Dependence of flame retardancy and smoke suppression properties of chloroprene rubber on zinc borate and antimony trioxide loadings

Chloroprene rubber (CR) is one of the widely used materials due to its excellent performance. However, it will evolve large amounts of smoke and toxic gas during its combustion, which may cause smoke inhalation even human deaths in the populated enclosed spaces like rail transit, etc. Aiming to improving the fire safety of CR, the effects of zinc borate (ZnB) and antimony trioxide (Sb 2 O 3 ) alone and their combination on the flame retardancy, smoke suppression, and toxicity inhibition of CR are investigated. The performances of CR/ZnB, CR/Sb 2 O 3 and CR/ZnB/Sb 2 O 3 were analyzed by limiting oxygen index (LOI), UL94 rating and cone data. The results showed that the combination of ZnB and Sb 2 O 3 can integrate their advantages to exhibit the higher LOI and flame retardancy index (FRI) values as well as toxicity inhibition ability, indicating their good fire retardancy feature. The corresponding mechanism including the flame retardant mechanism and Lewis acid function was discussed in detail.