Friction and wear reduction using liquid crystal base stocks

Abstract

A method for improving friction and wear control, while maintaining or improving energy efficiency, in an engine or other mechanical component lubricated with a lubricating oil, by using as the lubricating oil a formulated oil. The formulated oil has a composition including at least one lubricating oil base stock. The at least one lubricating oil base stock includes one or more liquid crystals, wherein the one or more liquid crystals are represented by the formula: A−(R 1 ) n wherein A is a mono-ring or a multi-ring aromatic group, R1 is the same or different and is a substituted or unsubstituted, hydrocarbon, alkoxy, or alkylthio group having from 2 to 24 carbon atoms, and n is a value from 1 to 12. The lubricating oil base stock has a kinematic viscosity of 2 cSt to 200 cSt at 40° C., as determined according to ASTM D445, and a kinematic viscosity of 1 cSt to 25 cSt at 100° C., as determined according to ASTM D445.

1 . A lubricating oil base stock comprising one or more liquid crystals, wherein the one or more liquid crystals are represented by the formula:
   A—(R1) n  
   
       wherein A is a mono-ring or a multi-ring aromatic group, R1 is the same or different and is a substituted or unsubstituted, hydrocarbon group, alkoxy, or alkylthio having from about 2 to about 24 carbon atoms, and n is a value from about 1 to about 12; and wherein the lubricating oil base stock has a kinematic viscosity of about 2 cSt to about 200 cSt at 40° C., as determined according to ASTM D445, and a kinematic viscosity of about 1 cSt to about 25 cSt at 100° C., as determined according to ASTM D445. 
     
     
         2 . The lubricating oil base stock of  claim 1  wherein, in friction coefficient measurements of the lubricating oil base stock by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction) test machine, Verschleiž (wear) (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.25. 
     
     
         3 . The lubricating oil base stock of  claim 1  wherein, in friction coefficient measurements of the lubricating oil base stock by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction), Verschleiž (wear) test machine (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.20. 
     
     
         4 . The lubricating oil base stock of  claim 1  wherein, in friction coefficient measurements of the lubricating oil base stock by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction), Verschleiž (wear) test machine (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.10. 
     
     
         5 . The lubricating oil base stock of  claim 1  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=W[Temperature(C)/Load 2 (N)] z , where W and Z are both independently constant integers of less than 1 and greater than zero value. 
     
     
         6 . The lubricating oil base stock of  claim 1  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=0.08[Temperature(C)/Load2(N)] 0.4 . 
     
     
         7 . The lubricating oil base stock of  claim 1  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=Y[Load(N)] X , where Y is a constant integer of less than 1 and X value is less than zero. 
     
     
         8 . The lubricating oil base stock of  claim 1  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=0.4[Load(N)] −0.8 . 
     
     
         9 . The lubricating oil base stock of  claim 1  wherein the one or more liquid crystals are represented by the formula: 
       
         
           
           
               
               
           
         
       
     
     
         10 . The lubricating oil base stock of  claim 1  wherein the one or more liquid crystals comprise hexakis(octylthio)benzene. 
     
     
         11 . The lubricating oil base stock of  claim 1  further comprising one or more of an antiwear additive, viscosity modifier, antioxidant, detergent, dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, or anti-rust additive. 
     
     
         12 . The lubricating oil base stock of  claim 1  which is a machining or pre-run fluid for smoothing and conforming mated metal surfaces. 
     
     
         13 . A method for improving friction and wear control, while maintaining or improving energy efficiency, in an engine or other mechanical component lubricated with a lubricating oil, by using as the lubricating oil a formulated oil, said formulated oil having a composition comprising at least one lubricating oil base stock; wherein the at least one lubricating oil base stock comprises one or more liquid crystals, wherein the one or more liquid crystals are represented by the formula:
   A—(R1) n  
   
       wherein A is a mono-ring or a multi-ring aromatic group, R1 is the same or different and is a substituted or unsubstituted, hydrocarbon, alkoxy, or alkylthio group having from about 2 to about 24 carbon atoms, and n is a value from about 1 to about 12; and wherein the lubricating oil base stock has a kinematic viscosity of about 2 cSt to about 200 cSt at 40° C., as determined according to ASTM D445, and a kinematic viscosity of about 1 cSt to about 25 cSt at 100° C., as determined according to ASTM D445; and wherein friction and wear control are improved and energy efficiency is maintained or improved as compared to friction control, wear control and energy efficiency achieved using a lubricating oil containing a lubricating oil base stock other than the lubricating oil base stock comprising one or more liquid crystals. 
     
     
         14 . The method of  claim 13  wherein, in friction coefficient measurements of the lubricating oil base stock by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction), Verschleiž (wear) test machine (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.25. 
     
     
         15 . The method of  claim 13  wherein, in friction coefficient measurements of the lubricating oil base stock by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction), Verschleiž (wear) test machine (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.20. 
     
     
         16 . The method of  claim 13  wherein, in friction coefficient measurements of the lubricating oil base stock by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction), Verschleiž (wear) test machine (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.10. 
     
     
         17 . The method of  claim 13  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=W[Temperature(C)/Load 2 (N)] z , where W and Z are both independently constant integers of less than 1 and greater than zero value. 
     
     
         18 . The method of  claim 13  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=0.08[Temperature(C)/Load 2 (N)] 0.4 . 
     
     
         19 . The method of  claim 13  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=Y[Load(N)] X , where Y is a constant integer of less than 1 and X value is less than zero. 
     
     
         20 . The method of  claim 13  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=0.4[Load(N)] −0.8 . 
     
     
         21 . The method of  claim 13  wherein the one or more liquid crystals are represented by the formula: 
       
         
           
           
               
               
           
         
       
     
     
         22 . The method of  claim 13  wherein the one or more liquid crystals comprise hexakis(octylthio)benzene. 
     
     
         23 . The method of  claim 13  wherein the lubricating oil further comprises one or more of an antiwear additive, viscosity modifier, antioxidant, detergent, dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         24 . The method of  claim 13  wherein the lubricating oil is a machining or pre-run fluid for smoothing and conforming mated metal surfaces. 
     
     
         25 . A method for improving and maintaining friction and wear control in an engine or other mechanical component lubricated with a lubricating oil, said method comprising:
 (i) providing an engine or other mechanical component having mated metal surfaces;   (ii) conducting a run-in by contacting the mated metal surfaces with a first lubricating oil having a composition comprising at least one lubricating oil base stock; wherein the at least one lubricating oil base stock comprises one or more liquid crystals, wherein the one or more liquid crystals are represented by the formula:
   A—(R1) n  
 
   
       wherein A is a mono-ring or a multi-ring aromatic group, R1 is the same or different and is a substituted or unsubstituted, hydrocarbon group, alkoxy, or alkylthio having from about 2 to about 24 carbon atoms, and n is a value from about 1 to about 12; and wherein the lubricating oil base stock has a kinematic viscosity of about 2 cSt to about 200 cSt at 40° C., as determined according to ASTM D445, and a kinematic viscosity of about 1 cSt to about 25 cSt at 100° C., as determined according to ASTM D445; wherein friction and wear control are improved as compared to friction control and wear control achieved using a lubricating oil containing a lubricating oil base stock other than the lubricating oil base stock comprising one or more liquid crystals;
 (iii) removing the first lubricating oil from the engine or other mechanical component after the run-in; and 
 (iv) contacting the mated metal surfaces with a second lubricating oil containing a lubricating oil base stock other than the lubricating oil base stock comprising one or more liquid crystals; wherein the improved friction control and wear control from conducting the run-in are maintained. 
 
     
     
         26 . The method of  claim 25  wherein, in friction coefficient measurements of the lubricating oil base stock of the first lubricating oil by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction), Verschleiž (wear) test machine (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.25. 
     
     
         27 . The method of  claim 25  wherein, in friction coefficient measurements of the lubricating oil base stock of the first lubricating oil by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction), Verschleiž (wear) test machine (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.20. 
     
     
         28 . The method of  claim 25  wherein, in friction coefficient measurements of the lubricating oil base stock of the first lubricating oil by a reciprocating cylinder-on-disc (RCD) Schwingung (oscillating), Reibung (friction), Verschleiž (wear) test machine (SRV) in accordance with ASTM D5707, the friction coefficient is less than about 0.10. 
     
     
         29 . The method of  claim 25  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=W[Temperature(C)/Load 2 (N)] z , where W and Z are both independently constant integers of less than 1 and greater than zero value. 
     
     
         30 . The method of  claim 25  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=0.08[Temperature(C)/Load 2 (N)] 0.4 . 
     
     
         31 . The method of  claim 25  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=Y[Load(N)] X , where Y is a constant integer of less than 1 and X value is less than zero. 
     
     
         32 . The method of  claim 25  wherein the Friction Coefficient (FC) can be defined by a general formula: FC=0.4[Load(N)] 0.8 . 
     
     
         33 . The method of  claim 25  wherein the one or more liquid crystals are represented by the formula: 
       
         
           
           
               
               
           
         
       
     
     
         34 . The method of  claim 25  wherein the one or more liquid crystals comprise hexakis(octylthio)benzene. 
     
     
         35 . The method of  claim 25  wherein the first and second lubricating oils further comprise one or more of an antiwear additive, viscosity modifier, antioxidant, detergent, dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor or anti-rust additive.