What is butyl rubber (IIR)?

Butyl rubber (IIR, Isobutene Isoprene Rubber) is a synthetic rubber, which is characterised above all by its low gas permeability and very good chemical resistance. It is characterised by Copolymerisation of isobutylene with small amounts of isoprene. The low isoprene content enables the Vulcanisation, while the high isobutylene content is responsible for the dense, saturated polymer structure.

 

Properties of butyl rubber (IIR)

  • Very low air and gas permeability, ideal for gas and airtight applications
  • Excellent chemical resistance to many acids, alkalis and polar chemicals
  • High resistance to weathering, ozone and ageing without additives
  • Good electrical insulating properties, suitable for high-voltage applications
  • Temperature resistant from approx. -60 °C until +130 °C
  • High damping properties, reduces oscillations and vibrations
  • Limited oil and fuel resistance, therefore not suitable for media rich in mineral oil

 

Areas of application & material combinations of butyl rubber (IIR)

IIR is preferably used in products that need to be air or gas-tight. Typical applications include inner tubes for tyres, sealing membranes, pharmaceutical stoppers or protective films. In combination with halogenation (e.g. chlorobutyl, bromobutyl), adhesion to other materials can be improved, which makes it suitable for use in Rubber-plastic composite parts or as an inner layer in tyres.