Butyl rubber has good chemical stability and thermal stability, most notably air tightness and water tightness. It is only natural rubber air permeability 1/7, 1/5 SBR, while vapor transmission rate was 1/200 of natural rubber, styrene-butadiene rubber 1/140. Therefore mainly used to produce butyl tape, tape, sealant and various inner tubes, steam pipes, water births, dam bottom, gaskets and other rubber products.