JP7790212B2 - Acrylic resin composition, film, and method for producing film - Google Patents

Description

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

Acrylic resin films are widely used in a variety of fields, including building materials such as roofing materials and siding materials, as well as covering materials for automobile interiors and exteriors and furniture. Patent Document 1 discloses the formation of a film from an acrylic resin composition containing a rubber-containing multistage polymer consisting of a graft polymer having an elastic polymer and a rigid polymer.

International Publication No. 2015/156323

Films made using rubber-containing multistage polymers such as those described in Patent Document 1 have sufficient flexibility as the ratio of rigid polymers decreases, but they tend to stick to rolls in the film-forming machine, such as cooling rolls, during film production. This makes the film more susceptible to breakage and surface defects when peeled from the roll surface. On the other hand, a higher ratio of rigid polymers reduces flexibility and makes the film more susceptible to whitening during bending. As such, with films made from conventional acrylic resin compositions such as those described in Patent Document 1, it is difficult to simultaneously prevent whitening during bending and prevent sticking to rolls.

The present invention aims to provide an acrylic resin composition that can simultaneously suppress whitening during bending and sticking to rolls, as well as a film using the acrylic resin composition and a method for producing the film.

The present invention has the following aspects.
[1] An acrylic resin composition containing a core-shell rubber (A) and crosslinked particles (B),
the average particle size of the crosslinked particles (B) is 0.1 to 10 μm,
The core-shell rubber (A) comprises a core having a glass transition temperature of 0°C or lower and a shell having a glass transition temperature of higher than 20°C, and has a graft ratio of 40% or lower.
[2] The acrylic resin composition according to [1], wherein the tensile modulus measured in accordance with ISO 527:2012 on a test piece having a thickness of 50 μm and a width of 15 mm under the conditions of a temperature of 23°C, a pulling rate of 100 mm/min, and a chuck distance of 100 mm is 1000 MPa or less.
[3] An acrylic resin composition containing crosslinked particles (B),
the average particle size of the crosslinked particles (B) is 0.1 to 10 μm,
An acrylic resin composition having a tensile modulus of 1000 MPa or less, measured in accordance with ISO 527:2012 using a test piece having a thickness of 50 μm and a width of 15 mm at a temperature of 23°C, a pulling rate of 100 mm/min, and a chuck distance of 100 mm.
[4] The acrylic resin composition according to any one of [1] to [3], wherein the content of the crosslinked particles (B) is 0.001 to 1 mass%.
[5] A film having at least an acrylic resin layer made of the acrylic resin composition according to any one of [1] to [4].
[6] The film according to [5], wherein the acrylic resin layer and a fluororesin layer made of a fluororesin composition are laminated together.
[7] A method for producing a film, comprising a step of forming the acrylic resin composition according to any one of [1] to [4] into a film.
[8] The manufacturing method according to [7], further comprising a step of sandwiching the formed film between two rolls.
[9] The manufacturing method according to [8], wherein at least one of the two rolls is a mirror-finished metal roll.

The present invention provides an acrylic resin composition that can simultaneously suppress whitening due to bending and sticking to rolls, as well as a film using the acrylic resin composition and a method for producing the film.

In the present invention, the term "monomer" means a compound having a polymerizable carbon-carbon double bond.
The term "monomer unit" refers to a constituent unit based on a monomer that is formed by polymerizing one molecule of the monomer.
"(Meth)acrylic acid" refers to acrylic acid or methacrylic acid.

[Acrylic resin composition]
An example of the acrylic resin composition of the present invention will be described below.
First Embodiment
The acrylic resin composition of the first embodiment is an acrylic resin composition containing a core-shell rubber (A) and crosslinked particles (B).

(Core-shell rubber (A))
The core-shell rubber (A) is a rubber having a multilayer structure containing a core part (hereinafter also referred to as "core part (A1)") having a glass transition temperature (hereinafter also referred to as "Tg") of 0°C or lower and a shell part (hereinafter also referred to as "shell part (A2)") having a Tg of higher than 20°C.
The Tg of the core part (A1) is preferably −60° C. or higher, and is preferably −10° C. or lower.
The Tg of the shell part (A2) is preferably 40°C or higher, and is preferably 120°C or lower.

The Tg is a value measured by the following method. First, an acrylic resin composition is melted and formed into a sheet, and a test piece having dimensions of 1 mm in thickness, 6 mm in width, and 65 mm in length is cut out. Using a dynamic viscoelasticity measuring device in accordance with ISO 6721-4, the storage modulus (E') and loss modulus (E") of the test piece are measured in a tensile mode under the conditions of an initial chuck distance of 2 cm, a measurement frequency of 0.1 Hz, a measurement temperature range of −90 to 150°C, a heating rate of 2°C/min, and a nitrogen gas flow of 200 mL/min, and tan δ (loss tangent) at each temperature is calculated from the formula tan δ = E"/E'. Next, when the tan δ values are plotted against temperature, two or more peaks appear. The temperature corresponding to the peak that appears on the lowest temperature side among these peaks is defined as the Tg of the core portion (A1). Furthermore, among the peaks that appear at temperatures higher than 20°C, the temperature corresponding to the peak with the largest tan δ value is defined as the Tg of the shell portion (A2). The shell portion is preferably the outermost layer of the core-shell rubber.
The core-shell rubber (A) may contain an intermediate portion (A3) having a Tg of more than 0° C. and not more than 20° C. between the core portion (A1) and the shell portion (A2). Furthermore, the core-shell rubber (A) may contain an innermost portion (A4) having a Tg of more than 0° C. inside the core portion (A1). The Tg of the innermost portion (A4) is lower than the Tg of the shell portion (A2).

The content (core ratio) of the core portion (A1) in the core-shell rubber (A) is preferably 40% by mass or more, and preferably 80% by mass or less, relative to the total mass of the core-shell rubber (A). When the content of the core portion (A1) is at least the above-mentioned lower limit, the mechanical strength and flexibility of the film are improved, and breakage, cracking, and whitening during molding and bending are more easily suppressed. When the content of the core portion (A1) is at most the above-mentioned upper limit, the film is less likely to stick to the roll surface during film production.

The content of the shell portion (A2) in the core-shell rubber (A) is preferably 20% by mass or more, and preferably 60% by mass or less, based on the total mass of the core-shell rubber (A). If the content of the shell portion (A2) is equal to or greater than the lower limit, the film is less likely to stick to the roll surface during film production. If the content of the shell portion (A2) is equal to or less than the upper limit, the film is less likely to whiten even when subjected to bending processing.

The content of the intermediate portion (A3) in the core-shell rubber (A) may be 0% by mass, and is preferably 5% by mass or more, and is preferably 20% by mass or less, and more preferably 15% by mass or less, relative to the total mass of the core-shell rubber (A).
The content of the innermost part (A4) in the core-shell rubber (A) is preferably 10% by mass or less based on the total mass of the core-shell rubber (A). The lower limit of the content of the innermost part (A4) is not particularly limited, and may be 0% by mass.

The core-shell rubber (A) is preferably a rubber consisting of a core portion (A1) and a shell portion (A2), or a rubber consisting of a core portion (A1), an intermediate portion (A3) and a shell portion (A2).
The core-shell rubber (A) consisting of a core part (A1) and a shell part (A2) is preferably a rubber having a core part (A1) of 40 to 80% by mass and a shell part (A2) of 20 to 60% by mass (total of 100% by mass).
The core-shell rubber (A) consisting of a core portion (A1), an intermediate portion (A3), and a shell portion (A2) is preferably a rubber having a core portion (A1) of 40 to 75% by mass, an intermediate portion (A3) of 5 to 15% by mass, and a shell portion (A2) of 20 to 55% by mass (total of 100% by mass).

The graft ratio of the core-shell rubber (A) is 40% or less, preferably 35% or less, more preferably 30% or less, and even more preferably 25% or less, while it is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more. When the graft ratio of the core-shell rubber (A) is the upper limit or less, the flexibility of the film is improved and whitening during bending is suppressed. In addition, the flowability is improved and the film thickness stability during production is excellent. When the graft ratio of the core-shell rubber (A) is the lower limit or more, it is easy to suppress sticking to the roll during production of the film.
The graft ratio of the core-shell rubber (A) is the ratio (percentage) of the mass of the component grafted to the layer located inside the shell portion (A2) to the total mass of the core portion (A1), intermediate portion (A3), and innermost portion (A4), and is calculated by the following formula:
Graft rate (%) = 100 × (mass of acetone insoluble matter in core-shell rubber (A) - mass of core portion (A1) - mass of middle portion (A3) - mass of innermost portion (A4)) / (mass of core portion (A1) + mass of middle portion (A3) + mass of innermost portion (A4))

The mass average molecular weight of the acetone soluble portion of the core-shell rubber (A) is preferably 25,000 or more, more preferably 30,000 or more, and is preferably 70,000 or less, more preferably 50,000 or less. When the mass average molecular weight of the acetone soluble portion of the core-shell rubber (A) is at or above the lower limit, the mechanical strength of the film is improved and cracking is easily suppressed. Furthermore, breakage and whitening during molding and bending are easily suppressed. When the mass average molecular weight of the acetone soluble portion of the core-shell rubber (A) is at or below the upper limit, the fluidity of the resulting resin composition is improved, resulting in excellent processability during melt molding. Furthermore, the surface smoothness of the film obtained by melt molding is improved, resulting in a good appearance.

The mass average molecular weight of the acetone-soluble portion of the core-shell rubber (A) is a value measured by gel permeation chromatography (GPC) on the acetone-soluble portion obtained by dissolving 1 g of core-shell rubber (A) in 50 g of acetone and refluxing at 70°C for 4 hours. The mass average molecular weight of the acetone-soluble portion of the core-shell rubber (A) can be adjusted by appropriately changing the amount of chain transfer agent used during polymerization.

The polymerization method for the core-shell rubber (A) is not particularly limited, and examples thereof include emulsion polymerization and suspension polymerization. In the case of emulsion polymerization, it is preferable to use an emulsifier, a radical polymerization initiator, and a chain transfer agent.
Examples of emulsifiers include anionic surfactants, cationic surfactants, and nonionic surfactants, with anionic surfactants being preferred. Examples of anionic surfactants include, but are not limited to, carboxylates (rosin acid soap, potassium oleate, sodium stearate, etc.), sulfates (sodium lauryl sulfate, etc.), sulfonates (sodium dioctyl sulfosuccinate, etc.), and phosphates (sodium polyoxyethylene alkylphenyl ether phosphate, etc.). One or more types of emulsifiers may be used.

The radical polymerization initiator is not particularly limited, and examples include persulfates (potassium persulfate, sodium persulfate, etc.), organic peroxides (t-butyl hydroperoxide, etc.), azo compounds (azobisisobutyronitrile, etc.), and redox initiators that combine persulfates or organic peroxides with a reducing agent. Of these, redox initiators are preferred. One or more types of radical polymerization initiators may be used.

The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans having 2 to 20 carbon atoms, mercapto acids, thiophenol, and carbon tetrachloride. One type of chain transfer agent may be used, or two or more types may be used.
The amount of the chain transfer agent used is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the total amount of the monomers, while it is preferably 1.5 parts by mass or less, more preferably 1.0 part by mass or less, and even more preferably 0.5 parts by mass or less. When the amount of the chain transfer agent used is the lower limit or more, the flexibility of the film is improved. When the amount of the chain transfer agent used is the upper limit or less, the mechanical strength of the film is improved.

The polymerization for forming the core portion (A1) may be in one stage or in two or more stages. The polymerization for forming the shell portion (A2), intermediate portion (A3), and innermost portion (A4) may also be in one stage or in two or more stages.

The polymerization temperature varies depending on the type and amount of polymerization initiator, but is preferably 40°C or higher, more preferably 60°C or higher, while it is preferably 120°C or lower, more preferably 95°C or lower.

The content of core-shell rubber (A) in the acrylic resin composition is preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, relative to the total mass of the acrylic resin composition. On the other hand, it is preferably 99.899% by mass or less, more preferably 99.89% by mass or less, and even more preferably 99.78% by mass or less. When the content of core-shell rubber (A) is at least the lower limit, the flexibility of the film is improved, and whitening during bending and other processes is easily suppressed. When the content of core-shell rubber (A) is at most the upper limit, sticking to rolls during film production is easily suppressed.

In the present invention, an acrylic resin composition means a composition that contains at least an acrylic core-shell rubber.

(Acrylic core-shell rubber (AA))
The acrylic core-shell rubber is a rubber with a multilayer structure containing a core portion (hereinafter also referred to as "core portion (AA1)") having a glass transition temperature (hereinafter also referred to as "Tg") of 0°C or lower and a shell portion (hereinafter also referred to as "shell portion (AA2)") having a Tg of higher than 20°C.
The core part (AA1) may be, for example, a polymer obtained by polymerizing a monomer composition containing a (meth)acrylic acid alkyl ester and a grafting agent. The Tg is measured in the same manner as for the core-shell rubber (A) described above.
The alkyl group of the (meth)acrylic acid alkyl ester may be linear or branched. As the (meth)acrylic acid alkyl ester, an acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms (hereinafter also referred to as "monomer (a11)") and a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms (hereinafter also referred to as "monomer (a12)") are preferred.

Examples of monomer (a11) include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and n-octyl acrylate. Among these, alkyl acrylate esters with low Tg are preferred, and n-butyl acrylate is more preferred, in terms of providing excellent impact resistance to the core portion (AA1) and ease of molding. Monomer (a11) used for the core portion (AA1) may be one type or two or more types.

Examples of the monomer (a12) include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. The monomer (a12) used in the core part (AA1) may be one type or two or more types.
Either the monomer (a11) or the monomer (a12) may be used alone, or both of them may be used together.

In addition to monomer (a11) and monomer (a12), the core portion (AA1) may further contain a monomer having one polymerizable carbon-carbon double bond (hereinafter also referred to as "monomer (a13)"). Examples of monomer (a13) include higher alkyl acrylates having an alkyl group with 9 or more carbon atoms, lower alkoxyalkyl acrylates having an alkoxyalkyl group with 8 or less carbon atoms, alkyl acrylates such as cyanoethyl acrylate, acrylamide, acrylic acid, methacrylic acid, styrene, alkyl-substituted styrene, acrylonitrile, and methacrylonitrile. The monomer (a13) used in the core portion (AA1) may be one type or two or more types.

The graft crosslinking agent imparts rubber elasticity to the core portion (AA1) through a crosslinking reaction, and also crosslinks the core portion (AA1) and shell portion (AA2) through a graft crosslinking reaction. Specifically, the conjugated unsaturated bonds of the ester of the graft crosslinking agent react faster than the allyl, methallyl, or crotyl groups, forming chemical bonds. Meanwhile, most of the allyl, methallyl, or crotyl groups in the graft crosslinking agent remain unreacted and react during the polymerization that forms the shell portion (AA2), forming graft bonds between the core portion (AA1) and shell portion (AA2).

Examples of grafting agents include allyl esters, methallyl esters, or crotyl esters of copolymerizable α,β-unsaturated carboxylic acids, and allyl esters, methallyl esters, or crotyl esters of dicarboxylic acids. Triallyl cyanurate and triallyl isocyanurate can also be used as grafting agents. Among these, allyl acrylate, allyl methacrylate, allyl maleate, and allyl fumarate are preferred, with allyl methacrylate being more preferred.

The core portion (AA1) may contain a crosslinkable monomer other than the graft crosslinking agent (hereinafter also referred to as "crosslinkable monomer (a14)"). The use of the crosslinkable monomer (a14) can impart further rubber elasticity to the core portion (AA1).
Examples of the crosslinkable monomer (a14) include alkylene glycol dimethacrylates such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, and propylene glycol dimethacrylate, and polyvinylbenzenes such as divinylbenzene and trivinylbenzene. The crosslinkable monomer (a14) may be one type or two or more types.

The amount of the monomer (a11) used is preferably 50% by mass or more, more preferably 80% by mass or more, based on the total mass of the monomer (a11) and the monomer (a12) used in the core part (AA1). The upper limit of the amount of the monomer (a11) used is not particularly limited, and may be 100% by mass.
The total amount of the monomer (a11) and the monomer (a12) used is preferably 80% by mass or more, more preferably 95% by mass or more, based on the total mass of the monomers used in the core part (AA1), and is preferably 98.7% by mass or less, more preferably 98.4% by mass or less.

The amount of graft crosslinking agent used is preferably 1.3% by mass or more, more preferably 1.6% by mass or more, and preferably 6.0% by mass or less, relative to the total mass of the monomers used in the core portion (AA1). When the amount of graft crosslinking agent used is equal to or greater than the lower limit, the crosslinking between the core portion (AA1) and the shell portion (AA2) is stabilized, making it easier to achieve sufficient transparency. Furthermore, rubber elasticity is improved, and the impact resistance of the resulting film is improved. When the amount of graft crosslinking agent used is equal to or less than the upper limit, the core portion (AA1) has appropriate flexibility, improving film handleability. Furthermore, the fluidity of the acrylic resin composition is increased, improving moldability.

The amount of the monomer (a13) used is preferably 18.7% by mass or less, more preferably 18.4% by mass or less, based on the total mass of the monomers used in the core portion (AA1). The lower limit of the amount of the monomer (a13) used is not particularly limited, and may be 0% by mass.
The amount of the crosslinkable monomer (a14) used is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total mass of the monomers used in the core portion (AA1). The lower limit of the amount of the crosslinkable monomer (a14) used is not particularly limited, and may be 0% by mass.

The shell portion (AA2) of the acrylic core-shell rubber (AA) can be exemplified by a polymer obtained by polymerizing a monomer composition containing an alkyl methacrylate ester.
As the alkyl methacrylate ester, an alkyl methacrylate ester having an alkyl group having 1 to 4 carbon atoms (hereinafter also referred to as "monomer (a21)") is preferred. Examples of the monomer (a21) include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. The monomer (a21) used in the shell portion (AA2) may be one type or two or more types.

The shell part (AA2) may further contain a monomer other than the monomer (a21) (hereinafter also referred to as "monomer (a22)").
Examples of the monomer (a22) include the same monomers as the monomer (a11) and the monomer (a13) of the core part (AA1). The monomer (a22) used in the shell part (AA2) may be one type or two or more types.

The amount of the monomer (a21) used is preferably 70% by mass or more, more preferably 85% by mass or more, based on the total mass of the monomers used in the shell portion (AA2). If the amount of the monomer (a21) used is equal to or greater than the lower limit, the Tg of the shell portion (AA2) is easily increased. The upper limit of the amount of the monomer (a21) used is not particularly limited, and may be 100% by mass.
The amount of the monomer (a22) used is preferably 30% by mass or less, more preferably 15% by mass or less, based on the total mass of the monomers used in the shell portion (AA2). The lower limit of the amount of the monomer (a22) used is not particularly limited, and may be 0% by mass.

The acrylic core-shell rubber (AA) may contain an intermediate portion (AA3) having a Tg of more than 0° C. and not more than 20° C. between the core portion (AA1) and the shell portion (AA2).
Examples of the monomer used in the intermediate portion (AA3) include an alkyl acrylate ester having an alkyl group of 1 to 8 carbon atoms (hereinafter also referred to as "monomer (a31)") and an alkyl methacrylate ester having an alkyl group of 1 to 4 carbon atoms (hereinafter also referred to as "monomer (a32)"). In addition to the monomer (a31) and the monomer (a32), the intermediate portion (A3) may also include a monomer having one polymerizable carbon-carbon double bond (hereinafter also referred to as "monomer (a33)") and a crosslinkable monomer (a34).

Examples of the monomers (a31) to (a34) include the same monomers as the monomers (a11) to (a14), respectively.
With regard to the amount of each monomer used in the intermediate part (A3), it is preferable that the amount of the monomer (a31) used is 10 to 90 mass%, the amount of the monomer (a32) used is 10 to 90 mass%, the amount of the monomer (a33) used is 0 to 20 mass%, and the amount of the crosslinkable monomer (a34) used is 0 to 10 mass%, relative to the total mass of the monomers used in the intermediate part (A3).

The acrylic core-shell rubber (AA) may contain, inside the core portion (AA1), an innermost portion (AA4) having a Tg exceeding 0° C. The Tg of the innermost portion (AA4) is lower than the Tg of the shell portion (AA2).
Examples of the monomer used in the innermost portion (AA4) include an alkyl acrylate ester having an alkyl group with 1 to 8 carbon atoms (hereinafter also referred to as "monomer (a41)") and an alkyl methacrylate ester having an alkyl group with 1 to 4 carbon atoms (hereinafter also referred to as "monomer (a42)"). In addition to the monomer (a41) and the monomer (a42), the innermost portion (AA4) may also contain a monomer having one polymerizable carbon-carbon double bond (hereinafter also referred to as "monomer (a43)") and a crosslinkable monomer (a44).

Examples of the monomers (a41) to (a44) include the same monomers as the monomers (a11) to (a14), respectively.
The amounts of the monomers used in the innermost part (AA4) are preferably 10 to 50 mass% for the monomer (a41), 20 to 70 mass% for the monomer (a42), 0 to 10 mass% for the monomer (a43), and 0.1 to 10 mass% for the crosslinkable monomer (a44), relative to the total mass of the monomers used in the innermost part (AA4).

The graft ratio of the acrylic core-shell rubber (AA) is preferably in the same range as that of the core-shell rubber (A) described above, and is, for example, preferably 40% or less and preferably 10% or more.
The mass average molecular weight of the acetone soluble portion of the acrylic core-shell rubber (AA) is preferably in the same range as that of the core-shell rubber (A) described above, for example, preferably 25,000 or more and 70,000 or less.

The content of the acrylic core-shell rubber (AA) in the acrylic resin composition is preferably in the same range as that of the core-shell rubber (A) described above, and is, for example, preferably 70% by mass or more and 99.899% by mass or less, relative to the total mass of the acrylic resin composition.

The polymerization method for the acrylic core-shell rubber (AA) is not particularly limited, and examples thereof include emulsion polymerization and suspension polymerization. In the case of emulsion polymerization, it is preferable to use an emulsifier, a radical polymerization initiator, and a chain transfer agent.
The emulsifier, radical polymerization initiator, and chain transfer agent used in the emulsion polymerization are preferably the same as those used in the core-shell rubber (A) described above.

(Crosslinked particles (B))
The crosslinked particles (B) have an average particle size of 0.1 to 10 μm. If the average particle size of the crosslinked particles (B) is equal to or greater than the lower limit, the film can be prevented from sticking to the roll during production. This prevents the film from breaking or having surface defects when peeled from the roll surface. If the average particle size of the crosslinked particles (B) is equal to or less than the upper limit, the transparency of the film is easily maintained, and the film is less likely to slip when wound onto the roll. The average particle size of the crosslinked particles (B) is preferably equal to or greater than 0.3 μm, more preferably equal to or greater than 0.5 μm, and is preferably equal to or less than 8 μm, more preferably equal to or less than 6 μm.
The average particle size is a volume-average converted median size measured using a laser diffraction/scattering particle size distribution measuring device.

From the viewpoint of the transparency of the resulting film, it is preferable to use crosslinked particles (B) having a refractive index of 1.45 or more and 1.53 or less, and it is even more preferable to use crosslinked particles having a refractive index of 1.47 or more and 1.51 or less.

The crosslinked particles (B) are not particularly limited, and examples include organic crosslinked particles, inorganic crosslinked particles, and organic-inorganic composite particles. As the crosslinked particles (B), one type may be used alone, or two or more types may be used in combination.

Examples of the organic crosslinked particles include crosslinked styrene resin particles, crosslinked acrylic resin particles, crosslinked urethane resin particles, crosslinked melamine resin particles, and crosslinked phenolic resin particles.
The crosslinked styrene resin particles can be obtained, for example, by polymerizing a styrene-based monomer (styrene, methylstyrene, ethylstyrene, etc.) with a crosslinkable monomer, or by polymerizing a (meth)acrylic acid alkyl ester (methyl methacrylate, n-butyl methacrylate, methyl acrylate, n-butyl acrylate, etc.) with a crosslinkable monomer. Examples of the crosslinkable monomer include the same monomers as those used for the crosslinkable monomer (a14).

Examples of inorganic crosslinked particles include particles of silicon dioxide, aluminosilicate, magnesium silicate such as talc, aluminum silicate such as kaolin, alumina, titania, aluminum borate, calcium carbonate, and silicone resin.
As the crosslinked particles (B), organic crosslinked particles are preferred, and crosslinked acrylic resin particles are more preferred.

The content of crosslinked particles (B) in the acrylic resin composition is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.02% by mass or more, relative to the total mass of the acrylic resin composition; on the other hand, it is preferably 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. If the content of crosslinked particles (B) is at least the above-mentioned lower limit, it is easy to prevent the film from sticking to the roll during production. If the content of crosslinked particles (B) is at most the above-mentioned upper limit, it is easy to maintain the transparency of the film.

The content of crosslinked particles (B) in the acrylic resin composition is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and particularly preferably 0.02% by mass or more, relative to 100% by mass of core-shell rubber (A). It is also preferably 1% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less. If the content of crosslinked particles (B) is at least the lower limit, it is easy to prevent the film from sticking to the roll during production. If the content of crosslinked particles (B) is at most the upper limit, it is easy to maintain the transparency of the film.

(Thermoplastic polymer (C))
The acrylic resin composition may contain, in addition to the core-shell rubber (A) and the crosslinked particles (B), a thermoplastic polymer (C) other than the core-shell rubber (A).
The thermoplastic polymer (C) is preferably a polymer obtained by polymerizing a monomer composition containing an alkyl methacrylate ester as a main component, and more preferably a polymer obtained by polymerizing a monomer other than an alkyl methacrylate ester, an alkyl acrylate ester, and an alkyl (meth)acrylate ester.

Examples of the alkyl methacrylate ester used in thermoplastic polymer (C) include methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Examples of the alkyl acrylate ester include methyl acrylate, ethyl acrylate, and butyl acrylate. Examples of other monomers include aromatic vinyl monomers such as styrene, vinyl cyanide monomers such as acrylonitrile, unsaturated dicarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride, N-phenylmaleimide, and N-cyclohexylmaleimide. These monomers used in thermoplastic polymer (C) may be used alone or in combination of two or more.

Preferably, the thermoplastic polymer (C) is a polymer containing 50 to 99.9% by mass of alkyl methacrylate units having an alkyl group with 1 to 4 carbon atoms, 0.1 to 50% by mass of alkyl acrylate units, and 0 to 49.9% by mass of other monomer units (total 100% by mass).

The mass average molecular weight of the thermoplastic polymer (C) is preferably 10,000 or more, and preferably 300,000 or less. When the mass average molecular weight is equal to or more than the lower limit, the acrylic resin film has excellent handleability. When the mass average molecular weight is equal to or less than the upper limit, the film formability is good.
The thermoplastic polymer (C) contained in the acrylic resin composition may be one type or two or more types.

The method for producing the thermoplastic polymer (C) is not particularly limited, and various polymerization methods such as suspension polymerization, emulsion polymerization, and bulk polymerization can be used. Chain transfer agents and other polymerization aids may be used during polymerization. While there are no particular limitations on the chain transfer agent, mercaptans are preferred.

The content of thermoplastic polymer (C) in the acrylic resin composition is preferably 20% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less, relative to the total mass of the acrylic resin composition, and may even be 0% by mass. When the content of thermoplastic polymer (C) is equal to or less than the upper limit, the flexibility of the film is improved, and whitening during bending and other processes is more easily suppressed.

The acrylic resin composition may contain particles other than the crosslinked particles (B).
Examples of the other particles (D) include particles (D) having an average particle size of less than 0.1 μm.
The average particle size of the particles (D) is preferably 5 nm or more, and on the other hand, is preferably 10 nm or less, and more preferably 50 nm or less.

The type of particles (D) is not particularly limited, and examples include the organic crosslinked particles, inorganic crosslinked particles, and organic-inorganic composite particles exemplified as crosslinked particles (B). As particles (D), one type may be used alone, or two or more types may be used in combination.

The content of particles (D) in the acrylic resin composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, relative to the total mass of the acrylic resin composition, and is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.4% by mass or less. If the content of particles (D) is at least the lower limit, the produced film exhibits good blocking properties. If the content of particles (D) is at most the upper limit, the produced film exhibits good transparency.

(Additives)
The acrylic resin composition may contain additives such as stabilizers, lubricants, processing aids, plasticizers, impact resistance improvers, foaming agents, fillers, colorants, ultraviolet absorbers, etc. The additives contained in the acrylic resin composition may be one type or two or more types.

In the first embodiment, when a 50 μm thick, 15 mm wide test piece made of an acrylic resin composition is prepared in accordance with ISO 527:2012, the tensile modulus of the test piece measured at a temperature of 23°C, a tensile speed of 100 mm/min, and a chuck distance of 100 mm is preferably 1000 MPa or less, more preferably 900 MPa or less, even more preferably 800 MPa or less, and particularly preferably 700 MPa or less, while preferably 100 MPa or more, more preferably 300 MPa or more, and even more preferably 400 MPa or more. When the tensile modulus is equal to or less than the upper limit, the flexibility of the film formed using the acrylic resin composition is improved, and whitening of the film during bending and other processes can be suppressed. When the tensile modulus is equal to or greater than the lower limit, blocking between acrylic resin films is suppressed, and the film is imparted with appropriate rigidity, resulting in good handleability.

The gel fraction of the acrylic resin composition is preferably 5% or more, preferably 90% or less, and more preferably 80% or less. The higher the gel fraction, the better the toughness of the film, improving its handling and formability. Furthermore, the lower the gel fraction, the more effectively the resin is prevented from producing thermally degraded foreign matter, resulting in a better film appearance. From the perspective of film toughness, the gel fraction of the acrylic resin composition is more preferably 45% or more, particularly preferably 50% or more, and even more preferably 80% or less. From the perspective of film appearance, the gel fraction of the acrylic resin composition is preferably 5% or more, more preferably 30% or less, and especially preferably 25% or less.

The melt flow rate (MFR) of the acrylic resin composition at 230°C and a load of 49 N is preferably 0.1 g/10 min or more, more preferably 1 g/10 min or more, and even more preferably 3 g/10 min or more, while it is preferably 100 g/10 min or less, more preferably 50 g/10 min or less, and even more preferably 20 g/10 min or less. If the MFR of the acrylic resin composition is above the lower limit, the moldability during melt molding is good, and the surface smoothness of the melt-molded film is improved, resulting in a good appearance. If the MFR of resin composition (A) is below the upper limit, the moldability during melt molding is good.

As described above, the acrylic resin composition of the first embodiment comprises a specific core-shell rubber (A) blended with specific crosslinked particles (B). The inclusion of a core-shell rubber (A) with a graft ratio of 40% or less improves the flexibility of a film formed using the acrylic resin composition, suppressing whitening of the film during bending and other processes. Furthermore, the inclusion of crosslinked particles (B) with a specific average particle size prevents the film from sticking to the surfaces of various rolls, such as cooling rolls, during film production, improving productivity. Furthermore, the film is prevented from breaking or having surface defects when peeled from the roll surface. In this way, the acrylic resin composition of the first embodiment can simultaneously suppress sticking to roll surfaces and whitening during bending and other processes.

Second Embodiment
The acrylic resin composition of the second embodiment contains crosslinked particles (B), and has a tensile modulus of 1000 MPa or less, as measured in accordance with ISO 527:2012 on a test piece having a thickness of 50 μm and a width of 15 mm under conditions of a temperature of 23° C., a tensile speed of 100 mm/min, and a chuck distance of 100 mm.

The crosslinked particles (B) contained in the acrylic resin composition of the second embodiment are the same as the crosslinked particles (B) described in the first embodiment, and the preferred aspects are also the same. For the same reasons as in the first embodiment, the content of the crosslinked particles (B) in the acrylic resin composition of the second embodiment is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.02% by mass or more, relative to the total mass of the acrylic resin composition, and is preferably 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. In the second embodiment, too, by blending crosslinked particles (B) of a specific average particle size in a specific ratio, it is possible to prevent the film from sticking to the surface of various rolls, such as a cooling roll, during the production of a film using the acrylic resin composition.

In the second embodiment, the tensile modulus of elasticity of a test piece made from the acrylic resin composition is 1000 MPa or less. This improves the flexibility of a film formed using the acrylic resin composition, and whitening of the film can be suppressed when subjected to bending processing, etc. The tensile modulus of elasticity of a test piece made from the acrylic resin composition of the second embodiment is preferably 100 MPa or more, more preferably 300 MPa or more, and even more preferably 400 MPa or more, while preferably 900 MPa or less, more preferably 800 MPa or less, and even more preferably 700 MPa or less.

The component other than the crosslinked particles (B) of the acrylic resin composition of the second embodiment is preferably the core-shell rubber (A) described in the first embodiment, and thermoplastic polymer (C) and additives may also be used as needed. The tensile modulus can be adjusted by the composition and content of the core-shell rubber (A); for example, the lower the graft ratio, the lower the tensile modulus.

For the same reasons as in the first embodiment, the content of the core-shell rubber (A) in the acrylic resin composition of the second embodiment is preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, relative to the total mass of the acrylic resin composition. On the other hand, it is preferably 99.899% by mass or less, more preferably 99.89% by mass or less, and even more preferably 99.78% by mass or less.

The content of crosslinked particles (B) in the acrylic resin composition is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and particularly preferably 0.02% by mass or more, relative to 100% by mass of core-shell rubber (A). It is also preferably 1% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less. If the content of crosslinked particles (B) is at least the lower limit, it is easy to prevent the film from sticking to the roll during production. If the content of crosslinked particles (B) is at most the upper limit, it is easy to maintain the transparency of the film.

For the same reasons as in the first embodiment, the content of thermoplastic polymer (C) in the acrylic resin composition of the second embodiment is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and preferably 20% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less, relative to the total mass of the acrylic resin composition.

For the same reasons as in the first embodiment, the gel fraction of the acrylic resin composition in the second embodiment is preferably 5% or more, and is preferably 90% or less, and more preferably 80% or less. From the perspective of film toughness, the gel fraction of the acrylic resin composition is more preferably 45% or more, and particularly preferably 50% or more, and even more preferably 80% or less. Furthermore, from the perspective of film appearance, the gel fraction of the acrylic resin composition is preferably 5% or more, and is more preferably 30% or less, and particularly preferably 25% or less.

For the same reasons as in the first embodiment, the MFR of the acrylic resin composition of the second embodiment at 230°C and a load of 49 N is preferably 0.1 g/10 min or more, more preferably 1 g/10 min or more, and even more preferably 3 g/10 min or more, and preferably 100 g/10 min or less, more preferably 50 g/10 min or less, and even more preferably 20 g/10 min or less.

In the second embodiment described above, specific crosslinked particles (B) are also blended into the acrylic resin composition. This prevents the film from sticking to the surfaces of various rolls, such as cooling rolls, during film production, improving productivity. It also prevents the film from breaking or having surface defects when peeled from the roll surface. Furthermore, because the tensile modulus is controlled to 1000 MPa or less, films formed using the acrylic resin composition have good flexibility and are prevented from whitening during bending and other processes. In this way, the second embodiment also achieves both the effect of preventing the film from sticking to roll surfaces and the effect of preventing whitening during bending and other processes.

[film]
The film of the present invention is a film having at least an acrylic resin layer (hereinafter also referred to as "acrylic resin layer (I)") made of the acrylic resin composition of the present invention. The film of the present invention may be a single-layer film consisting of only the acrylic resin layer (I), or may be a laminate film containing the acrylic resin layer (I) and a resin layer other than the acrylic resin layer (I).

The other resin layer is not particularly limited, and examples include an acrylic resin layer made from an acrylic resin composition other than the acrylic resin composition of the present invention, a fluororesin layer made from a fluororesin composition, a polyolefin resin layer made from a polyethylene resin composition or a polypropylene resin composition, and a polyurethane resin layer made from a thermoplastic polyurethane resin composition. As a laminate film, a laminate film in which an acrylic resin layer (I) and a fluororesin layer are laminated is preferred because of its excellent weather resistance and chemical resistance.

The fluororesin composition may consist of a fluororesin alone, or may contain additives such as various acrylic resins, antioxidants, matting agents, stabilizers, lubricants, processing aids, ultraviolet absorbers, etc. The additives contained in the fluororesin composition may be one type or two or more types.
The inclusion of a matting agent reduces the glossiness of the film surface, improving the design properties. As the matting agent, organic and inorganic matting agents can be used, and among them, matting agents made of copolymers containing hydroxyl groups are preferred. As the fluororesin, vinylidene fluoride resins are preferred, and polyvinylidene fluoride, a homopolymer of vinylidene fluoride, is particularly preferred. Commercially available polyvinylidene fluoride products include Kynar 720 (vinylidene fluoride content: 100% by mass, crystalline melting point: 169°C) and Kynar 710 (vinylidene fluoride content: 100% by mass, crystalline melting point: 169°C) manufactured by Arkema K.K.; KFT#850 (vinylidene fluoride content: 100% by mass, crystalline melting point: 173°C) manufactured by Kureha Corporation; and Solef 1006 (vinylidene fluoride content: 100% by mass, crystalline melting point: 174°C) and Solef 1008 (vinylidene fluoride content: 100% by mass, crystalline melting point: 174°C) manufactured by Solvay Specialty Polymers K.K.

The uses of the film are not particularly limited, and examples include roofing materials, siding materials, gutters, flooring materials, covering materials for building materials such as bathrooms and kitchens, covering materials for the interior and exterior of automobiles, covering materials for furniture, and agricultural vinyl greenhouses.

The thickness of the film of the present invention is preferably 5 μm or more, more preferably 10 μm or more, and preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 75 μm or less. When the film thickness is at least the above-mentioned lower limit, the film is easy to manufacture and has excellent weather resistance. When the film thickness is at most the above-mentioned upper limit, the film has appropriate flexibility and is less likely to whiten even when subjected to bending processing. In addition, it is economically advantageous in terms of mass per unit area. Furthermore, film formability is stable, making film production easy.

The thickness of the acrylic resin layer (I) is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 25 μm or more. It is also preferably 200 μm or less, more preferably 100 μm or less, even more preferably 75 μm or less, and particularly preferably 70 μm or less. When the thickness of the acrylic resin layer (I) is at least the above-mentioned lower limit, the film has good weather resistance. Furthermore, in the case of a laminated film with a fluorine-based resin layer, curling of the film is suppressed, improving handleability. When the thickness of the acrylic resin layer (I) is at most the above-mentioned upper limit, the film has adequate flexibility and is less likely to whiten even when bent. It is also economically advantageous in terms of mass per unit area.

In the case of a laminate film of an acrylic resin layer (I) and a fluororesin layer, the thickness of the fluororesin layer is preferably 0.1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more, while it is preferably 30 μm or less, more preferably 10 μm or less, and even more preferably 7 μm or less. If the thickness of the fluororesin layer is at least the above-mentioned lower limit, the chemical resistance of the laminate film will be good. If the thickness of the fluororesin layer is at most the above-mentioned upper limit, whitening during bending will be suppressed. Furthermore, it is economically advantageous in terms of mass per unit area.

The method for producing the film of the present invention is not particularly limited, and examples thereof include a method including the following steps (X) and (Y).
(X) A step of forming the acrylic resin composition of the present invention into a film.
(Y) A step of sandwiching the formed film between two rolls.

The molding method in step (X) is not particularly limited, and examples thereof include melt extrusion molding such as a T-die method and an inflation method.
The melting temperature during molding is preferably 150°C or higher, more preferably 200°C or higher, and is preferably 350°C or lower, more preferably 280°C or lower.

During molding, a masterbatch may be prepared by mixing the crosslinked particles (B) with part of the resin components containing the core-shell rubber (A) and, if necessary, the thermoplastic resin (C), and then this masterbatch may be melt-kneaded with the remainder of the resin components to form the molded product.

An example of step (Y) is a step of sandwiching a film extruded from a die between two rolls in melt extrusion molding. The two rolls may or may not have a temperature control function, or only one of the rolls may be temperature controlled. Since the higher the temperature of the roll, the more likely the film will stick to the roll surface, it is preferable that at least one of the rolls has a temperature control function.
As in step (Y), when a film extruded from a die by melt extrusion molding is sandwiched between two rolls, the film is particularly likely to stick to the roll surface. Furthermore, when one or both of the two rolls are mirror-finished metal rolls, the film is even more likely to stick to the roll surface. However, since the acrylic resin composition of the present invention contains crosslinked particles (B), sticking to the roll surface is suppressed even when sandwiched between a pair of rolls. Furthermore, even when at least one of the two rolls is a mirror-finished metal roll, sticking to the roll surface is suppressed, thereby improving productivity.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following descriptions. In the examples, "parts" means "parts by mass".
[Abbreviation]
The abbreviations used in the examples are as follows.
MMA: methyl methacrylate MA: methyl acrylate BA: n-butyl acrylate HEMA: 2-hydroxyethyl methacrylate AMA: allyl methacrylate BDMA: 1,3-butylene glycol dimethacrylate RS610NA: mono-n-dodecyloxytetraoxyethylene sodium phosphate (trade name: "Phosphanol RS-610NA", manufactured by Toho Chemical Industry Co., Ltd.)
OTP: "Pelex OT-P" (product name) manufactured by Kao Corporation
nOM: n-octyl mercaptan CHP: "Percumyl H" (trade name) manufactured by NOF Corporation
tBH: "Perbutyl H" (trade name) manufactured by NOF Corporation
LPO: NOF Corporation, "Perloil L" (product name)
TV1600: "Tinuvin 1600" (product name) manufactured by BASF
TV234: "Tinuvin 234" (product name) manufactured by BASF
C2020: "Chimassorb2020" (product name) manufactured by BASF
R976: "AEROSIL R976" (product name) manufactured by Nippon Aerosil Co., Ltd.
P551A: "Metablen P551A" (product name) manufactured by Mitsubishi Chemical Corporation
Irg1076: "Irganox 1076" (product name) manufactured by BASF
T850: "KFT#850" (product name) manufactured by Kureha Corporation

[Tensile modulus]
A test piece of 150 mm × 15 mm with the long side in the film formation direction was cut out from the acrylic resin film of each example, and a tensile test was carried out using an autograph tensile tester (trade name, manufactured by Shimadzu Corporation) at a chuck distance of 100 mm and a tensile speed of 100 mm/min, to measure the tensile modulus and tensile elongation at break of the film.

[Average particle diameter]
The particles were dispersed in ion-exchanged water and diluted to a concentration sufficient for measurement. The median diameter in volume terms was determined using a laser diffraction/scattering particle size distribution analyzer (manufactured by Shimadzu Corporation, trade name: "SALD-7100"), and the median diameter was taken as the average particle size.

[Gel fraction]
1 g of core-shell rubber (A) was dissolved in 50 g of acetone and refluxed at 70°C for 4 hours to obtain an acetone-soluble fraction. The obtained extract was centrifuged at 14,000 rpm at 4°C for 30 minutes using a CRG SERIES (manufactured by Hitachi, Ltd.). The precipitated acetone-insoluble fraction was removed by decantation and dried in a vacuum dryer at 50°C for 24 hours to obtain an acetone-soluble fraction. The gel fraction was calculated from the mass (g) of the obtained acetone-soluble fraction using the following formula.
Gel fraction (%) = 100 × (1 - mass of acetone soluble matter)

[Mass average molecular weight]
The acetone soluble fraction of the core-shell rubber (A) obtained during gel fraction measurement was subjected to GPC measurement under the following conditions, and the mass average molecular weight was determined from a calibration curve using standard polystyrene.
Device: "HLC8220" manufactured by Tosoh Corporation
Column: "TSKgel SuperMultipore HZ-H" manufactured by Tosoh Corporation (inner diameter 4.6 mm x length 15 cm x 2 columns, estimated exclusion limit 4 x 10 ⁷ )
Eluent: tetrahydrofuran Eluent flow rate: 0.35 mL/min Measurement temperature: 40°C
Sample injection volume: 10 μL (sample concentration 0.1%)

[MFR]
The MFR value was measured under conditions of a temperature of 230°C and a load of 49N in accordance with ASTM D1238.

[Production Example 1: Core-shell rubber (A-1)]
In a polymerization vessel equipped with a stirrer, a cooling tube, a thermocouple, and a nitrogen inlet tube, 195 parts of deionized water was charged, followed by the component (ii) shown below, and the temperature was raised to 60° C. After the temperature was raised, 5 parts of deionized water and the component (i) shown below were charged to initiate polymerization. After the peak temperature was confirmed, the reaction was continued for 15 minutes to complete the polymerization.
Next, component (iii) shown below was added dropwise to the polymerization vessel over 120 minutes. Thereafter, the reaction was continued for 60 minutes to complete the polymerization of the core portion. The Tg of the core portion was -49°C. Next, component (iv) shown below was added dropwise to the polymerization vessel over 120 minutes, and the reaction was continued for 60 minutes to form a shell portion on the core portion. Through the above steps, a latex-like core-shell rubber was obtained. The Tg of the shell portion alone was 79°C.
The latex-like core-shell rubber was dropped into 300 parts of hot water at 70°C containing 3.8 parts of calcium acetate to coagulate the latex. The temperature was then raised to 95°C and maintained for 5 minutes to solidify. The resulting coagulated material was separated, washed, and dried at 70°C for 24 hours to obtain powdered core-shell rubber (A-1).
The core-shell rubber (A-1) had a core ratio of 55% by mass, a graft ratio of 22% by mass, a gel fraction of 67%, and a mass average molecular weight of the acetone soluble matter of 36,800.

(Component (i))
Sodium formaldehyde sulfoxylate 0.2 parts Ferrous sulfate 0.0001 parts Disodium ethylenediaminetetraacetate 0.0003 parts (component (ii))
MMA 0.3 parts BA 4.7 parts AMA 0.082 parts CHP 0.025 parts OTP 1.0 parts (Component (iii))
MMA 3.0 parts BA 47.0 parts AMA 0.82 parts CHP 0.05 parts (Component (iv))
MMA 40.5 parts BA 4.5 parts tBH 0.061 parts nOM 0.30 parts

[Production Example 2: Core-shell rubber (A-2)]
A core-shell rubber (A-2) was obtained in the same manner as in Production Example 1, except that the amount of nOM used was changed to 0.35 parts. The core-shell rubber (A-2) had a core ratio of 55 mass%, a graft rate of 20 mass%, a gel fraction of 66%, and a mass average molecular weight of the acetone soluble matter of 33,000.

[Production Example 3: Core-shell rubber (A-3)]
A core-shell rubber (A-3) was obtained in the same manner as in Production Example 1, except that the amount of nOM used was changed to 0.25 parts. The core-shell rubber (A-3) had a core ratio of 55 mass%, a graft rate of 26 mass%, a gel fraction of 69%, and a mass average molecular weight of the acetone soluble matter of 40,400.

[Production Example 4: Core-shell rubber (X-1) (comparison)]
A vessel equipped with a stirrer was charged with 8.5 parts of deionized water, and then component (vi) shown below was added while stirring. The mixture was stirred for 20 minutes to prepare an emulsion. Next, 191.5 parts of deionized water and component (v) shown below were charged into a polymerization vessel equipped with a cooler, and the temperature was raised to 70°C. Next, while stirring under nitrogen, the prepared emulsion was added dropwise into the polymerization vessel over 8 minutes, and the reaction was continued for 15 minutes. Subsequently, component (vii) shown below was added dropwise into the polymerization vessel over 90 minutes, and the reaction was continued for 60 minutes to obtain a core latex. The Tg of the core was −48°C. Subsequently, component (viii) shown below was added dropwise into the polymerization vessel over 45 minutes, and the reaction was continued for 60 minutes to form an intermediate portion on the core. The Tg of the intermediate portion alone was 20°C.
Subsequently, component (ix) shown below was added dropwise to the polymerization vessel over 140 minutes, and the reaction was continued for 60 minutes to form a shell portion on the intermediate portion. Through the above steps, a latex containing 100 parts of core-shell rubber (X-1) was obtained. The shell portion alone had a Tg of 84°C. The average particle size of the core-shell rubber (X-1) measured after polymerization was 0.12 μm.
This core-shell rubber (X-1) latex was subjected to coagulation, aggregation and solidification reactions using calcium acetate, filtered, washed with water and dried to obtain core-shell rubber (X-1).
The core-shell rubber (X-1) had a core ratio of 30% by mass, a graft ratio of 50% by mass, a gel fraction of 65%, and a mass average molecular weight of the acetone soluble matter of 58,000.

(Component (v))
Sodium formaldehyde sulfoxylate 0.2 parts Ferrous sulfate 0.0001 parts Disodium ethylenediaminetetraacetate 0.0003 parts (component (vi))
MMA 0.3 parts BA 4.5 parts AMA 0.05 parts BDMA 0.2 parts CHP 0.025 parts RS610NA 1.1 parts (Component (vii))
MMA 1.5 parts BA 22.5 parts AMA 0.25 parts BDMA 1.0 parts CHP 0.016 parts (Component (viii))
MMA 6.0 parts BA 4.0 parts AMA 0.075 parts CHP 0.013 parts (Component (ix))
MMA 55.2 parts BA 4.8 parts nOM 0.22 parts tBH 0.075 parts

[Crosslinked particles (B)]
B-1: Product name "Eposter (registered trademark) MV1004", average particle size: 4 μm, refractive index: 1.51, manufactured by Nippon Shokubai Co., Ltd.

[Particles (D)]
D-1: Product name "Aerosil (registered trademark) R976", average particle size: 7 nm, manufactured by Nippon Aerosil Co., Ltd.

[Production Example 5]
The following monomer mixture (1) was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas inlet, etc. Next, the atmosphere inside the vessel was thoroughly purged with nitrogen gas, and then the monomer mixture (1) in the reaction vessel was heated to 75°C while stirring and reacted for 3 hours in a nitrogen gas stream. Thereafter, the temperature inside the reaction vessel was raised to 90°C and further maintained at 90°C for 45 minutes to complete the polymerization. The mixture was sieved through a 100 μm mesh, and the passed-through beads were dehydrated and dried to obtain a hydroxyl group-containing polymer (E).
The resulting hydroxyl group-containing polymer (E) had a glass transition temperature of 77° C., an intrinsic viscosity of 0.11 L/g, Mw/Mn of 2.1, and an average particle size of 70 μm.

<Monomer mixture (1)>
MA: 10 parts, MMA: 60 parts, HEMA: 30 parts, nOM: 0.18 parts, LPO: 1 part, tricalcium phosphate: 1.8 parts, deionized water: 250 parts

[Production Example 6]
68 parts of T850 as a fluorine-based resin, 9 parts of a hydroxyl group-containing polymer (E), 18 parts of the rigid (co)polymer (B-1) of Production Example 7 in JP-A No. 2003-313392, 0.8 parts of the copolymer composition (b-2) (Mw=160,000) of Reference Example 2 in JP-A No. 2000-319516, 5 parts of the thermoplastic polymer (VII-1) (Mw=1,500,000) of JP-A No. 2005-139416, and 0.8 parts of an antioxidant (manufactured by ADEKA Corporation, trade name: Adekastab AO-60) were mixed.
This mixture was extruded into a strand shape using a degassing extruder under conditions of a cylinder temperature of 100 to 240°C and a die temperature of 250°C while removing impurities with a screen mesh, and the extruded strand was cooled by passing through a water bath, and then cut and pelletized to obtain a fluororesin composition (F).

[Example 1]
100 parts of the core-shell rubber (A-1) obtained in Production Example 1, 0.02 parts of particles (B-1), 0.3 parts of particles (D-1), 1.0 parts of TV1600, 1.2 parts of TV234, 0.34 parts of C2020, 1 part of P551A, and 0.1 parts of Irg1076 were premixed and melt-kneaded under conditions of a cylinder temperature of 200 ° C. to 240 ° C. and a die temperature of 240 ° C. using a 35 mmφ screw-type twin-screw extruder (L / D = 26), and pelletized to obtain an acrylic resin composition. The melt flow rate (MFR) of the acrylic resin composition at 230 ° C. and a load of 49 N was 8.4 g / 10 min.
The resulting acrylic resin composition pellets were melt-extruded using a 40 mmφ (diameter) non-vent screw extruder (L/D = 33) equipped with a 400 mm wide T-die, and the extruded film was cooled between a pair of mirror-finished metal rolls and rubber rolls to form a 50 μm thick film. The extrusion conditions were a cylinder temperature of 240°C and a T-die temperature of 240°C. The mirror-finished metal roll temperature was 85°C. The resulting film had a tensile modulus of 600 MPa.

[Examples 2 to 5]
Films were obtained in the same manner as in Example 1, except that the formulation of the acrylic resin composition was changed as shown in Table 1.

[Example 6]
The composition of the acrylic resin composition was changed as shown in Table 1. Furthermore, T850 was used as the fluororesin composition.
Using the obtained acrylic resin composition and fluororesin composition, an acrylic resin film (laminated film) having a thickness of 50 μm, in which an acrylic resin layer and a fluororesin layer were laminated, was formed using a two-kind, two-layer multi-manifold die set at 240° C. The thickness of the acrylic resin layer was 45 μm, and the thickness of the fluororesin layer was 5 μm.

[Example 7]
A laminated film having a thickness of 55 μm was obtained in the same manner as in Example 6, except that fluororesin composition (F) was used instead of T850 and the thickness of the fluororesin layer was changed to 10 μm.

[Comparative Examples 1 to 4]
Films were obtained in the same manner as in Example 1, except that the formulation of the acrylic resin composition was changed as shown in Table 1.

[Film forming property]
The film-forming properties were evaluated by the following method.
The film extruded from the T-die was sandwiched between a mirror-finished metal roll and a rubber roll and cooled, and the length of the film adhering to the mirror-finished metal roll was observed when the cooled film was peeled off from the mirror-finished metal roll along the rubber roll.
(Evaluation criteria)
○: Adhesion length is less than 1 cm.
△: Adhesion length is 1 cm or more and less than 3 cm.
×: Adhesion length is 3 cm or more.

[Bending workability]
The bending workability was evaluated by the following method.
A laminate molded product was obtained by hot pressing a film at 140°C onto a steel plate decorative sheet consisting of a 0.5 to 1.0 mm thick steel plate and a 0.1 to 0.3 mm thick black vinyl chloride layer laminated thereon. In the case of a laminate film, the resin layer (I) was laminated so that it was in contact with the black vinyl chloride layer. After adjusting the temperature of the obtained laminate molded product to -30°C, it was bent 90° over 1 second with the steel plate side facing inward, and the change in appearance of the laminate molded product was visually evaluated according to the following criteria.
(Evaluation criteria)
○: The bending support portion is not whitened.
△: The bending support part is slightly whitened.
×: The bending support part is whitened.

The composition of the acrylic resin composition, the tensile modulus of the film, and the evaluation results for the examples and comparative examples are shown in Table 1.

As shown in Table 1, the films of Examples 1 to 7, which used the acrylic resin composition containing the core-shell rubber (A) and the crosslinked particles (B), were prevented from sticking to the surface of the cooling roll, and were prevented from whitening even when subjected to bending processing.
On the other hand, the films of Comparative Examples 1 and 2, which had a high graft ratio of the core-shell rubber, were not sufficiently inhibited from whitening when subjected to bending processing. The films of Comparative Examples 3 and 4, which did not contain the crosslinked particles (B), were not sufficiently inhibited from sticking to the surface of the cooling roll.

Claims (10)

An acrylic resin composition containing a core-shell rubber (A) and crosslinked particles (B),
the crosslinked particles (B) have an average particle size of 0.1 to 10 μm, which is a volume-average converted median size measured using a laser diffraction/scattering particle size distribution analyzer;
The core-shell rubber (A) contains a core portion having a glass transition temperature of 0°C or lower and a shell portion having a glass transition temperature of higher than 20°C, and has a graft ratio of 40% or lower,
The acrylic resin composition has a content of the crosslinked particles (B) of 0.001 to 1 mass % . The acrylic resin composition according to claim 1, wherein the tensile modulus measured in accordance with ISO 527:2012 using a test piece 50 μm thick and 15 mm wide at a temperature of 23°C, a pulling rate of 100 mm/min, and a chuck distance of 100 mm, is 1000 MPa or less. An acrylic resin composition containing crosslinked particles (B),
the crosslinked particles (B) have an average particle size of 0.1 to 10 μm, which is a volume-average converted median size measured using a laser diffraction/scattering particle size distribution analyzer;
the content of the crosslinked particles (B) is 0.001 to 1 mass %,
An acrylic resin composition having a tensile modulus of 1000 MPa or less, measured in accordance with ISO 527:2012 using a test piece having a thickness of 50 μm and a width of 15 mm at a temperature of 23°C, a pulling rate of 100 mm/min, and a chuck distance of 100 mm. A film having at least an acrylic resin layer made of the acrylic resin composition according to any one of claims 1 to 3 . The film according to claim 4 , wherein the acrylic resin layer and a fluororesin layer made of a fluororesin composition are laminated together. The laminated laminated sheet has at least an acrylic resin layer made of an acrylic resin composition containing a core-shell rubber (A) and crosslinked particles (B),
the crosslinked particles (B) have an average particle size of 0.1 to 10 μm, which is a volume-average converted median size measured using a laser diffraction/scattering particle size distribution analyzer;
The core-shell rubber (A) contains a core portion having a glass transition temperature of 0°C or lower and a shell portion having a glass transition temperature of higher than 20°C, and has a graft ratio of 40% or lower,
A film comprising the acrylic resin layer and a fluororesin layer made of a fluororesin composition laminated together. The film has at least an acrylic resin layer made of an acrylic resin composition containing crosslinked particles (B),
the crosslinked particles (B) have an average particle size of 0.1 to 10 μm, which is a volume-average converted median size measured using a laser diffraction/scattering particle size distribution analyzer;
the acrylic resin composition has a tensile modulus of 1000 MPa or less, as measured in accordance with ISO 527:2012 on a test piece having a thickness of 50 μm and a width of 15 mm under conditions of a temperature of 23° C., a pulling rate of 100 mm/min, and a chuck distance of 100 mm;
A film comprising the acrylic resin layer and a fluororesin layer made of a fluororesin composition laminated together. A method for producing a film, comprising a step of forming the acrylic resin composition according to any one of claims 1 to 3 into a film. The method according to claim 8 , further comprising the step of sandwiching the formed film between two rolls. 10. The method of claim 9 , wherein at least one of the two rolls is a mirror-finished metal roll.