Abstract: A magnetic recording medium is disclosed. The recording medium comprises a non-magnetic support and a plurality of magnetic layers being provided on a surface of the support, whereinone of the plural magnetic layers comprises a magnetic material comprising a magnetite iron oxide in which the ratio of divalent iron component Fe.sup.2+ to a trivalent iron component Fe.sup.3+ is0.13.ltoreq.Fe.sup.2+ /Fe.sup.3+ .ltoreq.0.45in atomic number ratio;the other magnetic layers each comprises a magnetic material other than the magnetite iron oxide; andthe non-magnetic support has from 100,000/mm.sup.2 to 4,000,000/mm.sup.2 of protuberances on its surface opposite to the surface on which the magnetic layers are provided.

Abstract: A magnetic recording medium having two magnetic layers is disclosed. The magnetic recording medium has a surface fatty acid content of 0.38 to 2.53 .mu.g per square centimeter and a magnetic layer closest to a support contains ferromagnetic powder of Co-containing FeOx wherein x represents 1.33 to 1.43. It is improved in electromagnetic conversion characteristics, light-shielding property and erasing property, and is suitably used for audio or video recording medium.

Abstract: A magnetic recording medium is disclosed which is excellent in the electro-magnetic conversion efficiency and inhibited drop-out. The magnetic recording medium cpomprises a non-magnetic support; a non-magnetic layer comprising a carbon black and a binder and being provided on the non-magnetic support; and a magnetic layer containing ferromagnetic metal particles comprising iron and aluminum or a magnetic layer containing tabular-shaped magnetic particles having an axis of easy magnetization with the direction perpendicular to the tabular surface, in which the magnetic layer is provided on the side of the non-magnetic layer farther fron the support by wet-on-wet coating procedure and has a dry thickness of from 0.3 .mu.m to 4.0 .mu.m.

Abstract: A magnetic recording medium is disclosed which is excellent in video and audio signal output as well as in S/N ratio. The recording medium comprises first and second magnetic layers provided on a support in this order from said support and the first magnetic layer has a SFD value of from 0.38 to 0.60 and the second magnetic layer has a SFD value of from 0.30 to 0.45, wherein SFD is defined as follows:SFD=.DELTA.H/Hcwhere .DELTA.H is a half-width of magnetic field at the extreme value of differential coefficient of a magnetic induction-magnetic field hysterisis curve, and Hc is a coercive force of a magnetic material.

Abstract: A magnetic recording medium and manufacturing method thereof are disclosed. The recording medium comprisesa support,a plurality of magnetic layer being provided on a surface of the support, anda backcoat layer being provided on the other surface of the support and comprising a binder and a carbon black, whereinan outermost magnetic layer being provided at the outermost portion from the support among said plurality of magnetic layers comprises, a binder, a magnetic powder and a carbon black in which the weight ratio of the carbon black to the magnetic powder is 0.1 to 0.5 percent,a magnetic layer other than the outermost magnetic layer comprises a binder, a magnetic powder different from the magnetic powder contained in the outermost layer and a carbon black in which the weight ratio of the carbon black to the magnetic powder is zero to 0.4 percent.The plurality of magnetic layers are coated on the support under a condition of wet on wet.

Abstract: There is disclosed a magnetic recording medium having excellent dispersability of ferromagnetic powder and ensuring stable production as well as excellent durability and electromagnetic conversion properties. The recording medium comprises a non-magnetic support and provided thereon at least one magnetic layer containing a ferromagnetic compound, wherein at least one of the magnetic layers contains:a fatty ester of 0.05 to 2 parts by weight per 100 parts by weight of the magnetic powder and,a binder composed of a urethane resin prepared from isocyanate and polyesterpolyol comprising carboxylic acid and diol represented by the following Formula I: ##STR1## wherein R represents a hydrocarbon group having 1 to 6 carbon atoms; and R' represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, provided that the total number of carbon atoms included in R and R' is 3 to 10 and that at least one of R and R' is a branched alkyl group having 3 or more carbon atoms.

Abstract: A coating apparatus having a first slot between its front and center edges and a second slot between its center and back edges, wherein a coating solution is extruded continuously from each of the slots onto the surface of a flexible support running continuously along the edge surfaces of the front, center, and back edges in that order.The front edge surface has a straight-line portion on at least the terminal end portion of the front edge so that the straight-line portion extends along the direction of movement of the support and is not longer than one mm, and at least one portion of the center and back edge surfaces protrudes from the extension line of the straight-line toward the support.The coating apparatus is suitable for preparing magnetic recording media.

Abstract: A medium recording medium is provided which has a plurality of coated layers on a nonmagnetic base support, a least one of said coated layer containing a modified copolymer having introduced therein an anionic functional group which forms an intramolecular salt.

Abstract: A magnetic recording medium which has improved electromagnetic conversion characteristics and running ability and is suitable for high-density recording. The magnetic recording medium has at least two magnetic layers which are provided on one side of a support. One of said magnetic layers contains magnetic particles having an aspect ratio of from 3 to less than 8 and the other one contains magnetic particles having an aspect ration of from 8 to 12.

Abstract: A magnetic recording medium and its manufacturing method are disclosed. The medium comprises a non-magnetic support and, provided thereon, a first magnetic layer coated by a first magnetic coating solution and a second magnetic layer coated by a second magnetic coating solution in this order, wherein a dry thickness of the first magnetic layer represented by .mu.m, t.sub.1, a dry thickness of the second magnetic layer represented by .mu.m, t.sub.2, the solid content of the first magnetic coating solution represented by weight %, W.sub.1, and the solid content of the second magnetic coating solution represented by weight %, W.sub.2 have the following relation,2.0.ltoreq.(t.sub.1 /W.sub.1) / (t.sub.2 /W.sub.2).ltoreq.15.

Abstract: A magnetic recording medium is disclosed, which has excellent electro-magnetic conversion characteristics and is improved in drop-out. The magnetic recording medium comprises a non-magnetic support and a plurality of magnetic layers provided on the support, and the magnetic layer being provided farthest from said support among these magnetic layers comprises a magnetic powder and a carbon black in an amount of not more than 1 part per 100 parts by weight of said magnetic powder; and another magnetic layer comprising a magnetic powder has a thickness of not more than 2.5 .mu.m, and 900 nm light-transmittance of said magnetic medium is not more than 0.1%.

Abstract: A magnetic recording medium improved in the magnetic recording characteristics, running properties and durability is disclosed. The magnetic recording medium comprises a non-magnetic support having on a side of the support an upper magnetic layer positioned farther from the support and a lower magnetic layer positioned closer to the support. The upper magnetic layer comprises a binder, a magnetic powder having an original BET specific surface area of not less than than 30 m.sup.2 /g and at least one abrasive selected from alumina, silicon carbide, Cr.sub.2 O.sub.3, silica, .alpha.-Fe.sub.2 O.sub.3, TiO.sub.2 and zilconia in a portion of 3 to 20 parts per 100 parts by weight of the magnetic powder, and the lower magnetic layer comprises a binder and a magnetic powder having an original BET specific surface area of less than 30 m.sup.2 /g, and kinds of the binders each contained in the upper magnetic layer and the lower magnetic layer are the same.

Abstract: A magnetic recording medium is disclosed. The medium comprises a non-magnetic support and, provided thereon in order, a first magnetic layer and a second magnetic layer each containing a magnetic material and a binder. Rmax, a maximum roughness, and Ra, a center line average roughness, of a surface of the support on the magnetic layer side, d.sub.1, a thickness of the first magnetic layer, and d.sub.2, a thickness of the second magnetic layer, have the following relation,4.times.10.sup.-3 .ltoreq.Ra/d.sub.1 .ltoreq.1.8.times.10.sup.-24.times.10.sup.-2 .ltoreq.Rmax/d.sub.1 .ltoreq.4.5.times.10.sup.-1d.sub.2 .ltoreq.1.0 .mu.

Abstract: A magnetic recording medium having plural magnetic layers is disclosed. The uppermost magnetic layer contains an abrasive with an average particle diameter of not more than 0.3 .mu.m, and a magnetic layer other than the uppermost magnetic layer contains an abrasive with an average particle diameter of not less than 0.3 .mu.m. The medium is improved in the electromagnetic conversion characteristics and sliding noise.

Abstract: There is disclosed a magnetic recording medium comprising a support and provided thereon a plurality of layers. The layers comprise an outermost magnetic layer and a lower magnetic layer, wherein the outermost magnetic layer contains carbon black having an average primary particle size ranging from 40 m.mu. to 300 m.mu., and the lower magnetic layer contains carbon black having an average primary particle size ranging from 5 m.mu. to 30 m.mu..

Abstract: A magnetic recording medium is disclosed, which has excellent electro-magnetic conversion characteristics and is improved in drop-out. The magnetic recording medium comprises a non-magnetic support and a plurality of magnetic layers provided on the support, and the magnetic layer being provided farthest from said support among these magnetic layers comprises a magnetic powder and a carbon black in an amount of not more than 1 part per 100 parts by weight of said magnetic powder; and another magnetic layer comprising a magnetic powder has a thickness of not more than 2.5 .mu.m, and 900 nm light-transmittance of said magnetic medium is not more than 0.1%.