Patent ID: 7572389

Claim:
A process for the preparation of a stabiliser composition for halogen-containing polymers, comprising the step of reacting an aqueous solution comprising water and one or more salts of a halogen-containing oxy acid of the general formula M(ClO 4 ) k , wherein M is Li, Na, K, Mg, Ca, Sr, Zn, Al, La, Ce, or an ammonium cation of the general formula NR 4 + , the radicals R are each independently of the others H or a linear or branched alkyl radical having from 1 to about 10 carbon atoms and k, according to the valency of M, is the number 1, 2, or 3, with at least one anhydride selected from the group consisting of inorganic acid anhydrides, organic acid anhydrides, inorganic base anhydrides, and mixtures thereof, in an exothermic reaction, to form a solid product comprising (1) the reaction product of water from the aqueous solution and the at least one anhydride and (2) one or more salts of the halogen-containing oxy acid in the form of crystallites, wherein less than 10% by weight of the crystallites of the one or more salts of the halogen-containing oxy acid have a crystallite size greater than 3 μm, based on the total content of the one or more salts of the halogen-containing oxy acid in the solid product.