| 摘要 |
<p>[PROBLEMS] To provide a biodegradable lubricating oil composition which has excellent biodegradability, a high viscosity index, a low pour point, a high flash point, being satisfactory with lubricity, oxidative stability, property of preventing the corrosion of iron and non-ferrous metals, and suitability for use with sealing materials. [MEANS FOR SOLVING THE PROBLEMS] A biodegradable lubricating oil composition comprising (A) a synthetic ester base oil comprising at least 50 mass% hindered ester of an aliphatic monocarboxylic acid with an aliphatic hindered polyol which has one or more quaternary carbon atoms per molecule and in which at least one of the quaternary carbon atoms has one to four methylol groups bonded thereto and (B) ingredients which are (a) 0.1 to 5.0 mass% phenolic antioxidant, (b) 0.01 to 2.0 mass% calcium sulfonate having a low base number, and (c) 0.01 to 1.0 mass% triazole compound, and has the degree of biodegradation of 60 % or higher when examined by the test for the degree of microbial degradation of chemical substances according to the OECD Test Guideline 301C method.</p> |
