Graft copolymer, thermoplastic resin composition, and molded article of said resin composition

1. A graft copolymer obtainable by polymerization of a vinyl-based monomer mixture (m1) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of a cross-linked ethylene.α-olefin copolymer (C) obtainable by cross-linking treatment of an ethylene.α-olefin copolymer (A) which has a mass average molecular weight (Mw) of 17×10 4 to 35×10 4 and a distribution of molecular weight (Mw/Mn) of 1 to 3, wherein the distribution of molecular weight is represented by the ratio of the mass average molecular weight (Mw) and the number-average molecular weight (Mn),

wherein a gel content ratio of the cross-linked ethylene α-olefin copolymer (C) with respect to the total amount of the cross-linked ethylene α-olefin copolymer (C) is 35 to 75% by mass.

2. The graft copolymer according to claim 1 , wherein the ethylene.α-olefin copolymer (A) is an ethylene.propylene copolymer.

3. The graft copolymer according to claim 1 , wherein the amount of ethylene units in the ethylene.α-olefin copolymer (A) with respect to the total amount of structural units constituting the ethylene.α-olefin copolymer (A) is 45 to 65% by mass.

4. The graft copolymer according to claim 1 , wherein the polymerization is emulsion polymerization.

5. A thermoplastic resin composition comprising: a graft copolymer (D) of claim 1 ; and a hard component (J).

6. The thermoplastic resin composition according to claim 5 , wherein the hard compound (J) is a styrene-comprising copolymer (H).

7. A thermoplastic resin composition comprising:

a graft copolymer of claim 1 ; and

a methacrylic ester resin (G) obtainable by polymerization of a vinyl-based monomer mixture (m3) comprising a methacrylic ester.

8. A thermoplastic resin composition comprising:

a graft copolymer (D) of claim 1 ;

a graft copolymer (F) obtainable by polymerization of a vinyl-based monomer mixture (m2) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of a cross-linked acrylic ester-type rubber polymer (E); and

a methacrylic ester resin (G) obtainable by polymerization of a vinyl-based monomer mixture (m3) comprising a methacrylic ester,

wherein the volume average particle diameter of the cross-linked ethylene.α-olefin copolymer (C) contained in the graft copolymer (D) in the thermoplastic resin composition is 0.2 to 0.6 μm,

the volume average particle diameter of the cross-linked acrylic acid ester-type rubber polymer (E) contained in the graft copolymer (F) in the thermoplastic resin composition is 0.05 to 0.18 μm, and

the amount of the cross-linked ethylene.α-olefin copolymer (C) is 15 to 85% by mass and the amount of the cross-linked acrylic ester-type rubber polymer (E) is 85 to 15% by mass, with respect to 100 parts by mass of the sum of the cross-linked ethylene.α-olefin copolymer (C) and the cross-linked acrylic ester-type rubber polymer (E).

9. A thermoplastic resin composition comprising:

a graft copolymer (D) of claim 1 ;

a graft copolymer (M) obtainable by polymerization of a vinyl-based monomer mixture (m5) in the presence of the composite rubber polymer (L) comprising a polyorganosiloxane (La); and

a methacrylic ester resin (G) obtainable by polymerization of a vinyl-based monomer mixture (m3) comprising a methacrylic ester,

wherein the volume average particle diameter of the cross-linked ethylene.α-olefin copolymer (C) contained in the graft copolymer (D) in the thermoplastic resin composition is 0.2 to 0.6 μm,

the volume average particle diameter of the composite rubber polymer (L) contained in the graft copolymer (M) in the thermoplastic resin composition is 0.05 to 0.18 μm, and

the amount of the cross-linked ethylene.α-olefin copolymer (C) is 15 to 85% by mass and the amount of the composite rubber polymer (L) is 85 to 15% by mass, with respect to 100 parts by mass of the sum of the cross-linked ethylene.α-olefin copolymer (C) and the composite rubber polymer (L).

10. The thermoplastic resin composition according to claim 9 , wherein the graft copolymer (M) is obtainable by polymerization of the vinyl-based monomer mixture (m5) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of a composite rubber polymer (L1) comprising the polyorganosiloxane (La) and a poly(meth)acrylic ester (Lb) that comprises a unit derived from a (meth)acrylic ester and comprises either one or both of a unit derived from a cross-linking agent and a unit derived from a graft cross-linking agent.

11. A molded article formed from the thermoplastic resin composition of claim 5 .

12. A thermoplastic resin composition comprising:

a graft copolymer graft copolymer obtainable by polymerization of a vinyl-based monomer mixture (m1) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of either an ethylene.α-olefin copolymer (A) which has a mass average molecular weight (Mw) of 17×10 4 to 35×10 4 and a distribution of molecular weight (Mw/Mn) of 1 to 3, which is represented by the ratio of the mass average molecular weight (Mw) and the number-average molecular weight (Mn), or a cross-linked ethylene.α-olefin copolymer (C) obtainable by cross-linking treatment of the ethylene.α-olefin copolymer (A);

a graft copolymer (F) obtainable by polymerization of a vinyl-based monomer mixture (m2) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of a cross-linked acrylic ester-type rubber polymer (E); and

a methacrylic ester resin (G) obtainable by polymerization of a vinyl-based monomer mixture (m3) comprising a methacrylic ester,

wherein the volume average particle diameter of the ethylene.α-olefin copolymer (A) or the cross-linked ethylene.α-olefin copolymer (C) contained in the graft copolymer (D) in the thermoplastic resin composition is 0.2 to 0.6 μm,

the volume average particle diameter of the cross-linked acrylic acid ester-type rubber polymer (E) contained in the graft copolymer (F) in the thermoplastic resin composition is 0.05 to 0.18 μm, and

the amount of the ethylene.α-olefin copolymer (A) or the cross-linked ethylene.α-olefin copolymer (C) is 15 to 85% by mass and the amount of the cross-linked acrylic ester-type rubber polymer (E) is 85 to 15% by mass, with respect to 100 parts by mass of the sum of the ethylene.α-olefin copolymer (A), the cross-linked ethylene.α-olefin copolymer (C) and the cross-linked acrylic ester-type rubber polymer (E).

13. A thermoplastic resin composition comprising:

a graft copolymer graft copolymer obtainable by polymerization of a vinyl-based monomer mixture (m1) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of either an ethylene.α-olefin copolymer (A) which has a mass average molecular weight (Mw) of 17×10 4 to 35×10 4 and a distribution of molecular weight (Mw/Mn) of 1 to 3, which is represented by the ratio of the mass average molecular weight (Mw) and the number-average molecular weight (Mn), or a cross-linked ethylene.α-olefin copolymer (C) obtainable by cross-linking treatment of the ethylene.α-olefin copolymer (A);

a graft copolymer (M) obtainable by polymerization of a vinyl-based monomer mixture (m5) in the presence of the composite rubber polymer (L) comprising a polyorganosiloxane (La); and

a methacrylic ester resin (G) obtainable by polymerization of a vinyl-based monomer mixture (m3) comprising a methacrylic ester,

wherein the volume average particle diameter of the ethylene.α-olefin copolymer (A) or the cross-linked ethylene.α-olefin copolymer (C) contained in the graft copolymer (D) in the thermoplastic resin composition is 0.2 to 0.6 μm,

the volume average particle diameter of the composite rubber polymer (L) contained in the graft copolymer (M) in the thermoplastic resin composition is 0.05 to 0.18 μm, and

the amount of the ethylene.α-olefin copolymer (A) or the cross-linked ethylene.α-olefin copolymer (C) is 15 to 85% by mass and the amount of the composite rubber polymer (L) is 85 to 15% by mass, with respect to 100 parts by mass of the sum of the ethylene.α-olefin copolymer (A), the cross-linked ethylene.α-olefin copolymer (C) and the composite rubber polymer (L).

14. The thermoplastic resin composition according to claim 13 , wherein the graft copolymer (M) is obtainable by polymerization of the vinyl-based monomer mixture (m5) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of a composite rubber polymer (L1) comprising the polyorganosiloxane (La) and a poly(meth)acrylic ester (Lb) that comprises a unit derived from a (meth)acrylic ester and comprises either one or both of a unit derived from a cross-linking agent and a unit derived from a graft cross-linking agent.