HYDRAULIC FLUID FOR AUTOMATIC TRANSMISSION Russian patent published in 2013 - IPC C10M169/04 C10M101/02 C10N40/08 

FIELD: chemistry.

SUBSTANCE: invention relates to compositions of hydraulic fluids used in automatic transmission. Improvements are achieved by adding isomerised slack wax (fraction 360°C - K.K) to an oil base which is a low-viscosity distillate component. The low-viscosity distillate component is obtained from vacuum distillate of a crude oil distillation plant (fraction 300-450°C) through selective purification, dewaxing and hydrofining. The isomerised slack wax (fraction 360°C - K.K) is obtained by a catalytic method from petroleum slack wax - a by-product of plants for dewaxing refined oil (fraction 300°C - K.K) with oil content of 2.5-12 wt % by hydrofining, hydroisodewaxing, hydrogenation with subsequent fractionation. The isomerised slack wax has kinematic viscosity at 100°C in the range of 3.9-4.7 mm²/s, chilling point not higher than minus 10°C and open flash point not lower than 210°C. Components of the hydraulic fluid for automatic transmission are in the following ratio, wt %: multifunctional additive (antiwear, antioxidant, friction modifier, viscosity modifier) 14-18; anticorrosion additive 0.06-0.1; antifoam agent 0.002-0.006, dye 0.002-0.003, base - up to 100, wherein the base contains, wt %: a low-viscosity distillate component - 20-70; isomerised slack wax - 30-80.

EFFECT: improved viscosity-temperature characteristics: low dynamic viscosity at minus 40°C, higher viscosity index, low chilling point, reduced susceptibility to foaming.

1 cl, 4 tbl, 1 ex