Victor Company of Japan, Limited

Tunehide Naruse

Toshikazu Nishihara

Hiromasa Isono

Noboru Takahashi

Sadao Ozaki

Yukio Matsumoto

Ikuo Matsumoto

Yasushi Sasaki

Manabu Habu

Makoto Kato

Takeshi Ikushima

A magnetic metallic powder comprising iron or iron-cobalt as its fundamental component and, besides, molybdenum in an amount of 0.05 to 5% by weight of the fundamental component. The magnetic powder is produced by heat reduction of a molybdenum-doped iron oxide powder which may optionally contain cobalt. The presence of molybdenum suppresses agglomeration of the heated particles and produces an improvement on the coercive force of the metallic powder.

Magnetic iron powder containing molybdenum

A magnetic recording medium which comprises a support, and a magnetic recording layer formed on the support, the magnetic recording layer being comprised of a major proportion of a magnetic metal powder and minor proportions of a metal oxide powder, the metal oxide powder serving as a wear-resistant agent, an organic binder and ethylene stearyl bisamide serving as a lubricant.

Magnetic recording medium

A magnetic recording composition comprising a non-aqueous dispersion, in liquid dispersion medium, of a dispersed solid phase of a major proportion of magnetic powder and minor proportions of at least two types of non-magnetic powder. One type of the non-magnetic powder has a Mohs' hardness of greater than 7, inclusive, and is contained in an amount of from 1 to 5 wt% of the magnetic powder. The other type of the non-magnetic powder has a Mohs' hardness of smaller than 7 but greater than about 3 and is contained in an amount of from 1 to 15 wt% of the magnetic powder. Either one type or the other type of the non-magnetic powder can be composed of two different kinds of non-magnetic materials whose total amount should be within the above-recited range.

Magnetic recording composition and article coated therewith

A binder composition for magnetic recording tape which comprises polyisocyanate and a vinyl chloride-vinyl acetate copolymer non-reactive with the polyisocyanate, the copolymer being used in larger proportion. A resin or elastomer which is not reactive with the polyisocyanate may be added as a third component to impart flexibility or other desirable properties to the magnetic layer of tape.

Binder composition for magnetic recording tape

A magnetic recording composition comprising, in solvent, a magnetic powder, a resinous binder and, as a lubricant, an ester of isostearyl alcohol and a monobasic fatty acid containing from 6 to 16 carbon atoms or cetyl isooctanoate contained in an amount of 0.5 to 20 wt % of the binder. The composition can further comprise triolein as another lubricant component in an amount of 0.5 to 10 wt % of the binder, the total amount of the ester and triolein being in the range of 1 to 20 wt % of the binder.

Magnetic recording composition

A magnetic material for magnetic recording media, comprising acicular particles of a conventional magnetic material and a ferrite powder amounting to about 0.5-20 Wt% of the acicular particles. Preferably the ferrite powder has a roundish particle shape. The use of this magnetic material in the form of a dispersion of the acicular magnetic particles and the ferrite particles in a usual binder makes it possible to afford improved rectangular ratio to the recording media by a conventional orientation process.

Magnetic material for recording media

A magnetic recording composition which comprises a magnetic powder, a resinous binder, and triolein or a mixture of triolein and hexyl laurate as a lubricant. When used singly, triolein is used in an amount of 0.5 to 10 wt % of the binder. When used in combination, on the other hand, the total amount is in the range of up to 20 wt % of the binder while using the triolein in the range of 0.5 to 15 wt. % of the binder.

A magnetic metallic powder which is essentially of iron or its alloy with at least one other metal and features a good resistance to oxidation by air as well as a large value for saturation magnetization is obtained by the reduction of an oxide powder prepared or treated in a basic liquid phase environment the oxide powder ultimately to have a pH value not smaller than 6.0. A magnetic recording medium consisting of a nonmagnetic base and a thin magnetic layer comprising the metallic powder dispersed in a polymer binder serves for high density recording purposes and long retains its excellent physical properties.

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Yokohama, Japan

Tunehide Naruse