Patent ID: 8753549

Claim:
A dielectric fluid comprising: (a) an oil selected from the group consisting of algae oils, fatty acid esters, microbial oil, mineral oils, vegetable-based oils, and vegetable seed oils and; (b) a substituted, hindered phenolic antioxidant having at least two substituted cresol groups being covalently bonded to each other through a methylene bridge of the structure wherein R1-R10 is a hydrogen, a hydroxyl group, an alkyl group, an alkenyl group, an alkoxy group, or an aryl group and where at least one of R1-R5 and at least one of R6-R10 is an hydroxyl group, at least one of R1-R5 and at least one of R6-R10 is a methyl group, and at least one of R1-R5 and at least one of R6-R10 is an alkyl, alkenyl, or alkoxy group that may be straight-chained or branched or an aryl group and the alkyl, alkenyl, alkoxy, or aryl group may be substituted or unsubstituted; and (c) a substituted, diphenyl amine antioxidant having at least two substituted phenyl groups being covalently bonded to each other through an amine bridge of the structure wherein R1-R10 is, independently, a hydrogen, an alkyl group, an alkenyl group, an alkoxy group, an aryl group or a vinyl benzyl group, when R1-R10 is an alkyl group, an alkenyl group, or an alkoxy group that group may be straight-chained or branched and may be substituted or unsubstituted, and when R1-R10 is an aryl group that group may be substituted or unsubstituted.