摘要:
A disc-like magnetic recording medium is disclosed, which comprises a support having thereon a magnetic layer comprising a ferromagnetic powder and a binder as main components, wherein the ferromagnetic powder has an average long axis length of from 0.01 to 0.18 .mu.m, a crystallite size of from 50 to 180 .ANG., an acicular ratio of from 2 to 9, the magnetic layer has the coercive force Hc of from 1,700 to 3,000 Oe, the in-plane orientation ratio of 0.85 or more, and the squareness ratio in the vertical direction to the surface of the magnetic layer of 0.30 or less.
摘要:
Provided is a magnetic recording medium exhibiting good electromagnetic characteristics in high-density recording The magnetic recording medium employed for magnetically recording signals with a track width equal to or less than 2.0 μm and reproducing the magnetically recorded signals, wherein said magnetic recording medium comprises a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder or comprises a nonmagnetic layer comprise a nonmagnetic powder and a binder and a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder in this order on a nonmagnetic support. Said magnetic layer has a thickness equal to or less than 0.2 μm, and said hexagonal ferrite ferromagnetic powder has an average plate diameter being 1/30 or less of the magnetically recorded track width as well as ½ or less of the thickness of the magnetic layer.
摘要:
A magnetic recording medium is disclosed, comprising a support having provided thereon a substantially nonmagnetic lower layer by coating a lower layer coating solution comprising a nonmagnetic powder dispersed in a binder and drying, and a layer having a thickness of from 0.01 to 0.15 μm by coating a magnetic layer coating solution comprising a ferromagnetic metal powder or a hexagonal ferrite powder dispersed in a binder, wherein the magnetic layer contains diamond particles having an average particle size of from 1/5 to 2 times the thickness of the magnetic layer in an amount of from 0.1 to 5.0 mass % based on the ferromagnetic metal powder.
摘要:
A magnetic recording and reproduction method comprising recording or reproducing a track of a rotating magnetic disk by means of a magnetic head, wherein the magnetic disk comprises a support and a magnetic layer containing ferromagnetic powder and a binder; the track has a breadth of 2 μm or less; and a frictional force between the magnetic layer and the magnetic head at innermost peripheral area of a recording region of the magnetic disk is 30 mN or less, a frictional force between the magnetic layer and a magnetic head at outermost peripheral area of a recording region of the magnetic disk is 20 mN or less, and a ratio of the frictional force at the innermost peripheral area to the frictional force at the outermost peripheral area is from 1.0 to 4.0.
摘要:
A magnetic recording medium comprising: a nonmagnetic support; and at least one magnetic layer comprising a ferromagnetic hexagonal ferrite powder and a binder, wherein the magnetic layer comprises diamond particles having an average particle size of 0.03 to 0.5 &mgr;m in a ratio of 0.1 to 5% by weight to the ferromagnetic hexagonal ferrite powder, the ferrite hexagonal ferrite powder has an average tabular diameter of 5 to 40 nm, and the binder is at least one of: (i) a binder comprising from 0.2 to 0.7 meq/g of at least one polar group selected from —SO3M, —OSO3M, —PO(OM)2, —OPO(OM)2 and —COOM, wherein M represents a hydrogen atom, an alkali metal or ammonium, and (ii) a binder comprising from 0.5 to 5 meq/g of at least one polar group selected from —CONR1R2, —NR1R2 and —N+R1R2R3 wherein R1, R2 and R3 each independently represents a hydrogen atom or an alkyl group.
摘要:
A method for producing a magnetic recording medium comprising: dispersing at least a binder and a ferromagnetic hexagonal ferrite powder to prepare a magnetic coating; and applying the magnetic coating to provide at least one magnetic layer, wherein the binder is at least one of: (a) a binder comprising 0.2 to 0.7 meq/g of at least one polar group selected from —SO3M, —OSO3M, —PO(OM)2, —OPO(OM)2 and —COOM wherein M represents a hydrogen atom, an alkali metal or ammonium; and (b) a binder comprising 0.5 to 5 meq/g of at least one polar group selected from —CONR1R2, —NR1R2 and —N+R1R2R3 wherein R1, R2 and R3 each independently represents a hydrogen atom or an alkyl group, and the ferromagnetic hexagonal ferrite powder has an average tabular diameter of from 10 to 40 nm and a water content of from 0.3 to 3% by weight.
摘要:
A magnetic recording medium is disclosed comprising a non-magnetic support having provided thereon a plurality of magnetic layers containing a ferromagnetic powder dispersed in a binder, wherein the lower magnetic layer closest to the support contains as the binder at least one polyurethane resin having a glass transition temperature (Tg) of from -50.degree. C. to -10.degree. C., and the uppermost magnetic layer contains as the binder at least one polyurethane resin having a glass transition temperature of from more than 40.degree. C. to 100 .degree. C.The magnetic recording medium of the present invention exhibits excellent running durability as well as electromagnetic conversion characteristics.
摘要:
A magnetic recording and reproduction method comprising recording or reproducing a track of a rotating magnetic disk by means of a magnetic head, wherein the magnetic disk comprises a support and a magnetic layer containing ferromagnetic powder and a binder; the track has a breadth of 2 μm or less; and a frictional force between the magnetic layer and the magnetic head at innermost peripheral area of a recording region of the magnetic disk is 30 mN or less, a frictional force between the magnetic layer and a magnetic head at outermost peripheral area of a recording region of the magnetic disk is 20 mN or less, and a ratio of the frictional force at the innermost peripheral area to the frictional force at the outermost peripheral area is from 1.0 to 4.0.
摘要:
A magnetic recording medium comprising a support having provided thereon a magnetic layer containing a barium ferrite powder dispersed in a binder, wherein the concentration of Ba of the extract obtained by the following condition is 20 ppm or less per m2 of the magnetic recording medium: condition: 0.05 m2 of the magnetic recording medium is arbitrarily cut out and put in a 200 ml beaker with 100 ml of distilled water, the beaker is covered with a watch glass and retained in a constant temperature bath at 75° C. for 3 hours.
摘要翻译:一种磁记录介质,包括在其上设置有分散在粘合剂中的铁氧体粉末的磁性层的支撑体,其中通过以下条件获得的提取物的Ba浓度为每m 2磁记录20ppm以下 介质:条件:将0.05m 2的磁记录介质任意切出,并用100ml蒸馏水放入200ml烧杯中,用手表玻璃覆盖烧杯,并保持在75℃的恒温浴中 C. 3小时。
摘要:
A magnetic recording medium is disclosed, comprising a support having provided thereon a magnetic layer containing a ferromagnetic powder and a binder as main components, wherein the ferromagnetic powder is a hexagonal ferrite powder having an average tabular diameter of from 15 to 40 nm, the perpendicular factor of squareness ratio SQ of the magnetic layer is from 0.1 to 0.55, the specific surface area and the total pore volume per weight of the magnetic layer by a nitrogen adsorption method are from 0.1 to 50 m2/g and from 0.001 to 1 ml/g, respectively, and the magnetic layer thickness is from 0.02 to 0.3 &mgr;m.