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Patent US4411683A successfully refreshed from Google Patents.
US4411683A
Expired / Lapsed
US
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Process of preparing solid controlled release fertilizer composition
Assignee: OMS Investments Inc
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Filing: 1981-07-30
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Granted: 1983-10-25
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Expires: 2001-07-30
Abstract
Abstract Process of preparing a solid controlled release urea-formaldehyde fertilizer composition comprising preparing an aqueous mixture of urea, formaldehyde and ammonia, heating the mixture, acidifying the mixture to initiate methylene urea polymerization and heating to complete methylene urea polymerization and dry the reaction products. The process is carried out under conditions such that the majority of polymeric nitrogen present in the final product consists of short chain methylene urea polymers selected from the group consisting of methylene diurea, dimethylene triurea and mixtures thereof.
Inventors
- 👤 Harvey M. Goertz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:41
CPC Classifications
C; C05; C05C; C05C9/00; C05C9/02; Y; Y10; Y10S; Y10S71/00; Y10S71/903; Y10S71/904
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
166 words
A process of preparing a solid controlled release urea-formaldehyde fertilizer composition comprising preparing an aqueous mixture of urea, formaldehyde and ammonia, the molar ratio of urea to formaldehyde ranging from 1 to 3, the molar ratio of ammonia to formaldehyde ranging from 0.05 to 1.00, heating said mixture to a temperature of from 140° to 190° F. at an alkaline pH, the heating being stopped prior to the formation methylene urea polymers, said reaction producing a mixture of methylol ureas and an ammonia intermediate reaction product, acidifying said reaction mixture with from 0.1 to 8% by weight of the mixture of an acid to initiate methylene urea polymerization and heating said reaction mixture to a temperature of from 180° to 320° F. for a time sufficient to complete said methylene urea polymerization and dry said reaction product, the majority of polymeric nitrogen present in said product consisting of short chain methylene urea polymers selected from the group consisting of methylene diurea, dimethylene triurea and mixtures thereof.
Claim 2
Dependent Claim
166 words
A process of preparing a solid controlled release urea-formaldehyde fertilizer composition comprising preparing an aqueous mixture of urea, formaldehyde and ammonia, the molar ratio of urea to formaldehyde ranging from 1 to 3, the molar ratio of ammonia to formaldehyde ranging from 0.05 to 1.00, heating said mixture to a temperature of from 140° to 190° F. at an alkaline pH, the heating being stopped prior to the formation methylene urea polymers, said reaction producing a mixture of methylol ureas and an ammonia intermediate reaction product, acidifying said reaction mixture with from 0.1 to 8% by weight of the mixture of an acid to initiate methylene urea polymerization and heating said reaction mixture to a temperature of from 180° to 320° F. for a time sufficient to complete said methylene urea polymerization and dry said reaction product, the majority of polymeric nitrogen present in said product consisting of short chain methylene urea polymers selected from the group consisting of methylene diurea, dimethylene triurea and mixtures thereof.
Claim 3
Dependent Claim
19 words
The process of claim 1 in which the molar ratio of urea to formaldehyde is from 1.2 to 2.5.
Claim 4
Dependent Claim
19 words
The process of claim 1 in which the molar ratio of ammonia to formaldehyde is from 0.10 to 0.75.
Claim 5
Dependent Claim
20 words
The process of claim 1 in which the temperature of said first heating step is from 165° to 185° F.
Claim 6
Dependent Claim
20 words
The process of claim 1 in which the temperature of said second heating step is from 220° to 320° F.
Claim 7
Dependent Claim
28 words
The process of claim 1 in which the mixture of methylol urea and ammonia intermediate reaction product are sprayed onto an inert carrier prior to acidifying the mixture.
Claim 8
Dependent Claim
13 words
The process of claim 6 in which the inert carrier is expanded vermiculite.
Claim 9
Dependent Claim
27 words
The process of claim 6 in which the second heating step is at a temperature of from 220° to 320° F. for from 15 to 35 minutes.
Claim 10
Dependent Claim
39 words
The process of claim 1 in which, subsequent to acidifying but prior to said second heating step, said reaction mixture is spread into a layer which, upon heating, coalesces into a physically stable material which can be easily handled.
Claim 11
Dependent Claim
26 words
The process of claim 1 in which the mixture of methylol urea and ammonia intermediate reaction product are slurried with an inert bulking agent before acidifying.
Claim 12
Dependent Claim
31 words
The process of claim 1 in which a source of potassium and phosphorus nutrient are added to the intermediate reaction mixture prior to acidifying and prior to said second heating step.
Claim 13
Dependent Claim
25 words
The process of claim 1 in which the reaction mixture is acidified with from 0.5 to 3% by weight of the mixture of an acid.
Claim 14
Dependent Claim
18 words
The process of claim 1 in which the aqueous mixture contains less than 15% by weight of water.
Claim 15
Dependent Claim
19 words
The process of claim 1 in which the acidified reaction mixture is heated for from 15 to 35 minutes.
References Cited (Backward Citations)
US3129091A
Cited
US3677736A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-24 | 1987-04-25 | 1987-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-24 | 1991-04-25 | 1991-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-24 | 1995-04-25 | 1995-10-25 | $7700.00 | Window Closed / Lapsed |