公开(公告)号：DE2501902A1

公开(公告)日：1976-07-22

申请号：DE2501902

申请日：1975-01-18

Applicant: BASF AG

Inventor： PISTER PHILIPP ,  OHLINGER MANFRED DIPL CHEM DR ,  STRITZINGER HEINZ DIPL ING ,  HARTMANN JOB-WERNER DIPL CHEM ,  WETTSTEIN EUGEN

IPC: C09C1/24 ,  C09C1/34 ,  C09C3/00 ,  G11B5/706 ,  C09C3/10 ,  G11B5/68

Abstract: Process for improving the dispersibility of needle-shaped magnet oxide pigments used for magnetic recording carriers, by washing the pigment in an aq. medium, filtering and drying. The washing water contains, by wt. 0.1-10% of a polymerised, organic, water-soluble or at least water-miscible, surfactant, and is used at 30-95 degrees C. The wash water pref. contains 4-8% of the surfactant and is used at 85-95 degrees C. the pref. surfactants being an melamine-formaldehyde condensn. product and/or a phthalic acid-polyol reaction product and/or a ricinoleic acid-maleic anhydride product, with mol.wt. 300-400. The pigment is pref. gamma Fe2O3. The magnetic recording tape obtd. has reducted direct current noise and lower harmonic distortion.

公开(公告)号：DE2461936A1

公开(公告)日：1976-07-08

申请号：DE2461936

申请日：1974-12-31

Applicant: BASF AG

Inventor： PISTER PHILIPP ,  BUETTNER FRANZ ,  OHLINGER MANFRED DIPL CHEM DR ,  STRITZINGER HEINZ DIPL ING ,  HARTMANN JOB-WERNER DIPL CHEM ,  SCHNEIDER WALTER ,  HAMMON FRITZ

IPC: C09D5/23 ,  C09D7/12 ,  G11B5/716 ,  G11B5/68 ,  B05D5/12 ,  H01F10/02

公开(公告)号：DE2352958A1

公开(公告)日：1975-04-30

申请号：DE2352958

申请日：1973-10-23

Applicant: BASF AG

Inventor： PISTER PHILIPP ,  WOLLNICK MANFRED DIPL-ING DR ,  STRITZINGER HEINZ DIPL-ING ,  HARTMANN JOB-WERNER DIPL-CHEM

IPC: C09D5/23 ,  G11B5/702 ,  G11B5/71 ,  G11B5/72

Abstract: Flexible magnetogram carrier esp for endless cassettes consists of a flexible plastic support film that is provided with a bonding layer coated on one side with (I) a magnetic layer consisting of a finely divided magnetic pigment in (II) an org. binder, and, on the side opposite to I, with (III) a lubricating layer consisting of a mixt of (IV) 50-90 wt. % of a lubricant, and (V) 50-10 wt. % of an org. binder. V is either (a) a copolymer of 75-95 esp. 75-85 wt. % vinyl chloride and 25-5 esp. 25-15 wt. % of an ester of a 1-3C aliphatic alcohol with a 3-6C olefinically unsatd carboxylic acid, or (b) a vinylformal polymer contg. at least 65 wt. % vinylformal gps. II consists of polymer (b) when copolymer (a) is used in layer III, or of copolymer (a) when polymer (b) is used in layer III. The carrier has good winding and running properties, satisfactory electro-acoustic value and low head abrasion.