Patent ID: 6998088

Claim:
An expandable curing bladder for use in curing rubber products is composed of a rubber composition comprised of, based on parts weight per 100 parts by weight rubber (phr): (A) an isobutylene copolymer rubber selected from butyl rubber and/or halobutyl rubber, and (B) about 0.5 to about 40 phr of a dispersion contained therein of micro-capsules comprised of a micro-encapsulated lubricant; wherein said butyl rubber is comprised of 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 which is comprised of a chlorinated or brominated copolymer of isobutylene and isoprene which contains from about 0.5 to about 5 weight percent units derived from isoprene; and wherein said micro-capsules are comprised of said lubricant which is micro-encapsulated within a thin walled shell of an organic polymer.