Polyorganosiloxane-containing graft copolymer, thermoplastic resin composition, and molded product

1. A polyorganosiloxane-containing graft copolymer obtained by polymerizing a grafting vinyl monomer (b) in the presence of a rubber (A) comprising a polyorganosiloxane (A1) and a vinyl polymer (A2), wherein the rubber (A) has an index of refraction in a range of 1.47 to 1.56, and a volume-average particle size of in a range of 300 nm to 2000 nm.

2. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein the rubber (A) is a composite rubber comprising the polyorganosiloxane (A1) and the vinyl polymer (A2).

3. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein the polyorganosiloxane (A1) is obtained by polymerizing an organosiloxane mixture comprising an organosiloxane, where the organosiloxane is a cyclic dimethylsiloxane and/or a difunctional dialkyl silane compound.

4. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein the rubber (A) has a volume-average particle size in a range of 400 nm to 1000 nm.

5. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein the polyorganosiloxane (A1) is present in the rubber (A) in a range of 40 mass % to 80 mass %, and the vinyl polymer (A2) is present in a range of 60 mass % to 20 mass %.

6. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein the vinyl polymer (A2) is obtained by polymerizing a vinyl monomer (a2) for rubber using a free-radical polymerization initiator having a solubility of 5 mass % or less in water at 20° C.

7. The polyorganosiloxane-containing graft copolymer of claim 6 , wherein the free-radical polymerization initiator is at least one selected from the group consisting of cumene hydroperoxide, diisopropyl benzene hydroperoxide, p-menthane hydroperoxide, t-butyl peroxy neodecanoate, t-butyl peroxyneoheptanoate, t-butyl peroxytrimethylacetate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethyl hexanoate, 2,2′-azobisisobutyronitrile, dimethyl 2,2′-azobis(2-methylpropionate), 2,2′-azobis (2,4-dimethylvaleronitrile), and 2,2′-azobis (2-methylbutyronitrile).

8. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein the vinyl polymer (A2) comprises an aromatic vinyl monomer unit and/or an aryl (meth)acrylate unit having an ester group that is a phenyl group or a substituent phenyl group.

9. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein the rubber (A) contains 0 mass % to 35 mass % of an alkyl (meth)acrylate unit based on a total of 100 mass % of the rubber (A).

10. The polyorganosiloxane-containing graft copolymer of claim 6 , wherein the vinyl monomer (a2) for rubber contains 0.1 mass % to 10 mass % of a crosslinking monomer based on a total of 100 mass % of the vinyl monomer (a2) for rubber.

11. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein the grafting vinyl monomer (b) comprises at least one selected from the group consisting of an aromatic vinyl monomer, an alkyl (meth)acrylate, a vinyl cyanide monomer, and an aryl (meth)acrylate having an ester group that is a phenyl group or a substituent phenyl group.

12. The polyorganosiloxane-containing graft copolymer of claim 1 , wherein a polymer obtained by polymerizing the grafting vinyl monomer (b) has an index of refraction in a range of 1.50 to 1.60.

13. A thermoplastic resin composition comprising the polyorganosiloxane-containing graft copolymer of claim 1 and a thermoplastic resin.

14. The thermoplastic resin composition of claim 13 , wherein the polyorganosiloxane-containing graft copolymer is present in a range of 0.5 mass % to 90 mass % based on a total of 100 mass % of the thermoplastic resin composition.

15. The thermoplastic resin composition of claim 13 , wherein the thermoplastic resin is a polycarbonate resin.

16. A molded product obtained by molding the thermoplastic resin composition of claim 13 .