seen framstella skumplaster from polyvinyl chloride or polyethylene by peroxidisk rymdfornetning and uppskumning by chemically blasmedel in nervaro of alumina or silica utfelld

摘要

1498823 Foamed cross-linked shaped polymers BAYER AG 19 Dec 1974 [21 Dec 1973] 54904/74 Heading C3C Foamed, cross-linked polymers based on an α,# - monoolefinically unsaturated monomer are made from a mixture of 0À01-10% by wt. of silica or a derivative thereof, the polymer, a blowing agent and a peroxide by shaping the mixture at a temperature below the decomposition point of the peroxide and then foaming and cross-linking by heating to at least 190‹ C. The silica may be pyrogenic or precipitated silica. In the examples a mixture of (1) polyethylene, azodicarbonamide and silicic acid is granulated, mixed with polyethylene and dicumyl peroxide and made into a bond and (2) azodicarbonamide, and sodium silicate and (3) silica and azodicarbonamide are used to foam cross-linked polyethylene as in (1) by heating in a furnace. The polymer may also be polystyrene, polyvinyl chloride, polypropylene or ethylene/vinyl acetate copolymer.