JP2006241263A - Method for producing acrylic resin composition film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an acrylic resin composition film excellent in transparency, freeness from defects and optical isotropy. <P>SOLUTION: This method for producing an acrylic resin composition film comprises applying an acrylic resin composition solution containing an acrylic resin composition and an organic solvent on a support, drying the coated film and peeling the acrylic resin composition coated film from the support, where the amount of residual solvent in the acrylic resin composition coated film is made ≤5 mass%, and 180° peeling force of the coated film against the support is made 0.5-5 g/25 mm when peeling the acrylic resin composition coated film from the fixed support. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing an acrylic resin composition film, an acrylic resin composition film, and an optical film using the same.

  Acrylic resins are excellent in transparency, scratch resistance, and weather resistance, and are characterized in that birefringence due to flow orientation and residual stress during molding is less likely to occur. Taking advantage of these features, acrylic resin is used in a wide range of fields, including optical parts such as light guide plates, optical disks, and display films, automotive parts such as tail lamps and visors, weak electrical parts, signboards, displays, lighting, building materials, water tanks, and sundries. (For example, Non-Patent Document 1 and Non-Patent Document 2).

  In particular, acrylic resin films used for optical components have recently been required to have extremely high transparency, defect-free properties, optical isotropy, and heat resistance. However, the conventional melt film forming method has a high melt viscosity, high-precision filtration is difficult, and birefringence due to flow orientation is not negligible, so extremely high transparency, defect-freeness, optical isotropy, etc. It was difficult to realize. Further, when the melting temperature is increased for the purpose of lowering the melt viscosity, the acrylic resin film is colored and the colorless transparency is deteriorated, or the film defect is increased due to a gel polymer or the like.

  On the other hand, the solution casting method can lower the solution viscosity by appropriately adjusting the type of solvent and polymer concentration, etc., so it can be filtered with higher precision than filtration of molten polymer, and it has transparency and defect-free properties. It is suitable for forming a film having excellent optical isotropy. However, when an acrylic resin film is obtained by the solution casting method, when the acrylic resin solution is applied to the support and dried, and the support and the acrylic resin coating are peeled off, the solvent in the acrylic resin coating is particularly There was a problem that the smaller the amount, the more firmly the support and the acrylic resin coating film were in close contact with each other, making it difficult to peel off. As described above, when the peelability between the support and the acrylic resin coating film is poor, the haze value and appearance quality of the acrylic resin film may be reduced due to crazes (fine cracks) and defects caused by the peeling, or in the worst case. Peeling becomes impossible and even an acrylic resin film cannot be obtained. In addition, an acrylic resin film containing a large amount of residual solvent of about 5% by mass or more that has not been sufficiently dried can be easily peeled off from the support, but cannot be practically used as a film. Also, when an acrylic resin film that has not been sufficiently dried is peeled off from the support and dried again as a single film, the heat resistance of the acrylic resin film decreases due to the residual solvent, and the acrylic resin film is cooled by heat shrinkage. There is a possibility that the flatness deteriorates, for example, the resin film is wavy. Furthermore, when the peeling force at the time of peeling a support body and an acrylic resin coating film is too weak, an acrylic resin coating film peels off in the middle of drying, planarity may deteriorate, and problems, such as winding wrinkles, may arise. In order to solve such problems, the acrylic resin solution is applied on a polymer film support, dried to such an extent that it can be peeled off, and then peeled off from the polymer film support to obtain an acrylic film Is disclosed (for example, Patent Document 1).

  However, Patent Document 1 does not disclose an appropriate condition regarding the peeling force when peeling the dried coating film and the support and the amount of residual solvent in the coating film, which is very important in the solution casting method. In order to obtain an acrylic resin film excellent in transparency, defect-free property, and optical isotropy, select appropriate conditions for the amount of residual solvent and peeling force in these coatings, and make the peelability good. It is essential.

In addition, it is not preferable to improve the peelability from the acrylic resin coating film by using a support on which a release agent is applied or a release layer is provided, because the film forming cost increases. Moreover, when improving the peelability of a support body and an acrylic resin coating film using an acrylic resin solution to which a release agent is added, the release agent remaining in the finally obtained acrylic resin film is different from other members. Since there is a possibility that the adhesiveness is lowered or a film defect is caused, it is not preferable.
“Current status and future prospects of plastic films and sheets”, Fuji Chimera Research Institute, Inc. (Publisher: Ryoyoshi Omotesaki), June 4, 2004, p165-p168 "Transparent resin for optics", Technical Information Association, Inc. (Issue: Kazuhiro Takahisa), December 17, 2001, p59 JP 2003-334831 A

  An object of the present invention is to provide a method for producing an acrylic resin film that solves the above-described problems of the conventional film and is excellent in transparency, defect-free property, and optical isotropy.

  That is, in the present invention, an acrylic resin composition solution containing an acrylic resin composition and an organic solvent is applied onto a support, and after drying, the support and the acrylic resin composition coating are peeled off to form an acrylic resin composition film. In the obtaining method, the amount of the residual solvent in the acrylic resin composition coating film is 5% by mass or less, the support is fixed, and when the support and the acrylic resin composition coating film are peeled, 180 of the coating film on the support is obtained. ° A method for producing an acrylic resin composition film, wherein the peeling force is 0.5 to 5 g / 25 mm.

  In the present invention, an acrylic resin composition solution containing an acrylic resin composition and an organic solvent is applied onto a support, and after drying, the support and the acrylic resin composition coating film are peeled to obtain an acrylic resin composition film. In the method, when the residual solvent amount in the acrylic resin composition coating film is 5% by mass or less and the support and the acrylic resin coating film are peeled off, the coating film is peeled off 180 ° from the support when the support is fixed. By setting the force to 0.5 to 5 g / 25 mm, an acrylic resin composition film excellent in transparency, defect-free property, and optical isotropy could be provided.

  The acrylic resin used in the present invention is a resin obtained by polymerizing acrylic acid and its derivatives. The acrylic resin includes an unsaturated carboxylic acid monomer represented by the following structural formula (4), an unsaturated carboxylic acid alkyl ester monomer represented by the following structural formula (5), acrylamide, and acrylonitrile. Of these, polymers and copolymers of unsaturated carboxylic acid alkyl esters are preferred. The acrylic resin composition used in the present invention is a composition containing 30% by mass or more of the above acrylic resin.

(However, R ⁷ represents hydrogen or an alkyl group having 1 to 5 carbon atoms.)

(However, R ⁸ represents hydrogen or an aliphatic or alicyclic hydrocarbon group having 1 to 5 carbon atoms, and R ⁹ represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms.) Unsaturated carboxylic acid alkyl ester By polymerization of the monomer, an acrylic resin having a vinyl carboxylic acid alkyl ester unit represented by the following structural formula (6) can be obtained.

(In the above formula, R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ¹¹ represents an aliphatic or alicyclic hydrocarbon group having 1 to 5 carbon atoms.)
Preferable specific examples of the vinyl carboxylic acid alkyl ester unit include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic acid. t-butyl, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) Examples include 3-hydroxypropyl acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate. 1 type may be included independently and 2 or more types may coexist. Of these, methyl (meth) acrylate is most preferred because of its excellent thermal stability.

  Here, as content of the vinyl carboxylic-acid alkylester unit with respect to an acrylic resin, 60-100 mass% is preferable, More preferably, it is 70-100 mass%. The content of 60% by mass or more is preferable because the acrylic resin is excellent in transparency and stable with respect to heat and water.

  As the polymerization method of the acrylic resin, a known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, precipitation polymerization or the like by basically radical polymerization can be used, and from the viewpoint of fewer impurities. Solution polymerization is particularly preferred.

  The polymerization temperature of the acrylic resin is preferably 95 ° C. or lower, more preferably 85 ° C. or lower, and further preferably 75 ° C. or lower, from the viewpoint of preventing the resin from being colored and having a good color tone. The lower limit of the polymerization temperature is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of productivity taking the polymerization rate into consideration. Further, for the purpose of improving the polymerization yield or the polymerization rate, the polymerization temperature may be raised according to the progress of the polymerization. In this case as well, the upper limit temperature is preferably controlled to 95 ° C. or lower throughout the process, and the polymerization initiation temperature is increased. Is preferably performed at a relatively low temperature of 75 ° C. or lower.

  The polymerization time of the acrylic resin is preferably 1 to 6 hours, more preferably 1.5 to 3 hours from the viewpoint of production efficiency.

  The mass average molecular weight of the acrylic resin is preferably in the range of 80,000 to 150,000. When the mass average molecular weight is 80,000 or more, an acrylic resin film excellent in mechanical strength can be obtained, and when the mass average molecular weight is 150,000 or less, resin coloring can be prevented.

  The molecular weight of the acrylic resin is, for example, the amount of radical polymerization initiator such as azo compound or peroxide, or the amount of chain transfer agent such as alkyl mercaptan, carbon tetrachloride, carbon tetrabromide, dimethylacetamide, dimethylformamide, triethylamine, etc. It can be controlled by adjusting. In particular, a method of adjusting the addition amount of alkyl mercaptan as a chain transfer agent can be preferably employed from the viewpoint of stability of polymerization and ease of handling.

  Examples of the alkyl mercaptan used here include n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, and among them, t-dodecyl mercaptan, n-dodecyl. Mercaptans are preferably used.

  The addition amount of the alkyl mercaptan is preferably 0.2 to 5.0% by mass, more preferably 0.3 to 4.0% by mass, and still more preferably 0.4 to 100% by mass of the total of the monomers. It is -3.0 mass%.

  The acrylic resin composition of the present invention comprises a glutaric anhydride unit represented by the following structural formula (1), a lactone ring unit represented by the following structural formula (2), and a maleimide represented by the following structural formula (3). It is preferable to contain 20 to 40% by mass of at least one unit selected from the units based on 100% by mass of the acrylic resin in the acrylic resin composition.

(In the above formula ^(1), R 1, ^{R 2} represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)

(In said formula (2), R < ³ >, R < ⁴ >, R < ⁵ > represents a hydrogen atom or a C1-C20 alkyl group.)

(In the formula (3), R ⁶ is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group or an aromatic group.) The acrylic resin of the present invention, glutaric anhydride of the structural formula (1) Physical units, lactone ring units represented by the structural formula (2), maleimide units represented by the structural formula (3) (hereinafter, units of the structural formulas (1) to (3) are collectively referred to as cyclic units) The heat resistance can be improved. The content of these cyclic units is preferably 20 to 40% by mass, more preferably 25 to 35% by mass. When the content of the cyclic unit is 20% by mass or more with respect to the acrylic resin, the resin has excellent heat resistance and chemical resistance. Moreover, the toughness fall of resin can be suppressed as content of a cyclic unit is 40 mass% or less with respect to acrylic resin.

The glutaric anhydride unit represented by the structural formula (1) includes an unsaturated carboxylic acid monomer represented by the structural formula (4) and an unsaturated carboxylic acid represented by the structural formula (5). By heating a copolymer obtained by polymerizing an alkyl ester monomer (hereinafter, this copolymer is abbreviated as a precursor of a glutaric anhydride structural unit) in the presence or absence of an appropriate catalyst. In the precursor of the glutaric anhydride structural unit, the alcohol is dehydrated from the carboxyl group of two adjacent unsaturated carboxylic acid units, or the alcohol is desorbed from the adjacent unsaturated carboxylic acid unit and the unsaturated carboxylic acid alkyl ester unit. Release one unit of glutaric anhydride unit. In particular, from the viewpoint of heat resistance, R ¹ and R ^{2 in} the structural formula (1) are preferably hydrogen or a methyl group, and particularly preferably a methyl group.

  The blending ratio of the monomers is preferably 15 to 45% by weight, more preferably 20 to 40% by weight of the unsaturated carboxylic acid monomer, with the sum of the blended monomers being 100% by weight. Moreover, 55-85 mass% is preferable, and, as for an unsaturated carboxylic-acid alkylester monomer, More preferably, it is 60-80 mass%.

  When the content of the unsaturated carboxylic acid monomer is 15 to 45% by mass, the content of the glutaric anhydride unit is preferably 20 to 40% by mass when the precursor of the glutaric anhydride structural unit is heated. It is preferable because the acrylic resin composition is excellent in heat resistance, colorless transparency, and retention stability.

  Examples of a method for heating and dehydrating and / or dealcoholizing a glutaric anhydride structural unit precursor, that is, performing an intramolecular cyclization reaction, include a method using a heated extruder having a vent, an inert gas, and the like. A method using an apparatus that can be heated and degassed in an atmosphere or vacuum is preferable from the viewpoint of productivity.

  As a specific apparatus, for example, a single screw extruder equipped with a “unimelt” type screw, a twin screw extruder, a triaxial extruder, a continuous or batch kneader type kneader, etc. can be used. Use of a twin-screw extruder is preferable in terms of quality stability because it is easy to control continuous productivity, reaction temperature, time, and shear rate. The length / diameter ratio (L / D) of the screw of the extruder is preferably 40 or more. By setting the L / D to 40 or more, it is possible to secure a sufficient heating time for advancing the intramolecular cyclization reaction. Reducing the residual amount of saturated carboxylic acid units and obtaining a resin containing glutaric anhydride units with less bubbles in the molded product due to re-advancement of the reaction during the heat molding process, and the color tone at the time of molding retention Deterioration can be suppressed.

  Moreover, it is more preferable that the apparatus has a structure capable of introducing an inert gas such as nitrogen into them. When the intramolecular cyclization reaction by heating in the presence of oxygen tends to increase the yellowness of the resin containing glutaric anhydride units, the system can be sufficiently replaced with an inert gas such as nitrogen. preferable. As a method for introducing an inert gas such as nitrogen into the twin screw extruder, for example, a method of connecting a pipe from the upper part and / or the lower part of the hopper and flowing an inert gas of about 10 to 100 L / min.

  The heating temperature for the intramolecular cyclization reaction is preferably 180 to 300 ° C, more preferably 200 to 280 ° C, from the viewpoint that the reaction proceeds smoothly.

  The heating time for the intramolecular cyclization reaction may be appropriately set according to the desired copolymer composition, but is usually preferably 1 to 60 minutes, more preferably 2 to 30 minutes, and even more preferably 3 to 20 minutes. It is.

  In addition, when heating the intramolecular cyclization reaction, it is also preferable to add one or more of an acidic catalyst, an alkaline catalyst, and a salt catalyst. Examples of the acidic catalyst include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid, phosphorous acid, phenylphosphonic acid, methyl phosphate, and the like. Examples of the basic catalyst include metal hydroxides, amines, imines, alkali metal derivatives, alkoxides and the like. Examples of the salt-based catalyst include acetic acid metal salt, stearic acid metal salt, metal carbonate salt, ammonium hydroxide salt and the like. Among them, a basic catalyst or a salt-based catalyst containing an alkali metal can be preferably used because it exhibits an excellent reaction promoting effect with a relatively small addition amount. Specifically, alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, sodium methoxide, sodium ethoxide, sodium phenoxide, potassium methoxide, potassium ethoxide, alkoxide compounds such as potassium phenoxide, Examples thereof include organic carboxylates such as lithium acetate, sodium acetate, potassium acetate, and sodium stearate. Among them, sodium hydroxide, sodium methoxide, lithium acetate, and sodium acetate can be preferably used.

  The addition amount of these catalysts is preferably about 0.01 to 1% by mass with respect to 100% by mass of the precursor of the glutaric anhydride structural unit. When it is 0.01% by mass or more, a catalytic function is exhibited, and when it is 1% by mass or less, coloring of the resin and a decrease in transparency can be prevented.

  The lactone ring unit represented by the structural formula (2) is a polymer obtained by polymerizing an α-hydroxymethyl acrylate monomer represented by the following structural formula (7) (hereinafter, this polymer). Is abbreviated as a lactone ring precursor) in the presence or absence of a suitable catalyst, and the lactone ring unit can be obtained by eliminating alcohol or water.

(In said formula (7), R <^12> , R < ¹³ > represents a hydrogen atom or a C1-C5 alkyl group.)

As a method for heating the lactone ring precursor to remove alcohol or water and performing an intramolecular cyclization reaction, the same method as the method for performing the intramolecular cyclization reaction of the glutaric acid precursor can be used. . The intramolecular cyclization reaction of the lactone ring precursor is performed by dissolving the lactone ring precursor in an organic solvent such as ethyl acetate, chloroform, tetrahydrofuran, or dimethyl sulfoxide, and then adding an esterification catalyst or a transesterification catalyst. It can also be made.

  The maleimide unit represented by the structural formula (3) includes, for example, N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, Ni-propylmaleimide, Nn-butylmaleimide, Ni -Butylmaleimide, Ns-butylmaleimide, Nt-butylmaleimide, Nn-pentylmaleimide, Nn-hexylmaleimide, Nn-heptylmaleimide, Nn-octylmaleimide, N-laurylmaleimide N-alkyl substituted maleimide monomers such as N-stearylmaleimide, N-cyclopropylmaleimide, N-cyclobutylmaleimide, N-cyclohexylmaleimide, N-methylcitraconimide, N-phenylmaleimide, N- (2- Methylphenyl) maleimide, N- (2-ethyl) phenylmale N- (2-Isopropyl) phenylmaleimide, N- (3-methylphenyl) maleimide, N- (3-ethylphenyl) maleimide, N- (4-methylphenyl) maleimide, N- (4-ethylphenyl) Maleimide, N- (2,6-dimethylphenyl) maleimide, N- (2,6-diethylphenyl) maleimide, N- (2,6-diisopropylphenyl) maleimide, N- (2,4,6-trimethylphenyl) Known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization of one or more monomers selected from N-phenyl-substituted maleimide monomers such as maleimide and N-carboxyphenylmaleimide Can be obtained by polymerization.

  The above cyclic unit of glutaric anhydride unit, lactone ring unit, and maleimide unit may be contained alone or in combination of two or more kinds with respect to the acrylic resin of the present invention.

  The acrylic resin composition of the present invention preferably has a glass transition temperature (Tg) of 120 ° C. or higher. When the glass transition temperature (Tg) of the acrylic resin composition is 120 ° C. or higher, an acrylic resin composition film excellent in heat resistance and dimensional stability under high temperature environment is preferable. The upper limit of the glass transition temperature (Tg) is preferably higher, but is preferably 160 ° C. or lower from the viewpoint of workability.

  In order to set the glass transition temperature (Tg) within the above range, the content of the cyclic unit relative to the acrylic resin composition is preferably 20 to 40% by mass. The glass transition temperature (Tg) of the present invention is measured at a heating rate of 20 ° C./min using a differential scanning calorimeter (for example, DSC-7 manufactured by Perkin Elmer), and is JIS-K7121 (1987). In accordance with the method for obtaining the midpoint glass transition temperature in Section 9.3, a straight line that is equidistant from the extended straight line of each base line of the measurement chart and the curve of the stepwise change portion of the glass transition intersect. The temperature of the point.

  The acrylic resin composition of the present invention preferably contains acrylic elastic particles from the viewpoint of improving the toughness of the acrylic resin composition film.

  The rubbery polymer constituting the acrylic elastic particles has an acrylic component such as an ethyl acrylate unit or a butyl acrylate unit as an essential component, and other preferable components include a silicone component such as a dimethylsiloxane unit or a phenylmethylsiloxane unit. Styrene components such as styrene units and α-methylstyrene units, nitrile components such as acrylonitrile units and methacrylonitrile units, conjugated diene components such as butanediene units and isoprene units, urethane components or ethylene components, propylene components, isobutene components, etc. Can be mentioned. Among these, those composed of an acrylic component, a silicone component, a styrene component, a nitrile component, and a conjugated diene component are preferable. A rubber elastic body composed of a combination of two or more of these components is also preferable. For example, a rubber elastic body composed of an acrylic component and a silicone component, a rubber elastic body composed of an acrylic component and a styrene component, acrylic Examples thereof include a rubber elastic body composed of a component and a conjugated diene component, a rubber elastic body composed of an acrylic component, a silicone component and a styrene component. In addition to these components, those containing a crosslinkable component such as a divinylbenzene unit, an allyl acrylate unit, or a butylene glycol diacrylate unit are also preferred. Among these, a combination of an acrylic acid alkyl ester unit and an aromatic vinyl-based unit is preferable. Alkyl acrylate units, especially butyl acrylate, are extremely effective in improving toughness, and the refractive index of acrylic elastic particles can be adjusted by copolymerizing aromatic vinyl units such as styrene. The copolymerization ratio of butyl acrylate and styrene is preferably 10 to 50% by mass of styrene with respect to 50 to 90% by mass of butyl acrylate, more preferably acrylic acid, based on 100% by mass of the entire acrylic elastic particles. It is 20-30 mass% of styrene with respect to 70-80 mass% of butyl.

  The refractive index of the acrylic elastic particles is preferably adjusted so that the refractive index difference from the acrylic resin composition is 0.01 or less. In order to satisfy such a refractive index condition, a method of adjusting the monomer composition ratio of the acrylic resin composition and / or a method of adjusting the composition ratio of the rubbery polymer or monomer of the acrylic elastic particles Thus, the refractive index difference can be reduced, and an acrylic resin composition film excellent in transparency can be obtained. In particular, acrylic elastomer particles such as butyl acrylate are copolymerized with aromatic vinyl units such as styrene, and the copolymerization ratio is adjusted, whereby acrylic elastic particles having a small refractive index difference from the acrylic resin composition are obtained. Obtainable.

  The average particle diameter of the acrylic elastic particles is preferably 70 to 300 nm, more preferably 100 to 200 nm. By setting the average particle size to 70 nm or more, toughness and impact resistance can be improved, and by setting the average particle size to 300 nm or less, a decrease in heat resistance of the acrylic resin composition can be suppressed.

  The content of the acrylic elastic particles with respect to the acrylic resin composition is preferably 10 to 30% by mass, and more preferably 10 to 20% by mass. By setting the content of the acrylic elastic particles to the acrylic resin composition within the above range, a film having appropriate flexibility is obtained, and a film excellent in workability such as winding property and slit property and heat resistance is obtained. be able to.

  When the acrylic resin composition contains acrylic elastic particles, an acrylic resin layer having a glass transition temperature of 60 ° C. or higher is provided on the surface layer of the acrylic elastic particles or a vinyl monomer from the viewpoint of improving dispersibility. It is preferable to use acrylic elastic particles obtained by graft copolymerization.

  In the so-called core-shell type acrylic elastic particles provided with an acrylic resin layer having a glass transition temperature of 60 ° C. or higher on the surface layer, an acrylic resin having a glass transition temperature of 60 ° C. or higher constituting the shell portion of the outer layer may be used. Those containing acid alkyl ester units and unsaturated carboxylic acid units are preferred. When such core-shell type acrylic elastic particles are added to the acrylic resin composition and heated, the affinity with the acrylic resin as the matrix portion is good and the dispersibility is improved.

  As a monomer used as a raw material of the unsaturated carboxylic acid alkyl ester unit, (meth) acrylic acid alkyl ester is preferable, and methyl (meth) acrylate is more preferably used.

  Moreover, as a monomer used as the raw material of an unsaturated carboxylic acid-type unit, (meth) acrylic acid is preferable and methacrylic acid is more preferably used.

  The mass ratio of the core part to the shell part of the core-shell type acrylic elastic particles is preferably 50% to 90% by mass of the core part, where the total mass of the core-shell type acrylic elastic particles is 100% by mass. 60 to 80% by mass is more preferable.

  Typical core-shell type acrylic elastic particles include, for example, “Metablene” manufactured by Mitsubishi Rayon Co., Ltd., “Kane Ace” manufactured by Kaneka Chemical Co., Ltd., “Paraloid” manufactured by Kureha Chemical Co., Ltd., and “Acryloid” manufactured by Rohm and Haas Co. , “Staphyroid” manufactured by Gantz Kasei Kogyo Co., Ltd., “Parapet SA” manufactured by Kuraray Co., Ltd., and the like may be used alone or in combination of two or more.

  In the graft copolymerization type acrylic elastic particles obtained by graft copolymerization with a vinyl monomer, the vinyl monomer may be an unsaturated carboxylic acid ester monomer having a vinyl group or a vinyl group. It can be selected from unsaturated carboxylic acid monomers, aromatic vinyl monomers, and the like. Further, other vinyl monomers may be copolymerized according to the compatibility with the rubbery polymer constituting the acrylic elastic particles and the acrylic resin as the matrix portion.

  The amount of the vinyl monomer to be applied to the acrylic elastic particles is a mass ratio of the rubber polymer to the vinyl monomer (rubber polymer: vinyl monomer), (10 to 80): (20 to 90) is preferable, (20 to 70): (30 to 80) is more preferable, and (30 to 60): (40 to 70) is more preferable. By setting the vinyl monomer in the range of 20 to 90% by mass, elastic particles having moderate flexibility can be obtained.

  The graft copolymer type acrylic elastic particles may contain a component derived from a vinyl monomer that is not graft copolymerized, but the graft ratio is 10 to 100% from the viewpoint of impact strength. It is preferable. Here, the graft ratio is a mass ratio of a graft copolymerized vinyl monomer provided to the rubber polymer. Further, the intrinsic viscosity of the ungrafted copolymer is not particularly limited, but a methyl ethyl ketone solvent having an intrinsic viscosity of 0.1 to 0.6 dl / g measured at 30 ° C. has an impact strength and moldability. It is preferable from the viewpoint of balance.

  As a method for obtaining the graft copolymer type acrylic elastic particles, polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be used.

  The particle diameter of the core-shell type or graft copolymer type acrylic elastic particles is measured by a method such as cross-sectional observation with a transmission electron microscope for rubbery polymers excluding the shell part and graft copolymer part. it can. The content of the core-shell type or graft copolymer type acrylic elastic particles can be measured from the amount of insoluble components after the acrylic resin composition is dissolved in an organic solvent such as acetone.

  As a method of blending acrylic elastic particles and other additives into the acrylic resin composition, for example, after blending the acrylic resin or acrylic resin composition and other additive components in advance, usually at 200 to 350 ° C., uniaxially or A method of uniformly melt-kneading with a twin-screw extruder can be used.

  In the melt-kneading, a cyclization reaction of unsaturated carboxylic acid monomer units such as shell portions imparted to the acrylic elastic particles and unsaturated carboxylic acid alkyl ester monomer units can be performed simultaneously.

  The acrylic resin composition may contain vinyl units within a range not impairing the effects of the present invention, but the content of styrene units such as styrene and α-methylstyrene should be 0 to 1% by mass. Is preferable, and more preferably 0 to 0.1% by mass. By making content of a styrene-type unit 1 mass% or less, a heat resistant and transparency fall can be prevented.

In addition, the acrylic resin composition of the present invention includes polyethylene, polypropylene, polyamide, polyphenylene sulfide, polyether ether ketone, polyester, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyetherimide, as long as the object of the present invention is not impaired. Thermosetting resins such as thermoplastic resins such as phenol, melamine, polyester, silicone, and epoxy may be contained. In addition, hindered phenol-based, benzotriazole-based, benzophenone-based, benzoate-based, and cyanoacrylate-based UV absorbers or antioxidants, lubricants or plasticizers such as higher fatty acids, acid esters, acid amides and higher alcohols, Release agents such as montanic acid, its salts, its esters, its half esters, stearyl alcohol, stearamide and ethylene wax, anti-coloring agents such as phosphites and hypophosphites, halogen-based, phosphorus-based and silicone-based It may contain additives such as non-halogen flame retardants, nucleating agents, amine-based, sulfonic acid-based, polyether-based antistatic agents, pigments and other colorants. In addition, inorganic particles such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , CaSO ₄ , BaSO ₄ , CaCO ₃ , carbon black, zeolite, and other metal fine powders, silicone particles, polyimide particles, and Teflon (registered trademark) particles. In addition, organic particles such as crosslinked copolymer particles, crosslinked polyester particles, and crosslinked polystyrene particles may be contained. The content of these resins and additives other than the acrylic resin with respect to the acrylic resin composition is appropriately adjusted depending on the use, but it affects the transparency and defect-free characteristics that are the characteristics of the acrylic resin composition film of the present invention. It is preferable to contain in the range which does not affect this, and it is thought that it is preferable that it is 10 mass% or less practically.

  The method for producing an acrylic resin composition film of the present invention comprises applying an acrylic resin composition solution containing the above acrylic resin composition and an organic solvent on a support, drying, and then drying the support and the acrylic resin composition coating film. In the method of peeling to obtain an acrylic resin composition film, the residual solvent amount in the acrylic resin composition coating film is set to 5% by mass or less, and the support is fixed when peeling the support and the acrylic resin composition coating film. It is necessary that the 180 ° peeling force of the coating film with respect to the support is 0.5 to 5 g / 25 mm. Here, the 180 ° peeling force of the acrylic resin composition coating film on the support when the support is fixed is the stress at the time of peeling in the 180 ° direction with respect to the plane of the support on which one end of the acrylic resin coating film is fixed. (Hereinafter abbreviated as coating film peeling force). Conversely, the stress at the time of peeling in the direction of 180 ° with respect to the acrylic resin composition coating plane on which one end of the support is fixed is the 180 ° peeling force of the support with respect to the acrylic resin composition coating (hereinafter referred to as the support). (Abbreviated as peeling force). In addition, the evaluation method of peeling force is mentioned later.

  When the coating film peeling force is less than 0.5 g, the acrylic resin composition coating film may be peeled off during drying, and the flatness of the acrylic resin composition film may deteriorate, or problems such as winding wrinkles may occur. When the coating film peeling force exceeds 5 g / 25 mm, there is a tendency that the haze value of the acrylic resin composition film is deteriorated or scratched due to crazing (fine cracks) generated during peeling. The coating film peeling force is more preferably in the range of 1 to 4 g / 25 mm, and still more preferably in the range of 1 to 3 g / 25 mm. The support peeling force is preferably within the range of 0.5 to 5 g / 25 mm, more preferably within the range of 1 to 4 g / 25 mm, and even more preferably within the range of 1 to 3 g / 25 mm. It is.

  In the present invention, the residual solvent amount in the acrylic resin composition coating film needs to be 5% by mass or less. However, if the residual solvent amount exceeds 5% by mass, the winding property of the film deteriorates due to blocking. Or the organic solvent bleeds out over time, and problems such as a decrease in adhesion to other members are likely to occur. In the present invention, the residual solvent amount in the acrylic resin composition coating film is defined as being determined by the following evaluation method. Using a thermal mass measuring device, the thermal loss of the acrylic resin composition film was measured under a temperature increase rate of 10 ° C./min in a nitrogen atmosphere, and the following formula was calculated from the mass at 35 ° C. and the mass at 200 ° C. Determine the amount of residual solvent.

  Residual solvent amount in acrylic resin composition coating film (mass%) = ((mass at 35 ° C.−mass at 200 ° C.))) / Mass at 35 ° C.) × 100 in acrylic resin composition coating film The amount of residual solvent is more preferably 3% by mass or less, further preferably 2% by mass or less, and most preferably 1% by mass or less. And Although it is preferable that the residual solvent amount in the acrylic resin composition coating film is low, it is considered to be about 100 ppm in practice.

  In the present invention, any of a polymer film, a drum, an endless belt and the like may be used as a support on which the acrylic resin composition solution is applied, but the peelability between the dried acrylic resin composition coating film and the support is good. Therefore, it is preferable to use a polymer film as a support. The polymer film support is not particularly limited as long as it is resistant to the organic solvent used in the acrylic resin composition solution. For example, a polyethylene terephthalate film, a polyethylene naphthalate film, a polypropylene film, a polyethylene film, A polyphenylene sulfide film, an aramid film, a polyimide film, etc. are mentioned. Among these, a polyethylene terephthalate film excellent in balance of rigidity, thickness unevenness, defect-free property, cost, etc. is preferable.

  The peeling force between the support and the acrylic resin composition coating film can be adjusted by controlling the type of the support or the organic solvent, the amount of residual solvent in the acrylic resin composition coating film, and the like.

  The method for applying the acrylic resin composition solution to the support is appropriately selected depending on the viscoelasticity of the acrylic resin composition solution, the coating thickness of the acrylic resin composition, the type of the support, the organic solvent used, etc. Examples of the coating method include a rotary roll coater, a reverse roll coater, a gravure coater, a knife coater, a blade coater, a rod coater, an air doctor coater, a curtain coater, a fountain coater, a kiss coater, a screen coater, a comma coater, and a slit die coater.

  Here, in the present invention, the method of applying an acrylic resin composition solution containing an acrylic resin composition and an organic solvent on a support and drying can be carried out by the following method, but is not limited thereto. Absent.

  The acrylic resin composition obtained by the above method includes halogenated hydrocarbon organic solvents such as methylene chloride, ethylene chloride and chloroform, ketone organic solvents such as acetone and methyl ethyl ketone, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, N-methyl- It can be dissolved in an organic solvent such as 2-pyrrolidone to obtain an acrylic resin composition solution. These organic solvents may be used alone or in combination of two or more. When the acrylic resin composition is prepared by solution polymerization, this polymerization solution may be used as it is as an acrylic resin composition solution for film formation, or once isolated acrylic resin composition is dissolved in the organic solvent. An acrylic resin composition solution for film formation may be used. In addition, inorganic and / or organic additives such as antioxidants, heat stabilizers, ultraviolet absorbers, and nucleating agents are added to the acrylic resin composition solution as long as the object of the present invention is not impaired. Also good.

  In addition to the above organic solvents, the organic solvent of the acrylic resin composition solution includes hydrocarbon organic solvents such as cyclohexane, benzene, toluene, xylene, styrene, cyclopentane, methanol, ethanol, isopropyl alcohol, n-butanol, tert. -Alcohol organic solvents such as butyl alcohol, ether organic solvents such as dimethyl ether, diethyl ether, and butyl ether, ester organic solvents such as methyl acetate, ethyl acetate, and n-butyl acetate, ethyl cellosolve, cellosolve acetate, tert-butyl cellosolve, etc. One kind or a mixture of two or more kinds selected from polyhydric alcohol organic solvents may be used. By mixing these organic solvents, the viscoelasticity and surface tension of the acrylic resin composition solution change, and the surface properties and drying characteristics of the acrylic resin composition coating film, and the releasability from the support are improved. It can be planned. However, it should be noted that when an organic solvent having a poor solubility of the acrylic resin composition is mixed in a large amount, the stability of the acrylic resin composition solution is deteriorated and the acrylic resin composition may be precipitated.

  The concentration of the acrylic resin composition solution is appropriately adjusted according to the type of the organic solvent and the intended coating thickness of the acrylic resin composition, but is preferably in the range of 5 to 40% by mass. More preferably, it is in the range of 10 to 30% by mass. In the present invention, the concentration of the acrylic resin composition solution is the concentration of the acrylic resin composition with respect to the entire acrylic resin composition solution. When the concentration of the acrylic resin composition solution is less than 5% by mass, the viscosity is low, and the flatness of the acrylic resin composition film is deteriorated due to the convection of the organic solvent in the initial drying stage of the acrylic resin composition coating film. This is not preferable because productivity is reduced, such as requiring a long time for drying. On the other hand, if the concentration of the acrylic resin composition solution exceeds 40% by mass, the viscosity is high, handling properties are deteriorated, and problems such as difficulty in high-precision filtration occur.

  In order for the acrylic resin composition solution to have favorable film defects and haze values, it is preferable to remove foreign matters by filtration. Examples of the filter used for such filtration include a filter made of a polymer such as a wire mesh, sintered metal, porous ceramic, glass, polypropylene resin or polyethylene resin, or a filter combining two or more of the above materials.

  The filtration accuracy of this acrylic resin composition solution is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. The smaller the filtration accuracy of the acrylic resin composition solution, the better. However, too low a filter accuracy is not preferable because the frequency of filter replacement due to clogging increases and productivity decreases. About 0.1 μm is considered appropriate as the lower limit of the filtration system of the acrylic resin composition solution.

  The acrylic resin composition solution prepared as described above is applied onto a support by the above-described application method, and the acrylic resin composition coating film is dried and peeled off from the support to obtain an acrylic resin composition film.

  When a polymer film is used as the support, the film thickness is preferably 50 to 200 μm, more preferably 100 to 150 μm. When the film thickness of the support is less than 50 μm, the rigidity of the film is low, and wrinkles are likely to occur at the coating or drying stage, so that problems such as deterioration of the flatness of the acrylic resin composition film tend to occur. Moreover, when the film thickness of a support body exceeds 200 micrometers, it is not economical, and since problems, such as it being difficult for heat to transmit to an acrylic resin composition coating film, are not preferable.

  The acrylic resin composition film of the present invention is preferably composed of at least three stages of initial drying, intermediate drying, and final drying in the drying process of the acrylic resin composition coating film coated on the support. Of the acrylic resin composition was Tg (° C), the initial drying temperature was T1 (° C), the intermediate drying temperature was T2 (° C), and the final drying temperature was T3 (° C). Sometimes, the temperature in each drying step is preferably the following formulas (I) to (III).

T1 (° C.) ≦ (bp−10) (° C.) (I)
(Tg-40) (° C.) ≦ T2 (° C.) ≦ Tg (° C.) (II)
Tg (° C.) <T3 (° C.) ≦ (Tg + 40) (° C.) (III)
The drying conditions of the acrylic resin composition coating applied to the support are set appropriately depending on the drying method, the organic solvent used, the viscoelasticity of the acrylic resin composition solution, the glass transition temperature of the acrylic resin composition, and the like. Although it should be, when the initial drying temperature exceeds the boiling point of the organic solvent to be used, the above-mentioned formula (I) is preferable because the acrylic resin composition film is liable to be foamed due to foaming. The initial drying temperature T1 (° C.) is more preferably T1 (° C.) ≦ (bp-15) (° C.), and further preferably T1 (° C.) ≦ (bp-20) (° C.). If the initial drying temperature T1 (° C.) is too low, it takes a long time to dry the acrylic resin composition coating film and the productivity is poor, so the lower limit is considered to be about 10 ° C.

  Further, the intermediate drying temperature and the final drying temperature are the above formulas (II) and (III) in order to reduce the residual solvent amount of the acrylic resin composition coating film, and to suppress the defects and flatness of the acrylic resin composition film due to foaming. ) Is preferable.

  Moreover, the drying process may further increase the drying process comprising the above three stages of initial drying, intermediate drying, and final drying. In this case, the drying temperature is preferably raised stepwise or continuously from the viewpoint of suppressing foaming. The drying time for each drying step is preferably about 1 to 120 minutes.

  The drying method for the acrylic resin composition coating film is selected according to the organic solvent used, the viscoelasticity of the acrylic resin composition solution, the glass transition temperature of the acrylic resin composition, the thickness of the acrylic resin composition coating film, etc. Although it should be, drying methods, such as hot air injection, a drum type, infrared rays, a microwave (induction heating), electromagnetic induction heating, an ultraviolet-ray, an electron beam, are mentioned.

  The acrylic resin composition coating film may be dried on the support until final drying, or the support and the acrylic resin composition coating film may be peeled off during drying and dried again. However, in the case of drying again after peeling, if the temperature is too high, the acrylic resin film may be corrugated due to heat shrinkage and flatness may be deteriorated. Therefore, it is preferable to perform the final drying on the support.

  The acrylic resin composition film may be stretched during or after drying. The stretching temperature is preferably within a range of ± 30 ° C. of the glass transition temperature of the acrylic resin composition. In addition, the draw ratio is preferably in the range of 1.2 to 9, more preferably in the range of 2 to 6, in terms of the ability to stably form an acrylic resin composition film having excellent mechanical properties. . The area magnification is defined as a value obtained by dividing the area of the acrylic resin composition film after stretching by the area of the acrylic resin composition film before stretching.

  The acrylic resin composition film of the present invention may be a single layer film or a laminated film, and in the case of making a laminated film, for example, a method of once forming one layer and forming another layer thereon, A method of laminating in a die or a composite tube may be used.

  The acrylic resin composition film of the present invention needs to have a haze value of 2% or less, more preferably 1.5% or less, and even more preferably 1% or less. The haze value of such an acrylic resin composition film is measured by a method based on JIS-K7136-2000. When the haze value of the acrylic resin composition film is 2% or less, a good acrylic resin composition film with little loss of transmitted light can be obtained in optical applications where transparency is required.

  As a method of reducing the haze value, the method for producing the acrylic resin composition film of the present invention is important, and the coating film peeling force when peeling the support and the acrylic resin composition coating film is 0.5. It is important that the content is within the range of ˜5 g / 25 mm, but further, (1) removing foreign matter from the acrylic resin composition, and (2) improving the toughness of the acrylic resin composition film, etc. In order to reduce the difference in the refractive index between the acrylic resin composition and the acrylic elastic particles, and (3) to prevent the surface haze from being deteriorated due to the transfer on the surface of the support, a support having excellent surface smoothness is required. It is preferable to use it. Here, the foreign substance in the present invention refers to a composition other than the above-mentioned acrylic resin composition excluding intentional additives, and refers to a substance having a size of 1 μm or more as a simple substance or an aggregate. Examples of such foreign substances include residual monomers and dust mixed during polymerization or film formation. In addition, although the minimum of the haze value of an acrylic resin composition film is not specifically limited, It is thought about 0.1% practically.

  The residual solvent amount of the acrylic resin composition film of the present invention is required to be 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and most preferably 1% by mass or less. . The residual solvent amount of the acrylic resin film can be determined by the same evaluation method as the residual solvent amount in the acrylic resin composition coating film. It is preferable that the residual solvent amount of the acrylic resin composition film is 5% by mass or less because the heat resistance and winding property of the acrylic resin composition film, adhesion to other members, and the like can be improved. Although it is preferable that the residual solvent amount of the acrylic resin composition film is low, the lower limit is considered to be about 100 ppm in practice.

  The thickness of the acrylic resin composition film of the present invention is preferably in the range of 10 to 100 μm, more preferably in the range of 20 to 90 μm, and still more preferably in the range of 30 to 80 μm. The thickness of the acrylic resin composition film should be adjusted as appropriate depending on the application, necessary characteristics, handling properties, etc., but if the thickness of the acrylic resin composition film is less than 10 μm, the handling properties are poor and it is torn during film formation. The yield may be deteriorated, for example, when the thickness exceeds 100 μm, and when the acrylic resin composition coating film is difficult to dry, productivity is reduced, defects due to foaming are increased, and transparency is increased. It is not preferable because it decreases.

The acrylic resin composition film of the present invention preferably has a retardation of 10 nm or less with respect to light having a wavelength of 550 nm, more preferably 5 nm or less, and even more preferably 2 nm or less. When the phase difference with respect to light having a wavelength of 550 nm is 10 nm or less, it can be suitably used as an optical isotropic film for protective film applications such as polarizing plates and optical disks. In applications where optical isotropy is required, it is preferable that the phase difference with respect to light having a wavelength of 550 nm is smaller, but the lower limit is considered to be about 0.1 nm in practice. In order to obtain such an optically isotropic acrylic resin film, it is effective not to introduce an additive or a copolymer component that develops a phase difference, or to reduce the draw ratio during film formation. It is. In addition, the phase difference with respect to the light beam with a wavelength of 550 nm of the present invention is determined by using an automatic birefringence meter (KOBRA-21ADH) manufactured by Oji Scientific Co., Ltd. The phase difference with respect to the light beam with a wavelength of 548.3 nm, the phase difference with respect to the light beam with a wavelength of 628.2 nm, and the phase difference with respect to the light beam with a wavelength of 752.7 nm are measured. The coefficients of a to d of the dispersion formula (R (λ) = a + b / λ ² + c / λ ⁴ + d / λ ⁶ ) are obtained, and the wavelength 550 nm (λ = 550) is substituted into the Cauchy wavelength dispersion formula. Value.

The acrylic resin composition film of the present invention is an acrylic resin with respect to light having a wavelength of 590 nm, where the refractive index in the direction of the orthogonal axis in the plane of the acrylic resin composition film is nx and ny (where nx ≧ ny). When the refractive index in the thickness direction of the composition film is nz and the thickness of the acrylic resin composition film is d (nm), the thickness direction retardation Rth defined by the following formula is preferably 30 nm or less, more preferably Is 20 nm or less, more preferably 10 nm or less, and most preferably 5 nm or less. When the retardation Rth in the thickness direction of the acrylic resin composition film is 30 nm or less, it becomes an acrylic resin composition film excellent in not only the optical isotropy in the film plane but also the optical isotropy in the thickness direction. It can be used more suitably for protective film applications such as polarizing plates and optical disks. In applications that require optical isotropy in the thickness direction, it is preferable that the thickness direction retardation Rth is small, but the lower limit is considered to be about 0.1 nm in practice. In order to obtain such an acrylic resin composition film having a small thickness direction retardation Rth, it is necessary not to introduce an additive or a copolymerization component that expresses a thickness direction retardation, or in-plane or thickness of the film. It is effective to reduce the draw ratio during film formation in the direction.
Thickness direction retardation Rth (nm) = d × {(nx + ny) / 2−nz}
The acrylic resin composition film of the present invention preferably has a total light transmittance of 91% or more, more preferably 92% or more. By setting the total light transmittance to 91% or more, the effect of improving the luminance can be obtained. The total light transmittance of such an acrylic resin composition film is measured by a method based on JIS-K7361-1-1996. In order to obtain such an acrylic resin composition film having a total light transmittance, it is effective not to introduce an additive or copolymerization component that absorbs and scatters visible light.

  The acrylic resin composition film of the present invention preferably has a Young's modulus in at least one direction of 1 GPa or more, more preferably 2 GPa or more. It is particularly preferable that the Young's modulus in all directions is 2 GPa or more. It is preferable for the Young's modulus of the acrylic resin composition film to be 1 GPa or more because distortion of the acrylic resin composition film due to stress during processing or use can be suppressed. The Young's modulus of such an acrylic resin composition film is measured by a method based on JIS-C2318. The upper limit of the Young's modulus of the acrylic resin composition film is not particularly limited, but in reality, it is considered to be about 5 GPa. In order to obtain an acrylic resin composition film having such a Young's modulus, the molecular weight of the acrylic resin, the content of the cyclic unit, the composition of the acrylic elastic particles, the particle diameter, the addition amount, and the like may be appropriately adjusted.

  In the acrylic resin composition film of the present invention, the elongation at break in at least one direction is preferably 10% or more, and more preferably 15% or more. Further, the breaking elongation in the orthogonal direction is more preferably 10% or more. When the breaking elongation of the acrylic resin composition film is 10% or more, the acrylic resin composition film has appropriate flexibility, film tearing during film formation and processing is reduced, and workability such as slitting properties is improved. It is preferable because it improves. The breaking elongation of such an acrylic resin composition film is measured by a method based on JIS-C2318. The upper limit of the elongation at break of the acrylic resin composition film is not particularly limited, but it is considered that it is practically about 50%. In order to obtain an acrylic resin composition film having such elongation at break, the molecular weight of the acrylic resin and the content of cyclic units, the composition of the acrylic elastic particles, the particle diameter, the added amount, and the dispersion in the acrylic resin composition film The state and the like may be adjusted as appropriate.

The acrylic resin composition film of the present invention preferably has a moisture absorption rate of 3% or less at 25 ° C. and a relative humidity of 75%, more preferably 2% or less, and even more preferably 1% or less. It is preferable for the acrylic resin composition film to have a moisture absorption rate of 3% or less because a change in characteristics due to a change in humidity during processing or use is suppressed. In order to obtain an acrylic resin composition film having such a moisture absorption rate, it is necessary to adjust the molecular weight of the acrylic resin and the content of the cyclic unit, or to prevent the introduction of hydrophilic additives and polymers. It is valid. The moisture absorption rate of such an acrylic resin composition film is measured by the following method. First, about 0.5 g of an acrylic resin composition film is collected, heated at 105 to 120 ° C. for 3 hours for dehumidification, and then cooled to 25 ° C. so as not to absorb moisture, such as by cooling while introducing nitrogen gas. Then, the acrylic resin composition film mass is accurately weighed to the nearest 0.1 mg (the mass at this time is defined as W0). Next, the acrylic resin composition film is allowed to stand for 48 hours in an atmosphere of 25 ° C. and a relative humidity of 75%, and the subsequent mass is accurately weighed (the mass at this time is defined as W1). Find the rate. In addition, although the one where the moisture absorption rate of an acrylic resin composition film is lower is preferable, realistically, a minimum is considered to be about 0.1%.
Moisture absorption rate (%) = ((W1-W0) / W1) × 100.

The acrylic resin composition film of the present invention preferably has a coefficient of thermal expansion of 100 ppm / ° C. or less, more preferably 80 ppm / ° C. or less, in a temperature range of 25 ° C. to 80 ° C. In order to obtain an acrylic resin composition film having such a thermal expansion coefficient, the molecular weight of the acrylic resin, the content of the cyclic unit, the composition of the acrylic elastic particles, the particle diameter, the addition amount, and the like may be appropriately adjusted. It is preferable that the thermal expansion coefficient at 25 ° C. to 80 ° C. of the acrylic resin composition film is 100 ppm / ° C. or less because dimensional changes and characteristic changes due to temperature changes during processing or use are suppressed. The thermal expansion coefficient of such an acrylic resin composition film is measured in the temperature lowering process after the acrylic resin composition film is heated to 100 ° C. using a push rod differential thermal expansion meter (TMA). The initial acrylic resin composition film length at a temperature of 25 ° C. and a relative humidity of 65% is L0, the acrylic resin composition film length at a temperature T1 (= 80 ° C.) is L1, and the acrylic resin composition at a temperature T2 (= 25 ° C.). A physical film length is set to L2, and a thermal expansion coefficient is calculated | required with the following formula | equation.
Thermal expansion coefficient (ppm / ° C.) = (((L1-L2) / L0) / (T1-T2)) × 10 ⁶ .

The acrylic resin composition film of the present invention preferably has a humidity expansion coefficient of 100 ppm /% RH or less, more preferably 80 ppm /% RH or less at an environmental temperature of 25 ° C. and a humidity range of 30% RH to 85% RH. preferable. In order to obtain an acrylic resin composition film having such a humidity expansion coefficient, the molecular weight of the acrylic resin, the content of the cyclic unit, the composition of the acrylic elastic particles, the particle diameter, the addition amount, and the like may be appropriately adjusted. It is preferable that the humidity expansion coefficient of the acrylic resin composition film at 25 ° C. and 30% RH to 85% RH is 100 ppm /% RH or less because dimensional change and characteristic change due to humidity change during processing or use are suppressed. . The humidity expansion coefficient of such an acrylic resin composition film is the acrylic resin composition after the acrylic resin composition film is set in a constant temperature and humidity chamber, dehumidified to a constant humidity (30% RH) and held for 24 hours. It can obtain | require by measuring the physical film length and the acrylic resin composition film length after leaving still for 24 hours in the state which raised humidity (85% RH). The initial acrylic resin composition film length at a temperature of 25 ° C. and a relative humidity of 65% is L0, and the acrylic resin composition film length after being allowed to stand for 24 hours at a humidified humidity M1 (= 85% RH) is L1, Let the acrylic resin composition film length in the humidity M2 (= 30% RH) after dehumidification be L2, and obtain | require a humidity expansion coefficient with the following formula | equation.
Humidity expansion coefficient (ppm /% RH) = {(L1-L2) / L0} / (M1-M2) × 10 ⁶ .

  In the present invention, the optical film is a film having an optical function, and specifically, a polarizing plate, a polarizing plate protective film, a retardation film, a light diffusion film, a viewing angle widening film, a reflective film, a reflective film used in a display or the like. Examples thereof include a protective film, an antiglare film, a brightness enhancement film, a conductive film for a touch panel, and protective films for various optical disc (VD, CD, DVD, MD, LD, etc.) substrates.

  Applications of the acrylic resin composition film of the present invention are not particularly limited. For example, in addition to the above optical film, camera, VTR, projection TV and other video equipment related parts such as filters, prisms, and Fresnel lenses, optical switches, optical It can be used for optical recording / optical communication related parts such as connectors, various covers, various terminal boards, printed wiring boards, speakers, microscopes, binoculars, cameras and watches. Among these, a polarizing plate, a polarizing plate protective film, a retardation film, a light diffusing film used in a display, etc., taking advantage of the characteristics of the acrylic resin composition film of the present invention that is excellent in transparency, defect-free property, and optical isotropy. Optical films such as protective films for viewing angle widening films, reflective films, antireflection films, antiglare films, brightness enhancement films, conductive films for touch panels, and various optical discs (VD, CD, DVD, MD, LD, etc.) If used, the effect is further utilized, which is more preferable.

  The present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto.

  The physical properties were measured and the effects were evaluated according to the following methods.

(1) Each component composition The acrylic resin composition film was dissolved in acetone, and this solution was centrifuged at 9000 rpm for 30 minutes to separate into an acetone soluble component and an acetone insoluble component. The acetone-soluble component was dried under reduced pressure at 60 ° C. for 5 hours, and each component unit was quantified to identify each component composition of the acrylic resin composition.

Quantification of each component unit was performed by a proton nuclear magnetic resonance ( ¹ H-NMR) method. ^{In the 1} H-NMR method, for example, in the case of a copolymer consisting of a glutaric anhydride unit, methacrylic acid, and methyl methacrylate, the spectral assignment in a dimethyl sulfoxide heavy solvent is 0.5 to 1.5 ppm peak. Is hydrogen of α-methyl group of methacrylic acid, methyl methacrylate and glutaric anhydride ring compound, peak of 1.6 to 2.1 ppm is hydrogen of methylene group of polymer main chain, peak of 3.5 ppm is methyl methacrylate The carboxylic acid ester (—COOCH ₃ ) of hydrogen, the peak at 12.4 ppm can determine the copolymer composition from the carboxylic acid hydrogen of methacrylic acid and the integral ratio of the spectrum. In addition to the above, in the case of a copolymer containing styrene as another copolymer component, hydrogen of the aromatic ring of styrene is seen at 6.5 to 7.5 ppm, and the copolymer composition is similarly determined from the spectral ratio. Can be determined.

In addition to the ¹ H-NMR method, each component unit can be quantified by infrared spectroscopy. In this method, glutaric anhydride units are characterized by absorption at 1800 cm ⁻¹ and 1760 cm ⁻¹ , and can be distinguished from units derived from vinyl carboxylic acids and units derived from vinyl carboxylic acid alkyl esters.

(2) Mass average molecular weight (absolute molecular weight)
Gel permeation chromatograph equipped with a DAWN-DSP type multi-angle light scattering photometer (manufactured by Wyatt Technology) using dimethylformamide as a solvent (pump: model 515, manufactured by Waters, column: TSK-gel-GMHXL, Tosoh Corporation) ).

(3) Glass transition temperature (Tg)
Using a differential scanning calorimeter (DSC-7 model, manufactured by Perkin Elmer), measurement was performed at a rate of temperature increase of 20 ° C./min under a nitrogen atmosphere, and the method for determining the midpoint glass transition temperature in 9.3 of JIS-K7121 Accordingly, the temperature is defined as the temperature at which the straight line equidistant in the vertical axis direction from the extended straight line of each base line of the measurement chart intersects with the curve of the step change portion of the glass transition.

(4) Residual solvent amount of acrylic resin composition coating film and acrylic resin composition film For data processing on thermal mass measuring device (TGA-50H) and analyzer thermal analyzer (TA-50) manufactured by Shimadzu Corporation The measurement was performed using an apparatus combined with a personal computer. About 7 mg of the acrylic resin composition coating film or acrylic resin composition film peeled from the support was set in a furnace, and the furnace was placed in a nitrogen atmosphere and heated from room temperature to 220 ° C. at a temperature rising rate of 10 ° C./min. . From the obtained thermal mass curve, the residual solvent amount of the acrylic resin composition coating film and the acrylic resin composition film was determined by the following formula. The measurement was performed twice per sample, and the average value was used as the residual solvent amount.

  Residual solvent amount (% by mass) = ((mass at 35 ° C.−mass at 200 ° C.) / Mass at 35 ° C.) × 100.

(5) Coating film peeling force A support is fixed using an automatic film strength measuring device AMF-50 manufactured by Orientec Co., Ltd., and the acrylic resin composition coating film is applied to the support plane under the following conditions. Was pulled in the direction of 180 °, and the stress at the time of peeling was obtained to obtain the coating film peeling force.

Sample size: width 25mm, length 150mm
Load cell: 100g
Tensile speed: 300 mm / min Measurement environment: 23 ° C., 65% RH, under atmospheric pressure When overshoot is observed at the initial stage of peeling or the peeling force changes midway, a stable load according to JIS-C6471 The average value of the part was defined as the peeling force. Even when there was no stable load portion, the minimum load was determined as the peeling force in accordance with JIS-C6471.

(6) Haze value and total light transmittance The haze value (%) and total light transmittance (%) at 23 ° C. were measured using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd.

(7) Tensile Young's modulus and elongation at break of acrylic resin composition film The film was measured under the following conditions using a film strength automatic elongation measuring apparatus “Tensilon AMF / RTA-100” manufactured by Orientec Co., Ltd.

Sample size: width 10mm, length 150mm
Chuck distance 50mm
Tensile speed: 300 mm / min Measurement environment: 23 ° C., 65% RH, under atmospheric pressure The tensile Young's modulus was determined from the tangent of the rising portion of the obtained load-elongation curve. Also, elongation obtained by multiplying the length obtained by subtracting the chuck distance from the length at the time of film break by the chuck distance was multiplied by 100.

(8) Moisture absorption rate of acrylic resin composition film About 0.5 g of acrylic resin composition film is sampled, heated for 3 hours at 105 ° C. for dehumidification, and then moisture absorption such as introduction of nitrogen gas for cooling. Then, the temperature was lowered to 25 ° C., and the mass of the acrylic resin composition film was measured (the mass at this time is defined as W0). Next, the acrylic resin composition film is allowed to stand in an atmosphere of 25 ° C. and a relative humidity of 75% for 48 hours, and the subsequent mass is measured (the mass at this time is W1). Asked.
Moisture absorption rate (%) = ((W1-W0) / W1) × 100.

(9) Thermal expansion coefficient of acrylic resin composition film Using a thermal / stress / strain measuring device TMA / SS6000 manufactured by Seiko Instruments Inc., the thermal expansion coefficient at 25 ° C. to 80 ° C. was measured under the following measurement conditions. .

Sample size: 15mm length, 4mm width
Temperature range: 25-150 ° C
Temperature increase rate: 5 ° C / min Temperature decrease rate: 5 ° C / min Load: 3g
Measurement environment: 65% RH, under atmospheric pressure The thermal expansion coefficient was measured in the temperature lowering process after the acrylic resin composition film was heated to 100 ° C. The initial acrylic resin composition film length L0 (= 15 mm) at a temperature of 25 ° C. and a relative humidity of 65%, the acrylic resin composition film length at a temperature of 80 ° C. is L1, and the acrylic resin composition film length at a temperature of 25 ° C. is L2 was obtained, and the thermal expansion coefficient was determined by the following equation.

Thermal expansion coefficient (ppm / ° C.) = (((L1-L2) / L0) / (80-25)) × 10 ⁶ .

(10) Humidity expansion coefficient of acrylic resin composition film A tape elongation test device manufactured by Okura Industry Co., Ltd. was installed in a constant temperature and humidity chamber, an acrylic resin composition film was set in this device, and a constant temperature, The amount of elongation of the acrylic resin composition film when the humidity was changed with a constant load was measured.

Sample size: Length 200mm, width 10mm
Temperature: 25 ° C
Humidity conditions: (Step 1) 30 ° C, 30% RH, hold for 24 hours
(Step 2) 30 ° C., 85% RH, maintained for 24 hours Humidification rate: 0.37% RH / minute (target humidity arrival time: 2 hours 30 minutes)
Load: 11.6g
The humidity expansion coefficient was determined by measuring the length of the acrylic resin composition film dehumidified in Step 1 (30 ° C., 30% RH, maintained for 24 hours) and then increasing the humidity at a rate of 0.37% RH / min. The acrylic resin composition film length after moisture absorption in Step 2 (30 ° C., 85% RH, held for 24 hours) was obtained by measurement. Initial acrylic resin composition film length L0 (= 200 mm) at a temperature of 25 ° C. and a relative humidity of 65%, the acrylic resin composition film length after standing for 24 hours at a humidity of 85% RH is L1, and the humidity is 30% RH. The humidity expansion coefficient was determined by the following equation, where L2 was the acrylic resin composition film length.

Humidity expansion coefficient (ppm /% RH) = (((L1-L2) / L0) / (85-30)) × 10 ⁶ .

(11) Phase difference at a wavelength of 550 nm Using an automatic birefringence meter (KOBRA-21ADH) manufactured by Oji Scientific Co., Ltd., in a chromatic dispersion measurement mode, a phase difference with respect to a light beam having a wavelength of 480.4 nm, a wavelength of 548.3 nm The phase difference with respect to the light beam, the phase difference with respect to the light beam with a wavelength of 628.2 nm, and the phase difference with respect to the light beam with a wavelength of 752.7 nm are measured, and the Cauchy wavelength dispersion formula (R (Λ) = a + b / λ ² + c / λ ⁴ + d / λ ⁶ ) coefficients a to d were obtained, and obtained by substituting the wavelength of 550 nm (λ = 550) into the Cauchy wavelength dispersion formula.

(12) Thickness direction retardation Rth
Using an automatic birefringence meter (KOBRA-21ADH) manufactured by Oji Scientific Co., Ltd., the refractive index in the direction of the orthogonal axis in the acrylic resin composition film surface with respect to light having a wavelength of 590 nm, nx, ny (however, nx ≧ ny), The refractive index nz in the thickness direction of the acrylic resin composition film with respect to light having a wavelength of 590 nm was measured, and the thickness was determined from the following formula when the thickness of the acrylic resin composition film was d (nm).
Thickness direction retardation Rth (nm) = d × {(nx + ny) / 2−nz}.

(13) Film defects The acrylic resin composition film peeled off from the support was visually checked for defects having a diameter of about 0.5 mm or more, and evaluated according to the following criteria.

○: Defects are not observed Δ: Defects are partially or entirely observed.

[Example 1]
(1) Preparation of acrylic resin composition First, a polyvinyl alcohol suspension (“Poval PVA-117” manufactured by Kuraray Co., Ltd.) 0.1 was added to a stainless steel autoclave equipped with a 20-liter baffle and a foudra-type stirring blade. A solution having mass% dissolved in 165% by mass of ion-exchanged water was supplied, and the system was bubbled with nitrogen gas at a flow rate of 10 liters / min for 15 minutes while stirring at 400 rpm. The dissolved oxygen concentration of the aqueous solution at this time was 2.5 ppm.

  Next, nitrogen gas was flowed at a flow rate of 5 liters / minute, the following mixed substances were added while stirring the reaction system, and the temperature was raised to 65 ° C.

Methacrylic acid: 30% by mass
Methyl methacrylate: 70% by mass
t-dodecyl mercaptan: 0.4% by mass
Lauryl peroxide: 0.3% by mass
Next, when the internal temperature reached 65 ° C., the polymerization start time was set, the internal temperature was maintained at 65 ° C. for 210 minutes, and then the temperature was increased to 85 ° C., and the internal temperature was maintained at 85 ° C. for 60 minutes to complete the polymerization.

  Thereafter, the reaction system was cooled, the polymer was separated, washed, and dried in accordance with ordinary methods to obtain bead-like acrylic resins and glutaric anhydride structural unit precursors. The polymerization rate of the acrylic resin and glutaric anhydride structural unit precursor was 98%, and the mass average molecular weight was 133,000.

  The acrylic resin and glutaric anhydride structural unit precursor obtained above were mixed with 100% by mass of lithium acetate as a catalyst, and 0.2% by mass of lithium acetate as a catalyst. Machine HTM38 (manufactured by CTE, L / D = 47.5, two vent portions). While purging nitrogen from the hopper at a flow rate of 10 liters / minute, an intramolecular cyclization reaction was performed at a screw rotation speed of 75 rpm, a raw material supply rate of 10 kg / h, and a cylinder temperature of 290 ° C. to obtain a pellet-shaped acrylic resin composition. .

  In this acrylic resin composition, the glutaric anhydride unit was 32% by mass, the methyl methacrylate unit was 65% by mass, and the methacrylic acid unit was 3% by mass. The glass transition temperature of the acrylic resin composition was 138 ° C.

(2) Preparation of acrylic elastic particles The following composition was added as an initial adjustment solution in a glass container (capacity 5 liters) with a cooler.

Deionized water: 120% by mass
Potassium carbonate: 0.5% by mass
Dioctyl sulfosuccinate: 0.5% by mass
Potassium persulfate: 0.005% by mass
While stirring the initial adjustment solution under a nitrogen atmosphere, the following composition was added and reacted at 70 ° C. for 30 minutes to obtain a rubbery polymer.

Butyl acrylate: 53% by mass
Styrene: 17% by mass
Allyl methacrylate (crosslinking agent): 1% by mass
The following composition was continuously added at 70 ° C. for 90 minutes while stirring, and after the addition was completed, the mixture was further maintained for 90 minutes to form a shell layer.

Methyl methacrylate: 21% by mass
Methacrylic acid: 9% by mass
Potassium persulfate: 0.005% by mass
The polymer latex was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to obtain core-shell type acrylic elastic particles. The average particle diameter of the rubbery polymer portion of the acrylic elastic particles measured with an electron microscope was 170 nm.

(3) Mixing of acrylic elastic particles 80 mass% of the acrylic resin composition obtained in the above (1) and 20 mass% of the core-shell type acrylic elastic particles obtained in the above (2) were biaxially extruded by Nippon Steel Corporation. Using a machine TEX30 (L / D = 44.5), while purging nitrogen from the hopper at a flow rate of 10 liters / minute, kneading at a screw speed of 100 rpm, a raw material supply rate of 5 kg / h, and a cylinder temperature of 280 ° C. A pellet-like particle-containing acrylic resin composition was obtained.

  The acrylic resin composition in which the acrylic elastic particles are mixed has a glutaric anhydride unit of 25.6% by mass, a methyl methacrylate unit of 52% by mass, a methacrylic acid unit of 2.4% by mass, and an acrylic elastic particle of 20%. It was mass%. The glass transition temperature of the acrylic resin composition mixed with acrylic elastic particles was 130 ° C.

(4) Preparation of acrylic resin composition solution The particle-containing acrylic resin composition obtained in (3) above was dried at 80 ° C for 8 hours using a vacuum dryer to remove moisture.

  Next, 25% by mass of the dried acrylic resin composition and 75% by mass of methyl ethyl ketone were added to a stainless steel reaction vessel equipped with a 200-liter recirculation system and a paddle type three-stage stirring blade, and the mixture was added at 80 rpm at 60 ° C. The mixture was stirred for a time to obtain an acrylic resin composition solution having an acrylic resin composition concentration of 25% by mass.

  Next, the acrylic resin composition solution was subjected to pressure filtration using a Y-strainer (manufactured by Washino Instruments) with a filtration accuracy of 50 μm and a depth type filter cartridge “Cuno Beta Pure” AU19Z11NG120 (manufactured by CUNO) made of polyolefin-based composite fiber with a filtration accuracy of 12 μm. .

  Further, the acrylic resin composition solution was subjected to pressure filtration with a sintered metal filter “Naslon Filter Media” NF2M-02S (manufactured by Nippon Seisen) having a filtration accuracy of 1.2 μm to obtain a final acrylic resin composition solution.

(5) Film formation of acrylic resin composition film The acrylic resin composition solution obtained in (4) above was coated on a support with a comma coater so that the coating thickness was 160 μm. The support uses a non-adhesive surface of polyethylene terephthalate film “Cosmo Shine” A4100 (manufactured by Toyobo Co., Ltd., film thickness 125 μm), and the acrylic resin composition coating film is dried using a tunnel nozzle of a slit nozzle hot air jet type. It was. In the present invention, the drying step of the acrylic resin composition coating film is based on a drying step consisting of an initial drying temperature T1 (° C), an intermediate drying temperature T2 (° C), and a final drying temperature T3 (° C). In the examples and comparative examples of the present invention, in order to further improve the defects and flatness of the acrylic resin composition film, the drying is performed at the drying temperatures of T1 (° C), T2 (° C), and T3 (° C). In addition to the steps, a drying step for further increasing the temperature was provided. Specifically, intermediate drying temperature T1 ′ (° C.) from initial drying to intermediate drying, second stage intermediate drying temperature T2 (2) (° C.), third stage intermediate drying temperature T2 (3) (° C.) A drying step having a drying temperature of the intermediate drying temperature T2 (4) (° C.) at the fourth stage and the final drying temperature T3 (2) (° C.) at the second stage was provided. The drying conditions for each drying step are shown below. The film forming conditions are shown in Table 1.

T1: 60 ° C (drying time 1 minute)
T1 ′: 70 ° C. (drying time 1 minute)
T2: 90 ° C. (drying time 1 minute)
T2 (2): 100 ° C. (drying time 1 minute)
T2 (3): 120 ° C. (drying time 1 minute)
T2 (4): 130 ° C. (drying time 1 minute)
T3: 150 ° C. (drying time 1 minute)
T3 (2): 150 ° C. (drying time 1 minute)
The acrylic resin composition coating film after drying (hereinafter abbreviated as primary dry coating film) was peeled from the support to obtain an acrylic resin composition film.

Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in In Examples 1 to 4 and Comparative Examples 1 to 8 of the present invention, since the acrylic resin composition coating film peeled from the support was not dried, the residual solvent amount of the acrylic resin composition coating film and the acrylic resin composition The residual solvent amount of the physical film is the same. [Example 2]
The primary dry coating film of Example 1 was re-dried again under the following conditions using an air floating oven. Here, in the examples and comparative examples of the present invention, the temperature when the drying apparatus was changed and the primary dry coating film was dried again was T4 (° C.). This drying process belongs to final drying. Table 1 shows the film forming conditions.

T4: 160 ° C. (drying time 8 minutes)
The acrylic resin composition coating film after drying was peeled from the support to obtain an acrylic resin composition film.

  Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in Moreover, the characteristic value of the said acrylic resin composition film is shown below.

Tensile Young's modulus: 2.7 GPa
Elongation at break: 24%
Moisture absorption: 1.1%
Thermal expansion coefficient: 81 ppm / ° C
Humidity expansion coefficient: 57ppm /% RH
[Example 3]
The primary dry coating film of Example 1 was re-dried again under the following conditions using an air floating oven. Table 1 shows the film forming conditions.

T4: 160 ° C. (drying time 10 minutes)
The acrylic resin composition coating film after drying was peeled from the support to obtain an acrylic resin composition film.

  Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

[Example 4]
The acrylic resin composition solution obtained in (4) of Example 1 was coated on a support with a comma coater so that the coating thickness was 320 μm. A non-adhesive surface of polyethylene terephthalate film “Cosmo Shine” A4100 (manufactured by Toyobo Co., Ltd., film thickness 125 μm) is used for the support, and the acrylic resin composition coating film is dried using a slit nozzle hot air jet type tunnel oven. It went on condition of.

T1: 65 ° C (drying time 1 minute 15 seconds)
T1 ′: 85 ° C. (drying time 1 minute 15 seconds)
T2: 110 ° C. (drying time 1 minute 15 seconds)
T2 (2): 130 ° C. (drying time 1 minute 15 seconds)
T3: 150 ° C. (drying time 1 minute 15 seconds)
The dried acrylic resin composition coating film was re-dried again under the following conditions using an air floating oven. The film forming conditions are shown in Table 1.

T4: 160 ° C. (drying time 8 minutes)
The acrylic resin composition coating film after drying was peeled from the support to obtain an acrylic resin composition film.

  Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in Moreover, the characteristic value of the said acrylic resin composition film is shown below.

Tensile Young's modulus: 2.5 GPa
Elongation at break: 26%
Moisture absorption: 1.1%
Thermal expansion coefficient: 87 ppm / ° C
Humidity expansion coefficient: 61 ppm /% RH
[Comparative Example 1]
An acrylic resin composition film was obtained in the same manner as in Example 2 except that the re-drying conditions in the air floating oven were as follows. Table 1 shows the film forming conditions.

T4: 160 ° C. (drying time 20 minutes)
Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

  Defects associated with peeling were found in the acrylic resin composition film.

[Comparative Example 2]
An acrylic resin composition film was obtained in the same manner as in Comparative Example 1 except that a release coating surface of a silicon release coating polyethylene terephthalate film “film binder” 0010GT (manufactured by Fujimori Kogyo Co., Ltd., film thickness: 100 μm) was used as a support. . Table 1 shows the film forming conditions.

  Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

  The coating film peeling force was low, and the acrylic resin composition coating film floated or peeled off during drying, resulting in deterioration of the flatness of the acrylic resin composition film.

[Comparative Example 3]
An acrylic resin composition film was obtained in the same manner as in Comparative Example 1 except that the re-drying conditions in the air floating oven were as follows. Table 1 shows the film forming conditions.

T4: 170 ° C. (drying time 20 minutes)
Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

  The coating film peeling force was high and peeling from the support was impossible.

[Comparative Example 4]
An acrylic resin composition film was obtained in the same manner as in Example 4 except that the re-drying conditions in the air floating oven were as follows. Table 1 shows the film forming conditions.

T4: 160 ° C. (drying time 20 minutes)
Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

  Defects associated with peeling were found in the acrylic resin composition film.

[Comparative Example 5]
An acrylic resin composition film was obtained in the same manner as in Example 4 except that the re-drying conditions in the air floating oven were as follows. Table 1 shows the film forming conditions.

T4: 160 ° C. (drying time 13 minutes 30 seconds)
Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

  Defects associated with peeling were found in the acrylic resin composition film.

[Comparative Example 6]
An acrylic resin composition film was obtained in the same manner as in Example 1 except that the drying conditions with a slit nozzle hot air jet type tunnel oven were as follows. Table 1 shows the film forming conditions.

T1: 60 ° C (drying time 1 minute)
T1 ′: 70 ° C. (drying time 1 minute)
T2: 90 ° C. (drying time 1 minute)
T2 (2): 100 ° C. (drying time 1 minute)
T2 (3): 120 ° C. (drying time 1 minute)
T2 (4): 130 ° C. (drying time 1 minute)
T3: 130 ° C. (drying time 1 minute)
T3 (2): 130 ° C. (drying time 1 minute)
Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

  Since the amount of residual solvent in the acrylic resin composition coating film was large, the winding property was deteriorated by blocking.

[Comparative Example 7]
An acrylic resin composition film was obtained in the same manner as in Comparative Example 3 except that the acrylic resin composition solution was applied on a support so as to have a coating thickness of 480 μm with a comma coater. Table 1 shows the film forming conditions.

  Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

  Since the amount of residual solvent in the acrylic resin composition coating film was large, the winding property was deteriorated by blocking. Moreover, the defect worsened to the acrylic resin composition film by foaming.

[Comparative Example 8]
An acrylic resin composition film was obtained in the same manner as in Comparative Example 1 except that the acrylic resin composition solution was applied to a support with a comma coater so as to have a coating thickness of 16 μm. Table 1 shows the film forming conditions.

  Table 2 shows the evaluation results of film thickness, residual solvent amount, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Shown in

  When the acrylic resin composition coating film was thin and peeled from the support, tearing occurred from the widthwise end of the acrylic resin composition film, and the peelability deteriorated.

[Comparative Example 9]
The 8th dry film of Example 1 was once peeled from the support, and the single-layer acrylic resin composition film was re-dried again under the following conditions using an air floating oven. Table 1 shows the film forming conditions.

T4: 120 ° C. (drying time 20 minutes)
Table 2 shows the evaluation results of film thickness, coating film peeling force, haze value, total light transmittance, retardation at a wavelength of 550 nm, retardation Rth in the thickness direction, and film defects of the acrylic resin composition film. Moreover, the residual solvent amount of the acrylic resin composition coating film in this comparative example and the residual solvent amount of the acrylic resin composition film are shown below.

Residual solvent amount of acrylic resin composition coating film: 1.8% by mass
Residual solvent amount of acrylic resin composition film: 1.7% by mass
The waved flatness of the acrylic resin composition film deteriorated due to heat shrinkage during re-drying.

The acrylic resin film obtained in the present invention is excellent in transparency, defect-free property, and optical isotropy, so that a polarizing plate, a polarizing plate protective film, a retardation film, a light diffusion film, and a viewing angle expansion used in displays and the like are used. Optical films such as films, reflective films, antireflection films, antiglare films, brightness enhancement films, conductive films for touch panels, protective films for various optical discs (VD, CD, DVD, MD, LD, etc.), cameras, VTRs, Viewfinders such as projection TV, parts related to video equipment such as filters, prisms, and Fresnel lenses, optical recording and optical communication related parts such as optical switches, optical connectors, various covers, various terminal boards, printed wiring boards, speakers, microscopes, binoculars Can be used for parts such as cameras and watches.
The use of the acrylic resin composition film of the present invention is not particularly limited.

Claims (7)

In the method of obtaining an acrylic resin composition film by coating an acrylic resin composition solution containing an acrylic resin composition and an organic solvent on a support, drying, and then peeling the support and the acrylic resin composition coating film. When the residual solvent amount in the resin composition coating film is 5% by mass or less, the support is fixed and the support and the acrylic resin composition coating film are peeled off, the 180 ° peeling force of the coating film on the support is 0. The manufacturing method of the acrylic resin composition film which is 0.5-5g / 25mm. When the acrylic resin composition is 100% by mass of the acrylic resin in the acrylic resin composition, a glutaric anhydride unit represented by the following structural formula (1), a lactone ring unit represented by the following structural formula (2), and the following structure The method for producing an acrylic resin composition film according to claim 1, which is an acrylic resin composition containing 20 to 40% by mass of at least one unit selected from maleimide units represented by formula (3).

(In the above formula ^(1), R 1, ^{R 2} represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)

(In said formula (2), R < ³ >, R < ⁴ >, R < ⁵ > represents a hydrogen atom or a C1-C20 alkyl group.)

(In the above formula (3), ^{R 6} represents an alkyl group, a cycloalkyl group or an aromatic group, of 1 to 18 carbon atoms.) The method for producing an acrylic resin composition film according to claim 1 or 2, wherein the glass transition temperature of the acrylic resin composition is 120 ° C or higher. The drying process of the acrylic resin composition coating applied on the support comprises at least three stages of initial drying, intermediate drying, and final drying. The boiling point of the organic solvent is bp (° C.), and the acrylic resin composition When the glass transition temperature is Tg (° C), the initial drying temperature is T1 (° C), the intermediate drying temperature is T2 (° C), and the final drying temperature is T3 (° C), the temperature in each drying step is represented by the following formula (I The method for producing an acrylic resin composition film according to any one of claims 1 to 3.
T1 (° C.) ≦ (bp−10) (° C.) (I)
(Tg-40) (° C.) ≦ T2 (° C.) ≦ Tg (° C.) (II)
Tg (° C.) <T3 (° C.) ≦ (Tg + 40) (° C.) (III) An acrylic resin composition film having an acrylic resin composition film having a haze value of 2% or less and a residual solvent amount of 5% by mass or less. The acrylic resin composition film according to claim 5, wherein the acrylic resin composition film has a thickness of 10 to 100 μm and a phase difference of 10 nm or less with respect to light having a wavelength of 550 nm. An optical film using the acrylic resin composition film according to claim 5.