Grease composition and methods for manufacturing the grease composition
AssigneeAktoebolaget Skf
InventorsSébastien David, Franciscus Catherina Martinus Fiddelaers
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Abstract
The present invention relates to a non-hydroxide grease composition comprising a base oil and a thickener which comprises amorphous hydrophilic silicon oxide particles and one or more metal salts of different organic acids, wherein the silicon oxide particles have a BET specific surface area of at least 50 m2/g and wherein the amount of the metal salt(s) is 4-25% by weight, based on the total weight of the grease composition. The present invention further relates to a method for manufacturing said grease composition and the use of said grease composition for lubricating a bearing and in couplings and gearings.
Claims12
A non-hydroxide grease composition comprising:
- a base oil,
- 1-5% by weight, based on the total weight of the grease composition, amorphous hydrophilic silicon oxide particles, and
- one or more metal salts of different organic acids in a non-saponified state, the metal salt(s) being selected from the group consisting of calcium stearate and calcium 12-hydroxystearate, wherein:
- the silicon oxide particles have a BET specific surface area of at least 50 m2/g and at least 80% of the silicon oxide particles have a mean particle size of 5-50 nm,
- the amount of the metal salt(s) is 4-20% by weight, based on the total weight of the grease composition, with the proviso that the total amount of the amorphous hydrophilic fumed silicon oxide particles and the one or more metal salts of different organic acids is 8-25% by weight, based on the total weight of the grease composition,
- the base oil is mineral oil and/or poly-α-olefin,
- the base oil is present in the grease composition in an amount of 70-90 wt % by weight based upon the total weight of the grease composition, and
- the grease composition has a dropping point higher than 220° C. and contains less than 0.2 wt % of free hydroxide ions and/or metal hydroxide.
A grease prepared by mixing, in weight percent based upon the total weight of the grease:
- 70-90 wt % mineral oil and/or poly-α-olefin,
- 1-5 wt % amorphous hydrophilic fumed silicon oxide particles having a BET specific surface area of at least 50 m2/g and, at least 80% of the silicon oxide particles having a mean particle size of 5-50 nm, and
- 5-20 wt % at least substantially pure calcium stearate and/or calcium 12-hydroxystearate, with the proviso that the total amount of the amorphous hydrophilic fumed silicon oxide particles and the calcium stearate and/or calcium 12-hydroxystearate is 8-20 wt %,
- wherein the grease composition has a dropping point higher than 220° C. and contains less than 0.2 wt % of free hydroxide ions and/or metal hydroxide.
Dependencies are inferred from the claim text.