Grease composition

Abstract

The invention relates to a fatty composition including at least one basic polyol ester oil, at least one fatty-acid metal soap, at least one fluorinated polymer, and at least one sulfurous fatty acid ester, wherein the amount of active sulfur provided by the sulfurous fatty acid ester relative to the total fatty composition at 150° C. according to the ASTM D1662 standard is greater than or equal to 0.15 wt %.

1 . A grease composition comprising at least one base oil of the polyol ester type, at least one fatty-acid metal soap, at least one fluorine-containing polymer and at least one sulfurized fatty acid ester, the quantity by mass of active sulphur at 150° C. according to standard ASTM D1662 provided by the sulfurized fatty acid ester with respect to the total mass of grease composition being greater than or equal to 0.15%. 
     
     
         2 . The composition according to  claim 1 , in which the polyol ester is selected from the group consisting of neopentylglycol esters, trimethylolethane esters, trimethylolpropane esters, pentaerythritol esters, dipentaerythritol esters, and combinations thereof. 
     
     
         3 . The composition according to  claim 1 , comprising from 50 to 95% by mass with respect to the total mass of grease composition of a base oil of the polyol ester type. 
     
     
         4 . The composition according to  claim 1 , in which the fluorine-containing polymer is polytetrafluoroethylene. 
     
     
         5 . The composition according to  claim 1 , comprising from 1 to 10% by mass of fluorine-containing polymer with respect to the total mass of grease composition. 
     
     
         6 . The composition according to  claim 1 , in which the sulfurized fatty acid ester is a fatty acid triglyceride, a fatty acid methyl ester and combinations thereof. 
     
     
         7 . The composition according to  claim 1 , comprising from 0.5 to 5% by mass of sulfurized fatty acid ester with respect to the total mass of grease composition. 
     
     
         8 . The composition according to  claim 1 , in which the fatty-acid metal soap is a simple fatty-acid metal soap. 
     
     
         9 . The composition according to  claim 1 , in which the fatty-acid metal soap is lithium 12-hydroxystearate. 
     
     
         10 . The composition according to  claim 1 , comprising from 1 to 20% by mass with respect to the total mass of the grease composition of fatty-acid metal soap. 
     
     
         11 . The composition according to  claim 1 , in which the polyol ester, or the mixture of polyol esters, has a kinematic viscosity at 40° C., measured according to standard ASTM D 445, comprised between 3 and 2000 cSt. 
     
     
         12 . The composition according to  claim 1 , having a consistency according to standard ASTM D217 comprised between 220 and 430 tenths of a millimetre. 
     
     
         13 . The composition according to  claim 1 , comprising a quantity by mass of active sulphur at 150° C. according to standard ASTM D1662 provided by the sulfurized fatty acid ester with respect to the total mass of grease composition, greater than or equal to 0.18% by mass. 
     
     
         14 . The composition according to  claim 1 , having a welding load according to standard ASTM D2596 greater than 315 kg. 
     
     
         15 . The composition according to  claim 1 , having a welding load according to standard DIN 51350/4 greater than 300 daN. 
     
     
         16 . The composition according to  claim 1 , having a classification of corrosiveness to copper according to standard ASTM D4048 of 1 or 2. 
     
     
         17 . A method of using a grease composition providing comprising at least one base oil of the polyol ester type and at least one fatty-acid metal soap, at least one fluorine-containing polymer and at least one sulfurized fatty acid ester, the quantity by mass of active sulphur at 150° C. according to standard ASTM D1662 provided by the sulfurized fatty acid ester being greater than or equal to 0.15% with respect to the total mass of grease composition, and improving extreme-pressure performance according to standards ASTM D2596 and/or DIN 51350/4 of the grease composition. 
     
     
         18 . The composition according to  claim 8 , wherein the simple fatty-acid metal soap is selected from the group consisting of a fatty-acid lithium soap, a fatty-acid calcium soap and combinations thereof.