A wallboard comprising a gypsum core and a facing layer, containing a fungicidally effective amount of thiabendazole (TBZ) and 2-butyl-1,2-benzisothiazolin-3-one (BBIT).

A method of preparing an admixture for a plasterboard is disclosed. An admixture prepared by the method and a composition for forming a plasterboard containing the admixture are also disclosed. The method includes sulfonation of polystyrene using sulfuric acid to give an admixture including a sulfonated polystyrene (SPS)-based compound of formula 1 below. The admixture enables regulation of properties of a plasterboard, such as foam size, flowability, and setting time, by regulating a degree of sulfonation (DS) of the SPS-based compound:

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The invention concerns an anti-sagging additive for producing shaped gypsum articles. The additive is boron-free and comprises L-tartaric acid and/or L-tartrates and a pH-enhancing compound.

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.

Water-resistant gypsum products may be produced using a novel catalyst that includes calcium aluminate cement and/or calcium sulfoaluminate cement. For example, a water-resistant gypsum panel may have a core comprising: interwoven matrices of calcium sulfate dihydrate crystals and a silicone resin, wherein the interwoven matrices have dispersed throughout them a siloxane polymerization catalyst comprising (a) 55 wt % to 100 wt % calcium aluminate cement and/or calcium aluminate cement and (b) 0 wt % to 45 wt % and magnesium oxide, wherein the weight ratio of the siloxane polymerization catalyst to the calcium sulfate dihydrate is 0.01-5:100. The water-resistant gypsum panel may have an absence of one or more of: Portland cement, limestone, aragonite, calcite, dolomite, and slaked lime.

The present invention relates to a gypsum composition comprising recycled gypsum and a foam former comprising at least one alpha-sulfo fatty acid disalt, to a process for production thereof and to an article comprising the gypsum composition of the invention. The present invention further relates to the use of a foam former comprising at least one alpha-sulfo fatty acid disalt for reducing the wet density of an aqueous gypsum composition having a recycled gypsum content of at least 0.5% by weight.

Techniques of forming a foamed insulation material from gypsum waste are disclosed herein. One example technique includes mechanically comminuting the gypsum waste from an original size into particles of gypsum at a target size smaller than the original size and mixing the particles of the gypsum with a binder to form a mixture of particles and binder. The binder is configured to bind the particles of gypsum upon hydration. The example technique can further include performing air entrainment on the mixture until a foam is formed from the mixture having the particles of gypsum and binder. The foam has water that causes the binder to bind the particles of gypsum. The example technique can then include removing moisture from the mixture with the formed foam to form a foamed insulation material from the particles of gypsum.

This invention provides gypsum wallboards with a unique microstructure where the walls between voids are enhanced in thickness and strength to substantially improve the strength and handling properties of the wallboards. A method of making lightweight gypsum wallboards is also provided.

The present disclosure is directed to a method of manufacturing gypsum board as well as the resulting gypsum board. The method comprises providing a gypsum slurry with a shrinkage-reducing additive comprising a metal salt of an acid, a silica, or a mixture thereof. As a result, the gypsum board includes gypsum and a shrinkage-reducing additive comprising a metal salt of an acid, a silica, or a mixture thereof. The gypsum board exhibits an area shrinkage of less than 10%.

Aqueous water repellency dispersions for use in the manufacture of gypsum wallboard, comprising a wax phase including a wax and a functionalized wax, an aqueous phase including a Kraft lignin and a water soluble base in an amount sufficient to solubilize the Kraft lignin.