公开(公告)号：DE2459766A1

公开(公告)日：1976-07-01

申请号：DE2459766

申请日：1974-12-18

Applicant: BASF AG

Inventor： SCHOENAFINGER EDUARD DR ,  DEIGNER PAUL DR ,  KOESTER EBERHARD DR ,  OHLINGER MANFRED DR ,  SCHAEFER DIETER DR ,  STUMPFI WERNER DR

IPC: G11B5/842 ,  C09C1/34 ,  C09C3/12 ,  G11B5/706 ,  G11B5/708 ,  G11B5/62

Abstract: Chromium dioxide magnetic pigments are stabilised against loss of magnetic properties by (a) treating an alcoholic or aq. alcoholic suspension of the pigment with a hydrolysis prod. of a silane RnSi(CR')4-n where R = 3-18 C aliphatic org. gp., R' = 1-8C aliphatic org. gp. and n=1-3, such that it remains at least partially on the surface of the pigment after separating the pigment from the medium, and (b) drying the treated pigment at ca 50-200 degrees C. gives pigments useful in making magnetic tapes etc. which are resistant to loss of magnetic properties under advers (hot and moist) climatic conditions; gives better protection than known processes in which e.g. a thin chromium oxide layer or an inorg. metal phosphate layer is deposited on the pigment surface. The pigments also have improved dispersibility and processability.

公开(公告)号：AT34246T

公开(公告)日：1988-05-15

申请号：AT84101845

申请日：1981-09-21

Applicant: BASF AG

Inventor： STUMPFI WERNER DR ,  ENGEL FRIEDRICH ,  FITTERER HORST ,  KREIMES NORBERT ,  PFEFFERKORN DIETMAR ,  SCHAEFFER NORBERT ,  SCHMIDTS KURT

IPC: G11B23/04

公开(公告)号：DE2538792A1

公开(公告)日：1977-03-17

申请号：DE2538792

申请日：1975-09-01

Applicant: BASF AG

Inventor： SCHOENAFINGER EDUARD DR ,  DEIGNER PAUL DR ,  KOESTER EBERHARD DR ,  OHLINGER MANFRED DR ,  SCHAEFER DIETER DR ,  STUMPFI WERNER DR ,  AMORT JUERGEN DR ,  SEILER CLAUS-DIETRICH DR ,  NESTLER HEINZ DR ,  AMBROS OTTO DR

IPC: C09C1/34 ,  C09C3/12 ,  G11B5/706 ,  G11B5/62

Abstract: Stabilisation of magnetic dioxide pigments for prepn. of magnetic registering matls. is effected by (a) suspending the pigment in an aqs. and/or alcoholic medium (b) treating the suspended pigment with a silane of formula RnSi(OR')4-n (where R is a 1-18C org. gp; R' is a 1-8C aliphatic org. gp.; and n is 1-3), or with a hydrolysis prod. of this silane, so that least partly hydrolysed silane is situated on the surface of the pigment, after the latter has been separated from the medium, and (c) drying the separated pigment at 50-200 degrees C. Retain their good magnetic properties, even under unfavourable climatic, e.g. hot and humid conditions. The pigments are also easily dispersed and worked.

公开(公告)号：DE3176740D1

公开(公告)日：1988-06-16

申请号：DE3176740

申请日：1981-09-21

Applicant: BASF AG

Inventor： STUMPFI WERNER DR ,  ENGEL FRIEDRICH ,  FITTERER HORST ,  KREIMES NORBERT ,  PFEFFERKORN DIETMAR ,  SCHAEFFER NORBERT ,  SCHMIDTS KURT

IPC: G11B23/04

公开(公告)号：DE3168164D1

公开(公告)日：1985-02-21

申请号：DE3168164

申请日：1981-09-21

Applicant: BASF AG

Inventor： STUMPFI WERNER DR ,  BETTINGER GUENTER ,  ENGEL FRIEDRICH ,  FITTERER HORST ,  KREIMES NORBERT ,  PFEFFERKORN DIETMAR ,  SCHAEFFER NORBERT ,  SCHMIDTS KURT

IPC: G11B15/30 ,  G11B23/04

Abstract: The invention relates to a hub for magnetic tape cassettes, especially compact cassettes, and to magnetic tape cassettes possessing such hubs. In a first embodiment, spring means are provided on the inner periphery of the hub and exert radial pressures on the drive spindle, the spring means consisting, for example, of sprung teeth. In a further embodiment, the teeth have a spring rate of from about 1 P/mm to 40 P/mm. In another embodiment, the hub consists of an inner part and an outer part which can be coupled to one another and between which there is some play after coupling. A large number of specific examples of hubs are given to show possible shapes and arrangements of the teeth, and to show the types of material that can be used. In an advantageous embodiment, the inner part of the two-part hub can also be made a part of the drive spindle on the recorder, which inner part can be coupled with the outer part when the drive spindle enters the cassette.