US4832928A
Expired / Lapsed
US
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Method for producing ammonium polyphosphate
Assignee: Carboline Co
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Filing: 1987-07-21
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Granted: 1989-05-23
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Expires: 2007-07-21
Abstract
Abstract A method of continuously producing ammonium polyphosphate by the reaction of urea and polyphosphoric acid, over a wide range of molecular weights, in a pre-mix slurry, under controlled temperature of about 315°+/-15° C. The slurry is reacted on a hot, continuously moving surface and forms ammonium polyphosphate in an ammonia atmosphere. Preferably, the pre-mixed slurry is added to a screw-type extruder, where the material comes in contact with the ammonia along the preheated moving surfaces of the extruder. The ammonium polyphosphate is scraped from the extrusion screw into a container with minimum handling. The material can be ground to a finer consistency if desired.
Inventors
- 👤 John A. Parker
- 👤 Rubin Feldman
- 👤 Robert L. Bryant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:24
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/16; C01B25/26; C01B25/38; C01B25/40; C01B25/405
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
102 words
A continuous process for the manufacture of ammonium polyphosphate, comprising a step of forming a mixture consisting essentially of one part of a polyphosphoric acid having an equivalent phosphoric acid content of at least about 110% and from about 0.5 to 3.0 parts of urea by weight, and a step of heating the reactants to a temperature of at least about 150° C. to ammoniate substantially all phosphorus atoms in the polyphosphoric acid, the heating step being carried out under an ammonia atmosphere in a heated extrusion device having an extruder screw which continuously forces the reaction mixture through a reaction barrel.
Claim 2
Dependent Claim
102 words
A continuous process for the manufacture of ammonium polyphosphate, comprising a step of forming a mixture consisting essentially of one part of a polyphosphoric acid having an equivalent phosphoric acid content of at least about 110% and from about 0.5 to 3.0 parts of urea by weight, and a step of heating the reactants to a temperature of at least about 150° C. to ammoniate substantially all phosphorus atoms in the polyphosphoric acid, the heating step being carried out under an ammonia atmosphere in a heated extrusion device having an extruder screw which continuously forces the reaction mixture through a reaction barrel.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein said polyphosphoric acid has an equivalent phosphoric acid content in the range of 110% to 120%.
Claim 4
Dependent Claim
29 words
The process of claim 1 wherein said heating step is carried out at least in part by internal heating caused by reaction of said polyphosphoric acid with said urea.
Claim 5
Dependent Claim
19 words
The process of claim 1 wherein said ammonium polyphosphate has a solubility of less than about 8% in water.
Claim 6
Dependent Claim
17 words
The process of claim 1 wherein said heated extrusion device provides continuous heating of said extruder screw.
Claim 7
Dependent Claim
22 words
The process of claim 1 wherein said ammonium polyphosphate has an equivalent phosphoric acid content of from about 115% to about 117%.
Claim 8
Dependent Claim
26 words
The process of claim 1 wherein said urea is mixed in a quantity of from about 0.8 to 1.2 parts by weight of the polyphosphoric acid.
Claim 9
Dependent Claim
30 words
The process of claim 1 wherein the reaction mixture is heated at a temperature and for a period sufficient to provide an ammonium polyphosphate which is less than 1% soluble.
Claim 10
Dependent Claim
88 words
A continuous process for the manufacture of ammonium polyphosphate, comprising continuously feeding to the barrel of a heated screw extruder one part of a polyphosphoric acid having an equivalent phosphoric acid content of at least about 115% and from about 0.8 to 1.2 parts of urea by weight, heating the reactants by a combination of heat created by reaction of the ammonium polyphosphate and heat applied to the heated screw extruder to a temperature above 150° C. under an ammonia atmosphere, and recovering ammonium polyphosphate from the extruder.
Claim 11
Dependent Claim
88 words
A continuous process for the manufacture of ammonium polyphosphate, comprising continuously feeding to the barrel of a heated screw extruder one part of a polyphosphoric acid having an equivalent phosphoric acid content of at least about 115% and from about 0.8 to 1.2 parts of urea by weight, heating the reactants by a combination of heat created by reaction of the ammonium polyphosphate and heat applied to the heated screw extruder to a temperature above 150° C. under an ammonia atmosphere, and recovering ammonium polyphosphate from the extruder.
Claim 12
Dependent Claim
17 words
The process of claim 9 wherein said heated extrusion device provides continuous heating of said extruder screw.
Claim 13
Dependent Claim
22 words
The process of claim 9 wherein said ammonium polyphosphate has an equivalent phosphoric acid content of from about 115% to about 117%.
Claim 14
Dependent Claim
30 words
The process of claim 9 wherein the reaction mixture is heated at a temperature and for a period sufficient to provide an ammonium polyphosphate which is less than 1% soluble.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-22 | 1992-11-21 | 1993-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-22 | 1996-11-21 | 1997-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-22 | 2000-11-21 | 2001-05-23 | $7700.00 | Window Closed / Lapsed |