To provide a method for purifying a lubricant, by which the lubricant having excellent lubrication characteristics and high stability against its employment for a long period and capable of being used for magnetic recording media is obtained.
This method for purifying the lubricant containing a perfluoropolyether structure-having compound by a supercritical extraction method is characterized by bringing the lubricant into contact with an extraction solvent comprising supercritical carbon dioxide under prescribed conditions in a pressure vessel to remove ionic impurities and low polar terminal group-having perfluoropolyether compounds contained in the perfluoropolyether lubricant from the lubricant. The lubricant purified by the method. A magnetic recording medium using the lubricant.
SHIRAI SHINJI
ISHIKAWA MASAYUKI
Kazuo Abe
Denichi Hashimoto
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