Patent US4252910A successfully refreshed from Google Patents.
US4320171A
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Magnetic recording media containing elastomeric polyurethane binders in the magnetic coating
Assignee: Emtec Magnetics GmbH
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Filing: 1980-05-19
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Granted: 1982-03-16
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Expires: 2000-05-19
Abstract
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).
Inventors
- 👤 Herbert Motz
- 👤 August Lehner
- 👤 Heinrich Hartmann
- 👤 Rudolf Bachmann
- 👤 Hans-Joerg Hartmann
- 👤 Harald Frischmann
- 👤 Roland Falk
- 👤 Joachim Hack
- 👤 Milan Velic
- 👤 Helmut Kopke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:29
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/65; C08G18/66; C08G18/6633; C08G18/6637; C08G18/664; C08G18/6644; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31565; Y10T428/31591; Y10T428/31609
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
210 words
A magnetic recording medium comprising a non-magnetic base and, applied thereto, a firmly adhering magnetic coating consisting essentially of a dispersion of a magnetic pigment in a binder which contains at least 50 percent by weight of a thermoplastic polyurethane which is soluble in tetrahydrofuran, is free from isocyanate groups and has been made by reaction of (A) 1 mole of a hydroxy-containing polyester having a molecular weight of from 700 to 2,500, wherein said hydroxyl-containing polyester is formed by esterification of aliphatic dicarboxylic acids of 4 to 12 carbon atoms, carboxylic acid esters of 1 to 4 carbon atoms in the alcohol radical, carboxylic acid anhydrides or carboxylic acid chlorides with aliphatic glycols of 2 to 12 carbon atoms which may contain ether groups, in the presence as a chain extender of (B) from 0.3 to 3 moles of a linear aliphatic diol containing from 2 to 10 carbon atoms and (C) from 0.05 to 0.4 moles of a triol containing from 3 to 10 carbon atoms and (D) from 1.35 to 4.7 moles of an aromatic diisocyanate containing from 6 to 30 carbon atoms, the amount of isocyanate groups present in the reaction being approximately equivalent to the amount of hydroxy groups in the components A to C.
Claim 2
Dependent Claim
210 words
A magnetic recording medium comprising a non-magnetic base and, applied thereto, a firmly adhering magnetic coating consisting essentially of a dispersion of a magnetic pigment in a binder which contains at least 50 percent by weight of a thermoplastic polyurethane which is soluble in tetrahydrofuran, is free from isocyanate groups and has been made by reaction of (A) 1 mole of a hydroxy-containing polyester having a molecular weight of from 700 to 2,500, wherein said hydroxyl-containing polyester is formed by esterification of aliphatic dicarboxylic acids of 4 to 12 carbon atoms, carboxylic acid esters of 1 to 4 carbon atoms in the alcohol radical, carboxylic acid anhydrides or carboxylic acid chlorides with aliphatic glycols of 2 to 12 carbon atoms which may contain ether groups, in the presence as a chain extender of (B) from 0.3 to 3 moles of a linear aliphatic diol containing from 2 to 10 carbon atoms and (C) from 0.05 to 0.4 moles of a triol containing from 3 to 10 carbon atoms and (D) from 1.35 to 4.7 moles of an aromatic diisocyanate containing from 6 to 30 carbon atoms, the amount of isocyanate groups present in the reaction being approximately equivalent to the amount of hydroxy groups in the components A to C.
Claim 3
Dependent Claim
33 words
The magnetic recording medium of claim 1, wherein the reaction to produce the polyurethane has been carried out in an organic solvent which does not react with the diisocyanate under the reaction conditions.
Claim 4
Dependent Claim
33 words
The magnetic recording medium of claim 1, wherein the polyurethanes have a softening point greater than 125° C. and have a hardness, measured according to DIN 53,157, of from 18 to 35 seconds.
Claim 5
Dependent Claim
15 words
The magnetic recording medium of claim 1, wherein the binder consists solely of the polyurethanes.
Claim 6
Dependent Claim
42 words
The magnetic recording medium of claim 1, wherein (A) is a polyester formed from adipic acid and butane diol, chain extender (B) is butane diol, triol (C) is selected from the group consisting of trimethylolpropane and glycerol and diisocyanate (D) is diphenylmethane-4,4'-diisocyanate.
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) | 1985-03-15 | 1985-09-14 | 1986-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-15 | 1989-09-14 | 1990-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-15 | 1993-09-14 | 1994-03-16 | $7700.00 | Window Closed / Lapsed |