Foamable, finely-divided, non-agglutinating, polystyrene - moulding cpds - by coating the polymer with a water-soluble salt of

摘要

A styrene (polymer moulding cpd. contg. foaming agent is coated with 0.005 - 0.5% w.r.t. wt. of moulding cpd. of a water-soluble salt of an N-substd. partial amide of a copolymer of an unsatd. aliphatic 4-6C polycarboxylic acid with a 2 - 8C comonomer, the degree of polymn. of the copolymer being 2 - 5000, pref. 50 - 500, e.g. the N,N-dimethyltrimethylenediamine semiamide of a 1 : 1 ethylene/maleic anhydride copolymer. PS foamable cpds. thus treated do not lump together in pre-foaming stage but show good sintering and mechanical strength on subsequent foaming/moulding.