Tdk Corporation

Kiminori Tamai

Tadayoshi Iijima

Takashi Handa

Shigeo Kurose

Kiyotaka Okuyama

Chieko Yamada

Shigeyo Miyamori

Hiroshi Kawahara

Yasufumi Takasugi

Yoichi Yoshimura

A functional film of the invention includes a microparticulate-containing layer containing functional microparticulates. The microparticulate-containing layer inhibits the occurrence of cracks even when drawn 10%. When the functional film includes a microparticulate-containing layer containing conductive microparticulates, the microparticulate-containing layer exhibits a surface resistivity after drawn 10% which is at most 10 times greater than the surface resistivity prior to drawing. The invention thus implements a functional film which is unsusceptible to reduction or loss of its function due to deformation.

Functional film

An object of the present invention is to provide functional films which can exhibit a variety of functions using functional fine particles, in particular, a transparent conductive film having a low resistance value using conductive fine particles. The functional film of the present invention is a functional film comprising a support and a functional layer on at least one surface of the support, wherein the above functional layer contains functional fine particles, and a ratio (&sgr;1/&sgr;2) between a dispersion value (&sgr;2) obtainable from the alignment of the functional fine particles at the front surface of the functional layer and a dispersion value (&sgr;1) obtainable from the alignment of the functional fine particles at the opposite surface of the functional layer is from 1.2 to 1.85. Thereby, a sufficient contact of the functional fine particles is effected in the functional layer and the strength of the functional layer and the adhesiveness between the functional layer and the support become large, so that a transparent conductive film wherein conductive fine particles are used as the functional fine particles, for example, has a low electric resistance.

Functional film having specific surface dispersion ratio

An object is to provide magnetic recording medium having a densely packed, highly oriented magnetic layer by enhancing the dispersibility of magnetic powder having a carbon or iron carbide base surface. Magnetic powder is pretreated by kneading and dispersing it with an organic solvent and optionally, an anionic or ampholytic surfactant and a fatty acid, and a resin containing an amino group or ammonium salt group is used as a binder.

Magnetic recording medium

In a magnetic recording medium of the coating type using a metal magnetic powder, for the purpose of improving switching field distribution (SFD) and electromagnetic properties, there is used a metal magnetic powder based on iron and containing Al and/or Si and a rare earth element, the content of Al and/or Si being 0.5 to 8% by weight based on the iron and the content of rare earth element (inclusive of Y) being 1 to 10% by weight based on the iron, and optionally 6 to 30% by weight of Co, preferably having a length of 0.06 to 0.30 .mu.m and an aspect ratio of from 4 to 15.

A magnetic recording medium includes a non-magnetic support and a magnetic layer, The magnetic layer comprises a binder and a Co-containing iron-based metal powder dispersed in the binder, characterized in that particles of the metal powder have a greater Co concentration in their surface layer than their inside of the particles, The Co-containing metal powder is easily dispersed in a binder and provides high Br/Bm and orientation. If Ba is contained in the starting powder the localization of Co in the surface area is realized.

A magnetic layer containing a magnetic powder whose surface is composed mainly of carbon and/or iron carbide and a binder is provided on a non-magnetic substrate, the magnetic layer further contains an organic dye compound having at least one polar group selected from the group consisting of a hydroxyl group, a carboxylic acid group, a sulfonic acid group and a salt thereof, and the binder contains an amino group and/or an ammonium salt group. Due to the improved dispersibility of a magnetic paint, the magnetic recording medium of the invention is improved in surface morphology, magnetic properties, and electromagnetic properties.

Magnetic recording medium comprising a magnetic layer containing

Iron carbide particles are heat treated in a nitrogen atmosphere to form magnetic particles each comprising an iron base core and a carbon base surface. This magnetic particle powder having increased saturation magnetization .sigma.s is mixed with a binder to form a magnetic layer on a substrate, thus providing a magnetic recording medium which exhibits improved remanence Br and reproduces increased outputs.

Magnetic recording medium comprising a magnetic coating containing

A metal magnetic powder for magnetic recording media consisting essentially of iron is obtained by providing a hydrous needle-like iron oxide powder as a starting material, applying cobalt ions on the surface thereof, and subsequently reducing the resultant powder in a reducing atmosphere. The metal magnetic powder contains cobalt in an amount not less than 6 weight % relative to iron, and the coercive force of the powder is not more than 1600 Oe.

Magnetic powder for magnetic recording media and method for producing

A metallic magnetic powder treated with an alkyl group-containing dicarboxylic acid so that the acid is deposited on the particle surfaces. The amount of the acid so deposited ranges from 0.5 to 5% on the basis of the weight of the starting powder.

Growing community of inventors

Nagano, Japan

Kiminori Tamai