Butyl Rubber (IIR) is a synthetic rubber best known for its exceptional air impermeability and water resistance, which are considered its core performance advantages. In addition, it offers a range of other outstanding physical and chemical properties, making it a widely used industrial elastomer.
Outstanding Air and Water Tightness
One of the most important butyl rubber properties is its extremely low permeability. The air permeability of butyl rubber is only about one-seventh that of natural rubber, while its water vapor permeability is as low as one-two-hundredth of natural rubber.
Thanks to this excellent sealing performance, Butyl Rubber (IIR) is an ideal material for tire inner liners and inner tubes, pharmaceutical rubber stoppers, airtight layers, and waterproof construction materials, where strict air and moisture barriers are required.
Heat Resistance and Aging Resistance
Butyl rubber features a highly stable molecular structure, allowing it to operate continuously at temperatures below 130°C. It exhibits excellent heat resistance, ozone resistance, and weather aging resistance, and is not easily degraded by oxidation or long-term environmental exposure. These characteristics contribute to the long service life of IIR rubber products in demanding applications.
Chemical Resistance
Butyl Rubber (IIR) shows good resistance to a wide range of chemicals, including acids, alkalis, and solvents. It also performs well in contact with polar media such as vegetable and animal oils, making it suitable for use in corrosive chemical environments and industrial sealing applications.
Electrical Insulation and Vibration Damping
In addition to its sealing performance, butyl rubber offers good electrical insulation properties and effective vibration and shock absorption. This makes it suitable for anti-vibration materials, electrical insulation components, and protective rubber parts.
Additional Characteristics and Limitations
Butyl rubber also features low water absorption, good low-temperature flexibility (with a glass transition temperature of approximately −70°C), and radiation resistance. However, it has certain limitations, including relatively low elasticity, slow vulcanization speed, and limited compatibility with some other rubber types.