Sony Corporation

Toshiharu Uchimi

Hirofumi Kondo

Yukihiro Koshika

Kenichi Sato

Hidetoshi Honda

Jota Ito

Taketoshi Sato

Yasumi Sato

Takashi Chiba

A magnetic recording medium having a thin magnetic metal film formed by vapor deposition under an atmosphere of an introduced oxygen gas. The thickness of the surface oxide film having the degree of oxidation of 50% or higher is maintained so as to be not higher than 5% of the total film thickness of the thin magnetic metal film. The magnetic recording medium is affected to a lesser extent by the surface oxide layer such that it is superior in magnetic properties, such as coercivity, and in electromagnetic properties.

Magnetic recording medium

Novel perfluoropolyether derivatives are described which are obtained from perfluoropolyethers having a carboxyl group at one or both ends and monoamines or diamines. The derivative is useful as a lubricant owing to its significantly improved lubricity. The lubricity is shown under severe high or low temperature and humidity conditions over a long term. The derivative is especially useful as a lubricant for magnetic recording mediums of the coating and metal thin film types.

Perfluoropolyether derivatives, and lubricants and magnetic recording

A lubricant contains ester compound made of perfluoropolyether and long chain alkyl carboxylic acid or alcohol. The perfluoropolyether has hydroxyl or carboxyl group at its end. The ester compound is admixed with long chain alkyl amine of from 0.01 to 100 in mole ratio. The long chain alkyl may be partially fluorined or perfluoro alkyl. At least one of phosphoric ester, phosphorous ester and long chain carboxylate ester can be further admixed. A magnetic recording medium can be coated by the lubricant.

Lubricant and magnetic recording medium therewith

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Miyagi, Japan

Toshiharu Uchimi