Method and apparatus for producing a multilayer cementitious product
AssigneeBPB Limited
InventorsWinfried Johannes Josef Spikermann, Kane Ian Ironside
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Abstract
Gypsum plasterboard is produced by combining calcium sulphate hemihydrate (stucco) with water to form an aqueous slurry. Uncalcined gypsum having a specific surface area below 0.3 m2/g is added to the slurry and the slurry is discharged onto a support so as to form a sheet of gypsum plasterboard.
Claims17
A method of preparing an acoustic gypsum wallboard having improved sound blocking properties, the method comprising steps of:
- a) combining calcium sulfate hemihydrate with water to form an aqueous slurry;
- b) adding an inert filler of uncalcined calcium sulfate dihydrate particles of desulphogypsum (DSG) to the slurry within a range of 20% to 25% w:w of the calcium sulfate hemihydrate, the dihydrate particles having a specific surface area of 0.1-0.3 m2/g and a particle size distribution of 0.1-1000 microns;
- c) discharging the resulting slurry after step b) onto a support;
- and
- d) setting the discharged slurry so as to form a sheet of gypsum wallboard having a water gauge reduction with respect to a wallboard containing no uncalcined gypsum,
- wherein the inert filler provides improved acoustic properties to the wallboard.
A cementitious composition for producing an acoustic gypsum wallboard having improved sound blocking properties, the composition comprising a mixture of calcium sulfate hemihydrate, water, and an inert filler of uncalcined calcium sulfate dihydrate particles of desulphogypsum (DSG) in a range of 20% to 25% w:w of the calcium sulfate hemihydrate, the dihydrate particles having a specific surface area of 0.1-0.3 m2/g and a particle size distribution of 0.1-1000 microns, wherein the composition is discharged as a slurry onto a support and then set into a sheet of gypsum wallboard having a water gauge reduction with respect to a wallboard containing no uncalcined gypsum, and wherein the inert filler provides improved acoustic properties to the wallboard.
Dependencies are inferred from the claim text.