阅读说明：本技术 热塑性树脂组合物及成型品 (Thermoplastic resin composition and molded article ) 是由 小俣有辉 藤冈真佑 于 2018-07-17 设计创作，主要内容包括：本发明的热塑性树脂组合物含有：(A)橡胶增强乙烯基系树脂,其包含来自丙烯酸系橡胶质聚合物的橡胶质部分、和含有来自芳香族乙烯基化合物的结构单元及来自乙烯基氰化合物的结构单元的树脂部分构成；(B)(甲基)丙烯酸系树脂,其包含含有来自(甲基)丙烯酸烷基酯化合物的结构单元、且不含来自α-甲基苯乙烯的结构单元的(共)聚合物(但是,不包括成分(A)),和(C)α-甲基苯乙烯系树脂,其包含含有来自α-甲基苯乙烯的结构单元、且不含来自(甲基)丙烯酸烷基酯化合物的结构单元的(共)聚合物(但是,不包括成分(A)),分别含有10～70质量％、5～80质量％和5～70质量％的成分(A)、成分(B)和成分(C)(其中,它们的合计为100质量％)。(The thermoplastic resin composition comprises (A) a rubber-reinforced vinyl resin comprising a rubber part derived from an acrylic rubber polymer and a resin part comprising a structural unit derived from an aromatic vinyl compound and a structural unit derived from a vinyl cyanide compound, (B) a (meth) acrylic resin comprising a (co) polymer comprising a structural unit derived from an alkyl (meth) acrylate compound and not comprising a structural unit derived from α -methylstyrene (excluding component (A)), and (C) α -methylstyrene resin comprising a (co) polymer comprising a structural unit derived from α -methylstyrene and not comprising a structural unit derived from an alkyl (meth) acrylate compound (excluding component (A)), wherein the total of component (A), component (B) and component (C) is 100% by mass.)

1, A thermoplastic resin composition comprising:

(A) a rubber-reinforced vinyl resin comprising a rubbery portion derived from an acrylic rubbery polymer and a resin portion containing a structural unit derived from an aromatic vinyl compound and a structural unit derived from a vinyl cyanide compound;

(B) a (meth) acrylic resin comprising a (co) polymer containing a structural unit derived from an alkyl (meth) acrylate compound and not containing a structural unit derived from α -methylstyrene, excluding the rubber-reinforced vinyl resin (A), and

(C) α -a methylstyrene-based resin comprising a (co) polymer containing a structural unit derived from α -methylstyrene and not containing a structural unit derived from an alkyl (meth) acrylate compound, but excluding the rubber-reinforced vinyl-based resin (A),

the content of the rubber-reinforced vinyl resin (A), the content of the (meth) acrylic resin (B), and the content of the α -methylstyrene resin (C) are 10 to 70 mass%, 5 to 80 mass%, and 5 to 70 mass%, respectively, when the total content thereof is 100 mass%.

2. The thermoplastic resin composition according to claim 1, wherein the content ratio of the structural unit derived from the alkyl (meth) acrylate compound constituting the (meth) acrylic resin (B) is 50% by mass or more relative to the total amount of the structural units constituting the (meth) acrylic resin (B).

3. The thermoplastic resin composition according to claim 1 or 2, wherein the (meth) acrylic resin (B) is a resin further comprising structural units derived from an aromatic vinyl compound and structural units derived from a vinyl cyanide compound, but the aromatic vinyl compound does not include α -methylstyrene.

4. The thermoplastic resin composition of any of claims 1-3, wherein the proportion of structural units derived from α -methylstyrene that constitute the α -methylstyrene-based resin (C) is 60% by mass or more, relative to the total amount of structural units that constitute the α -methylstyrene-based resin (C).

5. The thermoplastic resin composition according to of claims 1 to 4, wherein the content of the rubbery portion constituting the rubber-reinforced vinyl-based resin (A) is 5 to 40% by mass based on the entire composition.

6, kinds of molded articles, which contains the thermoplastic resin composition according to any of of claims 1-5.

Technical Field

The present invention relates to a thermoplastic resin composition suitable for producing a molded article having excellent weather resistance.

Background

Molded articles comprising rubber-reinforced vinyl resins such as ABS resins, ASA resins and AES resins have been used in the fields of vehicles, home appliances, building materials and the like because of their excellent impact resistance and the like, and among these, is widely used as an ASA resin because the degree of reduction in color tone and surface gloss is small and the appearance is highly maintained in molded articles used outdoors or molded articles used indoors under the sun light.

Heretofore, molding materials for producing molded articles having excellent weather resistance are disclosed in, for example, patent documents 1 to 3 below.

Patent document 1 discloses a rubber-reinforced thermoplastic resin characterized by containing: the acrylic rubber polymer particles (a1) having a particle diameter of less than 350nm are contained in an amount of 50 to 98 wt% and the acrylic rubber polymer particles (a2) having a particle diameter of 350nm or more are contained in an amount of 2 to 50 wt% [ wherein the total amount of (a1) and (a2) is 100 wt%. A copolymer resin (a1) obtained by polymerizing a vinyl monomer (b1) in the presence of an acrylic rubber polymer (a), or a mixture of the copolymer resin (a1) and a (co) polymer (a2) of a vinyl monomer (b2), wherein the content of the acrylic rubber polymer (a) is 5 to 80% by weight based on the total resin.

Patent document 2 discloses a thermoplastic resin composition containing an acrylic rubber-based graft copolymer obtained by graft-polymerizing a vinyl monomer in the presence of a rubber polymer containing an acrylate monomer unit and a polyfunctional monomer unit, wherein the total amount of the polyfunctional monomer units in the rubber polymer is 0.3 to 3 parts by mass per 100 parts by mass of the acrylate monomer unit, and the total amount of the polyfunctional monomer units, 100% by mass, contains 30 to 95% by mass of a polyfunctional monomer unit having 2 unsaturated bonds and 5 to 70% by mass of a polyfunctional monomer unit having 3 unsaturated bonds.

Patent document 3 discloses a thermoplastic resin composition obtained by blending a graft copolymer (I) obtained by graft-polymerizing a monomer mixture (B) containing an aromatic vinyl monomer (C) and a vinyl cyanide monomer (d) in the presence of an acrylic rubber polymer (a) having a volume average particle diameter of 0.10 to 0.30 μm and obtained by copolymerizing 97 to 99.5 wt% of an acrylate monomer (a) and 0.5 to 3 wt% of a polyfunctional monomer (B), and a (meth) acrylic (co) polymer (II) obtained by polymerizing or copolymerizing a monomer or a monomer mixture (C) containing 50 to 100 wt% of an unsaturated carboxylic acid alkyl ester monomer (e), wherein the thermoplastic resin composition is obtained by blending 30 to 70 parts by weight of the graft copolymer (I) and 30 to 70 parts by weight of the (meth) acrylic (co) polymer (II) with a graft copolymer (β) having a graft ratio of (β) to 30 to 70 parts by weight of the graft copolymer (I) and a graft copolymer (I) having a swelling ratio of 3682.3682, β being a graft copolymer having a toluene rubber particle size of a graft copolymer (a) satisfying the above formula.

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a thermoplastic resin composition that produces a molded article having better weather resistance than conventionally known molding materials.

Means for solving the problems

The present invention is shown below.

1. A thermoplastic resin composition comprising (A) a rubber-reinforced vinyl resin comprising a rubber part derived from an acrylic rubber polymer and a resin part comprising a structural unit derived from an aromatic vinyl compound and a structural unit derived from a vinyl cyanide compound, (B) a (meth) acrylic resin comprising a (co) polymer comprising a structural unit derived from an alkyl (meth) acrylate compound and not comprising a structural unit derived from α -methylstyrene (excluding the rubber-reinforced vinyl resin (A)), and (C) α -methylstyrene resin comprising a (co) polymer comprising a structural unit derived from α -methylstyrene and not comprising a structural unit derived from an alkyl (meth) acrylate compound (excluding the rubber-reinforced vinyl resin (A)), wherein the content ratios of the rubber-reinforced vinyl resin (A), the (meth) acrylic resin (B), and the α -methylstyrene resin (C) are 10 to 70 mass%, 5 to 70 mass%, and 5 to 70 mass%, respectively, based on 100 mass% of the total of the rubber part and the resin part.

2. The thermoplastic resin composition according to item 1, wherein the content of the structural unit derived from the alkyl (meth) acrylate compound constituting the (meth) acrylic resin (B) is 50% by mass or more based on the total amount of the structural units constituting the (meth) acrylic resin (B).

3. The thermoplastic resin composition as described in item 1 or 2, wherein the (meth) acrylic resin (B) is a resin further comprising structural units derived from an aromatic vinyl compound (excluding α -methylstyrene) and structural units derived from a vinyl cyanide compound.

4. The thermoplastic resin composition of any of items 1 to 3, wherein the content of the structural unit derived from α -methylstyrene that constitutes the α -methylstyrene-based resin (C) is 60% by mass or more based on the total amount of the structural units that constitute the α -methylstyrene-based resin (C).

5. The thermoplastic resin composition according to any of items 1 to 4, wherein the content of the rubbery portion constituting the rubber-reinforced vinyl-based resin (A) is 5 to 40% by mass based on the entire composition.

6. A molded article comprising the thermoplastic resin composition according to any of items 1 to 5 above.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the thermoplastic resin composition of the present invention, a molded article having excellent weather resistance can be obtained, in which changes in color tone and reduction in surface gloss are suppressed when used outdoors in the sun for bathing, and the like.

Detailed Description

The present invention will be described in detail below. In the present specification, "(meth) acrylic acid" means acrylic acid and methacrylic acid, "(meth) acrylate" means acrylate and methacrylate, "(meth) acryloyl group" means acryloyl group and methacryloyl group, "(meth) allyl group" means allyl group and methallyl group, and "(co) polymer" means homopolymer and copolymer.

The thermoplastic resin composition of the present invention is a composition comprising (A) a rubber-reinforced vinyl resin comprising a rubber part derived from an acrylic rubber polymer and a resin part comprising a structural unit derived from an aromatic vinyl compound and a structural unit derived from a vinyl cyanide compound (hereinafter referred to as "component (A)") (B) a (meth) acrylic resin comprising a (co) polymer comprising a structural unit derived from an alkyl (meth) acrylate compound (excluding the component (A) and the component (B) "), and (C) a α -methylstyrene resin comprising a (co) polymer comprising a structural unit derived from α -methylstyrene and not comprising a structural unit derived from an alkyl (meth) acrylate compound (excluding the component (A) and the component (C)") in a specific ratio.

The thermoplastic resin composition of the present invention comprises the components (A), (B) and (C) as essential components, and further may contain other thermoplastic resins and additives (both described below).

The component (A) is a rubber-reinforced vinyl resin comprising a rubber portion derived from an acrylic rubber polymer and a resin portion containing a structural unit derived from an aromatic vinyl compound and a structural unit derived from a vinyl cyanide compound. The content ratio of the rubber portion and the resin portion in the component (A) is not particularly limited, and when the total of both is 100% by mass, it is preferably 35 to 85% by mass and 15 to 65% by mass, more preferably 55 to 80% by mass and 20 to 45% by mass, respectively.

The component (a) is preferably a graft resin obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound and a vinyl cyanide compound in the presence of an acrylic rubber polymer, the graft resin having a rubber portion chemically bonded to a resin portion.

The acrylic rubber-like polymer is not particularly limited as long as it contains a (co) polymer containing a structural unit derived from an alkyl acrylate compound and has a glass transition temperature of less than 0 ℃.

The acrylic rubbery polymer is preferably a copolymer containing a structural unit derived from an alkyl acrylate compound (hereinafter referred to as "structural unit (x 1)") and a structural unit derived from a polyfunctional monomer (hereinafter referred to as "structural unit (x 2)"), and may further contain a structural unit derived from another monomer (hereinafter referred to as "structural unit (x 3)").

The content ratio of the structural units (x1) and (x2) constituting the acrylic rubber-based polymer of a preferred embodiment is preferably 95 to 99.99% by mass and 0.01 to 5% by mass, more preferably 97.5 to 99.9% by mass and 0.1 to 2.5% by mass, respectively, when the total of the two is 100% by mass, from the viewpoint of appearance, weather resistance and impact resistance. In the acrylic rubber-based polymer containing the structural unit (x3), the upper limit of the content of the structural unit (x3) is preferably 20% by mass, and more preferably 10% by mass, assuming that the total of the structural units (x1), (x2), and (x3) is 100% by mass.

The alkyl acrylate compound is preferably an alkyl acrylate compound having an alkyl group having 1 to 12 carbon atoms in the ester moiety, and examples thereof include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate. Of these, n-butyl acrylate is preferred.

The polyfunctional monomer is preferably a compound having 2 or more carbon-carbon unsaturated bonds, and particularly preferably a compound having 2 unsaturated bonds, a compound having 3 unsaturated bonds, or the like.

Examples of the compound having 2 unsaturated bonds include allyl (meth) acrylate, diallyl maleate, diallyl fumarate, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, trimethylolpropane triacrylate, 2-propenyl acrylate, divinylbenzene, and the like.

Examples of the other monomers include alkyl methacrylate compounds such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, and benzyl methacrylate; an aromatic vinyl compound; a vinyl cyanide compound; a maleimide compound; an unsaturated acid anhydride; a carboxyl group-containing unsaturated compound; an amino group-containing unsaturated compound; an amido group-containing unsaturated compound; unsaturated compounds containing hydroxyl groups, and the like.

The rubber portion constituting the component (A) preferably has a spherical shape or a deformed shape, and the volume average particle diameter thereof is preferably 60 to 500nm, more preferably 60 to 400nm, and further preferably 60 to 200nm in view of mechanical strength and appearance, and the volume average particle diameter thereof is generally 60 to 200nm in the step A sheet made of a molded article comprising the thermoplastic resin composition of the present invention is immersed in OsO₄Or RuO₄The solution (2) can be used as a volume-converted average value of the particle diameters measured for 100 rubbery portions of the component (a), for example, by observation with a transmission electron microscope.

In the aspect of , the resin portion constituting the component (A) contains a structural unit derived from an aromatic vinyl compound (hereinafter referred to as "structural unit (y 1)") and a structural unit derived from a vinyl cyanide compound (hereinafter referred to as "structural unit (y 2)"), and may further contain structural units (hereinafter referred to as "structural unit (y 3)") as necessary.

The aromatic vinyl compound forming the structural unit (y1) is not particularly limited as long as it has at least vinyl bonds and at least aromatic rings, and examples thereof include styrene, α -methylstyrene, o-methylstyrene, p-methylstyrene, β -methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyltoluene, vinylxylene, vinylnaphthalene, and the like.

Further, as the vinyl cyanide compound forming the above-mentioned structural unit (y2), acrylonitrile, methacrylonitrile, ethacrylonitrile, α -isopropylacrylonitrile and the like can be mentioned, and among these, acrylonitrile is preferred.

The content ratio of the structural units (y1) and (y2) in the resin portion constituting the component (a) is not particularly limited, and is preferably 60 to 95% by mass and 5 to 40% by mass, more preferably 65 to 85% by mass and 15 to 35% by mass, respectively, when the total of the two is 100% by mass, from the viewpoint of appearance and impact resistance.

The resin portion constituting the above component (A) may contain the structural units (y1) and (y2), or may contain the structural units (y1), (y2) and (y3) as described above. The upper limit of the content ratio of the structural unit (y3) when included is preferably 50% by mass, more preferably 30% by mass, assuming that the total amount of the structural units constituting the resin portion is 100% by mass.

Examples of the compound forming the structural unit (y3) include alkyl (meth) acrylate compounds; a maleimide compound; an unsaturated acid anhydride; a carboxyl group-containing unsaturated compound; an amino group-containing unsaturated compound; an amido group-containing unsaturated compound; unsaturated compounds containing hydroxyl groups, and the like.

Examples of the maleimide-based compound include maleimide, N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-dodecylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (4-methylphenyl) maleimide, N- (2, 6-dimethylphenyl) maleimide, N- (2, 6-diethylphenyl) maleimide, N-benzylmaleimide, N-naphthylmaleimide, and N-cyclohexylmaleimide. When a structural unit derived from a maleimide compound is introduced into a polymer chain, for example, a method of imidizing after copolymerizing maleic anhydride can be applied.

Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, and 2, 3-dimethylmaleic anhydride.

Examples of the unsaturated compound having a carboxyl group include (meth) acrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, and cinnamic acid.

Examples of the amino group-containing unsaturated compound include aminoethyl acrylate, propylaminoethyl acrylate, dimethylaminomethyl acrylate, diethylaminomethyl acrylate, 2-dimethylaminoethyl acrylate, aminoethyl methacrylate, propylaminoethyl methacrylate, dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate, 2-dimethylaminoethyl methacrylate, phenylaminoethyl methacrylate, p-aminostyrene, N-vinyldiethylamine, N-acetylvinylamine, acrylamide, methacrylamide, and N-methacrylamide.

Examples of the unsaturated compound containing an amido group include acrylamide, N-methacrylamide, and N-methylmethacrylamide.

Examples of the hydroxyl group-containing unsaturated compound include hydroxyl group-containing (meth) acrylates such as hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and polypropylene glycol mono (meth) acrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, o-hydroxy- α -methylstyrene, m-hydroxy- α -methylstyrene, p-hydroxy- α -methylstyrene, 2-hydroxymethyl- α -methylstyrene, 3-hydroxymethyl- α -methylstyrene, 4-hydroxymethyl- α -methylstyrene, 4-hydroxymethyl-1-vinylnaphthalene, 7-hydroxymethyl-1-vinylnaphthalene, 8-hydroxymethyl-1-vinylnaphthalene, 4-hydroxymethyl-1-isopropenylnaphthalene, 7-hydroxymethyl-1-isopropenylnaphthalene, 8-hydroxymethyl-1-vinylbenzyl alcohol, 8-hydroxymethyl-hydroxyisopropylnaphthalene, 4-hydroxymethyl-1-hydroxyisopropylnaphthalene, 4-2-hydroxypropyl-2-hydroxy-1-propenylbenzene, 4-2-hydroxy-1-propenylbenzene, and 4-hydroxy-1-propenylbenzene.

The graft ratio of the component (a) as a graft resin is preferably 20% or more, more preferably 25% or more, and further preferably 30 to 80% in steps, from the viewpoint of appearance and impact resistance.

The graft ratio can be determined by the following equation.

Graft ratio (%) { (S-T)/T } × 100

In the above formula, S is the mass (g) of an insoluble fraction obtained by charging 1g of component (A) into 20ml of acetonitrile, shaking the mixture for 2 hours with a shaker, centrifuging the mixture to separate the insoluble fraction from a soluble fraction, and T is the mass (g) of a rubbery portion derived from an acrylic rubbery polymer contained in 1g of component (A). The mass of the rubber portion can be obtained by a method of calculating from the polymerization formulation and the polymerization conversion rate, a method of obtaining by infrared absorption spectroscopy (IR), and the like.

As the above component (a), a rubber-reinforced vinyl-based resin having a rubber portion derived from an acrylic rubber-based polymer and a resin portion containing the structural units (y1) and (y2), or a rubber-reinforced vinyl-based resin having a rubber portion derived from an acrylic rubber-based polymer and a resin portion containing the structural units (y1), (y2) and (y3) is preferable.

The number of the component (A) contained in the thermoplastic resin composition of the present invention may be or two or more.

The component (B) is or more (meth) acrylic resins (excluding the component (a)) containing a (co) polymer containing a structural unit derived from an alkyl (meth) acrylate compound (hereinafter referred to as "structural unit (B1)") and not containing a structural unit derived from α -methylstyrene.

The content ratio of the structural unit (B1) contained in the component (B) is not particularly limited, and the lower limit of the content ratio of the structural unit (B1) contained in the component (B) is preferably 40% by mass, from the viewpoint of moldability and weather resistance, assuming that the total amount of the structural units contained in the component (B) is 100% by mass.

The alkyl (meth) acrylate compound forming the structural unit (b1) is preferably an alkyl methacrylate compound, and particularly preferably an alkyl methacrylate compound having an alkyl group having 1 to 5 carbon atoms in the ester portion.

The component (B) may contain or two or more species (hereinafter referred to as "component (B1)") of the structural unit (B1), may contain a structural unit (B1) and a structural unit (hereinafter referred to as "structural unit (B2)") derived from another monomer such as an aromatic vinyl compound (excluding α -methylstyrene), a vinyl cyanide compound, a maleimide-based compound, an unsaturated acid anhydride, a carboxyl-containing unsaturated compound, an amino-containing unsaturated compound, an amido-containing unsaturated compound, and a hydroxyl-containing unsaturated compound (hereinafter referred to as "component (B2)"), and in the case of the component (B2), the structural unit (B2) contained may be or two or more species, and the upper limit of the proportion of the total content thereof is preferably 60 mass% when the total amount of the structural units contained in the component (B2) is 100 mass%.

The other monomers forming the structural unit (b2) are preferably an aromatic vinyl compound (excluding α -methylstyrene) or a vinyl cyanide compound.

When the component (B2) contains structural units derived from an aromatic vinyl compound (excluding α -methylstyrene) as the structural units (B2), the content ratio thereof is preferably 1 to 49 mass%, more preferably 5 to 45 mass%, and even more preferably is 15 to 35 mass%, with the total amount of the structural units contained in the component (B2) being 100 mass%.

When the component (B2) contains structural units derived from a vinyl cyanide compound as the structural unit (B1), the content ratio thereof is preferably 1 to 36% by mass, more preferably 2 to 32% by mass, further is preferably 4 to 25% by mass, and particularly preferably 6 to 20% by mass, assuming that the total amount of the structural units contained in the component (B2) is 100% by mass.

As the aromatic vinyl compound, styrene is preferable. As the vinyl cyanide compound, acrylonitrile is preferred.

The content of the structural units in the case where the component (B2) contains the structural unit (B1), the structural unit derived from an aromatic vinyl compound (excluding α -methylstyrene), and the structural unit derived from a vinyl cyanide compound is preferably 50 to 98 mass%, 1 to 49 mass%, and 1 to 36 mass%, more preferably 60 to 81 mass%, 15 to 35 mass%, and 4 to 25 mass%, respectively, when the total of the structural units is 100 mass%.

As described above, as the above-mentioned component (B), the components (B1) and (B2) can be used, and in the present invention, a combination of these is a preferable embodiment, and a copolymer comprising a structural unit derived from an aromatic vinyl compound (excluding α -methylstyrene) and a structural unit derived from an aromatic vinyl compound (B1), and a copolymer comprising a structural unit derived from an aromatic vinyl compound (excluding α -methylstyrene) and a structural unit derived from a vinyl cyanide compound, or or more of the components (B1) and (B2), are preferably used.

The proportions of the components (B1) and (B2) when used together are preferably 30 to 90% by mass and 10 to 70% by mass, more preferably 40 to 80% by mass and 20 to 60% by mass, respectively, when the total of the components is 100% by mass, from the viewpoint of mechanical strength balance.

The intrinsic viscosity [ η ] (in methyl ethyl ketone, 30 ℃) of the component (B) is preferably 0.2 to 1.2dl/g, more preferably 0.3 to 1.0dl/g, and further more preferably 0.35 to 0.7dl/g in steps, from the viewpoint of moldability and mechanical strength.

The component (C) is a α -methylstyrene resin containing or more species (excluding the component (a)) of a (co) polymer containing a structural unit derived from α -methylstyrene (hereinafter referred to as a "structural unit (C1)") and not containing a structural unit derived from an alkyl (meth) acrylate compound.

The content ratio of the structural unit (C1) contained in the component (C) is preferably 60% by mass or more, more preferably 65 to 95% by mass, and further preferably 70 to 90% by mass in the step , when the total amount of the structural units is 100% by mass, from the viewpoint of weather resistance and heat resistance.

The component (C) may be poly (α -methylstyrene), or may contain a structural unit (C1) and a structural unit derived from another monomer (hereinafter referred to as "structural unit (C2)") such as an aromatic vinyl compound (excluding α -methylstyrene), a vinyl cyanide compound, a maleimide compound, an unsaturated acid anhydride, a carboxyl group-containing unsaturated compound, an amino group-containing unsaturated compound, an amido group-containing unsaturated compound, and a hydroxyl group-containing unsaturated compound).

The other monomers forming the above structural unit (c2) are preferably an aromatic vinyl compound (however, α -methylstyrene is not included) and a vinyl cyanide compound, as the aromatic vinyl compound, styrene is preferred, and as the vinyl cyanide compound, acrylonitrile is preferred.

The content ratio of the structural units when the component (C) contains the structural unit (C1), the structural unit derived from an aromatic vinyl compound (excluding α -methylstyrene) and the structural unit derived from a vinyl cyanide compound is preferably 40 to 95 mass%, 1 to 30 mass% and 4 to 40 mass%, more preferably 45 to 80 mass%, 3 to 25 mass% and 15 to 35 mass%, respectively, when the total of the structural units is 100 mass%.

When the component (C) contains the structural unit (C1) and the structural unit derived from a vinyl cyanide compound, the content of these structural units is preferably 60 to 95% by mass and 5 to 40% by mass, more preferably 65 to 85% by mass and 15 to 35% by mass, respectively, when the total of these structural units is 100% by mass.

The component (C) is preferably a copolymer, and particularly preferably a copolymer comprising the structural unit (C1), a structural unit derived from an aromatic vinyl compound (excluding α -methylstyrene), and a structural unit derived from a vinyl cyanide compound, or a copolymer comprising the structural unit (C1) and a structural unit derived from a vinyl cyanide compound.

The intrinsic viscosity [ η ] (in methyl ethyl ketone, 30 ℃) of the component (C) is preferably 0.2 to 1.2dl/g, more preferably 0.3 to 1.0dl/g, and further more preferably 0.35 to 0.7dl/g in steps, from the viewpoint of moldability and mechanical strength.

In the present invention, the content of the components (A), (B) and (C) is 10 to 70 mass%, 5 to 80 mass% and 5 to 70 mass%, preferably 15 to 65 mass%, 15 to 70 mass% and 7 to 55 mass%, more preferably 20 to 55 mass%, 20 to 60 mass% and 10 to 45 mass%, respectively, when the total of them is 100 mass%, from the viewpoint of suppressing the change in color tone and the reduction in surface gloss during long-term use outdoors or the like and obtaining a molded article having excellent weather resistance.

The thermoplastic resin composition of the present invention may contain other thermoplastic resins in addition to the components (A), (B) and (C) as described above. When another thermoplastic resin is contained, the upper limit of the content thereof is preferably 70 parts by mass, and more preferably 50 parts by mass, based on 100 parts by mass of the total of the components (a), (B), and (C).

Examples of the other thermoplastic resin include an aromatic vinyl copolymer containing a structural unit derived from an aromatic vinyl compound (excluding α -methylstyrene) and at least kinds of structural units derived from a vinyl cyanide compound, a maleimide compound, an unsaturated acid anhydride, a carboxyl group-containing unsaturated compound, an amino group-containing unsaturated compound, an amido group-containing unsaturated compound, and a hydroxyl group-containing unsaturated compound, a rubbery polymer-reinforced vinyl resin containing at least kinds of rubbery portions derived from a diene rubbery polymer, an ethylene- α -olefin rubbery polymer, a hydrogenated diene rubbery polymer, and a silicone rubbery polymer, and a resin portion containing a structural unit derived from a vinyl monomer excluding α -methylstyrene, a polyolefin resin, a polyamide resin, a polyester resin, a polycarbonate resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, and the like.

When the other thermoplastic resin is an aromatic vinyl copolymer, the intrinsic viscosity [ η ] (30 ℃ in methyl ethyl ketone) is preferably 0.2 to 1.0dl/g, more preferably 0.3 to 0.8dl/g, and further is preferably 0.4 to 0.7dl/g, from the viewpoints of moldability and mechanical strength.

In the thermoplastic resin composition of the present invention, the content of the rubbery portion constituting the component (a) is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and further preferably 15 to 35% by mass in , when the total of the components (a), (B), and (C) is 100% by mass, from the viewpoint of mechanical strength and appearance.

The content of the rubber portion constituting the component (a) is preferably 5 to 40% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 35% by mass of , based on the whole composition, from the viewpoint of mechanical strength and appearance.

The thermoplastic resin composition of the present invention may contain additives, as described above. Examples of the additives include fillers, plasticizers, antioxidants, ultraviolet absorbers, antioxidants, flame retardants, stabilizers, weather-resistant agents, light stabilizers, heat stabilizers, antistatic agents, water-proofing agents, oil-proofing agents, antibacterial agents, preservatives, colorants (pigments, dyes, etc.), and the like.

The thermoplastic resin composition of the present invention can be produced by kneading raw material components using various extruders, Banbury mixers, kneaders, rolls, Feeder-Ruder, etc., and can be prepared into pellets of a predetermined shape, etc. the kneading temperature is usually 220 to 270 ℃ depending on the kind, amount, etc. of the raw material components.

As the raw material for the component (a), a rubber-reinforced vinyl resin obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound and a vinyl cyan compound in the presence of an acrylic rubber polymer can be used. The rubber-reinforced vinyl resin generally contains the component (a) and an aromatic vinyl copolymer (other thermoplastic resin) containing a structural unit derived from an aromatic vinyl compound and a structural unit derived from a vinyl cyanide compound. The volume average particle diameter of the acrylic rubber polymer is substantially the same as the volume average particle diameter of the rubber portion constituting the component (a) contained in the thermoplastic resin composition of the present invention.

The molded article of the present invention is characterized by containing a thermoplastic resin composition. The molded article of the present invention can be produced by subjecting the thermoplastic resin composition to a conventionally known molding method such as an injection molding method, an injection compression molding method, a press molding method, an extrusion molding method, a co-extrusion molding method, a sheet extrusion molding method, a profile extrusion molding method, a vacuum molding method, a blow molding method, a compression molding method, a casting method, a roll molding method, or the like.

The molded article of the present invention is preferably used in an environment where sunlight is bathed outdoors or even indoors, and is suitable as a vehicle exterior, an outdoor use case, an exterior member, and the like, which are excellent in weather resistance. According to the evaluation method in [ example ] described below, the color difference before and after light irradiation, that is, the change in color tone Δ E, can be made preferably less than 1.0. In addition, the molded article of the present invention can be provided with a glossy surface, and in this case, the gloss retention ratio can be preferably 85% or more by the evaluation method in [ example ] described below.