公开(公告)号：DE2540874A1

公开(公告)日：1977-03-24

申请号：DE2540874

申请日：1975-09-13

Applicant: BASF AG

Inventor： OHLINGER MANFRED DIPL CHEM DR ,  GRAU WERNER DIPL CHEM DR ,  STRITZINGER HEINZ DIPL ING ,  SCHOENAFINGER EDUARD DIPL CHEM

IPC: G11B5/706 ,  H01F1/36

Abstract: Prod. having high coercive force is produced by pptg. Co(OH)2 from a Co(II) salt soln. with ammonia onto goethite crystallised from an alkaline soln. The prod. is subjected to reduction into magnetite. Subsequently the magnetite is oxidised with O2 at 200-400 degrees C to produce cobalt doped gamma-Fe2O3. Process is improved by pretreating the surface of goethite (before the introduction of the Co(II) salt) with an acid having pK 4.8; adjusting pH to 3-7 and maintaining the surface acidity within this range to the end of the redn. process. gamma-Fe2O3 suitable for magnetic recording is produced. Its coercive force is increased (compared with the known material) by the increased quantity of the cobalt dopant. The above process permits an increase in the cobalt doping without impairing the thermal stability and the toughness of the product. The reduction stage can be carried out at temps. as low as 250-290 degrees C.

公开(公告)号：DE2443663A1

公开(公告)日：1976-03-25

申请号：DE2443663

申请日：1974-09-12

Applicant: BASF AG

Inventor： NAGEL PETER DIPL ING ,  GRAU WERNER DIPL CHEM DR ,  MAIER HERMANN DR ,  WITTKAMP HEINRICH DIPL ING ,  FALK ROLAND DIPL CHEM DR ,  WILLMANN PAUL ING GRAD

IPC: B65H20/12 ,  B65H27/00 ,  G11B5/84 ,  B65H17/30

Abstract: A high-speed roller system for transporting webs of sheeting, preferably for coating the same with a magnetic layer, comprising a suction roller for control of the speed of the web, which suction roller has a surface containing grooves, preferably rhombic grooves, in which the perforations for sucking the sheeting are disposed, preferably at the points of intersection, the ratio of the total cross-sectional area of the perforations to the total surface area of the roller being from 0.7 to 3%.

公开(公告)号：DE2752219A1

公开(公告)日：1979-06-07

申请号：DE2752219

申请日：1977-11-23

Applicant: BASF AG

Inventor： ELFF KLAUS ING GRAD ,  GRAU WERNER DIPL CHEM DR

IPC: B05D3/12 ,  B05D5/12 ,  G11B5/845 ,  B05D7/04 ,  B05D7/24 ,  G11B5/84

Abstract: The process involves application in layers of a pourable anisotropic material in a soln. of a polymer binding agent, and additives in an organic solvent, onto a non-magnetic carrier material. The magnetic anisotropic particles are aligned in the dispersion layer in a preferred direction, which is also to the plane of the carrier material. The coating is fastened and dried. Directly before application onto the carrier material, the dispersion is subjected to a penetrating magnetic field. The homogenous magnetic field has a field strength, which is higher or of the same size as the coercive field strength of the magnetic material used.

公开(公告)号：DE2909891A1

公开(公告)日：1980-09-25

申请号：DE2909891

申请日：1979-03-14

Applicant: BASF AG

Inventor： KNELLER ECKHART PROF DIPL PHYS ,  KOENIG ROLAND DIPL PHYS DR ,  KOESTER EBERHARD DIPL PHYS DR ,  GRAU WERNER DIPL CHEM DR ,  MAYER DIETER

IPC: G11B5/66 ,  G11B5/64 ,  G11B5/65 ,  G11B5/706 ,  G11B5/73 ,  G11B5/85 ,  H01F1/20 ,  H01F10/12 ,  H01F10/13 ,  H01F10/16 ,  H01F41/20 ,  H01F10/00 ,  B05D5/12 ,  C23C13/02 ,  C03C17/06 ,  C23C15/00

Abstract: A magnetic recording medium comprising a non-magnetic base which is dimensionally stable at up to 300 DEG C., and an 0.03-0.4 mu m thick magnetically hard recording layer of an Sm-Co alloy, vacuum-deposited thereon, which layer possesses uniaxial magnetic anisotropy in the plane of the layer, and a process for the manufacture of this recording medium.

公开(公告)号：DE2744887A1

公开(公告)日：1979-04-19

申请号：DE2744887

申请日：1977-10-06

Applicant: BASF AG

Inventor： ELFF KLAUS ING GRAD ,  BECKER HANS-JUERGEN DIPL CHEM ,  LOESER WERNER DIPL CHEM DR ,  JAKUSCH HELMUT DIPL PHYS DR ,  GRAU WERNER DIPL CHEM DR

IPC: C01G49/00 ,  C01G49/06 ,  G11B5/706 ,  C01G49/02 ,  C09C1/24

公开(公告)号：DE3217099A1

公开(公告)日：1983-11-10

申请号：DE3217099

申请日：1982-05-07

Applicant: BASF AG

Inventor： MELZER MILENA DIPL ING ,  JAKUSCH HELMUT DIPL PHYS DR ,  GRAU WERNER DIPL CHEM DR ,  KOESTER EBERHARD DIPL PHYS DR ,  LOESER WERNER DIPL ING DR ,  POLKE REINHARD DIPL PHYS DR ,  SCHAEDEL GUENTER DIPL ING DR ,  OHLINGER MANFRED DIPL CHEM DR ,  VAETH GUENTER

IPC: G11B5/70 ,  C09D5/23 ,  G11B5/68 ,  G11B5/706 ,  G11B5/84 ,  H01F1/11 ,  H01F1/113 ,  H01F1/44 ,  H01F41/16

Abstract: A magnetic dispersion which can be applied to a non-magnetic base to produce a recording medium is prepared by dispersing a magnetically anisotropic material in a polymer binder and in an organic solvent by a method wherein the magnetically anisotropic material is worked in a jet mill before and/or during dispersing.

公开(公告)号：DE3151590A1

公开(公告)日：1983-07-07

申请号：DE3151590

申请日：1981-12-28

Applicant: BASF AG

Inventor： MELZER MILENA DIPL ING ,  SCHNEIDER NORBERT ,  KOPKE HELMUT ,  SCHOETTLE KLAUS DIPL ING ,  KOESTER EBERHARD DIPL PHYS DR ,  BALZ WERNER DIPL CHEM DR ,  GRAU WERNER DIPL CHEM DR

IPC: C08L75/06 ,  C09D5/23 ,  C09D171/00 ,  C09D171/10 ,  C09D175/06 ,  G11B5/70 ,  G11B5/702 ,  G11B5/84 ,  G11B5/842 ,  G11B5/68 ,  B05D3/00 ,  B05D5/12

公开(公告)号：DE3136982A1

公开(公告)日：1983-03-31

申请号：DE3136982

申请日：1981-09-17

Applicant: BASF AG

Inventor： BACHMANN RUDOLF DIPL CHEM DR ,  BALZ WERNER DIPL CHEM DR ,  GRAU WERNER DIPL CHEM DR ,  GUTERMANN WINFRIED ,  KOVACS JENOE DIPL CHEM DR ,  KRUCKER KARL DIPL CHEM DR ,  RUDOLF PETER ING GRAD ,  SCHAEFER DIETER DIPL CHEM DR ,  HACK JOACHIM DIPL ING

IPC: C09D5/23 ,  C09D137/00 ,  G11B5/70 ,  G11B5/702 ,  G11B5/68 ,  B05D5/12

公开(公告)号：DE2617809A1

公开(公告)日：1977-11-03

申请号：DE2617809

申请日：1976-04-23

Applicant: BASF AG

Inventor： SCHOENAFINGER EDUARD DIPL CHEM ,  MOTZ HERBERT DIPL ING DR ,  OHLINGER MANFRED DIPL CHEM DR ,  DEIGNER PAUL DR ,  GRAU WERNER DIPL CHEM DR

IPC: G11B5/712 ,  C09C1/34 ,  C09C3/12 ,  C09D5/23 ,  C09D7/12 ,  G11B5/706 ,  H01F1/11 ,  C04B35/12 ,  C01G37/02 ,  B05D5/12 ,  G11B5/72

Abstract: Chromium dioxide magnetic pigments are stabilized against loss of their magnetic properties by treating them, in aqueous and/or alcoholic suspension, with a block copolymer consisting of siloxane units and alkyleneoxy units of 2 to 4 carbon atoms, the alkyleneoxy units being bonded to the polysiloxane radical by a Si-O-C or Si-C group, in an amount of from 1 to 40% by weight based on the chromium dioxide, after which the latter is separated off and dried at from 50 DEG to 200 DEG C. The stabilized chromium dioxide magnetic pigments may be used for the manufacture of magnetic recording media exhibiting improved stability of the magnetic properties under adverse climatic conditions.

公开(公告)号：DE2606832A1

公开(公告)日：1977-09-08

申请号：DE2606832

申请日：1976-02-20

Applicant: BASF AG

Inventor： JAKUSCH HELMUT DIPL PHYS DR ,  SAPPOK REINHARD DIPL CHEM DR ,  SCHOENAFINGER EDUARD DIPL CHEM ,  SCHNEEHAGE HANS HENNIG DIPL CH ,  LOEWENBERG GUSTAV DIPL ING ,  GRAU WERNER DIPL CHEM DR ,  MAHLER KARL DIPL ING DR ,  FALK ROLAND DIPL CHEM DR

IPC: C09D5/23 ,  G11B5/84 ,  G11B5/68 ,  B05D5/12

Abstract: Magnetic recording material is prepd. by intensive mixing of needle-like magnetic pigment and a carrier liq. comprising a synthetic organic binder and a dispersing agent to a paste and subsequent drying and granulating to a free flowing pigment mixt. The pigment mixt. is conventionally mixed with a synthetic organic binder, solvent and opt. other additives to form a dispersion which is coated thinly and evenly with simultaneous alignment of the needle-like pigment onto a support and dried. The recording material has improved packing in the binder and improved alignment. In a example, Fe2O3 powder was mixed with a polyesterurethane, dried, granulated, dispersed in a vinyl chloride copolymer soln. and coated onto a PET support.