Metal Working Fluid

Abstract

The present invention relates to a metal working fluid comprising abase oil having a viscosity index of more than 110 according to ASTM D 2270 and a pour point of less than −40° C. according to ASTM D 97. Preferably the base oil is a Fischer-Tropsch derived oil. Preferably, the base oil has a kinematic viscosity at 100° C. of between 2 and 3 mm 2 /s, according to ASTM D 445. Further, the base oil preferably has a flash point of more than 170° C., preferably more than 175° C., most preferably more than 180° C., according to ASTM D 92.

1 . Metal working fluid comprising at least 80 wt % of a Fischer-Tropsch derived a base oil, the base oil having a viscosity index of more than 110 according to ASTM D 2270 and a pour point of less than −40° C. according to ASTM D 97, wherein the base-oil has a Noack Volatility at 150° C. of less than 2. 
     
     
         2 . Metal working fluid according to  claim 1 , wherein the base oil has a viscosity index of more than 115. 
     
     
         3 . Metal working fluid according to  claim 1  or  2 , wherein the base oil has a pour point of less than −50° C. 
     
     
         4 . Metal working fluid according to one or more of the preceding claims, wherein the base oil has a kinematic viscosity at 100° C. of between 1-4 mm 2 /s. 
     
     
         5 . Metal working fluid according to one or more of the preceding claims, wherein the base oil has a flash point of more than 170° C., according to ASTM D 92. 
     
     
         6 . Metal working fluid according to one or more of the preceding claims, wherein the base oil has a Delta Distillation value (95 wt %-5 wt %) of less than 130° C., preferably less than 100° C., even more preferably less than 95° C., the distillation values being determined according to ASTM D 2888. 
     
     
         7 . Metal working fluid according to one or more of the preceding claims, wherein the base oil has a Delta Distillation value (95 wt-5 wt %) of less than 100° C., the distillation values being determined according to ASTM D 2888. 
     
     
         8 . Metal working fluid according to one or more of the preceding claims, wherein the base oil is obtained by 
       (a) hydrocracking/hydroisomerisating a Fischer-Tropsch product, 
       (b) separating the product of step (a) into at least one or more fuel fractions and the base oil fraction. 
     
     
         9 . Metal working fluid according to  claim 8 , wherein the base oil is obtained by subjecting a fraction boiling above 350° C. as obtained in step (b) to a dewaxing step (c). 
     
     
         10 . Metal working fluid according to one or more of the preceding claims, wherein the metal working fluid comprises one or more additives. 
     
     
         11 . Use of the metal working fluid according to one or more of the preceding claims as a metal working fluid, in particular for high speed machining. 
     
     
         12 . Metal working method using a high speed rotary machine operating at a speed of above 8000 rotations per minute (RPM) wherein the rotary machine is provided with a rotatable hollow shaft through which the metal working fluid according to any one of  claims 1 - 11  flows to a machine tool mounted on the shaft. 
     
     
         13 . Metal working method according to  claim 12 , wherein the metal working method is a high speed grinding operation in which the grinding operation is performed using a grinding stone at a speed of between 50 and 200 m/s. 
     
     
         14 . Metal working method according to any one of  claims 12 - 13 , wherein the metal working fluid is provided to the machine at a pressure of between 20 and 60 bar.