Properties Natural S B R EPDM Neoprene Nitrile or Buna N Silicone Hypalon Urethane Tensile Strength Excellent Good Excellent Excellent Good Poor Excellent Excellent Hardness Range Shore A 30-100 30-100 25-80 15-80 17-100 40-70 40-75 22-45 Cast 30-85 Wrapped Tear Resistance Good Fair Good Good Fair Poor Fair Excellent Abrasive Resistance Excellent Excellent Good Excellent Good Fair Excellent Out- Standing Compression Set Good Good Good Fair-Good Good Good Fair Good Rebound: Natural S B R EPDM Neoprene Nitrile or Buna N Silicone Hypalon Urethane Cold Excellent Good Excellent Very Good Good Excellent Good Good at Room Temp Hot Excellent Very Good Excellent Very Good Good Excellent Good Poor at 50 degrees Dielectric Strength Excellent Excellent Excellent Good Poor Excellent Excellent Excellent Electric Insulation Good- Excellent Good- Excellent Good Fair-Good Poor Excellent Good Fair Permeability to Gases Fair Very Low Fair-Good Low Fair Good Low Fair Acid Resistance Dilute Fair-Good Fair-Good Good- Excellent Excellent Good Fair Very Good Poor Acid Resistance Concentrated Fair-Good Fair-Good Good- Excellent Good Good Fair Very Good Poor Solvent Resistance: Natural S B R EPDM Neoprene Nitrile or Buna N Silicone Hypalon Urethane Aliphatic Hydrocarbons Poor Poor Poor Good Excellent Poor Good Excellent Aromatic Hydrocarbons Poor Poor Poor Fair Good Poor Fair Good Oxygenated (Keytones & Acetates) Good Good Good Poor Poor Fair Poor Poor Laquer Solvents Poor Poor Good Poor Fair Poor Poor Poor Lubricating Oil Poor Poor Poor Good Very Good Good Good- Excellent Excellent Gasoline & Oil Poor Poor Poor Good Excellent Poor Good Excellent Vegetable Oils Poor-Good Poor Good Good Excellent Good Good Excellent Water Absorption Very Good Very Good Very Good Good Fair-Good Good Very Good Good at 70 degrees poor at 121 degrees Resistance to: Natural S B R EPDM Neoprene Nitrile or Buna N Silicone Hypalon Urethane Oxidation Good Good Excellent Excellent Good Excellent Excellent Excellent Ozone Fair Poor Excellent Excellent Fair Excellent Out- Standing Out- Standing Sunlight Aging Poor Fair Very Good Very Good Poor Excellent Out- Standing Good Heat Aging Good Excellent Excellent Excellent Excellent Excellent Excellent Good Flame Poor Poor Poor Good Poor Fair Good Good Heat Good Very Good Excellent Excellent Very Good Good Excellent Fair Cold Excellent Good Excellent Good Good Excellent Good Excellent Major Attributes Several Resistance to Abrasion General Purpose Oil Resistance Weatherability Oil Resistance Heat Resistance and Release Weatherability Abrasion Resistance