JPH06123807A - Cellulose ester film - Google Patents

Abstract

PURPOSE:To provide a polarizing plate having excellent wear resistance and chemical resistance by applying a UV-curing compsn. contg. a cation polymn. initiator on this film, then irradiating the coating with active energy rays, thereby providing a cured coating film. CONSTITUTION:The compd. contg. at least two epoxy groups which are constituting components of the energy ray curing compsn., refers to an epoxy resin which polymerizes to a high-molecular substance makes a crosslinking reaction by irradiation with energy rays in the presence of the cation polymn. initiator activated by the active energy rays. Such epoxy resin is exemplified by an arom. epoxy resin, alicyclic epoxy resin and aliphat. epoxy resin. The alicyclic epoxy resin is more preferable in terms of a curing property. These resins are usable in combination in order to obtain necessary performance. The more preferable form is combination use of 20 to 80 pts.wt., more preferably 40 to 60 pts.wt. alicyclic epoxy resin and 80 to 20 pts.wt., more preferably 60 to 40 pts.wt. >=1 kinds of either the arom. epoxy resin or the aliphat. epoxy resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cellulose ester film. More specifically, in applications requiring optical performance, for example, cellulose ester film widely used in polarizing plates of liquid crystal display devices, abrasion resistance and chemical resistance for durability of itself and protection of liquid crystal substances. And a cellulose ester film having anti-glare properties.

[0002]

BACKGROUND OF THE INVENTION Cellulose ester films, especially cellulose triacetate films, are widely used for optical applications such as polarizing plates because they are excellent in transparency and can easily form a film having small anisotropy in refractive index.

A polarizing plate excellent in abrasion resistance, chemical resistance and antiglare property is obtained by improving and using the above film as a protective film for a polarizing plate which is attached to an iodine and / or dichroic dye type polarizing film. Various attempts have been made to make the.

When a liquid crystal display is constructed by using such a polarizing plate, an extra protective plate or protective film for the polarizing plate is unnecessary, and a lightweight, thin and highly visible display can be obtained.

Liquid crystal displays are being widely used for various displays such as calculators, watches, pocket TVs, personal computers, and in-vehicle instruments. As the screens become larger, the display bodies become thinner and lighter. It has become an important goal of development along with commercialization and colorization.

In a conventional liquid crystal display, since a normal polarizing plate has poor wear resistance and chemical resistance, a glass or transparent plastic plate should be provided on the outermost surface of the display screen to protect the polarizing plate. did not become.

Therefore, a molded polarizing plate, that is, a polarizing film and a transparent plastic film such as cellulose triacetate bonded to each other are bonded to a polyester acrylate resin, (meth) acrylic acid ester resin, acrylic urethane resin, etc. A utility model 54-13044 has been published to devise a device to add a wear resistance and chemical resistance by providing a cured coating film with
Although it has been made in JP-A-1-105738 and the like, this method has a drawback in that a protective material is required and the polarizing plate itself becomes thick or heavy.

Further, in the published utility model 54-130441, a method for improving the wear resistance by vapor deposition of SiO ₂ , silicone-based apsite, phenol resin, etc. is proposed. However, in view of surface hardness and adhesiveness of plastic substrate Is still not enough.

Japanese Unexamined Patent Publication (Kokai) No. 1-105738 proposes a method for improving abrasion resistance and chemical resistance by providing a cured coating film made of an ultraviolet curing epoxy acrylate resin on one surface of an unsaponified triacetate film. However, if the cured film is thickened to increase the surface hardness, cracks such as cracks are likely to occur, and if it is exposed to an atmosphere of high temperature and high humidity because it cannot be saponified, the adhesion with the polarizing plate deteriorates. There are drawbacks such as

In addition, in order to exert high reliability and durability in various environments in the use of the polarizing plate, strong adhesion is required between the polarizing film and the protective film. As a method of improving this adhesiveness, in the case of the cellulose triacetate film which is most widely used as a protective film, the surface is saponified in advance with an alkaline solution, and then laminated with a polyvinyl alcohol adhesive or the like to obtain a polarizing film. . However, since the alkali treatment uses a high-concentration alkali solution, it is not preferable in terms of work safety and environmental protection, and further alkali treatment may lead to deterioration of quality such as bleed-out of plasticizer and increase in haze. is there.

Also, before the alkali treatment, antistatic treatment,
When the processing for imparting functionality such as hard coat processing is performed, the effect thereof is diminished by the alkali treatment, so that there is a problem that the functionalization of the protective film is limited after the alkali treatment.

[0012]

OBJECTS OF THE INVENTION Accordingly, the objects of the present invention are: 1) First, to provide a cellulose ester film for a protective film of a polarizing plate, which is excellent in abrasion resistance and chemical resistance. 2) Secondly, as a film support. Providing a cellulose ester film for a protective film of a polarizing plate having excellent adhesion 3) Third, providing a cellulose ester film for a protective film of a polarizing plate having excellent flexibility 4) Fourth, a polarizing film To provide a protective film for a polarizing plate, which has excellent adhesiveness and does not deteriorate in UV absorption ability or be colored even when exposed to severe conditions under high temperature and high humidity for a long time 5) 5 is to provide a cellulose ester film having a reduced cost by omitting the saponification treatment step. Other objects will be apparent from the following specification.

[0013]

It has been found that the object of the present invention can be achieved by any one of the following constitutions.

At least one surface of the cellulose ester film is coated with an ultraviolet curable composition containing a compound containing two or more epoxy groups in the molecule and a cationic polymerization initiator activated by active energy rays, and then the active energy is applied. A cellulose ester film for a polarizing plate, characterized in that a coating film cured by irradiating a ray is provided, and an easy adhesion treatment layer made of a hydrophilic binder is provided on the opposite surface of the cellulose ester film. Cellulose ester film described above The cationic polymerization initiator is composed of an aromatic onium salt. The cellulose ester film described above, wherein the curable composition contains at least one selected from an ultraviolet absorber and an antioxidant. The cellulose ester according to the above or, characterized in that Film A cellulose ester film as described above or characterized in that it comprises a composition containing amorphous silica in a cured coating film, wherein the cellulose ester film is produced as a protective film for a polarizing plate, or Cellulose ester film.

The present invention will be described in more detail below.

The compound containing at least two epoxy groups in the molecule, which is a constituent of the energy ray-curable composition used in the present invention, means an epoxy having an acrylic double bond in the molecule described in JP-A-1-105738. Unlike acrylate, it is an epoxy resin that polymerizes or cross-links upon irradiation with energy rays in the presence of a cationic polymerization initiator that is activated by active energy rays. As such, for example, a conventionally known aromatic epoxy resin,
Examples thereof include an alicyclic epoxy resin and an aliphatic epoxy resin, and an alicyclic epoxy resin is preferable from the viewpoint of curability. These can be used in combination to obtain the required performance. In a preferred embodiment of the present invention, the alicyclic epoxy resin is 20 to 80 parts by weight, preferably 40 to 60 parts by weight, and any one or more of the aromatic epoxy resin and the aliphatic epoxy resin is 80 to 20 parts by weight. It is preferable to use together 60 to 40 parts by weight.

The preferred aromatic epoxy resin is a polyglycidyl ether of a polyhydric phenol or its alkylene oxide adduct, for example, a glycidyl ether produced by reacting bisphenol or an alkylene oxide adduct with epichlorohydrin. , And epoxy novolac resin.

Preferred as the alicyclic epoxy resin are polyglycidyl ethers of polyhydric alcohols having at least two aliphatic rings or cyclohexene or cyclopentene ring-containing compounds, which are appropriately oxidized with hydrogen peroxide, peracid or the like. Examples thereof include cyclohexene oxide- or cyclopentene oxide-containing compounds obtained by epoxidation with an agent.

Typical examples of the alicyclic epoxy resin include hydrogenated bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 2- (3,4-epoxycyclohexyl).
-5,5-Spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene dioxide, bis (3,4-epoxy-6-methylcyclohexylmethyl) Adipate, 3,4-epoxy-6-methylcyclohexyl-3,4-epoxy-6-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane) dicyclopentadiene diepoxide, ethylene glycol di (3,4- Epoxycyclohexylmethyl) ether, ethylene bis (3,4-epoxycyclohexanecarboxylate), dicyclopentadiene diepoxide, etc. may be mentioned.

Preferred aliphatic epoxy resins are polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, polyglycidyl esters of aliphatic long-chain polybasic acids, homopolymers of glycidyl acrylate and glycidyl methacrylate, and copolyesters. Polymers and the like, and typical examples thereof are 1,4-butanediol glycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and sorbitol polyglycidyl ether. Polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, ethylene glycol, propylene glycol, aliphatic polyhydric alcohols such as glycerin Polyglycidyl ethers of polyether polyols obtained by adding the species or two or more alkylene oxides, diglycidyl esters of aliphatic long-chain dibasic acid, and epoxidized polybutadiene.

As the compound containing at least two epoxy groups in the molecule, which is a constituent of the energy ray-curable composition used in the present invention, monoepoxide or a cationically polymerizable organic substance other than the epoxy resin can be used in a desired performance. It can be blended and used accordingly.

For example, a monoglycidyl ether of an aliphatic higher alcohol as a monoepoxide that can be blended, phenol, cresol, butylphenol, or a monoglycidyl ether of a polyether alcohol obtained by adding an alkylene oxide to these, a higher Examples thereof include glycidyl ester of fatty acid, epoxidized soybean oil, butyl epoxystearate, octyl epoxystearate, and epoxidized linseed oil.

Examples of cationically polymerizable organic substances that can be blended are oxetane compounds such as trimethylene oxide, 3,3-dimethyloxetane, and 3,3-dichloromethyloxetane; tetrahydrofuran, and 2,3-dimethyltetrahydrofuran. Such oxolane compounds; cyclic acetal compounds such as trioxane, 1,3-dioxolane, 1,3,6-trioxanecyclooctane; cyclic lactone compounds such as β-propiolactone, ε-caprolactone; ethylene sulfide, 1, Thiilane compounds such as 2-propylene sulfide, thioepichlorohydrin;
Thiethane compounds such as 1,3-propylene sulfide-3,3-dimethylethane; ethylene glycol divinyl ether, polyalkylene glycol divinyl ether, alkyl vinyl ether, 3,4-dihydropyran-2-methyl (3,4-dihydropyran 2-carboxylates); spiro orthoester compounds obtained by reaction of epoxy compounds with lactones; ethylenically unsaturated compounds such as vinylcyclohexane, isobutylene, polybutadiene and derivatives of the above compounds.

As the polymerization initiator activated by the active energy ray, a compound capable of releasing a substance which initiates cationic polymerization upon irradiation with energy rays can be used, and particularly preferred is the initiation of polymerization upon irradiation. It is a group of double salts, which are onium salts that release a Lewis acid having a function.

A typical example of such a compound is [R ¹ _a R ² _b R ³ _c R ⁴ _d Z] ^{+ m} [MX _{n + m} ] ^-m [wherein the cation is onium and Z is S, Se, Te, P, A
s, Sb, Bi, O, halogen (for example, I, Br, Cl), or N = N, and R ¹ , R ² , R ³ , and R ⁴ are the same or different organic groups. a, b, c and d are each an integer of 0 to 3, and a + b + c + d is equal to the valence of Z. M is a metal or metalloid which is the central atom of the halide complex (me
talloid) and B, P, As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Z
n, Sc, V, Cr, Mn, Co, etc. X is halogen, m is the net charge of the halide complex ion, and n is the number of halogen atoms in the halide complex ion. ] Is represented.

Specific examples of the anion MX _{n + m} of the above general formula include tetrafluoroborate (BF ₄ ⁻ ), hexafluorophosphate (PF ₆ ⁻ ), hexafluoroantimonate (SbF ₆ ⁻ ), hexafluoroarsene. sulfonate (AsF ₆ ^-) hexachloroantimonate (SbCl ₆ ^-), and the like.

Furthermore, anions of the general formula MX _n (OH) ⁻ can also be used. Examples of other anions perchlorate ion (ClO ₄ ^-), trifluoromethyl sulfite ion (CF ₃ SO ₃ ^-) fluorosulfonic acid ion (FSO ₃ ^-) toluenesulfonate anion trinitro benzene sulfonic acid Anion etc. are mentioned.

Among these onium salts, it is particularly effective to use an aromatic onium salt as a cationic polymerization initiator. Among them, JP-A-50-151996 and 50-1586 are particularly preferable.
Aromatic halonium salts described in JP-A-80, JP-A-50-151
Group VIA aromatic onium salts described in JP-A Nos. 997, 52-30899, 56-55420, 55-125105 and the like, JP-A-50-15869
VA aromatic onium salts described in JP-A No. 8 and the like, JP-A-56-84
No. 28, No. 56-149402, No. 57-192429, etc. oxosulfoxonium salts, the aromatic diazonium salts described in JP-B-49-17040, etc., U.S. Patent No. 4,139,655, etc. The thiopyrylium salts described and the like are preferred. Also,
An aluminum complex / photolytic silicon compound-based initiator and the like are also included.

In the active energy ray-curable composition used in the present invention, the polymerization initiator is generally preferably 0.1 part by weight based on 100 parts by weight of the energy-curable prepolymer.
-15 parts by weight, more preferably 1 to 10 parts by weight.

The active energy ray-curable composition that can be used in the present invention may contain, in addition to the epoxy compound described above, a pigment,
Colorants such as dyes, defoaming agents, thickeners, leveling agents, flame retardants, UV absorbers, various fat additives such as antioxidants, fillers, modifying resins, etc. should be used in appropriate amounts. You can

In the present invention, when an ultraviolet curable composition is used as the active energy ray curable composition, the light source of irradiation light in the ultraviolet region (hereinafter also simply referred to as ultraviolet ray) to be used is sunlight, a low pressure mercury lamp, There are high-pressure mercury lamps, ultra-high-pressure mercury lamps, carbon arc lamps, metal halide lamps, xenon lamps, etc.

The atmosphere for irradiating the ultraviolet rays may be air or an inert gas such as nitrogen gas or carbon dioxide gas.

The irradiation time of ultraviolet rays to the ultraviolet-curable composition which can be used in the present invention varies depending on the kind of the irradiation light source in the above-mentioned ultraviolet region, but is preferably 0.5 seconds to 5 minutes, more preferably 3 seconds. ~ 2 minutes.

Usually, when the irradiation time is short, a large light source having a high irradiation intensity is required, and when the irradiation time is long, a light source having a low irradiation intensity can be used. It is a disadvantage. However, according to the present invention, it is possible to achieve the purpose by irradiation for 3 seconds to 2 minutes with an ultraviolet ray generating lamp of 200 W or less, which is advantageous.

Such a resin composition can be applied as a liquid resin material on a support, for example, the outermost layer on a belt-shaped support. To apply the liquid resin material to the layer surface, a means for applying the material solution by a usual method such as a double roll coater, a gravure offset coater, a slit coater, an air knife coater, a wire per coater, a slide hopper, and spray coating is used. be able to. The coating thickness at this time is arbitrary, but is 0.
1μ to 30μ is suitable. It is preferably 0.5 μ to 15 μ.

The ultraviolet absorbers used in the present invention include salicylic acid derivatives (UV-1), benzophenone derivatives (UV-2) and benzotriazole derivatives (UV-).
3), an acrylonitrile derivative (UV-4), a benzoic acid derivative (UV-5), an organic metal complex salt (UV-6) and the like. Examples of the salicylic acid derivative (UV-1) include phenyl salicylate, 4-tert-butylphenylsalicylic acid and p-octylphenylsalicylic acid.
Examples of the benzophenone derivative (UV-2) include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4-methoxybenzophenone and 2-hydrooxy-4. -Methoxy-
2'-carboxybenzophenone, 2-hydroxy-4-
Methoxy-5-sulfobenzophenone trihydrate, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-oxybenzylbenzophenone, 2-hydroxy-4-stearyloxybenzophenone, 2,2′-dihydro Oxy-4,4'-dimethoxybenzophenone and the like can be mentioned. Examples of the benzotriazole derivative (UV-3) include 2- (2'-hydroxy-5'-methylphenyl) -benzotriazole and 2- (2'-hydroxy-3 ', 5'-di-tert.
-Butylphenyl) -5-chlorobenzotriazole, 2-
(2'-Hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-
Butylphenyl) benzotriazole, 2- (3,5-di-ter
t-acyl-hydroxyphenyl) benzotriazole, 2
-(2'-Hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2 (2'-hydroxy-3 ',
5'-diisoamylphenyl) benzotriazole, 2-
(2'-Hydroxy-4'-octoxyphenyl) benzotriazole and the like, and as the acrylonitrile derivative (UV-4), 2-ethylhexyl-2-cyano-3,
3'-diphenyl acrylate, ethyl-2-cyano-3,3'-
Diphenyl acrylate, methyl-α-cyano-β-methyl
-β- (p-methoxyphenyl) acrylate and the like can be mentioned. As the benzoic acid derivative (UV-5), resorcinol-monobenzoate, 2 ′, 4′-di-tert-butylphenyl-3,5-di- Examples of the organic metal complex salt (UV-6) include tert-butyl-4-hydroxybenzoate and the like.
Nickel bis-octylphenyl sulfamide, [2,2 '
-Thiobis (4-tert-octylphenolate)]-n-butylamine nickel, a nickel salt of ethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphoric acid, and the like.

These ultraviolet absorbers may be used in combination of two or more kinds. The amount of these ultraviolet absorbers is preferably 0.1 to 15% by weight, more preferably 0.5 to 8% by weight, based on the total amount of the ultraviolet curable composition of the present invention.

The antioxidant used in the present invention includes:
For example, a hindered phenol derivative (AO-1), a thiodipropionic acid derivative (AO-2), a phosphite derivative (AO-3) and the like can be mentioned. Specific examples of the hindered-phenol derivative (AO-1) include 4,4′-thiobis (6-tert-3-methylphenol) and 4,4′-butylidenebis (6-tert-butyl-3-methyl). Phenol), 4,
4'-butylidene-bis (3-methyl-6-tert-butylphenol) 2,2'-thiobis (6-tert-butyl-4-methylphenol), 2,6-di-tert-butylphenol, 4,4 ' -Methylenebis (6-tert-butylphenol), 4,4'-bis (2,6
-Di-tert-butylphenol), 4,4'-methylenebis (6
-tert-butyl-o-cresol), 4,4'-thiobis (6-ter
t-butyl-o-cresol), 1,1,3-tris (5-tert-butyl-4-hydroxy-2-methylphenyl) butane, 2,
4,6-Tris (3,5-di-tert-butyl-4-hydroxybenzyl) mesitylene, 1,3,5-Tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate , 1,3
-Bis (3,5-di-tert-butyl-4-hydroxyphenyl) -2,2'-bis (2-dodecylthionitoxycarbonyl) propane, 1,6-bis (3,5-bi- tert-butyl-4-hydroxyphenylacetoxy) hexane, 6- (4-
Hydroxy-3,5-di-tert-butylanilino) -2,4-bis (n-octylthio) -1,3,5-triazine, tetrabis [β- (3,5-di-tert-butyl-4- Hydroxyphenyl) propionyloxymethyl] methane, n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-tert-butylphenyl) propionate, di-octadecyl-4-hydroxy-3,5 -Di-tert-butylbenzylphosphonate,
Di-ethyl-4-hydroxy-3,5-di-tert-butylbenzylphosphonate and the like can be mentioned. Examples of the thiodipropionic acid derivative (AO-2) include dilauryl-3,3′-thio-di-
-Propionate, di-stearylthio-di-propionate and the like, and examples of the phosphite derivative (AO-3) include tri-phenylphosphite, trisnonylphenylphosphite, di-phenyldecylphosphite,
Di-cresyl phosphite and the like can be mentioned.

These antioxidants may be used in combination of two or more kinds. The amount of these antioxidants is preferably 0.1 to 15% by weight, more preferably 0.2 to 6% by weight, based on the total amount of the ultraviolet curable composition of the present invention.

In the ultraviolet curable composition of the present invention, as long as it contains at least one selected from the above ultraviolet absorbers and antioxidants, only the ultraviolet absorbers or antioxidants alone, or a combination of both are used. May be. These may be dissolved directly, or may be added after being dissolved in a solvent such as acetone, methanol, ethyl acetate or toluene in advance.

In the constitution of the protective film for a polarizing plate of the present invention, an antistatic layer is provided on one side of the cellulose triacetate film, and a hydrophilic binder for adhering to the polarizing film is provided on the opposite side thereof.

Examples of the hydrophilic binder according to the present invention include -COOM group-containing vinyl acetate-maleic acid copolymer compounds or hydrophilic cellulose derivatives (for example, methyl cellulose, carboxymethyl cellulose, hydroxyalkyl cellulose, etc.), polyvinyl alcohol derivatives (for example, Vinyl acetate-vinyl alcohol copolymer, polyvinyl acetal, polyvinyl formal, polyvinyl benzal, etc.) natural polymer compounds (eg gelatin, casein gum arabic etc.), hydrophilic group-containing polyester derivatives (eg sulfone group-containing polyester copolymer) Can be mentioned.

The above object of the present invention is constituted by the following constitutions.

Dyeing In a polarizing film comprising a uniaxially stretched polarizing film made of polyvinyl alcohol and a protective film adhered adjacent thereto, at least the surface of the protective film to be adhered to the polarizing film has the following general formula [I]: Alternatively, a protective film for a polarizing plate, which is prepared by dissolving a -COOM group-containing copolymer compound represented by the general formula [II] in a solvent having an affinity for the protective film and forming the layer.

The specific --COOM group-containing copolymer compound used in the present invention is represented by the following general formula.

[0046]

[Chemical 1]

In the formula, A is a vinyl monomer, B is a hydrogen atom,
--CO--OM or-(CO)-R, when z = 0, B is a hydrogen atom, when R is an alkyl group, B is a hydrogen atom, M is hydrogen or a cation, and R is --O--R '. Alternatively, —N (R ″) (R ′) wherein R ′ is an alkyl group, an aralkyl group, an aryl group, a heterocyclic ring residue or a non-metal atom necessary for forming a heterocyclic ring in cooperation with R ″, R ″ is a hydrogen atom,
A non-metal atom necessary for forming a heterocyclic ring in cooperation with a lower alkyl group or R ', R ₁ and R ₂ are hydrogen atoms or a lower alkyl group, and X is-(CO) -O- or -O- ( CO)
-, R ₃ is a halogenoalkyl or halogenoalkyloxyalkyl group, m, p, q, r, x, y, and z are values each showing the mol% of each monomer, and m is 0 to 60,
p is 0 to 100, q is 0 to 100, r is 0 to 100, x is 0 to 60, y
Is 0 to 100, z is 0 to 100, and m + p + q + r = 100,
x + y + z = 100.

In the above general formula, examples of the vinyl monomer include styrene, nitro group, fluorine, chlorine, bromine, chloromethyl group, lower alkyl group-substituted styrene, vinyl methyl ether, vinyl ethyl ether, vinyl chloroethyl ether. , Vinyl acetate, vinyl chloroacetate,
Unsaturated acids such as vinyl propionate, acrylic acid, methacrylic acid or itaconic acid, alkyl acrylates or alkyl methacrylates having 1 to 5 carbon atoms, unsubstituted or substituted with chlorine, phenyl group, etc., phenyl acrylate or phenyl meta There are acrylate, acrylonitrile, vinyl chloride, vinylidene chloride, ethylene, acrylamide, acrylamide substituted with an alkyl group having 1 to 5 carbon atoms or chlorine, a phenyl group, vinyl alcohol, chrysidyl acrylate, acrolein, etc., preferably styrene, substituted Examples thereof include styrene having a group, vinyl acetate, vinyl methyl ether, alkyl acrylate, and acrylonitrile.

The alkyl group represented by R'in the above formula is preferably one having 1 to 24 carbon atoms, and a linear alkyl group,
It may be any of alkyl groups such as a branched alkyl group and a cycloalkyl group, and the alkyl group may have a substituent, and the substituent may be a hydroxy group, a hydroxycarbonyl group, a cation oxycarbonyl group or the like. In particular, a halogen-substituted halogenoalkyl group or a halogenoalkyloxyalkyl group such as fluorine gives desirable results, and is a halogenoalkyl group having 2 to 18 carbon atoms, a halogenoalkyloxyalkyl group or a halogenocycloalkyl group. Thus, the halogen number is preferably 1-37. The halogenoalkyl group and the halogenoalkyloxyalkyl group, and the halogenoalkyl group and the halogenoalkyloxyalkyl group of R _{3 in} the above formula are
It is preferably represented by the following general formula [A].

[0050]

[Chemical 2]

(In the formula, R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ are hydrogen or fluorine, n ₂ is 0 or 1, and when n ₂ is 0, n ₁ is 0 and n ₂ is When 1, n ₁ is 2 or 3, n ₃ is an integer of 1 to 17, where n ₁ + n ₃ is 1 to 17. However, when R ₄ is 2 or more in the structural formula, 1 They may be different groups such that one is hydrogen and the other is fluorine,
Similarly, when a plurality of R ₅ , R ₆ and R ₇ are present in the structural formula, they may be different groups. ) Further, when R'in the general formula [I] and the general formula [II] is a halogenoalkyl group or a halogenoalkyloxyalkyl group as described above, preferably, the general formula [I] and the general formula [II] ] In R] is -O-R '. An aryl group such as a phenyl group of R'or an aralkyl group such as a benzyl group may have a substituent, and as the substituent, a halogen lower alkyl group such as fluorine, chlorine, bromine or a hydroxy group can be used. -Hydroxycarbonyl group, cation oxycarbonyl group, nitrile group, nitro group and the like. In the formula, the heterocyclic ring of R'or the heterocyclic ring formed by R'and R "is a saturated or unsaturated heterocyclic ring containing oxygen, sulfur, or nitrogen, for example, aziridine pyrrole. A heterocyclic ring selected from heterocyclic rings such as pyrrolidine, pyrazole, imidazole, imidazoline, triazole, piperidine, piperazine, oxazine, morpholine, thiazine, etc. In the formula, the cation of M is, for example, ammonium ion or sodium ion. , Potassium ion, lithium ion and the like.

The --COOM group-containing copolymer compound represented by the above general formula may be used alone or in combination of two or more kinds, and preferably has an average molecular weight of about 500 to 500,000 (weight average).
Something is used.

Typical examples of the above-mentioned copolymer compound used in the present invention include the following. However, the present invention is not limited to these.

[0054]

[Chemical 3]

The --COOM group-containing copolymer compound represented by the above general formula used in the present invention is synthesized by a known method. That is, it is well known that the maleic anhydride copolymer is a very general polymer, and these derivatives also can be obtained by reacting a maleic anhydride copolymer with an alcohol or amine compatible with them. It can be easily obtained, or can be obtained by reacting a maleic anhydride monomer with a compatible alcohol or amine and purifying the product and copolymerizing it with another vinyl monomer. In addition, acrylates such as halogenoalkyl and halogenoalkyloxyalkyl are available in Journal of Polymer Science.
Science. 15 515-574 (1955) or British Patent 1,121,
It is easily synthesized by the method for synthesizing monomers and polymers described in the specification of No. 357. According to the present invention, the amount of the copolymer compound used is 10 to
It is preferably 1000 mg / m ² , more preferably 20 to 300 mg / m ^2.
This is especially desirable.

The protective film used in the present invention is mainly composed of cellulose triacetate, but cellulose diacetate, cellulose acetate butyrate, cellulose ester such as cellulose propionate, polycarbonate, polyethylene terephthalate, polyacrylate and the like are also applicable. . Particularly in the case of cellulose triacetate, a plasticizer-containing material such as triphenyl phosphate, biphenyl diphenyl phosphate, dimethyl ethyl phosphate is usually used.

These supports differ depending on the polymer species, but the thickness is from about 1 mm sheet to about 20 μm thin film, depending on the application, but 30 is commonly used.
The thickness range is up to 150 μm. If desired, the protective film may contain an ultraviolet absorber, a plasticizer, a slip agent, a matting agent and the like.

The polymer solution according to the present invention is a gravure coater, a dip coater, a reverse roll coater,
It can be applied by a known method such as an extrusion coater. The coating amount of the polymer according to the present invention is in the range of 10 to 1000 mg / m ² ,
20 to 30 in terms of particularly stable adhesive strength and finish after application
0 mg / m ² is preferred. The method of applying the coating solution and then drying it is not particularly limited, but the residual solvent amount after drying is 5% by weight.
The following is preferable. If the amount of residual solvent is large, air bubbles may be generated at the adhesive interface in the drying process after being laminated with the polarizing film, which is not preferable.

If desired, an ultraviolet absorber, a slip agent, a matting agent, an antistatic agent, a crosslinking agent, an activator and the like may be added to the polymer solution according to the present invention.

A cross-linking agent is particularly preferable for promoting the adhesion of the polarizing film with the polyvinyl alcohol film. Examples of such a cross-linking agent include polyvalent epoxy compounds, aziridine compounds, isocyanate compounds, bright vanes, boron compounds and the like.

Examples of the adhesive used for bonding the treated surface of the protective film and the polarizing film according to the present invention include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latex such as butyl acrylate and the like. Can be given.

A matting agent such as SiO ₂ or TiO ₂ may be added to the cured layer of the present invention for the purpose of improving antiglare treatment.

[0063]

EXAMPLES The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 A coating composition according to the present invention shown below was applied to one side of a cellulose triacetate film having a thickness of 70 μm so as to give a coating thickness of 10 μm, and it was exposed under a high pressure mercury lamp of 60 w / cm ² at a distance of 10 cm for 4 seconds. , So that the composition is allowed to cure.

Coating Composition 1 3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 65 parts by weight Bisphenol A diglycidyl ether 20 parts by weight Trimethylolpropane triglycidyl ether 15 parts by weight Aromatic sulfonium salt UV Initiator 6 parts by weight 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole 1 part by weight The following composition containing a hydrophilic binder on the opposite side of the triacetate film provided with the above cured coating film. The product was applied at 25 ml / m ² and further dried at 90 ° C. for 10 minutes to provide an adhesive layer.

Liquid composition Exemplified compound (1) 10 parts by weight Water 20 parts by weight Methanol 400 ml Acetone 600 ml Example 2 Coating composition 2 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 35 parts by weight Bis ( 3,4-Epoxycyclohexylmethyl) adipate 20 parts by weight Hydrogenated bisphenol A diglycidyl ether 30 parts by weight Pentaerythritol polyglycidyl ether 15 parts by weight Silicone-based surfactant 3 parts by weight Aromatic sulfonium salt-based UV initiator 5 parts by weight 2 -Hydroxy-4-methoxybenzophenone 1.2 parts by weight 4,4'methylenebis (6-tert-butylphenol) 0.8 parts by weight The above coating composition was used to form a cured coating film in the same manner as in Example 1, and further cured coating film was formed. 25 ml of the following composition containing a hydrophilic binder on the side opposite to the membrane-provided triacetate film
The adhesive layer was formed by coating so as to be / m ² and further drying at 90 ° C. for 10 minutes.

Liquid composition Exemplified compound (3) 5 parts by weight Ethyl acetate 500 ml Acetone 500 ml Example 3 Silicon oxide (Cyloid 244 manufactured by Fuji Devison Chemical Co., Ltd.) 75 parts by weight 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxy Rate 50 parts by weight Toluene 50 parts by weight The above composition was dispersed for 5 hours with a sand grinder using glass beads as a medium.

The above dispersion composition thus obtained was mixed with the coating composition of Example 2 in a weight ratio of 2:98, and coated and cured in the same manner as in Example 1.

Comparative Example 1 A sample having a cured coating film was prepared from the following composition in the same manner as in Example 1.

Comparative composition 1 epoxy acrylate 60 parts by weight pentaerythritol triacrylate 40 parts by weight benzoin ethyl ether 5 parts by weight Further, the above film was immersed in a potassium hydroxide aqueous solution having a temperature of 70 ° C. and a concentration of 15 wt% for 90 seconds and washed with water. To form a saponification layer.

Comparative Example 2 Epoxy acrylate 60 parts by weight Pentaerythritol triacrylate 40 parts by weight Aromatic sulfonium salt type UV initiator 5 parts by weight The initiator of the present invention was used in place of the initiator of Comparative Example 1 and Example 1 was used. It was cured by the same method as above, but it was not cured and the surface was sticky.

A polarizing plate was prepared by using the above-mentioned cellulose acetate film as a protective film and adhering both sides of a polarizing film prepared by the following method with an acrylic adhesive.

How to make a polarizing plate film A polyvinyl alcohol film having a thickness of 120 μm was added to 1 part by weight of iodine, 2 parts by weight of potassium iodide, and 4 parts of boric acid.
It was immersed in an aqueous solution containing 1 part by weight and stretched 4 times at 50 ° C. to obtain a polarizing film.

Each of the above polarizing plates cut into a size of 20 cm square was allowed to stand in a high temperature and high humidity atmosphere of 80 ° C. × 90% RH for 1000 hours, and the degree of change in its spectral absorption characteristics and between the polarizing film and the cellulose triacetate protective film. The presence or absence of peeling was evaluated.

1. Abrasion resistance The cured coating film was rubbed 50 times with a nylon scrubbing brush (Sumitomo 3M, Scotch Bright) at a pressure of 1 kg / 25 cm ² to evaluate the state of scratches on the surface.

◯: No scratches were generated and scratch resistance was good. Δ: Scratches were slightly observed, but practically usable. ×: Many scratches were observed and practically unusable.

2. Adhesion of Cellulose Triacetate Film Support (1) Cellotape (manufactured by Nichiban Co., Ltd.) was strongly adhered to the surface of the cured coating film, and the cellotape was rapidly peeled from the surface, and then the peeled state was observed.

(2) The surface of the cured coating film was scratched with a cutter at an angle of 90 °, and the adhesion was observed at that location in the same manner as in (1).

(3) The cellulose triacetate film provided with the cured coating film was left in an atmosphere of 80 ° C. and 95% RH for 500 hours, and then the surface of the cured coating film was scratched with a cutter at an angle of 90 °. The adhesiveness of was observed in the same manner as in (1).

○: No peeling at all Δ: 1/3 of the area of the bonded cellophane tape was peeled off (peeled between the cured coating film and the cellulose triacetate film) ×: Of the area of the bonded cellophane tape More than half peeled off (peeled between cured coating and cellulose triacetate film). Chemical resistance Immerse each solvent in gauze, and use the gauze to clean the surface of the cured coating.
After wiping 10 times and drying at room temperature, the state of the surface of the coating film was observed.

O: No abnormality X: The surface of the cured coating film was whitened and practically unusable.

4. Flexible Cellulose triacetate film coated with a cured coating was wrapped around a mandrel with a diameter of 10 mm so that the coating was on the outside, and the occurrence of 180 ° bending cracks was examined.

◯: No cracks occurred Δ: Cracks occurred ×: Crisp sound was generated and cracks occurred.

5. Moisture and Heat Resistance Test of Polarizing Plates Using the protective films obtained in Examples and Comparative Examples, polarizing plates were prepared by the following method, and each polarizing plate was 5 cm × 7 cm.
Cut to size. The cut pieces obtained are each 6 cm x 8 cm
Each of the cuts was attached to the glass plate by temporarily adhering it to the central part of the glass plate with an acrylic adhesive and then pressing them to completely remove the bubbles between each piece and the glass plate.

The test pieces thus prepared were placed vertically in a constant temperature and humidity oven set at 80 ° C. and 95% RH so as not to overlap each other, and fixed on a supporting frame for 1000 hours. The discoloration of the plate, (B) the adhesion between the polarizing film and the protective film, and (C) the degree of polarization were measured.

(A) Evaluation of Discoloration of Polarizing Plate: Color difference meter (measured by Suga Test Instruments Co., Ltd. and evaluated by the value of color difference change ΔE (NBS unit)).

○ ・ ・ ・ 2 or less △ ・ ・ ・ 2-5 × ・ ・ ・ 5 or more (B) Evaluation of adhesiveness between the polarizing film and the protective film: The polarizing film and the protective film were protected by visual observation after high temperature and high humidity treatment. The peeled state between the films was evaluated.

○: The floating portion of the film is 1 mm around the periphery
Below △: the raised portion of the film is in the range of 1 to 5 on the periphery × ... 5 mm or more of the raised portion of the film is in the periphery (C) Evaluation of transmittance and polarization degree: values in the region of 400 to 700, It was calculated based on the following formula from the average value of transmission at the time of parallel and at the time of going straight. However, the transmittance was corrected to 43%.

P = [(HO-H90) / (HO + H90)] × 100 (where P is the degree of polarization, HO is the average parallel transmittance, and H90 is the average orthogonal transmittance). Within ± 2% from the measured value (43%) of Δ △ ・ ・ ・ Difference from measured value of the original piece (43%) ± 2% to ± 5% × ・ ・ ・ Measured value of the original piece (43%) The difference is ± 5% or more. The results are shown in Tables 1 and 2.

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[Table 1]

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[Table 2]

From the results shown in Tables 1 and 2, the protective film itself has particularly improved adhesion and flexibility of the cured coating film, and, of course, has excellent abrasion resistance and chemical resistance. It can be seen that even when assembled into a plate, the adhesiveness (hardness to peel off) with the polarizing film (hardness of peeling), the discoloration, the durability such as the change of the degree of polarization are particularly improved.

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EFFECTS OF THE INVENTION 1) First, a cellulose ester film for a protective film of a polarizing plate having excellent abrasion resistance and chemical resistance. 2) Secondly, a polarizing plate having excellent adhesion to a film support. Cellulose ester film for protective film of 3) Thirdly, a cellulose ester film for protective film of a polarizing plate having excellent flexibility can be provided.

Claims (6)

[Claims] 1. A UV-curable composition containing a compound containing two or more epoxy groups in the molecule and a cationic polymerization initiator activated by active energy rays, on at least one surface of a cellulose ester film. A cellulose ester film having a coating film cured by irradiation with active energy rays. 2. The cellulose ester film according to claim 1, wherein an easy-adhesion treatment layer made of a hydrophilic binder is provided on the opposite surface of the cellulose ester film. 3. The cellulose ester film according to claim 1, wherein the cationic polymerization initiator comprises an aromatic onium salt. 4. The cellulose ester film according to claim 1, wherein the curable composition contains at least one selected from an ultraviolet absorber and an antioxidant. 5. The cellulose ester film according to claim 1, wherein the cured coating film is composed of a composition containing amorphous silica. 6. The cellulose ester film according to claim 1, 2 or 3, wherein the cellulose ester film is produced as a protective film for a polarizing plate.