| 摘要 |
PROBLEM TO BE SOLVED: To produce a phenyl sulfide-based antioxidant that contains a thiobisphenol having a specific chemical structure, does not contain chlorine and is useful as an antioxidant without causing excessive corrosion of copper when added to a lubricating oil of low phosphorus content for cars and trucks. SOLUTION: This phenyl sulfide-based antioxidant contains a thiobisphenol, selected from compounds of formulas I and II (R and R1 are H or an alkyl; (x) is 1-8)m which are obtained by a reaction of one or preferably two or more hindered phenols of formula III (R2 is H or an alkyl), such as 2-t-butylphenol, which do not contain chlorine, with a mixture of sulfur source, preferably element sulfur, and an accelerator composed of a hydroxide of an alkali metal in a polar solvent, preferably 2-propanol. The obtained sulfide based-antioxidant is preferably used in a concentration of 0.5-0.2wt.% when added to a lubricant composition, etc. |
