JP6359579B2 - Resin film - Google Patents

Description

  The present invention relates to a resin film, and more particularly to a polarizer protective film and a polarizing plate.

  A polarizing plate is usually used for a liquid crystal display device, and the polarizing plate is usually protected on at least one surface of a polarizer made of a polyvinyl alcohol resin to which a dichroic dye is adsorbed and oriented. For this purpose, a polarizer protective film is disposed.

  As a polarizer protective film, in addition to a triacetyl cellulose resin, a film made of a resin such as an acrylic resin is also widely known. For example, Patent Document 1 discloses a resin containing maleic anhydride as a monomer unit as a resin that can be used as a polarizer protective film.

JP 2014-65805 A

  However, when a resin containing a cyclic acid anhydride such as maleic anhydride as a monomer unit as described in Patent Document 1 is used, the resin is heated to a molten state, and this is formed into a film. In some cases, extremely small bubbles were generated in the resin film obtained. A resin film in which such bubbles are generated is not desirable in terms of appearance.

  Then, an object of this invention is to provide the resin film with a favorable external appearance. Another object of the present invention is to provide a polarizer protective film comprising this resin film, a polarizing plate comprising this polarizer protective film, and a method for producing this resin film.

The present invention provides the following preferred embodiments.
[1] A resin film comprising a thermoplastic resin composition containing a polymer (A) containing a cyclic acid anhydride monomer unit,
The melt mass flow rate of the thermoplastic resin composition is 2.5 g / 10 min or more,
The resin film which contains the component which has a decarboxylation catalyst function with respect to the said cyclic acid anhydride monomer unit in the quantity which does not express the said decarboxylation catalyst function.
[2] The resin film according to [1], wherein a content of the cyclic acid anhydride monomer unit in the thermoplastic resin composition is 3% by weight or more based on the thermoplastic resin composition.
[3] The resin film according to [1] or [2], including a metal element as a component exhibiting the decarboxylation catalytic action.
[4] The resin film according to [3], including an alkali metal element as the metal element.
[5] The resin film according to [4], wherein the content of the alkali metal element in the thermoplastic resin composition is 20 ppm or less.
[6] The resin film according to [3], including an alkaline earth metal element as the metal element.
[7] The resin film according to [6], wherein the content of the alkaline earth metal element in the thermoplastic resin composition is 500 ppm or less.

[8] The resin film according to any one of [1] to [7], wherein the amount of CO ₂ generated per 1 g of the resin film between 150 ° C. and 300 ° C. is 0.29 mg or less.
[9] The resin film according to any one of [1] to [8], wherein the thermoplastic resin composition further includes a methacrylic acid ester polymer (B) having a melt mass flow rate of 3 g / 10 min or more.
[10] The resin film according to any one of [1] to [9], wherein the thermoplastic resin composition further contains 5% by weight to 40% by weight of rubber elastic particles.
[11] The resin film according to [10], wherein a 1% weight reduction temperature of the rubber elastic particles is 305 ° C or higher.
[12] The method for producing a resin film according to any one of [1] to [11], wherein the thermoplastic resin composition is melt-kneaded at a melting temperature of 230 ° C. or higher and 280 ° C. or lower and formed into a film shape.
[13] The method for producing a resin film according to any one of [1] to [11], wherein the thermoplastic resin composition is melt-kneaded for a residence time of 60 minutes or less and formed into a film shape.
[14] A polarizer protective film comprising the resin film according to any one of [1] to [11].
[15] A polarizing plate in which the polarizer protective film according to [14] is disposed on at least one surface of the polarizer.
[16] A thermoplastic resin composition containing a polymer (A) containing a cyclic acid anhydride monomer unit,
The melt mass flow rate of the thermoplastic resin composition is 2.5 g / 10 min or more,
A thermoplastic resin composition comprising a component having a decarboxylation catalyst function for the cyclic acid anhydride monomer unit in an amount that does not exhibit the decarboxylation catalyst function.

  According to the present invention, a resin film having a good appearance can be provided. Moreover, the polarizer protective film which consists of such a resin film, and the polarizing plate containing this can also be provided. Furthermore, the method of manufacturing this resin film can also be provided.

It is a schematic explanatory drawing which shows the manufacturing method of the resin film of this invention.

  The resin film of the present invention is a film made of a thermoplastic resin composition containing a polymer (A) containing a cyclic acid anhydride monomer unit. In other words, the resin film of the present invention is a cyclic acid anhydride. Containing at least a polymer (A) containing a monomer unit.

[Thermoplastic resin composition]
The thermoplastic resin composition contains a polymer (A) containing a cyclic acid anhydride monomer unit, and optionally the following polymer (B), rubber elastic particles and / or other components. . The resin film of the present invention includes a component constituting a thermoplastic resin composition, that is, a polymer (A) containing a cyclic acid anhydride monomer unit, and optionally the following polymer (B), rubber elasticity Contains body particles and / or other components.

（式中、Ｒ^１およびＲ^２は、それぞれ独立して、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基またはフェニル基を表す。）
で表される環状酸無水物単量体単位が挙げられる。 [Polymer A]
The polymer (A) is a polymer containing a cyclic acid anhydride monomer unit. The cyclic acid anhydride monomer unit is derived from a cyclic acid anhydride monomer. Specific examples of the cyclic acid anhydride monomer unit include the following formula (1):

(In the formula, R ¹ and R ² each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a phenyl group.)
The cyclic acid anhydride monomer unit represented by these is mentioned.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. Examples of the alkyl group having 1 to 12 carbon atoms include linear or branched groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, and 2-ethylhexyl group. A branched alkyl group is exemplified, an alkyl group having 1 to 8 carbon atoms is preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, and a methyl group is further preferable.

R ¹ and R ² are preferably a hydrogen atom. R ¹ and R ² may be the same as or different from each other.

  Examples of cyclic acid anhydride monomers include maleic anhydride, citraconic anhydride, dimethyl maleic anhydride, dichloromaleic anhydride, bromomaleic anhydride, dibromomaleic anhydride, phenylmaleic anhydride, and diphenylmaleic anhydride. Maleic anhydride is preferred. Two or more cyclic acid anhydride monomers may be used in combination.

  The content of the cyclic acid anhydride monomer unit in the polymer (A) is 100% by weight of all monomer units constituting the polymer (A) in terms of transparency and heat resistance of the polymer (A). %, Preferably 5% to 35% by weight, more preferably 10% to 30% by weight, and still more preferably 15% to 25% by weight.

  The content of the cyclic acid anhydride monomer unit in the thermoplastic resin composition is preferably 3% by weight or more, more preferably 4% by weight or more, and even more preferably 5% by weight or more, based on the thermoplastic resin composition. It is preferably 30% by weight or less, more preferably 25% by weight or less, still more preferably 20% by weight or less, for example 10% by weight or less, particularly 8% by weight or less. When the content of the cyclic acid anhydride monomer unit in the thermoplastic resin composition is not less than the above lower limit, the heat resistance of the resin film is improved and the appearance of the resin film is further improved. When the content of the cyclic acid anhydride monomer unit in the thermoplastic resin composition is not more than the above upper limit value, bubbles are hardly generated during molding of the resin film.

  The polymer (A) preferably contains a methacrylic acid ester monomer unit in addition to the cyclic acid anhydride monomer unit, and more preferably contains an aromatic vinyl monomer unit. When the polymer (A) contains a methacrylic acid ester monomer unit, the toughness of the resulting resin film can be improved. When the polymer (A) contains an aromatic vinyl monomer unit, the reactivity of the cyclic acid anhydride monomer can be improved when the polymer (A) is synthesized.

  A 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-butyl methacrylate, 2-ethylhexyl methacrylate, Examples thereof include C1-C8 alkyl or cycloalkyl ester monomers of methacrylic acid such as cyclohexyl methacrylate. Two or more methacrylate monomers may be used in combination. Especially, the C1-C7 alkylester monomer of methacrylic acid is preferable, and methyl methacrylate is more preferable at the heat resistance of a polymer (A) and a transparency point.

  The content of the methacrylic acid ester monomer unit in the polymer (A) is 100% by weight with respect to all the monomer units constituting the polymer (A) in terms of the transparency of the polymer (A). The content is preferably 5% to 40% by weight, more preferably 5% to 35% by weight, still more preferably 5% to 30% by weight, and particularly preferably 5% to 25% by weight.

（式中、Ｒ^３およびＲ^４は、それぞれ独立して、水素原子、ハロゲン原子、ヒドロキシル基、アルコキシ基、ニトロ基または炭素数１〜１２のアルキル基を表し、ｎは１〜３の整数を表す。）
で表される単量体単位が挙げられる。 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 a substituted vinyl group is bonded to an aromatic ring. Specific examples of the aromatic vinyl monomer unit include the following formula (2):

(Wherein R ³ and R ⁴ 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) Represents.)
The monomer unit represented by these is mentioned.

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

R ³ is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms (particularly an alkyl group having 1 to 8 carbon atoms, especially an alkyl group having 1 to 4 carbon atoms), more preferably a hydrogen atom or a methyl group. R ⁴ is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms (particularly an alkyl group having 1 to 8 carbon atoms, especially an alkyl group having 1 to 4 carbon atoms), more preferably a hydrogen atom. n is preferably 1. R ³ and R ⁴ may be the same as or different from each other.

  Examples of the aromatic vinyl monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 2-methyl-4-chlorostyrene, 2,4,6-trimethylstyrene, α-methylstyrene, cis-β-methylstyrene, trans-β-methylstyrene, 4-methyl-α-methylstyrene, 4-fluoro-α-methylstyrene, 4-chloro- α-methylstyrene, 4-bromo-α-methylstyrene, 4-tert-butylstyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene, 2,4-difluorostyrene, 2-chlorostyrene, 3- Chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, 2- Lomostyrene, 3-bromostyrene, 4-bromostyrene, 2,4-dibromostyrene, α-bromostyrene, β-bromostyrene, 2-hydroxystyrene, 4-hydroxystyrene, and the like. preferable. Two or more aromatic vinyl monomers may be used in combination.

  The content of the aromatic vinyl monomer unit in the polymer (A) is preferably 50% by weight or more with respect to 100% by weight of all the monomer units constituting the polymer (A). Since the resin film of this invention contains such a polymer (A) in the said range, it becomes a resin film excellent in the point of the dimensional stability in a high temperature environment. The content of the aromatic vinyl monomer unit in the polymer (A) is preferably 50% by weight to 80% by weight in terms of transparency, heat resistance and dimensional stability in a high temperature environment of the resin film of the present invention. %, More preferably 52% to 78% by weight, still more preferably 55% to 75% by weight.

  As long as the polymer (A) does not impair the effects of the present invention, the above-mentioned monomer units other than the cyclic acid anhydride monomer unit, the methacrylic acid ester monomer unit and the aromatic vinyl monomer unit are used. The monomer unit may be included. The monomer unit other than the monomer unit described above is a monomer unit derived from a monomer that can be copolymerized with at least one of the monomers derived from the monomer unit described above. The monomer unit is preferably a monomer unit derived from a monomer copolymerizable with all of the monomers derived from the above-described three types of monomer units. The content of monomer units other than the above-described monomer units is preferably 50% by weight or less, more preferably 100% by weight or less, more preferably 100% by weight of all monomer units constituting the polymer (A). It is 30 weight% or less, More preferably, it is 10 weight% or less. The lower limit of the content of monomer units other than the monomer units described above is, for example, 0% by weight or more.

  The weight average molecular weight Mw of the polymer (A) is preferably 90,000 to 300,000, more preferably 100,000 to 250,000, from the viewpoint of the handleability of the film during molding of the resin film of the present invention or when the resin film of the present invention is stretched. More preferably, it is 110000-200000. In the present invention, the weight average molecular weight Mw and the number average molecular weight Mn of the polymer (A) can be measured in terms of polymethyl methacrylate by gel permeation chromatography (GPC) measurement, for example.

  The number average molecular weight Mn of the polymer (A) is preferably from 35,000 to 80,000, more preferably from 40000 to 70000, from the viewpoint of film handling properties during molding of the resin film of the present invention or stretching of the resin film of the present invention. More preferably, it is 450,000 to 600,000.

  The molecular weight distribution Mw / Mn of the polymer (A) is preferably 1.3 to 4, more preferably 1.5 to 3.5, and still more preferably 1.7 to 3 from the viewpoint of moldability of the resin film. is there.

  The melt mass flow rate (MFR) of the polymer (A) is 1 g / 10 min or more, preferably 1.3 g / 10 min or more, more preferably 1.5 g / 10 min or more, preferably 10 g / 10 min or less, more preferably It is 8 g / 10 min or less, more preferably 7 g / 10 min or less. When the MFR of the polymer (A) is equal to or higher than the above lower limit value, when a resin film is produced by melt extrusion, the decarboxylation reaction caused by the cyclic acid anhydride monomer unit during melt kneading can be suppressed. it can. When the MFR of the polymer (A) is not more than the above upper limit, the stability of the discharge amount of the molten thermoplastic resin composition is good when a resin film is produced by melt extrusion molding. In the present invention, MFR can be measured according to JIS K7210 under the conditions of a measurement temperature of 230 ° C. and a load of 37.3 N.

  The polymer (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, or a cast polymerization method. The content of each monomer unit in the polymer (A) can be adjusted by changing the amount of the monomer used.

  The content of the polymer (A) in the thermoplastic resin composition is preferably 10% by weight to 80% by weight, more preferably 15% by weight to 75% by weight, further based on the total amount of the thermoplastic resin composition. Preferably, it is 20% by weight to 70% by weight. When the content of the polymer (A) in the thermoplastic resin composition is within the above range, since the heat resistance is further improved, a resin film having a good appearance can be obtained.

[Polymer (B)]
In order to adjust the melt mass flow rate of the thermoplastic resin composition, the thermoplastic resin composition may contain a polymer (B) in addition to the polymer (A). The polymer (B) is a resin containing a methacrylic acid ester monomer unit and no aromatic vinyl monomer unit.

  Examples of the methacrylic acid ester monomer for deriving the methacrylic acid ester monomer unit include those described above for the polymer (A), and methyl methacrylate is preferred. Two or more methacrylate ester monomer units may be included.

  From the viewpoint of compatibility of the resin and transparency of the resin film, the methacrylic acid ester monomer unit in the polymer (A) and the methacrylic acid ester monomer unit in the polymer (B) are the same. To preferred.

  The content of the methacrylic acid ester monomer unit in the polymer (B) is usually 50% by weight or more, preferably 70% by weight with respect to 100% by weight of all the monomer units constituting the polymer (B). As mentioned above, More preferably, it is 90 weight% or more, More preferably, it is 92 weight% or more.

The polymer (B) is a resin that does not contain an aromatic vinyl monomer unit, that is, a resin in which the content of the aromatic vinyl monomer unit is 0 (zero)% by weight. Other monomer units other than the unit and the aromatic vinyl monomer unit may be included. Examples of other monomers include acrylate esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and the like. Monomer;
Unsubstituted or substituted styrene monomers such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, 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;
Examples include cyclic imide monomers such as phenylmaleimide and cyclohexylmaleimide, and acrylate monomers are preferred. In particular, the polymer (B) more preferably contains monomer units derived from two or more kinds of acrylate monomers, and in such a case, the resin film has high transparency and thermal decomposition resistance. However, it becomes easy to adjust the MFR at the same time.

  The weight average molecular weight of the polymer (B) is preferably 40,000 to 200,000, more preferably 50,000 to 150,000, and still more preferably 60000 to 90,000 in view of increasing MFR. In the present invention, the weight average molecular weight Mw and the number average molecular weight Mn of the polymer (B) can be measured in terms of polymethyl methacrylate by gel permeation chromatography (GPC) measurement, for example.

  The number average molecular weight Mn of the polymer (B) is preferably from 20,000 to 100,000, more preferably from 30,000 to 70,000, and even more preferably from 35,000 to 50,000, in view of increasing the MFR.

  From the viewpoint of moldability of the resin film, the molecular weight distribution Mw / Mn of the polymer (B) is preferably 1.3 to 4, more preferably 1.5 to 3.5, and even more preferably 1.7 to 3. is there.

  The MFR of the polymer (B) is preferably 3 g / 10 min or more, more preferably 5 g / 10 min or more, still more preferably 6.5 g / 10 min or more. When the MFR of the polymer (B) is equal to or higher than the lower limit, the MFR of the thermoplastic resin composition can be easily adjusted. In addition, the upper limit of MFR of a polymer (B) is 40 g / 10min or less normally from a viewpoint of granulation property.

  The polymer (B) is a known monomer such as a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, or a cast polymerization method. It can manufacture by polymerizing by a method.

  The content of the polymer (B) in the thermoplastic resin composition is preferably 20% by weight or more, more preferably 30% by weight or more, preferably 80% by weight, based on the total amount of the thermoplastic resin composition. Hereinafter, it is more preferably 70% by weight or less. When the content of the polymer (B) is not less than the above lower limit, the MFR of the thermoplastic resin composition can be easily adjusted. When the content of the polymer (B) is not more than the above upper limit, the heat resistance can be further improved and a resin film having a good appearance can be obtained.

[Rubber elastic particles]
In one embodiment of the present invention, from the viewpoint of improving the toughness, impact resistance and film-forming property of the resin film, the thermoplastic resin composition constituting the resin film may further contain rubber elastic particles. The rubber elastic particles are particles including a rubber elastic body layer exhibiting rubber elasticity. For example, the rubber elastic particles may be a single-layered particle including only a rubber elastic body layer exhibiting rubber elasticity, or rubber elasticity exhibiting rubber elasticity. It may be a multi-layered particle (core-shell type particle) having another layer together with the body layer. Examples of the rubber elastic body constituting the rubber elastic body layer include an olefin elastic polymer, a diene elastic polymer, a styrene-diene elastic copolymer, an acrylic elastic polymer, and the like. Examples of the olefin-based elastic polymer include a polypropylene-based polymer and a polyethylene-based polymer. Examples of the diene-based elastic polymer include butadiene rubber and isoprene rubber. A styrene-diene-based elastic copolymer. Examples thereof include a styrene-butadiene copolymer, and examples of the acrylic elastic polymer include a polymer or a copolymer mainly composed of an acrylate ester.

  The particle diameter of the rubber elastic particles is, for example, 50 nm or more, preferably 0.1 μm or more, for example, 0.8 μm or less, preferably 0.5 μm or less. When the particle diameter of the rubber elastic particles is equal to or larger than the lower limit, the fluidity is hardly lowered when the thermoplastic resin composition is processed into a film. When the particle diameter of the rubber elastic particles is not more than the above upper limit value, the internal haze of the thermoplastic resin composition is unlikely to increase. The particle diameter of the rubber elastic particles can be measured as a number average molecular weight by observation with an electron microscope, and can be calculated, for example, as an average value of 100 rubber elastic particles.

  The content of the rubber elastic body particles in the thermoplastic resin composition is preferably 5% by weight or more, preferably 7% by weight or more, more preferably 10% by weight with respect to 100% by weight of the total amount of the thermoplastic resin composition. Above, preferably 40% by weight or less, more preferably 35% by weight or less, and further preferably 25% by weight or less. When the content of the elastic rubber particles in the thermoplastic resin composition is not less than the above lower limit, the brittleness of the resulting resin film can be improved. When the content of the elastic rubber particles in the thermoplastic resin composition is not more than the above upper limit value, the heat resistance of the resin film is further improved, so that a resin film having a good appearance can be obtained.

  The 1% weight loss temperature of the rubber elastic particles is preferably 305 ° C. or higher, more preferably 310 ° C. or higher, and further preferably 315 ° C. or higher. When the 1% weight loss temperature of the rubber elastic particles is equal to or higher than the lower limit, the rubber elastic particles have good heat resistance, and the rubber elastic particles are hardly decomposed during melt-kneading and suppress foaming in the resin film. be able to. The upper limit of the 1% weight reduction temperature of the rubber elastic particles is, for example, 500 ° C. or less.

  The 1% weight loss temperature can be measured by differential thermal / thermogravimetric analysis (TG-DTA). In the measurement, after the rubber elastic particles were previously dried at 80 ° C. for 12 hours or more, the weight reduction amount of the rubber elastic particles when the temperature was increased at a rate of 10 ° C./min in a nitrogen atmosphere was the total weight. This is the temperature at 1%.

  The rubber elastic particles may contain a metal element in the process of producing the rubber elastic particles. This metal element may cause a decarboxylation function of the cyclic acid anhydride monomer. For this reason, it is preferable that the metal element contained in the rubber elastic particles is an amount that does not exhibit the decarboxylation function. For example, the alkali metal element contained in the rubber elastic particles is preferably 100 ppm or less. Further, the alkaline earth metal element is preferably 1000 ppm or less. In order to reduce the metal component in the rubber elastic particles, for example, it is possible to increase the washing step, or to select a material that does not contain a metal component for the emulsifier and the polymerization initiator added at the time of production.

[Other ingredients]
In the present invention, the thermoplastic resin composition may contain components other than the polymer (A), the polymer (B), and rubber elastic particles. Other components include light diffusing agents, matting agents, dyes, light stabilizers, ultraviolet absorbers, antioxidants, mold release agents, flame retardants, antistatic agents, lubricants and other resins (polymer (A And resins other than the polymer (B)).

  In a preferred embodiment of the present invention, the thermoplastic resin composition may contain an ultraviolet absorber, and preferably an ultraviolet absorber having an absorption maximum at a wavelength of 200 to 320 nm (hereinafter referred to as an ultraviolet absorber X). And an ultraviolet absorber having 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 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, and a benzotriazole ultraviolet ray having an absorption maximum at a wavelength of 200 to 320 nm. Examples thereof include an absorbent, a benzoate 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.

Examples of the ultraviolet absorber X include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-). Ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-) Butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,6-diphenyl-4- (2- Hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, , 4-Diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1,3 , 5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-N-octyloxyphenyl) -1,3,5-triazine, 2- (4,6- Diphenyl-1,3,5-triazin-2-yl) -5- (2- (2-ethylhexanoyloxy) 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,
2,4-di-tert-butylphenyl 3 ′, 5′-di-tert-butyl-4′-hydroxybenzoate, 2,6-di-tert-butylphenyl 3 ′, 5′-di-tert-butyl- 4′-hydroxybenzoate, n-hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, n-octadecyl 3,5-di-tert-butyl-4-hydroxybenzoate,
Examples include 2-ethylhexyl 2-cyano-3,3-diphenyl acrylate and ethyl 2-cyano-3- (3,4-methylenedioxyphenyl) acrylate.

  Examples of the ultraviolet absorber Y include a triazine 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 having an absorption maximum at a wavelength of 320 to 400 nm. An absorbent is mentioned.

  Examples of the ultraviolet absorber Y include 2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine, 2,2′-dihydroxy-4-methoxybenzophenone. 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-3-tert-butyl- 5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3- (3,4,5,6) -Tetrahydrophthalimidomethyl) -5-methylphenyl) benzotriazole, 2,2'-methylenebis (4- (1,1,3,3-te Lamethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, and 2- (2- And hydroxy-3,5-di-tert-amylphenyl) -5-chlorobenzotriazole.

  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 and the ultraviolet absorber Y having a similar structure may be used in combination, or the ultraviolet absorber X and the ultraviolet absorber Y having no similar structure may be used in combination. UV absorbers that are easy to evaporate during melt extrusion molding and transpiration during melt extrusion molding in that the resin film with excellent UV absorption ability is obtained with little contamination around the molding machine due to evaporates during film molding. It is preferable to use in combination with a difficult ultraviolet absorber.

  The ultraviolet absorbers X and Y each preferably have a molecular weight of 500 to 1000, and more preferably 550 to 700. If the molecular weights of the ultraviolet absorbers X and Y are too small, they tend to evaporate during the formation of the polarizer protective film, and if the molecular weight is too large, the compatibility with the thermoplastic resin tends to decrease.

  The ultraviolet absorbers X and Y each preferably have a molar extinction coefficient at the absorption maximum wavelength of 10 L / mol · cm or more, and more preferably 15 L / mol · cm or more. When the molar extinction coefficient at the wavelength of the absorption maximum of the ultraviolet absorbers X and Y is in the predetermined range, the ultraviolet absorbing ability of the resin film (particularly, the polarizer protective film) becomes more excellent. The content of the ultraviolet absorbent in the resin film (particularly, the polarizer protective film) can be reduced.

A commercially available ultraviolet absorber may be used. As a commercially available triazine-based ultraviolet absorber, for example, “Kemisorb 102” (2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-N-octyloxyphenyl) manufactured by Chemipro Kasei Co., Ltd.) -1,3,5-triazine), “ADEKA STAB LAF70” (2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine, manufactured by ADEKA Corporation ), “Adekastab LA46” (2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (2- (2-ethylhexanoyloxy) ethoxy) phenol), and BASF “Tinuvin 1577” (2,4-diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3, manufactured by Japan Co., Ltd. 5-triazine).
As a commercially available benzotriazole ultraviolet absorber, for example, “ADEKA STAB LA31” (2,2′-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H— Benzotriazol-2-yl) phenol), “Kemisorb 279” (2,2′-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole) manufactured by Chemipro Kasei Co., Ltd. 2-yl) phenol) and “Sumisorb 200” (2- (2-hydroxy-5-methylphenyl) benzotriazole) manufactured by Sumika Chemtex Co., Ltd., and the like.

  The glass transition temperature of the thermoplastic resin composition in the present invention is preferably 100 ° C. or higher, more preferably 115 ° C. or higher, and usually 180 ° C. or lower. The glass transition temperature means an extrapolated glass transition intermediate temperature obtained at a heating rate of 10 ° C./min by differential scanning calorimetry according to JIS K7121: 1987. When the glass transition temperature of the thermoplastic resin composition is equal to or higher than the above lower limit, when the resin film is used as a polarizer protective film, shrinkage of the polarizer is suppressed in a high temperature environment, and the polarizing plate is hardly deformed. The polarizer protective film is difficult to peel off from the polarizer. In addition, the upper limit of the glass transition temperature of a thermoplastic resin composition is 300 degrees C or less, for example.

  The melt mass flow rate (MFR) of the thermoplastic resin composition is 2.5 g / 10 min or more, preferably 3 g / 10 min or more, more preferably 3.5 g / 10 min or more, further preferably 4 g / 10 min or more, preferably It is 10 g / 10 min or less, more preferably 8 g / 10 min or less, and further preferably 6 g / 10 min or less. If the MFR of the thermoplastic resin composition is less than 2.5 g / 10 min, bubbles are easily generated in the resin film, which is not preferable in terms of appearance, and the image display function of an image display element using such a resin film is lowered. obtain. When the MFR of the thermoplastic resin composition is not less than the above lower limit, when a resin film is produced by melt extrusion, the decarboxylation reaction caused by the cyclic acid anhydride monomer unit during melt kneading can be suppressed. it can. When the MFR of the thermoplastic resin composition is not more than the above upper limit value, when the resin film is produced by melt extrusion molding, the stability of the discharge amount of the molten thermoplastic resin composition is good. In addition, MFR of a thermoplastic resin composition can be adjusted by controlling the number average molecular weight, the weight average molecular weight, molecular weight distribution, etc. of the polymer (A) which comprises a thermoplastic resin composition, for example. The number average molecular weight, weight average molecular weight and molecular weight distribution of the polymer (A) can be controlled, for example, by selecting a polymerization condition (a polymerization catalyst such as a living polymerization catalyst, a polymerization temperature, a polymerization time, and an additive). Moreover, MFR of a thermoplastic resin composition can also be adjusted by adding a polymer (B) to a thermoplastic resin composition. The MFR of the polymer (B) can be performed in the same manner as the adjustment of the MFR of the polymer (A). MFR can be measured in accordance with JIS K7210 under the conditions of a measurement temperature of 230 ° C. and a load of 37.3 N.

  A thermoplastic resin composition contains the component which has a decarboxylation catalyst function with respect to a cyclic acid anhydride monomer unit in the quantity which does not express the said decarboxylation catalyst function. Examples of the component having a decarboxylation catalyst function include metal elements. Examples of metal elements include alkali metal elements and alkaline earth metal elements. In the present invention, when the thermoplastic resin composition contains rubber elastic particles, it has been found that an alkali metal element and an alkaline earth metal element can be mixed, and further, these metal elements are contained in the polymer (A). It has also been found that it can contribute to the degradation reaction. Thereby, in the thermoplastic resin composition, it is preferable that the component having a decarboxylation catalyst function with respect to the cyclic acid anhydride monomer unit, such as an alkali metal element and an alkaline earth metal element, is in a specific range. It becomes one characteristic for manufacturing the resin film which has.

  Examples of the alkali metal element include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr), particularly sodium (Na) and potassium (K ). The concentration of the alkali metal element contained in the thermoplastic resin composition is preferably 18 ppm or less, more preferably 15 ppm or less, and even more preferably 10 ppm or less. If the concentration of the alkali metal element contained in the thermoplastic resin composition is not more than the above upper limit value, the resulting resin film is excellent in heat resistance, so that foaming is suppressed and a resin film excellent in appearance can be obtained. . In addition, the minimum value of the density | concentration of the alkali metal element contained in a thermoplastic resin composition is 1 ppm or more, for example. When the concentration of the alkali metal element contained in the thermoplastic resin composition is 1 ppm or more, a resin film in which foaming is suppressed can be obtained and industrially advantageous.

  Examples of the alkaline earth metal element include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra), and particularly magnesium (Mg) and calcium. (Ca). The concentration of the alkaline earth metal element contained in the thermoplastic resin composition is preferably 500 ppm or less, more preferably 300 ppm or less, and even more preferably 150 ppm or less. When the concentration of the alkaline earth metal element contained in the thermoplastic resin composition is not more than the above upper limit, foaming is further suppressed, so that a resin film excellent in appearance can be obtained. In addition, the minimum value of the density | concentration of the alkaline-earth metal element contained in a thermoplastic resin composition is 1 ppm or more, for example. When the concentration of the alkaline earth metal element contained in the thermoplastic resin composition is 1 ppm or more, a resin film in which foaming is suppressed can be obtained and industrially advantageous. Examples of the method for reducing the content of metal elements such as alkali metal elements and alkaline earth metal elements in the thermoplastic resin composition include, for example, increasing the cleaning process of components constituting the thermoplastic resin composition, This can be achieved by selectively using raw materials that do not contain (e.g., emulsifiers and polymerization initiators).

As described above, when the thermoplastic resin contains a cyclic acid anhydride monomer unit such as maleic anhydride, CO ₂ bubbles are generated by a decarboxylation reaction in which the cyclic acid anhydride monomer is decomposed by heating. Occurs, resulting in a decrease in heat resistance of the thermoplastic resin composition and poor appearance of the resin film. In the present invention, the content of the component having a decarboxylation catalyst function for the cyclic acid anhydride monomer unit contained in the thermoplastic resin composition is within a predetermined range, and the MFR of the thermoplastic resin composition is It was found that when the amount is within the predetermined range, a decarboxylation reaction is suppressed, and a resin film having good heat resistance and appearance can be obtained. In order to obtain a resin film having good heat resistance and appearance, it is not sufficient that the content of the component having a decarboxylation catalyst function with respect to the cyclic acid anhydride monomer unit is within a predetermined range, It is not sufficient that the MFR of the thermoplastic resin composition is within the predetermined range. The reason why a resin film with good heat resistance and appearance can be obtained by controlling the MFR of the thermoplastic resin composition is that it contributes to the thermal history when the resin film is produced using the thermoplastic resin composition. I think there is.

  In another embodiment of the present invention, the thermoplastic resin composition can be provided. Since the said thermoplastic resin composition is excellent in heat resistance, it can be used suitably in order to form a resin film with a favorable external appearance. The resin film can be used particularly as a polarizer protective film, and an image display device including the polarizer protective film can exhibit high visibility due to the good appearance of the resin film.

[Resin film]
As described above, the resin film of the present invention is a film comprising a thermoplastic resin composition containing the polymer (A) and, if necessary, a methacrylic ester polymer (B), rubber elastic particles and other components. The resin film of the present invention is a film containing the polymer (A) and, if necessary, a methacrylic acid ester polymer (B), rubber elastic particles and other components. The resin film of the present invention is produced by, for example, melt extrusion molding as shown in FIG. 1 after blending the polymer (A) and, if necessary, the polymer (B) to obtain a thermoplastic resin composition. be able to. Specifically, it can be produced by melt-kneading the thermoplastic resin composition at the following melting temperature and / or residence time and forming it into a film. Moreover, a resin film can also be produced by a method of forming a thermoplastic resin composition into a film by a solution casting film forming method, a hot press method, or the like. Especially, from the viewpoint of film thickness uniformity of resin film, manufacturing cost and environmental considerations, by melt-kneading the thermoplastic resin composition at the following melting temperature by the melt extrusion molding method, It is preferable to produce a resin film.

The method for producing the resin film of the present invention by the melt extrusion method will be further described below with reference to FIG.
First, the polymer (A) and, if necessary, the polymer (B) and other components described later are added to obtain a thermoplastic resin composition. Next, the obtained thermoplastic resin composition is melt-kneaded by an extruder (1) such as a single-screw or twin-screw extruder at the following melting temperature, and continuously melted from a die (2) such as a T-die. Is extruded into a film. Further, the extruded film-like molten resin (3) is sandwiched between a pair of cooling rolls (first cooling roll (5) and second cooling roll (6)) having a smooth surface in the cooling unit (4). Then, if necessary, the resin film A can be produced in a non-stretched state by winding it around the third cooling roll (7), forming and cooling it. The method of blending the polymer (A), the polymer (B) and other components is not limited, and may be blended by a known method, a super mixer or a Banbury mixer may be used, or uniaxial or biaxial extrusion It may be melt kneaded with a machine, or a combination thereof. Moreover, a 1st cooling roll, a 2nd cooling roll, and a 3rd cooling roll may be comprised with a metal roll or a metal elastic roll, and may be comprised combining a metal roll and a metal elastic roll.

  The melting temperature of each component in the thermoplastic resin composition is preferably 230 ° C. or higher and 280 ° C. or lower, more preferably 235 ° C. or higher and 270 ° C. or lower, and further preferably 240 ° C. or higher and 260 ° C. or lower. When the melting temperature is not more than the above upper limit, the decarboxylation reaction of the cyclic acid anhydride monomer unit can be further suppressed. When the melting temperature is equal to or higher than the lower limit, the thermoplastic resin composition is sufficiently melted, and the appearance of the resin film is further improved.

  The residence time when melt-kneading the thermoplastic resin composition, that is, the residence time until the thermoplastic resin composition passes through the extruder and exits the T die is preferably 60 minutes or less, more preferably 45 minutes or less, Preferably it is 30 minutes or less. When the residence time of the thermoplastic resin composition is not more than the above upper limit value, the decarboxylation reaction of the cyclic acid anhydride monomer unit can be further suppressed. In addition, a polymer filter may be disposed between the extruder and the T die, and in such a case, it is preferable to set the same residence time. Moreover, the lower limit of the residence time when melt-kneading the thermoplastic resin composition is usually 10 minutes or more.

  When the resin film of the present invention further contains rubber elastic particles, the polymer (A), rubber elastic particles and, if necessary, the polymer (B) were blended to obtain a thermoplastic resin composition. Thereafter, a resin film can be produced by forming a film by a melt extrusion molding method in the same manner as described above. Moreover, it can also manufacture by the method of forming into a film by the solution casting film-forming method, the hot press method, etc. A melt extrusion molding method is preferred.

The method for producing the resin film of the present invention by the melt extrusion molding method when the resin film of the present invention further contains rubber elastic particles will be further described below.
The polymer (A), rubber elastic particles, and, if necessary, the polymer (B) and other components described later are mixed to obtain a thermoplastic resin composition, and then the obtained thermoplastic resin composition Is melt-kneaded with a uniaxial or biaxial extruder at the melting temperature, and the molten resin is continuously extruded from the T-die into a film shape. Further, the extruded film-shaped molten resin has a pair of surfaces. It is sandwiched between smooth cooling rolls (the first cooling roll and the second cooling roll), wound around the third cooling roll as necessary, and shaped and cooled, so that it is long in an unstretched state. A resin film can be manufactured. The method of blending the polymer (A), the polymer (B), the rubber elastic particles and other components is not limited, it may be blended by a known method, a super mixer or a Banbury mixer may be used, It may be melt-kneaded with a single-screw or twin-screw extruder, or a combination thereof. Moreover, a 1st cooling roll, a 2nd cooling roll, and a 3rd cooling roll may be comprised with a metal roll or a metal elastic roll, and may be comprised combining a metal roll and a metal elastic roll.

The amount of CO ₂ generated per gram of resin film between 150 ° C. and 300 ° C. of the resin film of the present invention is preferably 0.29 mg or less, more preferably 0.25 mg or less, still more preferably 0.2 mg or less, particularly preferably It is 0.18 mg or less. When the CO ₂ generation amount is not more than the above upper limit value, a resin film with few bubbles can be obtained. The lower limit of the CO ₂ generation amount per 1 g of the resin film between 150 ° C. and 300 ° C. of the resin film of the present invention is, for example, 0.05 mg or more. The amount of CO ₂ generated per 1 g of the resin film between 150 ° C. and 300 ° C. can be measured, for example, by thermogravimetry-mass spectrometry (TG-MS). The measurement can be performed, for example, in a nitrogen atmosphere at a temperature increase rate of 10 ° C./min. Regarding the measurement of CO ₂ generation amount per 1 g of resin film, when calcium oxalate monohydrate was measured by thermogravimetry-mass spectrometry (TG-MS), it was 1 per 1 mole of calcium oxalate monohydrate. Mole of CO ₂ is generated, and the amount of CO ₂ generated per 1 g of the resin film can be determined based on the integrated intensity at this time. CO ₂ generated by the decarboxylation function is present as a bubble defect in the resin film. When a resin film is used as the polarizer protective film, the bubble defect may cause a problem in the image display function at a diameter of 100 μm or more. It is preferable that bubble defects having a diameter of 100 μm or more in the resin film are 0.0 pieces / m ² or less. In addition, the diameter of the bubble can be measured by observing with an optical microscope, for example. Moreover, a bubble defect can be measured, for example, by counting the number of bubble defects in the resin film 5m ² .

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

  In the resin film of the present invention, the light transmittance at a wavelength of 260 nm converted to a film thickness of 40 μm is preferably 2% or less, and the light transmittance at a wavelength of 380 nm converted to a film thickness of 40 μm is preferable. Is 5% or less. When the light transmittance at wavelengths of 260 nm and 380 nm is less than or equal to the above upper limit value, when the resin film of the present invention is used as a polarizer protective film, it is possible to prevent performance degradation of the liquid crystal cell.

  The 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 effects of the present invention are not impaired. When the resin film is a multilayer film, each layer may be formed from a thermoplastic resin composition having the same composition, or may be formed from a thermoplastic resin composition having a different composition. Different types of thermoplastic resin compositions contain different types of resin, the same type of resin but different contents of each resin, the same type and content of resin, In any case, including those having different components.

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

[Polarizer protective film]
The resin film of the present invention is suitable as a polarizer protective film. That is, in another embodiment of the present invention, there is provided a polarizer protective film comprising the resin film of the present invention (hereinafter also referred to as “polarizer protective film of the present invention”). In addition, a polarizer protective film is a film used in order to arrange | position on one or both surfaces of a polarizer, and to protect a polarizer. In addition to the polarizer protective film, the resin film of the present invention includes architectural daylighting members such as windows and carport roof materials, vehicle daylighting members such as car windows, agricultural daylighting members such as greenhouses, lighting members, and front filters. It may be laminated on display members, etc., and as a decorative film, it may be laminated on housings of home appliances, vehicle interior members, interior building materials, wallpaper, decorative boards, entrance doors, window frames, baseboards, etc. Good.

〔Polarizer〕
In another embodiment of the present invention, there is provided a polarizing plate (hereinafter also referred to as “polarizing plate of the present invention”) in which the polarizer protective film is disposed on at least one surface of the polarizer. It is preferable that the polarizer protective film and the polarizer are bonded. A polarizer is an optical film having a function of emitting polarized light with respect to incident light such as natural light. The polarizer has a property of absorbing linearly polarized light having a vibration surface in a certain direction incident on the film surface and transmitting linearly polarized light having a vibration surface perpendicular to the polarizing surface, and in a certain direction incident on the film surface. There are a polarization separator having a property of reflecting linearly polarized light having a vibration surface and transmitting linearly polarized light having a vibration surface orthogonal thereto, and an elliptical polarizer in which a polarizing film and a retardation film are laminated. As a suitable specific example of a polarizer, particularly a linear polarizer (also referred to as a polarizing film), a uniaxially stretched polyvinyl alcohol resin film is adsorbed and oriented with a dichroic dye such as iodine or a dichroic dye. Can be mentioned. The thickness of the polarizer is usually 5 μm to 40 μm.

  When a 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 triacetyl cellulose 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 and the polarizer of the present invention are preferably bonded with an adhesive. Prior to bonding, at least one of the bonding surfaces is preferably 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 was bonded to the polarizer with an adhesive as compared with a polarizer protective film comprising a resin containing a methacrylic acid ester monomer unit and no aromatic vinyl monomer unit. Sometimes it has excellent adhesive strength.

  The adhesive can be arbitrarily selected and used from those that exhibit adhesive strength to each member. Typically, a water-based adhesive, that is, an active energy ray-curable adhesive containing an adhesive component dissolved in water or an adhesive component dispersed in water, or a component that cures upon irradiation with active energy rays is used. Can be mentioned. Among these, an active energy ray-curable adhesive is preferable from the viewpoint of productivity.

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

  In order to improve the adhesiveness, it is preferable to add a curable component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to the water-based adhesive having a polyvinyl alcohol resin as a main component. Examples of water-soluble epoxy resins include polyamide polyamines obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a polycarboxylic acid such as adipic acid and epichlorohydrin. An epoxy resin etc. are mentioned. Commercially available products may be used as the polyamide polyamine epoxy resin, such as “Smiles Resin 650” and “Smiles Resin 675” manufactured by Taoka Chemical Co., Ltd., “WS-525” manufactured by Seiko PMC Co., Ltd. Is mentioned. The addition amount of the curable component or the crosslinking agent is preferably 1 to 100 parts by weight, more preferably 1 to 50 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. When the addition amount is small, the effect of improving the adhesiveness is reduced, while when the addition amount is large, the adhesive layer may become brittle.

  When a urethane resin is used as the main component of the aqueous adhesive, a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group can be given as an example of a suitable adhesive composition. The polyester ionomer type urethane resin here is a urethane resin having a polyester skeleton, into which a small amount of ionic component (hydrophilic component) is introduced. An ionomer type urethane resin is directly emulsified in water without using an emulsifier and becomes an emulsion, so that it is preferable as an aqueous adhesive.

  When an active energy ray-curable adhesive is used, components that cure by irradiation of active energy rays that constitute the active energy ray (hereinafter sometimes simply referred to as “curable components”) include epoxy compounds, oxetane compounds, and acrylic compounds. Etc. When a cationically polymerizable compound such as an epoxy compound or an oxetane compound is used, a cationic polymerization initiator is blended. Further, when a radical polymerizable compound such as an acrylic compound is used, a radical polymerization initiator is blended. Among these, an adhesive having an epoxy compound as one of the curable components is preferable, and an adhesive having an alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated carbocycle as one of the curable components is more preferable. Moreover, you may use an oxetane compound together.

As the epoxy compound, commercially available products may be used. For example, “Epicoat” series manufactured by Mitsubishi Chemical Corporation, “Epicron” series manufactured by DIC Corporation, “Epototo” series manufactured by Nippon Steel & Sumitomo Metal Corporation, ADEKA Corporation “Adeka Resin” series manufactured by Nagase ChemteX Corporation, “Denacol” series manufactured by Nagase ChemteX Corporation, “Dow Epoxy” series manufactured by Dow Chemical Co., “Tepic” manufactured by Nissan Chemical Industries, Ltd., and the like.
As the alicyclic epoxy compound in which the epoxy group is directly bonded to the saturated carbocyclic ring, a commercially available product may be used. For example, “Celoxide” series and “Cyclomer” series manufactured by Daicel Chemical Industries, Ltd., Dow -The “Syracure” series manufactured by Chemical Company, etc.
As the oxetane compound, commercially available products may be used, and examples thereof include “Aron Oxetane” series manufactured by Toagosei Co., Ltd., “ETERRNACOLL” series manufactured by Ube Industries, Ltd., and the like.

  As the cationic polymerization initiator, commercially available products may be used. For example, “Kayacure” series manufactured by Nippon Kayaku Co., Ltd., “Syracure” series manufactured by Dow Chemical Co., Ltd., photoacid generator manufactured by San Apro Co., Ltd. “CPI” series, photo acid generators “TAZ”, “BBI” and “DTS” manufactured by Midori Chemical Co., Ltd., “Adekaoptomer” series manufactured by ADEKA Co., Ltd., “RHODORSIL” manufactured by Rhodia Series.

  The active energy ray-curable adhesive can contain a photosensitizer as necessary. By using a photosensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the cured product layer can be further improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, anthracene compounds, halogen compounds, and photoreducible dyes.

  Various additives can be blended with the active energy ray-curable adhesive within a range that does not impair the adhesiveness. 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 an antifoaming agent. Furthermore, a curable component that cures by a reaction mechanism different from cationic polymerization can be blended within a range that does not impair the adhesion.

  The active energy ray-curable adhesive may have the same composition or a different composition, but it is preferable that irradiation of active energy rays for curing both is performed simultaneously.

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

  An active energy ray-curable adhesive is applied to the polarizer or the polarizer protective film of the present invention to form a coating film, and the polarizer and the polarizer protective film of the present invention are overlapped through the formed coating film. By irradiating with active energy rays, the active energy ray-curable resin is cured, and the polarizer and the polarizer protective film of the present invention are adhered to each other, whereby the polarizing plate of the present invention can be obtained.

  The thickness of the adhesive layer obtained using the active energy ray-curable adhesive is preferably 1 μm to 50 μm, and more preferably 1 μm to 10 μm. The thickness of an adhesive bond layer can be adjusted with the thickness of the coating film formed in a polarizer or the polarizer protective film of this invention.

  The polarizing plate of the present invention can be used in an image display device in combination with a display element such as a liquid crystal cell or an organic EL element. For example, it can be attached to a liquid crystal cell to form a liquid crystal panel used in a liquid crystal display device. It is preferable that the polarizing plate and the liquid crystal cell are bonded via an adhesive layer using an adhesive. This pressure-sensitive adhesive layer is generally formed of an acrylic pressure-sensitive adhesive having an acrylic resin mainly composed of an acrylate ester and an acrylic resin copolymerized with a functional group-containing acrylic monomer. A liquid crystal panel in which a polarizing plate is bonded to a liquid crystal cell via an adhesive layer can be used for a liquid crystal display device.

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

The extrusion apparatus used in Examples and Comparative Examples is the apparatus shown in FIG. 1, and the configuration thereof is as follows.
Extruder: Screw diameter 65mm, single screw, vented extruder (manufactured by Toshiba Machine Co., Ltd.)
・ T-die: Multi-manifold die with a width of 800 mm and a lip interval of 1 mm (manufactured by Hitachi Zosen)
-1st cooling roll: Metal elastic roll-2nd cooling roll: Metal roll-3rd cooling roll: Metal roll

  The metal elastic roll has a 2 mm thick stainless steel thin film with one side mirrored so as to cover the outer periphery of the shaft roll made of stainless steel so that the mirror finished surface is the outer surface of the roll. It is a metal elastic roll having an outer diameter of 250 mm, in which a fluid made of heat transfer oil is sealed between the metal thin film. The metal roll is a spiral roll made of stainless steel having a mirror-finished surface and having an outer diameter of 250 mm.

[Thermoplastic resin composition]
The monomer unit composition and general physical properties of the polymers (A) (Polymers A-1 and A-2) used in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1. Table 2 shows the composition and general physical properties of the union (B) (polymers B-1 and B-2). The weight average molecular weight Mw and number average molecular weight Mn of each resin were determined by gel permeation chromatography (GPC) measurement (in terms of polymethyl methacrylate).

  The rubber elastic particles used in Examples 1 to 3 and Comparative Examples 1 to 3 were all core-shell type butadiene rubber. Table 3 shows the characteristics of the rubber elastic particles (rubbers 1 to 3).

  Each polymer A, polymer B, and rubber were introduced into an extruder at a weight percent shown in Table 4 and melt-kneaded to obtain a thermoplastic resin composition.

[Production of resin film]
The extruder, the T die, and the first to third cooling rolls were arranged as shown in FIG. Subsequently, the obtained thermoplastic resin composition was melt-kneaded at 245 ° C. with an extruder, and each was supplied to a T die having a set temperature of 245 ° C. The film-like molten resin extruded from the T-die is sandwiched between the first cooling roll and the second cooling roll arranged opposite to each other, wound around the third cooling roll, and molded and cooled to obtain a resin film having a thickness of 60 μm. It was. The residence time from exiting the extruder to the T-die was 30 minutes. In addition, the surface temperature of the 1st cooling roll was 80 degreeC, the surface temperature of the 2nd cooling roll was 80 degreeC, and the surface temperature of the 3rd cooling roll was 100 degreeC. These temperatures are values obtained by actually measuring the surface temperature of each cooling roll.

  The MFR (measurement temperature 230 ° C., load 37.3 N) of each thermoplastic resin composition was measured according to JIS K7210. Further, the metal element concentration of each thermoplastic resin composition was measured by ashing / acid dissolution / ICE AES method. The results obtained are shown in Table 5.

  The presence or absence of bubble defects was evaluated by observing, with an optical microscope, the places where light scattering was observed when the obtained resin films were tilted at 45 ° under a fluorescent lamp. The observation magnification of the optical microscope was 500 times. The observed bubble diameter was about 100 μm.

In order to evaluate the amount of CO ₂ produced resin film, the following measurement conditions, it was TG-MS measurement using a resin film, respectively.
<TG-MS>
Measurement was performed using a thermogravimetric mass spectrometry simultaneous measurement apparatus TG-DTA2020SA / MS9610 (Bruker AXS), and the measurement conditions were as follows.
(TG-DTA)
Bread: Al (open type)
Measurement range: room temperature (23 ° C.) to 300 ° C.
Temperature increase rate: 10 ° C / min
Atmosphere: N ₂ 200 mL / min
(MS)
Ionization: EI
Scanning range: m / z = 1 to 100 (CO ₂ = 44)

The amount of CO ₂ generated is the same as the above measurement conditions except that the measurement range for calcium oxalate monohydrate is 23 ° C. (room temperature) to 1000 ° C. and the temperature increase rate is 20 ° C./min. TG-MS measurement was performed and the amount of CO ₂ generated between 600 ° C. and 800 ° C. was used as a reference.

The amount of CO ₂ generated per 1 g of the resin film between 150 ° C. and 300 ° C. calculated from the measurement data was 0.16 mg in Example 1, 0.49 mg in Comparative Example 1, and 0.32 mg in Comparative Example 2. In Example 3, it was 0.17 mg, and in Comparative example 3, it was 0.42 mg.

  Since the appearance of the resin film of the present invention is good, it can be suitably used as a polarizer protective film.

DESCRIPTION OF SYMBOLS 1 Extruder 2 Die 3 Film-like molten resin 4 Cooling unit 5 1st cooling roll 6 2nd cooling roll 7 3rd cooling roll A Resin film

Claims (13)

A resin film comprising a thermoplastic resin composition containing a polymer (A) containing a cyclic acid anhydride monomer unit,
The melt mass flow rate of the thermoplastic resin composition is 2.5 g / 10 min or more,
Resin film containing an alkali metal element as a component having a decarboxylation catalyst function for the cyclic acid anhydride monomer unit, wherein the content of the alkali metal element in the thermoplastic resin composition is 1 ppm or more and 18 ppm or less. . A resin film comprising a thermoplastic resin composition containing a polymer (A) containing a cyclic acid anhydride monomer unit,
The melt mass flow rate of the thermoplastic resin composition is 3.38 g / 10 min or more,
An alkaline earth metal element is contained as a component having a decarboxylation catalyst function for the cyclic acid anhydride monomer unit, and the content of the alkaline earth metal element in the thermoplastic resin composition is 1 ppm or more and 500 ppm or less. There is a resin film.   The resin film of Claim 1 or 2 whose content of the said cyclic acid anhydride monomer unit in the said thermoplastic resin composition is 3 weight% or more on the basis of the said thermoplastic resin composition. 2 200 mL / min under nitrogen atmosphere, thermogravimetric performing Atsushi Nobori rate of 10 ° C. / min - and integrated intensity of the CO ₂ generated from the resin film between the measured Ru 0.99 ° C. to 300 ° C. to by mass spectroscopy, the measurement separately performed from the thermogravimetric measurement except that the heating rate and 20 ° C. / min - mass spectrometry by thermal gravimetric calcium oxalate monohydrate performed under the same conditions as the measurement conditions - mass spectrometry Contrast with the integrated intensity of CO ₂ generated from 1 mol of calcium oxalate monohydrate between 600 ° C. and 800 ° C. measured by
From the CO ₂ generation amount converted from the integrated intensity of CO ₂ generated from 1 mol of calcium oxalate monohydrate measured by thermogravimetry-mass spectrometry, it is calculated based on the ratio of the integrated intensity .
CO ₂ emissions per resin film 1g is below 0.29 mg, the resin film according to claim 1.   The said thermoplastic resin composition is a resin film in any one of Claims 1-4 which further contains the methacrylic acid ester polymer (B) whose melt mass flow rate is 3 g / 10min or more.   The resin film according to any one of claims 1 to 5, wherein the thermoplastic resin composition further contains 5% by weight or more and 40% by weight or less of rubber elastic body particles.   The resin film according to claim 6, wherein a 1% weight reduction temperature of the rubber elastic particles is 305 ° C. or higher.   The method for producing a resin film according to claim 1, wherein the thermoplastic resin composition is melt-kneaded at a melting temperature of 230 ° C. or higher and 280 ° C. or lower and formed into a film shape.   The method for producing a resin film according to any one of claims 1 to 7, wherein the thermoplastic resin composition is melt-kneaded for a residence time of 60 minutes or less and formed into a film shape.   A polarizer protective film comprising the resin film according to claim 1.   The polarizing plate by which the polarizer protective film of Claim 10 is arrange | positioned on the at least one surface of the polarizer. A thermoplastic resin composition containing a polymer (A) containing a cyclic acid anhydride monomer unit,
The melt mass flow rate of the thermoplastic resin composition is 2.5 g / 10 min or more,
Thermoplastic containing an alkali metal element as a component having a decarboxylation catalyst function for the cyclic acid anhydride monomer unit, and a content of the alkali metal element in the thermoplastic resin composition of 1 ppm or more and 18 ppm or less. Resin composition. A thermoplastic resin composition containing a polymer (A) containing a cyclic acid anhydride monomer unit,
The melt mass flow rate of the thermoplastic resin composition is 3.38 g / 10 min or more,
An alkaline earth metal element is contained as a component having a decarboxylation catalyst function for the cyclic acid anhydride monomer unit, and the content of the alkaline earth metal element in the thermoplastic resin composition is 1 ppm or more and 500 ppm or less. A thermoplastic resin composition.

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