JP6904137B2 - Resin composition and optical compensation film using it - Google Patents

Description

The present invention relates to a resin composition and an optical compensation film using the same, and more particularly to a resin composition and an optical compensation film for a liquid crystal display excellent in phase difference characteristics and wavelength dispersion characteristics.

Liquid crystal displays are widely used as the most important display devices in the multimedia society, including mobile phones, computer monitors, notebook personal computers, and televisions. Many optical films are used in liquid crystal displays to improve display characteristics. In particular, the optical compensation film plays a major role in improving contrast when viewed from the front or at an angle, and compensating for color tone.

Liquid crystal displays include vertically oriented (VA-LCD), in-plane oriented liquid crystal (IPS-LCD), super twisted nematic liquid crystal (STN-LCD), reflective liquid crystal display, transflective liquid crystal display, etc. There are many methods, and an optical compensation film suitable for the display is required.

As the conventional optical compensation film, a stretched film such as a cellulosic resin, polycarbonate or cyclic polyolefin is used. In particular, films made of cellulosic resins such as triacetyl cellulosic films are widely used because they have good adhesiveness to polyvinyl alcohol, which is a polarizer.

However, the optical compensation film made of a cellulosic resin has some problems. For example, a cellulosic resin film is processed into an optical compensation film having a phase difference value suitable for various displays by adjusting stretching conditions, and can be obtained by uniaxial or biaxial stretching of the cellulosic resin film. The three-dimensional refractive index of the film is ny ≧ nx> nz, and an optical compensation film having another three-dimensional refractive index, for example, ny> nz> nx or ny = nz> nx, is used. In order to manufacture the film, a special stretching method is required, such as adhering a heat-shrinkable film to one or both sides of the film, heat-stretching the laminate, and applying a shrinking force in the thickness direction of the polymer film. It is also difficult to control the refractive index (phase difference value) (see, for example, Patent Documents 1 to 3). Here, nx is the refractive index in the phase-advancing axis direction (the direction with the smallest refractive index) in the film surface, ny is the refractive index in the slow-phase axial direction (the direction with the largest refractive index) in the film surface, and nz is the film surface. Indicates the refractive index of the outside (thickness direction).

Further, the cellulosic resin film is generally manufactured by the solvent casting method, but the cellulosic resin film formed by the casting method has an out-of-plane phase difference (Rth) of about 40 nm in the film thickness direction. There is a problem that color shift occurs in the liquid crystal display of IPS mode. Here, the out-of-plane phase difference (Rth) is a phase difference value represented by the following equation (A).

Rth = [(nx + ny) /2-nz] x D (A)
(In the formula, nx indicates the refractive index in the phase-advancing axis direction in the film surface, ny indicates the refractive index in the slow-phase axial direction in the film surface, nz indicates the refractive index outside the film surface, and D indicates the film thickness. )
Further, a retardation film (optical compensation film) made of a fumaric acid ester resin has been proposed (see, for example, Patent Document 4).

However, the three-dimensional refractive index of the stretched film made of the fumaric acid ester resin is nz> ny> nx, and in order to obtain the optical compensation film exhibiting the above three-dimensional refractive index, it is laminated with another optical compensation film or the like. Etc. are required.

Therefore, as the optical compensation film exhibiting the three-dimensional refractive index, a resin composition and an optical compensation film using the resin composition have been proposed (see, for example, Patent Documents 5 to 7). Although Patent Documents 5 to 7 have excellent performance as an optical compensation film, an optical compensation film that expresses the desired Re with a thinner film is required.

Here, the optical compensation film is generally used as an antireflection layer for a reflective liquid crystal display device, a touch panel, or an organic EL, and in this application, an optical compensation film having a larger retardation especially in a long wavelength region (a long wavelength region). Hereinafter, "reverse wavelength dispersion film") is required. For example, when an inverse wavelength dispersion film is used as an optical compensation film for a circularly polarizing plate for organic EL, the phase difference is preferably about 1/4 of the measurement wavelength λ, and the retardation at 450 nm and the retardation at 550 nm. The ratio of the ratios Re (450) / Re (550) is preferably close to 0.81. Various optical compensation films have been developed to meet such required characteristics.

A retardation film containing a cellulose resin and a fumaric acid ester polymer, which are cellulose ethers, has been proposed as an optical compensation film that exhibits the above-mentioned three-dimensional refractive index, has a large expression of Re in a thin film, and is used as an inverse wavelength dispersion film. (See, for example, Patent Document 8).

However, at present, as an optical compensation film used as a reverse wavelength dispersion film, an optical compensation film that is colorless and highly transparent even at a high temperature is required from the viewpoint of process compatibility. Although the retardation film obtained in Patent Document 8 has excellent retardation development and the like, it has problems in yellowness and transparency at high temperatures, and an optical compensation film having high stability at higher temperatures is required. There is.

Japanese Patent No. 2818983 Japanese Unexamined Patent Publication No. 5-297223 Japanese Unexamined Patent Publication No. 5-323120 Japanese Unexamined Patent Publication No. 2008-64817 Japanese Unexamined Patent Publication No. 2013-28741 Japanese Unexamined Patent Publication No. 2014-125609 Japanese Unexamined Patent Publication No. 2014-125610 Japanese Unexamined Patent Publication No. 2015-157928

The present invention has been made in view of the above problems, and an object of the present invention is an optical compensation film using a resin composition having excellent phase difference characteristics and wavelength dispersion characteristics, which has high heat resistance and excellent stability. The purpose is to provide an optical compensation film.

As a result of diligent studies to solve the above problems, the present inventors have made an optical compensation film using a resin composition containing a specific cellulosic resin, a specific ester resin, and a specific polyphenyl compound. And its manufacturing method have found to solve the above-mentioned problems, and have completed the present invention. That is, the present invention contains 29.99 to 98.9% by weight of the cellulosic resin represented by the following general formula (1) and 1 to 70% by weight of the ester resin exhibiting negative birefringence. , A resin composition containing 0.01 to 30% by weight of a polyphenyl compound.

(In the formula, R _{1 to} R ₃ independently represent hydrogen or a substituent having 1 to 12 carbon atoms.)
Further, as a preferred embodiment of the present invention, it contains 29.99 to 99.99% by weight of the cellulosic resin represented by the general formula (1) and 1 to 70% by weight of the ester resin exhibiting negative birefringence. Further, the resin further contains 0.01 to 30% by weight of the polyphenyl compound containing at least one selected from the group consisting of the polyphenyl structures represented by the following general formulas (2) to (7). It is a composition.

(In the formula, X ₁ and X ₂ are independently represented by the following general formula (X), where m = 1 to 6).

(In the formula, R ₄ and R ₅ independently represent a benzene ring, a naphthalene ring or a fluorene ring, respectively, and are substituted with a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group or a phenyl group, respectively. May be.)

(In the formula, R ₆ represents a benzene ring, a naphthalene ring or a fluorene ring, and may be substituted with a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group or a phenyl group. A ₁ , A ₂ is independently represented by a hydrogen, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group, a phenyl group or the general formula (X), where m = 1 to 6. )

(In the formula, A _{3 to} A ₅ are independently represented by hydrogen, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group, a phenyl group or the general formula (X), where m. = 1-6.)

(In the formula, R _{7 to} R ₉ are independently hydrogen, hydroxy group, nitro group, bromo group, iodo group, cyano group, chloro group, sulfonic acid group, carboxylic acid group, fluoro group and 1 to 1 carbon atoms. It shows 12 alkyl groups, acyloxy groups, or alkoxy groups, where n = 0-4.)

(In the formula, R _{10 to} R ₁₂ are independently hydrogen, hydroxy group, nitro group, bromo group, iodo group, cyano group, chloro group, sulfonic acid group, carboxylic acid group, fluoro group and 1 to 1 carbon atoms. It shows 12 alkyl groups, acyloxy groups, or alkoxy groups, where n = 0-4.)

(In the formula, R _{13 to} R ₁₅ are independently hydrogen, hydroxy group, nitro group, bromo group, iodo group, cyano group, chloro group, sulfonic acid group, carboxylic acid group, fluoro group and 1 to 1 carbon atoms. It shows 12 alkyl groups, acyloxy groups, or alkoxy groups, where n = 0-4.)
Hereinafter, the present invention will be described in detail.

The resin composition of the present invention contains 29.99 to 99.99% by weight of the cellulosic resin represented by the following general formula (1) and 1 to 70% by weight of the ester resin exhibiting negative birefringence. Further, it contains 0.01 to 30% by weight of the polyphenyl compound.

(In the formula, R _{1 to} R ₃ independently represent hydrogen or a substituent having 1 to 12 carbon atoms.)
Examples of the cellulosic resin of the present invention include cellulosic ester, cellulosic ester, cellulosic ester and the like. The resin composition of the present invention may contain one or more of these cellulosic resins.

Since the polystyrene-based resin of the present invention has excellent mechanical properties and excellent molding processability during film formation, it can be obtained from an elution curve measured by gel permeation chromatography (GPC). preferably the number average molecular weight in terms of polystyrene (Mn) is ^{1 × 10 3 ~1 × 10 6} , further preferably ^{5 × 10 3 ~2 × 10 5} .

The cellulosic resin of the present invention is excellent in compatibility with an ester resin exhibiting negative birefringence, has a large in-plane retardation Re, and is also excellent in drawability. Is preferable.

Hereinafter, a cellulosic ether preferable as the cellulosic resin used in the optical compensation film of the present invention will be described.

The cellulosic resin of the present invention is a polymer in which β-glucose units are linearly polymerized, and is one of the hydroxyl groups at the 2, 3, and 6 positions of the glucose units. It is a polymer in which parts or all are etherified. Examples of the cellulosic ether of the present invention include alkyl cellulose such as methyl cellulose, ethyl cellulose, and propyl cellulose; and hydroxyalkyl cellulose such as hydroxyethyl cellulose and hydroxypropyl cellulose. Aralkyl cellose such as benzyl cellose and trityl cellose; cyanoalkyl cellose such as cyanoethyl cellose; carboxyalkyl cellose such as carboxymethyl cellulose and carboxyethyl cellose; carboxymethyl methyl Carboxyalkylalkyl cellulose such as cellulosic and carboxymethylethyl cellulose; aminoalkylcellulosic such as aminoethyl cellulose and the like can be mentioned.

The degree of substitution (degree of etherification) of the cellulosic hydroxyl group substituted via the oxygen atom in the cellulosic ether is the cellulosic hydroxyl group at the 2-position, 3-position, and 6-position, respectively. Means the rate of etherification (100% etherification is a degree of substitution 1), and the total degree of substitution DS of the ether group is preferable from the viewpoint of solubility, compatibility, and stretchability. Is 1.5 to 3.0 (1.5 ≦ DS ≦ 3.0), more preferably 1.8 to 2.8. The cellulosic ether preferably has a substituent having 1 to 12 carbon atoms from the viewpoint of solubility and compatibility. Examples of the substituent having 1 to 12 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decanyl group, a dodecanyl group, an isobutyl group and a t-butyl group. , Cyclohexyl group, phenonyl group, benzyl group, naphthyl group and the like. Among these, a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group, which are alkyl groups having 1 to 5 carbon atoms, are preferable from the viewpoint of solubility and compatibility. The cellulosic polymer used in the present invention may have only one type of ether group or may have two or more types of ether groups. Further, it may have an ester group in addition to the ether group.

Cellulose ether is generally synthesized by alkali-decomposing cellulosic pulp obtained from wood or cotton and etherifying the alkali-decomposed cellulosic pulp. As the alkali, hydroxides of alkali metals such as lithium, potassium and sodium, and ammonia can be used. The alkalis are generally used as an aqueous solution. Then, the alkalineized cellulosic pulp is etherified by being contacted with an etherifying agent used depending on the type of cellulosic ether. Examples of the etherifying agent include alkyl halides such as methyl chloride and ethyl chloride; aralkyl halides such as benzyl chloride and trityl chloride; halocarboxylic acids such as monochloroacetic acid and monochloropropionic acid; ethylene oxide, propylene oxide and butylene. Examples thereof include alkylene oxides such as oxides, and these etherifying agents can be used alone or in combination of two or more.

If necessary, after completion of the reaction, depolymerization treatment may be carried out with hydrogen chloride, hydrogen bromide, hydrochloric acid, sulfuric acid or the like to adjust the viscosity.

The ester-based resin exhibiting negative double-refractive properties (hereinafter referred to as ester-based resin exhibiting negative compound refractive properties) contained in the resin composition of the present invention is a resin having an ester residue unit exhibiting negative compound refractive properties. If this is the case, there is no particular limitation, and examples of the residue unit include (meth) acrylic acid ester residue unit, silicate ester residue unit, fumaric acid ester residue unit, and the like. Alternatively, two or more types can be mentioned.

In the present invention, the positive and negative of birefringence are defined as shown below.

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, when uniaxially stretched, the refractive index in the axial direction orthogonal to the stretching axis is small (phase-advancing axis: in the direction perpendicular to the stretching direction), the resin showing positive birefringence, and when uniaxially stretched, the refractive index in the stretching axial direction is small. (Phase-advancing axis: stretching direction) is called a resin exhibiting negative birefringence.

As an ester resin exhibiting negative birefringence, negative birefringence is highly exhibited and the optical compensation film can be thinned. Therefore, the fumaric acid ester residue unit represented by the following general formula (8) and the fumaric acid ester residue unit and / Or an ester resin containing a cinnamic acid ester residue unit represented by the following general formula (9) is preferable.

(In the formula, R _{16 and} R ₁₇ each independently represent hydrogen or an alkyl group having 1 to 12 carbon atoms.)

(In the formula, R ₁₈ represents hydrogen or an alkyl group having 1 to 12 carbon atoms. R ₁₉ is a hydrogen, nitro group, bromo group, iodo group, cyano group, chloro group, sulfonic acid group, carboxylic acid group, fluoro group. , A phenyl group or an alkoxy group having 1 to 12 carbon atoms.)
In the present invention, as the ester-based resin exhibiting negative compound refractive property, an optically compensating film having excellent retardation characteristics and transparency can be obtained. Therefore, the fumaric acid ester residue units 1 to 1 represented by the general formula (8) are obtained. An ester resin containing 80 mol% and 99 to 20 mol% of the cinnamic acid ester residue unit represented by the general formula (9) is preferable, and the fumaric acid ester residue unit is 1 to 70 mol% and the cinnamic acid ester. Ester-based resins containing 99 to 30 mol% of residue units are more preferable.

As the fumaric acid ester residue unit represented by the general formula (8), since it is superior in retardation characteristics and transparency, it is a monoethyl fumarate residue unit, a monoisopropyl fumarate residue unit, and a mono-n-propyl fumarate. Residual unit, mono-n-butyl fumarate residue unit, mono-2-ethylhexyl fumarate residue unit, diethyl fumarate residue unit, diisopropyl fumarate residue unit, di-t-butyl fumarate residue unit , One or more fumaric acid ester residue units selected from the group consisting of dicyclohexyl fumarate residue units.

As the cinnamic acid ester residue unit represented by the general formula (9), since it is excellent in phase difference characteristics, cinnamic acid in which R ₁₉ in the cinnamic acid ester residue unit is hydrogen or a 4-methoxy group. The ester residue unit is preferable, and among these, the cinnamic acid residue unit, the methyl cinnamic acid residue unit, the ethyl cinnamic acid residue unit, and the n-propyl cinnamic acid are excellent in phase difference characteristics and transparency. Residual unit, isopropyl cinnamic acid residue unit, 4-methoxycinnamic acid residue unit, 4-methoxycinnamic acid methyl residue unit, 4-methoxycinnamic acid ethyl residue unit, 4-methoxycinnamic acid More preferred are n-propyl residue units and isopropyl 4-methoxycinnamic acid residue units.

The ester resin exhibiting negative birefringence is a residue unit of a monomer copolymerizable with the monomer, with 100 mol% of the monomer related to the ester residue unit exhibiting negative birefringence. It may contain 0 to 20 mol%.

Examples of the residue unit of the monomer copolymerizable with the monomer related to the ester residue unit exhibiting negative birefractive property include styrene residues such as styrene residue and α-methylstyrene residue; Acrylic acid residue; Methacrylic acid residue; Vinyl ester residue such as vinyl acetate residue and vinyl propionate residue; Vinyl ether such as methyl vinyl ether residue, ethyl vinyl ether residue and butyl vinyl ether residue Residues; N-substituted maleimide residues such as N-methylmaleimide residue, N-cyclohexylmaleimide residue, N-phenylmaleimide residue; acrylonitrile residue; methacrylonitrile residue; silicic acid residue; ethylene residue One or more kinds such as olefin residues such as group and propylene residue; vinylpyrrolidone residue; vinylpyridine residue and the like can be mentioned.

Ester-based resins that exhibit negative birefringence have particularly excellent mechanical properties and excellent molding processability during film formation. Therefore, an elution curve measured by gel permeation chromatography (GPC). preferably the number average molecular weight in terms of standard polystyrene more obtained (Mn) is of ^{1 × 10 3 ~5 × 10 6} , further preferably ^{5 × 10 3 ~2 × 10 5} .

The ratio of the composition of the cellulosic resin to the ester resin exhibiting negative birefringence in the resin composition of the present invention is 29.99 to 99.99% by weight of the cellulosic resin and negative birefringence. It is 1 to 70% by weight of the ester resin shown. When the cellulosic resin is less than 29.99% by weight (when the ester resin showing negative birefringence exceeds 70% by weight), or when the cellulosic resin exceeds 98.99% by weight (when the cellulosic resin exceeds 99.99% by weight () When the ester resin exhibiting negative birefringence is less than 1% by weight), it is difficult to control the phase difference. Preferably, it is 29.99 to 89.99% by weight of the cellulosic resin and 10 to 70% by weight of the ester resin exhibiting negative birefringence, and more preferably 39.99 to 79% by weight of the cellulosic resin. It is 99% by weight and 20 to 60% by weight of the ester resin exhibiting negative birefringence.

As a method for producing the ester resin exhibiting negative birefringence, any method may be used as long as the ester resin can be obtained, and the ester resin can be produced by radical polymerization.

As the radical polymerization method, for example, any of a bulk polymerization method, a solution polymerization method, a suspension polymerization method, a precipitation polymerization method, an emulsion polymerization method and the like can be adopted.

Examples of the polymerization initiator for radical polymerization include benzoylpaoxide, laurylpaoxide, octanoylpaoxide, acetylpaoxide, di-t-butylpaoxide, t-butylcumylperoxide, dicumylperoxide, 2, Organic peroxides such as 5-dimethyl-2,5-di (2-ethylhexanoylpaoxy) hexane; 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis ( 2-Azobisisobutyronitrile), 2,2'-azobisisobutyronitrile, dimethyl-2,2'-azobisisobutylate, 1,1'-azobis (cyclohexane-1-carbonitrile) and other azo systems. Initiators and the like can be mentioned.

The solvent that can be used in the solution polymerization method or the precipitation polymerization method is not particularly limited, and for example, aromatic solvents such as benzene, toluene, and xylene; metanol, ethanol, propyl alcohol, butyl alcohol, and the like. Cyclohexane, dioxane, tetrahydrofuran, acetone, methyl ethyl ketone, dimethylformamide, isopropyl acetate and the like, and a mixed solvent thereof can also be mentioned.

Further, the polymerization temperature at the time of performing radical polymerization can be appropriately set according to the decomposition temperature of the polymerization initiator, and is generally preferably carried out in the range of 30 to 150 ° C.

Since the resin composition according to the present invention contains the polyphenyl compound, the polyphenyl compound is contained between the cellulosic resin chains, the polyphenyl compound has high heat resistance, and has low volatility and thermal motility. The resin becomes more thermally stable. Then, in the present invention, the stability (heat resistance) at a high temperature is improved, and the optical compensation film obtained by using the resin composition of the present invention is highly stable at a high temperature. Further, the polyphenyl compound preferably has the same polarity as the cellulosic resin according to the present invention. At this time, the polyphenyl compound becomes easier to enter (easily mix) between the resin chains of the cellulosic resin having similar polarities.

Further, in the present invention, when the polyphenyl compound is a polyphenyl compound containing at least one selected from the group consisting of polyphenyl structures represented by the general formulas (2) to (7), the obtained optical compensation film is: The stability (heat resistance) at high temperature is further improved, which is more suitable.

_{In the present invention, X 1} and X ₂ in the polyphenyl compound represented by the general formula (2) are independently represented by the general formula (X). _{R 4} and R ₅ in the general formula (X) independently represent a benzene ring, a naphthalene ring or a fluorene ring, respectively. _{R 4} and R ₅ are preferably benzene rings because they are more transparent. Further, it may be substituted with a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group or a phenyl group. Among these, since the retardation performance is excellent, the substituents include hydroxy group, phenyl group, methyl group, ethyl group, isopropyl group, n-propyl group, n-butyl group, isobutyl group, t-butyl group and methoxy. Groups are preferred.

_{In the present invention, R 6} in the polyphenyl compound represented by the general formula (3) independently represents a benzene ring, a naphthalene ring or a fluorene ring, respectively. _{R 6} is preferably a benzene ring because of its better transparency. Further, it may be substituted with a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group or a phenyl group. Among these, since the retardation performance is excellent, the substituents include hydroxy group, phenyl group, methyl group, ethyl group, isopropyl group, n-propyl group, n-butyl group, isobutyl group, t-butyl group and methoxy. Groups are preferred.

_{Further, A 1} and A ₂ in the polyphenyl compound represented by the general formula (3) are independently hydrogen, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group, a phenyl group or a general formula. It is indicated by (X). Among these, hydrogen, hydroxy group, phenyl group, methyl group, ethyl group, isopropyl group, n-propyl group, n-butyl group, isobutyl group, t-butyl group, methoxy group, general The formula (X) is preferable, and hydrogen, phenyl group, methyl group, methoxy group, and general formula (X) are more preferable.

In the present invention, A ₃ to A ₅ are in polyphenyl compound represented by the general formula (4), each independently, hydrogen, hydroxy, alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group, a phenyl group Alternatively, it is represented by the general formula (X). Among these, hydrogen, hydroxy group, phenyl group, methyl group, ethyl group, isopropyl group, n-propyl group, n-butyl group, isobutyl group, t-butyl group, methoxy group, general The formula (X) is preferable, and hydrogen, phenyl group, methyl group, methoxy group, and general formula (X) are more preferable.

In the polyphenyl compounds represented by the general formulas (2) to (4), m = 1 to 6, and m = 1 to 3 is preferable because the transparency is more excellent.

When A _{1 to} A ₅ are of the general formula (X), preferable R ₄ and R ₅ are the same as for the polyphenyl compound represented by the general formula (2).

_{In the present invention, R 7 to} R ₁₅ in the polyphenyl compounds represented by the general formulas (5) to (7) are independently hydrogen, hydroxy group, nitro group, bromo group, iodo group, cyano group and chloro group, respectively. , A sulfonic acid group, a carboxylic acid group, a fluoro group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, or an alkoxy group. Among these, hydrogen, hydroxy group, cyano group, carboxylic acid group, alkyl group having 1 to 12 carbon atoms, acyloxy group and alkoxy group are preferable, and hydrogen, hydroxy group, cyano group and carboxylic acid are preferable because of excellent phase difference performance. A group, a substituent having 1 to 6 carbon atoms, and a methoxy group are more preferable.

In the polyphenyl compounds represented by the general formulas (5) to (7), n = 0 to 4, and n = 1 to 2 is preferable because the transparency is more excellent.

In the present invention, the polyphenyl compound is characterized by containing at least one selected from the group consisting of polyphenyl structures represented by the general formulas (2) to (7). Since the polyphenyl compound has excellent phase difference characteristics, it is preferably formed with a polyphenyl structure represented by the general formula (2) or the general formula (5). Further, when the polyphenyl compound is formed with a polyphenyl structure represented by the general formula (5), R _{7 to} R ₉ are hydrogen, a hydroxy group, a cyano group, a carboxylic acid group, and an alkyl having 1 to 12 carbon atoms. It is preferably a group, an acyloxy group, or an alkoxy group.

The proportion of the polyphenyl compound in the resin composition of the present invention is 0.01 to 30% by weight (the above resin component: 70 to 99.9% by weight), preferably 0.1 to 15% by weight, and further. It is preferably 0.3 to 10% by weight. In the present invention, when the proportion of the polyphenyl compound is less than 0.01% by weight, the performance as an optical compensation film cannot be maintained in a high temperature environment, and the heat resistance is lowered. Further, when it is larger than 30% by weight, an optical compensation film having excellent retardation characteristics, which is a feature of the present invention, cannot be obtained.

These polyphenyl compounds may be used alone or in admixture of two or more.

Specific polyphenyl compounds of the present invention include, for example, N, N, N', N'-tetraphenylbenzidine, N, N'-diphenyl-N, N'-di (o-tolyl) benzidine, N, N'-diphenyl-N, N'-di (m-tolyl) benzidine, N, N'-diphenyl-N, N'-di (p-tolyl) benzidine, N, N'-bis (4-formylphenyl) -N, N'-diphenylbenzidine, N, N'-di (4-biphenylyl) -N, N'-diphenylbenzidine, N, N'-bis (4-methoxy-2-methylphenyl) -N, N' -Diphenylbenzidine, N, N'-di-1-naphthyl-N, N'-diphenylbenzidine, N, N'-bis [4- (diphenylamino) phenyl] -N, N'-diphenylbenzidine, N, N '-Bis [4- (diphenylamino) phenyl] -N, N'-di (1-naphthyl) benzidine, N, N'-diphenyl-N, N'-bis [4'-(diphenylamino) biphenyl-4 -Il] benzidine, 4-cyanobiphenyl, 4-cyano-4'-methylbiphenyl, 4-cyano-4'-ethylbiphenyl, 4-cyano-4'-propylbiphenyl, 4-cyano-4'-pentylbiphenyl, 4-Cyano-4'-hydroxybiphenyl, 4-cyano-4''-propyl-p-terphenyl, 4-cyano-4''-pentyl-p-terphenyl, 4-amino-p-terphenyl, 4 , 4''-diamino-p-terphenyl, 4-amino-2,6-diphenylphenol, 4-anilino-1,1': 4', 1''-terphenyl, 2'-fluoro-4-pentyl -4''-propyl-1,1': 4', 1''-terphenyl, 4,4'''-dihydroxy-p-quarterphenyl can be mentioned, and because of their excellent phase difference characteristics and transparency, N , N, N', N'-tetraphenylbenzidine, N, N'-diphenyl-N, N'-di (o-tolyl) benzidine, N, N'-diphenyl-N, N'-di (m-tolyl) ) Benzidine, N, N'-diphenyl-N, N'-di (p-tolyl) benzidine, N, N'-bis (4-formylphenyl) -N, N'-diphenylbenzidine, N, N'-di (4-Biphenylyl) -N, N'-diphenylbenzidine, N, N'-bis (4-methoxy-2-methylphenyl) -N, N'-diphenylbenzidine, 4-cyano-4''-propyl-p − Terphenyl, 4-Cyano-4''− Pentyl-p-terphenyl, 4-amino-p-terphenyl, 4,4 ″ -diamino-p-terphenyl, 4,4 ″-dihydroxy-p-quarterphenyl are preferred.

The resin composition of the present invention may contain an antioxidant in order to improve thermal stability. Antioxidants include, for example, hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, lactone-based antioxidants, amine-based antioxidants, hydroxylamine-based antioxidants, and vitamins. Examples thereof include E-based antioxidants and other antioxidants, 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-based light stabilizer or an ultraviolet absorber in order to enhance weather resistance. Examples of the ultraviolet absorber include benzotriazol, benzophenone, triazine, benzoate and the like.

The resin composition of the present invention contains other polymers, surfactants, polymer electrolytes, conductive complexes, pigments, dyes, antistatic agents, antiblocking agents, lubricants, etc., as long as the gist of the invention is not exceeded. May be.

The resin composition of the present invention can be obtained by blending a cellulosic resin, an ester resin exhibiting negative birefringence, and a polyphenyl compound (hereinafter referred to as a resin or the like).

As a blending method, a method such as melt blending or solution blending can be used. The melt blending method is a method of producing by melting a resin or the like by heating and kneading the resin or the like. The solution blending method is a method in which a resin or the like is dissolved in a solvent and blended. Examples of the solvent used for the solution blend include chlorine-based solvents such as methylene chloride and chloroform; aromatic solvents such as toluene and xylene; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Chloroform solvent such as propanol; ether solvent such as dioxane and tetrahydrofuran; dimethylformamide, N-methylpyrrolidone and the like can be used. It is also possible to dissolve the resin or the like in a solvent and then blend it, and it is also possible to knead the powder, pellets or the like of each resin and then dissolve it in the solvent. It is also possible to put the obtained blended resin solution into a poor solvent to precipitate the resin composition, and it is also possible to use the blended resin solution as it is for producing an optical compensation film.

The optical compensation film using the resin composition of the present invention preferably has a thickness of 5 to 200 μm, more preferably 10 to 100 μm, from the viewpoint of the handleability of the film and the compatibility of the optical member with thinning. 20 to 80 μm is particularly preferable, and 10 to 60 μm is most preferable.

The phase difference characteristics of the optical compensation film using the resin composition of the present invention differ depending on the target optical compensation film. For example, 1) the in-plane retardation (Re) represented by the following formula (a) is found. It is preferably 50 to 300 nm, more preferably 100 to 300 nm, particularly preferably 100 to 280 nm, and the Nz coefficient represented by the following formula (c) is preferably 0.30 to 1.00, still more preferably 0.35. ~ 0.65, particularly preferably 0.45 to 0.55, 2) The out-of-plane phase difference (Rth) represented by the following formula (b) is preferably −400 to 20 nm, more preferably −400 to −400. Examples thereof include those having a diameter of −100 nm, particularly preferably −400 to −200 nm. The phase difference characteristic at this time is measured using a fully automatic birefringence meter (manufactured by Oji Measuring Instruments Co., Ltd., trade name KOBRA-21ADH) under the condition of a measurement wavelength of 589 nm.

These have retardation characteristics that are difficult to develop with an optical compensation film made of a conventional cellulosic resin.

Re = (ny-nx) x D (a)
Rth = [(nx + ny) /2-nz] x D (b)
Nz = (ny-nz) / (ny-nx) (c)
(In the formula, nx indicates the refractive index in the phase-advancing axis direction in the film surface, ny indicates the refractive index in the slow-phase axial direction in the film surface, nz indicates the refractive index outside the film surface, and D indicates the film. Indicates the thickness.)
The wavelength dispersion characteristic of the optical film of the present invention is preferably 0.60 <Re (450) / Re (550) <1.05, more preferably 0.70 <Re (450), in order to suppress color shift. ) / Re (550) <1.02, and particularly preferably 0.75 <Re (450) / Re (550) <1.00.

When a cellulosic ether is used as the cellulosic resin of the present invention, it is possible to provide an optical film having a low wavelength dispersion by itself. A resin composition obtained by blending this film with an ester-based resin exhibiting negative birefringence with respect to the stretching direction can generally provide an optical film exhibiting reverse wavelength dispersibility.

Satisfying these retardation characteristics and wavelength dispersion characteristics at the same time is generally difficult to achieve with an optical compensation film using a cellulosic resin, but when a cellulosic ether is used in the present invention, it is difficult to achieve this. An optical compensation film using the resin composition according to the present invention satisfies these characteristics at the same time.

In order to reduce the required film thickness, the optical compensation film of the present invention has a ratio of retardation to film thickness at 589 nm Re (589) (nm) / film thickness (μm) of 4.0 nm / μm or more. Is preferable.

The optical compensation film of the present invention has a light transmittance of preferably 85% or more, more preferably 90% or more in order to improve the brightness.

The optical compensation film of the present invention has a haze of preferably 1% or less, more preferably 0.5% or less, in order to improve contrast.

Since the optical compensation film of the present invention preferably has a colorless hue, the yellowness YI is preferably 2 or less, more preferably 1 or less.

The haze of the optical compensation film of the present invention after 500 hours in an environment of 85 ° C. is preferably 3% or less, more preferably 1% or less, and particularly preferably 0.5% or less in order to improve contrast. Further, the yellowness YI after 500 hours in an environment of 85 ° C. is preferably 2 or less, more preferably 1 or less because the hue is preferably colorless.

As a method for producing an optical compensation film using the resin composition of the present invention, any method may be used as long as the optical compensation film of the present invention can be produced, but in terms of optical characteristics, heat resistance, surface characteristics, etc. Since an excellent optical compensation film can be obtained, it is preferably produced by the solution casting method. Here, the solution casting method is a method in which a resin solution (generally referred to as a dope) is cast on a support substrate and then heated to evaporate the solvent to obtain an optical compensation film. As a method of spreading, 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, and industrially , A method of continuously extruding a dope from a die onto a belt-shaped or drum-shaped support substrate is generally used. Further, examples of the support substrate used include a glass substrate, a metal substrate such as stainless steel and a ferrotype, and a plastic substrate such as polyethylene terephthalate. A metal substrate having a mirror-finished surface is preferably used for industrial continuous film formation of a substrate having highly excellent surface properties and optical homogeneity. In the solution casting method, the viscosity of the resin solution is an extremely important factor when producing an optical compensation film having excellent thickness accuracy and surface smoothness, and the viscosity of the resin solution is the concentration of the resin, the molecular weight, and the type of solvent. It depends on.

The resin solution for producing an optical compensation film using the resin composition of the present invention is prepared by dissolving a cellulosic resin, an ester resin exhibiting negative birefringence, and a polyphenyl compound in a solvent. The viscosity of the resin solution can be adjusted by adjusting 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 facilitate film coatability.

As a method for producing an optical compensation film using the resin composition of the present invention, for example, the cellulosic resin represented by the general formula (1) as a resin component is 29.99 to 98.9% by weight and negative birefringence. It contains 1 to 70% by weight of an ester resin exhibiting properties, and further, a polyphenyl compound is dissolved in a solvent, the obtained resin solution is cast on a base material, dried, and then peeled off from the base material. ..

The optical compensation film obtained by using the resin composition of the present invention is preferably uniaxially stretched or unbalanced biaxially stretched in order to exhibit an in-plane retardation (Re). As a method for stretching the optical compensation film, a longitudinal uniaxial stretching method by roll stretching, a horizontal uniaxial stretching method by tenter stretching, an unbalanced sequential biaxial stretching method by a combination of these, an unbalanced simultaneous biaxial stretching method, etc. are used. Can be used. Further, in the present invention, the phase difference characteristic can be exhibited without using a special stretching method in which stretching is performed under the action of the shrinking force of the heat-shrinkable film.

The thickness of the optical compensation film at the time of stretching is preferably 10 to 200 μm, more preferably 15 to 150 μm, and particularly preferably 15 to 100 μm from the viewpoint of ease of stretching treatment and compatibility with 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 phase difference characteristics can be obtained. The draw ratio of uniaxial stretching is not particularly limited, but 1.05 to 4.0 times is preferable, and 1.1 to 3.5 times is more preferable, because good retardation characteristics can be obtained. The draw ratio of unbalanced biaxial stretching is not particularly limited, but 1.05 to 4.0 times is preferable in the length direction, and 1.1 to 3.5 times, because the optical compensation film has excellent optical characteristics. The magnification is more preferable, and the optical compensation film having excellent optical characteristics is obtained. Therefore, 1.01 to 1.2 times is preferable in the width direction, and 1.05 to 1.1 times is further preferable. The in-plane phase difference (Re) can be controlled by the stretching temperature and the stretching ratio.

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

The optical compensation film using the resin composition of the present invention can be used as a λ / 4 plate or a λ / 2 plate.

Further, the optical compensation film using the resin composition of the present invention can be used as a circularly polarizing film in combination with a polarizing plate.

The optical compensation film using the resin composition of the present invention exhibits specific retardation characteristics and specific wavelength dispersion characteristics in a thin film, and is excellent in transparency and hue stability at high temperatures. Therefore, optics for liquid crystal displays. It is useful as a compensation film and an antireflection film.

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.

<Polymer analysis>
^{The structural analysis of the polymer was determined by proton nuclear magnetic resonance spectroscopy (1} H-NMR) spectral analysis using a nuclear magnetic resonance measuring device (manufactured by JEOL Ltd., trade name: JNM-GX270).

^{1 When the} composition ratio analysis was difficult from the H-NMR spectrum analysis, the fumaric acid monoester concentration was determined according to the JIS K 2501 (2003 version) petroleum product and lubricating oil-neutralization value test method.

<Measurement of number average molecular weight>
Gel Pas - Mieishon chromatography - (GPC) apparatus (Tosoh - trade name: C0-8011 (fitted with a column _GMH HR -H)) using tetrahydrofuran or dimethylformamide as solvent, measured at 40 ° C. Then, it was calculated as a standard polystyrene conversion value.

<Measurement of light transmittance and haze of optical compensation film>
For the light transmittance and haze of the produced film, use a haze meter (manufactured by Nippon Denshoku Industries, Ltd., trade name: NDH2000), and the light transmittance is JIS K 7361-1 (1997 version). , Haze was measured according to JIS-K 7136 (2000 version).

<Measurement of yellowness YI of optical compensation film>
The yellowness YI of the produced film was measured using a spectrocolorimeter (manufactured by Nippon Denshoku Industries, Ltd., trade name: SD-5000) in accordance with JIS-K 7373.

<Measurement of phase difference characteristics>
The phase difference characteristic of the optical compensation film was measured using light having a wavelength of 589 nm using a sample tilt type automatic birefringence meter (manufactured by Oji Measuring Instruments, trade name: KOBRA-WR).

<Measurement of wavelength dispersion characteristics>
Using a sample tilt type automatic birefringence meter (manufactured by Oji Measuring Instruments, trade name: KOBRA-WR), the ratio of the phase difference Re (450) due to light with a wavelength of 450 nm and the phase difference Re (550) due to light with a wavelength of 550 nm is optical. The wavelength dispersion characteristics of the compensation film were measured.

<Measurement of heat resistance>
Using a gear oven (manufactured by Toyo Seiki Seisakusho, trade name: STD60P) (replacement rate 3 times / min) in a high temperature environment of 85 ° C., the haze and YI after 500 hours are examined (hereinafter referred to as "heat durability test"). ), The heat resistance was measured.

Synthesis Example 1 (Synthesis of ester resin showing negative birefringence (diisopropyl fumarate / monoethyl fumarate) 1)
42 g of diisopropyl fumarate, 7.7 g of monoethyl fumarate and 0.66 g of tert-butylperoxypivalate as a polymerization initiator were placed in a glass ampoule having a capacity of 75 mL, and after repeating nitrogen substitution and depressurization, the mixture was melted under reduced pressure. did. This ampoule was placed in a constant temperature bath at 55 ° C. and held for 24 hours for radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was added dropwise to 4 L of hexane to precipitate, and then vacuum dried at 80 ° C. for 10 hours to obtain 27 g of a diisopropyl fumarate / monoethyl fumarate resin. The number average molecular weight of the obtained resin was 53,000, the diisopropyl fumarate residue unit was 82 mol%, and the monoethyl fumarate residue unit was 18 mol%.

Synthesis Example 2 (Synthesis of ester resin showing negative birefringence (monoethyl fumarate / diisopropyl fumarate / n-propyl 4-methoxycinnamate) 2)
In a glass ampoule with a capacity of 75 mL, 6.7 g of monoethyl fumarate, 37 g of diisopropyl fumarate, 6.1 g of n-propyl 4-methoxycinnamate and 2,5-dimethyl-2,5-di (2-di) as a polymerization initiator 1.48 g of ethylhexanoylperoxy) hexane 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 60 ° C. and held for 48 hours for radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 50 g of tetrahydrofuran. This polymer solution was added dropwise to methanol / water = 70/30 (% by weight / wt%) to precipitate, washed with methanol / water = 70/30 (% by weight / wt%) 2 kg, and then at 80 ° C. for 10 hours. By vacuum drying, 26 g of monoethyl fumarate / diisopropyl fumarate / n-propyl 4-methoxysilicate dermatate was obtained. The number average molecular weight of the obtained resin was 32,000, monoethyl fumarate residue unit 15 mol%, diisopropyl fumarate residue unit 72 mol%, and n-propyl fumarate n-propyl residue unit 13 mol%. It was.

Synthesis Example 3 (Synthesis of ester resin showing negative birefringence (monoethyl fumarate / diisopropyl fumarate / n-propyl 4-methoxycinnamate) 3)
In a glass ampoule with a capacity of 75 mL, 1.6 g of monoethyl fumarate, 4.8 g of diisopropyl fumarate, 44 g of n-propyl 4-methoxycinnamate and 2,5-dimethyl-2,5-di (2-), which is a polymerization initiator. 1.18 g of ethylhexanoylperoxy) hexane 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 60 ° C. and held for 60 hours for radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved in 50 g of tetrahydrofuran. This polymer solution was dropped into hexane to precipitate, washed with 2 kg of hexane, and then vacuum dried at 80 ° C. for 10 hours to obtain 11 g of monoethyl fumarate / diisopropyl fumarate / n-propyl 4-methoxysilicate resin. Got The number average molecular weight of the obtained resin was 36,000, monoethyl fumarate residue unit 7 mol%, diisopropyl fumarate residue unit 11 mol%, and n-propyl fumarate n-propyl residue unit 82 mol%. It was.

Example 1
Ethyl cellulose as a cellulosic resin (ETHOCEL standard 100 manufactured by Dow Chemical Co., Ltd., molecular weight Mn = 55,000, molecular weight Mw = 176,000, Mw / Mn = 3.2, total substitution degree DS = 2.5) 75 g, 75 g of diisopropyl fumarate / monoethyl fumarate resin obtained in Synthesis Example 1, and 7.89 g of N, N'-diphenyl-N, N'-di (m-tolyl) benzidine were added to toluene / acetone = 8 /. Dissolve in 2 (weight ratio) solution to make an 18% by weight resin solution, spill it on a polyethylene terephthalate film with a coater, dry it in two stages at 140 ° C after a drying temperature of 60 ° C, and then optical compensation film with a width of 150 mm. (Resin composition) was obtained (cellulosic resin: 47.5% by weight, ester resin exhibiting negative compound refractive property: 47.5% by weight, polyphenyl compound: 5% by weight). The obtained optical compensation film was cut into a 50 mm square and uniaxially stretched 2.0 times at a predetermined stretching temperature (thickness after stretching: 30 μm).

The light transmittance, haze, YI, retardation characteristics, and wavelength dispersion characteristics of the stretched optical compensation film were measured. In addition, the haze and YI after the thermal durability test were measured. The results are shown in Table 1.

The haze and YI of the obtained film after the thermal durability test were small and had high heat resistance. Moreover, each optical characteristic was suitable as an optical compensation film.

Example 2
7.89 g of N, N'-bis (4-methoxy-2-methylphenyl) -N, N'-diphenylbenzidine instead of N, N'-diphenyl-N, N'-di (m-tolyl) benzidine An optical compensation film (resin composition) was obtained in the same manner as in Example 1 except that it was used (cellulose resin: 47.5% by weight, ester resin exhibiting negative birefractive property: 47.5% by weight). %, Polyphenyl compound: 5% by weight).

The light transmittance, haze, YI, retardation characteristics, and wavelength dispersion characteristics of the stretched optical compensation film were measured. In addition, the haze and YI after the thermal durability test were measured. The results are shown in Table 1.

The haze and YI of the obtained film after the thermal durability test were small and had high heat resistance. Moreover, each optical characteristic was suitable as an optical compensation film.

Example 3
Same as in Example 1 except that 7.89 g of 4-cyano-4''-pentyl-p-terphenyl was used instead of N, N'-diphenyl-N, N'-di (m-tolyl) benzidine. An optical compensation film (resin composition) was obtained (cellulosic resin: 47.5% by weight, ester resin exhibiting negative birefringence: 47.5% by weight, polyphenyl compound: 5% by weight). ..

The light transmittance, haze, YI, retardation characteristics, and wavelength dispersion characteristics of the stretched optical compensation film were measured. In addition, the haze and YI after the thermal durability test were measured. The results are shown in Table 1.

The haze and YI of the obtained film after the thermal durability test were small and had high heat resistance. Moreover, each optical characteristic was suitable as an optical compensation film.

Example 4
75 g of ethyl cellulose used in Example 1, 75 g of monoethyl fumarate / diisopropyl fumarate / n-propyl 4-methoxysilicate resin obtained in Synthesis Example 2, and 4,4'''-dihydroxy-p-quarter. 3.06 g of phenyl is dissolved in a toluene / acetone = 8/2 (weight ratio) solution to make an 18% by weight resin solution, which is spilled onto a polyethylene terephthalate film with a coater, and dried at 60 ° C. and then at 140 ° C. for 2 After step-drying, an optical compensation film (resin composition) having a width of 150 mm was obtained (cellulose resin: 49% by weight, ester resin exhibiting negative compound refractive property: 49% by weight, polyphenyl compound: 2% by weight). ). The obtained optical compensation film was cut into a 50 mm square and uniaxially stretched 2.0 times at a predetermined stretching temperature (thickness after stretching: 30 μm).

The light transmittance, haze, YI, retardation characteristics, and wavelength dispersion characteristics of the stretched optical compensation film were measured. In addition, the haze and YI after the thermal durability test were measured. The results are shown in Table 1.

The haze and YI of the obtained film after the thermal durability test were small and had high heat resistance. Moreover, each optical characteristic was suitable as an optical compensation film.

Example 5
An optical compensation film (resin composition) was prepared in the same manner as in Example 4 except that 7.89 g of 4-amino-p-terphenyl was used instead of 4,4'''-dihydroxy-p-quarterphenyl. Obtained (cellulosic resin: 47.5% by weight, ester resin exhibiting negative birefringence: 47.5% by weight, polyphenyl compound: 5% by weight).

The light transmittance, haze, YI, retardation characteristics, and wavelength dispersion characteristics of the stretched optical compensation film were measured. In addition, the haze and YI after the thermal durability test were measured. The results are shown in Table 1.

The haze and YI of the obtained film after the thermal durability test were small and had high heat resistance. Moreover, each optical characteristic was suitable as an optical compensation film.

Example 6
88.4 g of ethyl cellulose used in Example 1, 61.6 g of monoethyl fumarate / diisopropyl fumarate / n-propyl 4-methoxysilicate resin obtained in Synthesis Example 3, and 4-cyano-4''-. 7.89 g of pentyl-p-terphenyl is dissolved in a toluene / acetone = 8/2 (weight ratio) solution to obtain an 18% by weight resin solution, which is then poured onto a polyethylene terephthalate film by a coater and after a drying temperature of 60 ° C. After two-stage drying at 140 ° C., an optical compensation film (resin composition) having a width of 150 mm was obtained (cellulose resin: 56% by weight, ester resin exhibiting negative compound refractive property: 39% by weight, polyphenyl). Compound: 5% by weight). The obtained optical compensation film was cut into a 50 mm square and uniaxially stretched 2.0 times at a predetermined stretching temperature (thickness after stretching: 30 μm).

The light transmittance, haze, YI, retardation characteristics, and wavelength dispersion characteristics of the stretched optical compensation film were measured. In addition, the haze and YI after the thermal durability test were measured. The results are shown in Table 1.

The haze and YI of the obtained film after the thermal durability test were small and had high heat resistance. Moreover, each optical characteristic was suitable as an optical compensation film.

Example 7
Same as in Example 6 except that 16.67 g of N, N'-diphenyl-N, N'-di (m-tolyl) benzidine was used instead of 4-cyano-4''-pentyl-p-terphenyl. An optical compensation film (resin composition) was obtained (cellulosic resin: 53% by weight, ester resin exhibiting negative birefringence: 37% by weight, polyphenyl compound: 10% by weight).

The light transmittance, haze, YI, retardation characteristics, and wavelength dispersion characteristics of the stretched optical compensation film were measured. In addition, the haze and YI after the thermal durability test were measured. The results are shown in Table 1.

The haze and YI of the obtained film after the thermal durability test were small and had high heat resistance. Moreover, each optical characteristic was suitable as an optical compensation film.

Comparative Example 1
88.5 g of ethyl cellulose used in Example 1 and 61.5 g of monoethyl fumarate / diisopropyl fumarate / n-propyl 4-methoxysilicate dermatate obtained in Synthesis Example 3 were added to toluene / acetone = 8/2 (weight). Ratio) Dissolve in a solution to make an 18% by weight resin solution, sprinkle it on a polyethylene terephthalate film with a coater, dry it in two stages at 140 ° C after a drying temperature of 60 ° C, and then optical compensation film with a width of 150 mm (resin composition) (Cellulose-based resin: 59% by weight, ester-based resin exhibiting negative compound refractive property: 41% by weight). The obtained optical compensation film was cut into a 50 mm square and uniaxially stretched 2.0 times at a predetermined stretching temperature (thickness after stretching: 30 μm).

The light transmittance, haze, YI, retardation characteristics, and wavelength dispersion characteristics of the stretched optical compensation film were measured. In addition, the haze and YI after the thermal durability test were measured. The results are shown in Table 1.

The YI of the obtained film after the thermal durability test was large and the heat resistance was low.

Claims (8)

Cellulose having a structural unit represented by the following general formula (1) - scan ether 29.99 to 98.99 wt% and, fumarate residue unit represented by the following general formula (8), and / or the following general formula It contains 1 to 70% by weight of an ester-based resin exhibiting negative birefractive properties containing the cinnamic acid ester residue unit shown in (9), and further contains 0.01 to 30% by weight of a polyphenyl compound. A resin composition characterized by.

(In the formula, R _{1 to} R ₃ independently represent hydrogen or a substituent having 1 to 12 carbon atoms.)

(In the formula, R ₁₆ and R ₁₇ each independently represent hydrogen or an alkyl group having 1 to 12 carbon atoms.)

(In the formula, R ₁₈ represents hydrogen or an alkyl group having 1 to 12 carbon atoms. R ₁₉ is a hydrogen, nitro group, bromo group, iodo group, cyano group, chloro group, sulfonic acid group, carboxylic acid group, fluoro group. , A phenyl group or an alkoxy group having 1 to 12 carbon atoms.) The resin composition according to claim 1, wherein the polyphenyl compound is a polyphenyl compound containing at least one selected from the group consisting of polyphenyl structures represented by the following general formulas (2) to (7). Stuff.

(In the formula, X ₁ and X ₂ are independently represented by the following general formula (X), where m = 1 to 6).

(In the formula, R ₄ and R ₅ independently represent a benzene ring, a naphthalene ring or a fluorene ring, respectively, and are substituted with a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group or a phenyl group, respectively. May be.)

(In the formula, R ₆ represents a benzene ring, a naphthalene ring or a fluorene ring, and may be substituted with a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group or a phenyl group. A ₁ , A ₂ is independently represented by a hydrogen, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group, a phenyl group or the general formula (X), where m = 1 to 6. )

(In the formula, A _{3 to} A ₅ are independently represented by hydrogen, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an acyloxy group, an alkoxy group, a phenyl group or the general formula (X), where m. = 1-6.)

(In the formula, R _{7 to} R ₉ are independently hydrogen, hydroxy group, nitro group, bromo group, iodo group, cyano group, chloro group, sulfonic acid group, carboxylic acid group, fluoro group and 1 to 1 carbon atoms. It shows 12 alkyl groups, acyloxy groups, or alkoxy groups, where n = 0-4.)

(In the formula, R _{10 to} R ₁₂ are independently hydrogen, hydroxy group, nitro group, bromo group, iodo group, cyano group, chloro group, sulfonic acid group, carboxylic acid group, fluoro group and 1 to 1 carbon atoms. It shows 12 alkyl groups, acyloxy groups, or alkoxy groups, where n = 0-4.)

(In the formula, R _{13 to} R ₁₅ are independently hydrogen, hydroxy group, nitro group, bromo group, iodo group, cyano group, chloro group, sulfonic acid group, carboxylic acid group, fluoro group and 1 to 1 carbon atoms. It shows 12 alkyl groups, acyloxy groups, or alkoxy groups, where n = 0-4.) The resin composition according to claim 2, wherein the polyphenyl compound is formed with a polyphenyl structure represented by the general formula (2). The polyphenyl compound is formed of the polyphenyl structure represented by the general formula (5), and R _{7 to} R ₉ are hydrogen, a hydroxy group, a cyano group, a carboxylic acid group, an alkyl group having 1 to 12 carbon atoms, and the like. The resin composition according to claim 2, wherein the resin composition is an acyloxy group or an alkoxy group. The resin composition according to any one of claims 1 to 4 is used, the in-plane phase difference (Re) represented by the following formula (a) is 0 to 20 nm, and the following formula (b) is used. An optical compensation film characterized in that the indicated out-of-plane phase difference (Rth) is −400 to 20 nm.
Re = (ny-nx) x D (a)
Rth = [(nx + ny) /2-nz] x D (b)
(In the formula, nx indicates the refractive index in the phase-advancing axis direction in the film surface, ny indicates the refractive index in the slow-phase axial direction in the film surface, nz indicates the refractive index outside the film surface, and D indicates the film. Indicates the thickness.) Using the resin composition according to any one of claims 1 to 4, in-plane retardation represented by the following formula (a) (Re) is 50 to 300 nm, the in-plane retardation at a wavelength of 450nm of light The ratio Re (450) / Re (550) of the in-plane phase difference (Re) at 550 nm is 0.60 to 1.05, and the Nz coefficient represented by the following formula (c) is 0. An optical compensation film characterized by being 3 to 1.0.
Re = (ny-nx) x D (a)
Nz = (ny-nz) / (ny-nx) (c)
(In the formula, nx indicates the refractive index in the phase-advancing axis direction in the film surface, ny indicates the refractive index in the slow-phase axial direction in the film surface, nz indicates the refractive index outside the film surface, and D indicates the film. Indicates the thickness.) The optical compensation film according to claim 5 or 6 , wherein the haze is 3% or less and the yellowness YI is 2 or less after 500 hours in an environment of 85 ° C. The resin composition according to any one of claims 1 to 4 is dissolved in a solvent to obtain a resin solution, the resin solution is cast on a base material, dried, and then peeled off from the base material. The method for producing an optical compensation film according to any one of claims 5 to 7.