JP7322002B2 - (Meth)acrylic resin composition, film and method for producing the same - Google Patents

Description

The present invention provides a (meth)acrylic resin composition capable of stably and easily forming a film excellent in optical properties, surface hardness, flex resistance, and impact resistance by long-term continuous operation, a film using the same, and its production. Regarding the method.

(Meth)acrylic resin compositions have characteristics such as high transparency, high surface hardness, excellent weather resistance, and easy molding. It is used in various applications such as interior and exterior materials for vehicles, interior and exterior materials for building materials, and interior members. In particular, it is used as a skin material for various members because of its excellent surface properties such as high pencil hardness. In addition, because of its excellent transparency and low birefringence, it is used as various optical members such as polarizer protective films, retardation films, and scattering prevention films. However, not limited to acrylic resins, when thermoplastic resins are formed by melt extrusion, there is a problem that a gel-like deterioration product is generated in the stagnant part and it becomes a fish-eye defect, and there is little fish-eye. There are still problems to be solved in long-term continuous operation for long-term stable production of film.

As a method for long-term continuous operation, there is a method of forming a film at a low temperature. A method of reducing stagnant points is generally used, but the present situation is that stagnant points remain (Patent Document 1). In addition, an aliphatic alcohol is known as a lubricant for (meth)acrylic resin. It is known that it is possible to suppress fusion to a tool even in cutting work, and that productivity is improved because it is unnecessary to add a lubricant (Patent Document 2).

JP 2017-170620 A WO2014/156032

However, the method described in Patent Document 2 has room for further improvement in order to enable stable production of the film itself by long-term continuous operation.
In addition, as described above, further improvement is required for long-term continuous operation, especially in the case of a (meth)acrylic resin film with excellent impact resistance to which a rubber component is added, fish eyes are likely to occur. Long-term continuous operation was more difficult. That is, in order to stably and easily obtain a film containing a rubber component and having excellent impact resistance, having low haze, excellent optical properties, high surface hardness, and excellent flex resistance, by long-term continuous operation. There is still room for study from the viewpoint of cost reduction.

The present invention has been made in view of the above background. An object of the present invention is to provide a (meth)acrylic resin composition that can be formed into a film, a film using the same, and a method for producing the same.

As a result of extensive studies to achieve the above object, the present inventors have found that (meth)acrylic resin (A) and core-shell type graft copolymer (B) are used in combination, and aliphatic alcohol (C) is specified. According to the (meth)acrylic resin composition obtained by blending a large amount, it is possible to provide a film having low haze, good optical properties, high surface hardness, excellent bending resistance, and excellent impact resistance. The (meth)acrylic resin composition has excellent long-term stability when melted, produces less fisheyes when formed into a film, and stably and easily forms the film by long-term continuous operation. The present inventors have found that it is possible to achieve this, and have completed the present invention through further studies based on this finding.

That is, the present invention relates to the following.
[1] A (meth)acrylic resin containing a total of 100 parts by mass of a (meth)acrylic resin (A) and a core-shell type graft copolymer (B) and 0.03 to 0.3 parts by mass of an aliphatic alcohol (C) Resin composition.
[2] The (meth)acrylic resin composition according to [1], which has a melt viscosity of 2,000 Pa·s or less at 270°C and a shear rate of 12.2/sec.
[3] The (meth)acrylic resin composition according to [1] or [2], wherein the (meth)acrylic resin (A) contains at least two types of (meth)acrylic resins having different weight average molecular weights.
[4] Any one of [1] to [3], wherein the (meth)acrylic resin (A) and the core-shell type graft copolymer (B) have a mass ratio of the former/latter = 70/30 to 90/10. or the (meth)acrylic resin composition according to any one of the above.
[5] The (meth)acrylic resin composition according to any one of [1] to [4], wherein the aliphatic alcohol (C) is stearyl alcohol.
[6] The (meth)acrylic resin composition according to any one of [1] to [5], further comprising 0.1 to 3% by mass of a polymer processing aid (D).
[7] A film made of the (meth)acrylic resin composition according to any one of [1] to [6].
[8] The film of [7], which has a pencil hardness of HB or higher.
[9] The film according to [7] or [8], which has a folding endurance of 30 times or more.
[10] A decorative film made of the film according to any one of [7] to [9].
[11] An optical film comprising the film according to any one of [7] to [9].
[12] A polarizer protective film comprising the film according to any one of [7] to [9].
[13] A polarizing plate comprising the polarizer protective film of [12].
[14] The method for producing the film according to any one of [7] to [9], wherein an extrusion device equipped with a vent, a gear pump, a polymer filter and a T die in this order is used, and from the vent to the T die A method for producing a film, wherein the temperature of is controlled at 230 to 290 ° C.

According to the present invention, a film having low haze, good optical properties, high surface hardness, excellent flex resistance, and excellent impact resistance can be stably and easily formed by long-term continuous operation (meta). An acrylic resin composition, a film using the same, and a method for producing the same are provided.

The (meth)acrylic resin composition of the present invention contains a total of 100 parts by mass of the (meth)acrylic resin (A) and the core-shell type graft copolymer (B), and 0.03 to 0.03 parts by mass of the aliphatic alcohol (C). Contains 3 parts by mass.

<(Meth) acrylic resin (A)>
As the (meth)acrylic resin (A) used in the present invention, for example, one mainly composed of structural units derived from methyl methacrylate can be used. The content of the structural unit (methyl methacrylate unit) derived from methyl methacrylate in the (meth)acrylic resin (A) is preferably 50% by mass or more, and 80% by mass or more, from the viewpoint of heat resistance. more preferably 90% by mass or more, particularly preferably 95% by mass or more, and all structural units may be methyl methacrylate units.

The (meth)acrylic resin (A) may contain structural units derived from monomers other than methyl methacrylate. Such other monomers are not particularly limited as long as they are copolymerizable with methyl methacrylate. Examples include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, and n-butyl acrylate. , isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, acrylic acid Acrylic acids such as phenyl, benzyl acrylate, phenoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-ethoxyethyl acrylate, glycidyl acrylate, allyl acrylate, cyclohexyl acrylate, norbornyl acrylate, and isobornyl acrylate Ester; ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, n-methacrylate hexyl, 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate, 2-ethoxyethyl methacrylate, glycidyl methacrylate, Methacrylic acid esters other than methyl methacrylate such as allyl methacrylate, cyclohexyl methacrylate, norbornyl methacrylate and isobornyl methacrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, maleic acid and itaconic acid; or its acid anhydrides; olefins such as ethylene, propylene, 1-butene, isobutylene and 1-octene; conjugated dienes such as butadiene, isoprene and myrcene; styrene, α-methylstyrene, p-methylstyrene and m-methylstyrene Aromatic vinyl compounds; acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, vinyl acetate, vinylpyridine, vinyl ketone, vinyl chloride, vinylidene chloride, vinylidene fluoride and the like.

The stereoregularity of the (meth)acrylic resin (A) is not particularly limited, and for example, isotactic, heterotactic, syndiotactic (meth)acrylic resins (A) having stereoregularity can be used.

The (meth)acrylic resin composition of the present invention may contain only one type of (meth)acrylic resin as the (meth)acrylic resin (A), but the effects of the present invention can be exhibited more remarkably. For these reasons, it preferably contains two or more (meth)acrylic resins, and particularly preferably contains at least two (meth)acrylic resins (A-1 and A-2) having different weight average molecular weights.

The (meth)acrylic resin (A-1) is preferably a resin having a high content of methyl methacrylate units and a high weight average molecular weight (Mw) in order to improve heat resistance. The content of methyl methacrylate units in the (meth)acrylic resin (A-1) is preferably 95% by mass or more, more preferably 97% by mass or more, and still more preferably 99% by mass or more. The (meth)acrylic resin (A-1) preferably has a weight average molecular weight of 80,000 to 150,000, more preferably 85,000 to 120,000, still more preferably 90,000 to 100, 000. When the weight average molecular weight of the (meth)acrylic resin (A-1) is 80,000 or more, the mechanical properties are good, and when the weight average molecular weight of the (meth)acrylic resin (A-1) is 150,000 or less. It is possible to prevent the melt viscosity from becoming too high, and the processability is improved.

The (meth)acrylic resin (A-2) is mainly a compatibilizer for enhancing the dispersibility of the core-shell graft copolymer (B) in the (meth)acrylic resin composition of the present invention. For example, in the case of the above purpose, the content of the methyl methacrylate unit in the (meth)acrylic resin (A-2) is the above-described (meth)acrylic The ratio between the content of methyl methacrylate units in resin (A-1) and the content of methyl methacrylate units in thermoplastic polymer (II) constituting the outermost layer of core-shell graft copolymer (B) described later. It is preferably between (including the same case). Further, the weight average molecular weight of the (meth)acrylic resin (A-2) is preferably lower than the weight average molecular weight of the (meth)acrylic resin (A-1). The (meth)acrylic resin (A-2) preferably has a weight average molecular weight of 30,000 to 80,000, more preferably 40,000 to 75,000, still more preferably 50,000 to 70,000. When the weight molecular weight of the (meth) acrylic resin (A-2) is 30,000 or more, the mechanical properties are good, and when the weight average molecular weight of the (meth) acrylic resin (A-2) is 80,000 or less, the It can fully play a role like a solubilizer.

The molecular weight distribution of the (meth)acrylic resin (A) is represented by the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) when measured by GPC, and is 1.05 to 3. is preferred, and 1.3 to 2.5 is more preferred. When the molecular weight distribution is 1.05 or more, molding becomes easy, and when the molecular weight distribution is 3 or less, physical properties such as creep properties are improved.
The weight average molecular weight (Mw) can be measured by the method described later in Examples, and the number average molecular weight (Mn) can also be measured in the same manner.

The method for producing the (meth)acrylic resin (A) is not particularly limited, and it can be obtained, for example, by polymerizing monomers mainly composed of methyl methacrylate. The degree of polymerization of the (meth)acrylic resin (A) can be adjusted by adjusting the amounts of the polymerization initiator and the chain transfer agent.

Moreover, you may use a commercial item as a (meth)acrylic resin (A). Examples of such methacrylic resins include "PARAPET H1000B" (MFR: 22 g/10 minutes (230°C, 37.3N)), "PARAPET GF" (MFR: 15 g/10 minutes (230°C, 37.3N)), " Parapet EH" (MFR: 1.3 g/10 min (230°C, 37.3 N)), "Parapet HRL" (MFR: 2.0 g/10 min (230°C, 37.3 N)), "Parapet HRS" ( MFR: 2.4 g / 10 minutes (230 ° C., 37.3 N)) and "Parapet G" (MFR: 8.0 g / 10 minutes (230 ° C., 37.3 N)) [both trade names, manufactured by Kuraray Co., Ltd. ] and the like.

The glass transition temperature (Tg) of the (meth)acrylic resin (A) is preferably 80 to 140°C, more preferably 95 to 130°C, still more preferably 110 to 120°C. The glass transition temperature can be adjusted by changing the stereoregularity by changing the type and amount of monomers to be copolymerized with methyl methacrylate, the polymerization temperature, and the like. The glass transition temperature is a value measured according to JIS K7121:2012. That is, the (meth)acrylic resin (A) is once heated to 200°C, then cooled to room temperature (25°C), and then differential scanning calorimetry is performed under the conditions of raising the temperature from room temperature to 200°C at a rate of 10°C/min. A DSC curve is measured by a measurement method, and the midpoint glass transition temperature obtained from the DSC curve measured during the second heating can be taken as the glass transition temperature of the (meth)acrylic resin (A).

<Core-shell type graft copolymer (B)>
Crosslinked rubber particles having an outermost layer and an inner layer can be used as the core-shell type graft copolymer (B) used in the (meth)acrylic resin composition of the present invention. The type of such crosslinked rubber particles is not particularly limited as long as it has an outermost layer and an inner layer. For example, the core (inner layer) is a crosslinked rubber polymer (I) and the outer shell (outermost layer) is a thermoplastic polymer. Two-layer polymer particles of (II); core (inner layer) of polymer (III) - inner shell (inner layer) of crosslinked rubber polymer (I) - outer shell (outermost layer) of thermoplastic polymer (II) Three-layer polymer particles: core (inner layer) is crosslinked rubber polymer (I) - first inner shell (inner layer) is polymer (III) - second inner shell (inner layer) is crosslinked rubber polymer (I) - outer Although various layered structures are possible, such as four-layer polymer particles in which the shell (outermost layer) is thermoplastic polymer (II), three-layer polymer particles are preferred.

The crosslinked rubber polymer (I) contains 70 to 98 structural units derived from an acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms, relative to the weight of the crosslinked rubber polymer (I). % by mass, preferably 75 to 90% by mass, even more preferably 80 to 85% by mass. With the above content, it becomes a flexible rubber material and can impart impact resistance. Further, the crosslinked rubber polymer (I) preferably contains 2 to 30% by mass, more preferably 10 to 25% by mass, of the structural unit derived from the aromatic vinyl monomer relative to the mass of the crosslinked rubber polymer (I). More preferably, it contains 15 to 20% by mass. With the above content, the refractive index of the crosslinked rubber polymer (I) can be adjusted to match that of the (meth)acrylic resin (A), and a (meth)acrylic resin composition having high transparency can be obtained. can.
Further, the crosslinked rubber polymer (I) preferably contains 1 to 5% by mass, more preferably 1 to 3% by mass, of a structural unit derived from a crosslinkable monomer with respect to the mass of the crosslinked rubber polymer (I). It is more preferable to include With the above content, a moderate cross-linking density is obtained, and the behavior as a rubber material is improved.

The thermoplastic polymer (II) preferably contains 80 to 100% by mass of methyl methacrylate units, more preferably 85 to 97% by mass, based on the mass of the thermoplastic polymer (II). It is more preferable to contain 96% by mass. The above content improves compatibility with the (meth)acrylic resin (A).
Further, the thermoplastic polymer (II) has 0 structural units derived from an acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms, relative to the mass of the thermoplastic polymer (II). It preferably contains up to 20% by mass, more preferably 3 to 15% by mass, and even more preferably 4 to 10% by mass. The above content improves compatibility with the (meth)acrylic resin (A).

Polymer (III) preferably contains 80 to 99.95% by mass of methyl methacrylate units, more preferably 85 to 98% by mass, relative to the mass of polymer (III), and 90 to 96% by mass. % is more preferable. The above content is preferable because the hardness is improved.
The polymer (III) contains 0 to 19.95% by mass of a structural unit derived from an acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms, relative to the mass of the polymer (III). , and preferably 0.05 to 2% by mass of a crosslinkable monomer, and 2 to 15% by mass of a structural unit derived from an acrylic alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms. , and more preferably contains 0.05 to 1.5% by mass of structural units derived from a crosslinkable monomer, and the alkyl group is derived from an acrylic acid alkyl ester monomer having 1 to 8 carbon atoms. It is more preferable to contain 4 to 10% by mass of structural units that are derived from crosslinkable monomers and 0.1 to 1% by mass of structural units derived from crosslinkable monomers. The above content is preferable because the hardness is improved.

The content of each monomer above is calculated for each layer. For example, in a four-layer polymer particle, when both the core (inner layer) and the second inner shell (inner layer) are composed of the crosslinked rubber polymer (I), the content of structural units derived from each monomer is The core (inner layer) and the second inner shell (inner layer) are calculated separately.

From the viewpoint of transparency of the core-shell graft copolymer (B), the difference in refractive index between adjacent layers is preferably less than 0.005, more preferably less than 0.004, and even more preferably less than 0.003. It is preferable to select the polymer contained in each layer so that

The mass ratio of the inner layer to the outermost layer in the core-shell graft copolymer (B) is preferably former/latter=30/70 to 95/5, more preferably 70/30 to 90/10. In this specification, the outermost layer of the core-shell graft copolymer (B) refers to the outermost layer of the particle, and the inner layer refers to all the layers inside the outermost layer. The ratio of the layer containing the crosslinked rubber polymer (I) in the inner layer is preferably 20 to 70% by mass, more preferably 30 to 50% by mass.

The average particle size of the core-shell type graft copolymer (B) in the present invention is preferably 0.05 to 1 μm, more preferably 0.07 to 0.5 μm, still more preferably 0.1 to 0.5 μm. 4 μm, particularly preferably 0.15 to 0.3 μm. When the core-shell type graft copolymer (B) having an average particle size within such a range is used, toughness can be expressed with a small amount of blending, and the possibility of impairing rigidity and surface hardness can be suppressed. . The average particle size in the present specification is the arithmetic mean value in the volume-based particle size distribution measured by a light scattering method, and can be specifically determined by the method described in Examples.

The method for producing the core-shell type graft copolymer (B) is not particularly limited, and a known method can be used, but an emulsion polymerization method is preferred. Specifically, the monomers constituting the core (inner layer) are emulsion-polymerized to obtain seed particles, and the monomers constituting each layer are sequentially added in the presence of the seed particles to sequentially form the outermost layer. It can be obtained by carrying out polymerization.

Examples of emulsifiers used in the emulsion polymerization method include anionic emulsifiers such as dialkylsulfosuccinates such as sodium dioctylsulfosuccinate and sodium dilaurylsulfosuccinate, alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate. Alkyl sulfates of; Nonionic emulsifiers such as polyoxyethylene alkyl ether and polyoxyethylene nonylphenyl ether; Nonionic and anionic emulsifiers such as polyoxyethylene nonylphenyl ether sulfates such as sodium polyoxyethylene nonylphenyl ether sulfate polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene alkyl ether sulfate; alkyl ether carboxylates such as polyoxyethylene tridecyl ether sodium acetate; These may be used singly or in combination of two or more. The average number of repeating units of ethylene oxide units in exemplary compounds of nonionic emulsifiers and nonionic/anionic emulsifiers is preferably 30 or less, more preferably 30 or less, in order to prevent the foamability of the emulsifier from becoming extremely large. It is 20 or less, more preferably 10 or less.

The polymerization initiator used for emulsion polymerization is not particularly limited, and examples thereof include persulfate-based initiators such as potassium persulfate and ammonium persulfate; A system initiator or the like can be used.

Separation and acquisition of the core-shell type graft copolymer from the polymer latex obtained by emulsion polymerization can be carried out by known methods such as salting-out coagulation, freeze-coagulation and spray drying. Among these, the salting-out coagulation method and the freeze-coagulation method are preferable, and the freeze-coagulation method is more preferable, because impurities contained in the crosslinked rubber particle component can be easily removed by washing with water. Since the freeze-coagulation method does not use a flocculating agent, it is easy to obtain a film with excellent water resistance. In order to remove foreign substances mixed in the polymer latex before the coagulation step, it is preferable to filter the polymer latex through a wire mesh having an opening of 50 μm or less. From the viewpoint of facilitating uniform dispersion in melt-kneading with the (meth)acrylic resin (A), the core-shell graft copolymer (B) is preferably taken out as aggregated particles of 1,000 μm or less, and aggregated particles of 500 μm or less. It is more preferable to take out as The form of the agglomerated particles is not particularly limited. For example, the particles may be in the form of pellets fused together at the outermost layer, or may be in the form of powder or granules.

The content of the core-shell graft copolymer (B) in the (meth)acrylic resin composition of the present invention is not particularly limited, but the mass ratio of the (meth)acrylic resin (A) to the core-shell graft copolymer (B) is However, the former/latter is preferably 70/30 to 90/10, more preferably 75/25 to 85/15, still more preferably 77/23 to 83/17. When the mass ratio is within this range, a (meth)acrylic resin composition having an excellent balance between hardness and impact resistance can be obtained.

<Aliphatic alcohol (C)>
The (meth)acrylic resin composition of the present invention contains 0.03 of the aliphatic alcohol (C) per 100 parts by mass of the total amount of the (meth)acrylic resin (A) and the core-shell type graft copolymer (B). Contains up to 0.3 parts by mass. The content of the aliphatic alcohol (C) is preferably 0.03 to 0.2 parts by mass with respect to 100 parts by mass of the total amount of the (meth)acrylic resin (A) and the core-shell type graft copolymer (B). and more preferably 0.04 to 0.09 parts by mass. If the content of the aliphatic alcohol (C) is less than 0.03 parts by mass, the long-term stability during melting will be insufficient, and if the content of the aliphatic alcohol (C) exceeds 0.3 parts by mass, Poor long-term stability.

The type of the fatty alcohol (C) is not particularly limited, but preferred are fatty alcohols having 12 to 18 carbon atoms such as lauryl alcohol, palmityl alcohol, stearyl alcohol and oleyl alcohol, and lauryl alcohol, palmityl alcohol and stearyl alcohol. More preferred are saturated aliphatic alcohols having 12 to 18 carbon atoms such as , more preferred are saturated fatty alcohols having 16 to 18 carbon atoms such as palmityl alcohol and stearyl alcohol, and particularly preferred is stearyl alcohol. Aliphatic alcohol (C) may be used individually by 1 type, or may use 2 or more types together.

<Other additives>
In the (meth)acrylic resin composition of the present invention, various additives, such as a polymer processing aid (D), an ultraviolet absorber (E), Antioxidants, heat stabilizers, lubricants, antistatic agents, colorants, impact resistance aids, etc., the above (meth)acrylic resin (A), core-shell type graft copolymer (B) and aliphatic alcohol (C) Other additives may be added. From the viewpoint of the mechanical properties and surface hardness of the film of the present invention, it is preferable not to add a large amount of foaming agents, fillers, matting agents, light diffusing agents, softening agents, and plasticizers.

<Polymer Processing Aid (D)>
The (meth)acrylic resin composition of the present invention preferably further contains a polymer processing aid (D) as the other additive described above. The polymer processing aid (D) is a compound that exhibits effects such as thickness accuracy, film forming stability and reduction of fish eyes when molding the resin composition of the present invention. As the polymer processing aid (D), an ultra-high molecular weight (weight average molecular weight of 500,000 or more) mainly composed of methyl methacrylate units (for example, containing 50% by mass or more) can be usually produced by an emulsion polymerization method. methacrylic resin, preferably polymer particles having a particle size of 0.05 to 0.5 μm.

Commercially available products can be used as the polymer processing aid (D). Specifically, "Kane Ace" PA series (manufactured by Kaneka Corporation), "Metabrene" P series (manufactured by Mitsubishi Rayon Co., Ltd.), "Paraloid" K series (manufactured by Dow). Among them, "Paraloid" K125P is preferable from the viewpoint of compatibility with the resin.

The content of the polymer processing aid (D) in the (meth)acrylic resin composition of the present invention is preferably 0.1 to 3% by mass. The content of the polymer processing aid (D) varies depending on the application, but from the viewpoint of further reducing fish eyes, it is more preferably 1.0% by mass or more, and 1.3% by mass or more. is more preferred. Moreover, from the viewpoints of suppressing costs and suppressing melt viscosity, the content is more preferably 2.5% by mass or less, and even more preferably 2.0% by mass or less.

<Ultraviolet absorber (E)>
The (meth)acrylic resin composition of the present invention preferably further contains an ultraviolet absorber (E) as the other additive described above. The ultraviolet absorber (E) is a compound capable of absorbing ultraviolet rays, and mainly has the function of converting light energy into heat energy.

Examples of the ultraviolet absorber (E) include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, formamidines and the like. These may be used individually by 1 type, or may use 2 or more types together. Among these, benzotriazoles and triazines are preferable because they have a high ability to suppress deterioration of the resin when irradiated with ultraviolet rays and have a high compatibility with the resin.

Benzotriazole-based UV absorbers are highly effective in suppressing degradation of optical properties such as coloration due to UV irradiation. Examples of benzotriazole UV absorbers include 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol ("TINUVIN" 329 manufactured by BASF), 2 -(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (BASF "tinuvin" 234) and 2,2'-methylenebis[6-( 2H-benzotriazol-2-yl)-4-tert-octylphenol] (“ADEKA STAB” LA-31 manufactured by ADEKA) and the like, and from the viewpoint of compatibility with the (meth)acrylic resin composition of the present invention, ,2′-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] (“ADEKA STAB” LA-31, manufactured by ADEKA) is preferred.

Examples of triazine UV absorbers include hydroxyphenyltriazine UV absorbers, and more specifically, 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-( 2,4-butyloxyphenyl)-1,3,5-triazine (BASF "tinuvin" 460), 2-(4-(2-hydroxy-3-(2-ethylhexyloxy)propyloxy)-2- Hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine ("TINUVIN" 405 manufactured by BASF), 2-(2-hydroxy-4-[1-octyloxycarbonyl ethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (BASF "tinuvin" 479), BASF "tinuvin" 1477, 400, 477, 1600; (4,6-diphenyl-1,3,5-triazin-2-yl)-5-(2-(2-ethylhexanoyloxy)ethoxy)phenol ("ADEKA STAB" LA-46 manufactured by ADEKA), 2, 4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenoxy)-1,3,5-triazine (adeka "adekastab" LA-F70); 2-[4-[(2-hydroxy -3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3 -tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and the like.

The content of the ultraviolet absorber (E) in the (meth)acrylic resin composition of the present invention is preferably 0.1 to 3% by mass. The content of the ultraviolet absorber (E) varies depending on the type and application of the ultraviolet absorber (E), but is more preferably 0.2% by mass or more, and is 0.4% by mass or more. is more preferred. Moreover, from the viewpoint of suppressing costs, it is more preferably 2.8% by mass or less, and even more preferably 2.5% by mass or less.

<Other polymers>
The (meth)acrylic resin composition of the present invention comprises a (meth)acrylic resin (A), a core-shell type graft copolymer (B), and a polymer processing aid that may be a polymer within a range that does not impair the effects of the present invention. A polymer other than the agent (D) can be further included. Such other polymers include polyolefin resins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, and polynorbornene; ethylene-based ionomers; polystyrene, styrene-maleic anhydride copolymers, and high-impact polystyrene. , AS resin, ABS resin, AES resin, AAS resin, ACS resin, MBS resin and other styrene resins; methyl methacrylate-styrene copolymer; polyethylene terephthalate, polybutylene terephthalate and other polyester resins; nylon 6, nylon 66, polyamide Polyamide such as elastomer; Polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacetal, polyvinylidene fluoride, polyurethane, modified polyphenylene ether, polyphenylene sulfide, modified silicone resin; acrylic rubber, silicone rubber styrene thermoplastic elastomers such as SEPS, SEBS and SIS; and olefin rubbers such as IR, EPR and EPDM.

<(Meth) acrylic resin composition>
The (meth)acrylic resin composition of the present invention preferably has a melt viscosity of 2,000 Pa·s or less at 270° C. and a shear rate of 12.2/sec. From the viewpoint that film formation can be easily performed at a low temperature, the melt viscosity at a shear rate of 12.2 / sec at 270 ° C. is more preferably 1,800 Pa s or less, still more preferably 1,500 Pa s or less, especially It is preferably 1,200 Pa·s or less. When the melt viscosity is 2,000 Pa·s or less, the film-forming temperature does not become too high, and stable long-term continuous operation becomes possible. The lower limit of melt viscosity is preferably 300 Pa·s, more preferably 500 Pa·s from the viewpoint of mechanical properties. The melt viscosity is determined by the weight average molecular weight of the (meth)acrylic resin (A), the mass ratio between the (meth)acrylic resin (A) and the core-shell graft copolymer (B), and the content of other additives. can be adjusted. The melt viscosity can be measured by the method described in Examples.

The method of preparing the (meth)acrylic resin composition of the present invention is not particularly limited, but a method of melt-kneading and mixing is preferred. Specifically, (meth)acrylic resin (A), core-shell type graft copolymer (B) and aliphatic alcohol (C), and if necessary further polymer processing aid (D), ultraviolet absorber ( A method of preliminarily dry-blending other additives such as E) and other polymers and melt-kneading is generally used. The mixing operation can be carried out, for example, using known mixing or kneading equipment such as kneader ruders, extruders, mixing rolls, Banbury mixers and the like. In particular, from the viewpoint of kneadability and productivity, it is preferable to use a twin-screw extruder. The shear rate during melt-kneading is preferably 10 to 1,000/sec. The temperature during mixing and kneading is generally 150 to 320°C, preferably 200 to 300°C. When melt-kneading is performed using a twin-screw extruder, it is preferable to use a vent and perform melt-kneading under reduced pressure or under a nitrogen stream from the viewpoint of suppressing coloring. Thus, the (meth)acrylic resin composition of the present invention can be obtained, for example, in the form of pellets.

The lower limit of the total content of the (meth)acrylic resin (A) and the core-shell type graft copolymer (B) in the (meth)acrylic resin composition of the present invention is usually 50% by mass, preferably 70% by mass. %, more preferably 80% by mass, and still more preferably 85% by mass. Also, the upper limit is preferably 99.97% by mass, more preferably 99.96% by mass, still more preferably 99.95% by mass.

<Film>
The (meth)acrylic resin composition of the present invention can be molded into a film. The film can be produced by a known method such as a T-die method, an inflation method, a melt casting method, a calender method, and the like. From the viewpoint of obtaining a film with good surface smoothness and low haze, the (meth)acrylic resin composition of the present invention is melt-kneaded and extruded in a molten state from a T-die, and both surfaces thereof are coated on mirror roll surfaces or mirror belt surfaces. Preferably, the step of contact molding is included. Any of the rolls or belts used at this time is preferably made of metal. When both sides of the extruded melt-kneaded product are brought into contact with a mirror surface to form a film, the melt-kneaded product (which may be a film) is preferably pressed and sandwiched between mirror-surface rolls or a mirror-surface belt. The pinching pressure by the mirror-finished rolls or the mirror-finished belt is preferably higher, and the linear pressure is preferably 10 N/mm or more, more preferably 20 N/mm or more. The surface temperature of the sandwiched mirror-finished rolls or mirror-finished belts is preferably 60° C. or higher, more preferably 70° C. or higher. Also, it is preferably 130° C. or lower, more preferably 100° C. or lower. When the surface temperature of the mirror surface roll or mirror surface belt sandwiching the melt-kneaded material is 60°C or higher, the surface smoothness and haze of the resulting film are improved. Excessive adhesion of the belt can be suppressed, surface roughness and lateral wrinkles are less likely to occur when the film is peeled off from the mirror-finished roll or the mirror-finished belt, and the appearance of the film can be improved.

In the case of the production method by the T-die method, an extruder-type melt extruder with a single or twin screw can be used. The melt extrusion temperature for producing the film of the present invention is preferably 230°C or higher, more preferably 240°C or higher. The melt extrusion temperature is preferably 290° C. or lower, more preferably 280° C. or lower. In addition, when using a melt extrusion device, from the viewpoint of suppressing coloring, melt extrusion is performed under reduced pressure using a vent, and a gear pump is attached from the viewpoint of producing a film with a uniform thickness, and furthermore, in order to reduce fisheye defects. Melt extrusion with a polymer filter is preferred. Furthermore, from the viewpoint of suppressing oxidative deterioration, it is preferable to carry out melt extrusion under a nitrogen stream.

When a film made of the (meth)acrylic resin composition of the present invention is produced by an extrusion device equipped with a vent, a gear pump, a polymer filter and a T-die in this order, from the vent to the T-die including the gear pump and the polymer filter It is preferable to control the temperature in the range of 230-290°C. By manufacturing in such a temperature range, it is possible to obtain a film that is less deteriorated, has less fish eyes, and has excellent mechanical properties and optical properties.

The haze of the film made of the (meth)acrylic resin composition of the present invention is preferably 1.5% or less at a thickness of 75 μm, more preferably 1.2% or less, and 1.0% or less. It is even more preferable to have Within the above range, the surface gloss and the sharpness of the pattern layer printed on the film of the present invention are more excellent when used in applications requiring designability. Moreover, in optical applications such as a polarizer protective film and a light guide film, it is preferable because the utilization efficiency of the light source increases. Furthermore, it is preferable because it is excellent in shaping accuracy when performing surface shaping. The haze can be determined by the method described in Examples.

The pencil hardness of the film made of the (meth)acrylic resin composition of the present invention is preferably HB or higher, more preferably F or higher, and still more preferably H or higher. If the pencil hardness is high, the surface of the film is less likely to be damaged, so it is suitable as a decoration and surface protection film for the surface of molded products that require design.It is also suitable for use as a protective film for polarizers in product manufacturing processes such as lamination. It is preferable because it can suppress the occurrence of scratches occurring inside. The pencil hardness can be determined by the method described in Examples.

The number of folds indicating the bending resistance of the film made of the (meth)acrylic resin composition of the present invention is preferably 30 times or more, more preferably 40 times or more, and still more preferably 50 times or more. When the folding endurance is measured in both the MD direction and the TD direction of the film, the lower one of these is preferably within the above range. As a result, even when used as a decorative film, a polarizer protective film, or the like, cracking can be suppressed when receiving an impact, processing, or handling of the final product, which is preferable. The number of folding endurances can be measured in accordance with JIS P8115:2001 as the number of reciprocating foldings until the test piece breaks. Specifically, it can be measured by the method described later in Examples.

The film made of the (meth)acrylic resin composition of the present invention may be stretched. The stretching process increases the mechanical strength and makes it possible to obtain a film that is less likely to crack. The stretching method is not particularly limited, and includes a simultaneous biaxial stretching method, a sequential biaxial stretching method, a tubular stretching method, a rolling method and the like. The temperature during stretching can be uniformly stretched, and from the viewpoint of obtaining a high-strength film, the lower limit is preferably a temperature 5 ° C. higher than the glass transition temperature of the (meth)acrylic resin (A), and the upper limit is ( The temperature is preferably 40° C. higher than the glass transition temperature of the meth)acrylic resin (A). When the stretching temperature is at least the above lower limit, the film is less likely to break during stretching, and when the stretching temperature is at most the above upper limit, the effect of the stretching treatment can be sufficiently exhibited and the strength of the film can be increased. Stretching is usually carried out at a stretching rate of 100 to 5,000%/min. When the stretching rate is 100%/min or more, the strength of the film can be increased, and the productivity is also improved. Further, when the stretching rate is 5,000%/min or less, the film can be uniformly stretched. Moreover, it is more preferable to heat-set after extending|stretching. A film with less thermal shrinkage can be obtained by heat setting.

The thickness of the film made of the (meth)acrylic resin composition of the present invention is preferably less than 500 μm in an unstretched state (before stretching treatment). When the thickness is less than 500 μm, the laminating property, handling property, cutting property, punching property, and other secondary workability are improved, and the unit cost per unit area can be suppressed, resulting in excellent economic efficiency. The unstretched (before stretching) thickness of the film made of the (meth)acrylic resin composition of the present invention is preferably 30 μm or more, more preferably 50 μm or more. Further, it is more preferably 300 μm or less, still more preferably 200 μm or less, and particularly preferably 100 μm or less.
The thickness of the film made of the (meth)acrylic resin composition of the present invention after stretching is preferably 10 to 200 μm, more preferably 30 to 60 μm.

The film made of the (meth)acrylic resin composition of the present invention may be colored. As a coloring method, a method of adding a pigment or a dye to color the (meth)acrylic resin composition itself before film formation; Examples include a dyeing method in which the material is colored by heating, but the method is not particularly limited to these.

At least one surface of the film made of the (meth)acrylic resin composition of the present invention may be printed. Patterns such as pictures, characters, figures, etc., and colors can be imparted by printing. The pattern may be chromatic or achromatic.

The film made of the (meth)acrylic resin composition of the present invention has, on at least one surface, (i) a layer made of a metal and/or a metal oxide, (ii) a thermoplastic resin layer and (iii) a substrate layer. A laminated film in which at least one layer is laminated as another layer may be used. The method of laminating other layers is not particularly limited, and they can be bonded directly or via an adhesive layer. As the base material layer, for example, a wooden base material, a non-woody fiber such as kenaf, or the like may be used. As for the other layer, only one layer may be laminated, or a plurality of layers may be laminated.

Examples of thermoplastic resins suitable for lamination include polycarbonate resins, polyethylene terephthalate resins, polyamide resins, polyethylene resins, polypropylene resins, polystyrene resins, polyvinyl chloride resins, (meth)acrylic resins other than (A) (meth)acrylic resins, Examples include ABS resins, ethylene-vinyl alcohol resins, polyvinyl butyral resins, polyvinyl acetal resins, styrene thermoplastic elastomers, olefin thermoplastic elastomers, and acrylic thermoplastic elastomers.

The thickness of the laminated film is not particularly limited because it can vary depending on the application, but from the viewpoint of secondary workability, it is preferably 500 μm or less.

The film made of the (meth)acrylic resin composition of the present invention may be used alone, as an inner layer or part thereof of a laminate, or as the outermost layer of a laminate. Other resins used for lamination are preferably transparent resins such as methacrylic resins from the viewpoint of film design. The film forming the outermost layer preferably has high surface hardness and high weather resistance from the viewpoint of the film being scratch resistant and the design lasting for a long time. is preferred.

The film made of the (meth)acrylic resin composition of the present invention has low haze, good optical properties, high surface hardness, excellent flex resistance and impact resistance, and less fish-eye defects. Taking advantage of these excellent features, the (meth)acrylic resin film of the present invention is suitably used as a decorative film, an optical film, and the like. A specific example of the optical film is a polarizer protective film. The polarizer protective film can be used in a polarizing plate including it, and in an image display device such as a liquid crystal display device, an organic EL display device, and a PDP including at least one polarizing plate. Films made from the (meth)acrylic resin composition of the present invention include light guide films, moth-eye films, Fresnel lenses, lenticular lenses, front films for various displays, diffusion films, anti-scattering films for glass, liquid crystal ASF films, and transparent conductive films. , a heat shield film, various barrier films, and the like.

As a more specific example, a film made of the (meth)acrylic resin composition of the present invention has a low haze, good optical properties, high surface hardness, excellent flex resistance and impact resistance, and a fish eye resistance. Making use of characteristics such as few defects, molded products that require designability and molded products that require advanced optical characteristics, namely signboard parts such as advertising towers, stand signboards, side signboards, transom signboards, rooftop signboards, etc. Display parts such as showcases, partitions, and store displays; Lighting parts such as fluorescent lamp covers, mood lighting covers, lampshades, light ceilings, light walls, and chandeliers; Interior parts such as furniture, pendants, and mirrors; , safety window glass, partitions, stair waistboards, balcony waistboards, roofs of leisure buildings, etc.; aircraft windshields, visors for pilots, windshields for motorcycles and motorboats, light shielding plates for buses, side visors for automobiles, rear visors, heads Automotive parts such as wings, headlight covers, automobile interior parts, and automobile exterior parts such as bumpers; audiovisual nameplates, stereo covers, television protective masks, electronic equipment parts such as vending machines, mobile phones, and personal computers; Medical device parts such as instruments and X-ray parts; Equipment-related parts such as machine covers, instrument covers, laboratory equipment, rulers, dials, observation windows; Traffic-related parts such as road signs, information boards, curved mirrors, and soundproof walls; , greenhouses, large water tanks, box water tanks, bathroom materials, clock panels, bathtubs, sanitary items, desk mats, game parts, toys, surface decorative and protective films such as masks for face protection during welding, wallpaper, marking films, etc. It can be suitably used for

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples. In addition, the present invention is not limited to the following examples. In addition, the present invention encompasses all aspects in which the above-mentioned characteristic values, forms, manufacturing methods, applications, and other technical characteristics are arbitrarily combined. Incidentally, the measurement of physical properties and the like in Examples and Comparative Examples were carried out by the following methods.

[Weight average molecular weight (Mw)]
A chromatogram was measured by gel permeation chromatography (GPC) under the following conditions, and a value converted to the molecular weight of standard polystyrene was calculated. The baseline is the point where the slope of the high molecular weight peak on the GPC chart changes from zero to positive when viewed from the early retention time, and the point where the slope of the low molecular weight peak changes from negative to zero when viewed from the early retention time. A line connecting the points where
GPC device: HLC-8320 manufactured by Tosoh Corporation
Detector: Differential refractive index detector Column: Two TSKgel SuperMultipore HZMMs manufactured by Tosoh Corporation and SuperHZ4000 connected in series were used.
Eluent: Tetrahydrofuran Eluent flow rate: 0.35 mL/min Column temperature: 40°C
Calibration curve: Created using 10 standard polystyrene data

[Average particle size]
It was measured using a laser diffraction/scattering particle size distribution analyzer LA-910 manufactured by Horiba, Ltd.

[Glass transition temperature (Tg)]
The glass transition temperature of the (meth)acrylic resin (A) was measured according to JIS K7121:2012. That is, the sample is heated to 200°C once, then cooled to 30°C or less, and then heated from 30°C to 200°C at a rate of 10°C/min. The midpoint glass transition temperature obtained from the DSC curve measured during the second heating was taken as the glass transition temperature in the present invention.

[Melt viscosity]
Using a capillograph (model 1D manufactured by Toyo Seiki Seisakusho Co., Ltd., capillary diameter 1 mmφ, length 40 mm), measurement was performed under the predetermined temperature and shear rate conditions described in Table 1.

[Long-term stability during melting]
5 g of the (meth)acrylic resin composition obtained in each Example or Comparative Example was added to a metal screw tube containing a polytetrafluoroethylene sheet, and left in a hot air dryer at 270° C. for 24 hours. One piece was taken from the central part of the sample before and after heating, and a section was cut out with a microtome, mounted on a grid, stained with osnic acid, and observed with a transmission electron microscope. Based on the particle aggregation state of the core-shell type graft copolymer at that time, the long-term stability during melting was evaluated according to the following criteria.
A: Few parts are aggregated, no change is observed B: Aggregation is progressing as a whole C: Aggregation is occurring violently

〔thickness〕
A thickness of 100 mm from the central portion and both ends of the film produced in each Example or Comparative Example was measured with a micrometer at three points in total, and the average value was taken as the thickness of the film.

[Fisheye defect]
A 300 m roll of film produced in each example or comparative example is passed through an online defect inspector (Scantec 8000C1 System 3, manufactured by Nagase & Co., Ltd.), and the number of fish eye defects having a size of 0.03 mm ² or more is measured ^. , the number of fisheye defects was calculated.

[Haze]
A 50 mm×50 mm piece was cut from the film produced in each example or comparative example to obtain a test piece, and the haze was measured at 23° C. in accordance with JIS K7136:2000.

〔Pencil hardness〕
A 10 cm×10 cm piece was cut from the film produced in each example or comparative example to obtain a test piece, and the pencil hardness was measured according to JIS K5600-5-4:1999.

[Flexibility]
A piece of 15 mm×110 mm was cut out from the film produced in each example or comparative example to obtain a test piece, and the folding endurance was measured according to JIS P8115:2001.

[Reference example 1]
Production of (meth) acrylic resin (A-1-1) 99 parts by mass of methyl methacrylate and 1 part by mass of methyl acrylate, a polymerization initiator (2,2'-azobis (2-methylpropionitrile), hydrogen abstraction ability : 1%, 1-hour half-life temperature: 83°C) and 0.24 parts by mass of a chain transfer agent (n-octyl mercaptan) were added and dissolved to obtain a raw material liquid.
A mixture was obtained by mixing 100 parts by mass of ion-exchanged water, 0.03 parts by mass of sodium sulfate and 0.45 parts by mass of a suspension dispersant. A pressure-resistant polymerization tank was charged with 420 parts by mass of the mixed liquid and 210 parts by mass of the raw material liquid, and the temperature was raised to 70° C. to initiate a polymerization reaction while stirring in a nitrogen atmosphere. After 3 hours from the initiation of the polymerization reaction, the temperature was raised to 90° C. and stirring was continued for 1 hour to obtain a liquid in which the bead-like copolymer was dispersed. A small amount of polymer adhered to the wall surface of the polymerization vessel or to the stirring blades, but no bubbling occurred and the polymerization reaction proceeded smoothly.
The resulting copolymer dispersion was washed with an appropriate amount of ion-exchanged water, and the bead-like copolymer was taken out with a bucket-type centrifuge and dried with a hot air dryer at 80° C. for 12 hours. ) An acrylic resin (A-1-1) was obtained.
The obtained (meth)acrylic resin (A-1-1) has a methyl methacrylate unit content of 99% by mass, a methyl acrylate unit content of 1% by mass, and a weight average molecular weight (Mw ) was 95,000 and the glass transition temperature was 120°C.

[Reference example 2]
Production of (meth)acrylic resin (A-1-2) Reference example except that the monomer used was changed to 100 parts by mass of methyl methacrylate and the amount of chain transfer agent was changed to 0.21 parts by mass A (meth)acrylic resin (A-1-2) was obtained in the same manner as in Example 1.
The obtained (meth)acrylic resin (A-1-2) had a methyl methacrylate unit content of 100% by mass, a weight average molecular weight (Mw) of 113,000, and a glass transition temperature of 121°C. rice field.

[Reference example 3]
Production of (meth)acrylic resin (A-2-1) The monomers used were changed to 90 parts by mass of methyl methacrylate and 10 parts by mass of methyl acrylate, and the amount of chain transfer agent was changed to 0.39 parts by mass. A (meth)acrylic resin (A-2-1) was obtained in the same manner as in Reference Example 1, except that
The obtained (meth)acrylic resin (A-2-1) has a methyl methacrylate unit content of 90% by mass, a methyl acrylate unit content of 10% by mass, and a weight average molecular weight of 60. ,000 and the glass transition temperature was 111°C.

[Reference Example 4]
Production of Core-Shell Graft Copolymer (B-1) (1) Into a reactor equipped with a stirrer, thermometer, nitrogen gas inlet tube, monomer inlet tube and reflux condenser, 1050 parts by mass of ion-exchanged water , 0.3 parts by mass of sodium polyoxyethylene tridecyl ether acetate and 0.7 parts by mass of sodium carbonate were charged, and the inside of the reactor was sufficiently replaced with nitrogen gas. The internal temperature was then raised to 80°C. 0.25 parts by mass of potassium persulfate was added thereto and stirred for 5 minutes. To this, 245 parts by mass of a monomer mixture consisting of 95.4% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.2% by mass of allyl methacrylate was continuously added dropwise over 60 minutes. After completion of the dropwise addition, the polymerization reaction was further carried out for 30 minutes so that the polymerization conversion rate was 98% or higher.
(2) Next, 0.32 parts by mass of potassium persulfate was put into the same reactor and stirred for 5 minutes. After that, 315 parts by mass of a monomer mixture consisting of 80.5% by mass of butyl acrylate, 17.5% by mass of styrene and 2% by mass of allyl methacrylate was dropped continuously over 60 minutes. After completion of the dropwise addition, the polymerization reaction was further carried out for 30 minutes so that the polymerization conversion rate was 98% or higher.
(3) Next, 0.14 parts by mass of potassium persulfate was put into the same reactor and stirred for 5 minutes. Thereafter, 140 parts by mass of a monomer mixture consisting of 95.2% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.4% by mass of n-octylmercaptan was continuously added dropwise over 30 minutes. After completion of the dropwise addition, the polymerization reaction was further carried out for 60 minutes so that the polymerization conversion rate was 98% or higher.
A latex containing the core-shell type graft copolymer (B-1) was obtained by the above operation. A latex containing the core-shell type graft copolymer (B-1) was frozen and solidified. Then, it was washed with water and dried to obtain a particulate core-shell type graft copolymer (B-1). The average particle diameter of the particles was 0.23 μm.

The following were used as other materials.
<Aliphatic alcohol (C)>
Kao "Kalcol 8098", stearyl alcohol <polymer processing aid (D)>
"Paraloid" K125P manufactured by Dow Chemical Company
<Ultraviolet inhibitor (E)>
ADEKA's "ADEKA STAB" LA31RG

[Example 1]
(Meth) acrylic resin (A-1-1) 70 parts by mass, (meth) acrylic resin (A-2-1) 10 parts by mass, core-shell type graft copolymer (B-1) 20 parts by mass, aliphatic alcohol (C) 0.05 parts by mass and UV inhibitor (E) 2.0 parts by mass are controlled by a weight feeder, and a 41 mm diameter twin-screw kneading extruder (Toshiba Kikai TEM41-SS, with a polymer filter with a filtration accuracy of 10 μm). by setting the temperature under the hopper to 150 ° C., the barrel temperature, and the polymer filter temperature to 230 ° C., extruding the (meth)acrylic resin composition into strands and cutting it with a pelletizer to obtain ( Pellets of a meth)acrylic resin composition were produced.
The obtained pellets were placed in a vented 65 mmφ uniaxial extruder equipped with a gear pump and a polymer filter with a filtration accuracy of 10 μm in this order. (Film forming temperature including the temperature from the vent to the T-die) 270°C, extruded at a discharge rate of 40 kg/h, sandwiched between a metal mirror-surface elastic roll at 80°C and a metal mirror-surface rigid roll at 80°C to form a film, It was drawn at 10 m/min to form a film having a thickness of 75 μm. Table 1 shows the evaluation results of the obtained film. The fisheye defects were inspected online during film formation.

[Examples 2 to 5]
A film was obtained in the same manner as in Example 1, except that the formulation shown in Table 1 was used. The evaluation results are shown in Table 1.

[Example 6]
A film was obtained in the same manner as in Example 5 except that the melt extrusion temperature (film forming temperature including the temperature from the vent to the T die) shown in Table 1 was used. The evaluation results are shown in Table 1.

[Comparative Examples 1 and 2]
A film was obtained in the same manner as in Example 1, except that the added amount of the aliphatic alcohol (C) shown in Table 1 was used. The evaluation results are shown in Table 1. It was suggested that the long-term stability during melting was insufficient both when the aliphatic alcohol (C) was not added and when it was added as much as 0.5 parts by mass, making long-term continuous operation difficult.

[Comparative Example 3]
A film was obtained in the same manner as in Example 1, except that an aliphatic ester (“Excel” T95, stearyl monoglyceride, manufactured by Kao Corporation) was used instead of the aliphatic alcohol (C). The evaluation results are shown in Table 1. It was suggested that when an aliphatic ester is used, long-term stability during melting is insufficient, making long-term continuous operation difficult.

[Comparative Examples 4 to 6]
A film was obtained in the same manner as in Example 1, except that the formulation shown in Table 1 was used. The evaluation results are shown in Table 1. When the core-shell type graft copolymer (B) was not added, the fish-eye defect was small, but the folding endurance value was low, resulting in poor bending resistance.

Claims (9)

A total of 100 parts by mass of the (meth)acrylic resin (A) and the core-shell type graft copolymer (B),
Contains 0.03 to 0.3 parts by mass of an aliphatic alcohol (C),
The mass ratio of the (meth)acrylic resin (A) and the core-shell type graft copolymer (B) is the former/latter=70/30 to 90/10.
A film made of a (meth)acrylic resin composition,
The film is a decorative film, an optical film, or a polarizer protective film. The film according to claim 1, wherein the (meth)acrylic resin composition has a melt viscosity of 2,000 Pa·s or less at 270°C and a shear rate of 12.2/sec. The film according to claim 1 or 2, wherein the (meth)acrylic resin (A) contains at least two types of (meth)acrylic resins having different weight average molecular weights. A film according to any one of claims 1 to 3 , wherein said fatty alcohol (C) is stearyl alcohol. The film according to any one of claims 1 to 4 , wherein the (meth)acrylic resin composition further contains 0.1 to 3% by mass of a polymer processing aid (D). A film according to any preceding claim, having a pencil hardness of HB or higher . The film according to any one of claims 1 to 6 , which has a folding endurance of 30 times or more. A polarizing plate comprising the film according to any one of claims 1 to 7 , which is a polarizer protective film. (Meth) acrylic resin (A) and core-shell type graft copolymer (B) totaling 100 parts by mass, and 0.03 to 0.3 parts by mass of aliphatic alcohol (C), the (meth) acrylic resin A method for producing a film made of a (meth)acrylic resin composition, wherein the mass ratio of (A) to the core-shell type graft copolymer (B) is the former/latter = 70/30 to 90/10, A method for producing a film, using an extruder equipped with a vent, a gear pump, a polymer filter and a T-die in this order, and controlling the temperature from the vent to the T-die at 230 to 290°C.