Fuji Photo Film Company, Limited

National Patent Development Corporation

Xerox Corporation

The Nisshin Oil Mills, Ltd.

Toagosei Chemical Industry, Co., Ltd.

Nobuo Tsuji

Masaaki Fujiyama

Yasuyuki Yamada

Tsutomu Okita

Yoshito Mukaida

Shinji Sakaguchi

Nobutaka Yamaguchi

Goro Akashi

Takushi Miyazako

Nobuyuki Yamamoto

Yuzo Higaki

Norio Nasu

Toshihisa Okamura

Hiroshi Hashimoto

Yasuo Tamai

Takahito Miyoshi

Akihiro Matsufuji

Katsumi Ryoke

Yasuo Mukunoki

Yasuo Nishikawa

Toshimitu Okutu

Takeshi Mikami

Sumitaka Tatsuta

Yasutoshi Okuzawa

Teruo Nakagawa

Koichi Yamauchi

Yasuyuki Tanaka

Keisuke Shiba

Noriyuki Inoue

Masakazu Yoneyama

Seiiti Kubodera

Eiichi Tadokoro

Kiyoshi Nakazyo

Akio Miyamoto

Akira Kasuga

Chiaki Mizuno

Tadao Sugimoto

Satoru Honjo

Sadao Ishige

Kyoichi Naruo

Kenichi Masuyama

Shigeo Komine

Kazuhiko Morita

Jun Arakawa

Hajime Kato

Hideomi Watanabe

Kimitaka Kameoka

Hajime Miyatsuka

Nobuo Yamamoto

Ikutaro Horie

Motohiko Tsubota

Tadashi Ishiguro

Takahisa Ogasawara

Tohru Sueyoshi

Shinichi Funabashi

Shinichi Imai

Hiromi Nakahara

Keiji Tanaka

Masatoshi Kiyama

June Yamaguchi

Kenji Naito

Keitaro Ohe

Isao Yamamoto

Akiyoshi Hashimoto

Kiyoshi Murase

Yasuo Inoue

Kenji Yokoo

Takenori Omichi

Teruo Yamaguchi

Masaaki Fujiyana

Takahisa Ogasawara, Deceased

Nobutaka Yamaguichi

Kenzo Hasunuma

Hajime Miyazuka

Junn Yamaguchi

Nagao Kameji

Maskazu Yoneyama

A magnetic recording medium comprising a non-magnetic support having provided thereon a magnetic layer containing ferromagnetic particles and a binder, wherein the magnetic layer contains at least one lubricating agent selected from the group consisting of a salt of a sulfonic acid and a salt of sulfuric acid ester.

Magnetic recording medium

A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a magnetic layer containing CrO.sub.2 fine particles and a binder, wherein the binder comprises polycarbonate polyurethane in an amount of from about 30 to about 90 wt %, based on the total weight of said binder.

A magnetic recording medium is described, comprising a non-magnetic support base having positioned thereon a magnetic layer and optionally a non-magnetic layer, wherein at least one layer of the magnetic and non-magnetic layers contains an oxyfatty acid ester. This recording medium has superior surface properties and thus superior running properties, and can be satisfactorily used in tape decks.

Magnetic recording media

A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a ferromagnetic thin metal film, wherein a layer consisting essentially of a boric acid ester compound is provided on the ferromagnetic thin metal film.

A magnetic recording medium comprised of a support base having a magnetic recording provided thereon is disclosed. The recording layer is comprised of ferromagnetic particles dispersed in a binder. The binder includes (1) a vinyl chloride-vinyl alkanoate type copolymer containing --CO.sub.2 H group of 5.times.10.sup.-5 to 1.7.times.10.sup.-3 equivalent per g of the polymer, (2) urethane acrylate having a molecular weight in the range of from 20,000 to 300,000, and (3) a compound having at least two (meth)acryloyl groups in the molecule and having a molecular weight of 600 or less. The magnetic recording layer is irradiated with electron beams in order to harden the binder. The resulting medium has excellent electromagnetic properties and the magnetic coating composition prepared for making the magnetic recording layer has excellent stability during storage.

A magnetic recording medium comprising a non-magnetic support having thereon an electron-beam radiation-cured magnetic recording layer, said magnetic layer comprising a ferromagnetic oxide and a binder comprising

A magnetic recording medium comprising a support having coated thereon a magnetic layer is disclosed. The magnetic layer contains, as a binder, a composition cured with electron beam comprising (a) at least one of vinyl chloride-vinyl acetate type resins containing 5.times.10.sup.-5 to 1.7.times.10.sup.-3 equivalents of a carboxyl group per gram of the polymer and introcellulose resins, (b) a urethane resin and (c) at least one compound selected from the group consisting of aromatic or alicyclic compounds containing at least two vinyl linkages in the molecule and acryloyl-modified polyisocyanate compounds. The magnetic recording medium has excellent electromagnetic properties and durability.

This invention provide a magnetic recording medium with well-balanced excellent properties as to video head abrasion, still life, video S/N and drop out, which comprises a non-magnetic support and a magnetic recording layer containing a ferromagnetic powder, a binder and (A) at least one inorganic compound powder selected from the group consisting of Cr.sub.2 O.sub.3, SiC and mixtures thereof and (B) at least one inorganic compound powder selected from the group consisting of Al.sub.2 O.sub.3, TiO.sub.2, SiO.sub.2, ZnO and mixtures thereof.

There is provided a magnetic recording material produced by coating on a support a magnetic coating composition which contains as main components a magnetic powder and a binder, the binder comprising an urethane acrylate synthesized using a polyester polyol having a particular structure, and by irradiating the resulting magnetic coat with electron beams to harden it. The polyester polyol contains polyhydric alcohol component, 50 mole % or more of which is a dihydric alcohol selected from the class (A) described below, and/or polybasic acid component, 50 mole % or more of which is a dibasic acid selected from the class (B) described below. The urethane acrylate is synthesized under such a condition that it may have two or more of (meth)acryloyl groups per molecule. Thus, improvements in electromagnetic properties and in durability are attained.

Magnetic recording material

A magnetic recording medium is described, comprising a support and a magnetic layer disposed thereon, said magnetic layer containing as its binder component a combination of at least one member of each of the following groups of compounds (1) to (3) that has been exposed to electron beams:

There is provided a magnetic recording material which comprises a support and a magnetic layer coated thereon. The magnetic layer contains as its binder, a combination of at least one vinyl chloride-vinyl acetate-based copolymer characterized by its --CO.sub.2 H content or cellulose dinitrate, at least one urethane acrylate having a particular chemical structure, and at least one low molecular weight compound having two or more acryloyl or methacryloyl groups. The magnetic layer is hardened by beam irradiation. Thus, marked increase in dispersibility of ferromagnetic powders, improvement in electromagnetic transformation characteristics and sharp increase in durability are attained.

A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a magnetic layer comprising ferromagnetic particles dispersed in a binder, said ferromagnetic particles having a BET specific surface area of 25 m.sup.2 /g or more, said binder comprising a modified polyurethane resin containing 0.1 meq/g or more of functional groups selected from carboxyl groups, hydroxyl groups, sulfonic acid groups, and epoxy groups, and containing at least three functional groups per molecule of the resin.

A magnetic recording medium is described, comprising a non-magnetic support base having positioned thereon a magnetic layer and optionally a non-magnetic layer, wherein at least one layer of the magnetic and non-magnetic layers contains an ester derived from pentaerythritol and/or its condensate and a fatty acid and/or a resin acid. This recording medium has superior surface properties and can be satisfactorily used in tape decks.

A magnetic recording medium is disclosed. The medium is comprised of a support and a magnetic layer provided thereon wherein an oxyfatty acid is incorporated in the magnetic layer or in the surface of a support or layer coming into contact with the magnetic layer. The coefficients of friction of the magnetic layer with parts of a magnetic recording/reproducing deck are low and thus the magnetic recording medium has superior lubricity.

Magnetic recording media with oxyfatty acid lubricant

A magnetic recording medium which comprises a non-magnetic support having thereon a magnetic recording layer containing a ferromagnetic fine powder and a binder as main components is disclosed. The magnetic recording layer containing as the binder (1) a vinyl chloride-vinyl acetate-maleic acid copolymer which has a mean polymerization degree of about 300 to about 400 and a maleic acid fraction of about 0.6 to about 1.5 wt %, (2) a polyurethane resin which has a number average molecular weight of 40,000 to 100,000 and is prepared from (i) a mixture of polyneopentyladipate having a mean molecular weight of 500 to 2,500 and polybutyleneadipate having a mean molecular weight of 500 to 2,500 with a mixing ratio of the former to the latter of from 2/8 to 9/1 by weight and (ii) diphenylmethane diisocyanate, and optionally (3) a low molecular weight polyisocyanate compound.

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Kanagawa, Japan

Nobuo Tsuji