Abstract: A method for manufacturing a magnetic recording medium is disclosed, comprising ferromagnetic alloy powders having an average length in the long axis of 0.3 .mu.m or less and a specific surface area (BET Method) of 45 m.sup.2 /g or more, by steps which comprise surface-treating the ferromagnetic alloy powders with at least one triazine thiol compound, dispersing the surface-treated powders in a binder, and then coating the binder containing the surface-treated powders on a nonmagnetic support, wherein the ferromagnetic alloy powders are surface-treated with a triazine thiol compound represented by formula (I) in a condition in which the moisture content of the ferromagnetic alloy powders is 0.5 wt % or less, in a system of substantially excluded moisture: ##STR1## wherein R represents R.sub.1 O--, R.sub.1 S--, R.sub.1 NH--, or R.sub.1 R.sub.2 N--R.sub.1 --, R.sub.1 and R.sub.

Abstract: An abrasive tape comprises a flexible substrate and an abrasive layer which is overlaid on the flexible substrate and which contains abrasive grains and a binder. The abrasive grains comprise first abrasive grains, which have a mean grain diameter within the range of 0.07 .mu.m to 0.40 .mu.m and a Mohs hardness within the range of 5 to 7, and second abrasive grains, which have a mean grain diameter within the range of 0.20 .mu.m to 0.60 .mu.m and a Mohs hardness not lower than 8.5.

Abstract: A magnetic recording medium comprising a non-magnetic support having provided thereon an intermediate layer comprising carbon black, a binder and ferromagnetic particles in a weight ratio of from 5% to 25% based on the carbon black; and a magnetic layer provided on said intermediate layer, wherein said magnetic layer comprises ferromagnetic particles and a binder.

Abstract: A magnetic recording medium whose output is increased over a wide range of from long wavelengths to short wavelengths and whose output fluctuation with rotation period is decreased when rotating and reproducing in the form of a disk is provided comprising a non-magnetic support and a magnetic layer provided thereon containing a ferromagnetic substance, the magnetic layer having a multilayer structure consisting of a lower layer containing a ferromagnetic substance in an ellipsoidal shape with ##EQU1## and a saturation magnetization of at least 60 emu/g and an upper layer containing a ferromagnetic substance of plate-shaped hexagonal system having the axis of easy magnetization in the vertical direction to the plate surface.

Abstract: A process for the preparation of a magnetic recording medium comprises the steps of subjecting a magnetic recording layer coated on a nonmagnetic support to surface smoothening treatment, the magnetic recording layer comprising a ferromagnetic powder dispersed in a binder, and then grinding both a surface of the magnetic recording layer and a surface of a back layer provided on the support using a specific grinder. The specific grinder is a fixed blade, a diamond wheel or a rotatable blade. A rotatable blade-grinder preferably employable for the grinding procedure comprises a rotatable body having a circular section and one or more blades provided on the periphery of the body.

Abstract: A magnetic recording medium having a magnetic layer is disclosed, comprising co-absorbed .gamma.-iron oxide particles as ferromagnetic particles and binders, wherein coercive force of Hc of the magnetic recording medium is 850 Oe or more and the ratio of the coercive force Hc and saturated magnetic flux density Bm thereof is 0.5/l or less.

Abstract: A magnetic recording medium comprising a nonmagnetic support, a magnetic recording layer provided on the support which comprises a binder and a ferromagnetic powder dispersed therein, and a monomolecular film or a built-up film provided on the magnetic recording layer. The monomolecular or built-up film comprises a saturated fatty acid having 10-24 carbon atoms and/or its alkali metal salt which is oriented vertically to the plane of the film. A process for the preparation of the same is also disclosed.

Abstract: An abrasive tape comprises a flexible substrate, and an abrasive layer overlaid on the flexible substrate by applying an abrasive coating composition containing abrasive grains and a binder onto the flexible substrate and drying the applied abrasive coating composition. The binder contains a vinyl chloride resin having a --SO.sub.3 M group, where M represents Li, Na or K, and an epoxy group.

Abstract: A process for producing a magnetic recording medium is disclosed, which comprises uniformly dispersing an .alpha.-Al.sub.2 O.sub.3 powder having a particle size of not greater than 0.1 .mu.m in a dispersion medium to obtain a dispersion, adding the dispersion to a coating composition for a magnetic layer essentially comprising a binder and a ferromagnetic powder having a specific surface area of not less than about 40 m.sup.2 /g, further dispersing the mixture to prepare a coating composition for a magnetic layer, and coating the resulting coating composition on a nonmagnetic support to obtain a magnetic layer having a dry thickness of about 2 .mu.m or less. The resulting magnetic recording medium exhibits excellent electromagnetic characteristics and improved abrasion resistance.

Abstract: An abrasive tape comprises a flexible substrate, and an abrasive layer overlaid on the flexible substrate by applying an abrasive coating composition prepared by use of abrasive grains and a binder onto the flexible substrate and drying the applied abrasive coating composition. The binder contains a vinyl chloride resin having a --SO.sub.3 M group, where M represents Li, Na or K, and an epoxy group, a resin having, at a side chain thereof, at least one polar group selected from the group consisting of--SO.sub.3 M, --OSO.sub.2 M, --OSO.sub.3 M, --COOM, and ##STR1## where M represents H, Li, Na or K, M.sub.1 represents H, Li, Na, K or an alkyl group, and M.sub.2 represents H, Li, Na, K or an alkyl group, and a polyisocyanate.

Abstract: In a magnetic recording medium comprising a nonmagnetic support, a magnetic recording layer provided on one surface of said support and a back layer containing carbon black provided on another surface of said support, the improvement wherein said back layer has thickness of not larger than 0.6 .mu.m and contains an inorganic filler powder having a Mohs' scale of hardness of not less than 5, a mean particle diameter of smaller than the thickness of the back layer and not smaller than 1/5 of the thickness thereof, and the maximum particle diameter of not larger than 11/10 of the thickness of the back layer.

Abstract: A method of making an abrasive tape comprises the steps of preparing an abrasive composition at least from abrasive grains and a binder, applying the abrasive composition onto a flexible substrate, and drying the applied abrasive composition. The step of preparing the abrasive composition comprises kneading processing and attritor dispersion processing which are carried out for at least a part of the abrasive grains and at least a part of the binder.

Abstract: Anti-static material is bonded to the portions of a magnetic tape cassette which are in close proximity to the magnetic tape when the tape is in motion. The anti-static material prevents a static charge being generated by frictional contact between tape and cassette, and therefore protects the tape from damage and erratic travel speed.

Abstract: A process for the preparation of a magnetic paint comprising a ferromagnetic powder, an abrasive and a binder, which comprises the steps of preparing the abrasive dispersion comprising the abrasive and the binder, and then mixing said abrasive dispersion and the ferromagnetic powder.

Abstract: Improvement in a process for the preparation of a magnetic recording medium which comprises the steps of applying a magnetic paint onto a surface of a nonmagnetic support to form a coated paint layer, said magnetic paint comprising magnetic recording layer-forming components including a ferromagnetic powder, an abrasive and a resin component dispersed in an organic solvent, and then subjecting the coated layer to magnetic orientation, in which a step of drawing the ferromagnetic powder in the coated magnetic paint toward the surface of the support by means of a magnet is arranged in advance of the orientation step.

Abstract: A magnetic recording medium which comprises a non-magnetic support having on the surface side thereof a magnetic recording layer and on the opposite side thereof a backing layer is disclosed. The backing layer contains carbon black and a binder and has a thickness of 2 .mu.m or less. The carbon black is composed of fine-grained carbon black having a mean grain size of 10 to 30 m.mu. and coarse-grained carbon black having a mean grain size of 100 to 150 m.mu.. In the backing layer the ratio of the content of carbon black to the binder ranges from 1:0.5 to 1:3.5 by weight.

Abstract: A magnetic recording medium comprising a nonmagnetic support and a magnetic recording layer provided on said support, said magnetic recording layer comprising a ferromagnetic metal powder having a specific surface area of not less than 45 m.sup.2 /g and an inorganic powder having a Mohs' scale of hardness of not less than 5 which are dispersed in a binder,wherein5-40 particles of said inorganic powder are arranged in the magnetic recording layer per (10 .mu.m).sup.2 of the surface area of said recording layer in such manner that a portion of each inorganic particle is exposed on of the surface of the magnetic recording layer; andthe average content of said inorganic powder in a portion of said recording layer within depth of 0.1 .mu.m from the surface thereof is higher than that in other portion of the magnetic recording layer.

Abstract: A magnetic recording medium is described which has, on a non-magnetic support, a magnetic layer comprising a ferromagnetic substance dispersed in a binder, wherein the ferromagnetic substance is a hexagonal tabular ferromagnetic substance having an axis of easy magnetization in the direction perpendicular to the plain thereof and the ratio of the bulk density to true density (bulk densy/true density) is at least 0.16. The magnetic recording medium has improved output and C/N.

Abstract: A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a magnetic layer having magnetic particles being ferromagnetic hexagonal crystallized tabular shape particles having an axis of easy magnetization in a direction vertical to a flat surface thereof, said binder being present in an amount of from 10 to 30 wt % based on the weight of the magnetic particles, and said binder comprising a polycarbonate polyurethane being present in an amount of from 20 to 60 wt %, a vinyl chloride and vinyl acetate type copolymer being present in an amount of from 20 to 70 wt %, and a polyisocyanate being present in an amount of from 10 to 60 wt %, based on the total amount of binder.

Abstract: A tape for cleaning magnetic head comprising a support and a cleaning layer coated on at least one surface of said support, which is characterized in that said cleaning layer contains a ferromagnetic metal powder as abrasive, the surface of said cleaning layer is a surface of center line average height of not less than 0.025 .mu.m as cut-off value of 0.08 mm, and said tape has a stiffness of not more than 2.