The present invention is directed to a construction chemical composition for the preparation of gypsum articles, said construction chemical composition comprising fine calcium sulfate and a dispersant being a polyarylether. Further the present invention is directed to a process for preparing said construction chemical composition as well as an article comprising said construction chemical composition.

Method of making foamed gypsum slurry having 15 to 90 volume percent gas bubbles including: passing first slurry including water and on dry basis 50 to 98 wt. % calcium sulfate hemihydrate, 1 to 50 wt. % calcium carbonate, and 0.1 to 10 wt. % cellulose thickener via a first hose to a Wye connector conduit first inlet opening at Rate C and passing alum solution via a second hose to a second inlet opening of the conduit at Rate D to create combined mixed stream passing from the conduit to a static mixer for mixing for Time 3 to activate at least a portion of the calcium carbonate and alum to generate CO.sub.2 and create the foamed gypsum slurry; transferring the slurry from the mixer to a cavity between two wall boards via a third hose. Allowing the slurry in the cavity to expand, harden and dry.

Method of making foamed gypsum slurry having 15 to 90 volume percent gas bubbles including: passing first slurry including water and on dry basis 50 to 98 wt. % calcium sulfate hemihydrate, 1 to 50 wt. % calcium carbonate, and 0.1 to 10 wt. % cellulose thickener via a first hose to a Wye connector conduit first inlet opening at Rate C and passing alum solution via a second hose to a second inlet opening of the conduit at Rate D to create combined mixed stream passing from the conduit to a static mixer for mixing for Time 3 to activate at least a portion of the calcium carbonate and alum to generate CO.sub.2 and create the foamed gypsum slurry; transferring the slurry from the mixer to a cavity between two wall boards via a third hose. Allowing the slurry in the cavity to expand, harden and dry.

An open cell set gypsum core includes an interlocking matrix of gypsum having air voids distributed therein. The air voids define cells having cell walls formed by the interlocking matrix. The interlocking matrix further includes channels distributed therein. The channels interconnect the air voids and comprise openings in the cell walls.

An open cell set gypsum core includes an interlocking matrix of gypsum having air voids distributed therein. The air voids define cells having cell walls formed by the interlocking matrix. The interlocking matrix further includes channels distributed therein. The channels interconnect the air voids and comprise openings in the cell walls.

The present invention is directed to a gypsum board and a method of making such gypsum board. For instance, the gypsum board comprises a gypsum core, a first facing material, and a second facing material wherein the first facing material and the second facing material sandwich the gypsum core. The gypsum core comprises a first gypsum core section and a second gypsum core section each comprising gypsum, wherein the first gypsum core section comprises a polyol compound and has a density higher than a density of the second gypsum core section.

The present invention is directed to a gypsum board and a method of making such gypsum board. For instance, the gypsum board comprises a gypsum core, a first facing material, and a second facing material wherein the first facing material and the second facing material sandwich the gypsum core. The gypsum core comprises a first gypsum core section and a second gypsum core section each comprising gypsum, wherein the first gypsum core section comprises a polyol compound and has a density higher than a density of the second gypsum core section.

The present invention is directed to an improved gypsum board and a method of making such gypsum board. For instance, the method comprises: providing a first facing material, depositing a gypsum slurry comprising at least stucco and water on the first facing material, providing a second facing material on the gypsum slurry, and allowing the stucco to convert to calcium sulfate dihydrate, wherein the method further comprises a step of providing a dry starch layer including a dry starch at an interface between the first facing material and the gypsum slurry, the second facing material and the gypsum slurry, or both.

The present invention is directed to an improved gypsum board and a method of making such gypsum board. For instance, the method comprises: providing a first facing material, depositing a gypsum slurry comprising at least stucco and water on the first facing material, providing a second facing material on the gypsum slurry, and allowing the stucco to convert to calcium sulfate dihydrate, wherein the method further comprises a step of providing a dry starch layer including a dry starch at an interface between the first facing material and the gypsum slurry, the second facing material and the gypsum slurry, or both.

A method for making a gypsum board including: combining a first plurality of particles including at least about 50 wt. % calcium sulfate dihydrate and about 0.05 wt. % to about 10 wt. % hydrophobic material and having a D50 particle size of about 200 μm to about 800 μm with a second plurality of particles including calcium sulfate hemihydrate to form a combined mixture of calcium sulfate; adding water to the combined mixture of calcium sulfate to make an aqueous gypsum slurry; depositing a core layer including the aqueous gypsum slurry over a forming surface; and allowing the core layer to set, thereby forming a set gypsum core.