Grease compositions

Abstract

The invention relates to a grease composition having a base oil and a thickener that includes hydrophilic metal oxide particles and one or more esters which contain one or more unsaturated C—C bonds and/or at least one OH group. The hydrophilic metal oxide particles have a BET specific surface area of at least 10 m 2 /g and at least 80% of the hydrophilic metal oxide particles have a particle size in the range of from 5 nm to 900 μm. The amount of the thickener is in the range of from 0.1-40% by weight, based on the total weight of the grease composition. The invention further relates to methods for manufacturing the grease compositions, and the use of the grease compositions for lubricating bearings, gears and couplings.

1 . A grease composition comprising:
 a base oil, and   a thickener that provides hydrophilic metal oxide particles and one or more esters which contain one or more unsaturated C—C bonds and/or at least one OH group, wherein   the hydrophilic metal oxide particles have a BET specific surface area of at least 10 m 2 /g and at least 80% of the hydrophilic metal oxide particles have a particle size in the range of from 5 nm to 900 μm, and wherein   the amount of the thickener is in the range of from 0.1-40% by weight, based on the total weight of the grease composition.   
     
     
         2 . The grease composition according to  claim 1 , wherein the one or more esters contain one or more unsaturated C—C bonds and at least one OH group. 
     
     
         3 . The composition according to  claim 1 , wherein the one or more esters contain two or more unsaturated C—C bonds. 
     
     
         4 . The grease composition according to  claim 1 , wherein the one or more esters are diesters. 
     
     
         5 . The grease composition according to  claim 1 , wherein the one or more esters are metal salts. 
     
     
         6 . The grease composition according to  claim 1 , wherein the one or more esters are esterified fatty acids. 
     
     
         7 . The grease composition according to  claim 1 , wherein the thickener further comprises one or more metal salts of fatty acids, one or more fatty acids, one or more amides, and/or one or more amines. 
     
     
         8 . The grease composition according to  claim 7 , wherein the thickener further comprises one or more metal salts of fatty acids. 
     
     
         9 . The grease composition according to  claim 7 , wherein the additional one or more metal salts of fatty acids, one or more fatty acids, one or more amides and/or one or more amines contain one or more unsaturated C—C bonds and/or at least one OH group. 
     
     
         10 . The grease composition according to  claim 1 , further comprising one or more sulphonates, sulphates, phosphates and/or phosphonates. 
     
     
         11 . The composition according to  claim 1 , wherein the metal oxide is silicon oxide. 
     
     
         12 . The composition according to  claim 11 , wherein the silicon oxide is amorphous fumed silicon oxide. 
     
     
         13 . The composition according to  claim 5 , wherein the one or more metal salts are calcium salts. 
     
     
         14 . A method for manufacturing a grease composition having a base oil, and a thickener that provides hydrophilic metal oxide particles and one or more esters which contain one or more unsaturated C—C bonds and/or at least one OH group, wherein the hydrophilic metal oxide particles have a BET specific surface area of at least 10 m 2 /g and at least 80% of the hydrophilic metal oxide particles have a particle size in the range of from 5 nm to 900 μm, and wherein the amount of the thickener is in the range of from 0.1-40% by weight, based on the total weight of the grease composition, the method comprises:
 mixing the base oil, the hydrophilic metal oxide particles and the one or more esters that contain one or more unsaturated C—C bonds and /or at least one OH group in any possible order of sequence and 
 subjecting before or after mixing the hydroxyl group containing metal compound, the one or more esters that contain one or more unsaturated C—C bonds and /or at least one OH group to a mechanical treatment, a thermal treatment or to both a mechanical treatment and a thermal treatment. 
 
     
     
         15 . A grease composition having a base oil, and a thickener that provides hydrophilic metal oxide particles and one or more esters which contain one or more unsaturated C—C bonds and/or at least one OH group, wherein the hydrophilic metal oxide particles have a BET specific surface area of at least 10 m 2 /g and at least 80% of the hydrophilic metal oxide particles have a particle size in the range of from 5 nm to 900 μm, and wherein the amount of the thickener is in the range of from 0.1-40% by weight, based on the total weight of the grease composition used for lubricating a bearing, a gearing or a coupling.