JP2018109087A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition that resists coloration when melted and mixed at high temperature.SOLUTION: A thermoplastic resin composition contains a copolymer (A) containing an aromatic vinyl monomer unit and a cyclic acid anhydride monomer unit. In the thermoplastic resin composition, a logarithm lnk of a reaction rate constant k(s) at 300°C is 0.05 or less.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic resin composition. The present invention also provides a resin film composed of the thermoplastic resin composition and a method for producing the same, a polarizer protective film composed of the resin film, a polarizing plate on which the film is laminated, and a release film composed of the resin film The present invention also relates to a polarizer with a release film laminated.

  As an optical film that constitutes an image display device such as a liquid crystal display device, a polarizer protective film that is laminated and bonded to one or both sides of a polarizer is widely used in order to protect the polarizer. In addition, in order to temporarily protect a polarizer before being incorporated in a polarizing plate or the like, a release film that can be peelably laminated on one or both sides of the polarizer is also widely known. Such a polarizer protective film or a release film may be composed of an acrylic resin composition as a material. For example, Patent Document 1 discloses an optical film containing an acrylic resin.

Special table 2012-504783 gazette

  The optical film as disclosed in Patent Document 1 is usually produced by melt-kneading a resin composition and forming it into a film shape. At this time, the processability of the resin composition is improved by raising the heating temperature at the time of melting, but the molded film is likely to be colored by undergoing melt-kneading at a high temperature. In addition to the appearance defects, such coloring may cause defects in optical properties in the polarizer protective film that is a part of the constituent members of the image display device and the optical laminate.

  Accordingly, an object of the present invention is to provide a thermoplastic resin composition that is difficult to be colored when melt-kneaded at a high temperature. Another object of the present invention is to provide a resin film composed of the thermoplastic resin composition (particularly, a polarizer protective film, a release film for protecting a polarizer, etc.), and a polarizing plate or a polarizer obtained by laminating them. .

The present invention provides the following preferred embodiments.
[1] A thermoplastic resin composition comprising a copolymer (A) containing an aromatic vinyl monomer unit and a cyclic acid anhydride monomer unit, the thermoplastic resin composition at 300 ° C. A thermoplastic resin composition having a logarithm of a reaction rate constant k (s ⁻¹ ) of 0.05 or less.
[2] A polymer containing an acrylic monomer unit, the polymer comprising a polymer (B) substantially free of an aromatic vinyl monomer unit and a cyclic acid anhydride monomer unit, The thermoplastic resin composition according to [1].
[3] The thermoplastic resin according to [1] or [2], comprising 0 to 30% by mass of rubber elastic particles having an average particle diameter of 10 nm to 350 nm based on the total mass of the thermoplastic resin composition. Composition.
[4] A method for producing a resin film, comprising melt-kneading the thermoplastic resin composition according to any one of [1] to [3] above at a melting temperature of 230 ° C. or higher and 280 ° C. or lower and forming into a film shape. .
[5] A method for producing a resin film, comprising melt-kneading the thermoplastic resin composition according to any one of [1] to [3] above for a residence time of 20 minutes or more and forming the film.
[6] A resin film composed of the thermoplastic resin composition according to any one of [1] to [3].
[7] A polarizer protective film comprising the resin film according to [6].
[8] A polarizing plate in which the polarizer protective film according to [6] is laminated on at least one surface of a polarizer via an adhesive layer or an adhesive layer.
[9] A polarizer with a release film, in which a release film composed of the resin film according to [6] is laminated on at least one surface of the polarizer.

  According to the present invention, it is possible to provide a thermoplastic resin composition that is difficult to be colored when melt-kneaded at a high temperature. Moreover, the resin film which consists of such a thermoplastic resin composition, and the polarizing plate or polarizer which laminated | stacked this can also be provided.

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

  Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention.

[Thermoplastic resin composition]
The thermoplastic resin composition of the present invention comprises a copolymer (A) containing an aromatic vinyl monomer unit and a cyclic acid anhydride monomer unit.

（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。 <Copolymer (A)>
In the present invention, the aromatic vinyl monomer unit constituting the copolymer (A) 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. Aromatic vinyl monomers readily copolymerize with cyclic acid anhydride monomers.
Specific examples of the aromatic vinyl monomer unit include the following formula (1):

(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.

  As a halogen atom in Formula (1), a fluorine atom, a chlorine atom, and a bromine atom are mentioned, for example. Examples of the alkyl group having 1 to 12 carbon atoms include straight chain 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 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.

  Specific examples of the aromatic vinyl monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, and 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-chloro Styrene, 3-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene Down, 2-bromostyrene, 3-bromostyrene, 4-bromostyrene, 2,4-dibromostyrene, alpha-bromostyrene, beta-bromostyrene, 2-hydroxystyrene and 4-hydroxy styrene. Of these, styrene and α-methylstyrene are preferable. Two or more aromatic vinyl monomers may be used in combination.

  The content of the aromatic vinyl monomer unit in the copolymer (A) is preferably 50% by mass or more with respect to 100% by mass of all the monomer units constituting the copolymer (A). When the thermoplastic resin composition of the present invention contains an aromatic vinyl monomer unit in an amount equal to or more than the above lower limit, the fluidity at the time of melting is improved, and the film can be easily formed into a film shape. Content of the aromatic vinyl monomer unit in a polymer (A) becomes like this. Preferably it is 50-80 mass%, More preferably, it is 52-78 mass%, More preferably, it is 55-75 mass%.

（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し、ｎは０または１の整数を表す）
で表される環状酸無水物単量体単位が挙げられる。 In the present invention, the cyclic acid anhydride monomer unit constituting the copolymer (A) is derived from the cyclic acid anhydride monomer. Specific examples of the cyclic acid anhydride monomer unit include the following formula (2):

(Wherein 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, and n represents an integer of 0 or 1)
The cyclic acid anhydride monomer unit represented by these is mentioned.

  As a halogen atom and a C1-C12 alkyl group, the thing similar to what was illustrated in the aromatic vinyl monomer unit represented by the said Formula (2) is mentioned.

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, glutaric anhydride, citraconic anhydride, dimethyl maleic anhydride, dichloromaleic anhydride, bromomaleic anhydride, dibromomaleic anhydride, phenylmaleic anhydride and diphenylanhydride. Maleic acid is mentioned, and 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 copolymer (A) is the same as that of the copolymer (A) in terms of transparency and heat resistance of the thermoplastic resin composition and dimensional stability in a high temperature environment. Preferably it is 5-35 mass% with respect to 100 mass% of all the monomer units to comprise, More preferably, it is 10-30 mass%, More preferably, it is 15-25 mass%.

  The copolymer (A) contained in the thermoplastic resin composition of the present invention preferably contains an acrylic monomer unit in addition to the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit. . When the copolymer (A) contains an acrylic monomer unit, the toughness of the resulting resin film can be improved.

In the present invention, the acrylic monomer unit that can constitute the copolymer (A) is a monomer unit derived from methacrylic acid, acrylic acid, a methacrylic acid ester monomer, or an acrylic 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 and transparency point of a thermoplastic resin composition.
Examples of the acrylate monomer include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, Examples thereof include alkyl or cycloalkyl ester monomers having 1 to 8 carbon atoms of acrylic acid such as cyclohexyl acrylate. Two or more acrylate monomers may be used in combination. Among these, an alkyl ester monomer having 1 to 7 carbon atoms of acrylic acid is preferable, and methyl acrylate is more preferable in terms of heat resistance and transparency of the thermoplastic resin composition.

  The content of the acrylic monomer unit in the copolymer (A) is 100% by mass of all the monomer units constituting the copolymer (A) in terms of transparency of the thermoplastic resin composition. The content is preferably 5 to 40% by mass, more preferably 5 to 35% by mass, further preferably 5 to 30% by mass, and particularly preferably 5 to 25% by mass.

  In the present invention, the copolymer (A) is a monomer unit, that is, an aromatic vinyl monomer unit, a cyclic acid anhydride monomer unit, and an acrylic unit, as long as the effects of the present invention are not impaired. A monomer unit other than the monomer unit may be contained. Monomer units other than the monomer units described above are monomers that can be copolymerized with at least one monomer constituting the copolymer (A) among the monomers that lead to the monomer units described above. The monomer unit derived from the monomer may be used, and preferably, the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit constituting the copolymer (A), and, if included, acrylic It is a monomer unit derived from a monomer that can be copolymerized with all of the monomers leading to the system monomer unit. When the monomer unit other than the above-described monomer units is included, the content thereof is preferably 50% by mass or less with respect to 100% by mass of all the monomer units constituting the copolymer (A). Yes, more preferably 30% by mass or less, still more preferably 10% by mass or less. The lower limit of the content of monomer units other than the monomer units described above is, for example, 0% by mass or more.

  The weight average molecular weight (Mw) of the copolymer (A) is from the viewpoint of handling properties when molding a resin film from the thermoplastic resin composition of the present invention or handling properties of the film during stretching of the resin film of the present invention. , Preferably it is 90000-300000, More preferably, it is 100,000-250,000, More preferably, it is 110000-230,000.

  The number average molecular weight (Mn) of the copolymer (A) is from the viewpoint of handling properties when molding a resin film from the thermoplastic resin composition of the present invention or film handling properties when the resin film of the present invention is stretched. , Preferably 35000 to 100,000, more preferably 40000 to 90000, and even more preferably 45000 to 85000. In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the copolymer (A) can be measured in terms of polymethyl methacrylate by gel permeation chromatography (GPC) measurement, for example.

  The molecular weight distribution (Mw / Mn) of the copolymer (A) is preferably 1.3 to 4, more preferably 1.5 to, from the viewpoint of moldability from the thermoplastic resin composition of the present invention to a resin film. 3.5, more preferably 1.7-3.

  The melt mass flow rate (MFR) of the copolymer (A) is 0.4 g / 10 min or more, preferably 0.5 g / 10 min or more, more preferably 0.6 g / 10 min or more, preferably 10 g / It is 10 minutes or less, More preferably, it is 8 g / 10 minutes or less, More preferably, it is 7 g / 10 minutes or less. When the MFR of the copolymer (A) is not less than the above lower limit value, when the resin film is produced from the thermoplastic resin composition by melt extrusion, the removal due to the cyclic acid anhydride monomer unit during melt kneading is performed. Carbonic acid reaction can be suppressed. Moreover, when MFR of a copolymer (A) is below the said upper limit, when manufacturing a resin film by melt extrusion molding, stability of the discharge amount of the fuse | melted thermoplastic resin composition is favorable. In the present invention, the MFR of the polymer can be measured according to JIS K7210 under the conditions of a measurement temperature of 230 ° C. and a load of 37.3N.

  The copolymer (A) is obtained by polymerizing each monomer constituting the copolymer 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. Can be manufactured. By changing the amount of each monomer used, the content of each monomer unit in the copolymer (A) can be controlled.

  Content of the copolymer (A) in the thermoplastic resin composition of this invention is 10-100 mass% normally with respect to the total mass of a thermoplastic resin composition, Preferably it is 10-80 mass%. Yes, more preferably 15 to 65% by mass, still more preferably 20 to 50% by mass. When the content of the copolymer (A) in the thermoplastic resin composition is within the above range, the heat resistance can be further improved, and a resin film with better appearance can be obtained.

<Polymer (B)>
The thermoplastic resin composition of the present invention includes, for example, an acrylic monomer unit in addition to the copolymer (A) in order to adjust the melt mass flow rate of the thermoplastic resin composition. You may contain the polymer (B) which does not contain a monomer unit and a cyclic acid anhydride monomer unit substantially. By including the polymer (B) in addition to the copolymer (A), it is easy to adjust the logarithm 1nk of the reaction rate constant k (s ⁻¹ ) of the thermoplastic resin composition. Moreover, moderate toughness can be provided to the thermoplastic resin composition.

  The acrylic monomer unit constituting the polymer (B) is a monomer unit derived from methacrylic acid, acrylic acid, a methacrylic acid ester monomer, or an acrylic acid ester monomer. Examples of the monomer or the acrylate monomer include those similar to those exemplified above for the copolymer (A). Of these, methyl methacrylate and methyl acrylate are preferred. Two or more methacrylic acid ester monomers and / or acrylic acid ester monomers may be used. In particular, when the polymer (B) contains a monomer unit derived from two or more kinds of acrylic monomers, high transparency and heat decomposability can be secured, and at the same time, the melt mass flow rate Adjustment is easy.

  When the acrylic monomer unit in the copolymer (A) and the acrylic monomer unit in the polymer (B) are the same, the compatibility of the resin composition and the transparency of the resulting resin film It is preferable that it tends to be excellent.

  The content of the acrylic monomer unit in the polymer (B) is usually 50% by mass or more, preferably 70% by mass with respect to 100% by mass of all the monomer units constituting the polymer (B). % Or more, more preferably 90% by mass or more, and still more preferably 92% by mass or more.

  The polymer (B) is substantially free of aromatic vinyl monomer units and cyclic acid anhydride monomer units. Here, in the present specification, “substantially free” means an aromatic vinyl monomer unit and a cyclic acid anhydride with respect to 100% by mass of all the monomer units constituting the polymer (B). It means that the monomer units are each 5% by mass or less, and in one preferred embodiment of the present invention, the aromatic vinyl monomer unit and the cyclic acid anhydride monomer contained in the polymer (B) Each body unit is 0 mass%.

  As long as the effect of the present invention is not impaired, the polymer (B) is in addition to the above-mentioned acrylic monomer units, other monomer units that are not aromatic vinyl monomer units and cyclic acid anhydride monomer units. It may contain body units. Examples of such other monomers include unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile; cyclic imide monomers such as phenylmaleimide and cyclohexylmaleimide.

  The weight average molecular weight (Mw) of the polymer (B) is preferably 40000 to 200000, more preferably 50000 to 150,000, and further preferably 60000 to 120,000, from the viewpoint of increasing MFR.

  The number average molecular weight (Mn) of the polymer (B) is preferably 20000 to 100,000, more preferably 30000 to 70000, and further preferably 35000 to 60000, from the viewpoint of increasing the MFR. In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer (B) can be measured, for example, in terms of polymethyl methacrylate by gel permeation chromatography (GPC) measurement.

  The molecular weight distribution (Mw / Mn) of the polymer (B) is preferably 1.3 to 4, more preferably 1.5 to 3 from the viewpoint of moldability from the thermoplastic resin composition of the present invention to a resin film. .5, more preferably 1.7-3.

  MFR of a polymer (B) becomes like this. Preferably it is 1.5 g / 10min or more, More preferably, it is 2.0 g / 10min or more, More preferably, it is 2.5 g / 10min or more. When the MFR of the polymer (B) is not less than the above lower limit, the MFR of the thermoplastic resin composition can be easily controlled. In addition, the upper limit of MFR of a polymer (B) is 40 g / 10min or less normally from a viewpoint of moldability.

  The polymer (B) is composed of a methacrylic acid ester monomer and / or an acrylic acid ester monomer, and other monomers as necessary, a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension weight, It can manufacture by making it superpose | polymerize by well-known methods, such as a combined method and a casting polymerization method.

  The content of the polymer (B) in the thermoplastic resin composition is preferably 20% by mass or more, more preferably 30% by mass or more, with respect to the total mass of the thermoplastic resin composition. Preferably it is 80 mass% or less, More preferably, it is 70 mass% or less. Control of MFR of a thermoplastic resin composition becomes easy that content of a polymer (B) is more than the said lower limit. When the content of the polymer (B) is not more than the above upper limit, the heat resistance of the thermoplastic resin composition can be further improved, and a resin film having a good appearance can be obtained.

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

  The particle diameter of the rubber elastic particles is, for example, 10 nm or more, preferably 50 nm or more, more preferably 100 nm or more, and for example, 350 nm or less, preferably 320 nm 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. Moreover, the internal haze of a thermoplastic resin composition is hard to become high that the particle diameter of a rubber elastic body particle is below the said upper limit. The particle diameter of the rubber elastic particles can be measured as a number average particle diameter by observation with an electron microscope, and can be calculated as an average value of 100 rubber elastic particles, for example.

  The content of the elastic rubber particles in the thermoplastic resin composition may be 0 (zero)% by mass with respect to the total mass of the thermoplastic resin composition, but is preferably 5 to 30% by mass, preferably 7 to 28%. It is 10 mass%, More preferably, it is 10-25 mass%. 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 rubber elastic body particles in the thermoplastic resin composition is not more than the above upper limit, the heat resistance of the thermoplastic resin composition 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.

  In the present invention, the 1% weight loss temperature refers to a rubber elastic body when the rubber elastic body particles are previously dried at 80 ° C. for 12 hours or more and then heated at a rate of 10 ° C./min in a nitrogen atmosphere. It means the temperature when the weight loss of the particles becomes 1% of the total weight. The 1% weight loss temperature can be measured by differential thermal and thermogravimetric analysis (TG-DTA).

  The rubber elastic particles may contain a metal element in the process of producing the rubber elastic particles. As will be described later, since this metal element can contribute to the decomposition reaction of the copolymer (A), the stability of the thermoplastic resin composition tends to be lowered, so that the metal element contained in the rubber elastic particles The amount is preferably as small as possible. 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.

  The thermoplastic resin composition of the present invention may contain components other than the copolymer (A), the polymer (B) and the rubber elastic particles. Other components include, for example, light diffusing agents, matting agents, dyes, light stabilizers, ultraviolet absorbers, antioxidants, mold release agents, flame retardants, antistatic agents, lubricants, and other resins Resins other than the union (A) and the polymer (B)] and the like.

  The thermoplastic resin composition of the present invention can be produced by a conventionally known method. Specifically, for example, the copolymer (A) and, if necessary, the polymer (B), rubber elastic particles, Other components can be produced by a method of melt-kneading using an extruder. The form of the thermoplastic resin composition of the present invention is not particularly limited, but is preferably a pellet from the viewpoint of easy handling.

In the present invention, the logarithm lnk of the reaction rate constant k (s ⁻¹ ) at 300 ° C. of the thermoplastic resin composition is 0.05 or less. The logarithm lnk of the reaction rate constant k (s ⁻¹ ) is an index indicating the stability of the thermoplastic resin composition. If this value exceeds 0.05, the stability of the thermoplastic resin composition becomes low and the heat resistance becomes low. Since it is inferior in decomposability, when such a thermoplastic resin composition is melt-kneaded in a high temperature environment to form a resin film, the resulting resin film tends to be colored. A colored resin film becomes a resin film having defects in appearance and optical properties. The logarithm 1nk of the reaction rate constant k (s ⁻¹ ) of the thermoplastic resin composition of the present invention is preferably 0.049 or less, more preferably 0.048 or less, and even more preferably 0.047 or less. is there. Moreover, the lower limit value of the logarithm lnk of the reaction rate constant k (s ⁻¹ ) is, for example, 0.001 or more.
In addition, the logarithm 1nk of the reaction rate constant k (s < ^-1 >) in 300 degreeC of a thermoplastic resin composition can be measured and calculated according to the method described in the Example mentioned later.

The logarithmic value lnk of the reaction rate constant k (s ⁻¹ ) of the thermoplastic resin composition is, for example, the ratio of the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit contained in the thermoplastic resin composition. It is possible to control by adjusting. As a method of adjusting the ratio of the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit contained in the thermoplastic resin composition, the contents of the copolymer (A) and the polymer (B), the copolymer The method of adjusting content etc. of the acryl-type monomer unit contained in a polymer (A) is mentioned. Specifically, for example, increasing the content of the polymer (B) contained in the thermoplastic resin composition or increasing the proportion of acrylic monomer units contained in the copolymer (A). Thus, the value of the logarithm lnk can be reduced. In particular, by forming the thermoplastic resin composition of the present invention from at least two types of polymers [that is, a copolymer (A) and a polymer (B)], a copolymer having a predetermined composition / configuration ( A ratio of the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit contained in the thermoplastic resin composition is easily controlled by adjusting the blending amount of the polymer (B) with respect to A). This makes it possible to easily control the logarithmic value lnk of the reaction rate constant k (s ⁻¹ ) of the thermoplastic resin composition. By using the polymer (B) as a diluent, various thermoplastic resin compositions can be easily obtained using the same copolymer (A), which is advantageous from the productivity and industrial viewpoints. It is.

  For example, in one preferred embodiment of the present invention, the content of the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit in the thermoplastic resin composition is a total based on the thermoplastic resin composition, Preferably it is 15-35 mass%, More preferably, it is 20-30 mass%. When the content of the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit in the thermoplastic resin composition is 35% by mass or less based on the thermoplastic resin composition, it is more difficult to be colored, It is preferable from the point of heat resistance that it is 15 mass% or more.

  Moreover, it is preferable that content of the aromatic vinyl monomer unit in a thermoplastic resin composition is 5-30 mass% on the basis of the total mass of a thermoplastic resin composition, and is 7-25 mass%. It is more preferable that the content is 10 to 25% by mass. Furthermore, the content of the cyclic acid anhydride monomer unit in the thermoplastic resin composition is preferably 3 to 30% by mass based on the total mass of the thermoplastic resin composition, and is 4 to 25% by mass. More preferably, it is more preferably 5 to 20% by mass. When the content of the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit in the thermoplastic resin composition is within the above ranges, the stability of the thermoplastic resin composition is improved and the thermal decomposition resistance is also improved. For example, even when the thermoplastic resin composition is melt-kneaded under a high temperature condition exceeding 230 ° C., for example, coloring of the resin film obtained by molding can be suppressed, and appearance and optical characteristics An excellent resin film can be obtained.

In addition, in order to obtain the thermoplastic resin composition of the present invention that can form a resin film having high stability and heat decomposability and excellent in appearance and optical properties without coloring, in the thermoplastic resin composition In addition to controlling the content of the aromatic vinyl monomer unit and the cyclic acid anhydride monomer unit, it is also useful to keep the content of the metal element contained in the thermoplastic resin composition as low as possible. . That is, by reducing the content of the metal element in the thermoplastic resin composition, the logarithmic value lnk of the reaction rate constant k (s ⁻¹ ) of the thermoplastic resin composition can be lowered.

Examples of metal elements include alkali metal elements and alkaline earth metal elements.
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 less than or equal to the above upper limit value, the resulting thermoplastic resin composition is excellent in heat resistance. Can be obtained. In addition, the density | concentration of the alkali metal element contained in a thermoplastic resin composition is 0 (zero) ppm ideally, and is 1 ppm or more normally.

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, a resin film excellent in appearance and optical properties without coloring can be obtained. In addition, the density | concentration of the alkaline-earth metal element contained in a thermoplastic resin composition is ideally 0 (zero) ppm, and is 1 ppm or more normally.
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).

  Since the thermoplastic resin composition of the present invention has high stability and excellent thermal decomposition resistance, it can be suitably used as a material for a resin film such as an optical film. In particular, the resin film composed of the thermoplastic resin composition of the present invention has a good appearance without coloration, and exhibits high visibility when used as a polarizer protective film. Can do. Moreover, it can be used as a release film, and a polarizer with a release film in which the resin film of the present invention is laminated on one side or both sides of a polarizer so that the hue, transmittance, etc. of the polarizer can be easily inspected. .

[Resin film]
The resin film of this invention is a film comprised from the thermoplastic resin composition of this invention. The resin film of the present invention is obtained by mixing the copolymer (A) and, if necessary, the polymer (B) and rubber elastic particles to obtain a thermoplastic resin composition, and then, for example, melting as shown in FIG. It can be produced by an extrusion method. 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.

Hereinafter, the method for producing the resin film of the present invention by the melt extrusion method will be further described with reference to FIG.
First, the copolymer (A) and, if necessary, the polymer (B), rubber elastic particles and other components 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 mixing the copolymer (A), the polymer (B), the rubber elastic particles and other components is not particularly limited, and may be mixed by a known method, and a super mixer or a Banbury mixer may be used. Then, 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 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. In the present invention, even when the melting temperature is within the above range, the thermoplastic resin composition is sufficiently melted, and a resin film having a good appearance without coloring can be obtained while ensuring good processability.

  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 from the T die is preferably 20 minutes or more, more preferably 25 minutes or more. More preferably, it is 30 minutes or more, preferably 60 minutes or less, more preferably 45 minutes or less. In the present invention, even if the residence time of the thermoplastic resin composition is within the above range, the thermoplastic resin composition is sufficiently melted and the resin film has a good appearance without coloring while ensuring good processability. Can be obtained. 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.

  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 laminate | stack on one or both surfaces of a polarizer, and to protect a polarizer.

〔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 via an adhesive layer or an adhesive layer.

  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 of the present invention and the polarizer are preferably bonded via an adhesive layer or an adhesive layer. 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 an acrylate monomer unit and no aromatic vinyl monomer unit. Sometimes it has excellent adhesive strength.

  As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, a conventionally known pressure-sensitive adhesive can be used without particular limitation, and for example, a pressure-sensitive adhesive having a base polymer such as acrylic, rubber-based, urethane-based, silicone-based, or polyvinyl ether-based. Can be used. Moreover, an active energy ray hardening-type adhesive, a thermosetting type adhesive, etc. may be sufficient. Among these, an adhesive having an acrylic resin having excellent transparency, adhesive strength, reworkability, weather resistance, heat resistance and the like as a base polymer is preferable.

  The acrylic pressure-sensitive adhesive is not particularly limited, but (meth) such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. Acrylic acid ester base polymers and copolymer base polymers containing two or more of these (meth) acrylic acid esters are preferably used. Furthermore, polar monomers are copolymerized in these base polymers. Examples of polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, and 2-N, N-dimethylaminoethyl (meth). Mention may be made of monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as acrylate and glycidyl (meth) acrylate.

  These acrylic pressure-sensitive adhesives can be used alone, but are usually used in combination with a crosslinking agent. As the crosslinking agent, a divalent or polyvalent metal ion that forms a carboxylic acid metal salt with a carboxyl group, a polyamine compound that forms an amide bond with a carboxyl group, Examples thereof include polyepoxy compounds and polyol compounds that form an ester bond with a carboxyl group, and polyisocyanate compounds that form an amide bond with a carboxyl group. Among these, polyisocyanate compounds are widely used.

  The active energy ray-curable pressure-sensitive adhesive has the property of being cured by irradiation with active energy rays such as ultraviolet rays and electron beams. It is a pressure-sensitive adhesive that has the property of adhering to an adherend and curing by irradiation with active energy rays to adjust the adhesion. As the active energy ray-curable adhesive, it is particularly preferable to use an ultraviolet curable adhesive. The active energy ray-curable pressure-sensitive adhesive generally comprises an acrylic pressure-sensitive adhesive and an active energy ray-polymerizable compound as main components. Usually, a crosslinking agent is further blended, and a photopolymerization initiator and a photosensitizer can be blended as necessary.

  In addition to the above base polymer and cross-linking agent, the pressure-sensitive adhesive layer can be used, for example, to adjust the pressure-sensitive adhesive force, cohesive force, viscosity, elastic modulus, glass transition temperature, etc. Additives such as resins, tackifier resins, silane compounds, antioxidants, antistatic agents, ultraviolet absorbers, dyes, pigments, antifoaming agents, corrosive agents, photopolymerization initiators, thermal polymerization initiators May be included. Furthermore, it can also be set as the adhesive layer which contains microparticles | fine-particles and shows light-scattering property. Examples of ultraviolet absorbers include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, and nickel complex compounds.

  In a preferred embodiment, the polarizing plate of the present invention may have a polarizer and an acrylic resin film bonded via an adhesive layer.

  The adhesive which comprises an adhesive bond layer can be arbitrarily selected and used from the thing which expresses the adhesive force with respect 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 to 10 parts by mass and more preferably 1 to 5 parts by mass with respect to 100 parts by mass 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 mass, more preferably 1 to 50 parts by mass with respect to 100 parts by mass 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.

  In a preferred embodiment, the polarizer and the acrylic resin film of the polarizing plate of the present invention may be bonded via an adhesive layer.

  In the present invention, a pressure-sensitive adhesive or an adhesive is applied to the polarizer and / or the polarizer protective film of the present invention to form a coating film, and the polarizer and the polarizer protection of the present invention are protected via the formed coating film. The polarizer and the polarizer protective film of the present invention are bonded by overlapping the film and curing the pressure-sensitive adhesive or adhesive by irradiating active energy rays or by drying, and polarizing plate of the present invention Can be obtained.

  Application of the pressure-sensitive adhesive or adhesive to the polarizer and / or the polarizer protective film of the present invention can be carried out by a known method, for example, casting method, Mayer bar coating method, gravure coating method, comma coater method. A doctor blade method, a die coating method, a dip coating method, a spraying method, or the like can be used.

  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. Moreover, what is necessary is just to determine suitably the light irradiation intensity | strength and irradiation amount of an active energy ray by the composition of the active energy ray hardening-type adhesive and adhesive agent to be used.

  The drying treatment is performed, for example, by blowing hot air, and the temperature is usually in the range of 40 to 100 ° C, preferably in the range of 60 to 100 ° C. The drying time is usually about 20 to 1200 seconds.

  The thickness of an adhesive layer is 1-50 micrometers normally, Preferably it is 5-30 micrometers. Moreover, the thickness of an adhesive bond layer is 0.01-10 micrometers normally, Preferably it is 0.01-5 micrometers. The thickness of an adhesive layer and 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. As an adhesive which comprises this adhesive layer, the thing similar to what was illustrated previously as an adhesive which can be used in order to adhere | attach a polarizer and the polarizer protective film of this invention is mentioned. When incorporated in an image display device or the like, the polarizing plate of the present invention can exhibit high visibility due to the good appearance of the resin film.

[Polarizer with release film]
The resin film of the present invention is also suitable as a release film. That is, in another embodiment of the present invention, there is provided a polarizer with a release film laminated with a release film composed of the resin film of the present invention (hereinafter also referred to as “polarizer with a release film of the present invention”). Provided.

  In the polarizer with a release film of the present invention, a release film composed of the resin film of the present invention is laminated on at least one surface of the polarizer so as to be separable. In this invention, it is preferable that a peeling film is comprised from the resin composition and peeling layer of this invention. The release layer can be formed from, for example, a release layer forming composition. The main component (resin) constituting the release layer forming composition is not particularly limited, and may be composed of known components generally used in this field.

The release film composed of the resin film of the present invention is, for example, a composition for forming a release layer diluted in a solvent on one surface of the resin film of the present invention, for example, gravure coating method, bar coating method, spray coating method, spin coating It can be produced by coating by a method such as a coating method, an air knife coating method, a roll coating method, a blade coating method, a gate roll coating method, and a die coating method. Examples of the method for heating / drying the release layer-forming composition include a method of thermally drying in a hot air drying furnace. The drying temperature is, for example, 50 ° C. or higher and 150 ° C. or lower. The drying time is, for example, 10 seconds to 5 minutes.
In this invention, the thickness of a peeling film becomes like this. Preferably it is 10-100 micrometers, More preferably, it is 20-80 micrometers. Note that the thickness of the release film can be controlled by the thickness of the resin film and the thickness of the release layer.

  As a polarizer used for the polarizer with a release film of the present invention, the same configuration as that in the polarizing plate described above can be mentioned.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these 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]
Table 1 shows the monomer unit composition and general physical properties of the copolymer (A) (polymers A-1 to A-4) used in Examples 1 to 4 and Comparative Example 1. Table 2 shows the monomer unit composition and general physical properties of the polymer (B) (polymers B-1 and B-2).
The weight average molecular weight (Mw) and number average molecular weight (Mn) of each polymer were determined by gel permeation chromatography (GPC) measurement (in terms of polymethyl methacrylate).
The MFR (measurement temperature 230 ° C., load 37.3 N) of each polymer was measured according to JIS K7210. The copolymer (A) and polymer (B) used were all colorless and transparent pellets.

The rubber elastic particles used in Examples 1 to 4 and Comparative Example 1 were all core-shell type butadiene rubber. The rubber elastic body particles used were all white (uncolored) powder. Table 3 shows the characteristics of the rubber elastic particles (rubbers 1 and 2).
The 1% weight loss temperature (° C.) and the Ca ²⁺ ion content were measured according to the following methods.

[Measurement of 1% weight loss temperature]
About 5 mg of rubber 1 and rubber 2 are placed in an aluminum pan, respectively, and the weight of the sample is weighed, and weighed under the following conditions using a differential thermothermal gravimetric simultaneous measurement device SII TG / DTA6200 (Hitachi High-Tech Science). Went.
Pan: φ5 cylindrical sample cup made of aluminum (Seiko Instruments Inc. SSC00E030)
Sample amount: about 5mg
Measurement temperature: room temperature (23 ° C.) to 400 ° C.
Temperature increase rate: 10 ° C./min Atmosphere: N ² 200 mL / min

[Measurement of Ca ²⁺ ion content]
Measured by ashing / acid dissolution / ICE AES method.

  According to the composition shown in Table 4 (each by mass), the copolymer (A), the polymer (B) and the rubber elastic particles were put into an extruder, and melt-kneaded at 230 ° C. and an average residence time of 10 minutes. Resin pellets of the thermoplastic resin composition were obtained.

[Production of resin film]
The extruder, the T die, and the first to third cooling rolls were arranged as shown in FIG. Next, the obtained resin pellets of the thermoplastic resin composition were 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.

[Calculation of reaction rate constant k]
Samples (about 5 mg) obtained by chopping the resin films of Examples 1 to 4 and Comparative Example 1 were placed in an aluminum pan, the sample weight was weighed, and the differential thermothermal gravimetric simultaneous measurement apparatus SII TG / DTA6200 (Hitachi Using High-Tech Science), the weight was measured under the following conditions.
Pan: φ5 cylindrical sample cup made of aluminum (Seiko Instruments Inc. SSC00E030)
Sample amount: about 5mg
Measurement temperature: room temperature (23 ° C.) to 500 ° C.
Temperature increase rate: 10 ° C./min Atmosphere: N ₂ 200 mL / min

The weight is plotted against the measurement time [s], a TG curve is created, the reaction rate constant k (s ⁻¹ ) is obtained from the time differential value DTG, the logarithmic value is set to lnk, and the temperature is 300 ° C. The corresponding lnk was defined as lnk (300 ° C.).

[Preparation of initial sample]
The resin pellets of Examples 1 to 4 and Comparative Example 1 were melted at 200 ° C. for 2 minutes using a press machine, and thereafter 3 at a pressure of 2 MPa while maintaining the temperature at 200 ° C. A 1 mmt press plate was produced by pressing for 2 minutes and further pressing at 15 MPa for 2 minutes. The simple substance b * of the obtained initial sample was measured according to JIS Z8781-4 using an ultraviolet-visible near-infrared spectrophotometer manufactured by JASCO Corporation. Table 5 shows the single sample b * of the initial sample as a single b * ₀ .

[Durable sample preparation]
Next, the initial sample after measuring the simple substance b * was cut into 1 cm square, and the resin was melted between a pair of molds at 260 ° C. using a press machine. A 1 mmt press plate was produced by pressing at 1 ° C. for 1 hour. Similarly to the initial sample, the simple substance b * of the obtained durable sample was measured according to JIS Z8781-4 using an ultraviolet-visible near-infrared spectrophotometer manufactured by JASCO Corporation. Table 5 shows the simple substance b * of the durable sample as the simple substance b * ₁ .

[Optical evaluation]
A change amount (Δb *) of the simple substance b * by an endurance test at 260 ° C. for 1 hour was calculated and evaluated according to the following formula.
Single unit Δb * = Single unit b * ₁ -Single unit b * ₀

In the thermoplastic resin compositions of Examples 1 to 4 in which the logarithm lnk of the reaction rate constant k (s ⁻¹ ) at 300 ° C. is 0.05 or less, the color changes even under the press conditions at 260 ° C. for 1 hour. There were few. On the other hand, in the thermoplastic resin composition of Comparative Example 1 in which the logarithm lnk of the reaction rate constant k (s ⁻¹ ) at 300 ° C. exceeded 0.05, coloring occurred by pressing at 260 ° C. for 1 hour.

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 (9)

A thermoplastic resin composition comprising a copolymer (A) comprising an aromatic vinyl monomer unit and a cyclic acid anhydride monomer unit, the reaction rate constant of the thermoplastic resin composition at 300 ° C A thermoplastic resin composition in which the logarithm of k (s ⁻¹ ) is 0.05 or less.   The polymer comprising an acrylic monomer unit, comprising a polymer (B) substantially free of an aromatic vinyl monomer unit and a cyclic acid anhydride monomer unit. The thermoplastic resin composition as described.   The thermoplastic resin composition according to claim 1 or 2, comprising 0 to 30% by mass of rubber elastic particles having an average particle diameter of 10 nm to 350 nm, based on the total mass of the thermoplastic resin composition.   A method for producing a resin film, comprising melt-kneading the thermoplastic resin composition according to any one of claims 1 to 3 at a melting temperature of 230 ° C or higher and 280 ° C or lower and forming the film into a film shape.   A method for producing a resin film, comprising melt-kneading the thermoplastic resin composition according to any one of claims 1 to 3 for a residence time of 20 minutes or more and forming the film into a film shape.   The resin film comprised from the thermoplastic resin composition in any one of Claims 1-3.   The polarizer protective film comprised from the resin film of Claim 6.   The polarizing plate by which the polarizer protective film of Claim 6 was laminated | stacked on the at least one surface of the polarizer through the adhesive layer or the adhesive bond layer.   The polarizer with a peeling film by which the peeling film comprised from the resin film of Claim 6 was laminated | stacked on the at least one surface of the polarizer.

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