Ultra Low Phosphorus Lubricant Compositions

Abstract

A low-phosphorus lubricating composition has less than 600 ppm phosphorus, comprising at least 85 weight % of a lubricating base blend, and an additive comprising the following, as weight % of the total composition: (1) an organomolybdenum compound at an amount which provides about 0.1-800 ppm Mo; (2) a hindered phenol at about 0.1-2%; and (3) a dithiocarbamate at about 0.1-2%; with a first proviso that where the dithiocarbamate does not comprise a metal dithiocarbamate, the additive additionally comprises: (4) an alkylated diphenylamine at about 0.1-2%, and with a second proviso that where the organomolybdenum compound comprises molybdenum dithiocarbamate, it is considered a metal dithiocarbamate for purposes of the first proviso [G1] , but is considered an organomolybdenum compound for the purposes of calculation of the amount present in the total composition.

1 . A low-phosphorus lubricating composition having less than 600 ppm phosphorus, comprising at least 85 weight % of a lubricating base blend, and an additive comprising the following, as weight % of the total composition:
 (1) an organomolybdenum compound at an amount which provides about 0.1-800 ppm Mo;   (2) a hindered phenol at about 0.1-2%; and   (3) a dithiocarbamate at about 0.1-2%;   with a first proviso that where the dithiocarbamate does not comprise a metal dithiocarbamate, the additive additionally comprises:   (4) an alkylated diphenylamine at about 0.1-2%,   and with a second proviso that where the organomolybdenum compound comprises molybdenum dithiocarbamate, it is considered a metal dithiocarbamate for purposes of the first proviso, but is considered an organomolybdenum compound for the purposes of calculation of the amount present in the total composition.   
     
     
         2 . The composition of  claim 1 , wherein the dithiocarbamate comprises a zinc dithiocarbamate. 
     
     
         3 . The composition of  claim 1 , wherein the dithiocarbamate is an ashless dithiocarbamate. 
     
     
         4 . The composition of  claim 3 , wherein the ashless dithiocarbamate is methylene-bis-dialkyldithiocarbamate. 
     
     
         5 . The composition of  claim 1 , wherein the organomolybdenum compound is one or both in combination of
 (a) a complex prepared by reacting about 1 mole of fatty oil, about 1.0 to 2.5 moles of diethanolamine and a molybdenum source sufficient to yield about 0.1 to 12.0 percent of molybdenum; and   (b) molybdenum dithiocarbamate.   
     
     
         6 . The composition of  claim 1 , wherein the hindered phenol is 2′6′-di tert butyl phenol, optionally para-substituted with —CH2—CH2—C(O)—OR1, where R1 is chosen from the group consisting of butyl, ethylhexyl, iso-octyl, isostearyl and stearyl. 
     
     
         7 . The composition of  claim 1 , wherein the hindered phenol is (iso-octyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate). 
     
     
         8 . The composition of  claim 3 , further comprising a corrosion inhibitor. 
     
     
         9 . The composition of  claim 1 , wherein the lubricating composition exhibits phosphorus retention of at least 79% when used in an engine. 
     
     
         10 . The composition of  claim 1 , wherein the dithiocarbamate is a zinc dithiocarbamate, and the composition is substantially free of alkylated diphenylamine. 
     
     
         11 . The composition of  claim 1 , wherein
 (1) the organomolybdenum compound is present an amount which provides about 50-800 ppm Mo;   (2) the hindered phenol is present at about 0.5-1.5%; and   (3) the dithiocarbamate is present at about 0.25-1.5%;   (4) the alkylated diphenylamine, if present, is at about 0.25-1.25%.   
     
     
         12 . The composition of  claim 11 , wherein
 (1) the organomolybdenum compound is present an amount which provides about 700 ppm Mo;   (2) the hindered phenol is present at about 0.5-1.5%; and   (3) the dithiocarbamate is present at about 0.4-1.0%;   (4) the alkylated diphenylamine, if present, is at about 0.25-1.25%.   
     
     
         13 . The composition of  claim 1 , wherein
 (1) the organomolybdenum compound is present an amount which provides about 50-800 ppm Mo;   (2) the hindered phenol is present at about 0.5-1.5%; and   (3) the dithiocarbamate comprises a zinc dithiocarbamate present at about 0.25-1.5%;   and the composition is substantially free of alkylated diphenylamine.   
     
     
         14 . The composition of  claim 13 , wherein
 (1) the organomolybdenum compound is present an amount which provides about 700 ppm Mo;   (2) the hindered phenol is present at about 0.75-1.5%; and   (3) the zinc dithiocarbamate is present at about 0.5%.   
     
     
         15 . A method of lubricating an engine to provide improved phosphorus retention and/or improved inhibition of lead and/or copper corrosion, and/or improved fuel economy and/or high temperature deposit control and/or exhaust system catalyst compatibility, in conjunction with a low-phosphorus lubricating composition, comprising using the lubricating composition of  claim 1  in an engine. 
     
     
         16 . The method of  claim 15 , wherein the use of the lubricating composition results in improved phosphorus retention and improved inhibition of lead and/or copper corrosion.