Process oil, high-viscosity base oil, and process for the production thereof

摘要

A novel process for the production of an extract useful as a process oil and a raffinate useful as a high-viscosity base oil by solvent refining is provided, characterized in that reduced pressure distillation is effected under the condition that the end point of distillate is 580° C. or higher as calculated in terms of atmospheric pressure or the initial boiling point of the residue is 450° C. or higher as calculated in terms of atmospheric pressure, the resulting residual oil is deasphalted under the condition that the carbon residue content in the deasphalted oil reached 1.6% or less, and the resulting deasphalted oil is subjected to solvent refining under the condition that the yield of extract is from 35% to 60%. It is a novel and economically excellent process for the preparation of a rubber process oil having a high safety, a high penetrating power with respect to rubber polymer and the content of PCA extract of less than 3%.