Ready-mixed setting type joint compound
AssigneeUnited States Gypsum Company
InventorsTherese A. Espinoza, Charles J. Miller, Richard B. Stevens
Life of this patent
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Abstract
A cementitious composition of the setting type which can be kept in a ready-mixed state and which can be caused to set and harden upon introduction of an accelerator with reproducibility and set time predictability. The cementitious base composition contains calcium sulfate hemihydrate as a principal filler material and certain non-calcium bearing phosphate additives which prevent setting action in the presence of water. An accelerator, such as zinc sulfate, may be added to the ready-mixed, cementitious composition to initiate the setting action, or the ready-mixed cementitious composition can be used as a drying type joint compound without the addition of an accelerator.
Claims18
A ready-mixed, cementitious composition which forms a setting type joint compound when mixed with an accelerator for the reaction of calcium sulfate hemihydrate with water to form set gypsum, said composition comprising from about 20 to about 99 weight percent (based on total solids used to form the composition) of a calcium sulfate hemihydrate filler, a calcium carbonate filler, from about 1 to about 10 weight percent (based on total solids used to form the composition) of a sepiolite, bentonite, or attapulgus clay, from about 0.1 to about 10 weight percent (based on total solids used to form the composition) of a non-calcium bearing phosphate set retarder which maintains said cementitious composition in an unset state for at least 175 days, a binder, a thickener and water.
A ready-mixed, cementitious composition comprising from about 20 to about 99 weight percent (based on total solids used to form the composition) of a calcium sulfate hemihydrate filler, from about 1 to about 10 weight percent (based on total solids used to form the composition) of a sepiolite, bentonite, or attapulgus clay, from about 0.1 to about 10 weight percent (based on total solids used to form the composition) of a non-calcium bearing phosphate set retarder which maintains said cementitious composition in an unset state for at least 175 days, and water.
A joint compound system comprising separately packaged components for preparing a setting type joint compound wherein the components are:
- A. a cementitious composition in ready-mixed form containing from about 20 to about 99 weight percent (based on total solids used to form the composition) of a calcium sulfate hemihydrate filler, a latex binder, from about 1 to about 10 weight percent (based on total solids used to form the composition) of a sepiolite, bentonite, or attapulgus clay, from about 0.1 to about 10 weight percent (based on total solids used to form the composition) of a non-calcium bearing phosphate set retarder which maintains said cementitious composition in an unset state for at least 175 days, and water, and
- B. an accelerator component comprising a compound having a cation with a log K value greater than that of calcium ions, and which, when mixed with said cementitious composition, permits said cementitious composition to set.
Dependencies are inferred from the claim text.