Patent ID: 6110879
Filing Date: 2000-08-29
Classification: C10M,C10N

Abstract:
A lubricating composition comprising:(a) a major amount of a base oil mixture comprising:(1) from about 0 wt. % to about 90 wt. % of a first mineral oil selected from a high viscosity index mineral oil, a conventional low viscosity index mineral oil, and mixtures thereof; and(2) from about 10 wt. % to about 100 wt. % of a second mineral oil comprising a hydrocracker-derived, highly naphthenic, low viscosity index mineral oil prepared by:(i) passing a first bottoms portion comprising not more than about 67 wt. % of a fuels hydrocracker bottoms recycle stream to a dewaxing zone; and passing a second bottoms portion comprising at least about 33 wt. % of said recycle stream back to said fuels hydrocracker for additional processing; and wherein said recycle stream has a viscosity at 100.degree. C. of less than about 4.0;(ii) contacting said first bottoms portion with a dewaxing catalyst under catalytic dewaxing conditions, wherein at least a portion of said hydrocracker bottoms is substantially dewaxed;(iii) contacting at least a portion of said substantially dewaxed hydrocracker bottoms with a hydrofinishing catalyst under hydrofinishing conditions, thereby producing a hydrofinished, dewaxed hydrocracker bottoms; and(iv) removing from said hydrofinished, dewaxed hydrocracker bottoms at least one light fraction comprising diesel or jet fuel range material, thereby leaving a heavy fraction comprising said hydrocracker-derived, highly naphthenic, viscosity index mineral oil having a naphthenes content of at least about 33 wt. %;(b) from about 2 wt. % to about 14 wt. % of at least one polymethacrylate polymer;(c) from about 2 wt. % to about 14 wt. % of a performance additive package; and(d) wherein said lubricating composition has:(1) an unsheared kinematic viscosity at 100.degree. C. of at least about 7.3 centistokes;(2) a sheared kinematic viscosity at 100.degree. C. of at least about 6.8 centistokes, wherein shear is measured by the 20 hour KRL method; and(3) a Brookfield viscosity at -40.degree. C. of no greater than about 10,000 centipoise.