Process for preparing a conjugated diene-vinyl-aromatic block copolymer with a lithium-condensed aromatic ring compound catalyst

Claim 1

A PROCESS FOR PREPARING A BLOCK COPOLYMER FORMED OF A CENTRAL COPOLYMER BLOCK AND TWO TERMINAL HOMOPOLYMER BLOCK WHICH PROCESS COMPRISES THE STEPS OF POLYMERIZING A MIXTURE OF (1) A CONJUGATED DIENE SELECTED FROM THE GROUP CONSISTING OF 1,3-BUTADIENE, ISOPRENE AND PIPERYLENNE, AND (2) A VINYL-SUBSTITUTED AROMATIC HYDROCARBON WITH AN INITIATOR COMPRISING THE REACTION PRODUCT OBTAINED BY WREACTING AT LEAST 2 GRAMS ATOMS OF LITHIUM PER MOLE OF A CONDENSED RING AROMATIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF NAPTHALENE AND PHENANTHRENE, AND ALKYL DERIVATIVES OF THESE COMPOUNDS IN AN ALIPHATIC MONOETHER HAVING THE FORMULA ROR, WHEREIN EACH R IS AN ALKYL GROUP CONTAINING 2 TO 12 CARBON ATOMS, INCLUSIVE, SAID POLYMERIZING OCCURRING IN THE PRESENCE OF A HYDROCARBON DILUENT SELECTED FROM THE GROUP CONSISTING OF PARAFINIC, CYCLOPARAFFINIC AND AROMATIC HYDROCARBONS AND THE AMOUNT OF SAID ETHER PRESENT IN THE POLYMERIZATION BEING LESS THAN ABOUT 1.75 PARTS OF ETHER PER 100 PARTS OF SAID MIXTURE OF A CONJUGATED DIENE AND A VINYL-SUBSTITUTED AROMATIC HYDROCARBON; AND RECOVERING THE BLOCK COPOLYMER PRODUCT SO PRODUCED.