US3681137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording media
Assignee: TDK Corp
•
Filing: 1971-03-26
•
Granted: 1972-08-01
•
Expires: 1991-03-26
Abstract
Abstract MAGNETIC RECORDING MEDIA MAY BE PREPARED BY MIXING A MAGNETIC POWDER WITH A BINDER WHICH IS OBTAINED BY ADDING 10-50% BY WEIGHT OF BUTYL CELLULOSE ACETATE RESIN TO A MIXTURE OF 40-80% BY WEIGHT OF URETHANE PREPOLYMER AND 20-60% BY WEIGHT OF URETHANE ELASTOMER AND BY ADDING FURTHER, AS A HARDENER, AN AROMATIC POLYAMINE IN A STOICHIOMETRIC AMOUNT WITH RESPECT TO THE -NCO GROUPS IN THE URETHANE PREPOLYMER.
Inventors
- 👤 Yasuro Nagazono
- 👤 Terufumi Kamijo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31573; Y10T428/31576; Y10T428/31609
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |