The present invention provides a lubricating oil composition comprising a lubricating base oil, and at least one ester additive selected from a first ester that is a fatty acid 3,4-epoxycyclohexyl alkyl ester and a second ester that is a 3,4-epoxycyclohexyl carboxylic acid alkyl ester, wherein a content of the ester additive is 0.01 to 5.0% by mass based on the total mass of the lubricating oil composition.

The invention relates to a use of a blend comprising an amphiphilic amine, and an amphiphilic acid for increasing the electric conductivity of a lubricant based on a hydrocarbon oil. The invention further relates to a method for increasing the electric conductivity of a lubricant based on a hydrocarbon oil comprising the step of contacting the hydrocarbon oil with a blend comprising the amphiphilic amine, and the an amphiphilic acid; and to a lubricant based on a hydrocarbon oil comprising a blend comprising the amphiphilic amine which is a compound of formula (A1) and the amphiphilic acid which is selected from compounds (B1), (B3), (B4), (B5), fatty acids, or alkylbenzene sulfonic acids.

The invention relates to a use of a blend comprising an amphiphilic amine, and an amphiphilic acid for increasing the electric conductivity of a lubricant based on a hydrocarbon oil. The invention further relates to a method for increasing the electric conductivity of a lubricant based on a hydrocarbon oil comprising the step of contacting the hydrocarbon oil with a blend comprising the amphiphilic amine, and the an amphiphilic acid; and to a lubricant based on a hydrocarbon oil comprising a blend comprising the amphiphilic amine which is a compound of formula (A1) and the amphiphilic acid which is selected from compounds (B1), (B3), (B4), (B5), fatty acids, or alkylbenzene sulfonic acids.