Production of bimodal cispolybutadiene

Claim 1

A CONTINUOUS TWO-STAGE POLYMERIZATION PROCESS FOR THE PRODUCTION OF POLYBUTADIENE CONTAINING AT LEAST 85 PERCENT CIS-1,4,-ADDITION IN THE PRESENCE OF AN INITIATOR OBTAINED BY MIXING AT LEAST ONE ORGANOMETAL COMPOUND AS A FIRST COMPONENT AND A SECOND IODIEN CONTAINING COMPONENT CONTAINING A TITANIUM HALIDE, COMPRISING CONTINUOUSLY INTRODUCING 1,3-BUTADIENE, A HYDROCARBON DILUENT, AND INITIATOR TO A FIRST POLYMERIZATION ZONE, THE AMOUNT OF TITANIUM CHARGED TO SAID FIRST ZONE BEING IN THE RANGE OF 0.02 TO 0.15 GRAM MILLIMOLS PER 100 GRAMS OF BUTADIENE, POLYMERIZING 50 TO 80 PERCENT OF THE BUTADIENE CHARGED IN SAID FIRST POLYMERIZATION ZONE, CONTINUOUSLY WITHDRAWING A FIRST POLYMERIZATION EFFLUENT FROM SAID FIRST POLYMERIZATION ZONE, CONTINUOUSLY ADDING ADDITIONAL BUTADIENE, TOLUENE, AND INITIATOR TO SAID FIRST EFFLUENT, CONTINUOUSLY INTRODUCING THE RESULTING MIXTURE INTO A SECOND POLYMERIZATION ZONE, THE AMOUNT AF ADDITIONAL INITIATOR BEING SUFFICIENT TO PROVIDE AN AMOUNT OF TITANIUM IN SAID SECOND POLYMERIZATION ZONE OF 0.2 TO 2 GRAM MILLIMOLS PER 100 GRAMS OF BUTADIENE CHARGED THERETO INCLUDING THAT CHARGED TO SAID FIRST ZONE, AND CONTINUING POLYMERIZATION TO AN OVERALL CONVERSION OF 60 TO 90 PERCENT, THE AMOUNT OF BUTADIENE BEING FED TO EACH OF SAID ZONES BEING ADJUSTED SO THAT THE FINAL POLYMER PRODUCT CONTAINS 2 TO 45 PERCENT BY WEIGHT OF MATERIAL PRODUCED IN SAID FIRST ZONE.