US4472455A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of magnetic recording media
Assignee: Emtec Magnetics GmbH
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Filing: 1983-12-23
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Granted: 1984-09-18
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Expires: 2003-12-23
Abstract
Abstract Magnetic recording media are produced by dispersing finely divided anisotropic magnetic material and conventional additives in a solution of a polymeric binder in an organic solvent, or in an aqueous dispersion of a polymeric binder, adding a polymer based on hydrophilic ethylenically unsaturated compounds to the magnetic dispersion, applying a layer of the dispersion to a non-magnetizable base, orienting the anisotropic magnetic material in a magentic field and drying the applied layer.
Inventors
- 👤 Albert Kohl
- 👤 Werner Balz
- 👤 Milena Melzer
- 👤 Norbert Schneider
- 👤 Eberhard Koester
- 👤 August Lehner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:02
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/7013; G11B5/702; G11B5/7021; G11B5/7022; G11B5/7023; G11B5/7028
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
210 words
A process for the production of a magnetic recording medium by dispersing finely divided anisotropic magnetic material and conventional additives in a solution of a polymeric binder in an organic solvent, or in an aqueous dispersion of a polymeric binder, applying a layer of the dispersion to a non-magnetizable base, orienting the anisotropic magnetic material by means of a magnetic field and drying the applied layer, wherein a polymer comprising (A) from 25 to 80% by weight of a polyether acrylate of the formula ##STR5## or a mixture of (I) and (II), where R 1 is hydrogen, alkyl of 1 to 25 carbon atoms or C 1 -C 12 -alkyl-substituted phenyl, R 2 is hydrogen or CH 3 , n is 1 to 30 and m is 0 to 25, (B) from 75 to 20% by weight of an ethylenically unsaturated C 3 -C 10 -carboxylic acid, or a mixture of such acids, and (C) from 0 to 40% by weight of an acrylate of the formula ##STR6## where R 3 is alkyl of 1 to 20 carbon atoms, R 4 is identical to R 3 or is ##STR7## where n is 1 to 20, and R 1 and R 2 have the above meanings, is added to the dispersion.
Claim 2
Dependent Claim
210 words
A process for the production of a magnetic recording medium by dispersing finely divided anisotropic magnetic material and conventional additives in a solution of a polymeric binder in an organic solvent, or in an aqueous dispersion of a polymeric binder, applying a layer of the dispersion to a non-magnetizable base, orienting the anisotropic magnetic material by means of a magnetic field and drying the applied layer, wherein a polymer comprising (A) from 25 to 80% by weight of a polyether acrylate of the formula ##STR5## or a mixture of (I) and (II), where R 1 is hydrogen, alkyl of 1 to 25 carbon atoms or C 1 -C 12 -alkyl-substituted phenyl, R 2 is hydrogen or CH 3 , n is 1 to 30 and m is 0 to 25, (B) from 75 to 20% by weight of an ethylenically unsaturated C 3 -C 10 -carboxylic acid, or a mixture of such acids, and (C) from 0 to 40% by weight of an acrylate of the formula ##STR6## where R 3 is alkyl of 1 to 20 carbon atoms, R 4 is identical to R 3 or is ##STR7## where n is 1 to 20, and R 1 and R 2 have the above meanings, is added to the dispersion.
Claim 3
Dependent Claim
21 words
A process as claimed in claim 1, wherein component (B) is acrylic acid or methacrylic acid, or a mixture of these.
Claim 4
Dependent Claim
27 words
A process as claimed in claim 1, wherein some or all of component (C) is replaced by other ethylenically unsaturated monomers of 2 to 20 carbon atoms.
Claim 5
Dependent Claim
15 words
A process as claimed in claim 1, wherein component (B) is present in salt form.
Claim 6
Dependent Claim
28 words
A process as claimed in claim 4, wherein the counter-ion used is ammonium or an amine having a boiling point below 100° C., or a mixture of these.
Claim 7
Dependent Claim
17 words
A process as claimed in claim 1 wherein the binder used in an aqueous anionic polyurethane ionomer.
Claim 8
Dependent Claim
29 words
A process as claimed in claim 1 wherein the binder used is a hydroxyl-containing polyurethane-urea having a molecular weight of from 500 to 3,000, in combination with a polyisocyanate.
Claim 9
Dependent Claim
18 words
A process as claimed in claim 1 wherein the binder consists partly or completely of a polyurethane elastomer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-18 | 1988-03-19 | 1988-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-18 | 1992-03-19 | 1992-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-18 | 1996-03-19 | 1996-09-18 | $7700.00 | Window Closed / Lapsed |