Lubricant Compositions and Methods Comprising Dispersant and Detergent

Abstract

A lubricant composition may comprise at least one phosphorus- and boron-containing dispersant, at least one boron-containing dispersant, and at least one detergent. Such composition may be useful in power transmissions to provide improved anti-shudder performance and/or improved friction durability.

1 . A power transmitting fluid, comprising: 
 (a) a major amount of a base oil; and    (b) an additive composition comprising 
 (i) at least one first phosphorus- and boron-containing dispersant in an amount of about 2.0 wt % or more in the fluid;  
 (ii) at least one second boron-containing dispersant, free of phosphorus; and  
 (iii) at least one metal-containing detergent;  
   wherein the fluid has a steel-on-steel coefficient of friction μ (Mid Point)  of greater than or equal to about 0.13 and    wherein the fluid has a steel-on-paper coefficient of friction μ 20 /μ 100  of less than or equal to about 1.0.    
   
   
       2 . The fluid of  claim 1 , wherein the total amount of boron and phosphorus in the fluid is at least about 500 ppm.  
   
   
       3 . The fluid of  claim 1 , wherein the first dispersant comprises a phosphorylated and boronated polyisobutylene succinimide, bis-succinimide, or mixture thereof.  
   
   
       4 . The fluid of  claim 3 , wherein the polyisobutylene has a weight average molecular weight of about 900.  
   
   
       5 . The fluid of  claim 1 , wherein the second dispersant comprises a boronated polyisobutylene succinimide, bis-succinimide, or mixture thereof.  
   
   
       6 . The fluid of  claim 5 , wherein the polyisobutylene has a weight average molecular weight of about 900 to about 1300.  
   
   
       7 . The fluid of  claim 1 , wherein the detergent comprises an overbased detergent.  
   
   
       8 . The fluid of  claim 1 , wherein the detergent comprises a sulfonate or a phenate.  
   
   
       9 . The fluid of  claim 1 , wherein the detergent comprises one or more of calcium sulfonate, magnesium sulfonate, sodium sulfonate, calcium phenate, and zinc phenate.  
   
   
       10 . The fluid of  claim 1 , wherein the detergent comprises a calcium sulfonate having about 1.5 wt % to about 20 wt % calcium.  
   
   
       11 . The fluid of  claim 9 , wherein the calcium sulfonate comprises a TBN of about 250 mg KOH/g to about 400 mg KOH/g.  
   
   
       12 . The power transmitting fluid of  claim 1 , wherein the detergent comprises a calcium phenate having about 2.5 wt % to about 8.5 wt % calcium.  
   
   
       13 . The power transmitting fluid of  claim 1 , wherein the detergent comprise a calcium phenate having a TBN of about 50 mg KOH/g to about 300 mg KOH/g.  
   
   
       14 . The power transmitting fluid of  claim 1 , further comprising one or more of an antioxidant, an extreme pressure additive, a corrosion inhibitor, an antiwear additive, a metal deactivator, an antifoam agent, a viscosity index improver, a pour point depressant, an air entrainment additive, a metallic detergent, and a seal swell agent.  
   
   
       15 . The power transmitting fluid of  claim 1 , wherein the additive composition is suitable for use in a transmission employing one or more of a slipping torque converter, a lock-up torque converter, a starting clutch, and one or more shifting clutches.  
   
   
       16 . The power transmitting fluid of  claim 1 , wherein the additive composition is suitable for use in one or more of a belt-type, a chain-type, and a disk-type continuously variable transmission.  
   
   
       17 . A continuously variable transmission fluid comprising 
 (a) a major amount of a base oil; and    (b) an additive composition comprising 
 (i) at least one first phosphorus- and boron-containing dispersant in an amount of about 2.0 wt % or more in the fluid;  
 (ii) at least one second boron-containing dispersant, free of phosphorus; and  
 (iii) at least one metal-containing detergent;  
   wherein the fluid has a steel-on-steel coefficient of friction μ (Mid Point)  of greater than or equal to about 0.13 and    wherein the fluid has a steel-on-paper coefficient of friction μ 20 /μ 100  of less than or equal to about 1.0.    
   
   
       18 . The fluid of  claim 17 , wherein the total amount of boron and phosphorus in the fluid is at least about 500 ppm.  
   
   
       19 . A method for maintaining high steel-on-steel friction and minimizing steel-on-paper friction comprising: 
 lubricating a transmission with a lubricating composition comprising: 
 (a) a major amount of a base oil; and  
 (b) an additive composition comprising 
 (i) at least one first phosphorus- and boron-containing dispersant in an amount of about 2.0 wt % or more in the fluid;  
 (ii) at least one second boron-containing dispersant, free of phosphorus; and  
 (iii) at least one metal-containing detergent;  
 
   wherein the fluid has a steel-on-steel coefficient of friction μ (Mid Point)  of greater than or equal to about 0.13 and    wherein the fluid has a steel-on-paper coefficient of friction μ 20 /μ 100  of less than or equal to about 1.0.    
   
   
       20 . The fluid of  claim 19 , wherein the total amount of boron and phosphorus in the fluid is at least about 500 ppm.  
   
   
       21 . A method of increasing steel-on-steel fiction comprising: 
 lubricating a transmission having steel-on-steel friction with a lubricating composition comprising a major amount of a base oil and an additive composition comprising:    (a) at least one first phosphorus- and boron-containing dispersant in an amount of about 2.0 wt % or more in the fluid;    (b) at least one second boron-containing dispersant, free of phosphorus; and    (c) at least one metal-containing detergent,    wherein the total amount of boron and phosphorus in the fluid is at least about 500 ppm.    
   
   
       22 . A method of improving anti-shudder comprising: 
 lubricating a transmission having shudder with a lubricating composition comprising a major amount of a base oil and an additive composition comprising:    (a) at least one first phosphorus- and boron-containing dispersant in an amount of about 2.0 wt % or more in the fluid;    (b) at least one second boron-containing dispersant, free of phosphorus; and    (c) at least one metal-containing detergent,    wherein the total amount of boron and phosphorus in the fluid is at least about 500 ppm.    
   
   
       23 . A method of stabilizing steel-on-paper friction comprising: 
 lubricating a transmission having steel-on-paper friction with a lubricating composition comprising a major amount of a base oil and an additive composition comprising:    (a) at least one first phosphorus- and boron-containing dispersant in an amount of about 2.0 wt % or more in the fluid;    (b) at least one second boron-containing dispersant, free of phosphorus; and    (c) at least one metal-containing detergent,    wherein the total amount of boron and phosphorus in the fluid is at least about 500 ppm.