The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 02, 1997
Filed:
Oct. 10, 1995
Frederick J Boden, Somerset, NJ (US);
Richard P Sauer, North Plainfield, NJ (US);
Irwin L Goldblatt, Edison, NJ (US);
Michael E McHenry, Washington, NJ (US);
Castrol Limited, Wiltshire, GB;
Abstract
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.