Polymerization of propylene with a catalyst prepared in situ

Claim 1

In the method of producing elastomeric polymers of propylene and up to about 5 mole % of another α-olefin by the polymerization of propylene in the presence of a catalyst system which is the reaction product of a metal oxide and an organometallic compound of the formula (RCH 2 ) 4 M, where M is Zr, Ti or Hf; R is aryl, aralkyl, tertiary alkyl or trialkylsilyl; the aforementioned alkyl groups are C 1 -C 12 ; and the RCH 2 group has no hydrogen bonded to the carbon which is beta to M; at a temperature of 20° to 100° C. and a pressure of 147 psi up to 5000 psi (0.1-34.5 MPa) such that the reaction medium contains liquid propylene, the improvement which comprises mixing the components of the catalyst system together, whereby they react to form said catalyst system, in a solvent consisting principally of liquid propylene and the elastomeric polymer is produced as a mobile slurry in said liquid propylene.