Stabiliser compsn. for chlorine-contg. polymers - comprises mixt. of tri:basic lead sulphate and alkaline earth metal fillers

摘要

Compsn. comprises a homogeneous mixt. contg. (A) super fine granular tribasic lead sulphate having a number ave. short dia 0.2 mu and a bulk specific gravity 1.8 g/ml and (B) alkaline earth metal fillers in wt. ratio of (A):(B) of 95:5-30:70. (A) is synthesised by reaction of lead monooxide produced by the wet method and sulphuric acid in the presence of water. Pref. the tribasic lead sulphate grains are coated with metal salts of higher fatty acids in aq. slurry in order to improve dispersibility and prevent coagulation. Coating of tribasic lead sulphate is effected by adding an ammonium salt or alkali metal salt of higher fatty acid in amt. 0.1-25wt. % of tribasic lead sulphate to the aq. slurry of tribasic lead sulphate. (B) includes calcium carbonate, calcium silicate, asbestos powder, talc, magnesium oxide, Pref. (B) has a number ave. grain dia. of 50-0.01 mu.