Patent ID: 6096841
Filing Date: 2000-08-01
Classification: C08F,Y10S

Abstract:
A process for the polymerization of CH.sub.2 .dbd.CHR olefins in which R is hydrogen or an alkyl, cycloalkyl or aryl with 1-10 carbon atoms comprising:a) preparing a pre-polymer by polymerizing one or more olefins CH.sub.2 .dbd.CHR, in which R is hydrogen or an alkyl, cycloalkyl or aryl with 1-12 carbon atoms, and/or one or more di- or polyenes in the presence of a coordination catalyst, said coordination catalyst comprising the product obtained by contacting a compound of Ti, V, Zr or Hf with a magnesium halide, said magnesium halide being in the form of particles having crystallites with an average size below 300 .ANG., said magnesium halide being present in said pre-polymer in an amount of between 50 and 50,000 ppm;b) contacting said pre-polymer with the product of the reaction of a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-.pi. bond with an Al-trialkyl compound in which the alkyl groups have from 1 to 12 carbon atoms and linear or cyclic alumoxane compounds containing the repeating unit --(R.sub.4)AlO--, in which R.sub.4 is an alkyl group with 1-6 carbon atoms or a cycloalkyl or aryl group with 6-10 carbon atoms and containing from 2 to 50 repeating units; andc) under conditions effective to polymerize, adding the olefins of formula CH.sub.2 .dbd.CHR to the product of step b).