公开(公告)号：DE4222015A1

公开(公告)日：1994-01-05

申请号：DE4222015

申请日：1992-07-04

Applicant: BASF MAGNETICS GMBH

Inventor： CREDNER HANS-HEINRICH DR ,  SCHROEER WOLF-DIETER DR ,  VASS ATTILA DR ,  SCHMIDT JUERGEN ,  POLLUK CORNELIA DR

IPC: C08G18/40 ,  C09D5/23 ,  G11B5/702

Abstract: The novel feature in a magnetic recording material having a magnetic layer comprising a finely-divided magnetic pigment and a crosslinker in a binder mixt. contg. (A) a binder of Tg below 10 deg.C. and (B) a binder of TG above 30 deg.C. is that the binder mixt. also contains (C) an OH-contg. oligourethane or polyesteroligourethane. USE/ADVANTAGE - The material can be used as a video tape. Use of this three-component binder gives a low viscosity magnetic dispersion which can be spread at high speed on the carrier tape in stripe-free condition to give a prod. with good electro-acoustic properties (in partic. low modulation roar), good stability in a VHS E-120 cassette to harsh conditions, (e.g. 40 deg.C./85% RH), low drop-out and a softening pt. higher than that for conventional recording materials. Adhesion drop in tape coiling is reduced.

公开(公告)号：DE4313514A1

公开(公告)日：1993-11-04

申请号：DE4313514

申请日：1993-04-24

Applicant: BASF MAGNETICS GMBH

Inventor： VASS ATTILA DR ,  SCHROEER WOLF-DIETER DR ,  CREDNER HANS-HEINRICH DR ,  FISCHER HILDEGARD

IPC: G11B5/70 ,  G11B5/712 ,  G11B5/702

Abstract: Magnetic recording medium comprises, on a non-magnetic substrate, a magnetic dispersion(s) comprising (i) a pigment dispersed in a polymeric binder; and (ii) a codispersant comprising quat. ammonium cpd., guanidine, piperidine, alkylated or ethoxylated amine, ethanolic KOH soln., metal alkoxylate, Grignard cpd. or metal hydride. The dispersant pref. comprises a diamine having tert. substn., a polyamine (mixt.), sodium borohydride, sodium boronate, the Li or K cpd. thereof, lithium aluminium hydride or lithium alanate, LiH or NaH or KH in oil, LiH suspension, sodium amide suspension in toluene, LiNH2, potassium tri-sec-butylborohydride or K selectride. The codispersant comprises tetra-n-alkylammonium hydroxide, pentaalkylguanidine, pentaisoalkylguanidine, piperidine or ethanolic KOH soln., and is added in amt. of 0.15-4 wt.%, based on the pigment.

公开(公告)号：DE4433931A1

公开(公告)日：1995-04-06

申请号：DE4433931

申请日：1994-09-23

Applicant: BASF MAGNETICS GMBH

Inventor： BRODT GREGOR DR ,  VASS ATTILA DR ,  LOCH WERNER DR ,  LEHNER AUGUST ,  LENZ WERNER DR ,  SCHNEIDER NORBERT

IPC: C08G18/10 ,  C08G18/62 ,  C08G18/78 ,  C09D5/23 ,  C09D175/00 ,  C09D175/04 ,  G11B5/702 ,  C08G18/83

Abstract: The invention concerns magnetic recording media consisting of a nonmagnetic base material and, firmly adherent thereto, at least one magnetisable layer based on a magnetic material dispersed in a binder mixture which contains at least one hydroxyl-containing, preferably low molecular weight polyurea urethane and a polyurethane urea (meth)acrylate, characterised in that the polyurethane urea (meth)acrylate is obtained by reacting a poly(meth)acrylate having up to 2 OH end groups per mole and a molecular weight between 200 and 50000 with a mixture of aliphatic polyisocyanates having an average functionality of 3.0 to 6.0 NCO groups per mole and consisting of 0.1 to 10% by weight of a diisocyanate, 30 to 80% by weight of a triisocyanate, and 20 to 60% by weight of an isocyanate having a functionality of 4 to 10, with the proviso that 1.2 to 3.0 NCO groups are reacted per OH group and the remaining NCO groups are converted with polyfunctional amines or a mixture of various polyfunctional amines in substituted urea end groups.

公开(公告)号：DE4214273A1

公开(公告)日：1993-11-04

申请号：DE4214273

申请日：1992-04-30

Applicant: BASF MAGNETICS GMBH

Inventor： VASS ATTILA DR ,  SCHROEER WOLF-DIETER DR ,  KOBER HEINRICH DR

IPC: G11B5/70 ,  G11B5/842 ,  G11B5/84

Abstract: Prepn. of magnetic recording material consisting of a nonmagnetic support and at least one coating of a dispersion of a fine magnetic pigment in a polymeric binder. The binder is soluble in organic solvents and a dispersing agent is used. The amount of dispersing agent is calculated so that the ESA measurement (electroacoustic sound amplitude) has an absolute value of at least 10 mPa. sxmx volt-1, measured at 1 MHz in a dispersion of 2 wt. % magnetic pigment in 100 wt. % solvent. The ESA value is not increased by the addition of further dispersing agent. ADVANTAGE - Reproducible improvement in dispersion stability, lower flow limit and improved mechanical and magnetic properties of the prod.

公开(公告)号：DE4434768A1

公开(公告)日：1996-04-04

申请号：DE4434768

申请日：1994-09-29

Applicant: BASF MAGNETICS GMBH

Inventor： LEISTNER WILFRIED ,  LITZEL WOLFGANG ,  VASS ATTILA DR

IPC: B01F23/57 ,  C01G37/027 ,  C08J3/215 ,  C09D5/23 ,  G11B5/842 ,  C09D17/00 ,  C08K3/22 ,  B01F3/14

Abstract: A multi-stage process for the prodn. of a magnetic dispersion contg. magnetic pigments finely dispersed in a polymeric binder comprises: (a) stirring 100 pts.wt. of magnetic pigments, 0.5-9 pts.wt. of dispersant and opt. finely divided non-magnetic pigments with sufficient solvent to give a solids concn. of 40-60%, (b) finely dispersing the mixt. in several passes through one or more agitator mills, with addn. of a first part of the binder mixed with solvent in the last part of this stage, and (c) adding the second part of the binder, also dissolved in solvent, and opt. other additives in a high-speed mixer.

公开(公告)号：DE59106529D1

公开(公告)日：1995-10-26

申请号：DE59106529

申请日：1991-10-19

Applicant: BASF MAGNETICS GMBH

Inventor： SCHROER WOLF-DIETER DR ,  VASS ATTILA DR ,  SAUTER JUERGEN ,  SCHMIDT JUERGEN ,  KUNTZ GUENTHER

IPC: G11B5/708 ,  C09D5/23 ,  G11B5/70 ,  G11B5/702 ,  G11B5/712 ,  G11B5/714 ,  G11B5/73 ,  G11B5/842

Abstract: A magnetic dispersion, consisting of fine particles of iron powder or iron alloy powder having a BET value of more than 35 m /g, which powder is dispersed in a polymeric binder and an organic solvent and has markedly improved filterability, is obtained by using certain low-molecular phosphoric acid esters of the general formula I or II in combination with a dispersion-active compound which contains at least one polar group capable of absorption on the magnetic pigment. The polar group of the dispersion-active compound can be an acidic or alkaline or amphoteric group, a group which is capable of forming hydrogen bonds, or a polarisable group. The dispersion-active compound can be a polycondensate, a polyaddition product or a copolymer, which can also be used in the magnetic dispersion in combination with other conventional polymeric binders.

公开(公告)号：DE4138267A1

公开(公告)日：1993-05-27

申请号：DE4138267

申请日：1991-11-21

Applicant: BASF MAGNETICS GMBH

Inventor： SCHELBLE JOSEF DR ,  CREDNER HANS-HEINRICH DR ,  SCHMIDT JUERGEN ,  SCHROEER WOLF-DIETER DR ,  VASS ATTILA DR

IPC: G11B5/706 ,  G11B5/71 ,  G11B5/86

Abstract: Magnetic tape (MT) for thermomagnetic copying contains a magnetic pigment (I-M) with Curie temp. TC1 and copy tape (CT) a magnetic pigment (I-C) with Curie temp. TC2, both finely dispersed in polymeric binder. For copying, CT is heated to a temp. above TC2 but below TC1 and then cooled in close contact with MT. MT and/or CT contains fatty acid and/or fatty ester with a butyl palmitate (II) fraction as lubricant. The novelty is that the (II) content of MT and/or CT is max. 0.15 g/100g (I). Pref. (I-M) consists of metal (alloy) powder with a coercivity of min. 100 kA/m and TC1 greater than 300 deg.C; and (I-C) or CrO2 with a coercivity of min. 40 kA/m and TC2 ca. 130 deg.C. USE/ADVANTAGE - The system is useful for video purposes. The tapes are suitable for high speed copying. MT still has satisfactory running properties after several thousand passes and transfers the information to TC without loss or distortion, even after prolonged use.