GREASE COMPOSITIONS

Abstract

The invention relates to a grease composition including a base oil and a thickener that provides hydrophilic metal oxide particles and one or more amides 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 m2/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 composition, and the use of the grease composition for lubricating bearings, gears and couplings.

Claims

1. A grease composition comprising: a base oil and a thickener that includes hydrophilic metal oxide particles and one or more amides that 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.sup.2/g, wherein 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 amides contain one or more unsaturated C—C bonds and at least one OH group.

3. The grease composition according to claim 1, wherein the one or amides contain one or more saturated C—C bonds.

4. The grease composition according to claim 1, wherein the one or more amides contain at least one OH group.

5. The grease composition according to claim 1, wherein the one or more amides contain one or more unsaturated C—C bonds and at least two OH groups.

6. The grease composition according to claim 1, wherein the one or amides contain two or more unsaturated C—C bonds.

7. The grease composition according to claim 1, wherein the one or more amides are fatty acid amides.

8. The grease composition according to claim 1, wherein the one or more amides are metal salts.

9. The grease composition according to claim 1, comprising in addition one or more metal salts of fatty acids.

10. The grease composition according to claim 1, comprising in addition one or more metal sulphonates, metal sulphates, metal phosphates and/or metal phosphonates.

11. The grease composition according to claim 1, wherein the metal oxide is silicon oxide.

12. The grease composition according to claim 11, wherein the silicon oxide is amorphous fumed silicon oxide.

13. A method for manufacturing a grease composition, the grease composition having a base oil and a thickener that includes hydrophilic metal oxide particles and one or more amides that 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.sup.2/g, wherein 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 amides 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 hydrophilic metal oxide particles, the one or more amides 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.

14. A grease composition for lubricating a bearing, a gearing or a coupling having a base oil and a thickener that includes hydrophilic metal oxide particles and one or more amides that 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.sup.2/g, wherein 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.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0102] In FIG. 1, the results of the four grease compositions are compared with each other, whereby the values of the Stribeck friction coefficient and the entrainment speed [mms-1] measurements obtained on the MTM rig are shown. The boundary, mixed and full film lubricating regimes are indicated in the figure over the ranges of entrainment speeds.

DETAILED DESCRIPTION OF THE INVENTION

[0103] From FIG. 1 it will be clear that the grease composition according to the present inventions constitutes a considerable improvement over the comparative examples wherein use is made of grease compositions that conventional thickeners. In this respect it is observed in accordance with the present invention the Stribeck friction coefficient is much lower in all three lubricating regimes when compared with the conventional grease compositions.