- Exxon Butyl . . . Exxon Chemical
- Polysar Butyl . . . Bayer Polymer.
ASTM D1418 Designation: IIR
ASTM D2000/SAE J200 Type, Class: AA,BA
Apple Compound Designation: BU
Standard Color: Black
Description: An all-petroleum product, Butyl is a copolymer of isobutylene and isoprene and has largely been replaced by Ethylene Propylene since its introduction.
Key Use(s): Highly effective in vacuum sealing applications. Good seal for hydraulic systems.
Temperature Range: Standard Compound: -50° to +250°F.
Hardness (Shore A): 30 to 90
Features: With outstanding low permeability to gases, Butyl is especially effective in vacuum sealing applications. It also features good to excellent resistance to ozone and sunlight aging.
Butyl further features excellent shock dampening capabilities.
Only slightly affected by oxygenated solvents and other polar liquids, Butyl is often utilized in seals for hydraulic systems using synthetic fluids. It is good with MEK, and silicone fluids and greases.
Limitations: Because it is a petroleum product, Butyl has poor resistance to hydrocarbon solvents and oils, and diester-based lubricants.