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:
Feb. 25, 1992
Filed:
Jun. 01, 1989
Samuel Evans, Marly, CH;
Rolf Schumacher, Marly, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
Phosphite-free lubricating oil composition which comprises a) a mineral oil or a synthetic oil or a mixture thereof, and b) a mixture containing at least one aromatic amine of the formula (I), ##STR1## in which R.sup.1, R.sup.2, R.sup.3 and R.sup.3 ' are as defined in claim 1, and at least one phenol of the formula ##STR2## in which R.sup.4, R.sup.5 and A are as defined in claim 1, and the compounds are present in the mixture in a ratio of 2 to 6 parts by weight of the aromatic amine(s) of the formula I to 1 part by weight of the phenol(s) of the formula II. The lubricating oil compositions are highly resistant to ageing and are effective in preventing black sludge formation.