Claims
- 1. A process for the production of magnetic recording carriers by the preparation of a dispersion consisting essentially of finely divided magnetic pigments, a dispersing agent and a solution of a polymeric binder in an organic solvent and an isocyanate-compound as cross-linking agent for the polymeric binder and application of the dispersion to a non-magnetizable layer support followed by orientation of the magnetic pigment by means of a magnetic field and drying of the applied layer, wherein the dispersing agent used consists of at least one compound containing one reactive group which produces a firm bond to the magnetic pigment and at least one other group reactive to the NCO-groups of a difunctional or higher functional isocyanate consisting of a compound corresponding to the general formula ##STR11## wherein ##STR12## n=1 or 2 W=H or an optionally branched alkyl group having 1 to 30 carbon atoms,
- B=a straight chained, optionally branched alkyl group optionally containing hetero atoms, a cycloaliphatic group, or a cycloaliphatic-aromatic group, ##STR13## wherein m=1-20,
- R.sub.3 =H, or CH.sub.3, or ##STR14## wherein V=alkyl with 1-30 carbon atoms,
- O=1, 2, or 3,
- q=0 or 1
- O+q=3 ##STR15## X, Y=H, C.sub.1 -C.sub.30 -alkyl or C.sub.1 -C.sub.30 -O-alkyl and X=Y or X.noteq.Y.
- 2. Process for the production of magnetic recording carriers according to claim 1, characterised in that the dispersing agent is used in a quantity of from 0.5 to 10% by weight, based on the magnetic pigment, and in that the difunctional or higher functional isocyanate is used in a quantity of from 0.2 to 30% by weight, based on the binder.
- 3. A process for the production of magnetic recording carriers according to claim 1 wherein the group of the dispersing agent reactive to the NCO-groups of the isocyanate is NH-- or OH--.
- 4. A process for the production of magnetic recording carriers according to claim 1 wherein the polymeric binder contains NH-- or OH-groups as groups reactive to the NCO-groups of the isocyanate.
- 5. A process for the production of a magnetic recording carrier which comprises the steps of
- preparing a composition comprising, finely divided magnetic pigments,
- a solution of a polymeric binder containing reactive groups in an organic solvent,
- a cross-linking agent consisting of a difunctional or higher functional isocyanate, and
- a dispersing agent consisting of at least one compound containing
- at least one reactive group capable of bonding to the magnetic pigment and at least one other group reactive to the NCO groups of the isocyanate,
- said dispersing agent corresponding to the general formula ##STR16## wherein ##STR17## n=1 or 2 W=H or an optionally branched alkyl group having 1 to 30 carbon atoms,
- B=a straight chained, optionally branched alkyl group optionally containing hetero atoms, a cycloaliphatic group, or a cycloaliphatic-aromatic group, ##STR18## wherein m=1-20,
- R.sub.3 =H, or CH.sub.3, or ##STR19## wherein V=alkyl with 1-30 carbon atoms,
- O=1,2, or 3,
- q=0 or 1
- O+q=3 ##STR20## X, Y=H, C.sub.1 -C.sub.30 -alkyl or C.sub.1 -C.sub.30 -O-alkyl and X=Y or X.noteq.Y,
- firmly bonding the dispersing agent to the magnetic pigments,
- linking the dispersing agent to the binder by means of the isocyanate,
- applying the composition to a non-magnetic layer support,
- subsequently orienting the magnetic pigment by means of a magnetic field, and
- drying the applied layer to form a magnetic recording layer.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3629606 |
Aug 1986 |
DEX |
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Parent Case Info
This application is a continuation, of application Ser. No. 86,851, filed Aug. 19, 1987, now abandoned.
US Referenced Citations (6)
Continuations (1)
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Number |
Date |
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Parent |
86851 |
Aug 1987 |
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