Base oil blends having unexpectedly low brookfield dynamic viscosity and lubricant compositions therefrom

Abstract

A base oil having an unexpectedly low dynamic viscosity as measured by ASTM D5133 test method comprises a blend of about 65 to 97.5 wt % of a paraffinic oil having a VI of 130 or greater, a Kv@100° C. of about 3.8 cSt or greater and a pour point of −15° C. or less and an ester of lubricating viscosity of from about 35 to about 2.5 wt %. The base oil is further characterized as free of added viscosity modifiers.

1 . A base stock or base oil comprising: 
 (a) from about 65 to about 97.5 wt %, based on the weight of the base stock or base oil of a paraffinic oil having a VI of 130 or greater, a Kv at 100° C. of about 3.8 cSt or greater and a pour point of −15° C. or less; and    (b) from about 2.5 to about 35 wt %, based on the weight of the base stock or base oil of an ester of lubricating viscosity, wherein the base stock or base oil has good low temperature performance as evidenced by their dynamic viscosity as measured by ASTM D5133 test method.    
     
     
         2 . The base stock or base oil of  claim 1  further characterized as free of added viscosity modifiers.  
     
     
         3 . The base stock or base oils of  claim 2  wherein the paraffinic oil is produced by a process which comprises: 
 (a) hydrotreating a feedstock having a wax content of about 60 wt % based on feedstock with a hydrotreating catalyst under effective hydrotreating conditions such that less than 5 wt % of the feedstock is converted to 650° F. (343° C.) minus products to produce a hydrotreated feedstock whose VI increase is less than 4 and greater than the VI of the feedstock;    (b) stripping the hydrotreated feedstock to separate gaseous product from liquid product;    (c) hydrodewaxing the liquid product with a dewaxing catalyst which is at least one of ZSM-48, ZSM-57, ZSM-23, ZSM-22, ZSM-35, ferrierite, ECR-42, ITQ-13, MCM-71, MCM-68, beta, fluorided alumina, silica-alumina or fluorided silica-alumina, under effective hydrodewaxing conditions wherein the dewaxing catalyst contains at least one Group 9 or Group 10 metal.    
     
     
         4 . A functional fluid composition comprising the base stock or base oil of claims  1  or  3  and at least one additive other than a viscosity modifier.  
     
     
         5 . A method of making a functional fluid having a high VI and good low temperature performance as evidenced by dynamic viscosity as measured by ASTM D5133 test method comprising: 
 blending (i) from about 65 to about 97.5 wt %, based on the weight of the fluid, of a paraffinic oil prepared by: 
 (a) hydrotreating a feedstock having a wax content of about 60 wt % based on feedstock with a hydrotreating catalyst under effective hydrotreating conditions such that less than 5 wt % of the feedstock is converted to 650° F. (343° C.) minus products to produce a hydrotreated feedstock whose VI increase is less than 4 and greater than the VI of the feedstock;  
 (b) stripping the hydrotreated feedstock to separate gaseous product from liquid product;  
 (c) hydrodewaxing the liquid product with a dewaxing catalyst which is at least one of ZSM-48, ZSM-57, ZSM-23, ZSM-22, ZSM-35, ferrierite, ECR-42, ITQ-13, MCM-71, MCM-68, beta, fluorided alumina, silica-alumina or fluorided silica-alumina, under effective hydrodewaxing conditions wherein the dewaxing catalyst contains at least one Group 9 or Group 10 metal,  
   with (ii) from about 2.5 to about 35 wt %, based on the weight of the fluid, of an ester of lubricating viscosity.    
     
     
         6 . The method of  claim 5  including incorporating at least one additive other than a viscosity modifier.