Wax and Low Temperature Engine Oil Pumpability

The wax crystallization process is an important factor in tow temperature engine pumpability, and one key parameter of this process is wax composition. Lube oil wax is a mixture of three paraffin types: each one with its own concentration and carbon number distribution. The latter is dependent upon the boiling point range of the basestock and the wax precipitation temperature as well as the degree of dewaxing. The paraffin types are homologous when one basestock is used to formulate a 10W base oil, but when two basestocks are present, the wax is a dumbbell mixture of these paraffins. These 10W base oils have different rheological properties—yield stress and apparent viscosity. However, in the presence of a flow improver, these base oils have similar rheological behavior.