Fuji Electric Co., Ltd.

Youich Tei

Katsunori Suzuki

Syoji Sakaguchi

The gas components in thermoplastic norbornene resin pellets are suppressed below certain levels by drying the resin under vacuum or under the ordinary pressure and under vacuum. A substrate for magnetic recording media is manufactured by injection-molding the resin dried by the method according to the invention. The magnetic recording medium, employing the substrate manufactured according to the invention, includes at least a magnetic layer, a protection layer on the magnetic layer and a liquid lubricant layer on the protection layer. The magnetic recording medium is manufactured by forming these layers, one after another, on the substrate according to the invention.

Substrate for magnetic recording media using dried thermoplastic norbornene resin and magnetic recording media using substrate

A thermoplastic norbornene resin is purified by using a cleaning liquid to eliminate organic impurities, ionic impurities, metallic impurities, and particles of the resin. The cleaning liquid is selected from 2-propanol and a mixed solvent of 2-propanol and water. A substrate for a magnetic recording medium of the invention is fabricated by injection-molding the thermoplastic norbornene resin purified by this method. A magnetic recording medium of the invention includes such a substrate, and a magnetic layer, a protective layer, and a liquid lubricant layer sequentially formed on the substrate. A method for manufacturing such a magnetic recording medium is also provided.

Method for purifying a thermoplastic norbornene resin, a substrate using such a resin, and a magnetic recording medium using such a substrate

A thermoplastic norbornene resin is purified by using a cleaning liquid to eliminate organic impurities, ionic impurities, metallic impurities, and particles of the resin. The cleaning liquid is selected from 2-propanol and a mixed solvent of 2-propanol and water. A substrate for a magnetic recording medium of the invention by fabricated by injection-molding the thermoplastic norbornene resin purified by this method. A magnetic recording medium of the invention includes such a substrate, and a magnetic layer, a protective layer, and a liquid lubricant layer sequentially formed on the substrate. A method for manufacturing such a magnetic recording medium is also provided.

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Nagano, Japan

Youich Tei