Lubricant compositions

Claim 1

A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL, AND A SYNERGISTIC MIXTURE WITH REGARD TO INHIBITION OF SLUDGE FORMATION OF BETWEEN 0.0005 AND 6 WT. PERCENT OF AN ALKOXYLATED PHOSPHOSULFURIZED POLYBUTENE AND BETWEEN 0.04 AND 9.5 WT. PERCENT OF A POLYMER OF AN ALKOXYLATED PARTIAL ESTER OF AN ACID SELECTED FROM THE GROUP CONSISTING OF FUMARIC AND MALEIC ACID PARTIALLY ESTERIFIED WITH A C3 TO C20 MONOHYDRIC ALCOHOL, SAID PHOSPHOSULFURIZED POLYBUTENE BEING OBTAINED BY REACTING A SULFIDE OF PHOSPHORUS WITH POLYBUTENE HAVING A STAUDINGER MOLECULAR WEIGHT OF ABOUT 900 TO 1600 UNTIL 2 TO 12 WT. PERCENT SULFUR AND 1 TO 7 WT. PERCENT PHOSPHORUS IS INCORPORATED THEREIN, THEN REACTING SAID PHOSPHOSULFURIZED POLYBUTENE WITH A C2 TO C3 ALKYLENE OXIDE UNTIL AN AVERAGE OF 1 TO 10 ALKYLENE OXIDE RESIDUES ARE INCLUDED IN THE PHOSPHOSULFURIZED POLYBUTENE, AND WHEREIN SAID ALKOXYLATED PARTIAL ESTER IS PREPARED BY REACTING A C2 TO C3 ALKYLENE OXIDE WITH SAID PARTIAL ESTER UNTIL AN AVERAGE OF 1 TO 10 ALKYLENE OXIDE RESIDUES ARE INCORPORATED PER MOLE OF PARTIAL ESTER.