Patent US3759687A successfully refreshed from Google Patents.
US3759687A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for manufacture of ureaformaldehyde fertilizer
Assignee: Individual
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Filing: 1971-04-30
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Granted: 1973-09-18
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Expires: 1991-04-30
Abstract
Abstract AN IMPROVED UREA-FORMALDEHYDE FERTILLIZER IS MADE BY REACTING AT 25* TO 45*C. FOR ONE TO FOUR HOURS AN ALKALINE AQUEOUS MIXTURE AT PH 10 TO 12 OF UREA AND PARAFORMALDEHYDE OR FORMALDEHYDE IN A UREA-TO-FORMALDEHYDE MOL RATIO OF ABOUT 1.25 TO ABOUT 0.83. THEN THE PH IS ADJUSTED TO BETWEEN 7 AND 8, AND THE PRODUCT IS HEATED TO BETWEEN 60* AND 80*C. FOR FROM 4 TO 25 HOURS. FINALLY, IN THE THIRD STAGE OF TREATMENT THE PRODUCT IS HEATED AT 100* TO 110*C. FOR FROM 1 TO 10 HOURS. THE RESULTING FERTILIZER IS EXCEPTIONALLY HIGH IN COLD-WATER-INSOLUBLE NITROGEN AND HAS A HIGH AVAILABILITY INDEX.
Inventors
- 👤 A Nobell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:44
CPC Classifications
C; C05; C05C; C05C9/00; C05C9/02
Claims Analysis
Total Claims: 0
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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) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |