Abstract:
Highly useful hydraulic fluids based on synthetic hydrocarbon basestocks and having improved low temperature properties, good shear stability, and capable of substantially meeting the rigid Denison HF-O standards are provided. The products of this invention are comprised of specific proportions of a two centistoke synthetic hydrocarbon oil obtained from the oligomerization of alpha-olefins, particularly 1-decene, specific polymethacrylate viscosity index improvers, and a zinc-based universal/multifunctional additive package. The hydraulic fluids have a maximum viscosity of 1400 centistokes at -40. degree. F. and minimum viscosity of 5. 5 centistokes at 210. degree. F.