Chlorosulfonation of chlorinated polyethylene

Claim 1

An anhydrous process for preparing finely-divided, particulate chlorosulfonated polyethylene, the process comprising two sequential steps: A. providing a finely-divided, pulverulent, free-flowing chlorinated polyethylene starting material which is generally free of water and oxygen, the starting material (1) being prepared from high density polyethylene having a weight average molecular weight of from about 40,000 to about 300,000, and (2) having (a) a chlorine content of from about 20 to about 48 percent by weight of polymer, (b) a 100 percent modulus of from about 0.5 to about 4.8 Mega Pascals, and (c) a relative crystallinity of from about 0 to about 15 percent; and B. fluidizing the starting material with a gaseous mixture of sulfur dioxide and chlorine while said starting material is in the presence of chlorine free radicals, the gaseous mixture having a ratio of sulfur dioxide to chlorine of from about 1:1 to about 16:1, and the chlorine free radicals being generated by a means selected from the group consisting of ultraviolet light radiation having a wavelength sufficient to generate chlorine free radicals and chemical free radical initiators at a temperature within a temperature range of from about 20° to about 100° Centigrade and for a period of time sufficient to obtain chlorosulfonated polyethylene having a sulfur content of from about 0.8 to about 2.5 percent by weight of polymer and a chlorine content of from about 20 to about 50 percent by weight of polymer.