Lubricating fluids with low traction characteristics
AssigneeExxonMobil Chemical Patents Inc.
InventorsWilliam T. Sullivan, Halou Oumar-Mahamat, Martin N. Webster, Ellen B. Brandes
Life of this patent
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Abstract
The invention relates to lubricating fluids and oil formulations which provide exceptionally low traction, a method of lowering traction coefficients in lubricating compositions, and to uses of such compositions.
Claims27
A method of reducing the traction coefficient of a lubricant composition comprising a basestock selected from API Group I fluids, API Group II fluids, API Group III fluids, esters, polyalkylene glycol, alkylated naphthalene, or poly alpha-olefins oligomerized from linear C5 to C14 alpha-olefins, the basestock having a viscosity of at least 100 cSt at 100° C. (ASTM D-445), said method comprising blending a traction reducer in an amount in the range of 30 to 70 wt % based on the combined weight of said basestock wherein the traction coefficient of said lubricant composition is less than the traction coefficient of said basestock for every percent slide-roll ratio greater than or equal to 5, measured over the operating range of 0.1 to 3.5 GPa peak contact pressure, at −40° C. to 200° C. lubricant temperature, with a lubricant entraining velocity of from 0.25 to 10.0 m/s, said traction reducer further characterized by being miscible with said basestock, selected from API Group V or a non API category hydrocarbon fluid and having a viscosity of less than or equal to 3 cSt at 100° C. (ASTM D-445).
A lubricating composition comprising:
- (a) at least one basestock, said basestock characterized by having a viscosity of at least 100 cSt at 100° C. (ASTM D-445), and selected from API Group I fluids, API Group II fluids, API Group III fluids, esters, polyalkylene glycol, alkylated naphthalene, or poly alpha-olefins oligomerized from linear C5 to C14 alpha-olefins;
- (b) at least one traction reducer, said traction reducer characterized by being miscible with said basestock and having a viscosity of less than or equal to 3 cSt at 100° C. (ASTM D-445) and having a traction coefficient less than the traction coefficient of the base stock described in (a);
- wherein the at least one traction reducer (b) is present in the amount of 30 to 70 wt. %, based on the weight of said lubricating composition;
- and
- wherein said lubricating composition is characterized by a traction coefficient less than the traction coefficient of the at least one basestock for every percent slide-to-roll ratio greater than 5%, measured over the operating range of 0.1 to 3.5 GPa peak contact pressure, −40° C. to 200° C. lubricant temperature, with a lubricant entraining velocity of from 0.25 to 10.0 m/s;
- said composition further characterized by one of the following:
- (i) wherein (a) is selected from esters, PAGs, and alkylated naphthalenes;
- or
- (ii) wherein (b) is selected from monobasic acid esters and (a) is not a PAO.
In an apparatus comprising roller or spherical bearings, hypoid axles or gears or worm gears in contact with a lubricating fluid, the improvement comprising a lubricating fluid characterized by:
- (a) at least one basestock selected from API Group I fluids, API Group II fluids, API Group III fluids, esters, polyalkylene glycol, alkylated naphthalene, or poly alpha-olefins oligomerized from linear C5 to C14 alpha-olefins, said basestock characterized by having a viscosity of at least 100 cSt at 100° C. (ASTM D-445);
- (b) at least one traction reducer, said traction reducer characterized by being miscible with said basestock, selected from API Group V fluids or a non API category hydrocarbon fluid, and having a viscosity of less than or equal to 3 cSt at 100° C. (ASTM D-445) and having a traction coefficient less than the traction coefficient of the base stock described in (a);
- wherein the at least one traction reducer (b) is present in the amount of 30 to 70 wt. %, based on the weight of said lubricating composition;
- and
- wherein said lubricating composition is further characterized by a traction coefficient less than the traction coefficient of said at least one basestock (a) for every percent slide-to-roll ratio greater than 5%, measured over the operating range of 0.1 to 3.5 GPa peak contact pressure, −40° C. to 200° C. lubricant temperature, with a lubricant entraining velocity of from 0.25 to 10.0 m/s.
Dependencies are inferred from the claim text.