Gypsum-based acoustic panel
AssigneeKnauf Gips KG
InventorsChristian Balling, Michael Schneider
Life of this patent
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Abstract
A gypsum-based acoustic panel wherein in the panel includes a core layer of foamed gypsum, face side and back side layers of non-woven encasing the core layer, and the panel has an alphaw-value of between 0.4 and 0.7 and specific flow resistances of <15000 Pa s/m, methods for their preparation and their uses.
Claims14
A gypsum-based acoustic panel wherein in the panel comprises:
- a core layer of foamed gypsum;
- a first and a second cover sheet encasing the core layer;
- the panel has an alphaw-value of between 0.4 and 0.7 and a specific flow resistance of <15000 Pa s/m according to DIN EN 29053:1993;
- and
- the gypsum contains fibres in an amount of up to 1.0 to 2.0% by weight in relation to amount of gypsum.
A process for preparing a gypsum based acoustic panel having an alphaw-value of between 0.4 and 0.7 and a specific flow resistance of <15000 Pa s/m according to DIN EN 29053:1993 comprising of the following steps:
- I) providing beta-hemihydrate from a synthetic gypsum source;
- II) mixing the compound of I) with water to provide a slurry;
- III) mixing an active pore-forming compound comprising 0.1 to 5.0% by weight of an organic acid and 0.1 to 10.0% by weight of a carbonate with the compound of I) or the slurry of II) and/or mixing a surfactant-based foam with the slurry of II) to provide a foamed slurry;
- IV) applying the resulting foamed slurry to a first cover sheet, made of non-woven;
- V) applying a second cover sheet, made of non-woven, to the foamed slurry opposite to the side of the first cover sheet;
- VI) drying the product of VI) to obtain an acoustic panel;
- wherein the foamed slurry has a slump test value of between 155 and 190 mm and slurry-litre weight of between 520 and 580 g/l;
- wherein during and after the application of the foamed slurry no distributor roller is used;
- and
- the foamed slurry is distributed by vibration.
A process for preparing a gypsum based acoustic panel having an alphaw-value of between 0.4 and 0.7 and a specific flow resistance of <15000 Pa s/m according to DIN EN 29053:1993 comprising of the following steps:
- I) providing beta-hemihydrate from a synthetic gypsum source;
- II) mixing the compound of I) with water to provide a slurry;
- III) mixing an active pore-forming compound comprising 0.1 to 5.0% by weight of an organic acid and 0.1 to 10.0% by weight of a carbonate with the compound of I) or the slurry of II) and/or mixing a surfactant-based foam with the slurry of II) to provide a foamed slurry;
- IV) applying the resulting foamed slurry to a first cover sheet, made of non-woven;
- V) applying a second cover sheet, made of non-woven, to the foamed slurry opposite to the side of the first cover sheet;
- and
- VI) drying the product of VI) to obtain an acoustic panel;
- wherein the foam generation is started:
- i) before entering the mixer, with aid of surfactant;
- ii) upon entering of dry components, via a component screw, into the mixer;
- or i) before entering the mixer and upon entering of dry components into the mixer.
Dependencies are inferred from the claim text.