| 摘要 |
Wax-like ethylene polymers of low molecular weight and predominantly linear are prepared by the thermal decomposition of ethylene polymers of high molecular weight and to some extent ramiform, said decomposition being carried out in an atmosphere free of air and oxidizing agents, the polymer to be decomposed being mixed with a melt of already decomposed ethylene polymer, and the decomposition being then carried out at 300 DEG to 600 DEG C. for 30 seconds to 5 hours. The process may be applied to ethylene homopolymers and copolymers, batchwise or continuously, and radical forming agents and molecular weight regulators may be added before or during the decomposition. The process may be effected in a stirred vessel in the lower part of which may be a coiled flow pipe through which the product may be withdrawn and passed to a granulating device. Examples describe the preparation of waxes from (1, 4 and 6 to 9) polyethylene, (2) an ethylene/vinyl acetate copolymer, (3) polyethylene in the presence of dicumyl peroxide, and (5) an ethylene/carbon monoxide copolymer. The products may be used in polishes and for coating paper. |
