SULFUR-CONTAINING UNSATURATED HYDROCARBON POLYMER AND METHOD FOR PRODUCTION THEREOF, ADDITIVE FOR RUBBER, RUBBER COMPOSITION, AND TIRE

Provided is a sulfur-containing unsaturated hydrocarbon polymer which can improve wet grip performance and fuel efficiency of a tire in a well-balanced manner by being blended into a rubber composition for a tire. A sulfur-containing unsaturated hydrocarbon polymer of the present invention is a reaction product obtained by reacting sulfur with an unsaturated bond in a polymer of an unsaturated hydrocarbon.