Abstract: A magnetic recording medium having a total thickness of not more than 11 .mu.m is disclosed, comprising a non-magnetic support having a magnetic layer comprising a ferromagnetic powder dispersed in a binder provided on one surface of the non-magnetic support and a back layer provided on the other surface of the non-magnetic support, wherein the non-magnetic support has a longitudinal Young's modulus (E.sub.MD) and a crosswise Young's modulus (E.sub.TD) such that the sum of E.sub.MD and E.sub.TD is not less than 1,200 kg/mm.sup.2 and the ratio of E.sub.MD to E.sub.TD is from 1/1 to 1/3 and an intrinsic viscosity of from 0.50 to 0.60 and the magnetic layer comprises a polyurethane resin with a weight-average molecular weight of from 30,000 to 60,000 having a component having a molecular weight of not more than 5,000 in an amount of not more than 4.5%.

Abstract: A magnetic recording medium comprising on a non-magnetic support having thereon, in this order, an adhesive layer comprising a polymer, an undercoating layer comprising an inorganic powder and a binder, and one or more upper magnetic layers each comprising at least a ferromagnetic powder and a binder, the thickness of the upper magnetic layer being in the range of 0.05 to 1.0 .mu.m, the thickness of the undercoating layer being in the range of 0.5 to 5.0 .mu.m, the total thickness of the magnetic recording medium is in the range of 4 to 10 .mu.m, the micro vickers hardness of the non-magnetic support being in the range of 75 to 100 kg/mm.sup.2, and the micro vickers hardness of the undercoating layer being in the range of 25 to 50 kg/mm.sup.2.

Abstract: A magnetic recording medium comprising a nonmagnetic support and a magnetic layer, wherein the magnetic layer is provided on one surface of the nonmagnetic support, comprises a ferromagnetic particle, and has a surface roughness of from 2 to 10 nm; the nonmagnetic support has plural layers; at least one layer of the plural layers comprises an antistatic agent; and the nonmagnetic support has a surface roughness of from 5 to 30 nm on the opposite surface to the surface on which the magnetic layer is provided.

Abstract: A magnetic recording medium and a magnetic tape cassette are disclosed, comprising a non-magnetic support having formed on one surface only thereof at least two layers including a lower layer and an upper magnetic layer formed thereon, wherein the surface electric resistance (Rs) of the surface of the magnetic layer of said magnetic recording medium is 10.sup.9 .OMEGA./sq or less, the non-magnetic support contains at least three different kinds of particles which vary from each other in at least one property of mean particle diameter and Mohs' hardness, and the opposite surface of the magnetic recording medium comprises the rear surface of the nonmagnetic support having at least 1,000 projections having a height of from 200 nm to 400 nm per 0.1 mm.sup.2, but with the provisos that not more than 1,000 projections are present having a height of from 400 nm to 700 nm per 0.1 mm.sup.2 and not more than 50 projections are present having a height of 700 nm or more per 0.1 mm.sup.2.

Abstract: A magnetic recording medium is disclosed, which is formed by providing on a non-magnetic support, a lower layer comprising at least one of a ferromagnetic powder and a non-magnetic powder dispersed in a binder, and providing on the lower layer while the lower layer is in a wet condition, an upper magnetic layer comprising a ferromagnetic powder dispersed in a binder, wherein the upper magnetic layer has a dry thickness of 1.0 .mu.m or less, and the non-magnetic support is a multi-layer structural support comprising at least an uppermost support layer and a lowermost support layer, wherein the uppermost support layer is coated with the lower non-magnetic or magnetic layer, each of the uppermost layer and the lowermost layer comprises a biaxially oriented film comprising a thermoplastic resin containing filler particles, and the uppermost support layer has a center line average surface roughness Ra in the range defined by the following formula:Ra(Cut off: 0.25 mm)-Ra(Cut off: 0.08 mm).ltoreq.10 nm.

Abstract: A magnetic recording medium comprising a non-magnetic support having thereon a magnetic layer composed of ferromagnetic iron oxide powder dispersed in a binder, wherein a value of P.sub.10 of optical interference type three dimensional surface roughness on the magnetic layer side of the non-magnetic support is in the range of 15 to 35 nm, Rmax/P.sub.10 is not higher than 2.8 and P.sub.10 of the opposite side to the magnetic layer side is also in the range of 15 to 35 nm, wherein P.sub.10 (nm) represents the difference between an average height of the protrusions of 10 apices extracted in order of greatest height within an area 250 .mu.m square and an average height of all apices within the same 250 .mu.m square area and Rmax (nm) represents the difference between an uppermost height and a lowermost depth within the 250 .mu.m square area.

Abstract: A magnetic recording medium is disclosed, which comprises a non-magnetic support having coated thereon a magnetic layer, said non-magnetic support being a film substantially composed of polyethylene terephthalate and having a cutting index (Z) of 6 or less as defined by equation (1):Z=383.3-2.76A-2000B+840.DELTA.n (1)wherein A is the haze value, B is the surface orientation coefficient represented by {(n.sub.MD +n.sub.TD)/2}-n.sub.ZD, n.sub.MD is the refractive index in the machine direction, n.sub.TD is the refractive index in the transverse direction, n.sub.ZD is the refractive index in the thickness direction, and .DELTA.n is the difference of the refractive indices represented by n.sub.MD -n.sub.TD ; and said magnetic layer has yield elongation (L) of 10% or lower and requires energy (E) of 1.0 kg/mm.sup.2 or less to reach the yield point.

Abstract: A magnetic recording medium is described, comprising a non-magnetic support having coated thereon a non-magnetic layer and a magnetic layer in that order, with the surface roughness of the surface of the support on the side opposite from the magnetic layer being 0.007 .mu.m or more, and the non-magnetic layer being provided by coating and radiation-exposing a compound that is polymerizable by radiation exposure.

Abstract: A magnetic recording medium comprising a flexible support having coated thereon a magnetic layer is disclosed. The support has a surface roughness of from 0.01 to 0.1 .mu.m, the magnetic recording medium has a percent heat shrinkage of 1% or less in the direction of maximum shrinkage thereof after standing at 110.degree. C. for 4 hours, and the magnetic layer contains a metal or alloy fine powder as a ferromagnetic powder. The magnetic recording medium has a excellent running property after repeated use and a small percent heat shrinkage.

Abstract: A magnetic recording medium such as an audio cassette tape or a video cassette tape comprising a flexible nonmagnetic support and a magnetic recording layer which contains a ferromagnetic cobalt-containing iron oxide, in which the nonmagnetic support has a surface of a center line average height in the range of 0.01 to 0.1 .mu.m on both sides and the magnetic recording medium has a heat shrinkage ratio of not higher than 1%, the heat shrinkage ratio being determined after allowing to stand at 110.degree. C. for 4 hours.

Abstract: A process for preparing a magnetic recording medium is disclosed, which comprises (1) subjecting a surface of a non-magnetic support having a surface roughness of not less than 0.01 .mu.m to an abrasion treatment or a calendering treatment, (2) coating a layer containing a compound polymerizable by radiation exposure on the surface of non-magnetic support, (3) exposing the layer to radiation to polymerize and harden the same, and (4) providing a magnetic layer on the radiation exposed layer. The thus prepared magnetic recording medium is not accompanied by dropout due to "fish eyes" and is suitable for high density recording.

Abstract: Magnetic recording medium is disclosed which comprises a non-magnetic support having coated thereon a magnetic layer mainly containing ferromagnetic metal particles and a binder:(1) wherein the non-magnetic support is a polyester film having a thickness of 4 to 12 .mu.m, (b) an F5 value in a machine direction of 16 kg/mm.sup.2 or more, (c) a breaking strength in a machine direction of 25 kg/mm.sup.2 or more, (d) a breaking elongation in a machine direction of 90% or less, (e) a surface roughness (Ra) of 0.01 to 0.03 .mu.m, and (f) a fish eye (FE), which is shown in terms of height (H), of 6H or more having 0 per 100 cm.sup.2, a fish eye of 5H having 2 or less per 100 cm.sup.2 and a fish eye of 4H having 5 or less per 100 cm.sup.2 ;(2) wherein the ferromagnetic metal particles have (a) a saturation magnetization (.sigma.s) of 110 to 160 emu/g, and (b) a specific surface area measured by the BET method of 25 to 65 m.sup.

Abstract: A heat-treating process is disclosed. The process involves cutting a polymer support for a recording medium from a web roll of a long support base into a sheet form. The sheet or sheets in a superposed state are then heat-treated while applying pressure in the range of 1 g/cm.sup.2 to 1 kg/cm.sup.2 at a temperature of 50.degree. C. to 150.degree. C. for a period of time of 15 seconds to 24 hours. The heat treating process avoids conventional problems with respect to thermal shrinkage.

Abstract: A magnetic recording medium is disclosed which comprises a non-magnetic support having provided thereon a magnetic recording layer and a backing layer on the opposite surface thereof, wherein said magnetic recording layer contains a fatty acid, said backing layer contains a cellulose resin, and said non-magnetic support has a Young's modulus of 7.times.10.sup.10 to 1.times.10.sup.13 dyn/cm.sup.2.

Abstract: A magnetic recording medium is described, comprising a nonmagnetic support, a magnetic layer, and a nonmagnetic intermediate layer provided between the support and the magnetic layer, the nonmagnetic intermediate layer containing a radiation-polymerizable compound and finely divided particles, the nonmagnetic intermediate layer being polymerized by irradiation and having a surface roughness from about 0.001 to 0.02 .mu.m. This medium provides reduced gap loss between the medium and a magnetic head, and is suitable for use in high density recording.

Abstract: A magnetic recording medium for high-density recording, which comprises a non-magnetic substrate and a magnetic layer provided on the non-magnetic substrate and containing, as main constituents, ferromagnetic grains and a binder, wherein the non-magnetic substrate surface on the side adjoining the magnetic layer has a surface roughness higher than that of the back surface of the non-magnetic substrate. The substrate surface adjoining the magnetic layer has a surface roughness of 0.007.mu. or more, while the back surface has a surface roughness of 0.02.mu. or less, but in each particular application the roughness of the surface adjoining the magnetic layer is selected to be higher than that of the back surface.

Abstract: A method for the production of a magnetic recording medium is disclosed. The method involves coating a support base with a magnetic coating composition. The support base has a percent thermal shrinkage in the direction corresponding to the longitudinal direction of the support base of not more than 0.15%. The magnetic coating composition contains a compound having not less than two acrylate groups or methacrylate groups in the molecule and includes ferromagnetic fine powder dispersed therein. After coating the magnetic coating composition on the support base it is irradiated with an electron beam. The resulting medium has excellent electromagnetic properties, durability and improved tape skew characteristics. Further, the composition has good storage stability.

Abstract: A method for preparing a magnetic recording medium is disclosed. The method involves forming a thin magnetic layer on a polyester film by means of a vapor deposition or plating method, continually moving the film while maintaining it at a tension of 400 g/mm.sup.2 or less and contacting the moving film with a heating device at a temperature within the range of 70.degree. to 200.degree. C. for a period of time within the range of 0.1 to 30 seconds. The method provides a non-binder type magnetic recording medium having improved skew characteristics without formation of curls.

Abstract: A magnetic recording medium comprising a base and a magnetic layer formed thereon is disclosed. The coefficient of friction (.mu..sub.B) of the surface opposite to the magnetic layer in transversal direction against the axial direction of loading post is under the straight line represented by the formula: .mu..sub.B =0.1S.sub.TD -0.05 (wherein S.sub.TD is the stiffness of the medium in transversal direction and 0.5<S.sub.TD .ltoreq.6.0), and the total thickness of the medium is 15.5.mu. or less.

Abstract: The increased occurrence of jitter, wow, flutter, folding, and tendency to crumple of a magnetic recording medium when reducing the thickness of the support of the magnetic recording medium is effectively prevented by forming a thin glass layer on the base film for the magnetic recording medium.