Patent ID: 8648021

Claim:
A hydrocarbon-based lubricating base oil wherein a urea adduct value is not greater than 4% by mass, a viscosity index is 100 or higher, an average of carbon atoms number is 23-31 as determined by gas chromatography distillation, a value obtained by dividing an integral value of a peak in 30 ppm by an integral value of total peaks in the range from 0 ppm to 50 ppm for the 13 C-NMR spectrum is 0.1-0.2, and a product of a value obtained by dividing an integral value of peaks attributed to tertiary carbon atoms by an integral value of total peaks in the range of from 0 ppm to 50 ppm for the 13 C-NMR spectrum, and the average of carbon atoms number, is 1.8-2.5.