Idemitsu Kosan Company, Limited

Jitsuo Shinoda

Shinji Aoki

Hirotaka Yamasaki

Toshiharu Takizawa

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.

Lubricating oil composition

A lubricating oil composition contains: a base oil with a kinematic viscosity at 40 degrees C. in a range from 1 mm/s to 200 mm/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. 

Lubricant oil composition

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.

Method for managing lubricant oil, and method for predicting life of lubricant oil

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.

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Ichihara, Japan

Jitsuo Shinoda