Patent US3935341A successfully refreshed from Google Patents.
US3935341A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for rendering wood resistant to fire
Assignee: Kanamark International Ltd
•
Filing: 1973-12-07
•
Granted: 1976-01-27
•
Expires: 1993-12-07
Abstract
Abstract Wood can be rendered fire resistant by impregnating the wood with a solution of a monomer, such as a phenol, and a fire-inhibiting salt, drying the wood and thereafter treating the wood with a solution of a second monomer, such as formaldehyde, polymerizable with the first monomer. Heating to dryness causes polymerization of the monomers. The fire resistant properties of wood treated this way are not affected by exposure to moisture. Prior to the first impregnation, after the first impregnation and after treatment with the second monomer the wood being treated is dried to a moisture content below about 4%.
Inventors
- 👤 Karl-Otto Sorensen
- 👤 Jorgen Sondergaard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:24
CPC Classifications
B; B27; B27K; B27K3/00; B27K3/02; B27K3/0207; B27K3/0214; B27K3/0278; B27K3/15; B27K5/00; B27K5/001; B27K5/04; C; C08; C08L; C08L97/00; C08L97/02; B27K2240/00; B27K2240/30; C08L61/00; C08L61/04; C08L61/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
119 words
A method for rendering wood resistant to fire which comprises: heating the wood to dry the same to a mositure content of below about 4%; impregnating the heated, dried wood, while still hot, with an aqueous solution containing from about 7 to about 70% by weight of a formaldehyde-reactive monomer, said solution having a temperature of at least 80°C.; heating the formaldehyde-reactive monomer-impregnated wood to dry the same to a moisture content of below about 4%; impregnating the dry, formaldehyde-reactive monomer-containing wood with a stoichiometric excess of formaldehyde; and heating the now twice impregnated wood to effect a condensation reaction between the formaldehyde-reactive monomer and the formaldehyde, and to dry the wood to a moisture content of about 4%.
Claim 2
Independent Claim
119 words
A method for rendering wood resistant to fire which comprises: heating the wood to dry the same to a mositure content of below about 4%; impregnating the heated, dried wood, while still hot, with an aqueous solution containing from about 7 to about 70% by weight of a formaldehyde-reactive monomer, said solution having a temperature of at least 80°C.; heating the formaldehyde-reactive monomer-impregnated wood to dry the same to a moisture content of below about 4%; impregnating the dry, formaldehyde-reactive monomer-containing wood with a stoichiometric excess of formaldehyde; and heating the now twice impregnated wood to effect a condensation reaction between the formaldehyde-reactive monomer and the formaldehyde, and to dry the wood to a moisture content of about 4%.
Claim 3
Dependent Claim
17 words
A method according to claim 1 in which the formaldehyde is present as an aqueous solution thereof.
Claim 4
Dependent Claim
23 words
A method according to claim 1 in which the wood is treated with a fire-inhibiting compound prior to the formaldehyde-reactive monomer impregnation step.
Claim 5
Dependent Claim
45 words
A method according to claim 2 in which the formaldehyde-reactive monomer solution contains up to about 30% by weight of a fire-inhibiting compound, and in which the wood contains about 50 kilograms of the formaldehyde-reactive monomer per cubic meter after the first mentioned impregnation step.
References Cited (Backward Citations)
US949671A
Cited
US2123152A
Cited
US2661341A
Cited
US2632742A
Cited
US3062678A
Cited
US3243140A
Cited
US3320213A
Cited
US3336959A
Cited
US3519476A
Cited
US3547687A
Cited
US3701743A
Cited
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 |