Lubricant composition with low deposition tendency

Abstract

Lubricant base oil blends and finished lubricating compositions having low deposition tendency are provided. The base oil blends consist essentially of about 20 wt % to about 80 wt %, based on the total weight of the blend, of an F-T Group III base oil having less than 5 wt % cycloparaffins, the balance of the blend being a Group III base oil having at least 35 wt % cycloparaffins. The finished lubricating compositions comprise a major amount of the base oil blend of the invention and at least one engine oil additive.

1 . A lubricating base oil blend consisting essentially of from about 20 wt % to about 80 wt %, based on the total weight of the blend, of an F-T Group III base oil having less than 5 wt % cycloparaffins, the balance being a Group III base oil having at least 35 wt % cycloparaffins. 
   
   
       2 . The blend of  claim 1  wherein the F-T Group III base oil comprises 30 wt % to 80 wt % of the blend. 
   
   
       3 . The blend of  claim 2  wherein the F-T Group III base oil comprises 50 wt % to 80 wt % of the blend. 
   
   
       4 . The blend of  claim 3  wherein the Group III base oil has from 40 wt % to 50 wt % of cycloparaffins. 
   
   
       5 . The blend of  claim 4  wherein the Group III base oil has from about 44 wt % to about 50 wt % of cycloparaffins. 
   
   
       6 . A lubricating oil composition comprising:
 a major amount of a base oil blend consisting essentially of about 20 wt % to about 80 wt %, based on the total weight of the blend, of an F-T Group III base oil having less than 5 wt % cycloparaffins, the balance of the blend being a Group III base oil having at least 35 wt % cycloparaffins, and   at least one engine oil additive selected from dispersants, detergents, antiwear agents, VI improvers, antioxidants, defoamants, friction modifiers and rust inhibitors.   
   
   
       7 . The composition of  claim 6  wherein the F-T Group III base oil comprises 30 wt % to 80 wt % of the blend. 
   
   
       8 . The composition of  claim 7  wherein the F-T Group III base oil comprises 50 wt % to 80 wt % of the blend. 
   
   
       9 . The composition of  claim 8  wherein the Group III base oil has from 35 wt % to 50 wt % of cycloparaffins. 
   
   
       10 . The composition of  claim 9  wherein the Group III base oil has from about 40 wt % to about 50 wt % of cycloparaffins. 
   
   
       11 . A method for improving the deposit control as measured by test MTH-4 (ASTM D7097) of a fully formulated engine oil comprising an F-T Group III base oil having less than 5 wt % cycloparaffins, the method comprising blending the F-T Group III base oil with a sufficient amount of a Group III base oil having at least 35 wt % cycloparaffins to provide the blend with from about 20 wt % to about 80 wt %, based on the total weight of the blend, of the F-T Group III oil. 
   
   
       12 . The method of  claim 11  wherein the Group III base oil has from about 40 wt % to about 50 wt % of cycloparaffins. 
   
   
       13 . The method of  claim 12  wherein the amount of Group III oil is sufficient to provide a blend with from 30 wt % to 80 wt % of the F-T Group III base oil. 
   
   
       14 . Use of the base oil blend of any one of  claims 1  to  5  as the base oil in a fully formulated engine oil.