Knowledge and application of brominated butyl rubber

Brominated butyl rubber (BIIR) is a modified product of IIR. The purpose of modification is to improve the activity of IIR, improve its compatibility with unsaturated rubber, improve self-adhesive, mutual adhesive and co crosslinking ability, and maintain the original characteristics of IIR. The bromination of IIR not only increases the crosslinking position, but also enhances the reactivity of the double bond. This is because the bond energy of C-Br bond is smaller and the vulcanization reaction activity of brominated butyl rubber is higher, so it has faster vulcanization speed and stronger vulcanization adaptability, and has better co vulcanization performance with general rubber. Compared with ordinary butyl rubber, brominated butyl rubber has the following characteristics: (1) fast curing speed; (2) Good compatibility with natural rubber and styrene butadiene rubber; (3) The adhesive properties with natural rubber and styrene butadiene rubber are improved; (4) It can be vulcanized with zinc oxide alone (BIIR is the only elastomer that can be vulcanized with sulfur alone or zinc oxide), and the vulcanization methods are diversified; (5) It has good heat resistance.

With so many advantages, brominated butyl rubber is gradually replacing ordinary butyl rubber in a variety of application fields, such as radial tire, bias tire, sidewall, inner tube, container lining, medicine bottle stopper, machine liner and other industrial products. Brominated butyl rubber is an irreplaceable raw material for manufacturing tubeless tires and pharmaceutical products.

The preparation methods of BIIR include dry mixing bromination method and solution bromination method. The dry mixing bromination method is to mix N-bromosuccinimide, dibromodimethylhydantoin or activated carbon adsorbed bromine (mass fraction of 0.312) with IIR in an open mill to obtain BIIR; The solution bromination method is prepared by dissolving IIR in chlorinated hydrocarbon solvent and adding bromine with a mass fraction of about 0.03. The process is continuous and the product quality is uniform and stable. The optimal mass fraction of bromine in BIIR is 0.017-0.022.