Victor Company of Japan, Limited

Jvc Victor Company of Japan, Ltd.

Kuniharu Fujiki

Ikuo Matsumoto

Satoshi Sekiya

Shigeru Hashimoto

Yukio Matsumoto

Hiroshi Yoshida

Hiroshi Togashi

Kazuhiro Takeda

On a polymeric substrate, there is formed with a single magnetic layercontaining a ferromagnetic metal and oxygen. The magnetic layeris divided into three regions equally in the depth direction from the polymeric substrateto the surface of the magnetic layer, wherein the three regions are defined as a first regiona second regionand a third regionrespectively in accordance with a process of forming the magnetic layer. With defining that a maximum value of oxygen concentration in the first regionis 'Max', a minimum value of oxygen concentration in the second regionis 'Min', and a maximum value of oxygen concentration in the third regionis &#x201c;Max&#x201d; respectively, these values &#x201c;Max&#x201d;, &#x201c;Min&#x201d; and &#x201c;Max&#x201d; have relations of &#x201c;Min&#x201d;&#x3c;&#x201c;Max&#x201d; and &#x201c;Min&#x201d;&#x2266;&#x201c;Max&#x201d;&#x2266;&#x201c;Max

Magnetic recording medium possessing a magnetic layer having plural oxygen-containing regions

Magnetic paint for producing a magnetic recording medium, the magnetic paint comprises at least ferromagnetic powder, binder, .alpha.-Fe.sub.2 O.sub.3 powder, and alumina powder. A relationship between an additive amount (A) of the .alpha.-Fe.sub.2 O.sub.3 powder and an additive amount (B) of the alumina powder is 5.ltoreq.(A+B).ltoreq.25 weight-parts referred to 100 weight-parts of the ferromagnetic powder and 1.ltoreq.A/B.ltoreq.9. The binder comprises polyurethane resin containing metal base sulfonic acid and tertiary amine as major ingredients.

Magnetic recording medium and magnetic paint therefor

A magnetic recording medium comprising a non-magnetic support and a magnetic recording layer formed on at least one side of the support. The layer is made of a composition which comprises two types of polyesters as a binder. The polyesters have glass transition temperatures of not lower than 50.degree. C. and not higher than 10.degree. C., respectively.

Magnetic recording medium having two types of polyester binders in a

A magnetic recording medium comprising a non-magnetic support and a magnetic recording layer formed on the support through an undercoat layer. The undercoat layer is made of a combination of a thermosetting polyurethane resin, carbon black and an ammonium salt of a phosphoric ester of the following formula ##STR1## in which each R.sub.1, each R.sub.2 and R.sub.3 independently represent an alkyl group having from 1 to 18 carbon atoms, alkoxy group having from 1 to 4 carbon atoms, an or phenyl group. Preferably, in the formula, each R.sub.1 represents CH.sub.3, each R.sub.2 represents an alkyl group having from 1 to 14 carbon atoms, and R.sub.3 represents --OCH.sub.3 or a phenyl radical. The undercoat layer may further comprise a thermosetting polyester resin so as to improve adhesiveness.

Magnetic recording medium comprising an undercoat layer made of specific

Magnetic recording mediums comprising a nonmagnetic substrate and a magnetic recording layer formed on at least one side of the substrate. The magnetic recording layer is made of a composition which comprises magnetic particles dispersed in a combination of polyester and polyurethane resins and oleic acid, so that the magnetic medium is significantly improved in durability and lubricating property.

Magnetic recording medium

A magnetic recording medium which comprises a non-magnetic support, and a magnetic layer formed on the support through an undercoat layer is described. The undercoat layer is made of a cured product of a mixture of a thermosetting polyurethane resin and a thermosetting polyester used in an amount of not greater than 10 wt % of the polyurethane resin. The undercoat layer further comprises a phosphate ester.

Magnetic recording medium comprising an undercoating made of a mixture

A magnetic recording medium comprising a nonmagnetic support, and a magnetic recording layer formed on said support. The magnetic recording layer comprises a magnetic powder and an abrasive powder dispersed in a resin binder. The abrasive powder has a coating of an isocyanate compound having at least two isocyanate groups in one molecule thereof and is used in an amount of from 0.5 to 20 parts by weight per 100 parts by weight of the magnetic powder.

Magnetic recording medium comprising a surface-treated abrasive

A magnetic recording medium of the high recording density type is disclosed, which comprises a support, and a magnetic recording layer formed on at least one side of the support. The magnetic recording layer is made of a dispersion, in a binder, of magnetic alloy particles and TiO particles in an amount of from 0.1 to 20 wt % of said magnetic alloy particles.

Magnetic recording media of the high recording density type comprising

Magnetic recording media are described which comprise a support having a magnetic recording layer thereon. The magnetic recording layer is made of a dispersion of magnetic particles in a binder and a specific type of organosilicone. The organosilicone is represented by the general formula ##STR1## in which R represents a monovalent saturated or unsaturated hydrocarbon having 7 to 21 carbon atoms, R.sub.1, R.sub.2 and R.sub.3 independently represent a methyl or RCOO group, R.sub.4 is a saturated hydrocarbon group having 1 to 20 carbon atoms, and k, l, m and n are independently an integer provided that 1&lt;K, 1.ltoreq.l&lt;200, 1.ltoreq.m&lt;200, 0.ltoreq.n&lt;300, and l+m+n.ltoreq.500.

Magnetic recording media comprising organosilicones in a magnetic layer

Magnetic recording media are described which comprise a support having a magnetic recording layer thereon. The magnetic recording layer is made of a dispersion of magnetic particles in a binder and a specific type of fatty acid-modified, fluorinated organosilicone. The organosilicone is represented by the general formula ##STR1## in which R.sub.1 represents a monovalent saturated or unsaturated hydrocarbon having 7 to 21 carbon atoms, R.sub.2 represents a methyl or phenyl group, each R.sub.3 represents a OCOR.sub.1 in which R.sub.1 has the same meaning as defined above, Y represents --CF.sub.3 or --(CF.sub.2)--.sub.k W in which k is an integer of from 1 to 8, and W is hydrogen or fluorine, and l, m and n are independently an integer provided that 0.ltoreq.l&lt;200, 1.ltoreq.m&lt;100, 1.ltoreq.n&lt;100, and l+m+n.ltoreq.300.

Magnetic recording media comprising fluorinated organosilicones in a

A magnetic recording medium which comprises a support and a magnetic layer formed on the support and comprised of a magnetic powder dispersed in a binder and also of a lubricant. The lubricant contains at least an ester of a linear aliphatic acid having 14-18 carbon atoms and an alcohol of the general formula, ##STR1## in which R and R' are independently a linear alkyl group having 5-10 carbon atoms. Preferably, an ester of a linear aliphatic acid having 14-18 carbon atoms and a linear or branched alcohol having 4-8 carbon atoms are also contained in the magnetic recording medium.

A magnetic recording medium which comprises a support and a magnetic layer formed on the support which is comprised of a magnetic powder dispersed in a binder and containing a lubricant. The lubricant contains at least as ester of a linear aliphatic acid having 14-18 carbon atoms and an alcohol of the general formula, (CH.sub.3).sub.2 CH--(CH.sub.2).sub.n --OH in which n is an integer of from 1 to 5. Preferably, an ester of a linear aliphatic acid having 14-18 carbon atoms and an alcohol of the formula, CH.sub.3 --(CH.sub.2).sub.m --CH.sub.2 OH, in which m is an integer of from 2 to 4 is contained.

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Mito, Japan

Kuniharu Fujiki