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AssigneeExxon Research & Engineering Co.
InventorsLilianna Zofia Pillon, Patrick Desmond Fraser Vernon, Andre Ernest Asselin
Estimating the term…
Foaming of a lube oil comprising a base stock derived from wax isomeration and an additive package is effectively reduced to within specification limits of 50 ml/ml over a temperature range of from at least 24.degree. C. to 93.5.degree. C. by adding to the oil an effective amount of an antifoamant exhibiting a spreading coefficient of at least about 2 mN/m. This has been found to be particularly effective in reducing foaming of lube oils containing a mixture of a wax isomerate oil and a petroleum oil fraction. Antifoamants typically used with conventional lube oils containing one or more petroleum fraction base stocks, but which do not exhibit a spreading coefficient of at least 2 mN/m with the wax isomerate containing oil, have been found not to be effective in reducing the foaming of the oil.
A method for reducing foaming at both 24.degree. C. and 93.5.degree. C. of a lube oil which comprises a wax isomerate base stock, said method comprising adding to the oil an antifoamant or solvent solution thereof, consisting of a polydimethyl siloxane oil having a viscosity at 25.degree. C. of 60,000 to 100,000 cSt and which exhibits a spreading coefficient of at least about 2 mN/m at both 24.degree. C. and 93.5.degree. C. with said lube oil, said antifoamant being added in an amount effective to reduce said foaming, said effective amount being about 1 to 10 ppm active ingredient based on the total lube oil.
A lube oil comprising an effective amount of a wax isomerate base stock oil of lubricating quality and at least one additive and an antifoamant or solvent solution thereof, said antifoamant consisting of a polydimethyl siloxane oil having a viscosity at 25.degree. C. of 60,000 to 100,000 cSt and which exhibits a spreading coefficient of at least about 2 mN/m at both 24.degree. C. and 93.5.degree. C. with said lube oil, said antifoamant present in an amount effective in reducing the foaming of the lube oil at both 24.degree. C. and 93.5.degree. C. to a point below that which it would be if said antifoamant was not present, said effective amount being between about 1 to 10 ppm active ingredient based on the total lube oil.
Dependencies are inferred from the claim text.