JP2023152307A - Resin composition and optical film using the same - Google Patents

Abstract

To provide: a resin composition suitable for optical films; an optical film having excellent phase difference characteristics using the same; and a method for producing the optical film.SOLUTION: This invention relates to: a resin composition comprising, as a resin component, 70 to 97 wt.% of a cellulose ester resin represented by the general formula (1), and 3 to 30 wt.% of a fumarate-based polymer containing 80 to 95 mol% of a specific fumarate residue unit and 2 to 20% mol% of a specific cinnamate residue unit; an optical film using the resin composition; and a method for producing the optical film. (In the formula, R1, R2, and R3 each independently represent hydrogen or a C2-4 acyl group).SELECTED DRAWING: None

Description

The present invention relates to a resin composition and an optical film using the same, and more particularly to a resin composition and an optical film for liquid crystal displays having excellent retardation characteristics.

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

There are many types of liquid crystal displays, such as vertical alignment type (VA-LCD), in-plane alignment type liquid crystal display (IPS-LCD), super twisted nematic type liquid crystal display (STN-LCD), reflective type liquid crystal display, and transflective type liquid crystal display. There are various methods, and an optical compensation film that matches the display is required.

Stretched films of cellulose resin, polycarbonate, cyclic polyolefin, and the like are used as conventional optical compensation films. In particular, films made of cellulose resins such as triacetylcellulose films are widely used because they have good adhesion to polyvinyl alcohol, which is a polarizer.

Among cellulose resins, cellulose ester resins are widely used as optical compensation films, but there are no materials with large negative intrinsic birefringence that can be blended with cellulose ester resins to obtain transparent films. There was an issue. (For example, see Patent Document 1) Furthermore, since the material having negative intrinsic birefringence described in Patent Document 1 has a positive glass region photoelastic coefficient due to its structure, a blend film with cellulose ester has a large positive glass region. There was a problem in developing a photoelastic coefficient.

Special WO2020/162259

The present invention has been made in view of the above problems, and its purpose is to provide a resin composition suitable for optical films, particularly optical compensation films, and an optical film using the same that has excellent retardation characteristics.

As a result of intensive studies to solve the above problems, the present inventors have discovered a resin composition containing a specific cellulose ester resin and a specific fumarate ester polymer, an optical film using the same, and a method for producing the same. However, they have found a solution to the above problems and have completed the present invention. That is, the present invention contains 70 to 97% by weight of a cellulose ester resin represented by general formula (1), 80 to 95 mol% of fumarate ester residue units represented by general formula (2), and the following general formula ( 3) A resin composition characterized by containing 3 to 30% by weight of a fumaric acid ester polymer containing 5 to 20 mol% of cinnamate ester residue units, an optical film using the same, and This is the manufacturing method.

The present invention will be explained in detail below.

The resin composition of the present invention comprises, as resin components, 70 to 97% by weight of a cellulose ester resin represented by the following general formula (1), 80 to 95 mol% of fumarate ester residue units represented by the following general formula (2), and Contains 3 to 30% by weight of a fumaric acid ester polymer containing 5 to 20 mol% of cinnamate ester residue units represented by the following general formula (3).

(In the formula, R ₁ , R ₂ and R ₃ each independently represent hydrogen or an acyl group having 2 to 4 carbon atoms.)

(In the formula, R ₄ and R ₅ independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms.)

(In the formula, R ₆ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and X represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms.)
Since the cellulose ester resin of the present invention has excellent mechanical properties and excellent moldability during film formation, it is possible to prepare a 10% solution dissolved in methylene chloride/methanol (9/1 weight ratio) at 25°C. The viscosity is preferably 150 to 10,000 mPa·s, more preferably 300 to 8,000 mPa·s, particularly preferably 500 to 5,000 mPa·s.

The degree of substitution (DS) in which cellulose hydroxyl groups are substituted via oxygen atoms in the cellulose ester resin of the present invention is the ratio (100 % esterification means DS=3), and from the viewpoint of solubility, compatibility, and stretching processability, the total degree of substitution DS of ester groups is preferably 2.3 to 3.0, more preferably It is 2.4 to 3.0, particularly preferably 2.7 to 3.0, and two or more different cellulose ester resins may be used in combination.

R ₁ , R ₂ , and R ₃ in the cellulose ester resin are each independently hydrogen or an acyl group having 2 to 4 carbon atoms, and examples of the acyl group having 2 to 4 carbon atoms include an acetyl group, a propionyl group, Examples include butyroyl groups.

Specific cellulose ester resins in the present invention include cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and the like. Among these, cellulose acetate and cellulose acetate propionate are preferred, and cellulose acetate is particularly preferred because of their excellent optical properties. Moreover, you may contain two or more types of cellulose ester resins.

The fumaric acid ester polymer contained in the resin composition of the present invention includes 80 to 95 mol% of fumaric acid ester residue units represented by the general formula (2) and a cinnamate ester polymer represented by the general formula (3). It contains 5 to 20 mol% of residue units. When the fumarate ester residue unit is less than 80 mol % and when the silicate ester residue unit is more than 20 mol %, a transparent optical film cannot be obtained.

R ₄ and R ₅ , which are ester substituents of the fumarate residue unit in the fumarate ester polymer, are independently hydrogen or an alkyl group having 1 to 8 carbon atoms, and as an alkyl group having 1 to 8 carbon atoms, For example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, 2-ethylhexyl group can be mentioned. Specific fumarate ester residue units include monomethyl fumarate residue unit, monoethyl fumarate residue unit, monopropyl fumarate residue unit, monoisopropyl fumarate residue unit, monobutyl fumarate residue unit, and fumarate monobutyl residue unit. Acid monoisobutyl residue unit, fumarate mono sec-butyl residue unit, fumarate mono tert-butyl residue unit, fumarate monopentyl residue unit, fumarate monoheptyl residue unit, fumarate monohexyl residue unit, fumarate Acid monocyclohexyl residue unit, monooctyl fumarate residue unit, mono 2-ethylhexyl fumarate residue unit, dimethyl fumarate residue unit, diethyl fumarate residue unit, dipropyl fumarate residue unit, diisopropyl fumarate residue unit group unit, dibutyl fumarate residue unit, diisobutyl fumarate residue unit, disec-butyl fumarate residue unit, di-tert-butyl fumarate residue unit, dipentyl fumarate residue unit, dihexyl fumarate residue unit , dicyclohexyl fumarate residue unit, diheptyl fumarate residue unit, dioctyl fumarate residue unit, di(2-ethylhexyl) fumarate residue unit, ethyl isopropyl fumarate residue unit, ethyl tert-butyl fumarate residue units, ethylcyclohexyl fumarate residue units, isopropyl tert-butyl fumarate residue units, isopropylcyclohexyl fumarate residue units, tert-butylcyclohexyl fumarate residue units, etc., and one of these or Two or more types may be used. Among them, monoethyl fumarate residue units, monoisopropyl fumarate residue units, monobutyl fumarate residue units, diisopropyl fumarate residue units, diisopropyl fumarate residue units, and Sec-butyl residue units, di-tert-butyl fumarate residue units, and dicyclohexyl fumarate residue units are preferred, and diisopropyl fumarate residue units are particularly preferred.

R ₆ , which is an ester substituent of the silicate ester residue unit in the fumarate ester polymer, represents an alkyl group having 1 to 8 carbon atoms, and examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, etc. group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, and 2-ethylhexyl group. Further, the aromatic cyclic substituent X of the silicate ester residue unit in the fumarate ester polymer represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, such as hydrogen, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, teat-butyl group, methoxy group, ethoxy group, propoxy group, and isopropoxy group. Specific examples of silicate ester residue units include methyl cinnamate residue units, ethyl cinnamate residue units, propyl cinnamate residue units, isopropyl cinnamate residue units, and butyl cinnamate residue units. base unit, cinnamate sec-butyl residue unit, cinnamate tert-butyl residue unit, cinnamate isobutyl residue unit, cinnamate pentyl residue unit, cinnamate hexyl residue unit, cinnamic acid cyclohexyl residue unit, heptyl cinnamate residue unit, octyl cinnamate residue unit, 2-ethylhexyl cinnamate residue unit, p-methylcinnamate residue unit, p-methylcinnamate methyl residue unit, Ethyl p-methylcinnamate residue unit, propyl p-methylcinnamate residue unit, isopropyl p-methylcinnamate residue unit, butyl p-methylcinnamate residue unit, sec-butyl p-methylcinnamate residue unit, p-methylcinnamate tert-butyl residue unit, p-methylcinnamate isobutyl residue unit, p-methylcinnamate pentyl residue unit, p-methylcinnamate hexyl residue unit, p-methylcinnamate cyclohexyl unit residue unit, heptyl p-methylcinnamate residue unit, octyl p-methylcinnamate residue unit, 2-ethylhexyl p-methylcinnamate residue unit, methyl p-ethylcinnamate residue unit, p-ethylcinnamate acid ethyl cinnamate residue unit, p-ethyl cinnamate propyl residue unit, p-ethyl cinnamate isopropyl residue unit, p-ethyl cinnamate butyl residue unit, p-ethyl cinnamate sec-butyl residue unit, p- tert-butyl ethylcinnamate residue unit, isobutyl p-ethylcinnamate residue unit, pentyl p-ethylcinnamate residue unit, hexyl p-ethylcinnamate residue unit, cyclohexyl p-ethylcinnamate residue unit, Heptyl p-ethylcinnamate residue unit, octyl p-ethylcinnamate residue unit, 2-ethylhexyl p-ethylcinnamate residue unit, methyl p-propylcinnamate residue unit, ethyl p-propylcinnamate residue unit, p-propylcinnamate propyl residue unit, p-propylcinnamate isopropyl residue unit, p-propylcinnamate butyl residue unit, p-propylcinnamate sec-butyl residue unit, p-propyl cinnamate tert-butyl residue unit, p-propyl cinnamate isobutyl residue unit, p-propyl cinnamate pentyl residue unit, p-propyl cinnamate hexyl residue unit, p-propyl cinnamate Cyclohexyl cinnamate residue unit, p-propylcinnamate heptyl residue unit, p-propylcinnamate octyl residue unit, p-propylcinnamate 2-ethylhexyl residue unit, p-methoxycinnamate methyl residue group unit, p-methoxycinnamate ethyl residue unit, p-methoxycinnamate propyl residue unit, p-methoxycinnamate isopropyl residue unit, p-methoxycinnamate butyl residue unit, p-methoxy sec-butyl cinnamate residue unit, tert-butyl p-methoxycinnamate residue unit, isobutyl p-methoxycinnamate residue unit, pentyl p-methoxycinnamate residue unit, p-methoxycinnamate Acid hexyl residue unit, p-methoxycinnamate cyclohexyl residue unit, p-methoxycinnamate heptyl residue unit, p-methoxycinnamate octyl residue unit, p-methoxycinnamate 2-ethylhexyl residue unit, p-ethoxycinnamate methyl residue unit, p-ethoxycinnamate ethyl residue unit, p-ethoxycinnamate propyl residue unit, p-ethoxycinnamate isopropyl residue unit, p-ethoxycinnamate butyl residue unit unit, p-ethoxycinnamate sec-butyl residue unit, p-ethoxycinnamate tert-butyl residue unit, p-ethoxycinnamate isobutyl residue unit, p-ethoxycinnamate pentyl residue unit, p-ethoxycinnamate Acid hexyl residue unit, p-ethoxycinnamate cyclohexyl residue unit, p-ethoxycinnamate heptyl residue unit, p-ethoxycinnamate octyl residue unit, p-ethoxycinnamate 2-ethylhexyl residue unit, p- Methyl propoxycinnamate residue unit, ethyl p-propoxycinnamate residue unit, propyl p-propoxycinnamate residue unit, isopropyl p-propoxycinnamate residue unit, butyl p-propoxycinnamate residue group unit, p-propoxycinnamate sec-butyl residue unit, p-propoxycinnamate tert-butyl residue unit, p-propoxycinnamate isobutyl residue unit, p-propoxycinnamate pentyl residue unit , p-propoxycinnamate hexyl residue unit, p-propoxycinnamate cyclohexyl residue unit, p-propoxycinnamate heptyl residue unit, p-propoxycinnamate octyl residue unit, p-propoxycinnamate Examples include acid 2-ethylhexyl residue units, and one or more of these may be used. Among these, ethyl cinnamate residue units, isopropyl cinnamate residue units, butyl cinnamate residue units, isobutyl cinnamate residue units, p-ethyl methyl cinnamate residue unit, isopropyl p-methyl cinnamate residue unit, butyl p-methyl cinnamate residue unit, isobutyl p-methyl cinnamate residue unit, ethyl p-methoxycinnamate residue unit, p -Methoxycinnamate isopropyl residue unit, p-methoxycinnamate butyl residue unit, p-methoxycinnamate isobutyl residue unit, p-propoxycinnamate 2-ethylhexyl residue unit are preferable, p-methoxycinnamate isopropyl residue unit, Particularly preferred are ethyl cinnamate residue units and p-methoxypropyl cinnamate residue units.

The fumarate ester polymer contains a fumarate ester residue unit and a cinnamate ester residue unit and a residue unit of another monomer that can be copolymerized with the fumarate ester residue unit. Examples of the residue units of other monomers that can be copolymerized with fumarate ester residue units and cinnamate ester residue units include styrene residue units and α-methylstyrene residue units. Styrene residue units such as; acrylic acid residue units; acrylic ester residue units such as methyl acrylate residue units, ethyl acrylate residue units, and butyl acrylate residue units; methacrylic acid residue units; Methacrylate ester residue units such as methyl methacrylate residue unit, ethyl methacrylate residue unit, butyl methacrylate residue unit; vinyl ester residue units such as vinyl acetate residue unit and vinyl propionate residue unit Vinyl ether residue units such as methyl vinyl ether residue unit, ethyl vinyl ether residue unit, butyl vinyl ether residue unit; N-methyl maleimide residue unit, N-cyclohexyl maleimide residue unit, N-phenyl maleimide residue unit, etc. N-substituted maleimide residue unit; acrylonitrile residue unit; methacrylonitrile residue unit; olefin residue unit such as ethylene residue unit, propylene residue unit; vinylpyrrolidone residue unit; vinylpyridine residue unit, etc. One or more types can be mentioned.

The fumaric acid ester polymer must have a number average molecular weight (Mn) of 1×10 ³ to 5×10 ⁵ in terms of standard polystyrene obtained from an elution curve measured by gel permeation chromatography (GPC). is preferable, and more preferably 2×10 ³ to 3×10 ⁵ , and more preferably 5×10 ³ to 2×10 ⁵ because it has excellent mechanical properties and excellent moldability during film formation. It is particularly preferable that

The composition ratio of the cellulose ester resin and the fumaric acid ester polymer in the resin composition of the present invention is 70 to 97% by weight of the cellulose ester resin and 3 to 50% by weight of the fumaric acid ester polymer. When the content of cellulose ester resin is less than 70% by weight, it becomes difficult to control transparency. Furthermore, if the content of the cellulose ester resin exceeds 97% by weight, it is difficult to control the glass region photoelastic coefficient. Preferably 73 to 97% by weight of cellulose ester resin and 3 to 27% by weight of fumaric acid ester polymer, more preferably 80 to 97% by weight of cellulose ester resin and 3 to 20% by weight of fumaric acid ester polymer. %.

The fumaric acid ester polymer may be produced by any method as long as the fumaric acid ester polymer can be obtained. For example, fumaric acid ester and cinnamate ester, or fumaric acid It can be produced by radical polymerization using esters and cinnamate esters together with other copolymerizable monomers. Other monomers copolymerizable with fumaric acid esters and cinnamic acid esters include, for example, styrenes such as styrene and α-methylstyrene; acrylic acid; methyl acrylate, ethyl acrylate, acrylic Acrylic acid esters such as butyl methacrylate; Methacrylic acid; Methacrylic esters such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate; Vinyl esters such as vinyl acetate and vinyl propionate; Acrylonitrile; Methacrylonitrile; Ethylene; Examples include one or more of olefins such as propylene; vinylpyrrolidone; and vinylpyridine.

As the method of radical polymerization, for example, any of the bulk polymerization method, solution polymerization method, suspension polymerization method, precipitation polymerization method, emulsion polymerization method, etc. can be adopted.

Examples of polymerization initiators used in radical polymerization include benzoyl peroxide, lauryl peroxide, octanoyl peroxide, acetyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide. Organic peroxides such as 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-butyronitrile), 2,2'-azobisisobutyronitrile, dimethyl-2 , 2'-azobisisobutyrate, and 1,1'-azobis(cyclohexane-1-carbonitrile).

There are no particular restrictions on the solvents that can be used in the solution polymerization method or precipitation polymerization method; examples include aromatic solvents such as benzene, toluene, and xylene; alcoholic solvents such as methanol, ethanol, propyl alcohol, and butyl alcohol; cyclohexane, Examples include dioxane, tetrahydrofuran, acetone, methyl ethyl ketone, dimethyl formamide, isopropyl acetate, and mixed solvents thereof.

Furthermore, the polymerization temperature during radical polymerization can be appropriately set depending on the decomposition temperature of the polymerization initiator, and is generally preferably carried out in the range of 30 to 150°C.

The resin composition of the present invention may contain an antioxidant in order to improve thermal stability. Examples of antioxidants include hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, lactone-based antioxidants, amine-based antioxidants, hydroxylamine-based antioxidants, and vitamin E-based antioxidants. Antioxidants and other antioxidants may be mentioned, and these antioxidants may be used alone or in combination of two or more.

The resin composition of the present invention may contain a hindered amine light stabilizer and an ultraviolet absorber to improve weather resistance. Examples of the ultraviolet absorber include benzotriazole, benzophenone, triazine, and benzoate.

A compound known as a so-called plasticizer may be added to the resin composition of the present invention for the purpose of improving mechanical properties, imparting flexibility, imparting water absorption resistance, reducing water vapor transmission rate, adjusting retardation, etc. Examples of the plasticizer include phosphoric acid esters, carboxylic acid esters, sugar esters, and the like. Acrylic polymers are also used. Examples of the phosphoric acid ester include triphenyl phosphate, tricresyl phosphate, and phenyl diphenyl phosphate. Examples of carboxylic esters include phthalic esters, citric esters, and adipic esters. Examples of phthalic esters include dimethyl phthalate, diethyl phthalate, dicyclohexyl phthalate, dioctyl phthalate, and diethylhexyl phthalate, and adipic esters. Examples of the ester include bis(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, and (2-butoxyethyl) adipate, and examples of the citric acid ester include acetyltriethyl citrate and acetyl citrate. Examples include tributyl. Other examples include butyl oleate, methylacetyl ricinoleate, dibutyl sebatate, triacetin, trimethylolpropane tribenzoate, and the like. Examples of sugar esters include sucrose octabenzoate, sucrose octaacetate, and sucrose acetate isobutyrate. Alkylphthalyl alkyl glycolates are also used for this purpose. The alkyl in the alkylphthalyl alkyl glycolate is an alkyl group having 1 to 8 carbon atoms. Examples of alkylphthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butylphthalyl butyl glycolate, octylphthalyl octyl glycolate, and methyl phthalyl ethyl glycolate. , ethylphthalyl methyl glycolate, ethylphthalyl propyl glycolate, propyl phthalyl ethyl glycolate, methyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethylphthalyl butyl glycolate, butylphthalyl methyl glycolate, Butylphthalyl ethyl glycolate, propylphthalyl butyl glycolate, butylphthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octylphthalyl methyl glycolate, octylphthalyl ethyl glycolate, etc. I can list them. Two or more of these plasticizers may be used in combination.

The resin composition of the present invention may contain an additive having an aromatic hydrocarbon ring or an aromatic heterocycle for the purpose of adjusting the phase difference. There is no particular restriction on the birefringence Δn shown by the following formula (A) of the additive used for the purpose of adjusting the phase difference, but
In order to obtain an optical film with excellent optical properties, it is preferably 0.05 or more, more preferably 0.05 to 0.5, particularly preferably 0.1 to 0.5. Δn of the additive can be determined by molecular orbital calculation.

Δn=ny-nx (A)
(In the formula, nx represents the refractive index in the fast axis direction of the additive molecule, and ny represents the refractive index in the slow axis direction of the additive molecule.)
When the resin composition of the present invention contains an additive having an aromatic hydrocarbon ring or an aromatic heterocycle, the additive having an aromatic hydrocarbon ring or an aromatic heterocycle in the resin composition of the present invention The number of aromatic hydrocarbon rings or aromatic heterocycles in the molecule is not particularly limited, but it is preferably 1 to 12, and more preferably 1 to 12, since it provides an optical film with excellent optical properties. is 1 to 8. Examples of the aromatic hydrocarbon ring include a 5-membered ring, a 6-membered ring, a 7-membered ring, and a condensed ring consisting of two or more aromatic rings. Examples of the aromatic heterocycle include a furan ring, etc. , thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring, 1,3,5-triazine ring and the like.

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

Examples of the additive having an aromatic hydrocarbon ring or aromatic heterocycle used in the present invention include tricresyl phosphate, tricylenyl phosphate, triphenyl phosphate, 2-ethylhexyl diphenyl phosphate, cresyl diphenyl phosphate, Phosphate ester compounds such as bisphenol A bis(diphenyl phosphate); dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, di-n-octyl phthalate, 2-ethylhexyl phthalate, diisooctyl phthalate, dicapryl phthalate, dinonyl phthalate, diisononyl Phthalate ester compounds such as phthalate, didecyl phthalate, diisodecyl phthalate; tributyl trimellitate, tri-n-hexyl trimellitate, tri(2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, tri-isoctyl trimellitate Trimelitate, tri-isodecyl trimellitate and other trimellitic acid ester compounds; tri(2-ethylhexyl)pyromellitate, tetrabutylpyromellitate, tetra-n-hexylpyromellitate, tetra(2-ethylhexyl)pyromellitate, tetra - Pyromellitic acid ester compounds such as normal octyl pyromellitate, tetra-isoctyl pyromellitate, and tetra-isodecyl pyromellitate; benzoic acid ester compounds such as ethyl benzoate, isopropyl benzoate, and ethyl paraoxybenzoate Salicylic acid ester compounds such as phenyl salicylate, p-octylphenyl salicylate, and p-tert-butylphenyl salicylate; Glycolic acid ester compounds such as methyl phthalylethyl glycolate, ethyl phthalyl ethyl glycolate, and butylphthalyl butyl glycolate Compounds; benzotriazole compounds such as 2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole and 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole ;2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxy Benzophenone compounds such as -5-sulfobenzophenone, sulfonamide compounds such as N-benzenesulfonamide, 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl)-1,3,5- Examples include triazine compounds such as triazine, 2,4-diphenyl-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, and preferably tricresyl phosphate, 2-ethylhexyldiphenyl phosphate, 2 -hydroxy-4-methoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, etc., and these can be used alone or in combination of two or more as necessary.

When the resin composition of the present invention contains an additive having an aromatic hydrocarbon ring or an aromatic heterocycle, from the viewpoint of optical properties and mechanical properties, aromatic carbonization in the resin composition of the present invention is preferable. The proportion of the additive having a hydrogen ring or aromatic heterocycle is 0 to 30% by weight, more preferably 0 to 20% by weight, particularly preferably 0 to 15% by weight.

The resin composition of the present invention may contain other polymers, surfactants, polymer electrolytes, conductive complexes, pigments, dyes, antistatic agents, antiblocking agents, lubricants, etc. within the scope of the gist of the invention. It's okay.

The resin composition of the present invention can be obtained by blending a cellulose ester resin and a fumaric acid ester polymer.

As the blending method, methods such as melt blending and solution blending can be used. The melt blending method is a manufacturing method in which resins are melted by heating and kneaded. The solution blending method is a method in which resin is dissolved in a solvent and blended. The solvent used in the solution blending method is not limited as long as it dissolves the resin, but chlorinated solvents such as methylene chloride and chloroform are preferably used. Further, mixed solvents in which alcohols such as methanol, ethanol, and butanol are added to these chlorinated solvents are preferably used.

In the present invention, an optical film using the resin composition of the present invention and having a thickness of 15 to 200 μm can be produced.

A film using the resin composition of the present invention has a thickness of 15 to 200 μm, preferably 18 to 150 μm, and particularly preferably 20 to 100 μm, from the viewpoint of film handling properties.

The glass band photoelastic coefficient (Cg) of the optical film using the resin composition of the present invention is preferably less than 10×10 ⁻¹² Pa ⁻¹ , more preferably It is less than 9×10 ⁻¹² Pa ⁻¹ , particularly preferably less than 8×10 ⁻¹² Pa ⁻¹ . The glass region photoelastic coefficient at this time is determined by measuring the amount of change in the in-plane retardation (Re) using a fully automatic birefringence meter (manufactured by Axometrics, product name: AxoScan) under conditions where the tensile load of the film is changed. It is calculated by measurement.

The optical film using the resin composition of the present invention preferably has a thickness of 5 to 100 μm, more preferably 10 to 150 μm, from the viewpoint of ease of handling the film and suitability for thinning of optical members. ~100 μm is particularly preferred.

The retardation characteristics of the optical film using the resin composition of the present invention are such that the ratio of the in-plane retardation (Re) to the film thickness (d) expressed by the following formula (1) is 1 nm/μm from the viewpoint of thinning the film. It is preferable that it is above. The phase difference characteristic at this time is measured using a fully automatic birefringence meter (manufactured by Axometrics, trade name: AxoScan) at a measurement wavelength of 589 nm.

Re=(ny-nx)×d (1)
(In the formula, nx indicates the refractive index in the fast axis direction (the direction with the smallest refractive index) in the film plane, and ny indicates the refractive index in the slow axis direction (the direction with the largest refractive index) in the film plane. nz indicates the refractive index outside the film plane, and d indicates the film thickness.)
In order to improve brightness, the optical film of the present invention preferably has a light transmittance of 85% or more, more preferably 90% or more.

In order to improve contrast, the optical film of the present invention preferably has a haze of 1% or less, more preferably 0.8% or less, and even more preferably 0.6% or less.

As a method for producing an optical film using the resin composition of the present invention, any method may be used as long as the optical film of the present invention can be produced. Since a film can be obtained, it is preferable to manufacture by a solution casting method. Here, the solution casting method is a method in which a resin solution (generally referred to as a dope) is cast onto a support substrate, and then the solvent is evaporated by heating to obtain an optical film. Examples of casting methods used include the T-die method, doctor blade method, bar coater method, roll coater method, and lip coater method. A method of continuously extruding is generally used. Examples of supporting substrates that can be used include glass substrates, metal substrates such as stainless steel and ferrotype substrates, and plastic substrates such as polyethylene terephthalate. In order to industrially continuously form a substrate with highly excellent surface properties and optical homogeneity, a metal substrate with a mirror-finished surface is preferably used. In the solution casting method, the viscosity of the resin solution is an extremely important factor when producing optical films with excellent thickness accuracy and surface smoothness, and the viscosity of the resin solution depends on the concentration of the resin, molecular weight, and type of solvent. It depends.

A resin solution for producing an optical film using the resin composition of the present invention is prepared by dissolving a cellulose ester resin and a fumaric acid ester polymer 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 in order to facilitate film coating, it is preferably 100 to 10,000 mPa·s, more preferably 300 to 5,000 mPa·s, particularly preferably 500 to 3,000 mPa·s. be.

The method for producing an optical film using the resin composition of the present invention includes, for example, 70 to 97% by weight of a cellulose ester resin represented by the above general formula (1) and a fumarate represented by the above general formula (2) as resin components. A resin containing 3 to 30% by weight of a fumaric acid ester polymer containing 80 to 95 mol% of acid ester residue units and 5 to 20 mol% of cinnamate ester residue units represented by the above general formula (3). An example of this method is to dissolve the composition in a solvent, cast the resulting resin solution on a base material, and peel it off from the base material after drying.

The optical film obtained using the resin composition of the present invention is preferably stretched in order to improve the in-plane retardation (Re). As a method for stretching the optical film, a longitudinal uniaxial stretching method using roll stretching, a horizontal uniaxial stretching method using tenter stretching, an unbalanced sequential biaxial stretching method or an unbalanced simultaneous biaxial stretching method using a combination thereof, etc. can be used. . Further, in the present invention, retardation characteristics can be developed without using a special stretching method in which stretching is performed under the action of the shrinkage force of a heat-shrinkable film.

The thickness of the optical film during stretching is preferably 15 to 200 μm, more preferably 18 to 150 μm, from the viewpoint of ease of stretching treatment and suitability for thinning of optical members. , 20 to 100 μm is particularly preferred.

The stretching temperature is not particularly limited, but is preferably 50 to 210°C, more preferably 80 to 200°C, particularly preferably 100 to 190°C, since good retardation properties can be obtained. The stretching ratio for uniaxial stretching is not particularly limited, but it is preferably 1.05 to 2.5 times, more preferably 1.1 to 2.2 times, and 1.0 to 2.5 times, more preferably 1.1 to 2.2 times, since good and uniform retardation characteristics can be obtained. .2 to 2.0 times is particularly preferred. There is no particular restriction on the stretching ratio for unbalanced biaxial stretching, but it is preferably 1.05 to 2.5 times in the length direction, and 1.1 to 2.2 times, since it results in an optical film with excellent optical properties. is more preferably 1.2 to 2.0 times, particularly preferably 1.2 to 2.0 times, and 1.01 to 1.2 times is preferable in the width direction, and 1.05 to 1.1 times, since this results in an optical film with excellent optical properties. It is more preferable to double the amount. The in-plane retardation (Re) can be controlled by the stretching temperature and stretching ratio.

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

Since the optical film using the resin composition of the present invention is a thin film and exhibits specific retardation characteristics, it is useful as an optical compensation film for liquid crystal displays and the like.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

In addition, the various 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) spectroscopy using a nuclear magnetic resonance analyzer (manufactured by JEOL, trade name: JNM-GX270).

<Measurement of number average molecular weight>
Measured at 40°C using a gel permeation chromatography (GPC) device (manufactured by Tosoh, product name: HLC-8320GPC (equipped with column GMH _HR -H)), using tetrahydrofuran as a solvent, and calculating the standard polystyrene equivalent value. I asked for it as.

<Measurement of solution viscosity>
Measurement was performed at 25° C. using a B-type viscometer (manufactured by BROOKFIELD, trade name: DV2T).

<Measurement of film light transmittance and haze>
The light transmittance and haze of the produced film were measured using a haze meter (manufactured by Nippon Denshoku Kogyo, product name: NDH2000). Measurements were made in accordance with JIS-K 7136 (2000 edition).

<Measurement of photoelastic coefficient>
It was determined by using a fully automatic birefringence meter (manufactured by Axometrics, trade name AxoScan) and a sample tensioning jig to change the tensile load on the film and measure the change in retardation of the film using light with a wavelength of 589 nm.

<Measurement of phase difference characteristics>
The retardation characteristics of the optical film were measured using a fully automatic birefringence meter (manufactured by Axometrics, trade name AxoScan) using light with a wavelength of 589 nm.

Synthesis example 1
61.4 g of diisopropyl fumarate, 8.6 g of ethyl 4-methoxycinnamate, and 0.51 g of tert-butylperoxypivalate as a polymerization initiator were placed in a glass ampoule with a capacity of 100 mL, and nitrogen purging and depressurization were repeated. Afterwards, it was melted under reduced pressure. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80° C. for 10 hours to obtain 50 g of diisopropyl fumarate/ethyl 4-methoxycinnamate copolymer. The number average molecular weight of the obtained polymer was 75,000, 88 mol% of diisopropyl fumarate residue units, and 12 mol% of ethyl 4-methoxycinnamate residue units.

Synthesis example 2
58.2 g of diisopropyl fumarate, 3.1 g of monoethyl fumarate, 8.7 g of ethyl 4-methoxycinnamate, and 0.52 g of tert-butylperoxypivalate as a polymerization initiator were placed in a 100 mL glass ampoule, and the mixture was heated with nitrogen. After repeating displacement and depressurization, it was melted under reduced pressure. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80°C for 10 hours to obtain 46 g of diisopropyl fumarate/monoethyl fumarate/ethyl 4-methoxycinnamate copolymer. . The number average molecular weight of the obtained polymer was 49,000, and diisopropyl fumarate residue units were 78 mol%, monoethyl fumarate residue units were 9 mol%, and 4-methoxycinnamate ethyl residue units were 13 mol%. .

Synthesis example 3
58.2 g of diisopropyl fumarate, 6.2 g of ethyl cinnamate, and 0.51 g of tert-butyl peroxypivalate as a polymerization initiator were placed in a 100 mL glass ampoule, and after repeated nitrogen purging and depressurization, the pressure was reduced. It was melted. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80° C. for 10 hours to obtain 33 g of diisopropyl fumarate/ethyl cinnamate copolymer. The number average molecular weight of the obtained polymer was 30,000, 88 mol% of diisopropyl fumarate residue units, and 12 mol% of ethyl cinnamate residue units.

Synthesis example 4
66.2 g of diisopropyl fumarate, 3.8 g of propyl 4-methoxycinnamate, and 0.51 g of tert-butylperoxypivalate as a polymerization initiator were placed in a 100 mL glass ampoule, and nitrogen purging and depressurization were repeated. Afterwards, it was melted under reduced pressure. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80° C. for 10 hours to obtain 62 g of diisopropyl fumarate/ethyl cinnamate copolymer. The number average molecular weight of the obtained polymer was 128,000, 94 mol% of diisopropyl fumarate residue units, and 6 mol% of ethyl cinnamate residue units.

Synthesis example 5
54.4 g of diisopropyl fumarate, 5.3 g of monoethyl fumarate, 10.3 g of ethyl cinnamate, and 0.53 g of tert-butyl peroxypivalate as a polymerization initiator were placed in a 100 mL glass ampoule, and the mixture was replaced with nitrogen and degassed. After repeating the pressure, it was melted under reduced pressure. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80° C. for 10 hours to obtain 25 g of diisopropyl fumarate/monoethyl fumarate/ethyl cinnamate copolymer. The number average molecular weight of the obtained polymer was 37,000, 73 mol% of diisopropyl fumarate residue units, 11 mol% of monoethyl fumarate residue units, and 16 mol% of ethyl cinnamate residue units.

Synthesis example 6
In a glass ampoule with a capacity of 100 mL, 48.9 g of diisopropyl fumarate, 11.1 g of di(2-ethylhexyl fumarate), 10.0 g of ethyl 4-methoxycinnamate, and 0.0 g of tert-butyl peroxypivalate, which is a polymerization initiator, were added. 47 g was put in, and after repeating nitrogen substitution and depressurization, it was melted under reduced pressure. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80°C for 10 hours to form a diisopropyl fumarate/di(2-ethylhexyl) fumarate/ethyl 4-methoxycinnamate copolymer. A total of 43 g was obtained. The number average molecular weight of the obtained polymer was 38,000, 79 mol% of diisopropyl fumarate residue units, 5 mol% of monoethyl fumarate residue units, and 16 mol% of ethyl cinnamate residue units.

Synthesis example 7
51.0 g of diisopropyl fumarate, 19.0 g of 2-ethylhexyl 4-methoxycinnamate, and 0.47 g of tert-butylperoxypivalate as a polymerization initiator were placed in a 100 mL glass ampoule, and the mixture was purged with nitrogen and depressurized. After repeating this process, it was melted under reduced pressure. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80° C. for 10 hours to obtain 32 g of diisopropyl fumarate/2-ethylhexyl 4-methoxycinnamate copolymer. The number average molecular weight of the obtained polymer was 42,000, 82 mol% of diisopropyl fumarate residue units, and 18 mol% of 2-ethylhexyl 4-methoxycinnamate residue units.

Synthesis example 8
63.3 g of diisopropyl fumarate, 6.7 g of ethyl 4-methylcinnamate, and 0.51 g of tert-butyl peroxypivalate as a polymerization initiator were placed in a 100 mL glass ampoule, and after repeated nitrogen purging and depressurization. It was melted under reduced pressure. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80° C. for 10 hours to obtain 39 g of diisopropyl fumarate/ethyl 4-methylcinnamate copolymer. The number average molecular weight of the obtained polymer was 35,000, 89 mol% of diisopropyl fumarate residue units, and 11 mol% of ethyl 4-methylcinnamate residue units.

Synthesis example 9
68.1 g of diisopropyl fumarate, 1.8 g of ethyl cinnamate, and 0.51 g of tert-butyl peroxypivalate as a polymerization initiator were placed in a 100 mL glass ampoule, and after repeated nitrogen substitution and depressurization, the pressure was reduced. It was melted. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80° C. for 10 hours to obtain 64 g of diisopropyl fumarate/ethyl cinnamate copolymer. The number average molecular weight of the obtained polymer was 108,000, 97 mol% of diisopropyl fumarate residue units, and 3 mol% of ethyl cinnamate residue units.

Synthesis example 10
55.7 g of diisopropyl fumarate, 14.3 g of ethyl 4-methoxycinnamate, and 0.51 g of tert-butylperoxypivalate as a polymerization initiator were placed in a glass ampoule with a capacity of 100 mL, and nitrogen substitution and depressurization were repeated. Afterwards, it was melted under reduced pressure. This ampoule was placed in a constant temperature bath at 50° C. and maintained for 72 hours to carry out radical polymerization. After the polymerization reaction was completed, the polymer was taken out from the ampoule and dissolved in 200 g of tetrahydrofuran. This polymer solution was dropped into 4 L of hexane to precipitate, and then vacuum-dried at 80° C. for 10 hours to obtain 59 g of diisopropyl fumarate/ethyl 4-methoxycinnamate copolymer. The number average molecular weight of the obtained polymer was 44,000, 79 mol% of diisopropyl fumarate residue units, and 21 mol% of ethyl cinnamate residue units.

Example 1
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.36. 0g, and 4.0g of the diisopropyl fumarate/ethyl 4-methoxycinnamate copolymer obtained in Synthesis Example 1 were dissolved in methylene chloride:methanol = 95:5 (weight ratio) to make a 15% by weight resin solution. The mixture was coated onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass region photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 2
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.32. 0 g, 4.0 g of diisopropyl fumarate/monoethyl fumarate/ethyl 4-methoxycinnamate copolymer obtained in Synthesis Example 2, and 4.0 g of sucrose octaacetate were mixed in methylene chloride:methanol = 95:5 (weight ratio) A 15% by weight resin solution was obtained by dissolving the resin solution, which was poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then dried at 100°C for 20 minutes, and further dried at 120°C for 5 minutes to obtain a width of 150 mm. An optical film was obtained. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass region photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 3
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.30. 0g, and 10.0g of the diisopropyl fumarate/ethyl cinnamate copolymer obtained in Synthesis Example 3 were dissolved in methylene chloride:methanol = 95:5 (weight ratio) to make a 15% by weight resin solution, and the mixture was coated with a coater. The mixture was poured onto a polyethylene terephthalate film and dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass region photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 4
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.34. 0 g, and 6.0 g of the diisopropyl fumarate/4-methoxypropyl cinnamate copolymer obtained in Synthesis Example 4 were dissolved in methylene chloride:methanol = 95:5 (weight ratio) to obtain a 15% by weight resin solution. The mixture was coated onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 5
As a cellulose ester resin, cellulose acetate (cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9)28. 0 g, 10.0 g of the diisopropyl fumarate/monoethyl fumarate/ethyl cinnamate copolymer obtained in Synthesis Example 5, and 2.0 g of sucrose octabenzoate were dissolved in methylene chloride:methanol = 95:5 (weight ratio). A 15% by weight resin solution was formed, which was poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to form an optical film with a width of 150 mm. I got it. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 6
As a cellulose ester resin, cellulose acetate (cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9)38. 0g, 4.0g of diisopropyl fumarate/bis(2-ethylhexyl) fumarate/ethyl 4-methoxycinnamate copolymer obtained in Synthesis Example 6, and 2.0g of 2-ethylhexyl adipate in methylene chloride:methanol= The resin solution was dissolved at a ratio of 95:5 (weight ratio) to make a 15% by weight resin solution, poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and further at 120°C. After drying for 5 minutes, an optical film with a width of 150 mm was obtained. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 7
As a cellulose ester resin, cellulose acetate (cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9)38. 0g, 2.0g of the diisopropyl fumarate/2-ethylhexyl 4-methoxycinnamate copolymer obtained in Synthesis Example 7 was dissolved in methylene chloride:methanol = 95:5 (weight ratio) to obtain a 15% by weight resin. The solution was formed into a solution, poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 8
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.36. 0 g, and 4.0 g of the diisopropyl fumarate/4-methyl ethyl cinnamate copolymer obtained in Synthesis Example 8 were dissolved in methylene chloride:methanol = 95:5 (weight ratio) to make a 15% by weight resin solution. It was dripped onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then dried at 100°C for 20 minutes, and further dried at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 9
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.32. 0g, 4.0g of diisopropyl fumarate/ethyl 4-methylcinnamate copolymer obtained in Synthesis Example 1 and 4.0g of sucrose octaacetate as a plasticizer were dissolved in methylene chloride:methanol = 95:5 (weight ratio). The resulting 15% by weight resin solution was poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes. Got the film. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 10
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.32. 0 g, 4.0 g of the diisopropyl fumarate/monoethyl fumarate/4-methyl ethyl cinnamate copolymer obtained in Synthesis Example 2, and 4.0 g of bis(2-ethylhexyl) adipate as a plasticizer in methylene chloride:methanol= The resin solution was dissolved at a ratio of 95:5 (weight ratio) to make a 15% by weight resin solution, poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and further at 120°C. After drying for 5 minutes, an optical film with a width of 150 mm was obtained. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass region photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 11
Cellulose acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., cellulose acetate, 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 700 mPa・s, total substitution degree DS = 2.4) 38.4 g as cellulose ester resin , 1.6 g of the diisopropyl fumarate/monoethyl fumarate/4-methyl ethyl cinnamate copolymer obtained in Synthesis Example 2 was dissolved in methylene chloride:methanol = 95:5 (weight ratio) to obtain a 15% by weight resin. The solution was formed into a solution, poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Example 12
Cellulose acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., cellulose acetate, 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 700 mPa・s, total substitution degree DS = 2.4) 37.2 g as cellulose ester resin , 2.8 g of the diisopropyl fumarate/monoethyl fumarate/4-methyl ethyl cinnamate copolymer obtained in Synthesis Example 2 was dissolved in methylene chloride:methanol = 95:5 (weight ratio) to obtain a 15% by weight resin. The solution was formed into a solution, poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film had desired optical properties including haze, total light transmittance, and glass region photoelastic coefficient (Cg).

Comparative example 1
As a cellulose ester resin, 40 g of cellulose acetate (cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa・s, total substitution degree DS = 2.9) was used. It was dissolved in methylene chloride:methanol = 95:5 (weight ratio) to make a 15% by weight resin solution, poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, and then at 100°C for 20 minutes. The film was further dried at 120° C. for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film did not have the desired optical properties in terms of glass region photoelastic coefficient.

Comparative example 2
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.26. 0g, and 14.0g of the diisopropyl fumarate/ethyl 4-methoxycinnamate copolymer obtained in Synthesis Example 1 were dissolved in methylene chloride:methanol = 95:5 (weight ratio) to obtain a 15% by weight resin solution. The mixture was coated onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass area photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film did not have the desired optical properties due to haze.

Comparative example 3
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.36. 0g, and 4.0g of the diisopropyl fumarate/ethyl cinnamate copolymer obtained in Synthesis Example 9 were dissolved in methylene chloride:methanol = 95:5 (weight ratio) to make a 15% by weight resin solution, and the mixture was coated with a coater. The mixture was poured onto a polyethylene terephthalate film and dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass region photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film did not have the desired optical properties due to haze.

Comparative example 4
Cellulose acetate (Cellulose triacetate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 1500 mPa·s, total substitution degree DS = 2.9) as a cellulose ester resin.36. 0g, and 4.0g of the diisopropyl fumarate/ethyl 4-methoxycinnamate copolymer obtained in Synthesis Example 10 were dissolved in methylene chloride:methanol = 95:5 (weight ratio) to obtain a 15% by weight resin solution. The mixture was coated onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze and total light transmittance were measured. The results are shown in Table 1.

The obtained optical film did not have the desired optical properties due to haze.

Comparative example 5
Cellulose acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., cellulose acetate, 10% methylene chloride/methanol (9/1 weight ratio) solution viscosity: 700 mPa・s, total substitution degree DS = 2.4) 39.2 g as a cellulose ester resin , 0.8 g of the diisopropyl fumarate/monoethyl fumarate/4-methyl ethyl cinnamate copolymer obtained in Synthesis Example 2 was dissolved in methylene chloride:methanol = 95:5 (weight ratio) to obtain a 15% by weight resin. The solution was formed into a solution, poured onto a polyethylene terephthalate film using a coater, dried at 40°C for 5 minutes, then at 100°C for 20 minutes, and then at 120°C for 5 minutes to obtain an optical film with a width of 150 mm. The obtained optical film was cut into a size of 15 mm x 60 mm, and the haze, total light transmittance, and glass region photoelastic coefficient were measured. The results are shown in Table 1.

The obtained optical film did not have the desired optical properties in terms of glass region photoelastic coefficient.

Example 13
The optical film obtained in Example 1 was cut out to a size of 30 mm x 50 mm, and uniaxially stretched to 1.6 times at 170°C.

The retardation characteristics of the obtained optical film were measured. The results are shown in Table 2.

The obtained optical film had the desired optical properties in terms of the absolute value of the glass region photoelastic coefficient, in-plane retardation (Re), and out-of-plane retardation (Rth).

Example 14
The optical film obtained in Example 2 was cut out to a size of 30 mm x 50 mm, and uniaxially stretched 2.0 times at 190°C.

The retardation characteristics of the obtained optical film were measured. The results are shown in Table 2.

The obtained optical film had the desired optical properties in terms of the absolute value of the glass region photoelastic coefficient, in-plane retardation (Re), and out-of-plane retardation (Rth).

Example 15
The optical film obtained in Example 3 was cut out to a size of 30 mm x 50 mm, and uniaxially stretched to 3.0 times at 195°C.

The retardation characteristics of the obtained optical film were measured. The results are shown in Table 2.

The obtained optical film had the desired optical properties in terms of the absolute value of the glass region photoelastic coefficient, in-plane retardation (Re), and out-of-plane retardation (Rth).

Example 16
The optical film obtained in Example 5 was cut out to a size of 30 mm x 50 mm, and uniaxially stretched to 2.0 times at 195°C.

The retardation characteristics of the obtained optical film were measured. The results are shown in Table 2.

The obtained optical film had the desired optical properties in terms of the absolute value of the glass region photoelastic coefficient, in-plane retardation (Re), and out-of-plane retardation (Rth).

Comparative example 6
The optical film obtained in Comparative Example 1 was cut out to a size of 30 mm x 50 mm, and uniaxially stretched to 2.0 times at 200°C.

The retardation characteristics of the obtained optical film were measured. The results are shown in Table 2.

The obtained optical film did not have the desired optical properties in terms of the absolute value of the glass region photoelastic coefficient, in-plane retardation (Re), and out-of-plane retardation (Rth).

Claims (9)

As a resin component, 70 to 97% by weight of a cellulose ester resin represented by the following general formula (1), 80 to 95 mol% of fumarate ester residue units represented by the following general formula (2), and the following general formula (3) A resin composition characterized by containing 3 to 30% by weight of a fumarate ester polymer containing 5 to 20 mol% of cinnamate ester residue units.
(In the formula, R ₁ , R ₂ and R ₃ each independently represent hydrogen or an acyl group having 2 to 4 carbon atoms.)
(In the formula, R ₄ and R ₅ independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms.)
(In the formula, R ₆ represents an alkyl group having 1 to 8 carbon atoms, and X represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms.) 2. The resin composition according to claim 1, wherein the cellulose ester resin represented by general formula (1) is cellulose acetate or cellulose acetate propionate. An optical film comprising the resin composition according to claim 1 and having a thickness of 15 to 200 μm. The optical film according to claim 3, wherein the absolute value of the glass region photoelastic coefficient is less than 10×10 ⁻¹² Pa ⁻¹ . The optical film according to claim 3 or 4, having a light transmittance of 85% or more. The optical film according to claim 3 or 4, having a haze of 1% or less. The ratio of the in-plane retardation (Re) shown by the following formula (1) to the film thickness (d) is 1 nm/μm or more, and the ratio of the in-plane retardation (Rth) and the film thickness (d) shown by the following formula (2) is 1 nm/μm or more. The optical film according to claim 3 or 4, wherein the ratio of d) is -0.5 nm/μm or less.
Re=(ny-nx)×d (1)
Rth=(nz-(nx+ny)/2)×d
(In the formula, nx indicates the refractive index in the fast axis direction within the film plane, ny indicates the refractive index in the slow axis direction within the film plane, and nz indicates the refractive index outside the film plane.) 70 to 97% by weight of cellulose ester resin represented by general formula (1), 80 to 95 mol% of fumarate ester residue units represented by general formula (2), and cinnamate ester represented by general formula (3) A resin composition containing 3 to 30% by weight of a fumaric acid ester polymer containing 5 to 20 mol% of residual units is dissolved in a solvent, the resulting resin solution is cast onto a base material, and after drying, the base material is The method for producing an optical film according to claim 3 or 4, wherein the optical film is peeled from the material. 9. The method for producing an optical film according to claim 8, wherein the film having a thickness of 20 to 200 μm obtained by casting is uniaxially stretched or unbalanced biaxially stretched.