GB876074A - Rubber and plastic formulations and process - Google Patents

Abstract

Curable natural or synthetic resins, e.g. comprising natural, nitrile, or neoprene rubber, polyurethanes, polyvinyl chloride, incorporate a small amount, e.g. 1-3 parts per 100 parts by weight of resin, of an activated crystalline zeolitic molecular sieve material for absorbing undesirable and detrimental contaminants, e.g. hydrogen sulphide, hydrochloric acid, moisture, in the resin which cause pitting and discolouration in the final product. The activated zeolitic material is produced by heating a natural or synthetic zeolite to remove water of hydration, preferably under reduced pressure, until the water content is less than 5% by weight. Suitable synthetic zeolites include sodium, potassium, or calcium zeolite A, zeolite B, and zeolite T, whilst natural zeolites include erionite, chabazite, mordenite, and clino-ptilolite. The activated zeolitic molecular sieve material may be incorporated in curable resin compositions comprising a crystalline zeolitic molecular sieve loaded with a curing accelerator, e.g. piperidine, pyrocatechol, or a peroxide catalyst, e.g. ditertiarybutyl peroxide, for the purpose of absorbing impurities, e.g. moisture, in the resin, which would otherwise displace the adsorbed accelerator, &c., with disadvantageous results, e.g. premature vulcanization or scorching. Specifications 776,467 and 777,232 are referred to.