Method for the production of glass fiber-reinforced gypsum sheets and gypsum board formed therefrom
First Claim
1. A method for preparing a cementitious construction sheet having reinforcing fibers dispersed therein, which comprises:
- (a) mixing together in a moving air current generated by an air blower a substantially dry water-settable calcium sulfate hemihydrate in finely particulate form with reinforcing glass fibers,(b) providing a foraminous moving surface,(c) depositing the mixture of calcium sulfate hemihydrate and glass fibers on said foraminous surface to form a sheet,(d) applying water over the sheet,(e) permitting the calcium sulfate hemihydrate to set, and(f) drying said sheet to remove any excess water.
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Accused Products
Abstract
A fiber-reinforced cementitious sheet is formed by first co-mixing in an air current reinforcing fibers such as glass fibers, and cementitious mineral materials in finely particulate form such as calcium sulfate hemihydrate, both in substantially dry form, depositing the mixture on a moving foraminous surface by means of the air current to form a sheet, applying water as by spraying in at least an amount which is stoichiometrically sufficient to hydrate the calcium sulfate hemihydrate to the dihydrate form and to provide the necessary degree of plasticity to the mixture, densifying the sheet by compression, and setting and drying the sheet. A pair of sheets may be utilized as face sheets and, prior to setting, combined with a core formed of for example a calcium sulfate hemihydrate slurry, and the sheets and core then set and dried to form a paper-free gypsum board having excellent strength, surface hardness, and fire-resistant properties.
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Citations
32 Claims
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1. A method for preparing a cementitious construction sheet having reinforcing fibers dispersed therein, which comprises:
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(a) mixing together in a moving air current generated by an air blower a substantially dry water-settable calcium sulfate hemihydrate in finely particulate form with reinforcing glass fibers, (b) providing a foraminous moving surface, (c) depositing the mixture of calcium sulfate hemihydrate and glass fibers on said foraminous surface to form a sheet, (d) applying water over the sheet, (e) permitting the calcium sulfate hemihydrate to set, and (f) drying said sheet to remove any excess water. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A cementitious construction sheet having reinforcing fibers dispersed therein, said sheet being the product formed by the method which comprises:
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(a) mixing together in a moving air current generated by an air blower a substantially dry water-settable calcium sulfate hemihydrate in finely particulate form with reinforcing glass fibers, (b) providing a foraminous moving surface, (c) depositing the mixture of calcium sulfate hemihydrate and glass fibers on said foraminous surface to form a sheet, (d) applying water over the sheet, (e) permitting the calcium sulfate hemihydrate to set, and (f) drying said sheet to remove any excess water. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32)
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30. A sheet according to claim 35, wherein said glass fibers are formed by chopping glass fiber strands and subsequently opening the chopped strands into individual fibers.
Specification