Castrol Limited

Frederick J Boden

Irwin L Goldblatt

Richard P Sauer

Michael E McHenry

A grafted polyolefin containing one or more of N-vinylimidazole, 4-vinylpyridine, or other ethylenically-unsaturated nitrogen-containing or oxygen-containing graftable monomers grafted to a polyolefin copolymer is disclosed. The grafted polyolefin preferably has a weight average molecular weight of from about 20,000 to about 500,000, a polydispersity of less than about 10, and an ADT value of at least about 8. The grafted polyolefin can be defined as containing more than about 1.2% by weight of grafted monomer on a polyolefin, or as containing at least about 13 moles of graftable monomers per mole of polyolefin, or as having an asphaltene dispersancy test (ADT) value of at least about 8. Also described is a lubricating oil comprising a lubricant base oil and a grafted polyolefin as described above. Also described is a method of making a dispersant viscosity index improver. N-vinyl-imidazole or other ethylenically unsaturated nitrogen-containing and/or oxygen-containing graftable monomers and a graftable polyolefin are reacted with enough of an initiator to graft the monomer to the polyolefin. The initiator and/or graftable monomer is added to the other ingredients, maintained at the reaction temperature, over a period of time. The reaction temperature is maintained at a level high enough to give acceptable reaction times. The N-vinylimidazole and the initiator each can be added at a uniform, relatively slow rate during the reaction.

Polar grafted polyolefins, methods for their manufacture, and lubricating oil compositions containing them

A grafted polyolefin containing one or more of N-vinylimidazole, 4-vinylpyridine, or other ethylenically-unsaturated nitrogen-containing or oxygen-containing graftable monomers grafted to a polyolefin copolymer is disclosed. The grafted polyolefin preferably has a weight average molecular weight of from about 20,000 to about 500,000, a polydispersity of less than about 10, and an ADT value of at least about 8. The grafted polyolefin can be defined as containing more than about 1.2% by weight of grafted monomer on a polyolefin, or as containing at least about 13 moles of graftable monomers per mole of polyolefin, or as having an asphaltene dispersancy test (ADT) value of at least about 8. Also described is a lubricating oil comprising a lubricant base oil and a grafted polyolefin as described above. Also described is a method of making a dispersant viscosity index improver. N-vinylimidazole or other ethylenically unsaturated nitrogen-containing and/or oxygen-containing graftable monomers and a graftable polyolefin are reacted with enough of an initiator to graft the monomer to the polyolefin. The initiator and/or graftable monomer is added to the other ingredients, maintained at the reaction temperature, over a period of time. The reaction temperature is maintained at a level high enough to give acceptable reaction times. The N-vinylimidazole and the initiator each can be added at a uniform, relatively slow rate during the reaction.

Polar grafted polyolefins, methods for their manufacture, and

A grafted polyolefin containing at least about 13 moles of N-vinylimidazole or other ethylenically-unsaturated nitrogen-containing and/or oxygen-containing monomers per mole of a grafted polyolefin backbone is disclosed. The graft polyolefin has a weight average molecular weight of from about 20,000 to about 500,000 and a polydispersity of less than about 10. The grafted polyolefin can alternatively be defined as containing more than about 1.2% by weight of grafted monomer on a polyolefin. Also described is a lubricating oil comprising a lubricant base oil and a grafted polyolefin as described above. Also described is a method of making a dispersant-viscosity index improver. N-vinylimidazole or other ethylenically unsaturated nitrogen-containing and/or oxygen-containingmonomers and a graftable polyolefin are reacted with enough of an initiator to graft at least about 13 moles of the monomer to each mole of the polyolefin. The initiator and/or monomer is added to the other ingredients, maintained at the reaction temperature, over a period of time. The reaction temperature is maintained at a level high enough to give acceptable reaction times. In one embodiment, the N-vinylimidazole and the initiator are each added at a uniform, relatively slow rate during the reaction.

A grafted polyolefin containing N-vinylimidazole, 4-vinylpyridine, or other ethylenically-unsaturated nitrogen- or oxygen-containing graftable monomers grafted to a polyolefin copolymer. The grafted polyolefin preferably has a weight average molecular weight of from about 20,000 to about 500,000 and a polydispersity of less than about 10. The grafted polyolefin can contain more than about 1.2% by weight of grafted monomer or 13 or more moles of graftable monomers per mole of polyolefin and have an asphaltene dispersancy test (ADT) value of at least about 8. Also described is a lubricating oil comprising such a grafted polyolefin. Also described is a method of making a grafted polyolefin dispersant viscosity index improver by adding the graft monomer or the initiator slowly during the reaction. The present reaction can optionally be carried out by providing a melted reactant composition in an extruder or other polymeric mixer.

A grafted polyolefin containing at least about 13 moles of N-vinylimidazole or other ethylenically-unsaturated nitrogen-containing and/or oxygen-containing monomers per mole of a grafted polyolefin backbone is disclosed. The graft polyolefin has a weight average molecular weight of from about 20,000 to about 500,000 and a polydispersity of less than about 10. The grafted polyolefin can alternatively be defined as containing more than about 1.2% by weight of grafted monomer on a polyolefin. Also described is a lubricating oil comprising a lubricant base oil and a grafted polyolefin as described above. Also described is a method of making a dispersant-viscosity index improver. N-vinylimidazole or other ethylenically unsaturated nitrogen-containing and/or oxygen-containing monomers and a graftable polyolefin are reacted with enough of an initiator to graft at least about 13 moles of the monomer to each mole of the polyolefin.

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Somerset, NJ, United States of America

Frederick J Boden