Process for the preparation of thermoplastic elastomeric block copolymers

Claim 1

Process for preparing elastomeric block copolymers having the general configuration: A -- B -- (A).sub.n wherein A is a non-elastomeric polymer block with a number average molecular weight between 200 and 100,000, and a glass transition temperature above 25°C. formed from a monovinyl aromatic compound having from 8-20 carbon atoms per molecule; B is an elastomeric polymer block with a number average molecular weight between 20,000 and 1,000,000, and a glass transition temperature below 10°C. formed from a conjugated diene having from 4-12 carbon atoms in its molecule; and n is a whole or fractional number; comprising polymerizing, in the presence of a polyfunctional anionic initiator, a monomer to form elastomeric block B and thereafter continuing said polymerization also in the presence of said polyfunctional anionic initiator to polymerize a monomer of mixture of monomers to form polymer blocks A attached to polymer block B; said polyfunctional anionic initiator prepared by reacting (a) a monofunctional anionic initiator having the formula: R -- Li wherein R is an alkyl having 1 - 12 carbon atoms or allyl or allyl substituted with a lower alkyl having 1 - 4 carbon atoms; with (b) a monovinyl aromatic compound having from 8 - 12 carbon atoms per molecule the molar ratio of component (a) being from 1 to 5000 for each mole of component (b), and reacting the polymeric reaction product of (a) and (b) with: (c) a polyvinyl aromatic compound having up to 24 carbon atoms per molecule at a temperature between 10°C. and 150°C. in molar ratio of 0.25 to 10 moles per mole of component (a), and thereafter reacting the cross-linked polymeric reaction product of components (a), (b) and (c) with: (d) a monovinyl aromatic compound having 8 - 12 carbon atoms per molecule in a molar ratio of 0.5 - 100 moles per mole of component (a), to produce said polyfunctional anionic initiator.