Separate streams with different catalyst prior to combination

Claim 1

A process for grafting a polydiene or a polyalkenamer onto an unsaturated polyolefin rubber backbone, which comprises: a. dispersing in a first liquid stream a catalytically effective amount of a first organic solvent-soluble Ziegler-Natta metathesis catalyst component containing a metal of Subgroups V thru VII of the periodic table; b. dispersing in a second liquid stream separate from said first liquid stream a catalytically effective amount of a second organic solvent-soluble Ziegler-Natta metathesis catalyst component containing an alkyl or a hydride of a metal from Main groups I thru III of the periodic table; c. dispersing, separately or as a mixture, into one or both of said first and second liquid streams or into at least one further liquid stream (i) a polydiene or a polyalkenamer having at least one metathesisable double bond per molecule and (ii) an unsaturated polyolefin rubber comprising a metathesisable copolymer of two or more α-olefins with an unconjugated diolefin; and d. intensively intermixing said liquid streams under metathesis reaction condictions to form in situ a catalytic amount of a complete Ziegler-Natta metathesis catalyst system and to metathetically graft said polydiene or polyalkenamer onto said polyolefin rubber, thereby reducing side reactions between the catalyst components and the polymer components of said streams; and e. recovering the resultant graft copolymer characterized by an increased reduced specific viscosity as compared to the starting polymer and a low gel content.