JP7278810B2 - Acrylic resin film and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an acrylic resin film, a method for producing the same, and a laminated film using the acrylic resin film.

Acrylic resin film is classified into display materials such as signboards and flat panel displays, and decorative films, taking advantage of its features such as high transparency, high surface hardness, excellent weather resistance, and ease of molding. It is used in various applications such as interior and exterior materials for buildings, interior and exterior materials for building materials, and interior members. Acrylic resin films are used as surface layer materials for various members because they have excellent surface properties.

Acrylic resin films have the above characteristics, but (meth)acrylic resin itself has the drawback of being brittle, so techniques such as imparting toughness using multi-layer structure polymer particles are used. It is In particular, among films for building materials, films with good stretchability and folding endurance are required for use as decoration films for resin sashes in order to conform to complicated shapes.
For example, Patent Document 1 proposes an acrylic film containing mica and acrylic multilayer structure particles having a crosslinked elastic polymer layer as an inner layer and a thermoplastic polymer layer as an outermost layer.

WO2017/141873

However, when a thin film is formed by melt extrusion using multi-layer structure polymer particles, the neck-in at both ends of the melt curtain pulled down from the die, called draw resonance, and the thickness periodically fluctuate greatly. Therefore, it is difficult to produce a thin film with excellent uniformity of thickness at a high line speed, and this tendency is remarkable especially when the content of the multi-layer structure polymer particles is large.

The present invention has been made in view of the above circumstances, and an acrylic resin film that maintains the toughness of the film and has excellent folding resistance and film-forming properties, a method for producing the same, and a method for producing the acrylic resin film An object of the present invention is to provide a laminated film.

As a result of intensive studies conducted by the present inventors in order to achieve the above object, a (meth)acrylic resin composition comprising specific acrylic multilayer structure polymer particles and a specific polymer processing aid The inventors have found that an acrylic resin film can solve the problem, and have completed the present invention.

That is, the present invention provides the following [1] to [12].
[1] An acrylic resin film made of a (meth)acrylic resin composition (R) containing acrylic multilayer structure polymer particles (A) and a polymer processing aid (B),
The acrylic multilayer structure polymer particles (A) have an average particle size of 10 to 200 nm as observed by TEM, and the polymer processing aid (B) is an acrylic resin having an average degree of polymerization of 20,000 or more. the film.
[2] The above [1], wherein the tensile elongation at break measured under the conditions of a temperature of 23° C. and a tensile speed of 20 mm/min is 80% or more, and the tensile strength at break measured under the conditions is 30 MPa or more. acrylic resin film.
[3] The above [1], wherein the number of folds of the acrylic resin film measured in accordance with JIS P8115 (2001) in the longitudinal direction (MD direction) and the width direction (TD direction) is 100 or more. Or the acrylic resin film according to [2].
[4] The acrylic resin film according to any one of [1] to [3] above, which has a trouser tear strength of 1.0 N/mm or more as measured according to JIS K7128-1 (1998).
[5] The polymer processing aid (B) comprises 60% by mass or more of methyl methacrylate monomer units and 40% by mass or less of vinyl monomer units, and the (meth)acrylic resin composition ( R) The acrylic resin film according to any one of [1] to [4] above, wherein the content of the polymer processing aid (B) is 0.1 to 7% by mass relative to the total amount.
[6] The (meth)acrylic resin composition (R) further contains a methacrylic resin (C) having an average degree of polymerization of 2,000 or less, and the total amount of the (meth)acrylic resin composition (R) The acrylic resin film according to any one of [1] to [5] above, wherein the content of the methacrylic resin (C) is 1 to 50% by mass.
[7] The acrylic resin film according to any one of [1] to [6] above, wherein the (meth)acrylic resin composition (R) further contains a benzotriazole ultraviolet absorber.
[8] The acrylic resin film according to any one of [1] to [7] above, which is printed on at least one surface.
[9] The acrylic resin film according to any one of [1] to [7], which is a decorative film.
[10] The acrylic resin film according to any one of [1] to [7], which is a building material film.
[11] On at least one surface of the acrylic resin film according to any one of [1] to [10], a layer made of one or more selected from metals and metal oxides, a thermoplastic resin layer, or a substrate A laminated film comprising material layers.
[12] A step of melt extruding the (meth)acrylic resin composition (R) from a T-die into a film, and extruding the melt extruded from the T-die into a pair of rigid metal rolls and/or elastic metal rolls. The method for producing an acrylic resin film according to any one of the above [1] to [10], which has a step of sandwiching it with cooling rolls.

According to the present invention, it is possible to provide an acrylic resin film that maintains the toughness of the film and is excellent in folding endurance and film formability, a method for producing the same, and a laminated film using the acrylic resin film. .

An example of an embodiment to which the present invention is applied will be described below. Numerical values specified in this specification are values determined by the methods disclosed in the embodiments or examples. It should be noted that other embodiments are also included in the scope of the present invention as long as they match the gist of the present invention. As used herein, “(meth)acryl” means “acryl or methacryl”. Moreover, the resin film which consists of a (meth)acrylic-type resin composition may be called an "acrylic-type resin film." Furthermore, "acrylic resin film" may be described as "acrylic film" or "film".

The acrylic resin film of the present invention is an acrylic resin film made of a (meth)acrylic resin composition (R) containing acrylic multilayer structure polymer particles (A) and a polymer processing aid (B). There is
The acrylic multilayer structure polymer particles (A) have an average particle diameter of 10 to 200 nm as observed by TEM, and the polymer processing aid (B) has an average degree of polymerization of 20,000 or more. and

<(Meth)acrylic resin composition (R)>
The (meth)acrylic resin composition (R) contains acrylic multilayer structure polymer particles (A) and a polymer processing aid (B).

(Acrylic multilayer structure polymer particles (A))
The acrylic multilayer structure polymer particles (A) used in the present invention are not particularly limited as long as they have a multilayer structure. For example, at least one inner layer has an alkyl group with 1 to 8 carbon atoms. A crosslinked elastic polymer layer containing acrylic acid alkyl ester monomer units and/or conjugated diene monomer units as main component monomer units, and the outermost layer has an alkyl group having 1 to 8 carbon atoms. It is preferably a thermoplastic polymer layer containing methacrylic acid alkyl ester monomer units as main component monomer units.
In this specification, unless otherwise specified, the "main component monomer unit" is a monomer unit of 50% by mass or more.

Examples of alkyl acrylates having 1 to 8 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, propyl acrylate and cyclohexyl acrylate. Among these, methyl acrylate, butyl acrylate and 2-ethylhexyl acrylate are preferred, and butyl acrylate is more preferred. Examples of diene-based monomers include 1,3-butadiene and isoprene.

The acrylic multilayer structure polymer particle (A) in the present invention is a so-called core in which one or more inner layers including at least one crosslinked elastic polymer layer are covered with the outermost rigid thermoplastic polymer layer. /Shell structure rubber particles are preferred.

The number of layers of the acrylic multilayer structure polymer particles (A) is not particularly limited, and may be two layers, three layers, or four layers or more. In terms of thermal stability and productivity, the acrylic multilayer structure polymer particles (A) preferably have a three-layer structure.

In the acrylic multilayer structure polymer particles (A), the crosslinked elastic polymer layer constituting at least one inner layer excluding the outermost layer is connected by graft bonding between the molecular chains of this layer and the molecular chains in the adjacent layer. It is preferable that

The crosslinked elastic polymer layer may contain an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and/or a diene-based monomer, and a vinyl-based monomer copolymerizable therewith. .
Examples of copolymerizable vinyl monomers include maleimide compounds such as N-propylmaleimide, N-cyclohexylmaleimide, and No-chlorophenylmaleimide; ethylene glycol dimethacrylate, propylene glycol dimethacrylate, triethylene glycol. polyfunctional monomers such as dimethacrylate, hexanediol dimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, triethylene glycol diacrylate, allyl methacrylate, and triallyl isocyanurate;
In addition, in this specification, a "polyfunctional monomer" is a monomer having two or more polymerizable functional groups.

From the viewpoint of impact resistance, etc., the total content of acrylic acid alkyl ester monomer units and/or conjugated diene monomer units having alkyl groups of 1 to 8 carbon atoms in the crosslinked elastic polymer layer is , preferably 60% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass or more.

The acrylic multilayer structure polymer particles (A) in the present invention contain, from the center side, 30 to 98.99% by mass of methyl methacrylate monomer units and 1 to 70% by mass of alkyl groups having 1 to 1 carbon atoms. A first layer composed of a crosslinked resin layer containing an acrylic acid alkyl ester monomer unit of 8 and 0.01 to 2% by mass of a polyfunctional monomer unit, and 70 to 99.9% by mass of an alkyl Alkyl acrylate monomer units in which the group has 1 to 8 carbon atoms, 0 to 30% by mass of methyl methacrylate monomer units, and 0.1 to 5% by mass of polyfunctional monomer units 70 to 100% by mass of methacrylic acid alkyl ester monomer units, and 0 to 30% by mass of acrylic acid in which the number of carbon atoms in the alkyl group is 1 to 8 More preferably, it is a three-layer structure polymer particle comprising a third layer comprising a rigid thermoplastic resin layer containing an alkyl ester monomer unit.

In the three-layer structure polymer particles, the ratio of each layer is not particularly limited, but the first layer (innermost layer) is 5 to 40% by mass, the second layer (intermediate layer) is 20 to 55% by mass, and the second layer (intermediate layer) is 20 to 55% by mass. The three layers (outermost layer) are preferably 40 to 75% by mass.

Examples of methacrylic acid alkyl esters used in the outermost rigid thermoplastic polymer layer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate. From the viewpoint of dispersibility of the acrylic multilayer structure polymer particles (A), the content of the methacrylic acid alkyl ester monomer unit in the rigid thermoplastic polymer layer is preferably 70% by mass or more, more preferably It is 80% by mass or more.

The average particle size of the acrylic multilayer structure polymer particles (A) is 10 to 200 nm. When the average particle size is less than 10 nm, the impact resistance and handleability of the acrylic multilayer structure polymer particles (A) tend to deteriorate. On the other hand, when the average particle size is more than 200 nm, when stress is applied to the acrylic resin film of the present invention, it tends to whiten and the light transmittance tends to decrease (stress whitening resistance deteriorates). be. From the viewpoint of stress whitening resistance, impact resistance, handleability, etc., the lower limit of the average particle size of the acrylic multilayer structure polymer particles (A) is preferably 40 nm, more preferably 70 nm, and the upper limit is preferably 150 nm, more preferably 110 nm.
The average particle size is the average particle size of the acrylic multilayer structure polymer particles (A) in the latex state. 300".

In the production process of the acrylic resin film of the present invention, the non-crosslinked outermost layer and the like of the acrylic multilayer structure polymer particles (A) may melt to form a matrix. In this case, the average particle size of the acrylic multilayer structure polymer particles (A) in the film is smaller than the average particle size of the raw acrylic multilayer structure polymer particles.
In this specification, unless otherwise specified, the average particle size of the acrylic multilayer structure polymer particles (A) in the film was determined by cross-sectional observation with a transmission electron microscope (TEM) while the particles were present in the film. use the value. The average particle size can be determined by the method described in Examples.

The acrylic multilayer structure polymer particles (A) in the film have an average particle diameter of 10 to 200 nm as determined by TEM observation. When the average particle size as determined by TEM observation is less than 10 nm, the handleability of the acrylic multilayer structure polymer particles (A) tends to deteriorate, and the toughness of the obtained acrylic resin film tends to deteriorate. On the other hand, when the average particle size by TEM observation is more than 200 nm, when stress is applied to the acrylic resin film of the present invention, it tends to whiten and the light transmittance tends to decrease (stress whitening resistance deteriorates )Tend. From the viewpoint of stress whitening resistance and impact resistance, the lower limit of the average particle size of the acrylic multilayer structure polymer particles (A) observed by TEM is preferably 30 nm, more preferably 60 nm, and the upper limit is , preferably 150 nm, more preferably 100 nm.

Although the method for producing the acrylic multilayer structure polymer particles (A) is not particularly limited, it is preferably produced by an emulsion polymerization method. First, one or more raw material monomers are emulsion-polymerized to prepare core particles, and then one or more other monomers are emulsion-polymerized in the presence of core particles to form core particles. form a shell around the Then, if necessary, one or more monomers are emulsion-polymerized in the presence of the core-shell particles to form another shell. By repeating such a polymerization reaction, the desired acrylic multilayer structure polymer particles (A) can be produced as an emulsified latex. The resulting latex usually contains a linear (meth)acrylic resin having methyl methacrylate monomer units in addition to the crosslinked or grafted acrylic multilayer structure polymer particles. Both are combined to form acrylic multilayer structure polymer particles (A).

Emulsifiers used in emulsion polymerization are not particularly limited, but include anionic emulsifiers, nonionic emulsifiers, and nonionic/anionic emulsifiers. One or more of these emulsifiers can be used.
Examples of anionic emulsifiers include dialkylsulfosuccinates such as sodium dioctylsulfosuccinate and sodium dilaurylsulfosuccinate; alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate; and alkylsulfates such as sodium dodecylsulfate.
Examples of nonionic emulsifiers include polyoxyethylene alkyl ethers and polyoxyethylene nonylphenyl ethers.
Nonionic/anionic emulsifiers include polyoxyethylene nonylphenyl ether sulfates such as sodium polyoxyethylene nonylphenyl ether sulfate; polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene alkyl ether sulfate; polyoxyethylene tridecyl ether Examples thereof include alkyl ether carboxylates such as sodium acetate.
The number of added moles of oxyethylene units in the nonionic emulsifier or nonionic/anionic emulsifier exemplified compound is generally 30 mol or less, preferably 20 mol or less, in order to prevent the foaming property of the emulsifier from becoming extremely large. and more preferably 10 mol or less.
The amount of the emulsifier used can be appropriately set, for example, so that the average particle size of the acrylic multilayer structure polymer particles (A) is within the above range.

Polymerization initiators used for emulsion polymerization are not particularly limited, and persulfate initiators such as potassium persulfate and ammonium persulfate; redox initiators such as persulfoxylate/organic peroxide and persulfate/sulfite. initiators and the like.

A chain transfer agent can be used for emulsion polymerization as needed. Chain transfer agents include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan, and sec-butyl mercaptan.

In the emulsion polymerization of each layer, raw materials such as monomers, emulsifiers, polymerization initiators, and chain transfer agents can be added to the polymerization reaction system by any known method such as a batch addition method, a divided addition method, and a continuous addition method. method.

The polymerization reaction temperature of each layer is preferably 30 to 120°C, more preferably 50 to 100°C. The polymerization reaction time for each layer varies depending on the types and amounts of the polymerization initiator and emulsifier used, and the polymerization temperature, but each layer is usually 0.5 to 7 hours. The mass ratio of the monomer and water (monomer/water) is preferably 1/20 to 1/1.

The acrylic multi-layer structure polymer particles (A) are obtained by subjecting the polymer latex produced by emulsion polymerization to coagulation, dehydration, drying, etc., according to a known method to obtain a powdery polymer. can be recovered as Methods for separating and recovering the powdery acrylic multilayer structure polymer particles (A) include a salting-out coagulation method, a freeze-coagulation method, a spray drying method, and the like. Among them, the salting-out coagulation method and the freeze-coagulation method are preferable because impurities can be easily removed by washing with water. Prior to the coagulation step, it is preferable to carry out a step of filtering using a wire mesh having an opening of 50 μm or less for the purpose of removing foreign substances mixed in the emulsion.

The (meth)acrylic resin composition (R) may contain two or more kinds of acrylic multilayer structure polymer particles (A).
The content of the acrylic multilayer structure polymer particles (A) relative to the total amount of the (meth)acrylic resin composition (R) is preferably 60% by mass or more, more preferably 70% by mass or more, and still more preferably It is 80% by mass or more, preferably 98% by mass or less, more preferably 96% by mass or less, and still more preferably 94% by mass or less. When the content of the acrylic multilayer structure polymer particles (A) is 60% by mass or more, physical properties such as folding endurance and tensile elongation at break can be improved. can improve sexuality.

(Polymer processing aid (B))
The polymer processing aid (B) used in the present invention has an average degree of polymerization of 20,000 or more. If the average degree of polymerization of the polymer processing aid (B) is less than 20,000, compatibility with the acrylic multilayer structure polymer particles (A) may deteriorate, and physical properties such as tensile elongation at break may deteriorate. . From this point of view, the average degree of polymerization of the polymer processing aid (B) is preferably 21,000 or more, more preferably 22,000 or more. Moreover, from the viewpoint of improving film formability, it is preferably 40,000 or less, more preferably 33,000 or less, and still more preferably 30,000 or less.
The average degree of polymerization can be measured by a viscosity method, and more specifically by the method described in Examples.

The polymer processing aid (B) can be produced, for example, by an emulsion polymerization method.

The polymer processing aid (B) is not particularly limited as long as it has an average degree of polymerization of 20,000 or more. It is preferable to consist of 40% by mass or less of units. The content of the methyl methacrylate monomer unit is more preferably 65 to 95% by mass, more preferably 70 to 90% by mass, in terms of compatibility with the acrylic multilayer structure polymer particles (A). , 75 to 85% by mass. The content of vinyl-based monomer units is more preferably 5 to 35% by mass, even more preferably 10 to 30% by mass, even more preferably 15 to 25% by mass.

The type of vinyl-based monomer copolymerizable with methyl methacrylate is not particularly limited. - Acrylic acid ester monomers such as ethylhexyl, phenyl acrylate and benzyl acrylate; ethyl methacrylate, butyl methacrylate, propyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate and benzyl methacrylate methacrylic acid esters; aromatic vinyl compounds such as vinyl acetate, styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, α-methylstyrene, and vinylnaphthalene; nitriles such as acrylonitrile and methacrylonitrile; α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; and maleimide compounds such as N-ethylmaleimide and N-cyclohexylmaleimide. These can be used alone or in combination of two or more. Among these, methyl acrylate and butyl acrylate are preferred, and butyl acrylate is more preferred, in terms of compatibility with the acrylic multilayer structure polymer particles (A).

The content of the polymer processing aid (B) with respect to the total amount of the (meth)acrylic resin composition (R) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further It is preferably 1% by mass or more, and preferably 7% by mass or less, more preferably 5.5% by mass or less, still more preferably 4% by mass or less, and even more preferably 2.5% by mass. % or less. When the content of the polymer processing aid (B) is 0.1% by mass or more, the film formability can be improved, and when it is 7% by mass or less, the acrylic multilayer structure polymer particles (A) It is possible to maintain the film toughness due to, and suppress the increase in viscosity due to the polymer processing aid (B).

Commercially available products can be used as the polymer processing aid (B), and specific examples include METABLEN (registered trademark) P type manufactured by Mitsubishi Chemical Corporation, Paraloid series manufactured by Dow Chemical Co., and the like. be done. Among them, Metabrene (registered trademark) P530A and Metabrene (registered trademark) P531A are preferable, and Metabrene (registered trademark) P530A is particularly preferable.
1 type(s) or 2 or more types can be used for a polymeric processing aid (B).

The total content of the acrylic multilayer structure polymer particles (A) and the polymer processing aid (B) in the (meth)acrylic resin composition (R) is preferably 60% by mass or more, and more preferably. is 70% by mass or more, more preferably 80% by mass or more. Also, it is preferably 99% by mass or less, more preferably 97% by mass or less, and still more preferably 95% by mass or less.

(Methacrylic resin (C))
It is preferable that the (meth)acrylic resin composition (R) further contains a methacrylic resin (C) having an average degree of polymerization of 2,000 or less from the viewpoint of further improving the film formability.
If the average degree of polymerization of the methacrylic resin (C) exceeds 2,000, the fluidity during melt molding may be reduced. From such a viewpoint, the average degree of polymerization of the methacrylic resin (C) is preferably 1,900 or less, more preferably 1,800 or less, and still more preferably 1,700 or less. Also, it is preferably 1,000 or more, more preferably 1,100 or more, and still more preferably 1,200 or more.
The average degree of polymerization can be measured by a viscosity method, and more specifically by the method described in Examples.

From the viewpoint of the balance between heat resistance and toughness, the methacrylic resin (C) preferably contains 80% by mass or more of methyl methacrylate monomer units, more preferably 90 to 99% by mass, and 92 to 96% by mass. % is more preferable.

By using a methacrylic resin (C) that has a good affinity with the acrylic multilayer structure polymer particles (A) and has a refractive index close to that of the acrylic multilayer structure polymer particles (A), , a highly transparent (meth)acrylic resin composition (R) can be obtained, and as a result, a highly transparent acrylic resin film can be obtained. Moreover, the processability of an acrylic resin film can be improved by containing a methacrylic resin (C).

The methacrylic resin (C) preferably contains 20% by mass or less of copolymerizable vinyl monomer units in addition to methyl methacrylate monomer units. Vinyl monomers are not particularly limited, and examples include methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, and acrylic acrylic acid ester monomers such as benzyl acid; ethyl methacrylate, butyl methacrylate, propyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, and benzyl methacrylate; aromatic vinyl compounds such as p-methylstyrene, o-methylstyrene, m-methylstyrene, α-methylstyrene, and vinylnaphthalene; nitriles such as acrylonitrile and methacrylonitrile; acrylic acid, methacrylic acid, crotonic acid, etc. and α,β-unsaturated carboxylic acids; and maleimide compounds such as N-ethylmaleimide and N-cyclohexylmaleimide. These can be used alone or in combination of two or more.

The weight average molecular weight of the methacrylic resin (C) is preferably 75,000 to 150,000, more preferably 90,000 to 145,000, still more preferably 100,000 to 140,000. When the weight average molecular weight of the methacrylic resin (C) is 75,000 or more, the strength can be improved, and when it is 150,000 or less, the film formability can be improved.
The weight average molecular weight (Mw) can be measured by the method described in Examples.

The intrinsic viscosity of the methacrylic resin (C) is preferably 0.3 to 1.0 dL/g, more preferably 0.4 to 0.8 dL/g. When the intrinsic viscosity of the methacrylic resin (C) is 0.3 dL/g or more, it is possible to suppress a decrease in toughness during melt molding of the (meth)acrylic resin composition (R). In addition, when the intrinsic viscosity of the methacrylic resin (C) is 1.0 dL/g or less, it is possible to suppress a decrease in fluidity during melt molding.

The intrinsic viscosity [η] is calculated by measuring the specific viscosity (η _SP ) in water at 20° C. with an Ubbelohde viscometer and using the following formula (1) (Huggins formula).

η_ＳＰ（ｄＬ／ｇ）：比粘度
［η］（ｄＬ／ｇ）：極限粘度
Ｃ（ｇ／ｄＬ）：ポリマー粘度
Ｋ：ハギンス定数

η _SP (dL/g): Specific viscosity [η] (dL/g): Intrinsic viscosity C (g/dL): Polymer viscosity K: Huggins constant

The methacrylic resin (C) preferably has a melt flow rate (MFR) of 0.5 to 15 g/10 min, more preferably 0.7 to 10 g/10 min at a temperature of 230°C and a load of 3.8 kg. and more preferably 1.0 to 5 g/10 minutes. When the MFR of the methacrylic resin (C) is within the above range, stable film formation can be achieved.
The melt flow rate (MFR) can be measured under the above conditions according to JIS K7210-1 (2014).

The content of the methacrylic resin (C) contained in the (meth)acrylic resin composition (R) is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably. is 5% by mass or more, preferably 50% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. When the content of the methacrylic resin (C) is 1% by mass or more, the workability is improved, and when it is 50% by mass or less, excessive increase in the elastic modulus of the acrylic resin film is suppressed, and flexibility and resistance are improved. Stress whitening resistance can be improved.

As the methacrylic resin (C), one polymerized by a known method can be used. The polymerization method of the methacrylic resin (C) is not particularly limited, and examples thereof include an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method, and the like.

Examples of the methacrylic resin (C) include "Parapet GF" (MFR: 15 g/10 minutes (230°C, 37.3 N)) and "Parapet EH" (MFR: 1.3 g/10 minutes (230°C, 37.3 N). 3N)), "Parapet HRL" (MFR: 2.0 g/10 min (230°C, 37.3 N)), and "Parapet G" (MFR: 8.0 g/10 min (230°C, 37.3 N)) Commercial products such as [all trade names, manufactured by Kuraray Co., Ltd.] or ISO8257-1 regulated products can be used.

(Additive)
The (meth)acrylic resin composition (R) may contain, in addition to the components described above, one or more optional components as long as the objects of the present invention are not impaired.
Optional components include antioxidants, heat deterioration inhibitors, ultraviolet absorbers, light stabilizers, plasticizers, lubricants, release agents, antistatic agents, flame retardants, dyes and pigments, organic pigments, and impact modifiers. , foaming agents, fillers, and various additives such as phosphors.
The timing of addition of the optional component is not particularly limited, and may be added during polymerization of at least one acrylic multilayer structure polymer particle (A), or at least one polymerized acrylic multilayer structure polymer particle. It may be added to (A), or may be added during or after kneading at least one type of acrylic multilayer structure polymer particles (A) and polymer processing aid (B).

(Ultraviolet absorber)
UV absorbers are compounds that have the ability to absorb UV light. A UV absorber is a compound said to have a function of mainly converting light energy into heat energy. Examples of ultraviolet absorbers include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, and formamidines. These can use 1 type(s) or 2 or more types. Among the above, benzotriazoles, triazines, and ultraviolet absorbers having a maximum molar absorption coefficient εmax of 1200 dm ³ ·mol ⁻¹ cm ⁻¹ or less at a wavelength of 380 to 450 nm are preferred, and benzotriazoles are more preferred.

Benzotriazoles are highly effective in suppressing degradation of optical properties such as coloration due to exposure to ultraviolet light. Benzotriazoles include 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (manufactured by BASF; trade name: TINUVIN329), 2-(2H -benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (manufactured by BASF; trade name: TINUVIN234), and 2,2′-methylenebis[6-(2H-benzo Triazol-2-yl)-4-tert-octylphenol] (manufactured by ADEKA Corporation; trade name: ADEKA STAB LA-31RG) and the like are preferable.

The amount of the ultraviolet absorber to be added varies depending on the required light resistance, but when long-term durability is desired, the (meth)acrylic resin composition (R ) to 100 parts by mass, preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3.5 parts by mass, still more preferably 1 to 2.5 parts by mass.

Although the total amount of the various additives is not particularly limited, it is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass of the total amount of the (meth)acrylic resin composition (R). Yes, more preferably 1 to 5% by mass.
From the viewpoint of keeping the overall haze of the acrylic resin film of the present invention low, the (meth)acrylic resin composition (R) preferably does not contain fine particles such as matting agents and light diffusing agents.

[Method for producing acrylic resin film]
The method for molding the acrylic resin film of the present invention is not particularly limited, and examples thereof include an extrusion method, a solution casting method, a melt casting method, an inflation molding method, and a blow molding method. Among them, an extrusion molding method is preferable, and a step of melt extruding the (meth)acrylic resin composition (R) from a T die into a film, and a melt extruded into a film (hereinafter simply referred to as "melt" is sandwiched between a pair of cooling rolls consisting of a rigid metal roll and/or a metal elastic roll. According to the extrusion molding method, the film formability of the film is improved, the unevenness of the film, unevenness in thickness, and the occurrence of streaks can be suppressed, the transparency is high, the uniformity of the thickness is high, and the surface is smooth. A film with good properties can be obtained with relatively high productivity.

(Extruder with T-die, roll)
In the extrusion molding method, an extruder with a T-die is preferably used. The extruder with a T die heats and melts the (meth)acrylic resin composition (R) that is charged with a raw material input unit such as a hopper into which the (meth)acrylic resin composition (R) is input, and T It comprises at least a screw part for sending out to the die side and a T-die for extruding the heat-melted (meth)acrylic resin composition (R) into a film.

In the extruder with a T-die, the (meth)acrylic resin composition (R) in a molten state is preferably fed to the T-die in fixed amounts using a gear pump. Thereby, a film with high thickness accuracy can be manufactured.
The molten (meth)acrylic resin composition (R) is preferably supplied to the T-die after impurities are removed by filtration using a polymer filter or the like. The set temperature of the extruder with a T-die is not particularly limited, and is appropriately set according to the composition of the (meth)acrylic resin composition (R), preferably 160 to 280 ° C., more preferably 220 to 275 ° C. and more preferably 250 to 270°C. The set temperature of the extruder with a T-die is the melting temperature (processing temperature) of the (meth)acrylic resin composition (R).

The (meth)acrylic resin composition (R) melted at the above temperature is extruded vertically downward in the form of a film from the outlet of the T-die. The temperature distribution of the T-die is preferably ±15° C. or less, more preferably ±5° C. or less, still more preferably ±1° C. or less. When the temperature distribution of the T-die is ±15° C. or less, the (meth)acrylic resin composition (R) in a molten state does not have uneven viscosity, and the obtained film has uneven thickness, distortion due to stress unevenness, etc. can be suppressed.

Examples of the method for cooling the melt extruded from the T-die include a nip roll method, an electrostatic application method, an air knife method, a calendar method, a single-sided belt method, a double-sided belt method, and a three-roll method, and the nip roll method is preferred. .
In the nip roll method, the melt extruded from the T-die is cooled by a plurality of cooling rolls (nip rolls) arranged adjacent to each other with a distance corresponding to the desired thickness of the acrylic resin film. Pressed and cooled by a roll unit.
Hereinafter, in the cooling roll unit, the n-th (n is an integer equal to or greater than 1) cooling roll from the upstream side will be referred to as the "nth cooling roll". The cooling roll unit includes at least a first cooling roll and a second cooling roll having a spaced portion below the discharge port of the T-die. The number of cooling rolls is two or more, preferably three to four.

The melt extruded from the T-die is sandwiched between the first cooling roll and the second cooling roll, pressurized and cooled to form the acrylic resin film of the present invention. The acrylic resin film produced by the above method is not sufficiently cooled only by the chill roll unit, and is usually not completely solidified even when it leaves the most downstream chill roll. After separating from the most downstream cooling roll, the acrylic resin film is further cooled while flowing down.

As described above, in the method for producing an acrylic resin film of the present invention, the first cooling roll and the second cooling roll are preferably rigid metal rolls and/or elastic metal rolls. It is preferable to sandwich the object between a pair of cooling rolls consisting of a metal rigid roll and/or a metal elastic roll. More preferably, it is an elastic roll.
By using a metal elastic roll having a smooth surface, preferably a mirror surface, both film surfaces can have high gloss at room temperature and good printability.
Non-metal rolls such as rubber rolls have lower surface smoothness than rigid metal rolls and elastic metal rolls, making it difficult to obtain a highly glossy film surface.

A metal elastic roll is a metal roll whose surface is elastically deformable during film production. The surface of the metal elastic roll is a smooth surface, preferably a mirror surface. As the metal elastic roll, a known metal elastic roll that is generally used in extrusion molding can be used. A double structure metal elastic roll is used in which a cooling fluid flows down inside the inner roll and/or between the inner roll and the outer cylinder. Rubber or any fluid not for cooling purposes may be interposed between the inner roll and the outer cylinder. The thickness of the outer cylinder is sufficiently thin so that it can be elastically deformed without breaking during film production, and is, for example, about 2 to 8 mm. The outer cylinder preferably has a seamless structure with no weld joints. Materials for the inner roll and the outer cylinder are not particularly limited, and examples thereof include stainless steel and chromium steel.

[Acrylic resin film]
The acrylic resin film of the present invention may be an unstretched film or a stretched film. As used herein, film means unstretched film unless otherwise specified.
Usually, when the thickness is 5 to 250 μm, it is mainly classified as a “film”, and when it is thicker than 250 μm, it is mainly classified as a “sheet”, but in this specification, the film and the sheet are clearly distinguished. Both are collectively referred to as a "film".

The thickness of the acrylic resin film of the present invention is not particularly limited.
The thickness of the acrylic resin film produced by the above production method is preferably 10 to 500 μm, more preferably 20 to 400 μm, even more preferably 30 to 120 μm, and particularly preferably 40 to 80 μm. be. When the thickness of the film is 10 μm or more, it becomes easy to mold. Further, when the thickness is 500 μm or less, laminating properties, handling properties, cutting properties, punching properties, and other secondary processing properties are improved, and the material cost per unit area can be suppressed.

The tensile elongation at break of the acrylic resin film of the present invention measured at a temperature of 23° C. and a tensile speed of 20 mm/min is preferably 80% or more, more preferably 85% or more, and still more preferably 90%. % or more, and more preferably 95% or more. When the tensile elongation at break is 80% or more, breakage during processing is less likely to occur, improving productivity.
The tensile elongation at break is a value measured under the above conditions according to JIS K 7127 (1999), and can be specifically measured by the method described in Examples.

The tensile strength at break of the acrylic resin film of the present invention measured at a temperature of 23° C. and a tensile speed of 20 mm/min is preferably 30 MPa or more, more preferably 33 MPa or more, and still more preferably 37 MPa or more. . When the tensile strength at break is 30 MPa or more, the film does not break in the roll rewinding process in the film forming process, and continuous productivity can be ensured.
The tensile strength at break is a value measured under the above conditions in accordance with JIS K 7127 (1999), and can be specifically measured by the method described in Examples.

The number of folding endurances of the acrylic resin film of the present invention in the longitudinal direction (MD direction) and width direction (TD direction) measured in accordance with JIS P8115 (2001) is preferably 100. times or more, more preferably 150 times or more, and still more preferably 200 times or more. When the folding endurance is 100 times or more, the film has excellent folding endurance.
Specifically, the folding endurance can be measured by the method described in Examples.

The trouser tear strength of the acrylic resin film of the present invention measured in accordance with JIS K7128-1 (1998) is preferably 1.0 N/mm or more, more preferably 1.2 N/mm or more, More preferably, it is 1.4 N/mm or more. When the trouser tear strength is 1.0 N/mm or more, the strength in the thickness direction of the film can be increased, and the handleability can be improved.
Specifically, the trouser tear strength can be measured by the method described in Examples.

The acrylic resin film of the present invention may be a stretched film. That is, the unstretched film may be stretched to form a stretched film. The stretching treatment enhances 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, and the like. The lower limit of the stretching temperature is preferably 10° C. higher than the glass transition temperature (Tg) of the (meth)acrylic resin composition (R) from the viewpoint that the film can be stretched uniformly and a high-strength film can be obtained. The upper limit of the stretching temperature is preferably 40° C. higher than the glass transition temperature (Tg) of the (meth)acrylic resin composition (R).

The acrylic resin film of the present invention may be a decorative film or a building material film. The present invention also includes a laminated film comprising various layers on at least one surface of the acrylic resin film of the present invention.

At least one surface of the acrylic resin film of the present invention may be printed (printed resin film). Usually, any one side of the acrylic resin film of the present invention is printed. Since the acrylic resin film of the present invention has excellent surface smoothness on both sides at room temperature, it is possible to suppress print defects and provide a printed resin film having a good printed appearance.
The printing method is not particularly limited, and known printing methods such as gravure printing, flexographic printing, and silk screen printing can be used.
When the printed resin film is laminated on the base material, it is preferable to laminate so that the printed surface is in contact with the base material from the viewpoint of protecting the printed surface and imparting a luxurious feeling.

<Laminated film>
The laminated film of the present invention comprises, on at least one surface of the acrylic resin film of the present invention, a film comprising a functional layer described below, and a layer comprising one or more selected from metals and metal oxides. A thermoplastic resin layer such as a film, a film having a base layer, a carbonate-based resin, a vinyl chloride-based resin, a vinylidene fluoride-based resin, a (meth)acrylic-based resin, an ABS-based resin, an AES-based resin, a PVB resin, etc. A film comprising one or two or more types may be mentioned.

Examples of the functional layer include a hard coat layer, an antiglare layer, an antireflection layer, an antisticking layer, a diffusion layer, an antiglare layer, an antistatic layer, an antifouling layer, and a slippery layer containing fine particles.

The method for producing the laminated film of the present invention is not particularly limited.
As a method for producing the laminated film of the present invention, (1) a raw material resin composition ((meth)acrylic resin composition (R)) of the acrylic resin film of the present invention and another thermoplastic resin (composition) and (2) either the raw material resin composition of the acrylic resin film of the present invention or the other thermoplastic resin (composition), which is preliminarily extruded into the film. (3) the raw material resin composition of the acrylic resin film of the present invention, and another thermoplastic resin ( (4) A film obtained by obtaining a film in advance for the raw material resin composition of the acrylic resin film of the present invention. A method of polymerizing the polymerizable composition above to produce a laminated film, and the like.

By printing the exposed surface of the acrylic resin film of the present invention on the laminated film obtained by the above methods (1) to (4), a laminated film containing a printed resin film can be obtained. .

Moreover, the acrylic resin film of the present invention can be laminated on a substrate to form a laminate. By laminating the acrylic resin film of the present invention on a substrate, the design of the substrate can be improved. Moreover, the effect of substrate protection is also acquired.

The material of the substrate is not particularly limited, and examples thereof include resins, steel materials, wood, glass, composite materials thereof, and the like. The resin used for the substrate is not particularly limited, and thermoplastic resins and thermosetting resins can be used. Examples of thermoplastic resins used for the base material include carbonate-based resins, ethylene terephthalate-based resins, amide-based resins, olefin-based resins, styrene-based resins, vinyl chloride-based resins, (meth)acrylic-based resins, and ABS-based resins. mentioned. Thermosetting resins used for the substrate include epoxy-based resins, phenol-based resins, melamine-based resins, and the like.
The method for manufacturing the laminate in which the acrylic resin film of the present invention is laminated is not particularly limited, and examples thereof include adhesion, lamination, insert molding, and in-mold molding.

When the material of the base material is a resin, a method of vacuum forming, pressure forming, or compression forming the acrylic resin film or the like of the present invention on the surface of the base material under heating is preferable. Among them, the injection molding simultaneous lamination method is particularly preferable. In the injection molding simultaneous lamination method, after inserting the acrylic resin film of the present invention between a pair of male and female molds for injection molding, a molten thermoplastic resin is injected into the mold (on one side of the film). It is a method of molding. In this method, the production of the injection-molded article and the lamination of the film can be carried out at the same time.

The film to be inserted into the mold may be a flat film or may be a film having an uneven shape obtained by preforming such as vacuum forming or pressure forming. Preforming of the film may be performed in a separate molding machine, or may be performed in the mold of an injection molding machine used for the simultaneous injection molding lamination method. A method of injecting molten resin onto one surface of a film after preforming is called an insert molding method.
When the material of the substrate is a resin, there is also a method of co-extrusion molding the substrate and the film to be laminated.

Furthermore, it is also possible to apply a coating layer on the acrylic resin film of the present invention laminated on a base material, which is cured by irradiation with ultraviolet rays (UV) or electron beams (EB). In this case, it is possible to further enhance the design property or substrate protection property.

Applications of the acrylic resin film and laminated film of the present invention are not particularly limited, and they can be preferably used in various applications that require designability, such as decorative applications, building material applications, and the like.
Specific applications include interior parts such as furniture, pendant lights, and mirrors; architectural parts such as doors, domes, safety window glass, partitions, stair wainscots, balcony wainscots, and roofs of leisure buildings. be done.
Other uses include billboard parts or marking films for advertising towers, stand signs, sleeve signs, transom signs, and rooftop signs; display parts such as showcases, partitions, and store displays; fluorescent lamp covers, mood lighting covers. Lighting parts such as lampshades, light ceilings, light walls, and chandeliers; aircraft windshields, pilot visors, motorcycle windshields, motorboat windshields, shading plates for buses, side visors for automobiles, rear visors, head wings, headlight covers, automobiles Parts related to transportation equipment such as interior parts and automobile exterior parts such as bumpers; audiovisual nameplates, stereo covers, TV protective masks, electronic equipment parts such as vending machines, mobile phones, and personal computers; incubators and X-ray parts medical device parts such as; machine covers, instrument covers, laboratory equipment, rulers, dials, and observation windows; Household appliances; Traffic-related parts such as road signs, information boards, curved mirrors, and soundproof walls; and a decorative film/protective film provided on the surface of a mask for protecting the face during welding.

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. The physical property values and the like in Examples and Comparative Examples were measured by the following methods.

[Average particle size of acrylic multilayer structure polymer particles (A) in latex state]
The latex of the acrylic multilayer structure polymer particles (A) obtained in Production Example 1 was sampled and measured by a light scattering method using a laser diffraction/scattering particle size distribution analyzer LA-300 manufactured by Horiba, Ltd. The average particle size was determined by

[Average particle diameter of acrylic multilayer structure polymer particles (A) in acrylic resin film (average particle diameter of acrylic multilayer structure polymer particles (A) observed by TEM)]
Using a transmission electron microscope (TEM; manufactured by JEOL, model number: JSM-7600), the acrylic resin film was photographed at an acceleration voltage of 25 kV and a magnification of 100,000 times. The particle size of 100 acrylic multilayer structure polymer particles (A) was measured from the obtained cross-sectional image, and the average particle size was calculated.

[Average degree of polymerization]
Using an automatic viscosity measuring device (manufactured by Shibayama Kagaku Kikai Seisakusho, model number: SS-405-L1), measurement was performed under the conditions of chloroform solvent and measurement temperature of 20°C.

[Limiting viscosity]
In water at 20 ° C., the specific viscosity (η _SP ) is measured with an Ubbelohde viscometer (manufactured by Shibayama Scientific Instruments Manufacturing Co., Ltd., model number: SS-405-L1), and the following formula (1) (Huggins formula) is used. to calculate the intrinsic viscosity [η].

η_ＳＰ（ｄＬ／ｇ）：比粘度
［η］（ｄＬ／ｇ）：極限粘度
Ｃ（ｇ／ｄＬ）：ポリマー粘度
Ｋ：ハギンス定数

η _SP (dL/g): Specific viscosity [η] (dL/g): Intrinsic viscosity C (g/dL): Polymer viscosity K: Huggins constant

[Weight average molecular weight (Mw)]
The weight average molecular weight (Mw) was determined by GPC (gel permeation chromatography) as a standard polystyrene equivalent molecular weight. The measuring equipment and conditions are as follows.
・ Apparatus: GPC apparatus "HLC-8320" manufactured by Tosoh Corporation
・ Separation column: Direct connection of “TSKgel SuperMultipore HZM-M” and “SuperHZ4000” manufactured by Tosoh Corporation ・ Detector: “RI-8020” manufactured by Tosoh Corporation
・Eluent: tetrahydrofuran ・Eluent flow rate: 0.35 mL/min ・Sample concentration: 8 mg/10 mL
・Column temperature: 40°C

[Tensile breaking strength and tensile breaking elongation]
According to JIS K7127 (1999), the central part of the acrylic resin film prepared in Examples and Comparative Examples was punched out using a mold into a test piece type 1B shape, at a temperature of 23 ° C., and a tensile speed of 200 mm / min. , the tensile strength at break and tensile elongation at break were measured.

[Folding endurance test (number of folding endurance)]
A test piece was taken from the central part of the acrylic resin film produced in Examples and Comparative Examples, and measured by a method based on JIS P8115 (2001).

[Trouser tearing strength]
A test piece was taken from the central part of the acrylic resin film produced in Examples and Comparative Examples, and measured by a method according to JIS K7128-1 (1998).

[Film formability]
Using a 65 mmΦ vented single-screw extruder, extruding the (meth)acrylic resin composition (R) at an extrusion temperature of 260° C. from a die with a width of 400 mm (lip opening of 0.8 mm) at a discharge rate of 20 kg / h, It was sandwiched between a 60° C. metal mirror-surface elastic roll and a 65° C. metal mirror-surface rigid roll, and was drawn off at a line speed of 20 m/min to form a film having a thickness of 50 μm. At this time, the variation coefficient of the film thickness due to neck-in at both ends of the melt curtain pulled down from the die was evaluated. In addition, if it is A or B in the following evaluation criteria, it can be put to practical use. The coefficient of variation in film thickness is obtained by measuring the thickness at 20 points in total at intervals of 5 mm in the direction of flow of the film with a micrometer (manufactured by Mitutoyo, model number: MDH-25), and the variation in thickness is the coefficient of variation (%). It was calculated as (standard deviation/mean x 100).
A: Variation coefficient of 0% or more and less than 1% B: Variation coefficient of 1% or more and less than 3% C: Variation coefficient of 3% or more

(Production Example 1: Polymerization of acrylic multilayer structure polymer particles (A))
(1) 200 parts by mass of deionized water, 1 part by mass of sodium dodecylbenzenesulfonate and 0 part of sodium carbonate are placed in a reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet, a monomer inlet tube and a reflux condenser. 0.05 part by mass was charged, and the inside of the container was sufficiently replaced with nitrogen gas to make it substantially oxygen-free, and then the internal temperature was set to 80°C. 0.01 parts by mass of potassium persulfate was added thereto, and after stirring for 5 minutes, 9.48 parts by mass of methyl methacrylate, 0.5 parts by mass of n-butyl acrylate and 0.02 parts by mass of allyl methacrylate The monomer mixture was continuously added dropwise over a period of 20 minutes, and after completion of the addition, the polymerization reaction was continued for an additional 30 minutes so that the polymerization rate was 98% or higher.

(2) Next, 0.03 parts by mass of potassium persulfate was charged into the reactor and stirred for 5 minutes, followed by 1.45 parts by mass of methyl methacrylate, 27.67 parts by mass of n-butyl acrylate and methacrylic acid. A monomer mixture containing 0.88 parts by mass of allyl acid was continuously added dropwise over 40 minutes. After the completion of the addition, the polymerization reaction was further carried out for 30 minutes so that the polymerization rate was 98% or higher.

(3) Next, 0.06 parts by mass of potassium persulfate was charged into the same reactor and stirred for 5 minutes, followed by 53.73 parts by mass of methyl methacrylate, 5.97 parts by mass of n-butyl acrylate, and A monomer mixture containing 0.3 parts by mass of n-octyl mercaptan (chain transfer agent) was continuously added dropwise over 100 minutes. A reaction was carried out to obtain a latex containing acrylic multilayer structure polymer particles (A). The average particle size in the latex state was 100 nm.
Subsequently, the latex containing the acrylic multilayer structure polymer particles (A) was frozen at −30° C. for 4 hours. The frozen latex was added to twice the amount of hot water at 80°C, dissolved to form a slurry, held at 80°C for 20 minutes, dehydrated, and dried at 70°C to obtain acrylic multilayer structure polymer particles (A). got

(Production Example 2: Polymerization of methacrylic resin (C))
94 parts by mass of methyl methacrylate and 6 parts by mass of methyl acrylate, polymerization initiator (2,2′-azobis(2-methylpropionitrile), hydrogen abstraction capacity: 1%, 1-hour half-life temperature: 83° C.) 0 1 part by mass and 0.18 part by mass of a chain transfer agent (n-octyl mercaptan) were added and dissolved to obtain a raw material liquid. A liquid 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 to give a bead-like methacrylic A resin (C) was obtained. The obtained methacrylic resin (C) had a methyl methacrylate monomer unit content of 94% by mass, a methyl acrylate monomer unit content of 6% by mass, and an average degree of polymerization of 1,605. , a weight average molecular weight (Mw) of 130,000, an intrinsic viscosity of 0.72 dL/g, and an MFR of 1.3 g/10 min.

The following polymer processing aids and UV absorbers were used.
[Polymer Processing Aid (B)]
- Polymer processing aid (B1): Mitsubishi Chemical Corporation, Metabrene (registered trademark) P530A
(Average degree of polymerization: 24,455, content of methyl methacrylate monomer unit is 80% by mass, content of butyl acrylate monomer unit is 20% by mass)
- Polymer processing aid (B2): manufactured by Mitsubishi Chemical Corporation, Metabrene (registered trademark) P531A
(Average degree of polymerization: 37,162, content of methyl methacrylate monomer unit is 80% by mass, content of butyl acrylate monomer unit is 20% by mass)

[Polymer processing aid having an average degree of polymerization of less than 20,000]
・Polymer processing aid (D1): Paraloid K125P manufactured by Dow Chemical Co.
(Average degree of polymerization: 19,874, content of methyl methacrylate monomer units is 79% by mass, content of butyl acrylate monomer units is 21% by mass)
・Polymer processing aid (D2): Mitsubishi Chemical Corporation, Metabrene (registered trademark) P550A
(Average degree of polymerization: 7,734, content of methyl methacrylate monomer unit is 88% by mass, content of butyl acrylate monomer unit is 12% by mass)

[Ultraviolet absorber]
・Ultraviolet absorber: ADEKA Co., Ltd., Adekastab LA-31RG

[Example 1]
90 parts by mass of the acrylic multilayer structure polymer particles (A) obtained in Production Example 1, 10 parts by mass of the methacrylic resin (C) obtained in Production Example 2, 2 parts by mass of the polymer processing aid (B1), and 2 parts by mass of the ultraviolet absorber was added to the hopper of a 41 mmφ twin-screw kneading extruder (manufactured by Toshiba Machine Co., Ltd., TEM41-SS) while controlling it with a weight feeder, and the temperature under the hopper was 150 ° C., other barrels, The die temperature is set to 230° C., the (meth)acrylic resin composition (R) is extruded into strands, and cut with a pelletizer to produce pellets of the (meth)acrylic resin composition (R). bottom.
The obtained pellets are extruded at a discharge rate of 20 kg / h from a die (lip opening of 0.8 mm) with a width of 400 mm at an extrusion temperature of 260 ° C. using a vented single screw extruder of 65 mmφ, and extruded on a mirror surface at 60 ° C. It was sandwiched between an elastic metal roll and a rigid metal roll having a mirror surface at 65° C., and was drawn off at a line speed of 20 m/min to form a film having a thickness of 50 μm. The average particle size of the acrylic multilayer structure polymer particles (A) in the resulting film was 80 nm. In addition, Table 1 shows the evaluation results of the film.

[Examples 2 to 7]
A (meth)acrylic resin composition (R) and a film were obtained in the same manner as in Example 1, except that the formulation shown in Table 1 was used. Table 1 shows the evaluation results.

[Comparative Examples 1 to 3]
A (meth)acrylic resin composition and a film were obtained in the same manner as in Example 1, except that the formulation shown in Table 1 was used. Table 1 shows the evaluation results. When the polymer processing aids (D1) and (D2) having an average degree of polymerization of less than 20,000 were used, the tensile elongation at break was inferior (Comparative Examples 1 and 2). Moreover, when the polymer processing aid was not used, the result was that the film formability was insufficient (Comparative Example 3).

Claims (10)

An acrylic resin film made of a (meth)acrylic resin composition (R) containing acrylic multilayer structure polymer particles (A), a polymer processing aid (B), and a methacrylic resin (C). hand,
The acrylic multilayer structure polymer particles (A) include a first layer composed of a crosslinked resin layer containing 30 to 98.99% by mass of methyl methacrylate monomer units from the center side, and 70 to 99.9% by mass of the first layer. A second layer comprising a crosslinked resin layer containing 70 to 100% by mass of methacrylic acid alkyl ester monomer units in which the alkyl group has 1 to 8 carbon atoms. The acrylic multilayer structure polymer particles (A) have an average particle diameter of 10 to 200 nm as measured by TEM observation, and the ( The content of the acrylic multilayer structure polymer particles (A) with respect to the total amount of the meth)acrylic resin composition (R) is 60% by mass or more,
The polymer processing aid (B) comprises 60% by mass or more of methyl methacrylate monomer units and 40% by mass or less of vinyl monomer units, and has an average degree of polymerization of the polymer processing aid (B). is 20,000 or more, and the content of the polymer processing aid (B) with respect to the total amount of the (meth)acrylic resin composition (R) is 0.1 to 7% by mass,
The methacrylic resin (C) contains 80% by mass or more of methyl methacrylate monomer units, the intrinsic viscosity of the methacrylic resin (C) is 0.4 to 1.0 dL / g, and the (methacrylic ) An acrylic resin film in which the content of the methacrylic resin (C) is 1 to 35% by mass relative to the total amount of the acrylic resin composition (R) . The acrylic resin according to claim 1, which has a tensile elongation at break of 80% or more measured under conditions of a temperature of 23°C and a tensile speed of 20 mm/min, and a tensile strength at break of 30 MPa or more measured under the conditions. the film. 3. The number of folds in the longitudinal direction (MD direction) and the width direction (TD direction) of the acrylic resin film measured according to JIS P8115 (2001) is 100 times or more. acrylic resin film. 4. The acrylic resin film according to any one of claims 1 to 3, which has a trouser tear strength of 1.0 N/mm or more as measured according to JIS K7128-1 (1998). The acrylic resin film according to any one of claims 1 to 4 , wherein the (meth)acrylic resin composition (R) further contains a benzotriazole ultraviolet absorber. 6. The acrylic resin film according to any one of claims 1 to 5 , which is printed on at least one surface. The acrylic resin film according to any one of claims 1 to 5 , which is a decorative film. The acrylic resin film according to any one of claims 1 to 5 , which is a film for building materials. At least one surface of the acrylic resin film according to any one of claims 1 to 8 is provided with a layer made of one or more selected from metals and metal oxides, a thermoplastic resin layer, or a base layer. laminated film. A step of melt extruding the (meth)acrylic resin composition (R) from a T-die into a film, and a pair of cooling rolls consisting of a rigid metal roll and/or an elastic metal roll for extruding the melt extruded from the T-die. The method for producing an acrylic resin film according to any one of claims 1 to 8 , comprising a step of sandwiching with.