Lubricant composition based on metal nanoparticles

Abstract

The present invention relates to a lubricant composition comprising a dispersant of high molecular weight and metal nanoparticles. The lubricant composition according to the invention simultaneously has good stability and good anti-flaking properties.

1 . A lubricant composition comprising at least one base oil, at least one dispersant having a weight-average molecular weight greater than or equal to 2000 Daltons and metal nanoparticles in a content by weight ranging from 0.01 to 2% with respect to the total weight of the lubricant composition, the metal nanoparticles being concentric polyhedrons with a multilayer or sheet structure. 
     
     
         2 . The lubricant composition according to  claim 1  in which the metal of which the metal nanoparticle is constituted is selected from the group formed by tungsten, molybdenum, zirconium, hafnium, platinum, rhenium, titanium, tantalum, niobium, zinc, cerium, aluminium, indium and tin. 
     
     
         3 . The lubricant composition according to  claim 1  in which the metal nanoparticles are selected from the group formed by MoS 2 , MoSe 2 , MoTe 2 , WS 2 , WSe 2 , ZrS 2 , ZrSe 2 , HfS 2 , HfSe 2 , PtS 2 , ReS 2 , ReSe 2 , TiS 3 , ZrS 3 , ZrSe 3 , HfS 3 , HfSe 3 , TiS 2 , TaS 2 , TaSe 2 , NbS 2 , NbSe 2  and NbTe 2 . 
     
     
         4 . The lubricant composition according to  claim 1  in which the content by weight of metal nanoparticles ranges from 0.05 to 2% with respect to the total weight of the lubricant composition. 
     
     
         5 . The lubricant composition  claim 1  in which the average size of the metal nanoparticles ranges from 5 to 600 nm. 
     
     
         6 . The lubricant composition according to  claim 1  in which the dispersant is selected from the compounds comprising at least one succinimide group, the polyolefins, the olefin copolymers, the copolymers comprising at least one styrene unit, the polyacrylates or derivatives thereof. 
     
     
         7 . The lubricant composition according to  claim 1  in which the dispersant is selected from the compounds comprising at least one substituted succinimide group or the compounds comprising at least two substituted succinimide groups, the succinimide groups being linked at their carbon-containing vertex bearing a nitrogen atom by a polyamine group. 
     
     
         8 . The lubricant composition according to  claim 1  in which the dispersant has a weight-average molecular weight ranging from 2000 to 15000 Daltons. 
     
     
         9 . The lubricant composition according to  claim 1  in which the dispersant also has a number-average molecular weight greater than or equal to 1000 Daltons. 
     
     
         10 . The lubricant composition according to  claim 1  in which the content by weight of dispersant ranges from 0.1 to 10% with respect to the total weight of the lubricant composition. 
     
     
         11 . The lubricant composition according to  claim 1  in which the base oil is selected from the poly alpha olefins or the esters or mixtures thereof. 
     
     
         12 . The lubricant composition according to  claim 1  also comprising at least one additional additive selected from the polymeric viscosity index improvers and the antioxidants or mixtures thereof, the polymeric viscosity index improvers being selected from the ethylene and alpha-olefin copolymers. 
     
     
         13 . The lubricant composition according to  claim 12  in which the additional additive is an antioxidant selected from the dialkylphenylamines, phenolic antioxidants or mixtures thereof. 
     
     
         14 . (canceled) 
     
     
         15 . A method for lubricating gearboxes or axles, the method comprising adding a lubricant composition into gearboxes or axles, the lubricant composition comprising at least one base oil, at least one dispersant having a weight-average molecular weight greater than or equal to 2000 Daltons and metal nanoparticles in a content by weight ranging from 0.01 to 2% with respect to the total weight of the lubricant composition, the metal nanoparticles being concentric polyhedrons with a multilayer or sheet structure. 
     
     
         16 . The method according to  claim 15  for which wherein the gearbox is a manual gearbox. 
     
     
         17 . A method for reducing the flaking of a mechanical part, the method comprising adding a lubricant composition into the mechanical part, the lubricant composition comprising at least one base oil, at least one dispersant having a weight-average molecular weight greater than or equal to 2000 Daltons and metal nanoparticles in a content by weight ranging from 0.01 to 2% with respect to the total weight of the lubricant composition, the metal nanoparticles being concentric polyhedrons with a multilayer or sheet structure. 
     
     
         18 . The method according to  claim 17  wherein the mechanical part is a manual gearbox. 
     
     
         19 . (canceled)