GB546528A - Improvements in inflatable air-bags for use in tire vulcanization processes - Google Patents

Abstract

546,528. Hydrocarbon polymers ; inflatable air bags. STANDARD OIL DEVELOPMENT CO. Dec. 3, 1940, No. 17189. Convention date, Nov. 24, 1939. Addition to 540,285. [Class 2 (iii)] [Also in Group V] An inflatable air bag for use as a core in the vulcanization of tyres in a mould comprises a continuous sheet of a copolymer of an aliphatic mono-olefin, such as isobutylene, and a conjugated aliphatic diolefin, such as butadiene, isoprene, pentadiene-1.3, or 2.3-dimethylbutadiene. The copolymers may be prepared by the methods described in Specifications 513,521 and 523,248, 70 to 99.5 parts by weight of the iso-olefin being employed in admixture with 30 to 0.5 parts of the diolefin, and may be cured with sulphur. Inorganic fillers, e.g. calcene (a stearic acid treated powdered calcium carbonate), ferric oxide, magnesium oxide, or barytes, inorganic pigments, e.g. carbon black, and small proportions of organic fillers, e.g. wood flour, ground cork or cellulosic material may be incorporated in the copolymers. One or more layers of fabric may be incorporated in the air bag. In an example, a copolymer prepared from 80 parts of isobutylene and 20 parts of butadiene is compounded with calcene, zinc oxide, stearic acid, tetramethylthiuram disulphide, and sulphur, the mixture is shaped to form an air bag either by extrusion or by winding a strip of the sheeted mixture on a mandrel, and the air bag is cured by heat. Specification 543,308 also is referred to.