HYDRAULIC OIL FOR HIGH-DUTY HYDRAULIC SYSTEMS Russian patent published in 2003 - IPC

FIELD: special-destination fluids. SUBSTANCE: invention relates to hydraulic oils for use in hydraulic- drive and hydraulic-control systems of machines operated in the open air at temperatures in work volume of oil from -40 to +50 C depending on the type of hydraulic pump. Oil contains, wt.%: thickening additive 0.8-12.0; depressant 0.3-1.0; antioxidant 0.15-0.25, multifunctional additive 0.9-1.1; antifoaming additive, 0.002-0.004; and base oil, to 100%. The latter consists of fraction 270-420 with pour point no higher than -55 C obtained by vacuum distillation of fraction 270-420 C subjected to selective treatment with phenol or N- methylpyrrolidone and deparaffination. EFFECT: raised viscosity index and improved compatibility with rubber. 2 tbl, 12 ex