Patent ID: 8889608

Claim:
A lubricatiiu oil base oil, consisting essentially of diesters represented by the following formulae (1), (2), and (3), wherein these three type diesters have same C12 linear alkyl main chain with different branched alkyl both end groups, and wherein a total number of branched carbon atoms involved in methyl groups and ethyl groups present as branched structures in the diesters represented by the formulae (1), (2), and (3) (hereinafter, referred to as “branched carbon atom ratio”) is 11% or less with respect to a number of all carbon atoms as the whole diesters, and a molar ratio of the diesters represented by the formulae (1), (2), and (3) falls within a range of (1):(2):(3)=45 to 85:10 to 45:1 to 15: where C 3 H 7 and C 4 H 9 represent n-C 3 H 7 and n-C 4 H 9 , respectively.