Functional fluids having low brookfield viscosity using high viscosity-index base stocks, base oils and lubricant compositions, and methods for their production and use

Abstract

The present invention relates to functional fluids, especially automatic transmission fluids showing surprising low temperature Brookfield viscosities and methods to produce them.

1 . A method for producing functional fluid containing a Group II or Group III base stock and having a Brookfield Viscosity at −40° C. of about 15,000 cp or less comprising: 
 (I) adding from about 50 vol % to about 20 vol % of at least one first base stock having 
 (a) a kinematic viscosity of 1.5 to about 8.5 mm 2 /sec at 100° C.,  
 (b) a viscosity index of about 120 to about 160,  
 (c) a pour point of about −9° C. to −24° C.,  
 (d) a saturates content of about 92 to about 100 mass % made from natural mineral or synthetic waxy hydrocarbon feedstock which waxy feedstocks have a wax content of at least about 50 wt % and which waxy feedstocks are converted into said base stock by 
 (i) hydrotreating the waxy feedstock with a hydrotreating catalyst under effective hydrotreating conditions such that less than 5 wt % of the feedstock is converted to 343° C. (650° F.) minus products to produce a hydrotreated feedstock whose VI increase is less than 4 greater than the VI of the waxy feedstock;  
 (ii) stripping or distilling the hydrotreated feedstock to separate gaseous product form liquid product;  
 (iii) hydrodewaxing the liquid product with a dewaxing catalyst under catalytically effective hydrodewaxing conditions wherein the dewaxing catalyst contains at least one Group 9 or Group 10 noble metal;  
 (iv) optionally hydrofinishing the product from (iii) with a hydrofinishing catalyst under hydrofinishing conditions;  
 
   (II) from about 50 vol % to 80 vol % of a hydrocracked Group II or Group III or mixture thereof comprising one or more hydrocracked bases stocks having: 
 (a) a kinematic viscosity of about 1.5 to about 8.5 mm 2 /sec at 100° C.,  
 (b) a viscosity index of about 90 or higher,  
 (c) a pour point of about −15° C. or less,  
 (d) a saturates content of about 92 to about 100 mass %  
 said mixture of base stocks having:  
 (a) a kinematic viscosity of about 3 mm 2 /sec to about 6.5 mm 2 /sec at 100° C.,  
 (b) a viscosity index of about 120 to about 150,  
 (c) a pour point of about −15° C. or less; and  
   (III) at least one performance additive; 
 wherein said functional fluid has:  
 (a) a kinematic viscosity of about 4.5 to about 9.5 mm 2 /sec at 100° C.,  
 (b) a viscosity index of about 150 to about 230,  
 (c) a pour point of about −42° C. or less, and  
 (d) a Brookfield viscosity of about 15,000 cP or less at −40° C.  
   
   
   
       2 . The method of  claim 1  wherein said functional fluid has a kinematic viscosity of about 5.5 to about 8.5 mm 2 /sec at 100° C.  
   
   
       3 . The method of  claim 1  wherein said functional fluid has a Brookfield viscosity of about 13,000 cP or less at −40° C.  
   
   
       4 . The method of  claim 1  wherein said functional fluid has a Brookfield viscosity of about 10,000 cP or less at −40° C.  
   
   
       5 . The method of  claim 1  wherein said first base stock incorporated into said functional fluid has a kinematic viscosity of about 2.0 to about 6.0 mm 2 /sec at 100° C.  
   
   
       6 . The method of  claim 1  wherein said first base stock incorporated into said functional fluid has a kinematic viscosity of about 3.0 to about 5.0 mm 2 /sec at 100° C.  
   
   
       7 . The method of  claim 1  wherein said first base stock incorporated into said functional fluid has a viscosity index of about 130 to about 150.  
   
   
       8 . The method of  claim 1  wherein said first base stock incorporated into said functional fluid has a pour point of about −12° C. to −24° C.  
   
   
       9 . The method of  claim 1  wherein said first base stock incorporated into said functional fluid has a saturates content of about 96 to about 100 mass %.  
   
   
       10 . The method of  claim 1  wherein: 
 (I) the at least one first base stock has 
 (a) a kinematic viscosity of 3.0 to about 5.0 mm 2 /sec at 100° C.,  
 (b) a viscosity index of about 130 to about 150,  
 (c) a pour point of about −15° C. to −24° C.,  
 (d) a saturates content of about 96 to about 100 mass %; and  
   (II) the about 50 vol % to 80 vol %, of hydrocracked Group II or Group III base stock or mixture thereof comprising one or more hydrocracked bases stocks has: 
 (a) a kinematic viscosity of about 1.5 to about 6.5 mm 2 /sec at 100° C.,  
 (b) a viscosity index of about 90 or higher,  
 (c) a pour point of about −15° C. or less,  
 (d) a saturates content of about 92 to about 100 mass %  
 wherein said mixture of base stocks has:  
 (a) a kinematic viscosity of about 3.5 mm 2 /sec to about 5.5 mm 2 /sec at 100° C.,  
 (b) a viscosity index of about 120 to about 150,  
 (c) a pour point of about −15° C. or less; and  
 wherein said functional fluid has:  
 (a) a kinematic viscosity of about 5.5 to about 8.5 mm 2 /sec at 100° C.,  
 (b) a viscosity index of about 150 to about 230,  
 (c) a pour point of about −42° C. or less, and  
 (d) a Brookfield viscosity of about 13,000 cP or less at −40° C.  
   
   
   
       11 . The method of  claim 1  wherein the functional fluid is an Automatic Transmission Fluid.  
   
   
       12 . The method of  claim 1  wherein said first base stock is a gas-to-liquid base stock.  
   
   
       13 . The method of  claim 10  wherein the functional fluid is an Automatic Transmission Fluid.  
   
   
       14 . The method of  claim 10  wherein said first base stock is a gas-to-liquid base stock.  
   
   
       15 . The method of  claim 11  wherein said first base stock is a gas-to-liquid base stock.  
   
   
       16 . The method of  claim 1 ,  11 ,  12 ,  13 ,  14  or  15 , wherein the hydrodewaxing of the liquid product with a dewaxing catalyst uses as the dewaxing catalyst 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 alumina containing at least one Group 9 or Group 10 noble metal.  
   
   
       17 . The method of  claim 1 ,  11 ,  12 ,  13 ,  14  or  15  wherein the hydrofinishing step employs a mesoporous hydrofinishing catalyst from the M41-S family.  
   
   
       18 . The method of  claim 1 ,  11 ,  12 ,  13 ,  14  or  15  wherein the hydrodewaxing catalyst is ZSM-48 containing at least one Group 9 or Group 10 noble metal and the hydrofinishing catalyst is MCM-41.