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US4686145A
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Magnetic recording medium, a process for preparing a magnetic recording medium and a binder composition therefor
Assignee: Sumika Covestro Urethane Co Ltd
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Filing: 1986-02-19
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Granted: 1987-08-11
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Expires: 2006-02-19
Abstract
Abstract A novel magnetic recording medium consisting of a base material, magnetic particles and a specific polyurethane-based binder containing incorporated sulphonate groups, a process for preparing such a magnetic recording medium which comprises coating a base material with a coating material comprising (i) an organic solvent, (ii) a polyurethane binder containing chemically incorporated sulphonate groups and (iii) magnetic particles and the most preferred binder composition therefor comprising a hexandiol-(1,6)-polycarbonate-based polyurethane.
Inventors
- 👤 Masaru Honda
- 👤 Takanori Chiba
- 👤 Toshiaki Imokawa
- 👤 Yoshito Harada
- 👤 Katsumi Nagayasu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:13
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/0804; C08G18/0819; C08G18/0828; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31609
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
156 words
A binder composition comprising a polyurethane resin obtained by reacting (a) a polyisocyanate component with (b) a polyol component comprising (i) a hexane diol-(1,6)-polycarbonate having terminal hydroxyl groups and having a molecular weight of from 400 to 10,000, (ii) a sulfonate-free diol chain extender which has a molecular weight of from 62 to 399, and (iii) a diol containing chemically bonded sulphonate groups of the formula ##STR2## wherein A and B are the same or different divalent aliphatic hydrocarbon radicals having from 1 to 6 carbon atoms; R is hydrogen, alkyl having from 1 to 4 carbon atoms or phenyl; M is an alkali metal atom; m and n are 0 or an integer up to 30; o and p are 0 or 1, and q is 0, 1 or 2; and wherein the amount of reactant (iii) is an amount such that the resulting polyurethane contains from 10-200 equivalents of sulphonate groups per 1,000 kilograms.
Claim 2
Dependent Claim
156 words
A binder composition comprising a polyurethane resin obtained by reacting (a) a polyisocyanate component with (b) a polyol component comprising (i) a hexane diol-(1,6)-polycarbonate having terminal hydroxyl groups and having a molecular weight of from 400 to 10,000, (ii) a sulfonate-free diol chain extender which has a molecular weight of from 62 to 399, and (iii) a diol containing chemically bonded sulphonate groups of the formula ##STR2## wherein A and B are the same or different divalent aliphatic hydrocarbon radicals having from 1 to 6 carbon atoms; R is hydrogen, alkyl having from 1 to 4 carbon atoms or phenyl; M is an alkali metal atom; m and n are 0 or an integer up to 30; o and p are 0 or 1, and q is 0, 1 or 2; and wherein the amount of reactant (iii) is an amount such that the resulting polyurethane contains from 10-200 equivalents of sulphonate groups per 1,000 kilograms.
Claim 3
Dependent Claim
29 words
In an improved magnetic recording medium containing a base material, magnetic particles and a binder, the improvement comprises said binder being the binder composition in accordance with claim 1.
Claim 4
Dependent Claim
46 words
A process for preparing a magnetic recording medium which comprises coating a base material with a coating material comprising (i) an organic solvent, (II) a polyurethane binder and (III) magnetic particles, characterized in that the polyurethane binder is a binder composition in accordance with claim 1.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |