Method for improving the corrosion inhibiting properties of lubricant compositions

Abstract

Lubricating oils of improved initial and long term metal corrosion inhibiting properties comprises a base stock containing one or more hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s), GTL base stock(s) and/or base oil(s), or mixtures thereof, preferably GTL base stock(s) and/or base oil(s), boiling in the lubricating oil boiling range and an additive amount of an anti-corrosion additive.

1 . A method for enhancing the corrosion resistance of lubricating oil formulations comprising base oil additized with one or more anti-corrosion additive(s), said method comprising employing as the base oil for the lubricating oil formulation a base oil comprising one or more hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s), GTL base stock(s) and/or base oil(s), or mixtures thereof, boiling in the lube oil boiling range.  
   
   
       2 . A method for enhancing the metal corrosion resistance of lubricating oil formulations comprising base oil additized with one or more anti-corrosion additive(s) and one or more corrosive anti-wear additives, said method comprising employing as the base oil for the lubricating oil formulation a base oil comprising one or more hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s), GTL base stock(s) and/or base oil(s), or mixtures thereof, boiling in the lube oil boiling range.  
   
   
       3 . A method for reducing the rate of corrosion in an apparatus lubricated using a lubricating oil formulation containing one or more anti-corrosion additive(s) during use by lubricating the apparatus using a lubricating oil containing one or more anti-corrosion additive(s) and a base oil comprising one or more hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s), GTL base stock(s) and/or base oil(s), or mixtures thereof, boiling in the lube oil boiling range.  
   
   
       4 . A method for reducing the rate of corrosion in an apparatus lubricated using a lubricating oil formulation containing one or more anti-corrosion additive(s) and one or more corrosive anti-wear additive(s) by lubricating the apparatus using a lubricating oil containing the one or more anti-corrosion additive(s), the one or more corrosive anti-wear additive(s) and a base oil comprising one or more hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s), GTL base stock(s) and/or base oil(s), or mixtures thereof, boiling in the lube oil boiling range.  
   
   
       5 . A method for enhancing the corrosion resistance of lubricating oil formulations comprising mineral oil base oil and/or polyalpha olefin base oil additized with one or more anti-corrosion additive(s), and, optionally, one or more corrosive anti-wear additive(s) by replacing all or part of the mineral oil base oil and/or polyalpha olefin base oil with one or more hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s), GTL base stock(s) and/or base oil(s) or mixtures thereof, boiling in the lube oil boiling range.  
   
   
       6 . The method of claims  1 ,  2 ,  3 ,  4  or  5  wherein the one or more hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s), GTL base stock(s) and/or base oil(s), or mixtures thereof, comprise 5 to 100% by weight of the base oil.  
   
   
       7 . The method of claims  1 ,  2 ,  3 ,  4 , or  5  wherein the one or more anti-corrosion additive(s) is/are present in an amount of about 0.001 to 5 wt % active ingredient, relative to the weight of the total lubricant composition.  
   
   
       8 . The method of claims  2 ,  4  or  5  wherein the one or more corrosive anti-wear additive(s) and the one or more anti-corrosion additive(s) is/are present in a weight ratio of about 45:1 to 1:1.  
   
   
       9 . The method of  claim 7  wherein the one or more anti-corrosion additive(s) is/are present in an amount of about 0.01 to 1.5 wt % active ingredient relative to the weight of the total lubricant composition.  
   
   
       10 . The method of  claim 8  wherein the corrosive anti-wear additive(s) and the anti-corrosion additive(s) are present in a weight ratio of about 30:1 to 1:1.  
   
   
       11 . The method of  claim 10  wherein the corrosive anti-wear additive and the anti-corrosion additive(s) are present in a weight ratio of about 30:1 to 3:1.  
   
   
       12 . The method of  claim 11  wherein the corrosive anti-wear additive(s) and the anti-corrosion additive(s) are present in a weight ratio of about 15:1 to 3:1.  
   
   
       13 . An aviation piston engine oil comprising 
 (i) a base oil comprising: 
 (a) at least 10 wt % based on the total weight of the base oil of one or more hydrodewaxate or hydroisomerate base stock(s) and/or base stock(s), GTL base stock(s) and/or base oil(s), or mixtures thereof, having a kinematic viscosity at 100° C. in the range of about 3 to 25 mm 2 /s;  
 (b) about 20 to 90 wt % based on the total weight of the base oil of one or more mineral oils having a kinematic viscosity at 100° C. in the range from about 4 to 40 mm 2 /s;  
 (c) about zero to 30 wt % based on the total weight of the base oil of polyalpha olefin having a kinematic viscosity at 100° C. in the range from about 4 to 40 mm 2 /s;  
   (ii) an effective amount of additive comprising one or more of viscosity index improver, anti-oxidant, anti-foam agent, dye, ashless dispersant, anti-wear additive, extreme pressure additive;    (iii) about 0.001 to about 5 w% active ingredient anti-corrosion additive.    
   
   
       14 . The aviation piston engine oil of  claim 14  wherein the additive (ii) comprises at least 2 wt % ashless dispersant.  
   
   
       15 . The method of claims  1 ,  2 ,  3 ,  4  or  5  wherein the base oil is hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s) or mixture thereof.  
   
   
       16 . The method of claims  1 ,  2 ,  3 ,  4  or  5  wherein the base oil is a GTL base stock(s) and/or base oil(s).  
   
   
       17 . The aviation piston engine oil of  claim 13  or  14  wherein the one or more hydrodewaxate or hydroisomerate base stock(s) and/or base oil(s), GTL base stock(s) and/or base oil(s), or mixtures thereof, is a mixture of at least two of said base stock of (i)(a) wherein one of the base stock(s) has a KV of about 10 to 25 mm 2 /s.  
   
   
       18 . The aviation piston engine oil of  claim 17  wherein the mixture of at least two of the said base stock(s) and/or base oil(s) of (i)(a), one of the base stock(s) and/or base oil(s) has a KV of about 12 to 25 mm 2 /s.  
   
   
       19 . The aviation piston engine oil of  claim 13  or  14  wherein the base stock and/or base oil (i)(a) constitutes at least 25 wt % of the total base oil.  
   
   
       20 . The aviation piston engine oil of claims  13  or  14  wherein the base stock and/or base oil (i)(a) constitutes at least 30 wt % of the total base oil.  
   
   
       21 . The aviation piston engine oil of claims  13  or  14  wherein the base stock and/or base oil (i)(a) constitutes at least 40 wt % of the total base oil.