GB1014513A - Production of polymers of ethylene - Google Patents

Abstract

Ethylene, together optionally with an ethylenically unsaturated monomer, is polymerized at elevated temperature and pressure, e.g. 40-400 DEG C. and 5000-60,000 p.s.i., in the presence of a free radical catalyst in an elongated reactor in which the reaction mixture is cyclically circulated, ethylene and catalyst are fed separately or together into the reactor and ethylene polymer is recovered from the withdrawn reaction mixture. The ethylene may be copolymerized with ethyl acrylate, vinyl propionate or acetate, propylene butene-1, acrylonitrile or vinyl chloride. The reaction mixture may be circulated from a point in the reactor where the temperature is above the polymerization initiation temperature to at least one point upstream in the reactor where the reaction mixture is subjected to further polymerization; from a point where the polymerization rate has passed the maximum to a point upstream in the reactor where the ethylene has not yet reached the maximum; from a point at or adjacent to the exit of the reactor to a point upstream where polymerization occurs; from a point to another point in the reactor at which the pressure is higher than at the point of removal; or from a point in the reactor to the inlet of the reactor where feed ethylene at - 100 DEG C. to 100 DEG C. is also introduced. The free radical catalyst may be oxygen or a peroxygen compound, e.g. lauryl peroxide or di-tert.-butyl peroxide.