公开(公告)号：JPH02292725A

公开(公告)日：1990-12-04

申请号：JP9418190

申请日：1990-04-11

Applicant: BASF AG

Inventor： HORUSUTO PURATSUTSU ,  PEETAA ENGERUHARUTO ,  FURIIDORITSUHI ZOMAAMAN ,  ARUBERUTO KOORU ,  YURUGEN KURAUSUMAN ,  RAINHORUTO BAURU ,  PEETAA HAIRUMAN ,  HERUMAN RORAA

IPC: G11B5/84 ,  G11B5/842

Abstract: PURPOSE: To improve the recording properties of a magnetic recording medium by producing a dispersion in a mixing and pulverizing machine filled with pulverizing balls having a specific diameter and density. CONSTITUTION: The dispersion is produced in the mixing and pulverizing machine filled with the pulverizing balls having a diameter of 0.2 to 3.0mm and a density of 3.6 to 3.9g/cm . The dispersion is post-treated in a ball mill including pulverizing balls having a diameter larger than 2.0mm and a density larger than 4.2g/cm . The dispersion is so produced that the viscosity of the resulted dispersion, measured at 25 deg.C is at least 50mPas and that the added particulate magnetic material has at least 14m /g as the surface layer measured by a BET method. Consequently, the stable dispersion is produced without increasing a dispersant ratio and/or stabilizer ratio by using the known effective dispersion assembly. As a result, the magnetic properties are intrinsically improved and the recording properties of the resulted magnetic recording medium are improved.

公开(公告)号：JPH01149219A

公开(公告)日：1989-06-12

申请号：JP27108888

申请日：1988-10-28

Applicant: BASF AG

Inventor： AUGUSUTO REENAA ,  ARUBERUTO KOORU ,  HERUMAN RORAA ,  BUERUNAA RENTSU ,  RUUTOBUIHI KURAITONAA ,  HERUMUUTO KOPUKE ,  FURIIDORITSUHI ZOMAAMAN ,  ERUNSUTO RITSUKAA

IPC: C09D5/23 ,  C09D175/00 ,  C09D175/04 ,  G11B5/70 ,  G11B5/702

Abstract: PURPOSE: To improve the weatherability of a magnetic film by incorporating specific hydrocarbon into a magnetizable layer at a specific ratio of a magnetizable material. CONSTITUTION: The magnetizable layer contains hydrocarbon of carbon atomicity of 16 to 40 having 3 to 10 pieces of satd. branch positions at a ratio of 0.1 to 2.0wt.% of the weight of the magnetizable material. The more preferable hydrocarbon is such that polyisobutene of carbon atomicity of 16 to 32 having 4 to 8 pieces of the satd. branch positions and more particularly, the polyisobutene of carbon atomicity of 22 to 28 having 5 to 7 pieces of the satd. branch positions occupy therein at least up to 60%. As a result, the weatherability is improved.