Low viscosity lubricating oils with improved oxidative stability and traction performance

Abstract

Provided is lubricating oil composition including from 10 to 90 wt % of a base stock comprising a C28-C32 hydrocarbon fraction (“dimers”) and optionally a C42-C48 hydrocarbon fraction (“trimers”) produced by oligomerization of a linear C14 mono-olefin, a linear C16 mono-olefin, or a mixture thereof, in the presence of a Lewis acid catalyst, and the remainder of the composition including one or more lubricating oil additives. The lubricating oil composition provides an oxidative stability of greater than 100 hours (time to 200% KV@40 deg. C. increase) and a mini traction machine (MTM) average traction coefficient at 100 deg. C. of less than 0.0081.

1 . A lubricating oil composition comprising
 from 10 to 90 wt % of a base stock comprising a C28-C32 hydrocarbon fraction (“dimers”) and optionally a C42-C48 hydrocarbon fraction (“trimers”) produced by oligomerization of a linear C14 mono-olefin, a linear C16 mono-olefin, or a mixture thereof, in the presence of a Lewis acid catalyst, and   the remainder of the composition comprising one or more lubricating oil additives, wherein the lubricating oil composition provides an oxidative stability of greater than 100 hours (time to 200% KV@40 deg. C. increase) and a mini traction machine (MTM) average traction coefficient at 100 deg. C. of less than 0.0081.   
     
     
         2 . The composition of  claim 1 , wherein the base stock exhibits a mole percentage of epsilon-carbons as determined by  13 C NMR of no less than 20 mol %, based on the total moles of the carbon atoms therein. 
     
     
         3 . The composition of  claim 1 , wherein the dimers are at a concentration in the range from 80 to 100 wt %, and the trimers are at a concentration in the range from 0 to 20 wt %, based on the total weight of the base stock. 
     
     
         4 . The composition of  claim 1 , wherein the total concentration of the dimers and the trimers combined is at least 95 wt %, based on the total weight of the base stock. 
     
     
         5 . The composition of  claim 1 , wherein the molecules of the dimers comprise, on average, no more than 2.0 branches attached to the carbon backbones therein. 
     
     
         6 . The composition of  claim 1 , wherein the base stock has a pour point as determined pursuant to ASTM D5950 of in a range from −45 to −10° C. 
     
     
         7 . The composition of  claim 1 , wherein the base stock has a cold-crank-simulator viscosity as determined pursuant to ASTM D5293 (“CCSV”) at −35° C. of at least 500 mPa·s. 
     
     
         8 . The composition of  claim 1 , wherein the base stock has a kinematic viscosity at 100° C. as determined pursuant to ASTM D445 (“KV100”) in the range from 3.3 to 4.6 cSt. 
     
     
         9 . The composition of  claim 1 , wherein the base stock has a CCSV at −35° C. of CCSVmPa·s;
 when blended with a PAO reference base stock made from one or more linear alpha-olefin monomer(s) comprising 8 to 12 carbon atoms having a KV100 of 4.0 to 4.2 cSt, a pour point of no higher than −50° C., a CCSV at −35° C. of CCSV(PAO4) mPa·s, where 1200≤CCSV(PAO4)≤1500, to form a first mixture oil comprising 10 wt % of the base stock based on the total weight of the first mixture oil, a second mixture oil comprising 20 wt % of the base stock based on the second mixture oil, and a third mixture oil comprising 30 wt % of the base stock based on the total weight of the base stock, at least one of the following is met: 
 (i) the first mixture oil exhibits a lower CCSV at −35° C. than the PAO reference base stock; 
 (ii) the second mixture oil exhibits a lower CCSV at −35° C. than the PAO reference base stock; and 
 (iii) the third mixture oil exhibits a lower CCSV at −35° C. than the PAO reference base stock. 
 
     
     
         10 . The composition of  claim 9 , wherein the base stock meets at least one of the following:
 (i) the first mixture oil exhibits a CCSV at −35° C. at least 50 mPa·s lower than that of the PAO reference base stock;   (ii) the second mixture oil exhibits a CCSV at −35° C. at least 50 mPa·s lower than that of the PAO reference base stock; and   (iii) the third mixture oil exhibits a CCSV at −35° C. at least 50 mPa·s lower than that of the PAO reference base stock.   
     
     
         11 . The composition of  claim 9 , wherein the base stock exhibits a CCSV at −35° C. lower than that of the PAO reference base stock. 
     
     
         12 . The composition of  claim 1 , wherein the one or more lubricating oil additives are selected from the group consisting of a detergent, dispersant, viscosity index improver, viscosity modifier, metal passivator, antioxidant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, anti-rust additive, friction modifier, extreme pressure agent and combinations thereof. 
     
     
         13 . The composition of  claim 12 , wherein the one or more lubricating oil additives comprise from 1 to 30 wt. % of the lubricating oil composition. 
     
     
         14 . The composition of  claim 1  further including a cobase stock at from 1 to 30 wt. % of the lubricating oil composition, wherein the cobase stock is selected from the group consisting of a Group I base stock, a Group II base stock, a Group III base stock, a conventional Group IV base stock, a Group V base stock and combinations thereof. 
     
     
         15 . The composition of  claim 1 , wherein the lubricating oil composition has a kinematic viscosity at 25° C. as determined pursuant to ASTM D445 (“KV25”) at least 0.5% lower than a comparable lubricating oil composition not including the C28-C32 hydrocarbon fraction (“dimers”). 
     
     
         16 . The composition of  claim 1 , wherein the lubricating oil composition has a cold-crank-simulator viscosity as determined pursuant to ASTM D5293 (“CCSV”) at −35° C. at least 5% lower than a comparable lubricating oil composition not including the C28-C32 hydrocarbon fraction (“dimers”). 
     
     
         17 . The composition of  claim 1 , wherein the lubricating oil composition is used as a passenger vehicle engine oil (PVEO), commercial vehicle engine oil (CVEO) or a natural gas engine oil. 
     
     
         18 . The composition of  claim 1 , wherein the lubricating oil composition is an SAE viscosity grade selected from the group consisting of 0W-30, 5W-30, 0W-20, 5W-20, 0W-16, 5W-16, 0W-12, 5W-12, 0W-8, and 5W-8. 
     
     
         19 . A lubricating oil composition comprising:
 from 10 to 90 wt % of a base stock comprising a C28 to C32 hydrocarbon first fraction at a concentration in the range from 80 to 100 wt %, and a C42 to C48 second fraction at a concentration in the range from 0 to 20 wt %, based on the total weight of the base stock;   wherein the base stock has a kinematic viscosity at 100° C. as determined pursuant to ASTM D445 (“KV100”) in the range from 3.3 to 4.6 cSt; a pour point as determined pursuant to ASTM D5950 in the range from −45 to −10° C.; and   a cold-crank-simulator viscosity as determined pursuant to ASTM D5293 (“CCSV”) at −35° C. of at least 500 mPa·s; and   the remainder of the composition comprising one or more lubricating oil additives, wherein the lubricating oil composition provides an oxidative stability of greater than 100 hours (time to 200% KV@40 deg. C. increase) and a mini traction machine (MTM) average traction coefficient at 100 deg. C. of less than 0.0081.   
     
     
         20 . The composition of  claim 19 , further including a cobase stock at from 1 to 30 wt. % of the lubricating oil composition, wherein the cobase stock is selected from the group consisting of a Group I base stock, a Group II base stock, a Group III base stock, a conventional Group IV base stock, a Group V base stock and combinations thereof. 
     
     
         21 . The composition of  claim 19  further including a Group II, III, or IV base stock as a second base stock, wherein the first base stock has a CCSV at −35° C. of CCSV(1), the second base stock has a CCSV at −35° C. of CCSV(2), and the binary mixture of the first base stock and the second base stock in the oil composition absent any component other than the first base stock and the second base stock has a CCSV at −35° C. of CCSV(3), such that:
   CCSV(2)>CCSV(3). 
 
     
     
         22 . The composition of  claim 21 , wherein:
   (CCSV(2)−CCSV(3))/CCSV(2)≥0.05.
   
     
     
         23 . The composition of  claim 22 , wherein:
 the second base stock comprises a Group II or Group III base stock, and
   (CCSV(2)−CCSV(3))/CCSV(2)≥0.10.
 
   
     
     
         24 . The composition of  23 , wherein:
   CCSV(1)≥CCSV(2).
   
     
     
         25 . The composition of  claim 19 , wherein the one or more lubricating oil additives are selected from the group consisting of a detergent, dispersant, viscosity index improver, viscosity modifier, metal passivator, antioxidant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, anti-rust additive, friction modifier, extreme pressure agent and combinations thereof. 
     
     
         26 . The composition of  claim 25 , wherein the one or more lubricating oil additives comprise from 1 to 30 wt. % of the lubricating oil composition. 
     
     
         27 . The composition of  claim 19 , wherein the lubricating oil composition has a kinematic viscosity at 25° C. as determined pursuant to ASTM D445 (“KV25”) at least 0.5% lower than a comparable lubricating oil composition not including the C28-C32 hydrocarbon fraction (“dimers”). 
     
     
         28 . The composition of  claim 19 , wherein the lubricating oil composition has a cold-crank-simulator viscosity as determined pursuant to ASTM D5293 (“CCSV”) at −35° C. at least 5% lower than a comparable lubricating oil composition not including the C28-C32 hydrocarbon fraction (“dimers”). 
     
     
         29 . The composition of  claim 19 , wherein the lubricating oil composition is used as a passenger vehicle engine oil (PVEO), commercial vehicle engine oil (CVEO) or a natural gas engine oil. 
     
     
         30 . The composition of  claim 19 , wherein the lubricating oil composition is an SAE viscosity grade selected from the group consisting of 0W-30, 5W-30, 0W-20, 5W-20, 0W-16, 5W-16, 0W-12, 5W-12, 0W-8, and 5W-8.