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:
Apr. 12, 1994
Filed:
Oct. 01, 1993
Robert B Rhodes, Houston, TX (US);
Arthur R Bean, Houston, TX (US);
Shell Oil Company, Houston, TX (US);
Abstract
An improved VI improver and a fluid composition comprising the VI improver. The VI improver is an asymmetric radial polymer comprising a plurality of arms having at least two distinctly different peak molecular weights, which arms are chemically the same. The weight ratio of a longest set of arms and a first set of shorter arms will vary within the range from about 1.2:1 to about 8.0:1. If more than one set of shorter arms is used the ratio of adjacent arms molecular weights will vary within the same range. While the arm might be essentially any polymer, polymers of conjugated diolefins and copolymers of at least one monoalkenyl aromatic hydrocarbon and at least one conjugated diolefin are preferred. Conjugated diolefin homopolymers are preferred and polyisoprene is most preferred.