Lubricant base stock
AssigneeEquus UK Topco Ltd
InventorsKevin John Duncan, Paul Bonner
Life of this patent
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Abstract
The present invention relates to a lubricant base stock, lubricant formulations, a method of lubricating a rotating shaft within a stern tube and the use of a lubricant base stock. The base stock and lubricant formulations may be particularly suited for use in aqueous environments (including fresh water or salt water). A lubricant base stock comprising a first (EO)(PO)(EO) block co-polymer and a second (EO)(PO)(EO) block co-polymer which is different from the first (EO)(PO)(EO) block co-polymer in a marine lubricant formulation wherein the lubricant base stock has a density of at least 1028 kg/m3 at 20° C. and at most 1022 kg/m3 at 40° C. in particular is provided.
Claims14
A lubricant base stock comprising:
- a) at least 10 wt % of a first polyalkylene glycol block co-polymer having an (EO)(PO)(EO) block structure and having a kinematic viscosity at 40° C. of at most 150 mm2/s (cSt);
- and
- b) at least 10 wt % of a second polyalkylene glycol block co-polymer having an (EO)(PO)(EO) block structure and having a kinematic viscosity at 40° C. different to that of the first polyalkylene glycol block co-polymer;
- wherein the total wt % of polyalkylene glycol block co-polymers in the lubricant base stock is at least 87 wt %;
- wherein the lubricant base stock comprises less than 8 wt % water;
- wherein the lubricant base stock has a kinematic viscosity at 40° C. from 70 mm2/s (cSt) to 250 mm2/s;
- and
- wherein the lubricant base stock is insoluble when added at 1 wt % to seawater at a temperature of at least 40° C.
A method of lubricating a rotating shaft within a stern tube on a marine vessel comprising the step of contacting the rotating shaft with a lubricant formulation comprising:
- a) a first (EO)(PO)(EO) block co-polymer;
- and
- b) a second (EO)(PO)(EO) block co-polymer which is different from the first (EO)(PO)(EO) block co-polymer;
- wherein the lubricant formulation has a density of at least 1028 kg/m3 at 20° C. and at most 1022 kg/m3 at 40° C., and
- wherein the lubricant formulation is insoluble when added at 1 wt % to seawater at a temperature of at least 40° C.
A marine lubricant formulation comprising a lubricant base stock comprising a first (EO)(PO)(EO) block co-polymer and a second (EO)(PO)(EO) block co-polymer which is different from the first (EO)(PO)(EO) block co-polymer, wherein the lubricant base stock has a density of at least 1028 kg/m3 at 20° C. and at most 1022 kg/m3 at 40° C., and wherein the lubricant base stock is insoluble when added at 1 wt % to seawater at a temperature of at least 40° C.
Dependencies are inferred from the claim text.