Abstract: A back coating resin composition for a magnetic recording medium comprising:(A) a plastic compound having a molecular weight of from 5,000 to 100,000 and containing at least two radiation-curable unsaturated double bonds;(B) a rubber-like compound having a molecular weight of from 3,000 to 100,000 and containing at least one radiation-curable unsaturated double bond or containing no such double bond; and(C) a compound having a molecular weight of from 200 to 3,000 and containing at least one radiation-curable unsaturated double bond.

Abstract: A magnetic recording medium comprising a ferromagnetic metal thin film layer primarily based on cobalt and formed on the surface of a flexible substrate, an organic topcoat layer containing a radiation curable compound having a molecular weight of less than 2,000, an anti-oxidant, and a lubricant on the surface of the metal thin film layer, and a backcoat layer containing an inorganic pigment, an organic binder, and a lubricant on the other surface of the substrate is provided with protrusions on its surface at an average density of at least 10.sup.5 /a.sup.2 per square millimeter of the surface, the protrusions having a height of 30 to 300 .ANG., where a is the distance of a gap in a magnetic head with which the medium is used in recording/reproducing operation.

Abstract: A magnetic recording medium comprising a ferromagnetic metal thin film layer primarily based on cobalt and formed on the surface of a flexible substrate, an organic topcoat layer containing a radiation-curable compound, an anti-oxidant, and optionally a lubricant on the surface of the metal thin film layer, and a backcoat layer containing an inorganic pigment, an organic binder, and a lubricant on the other surface of the substrate is provided with protrusions on its surface at an average density of at least 10.sup.5 /a.sup.2 per square millimeter of the surface, the protrusions having a height of 30 to 300 .ANG., where a is the distance of a gap in a magnetic head with which the medium is used in recording/reproducing operation.

Abstract: A magnetic recording medium comprising a ferromagnetic metal thin film layer primarily based on cobalt and formed on the surface of a flexible substrate, and an organic topcoat layer containing a radiation curable compound having a molecular weight of less than 2,000, an anti-oxidant, and a lubricant on the surface of the metal thin film layer is provided with protrusions on its surface at an average density of at least 10.sup.5 /a.sup.2 per square millimeter of the surface, the protrusions having a height of 30 to 300 .ANG. where a is the distance of a gap in a magnetic head across which the medium is passed in recording/reproducing operation.

Abstract: In a magnetic recording medium comprising a substrate and a magnetic layer thereon, the magnetic layer is formed by coating a composition of a binder, preferably radiation-curable binder and a plate magnetic material such as hexagonal plate barium or strontium ferrite having an average particle diameter d expressed in .mu.m and an average flakiness R satisfying the following equations: 0.1<d.ltoreq.0.15 and R.gtoreq.280d-22, passing the coating through a magnetic field to orient the magnetic plates, and curing the coating.

Abstract: A ferromagnetic alloy image recording tape, wherein the stiffness of the entire tape is represented by the formula: ##EQU1## where w: load (g)a: radius (mm) of the tape ringb: width (mm) of the taped: deformation (mm) of the tape ring

Abstract: A magnetic recording medium comprising a ferromagnetic metal thin film layer primarily based on cobalt and formed on the surface of a flexible substrate, an organic topcoat layer containing an anti-oxidant and a lubricant on the surface of the metal thin film layer, and a backcoat layer containing an inorganic pigment, an organic binder, and a lubricant on the other surface of the substrate is provided with protrusions on its surface at an average density of at least 10.sup.5 /a.sup.2 per square millimeter of the surface, the protrusions having a height of 30 to 300 .ANG., where a is the distance of a gap in a magnetic head with which the medium is used in recording/reproducing operation.

Abstract: A magnetic recording medium comprising a substrate, an optional undercoat layer, and a magnetic layer formed thereon and containing a hexagonal plate magnetic powder, an electroconductive material, and a binder is improved in runnability and recording density by the presence of a fatty acid ester at least on the recording side surface of the magnetic layer, and by providing an electric resistance of up to 5.times.10.sup.9 .OMEGA./cm.sup.2 on the side of the magnetic layer.

Abstract: In a coating type perpendicular magnetic recording medium intended for digital recording comprising a substrate and a magnetic layer thereon, the magnetic layer is formed from a composition of a binder, preferably radiation-curable binder and plate magnetic material such as hexagonal plate barium or strontium ferrit having an average particle diameter of up to 0.15 .mu.m and a flakiness of at least 6.

Abstract: A magnetic recording medium comprising a non-magnetic substrate and a coating type magnetic recording layer formed on the substrate, wherein barium ferrite magnetic powder is perpendicularly oriented, characterized in that an undercoating layer comprising a radiation curable binder and carbon black, is provided beneath the magnetic recording layer.

Abstract: A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, wherein the back coating layer contains an inorganic pigment having a Mohs hardness of at least 5 and carbon black, and the inorganic pigment is in an amount of at most 1/9 by weight relative to the carbon black.

Abstract: A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, characterized in that the back coating layer is a radiation-cured coating layer containing a fine particulate pigment having an average particle size of the primary particles of at most 50 m.mu.m and a specific surface area of at least 35 m.sup.2 /g as measured by BET method.

Abstract: A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, characterized in that the back coating layer is a coating layer comprising zinc sulfide and a resin binder.

Abstract: A coating type magnetic recording medium particuarly suitable as a mangetic disk is provided, which comprises a substrate and a magnetic layer of a plate magnetic powder and a binder on the substrate. Selection is made such that the plate magnetic powder has an average particle diameter of up to 0.2 .mu.m and an average flakiness of at least 2, the magnetic layer is up to 1.8 .mu.m thick, and the magnetic recording medium has a coercive force of a value x in Oe and a rectangular ratio Br/Bm of a value y both in a direction perpendicular to the magnetic layer surface, which fall in the range defined by the following equations:400.ltoreq.x.ltoreq.800, y.ltoreq.1, and0.5.ltoreq.y.ltoreq.0.75 where 750.ltoreq.x.ltoreq.800, and0.5.ltoreq.y.ltoreq.-0.001x+1.5 where 400.ltoreq.x<750.

Abstract: In a magnetic recording medium comprising a substrate and a magnetic layer thereon, the magnetic layer is formed by coating a composition of a binder, preferably radiation-curable binder and a plate magnetic material such as hexagonal plate barium or strontium ferrite having an average particle diameter of up to 0.1 .mu.m and a flakiness of at least 6, passing the coating through a magnetic field to orient the magnetic plates, and curing the coating.

Abstract: This invention concerns a radiation-curable, magnetic coating material and a magnetic recording medium made with the coating, which is characterized in that a water-soluble or water-dispersed resin having at least one radiation-curable, unsaturated double is contained as a vehicle. The vehicle may also contain a water-soluble or water-dispersible resin, or mixtures thereof free from such an unsaturated double bond. The invention provides a magnetic recording medium with improved durability, softness, flexibility, and heat resistance.

Abstract: A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, characterized in that the magnetic recording layer contains a hexagonal system plate crystal magnetic powder having a particle size of at most 0.2 .mu.m, and the back coating layer contains a binder composed of a radiation curable resin and has an electric resistance of at most 10.sup.10 .OMEGA./cm.sup.2.

Abstract: A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer of ferromagnetic film formed on one side of said substrate, and a topcoat layer comprising an antioxidant and a lubricant and formed on the surface of said magnetic recording layer.

Abstract: A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, wherein said back coating layer contains graphitized carbon black having an average particle size of from 10 to 50 m.mu.m as measured by an electron microscope.

Abstract: Magnetic recording tape comprising a ferromagnetic thin film on a non-magnetic base and having good running stability and low output fluctuation, clogging, and dropout can be obtained by making the stiffness of the overall tape0.149.times.wa.sup.3 /dxb=0.02 to 0.12 g mmwhereinw: load (g)a: radius of tape ring (mm)b: tape width (mm)d: deformation of tape ring (mm)The stiffness in the above formula can be determined by the method described in the specification.