PURPOSE: To provide tubes for curing the self-peelable rubber which is useful for production of pneumatic tires by admixing a butadiene-acrylonitrile copolymer, an epichlorohydrin polymer or a specific graft copolymer to rubber.

CONSTITUTION: A graft copolymer A which is obtained by melt-mixing A1: 100 pts.wt. of brominated p-methylstyrene-isobutylene copolymer, ethylene- propylene terpolymer, hydrogenated polybutadiene and/or hydrogenated styrene- butadiene rubber with A2: 2 to 100 pts. wt. of a polar polymer comprising a variety of polyethers a polyester from a cyclic lactone or a polycarbonate obtained by reaction of phosgene with glycols, under shearing at 50 to 180°C or (B) a butadiene-acrylonitrile copolymer or (C) an epichlorohydrin polymer or copolymer is admixed to a rubber admixture to give a self-peelable tube or sleeve for curing which is useful for production of pneumatic tires.