| abstract |
The present invention relates to a process for polymerisation of ethylene, in particular a process which comprises using a catalyst system comprising comprising a catalyst system comprising: i) a solid catalyst comprising Ti, Mg and halogen, ii) a first activator which is at least one trialkylaluminium compound of the formula AIR 3 , where each R is independently a C2 to C20 alkyl radical, and iii) a second activator which is at least one alkylaluminium chloride of the formula AlR′ 2 Cl, where each R′ is independently a C2 to C20 alkyl radical, characterised in that the second activator is introduced directly in the polymerisation reactor, without precontact with the solid catalyst, continuously or semi-continuously and at a maximum rate of introduction at any time corresponding to less than 10 ppm by weight of chlorine relative to the rate of polyethylene production. |