Fuji Photo Film Company, Limited

Fuji Photo Film, Inc.

Masaki Satake

Tsutomu Okita

Hiroshi Hashimoto

Yuichiro Murayama

Toshio Ishida

Tadashi Yasunaga

Takashi Naoi

Hideki Tomiyama

Hideomi Watanabe

Shuzo Suga

Kazunobu Katoh

Hisashi Okada

Minoru Sakai

Hisashi Okamura

Shigeki Yokoyama

Tomokazu Yasuda

Katsuhiko Meguro

Sumito Yamada

Senzo Sasaoka

Kazuyuki Usuki

Nobuaki Miyasaka

Ikutaro Horie

Hiroshi Kawasaki

Jiro Yamaguchi

Takashi Fujioka

Yuuichirou Murayama

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

The present invention provides a magnetic recording medium having good electromagnetic transfer characteristics and high running durability, and it comprises a lower layer and a magnetic layer, said lower layer having at least one of magnetic powder or non-magnetic inorganic powder and a binder (A) dispersed therein and being placed on a non-magnetic support member, at least one layer of said magnetic layers having ferromagnetic powder and a binder (B) dispersed therein and being deposited on said lower layer, whereby said magnetic recording medium comprises polyurethane resins (1) and (2), said polyurethane resin (1) is contained as said binder (B) and comprises a short-chain diol having a cyclic structure and weight average molecular weight of 200 to 500 in an amount of 15 to 50 weight %, a polyol having an ether group of 1 to 6 mmol/g and weight average molecular weight of 500 to 5000 in an amount of 10 to 50 weight % in polyurethane, and an organic diisocyanate, and said polyurethane resin (2) is contained as said binder (A) and comprises a short-chain diol having cyclic structure and weight average molecular weight of 200 to 500 in an amount of 0 to 15 weight %, a polyol having an ether group of 6 to 14 mmol/g and weight average molecular weight of 500 to 5000 in an amount of 50 to 90 weight %, and an organic diisocyanate.

The present invention provides a magnetic recording medium, which has high dispersion property, high breaking extension and excellent running durability. The magnetic recording medium comprises a magnetic layer having at least one layer of ferromagnetic powder and a binder, said magnetic layer being placed on a non-magnetic support member, whereby said binder contains at least a polyurethane resin (A) and a polyether polyester urethane resin (B), said polyurethane resin (A) contains a polyol with molecular weight of 500 to 5,000 by 0 to 50 weight %, said polyol being obtained by adding alkylene oxide to a diol having cyclic structure, said polyurethane resin (A) also contains a diol having cyclic structure and/or a short-chain diol with molecular weight of 200 to 500 by 15 to 50 weight %, said short-chain diol being obtained by adding alkylene oxide to diol, said polyurethane resin contains ether groups obtained from said diol and said polyol by 1.0 to 5.0 mmol/g to the total quantity of the polyurethane resin.

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 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 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 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

A magnetic recording medium comprising a nonmagnetic support having on at least one side thereof a magnetic layer comprising a ferromagnetic particle and a binder, wherein the binder comprises a polyvinyl acetal resin having a polar group and a polyurethane resin having a polar group; and a magnetic recording medium comprising (a) a nonmagnetic support having on at least one side thereof at least one of a lower magnetic layer comprising a ferromagnetic particle and a binder and a nonmagnetic layer comprising a nonmagnetic particle and a binder and (b) an upper magnetic layer comprising a ferromagnetic particle and a binder provided thereon, wherein at least the binder contained in the upper magnetic layer comprises a polyvinyl acetal resin having a polar group and a polyurethane resin having a polar group.

Magnetic recording medium having a magnetic layer comprising

A negative type silver halide photographic material is disclosed, which comprises a support having thereon at least one silver halide emulsion layer and at least one other hydrophilic colloidal layer, wherein at least one said silver halide emulsion layer or at least one said other hydrophilic colloidal layer contains a hydrazine derivative and a polyacrylamide derivative.

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Odawara, Japan

Masaki Satake