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US 6,632,262 B2Granted
Controlled release urea-formaldehyde liquid fertilizer resins
AssigneeGeorgia-Pacific Resins, Inc.
InventorKurt D. Gabrielson
Life of this patent
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Abstract
A controlled release urea-formaldehyde liquid resin having a nitrogen level of at least 28 wt % and its method of manufacture. The controlled release urea-formaldehyde resin is useful as a fertilizer.
Claims18
A urea-formaldehyde resin prepared by the method comprising:
- combining formaldehyde, urea, and ammonia in a basic solution at a formaldehyde/urea/ammonia ratio of about 0.6-1.0/1/0.25-0.35;
- heating the solution to about 85 to about 95° C., and holding while maintaining pH between about 7.5 and 10.5 for about 45 to 120 minutes;
- cooling the solution to less than about 50° C., and adjusting the pH to about 9.5 to about 10.5;
- wherein the nitrogen content of the resin is at least about 28 wt % based on 100% resin solids, the triazone content of the resin is 14 to 20 wt %, and about 50-60 wt % of the nitrogen is controlled release and about 40-50 wt % of the nitrogen is quick release.
1 more element
A method of producing a urea-formaldehyde liquid resin comprising:
- 1) combining formaldehyde, urea, and ammonia in a basic solution at a formaldehyde/urea/ammonia ratio of about 0.6-1/1/0.25-0.35;
- 2) heating the solution to about 80° C. to about 95° C., and holding while maintaining pH of at least 7 for at least 45 minutes;
- and
- 30 cooling the solution to less than about 50° C., and adjusting the pH to about 9.5 to about 10.5;
- wherein the nitrogen content of the urea-formaldehyde resin is at least about 28 wt % based on 100% resin solids and about 50 wt % to about 60 wt % of the nitrogen is controlled release and about 40 wt % to about 50 wt % of the nitrogen is quick release.
2 more elements
Dependencies are inferred from the claim text.