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:
Jun. 16, 2009
Filed:
Dec. 21, 2005
William Loh, Petaluma, CA (US);
John Rosenbaum, Richmond, CA (US);
Nancy J. Bertrand, Lafayette, CA (US);
Patricia Lemay, Vallejo, CA (US);
Rawls Frazier, Petaluma, CA (US);
Mark E. Okazaki, Alameda, CA (US);
William Loh, Petaluma, CA (US);
John Rosenbaum, Richmond, CA (US);
Nancy J. Bertrand, Lafayette, CA (US);
Patricia LeMay, Vallejo, CA (US);
Rawls Frazier, Petaluma, CA (US);
Mark E. Okazaki, Alameda, CA (US);
Chevron U.S.A. Inc., San Ramon, CA (US);
Abstract
An ashless hydraulic fluid or paper machine oil having a VI between 155 and 300, a RPVOT greater than 680 minutes, and a kinematic viscosity at 40° C. from 19.8 cSt to 748 cSt. An ashless hydraulic fluid or paper machine oil having a high VI and high RPVOT comprising: a) a Group III base oil with a sequential number of carbon atoms, and defined cycloparaffin composition or low traction coefficient, b) an ashless antioxidant additive concentrate, and c) low amount of VI improver. A process for making an ashless hydraulic fluid or paper machine oil comprising a) hydroisomerization dewaxing, b) fractionating, c) selecting a fraction having a very high VI, and a high level of molecules with cycloparaffinic functionality or a low traction coefficient, and d) blending the fraction with an ashless antioxidant. Also, a method of improving the oxidation stability of an ashless hydraulic fluid or paper machine oil.