STAR-LIKE POLYMER MODIFYING VISCOSITY INDEX FOR OIL COMPOSITION AND VISCOSITY MODIFIER-CONTAINING OIL COMPOSITION Russian patent published in 2003 - IPC

FIELD: lubricants. SUBSTANCE: star-like polymers, which can be used as viscosity index modifiers in compositions of oils produced for high-performance engines. Star-like polymers have tetrablock- copolymer bifurcations containing hydrogenated polyisoprene-polybutadiene- polyisoprene blocks with polystyrene blocks, which give rise to excellent low- temperature operation characteristics in lube oils and are characterized by good efficiency with respect to solidification and can be isolated invention of polymer crumb. Structural formula of polymer has at least four monomer block, of which each is characterized by molecular weight distribution. Hydrogenated block copolymers have polyalkenyl coupling agent in their structure. EFFECT: extended assortment of high-molecular viscosity index modifiers. 8 cl, 3 tbl, 8 ex