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AssigneeBASF SE
InventorsRonald A. Lee, David T. Durocher, Sridhar Gopalkrishnan Iyer, Richard J. Romanek, Eli Stav, Karen Fey
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A slurry for manufacturing gypsum board comprises calcined gypsum, water, a foaming agent, and a coalescing agent. The foaming agent imparts a plurality of bubbles in the slurry. Typically, a foam is pre-generated with the foaming agent and the foam is used to form the slurry such that the foam imparts the plurality of bubbles in the slurry. The coalescing agent coalesces the plurality of bubbles imparted by the foam. Typically, the coalescing agent coalesces a plurality of small and partially joined bubbles imparted by the foam to create larger and more discrete bubbles. A gypsum board and method of forming the slurry and the gypsum board are also disclosed. The gypsum board comprises a gypsum layer formed from the slurry. The gypsum layer defines a plurality of bubbles dispersed therein, which are imparted by the foam and coalescing agent of the slurry.
A gypsum board comprising a cover sheet and a gypsum layer disposed on said cover sheet, said gypsum layer defining a plurality of bubbles dispersed therein and comprising the reaction product of:
A method of forming a gypsum board comprising a cover sheet and a gypsum layer disposed on the cover sheet, the gypsum layer defining a plurality of bubbles dispersed therein and comprising the reaction product of calcined gypsum and water, wherein an exothermic reaction occurs between the calcined gypsum and water, with the reaction product having a temperature ranging from an initial temperature (T1) to a peak temperature (T2) during formation in the presence of a foaming agent comprising a surfactant for creating a foam to impart a plurality of bubbles in the reaction product and a coalescing agent comprising an ethylene oxide-propylene oxide (EO/PO) block copolymer and/or a reverse EO/PO block copolymer, with the coalescing agent having a cloud point (TCP) of from about 16.0 to about 60.0° C. according to ASTM D2024 and that is between the initial temperature (T1) and the peak temperature (T2) of the reaction product, such that the coalescing agent coalesces the plurality of bubbles imparted by the foam thereby establishing the plurality of bubbles in the gypsum layer, said method comprising the steps of:
Dependencies are inferred from the claim text.