US3240621A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High viscosity dispersions of magnetic pigments
Assignee: Dictaphone Corp
•
Filing: 1960-11-14
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Granted: 1966-03-15
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Expires: 1980-11-14
Abstract
No abstract record available.
Inventors
- 👤 Jr Guiles Flower
- 👤 Albert L Tufano
- 👤 Frederick W Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:44
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/84; G11B5/842; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
69 words
THE METHOD OF MAKING A MAGNETIC RECORDING MEDIUM WHICH COMPRISES APPLYING TO A SUBSTRATE A THIN COATING OF NON-NEWTONIAL DISPERSION COMPRISING FINELYDIVIDED ACIULAR MAGNETIC IRON OXIDE PARTICLES AND A RESIN BINDER IN A VOLATILE SOLVENT THEREFOR, SAID DISPERSION HAVING AN APPARENT VISCOSITY OF AT LEAST 50,000 CENTIPOISES AT 75*-80*F., AND SAID COATING BEING SUBSTANTIALLY FREE OF AGGLOMERATES OF SAID MAGNETIC PARTICLES, AND THEN REMOVING SAID SOLVENT FROM SAID COATING.
Claim 2
Dependent Claim
29 words
THE METHOD ACCORDING TO CLAIM 4 WHEREIN SAID IRON OXIDE PARTICLES ARE ORIENTED BY PASSING SAID SUBSTRATE, AFTER COATING BUT BEFORE REMOVAL OF SAID SOLVENT, THROUGH A MAGNETIC FIELD.
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) | 1969-03-14 | 1969-09-13 | 1970-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-03-14 | 1973-09-13 | 1974-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-03-14 | 1977-09-13 | 1978-03-15 | $7700.00 | Window Closed / Lapsed |