Fuji Photo Film Company, Limited

Hajime Miyatsuka

Akihiro Matsufuji

Akira Kasuga

Yasuyuki Yamada

Masashi Aonuma

Tatsuji Kitamoto

Shigeo Komine

Nobuyuki Yamamoto

Shizuo Umemura

Masaaki Fujiyama

Tsutomu Okita

Takahito Miyoshi

Nobuo Tsuji

Yasuo Nishikawa

Noburo Hibino

Takeshi Kakuta

Takao Ohya

A magnetic recording medium comprises a nonmagnetic support and a magnetic recording layer containing a ferromagnetic powder which is provided on the support. The magnetic recording layer contains a binder resin having a acid residue or a salt thereof and a fatty acid ester compound having the formula (I): ##STR1## wherein R is a hydrocarbon group having 11-21 carbon atoms, R.sup.1 is hydrogen atom or a hydrocarbon group having 1-3 carbon atoms, and R.sup.2 and R.sup.3 are the same or different and each is a hydrocarbon group having 1-8 carbon atoms. The total number of carbon atoms contained in R.sup.1, R.sup.2 and R.sup.3 being not less than 3 carbon atoms. Alternatively, the fatty acid ester can be coated on the magnetic layer.

Magnetic recording medium using a fatty acid ester lubricant wherein the

A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a magnetic layer containing CrO.sub.2 fine particles and a binder, wherein the binder comprises polycarbonate polyurethane in an amount of from about 30 to about 90 wt %, based on the total weight of said binder.

Magnetic recording medium

A magnetic recording medium is disclosed, comprising a non-magnetic support having provided on one side thereof a magnetic recording layer comprising a binder having dispersed therein fine ferromagnetic particles and on the other side thereof a backing layer, wherein at least one of said magnetic layer and backing layer contains (1) a vinyl chloride resin having --SO.sub.3 M (wherein M is Li, Na, or K) groups and epoxy groups, and (2) polyurethane as binders. The medium has reduced output variation and improved running durability.

A magnetic recording medium comprising a nonmagnetic support and a magnetic recording layer provided on the support, said magnetic recording layer comprising a binder and a ferromagnetic powder dispersed therein, which is characterized in that said binder is composed of a resin component comprising:

In a magnetic recording medium such as a video tape comprising a nonmagnetic support and a magnetic recording layer provided on the support, said magnetic recording layer comprising a binder and a ferromagnetic powder dispersed therein, the improvement in which:

A magnetic recording medium such as a video tape comprising a magnetic recording layer which comprises a ferromagnetic metal powder having a specific surface area of not less than 42 m.sup.2 /g and an inorganic material powder having a Mohs' scale of hardness of not less than 5, wherein at least 90 wt. % of said inorganic material powder consists of particles having a particle size of 0.1-0.6 .mu.m, 51-85 wt. % of a portion of said particles consisting of particles having a particle size of less than 0.3 .mu.m, and the residual portion consisting of particles having a particle size of not less than 0.3 .mu.m.

A magnetic recording medium is disclosed which comprises a non-magnetic support having provided thereon a magnetic layer containing ferromagnetic metal particles and a binder, wherein the ferromagnetic metal particles have a specific surface area of 30 m.sup.2 /g or more, and a saturation magnetization of 120 emu/g or more and have been surface-treated with an organic compound. Also, a magnetic recording medium is disclosed which comprises a non-magnetic support having provided thereon a magnetic layer containing ferromagnetic particles and a binder, wherein the ferromagnetic particles have been surface-treated with an organic compound and the binder has essentially no functional groups which adsorb onto ferromagnetic metal particles.

The tape running property of a magnetic recording medium is improved by provision a back layer. This magnetic recording medium comprises a magnetic layer on one side of a non-magnetic support and a back layer on the other side thereof, in which the magnetic layer consists mainly of a ferromagnetic metal powder and a binder and has a coercive force of at least 1000 Oe and a surface roughness of at most 0.03 .mu.m, the ferromagnetic metal powder having a specific surface area of at least 35 m.sup.2 /gr and a saturation magnetization of at least 120 emu/gr, while the back layer has a surface electric resistance of at most 1.times.10.sup.10 .OMEGA. and a surface roughness of at most 0.05 .mu.m.

A magnetic recording medium which comprises a non-magnetic support having thereon a magnetic recording layer containing ferromagnetic metal particles and a binder, wherein the ferromagnetic metal particles have a specfic area of about 35 to about 80 m.sup.2 /g, and the magnetic recording layer has a surface roughness of about 0.001 to 0.04 .mu.m and a residual amount of the solvent is about 0.5 to about 30 mg/m.sup.2.

A magnetic recording medium for high-density recording, which comprises a non-magnetic substrate and a magnetic layer provided on the non-magnetic substrate and containing, as main constituents, ferromagnetic grains and a binder, wherein the non-magnetic substrate surface on the side adjoining the magnetic layer has a surface roughness higher than that of the back surface of the non-magnetic substrate. The substrate surface adjoining the magnetic layer has a surface roughness of 0.007.mu. or more, while the back surface has a surface roughness of 0.02.mu. or less, but in each particular application the roughness of the surface adjoining the magnetic layer is selected to be higher than that of the back surface.

Ferromagnetic metal particles are disclosed, which have a silane compound on the surface thereof. The silane compound is represented by the formula:

Ferromagnetic metal particles of iron alloyed with Ti, V, Cr, Mn, Co,

A ferromagnetic powder and process for producing it are disclosed. The process involves providing reducing a nickel-doped or nickel-coated iron compound in a reducing gas to provide a reduced metal powder including nickel in an amount of 3 to 30 atomic % based on the atomic % of iron present in the reduced metal powder, and treating the reduced metal powder with an organic metal powder. The resulting ferromagnetic metal powder has excellent stability with respect to oxidation and has a high saturation magnetization.

Ferromagnetic powder treated with an organic silane compound

A magnetic recording medium having a non-magnetic base overlaid with a magnetic layer containing ferromagnetic particles and a binder is disclosed. The ferromagnetic particles are metal particles and the binder is composed of (a) carboxyl-containing vinyl chloride/vinyl acetate copolymer, (b) a polyurethane resin and (c) a polyisocyanate compound.

Magnetic recording medium of ferromagnetic particles and binder

A magnetic recording medium having a non-magnetic base overlaid with a magnetic layer containing ferromagnetic particles is disclosed. The ferromagnetic particles are metal particles and the binder is composed of (a) a nitrocellulose and (b) a polyurethane resin.

A magnetic recording medium is disclosed comprising a non-magnetic base bearing a magnetic layer mainly consisting of ferromagnetic particles and a binder wherein the magnetic layer contains a polymer having a polar functional group and a degree of polymerization of not more than 100.

Growing community of inventors

Kanagawa, Japan

Hajime Miyatsuka