公开(公告)号：DE2753694A1

公开(公告)日：1979-06-07

申请号：DE2753694

申请日：1977-12-02

Applicant: BASF AG

Inventor： MOTZ HERBERT DIPL ING DR ,  LEHNER AUGUST ING GRAD ,  HARTMANN HEINRICH DIPL CHEM DR ,  BACHMANN RUDOLF DIPL CHEM DR ,  HARTMANN HANS-JOERG DIPL ING D ,  FRISCHMANN HARALD DR ,  FALK ROLAND DIPL CHEM DR ,  HACK JOACHIM DIPL CHEM ,  VELIC MILAN DIPL ING DR

IPC: C08G18/66 ,  C09D5/23 ,  G11B5/70 ,  G11B5/702 ,  G11B5/68

Abstract: Magnetic recording media comprising a non-magnetic base and, applied thereto, a firmly adhering magnetic coating based on a finely divided magnetic pigment dispersed in a binder which contains at least 50 percent by weight of a special polyurethane elastomer, namely a thermoplastic polyurethane which is soluble in tetrahydrofuran, is free from isocyanate groups and has been manufactured from (A) 1 mole of a hydroxyl-containing polyester having a molecular weight of from 700 to 2,500, (B) from 0.3 to 3 moles of a linear aliphatic diol of 2 to 10 carbon atoms, (C) from 0.05 to 0.4 mole of a triol of 3 to 10 carbon atoms, and (D) from 1.35 to 4.7 moles of a diisocyanate of 6 to 30 carbon atoms, the amount of NCO groups being approximately equivalent to the amount of OH groups of the sum of components (A) to (C).

公开(公告)号：DE2749757A1

公开(公告)日：1979-05-10

申请号：DE2749757

申请日：1977-11-07

Applicant: BASF AG

Inventor： VAETH GUENTER ,  OHLINGER MANFRED DIPL CHEM DR ,  HARTMANN HANS-JOERG DIPL ING D ,  VELIC MILAN DIPL ING DR ,  MUENZNER WULF DIPL ING DR

IPC: G11B5/706 ,  G11B5/712 ,  G11B5/68 ,  C09C1/34

Abstract: Magnetic recording material has a non-magnetic substrate with a firmly adhering magnetic coating of acicular ferromagnetic CrO2 finely dispersed in an organic polymeric binder and additives. Before incorporation in the binder, the CrO2 is suspended in an aq. soln. of the Fe(II) salt and a reducing agent, the Fe)II) ions are pptd. on the CrO2 as Fe(OH)2 by addn. of water-soluble hydroxide or carbonate and this Fe(OH)2 is then converted to an oxide deposit contg. Fe(III) by treatment with a gaseous or water-miscible oxidant. The oxide deposit pref. consists of goethite and/or lepidocrocite or magnetite. The Fe oxide deposit improves the stability and mechanical properties of the CrO2 under unfavourable climatic conditions.

公开(公告)号：DE2407713A1

公开(公告)日：1975-09-04

申请号：DE2407713

申请日：1974-02-18

Applicant: BASF AG

Inventor： TRIMBORN WERNER DIPL CHEM DR ,  DEMMLER KURT DIPL CHEM DR ,  VELIC MILAN DIPL ING DR

IPC: C08F299/04 ,  C08F283/00 ,  C09D3/68