Conductive lubricating greases

Abstract

The present invention relates to the use of a sulfonate additive for increasing the electrical conductivity of a grease composition comprising at least one base oil and at least one thickener. The invention also relates to a grease composition comprising at least one base oil, at least one polyurea thickener and at least one sulfonate additive.

1 .- 14 . (canceled) 
     
     
         15 . A method for increasing the electrical conductivity of a grease composition comprising, said method comprising a step of mixing at least one sulfonate additive with at least one base oil and at least one thickener. 
     
     
         16 . The method according to  claim 15 , wherein the thickener is chosen from fatty acid metal salts and polyureas. 
     
     
         17 . The method according to  claim 15 , wherein the sulfonate additive is chosen from sulfonate metal salts. 
     
     
         18 . The method according to  claim 17 , wherein the metal salt of the sulfonate is selected from calcium salts, sodium salts, lithium salts, barium salts, magnesium salts, zinc salts. 
     
     
         19 . The method according to  claim 15 , wherein the sulfonate additive is chosen from sulfonates comprising at least one aromatic moiety optionally substituted by one or a plurality of aliphatic moieties. 
     
     
         20 . The method according to  claim 15 , wherein the sulfonate additive is chosen from sulfonates comprising at least one naphthalene moiety optionally substituted by one or a plurality of aliphatic moieties. 
     
     
         21 . The method according to  claim 15 , wherein the sulfonate additive is chosen from alkylnaphthalene sulfonate, dialkylnaphthalene sulfonate, alkylnaphthalene sulfonate/carboxylate and dialkylnaphthalene sulfonate/carboxylate. 
     
     
         22 . The method according to  claim 15 , wherein the sulfonate additive is added in a concentration ranging from 0.1 to 10% by weight, relative to the total weight of the grease composition after addition of the sulfonate additive. 
     
     
         23 . A grease composition comprising, with respect to the total weight of the grease composition:
 from 70 to 95% by weight of base of oil(s),   from 4 to 20% by weight of thickener(s) chosen from polyureas,   0.1 to 10% by weight of sulfonate additive(s).   
     
     
         24 . The grease composition according to  claim 23 , wherein the sulfonate additive comprises one or more of the following features:
 the sulfonate additive is chosen from sulfonate metal salts,   the sulfonate additive is chosen from sulfonates comprising at least one aromatic moiety optionally substituted by one or a plurality of aliphatic moieties or from sulfonates comprising at least one naphthalene moiety optionally substituted by one or a plurality of aliphatic moieties,   the sulfonate additive is chosen from alkylnaphthalene sulfonate, dialkylnaphthalene sulfonate, alkylnaphthalene sulfonate/carboxylate and dialkylnaphthalene sulfonate/carboxylate.   
     
     
         25 . The grease composition according to  claim 23 , having a resistivity at 100° C. of less than or equal to 1.0×10 8  ohm·meters. 
     
     
         26 . The grease composition according to  claim 23 , comprising:
 from 75 to 90% by weight of base oil(s)   from 5 to 15% by weight of thickener chosen from polyureas,   from 0.5 to 5% by weight of sulfonate additive chosen from metal sulfonate salts comprising at least one naphthalene group substituted by one or more aliphatic groups, the salts being chosen from calcium salts, sodium salts and lithium salts, barium salts and magnesium salts.   
     
     
         27 . The grease composition according to  claim 23 , said composition comprising, relative to the total weight of the grease composition, less than 1% by weight of calcium 12-hydroxystearate and less than 1% by weight of calcium stearate. 
     
     
         28 . The grease composition according to  claim 23 , characterized in that the grease composition is free of calcium 12-hydroxystearate and free of calcium stearate. 
     
     
         29 . The method according to  claim 15 , wherein the thickener is chosen from polyureas. 
     
     
         30 . The method according to  claim 15 , wherein the thickener is chosen from diureas. 
     
     
         31 . The method according to  claim 15 , wherein the sulfonate additive is chosen from sulfonates comprising at least one naphthalene moiety substituted by one or a plurality of aliphatic moieties. 
     
     
         32 . The method according to  claim 15 , wherein the sulfonate additive is added in a concentration ranging from 0.5 to 5% by weight, relative to the total weight of the grease composition after addition of the sulfonate additive. 
     
     
         33 . The grease composition according to  claim 23 , said composition comprising, relative to the total weight of the grease composition, less than 0.1% by weight of calcium 12-hydroxystearate and less than 0.1% by weight of calcium stearate. 
     
     
         34 . A method for increasing the electrical conductivity of a grease composition comprising at least one base oil and at least one thickener, said method comprising a step of using at least one sulfonate additive.