Patent ID: 7947786

Claim:
Continuous process for making an elastomer composition having a, Mooney Viscosity (ML (1+4) @125° C.) of from 16 to 180, the composition including a first polymer and a second polymer, the process comprising: polymerizing a first monomer system including propylene and optionally ethylene in a solvent using a first catalyst system in a first polymerization zone to provide a first polymer having 60 wt % or more units derived from propylene, including isotactically-arranged propylene-derived sequences and further having a heat of fusion less than 45 J/g or a melting point less than 105° C. or both and a Mooney Viscosity (ML (1+4) @125° C.) of from 1 to 45; polymerizing a second monomer system that includes ethylene and optionally an alpha-olefin in a solvent using a second catalyst system in a second polymerization zone to provide a second polymer which is an elastorneric polymer comprising 30 wt % or more of units derived from ethylene that is either non-crystalline or has ethylene-derived crystallinity; combining the first polymer and the second polymer in a mixture that includes solvent and unreacted monomers; removing solvent and unreacted monomers from the mixture to form a single recycle stream, which is split into a first recycle stream and a second recycle stream; directing the first recycle stream to the first polymerization zone and directing the second recycle stream to the second polymerization zone to provide a recycle split; and recycling ethylene monomers, propylene monomers, and optionally alpha-olefin monomers and solvent for polymerization; to provide an elastomer composition having a Mooney Viscosity (ML (1+4) @125° C.) of from 16 to 180; wherein the process is operated in a series reactor mode or a parallel reactor mode and the percent recycle to the first reaction zone is equal to: a. 2.8 * (PS) 0.67 * (RT2/RT1) 1.11 in series reactor mode; or b. 4.5 * (PS) 0.55 * (RT2/RT1) 0.67 in parallel reactor mode, where PS=polysplit of polymer produced in the first polymerization zone to the total polymer produced in the first and second polymerization zones, RT2=second reaction zone temperature (° C.), and RT1=first reaction zone temperature (° C.).