High-purity isobutylene is the backbone of butyl rubber — the material behind airtight tyre inner liners, seals and pharmaceutical closures.
Isobutylene (C₄H₈) is a reactive olefin best known as the main monomer in butyl rubber. Its structure gives the finished polymer an unusually low permeability to gases — the property that makes butyl rubber so useful.
From monomer to butyl rubber
Butyl rubber is made by copolymerising isobutylene with a small amount of isoprene. The result is an elastomer that is highly impermeable to air and moisture, chemically stable and resistant to ageing.
Because polymerisation is sensitive to impurities, high-purity isobutylene (typically greater than 99.5%) is required for consistent, high-quality rubber.
Why purity matters
Trace contaminants can interfere with polymerisation, affecting molecular weight and the final material's performance. Tight isobutylene specifications translate directly into predictable, reproducible rubber properties.
End uses
The airtightness of butyl rubber makes it the standard for tyre inner liners and inner tubes. It is also used in seals, gaskets, adhesives and pharmaceutical stoppers.
- Tyre inner liners and tubes
- Seals, gaskets and vibration damping
- Adhesives and sealants
- Pharmaceutical closures
Beyond rubber
Isobutylene is also used to produce MTBE, polyisobutylene and antioxidants — making it a versatile building block well beyond the tyre industry.