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US3935343A
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Molten salt method of producing fire resistant wood articles
Assignee: WOOD FIBER INDUSTRIES Inc 1 SOUTH WACKER DR CHICAGO ILL 60606 A CORP OF
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Filing: 1974-02-21
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Granted: 1976-01-27
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Expires: 1994-02-21
Abstract
Abstract Hardboard and other wood articles are made fire resistant by immersing the wood in a molten ammonium phosphate salt batn, preferably monoammonium phosphate.
Inventors
- 👤 Harold W. Nuttall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:51
CPC Classifications
B; B27; B27K; B27K3/00; B27K3/16; B27K3/20; B27K3/02; B27K3/0242; B27K3/0278; B27K3/08; B27K3/166; B27K5/00; B27K5/04; C; C09; C09K; C09K21/00; C09K21/02; C09K21/04; B27K2240/00; B27K2240/30; Y; Y10; Y10S; Y10S428/00; Y10S428/92; Y10S428/921
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
38 words
A method for imparting fire resistance to wood articles within a period of 3 minutes which comprises immersing the wood article in molten ammonium phosphate substantially free of water under a pressure of at least about 10 p.s.i.g.
Claim 2
Independent Claim
38 words
A method for imparting fire resistance to wood articles within a period of 3 minutes which comprises immersing the wood article in molten ammonium phosphate substantially free of water under a pressure of at least about 10 p.s.i.g.
Claim 3
Dependent Claim
24 words
The method of claim 1 in which the ammonium phosphate is selected from the group consisting of monoammonium phosphate, diammonium phosphate and mixtures thereof.
Claim 4
Dependent Claim
18 words
The method of claim 1 in which the molten phosphate is maintained at a pH of about 1.5-6.
Claim 5
Dependent Claim
31 words
The method of claim 1 in which the molten phosphate is monoammonium phosphate; and the molten phosphate is maintained at a pH of about 1.5-6 by the addition of diammonium phosphate.
Claim 6
Dependent Claim
12 words
The method of claim 3 in which the pH is about 3-4.
Claim 7
Dependent Claim
13 words
The method of claim 1 in which the pressure is about 10-100 p.s.i.g.
Claim 8
Dependent Claim
23 words
The method of claim 1 including the steps of removing the wood article from the molten salt and washing the surface with water.
Claim 9
Independent Claim
57 words
A method for imparting fire resistance to hardboard within a period of three minutes which comprises immersing the hardboard in a molten ammonium phosphate salt bath substantially free of water; subjecting the immersed hardboard to a pressure of at least 10 p.s.i.g.; removing the hardboard from the molten salt bath; and washing the treated hardboard with water.
Claim 10
Independent Claim
57 words
A method for imparting fire resistance to hardboard within a period of three minutes which comprises immersing the hardboard in a molten ammonium phosphate salt bath substantially free of water; subjecting the immersed hardboard to a pressure of at least 10 p.s.i.g.; removing the hardboard from the molten salt bath; and washing the treated hardboard with water.
Claim 11
Dependent Claim
20 words
The method of claim 8 in which the treated hardboard is dipped in water and then allowed to air dry.
Claim 12
Dependent Claim
24 words
The method of claim 8 in which the molten salt is selected from the group consisting of monoammonium phosphate, diammonium phosphate and mixtures thereof.
Claim 13
Dependent Claim
12 words
The method of claim 8 in which the pH is about 1.5-6.
Claim 14
Dependent Claim
12 words
The method of claim 11 in which the pH is about 3.5.
Claim 15
Dependent Claim
13 words
The method of claim 8 in which the pressure is about 10-100 p.s.i.g.
Claim 16
Dependent Claim
13 words
The method of claim 8 in which the pressure is about 60-80 p.s.i.g.
Claim 17
Dependent Claim
22 words
The method of claim 1, wherein the initial temperature of said molten ammonium phosphate is in the range of about 380°-400° F.
Claim 18
Dependent Claim
23 words
The method of claim 8, wherein the initial temperature of said molten ammonium phosphate salt is in the range of about 380°-400° F.
References Cited (Backward Citations)
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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) | 1979-01-26 | 1979-07-28 | 1980-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-26 | 1983-07-28 | 1984-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-26 | 1987-07-28 | 1988-01-27 | $7700.00 | Window Closed / Lapsed |