RAW MATERIALS FOR TYRES

Rubber


In its natural form (without any additives), natural as well as synthetic




rubber is useless as its consistency varies with temperature and its elasticity is lost in


prolonged tension. Thus the need for additives. Natural rubber usually comes in the form


of “ribbed smoked rubber sheets” in weights of 30-110kg

Synthetic rubber is used as a substitute for natural rubber. Historically, one



of the first synthetic variants was “Methyl-rubber” produced in Germany during the


1914-18 war. The raw materials used were coal and limestone (Germany, Russia). Others


experimented with other raw materials such as alcohol (U.S.A, Italy, Russia), petroleum


(U.S.A, Russia) and natural gas (Germany). A major breakthrough in synthetic rubber


evolution was the development of Buna S 3 during the 1939-45 war by Germany. On the


other hand in U.S.A, the variants were GR-S, Neoprene, Butyl rubber and GR-N (Buna


N). These synthetic variants virtually made the production of tyres possible without the


use of any natural rubber.


Natural rubber, styrene butadiene rubber(SBR) and polybutadiene rubber(BR) are


primarily used for tread and sidewalls. On the other hand butyl and halobutyl rubbers are


used in inner liners.


Synthetic rubber has some advantages over natural rubber in terms of physical


properties such as wear and abrasion resistance but there is no perfect synthetic


alternative to natural rubber. Nowadays synthetic rubber comes as oil-inclusive (paraffin


or aromatic oil), staining/non-staining, acrylonitrile based, styrene based and so on.