Chlorobutyl Rubber (CIIR)

Chlorobutyl rubber, often abbreviated as CIIR, is a type of synthetic rubber derived from the copolymerization of isobutylene with a small amount of chloroprene (2-chloro-1,3-butadiene). This combination gives chlorobutyl rubber its distinctive properties, which make it suitable for a variety of applications.

• Structure:Chlorobutyl rubber is similar to butyl rubber (IIR) in structure, but with the addition of chlorine atoms introduced by the chloroprene monomer. This chlorination imparts certain desirable characteristics to the rubber.
• Impermeability:Similar to butyl rubber, CIIR exhibits excellent impermeability to gases and liquids, making it suitable for applications requiring containment or isolation from external elements.
• Heat Resistance:Chlorobutyl rubber typically has better heat resistance compared to standard butyl rubber. This property makes it suitable for applications where exposure to high temperatures is a concern.
• Low Gas Permeability:Like butyl rubber, CIIR has low gas permeability, which makes it suitable for applications requiring gas barrier properties, such as inner liners for tubeless tires.
• Chemical Resistance:Chlorobutyl rubber exhibits good resistance to a wide range of chemicals, oils, and solvents. This makes it suitable for applications in industries where exposure to such substances is common.
• Vulcanization: Chlorobutyl rubber can be vulcanized to improve its mechanical properties, such as tensile strength, elongation, and tear resistance. Vulcanization involves the cross-linking of polymer chains using sulfur or other vulcanizing agents.
• Applications:Chlorobutyl rubber finds applications in various industries, including automotive, pharmaceuticals, construction, and industrial manufacturing. Some common applications include tire inner liners, pharmaceutical stoppers, seals, gaskets, hoses, and roofing membranes.
• Manufacturing Processes:Chlorobutyl rubber is typically produced through the copolymerization of isobutylene with chloroprene using solution or suspension polymerization techniques. The resulting polymer can be further processed and compounded to meet specific application requirements.

Overall, chlorobutyl rubber (CIIR) offers a balance of impermeability, heat resistance, chemical resistance, and mechanical properties, making it suitable for a wide range of applications where these properties are essential. It is often chosen for applications where standard butyl rubber may not provide adequate heat resistance or chemical resistance.