Fuji Photo Film Company, Limited

Norio Nasu

Nobutaka Yamaguchi

Masaaki Fujiyama

Kenichi Masuyama

Nobuo Tsuji

Eiichi Tadokoro

Toshimitu Okutu

Takahito Miyoshi

Katsumi Ryoke

Yasutoshi Okuzawa

Shinobu Iida

Takashi Yoneyama

Nobuo Aoki

Shin-Ichiro Dezawa

Masahiro Utsumi

Masaaki Fujiyana

A magnetic recording medium is described, comprising a non-magnetic support having coated thereon on opposite surfaces a magnetic layer containing a magnetic substance and a binder-containing backing layer, wherein the magnetic layer has a light transmittance of 2% or more for light having a wavelength of 900 nm, the backing layer has a transmittance of from 1 to 10% for light having a wavelength of 900 nm, the magnetic recording medium as a whole has a transmittance of 1% or less for light having a wavelength of 900 nm, and the backing layer has a center line average roughness (Ra) of 0.05 .mu.m or less at a cut-off value of 0.08 mm.

Magnetic recording medium

A magnetic recording medium comprised of a nonmagnetic support base having a magnetic recording layer on one surface thereof and a backing layer on the other surface thereof is disclosed. The backing layer is comprised of (1) carbon black having a particle size in the range of 10 to 150 m.mu., (2) graphite having a particle size of 3.mu. or less, and (3) a curing agent. By utilizing this particular backing layer the resulting recording medium has improved durability with respect to the backing layer and shows a decreased in the number of dropouts and scratches during use.

A magnetic recording material, which comprises a non-magnetic support having provided on one side thereof a magnetic layer and on the other side thereof a backing layer is disclosed. The binder of the backing layer is comprised of a combination of a cellulose resin, a vinylidene chloride resin, a polyurethane resin and a polyisocyanate. Use of the backing layer increases the durability of the tape and aids in preventing drop out.

A magnetic recording medium is disclosed which comprises a non-magnetic support, having a Young's modulus of 7.times.10.sup.10 to 1.times.10.sup.13 dyn/cm.sup.2, having coated on opposite surfaces, a magnetic recording layer comprising ferromagnetic particles and a fatty acid ester and a backing layer comprising a cellulose resin.

A method for preparing a magnetic recording medium is described, comprising (1) pre-dispersing ferromagnetic particles having an S.sub.BET specific surface area of 35 m.sup.2 /g or more and having an adjusted water content of 0.8 wt % or more with a binder, (2) adding an additional binder and a lubricating agent thereinto, mixing and dispersing them to prepare a diserpsion of a magnetic coating composition, and (3) coating the resulting dispersion of a magnetic coating composition on a non-magnetic support.

Method for preparing magnetic recording medium

A magnetic recording medium comprised of a nonmagnetic support base having a magnetic layer provided thereon is disclosed. The magnetic layer includes ferromagnetic particles dispersed in a binder in combination with carbon black particles. The carbon black particles have an average primary particle size in the range of 30 m.mu. to 50 m.mu.. Further, the carbon black is capable of the adsorption of 120 ml or more of dibutyl phthalate per 100 g of carbon black. By utilizing the particular carbon black of the present invention it is possible to obtain a magnetic recording medium having improved running properties.

Magnetic recording medium having improved running properties

A magnetic recording medium is disclosed which is comprised of a non-magnetic support base having a magnetic layer on one surface and a silicone oil layer formed on the opposite surface. The silicone oil layer does not produce dropouts and eliminates scraping and therefore eliminates dust particles that collect and build up in the area of the magnetic head. The silicone layer is formed from a silicone-containing compound having a viscosity of at least 6,000 centistokes at 25.degree. C.

In a magnetic recording medium comprising a magnetic recording layer on the surface of a non-magnetic support member, an abrasive having a Mohs' hardness of at least 6 and needle-shaped .alpha.-Fe.sub.2 O.sub.3 are incorporated in the magnetic layer, thus improving the coating durability and decreasing the head abrasion, jitter and noise.

In a magnetic recording medium comprising a magnetic recording layer on the surface of a non-magnetic support member, a ferromagnetic powder, an abrasive having a Mohs' hardness of at least 6, colloidal silica and a fatty acid and fatty acid ester are incorporated in the magnetic layer, thus improving the durability of the magnetic layer and decreasing the head abrasion.

The present invention relates to an improved magnetic recording medium comprising a magnetic recording layer on the surface of a non-magnetic support, in which the magnetic recording layer contains a fatty acid, high viscosity silicone oil and fatty acid ester.

Growing community of inventors

Kanagawa, Japan

Norio Nasu