Exxon™ butyl rubber    
Butyl rubber is a copolymer of isobutylene and a small amount of isoprene providing for a highly saturated backbone. The primary properties of butyl rubber are excellent air-barrier performance, good flex fatigue and vibration damping.        
Properties            

• Low permeability to air, gases and moisture
• Vibration damping
• Low glass transition temperature
• Low modulus elastomer
• Low compression set
• Resistance to aging and to weathering from atmospheric exposure
• Wide vulcanization versatility
• Fast cure rates
• Processing safety: no nitrosamines or nitrosamines precursors Benefits of high extensibility
• Broad range of durometer and tensile strength properties
• Low filler content for specific gravity, cost-effective compounding