Lubricant base oil and method for producing same

Abstract

A lubricant base oil that is a hydrocarbon oil having a kinematic viscosity at 100° C. of 2.0 to 9 mm 2 /s, a viscosity index of 130 or more, a freezing point of −30 to −5° C., and an SBV viscosity at −20° C. of 1,000 to 60,000 mPa·s, in which the freezing point of the lubricant base oil is higher by 10° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea.

1 . A lubricant base oil that is a hydrocarbon oil having a kinematic viscosity at 100° C. of 2.0 to 9 mm 2 /s, a viscosity index of 130 or more, a freezing point of −30 to −5° C., and an SBV viscosity at −20° C. of 1,000 to 60,000 mPa·s, wherein
 the freezing point of the lubricant base oil is higher by 10° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea. 
 
     
     
         2 . The lubricant base oil according to  claim 1 , which is a hydrocarbon oil having a kinematic viscosity at 100° C. of 3.0 to 5.0 mm 2 /s, a viscosity index of 145 or more, a freezing point of −20 to −5° C., and an SBV viscosity at −20° C. of 3,000 to 60,000 mPa·s, wherein
 the freezing point of the lubricant base oil is higher by 10° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea. 
 
     
     
         3 . The lubricant base oil according to  claim 1 , which is a hydrocarbon oil having a kinematic viscosity at 100° C. of 5 to 9 mm 2 /s, a viscosity index of 155 or more, a freezing point of −15 to −5° C., and an SBV viscosity at −20° C. of 3,000 to 30,000 mPa·s, wherein
 the freezing point of the lubricant base oil is higher by 10° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea. 
 
     
     
         4 . The lubricant base oil according to  claim 1 , which is a hydrocarbon oil having a kinematic viscosity at 100° C. of 2.0 to 3.0 mm 2 /s, a viscosity index of 130 or more, a freezing point of −30 to −10° C., and an SBV viscosity at −30° C. of 1,000 to 30,000 mPa·s, wherein
 the freezing point of the lubricant base oil is higher by 15° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea. 
 
     
     
         5 . A method for producing a lubricant base oil, the method comprising:
 a first step of fractionating, from a hydrocarbon oil containing a base oil fraction and a heavy fraction that is heavier than the base oil fraction, the base oil fraction and the heavy fraction;   a second step of returning a cracked oil obtained by hydrocracking the heavy fraction fractionated in the first step, to the first step;   a third step of obtaining a dewaxed oil by performing hydroisomerization dewaxing of the base oil fraction;   a fourth step of obtaining a refined oil by refining the dewaxed oil; and   a fifth step of obtaining a lubricant base oil that is a hydrocarbon oil having a kinematic viscosity at 100° C. of 2.0 to 9 mm 2 /s, a viscosity index of 130 or more, a freezing point of −30 to −5° C., and an SBV viscosity at −20° C. of 1,000 to 60,000 mPa·s, by fractionation of the refined oil, wherein   the third step is a step of performing hydroisomerization dewaxing of the base oil fraction such that the freezing point of the lubricant base oil obtained in the fifth step is higher by 10° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea.   
     
     
         6 . The method according to  claim 5 , wherein
 the fifth step is a step of obtaining a lubricant base oil that is a hydrocarbon oil having a kinematic viscosity at 100° C. of 3.0 to 5.0 mm 2 /s, a viscosity index of 145 or more, a freezing point of −20 to −5° C., and an SBV viscosity at −20° C. of 3,000 to 60,000 mPa·s, by fractionation of the refined oil, and   the third step is a step of performing hydroisomerization dewaxing of the base oil fraction such that the freezing point of the lubricant base oil obtained in the fifth step is higher by 10° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea.   
     
     
         7 . The method according to  claim 5 , wherein
 the fifth step is a step of obtaining a lubricant base oil that is a hydrocarbon oil having a kinematic viscosity at 100° C. of 5 to 9 mm 2 /s, a viscosity index of 155 or more, a freezing point of −15 to −5° C., and an SBV viscosity at −20° C. of 3,000 to 30,000 mPa·s, by fractionation of the refined oil.   
     
     
         8 . The method according to  claim 5 , wherein
 the fifth step is a step of obtaining a lubricant base oil that is a hydrocarbon oil having a kinematic viscosity at 100° C. of 2.0 to 3.0 mm 2 /s, a viscosity index of 130 or more, a freezing point of −20 to −5° C., and an SBV viscosity at −30° C. of 1,000 to 30,000 mPa·s, by fractionation of the refined oil, and   the third step is a step of performing hydroisomerization dewaxing of the base oil fraction such that the freezing point of the lubricant base oil obtained in the fifth step is higher by 15° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea.   
     
     
         9 . The method according to  claim 5 , wherein the third step is a step of performing hydroisomerization dewaxing of the base oil fraction in the presence of a hydroisomerization catalyst containing at least one crystalline solid acidic substance selected from the group consisting of ZSM-22-type zeolite, ZSM-23-type zeolite, SSZ-32-type zeolite, and ZSM-48-type zeolite, and platinum and/or palladium as an active metal. 
     
     
         10 . The method according to  claim 5 , wherein the hydrocarbon oil in the first step is obtained by using GTL wax obtained by a Fischer-Tropsch synthesis or slack wax obtained by solvent dewaxing, as a raw material.