Electrical Insulating Oil Compositions and Preparation Thereof

Abstract

An electrical insulating oil composition comprising a heavy reformate as an anti-gassing agent is provided with excellent gassing tendency. In one embodiment, the composition displays a gassing performance of <30 μL per minute as measured according to ASTM D-2300-1976. In a second embodiment, the composition displays a gassing performance of <0 μL per minute. In a third embodiment, the composition displays a negative gassing tendency as low as <−70 μL per minute.

1 . An electrical insulating oil composition in compliance with at least one of ASTM D 3487-2000 and IEC 60296-2003, the composition comprising
 (a) a base oil comprising at least one of a natural oil, a synthetic oil, an isomerized base oil, and mixtures thereof,   (b) 0.001 to 10 wt % at least an additive selected from an additive package, an oxidation inhibitor, anti-gassing agent, pour point depressant, metal deactivator, metal passivator, anti-foaming agent, and mixtures thereof, and   (c) a sufficient amount of a heavy reformate for the composition to have a gassing tendency of <30 μL per minute as measured according to ASTM D-2300-2300.   
   
   
       2 . The composition of  claim 1 , wherein the sufficient amount of heavy reformate is 0.10 to 15 wt. % based on the total weight of the composition. 
   
   
       3 . The composition of  claim 2 , wherein the sufficient amount of heavy reformate is 0.50 to 10 wt. % based on the total weight of the composition, for the composition to have a gassing tendency of <30 μL per minute as measured according to ASTM D-2300-1976. 
   
   
       4 . The composition of  claim 3 , wherein the sufficient amount of heavy reformate is 0.50 to 15 wt. % based on the total weight of the composition, for the composition to have a gassing tendency of <0 μL per minute as measured according to ASTM D-2300-1976. 
   
   
       5 . The composition of  claim 4 , wherein the sufficient amount of heavy reformate is 1 to 15 wt. % for the composition to have a gassing tendency of <−30 μL per minute as measured according to ASTM D-2300-1976. 
   
   
       6 . The composition of  claim 1 , wherein the heavy reformate has a boiling range of 300 to 500° F. (148-260° C.) and a Research Octane Number (RON) of 95 to 105. 
   
   
       7 . The electrical insulating oil composition of  claim 1 , wherein the electrical insulating oil displays a rotary pressure vessel oxidation stability (RPVOT) value of at least 400 minutes as measured according to ASTM D 2272-02. 
   
   
       8 . The electrical insulating oil composition of  claim 7 , wherein the electrical insulating oil displays a rotary pressure vessel oxidation stability (RPVOT) value of at least 500 minutes as measured according to ASTM D 2272-02. 
   
   
       9 . The composition of  claim 1 , wherein the base oil is selected from the group of a mineral oil, a vegetable oil, an oligomer of an alphaolefin, an ester, an oil derived from a gas-to-liquid process, a Fischer-Tropsch derived base oil, and mixtures thereof. 
   
   
       10 . The composition of  claim 9 , wherein the base oil comprises at least an isomerized base oil and 5 to 95 wt. % of at least one of a mineral oil, a vegetable oil, an oligomer of an alphaolefin, an ester, an oil derived from a gas-to-liquid process, and mixtures thereof. 
   
   
       11 . The electrical insulating oil composition of  claim 1 , wherein the lubricating base oil consists essentially of at least an isomerized base oil having a biodegradability of at least 60% as measured according to OECD 301D. 
   
   
       12 . The electrical insulating oil composition of  claim 11 , wherein the lubricating base oil consists essentially of at least an isomerized base oil having a biodegradability of at least 90% as measured according to OECD 301D. 
   
   
       13 . The electrical insulating oil composition of  claim 1 , wherein the lubricating base oil comprises an isomerized base oil having an auto-ignition temperature in ° C. (AIT) greater than an AIT in ° C. defined by: 1.6×(kinematic viscosity at 40° C., in mm 2 /s)+300. 
   
   
       14 . The electrical insulating oil composition of  claim 1 , wherein the lubricating base oil comprises an isomerized base oil having a traction coefficient less than an amount calculated by: 0.009×Ln (kinematic viscosity in mm 2 /S)-0.001, wherein the kinematic viscosity is the viscosity of the oil during the measurement of the traction coefficient. 
   
   
       15 . The electrical insulating oil composition of  claim 1 , wherein the lubricating base oil comprises an isomerized base oil having a Kinematic Vicosity at 100° C. of >1.808 mm 2 /s and a Noack volatility less than an amount calculated by the following equation: 1.286+20 (kv100) −1.5 +551.8 e −kv100 , where kv100 is the Kinematic Viscosity at 100° C. 
   
   
       16 . The electrical insulating oil composition of  claim 1 , wherein the additive is a pour point depressant selected from the group of pour point reducing blend components; polymethacrylates; polyacrylates; polyacrylamides; condensation products of haloparaffin waxes and aromatic compounds; vinyl carboxylate polymers; terpolymers of dialkylfumarates, vinyl esters of fatty acids, and alkyl vinyl ethers; and mixtures thereof. 
   
   
       17 . The electrical insulating oil composition of  claim 1 , wherein the additive is an antioxidant selected from the group consisting of phenolics, aromatic amines, compounds containing sulfur and phosphorus, organosulfur compounds, organophosphorus compounds, and mixtures thereof. 
   
   
       18 . The electrical insulating oil composition of  claim 1 , wherein the additive is a metal deactivator selected from the group consisting of triazoles, benzotriazoles, tolyltriazoles, tolyltriazole derivatives, and mixtures thereof. 
   
   
       19 . The electrical insulating oil composition of  claim 1 , wherein the lubricating base oil has a sulfur content of less than 10 ppm. 
   
   
       20 . An electrical equipment comprising the electrical insulating oil composition of  claim 1  for cooling and/or insulating. 
   
   
       21 . A medical equipment comprising the electrical insulating oil composition of  claim 1  for cooling and/or insulating. 
   
   
       22 . A method for improving the gassing tendency of an electrical insulating oil composition for the composition to have a gassing tendency of <−30 μL per minute as measured according to ASTM D-2300-197, the method comprising the step of adding 1 to 15 wt. % of a heavy reformate to a mixture of (a) a base oil selected from the group of a natural oil, a synthetic oil, a Fischer-Tropsch derived base oil, and mixtures thereof, and (b) 0.001 to 10 wt % at least an additive selected from an additive package, an oxidation inhibitor, anti-gassing agent, pour point depressant, metal deactivator, metal passivator, anti-foaming agent, and mixtures thereof. 
   
   
       23 . The method of  claim 22 , wherein 0.50 to 15 wt % of the heavy reformate is added to the mixture for the composition to have a gassing tendency of <0 μL per minute as measured according to ASTM D-2300-197.