LUBRICATING OIL COMPOSITION

摘要

PROBLEM TO BE SOLVED: To obtain a lubricating oil composition having excellent antioxidant properties and sludge formation preventive properties and does not deteriorate in performances even when used for a long time under high-temperature conditions by mixing a lube base oil with a specified alkyphenol in a specified ratio. SOLUTION: This composition is obtained by mixing 100 pts.wt. lube base oil with 0.1-5 pts.wt., desirably 0.2-3 pts.wt. 2-t-butyl-4-alkyloxymethyl-6- alkylphenol represented by the formula (wherein R<1> is a 1-4C alkyl; and R<2> is a 1-24C alkyl or alkenyl). The lube base oil is desirably at least one member selected among mineral oils (e.g. hydrocracked paraffinic mineral oils) having a kinematic viscosity of 5-200mm<2> /s and a total aromatic content of 15mass% or below, polymers of a 2-16C olefin of hydrogenation products thereof and having a number-avearge molecular weight of 250-4,000 (e.g. hydrogenated 1- decene oligomer) and alkylbenzenes each having 1-4 1-40C alkyls and the total number of carbon atoms of the alkyls of 6-40.