Hydrogenated copolymer rubber, rubber composition comprising said rubber, and rubber product obtained from the rubber

A hydrogenated copolymer rubber which is a hydrogenation product of a random copolymer rubber consisting of: (A) 30-70 mole % of a unit derived from at least one monomer selected from the group consisting of alkyl acrylates and alkoxy-substituted alkyl acrylates,(B) 20-70 mole % of a unit derived from at least one conjugated diene, and(C) 0-10 mole % of a unit derived from at least one other ethylenically unsaturated compound copolymerizable with the components (A) and (B) [(A) + (B) + (C) = 100 mole %] wherein at least 90% of the double bonds of the conjugated diene unit is hydrogenated; a crosslinkable rubber composition comprising said hydrogenated copolymer rubber and a crosslinking agent; and a thermoplastic polymer comprising said hydrogenated copolymer rubber and a thermoplastic resin. These rubbers and compositions are superior in low-temperature resistance, heat resistance, ozone resistance, mechanical strengths, compression set, impact resilience and oil resistance.