METHOD FOR PRODUCING GRAFT COPOLYMER, GRAFT COPOLYMER OBTAINED BY THE METHOD, RUBBER COMPOSITION CONTAINING THE GRAFT COPOLYMER, AND TIRE

Provided are a method of producing a graft copolymer, the method involving subjecting a radically polymerizable monomer to living radical graft polymerization with a rubber component formed of a natural rubber and/or a synthetic diene-based rubber in an aqueous medium in the presence of a polymerization control agent, a rubber composition containing the graft copolymer obtained by the method, and a tire obtained by using the rubber composition in any one of its tire members. Further provided are a method of efficiently producing a graft copolymer, the method involving subjecting a radically polymerizable monomer, in particular, a functional group-containing radically polymerizable monomer to living radical graft polymerization with the natural rubber and/or the synthetic diene-based rubber, a rubber composition containing the graft copolymer obtained by the method and excellent in, for example, low heat generating property, wear resistance, and fracture characteristic, and a tire obtained by using the rubber composition in any one of its tire members and having the above-mentioned properties.