All-weather tractor hydraulic fluid using a mixture of viscosity modifier types to meet shear-stable multigrade viscosity requirements

摘要

A composition of the following components: an oil of lubricating viscosity; a polymethacrylate viscosity modifier; an ester of a maleic acid/styrene copolymer; and optionally, an additive package that imparts to the fluid the capacity to meet bench and dynamometer tests specified by an equipment manufacturer, is suitable for use as a functional fluid such as a tractor hydraulic fluid, under a wide variety of climatic conditions.