摘要:
There is disclosed a flexible magnetic recording disk which is suitable as a high capacity magnetic disk for data recording and has an excellent durability. The flexible magnetic recording disk comprises a non-magnetic support having thereon a non-magnetic layer comprising a non-magnetic powder and a binder resin, and a magnetic layer comprising a ferromagnetic powder and a binder resin, in this order, wherein the magnetic layer has a thickness of 1 .mu.m or less, which is 1/2 or less of the thickness of the non-magnetic layer; and the magnetic layer further contains the abrasive particles which comprise a first abrasive particles having a Mohs' hardness of 6 or more and an average particle size of 0.8 to 1.4 times as large as the average particle size of the magnetic powder and a second abrasive particles having a Mohs' hardness of 6 or more and an average particle size of 2 to 4 times as large as the average particle size of the ferromagnetic powder.
摘要:
A magnetic recording disk having a good overwriting characteristic and an excellent electromagnetic characteristic, as well as superior running durability. The magnetic recording disk comprises a non-magnetic support having coated thereon, in the order, a non-magnetic layer comprising mainly a non-magnetic powder and a binder resin and a magnetic layer comprising mainly a ferromagnetic powder and a binder resin, wherein the magnetic layer is formed by applying a magnetic layer coating solution onto the coated non-magnetic layer while the non-magnetic layer remains in a wet condition, the average thickness of the magnetic layer is 0.5 .mu.m or less, and the maximum thickness and the minimum thickness thereof fall within the range of .+-.15% of the average thickness of the magnetic layer.
摘要:
A novel magnetic recording disc is provided comprising, a nonmagnetic support having thereon a nonmagnetic layer comprising nonmagnetic particles and a binder resin, and a magnetic layer comprising ferromagnetic particles and a binder resin, in this order. The nonmagnetic particles in the nonmagnetic layer are partially or entirely electrically conductive particles, the thickness of the magnetic layer is in the range of 0.5 .mu.m or less, and the orientation ratio of the ferromagnetic particles in the magnetic layer is 0.85 or more.A novel process for preparing the magnetic recording disc is provided. Further, a novel process for recording and reproduction of a signal having a shortest recordable wavelength of 1.5 .mu.m or less is provided, which utilizes the magnetic recording disc in conjunction with a magnetic head having a gap length (.delta.) of 0.50 .mu.m or less.
摘要:
A magnetic recording medium is described, comprising a nonmagnetic support having thereon a magnetic layer containing ferromagnetic particles which are a hexagonal system tabular particle, and which have an axis of easy magnetization in a direction of perpendicular to the major axis of the plate and are dispersed in a binder, wherein said ferromagnetic particles have a saturation magnetization of 60 emu/g or higher, a specific surface area (BET method) of from 25 to 70 m.sup.2 /g, an average particle diameter of from 0.01 to 0.2 .mu.m, and a coercive force of from 400 to 2000 oersteds, and said biner contains a resin having at least one kind of polar group in an amount of 1.times.10.sup.-5 eq/g or more of the polar group.
摘要:
A novel flexible magnetic disc is provided comprising a protective layer on the periphery of a central hole, wherein the protective layer comprises of two layers, the lower one of the two layers being a composition mainly composed of a printing ink and the upper one being a composition mainly composed of a resin obtained by irradiating a radiation-polymerizable compound with radiation so that it cures.
摘要:
Disclosed is a magnetic recording medium comprising a nonmagnetic support having thereon a magnetic layer comprising a ferromagnetic powder and a binder resin as the main components together with abrasive particles. The ferromagnetic powder is a hexagonal ferrite fine powder having particle sizes of from 0.01 to 0.2 .mu.m and a coercive force of from 600 to 2,000 Oe. The binder resin is composed of a polyurethane resin and/or a vinyl chloride resin each having at least one kind of a polar group, the abrasive particles are composed of a fine particle abrasive having a mean particle size of from 0.1 to 0.39 .mu.m and a coarse particle abrasive having a mean particle size of from 0.4 to 1.0 .mu.m, and the density of the coarse particle abrasive distributed in the vicinity of the surface of the magnetic layer is higher than that of the coarse particle abrasive distributed in the other region of the magnetic layer.
摘要:
A magnetic disc having excellent running durability is disclosed, which comprises a non-magnetic support and a magnetic layer on the non-magnetic support, the layer being composed mainly of a ferromagnetic metal powder and a binder resin, wherein the ferromagnetic metal powder has a pH value of less than 7.0 and a specific surface area as determined by the BET method of at least 40 m.sup.2 /g, and the glass transition temperature of the magnetic layer is at least 75.degree. C.
摘要:
A magnetic recording medium comprising a non-magnetic support having thereon a magnetic layer comprising ferromagnetic metal powder and a binder, the magnetic layer further comprising carbon black having an average particle diameter of 250 m.mu. or more in an amount of from 1 to 10 parts by weight per 100 parts by weight of the ferromagnetic metal powder, and an ester of tridecyl alcohol with stearic acid and/or an ester of tridecyl alcohol with palmitic acid in an amount of from 5 to 20 parts by weight per 100 parts by weight of the ferromagnetic metal powder.
摘要:
A magnetic recording medium is disclosed, comprising a nonmagnetic support having thereon a magnetic layer containing ferromagnetic particles which are dispersed in a binder and have a tabular hexagonal crystal shape with an axis of easy magnetization perpendicular to the plate, wherein said ferromagnetic particles have a specific surface area of from 50 to less than 70 m.sup.2 /g, and further said magnetic layer contains abrasive agents having a Mohs' hardness of 6 or more and having an average particle diameter of from 0.3 to 1.0 .mu.m in an amount of from 7 to 15 parts by weight per 100 parts by weight of the ferromagnetic particles.
摘要:
The magnetic signal reproduction system comprises a magnetic recording medium comprising a magnetic layer comprising a ferromagnetic powder and a binder on a nonmagnetic support; and a reproduction head, wherein a number of protrusions equal to or greater than 10 nm in height on the magnetic layer surface, as measured by an atomic force microscope, ranges from 50 to 2500/10,000 μm2, a quantity of lubricant on the magnetic layer surface, denoted as a surface lubricant index, ranges from 0.5 to 5.0, a surface abrasive occupancy of the magnetic layer ranges from 2 to 20 percent, and the reproduction head is a magnetoresistive magnetic head comprising a spin-valve layer.