Process and catalyst for production of polybutadiene

Claim 1

A PROCESS WHICH COMPRISES POLYMERIZING BUTADIENE TO FORM A RUBBERY POLYMER CONTAINING AT LEAST 85 PERCENT CIS-1,4 ADDITION, IN THE PRESENCE OF A CATALYST WHICH FORMS ON MIXING A COMPOUND HAVING THE FORMULA RLIX, A COMPOUND HAVING THE FORMULA RNALIM, AND A COMPOUND HAVING THE FORMULA TIX4, WHEREIN R IS A HYDROCARBON RADICAL SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC, CYCLOALIPHATIC AND AROMATIC RADICALS HAVING FROM 1 TO 20 CARBON ATOMS, X IS AN INTEGER IN THE RANGE 1 TO 4, M AND N ARE INTEGERS EACH OF WHICH IS AT LEAST 1 AND THE SUM OF WHICH IS 3, AND X IS A HALOGEN SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE, AND IODINE, WHEREIN SAID POLYMERIZING IS CARRIED OUT IN AT LEAST A TWO STEP POLYMERIZATION PROCESS WITH THE POLYMERIZATION TEMPERATURE IN THE SECOND POLYMERIZATION STEP BEING AT LEAST 20*F. HIGHER THAN THE POLYMERIZATION TEMPERATURE IN THE FIRST POLYMERIZATION STEP AND THE CONVERSION OF MONOMER INTO POLYMER BEING AT LEAST 40 PERCENT IN SAID FIRST POLYMERIZATION STEP, SAID POLYMER HAVING A STEREO CONFIGURATION APPROXIMATELY THE SAME AS AND LESS TENDENCY TO COLD FLOW THAN A POLYMER MADE WITHOUT THE TWO STEP POLYMERIZATION TEMPERATURE PROCESS.