Method for improving oxidation and deposit resistance of lubricating oils

Abstract

Provided is a method for improving oxidation resistance and deposit resistance of a lubricating oil for use in lubricating a mechanical component. The method includes the step of providing the lubricating oil to the mechanical component and measuring the improved oxidation and deposit resistance. The lubricating oil includes a lubricating oil base stock at from 0 to 80 wt %, at least one branched isoparaffin having a mole % of epsilon carbon as measured by C13 NMR of less than or equal to 10% at from 20 to 80 wt %, at least one viscosity modifier at from 5 to 20 wt %, and one or more other lubricating oil additives. The oxidation resistance in the CEC L-109 oxidation resistance test is improved to greater than 310 hours to achieve a 100% viscosity increase and the deposit resistance in the TEOST 33C is improve to total deposits of less than 45 mg as compared to oxidation resistance and deposit resistance achieved using a lubricating oil not containing the at least one branched isoparaffin.

1 . A lubricating oil comprising:
 a lubricating oil base stock at from 0 to 80 wt % of the lubricating oil, at least one branched isoparaffin having a mole % of epsilon carbon as measured by  13 C NMR of less than or equal to 10% at from 20 to 80 wt % of the lubricating oil, at least one viscosity modifier at from 5 to 20 wt % of the lubricating oil, and wherein the remainder of the lubricating oil includes one or more other lubricating oil additives; and   wherein oxidation resistance is improved (CEC L-109 oxidation resistance to a 100% viscosity increase greater than 310 hours) and deposit resistance is improved (TEOST 33C total deposits less than 45 mg) for the lubricating oil as compared to oxidation resistance and deposit resistance achieved using a lubricating oil not containing the at least one branched isoparaffin having a mole % of epsilon carbon as measured by  13 C NMR of less than or equal to 10%.   
     
     
         2 . The oil of  claim 1 , wherein the lubricating oil base stock is selected from the from the group consisting of a Group I base stock, a Group II base stock, a Group III base stock, a Group IV base stock, a Group V base stock and combinations thereof. 
       The oil of  claim 2 , wherein the Group III base stock is a gas to liquids (GTL) base stock and the Group IV base stock is a polyalphaolefin (PAO) base stock. 
     
     
         3 . The oil of  claim 2 , wherein the Group V base stock is an ester based Group V base stock selected from the group consisting of a C11/C13/C15/C17 Estolide, a C8/C10 TMP ester, a C7/C9/C11/C13/C15 TMP ester, a C6/C7/C9 TMP ester, a C15/C17 diester, a C6/C7/C9 TMP ester, a C4/C5/C6/C7/C8/C9 TMP ester, C16 mixed mono and di alkylated naphthalene, and combinations thereof. 
     
     
         4 . The oil of  claim 3 , wherein the ester based Group V base stock comprises a monoester, a di-ester, a polyol ester, a complex ester or mixtures thereof derived from a renewable biological material. 
     
     
         5 . The oil of  claim 4 , wherein the renewable biological material is derived from coconut oil, palm oil, rapeseed oil, soy oil, vegetable oil, or sunflower oil. 
     
     
         6 . The oil of  claim 2 , wherein the lubricating oil base stock is a blend of Group III, Group IV and Group V base stocks. 
     
     
         7 . The oil of  claim 1 , wherein the at least one branched isoparaffin is selected from the group consisting of squalane, isosqualane, pristine, tetracosane, isoparaffins represented by the formulas 
       
         
           
           
               
               
           
         
         and combinations thereof. 
       
     
     
         8 . The oil of  claim 7 , wherein the at least one branched isoparaffin is squalane having a kinematic viscosity at 100 deg. C. ranging from 3.9 to 4.3 cSt. 
     
     
         9 . The oil of  claim 1 , wherein the at least one viscosity modifier comprises linear or star-shaped polymers and copolymers of methacrylate, butadiene, olefins, alkylated styrenes or combinations thereof. 
     
     
         10 . The oil of  claim 1 , wherein the at least one viscosity modifier is selected from the group consisting of polyisobutylene, polymethacrylate, polyisoprene, copolymers of ethylene and propylene, hydrogenated block copolymers of styrene and isoprene, styrene-butadiene based polymers, star polyisoprene polymers, star polyisoprene-styrene copolymers and combinations thereof. 
     
     
         11 . The oil of  claim 1 , wherein the one or more other lubricating oil additives are selected from the group consisting of an anti-wear additive, viscosity index improver, antioxidant, detergent, dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, anti-rust additive, and friction modifier. 
     
     
         12 . The oil of  claim 1 , wherein the lubricating oil has a kinematic viscosity at 100 deg. C. ranging from 4.5 to 12.5 cSt. 
     
     
         13 . The oil of  claim 1 , wherein lubricating oil 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. 
     
     
         14 . The oil of  claim 1 , wherein the lubricating oil is a passenger vehicle engine oil (PVEO) or a commercial vehicle engine oil (CVEO). 
     
     
         15 . The oil of  claim 1 , wherein the oxidation resistance or deposit resistance is measured at an oxygen partial pressure of less than 90 psig. 
     
     
         16 . The oil of  claim 1 , wherein the at least one branched isoparaffin has a mole % of alpha carbon as measured by  13 C NMR of less than 3.8%. 
     
     
         17 . The oil of  claim 1 , wherein the at least one branched isoparaffin has a mole % of T/P methyl as measured by  13 C NMR of greater than 2%. 
     
     
         18 . The oil of  claim 1 , wherein the at least one branched isoparaffin has a mole % of P-methyl as measured by  13 C NMR of greater than 5%.