US4393019A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of pressing reconstituted lignocellulosic materials
Assignee: United States Department of Agriculture
•
Filing: 1981-11-30
•
Granted: 1983-07-12
•
Expires: 2001-11-30
Abstract
Abstract A method of producing reconstituted wood boards in a conventional press by introducing saturated steam through apertured press platens into a partially-compressed mat, composed of lignocellulosic material and a thermosetting resin binder, under specified conditions of mat density. Use of saturated steam in this manner allows production of a reconstituted wood board with shorter total press time than usual and with a more efficient use of energy. In addition total press time can be further reduced by injecting a gaseous catalyst into the mat to speed the cure of the thermosetting resin binder.
Inventors
- 👤 Robert L. Geimer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:25
CPC Classifications
B; B27; B27N; B27N3/00; B27N3/08; B27N3/086
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
204 words
A method of producing a panel or the like from a mat formed of lignocellulosic material and a thermosetting resin binder in a press including a pair of heated platens wherein each platen has apertures opening to one surface thereof which is adjacent to the other platen, the improvement comprising the steps of: a. compressing the mat between the apertured platens to a density of less than about 26 to 28 pounds per cubic foot; b. introducing saturated steam into the mat through apertures of both apertured platens and simultaneously further compressing the mat between the apertured platens at a rate such that a mat centerline temperature of at least 212° F. is reached before the mat achieves a density of from 34 to 36 pounds per cubic foot and permitting the steam to escape through the edges of the mat; c. continue compressing the mat between the apertured platens while maintaining the steam flow, until a desired final mat density is reached; d. continue steaming the mat for a length of time sufficient for the mat to reach a maximum centerline temperature; and e. maintaining the mat between the apertured platens for a length of time sufficient to cure the thermosetting resin binder.
Claim 2
Independent Claim
204 words
A method of producing a panel or the like from a mat formed of lignocellulosic material and a thermosetting resin binder in a press including a pair of heated platens wherein each platen has apertures opening to one surface thereof which is adjacent to the other platen, the improvement comprising the steps of: a. compressing the mat between the apertured platens to a density of less than about 26 to 28 pounds per cubic foot; b. introducing saturated steam into the mat through apertures of both apertured platens and simultaneously further compressing the mat between the apertured platens at a rate such that a mat centerline temperature of at least 212° F. is reached before the mat achieves a density of from 34 to 36 pounds per cubic foot and permitting the steam to escape through the edges of the mat; c. continue compressing the mat between the apertured platens while maintaining the steam flow, until a desired final mat density is reached; d. continue steaming the mat for a length of time sufficient for the mat to reach a maximum centerline temperature; and e. maintaining the mat between the apertured platens for a length of time sufficient to cure the thermosetting resin binder.
Claim 3
Dependent Claim
27 words
The method of claim 1 wherein the length of time sufficient for the mat to reach the maximum core centerline temperature is from 2 to 60 seconds.
Claim 4
Dependent Claim
23 words
The method of claim 2 wherein the length of time sufficient to cure the thermosetting resin binder is from 10 to 180 seconds.
Claim 5
Dependent Claim
29 words
The method of claim 1, further comprising the step of: f. introducing a gaseous catalyst into the mat so as to accelerate the cure of the thermosetting resin binder.
Claim 6
Dependent Claim
21 words
A method in accordance with claim 1 wherein the initial mat moisture content is in the range of 4 to 18%.
Claim 7
Dependent Claim
41 words
A method in accordance with claim 1 wherein said platens are heated to a temperature of at least 250° F. at the time said mat is compressed to a density of less than about 26 to 28 pounds per cubic foot.
Claim 8
Dependent Claim
50 words
A method in accordance to claim 1 wherein the initial mat moisture content is about 8%, and wherein said platens are maintained at a temperature of approximately 375° F. at the time said mat is compressed to a density of less than about 26 to 28 pounds per cubic foot.
Claim 9
Dependent Claim
16 words
A method in accordance with claim 1 wherein said maximum centerline temperature is 240° F.-350° F.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-07-11 | 1987-01-10 | 1987-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-07-11 | 1991-01-10 | 1991-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-07-11 | 1995-01-10 | 1995-07-12 | $7700.00 | Window Closed / Lapsed |