phenoxadinyl group, antilydinyl group, and substituted aromatics derived from these. The groups and the like can be exemplified. Of these, a phenyl group and a pyridyl group are preferable because they exhibit a particularly high phase difference.

Specific examples of the pyridine derivative represented by the general formula (1) of the present invention include 4-phenylpyridine, 4- (p-tolyl) pyridine, 4- (4-cyanophenylpyridine), and 4-nitrophenyl. Pyridine, 4- (4-methoxyphenylpyridine), 1-pentalenyl-4-pyridine, 2-pentalenyl-4-pyridine, 1-indenyl-4-pyridine, 2-indenyl-4-pyridine, 4-indenyl-4-pyridine Pyridine, 5-indenyl-4-pyridine, 1-naphthalenyl-4-pyridine, 2-naphthalenyl-4-pyridine, 1-azulenyl-4-pyridine, 2-azurenyl-4-pyridine, 4-azulenyl-4-pyridine, 5-Azrenyl-4-pyridine, 6-Azulenyl-4-pyridine, 1-heptalenyl-4-pyridine, 2-heptalenyl-4-pyridine, 3-heptalenyl-4-pyridine, 1-s-indacenyl-4-pyridine, 2-s-Indasenyl-4-pyridine, 4-s-Indasenyl-4-pyridine, 1-as-Indasenyl-4-pyridine, 2-as-Indasenyl-4-pyridine, 3-as-Indasenyl-4-pyridine, 4-as-indacenyl-4-pyridine, 1-biphenylenyl-4-pyridine, 2-biphenylenyl-4-pyridine, 1-acenaftyrenyl-4-pyridine, 3-acenaftyrenyl-4-pyridine, 4-acenaftyrenyl-4-pyridine, 5-Acenaftyrenyl-4-pyridine, 1-fluorenyl-4-pyridine, 2-fluorenyl-4-pyridine, 3-fluorenyl-4-pyridine, 4-fluorenyl-4-pyridine, 9-fluorenyl-4-pyridine, 1- Phenalenyl-4-pyridine, 2-phenalenyl-4-pyridine, 1-phenanthrenyl-4-pyridine, 2-phenanthrenyl-4-pyridine, 3-phenanthrenyl-4-pyridine, 4-phenanthrenyl-4-pyridine, 9-phenanthrenyl- 4-Pyridine, 1-anthrasenyl-4-pyridine, 2-anthrasenyl-4-pyridine, 9-anthrasenyl-4-pyridine, 2-furanyl-4-pyridine, 3-furanyl-4-pyridine, 2-pyranyl-4-pyridine Pyridine, 4-pyranyl-4-pyridine, 2-benzofuranyl-4-pyridine, 3-benzofuranyl-4-pyridine, 4-benzofuranyl-4-pyridine, 5-benzofuranyl-4-pyridine, 6-benzofuranyl-4-pyridine, 7-Benzoflanyl-4- Pyridine, 1-isobenzofuranyl-4-pyridine, 4-isobenzofuranyl-4-pyridine, 5-isobenzofuranyl-4-pyridine, 5-chromenyl-4-pyridine, 6-chromenyl-4-pyridine , 7-chromenyl-4-pyridine, 8-chromenyl-4-pyridine, 5-isochromenyl-4-pyridine, 6-isochromenyl-4-pyridine, 7-isochromenyl-4-pyridine, 8-isochromenyl-4-pyridine, 1 -Xanthenyl-4-pyridine, 2-xanthenyl-4-pyridine, 3-xanthenyl-4-pyridine, 4-xanthenyl-4-pyridine, 9-xanthenyl-4-pyridine, 2-thienyl-4-pyridine, 3-thienyl -4-Pyridine, 5-thiochromenyl-4-pyridine, 6-thiochromenyl-4-pyridine, 7-thiochromenyl-4-pyridine, 8-thiochromenyl-4-pyridine, 5-isothiochromenyl-4-pyridine, 6-isoti Ochromenyl-4-pyridine, 7-isothiochromenyl-4-pyridine, 8-isothiochromenyl-4-pyridine, 1-thioxanthenyl-4-pyridine, 2-thioxanthenyl-4-pyridine, 3-thioxanthenyl-4-pyridine , 4-Thioxanthenyl-4-pyridine, 9-thioxanthenyl-4-pyridine, 1-thianthrenyl-4-pyridine, 2-thianthrenyl-4-pyridine, 1-phenoxathinyl-4-pyridine, 2-phenoxatinyl -4-Pyridine, 3-Phenoxatiinyl-4-pyridine, 4-Phenoxatiinyl-4-pyridine, 1-Pyrrolyl-4-pyridine, 2-Pyrrolyl-4-pyridine, 3-Pyrrolyl-4-pyridine 1, 1-Imidazolyl-4-pyridine, 2-Imidazolyl-4-pyridine, 4-Imidazolyl-4-pyridine, 5-Imidazolyl-4-pyridine, 1-Pyrazolyl-4-pyridine, 3-Pyrazolyl-4-pyridine, 4 -Pyrazolyl-4-pyridine, 5-pyrazolyl-4-pyridine, 2-pyridyl-4-pyridine, 3-pyridyl-4-pyridine, 4,4'-bipyridine, 2-pyrazinyl-4-pyridine, 3-pyrazinyl- 4-Pyridine, 2-pyrimidinyl-4-pyridine, 4-pyrimidinyl-4-pyridine, 5-pyrimidinyl-4-pyridine, 3-pyridazinyl-4-pyridine, 4-pyridadinyl-4-pyridine, 4-pyridadinyl-4-pyridine Pyridine, 5-pyrrolidinyl-4-pyridine, 6-pyrrolidinyl-4- Pyridine, 7-pyrrolidinyl-4-pyridine, 1-pyringinyl-4-pyridine, 2-pyringinyl-4-pyridine, 3-pyringinyl-4-pyridine, 4-pyringinyl-4-pyridine, 5-pyringinyl-4-pyridine, 6-Pyringinyl-4-pyridine, 7-Pyringinyl-4-pyridine, 1-Indridinyl-4-pyridine, 2-Indridinyl-4-pyridine, 3-Indridinyl-4-pyridine, 5-Indridinyl-4-pyridine, 6- Indridinyl-4-pyridine, 7-Indridinyl-4-pyridine, 8-Indridinyl-4-pyridine, 1-Indrill-4-pyridine, 2-Indrill-4-pyridine, 3-Indrill-4-pyridine, 4-Indrill- 4-Pyridine, 5-Indrill-4-pyridine, 6-Indrill-4-pyridine, 7-Indrill-4-pyridine, 1-Isoindrill-4-pyridine, 2-Isoindrill-4-pyridine, 4-Isoindrill-4- Pyridine, 5-isoindrill-4-pyridine, 4-indazolyl-4-pyridine, 5-indazolyl-4-pyridine, 6-indazolyl-4-pyridine, 7-indazolyl-4-pyridine, 1-prinyl-4-pyridine, 2-Prinyl-4-pyridine, 3-Prinyl-4-pyridine, 6-Prinyl-4-pyridine, 7-Prinyl-4-pyridine, 8-Prinyl-4-pyridine, 1-quinolidinyl-4-pyridine, 2- Kinolidinyl-4-pyridine, 3-quinolidinyl-4-pyridine, 4-quinolidinyl-4-pyridine, 2-quinolyl-4-pyridine, 3-quinolyl-4-pyridine, 4-quinolyl-4-pyridine, 5-quinolyl- 4-Pyridine, 6-quinolyl-4-pyridine, 7-quinolyl-4-pyridine, 8-quinolyl-4-pyridine, 1-isoquinolyl-4-pyridine, 3-isoquinolyl-4-pyridine, 4-isoquinolyl-4-pyridine Pyridine, 5-isoquinolyl-4-pyridine, 6-isoquinolyl-4-pyridine, 7-isoquinolyl-4-pyridine, 8-isoquinolyl-4-pyridine, 1-naphthylidineyl-4-pyridine, 3-naphthylidineyl-4-pyridine, 4-naphthyridinyl-4-pyridine, 1-carbazolyl-4-pyridine, 2-carbazolyl-4-pyridine, 3-carbazolyl-4-pyridine, 4-carbazolyl-4-pyridine, 9-carbazolyl-4-pyridine, 1- Phenantridinyl-4-pyridine, 2-f Enantridinyl-4-pyridine, 3-phenanthridinyl-4-pyridine, 4-phenanthridinyl-4-pyridine, 6-phenanthridinyl-4-pyridine, 7-phenanthridinyl-4-pyridine, 8-Phenantridinyl-4-pyridine, 9-Phenantridinyl-4-pyridine, 10-Phenantridinyl-4-pyridine, 1-acridinyl-4-pyridine, 2-acridinyl-4-pyridine, 3 −Acridinyl-4-pyridine, 4-acridinyl-4-pyridine, 9-acridinyl-4-pyridine, 1-perimidinyl-4-pyridine, 2-perimidinyl-4-pyridine, 4-perimidinyl-4-pyridine, 5-perimidinyl -4-Pyridine, 6-Perimidinyl-4-pyridine, 7-Perimidinyl-4-pyridine, 8-Perimidinyl-4-pyridine, 9-Perimidinyl-4-pyridine, Phenantronyl-4-pyridine, 1-Phenazinyl-4-pyridine , 2-Phenazinyl-4-pyridine, 1-Phenothiadinyl-4-pyridine, 2-Phenothiadinyl-4-pyridine, 3-Phenothiadinyl-4-pyridine, 4-Phenothiadinyl-4-pyridine, 10-Phenothiadinyl- 4-Pyridine, 1-Phenoxadinyl-4-pyridine, 2-Phenoxazinyl-4-pyridine, 3-Phenoxazinyl-4-pyridine, 4-Phenoxazinyl-4-pyridine, 10-Phenoxazinyl-4-pyridine, 2-Antilydinyl-4-pyridine Examples thereof include pyridine, 3-antiridinyl-4-pyridine, 4-antiridinyl-4-pyridine, 5-antiridinyl-4-pyridine and derivatives thereof, and one or more of these may be used. Of these, a pyridine derivative containing a substituted or unsubstituted bipyridine compound represented by the general formula (1) and / or a substituted or unsubstituted phenylpyridine compound represented by the general formula (1) is preferable.

The polymer having a carboxyl group of the present invention is not particularly limited as long as it is a polymer having a carboxyl group, and since it exhibits a higher phase difference, it is a polymer containing a residue unit represented by the general formula (2). Is preferable.

(Here, R ₅ represents hydrogen or any substituent.)
R ₅ in the general formula (2) of the present invention indicates hydrogen or an arbitrary substituent, and examples of the optional substituent include a halogen, an alkyl group, a hydroxyl group, an alkoxyl group, an acyl group, a carbonyl group, and a carboxyl group. Examples thereof include a formyl group, an ester group, a benzoyl group, an amino group, an imino group, a cyano group, a nitro group, a phenyl group, and a substituent derived from these. Of these, a carboxyl group, a phenyl group, and a substituent derived from these are preferable because they exhibit a particularly high phase difference. More specific residue units represented by the general formula (2) include maleic acid residue unit, maleic acid monoester residue unit, fumaric acid residue unit, fumaric acid monoester residue unit, and silicic acid. Residue units, alkyl silicate residue units, and alkoxy silicate residue are preferred. These residue units may contain one kind or two or more kinds.

Specific examples of the polymer having a carboxyl group of the present invention include polyfumaric acid, polyfumaric acid monoester, fumaric acid monoester-silicic acid copolymer, fumaric acid monoester-alkyl silicic acid copolymer, and the like. Fumaric acid monoester-alkoxysilicic acid copolymer, maleic acid monoester-silicicicic acid copolymer, maleic acid monoester-alkylsilicicic acid copolymer, maleic acid monoester-alkoxysilicic acid copolymer , Maleic acid-silicic acid copolymer, maleic acid-alkyl silicic acid copolymer, maleic acid-alkoxysilicic acid copolymer, (meth) acrylic acid ester-fumaric acid copolymer, (meth) acrylic Acid ester-Fumarate monoester copolymer, (meth) acrylic acid ester-silicic acid copolymer, (meth) acrylic acid ester-alkoxysilicic acid copolymer, styrene-fumaric acid copolymer, styrene- Fumaric acid monoester copolymer, styrene-silicic acid copolymer, styrene-alkoxysilicic acid copolymer, α-methylstyrene-fumaric acid copolymer, α-methylstyrene-fumaric acid monoester copolymer , Α-Methylstyrene-silicic acid copolymer, α-methylstyrene-alkoxycynic acid copolymer, vinyl acetate-fumaric acid copolymer, vinyl acetate-fumaric acid monoester copolymer, vinyl acetate-Kay Skin acid copolymer, vinyl acetate-alkoxysilicate copolymer, vinyl propionate-fumaric acid copolymer, vinyl propionate-fumaric acid monoester copolymer, vinyl propionate-silicate copolymer, Vinyl propionate-alkoxysilicic acid copolymer, (meth) acrylonitrile-fumaric acid copolymer, (meth) acrylonitrile-fumaric acid monoester copolymer, (meth) acrylonitrile-silicic acid copolymer, (meth) ) Acrylonitrile-alkoxysilicic acid copolymer, methylvinyl ether-fumaric acid copolymer, methylvinyl ether-fumaric acid monoester copolymer, methylvinyl ether-silicic acid copolymer, methylvinyl ether-alkoxysilicic acid copolymer Combined, ethyl vinyl ether-fumaric acid monoester copolymer, ethyl vinyl ether-silicic acid copolymer, ethyl vinyl ether-alkoxysilicic acid copolymer, butyl vinyl ether-fumaric acid copolymer, butyl vinyl ether-fumaric acid monoester Copolymers, butyl vinyl ether-silicic acid copolymers, butyl vinyl ether-a Lucoxykei skin acid copolymer, N-methylmaleimide-fumaric acid copolymer, N-methylmaleimide-fumaric acid monoester copolymer, N-methylmaleimide-caylate copolymer, N-methylmaleimide-alkoxykei Skin acid copolymer, N-cyclohexylmaleimide-fumaric acid copolymer, N-cyclohexylmaleimide-fumaric acid monoester copolymer, N-cyclohexylmaleimide-silicic acid copolymer, N-cyclohexylmaleimide-alkoxycytic skin Acid copolymer, N-phenylmaleimide-fumaric acid copolymer, N-phenylmaleimide-fumaric acid monoester copolymer, N-phenylmaleimide-silicic acid copolymer, N-phenylmaleimide-alkoxycylic acid Copolymer, fumaric acid diester-fumaric acid copolymer, fumaric acid diester-fumaric acid monoester copolymer, fumaric acid diester-silicic acid copolymer, fumaric acid diester-alkoxycynic acid copolymer, Kay Fumaric acid ester-fumaric acid copolymer, silicic acid ester-fumaric acid monoester copolymer, silicic acid ester-caylate copolymer, silicic acid ester-alkoxycylic acid copolymer, methoxykei Fumaric acid ester-fumaric acid copolymer, methoxycinnamic acid ester-fumaric acid monoester copolymer, methoxycinnamic acid ester-silicic acid copolymer, methoxycinamic acid ester-alkoxycylic acid copolymer , Ethoxysilic acid ester-fumaric acid copolymer, ethoxysilic acid ester-fumaric acid monoester copolymer, ethoxysilic acid ester-fumaric acid copolymer, ethoxysilic acid ester-alkoxysilic acid copolymer, etc. Can be mentioned.

The polymer contained in the resin composition of the present invention may contain other monomer residue units as long as it does not exceed the scope of the present invention, and examples of the other monomer residue units include , Styrene residue unit, styrene residue unit such as α-methylstyrene residue unit; (meth) methyl acrylate residue unit, (meth) ethyl acrylate residue unit, (meth) butyl acrylate residue unit (Meta) cinnamic acid ester residue unit such as; vinyl acetate residue unit, vinyl ester residue unit such as vinyl propionate residue unit; acrylonitrile residue unit; methacrylonitrile residue unit; methyl vinyl ether residue unit , Ethylvinyl ether residue unit, vinyl ether residue unit such as butyl vinyl ether residue unit; phenylamic acid diester residue unit such as diethyl humate residue unit, diisopropyl fumarate residue unit; N-methylmaleimide residue unit, N-substituted maleimide residue units such as N-cyclohexyl maleimide residue unit and N-phenylmaleimide residue unit; cinnamic acid ester residue units such as ethyl silicate and propyl silicate; ethyl methylsilicate, Alkyl cinnamic acid ester residue units such as propyl methyl cinnamic acid and ethyl ethyl cinnamic acid; alkoxy cinnamic acid ester residue units such as ethyl methoxycinnamic acid, propyl methoxycinnamic acid and ethyl ethoxycinnamic acid; ethylene residues One or more selected from olefin residue units such as units and propylene residue units can be mentioned. Among these, fumaric acid diester residue unit, cinnamic acid ester residue unit, alkylcinnamic acid ester residue unit, and alkoxy cinnamic acid ester residue unit are preferable because they exhibit a high phase difference.

Since the polymer of the present invention has excellent mechanical properties, the number average molecular weight in terms of standard polystyrene obtained from the elution curve measured by gel permeation chromatography (GPC) is 30,000 to 500. It is preferably 000, more preferably 40,000-400,000.

Since the ratio of the pyridine derivative represented by the general formula (1) to the carboxyl group-containing residue unit in the resin composition of the present invention exhibits a high phase difference, 0.01: 99.99 to 10:90. (Mole ratio) is preferable, and 0.1: 99.9 to 5:95 (molar ratio) is more preferable. Here, in the present invention, the "carboxyl group-containing residue unit" means an arbitrary residue unit having one or two or more carboxyl groups.

When an optical film using the resin composition of the present invention is obtained, it is preferable to use a retardation film because even a thin film has a high out-of-plane retardation and is excellent in optical characteristics.

In the retardation film of the present invention, the refractive index in the phase-advancing axis direction in the film plane is nx, the refractive index in the in-plane direction of the film orthogonal to it is ny, and the refractive index in the thickness direction of the film is nz. It is a retardation film characterized in that the relationship is nx ≦ ny <nz, and by satisfying the above nx ≦ ny <nz, the viewing angle of STN-LCD, IPS-LCD, reflective LCD, transflective LCD, etc. It is a retardation film with excellent compensation performance. In general, the three-dimensional refractive index of a film is controlled by stretching the film, which complicates the manufacturing process and quality control. However, the retardation film of the present invention is unstretched and has a refractive index in the film thickness direction. It has been found that it shows a peculiar behavior that is high.

Further, since the retardation film of the present invention is a retardation film having more excellent optical characteristics, the out-of-plane retardation (Rth) measured at a wavelength of 550 nm represented by the following formula (a) is -100 to −. It is preferably 2000 nm, more preferably -100 to −500 nm, and particularly preferably −180 to −500 nm.
Rth = ((nx + ny) /2-nz) × d (a)
(Here, d indicates the thickness of the film.)
Since the retardation film of the present invention has a high out-of-plane retardation even in a thin film, the relationship between the film thickness and the out-of-plane retardation is preferably 5.5 nm / film thickness (μm) or more in absolute value, and is 6 nm /. The film thickness (μm) or more is more preferable, and 8 nm / film thickness (μm) or more is particularly preferable.

The retardation film of the present invention has good image quality characteristics when used in a liquid crystal display element, and therefore has a light transmittance of 85% or more, more preferably 90% or more. .. Further, the haze (cloudiness) of the retardation film is preferably 2% or less, and more preferably 1% or less.

The method for producing the retardation film of the present invention is not particularly limited, and examples thereof include a solution casting method and a melt casting method.

The solution casting method is a method in which a solution in which a resin composition is dissolved in a solvent (hereinafter referred to as dope) is cast on a support substrate, and then the solvent is removed by heating or the like to obtain a film. At that time, as a method of casting the dope on the support substrate, for example, a T-die method, a doctor blade method, a bar coater method, a roll coater method, a lip coater method and the like are used. In particular, industrially, the most common method is to continuously extrude the dope from the die onto a belt-shaped or drum-shaped support substrate. Examples of the support substrate used include a glass substrate, a metal substrate such as stainless steel and a 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 20000 cPs, 100. It is more preferably 10000 cPs.

At this time, the coating thickness of the resin composition of the present invention is preferably 1 to 200 μm after drying, more preferably 2 to 100 μm, and particularly preferably 3 to 50 μm because the film can be easily handled.

The melt casting method is a molding method in which a resin composition is melted in an extruder, extruded into a film from a slit of a T-die, and then taken out while being cooled by a roll, air, or the like.

The retardation film of the present invention can be used by peeling from the glass substrate of the base material or another optical film, and can also be used as a laminate with the glass substrate of the base material or another optical film.

Further, the retardation film of the present invention can be laminated with a polarizing plate and used as a circular or elliptical polarizing plate, and can also be laminated with a polarizing element containing polyvinyl alcohol / iodine or the like to form a polarizing plate. is there. Further, the retardation films of the present invention can be laminated with each other or with other retardation films.

The retardation film of the present invention preferably contains an antioxidant during film molding or in order to improve the thermal stability of the retardation film itself. Examples of the antioxidant include a hindered phenol-based antioxidant, a phosphorus-based antioxidant, and other antioxidants, and these antioxidants may be used alone or in combination, respectively. Since the antioxidant action is synergistically improved, it is preferable to use a hindered antioxidant and a phosphorus antioxidant in combination. In that case, for example, with respect to 100 parts by weight of the hindered antioxidant. , It is more preferable to mix and use a phosphorus-based antioxidant in an amount of 100 to 500 parts by weight. The amount of the antioxidant added is preferably 0.01 to 10 parts by weight, preferably 0.5 parts by weight, because it has an excellent antioxidant action with respect to 100 parts by weight of the resin composition constituting the retardation film of the present invention. ~ 1 part by weight is more preferable.

Further, as the ultraviolet absorber, for example, an ultraviolet absorber such as benzotriazole, benzophenone, triazine and benzoate may be blended as required.

The retardation film of the present invention contains other polymers, surfactants, polymer electrolytes, conductive complexes, inorganic fillers, pigments, antistatic agents, antiblocking agents, lubricants, etc., as long as the gist of the invention is not exceeded. You may.

According to the present invention, optical characteristics such as a large refractive index in the thickness direction, a large in-plane phase difference, and a small wavelength dependence of a film useful as a compensation film or an antireflection film for contrast and viewing angle characteristics of a liquid crystal display. It is possible to provide a resin composition suitable for an excellent retardation film.

Changes in refractive index ellipsoid due to stretching

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples.

The physical properties shown in the examples were measured by the following methods.

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

<Measurement of refractive index>
It was measured according to JIS K 7142 (1981 version) using an Abbe refractive index meter (manufactured by Atago).

<Measurement of film phase difference and three-dimensional refractive index>
The measurement was performed using a fully automatic double refractometer (manufactured by Oji Measuring Instruments, trade name KOBRA-WR).

Synthesis Example 1 (Synthesis of a polymer having a carboxyl group (methoxysilicate ester-fumaric acid monoester copolymer: 4-methoxysilicate n-propyl / fumaric acid monoisopropyl copolymer) 1)
50 g (0.23 mol) of n-propyl 4-methoxysilicate, 4.0 g (0.025 mol) of monoisopropyl fumarate and tert-butylperoxypivalate 0 as a polymerization initiator in a glass ampol having a capacity of 75 mL. .34 g (0.0019 mol) was added, and after repeating nitrogen substitution and depressurization, the mixture was sealed under reduced pressure. This ampoule was placed in a constant temperature bath at 50 ° C. and held for 96 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 400 g of tetrahydrofuran. This polymer solution was added dropwise to 3 L of methanol to precipitate, and then vacuum dried at 80 ° C. for 10 hours to obtain 16.7 g of a polymer having a carboxyl group (yield: 31%).

The obtained polymer having a carboxyl group has a number average molecular weight of 54,000, and has an n-propyl residue unit of 4-methoxysilicate crust / monoisopropyl fumarate residue unit = 76/24 (molar ratio). there were.

Synthesis Example 2 (Synthesis of a polymer having a carboxyl group (fumaric acid diester-cinnamic acid copolymer: diisopropyl fumarate / cinnamic acid copolymer) 2)
50 g (0.25 mol) of diisopropyl fumarate, 6.5 g (0.04 mol) of silicic acid and 0.34 g (0.0020 mol) of tert-butylperoxypivalate as a polymerization initiator in a glass ampoule having a capacity of 75 mL. ) Was added, and after repeating nitrogen replacement and depressurization, the mixture was sealed under reduced pressure. This ampoule was placed in a constant temperature bath at 50 ° C. and held 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 400 g of tetrahydrofuran. This polymer solution was added dropwise to 3 L of methanol to precipitate, and then vacuum dried at 80 ° C. for 10 hours to obtain 19.0 g of a polymer having a carboxyl group (yield: 34%).

The number average molecular weight of the obtained polymer having a carboxyl group was 121,000, and the copolymer composition was diisopropyl fumarate residue unit / cinnamic acid residue unit = 90/10 (mol%).

Synthesis Example 3 (Synthesis of a polymer having a carboxyl group (methoxysilicate ester-fumaric acid monoester copolymer: 4-methylsilicate ethyl silate / monoethyl fumarate copolymer) 3)
50 g (0.26 mol) of ethyl 4-methylsilicate, 2.4 g (0.017 mol) of monoethyl fumarate and 0.33 g (0) of tert-butylperoxypivalate as a polymerization initiator in a glass ampoule having a capacity of 75 mL. .0019 mol) was added, and after repeating nitrogen substitution and depressurization, the mixture was sealed under reduced pressure. This ampoule was placed in a constant temperature bath at 50 ° C. and held for 96 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 400 g of tetrahydrofuran. This polymer solution was added dropwise to 3 L of methanol to precipitate, and then vacuum dried at 80 ° C. for 10 hours to obtain 13.6 g of a polymer having a carboxyl group (yield: 26%).

The number average molecular weight of the obtained polymer having a carboxyl group is 47,000, and the copolymer composition is 4-methylsilicate ethyl silicate residue unit / monoethyl fumarate residue unit = 81/19 (mol%). I confirmed that there was.

Example 1
99 parts by weight of the polymer and 1 part by weight of 4,4'-bipyridine obtained in Synthesis Example 1 were dissolved in 400 parts by weight of methylisobutylketone to prepare a resin solution, which was cast on a polyethylene terephthalate film by a coater, and 130 parts by weight. By drying at ° C. for 10 minutes, a film using a resin composition containing a polymer having a carboxyl group having a thickness of 20 μm and a pyridine derivative was obtained.

The obtained film had a total light transmittance of 91%, a haze of 0.5%, and a refractive index of 1.528.

The three-dimensional refractive index was nx = 1.5241, ny = 1.5241, nz = 1.5349, and the obtained film showed a value of nx = ny <nz and a large refractive index in the thickness direction of the film. .. The out-of-plane phase difference Rth was negatively large at -216 nm. The ratio of the absolute value of the out-of-plane phase difference to the film thickness was 10.8 nm / film thickness (μm).

From these results, the obtained film has negative birefringence, a large refractive index in the thickness direction, a large out-of-plane phase difference, and a high out-of-plane phase difference even in a thin film. It was suitable for a retardation film.

Example 2
99.5 parts by weight of the polymer and 0.5 part by weight of 4-phenylpyridine obtained in Synthesis Example 2 were dissolved in butyl acetate to prepare a resin solution of 525 parts by weight, which was cast on a polyethylene terephthalate film by a coater. By drying at 140 ° C. for 10 minutes, a film using a resin composition containing a polymer having a carboxyl group having a thickness of 20 μm and a pyridine derivative was obtained.

The obtained film had a total light transmittance of 92%, a haze of 0.5%, and a refractive index of 1.482.

The three-dimensional refractive index was nx = 1.4796, ny = 1.4796, nz = 1.4881, and the obtained film showed nx = ny <nz, which is a large value of the refractive index in the thickness direction of the film. .. The out-of-plane phase difference Rth was negatively large at −170 nm. The ratio of the absolute value of the out-of-plane phase difference to the film thickness was 8.5 nm / film thickness (μm).

From these results, the obtained film has negative birefringence, a large refractive index in the thickness direction, a large out-of-plane phase difference, and a high out-of-plane phase difference even in a thin film. It was suitable for a retardation film.

Example 3
With respect to 98 parts by weight of the polymer obtained in Synthesis Example 3, 2 parts by weight of 4- (p-tolyl) pyridine was dissolved in toluene to obtain 400 parts by weight of a resin solution, which was cast on a polyethylene terephthalate film by a coater. By drying at 130 ° C. for 10 minutes, a film using a resin composition containing a polymer having a carboxyl group having a thickness of 20 μm and a pyridine derivative was obtained.

The obtained film had a total light transmittance of 91%, a haze of 0.6%, and a refractive index of 1.539.

The three-dimensional refractive index was nx = 1.5360, ny = 1.5360, nz = 1.5463, and the obtained film showed a value of nx = ny <nz and a large refractive index in the thickness direction of the film. .. The out-of-plane phase difference Rth was negatively large at −206 nm. The ratio of the absolute value of the out-of-plane phase difference to the film thickness was 10.3 nm / film thickness (μm).

From these results, the obtained film has negative birefringence, a large refractive index in the thickness direction, a large out-of-plane phase difference, and a high out-of-plane phase difference even in a thin film. It was suitable for a retardation film.

Comparative Example 1
99 parts by weight of the polymer obtained in Synthesis Example 1 and 1 part by weight of 2,2'-bipyridine were dissolved in 400 parts by weight of methylisobutylketone to prepare a resin solution, which was cast on a polyethylene terephthalate film by a coater, and 130 parts by weight. By drying at ° C. for 10 minutes, a film using a resin composition containing a polymer having a carboxyl group having a thickness of 20 μm and a pyridine derivative was obtained.

The obtained film had a total light transmittance of 91%, a haze of 0.6%, and a refractive index of 1.528.

The three-dimensional refractive index was nx = 1.5263, ny = 1.5263, nz = 1.5306, and the obtained film had nx = ny <nz, which was a large refractive index in the film thickness direction. However, the out-of-plane phase difference was as small as −86 nm, and the ratio of the absolute value of the out-of-plane phase difference to the film thickness was as small as 4.3 nm / film thickness (μm).

Comparative Example 2
99.5 parts by weight of the polymer and 0.5 part by weight of 2-phenylpyridine obtained in Synthesis Example 2 were dissolved in butyl acetate to prepare a resin solution of 525 parts by weight, which was cast on a polyethylene terephthalate film by a coater. By drying at 140 ° C. for 10 minutes, a film using a resin composition containing a polymer having a carboxyl group having a thickness of 20 μm and a pyridine derivative was obtained.

The obtained film had a total light transmittance of 92%, a haze of 0.5%, and a refractive index of 1.482.

The three-dimensional refractive index was nx = 1.4809, ny = 1.4809, nz = 1.4856, and the obtained film had nx = ny <nz, which was a large refractive index in the film thickness direction. However, the out-of-plane phase difference was as small as −94 nm, and the ratio of the absolute value of the out-of-plane phase difference to the film thickness was as small as 4.7 nm / film thickness (μm).

Comparative Example 3
With respect to 98 parts by weight of the polymer obtained in Synthesis Example 3, 2 parts by weight of 4- (3-phenylpropyl) pyridine was dissolved in toluene to obtain 400 parts by weight of a resin solution, which was cast on a polyethylene terephthalate film by a coater. Then, it was dried at 130 ° C. for 10 minutes to obtain a film using a resin composition containing a polymer having a carboxyl group having a thickness of 20 μm and a pyridine derivative.

The obtained film had a total light transmittance of 91%, a haze of 0.6%, and a refractive index of 1.507.

The three-dimensional refractive index is nx = 1.5058, ny = 1.5058, nz = 1.5097, and the obtained film shows nx = ny <nz, which means that the refractive index in the film thickness direction is large. However, the out-of-plane retardation Rth was as small as −78 nm, and the ratio of the absolute value of the out-of-plane retardation to the film thickness was as small as 3.9 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 phase difference was small and a high out-of-plane phase difference could not be expected even in a thin film. Met.

nx; Indicates the refractive index in the phase-advancing axis direction in the film plane.
ny; Indicates the refractive index in the in-plane direction of the film orthogonal to nx.
nz; Indicates the refractive index in the thickness direction of the film.

Claims (5)

At least the pyridine derivative represented by the general formula (1) and
A general formula containing one or more residue units selected from a fumaric acid diester residue unit, a siliceous ester residue unit, an alkylsilicate ester residue unit, and an alkoxysilicate ester residue unit. A resin composition comprising a polymer having a residue unit containing a carboxyl group represented by (2) .
(Wherein, R ₁ to R ₄ represents hydrogen, Ar is methyl substituted Moshiku represents any of the unsubstituted phenyl group or a methyl-substituted or unsubstituted pyridyl group.)
(Here, R ₅ indicates an arbitrary substituent or hydrogen.) The residue unit represented by the general formula (2) is maleic acid residue unit, maleic acid monoester residue unit, fumaric acid residue unit, fumaric acid monoester residue unit, cinnamic acid residue unit, alkyl. The resin composition according to claim 1 , wherein the resin composition is selected from a cinnamic acid residue unit and an alkoxy cinnamic acid residue unit. The first or second claim is characterized in that the ratio of the pyridine derivative represented by the general formula (1) to the carboxyl group-containing residue unit is 0.01: 99.99 to 10:90 (molar ratio). The resin composition described. A retardation film using the resin composition according to any one of claims 1 to 3 . When the refractive index in the phase-advancing axis direction in the film plane is nx, the refractive index in the in-plane direction of the film orthogonal to it is ny, and the refractive index in the thickness direction of the film is nz, the respective relationships are nx ≦ ny <nz. The retardation film according to claim 4 , wherein the film is provided.