Dielectric fluids comprising natural bio-sourced oil with increased stability
A dielectric fluid is provided comprising a natural bio-sourced oil and one or more compounds selected from the group consisting of phosphite compounds. It has been discovered that addition of one or more compounds selected from the group consisting of phosphite compounds to dielectric fluids comprising oil impart a stabilizing effect that reduces, inhibits or prevents formation of stray gases in the dielectric fluid during ordinary use.
1 . A dielectric fluid comprising a natural bio-sourced oil, a phosphite component comprising one or more phosphite compounds, a non-phosphite antioxidant component selected from one or more non-phosphite antioxidant compounds and a metal passivator, wherein the phosphite component is selected from phosphite compounds having one to three aryloxy groups, the non-phosphite antioxidant component is butylated phenol and the metal passivator is benzotriazole or its derivatives, and wherein the natural bio-sourced oil is soybean oil,
and wherein the phosphite component is present in an amount sufficient to reduce the stray gassing of the dielectric fluid as determined by dissolved gas analysis by at least 60% as compared to a like dielectric fluid composition that does not contain a phosphite component, wherein the stray gas is H 2 , ethane, methane or ethylene, wherein the gas analysis is conducted by ATSM D3612-02, Method C.
2 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount sufficient to reduce an H 2 gassing of the dielectric fluid by at least 60% as compared to a like dielectric fluid composition that does not contain a phosphite component.
3 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount sufficient to reduce an H 2 gassing of the dielectric fluid by at least 70% as compared to a like dielectric fluid composition that does not contain a phosphite component.
4 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount sufficient to reduce an H 2 gassing of the dielectric fluid by at least 80% as compared to a like dielectric fluid composition that does not contain a phosphite component.
5 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount of from 0.05 to a limit of solubility in the dielectric fluid.
6 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount of from 0.1 to a limit of solubility in the dielectric fluid.
7 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount of from 0.05 to 1.5% wt.
8 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount of from 0.05 to 1% wt.
9 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount of from 0.05 to 0.5% wt.
10 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount of from 0.1 to 4% wt.
11 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount of from 0.1 to 1% wt.
12 . The dielectric fluid of claim 1 , wherein the phosphite component is present in an amount of from 0.1 to 0.5% wt.
13 . The dielectric fluid of claim 1 , wherein the phosphite component is selected from the group consisting of phosphite esters, triarylphosphites, trialkylphosphites, cyclic phosphites, and bis-arylphosphite pentaerythritol cyclic esters.
14 . The dielectric fluid of claim 1 , wherein the phosphite component is selected from triaryl phosphite compounds.
15 . The dielectric fluid of claim 1 , wherein the non-phosphite antioxidant component is selected from the group consisting of butylated hydroanisole; butylated hydrotoluene; tertiary butylhydroquinone; tetrahydrobutrophenone; ascorbyl palmitate; propyl gallate; alpha-, beta-or delta-tocopherol; and mixtures thereof.
16 . The dielectric fluid of claim 1 , wherein the non-phosphite antioxidant component is selected from the group consisting of Pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); Hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; Octadecyl-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; Ethylene bis(oxyethylene) bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate); 2,6-Di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol; N,N′-hexane-1,6-diylbi(3-3,5-di-tert-butyl-4-hydroxyphenylpropionamide); 4,6-Bis(octylthiomethyl)-o-cresol; 4,4′-methylene-bis-2,6-di-tert.-butyl phenol; and 2,6-Di-tert-butyl-4-methylphenol.
17 . The dielectric fluid of claim 1 , wherein the metal passivator is present in amount sufficient to control the dissipation value of the dielectric fluid as determined by IEC 60247 (120° C.) at or below 0.50 at 48 hours of oxidative stability testing as evaluated in accordance with by IEC 61125 Method C.
18 . The dielectric fluid of claim 1 , wherein the metal passivator is present in amount sufficient to control the dissipation value of the dielectric fluid as determined by IEC 60247 (120° C.) at or below 0.60 at 48 hours of oxidative stability testing as evaluated in accordance with by IEC 61125 Method C.
19 . The dielectric fluid of claim 1 , wherein the metal passivator is present in amount sufficient to control the dissipation value of the dielectric fluid as determined by IEC 60247 (120° C.) at or below 0.90 at 48 hours of oxidative stability testing as evaluated in accordance with by IEC 61125 Method C.
20 . The dielectric fluid of claim 1 , wherein the metal passivator is present in amount sufficient to control the dissipation value of the dielectric fluid as determined by IEC 60247 (120° C.) at or below 1.0 at 48 hours of oxidative stability testing as evaluated in accordance with by IEC 61125 Method C.
21 . The dielectric fluid of claim 1 , wherein the metal passivator is present in amount of from 0.005 to 1.0% wt.
22 . The dielectric fluid of claim 1 , wherein the metal passivator is selected from the group consisting of N,N-bis(2-ethylhexyl)-ar-methyl-1H-Benzotriazole-1-methanamine; N,N-bis(2-ethylhexyl)-1H-1,2,4-Triazole-1-methanamine; 1H-Benzotriazole; Methyl-1H-benzotriazole; and 2,2′-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bis-ethanol.