Abstract: A magnetic recording medium includes a non-magnetic support and a magnetic layer, The magnetic layer comprises a binder and a Co-containing iron-based metal powder dispersed in the binder, characterized in that particles of the metal powder have a greater Co concentration in their surface layer than their inside of the particles, The Co-containing metal powder is easily dispersed in a binder and provides high Br/Bm and orientation. If Ba is contained in the starting powder the localization of Co in the surface area is realized.

Abstract: An 8 mm video tape cassette capable of rendering back-tension of a tape optimum to minimize damage to a tape edge and and clogging of a head. A hub of a feed reel on which a magnetic tape of 11.0 .mu.m or less in thickness is wound is formed with a diameter of 25 mm or more and preferably 25 to 31 mm.

Abstract: The magnetic recording medium of the invention has a magnetic layer formed by mixing an iron base metal magnetic powder with a binder, the metal magnetic powder being prepared by furnishing hydrous iron oxide or iron oxide powder as a starting material, applying Zr, Al, and Si compounds or Zr, Al, and Co compounds to the powder surface, and reducing the treated powder in a reducing atmosphere. Improved surface smoothness, a low coefficient of friction, and improved dynamic durability are achievable.

Abstract: A magnetic recording medium comprises a magnetic layer coated on a substrate and composed of ferromagnetic powder dispersed in a binder, wherein the magnetic layer contains TiO.sub.2 having an average particle size of at most 8 .mu.m and a surface area of at most 25 m.sup.2 /g as measured by a nitrogen adsorption method, and Al.sub.2 O.sub.3 having an average particle size of at least 0.1 .mu.m and a surface area of at most 30 m.sup.2 /g as measured by a nitrogen adsorption method.

Abstract: A magnetic recording medium is composed of a substrate coated with a magnetic layer comprising a magnetic powder and a binder, wherein the binder comprises from 20 to 60% by weight of a polyurethane resin, from 20 to 60% by weight of an epoxy resin, from 15 to 55% by weight of a vinyl chloride-vinyl acetate copolymer resin and a polyisocyanate.

Abstract: A magnetic recording medium comprises a magnetic layer coated on a substrate and composed of ferromagnetic metal or alloy powder dispersed in a binder, wherein the magnetic layer contains Al.sub.2 O.sub.3 having an average particle size of at most 1 .mu.m and an .alpha.-form rate of from 60 to 90%.

Abstract: A process for producing a magnetic recording medium, which comprises dispersing a ferromagnetic powder in a binder to form a magnetic coating composition and applying the magnetic coating composition onto a film base support to form a magnetic layer thereon, wherein corona discharge treatment is applied after the application and drying the magnetic coating composition on the film base support.

Abstract: A magnetic recording medium having a substrate coated with a magnetic layer comprises a magnetic powder and a binder, essentially consisting of 40 to 80 wt. % of a polyester resin, 60 to 20 wt. % of a nitrocellulose impregnated with vinyl chloride-vinyl acetate copolymer as a protective component and a polyisocyanate.

Abstract: A magnetic recording tape or disc which has excellent physical characteristics of adhesive strength, a repeated running durability, and a gloss degree of the surface as well as excellent electromagnetic characteristics. A binder of a magnetic paint coating comprises 30 to 70 wt. % of an urethane resin, 10 to 50 wt. % of an epoxy resin and 10 to 50 wt. % of nitrocellulose, and if necessary a curing agent.

Abstract: A magnetic recording tape or disc which has excellent total characteristics of an adhesive strength, a repeat running durability, an electromagnetic characteristic, a gloss degree of the surface and a curling is provided. A binder of a magnetic layer comprises 40 to 70 wt. % of a urethane resin, 15 to 40 wt. % of an epoxy resin and 10 to 40 wt. % of a phenoxy resin.

Abstract: In a magnetic recording medium having a substrate coated with a magnetic layer comprising a magnetic powder and a binder, an improvement characterized in that said binder in said magnetic layer essentially consisting of 20 to 60 wt. % of a polyurethane, 15 to 45 wt. % of a polyester resin and 20 to 50 wt. % of a vinyl chloride-vinyl acetate copolymer-impregnated nitrocellulose.

Abstract: A magnetic recording medium having a substrate coated with a magnetic layer comprising a magnetic powder and a binder essentially consisting of 20 to 70 wt. % of a polyester resin, 80 to 30 wt. % of a vinyl chloride-vinylidene chloride copolymer and a polyisocyanate.

Abstract: A magnetic recording medium has a substrate coated with a magnetic powder and a binder. The binder in said magnetic layer essentially consists of 15 to 45 wt. % of a polyester resin, 20 to 50 wt. % of an epoxy resin and 10 to 40 wt. % of nitrocellulose.

Abstract: A magnetic recording medium comprises a substrate coated with a magnetic layer formed by using a magnetic composition comprising a binder and a magnetic powder adsorbing ricinoleic acid or an ester thereof.

Abstract: A magnetic recording medium is provided which satisfies electromagnetic conversion characteristics and typical physical properties such as bonding strength, repeated-passage stability, still-playback characteristics, etc. without unfavorably affecting the surface smoothness. The binder in the magnetic coating contains in combination specific proportions of three components, a polyurethane resin, an epoxy resin, and a nitrocellulose whose protective ingredient has been replaced by a vinyl chloride-vinyl acetate copolymer is used as a resin binder in magnetic coating material together with a polyisocyanate curing agent.

Abstract: A magnetic recording medium comprises a substrate coated with a magnetic layer comprising a binder resin and a metallic magnetic powder supporting silica on the surface which is coated with sequential layers of hydrolyzed silane compound and oleic acid. A magnetic recording medium is produced by sequentially treating a metallic magnetic powder supporting silica on the surface with a solution of a hydrolyzable silane compound and a solution of oleic acid to obtain a magnetic powder having the coated sequential layers and admixing the coated magnetic powder with a binder resin to prepare a magnetic composition and coating the magnetic composition on a substrate to form a magnetic layer.

Abstract: A magnetic recording medium comprises a substrate coated with a magnetic composition comprising a magnetic powder in a binder comprising a vinyl chloride-vinyl acetate vinyl alcohol copolymer having more than 10 wt. % of vinyl alcohol component and a vinyl chloride polymer-impregnated nitrocellulose which is crosslinked with a polyisocyanate.

Abstract: A magnetic recording medium comprises a substrate coated with a magnetic layer wherein a magnetic powder is orientated in a cured binder comprising a vinyl chloride, vinyl acetate copolymer having more than 10 wt. % of vinyl alcohol component and a polyester and a nitrocellulose.