Abstract:
1,146,653. Self-extinguishing polymeric compositions. BADISCHE ANILIN- & SODAFABRIK A.G. 7 July, 1966 [9 July, 1965], No. 30552/66. Headings C3C and C3P. A self-extinguishing composition consists of (a) a normally solid thermoplastic polymer of at least 50% by wt. of styrene which may be substituted, and less than 50% of at least one other copolymerizable compound having the group having intimately incorporated therewith (b) an organic bromide, having a plurality of bromine atoms attached to carbon atoms and the bromine atoms constituting more than 40% of the bromide, in such an amount that the composition has a bromine content of 0À1-5%, and (c) 0À01-5% of (a) of a polymer which is prepared from (i) a compound of formula where R 1 , R 2 , R 4 and R 5 are H, halogen or a C 1-4 aliphatic hydrocarbon radical and at least two of the above Rs are where R 7 is a C 1-4 linear aliphatic hydrocarbon radical and R 8 is H or R 7 , and R 3 and R 6 are H or halogen atoms; or (ii) a mixture of the above compounds and a compound of the same formula where R 1 is where R 7 and R 8 are as before and the remaining Rs are H or halogen atoms. The (a) polymer may be polystyrene, a copolymer of styrene and acrylonitrile together with optionally polybutadiene, or a polymer obtained by polymerizing styrene in the presence of polybutadiene. Polymer (c) may be prepared by dehydropolymerization of p- or m-diisopropylbenzene with optionally isopropylbenzene, or 1,2,4-tri- or 1,2,4,5-tetra-isopropylbenzene. The bromide (b) may be hexabromocyclododecane or tris - (2,3 - dibromopropyl) - phosphate. The composition may be made by dissolving the three components in methylene chloride or by extruding the three components, with optionally kaolin; or by polymerizing styrene in the presence of an aq. mixture of polyvinylpyrrolidone, sodium pyrophosphate, benzoyl peroxide and the above (b) and (c) components. The composition may also contain a foaming agent, e.g. pentane or methyl chloride, and may be formed into a foamed sheet or strand.