Method for reducing foaming of lubricating oils

摘要

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 DEG C. to 93.5 DEG 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.