| 摘要 |
PROBLEM TO BE SOLVED: To obtain a lubricating oil compsn. which is excellent in capability for coexisting with a fluorocarbon elastomer by combining a lubricating oil contg. a dispersant of a posttreated or nonposttreated mono- or bissuccinimide type with a glycerin ester boride. SOLUTION: The glycerin ester boride is represented by the formula (wherein X is S or O; and R is a 3C or higher, pref. 3-50C, still pref. 3-17C, hydrocarbon group), a pref. example being a monooleic ester boride. The ratio (B/N) of boron (%) to basic nitrogen (%) of the dispersant in order to prevent cracks from occuring on the surface of the fluorocarbon elastomer is varied according to whether the additive contg. the bissuccinimide is posttreated or not. When the posttreatment is done with ethylene carbonate, the B/N ratio for decrasing the surface cracks is about 1; and when not posttreated, it is about 3. |
