GB627376A - Improvements in or relating to the production of chlorinated polythene - Google Patents

Abstract

Chlorinated polythene is made by polymerizing ethylene at p elevated temperature and pressure, ejecting the polythene into cooling water at substantially atmospheric pressure, preparing from it uncompacted polythene of particle size less than 36 B.S. mesh, suspending it in water and passing chlorine gas through the suspension maintained at 40-100 DEG C. in a state of agitation. The suspension is preferably irradiated with actinic light of wavelength 2800-5500 A. At least 9 parts of water to 1 part of polythene is preferably used and 25-30 parts of water if a product having more than 45 per cent by weight of chlorine is to be prepared. The suspension is improved by the presence of a small amount of a wetting agent, e.g. sodium lauryl sulphate, and of calcium chloride. The ethylene may be polymerized in the presence of water, benzene or chlorbenzene, oxygen and an alkali at a pressure of 500-1500 atmos. and at 150-275 DEG C. On ejecting the polymer at atmospheric pressure, the liquids expand the polymer leaving it in a porous, spongy form. If necessary, the polythene is then comminuted and screened to the desired particle size. The chlorinated polythene should be washed with distilled water which may contain anti-acids and anti-chlors. The products may be made into films, sheets, tubes and filaments for use in luggage articles, raincoats and food coverings, and are useful in electrical and mechanical applications. They may also be used as impregnants, e.g. in solution in volatile chlorinated solvents, for fabrics for fungi, water and fire protection. Valuable blends are also produced by mixing with synthetic linear polyamides and with vinyl acetate and vinyl chloride polymers. Specifications 576,119 and 592,487 are referred to.