Chlorinated rubber

Chemical properties

Chlorinated rubber is typically prepared by treating a solution of masticated natural rubber in chloroform or carbon tetrachloride with chlorine at 80-100°C until sampling indicates the product has a chlorine content of about 65%. During this time, hydrogen chloride is evolved. After the passage of chlorine has been stopped, the solution is refluxed until the evolution of hydrogen chloride ceases; this results in a product of good stability. The chlorinated rubber is then isolated by precipitation with methanol.

Definition

An elastomer (natural rubber or a polyolefin) to which 65% of chlorine has been added to give a solid, film-forming resin. White, amorphous powder available in viscosity grades from 5 to 125 c P, the figures indicating vis- cosity of a 20% solution in tol

Preparation

The reaction of natural rubber and chlorine is complex and possibly involves the following sequence￡o

Hazard

Do not dry-mill chlorinated rubber with zinc oxide; mixture reacts violently at 216C. Do not use in baked enamels.