Grease composition for electrical contacts

Abstract

The present invention provides a grease composition for electrical contacts, including: a thickener; a base oil; and an organic sulfur compound, wherein the organic sulfur compound is a compound having no heterocycle containing nitrogen in a molecule thereof.

1 . A grease composition for electrical contacts, comprising a thickener, a base oil, and an organic sulfur compound, wherein the organic sulfur compound is a compound having no heterocycle containing nitrogen in a molecule thereof. 
     
     
         2 . The grease composition according to  claim 1 , wherein the organic sulfur compound is at least one selected from the group consisting of thiols, disulfides, alkylthiophenes, sulfides of oils or fats, sulfides of olefins, and thiophosphoric acid or esters thereof. 
     
     
         3 . The grease composition according to  claim 1 , wherein the organic sulfur compound is at least one selected from the group consisting of thiols. 
     
     
         4 . The grease composition according to  claim 1 , wherein the organic sulfur compound is a thiol having a linear or branched alkyl group having 6 to 24 carbon atoms. 
     
     
         5 . The grease composition according to  claim 1 , wherein the organic sulfur compound is stearyl mercaptan. 
     
     
         6 . The grease composition according to  claim 1 , wherein the organic sulfur compound is contained in an amount of about 0.001 to 5% by mass based on the total mass of the composition. 
     
     
         7 . The grease composition according to  claim 1 , wherein the base oil is a synthetic hydrocarbon oil. 
     
     
         8 . The grease composition according to  claim 1 , wherein the base oil is poly-alpha-olefin. 
     
     
         9 . The grease composition according to  claim 1 , wherein a kinematic viscosity of the base oil at 40° C. is about 200 mm 2 /s or less. 
     
     
         10 . The grease composition according to  claim 1 , wherein the base oil is contained in an amount of about 40 to 97% by mass based on the total mass of the composition. 
     
     
         11 . The grease composition according to  claim 1 , wherein the thickener is at least one selected from the group consisting of Li soaps, urea compounds, polytetrafluoroethylene, inorganic fine particles, and calcium sulfonate complex. 
     
     
         12 . The grease composition according to  claim 1 , wherein the thickener is polytetrafluoroethylene. 
     
     
         13 . The grease composition according to  claim 1 , wherein the thickener has a primary particle diameter of about 80 to 400 nm. 
     
     
         14 . The grease composition according to  claim 1 , wherein the thickener is contained in an amount of about 2 to 59% by mass based on the total mass of the composition. 
     
     
         15 . The grease composition according to  claim 1 , further comprising at least one additives selected from the group consisting of antioxidants, rust inhibitors, metal corrosion inhibitors, oiliness improvers, and viscosity index improvers. 
     
     
         16 . The grease composition according to  claim 15 , wherein the additive is contained in an amount of about 0.01 to 20% by mass based on the total mass of the composition. 
     
     
         17 . The grease composition according to  claim 1 , wherein the composition has a 60-stroke worked penetration measured according to JIS K2220 7 of about 220 to 400. 
     
     
         18 . The grease composition according to  claim 1 , wherein a material of the electrical contacts is gold or a gold alloy.