VISCOSITY ADDITIVE FOR LUBRICATING OILS, PROCESS FOR ITS PREPARATION AND LUBRICATING COMPOSITIONS BASED ON THE SAID ADDITIVE

摘要

A composition of matter, particularly useful as a viscosity additive comprising: 6 to 15 parts by weight of a 60/40-54/46 ethylene/propylene copolymer of Mw 155,000-250,000 (OCP), 2 to 8 parts by weight of a poly(C1-C20 alkyl methacrylate) of Mw 30,000-150,000 (PMA) with a PMA/OCP ratio of 1/5 to 1/1, and the complement to 100 parts by weight of diluent oil. Also disclosed are lubricating compositions comprising the above additive composition, preferably in an amount of from 0.1 to 10% by weight based on the weight of lubricating oil.