Method of pressing reconstituted lignocellulosic materials
AssigneeThe United States of America as represented by the Secretary of Agriculture
InventorRobert L. Geimer
Life of this patent
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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.
Claims8
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.degree. 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.
Dependencies are inferred from the claim text.