The invention concerns a method for producing gypsum boards, wherein a liquefier for the gypsum slurry is foamed with gas to provide a foam having a water content of less than 85 wt.-%, then incorporated into a gypsum/water mixture and the mixture thus obtained is applied on a two dimensional substrate. The incorporation of the liquefier in foamed form allows for a significant reduction of the amount of liquefier required to provide a desired flowability of the gypsum/water mixture, thus allowing the production of gypsum boards with similar characteristics with less liquefier. The invention further concerns gypsum board prepared using this process, apparatuses for producing gypsum boards using this process and the use of a corresponding liquefier foam to minimize the amount of liquefier required to establish a desired flowability of a gypsum/water mixture.

A process for preparing powdered dispersants comprising at least 90% by weight of at least one copolymer CP of the polycarboxylate ether type. The powdered dispersants can be easily dispersed in water. The invention also relates to the use of such powdered dispersants in mineral binder compositions, in particular dry mortars, concrete or gypsum formulations.

Disclosed is a composite gypsum board comprising a set gypsum core disposed between face (e.g., Manila) and back (e.g., Newsline) cover sheets. The set gypsum core is formed from a core slurry comprising stucco, water, and optional additives, such as foaming agent, migrating starch, accelerator, retarder, dispersant, etc. A dense layer formed from a dense layer slurry comprising stucco, water, fiber (e.g., paper fiber), and optionally, strength-enhancing starch, is disposed between the core and the face paper. The dense layer slurry contains a greater concentration of fiber, and optionally, strength-enhancing starch, than the core slurry, but the concentration of one or more other additives (e.g., accelerator, retarder, dispersant, or combinations thereof) is lower or the same in the dense slurry as compared with the core slurry. Also disclosed is a method of making board using one board mixer. In embodiments, paper fiber is added to water to form a suspension. The suspension is introduced, while in a non-laminar state, into the dense slurry. Further disclosed is apparatus, such as an extractor and an additive injection system, which can be a part of a cementitious slurry mixing and dispensing assembly.

Disclosed is a composite gypsum board comprising a set gypsum core disposed between face (e.g., Manila) and back (e.g., Newsline) cover sheets. The set gypsum core is formed from a core slurry comprising stucco, water, and optional additives, such as foaming agent, migrating starch, accelerator, retarder, dispersant, etc. A dense layer formed from a dense layer slurry comprising stucco, water, fiber (e.g., paper fiber), and optionally, strength-enhancing starch, is disposed between the core and the face paper. The dense layer slurry contains a greater concentration of fiber, and optionally, strength-enhancing starch, than the core slurry, but the concentration of one or more other additives (e.g., accelerator, retarder, dispersant, or combinations thereof) is lower or the same in the dense slurry as compared with the core slurry. Also disclosed is a method of making board using one board mixer. In embodiments, paper fiber is added to water to form a suspension. The suspension is introduced, while in a non-laminar state, into the dense slurry. Further disclosed is apparatus, such as an extractor and an additive injection system, which can be a part of a cementitious slurry mixing and dispensing assembly.

Disclosed is a composite gypsum board comprising a set gypsum core disposed between face (e.g., Manila) and back (e.g., Newsline) cover sheets. The set gypsum core is formed from a core slurry comprising stucco, water, and optional additives, such as foaming agent, migrating starch, accelerator, retarder, dispersant, etc. A dense layer formed from a dense layer slurry comprising stucco, water, fiber (e.g., paper fiber), and optionally, strength-enhancing starch, is disposed between the core and the face paper. The dense layer slurry contains a greater concentration of fiber, and optionally, strength-enhancing starch, than the core slurry, but the concentration of one or more other additives (e.g., accelerator, retarder, dispersant, or combinations thereof) is lower or the same in the dense slurry as compared with the core slurry. Also disclosed is a method of making board using one board mixer. In embodiments, paper fiber is added to water to form a suspension. The suspension is introduced, while in a non-laminar state, into the dense slurry. Further disclosed is apparatus, such as an extractor and an additive injection system, which can be a part of a cementitious slurry mixing and dispensing assembly.

Antimicrobial and odor control masonry-based material compositions used to form a structure or surface include a base material and a halo active aromatic sulfonamide compound of Formula (I):

##STR00001##

wherein the variables R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, M and n are disclosed herein. The compositions and processes utilizing the same can be used to form surfaces and structures that maintain antimicrobial and odor-controlling properties over extended time periods.

Antimicrobial and odor control masonry-based material compositions used to form a structure or surface include a base material and a halo active aromatic sulfonamide compound of Formula (I):

##STR00001##

wherein the variables R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, M and n are disclosed herein. The compositions and processes utilizing the same can be used to form surfaces and structures that maintain antimicrobial and odor-controlling properties over extended time periods.

Antimicrobial and odor control masonry-based material compositions used to form a structure or surface include a base material and a halo active aromatic sulfonamide compound of Formula (I):

##STR00001##

wherein the variables R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, M and n are disclosed herein. The compositions and processes utilizing the same can be used to form surfaces and structures that maintain antimicrobial and odor-controlling properties over extended time periods.

A joint compound system includes a set-inhibited, pre-wetted, setting-type, ready-mix joint compound and a set initiator. The set-inhibited, pre-wetted, setting-type joint compound includes a ready-mixed, setting-type joint compound base with a calcium-free phosphate set preventing agent that impedes chemical hydration of a gypsum component of the setting-type joint compound. The joint compound base is free of calcium carbonate. The set initiator includes alum to reinitiate the chemical hydration reactions.

A building construction product with an electroconductive surface, the building construction product comprising a core with one or more surfaces covered by an electroconductive paper comprising carbon fibers, the electroconductive paper being attached to the one or more surfaces of the core. Methods and materials for producing the building construction products with an electroconductive surface and products and methods for shielding an area from electromagnetic waves.