Paraffinic shock absorber oils for vehicles - with improved low temp properties and lower volatility

摘要

Vibration damper oils, esp. for shock absorbers on vehicles, contg. as base oils, paraffinic fractions of boiling range 310-400 degrees C, which have been dewaxed, extracted and hydrofined, to give viscosity 21-25 c St. at 20 degrees C, pour point below -40 degrees and flash pt. over 140 degrees C, and other usual additives. The oils have improved cold performance, lower volatility and cost compared with usual naphthenic-based oils. Base oil content is pref. 80-99 (90-99) wt.% and additive content 20-1 (10-1) wt.%. To the base oil a spindle oil selective raffinate with viscosity 5.5-7.0 (around 6.3) c St. at 50 degrees C, density 0.840-0.880 (around 0.860) at 15 degrees C, flash pt. (Marcus) of 135-160 degrees (around 150 degrees C) and pour pt. -45 to -55 degrees (around -50 degrees)C, from a naphthene-based oil, may be added to give closer control of viscosity, the mixts. contg. 70-85 wt. % base oil, 25-14 % spindle oil and 5-1% additives.