公开(公告)号：JPH06176346A

公开(公告)日：1994-06-24

申请号：JP21605493

申请日：1993-08-31

Applicant: BASF MAGNETICS GMBH

Inventor： HERUMUUTO YAKUSHIYU ,  KURAUSU DEIITAA SHIYOOMAN ,  MIHIYAERU FUITSUTSUFUERUTO ,  HERUMAN RORAA ,  RAINHORUTO BAURU ,  EDOBUIN ROOTOFUSU

IPC: C09D5/23 ,  C09D175/00 ,  C09D175/04 ,  G11B5/70 ,  G11B5/706 ,  G11B5/73

Abstract: PURPOSE: To obtain a magnetic recording medium which contains main chromium dioxide as a magnetic material and does not have the drawbacks of drop-outs in copying by a sprinter process method. CONSTITUTION: The magnetic memory medium consists of a nonmagnetic substrate and a magnetic layer applied thereon. This magnetic layer is obtd. by applying a dispersion prepd. by uniformly dispersing at least 40wt.% acicular ferromagnetic chromium dioxide in a polymer binder consisting of polyurethane as a base on the substrate, then drying the coating. The magnetic layer in particular has an inside surface area of 5 to 30m /cm and the pigment concn. PVC per volume attains 45 to 65%. The magnetic recording medium is thus made adaptable to the sprinter process of rapid copying.

公开(公告)号：JPH05135346A

公开(公告)日：1993-06-01

申请号：JP12021092

申请日：1992-05-13

Applicant: BASF MAGNETICS GMBH

Inventor： HERUMAN RORAA ,  PEETAA HAIRUMAN ,  MIHIYAERU HITSUTSUFUERUTO ,  DEIITAA SHIYUTOTSUKUBURUGAA ,  BUERUNAA RATSUTSUERU ,  RAINHORUTO BAURU ,  PEETAA ENGERUHARUTO ,  EDOBUIN ROOTOFUSU ,  BUERUNAA GURAU ,  BUERUNAA RENTSU

IPC: C09D5/23 ,  C09D127/04 ,  C09D127/06 ,  C09D175/00 ,  C09D175/04 ,  G11B5/73 ,  G11B5/735

Abstract: PURPOSE: To obtain a magnetic recording medium having good wear resistance by applying a magnetic layer on the main surface on one side of a web-like nonmagnetic substrate and applying a high mol.wt. binder and nonmagnetic additives on the rear surface layer on the opposite side of the main surface. CONSTITUTION: This magnetic recording medium consists of the web-like nonmagnetic substrate, the magnetic layer applied on the main surface on one side of this substrate and the rear surface layer formed on the opposite side of the main surface of the substrate from the high mol.wt. binder and nonmagnetic additives. The rear surface layer is formed by dispersing an org. polymer and a mixture composed of 2.5 to 25vol.% filler, 0.5 to 3vol.% auxiliary pigment and 1 to 10vol.% polyolefin of spherical particles having an average grain size of 1 to 1000μm at a density of 0.9 to 1.0 in the shape of the spherical particles. In addition, the resulted dispersion is applied on the front surface of the substrate existing on the opposite side of the magnetic layer at a layer thickness of such extent that a layer thickness of 0.1 to 2.0μm arises after the solidification of the rear surface layer. As a result, the magnetic recording medium having the excellent wear resistance and wear on the rear surface layer of the magnetic recording medium and simultaneously having transparency to light is obtd.