METHOD FOR PREPARING MODIFIED CIS-1,4-POLYISOPRENE Russian patent published in 2003 - IPC

FIELD: organic chemistry, polymers, chemical technology. SUBSTANCE: invention relates to modification of cis-1,4-polyisoprene and can be used in plants of chemical industry for preparing СКИ-3 with the improved properties and the prepared polymer can be used in manufacture of tires and rubber technical articles. Modified cis-1,4-polyisoprene is prepared by polymerization of isoprene in hydrocarbon solvent in the presence of Ziegler-Nutt's catalyst, the following deactivation of catalyst by addition of alkaline salt solution as a modifying agent, stabilization of polymer, washing out from residues of catalytic complex, isolation of polymer by drying. Before deactivation of catalyst an acid solution is added to polymerization product in the mole ratio modifying agent : acid = 1.0 : (1.0-2.5) where ortho-phosphoric acid or hydroxyethylidene diphosphonic acid is used as acid and p-nitro- sodiphenylamine or N-4-diphenylaminomaleinamide is used as a modifying agent. Method ensures to reduce loss of reagent a modifying agent in washing out a polymer with water at any pH value and to distribute its more uniformly, reduce toxicity of process and improve ecology in working zone of works of polymerization, isolation and in БОС units, reduce content of titanium ions in rubber. EFFECT: improved preparing method. 2 tbl