| 摘要 |
1. A continuous process for the manufacture of ethylene homopolymers or copolymers of ethylene with at least one alpha-olefin having from 3 to 8 carbon atoms, successively comprising : a) a first step for (co)polymerizing ethylene at a temperature between 180 and 320 degrees C, under a pressure between 300 and 2 500 bars, in the presence of a catalytic system comprising on the one hand at least one halogenated compound of a transition metal of groups IVa to VIa of the Periodic System and on the other hand at least one activator selected from hydrides and organo-metallic compounds of metals of groups I to III of the Periodic System, the molar ratio of the activator to the transition metal compound being between 1 and 10, b) a second-step for separating the (co)polymer formed from the unreacted monomer(s), under a pressure of between 100 and 500 bars, c) a third step for recycling the unreacted monomer(s), and d) a fourth step for recompression up to the (co)polymerisation pressure, characterized by introducing into the reaction mixture, at the end of the first step, at least one compound selected from monoketones having from 3 to 10 carbons atoms, diketones having from 4 to 11 carbon atoms, monoalcohols having from 1 to 14 carbons atoms, polyalcohols having from 2 to 10 carbon atoms, and water. |
