Process for chlorinating ethylene polymers

Claim 1

A process for chlorinating solid, finely divided high density ethylene polymers in bulk, which consists essentially in contacting a solid, finely divided high density ethylene polymer with chlorine gas in the absence of solvents and/or suspension agents in two stages while maintaining the temperature in the first stage below the crystalline melting point of said polymer, and conducting the second stage at a temperature above the said crystalline melting point, and wherein the time of operation of said first stage is sufficient to prevent sintering together and/or discoloration of the polymer particles in the second stage, and wherein said high density ethylene polymer has at the most 5 mol.-% of a second α-alkene of from 3 to 8 carbon atoms copolymerized therewith, has a density of between about 0.930 and 0.970, has a melt index of at most about 5, has a particle size distribution between from about 50 to about 2000μ, has a porosity of at most about 0.15 cm 3 /g, has a BET surface area of at most about 1 m 2 /g, and has a wax content of at most about 1% by weight.