process for the preparation of a fijnverdeelde blaasmiddelsamenstelling and method for the manufacture of schuimvormige objects from thermoplastic polymers under application of thisschuimmiddelsamenstelling derived.

摘要

1450057 Azodicarbonamide/silica blowing agents FISONS Ltd 21 Nov 1973 [7 Dec 1972] 56562/72 Heading C3C A blowing agent composition comprises azodicarbonamide and a silica having a BET (Brunauer, Emmett and Teller) surface area of 50-400 m.SP2/SP/g. and an available water content (determined by heating for 4 hours at 500‹ C.) of 2-20% by wt., the ratio of azodicarbonamide to silica being such as to provide 1À5-20 parts by wt. of available water to 100 parts by wt. of azodicarbonamide. The blowing agent is used to expand thermoplastic polymers, e.g. an olefine, styrene or vinyl chloride polymer. The blowing agent may also contain another compound containing available water, e.g. a metal silicate or a hydrate of calcium chloride, oxalate sulphate, carbonate, oxide, hydroxide or tartrate; magnesium sulphate, orthophosphate, hydroxide or benzoate; potassium carbonate; copper, zinc or ferric sulphate; borax; or barium or aluminium hydroxide.