US3894306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Memorex Corp
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Filing: 1973-11-07
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Granted: 1975-07-15
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Expires: 1993-11-07
Abstract
Abstract A magnetic recording medium comprising a plastic base and an adherent coating comprising acicular gamma ferric oxide having an appreciable content of ferrous iron dispersed in a resinous binder consisting essentially of a polyurethane resin, a copolymer of vinylidene chloride and acrylonitrile, a diimide, a divalent lead salt, a free radical chain reaction inhibitor and a dispersant is described.
Inventors
- 👤 Frederic J Sischka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:18
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/7013; G11B5/702; G11B5/7021; G11B5/7022; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31562; Y10T428/31565; Y10T428/31573; Y10T428/3158; Y10T428/31583; Y10T428/31609; Y10T428/31721
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
106 words
A MAGNETIC RECORDING MEDIUM COMPRISING A PLASTIC BASE AND AN ADHERENT COATING, SAID COATING COMPRISING AN ACICULAR GAMMA FERRIC OXIDE HAVING AN APPRECIABLE CONTENT OF FERROUS IRON DISPERSED IN A RESINOUS BINDER CONSISTING ESSENTIALLY OF: A. A POLYURETHANE RESIN PREPARED BY REACTING P-P''DIPHENYLMETHANE DIISOCYANATE, ADIPIC ACID AND BUTANE DIOL 1-4 IN PROPORTIONS SUCH THAT ALL OF THE ISOCYANATE GROUPS HAVE REACTED TO GIVE A SUBSTANTIALLY UNREACTIVE POLYMER, B. A COPOLYMER OF VINYLIDENE CHLORIDE AND ACRYLONITRILE AND CONTAINING IN EXCESS OF 50 PERCENT BY WEIGHT OF VINYLIDENE CHLORIDE C. A DIIMIDE SELECTED FROM THE GROUP CONSISTING OF HN = C = NH AND DIMIDES HAVING THE FORMULA
Claim 2
Dependent Claim
106 words
A MAGNETIC RECORDING MEDIUM COMPRISING A PLASTIC BASE AND AN ADHERENT COATING, SAID COATING COMPRISING AN ACICULAR GAMMA FERRIC OXIDE HAVING AN APPRECIABLE CONTENT OF FERROUS IRON DISPERSED IN A RESINOUS BINDER CONSISTING ESSENTIALLY OF: A. A POLYURETHANE RESIN PREPARED BY REACTING P-P''DIPHENYLMETHANE DIISOCYANATE, ADIPIC ACID AND BUTANE DIOL 1-4 IN PROPORTIONS SUCH THAT ALL OF THE ISOCYANATE GROUPS HAVE REACTED TO GIVE A SUBSTANTIALLY UNREACTIVE POLYMER, B. A COPOLYMER OF VINYLIDENE CHLORIDE AND ACRYLONITRILE AND CONTAINING IN EXCESS OF 50 PERCENT BY WEIGHT OF VINYLIDENE CHLORIDE C. A DIIMIDE SELECTED FROM THE GROUP CONSISTING OF HN = C = NH AND DIMIDES HAVING THE FORMULA
Claim 3
Dependent Claim
37 words
The adherent coating defined in claIm 1 containing, in addition, diphenyl mercuric ammonium propionate and butoxyethyl stearate in amounts sufficient to constitute from 0.01 to 0.03% and from 0.08 to 0.15% respectively of the total adherent coating.
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) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |