Abstract:
A servo track in the form of a patterned thin metallic film (15; 25) is disposed between a magnetic record medium (14;: 24) and a dielectric substrate (12; 22). The dielectric substrate (12; 22) can be in the form of a coating on a metallic substrate (11; 21). Where the magnetic record medium is composed of magnetic particles bound in a matrix, the matrix and the dielectric substrate are preferably composed of the same material. An additional layer (26, Figure 2) of dielectric material may be disposed between the metallic servo track film (25) and the magnetic record medium (24).
Abstract:
A urethane acrylate resin obtained by reacting a polyisocyanate with a polyester polyol having a molecular weight of 500 to 3,000, a low-molecular-weight polyol having a molecular weight of 60 to 400 and a hydroxyalkyl acrylate containing at least 70 mole % of a monohydroxyalkyl acrylate at an NCO/OH equivalent ratio in the range of 0.7 to 1.20. The composition comprising the above urethane acrylate resin affords crosslinked products having extremely excellent, tough physical properties, and can therefore be advantageously employed, for example, for base coatings for paper and polyethylene films prior to vacuum metallizing, protective coatings after vacuum metallizing, covering materials for electromagnetic tapes and floppy discs, vehicles for printing ink, adhesives. etc.
Abstract:
A magnetic recording medium such as a magnetic tape, which comprises a base film, a magnetic layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm 2 totally In both longitudinal and width direction which is higher than that of the base film, said magnetic layer being formed on one surface of the base film, and a backcoat layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm 2 totally In both longitudinal and width directions which is higher than that of the base film, said backcoat layer being formed on another surface of the base film, said magnetic recording medium having a total thickness of not more than 17 µ, said magnetic recording medium having excellent mechanical strength and being used without buckle and injury during usage even in a thin thickness.
Abstract:
A magnetic recording medium such as a magnetic tape, which comprises a base carrier and a magnetic layer formed on the base carrier, which is characterized in that the binder for forming the magnetic layer on the base carrier comprises a combination of at least one of resins selected from the group consisting of a vinyl chloridevinyl acetate copolymer resin, a polyvinylidene chloride resins, a phenoxy resin, an acrylic resin and a fibrillar resin, and a polyurethane resin containing 15% by weight or more of 4,4'-diphenylmethane diisocyanate, and optionally an isocyanate compound having a low molecular weight, said magnetic recording medium having excellent mechanical strength, excellent electrical characteristics and durability and being used without undesirable buckle, injury, curl of edge thereof during usage even in a thin thickness.
Abstract:
A magnetic recording medium comprises a film of an aromatic polyamide having at least 50 mole % of recurring units represented by the following general formula: wherein m and n are integers of from 0 to 4, with the proviso that the case where both of m and n are 0 is excluded, and at least one high performance magnetic layer of a metal or metal compound vacuum-deposited on the aromatic polyamide film. This magnetic recording medium shows a reduced dimensional change and is substantially free of curling or breakage due to elongation, and is excellent in flatness and adhesive strength between the base film and the magnetic layer. Accordingly, this magnetic recording medium is suitable for high-density magnetic recording.
Abstract:
An improved magnetic recording medium suitable for a high density recording, which has a squareness ratio in vertical direction being 0.6 or more and an orientation ratio (squareness ratio in vertical direction/squareness ratio in lengthwise direction) being 0.7 or more and is prepared from acicular magnetic iron oxide particles having crystalline magnetic anisotropy and a ratio of Fe 2+ /Fe 3+ of 0.05 or less wherein cobalt ion is uniformly doped, said particles having preferably a particle size of 0.3 µ or less and an axial ratio of 6 to 10, and a method for the production thereof.
Abstract:
A magnetic recording coating composition having a high density of magnetic particles uniformly dispersed in a high performance, thermoset polyurethane resin binder with the dispersion applied as a thin coating onto a rigid substrate. The thermosetting resin binder comprises a blocked isocyanate polymer reacted with a hydroxy terminated or branched polymer. The coating composition has an extended shelf life and can be cured at temperatures below 375°F to produce a smooth, hard, though durable and well dispersed magnetic coating with an improved orientation ratio that readily accepts buffing, washing, and lubrication.
Abstract:
In the manufacture of magnetic recording media, coatings are applied from water-borne dispersions of inorganic particles, a polymer containing functional groups and an agent for crosslinking the polymer, the crosslinking agent being a polyfunctional aziridine such as