CONTINUOUS SOLUTION POLYMERIZATION PROCESS

1528039 Continuous anionic polymerization of conjugated dienes MICHELIN & CIE (COMPAGNIE GENERALE DES ESTABLISSEMENTS MICHELIN) 22 Dec 1975 [23 Dec 1974] 52416/75 Heading C3P Conjugated dienes are polymerized optionally with vinyl aromatic monomers, in continuous manner in an open reactor at 20‹ C. to 110‹ C. in solution in a hydrocarbon solvent and in the presence of a lithium or organolithium initiator, the polymerization being effected in the presence of a de-activating system consisting of (a) a chain transfer agent and/or a termination reagent and, when necessary, (b) a polar additive and/or metallation agent, the proportions of initiator, (a) and (b) being such that the ratio of the speed of the deactivation of the living macromolecules to the speed of propagation of the polymerization is from 10-5 to 5.10-3. The compounds employed may fulfil the function of more than one of the ingredients, e.g. toluene may act as chain transfer agent and solvent, vinyl toluene as a chain transfer agent and monomer, and hexamethyl phosphoramide as termination agent and polar additive. Typical Examples refer to the continuous polymerization of butadiene or butadiene/styrene using n- BuLi initiator and heptane or toluene as'solvents, the reagents (a) being toluene, hexamethyl phosphoramide, benzyl chloride or fluorene and where appropriate (b) tetrahydrofuran, sodium dihydrobis (2-methoxyethoxy)aluminate, sodium tetraethylaluminate, sodium naphthalene, and potassium benzophenone.