Abstract: The lubricating oil composition of the present invention contains a base oil, a 2,6-di-tert-butylphenol (A), and at least one compound (B) selected from a benzotriazole compound and a sorbitan compound.

Abstract: A lubricating oil composition contains: a base oil with a kinematic viscosity at 40 degrees C. in a range from 1 mm2/s to 200 mm2/s, a viscosity index of 80 or more and a sulfur content of less than 0.03 mass %; a component (A) being a polyacrylate compound with a mass average molecular weight in a range from 10,000 to 100,000; and a component (B) being at least one of phosphorus compounds represented by a formula (1) below. A content of the component (B) is in a range from 0.05 mass % to 2.0 mass % of a total amount of the composition, and a viscosity index of the composition is 160 or more.

Abstract: A management method of a lubricating oil of the invention is a method of managing a lubricating oil by determining a degradation degree of the lubricating oil containing an antioxidant, specifically, according to determination methods a and b below. The determination method a includes: measuring an infrared ray absorption spectrum of the lubricating oil using a Fourier transform infrared spectrometer; and calculating a total content of the antioxidant and an altered substance having an antioxidant function to determine a deterioration degree of the lubricating oil from the obtained content. The determination method b includes: filtrating the lubricating oil with a filter; subsequently measuring a color difference of substances captured by the filter using a colorimeter, or measuring a color difference of the lubricating oil using the colorimeter; and determining a degradation degree of the lubricating oil and a mixture degree of foreign substances based on the obtained color difference.

Abstract: Provided is a lubricating oil composition containing a refined paraffinic mineral oil (A) and an alkylbenzene (B) having a flash point of 160° C. or higher, and having a flash point of 250° C. or higher. The lubricating oil composition has a high flash point of 250° C. or higher and has an excellent long lifetime to such an extent that the lubricating oil composition can maintain excellent oxidation stability even in long-term use in high-temperature environments.

Abstract: The lubricating oil composition of the present invention contains a base oil, a 2,6-di-tert-butylphenol (A), and at least one compound (B) selected from a benzotriazole compound and a sorbitan compound.

Abstract: A management method of a lubricating oil of the invention is a method of managing a lubricating oil by determining a degradation degree of the lubricating oil containing an antioxidant, specifically, according to determination methods a and b below. The determination method a includes: measuring an infrared ray absorption spectrum of the lubricating oil using a Fourier transform infrared spectrometer; and calculating a total content of the antioxidant and an altered substance having an antioxidant function to determine a deterioration degree of the lubricating oil from the obtained content. The determination method b includes: filtrating the lubricating oil with a filter; subsequently measuring a color difference of substances captured by the filter using a colorimeter, or measuring a color difference of the lubricating oil using the colorimeter; and determining a degradation degree of the lubricating oil and a mixture degree of foreign substances based on the obtained color difference.

Abstract: A lubricating oil composition contains: a base oil with a kinematic viscosity at 40 degrees C. in a range from 1 mm2/s to 200 mm2/s, a viscosity index of 80 or more and a sulfur content of less than 0.03 mass %; a component (A) being a polyacrylate compound with a mass average molecular weight in a range from 10,000 to 100,000; and a component (B) being at least one of phosphorus compounds represented by a formula (1) below. A content of the component (B) is in a range from 0.05 mass % to 2.0 mass % of a total amount of the composition, and a viscosity index of the composition is 160 or more.

Abstract: The present invention provides a lubricating oil composition exhibiting more excellent flame retardancy and biodegradability. The biodegradable lubricating oil composition of the invention has flame retardancy and contains (1) a base oil containing a plant-derived oil in an amount of 60 mass % or more, and a polyol ester in an amount of 40 mass % or less, and (2) a polymethacrylate having a mass average molecular weight of 20,000 to 300,000 in an amount of 0.1 to 5 mass %.

Abstract: A process for producing a polycyanoaryl ether powder which comprises reacting a dihalogenobenzonitrile, a dihydric phenol and an alkali metal salt in the presence of a polymerization solvent, and distilling the solvent, while pulverizing the reaction mixture under agitation. The process produces a polycyanoaryl ether powder having excellent physical properties and is useful as a material for electronic appliances, electric appliances and parts of machines.