Abstract:
A self-extinguishing composition comprises (a) a styrene polymer, (b) an organic chlorine or bromine compound used in such amount that the chlorine content of the composition is 3-10% or the bromine content is 1-5%, and (c) 0.05-5% of a metal chelate compound of a metal of Groups Ib, IIb, IVb, Va, VIb, VIIb or VIII of the Periodic Table. The polymer may be polystyrene or a styrene copolymer containing at least 50 mol. per cent styrene and acrylonitrile, an ester of acrylic or methacrylic acid with a C1- 8 alcohol, vinyl carbazole, butadiene or 0.01-0.5% divinylbenzene. The chelate compound may be an acetylacetonate of copper, zinc, mercury, titanium, chromium, molybdenum, manganese, iron or cobalt, ethyl acetoacetate and copper, nickel salicylaldehyde, chromium anthranilate, or may be one of the said metals and a b-diketone, a b-ketocarboxylic ester, a hydroxyaldehyde or an aminocarboxylic acid. The organic chlorine compound may be a chlorinated diphenyl. The composition may also contain 2-20% of an expanding agent, e.g. a gaseous or liquid hydrocarbon or chlorofluorohydrocarbon. In an example, styrene is bead polymerized in water with polyvinylpyrrolidone, a chlorinated paraffin, pentane and a chelate compound, to produce a foam; styrene is polymerized in petroleum ether with hexabromocyclododecane and the chelate compound; films are prepared from a solution of the composition in methylene chloride and are then expanded.