Toyo Ink Mfg. Co., Ltd.

Tdk Electronics Company, Limited

Makio Sugai

Yuichi Kubota

Masaharu Nishimatsu

Kazushi Tanaka

Osamu Shinoura

Ryozo Konno

Yukihiro Isobe

Akira Ohtsuki

Nobumori Kanno

Takashi Mihoya

Radiation-curable, magnetic coating material and magnetic recording

Magnetic recording medium

In a magnetic recording medium made by applying a non-magnetic undercoat and a magnetic top coat on a base, the undercoat comprises a radiation-curable coating material which contains a compound with a molecular weight of not less than 400, having one type of double bond selected from among acrylic, allylic, and maleic double bonds, the undercoat being formed by exposure to radiation. Specifically, the undercoating material contains at least two types of compounds selected from (A) those having a molecular weight of over 5000, preferably over 8000 and having two or more double bonds selected as above, (B) those having a molecular weight of 400 or more but less than 500, preferably in the range of 600 to 3000, and two or more double bonds selected as above, and (C) those having a molecular weight of less than 400 and one or more double bonds selected from among acrylic, allylic, maleic, and styrenic double bonds. At least two types of the compounds are used in a mixing ratio of 0-90 wt % (A), 0-80 wt % (B), and 0-50 wt % wt % (C).

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Tokyo, Japan

Makio Sugai