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.

Uses

Chlorinated rubber is used for rust and corrosion prevention of steel products. It is widely used in anti-corrosion coatings and various strong adhesives. It can also be used as an impact modifier, permanent plasticizer, cold-resistant additive for polyethylene plastics, flame retardant for polyolefins, and modifier for various rubber compounds.

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.