Fuji Photo Film Company, Limited

Other

Japan Synthetic Rubber Co., Ltd.

Toagosei Chemical Industry, Co., Ltd.

Fuji Photo Film, Inc.

Fuji Photo Co., Ltd.

Tsutomu Okita

Hiroshi Hashimoto

Yasuo Nishikawa

Kyoichi Naruo

Masaki Satake

Hideomi Watanabe

Yoshito Mukaida

Nobuo Tsuji

Masashi Aonuma

Toshio Ishida

Yuichiro Murayama

Noburo Hibino

Jun Nakagawa

Nobuyuki Yamamoto

Yasuyuki Yamada

Masatoshi Takahashi

Katsumi Ryoke

Mikihiko Kato

Toshio Kawamata

Kazuko Hanai

Masahiro Niinomi

Kenji Yanagihara

Mituo Kimura

Teruo Nakagawa

Kazuo Hasumi

Kazunobu Katoh

Kiyomi Ejiri

Goro Akashi

Tadashi Yasunaga

Shigeo Komine

Kazuyuki Usuki

Hiroaki Araki

Akihiro Hashimoto

Kazuhiko Morita

Yasutoshi Okuzawa

Mikio Ohno

Koh Kamada

Takao Ohya

Fumihiro Tokunaga

Yuuichirou Murayama

Akiyoshi Hashimoto

Masami Satou

Hiroshi Ogawa

Masaaki Fujiyama

Nobuo Suzuki

Tatsuji Kitamoto

Takahito Miyoshi

Akihiro Matsufuji

Yasuo Mukunoki

Nobutaka Yamaguchi

Takashi Yoneyama

Satoru Hayakawa

Akira Kasuga

Yasushi Endo

Masatoshi Sugiyama

Hiroyuki Kato

Fusao Yamanaka

Akira Ushimaru

Yutaka Kakuishi

Hiroyuki Tamaki

Hajime Miyatsuka

Hideaki Kosha

Kiyotaka Fukino

Sugihiko Tada

Hideo Kawaguchi

Takahisa Ogasawara

Hiroshi Sawaguchi

Kunihiko Honda

Hiromi Nakahara

Nobuo Aoki

Kiyoshi Murase

Kiritani Masataka

Yuji Andou

Takahisa Ogasawara, Deceased

Yoshihisa Masaki

Kingo Kobayashi

The present invention provides a magnetic recording medium having high dispersion property, good running durability and good preservation property, and it comprises at least one magnetic layer having ferromagnetic powder dispersed by a binder placed on a non-magnetic support member, whereby a polyurethane resin or a polyurethane urea resin consisting of 5 mol % or less of a long chain diol having weight average molecular weight of 800 to 5,000, a short chain diol having weight average molecular weight of 50 to 500 and/or a short chain diamine and an organic diisocyanate is contained as the binder, said long chain diol has one polar group selected from &mdash;COOM, &mdash;SO M, &mdash;OSO M, &mdash;OPO(OM) , or &mdash;PO(OM) (where M represents a hydrogen atom, an alkali metal ion, or an ammonium ion) in the molecule, and the polar group is contained in the polyurethane by 1 to 5 mol %.

Magnetic recording medium

Radiation-setting composition containing (meth)acrylic copolymers containing acid groups

The present invention provides a magnetic recording medium having high durability and excellent electromagnetic transfer characteristics and having a lower coating layer, which contains a binder and has high dispersion property and durability. The magnetic recording medium comprises a lower coating layer where non-magnetic powder or ferromagnetic power is dispersed in a binder and an upper magnetic layer where ferromagnetic powder is dispersed in a binder, said two layers being placed on a non-magnetic support member, whereby the binder of the lower coating layer comprises polyurethane resin, which is a reaction product using diol and organic diisocyanate as major materials, the polyurethane resin contains short-chain diol having cyclic structure by 17 to 40 weight %, and the polyurethane resin contains long-chain diol, containing ether groups by 1.0 to 5.0 mmol/g to the entire polyurethane resin, by 10 to 50 weight %.

Magnetic recording medium having a lower layer containing a specified

The invention relates to a binder which improves the dispersibility of ferromagnetic powders and makes it possible to achieve a magnetic recording medium excellent in operation durability and storability, and a magnetic recording medium using such a binder. The invention provides a magnetic recording medium including a non-magnetic support substrate and a magnetic layer formed on said support substrate, said magnetic layer comprising a dispersion of ferromagnetic fine powders in a binder, wherein said binder comprises a polyurethane resin that is a reaction product obtained by using a polyol and an organic diisocyanate as main starting materials, said polyurethane resin containing as components of said polyol 15 to 40% by weight of a short-chain diol component having a cyclic structure, and 10 to 50% by weight of a long-chain polyether polyol component, and further including a polar group-containing long-chain polyol component having a molecular weight of 500 to 5,000.

In a binder for a magnetic recording medium for forming a magnetic layer with ferromagnetic powder dispersed therein being arranged on a non-magnetic support member, whereby said binder consists of a polyurethane resin, which is a reaction product of diol and organic diisocyanate as principal materials, said polyurethane resin contains a short-chain diol having cyclic structure by 17 to 40 weight %, and said polyurethane resin contains a long-chain diol comprising 1.0 to 5.0 mmol/g of ether group to total urethane resin by 10 to 50 weight %. According to a binder for a magnetic recording medium and a magnetic recording medium using said binder of the present invention, good dispersion property, high running durability and preservation property can be obtained.

Magnetic recording medium comprising ferromagnetic powder and a

A magnetic recording medium is described, which comprises a nonmagnetic support having provided thereon a lower layer comprising nonmagnetic or ferromagnetic particles and a binder resin, and an upper layer provided on the lower layer comprising ferromagnetic metal particles and a binder resin, wherein at least said upper layer contains as a lubricant a compound represented by the following formula (1) in an amount of 1% by weight or more based on the amount of the ferromagnetic metal particles contained in the upper layer:

A magnetic recording medium having a ferromagnetic metal thin film on at least one surface of a non-magnetic support. The magnetic recording medium has a surface layer containing at least either one of fluorine compounds represented by the following formulae (1) and (2):

Magnetic recording medium having a carbon protective layer and a

A magnetic recording medium, comprising a magnetic layer having ferromagnetic metallic thin film at least on one side of a non-magnetic support, whereby a layer is formed on the magnetic layer, said layer contains at least one type of fluorine compounds having at least two perfluoroalkyl groups given by the following general formula (1) or (2) and one or more polar groups selected from --OH, --COOM, --SO.sub.3 M, --OSO.sub.3 M, --PO.sub.3 M.sub.2 or --OPO.sub.3 M.sub.2 (M representing hydrogen atom, alkali metal or ammonium):

A magnetic recording medium comprising a non-magnetic support having thereon a magnetic layer comprising ferromagnetic powder and a binder, the ferromagnetic powder comprising a ferromagnetic metal powder comprising Fe and having a crystal size of from 120 to 250 .ANG. and a Co content of from 5 to 40 atm %, and the binder comprises a polyurethane comprising a diol component and a polyisocyanate component, the diol component comprising a polyetherpolyol and a polyesterpolyol.

Magnetic recording medium having a magnetic layer comprising a specified

A magnetic recording medium having a ferromagnetic metal thin film formed over at least one surface of a non-magnetic support, wherein the improvement has a lubricant layer consisting essentially of at least one of unsaturated bond-containing fluoroalkyl carboxylic acid esters which are represented by the following formulae (1) to (3):

Magnetic recording medium having a cobalt thin film magnetic layer,

A magnetic recording medium is described, which comprises a nonmagnetic support having on at least one side thereof a lower layer and an upper layer, in which the upper layer is a magnetic layer mainly comprising ferromagnetic particles and a binder resin, and the lower layer is adjacent to the magnetic layer and is either a magnetic layer mainly comprising ferromagnetic particles and a binder resin or a nonmagnetic layer mainly comprising nonmagnetic particles and a binder resin, wherein the upper layer has a thickness of from 0.05 to less than 1.0 .mu.m the lower layer has a thickness of from 1 to 5 .mu.m and contains unsaturated alkyl carbonate having from 17 to 45 total carbon atoms represented by the following formula in an amount of from 1.8 to 100% by weight based on the amount of the binder resin: ##STR1## wherein R.sub.1 and R.sub.2 are the same or different and each represents a chain hydrocarbon group having from 8 to 22 carbon atoms, provided that at least one of R.sub.1 and R.sub.2 contains one or more unsaturated bonds; and 60 to 100% by weight of the ferromagnetic particles and nonmagnetic particles contained in the lower layer, in the case where the lower layer is a magnetic layer, has a specific surface area of from 1 to 150 m.sup.2 /g; or 60 to 100% by weight of the nonmagnetic particles contained in the lower layer, in the case where the lower layer is a nonmagnetic layer, has a specific surface area of from 1 to 150 m.sup.2 /g.

Magnetic recording medium comprising a magnetic layer and a sub layer

A binder for a magnetic recording medium comprising a polyurethane which is a reaction product obtained from a polyol and a polyisocyanate as principal raw materials. The polyol is an aliphatic polyol with a molecular weight of not lower than 500. The binder has high dispersibility and provides excellent running durability and shelf stability. Also disclosed is a magnetic recording medium having at least one magnetic or non-magnetic layer containing the above-described binder on at least one surface of a non-magnetic support.

Magnetic recording medium having a magnetic layer containing

A magnetic recording medium having a magnetic layer on a non-magnetic support, whereby an organic fluorine compound given by the following general formulae (1) or (2) is formed on said magnetic layer: ##STR1## where Rf.sup.1, Rf.sup.2 and Rf.sup.3 each represents a fluoroalkyl group, Y.sup.1, Y.sup.2 and Y.sup.3 each represents --O--, --OCO--, --COO, --NHCO--, or --CONH--and may be the same or different;

Magnetic recording medium comprising a magnetic metallic thin film and a

The magnetic recording medium of the present invention comprises a ferromagnetic metallic thin film formed on a non-magnetic support, whereby a protective layer is formed on the ferromagnetic metallic thin film, said protective layer contains at least one type of thiouracil cyclic compounds having hydrocarbon group and at least one type of fluorine compounds having hydrocarbon group, or at least one type of tetrazaindene cyclic compounds and at least one type of fluorine compounds having hydrocarbon group, and no rusting occurs even when it is repeatedly run.

Magnetic recording medium having a protective layer containing a

A binder for a magnetic recording medium which contains a polyvinyl alkylal resin modified by a sultone to introduce thereinto an atom group containing a polar group. Also disclosed is a magnetic recording medium that uses the above-described binder in a magnetic layer, a non-magnetic layer, a protective layer, an undercoat layer, etc. The binder and the magnetic recording medium are superior in dispersibility and exhibit high magnetic coating strength.

Magnetic recording medium having a polyvinyl alkyl binder resin

Growing community of inventors

Kanagawa, Japan

Tsutomu Okita