Viscosity enhancing compositions that provide the lubricating oil with improved low temperature characteristics

摘要

A lubricating composition, comprising: an oil of lubricating viscosity; A) 0.05 to 1.5 percent by weight of a copolymer comprising 70 to 79 percent by weight of units derived from ethylene ("E"), having a Pm of 50,000 to 100,000, Pm / Mn less than 3, a density ("D") of 860 to 896 kg / m3 and a melting point ("Tf") of 15 ° C to 60 ° C, where E and Tf meet the expression 3.44E, 206 = Tf ; and (B) from 0.05 to 1.5 percent by weight of a block copolymer comprising a first block comprising an aromatic vinyl comonomer and a second block comprising a diene comonomer, the block containing hydrogenated diene monomer, where the content of vinyl aromatic monomer of the block copolymer (B) is 15 to 60 weight percent; where the weight ratio (A) :( B) is from 20:80 to 60:40, and where the block copolymer (B) comprises a portion of the blocks that is comprised of homopolymer segments or homopolymer segments of the monomer aromatic vinyl and another portion that is composed of homopolymer or homooligomer segments of the diene monomer.