Patent ID: 7550539

Claim:
A chlorosulfonated ethylene copolymer composition comprising at least one chlorosulfonated ethylene copolymer having 0.5 to 10 weight percent chlorine, 0.25 to 5 weight percent sulfur, based on total weight of said chlorosulfonated ethylene copolymer, and a plurality of —SO 3 M groups, wherein M is a cation, and wherein said chlorosulfonated ethylene copolymer is produced from a linear olefin copolymer comprising copolymerized units of 45 to 80 weight percent ethylene and 55 to 20 weight percent, based on total weight of said linear olefin copolymer, of an alpha-olefin having 3 to 20 carbon atoms, said linear olefin copolymer having a ratio of Mw/Mn less than 3.5.