KR20160031418A - Thermoplastic resin film - Google Patents

Abstract

Provided is a thermoplastic resin film which has an excellent heat-resisting property, and is hard to be shrunk at high temperatures and fractured by elongation, thereby being suitable for a protective film for a polarizer. Provided is the thermoplastic resin film consisting of: a resin (A) containing a methacrylic acid ester monomer unit and an aromatic vinyl monomer unit; and a resin (B) containing the methacrylic acid ester monomer unit but no aromatic vinyl monomer unit. The resin (A) contains 50 wt% or more of the aromatic vinyl monomer unit per 100 wt% of all monomer units composing the resin (A), and the resin (B) contains 50 wt% or more of the methacrylic acid ester monomer unit per 100 wt% of all monomer units composing the resin (B). A ratio of the weight of the resin (B) (W_B) to a methacrylic acid ester monomer unit content in the resin (A) (W_A) (W_B/W_A) is higher than 1.

Description

[0001] THERMOPLASTIC RESIN FILM [0002]

The present invention relates to a thermoplastic resin film and relates to a stretched film and a polarizer protective film formed by stretching the same.

The liquid crystal display usually has a polarizing plate and a polarizer protective film for protecting a polarizer is disposed on at least one surface of a polarizer made of a polyvinyl alcohol based resin in which a dichroic dye is normally adsorbed and aligned .

The liquid crystal display device is often used in a high temperature environment such as a car interior of an automobile and the polarizer has a property of being easily shrunk in a high temperature environment. Therefore, the liquid crystal display device is excellent in heat resistance, A polarizer protective film which is difficult to shrink is required.

In general, as the polarizer protective film, a stretched film made by stretching a thermoplastic resin film or a thermoplastic resin film is used. Patent Document 1 discloses that a stretched film obtained by stretching a thermoplastic resin film comprising an acrylic copolymer having a (meth) acrylic acid monomer unit, a vinyl aromatic monomer unit and a lactone ring monomer unit is used as a polarizer protective film, The thermoplastic resin film described in 1 was susceptible to breakage by stretching and there was room for improvement in handling properties at the time of stretching.

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-63541

The present inventors have intensively studied to provide a thermoplastic resin film which is excellent in heat resistance, is difficult to shrink in a high temperature environment and is hardly broken by stretching, and has reached the present invention.

The present invention includes the following.

[1] A thermoplastic resin composition comprising a resin (A) comprising a methacrylic acid ester monomer unit and an aromatic vinyl monomer unit, and a thermoplastic resin containing a methacrylic acid ester monomer unit and a resin (B) containing no aromatic vinyl monomer unit As the thermoplastic resin film,

Wherein the resin (A) is a resin having an aromatic vinyl monomer unit content of 50 wt% or more based on 100 wt% of all the monomer units constituting the resin (A)

Wherein the resin (B) is a resin having a methacrylic acid ester monomer unit content of 50% by weight or more based on 100% by weight of all the monomer units constituting the resin (B)

Wherein the ratio (W _B / W _A ) of the weight (W _B ) of the resin (B) to the content (W _A ) of the methacrylic acid ester monomer units in the resin ( _A )

[2] The thermoplastic resin film according to [1], wherein the resin composition further contains rubber elastomer particles.

[3] The resin composition according to [1] or [2], wherein the resin (A) further comprises a cyclic acid anhydride monomer unit and the melt mass flow rate of the resin composition is 1.2 g / Thermoplastic resin film.

[4] A stretched film obtained by stretching the thermoplastic resin film according to any one of [1] to [3].

[5] A polarizer protective film comprising a thermoplastic resin film according to [1] to [3] or a stretched film according to [4].

[6] A polarizer comprising a polarizer protective film according to [5] arranged on at least one side of a polarizer.

According to the present invention, it is possible to provide a thermoplastic resin film which is excellent in heat resistance, is difficult to shrink in a high temperature environment and is hard to be broken by stretching, and a stretched film obtained by stretching it. It is also possible to provide a polarizer protective film made of such a thermoplastic resin film or a stretched film and to provide a polarizer in which the polarizer protective film is disposed on one surface of the polarizer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view showing a method for producing a thermoplastic resin film according to an embodiment of the present invention. FIG.

[Resin composition]

The thermoplastic resin film of the present invention comprises a resin composition, wherein the resin composition comprises a resin (A) comprising a methacrylic acid ester monomer unit and an aromatic vinyl monomer unit, and a methacrylic acid ester monomer unit, (B) that does not contain a monomer unit.

[Resin (A)]

The resin (A) constituting the resin composition is a resin containing a methacrylic acid ester monomer unit and an aromatic vinyl monomer unit.

The methacrylic acid ester monomer unit is a monomer unit derived from a methacrylic acid ester monomer. Examples of the methacrylic acid ester monomer include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert- , 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and other alkyl or cycloalkyl ester monomers having 1 to 8 carbon atoms in methacrylic acid. Two or more kinds of methacrylic acid ester monomers may be used in combination. Among them, an alkyl ester monomer having 1 to 7 carbon atoms in methacrylic acid is preferable, and methyl methacrylate is more preferable in view of the heat resistance and transparency of the resin (A).

The content of the methacrylic acid ester monomer units in the resin (A) is preferably 5% by weight to 40% by weight based on 100% by weight of all the monomer units constituting the resin (A) By weight, more preferably from 5% by weight to 35% by weight, even more preferably from 10% by weight to 30% by weight, and particularly preferably from 15% by weight to 25% by weight.

The aromatic vinyl monomer unit is a monomer unit derived from an aromatic vinyl monomer. In the present specification, the aromatic vinyl monomer means a monomer having a structure in which an unsubstituted vinyl group or substituted vinyl group is bonded to an aromatic ring. Specific examples of the aromatic vinyl monomer unit include the following formula (1)

(Wherein R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group, a nitro group or an alkyl group having 1 to 12 carbon atoms, and n represents an integer of 1 to 3)

And the like.

Examples of the halogen atom in the formula (1) include a fluorine atom, a chlorine atom and a bromine atom. Examples of the alkyl group having 1 to 12 carbon atoms include a linear or branched alkyl group such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, , And an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group is more preferable.

R ¹ is preferably a hydrogen atom or a methyl group. R ² is preferably a hydrogen atom, and n is preferably 1. R ¹ and R ² may be the same or different.

Examples of the aromatic vinyl monomer include aromatic vinyl monomers such as styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, ? -Methylstyrene,? -Methylstyrene,? -Methylstyrene,? -Methylstyrene,? -Methylstyrene,? -Methylstyrene, Styrene, 4-bromo -? - methylstyrene, 4-tert-butylstyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene, 2,4-difluorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, 2-bromostyrene, 3-bromostyrene, 4-bromostyrene, 2,4-dibromo Styrene,? -Bromostyrene,? -Bromostyrene, 2-hydroxystyrene and 4-hydroxystyrene, and styrene and? -Methylstyrene are preferable. Two or more kinds of aromatic vinyl monomers may be used in combination.

The content of the aromatic vinyl monomer units in the resin (A) is 50% by weight or more based on 100% by weight of all the monomer units constituting the resin (A). Since the thermoplastic resin film of the present invention contains such a resin (A), it becomes a thermoplastic resin film excellent in dimensional stability in a high temperature environment. The content of the aromatic vinyl monomer unit in the resin (A) is preferably 50% by weight to 80% by weight from the viewpoints of transparency, heat resistance and dimensional stability in a high temperature environment of the thermoplastic resin film of the present invention, 55% by weight to 75% by weight, and more preferably 60% by weight to 70% by weight.

The resin (A) preferably includes a cyclic acid anhydride monomer unit. The cyclic acid anhydride monomer units are derived from cyclic acid anhydride monomers. Specific examples of the cyclic acid anhydride monomer unit include a cyclic acid anhydride monomer unit represented by the following formula (2)

(Wherein R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms or a phenyl group)

And cyclic acid anhydride monomer units represented by the following general formula (1).

Examples of the halogen atom and the alkyl group having 1 to 12 carbon atoms in the formula (2) are the same as those described in the formula (1).

R ³ and R ⁴ are preferably hydrogen atoms. R ³ and R ⁴ may be the same or different.

Examples of the cyclic acid anhydride monomer include maleic anhydride, citraconic anhydride, dimethyl maleic anhydride, dichloro maleic acid, bromomeric maleic acid, dibromomeric maleic acid, phenyl maleic anhydride and diphenyl maleic anhydride. And maleic anhydride is preferable. Two or more cyclic acid anhydride monomers may be used in combination.

The content of the cyclic acid anhydride monomer units in the resin (A) is preferably 5% by weight or more, more preferably 5% by weight or less, more preferably 5% by weight or less, 30% by weight, more preferably 10% by weight to 25% by weight, and particularly preferably 10% by weight to 20% by weight.

The resin (A) may contain monomer units other than the above-mentioned monomer units, that is, methacrylate ester monomer units, aromatic vinyl monomer units and cyclic acid anhydride monomer units, so long as the effects of the present invention are not impaired. The monomer units other than the monomer units described above are monomer units derived from monomers capable of copolymerizing with at least one monomer among the monomers that derive the monomer units described above. Preferably, the above three monomer units Is a monomeric unit derived from a monomer capable of copolymerizing with all of the monomers to be derived. The content of the monomer units other than the monomer units described above is preferably 50% by weight or less, more preferably 30% by weight or less, further preferably 30% by weight or less, relative to 100% by weight of all the monomer units constituting the resin (A) By weight is not more than 10% by weight.

The weight average molecular weight of the resin (A) is preferably from 90,000 to 300,000, more preferably from 100,000 to 300,000, from the viewpoint of handling of the film during molding of the thermoplastic resin film of the present invention or stretching of the thermoplastic resin film of the present invention To 250,000, and more preferably from 110,000 to 200,000.

The resin (A) can be produced by polymerizing each monomer by a known method such as a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method and a template polymerization method. By changing the amount of monomer used , The content of each monomer unit in the resin (A) can be adjusted.

[Resin (B)]

The resin (B) constituting the resin composition is a resin containing a methacrylic acid ester monomer unit and not containing an aromatic vinyl monomer unit.

Examples of the methacrylic acid ester monomer for deriving the methacrylic acid ester monomer unit include the same ones as described above in the resin (A), and methyl methacrylate is preferable. Two or more methacrylic acid ester monomer units may be contained.

It is preferable that the methacrylic acid ester monomer unit in the resin (A) and the methacrylic acid ester monomer unit in the resin (B) are the same.

The content of the methacrylic acid ester monomer units in the resin (B) is 50% by weight or more, preferably 70% by weight or more, relative to 100% by weight of all the monomer units constituting the resin (B) Is 90% by weight or more, and more preferably 95% by weight.

The resin (B) is a resin that does not contain an aromatic vinyl monomer unit, that is, a resin having a content ratio of aromatic vinyl monomer units of 0 (zero)% by weight, but other monomers other than a methacrylic acid ester monomer unit and an aromatic vinyl monomer unit Unit may be included. Examples of other monomers include acrylic acid ester monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate;

Non-substituted or substituted styrene monomers such as styrene, vinyl toluene,? -Methyl styrene, chlorostyrene, and bromostyrene;

Unsaturated carboxylic acid monomers such as methacrylic acid and acrylic acid; Unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile;

Cyclic acid anhydride monomers such as maleic anhydride;

Cyclic imide monomers such as phenylmaleimide and cyclohexylmaleimide, and acrylic acid ester monomers are preferred.

The weight average molecular weight of the resin (B) is preferably from 90,000 to 300,000, more preferably from 100,000 to 300,000, from the viewpoint of the handling of the film during molding of the thermoplastic resin film of the present invention or the stretching of the thermoplastic resin film of the present invention To 250,000, and more preferably from 110,000 to 200,000.

The resin (B) can be produced by polymerizing the methacrylic acid ester monomer and, if necessary, other monomers by a known method such as a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method and a template polymerization method .

[Thermoplastic film of the present invention]

The thermoplastic resin film of the present invention is composed of a resin composition containing a resin (A) and a resin (B).

When the thermoplastic resin film of the present invention has a ratio (W _B / W _A ) of the weight (W _B ) of the resin (B) to the content (W _A ) of the methacrylic acid ester monomer units in the resin ( _A ) In the case of the resin composition, since the W _B / W _A is larger than 1, the thermoplastic resin film is excellent in handleability and hardly broken at the time of stretching. The ratio (W _B / W _A ) is more preferably 1.5 or more, and usually 30 or less.

The content of the resin (A) and the resin (B) in the resin composition constituting the thermoplastic resin film of the present invention, the content of methacrylic acid ester monomer unit in the resin (A) (W _A) the ratio (W according to the there is suitably selected so as to satisfy the _B / W _a), for example the content of the resin (a) and the resin (B) a resin (a) for 100 parts by weight of the total amount of is usually 10 parts by weight to 80 parts by weight, preferably 20 to 75 parts by weight, and the content of the resin (B) is usually 20 to 90 parts by weight, preferably 25 to 80 parts by weight.

The resin composition may contain rubber elastomer particles in addition to the resin (A) and the resin (B). As the rubber elastomer particles, commercially available rubber elastomer particles can be used. Examples of the rubber elastomer particles include " PARAROID ^TM " EXL series sold by Dow Chemical Company, " Kane Ace (registered trademark) " series sold by KANEKA KABUSHIKI KAISHA, "Metabren" C series, E series, W series, and S series sold by Mitsubishi Rayon Co., Ltd. are examples.

The particle size of the rubber elastomer particles is, for example, 50 nm to 0.8 m, preferably 0.1 m to 0.5 m. When the particle size of the rubber elastomer particles is less than 50 nm, the fluidity of the rubber composition tends to deteriorate when the resin composition is processed into a film. If the particle diameter exceeds 0.8 占 퐉, the internal haze of the thermoplastic resin composition tends to be high. The particle diameter of the rubber elastomer particles can be measured as a number average molecular weight by observation of an electron microscope.

The content of the rubber elastomer particles is usually 2 parts by weight to 50 parts by weight, preferably 5 parts by weight to 35 parts by weight, based on 100 parts by weight of the total amount of the resin (A) and the resin (B).

The thermoplastic resin film of the present invention is produced by mixing the resin (A) and the resin (B) in such a manner that W _B / W _A is larger than 1, depending on the content (W _A ) of methacrylic acid ester monomer units in the resin To obtain a resin composition, and then, for example, as shown in Fig. 1, the resin composition can be formed into a film by a melt extrusion molding method. It is also possible to produce the resin composition by a film forming method such as a solution softening film method or a hot press method. Among them, it is preferable to produce a thermoplastic resin film by a melt extrusion molding method.

A method for producing the thermoplastic resin film of the present invention by melt extrusion molding will be described below. The resin (A) and the resin (B) are combined so that W _B / W _A is larger than 1, and if necessary, other components to be described later are added to obtain a resin composition. The obtained resin composition is then extruded into a single- And the molten resin is extruded continuously from the T-die in the form of a film, and the extruded film-like molten resin is melt-kneaded by a cooling roll (a first cooling roll and a second cooling Roll), and if necessary, it is wound around a third cooling roll, followed by molding and cooling, whereby an elongated thermoplastic resin film can be produced in an unstretched state. The mixing method of the resin (A), the resin (B) and other components is not limited, and may be blended by known methods, and may be either a super mixer or a Benbury mixer or may be melt-kneaded by a single screw or twin screw extruder Or a combination thereof may be used. The first cooling roll, the second cooling roll and the third cooling roll may be constituted by a metal roll or a metal elastic roll, or a combination of a metal roll and a metal elastic roll.

When the thermoplastic resin film of the present invention is a thermoplastic resin film containing the resin (A) and the resin (B) and further containing the rubber elastomer particles, the resin (A), the resin (B) To obtain a thermoplastic resin composition, and then forming the film by melt extrusion molding as described above. Further, it may be produced by a method such as film formation by a solution flexible film method or a hot press method. It is preferably a melt extrusion molding method.

When the thermoplastic resin film of the present invention is a thermoplastic resin film containing a resin (A) and a resin (B) and further containing rubber elastomer particles, a method of producing the thermoplastic resin film of the present invention by melt extrusion molding Will be described below. The resin (A), the resin (B) and the rubber elastomer particles are combined so that W _B / W _A is larger than 1, and if necessary, other components to be described later are added to obtain a resin composition. Melt-kneaded by a twin-screw extruder, and the molten resin is extruded continuously from the T-die in a film form, and the extruded film-type molten resin is cooled on a pair of cooling rolls A second cooling roll) and, if necessary, further wound on a third cooling roll, followed by molding and cooling, whereby an elongated thermoplastic resin film can be produced in an unstretched state. The mixing method of the resin (A), the resin (B), the rubber elastomer particles and the other components is not limited and may be blended by known methods, and may be a super mixer or a Benbury mixer, Or may be blended in combination. The first cooling roll, the second cooling roll and the third cooling roll may be constituted by a metal roll or a metal elastic roll, or a combination of a metal roll and a metal elastic roll.

The thermoplastic resin film of the present invention may contain components other than the resin (A) and the resin (B). Examples of other components include a light diffusing agent, a matting agent, a dye, a light stabilizer, an ultraviolet absorber, an antioxidant, a releasing agent, a flame retardant, an antistatic agent and other resins (resins other than the resin (A) and the resin (B) .

The thermoplastic film of the present invention preferably contains an ultraviolet absorber, more preferably an ultraviolet absorber (hereinafter referred to as ultraviolet absorber X) having an absorption maximum at a wavelength of 200 to 320 nm, an absorption maximum at a wavelength of 320 to 400 nm (Hereinafter referred to as ultraviolet absorber Y).

Examples of the ultraviolet absorber X include a triazine-based ultraviolet absorber having an absorption maximum at a wavelength of 200 to 320 nm, a benzophenone ultraviolet absorber having an absorption maximum at a wavelength of 200 to 320 nm, a benzotriazole ultraviolet absorber having an absorption maximum at a wavelength of 200 to 320 nm Absorbing agent, a benzoate-based ultraviolet absorber having an absorption maximum at a wavelength of 200 to 320 nm, and a cyanoacrylate ultraviolet absorber having an absorption maximum at a wavelength of 200 to 320 nm.

As the ultraviolet absorber X, for example,

Methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-ethoxy Phenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4- -Butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) , 2,6-diphenyl-4- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4- Triazine, 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, Phenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4- Triazin-2-yl) -5- (2- (2-ethylhexahydroxyphenyl) -1,3,5- Nonyloxy) ethoxy) phenol,

2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2 -Hydroxy-4-octadecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2 4,4'-tetrahydroxybenzophenone 2- (2-hydroxy-3,5-di-tert-pentylphenyl) benzotriazole,

Di-tert-butylphenyl 3 ', 5'-di-tert-butyl-4'-hydroxybenzoate, 2,6- Butyl-4-hydroxybenzoate, n-hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, n-octadecyl 3,5- Eight,

2-ethylhexyl 2-cyano-3,3-diphenylacrylate and ethyl 2-cyano-3- (3,4-methylenedioxyphenyl) acrylate.

Examples of the ultraviolet absorber Y include a triazine-based ultraviolet absorber having an absorption maximum at a wavelength of 320 to 400 nm, a benzophenone ultraviolet absorber having an absorption maximum at a wavelength of 320 to 400 nm and a benzotriazole ultraviolet absorber having an absorption maximum at a wavelength of 320 to 400 nm Absorbent agent.

As the ultraviolet absorber Y, for example,

2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine,

2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-

2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert- butylphenyl) benzotriazole, 2- -Butyl-5-methylphenyl) benzotriazole,

2- (2-hydroxy-3,5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2- Methylphenyl) benzotriazole, 2,2'-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol- ), 2- (2-hydroxy-3,5-di-tert-butylphenyl) -5-chlorobenzotriazole, and 2- Chlorobenzotriazole, and the like.

Two or more ultraviolet absorbers X may be used in combination, or two or more ultraviolet absorbers Y may be used in combination. The ultraviolet absorber X having the similar structure and the ultraviolet absorber Y may be used in combination or the ultraviolet absorber X having no similar structure and the ultraviolet absorber Y may be used in combination. In view of being able to obtain a thermoplastic resin film having little contamination around the molding machine due to the amount of the product during film forming and having excellent ultraviolet ray absorbing ability, it is preferable to use a combination of an ultraviolet absorbent which is easy to evaporate during melt extrusion molding, It is preferable to use a UV absorber that is difficult to combine.

The ultraviolet absorbers X and Y preferably have a molecular weight of 500 to 1000, more preferably 550 to 700. If the molecular weight of the ultraviolet absorbers X and Y is too small, evaporation and scattering tend to occur during molding of the polarizer protective film. If the molecular weight is too large, compatibility with the thermoplastic resin tends to decrease.

The ultraviolet absorbers X and Y preferably have a molar extinction coefficient at the maximum absorption wavelength of 10 L / mol · cm or more, more preferably 15 L / mol · cm or more. When the molar extinction coefficients of the ultraviolet absorbers X and Y at the absorption maximum wavelengths are within the above ranges respectively, the ultraviolet absorptivity of the polarizer protective film is more excellent and the content of the ultraviolet absorber in the polarizer protective film is Can be reduced.

A commercially available ultraviolet absorber may be used. Commercially available triazine-based ultraviolet absorbers include, for example, " Kemisorb 102 " (2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy- (2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine), ADEKASTAB LAF70 manufactured by ADEKA Triazine), "adecastab LA46" (2- (4,6-diphenyl-1,3,5-triazin- Ethylhexanoyloxy) ethoxy) phenol) and "Chinuvin 1577" (2,4-diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) 5-triazine), and the like.

As commercially available benzotriazole ultraviolet absorbers, for example, "Adekastab LA31" (2,2'-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2,2'-methylenebis (4- (1,1,3,3-tetramethylbutyl) phenol) manufactured by KEMIPRO Corporation, (2- (2-hydroxy-5-methylphenyl) benzotriazole) and the like of Sumika-Chemex Co., .

The glass transition temperature of the resin composition comprising the resin (A) and the resin (B) is preferably 100 占 폚 or higher, more preferably 115 占 폚 or higher, and usually 180 占 폚 or lower. The glass transition temperature means an extrapolated glass transition intermediate temperature determined by a differential scanning calorimetry at a heating rate of 10 ° C / minute in accordance with JIS K7121: 1987. When the glass transition temperature of the resin composition is lower than 100 캜, it is difficult to suppress the shrinkage of the polarizer in a high temperature environment when the thermoplastic film is used as a polarizer protective film, and the polarizer is deformed or the polarizer protective film is peeled off from the polarizer It may be easy.

The melt mass flow rate (MFR) of the resin composition at 230 캜 and 37.3 N is preferably 0.8 g / 10 min to 10 g / 10 min, more preferably 0.9 g / 10 min to 8 g / 10 min More preferably 1.0 g / 10 min to 6 g / 10 min. When the MFR is larger than this range, stability of the discharge amount of the molten resin composition may be impaired when the thermoplastic resin film is produced by melt extrusion molding. When the MFR is smaller than this range, when the thermoplastic resin film is produced by melt extrusion molding, the molten resin composition does not spread uniformly in the T-die, and the thickness precision of the thermoplastic resin film may be lowered in some cases. The MFR can be measured according to JIS K7210 under the conditions of a measurement temperature of 230 占 폚 and a load of 37.3 N.

When the resin (A) further containing a cyclic acid anhydride monomer unit is used, it is preferable that the MFR is 1.2 g / 10 min or more, the occurrence of bubbles due to the cyclic acid anhydride monomer unit It is preferable from the viewpoint of being able to do.

The thickness of the thermoplastic resin film of the present invention is preferably 10 탆 to 1000 탆, more preferably 20 탆 to 500 탆, and still more preferably 20 탆 to 300 탆.

The thermoplastic resin film of the present invention preferably has a light transmittance at a wavelength of 260 nm in terms of a film thickness of 40 탆, preferably 2% or less, and a light transmittance at a wavelength of 380 nm in terms of a film thickness of 40 탆 Is less than 5%.

The thermoplastic resin film of the present invention is preferably a film having a single layer structure, but may be a film having a multilayer structure of two or more layers as long as the effect of the present invention is not impaired. When the thermoplastic resin film is a multilayer film, each layer may be formed of a resin composition having the same composition or may be formed of a resin composition of a different composition. The resin composition of the other composition means a resin composition containing different kinds of resins and different types of resins but different kinds of resins and different kinds of resins, do.

[The stretched film of the present invention]

The stretched film of the present invention is a film obtained by stretching the thermoplastic resin film of the present invention. Like the thermoplastic resin film of the present invention, the stretched film of the present invention is excellent in heat resistance and hardly shrinks in a high temperature environment, and is therefore excellent in mechanical strength because it is stretched.

Examples of the method for stretching the thermoplastic resin film of the present invention include a method of uniaxial stretching and a method of biaxial stretching. Among them, a biaxial stretching method is preferable. Examples of the biaxial stretching method include a biaxial stretching method and a simultaneous biaxial stretching method. Examples of the stretching direction include a machine direction of the thermoplastic resin film, and a direction orthogonal to the machine flow direction and a direction oblique to the machine flow direction. The stretching magnification is preferably 1.1 to 3 times. In the present specification, the machine direction is defined as a longitudinal direction, the longitudinal direction is defined as longitudinal stretching, and the direction orthogonal to the machine flow direction is defined as transverse direction and transverse direction is defined as transverse stretching. The direction of the machine flow refers to a direction in which the resin composition is transported while being formed into a film in a molten state in the case of producing an elongated thermoplastic resin film by melt extrusion molding.

The stretched film of the present invention may be subjected to a surface treatment. Examples of the surface treatment include hard coat treatment, antiglare treatment and antifouling treatment.

[Polarizer protective film]

The thermoplastic resin film of the present invention and the stretched film of the present invention are all suitable as a polarizer protective film. The polarizer protective film is a film used for protecting the polarizer by being disposed on one side of the polarizer. The thermoplastic resin film of the present invention and the stretched film of the present invention can be used not only for a polarizer protective film but also for a mining member for a building such as a window and a carport roofing material, a mining member for a vehicle such as a car window, a mining member for agriculture such as a greenhouse, A display member of a display, a decorating film may be laminated on a case of an electric appliance, a built-in vehicle, a building material for interior, a wallpaper, a veneer, a doorway, a window frame, a pedestal or the like.

[Polarizing plate]

The polarizing plate of the present invention is a polarizing plate in which the polarizer protective film of the present invention is disposed on at least one surface of a polarizer. It is preferable that the polarizer protective film and the polarizer are bonded. As the polarizer, a known polarizer can be mentioned. The thickness of the polarizer is usually from 5 탆 to 40 탆.

When the polarizer protective film is disposed on one surface of the polarizer, a transparent resin film may be disposed on the other surface. It is preferable that the transparent resin film and the polarizer are bonded. Examples of the transparent resin film include a triacetylcellulose film, a polycarbonate film, a polyethylene terephthalate film, an acrylic resin film, a laminated film of an acrylic resin and a polycarbonate resin, and an olefin resin film.

The polarizer protective film of the present invention and the polarizer are preferably bonded together with an adhesive. Prior to the bonding, it is preferable that at least one of the bonding surfaces is subjected to corona discharge treatment, plasma irradiation treatment, electron beam irradiation treatment or other surface activation treatment. The polarizer protective film of the present invention is excellent in adhesion strength when bonded to a polarizer by an adhesive as compared with a polarizer protective film comprising a methacrylic acid ester monomer unit and comprising a resin not containing an aromatic vinyl monomer unit.

The adhesive may be arbitrarily selected from those exhibiting an adhesive force with respect to each member. Typically, an aqueous adhesive, that is, an active energy ray-curable adhesive containing a component dissolving an adhesive component in water or dispersing an adhesive component in water, or a component cured by irradiation of an active energy ray can be exemplified. Above all, from the viewpoint of productivity, an active energy ray curable adhesive is preferable.

As the water-based adhesive, a composition using a polyvinyl alcohol-based resin or a urethane resin as a main component is preferable. When a polyvinyl alcohol-based resin is used as a main component of the water-based adhesive, examples of the polyvinyl alcohol-based resin include partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, as well as a carboxyl group-modified polyvinyl alcohol, an acetacetyl group-modified polyvinyl alcohol, And modified polyvinyl alcohol resins such as modified polyvinyl alcohol and amino group-modified polyvinyl alcohol. When a polyvinyl alcohol-based resin is used as an adhesive component, the adhesive is often prepared as an aqueous solution of a polyvinyl alcohol-based resin. The concentration of the polyvinyl alcohol-based resin in the aqueous adhesive solution is preferably 1 part by weight to 10 parts by weight, more preferably 1 part by weight to 5 parts by weight, based on 100 parts by weight of water.

In order to improve the adhesiveness, it is preferable to add a curing component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to an aqueous adhesive containing a polyvinyl alcohol resin as a main component. Examples of the water-soluble epoxy resin include polyamides obtained by reacting epichlorohydrin with polyamide polyamines obtained by reacting polyalkylene polyamines such as diethylene triamine and triethylene tetramine with dicarboxylic acids such as adipic acid And polyamine epoxy resins. As the polyamidepolyamine epoxy resin, commercially available products may be used. Examples thereof include "Sumirez Resin 650" and "Sumirez Resin 675" manufactured by DAOKAGAGAKU KABUSHIKI KAISHA, "WS-525" manufactured by Seiko PMC Corporation &Quot; and the like. The amount of the curable component or crosslinking agent added is preferably 1 part by weight to 100 parts by weight, more preferably 1 part by weight to 50 parts by weight, based on 100 parts by weight of the polyvinyl alcohol-based resin. When the addition amount is small, the adhesive property improving effect is small. On the other hand, when the addition amount is large, the adhesive layer may become fragile.

When a urethane resin is used as a main component of the water-based adhesive, a mixture of a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group can be mentioned as an example of a suitable adhesive composition. The polyester-based ionomer-type urethane resin is a urethane resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced into the urethane resin. The ionomeric urethane resin is preferably used as an aqueous adhesive since it emulsifies directly in water without using an emulsifier.

When an activating energy ray-curable adhesive is used, examples of the component (hereinafter, simply referred to as " curable component ") that is cured by irradiation of an active energy ray constituting the component are an epoxy compound, an oxetane compound, have. When a cationic polymerizable compound such as an epoxy compound or an oxetane compound is used, a cationic polymerization initiator is blended. When a radical polymerizable compound such as an acrylic compound is used, a radical polymerization initiator is added. Among them, an adhesive that makes the epoxy compound one of the curable components is preferable, and an adhesive that makes the alicyclic epoxy compound having an epoxy group directly bonded to the saturated carbon ring as one of the curable components is more preferable. Further, an oxetane compound may be used in combination therewith.

As the epoxy compound, a commercially available product may be used, and examples thereof include " Epikote " series manufactured by Mitsubishi Kagaku Kogyo Co., Ltd., " Epiclon " series manufactured by DIC K.K. "Adeka Resin" series manufactured by ADEKA, "DENARCOL" series manufactured by Nagase ChemteX Corporation, "DOWEXOX" series manufactured by DOW CHEMICAL Co., Ltd., Nissan Kagaku Kogyo Co., Ltd., And " Tepic " of the manufacture.

As the alicyclic epoxy compound to which the epoxy group is bonded directly to the saturated carbon ring, a commercially available product may be used. Examples of the alicyclic epoxy compound include " Cerocide " series and " Cyclomer " series manufactured by Gakkogou Kogyo Co., And " Sara Cure " series of manufacturing.

As the oxetane compound, a commercially available product may be used. Examples of the oxetane compound include "AARON oxetane" series manufactured by Toagosei Co., Ltd., "ETERNACOLL" series manufactured by UBE CORPORATION.

As the cationic polymerization initiator, commercially available products may be used, and examples thereof include " Kaya Cure " series manufactured by Nippon Kayaku Co., Ltd., " Sara Cure " series manufactured by Dow Chemical Co., TAZ "," BBI "and" DTS "manufactured by Midori Kagaku Kogyo Co., Ltd.," Adeka Optoma "series manufactured by ADEKA Corporation," RHODORSIL "series manufactured by Rhodia And the like.

The active energy ray-curable adhesive may contain a photosensitizer as required. By using the photosensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the cured layer can be further improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfates, redox compounds, azo and diazo compounds, anthracene compounds, halogen compounds, and photoreducation pigments.

Various kinds of additives may be added to the active energy ray-curable adhesive within a range that does not impair the adhesiveness thereof. Examples of the additive include an ion trap agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer and a defoaming agent. Further, a curing component which is cured by a reaction mechanism other than the cation polymerization may be added within a range not deteriorating the adhesiveness.

The active energy ray-curable adhesive may have the same composition or different compositions, but it is preferable to conduct the irradiation of active energy rays for curing both of them at the same time.

Examples of the active energy ray include X-rays, ultraviolet rays, visible rays, and the like. Among these, ultraviolet rays are preferable from the viewpoints of ease of use, ease of preparation of active energy ray-curable adhesive, stability, and curing performance. Examples of the ultraviolet light source include low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra high pressure mercury lamps, chemical lamps, black light lamps, microwave excited mercury lamps and metal halide lamps.

An active energy ray curable adhesive is applied to a polarizer or a polarizer protective film of the present invention to form a coated film, and the polarizer protective film of the present invention is polymerized through the formed film to form an active energy ray curable resin And the polarizer and the protective film of the present invention are bonded to each other to obtain the polarizing plate of the present invention.

The thickness of the adhesive layer obtained by using the active energy ray-curable adhesive is preferably 1 to 50 mu m, more preferably 1 to 10 mu m. The thickness of the adhesive layer can be adjusted by the thickness of the polarizer or the coating film formed on the polarizer protective film of the present invention.

The polarizing plate of the present invention can be a liquid crystal panel bonded to a liquid crystal cell and used in a liquid crystal display device. It is preferable that the polarizing plate and the liquid crystal cell are bonded to each other through a pressure-sensitive adhesive layer using a pressure-sensitive adhesive. The pressure-sensitive adhesive layer is generally formed of an acrylic pressure-sensitive adhesive containing acrylic acid ester as a main component and acrylic resin having a functional group-containing acrylic monomer copolymerized as a pressure-sensitive adhesive component. A liquid crystal panel in which a polarizing plate is bonded to a liquid crystal cell through a pressure-sensitive adhesive layer can be used for a liquid crystal display device.

Since the polarizer protective film of the present invention is made of the thermoplastic resin of the present invention or the stretched film of the present invention, the polarizer protective film is excellent in heat resistance and can suppress shrinkage of the polarizer even under a high temperature environment.

Example

Hereinafter, the present invention will be described in detail by way of examples.

The extrusion apparatus used in the examples and the comparative examples is the apparatus shown in Fig. 1, and the constitution is as follows.

Extruder: screw extruder having a screw diameter of 65 mm, uniaxial and vented (manufactured by Toshiba Machine Co., Ltd.).

T die: multi-manifold type die having a width of 800 mm and a lip interval of 1 mm (manufactured by Hitachi, Ltd.).

First cooling roll: Metal elastic roll

Second cooling roll: metal roll

Third cooling roll: metal roll

The metallic elastic roll was prepared by disposing a thin film made of stainless steel having a thickness of 2 mm in which one side was mirror-finished so as to cover the outer peripheral portion of the axial roll made of stainless steel so that the mirror finished surface became the outer surface of the roll, Is a metal elastic roll having an outer diameter of 250 mm, in which a fluid comprising a heating medium flow path is sealed. The metal roll is a spiral roll having an outer diameter of 250 mm, the surface of which is made of mirror-finished stainless steel.

[Thermoplastic resin]

The thermoplastic resins used in Examples 1 to 6 and Comparative Examples 1 to 5 will be described below. The weight average molecular weight (Mw) and number average molecular weight (Mn) of each resin were determined by gel permeation chromatography (GPC). On the other hand, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of Resin A1, Resin A2 and Resin C were determined in terms of polystyrene. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the resin B1 were determined in terms of polymethyl methacrylate.

Resin A1: A resin consisting of a methyl methacrylate monomer unit, a styrene monomer unit and a maleic anhydride monomer unit, which was prepared by copolymerizing methyl methacrylate, styrene and maleic anhydride.

The content of the methyl methacrylate monomer units was 20% by weight based on the total of 100% by weight of all the monomer units constituting the resin A1, the content ratio of the styrene monomer units was 65% by weight, the content of the maleic anhydride monomer units The ratio was 15% by weight.

The resin A1 had a weight average molecular weight (Mw) of 150,000, a number average molecular weight (Mn) of 68,000, and a Mw / Mn of 2.2.

Resin A2: A resin comprising a methyl methacrylate monomer unit, a styrene monomer unit, and a maleic anhydride monomer unit, which was prepared by copolymerizing methyl methacrylate, styrene and maleic anhydride.

The content of the methyl methacrylate monomer units was 26% by weight based on the total of 100% by weight of all the monomer units constituting the resin A2, the content of the styrene monomer units was 57% by weight, the content of the maleic anhydride monomer units The ratio was 17 wt%.

The weight average molecular weight (Mw) of resin A2 was 150,000, the number average molecular weight (Mn) was 66,000, and Mw / Mn was 2.3.

Resin C: A resin consisting of a methyl methacrylate monomer unit, a styrene monomer unit and a maleic anhydride monomer unit, and was prepared by copolymerizing methyl methacrylate, styrene and maleic anhydride.

The content of the methyl methacrylate monomer units was 39% by weight, the content of the styrene monomer units was 47% by weight, and the content of the maleic anhydride monomer units was 39% by weight based on the total 100% by weight of all the monomer units constituting the resin C. The ratio was 14% by weight.

Resin C had a weight average molecular weight (Mw) of 220,000, a number average molecular weight (Mn) of 83,000, and a Mw / Mn of 2.6.

Resin B1: Resin B1: a resin composed of a methyl methacrylate monomer unit and a methyl acrylate monomer unit, wherein methyl methacrylate and methyl acrylate are mixed with 100 parts by mass of a total of 100 parts by mass of all the monomer units constituting the resin B1, Of a UV absorbing agent having an absorption maximum at 300 nm and 342 nm ("Sumikabeck 200", manufactured by Sumika Chemtex Co., Ltd.) having a content of 97% by weight and a content of methyl acrylate monomer units of 3% Ltd.) at a concentration of 120 ppm, and melt-kneading the obtained resin composition with a twin-screw extruder.

Resin B1 had a weight average molecular weight (Mw) of 160,000, a number average molecular weight (Mn) of 85,000, and a Mw / Mn of 1.9.

[UV absorber]

Ultraviolet absorber X1, Y1 and Y2 described below were used as the ultraviolet absorber and the mixture was used so that the ultraviolet absorber X1: ultraviolet absorber Y1: ultraviolet absorber Y2 (weight ratio) was 0.7: 0.6: 1.2.

Ultraviolet absorber X1: Kemisorb 102 (absorption maximum: wavelength 280 nm, molar extinction coefficient 68.3 L / mol 占, m, weight average molecular weight: 508.9, triazine-based ultraviolet absorber) manufactured by KEMIPRO Co.,

Ultraviolet absorber Y1: Ultraviolet absorber "LAF70" (absorption maximum: wavelength 356 nm, molar absorptivity: 65.7 L / mol 占, m, weight average molecular weight: 699.9,

Ultraviolet absorber Y2: ultraviolet absorber Adekastab LA31 (absorption maximum: wavelength 350 nm, molar extinction coefficient 18.0 L / mol 占, m, weight average molecular weight 658, benzotriazole ultraviolet absorber) manufactured by ADEKA Co.,

Examples 1 to 6 and Comparative Examples 1 to 5

[Production of thermoplastic resin film]

An extruder, a T-die and first to third cooling rolls were arranged as shown in Fig. Subsequently, the resin composition obtained by mixing the resin A1, the resin A2 or the resin C, the resin B1, and the ultraviolet absorber in the ratios shown in Table 1 was melted and kneaded by an extruder, and each was supplied to a T die having a set temperature of 260 deg.

The film-shaped molten resin extruded from the T die was sandwiched between the first cooling roll and the second cooling roll arranged opposite to each other, and wound around a third cooling roll to be molded and cooled to obtain a thermoplastic resin film having a thickness of 120 占 퐉.

On the other hand, the surface temperature of the first cooling roll was 80 ° C, the surface temperature of the second cooling roll was 80 ° C, and the surface temperature of the third cooling roll was 100 ° C. These temperatures are values obtained by measuring the surface temperature of each cooling roll.

On the other hand, the amount of the resin A2, the resin B1 and the ultraviolet absorber to be used for 100 parts by weight of the total amount of the resin A2 and the resin B1 in Example 6 is about 25 parts by weight for the resin A2 and about 75 parts by weight , And the amount of ultraviolet absorber used is about 2.5 parts by weight.

MFR (measurement temperature 230 占 폚, load 37.3 N) of each resin composition was measured according to JIS K7210. Further, the glass transition temperature of each resin composition was measured. The results obtained are shown in Table 2.

In order to evaluate the impact resistance of each obtained thermoplastic resin film, the Charpy impact strength was measured by the following method and the pencil hardness was measured by the following method in order to evaluate the surface hardness. The results are shown in Table 3.

≪ Charpy impact strength &

The obtained thermoplastic resin film was cut in a width of 10 mm and measured according to JIS K7111-1.

<Pencil hardness>

And measured according to JIS K5600.

[Production of stretched film]

Each of the obtained thermoplastic resin films was biaxially stretched to prepare a stretched film. First, each thermoplastic resin film was passed through a pair of nip rolls provided before and after a hot-air circulation furnace to perform longitudinal stretching. , We used a furnace capable of setting the temperature divided into four zones of 1 m apart. And the second zone is then heated to a temperature equal to the glass transition temperature (Tg) of the resin composition used for preparing the thermoplastic resin film, and then the fourth zone at the third zone and the fourth zone at the exit side The zones were set at a temperature 10 DEG C higher than Tg, respectively. The length of the film passing through the nip roll on the inlet side was 2 mm / min, and the speed of the film passing through the nip roll on the outlet side was 4.4 mm / min. A film was produced.

Subsequently, the prepared longitudinally stretched film was cut so that the length in the longitudinal direction was 1 m to obtain a longitudinally stretched film having a length of 1 m, and the longitudinally stretched film having a length of 1 m in the longitudinal direction was stretched in the transverse direction And then stretched horizontally. The transverse stretching was carried out in a hot-air circulating furnace having a length of 4 m, and the internal temperature of the furnace was set to a temperature 10 캜 higher than Tg. , The speed at which it passes through the inside was 1 mm / min, and the draw ratio was doubled. Thus, a biaxially stretched film having a draw ratio of 2.2 in the longitudinal direction and a draw ratio of 2 in the transverse direction was obtained. The thickness of the obtained biaxially stretched film was 40 占 퐉.

&Lt; Handling property >

The handling property at the time of stretching of the thermoplastic film used for producing the stretched film was evaluated by the following method.

The longitudinally stretched film obtained by longitudinally stretching the thermoplastic resin film was cut to obtain 10 longitudinally stretched films having a length of 1 m in the longitudinal direction. The ten longitudinally stretched films thus obtained were transversely stretched to obtain ten biaxially stretched films. In the case of longitudinal stretching and transverse stretching, when the number of films broken by stretching was zero, it was judged that the handling property was good and evaluated as &amp; cir &amp;, and when one or more films were broken, , &Quot; The evaluation results are shown in Table 3.

[Production of Polarizer]

A polyvinyl alcohol film having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more and a thickness of 75 탆 was immersed in pure water at 30 캜 and then immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.02 / Immersed. Thereafter, the mixture was further immersed in an aqueous solution of 12/5/100 in weight ratio of potassium iodide / boric acid / water at 56.5 ° C. After the immersed film was washed with pure water at 8 캜, it was dried at 65 캜 to obtain a polarizer in which iodine was adsorbed and oriented on polyvinyl alcohol. The stretching was carried out mainly in the steps of iodine dyeing and boric acid treatment, and the total draw ratio was 5.3 times, and the thickness of the obtained polarizer was 27 mu m.

[Production of polarizer]

After the biaxially stretched film as a protective film was subjected to corona treatment on both sides of the obtained polarizer, the ultraviolet curing adhesive ("Aronix", manufactured by Toagosei Co., Ltd.) was applied, did. Thereafter, ultraviolet rays were irradiated to cure the adhesive to obtain a polarizing plate. On the other hand, ultraviolet rays were irradiated so that the accumulated light quantity in a wavelength range of 260 nm to 320 nm was 200 mJ / cm 2.

&Lt; Evaluation of mechanical strength in high temperature environment >

In order to evaluate the mechanical strength of the biaxially stretched film in a high temperature environment, the high temperature tensile modulus at 80 DEG C of the biaxially stretched film was measured by the following method. The higher the value, the better the strength of the polarizing film when it is bonded to the polarizer and the shrinkage of the polarizing film in the high temperature environment is high.

The biaxially stretched film was cut into a rectangular shape having a length of 120 mm in the longitudinal direction and a length of 25 mm in the transverse direction at a long side in the longitudinal stretching direction and stretched in the longitudinal direction at a stretching speed of 5 mm / Tensile test was performed. The high temperature tensile modulus was calculated from the stress-strain curve slope in the region where the tensile strength was 3 MPa to 6 MPa. The results are shown in Table 3.

<Evaluation of light transmittance>

The light transmittance of the biaxially stretched film at a wavelength of 260 nm and the light transmittance at a wavelength of 380 nm were measured using a spectrophotometer U-4100 manufactured by Hitachi High-Tech Fielding Co., Ltd. The results are shown in Table 3.

&Lt; Evaluation of Shrinkage Ratio of Polarizer &

From the polarizing plate of the polarizing plate manufactured by MD in the direction parallel to the stretching direction of the polarizing film and TD in the direction perpendicular to the stretching direction of the polarizing film, the length in the MD direction was 100 mm and the length in the TD direction was 100 mm The polarizer was cut off. The polarized plate thus cut was placed in an oven set at 80 DEG C and maintained for 250 hours. The polarizer was taken out and the length in the MD direction and the length in the TD direction were measured by Nogus, respectively, and the shrinkage rates in the MD and TD directions were calculated according to the following formula. The results are shown in Table 4.

Shrinkage percentage (%) = 100 占 100- (Length after heating at 80 占 폚 (mm)) / 100

&Lt; Evaluation of adhesive strength of polarizer &

The peeling strength between the polarizing film and the protective film in the polarizing plate was evaluated by the method described below.

The prepared polarizing plate was left for 300 hours, and cut into a rectangular shape of 200 mm x 25 mm in size. An acrylic pressure sensitive adhesive layer was provided on the surface of one protective film, and the pressure sensitive adhesive layer was bonded to the glass plate. A cutter blade was inserted between the protective film provided with the pressure-sensitive adhesive layer and the polarizing film, and 30 mm was peeled from the end in the longitudinal direction, and the peeled portion was held by the grip portion of the tester. The test piece in this state was tested at a grip moving speed of 300 mm in accordance with JIS K6854-2: 1999 "Adhesive-peel adhesion strength test method-Part 2: 180 degree peel" in an atmosphere of a temperature of 23 DEG C and a relative humidity of 55% / Min, and the average peel force across the length of 170 mm excluding the grip portion of 30 mm was obtained. The results are shown in Table 5.

[Thermoplastic resin]

The thermoplastic resins used in Examples 7 to 11 and Comparative Examples 6 to 8 will be described below. The weight average molecular weight (Mw) and number average molecular weight (Mn) of each resin were determined by gel permeation chromatography (GPC). On the other hand, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of Resin A3 and Resin A4 were determined in terms of polystyrene. The weight average molecular weight (Mw) and number average molecular weight (Mn) of Resin B2 were determined in terms of polymethyl methacrylate.

Resin A1: The same resin A1 as used in Examples 1 to 3 was used.

Resin A3: A resin consisting of a methyl methacrylate monomer unit, a styrene monomer unit and a maleic anhydride monomer unit, which was prepared by copolymerizing methyl methacrylate, styrene and maleic anhydride.

The content of the methyl methacrylate monomer units was 21% by weight based on the total 100% by weight of all the monomer units constituting the resin A3, the content of the styrene monomer units was 57% by weight, the content of the maleic anhydride monomer units The ratio is 22% by weight.

Resin A3 had a weight average molecular weight (Mw) of 193,000, a number average molecular weight (Mn) of 88,000, and a Mw / Mn of 2.2.

Resin A4: A resin comprising a methyl methacrylate monomer unit, a styrene monomer unit, and a maleic anhydride monomer unit, which was prepared by copolymerizing methyl methacrylate, styrene and maleic anhydride.

The content of the methyl methacrylate monomer units was 21% by weight based on the total of 100% by weight of all the monomer units constituting the resin A4, the content ratio of the styrene monomer units was 57% by weight, the content of the maleic anhydride monomer units The ratio is 22% by weight.

Resin A4 had a weight average molecular weight (Mw) of 127,000, a number average molecular weight (Mn) of 58,000, and a Mw / Mn of 2.19.

Resin B1: The same resin B1 as used in Examples 1 to 6 and Comparative Examples 3 to 5 was used.

Resin B2: a resin composed of a methyl methacrylate monomer unit and a methyl acrylate monomer unit, and is obtained by copolymerizing methyl methacrylate and methyl acrylate with a methyl methacrylate monomer unit based on 100% by weight of the total of all the monomer units constituting the resin B2 Of 99% by weight and a content of methyl acrylate monomer units of 1% by weight, and then an ultraviolet absorber &quot; SUMIBE 200 &quot; having an absorption maximum at 300 nm and 342 nm at a concentration of 100 ppm, and the obtained resin composition was melt-kneaded with a twin-screw extruder.

The resin B2 had a weight average molecular weight (Mw) of 101,000, a number average molecular weight (Mn) of 58,000 and a Mw / Mn of 1.8.

[Rubber elastomer particle]

As the rubber elastomer particles, the following rubber 1 and rubber 2 were used.

Rubber 1: "PARALOID ^™ EXL-2678" (butadiene rubber particle, powder type) manufactured by Dow Chemical Co., Ltd. was used. This rubber 1 has a refractive index of 1.516 and a particle diameter of 200 nm.

Rubber 2: Carnea M732 (butadiene rubber, powder type) manufactured by Kaneka Corporation was used. This rubber 2 has a refractive index of 1.515 and a particle diameter of 130 to 180 nm.

Examples 7 to 11 and Comparative Examples 6 to 8

[Production of thermoplastic resin film]

Resin A1, Resin A2, Resin A3, Resin A4, Resin B1, Resin B2, Rubber 1, Rubber 2 and ultraviolet absorber were mixed in the ratios shown in Table 6 to obtain a resin composition. On the other hand, only Y2 (adecastab LA31) was used as the ultraviolet absorber. A thermoplastic resin film was obtained using the obtained resin composition in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 5 by using the extruder, the T-die and the first to third cooling rolls shown in Fig. At this time, the thickness of the thermoplastic resin film was as shown in Table 8.

The results of measurement of the MFR and the glass transition temperature of each resin composition are shown in Table 7, and the Charpy impact strength of the obtained thermoplastic resin film is shown in Table 8. [ The bending property of the obtained thermoplastic resin film was evaluated by cutting a sample of the film into 10 mm x 50 mm and folding the long side direction in half to determine whether the film was not broken or not, &Quot; The results are shown in Table 8.

&Lt; Evaluation of mechanical strength in high temperature environment 2 >

As a second method for evaluating the mechanical strength of a thermoplastic resin film in a high temperature environment, a high temperature tensile modulus at 80 占 폚 of a thermoplastic resin film was measured by the following method.

The thermoplastic resin film was cut into a rectangular shape having a length of 100 mm in the longitudinal direction and a length of 25 mm in the transverse direction with a long side in the direction of extrusion. The tensile strength test was performed at 80 캜 at a tensile speed of 1 mm / I was. The high temperature tensile modulus was calculated from the stress-strain curve slope in the region where the tensile strength was 3 MPa to 6 MPa. The results are shown in Table 8.

<Evaluation of light transmittance 2>

As a second method for evaluating the light transmittance of the thermoplastic resin film, the light transmittance at a wavelength of 260 nm and the light transmittance at a wavelength of 380 nm were measured using a spectrophotometer UV-2450 manufactured by Shimadzu Corporation Respectively. The results are shown in Table 8.

[Production of stretched film]

The thermoplastic resin films obtained in Examples 7 and 8 were biaxially stretched under the same conditions as in Examples 1 to 6 and Comparative Examples 1 to 5, respectively, to prepare stretched films. The thickness of the obtained biaxially stretched film was 20 占 퐉. The handling properties of the thermoplastic resin films of Examples 7 and 8 were all good. The tensile modulus at high temperature of the stretched film after stretching was measured by the same method as that of the thermoplastic resin film before stretching. As a result, the stretched film of Example 7 was 1890 MPa and the stretched film of Example 8 was 1869 MPa.

[Production of Polarizer 2]

Polarizer 2 was produced in the same manner as in Polarizer 1 except that the thickness of the polyvinyl alcohol film was changed to 60 탆 and the total draw ratio was changed to 5.6 times. The thickness of the obtained polarizer 2 was 22 탆.

[Production of polarizer]

The thermoplastic resin films of Examples 7 to 11 and Comparative Examples 6 to 8 were each subjected to corona treatment on one side of the polarizer 2, and then an ultraviolet curing adhesive (Aronix, manufactured by Toagosei Co., Ltd.) A retardation film which was a biaxially stretched product of a cycloolefin resin and which had been previously subjected to a corona treatment on the joint surface was coated with another ultraviolet ray curable adhesive containing an epoxy compound as a main component on the other surface of the polarizer 2 to obtain a thermoplastic resin Film / polarizer / retardation film. Thereafter, ultraviolet rays were irradiated to cure the adhesive to obtain a polarizing plate. On the other hand, ultraviolet rays were irradiated so that the accumulated light quantity in a wavelength range of 260 nm to 320 nm was 200 mJ / cm 2.

&Lt; Evaluation of Shrinkage Ratio of Polarizer &

The obtained polarizing plate had a length in the MD direction of 100 mm and a length in the TD direction of 100 mm from the prepared polarizing plate in the direction perpendicular to the stretching direction of the polarizing film as TD and the direction parallel to the stretching direction of the polarizing film as TD A polarizer of 100 mm was cut out. The cut polarizing plate was placed in an oven at 80 DEG C and maintained for 250 hours. Dimensions before and after the oven injection were measured using a two dimensional measuring machine "NEXIV VMR-12072 " manufactured by Nikon Corporation. Then, the value obtained by the following formula was defined as the shrinkage percentage (%). The measurement results are shown in Table 9.

In Table 6, the amount of the resin A1, resin A2, resin A3, resin A4, resin B1, resin B2, rubber 1, rubber 2 and ultraviolet absorber (Y2) "(Part)".

The thermoplastic resin film of the present invention is excellent in heat resistance and hardly shrinks in a high temperature environment and is difficult to be broken by stretching. Thus, a stretched film obtained by stretching it is useful as a protective film of a polarizer.

1: extruder
2: Die
3: Film-type molten resin
4: Cooling unit
5: first cooling roll
6: Second cooling roll
7: Third cooling roll
A: Thermoplastic resin film

Claims (6)

(A) comprising a methacrylic acid ester monomer unit and an aromatic vinyl monomer unit, and a thermoplastic resin (A) comprising a resin composition containing a methacrylic acid ester monomer unit and a resin (B) containing no aromatic vinyl monomer unit As a film,
Wherein the resin (A) is a resin having an aromatic vinyl monomer unit content of 50 wt% or more based on 100 wt% of all the monomer units constituting the resin (A)
Wherein the resin (B) is a resin having a methacrylic acid ester monomer unit content of 50% by weight or more based on 100% by weight of all the monomer units constituting the resin (B)
Wherein the ratio (W _B / W _A ) of the weight (W _B ) of the resin (B) to the content (W _A ) of the methacrylic acid ester monomer units in the resin ( _A ) The thermoplastic resin film according to claim 1, wherein the resin composition further comprises rubber elastomer particles. The thermoplastic resin film according to claim 1 or 2, wherein the resin (A) further comprises a cyclic acid anhydride monomer unit and the melt mass flow rate of the resin composition is 1.2 g / 10 min or more . A stretched film obtained by stretching the thermoplastic resin film according to any one of claims 1 to 3. A polarizer protective film comprising the thermoplastic resin film according to any one of claims 1 to 3 or the stretched film according to claim 4. Wherein the polarizer protective film according to claim 5 is disposed on at least one surface of the polarizer.

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