Patent ID: 8850875

Claim:
A method for evaluating the dispersibility of soot in a lubricant formulation which comprises at least one dispersant, comprising the steps of: (a) preparing a dispersion of carbon black in the lubricant formulation; (b) depositing a sample of the dispersed carbon black from step (a) onto a planar chromatography medium; (c) subjecting the sample of (b) to chromatographic conditions comprising introducing a liquid mobile phase to one side of said sample and permitting the liquid mobile phase to migrate past the sample of (b), thereby causing at least a portion of said carbon black to migrate in the direction of the migration of the liquid mobile phase; and (d) evaluating the extent of migration of said carbon black by comparing the density of darkening due to carbon black at pre-defined locations along the chromatography medium; wherein said liquid mobile phase comprises a mixture of: (i) a liquid hydrocarbon portion comprising a hydrocarbon having viscosity and boiling point less than that of an oil of lubricating viscosity; and (ii) an oil component comprising an oil of lubricating viscosity and the dispersant or dispersants that are also contained within the lubricant formulation.