Lubricant containing dispersant-pour depressant polymer

Claim 1

A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL, A VISCOSITY INDEX IMPROVING OIL SOLUBLE COPOLYMER COMPRISING ESSENTIALLY ETHYLENE AND PROPYLENE, HAVING A VISCOSITY AVERAGE MOLECULAR WEIGHT IN THE RANGE OF ABOUT 10,000 TO 200,000 AND CONTAINING ABOUT 60 TO 80 MOLE PERCENT ETHYLENE, AND A MINOR AMOUNT OF A POUR DEPRESSING AND DISPERSING OIL SOLUBLE ACRYLATE COPOLYMER, COMPATIBLE WITH SAID ETHYLENEPROPYLENE COPOLYMER OF (A) A MIXTURE CONSISTING ESSENTIALLY OF AT LEAST ONE C8 OR C10 ALKYL ESTER AND AT LEAST ONE C14 ORCUL ALKYL ESTER, SAID ESTERS BEING EATERS OF AN ACRYLIC AID SELECTED FROM THE GROUP CONSISIIN OF UNSUBSTITUTED ACRYLIC ACID AND METHACRYLIC ACID, WHEREIN ALL OF THE ALKYL ESTERS HAVE THE SAME ACID MOIETY AND SAID ALKYL GROUPS ARE STRAIGHT CHAIN, AND (B) A NITRIGEN-CONTAINING ETHYLENICALLY UNSATURATED MONOMER SELECTED FROM THE GROUP CONSISTING OF N,N-DIMETHYL AMINOETHY METHACRYLATE AND 4-VINYL PYRIDINE, SAID ACRYLATE COPOLYMER HAVING A NUMBER AVERAGE MOLECULAR WEIGHT IN THE RANGE OF ABOUT 2,000 TO ABOUT 20,000, AND A NITROGEN CONTENT OF ABOUT 0.2 PERCENT TO ABOUT 5 PERCENT BY WEIGHT SAID ACRYLATE COPOLYMER BEING PRODUCED FROM A MONOMER MIXTURE WHICH INITALLY IS ESSENTIALLY FREE OF POLYMER, AND WHEREIN SAID ACRYLATE COPOLYMER IS THE SOLE ACRYLATE COPOLYMER PRESENT IN SAID COMPOSITION.