公开(公告)号：JPH10283630A

公开(公告)日：1998-10-23

申请号：JP8609098

申请日：1998-03-31

Applicant: EMTEC MAGNETICS GMBH

Inventor： GOETZ KLAUS ,  JAKUSCH HELMUT DR ,  LOCH WERNER DR ,  HOFFMANN ERICH ,  GOTTMANN HANS-GEORG ,  JENOR HANS-JOACHIM ,  VOIT JOHANN DR

IPC: G11B5/706 ,  G11B5/716

Abstract: PROBLEM TO BE SOLVED: To obtain a magnetic recording medium with which the audible linear distortions in association with a Dolby noise suppression system are eliminated, the production is simplified and the output levels at low frequencies and high frequencies are improved. SOLUTION: This magnetic recording medium consists of a nonmagnetic base 1 and at least two magnetic layers 2, 3 formed on this nonmagnetic base 1. These two layers 2, 3 contain magnetizable metal oxides as magnetic pigments. These magnetic pigments consist of cobalt-contg. FeOx (1.33

公开(公告)号：DE19626824A1

公开(公告)日：1998-01-08

申请号：DE19626824

申请日：1996-07-03

Applicant: EMTEC MAGNETICS GMBH

Inventor： WEINGART FRANZ DR ,  BURKHARDT UWE ,  BAUER STEPHAN DR ,  REICH WOLFGANG DR ,  KOHL ALBERT ,  KRESS RIA DR ,  TRAUB HANSJOERG DR ,  LOCH WERNER DR

IPC: C08G18/83 ,  G11B5/702 ,  C08L75/04 ,  C08L75/06 ,  C08L75/08 ,  C08L75/12 ,  C09D175/04

Abstract: A magnetic recording material contains a layer comprising a magnetic pigment and a polyurethane binder (I) prepared by reacting an isocyanate (II) with a chain extender (V).(II) are (a) prepolymers prepared by reacting (A1) a polyvalent alcohol (III) containing more than one hydroxyl group per molecule capable of reacting with (II), with (A2) an aromatic or aliphatic polyvalent isocyanate (IV), or (b) compounds (IV). The ratio of reactive hydroxyl groups in (III) to the isocyanate groups in (IV) is less than 1. (V) are prepared by reacting (a) a polyvalent alcohol (VI) with either (b1) a compound (VII) containing an epoxy group and an additional functional group which is reactive with alcohols, forming a compound (VIII) which is reacted with an alpha,beta-olefinic unsaturated carboxylic acid (IX) to form a compound (X), or (b2) a compound (IX) to form a compound (X), and then (c) reacting (X) with an amine (XI) containing at least one prim. amino group which can react with olefinic bond in (IX). The sum of reactive amino and hydroxyl groups in (V) is greater than the number of isocyanate groups in (II).

公开(公告)号：DE19644347C2

公开(公告)日：1999-08-12

申请号：DE19644347

申请日：1996-10-25

Applicant: EMTEC MAGNETICS GMBH

Inventor： WUENSCH THOMAS DR ,  KRESS RIA DR ,  LOCH WERNER DR ,  LEHNER AUGUST ,  KOHL ALBERT ,  SCHNEIDER NORBERT ,  BURKHARDT UWE

IPC: C08K3/08 ,  C08G18/10 ,  C08G18/32 ,  C08G18/38 ,  C08G18/64 ,  C08G18/72 ,  C08K3/22 ,  C08L75/00 ,  C08L75/04 ,  C09D5/23 ,  C09D175/00 ,  C09D175/04 ,  G11B5/702 ,  C08G18/30 ,  C09D17/00

Abstract: Hydroxyl-containing polyurethanes I are composed essentially of a) a diisocyanate of 6 to 30 carbon atoms (component II), b) a component III comprising alpha ) an aliphatic diol of 2 to 20 carbon atoms or beta ) an aromatic-aliphatic or aromatic-cycloaliphatic diol of 8 to 30 carbon atoms having nonphenolic hydroxyl groups as hydroxyl groups of the diol and c) a polyhydric alcohol having at least 3 hydroxyl groups, 3 to 18 carbon atoms and nonphenolic hydroxyl groups as hydroxyl groups of the alcohol (component IV), the amounts of components II to IV being such that the total number of nonphenolic hydroxyl groups is from 1.1 to 5.0 per isocyanate group of II. The polyurethanes can be used as binders or binder components for pigment-containing coatings, in particular for the production of magnetic recording materials.

公开(公告)号：DE19714161A1

公开(公告)日：1998-10-08

申请号：DE19714161

申请日：1997-04-05

Applicant: EMTEC MAGNETICS GMBH

Inventor： GOETZ KLAUS DIPL ING ,  GOTTMANN HANS-GEORG ,  HOFFMANN ERICH ,  JAKUSCH HELMUT DR ,  JENOR HANS-JOACHIM ,  LOCH WERNER DR ,  VOIT JOHANN DR

IPC: G11B5/706 ,  G11B5/716

Abstract: In a magnetic recording carrier having two magnetic layers, in which the upper layer contains a cobalt-containing FeOx (x = 1.33 to 1.5) magnetic pigment with a higher BET value than that of the lower layer magnetic pigment, the thicknesses of the upper and lower layers (3, 2) are 3.1-5 mu m and 1.1-3 mu m, respectively. Preferably, the coercive field strengths of the upper and lower layers are 55-60 kA/m and 50-55 kA/m respectively or, when the magnetic pigment of the lower layer is CrO2, the coercive field strength of the lower layer is 40-55 kA/m.