Fuji Photo Film Company, Limited

Nobuyoshi Asada

Masatoshi Takahashi

Naoto Murao

Mikio Ohno

Hiroshi Hashimoto

Kiyomi Ejiri

Katsumi Ryoke

Masashi Aonuma

Eiichi Tadokoro

Yuichiro Murayama

Noburo Hibino

Nobuyuki Kobayashi

Satoshi Matsubaguchi

Youichi Hayata

Jun-ichi Nakamigawa

A magnetic recording medium is disclosed, comprising a support having thereon a lower layer containing a nonmagnetic powder or a ferromagnetic powder dispersed in a binder, and at least a magnetic layer containing a ferromagnetic powder dispersed in a binder provided on the lower layer, wherein the binder contains a polyurethane resin obtained from a polyester polyol comprising a specific diol, a chain extending agent and an organic diisocyanate, and the magnetic layer surface has a C/Fe peak ratio of from 7 to 11.

Magnetic recording medium

Provided is a thin magnetic tape with good tracking and very little output variation in VTRs. The magnetic tape comprises a flexible support, a magnetic layer provided on one side of said flexible support and a backcoat layer provided on the reverse side of said flexible support. The magnetic tape has a stiffness equal to or less than 70 mg&middot;mm in the width direction, an average meandering amount of a tape edge trajectory traced by each of both end in the width direction of said tape observed from the direction perpendicular to said magnetic layer surface is equal to or less than 15 &mgr;m in every end, and an intensity of a meandering component having a cycle of 20 to 200 mm is equal to or less than 30 percent of the intensity of a meandering component having a cycle of 20 to 10,000 mm.

Magnetic tape having specific meandering features

A magnetic recording medium having a total thickness of not more than 11 .mu.m is disclosed, comprising a non-magnetic support having a magnetic layer comprising a ferromagnetic powder dispersed in a binder provided on one surface of the non-magnetic support and a back layer provided on the other surface of the non-magnetic support, wherein the non-magnetic support has a longitudinal Young's modulus (E.sub.MD) and a crosswise Young's modulus (E.sub.TD) such that the sum of E.sub.MD and E.sub.TD is not less than 1,200 kg/mm.sup.2 and the ratio of E.sub.MD to E.sub.TD is from 1/1 to 1/3 and an intrinsic viscosity of from 0.50 to 0.60 and the magnetic layer comprises a polyurethane resin with a weight-average molecular weight of from 30,000 to 60,000 having a component having a molecular weight of not more than 5,000 in an amount of not more than 4.5%.

In the present invention, the anti-scrapability of the back layer of a magnetic recording medium is improved to reduce the frequency of occurrence of powder fall onto the surface of the magnetic layer and clogging between the magnetic head and the surface of the magnetic layer. As a result, a magnetic recording medium which is extremely less susceptible to dropout can be provided. A novel tape-shaped magnetic recording medium is provided which is obtained by longitudinally slitting a nonmagnetic support having on one side thereof a magnetic layer comprising a ferromagnetic powder dispersed in a binder and on the other side a back layer, wherein the edge face of said back layer doesn't protrude from the vertical line tangent to the highest protrusion on the slit section of said nonmagnetic support.

Magnetic recording tape having a backcoat and specified edge profile

A magnetic recording medium is disclosed, comprising a magnetic layer comprising a ferromagnetic powder and a binder provided on one side of a non-magnetic support and a backing layer provided on another side of said non-magnetic support, wherein said ferromagnetic powder is a ferromagnetic metal powder comprising Fe as a main component Co and containing Y in an amount of from 1 to 5 atm-% based on the total weight of Fe and Co in said ferromagnetic metal powder, and said binder comprises a polyurethane mainly comprising a diol component composed of a polyether polyol and a polyester polyol and a polyisocyanate component.

A magnetic recording medium is disclosed, comprising a nonmagnetic support having provided on a first side of the support a magnetic layer containing a ferromagnetic powder and a binder, the ferromagnetic powder is a ferromagnetic metal powder having a water-soluble calcium content of 100 ppm or less, and the ratio of widthwise stiffness (TD) to lengthwise stiffness (MD) of the magnetic recording medium is in the range of from 0.65 to 1.00. In a preferred embodiment, the magnetic layer contains a saturated aliphatic acid having 14 to 24 carbon atoms, the magnetic layer has a dry thickness of from 0.5 to 3.5 .mu.m, the nonmagnetic support has a thickness of from 8 to 11 .mu.m, and the magnetic recording medium further comprises a backing layer having a dry thickness of from 0.1 to 1.0 .mu.m.

The present invention relates to a magnetic recording medium which comprises a non-magnetic support having coated on opposite surfaces thereof a magnetic layer and a backing layer comprising a resin as a binder and non-magnetic particles, wherein the resin binder contains a polyurethane resin, a copolymer of vinylidene chloride and acrylonitrile, and a polyisocyanate compound; the non-magnetic particles contains fine carbon black having an average particle size of 30 to 150 m.mu. and coarse carbon black having an average particle size of 160 to 600 m.mu.; and the mixing weight ratio of the resin binder to the non-magnetic particles is within the range of 0.375:1 to 1:1 by weight. This magnetic recording medium has excellent electromagnetic properties and running durability.

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Kanagawa, Japan

Nobuyoshi Asada