Konica Corporation

Tsutomu Kenpo

Takafumi Yanagita

Naoto Yamamoto

Yasuo Ando

Atsuko Matsuda

Disclosed is a magnetic recording medium comprising a nonmagnetic base support and a magnetic layer containing ferromagnetic metallic powder dispersed in a binder, wherein the strain dependability of said magnetic recording medium is characterized in that: a ratio G'.sub.2 /G'.sub.1 is not less than 0.01, wherein G'.sub.1 is a storage modulus provided that the strain is 10.sup.-4, and G'.sub.2 is a storage modulus provided that the strain is 10.sup.-2.

Magnetic recording medium

A magnetic recording medium comprising at least two magnetic layers provided on a non-magnetic support, and a backing layer on the support on the side opposite to said magnetic layers, wherein said backing layer has, on the surface thereof, the protrusions each having a height of the peaks thereof within the range of 0.05 .mu.m to 0.6 .mu.m wherein the amount of the protrusions is within the range of 10,000 to 100,000 cm.sub.2 and an interval of the peaks of not less than 10 .mu.m.

A magnetic recording medium having superior electromagnetic conversion characteristics and travel durability in a well balanced state. The recording medium comprises a non-magnetic support and a plurality of magnetic layers each comprising a ferromagnetic powder and a binder and each of the magnetic layers shows a peak of its loss modulus at a temperature not less than 50.degree. C. and the half-width of the loss modulus-temperature curve showing the peak of loss modulus is not larger than 20.degree. C.; and the temperature of the peak of loss modulas of the outermost magnetic layer provided at the outermost portion among the magnetic layers is higher than that of a magnetic layer other than the outermost magnetic layer.

Magnetic recording medium comprising plural magnetic layers wherein each

The method of improving a magnetic recording medium having a support, provided thereon a magnetic layer, and provided on an another side of the support a back coating layer, is disclosed. The improvement comprises the back coating layer containing a binder and a non-magnetic powder comprising essentially of a combination of carbon black and a non-magnetic particle selected from the group consisting of zinc oxide, titanium oxide, barium sulfate, ferric oxide and calcium carbonate.

A magnetic recording medium having plural magnetic layers is disclosed. The magnetic recording medium comprises a first magnetic layer containing magnetic powder having a coercive force of less than 800 Oe and a BET value of less than 45 m.sup.2 /g, a second magnetic layer containing magnetic powder having a coercive force of not less than 800 Oe and a BET value of less than 45 m.sup.2 /g and a third magnetic layer containing magnetic powder having a coercive force of not less than 800 Oe and a BET value of not less than 45 m.sup.2 /g, in this order.

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Hino, Japan

Tsutomu Kenpo