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.

公开(公告)号：JPH0628663A

公开(公告)日：1994-02-04

申请号：JP11827293

申请日：1993-05-20

Applicant: BASF MAGNETICS GMBH

Inventor： HERUMAN RORAA ,  PEETAA ENGERUHARUTO ,  RAINHORUTO BAURU ,  MIHIYAERU BOBURITSUHI ,  BUERUNAA RATSUERU ,  BUERUNAA RENTSU ,  RUDORUFU ZUYUTEINGAA

IPC: G11B5/66 ,  G11B5/73 ,  G11B5/733 ,  G11B5/735 ,  G11B5/704

Abstract: PURPOSE: To prepare a dispersion liquid to form a back layer which shows no decrease in gloss or increase in roughness, nor decrease in mechanical characteristics such as wear resistance by completing dispersion under specified technical conditions and then maintaining the stable state. CONSTITUTION: The magnetic recording carrier consists of a nonmagnetic base tape, a magnetic layer formed on the principal surface of the base tape, and a back coating layer comprising a polymer binder, nonmagnetic filler and supporting pigment. The back layer contains 15 to 40vol.% precipitated silica to the whole volume. The precipitated silica contains 98 to 99.5 % SiO2 and has pH=5 to 7 and 90 to 650m /g specific surface area. The surface of the silicate is covered with a polyurethane by 0.05 to 0.25g/m coating amt. This polyurethane has 40000 to 120000 average mol.wt. Mw and contains 10 to 100mg equiv. phosphate groups per 1kg of polyurethane.