Abstract: A slurry for manufacturing gypsum board is disclosed. The slurry comprises calcined gypsum, water, a foaming agent, and a thickening agent. The thickening agent of the present disclosure acts to improve the cohesiveness of the slurry without adversely affecting the setting time of the slurry, the paper-to-core bond (wet and dry), or the head of the slurry by acting as a defoaming agent or coalescing agent. Examples of suitable thickening agents include cellulose ether and co-polymers containing varying degrees of polyacrylamide and acrylic acid. 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.

Abstract: Compositions for gypsum board are disclosed, comprising a mixture of a gypsum slurry and a pre-generated foam and a coalescing agent. The coalescing agent comprises one or more coalescing agents that are added to the composition singly, separately or in combination to change the size and distribution of the air bubbles in the foamed gypsum slurry. The resulting gypsum cores have increased nail pull resistance and an improved facer/gypsum core bond.

Abstract: Compositions for gypsum board are disclosed, comprising a mixture of a gypsum slurry and a pre-generated foam and a coalescing agent. The coalescing agent comprises one or more coalescing agents that are added to the composition singly, separately or in combination to change the size and distribution of the air bubbles in the foamed gypsum slurry. The resulting gypsum cores have increased nail pull resistance and an improved facer/gypsum core bond.

Abstract: The disclosure relates to a method for effectively and efficiently adding sodium trimetaphosphate to a gypsum slurry. In one exemplary embodiment, the sodium trimetaphosphate is added at the same time as foam is added to the gypsum slurry through the foam waterline. In another exemplary embodiment, the sodium trimetaphosphate is added at the same time as additional water is added to the gypsum slurry through the gauging waterline. The sodium trimetaphosphate can be added to either or both waterlines in its dry form or in a diluted solution.

Abstract: A gypsum composition for use as a wallboard core contains stucco, water, a styrene acrylic or acrylic hybrid copolymer, and a reduced amount of starch. A finished wallboard using this composition has similar properties, including compressive strength and paper core bond strength of a finished board, to wallboards made from compositions having higher quantities of starch. A method for producing such a composition is shown, the method requiring mixing of stucco and pulp water in a pin mixer, with the addition of starch and the styrene acrylic or acrylic hybrid copolymer.

Abstract: The disclosure relates to a method for effectively and efficiently adding sodium trimetaphosphate to a gypsum slurry. In one exemplary embodiment, the sodium trimetaphosphate is added at the same time as foam is added to the gypsum slurry through the foam waterline. In another exemplary embodiment, the sodium trimetaphosphate is added at the same time as additional water is added to the gypsum slurry through the gauging waterline. The sodium trimetaphosphate can be added to either or both waterlines in its dry form or in a diluted solution.

Abstract: Gypsum wallboard compositions are disclosed which contain functionalized styrene butadiene latex polymers. Methods for the use of the compositions in the manufacture of wallboard panels and sheets is presented.

Abstract: Gypsum wallboard compositions are disclosed which contain functionalized styrene butadiene latex polymers. Methods for the use of the compositions in the manufacture of wallboard panels and sheets is presented.

Abstract: Compositions useful for the preparation of lightweight, high strength wallboards, and methods of making same are disclosed. The composition includes a slurry of calcium sulfate hemihydrate (stucco), water, starch, and a foam. The foam acts to provide large bubbles within the core slurry, thereby lightening the weight of the wallboard. The composition and method provide wallboards having lighter weights compared to standard wallboard, increased core strength, and increased paper-to-core bonding.

Abstract: The invention provides a method of providing void spaces in gypsum wallboard and in a gypsum core composition such that the weight of the gypsum product is reduced without deleteriously affecting its mechanical properties. More specifically, the invention provides a method of providing void spaces in a gypsum wallboard comprising the step of adding air bubbles having different relative stabilities to a gypsum slurry, wherein the less stable air bubbles are sufficiently unstable such that they coalesce on contact with each other in the slurry to form larger air bubbles, and the weight ratio of the less stable air bubbles to the more stable air bubbles initially added to the slurry is such that there are a sufficient number of more stable air bubbles to prevent a majority of the less stable air bubbles from becoming large enough to rupture before the slurry sets sufficiently to prevent the slurry from filling void spaces left by ruptured bubbles.

Abstract: Compositions useful for the preparation of lightweight, high strength wallboards, and methods of making same are disclosed. The composition includes a slurry of calcium sulfate hemihydrate (stucco), water, starch, and a foam. The foam acts to provide large bubbles within the core slurry, thereby lightening the weight of the wallboard. The composition and method provide wallboards having lighter weights compared to standard wallboard, increased core strength, and increased paper-to-core bonding.

Abstract: A method of producing calcium sulfate &agr;-hemihydrate is disclosed, including the steps of exposing a mixture including a calcium sulfate form selected from the group consisting of calcium sulfate dihydrate, calcium sulfate &bgr;-hemihydrate, water-soluble calcium sulfate anhydrite, and mixtures thereof, water, and a crystallization catalyst, to microwave radiation to produce calcium sulfate &agr;-hemihydrate; and separating at least a portion of the calcium sulfate &agr;-hemihydrate to provide a solid comprising calcium sulfate &agr;-hemihydrate and a filtrate and/or remainder that can be recycled to provide at least one of a calcium sulfate form, water, a crystallization catalyst, a crystal habit modifier, and a surfactant for use in production of additional &agr;-hemihydrate.

Abstract: A joint compound includes water, calcium carbonate, and a water-soluble polymeric set retarder formed from a monomer having two or more carboxyl groups. The joint compound is useful in various applications and in a hybrid joint compound made with a calcium sulfate hemihydrate setting-type joint compound.

Abstract: Gypsum wallboard compositions are disclosed which contain functionalized styrene butadiene latex polymers. Methods for the use of the compositions in the manufacture of wallboard panels and sheets is presented.

Abstract: A joint compound includes water, calcium carbonate, and a water-soluble polymeric set retarder formed from a monomer having two or more carboxyl groups. The joint compound is useful in various applications and in a hybrid joint compound made with a calcium sulfate hemihydrate setting-type joint compound.

Abstract: Gypsum wallboard compositions are disclosed which contain functionalized styrene butadiene latex polymers. Methods for the use of the compositions in the manufacture of wallboard panels and sheets is presented.

Abstract: Gypsum wallboard compositions are disclosed which contain functionalized styrene butadiene latex polymers. Methods for the use of the compositions in the manufacture of wallboard panels and sheets is presented.

Abstract: The invention provides a method of providing void spaces in gypsum wallboard and in a gypsum core composition such that the weight of the gypsum product is reduced without deleteriously affecting its mechanical properties. More specifically, the invention provides a method of providing void spaces in a gypsum wallboard comprising the step of adding air bubbles having different relative stabilities to a gypsum slurry, wherein the less stable air bubbles are sufficiently unstable such that they coalesce on contact with each other in the slurry to form larger air bubbles, and the weight ratio of the less stable air bubbles to the more stable air bubbles initially added to the slurry is such that there are a sufficient number of more stable air bubbles to prevent a majority of the less stable air bubbles from becoming large enough to rupture before the slurry sets sufficiently to prevent the slurry from filling void spaces left by ruptured bubbles.

Abstract: A method of producing calcium sulfate &agr;-hemihydrate, including the steps of exposing a mixture including a calcium sulfate form selected from the group consisting of calcium sulfate dihydrate, calcium sulfate &bgr;-hemihydrate, water-soluble calcium sulfate anhydrite, and mixtures thereof, water, and a crystallization catalyst, to microwave radiation to produce calcium sulfate &agr;-hemihydrate; and separating at least a portion of the calcium sulfate &agr;-hemihydrate to provide a solid comprising calcium sulfate &agr;-hemihydrate and a remainder, is disclosed.

Abstract: A joint compound includes water, calcium carbonate, and a water-soluble polymeric set retarder formed from a monomer having two or more carboxyl groups. The joint compound is useful in various applications and in a hybrid joint compound made with a calcium sulfate hemihydrate setting-type joint compound.