Dielectric fluid compositions comprising low viscosity monoesters with improved low temperature performance
The invention relates to branched monoesters of formula (I), as well as to a dielectric fluid composition, intended for use as a cooling fluid for electrical equipment systems, comprising at least one of these branched monoesters of formula (I). The invention is also directed to a method of cooling electrical equipment systems by using the dielectric fluid compositions according to the invention.
1 . A branched monoester A), wherein the branched monoester A) is of formula (I)
wherein R 1 is a linear alkyl residue with 3 to 13 carbon atoms,
wherein each R 2 and R 3 is a linear alkyl residue with 5 carbon atoms, and
the branched monoester A) does not include 6-undecyl laurate.
2 . The branched monoester A) according to claim 1 , wherein R 1 is a linear alkyl residue with 5 to 10 carbon atoms.
3 . The branched monoester A) according to claim 1 , wherein the branched monoester A) is selected from the group consisting of 6-undecylhexanoate, 6-undecyloctanoate and mixtures thereof.
4 . A dielectric fluid composition, wherein the dielectric fluid composition comprises a branched monoester A) as defined in claim 1 , or a mixture thereof.
5 . The dielectric fluid composition according to claim 4 , wherein the dielectric fluid composition further comprises a base fluid B) selected from the group consisting of polyol ester, saturated hydrocarbon, dicarboxylic acid ester, carbonate, ether, alcohol and mixtures thereof.
6 . The dielectric fluid composition according to claim 4 , wherein the dielectric fluid composition further comprises an additive C) selected from the group consisting of defoamers, seal compatibility agents, antioxidants, yellow metal passivators, rust inhibitors, electrostatic discharge depressants, demulsifiers, dyes and mixtures thereof.
7 . The dielectric fluid composition according to claim 4 , wherein the dielectric fluid composition comprises 2 to 100% by weight of branched monoester A), 0 to 98% by weight of base fluid B), and 0 to 5% by weight of additive C), based on the total weight of the dielectric fluid composition.
8 . The dielectric fluid composition according to claim 7 , wherein the amounts of A) to C) add up to at least 90% by weight, based on the total weight of the dielectric fluid composition.
9 . A method of cooling an electrical equipment system comprising applying a dielectric fluid composition to the electrical equipment system,
wherein the dielectric fluid composition comprises a branched monoester A) of formula (I), or a mixture thereof:
wherein R 1 is a linear alkyl residue with 3 to 13 carbon atoms, and
wherein each R 2 and R 3 is a linear alkyl residue with 5 carbon atoms.
10 . The method according to claim 9 , wherein the dielectric fluid composition is applied to the electrical equipment system by direct liquid immersion.
11 . The method according to claim 9 , wherein R 1 is a linear alkyl residue with 5 to 11 carbon atoms.
12 . The method according to claim 9 , wherein the branched monoester A) is 6-undecyllaurate, 6-undecylhexanoate, 6-undecyloctanoate or a mixture thereof.
13 . The method according to claim 9 , wherein the dielectric fluid composition further comprises a base fluid B) selected from the group consisting of polyol ester, saturated hydrocarbon, dicarboxylic acid ester, carbonate, ether, alcohol and mixtures thereof.
14 . The method according to claim 9 , wherein the dielectric fluid composition further comprises an additive C) selected from the group consisting of defoamers, seal compatibility agents, antioxidants, yellow metal passivators, rust inhibitors, electrostatic discharge depressants, demulsifiers, dyes and mixtures thereof.
15 . The method according to claim 9 , wherein the dielectric fluid composition comprises 2 to 100% by weight of branched monoester A), 0 to 98% by weight of base fluid B), and 0 to 5% by weight of additive C), based on the total weight of the dielectric fluid composition.
16 . The method according to claim 15 , wherein the amounts of A) to C) add up to at least 90% by weight, based on the total weight of the dielectric fluid composition.