Butyl rubber (IIR, CAS 9010-85-9) is a synthetic rubber produced by the copolymerization of isobutylene and a small amount of isoprene, offering excellent chemical and thermal stability with good performance in medium-temperature environments.It is not designed for extreme heat exposure, but it performs well in thermal aging resistance and air-tight sealing applications where long-term stability is required.
Heat Resistance of Butyl Rubber (IIR)
Temperature Range
Commercial butyl rubber typically operates within a temperature range of -40°C to 120°C. Within this range, the material maintains stable physical and mechanical properties.
As a saturated synthetic rubber, IIR (CAS 9010-85-9) has better thermal oxidation resistance than natural rubber, making it suitable for sealing parts, gaskets, and industrial rubber components used in moderate heat conditions.
Thermal Aging Performance
Butyl rubber compounds show good resistance to thermal aging. After continuous exposure at around 100°C for 72 hours, the material can retain most of its physical properties.
Thanks to its low gas permeability and stable polymer structure, butyl rubber is less prone to cracking, hardening, or deformation under sustained medium-temperature conditions. This makes it widely used in rubber sheets, molded parts, and sealing systems.
High Temperature Limit
Pure butyl rubber begins to show noticeable degradation when temperatures exceed 130°C. At higher temperatures, especially above 150°C, the material may lose elasticity and become harder.
For this reason, standard IIR is not recommended for continuous use in high-heat machinery or high-temperature pipeline systems.
Heat-Resistant Modified Butyl Rubber
Heat resistance can be improved through formulation adjustment. Modified butyl rubber compounds with heat-resistant fillers and anti-aging additives can extend the service temperature to around 135°C.
These upgraded materials are commonly used in:
- Industrial sealing systems
- Construction waterproof membranes
- Mechanical gaskets
- Customized rubber parts
Practical Application Guidelines
To ensure longer service life, butyl rubber components should not be exposed to continuous heat sources above 120°C for extended periods.
In practical use, butyl rubber performs best in:
- Moderate temperature environments
- Sealed or semi-enclosed systems
- Applications requiring long-term air tightness
Proper temperature control can significantly reduce thermal aging and extend material lifespan in industrial applications.