Patent ID: 8193135

Claim:
A process for the preparation of a viscosity index improver (V.I.I.) of lubricating oil which comprises a mixing treatment under high shear conditions of a composition comprising: (i) one or more EPM polymers; one or more EPDM polymers; or a mixture of one or more EPM polymers and one or more EPDM polymers; (ii) one or more polyvinylarene/conjugated hydrogenated polydiene/polyvinylarene block copolymers consisting of a styrene/ethylene-butene/styrene (SEBS) copolymer; and (iii) lubricating oil, in which (ii) is present in a concentration of 1.5 to 20% by weight and (iii) is present in a concentration ranging from 1.5 to 45% by weight.