This invention relates to an expandable curing bladder for use in curing rubber products; the bladder comprising an inner layer and an outer layer bonded to the first layer;the inner layer comprising a rubber composition comprised of, based on parts weight per 100 parts by weight rubber (phr): an isobutylene copolymer rubber selected from butyl rubber and/or halobutyl rubber,wherein said butyl rubber comprises a copolymer of isobutylene and isoprene which contains from about 0.5 to about 5 weight percent units derived from isoprene;wherein said halobutyl rubber is a halogenated butyl rubber comprises a chlorinated or brominated copolymer of isobutylene and isoprene which contains from about 0.5 to about 5 weight percent units derived from isoprene; andthe outer layer comprising a rubber composition comprising a silicon rubber.