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 D2300-08. In a second embodiment, the composition displays a gassing performance of <0 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 of an additive selected from an additive package which comprises one or more additives selected from the group consisting of 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-2300-08.   
     
     
         2 . The composition of  claim 1 , wherein the sufficient amount of heavy reformate is 0.10 to 6 wt. % based on the total weight of the composition. 
     
     
         3 . The composition of  claim 2 , having a flash point of at least 140° C. 
     
     
         4 . The composition of  claim 3 , wherein the sufficient amount of heavy reformate is from 0.1 to 2 wt. % based on the total weight of the composition, resulting in a composition having a gassing tendency of <30 ml per minute as measured according to ASTM D2300-08. 
     
     
         5 . The composition of  claim 4 , which does not comprise an additional anti-gassing agent. 
     
     
         6 . The composition of  claim 2 , wherein the sufficient amount of heavy reformate is from 0.10 to 0.50 wt. % based on the total weight of the composition, resulting in a composition having a gassing tendency of <30 μL per minute as measured according to ASTM D2300-08. 
     
     
         7 . The composition of  claim 6 , wherein the sufficient amount of heavy reformate is from 0.10 to 2 wt. % based on the total weight of the composition, resulting in a composition having a gassing tendency of <0 μL per minute as measured according to ASTM D2300-08. 
     
     
         8 . The composition of  claim 7 , wherein the sufficient amount of heavy reformate is 0.50 to 6 wt. % for the composition to have a gassing tendency of <−30 μL per minute as measured according to ASTM D2300-08. 
     
     
         9 . 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. 
     
     
         10 . 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 D2272-02. 
     
     
         11 . 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. 
     
     
         12 . The composition of  claim 11 , 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. 
     
     
         13 . 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. 
     
     
         14 . 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. 
     
     
         15 . 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. 
     
     
         16 . The electrical insulating oil composition of  claim 1 , wherein the lubricating base oil comprises an isomerized base oil having a Kinematic Viscosity 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. 
     
     
         17 . 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. 
     
     
         18 . 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. 
     
     
         19 . The electrical insulating oil composition of  claim 1 , wherein the lubricating base oil has a sulfur content of less than 10 ppm. 
     
     
         20 . 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 D2300-08, the method comprising the step of adding 0.1 to 6 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, a pour point depressant and mixtures thereof.