Table 1: Biodegrable fluids Mineral Oil Glycols Vegetable oils Synthetic Esters Density at 20C (Kg/M3) 880 1100 940 930 Viscosity index 100 100 to 200 100 to 200 120 to 220 Shear stability Good Good Good Good Pour point (C) -15 -40 to +20 -20 to +10 -60 to 20 Cold flow properties Good Very good Poor Very good Miscibility with mineral oil Not Miscible Good Good Solubility in water Not Miscible Very good to poor Not miscible Not miscible Seal swelling tendency Slight Shrinking Indifferent Fair Behaviour against paint Good Poor Good Good Biodegradability (CEC) % 10 to 30 10 to 99 70 to 100 10 to 100 Oxidation stability Good Good Fair Good Hydrolytic stability Good Poor Fair Sludge forming tendency Good Poor Fair Relative cost (Mineral oil = 1) 1 2 to 4 2 to 3 4 to 20