Butyl (IIR) rubber parts
Butyl rubber is a copolymer of isobutylene with a small amount of isoprene. Gases and moisture pass through it far more slowly than through most rubbers. That is why it is used for bladders, diaphragms and seals that must hold vacuum or pressure.
It also damps vibration well and resists weather and many dilute chemicals. It swells in petroleum oils and fuels.
At a glance
| Property | Butyl (IIR) |
|---|---|
| Also called | IIR, Isobutylene isoprene rubber |
| Known for | Gas impermeability |
| Typical service temperature | -40 °F to +250 °F (-40 °C to +121 °C) |
| Common ASTM D2000 type and class | AA, BA |
Typical values for general-purpose grades. The compound, the hardness and the service conditions decide what a part can take, so we confirm the compound with your quote. For what the type and class letters mean, see ASTM D2000 callouts.
Resistance profile
Generally good with
- Low gas and moisture permeability
- Vibration damping
- Weather and ozone
- Many dilute acids and alkalis
Usually a poor choice for
- Petroleum oils and fuels
- Hydrocarbon solvents
Where butyl is used
- Seals that hold vacuum or pressure
- Diaphragms and bladders
- Vibration and shock mounts
How we make butyl parts
We work in butyl with these processes, all under one roof in Canonsburg, Pennsylvania:
Butyl parts are made to your drawing. There are no stock butyl profiles in our catalog.
Quote a part in butyl
Send us a drawing, a sample part or a rough sketch. We will review it, recommend the right material and process, and give you a firm ship date with your quote.