ATBECHDEDKESFRGBGRITLILUNLSEMCPTIESILTLVFIROMKCYALTRBGCZEEHU..SK................JDIM350 (Ver 2.1 Jan 2001) 1620000/01452581EUROPEAN PATENT APPLICATIONA320041222EP04250661.820040206EnEnEn37791520030227US20041222200452200409012004367 7C 10M 163/00 A 7C 10M 177/00 BdeVerfahren zur Verbesserung der ElastomerverträglichkeitenMethod for improving elastomer compatibilityfrProcédé d'amélioration de la compatibilité avec des élastomeresChevron Oronite Technology B.V.03891620P100988EP00/DANPetroleumweg 323196 KD Vondelingenplaat, RotterdamNLVan Leeuwen, JeroenZalmwater 432993 DX BarendrechtNLNash, David Allan00059255HASELTINE LAKE, Redcliff Quay 120 Redcliff StreetBristol BS1 6HUGBATBEBGCHCYCZDEDKEEESFIFRGBGRHUIEITLILUMCNLPTROSESISKTRALLTLVMK20041222200452

This invention relates to a method of improving elastomer seal compatibility and dispersancy in an internal combustion engine by contacting the elastomer seal in the internal combustion engine with a lubricating oil composition comprising:

a) a major amount of a base oil of lubricating viscosity;
b) a carboxylated detergent-dispersant obtained by:(i) neutralizing alkylphenols using an alkaline earth base in the presence of at least one carboxylic acid that contains from one to four carbon atoms but in the absence of alkali base, dialcohol, and monoalcohol, forming an intermediate product; and(ii) carboxylating the intermediate product using carbon dioxide so that at least 20 mole percent of the original alkylphenol starting material has been converted to alkaline earth metal single aromatic-ring hydrocarbyl salicylate; and
c) a nitrogen-containing dispersant.