Method for Constructing Composite Building Boards Using Dissolvable Films
AssigneeCertainTeed Gypsum, Inc.
InventorsRobert Joseph Hauber, Gerald D. Boydston
Life of this patent
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Abstract
Disclosed are building board manufacturing techniques that minimize the build-up of slurry on associated forming equipment and also produce panels with enhanced physical properties. The methods involve applying a dissolvable film laminate to one or more fiber mats at the outset of the forming process. In the un-dissolved state, the film acts as a containment envelope for the gypsum slurry and any free floating glass fibers. During subsequent curing, the film is dissolved by vaporized water. In its dissolved state, the film is liquefied and coats the fibers of the underlying mat. This results in a building board with improved physical properties.
Claims10
A method for the manufacture of composite building boards formed from first and second mats of non-woven, randomly aligned glass fibers and an intermediate gypsum core, the method comprising the following steps:
- adhering a PVA film to a lower surface of the first mat, the PVA film being completely dissolvable in the presence of heat and water;
- pouring a layer of gypsum slurry over an upper surface of the first mat, the slurry penetrating the first mat but being retained by the PVA film;
- applying the second mat to the gypsum slurry layer, the first and second mats and intermediate gypsum slurry forming a composite panel;
- passing the composite panel along a forming belt, wherein the PVA film functions as a containment envelope to prevent the accumulation of gypsum slurry on the forming belt;
- cutting the composite panel into composite building boards of desired lengths;
- flipping the composite building board, whereby PVA film the is exposed and the second mat faces the forming belt;
- heating the composite building boards in a series of dryers to cure the gypsum slurry, wherein during the curing process entrained water within the gypsum slurry is vaporized and passes through the exposed PVA film;
- dissolving the PVA film via heat from the dryers and the vaporized water, the dissolved film flowing over and adhering to the fibers of the first mat to thereby enhance the physical properties of the composite building boards.
A method for the manufacture of composite building board comprising the following steps:
- applying a dissolvable film to a surface of a porous mat;
- pouring a layer of wet slurry over the porous mat, the wet slurry penetrating the porous mat but being retained by the film;
- passing the porous mat along a belt, wherein the film prevents the accumulation of wet slurry on the belt;
- heating the porous mat and wet slurry, wherein the wet slurry is dried and the film is dissolved.
A method for the manufacture of building board comprising the following steps:
- applying a dissolvable film to a surface of a porous mat;
- pouring a layer of wet slurry over the porous mat, the wet slurry penetrating the porous mat but being retained by the film;
- passing the porous mat along a belt, wherein the film prevents the accumulation of wet slurry on the belt;
- dissolving the film, whereby the dissolved film enhances the physical properties of the building board.
Dependencies are inferred from the claim text.