United States Gypsum Company

Qingxia Liu

Michael Patrick Shake

David R Blackburn

Qiang Yu

John W Wilson

Dennis Mark Lettkeman

Xuming Wang

Paul W Reed

Brian Randall

David Paul Miller

David McDonald

Sharon Louise Tracy

Alfred C Li

James Wittbold

Chris C Lee

Rafael Bury

Michael Lawrence Bolind

Runhai Lu

Bruce Lynn Petersen

Kumar C Natesaiyer

John Ellicson

Dick C Engbrecht

Donald L Roelfs

John L Fall

Frederick Thomas Jones

Wenqi Luan

Jeffrey F Grussing

Michael R Lynn

W David Song

Michael L Cloud

Kevin W Moyer, Jr

Stewart E Hinshaw

Richard Spencer

James R Wittbold

Kevin W Moyer

David Mcdonald

Sharon L Tracy

Chris Lee

R Lynn Michael

Michael Lee Cloud

David Song Weixin

Paul Reed

Xuming Dept Of Metallurgical Engineering Wang

A fibrous mat-faced cementitious article comprising (a) a cementitious core, and (b) a first fibrous mat comprising polymer or mineral fibers and a hydrophobic finish on at least one surface thereof, wherein the hydrophobic finish is in contact with the cementitious core, and a method of preparing a fibrous mat-faced cementitious article, as well as a method of preparing a water-resistant cementitious article comprising (a) preparing an aqueous siloxane dispersion, wherein the dispersion comprises about 4 wt. % to about 8 wt. % siloxane, (b) combining the siloxane dispersion with a cementitious mixture to provide a cementitious slurry, (c) depositing the cementitious slurry onto a substrate, and (d) allowing the cementitious slurry to harden, thereby providing a cementitious article.

Water resistant cementitious article and method for preparing same

A cementitious article and a method of making a cementitious article are disclosed. The cementitious article comprises a cementitious component that comprises a polyvinyl acetate type polymer, a monobasic phosphate, and optionally boric acid. Cementitious articles, such as board, are prepared such that the polyvinyl acetate type polymer, the monobasic phosphate, and optionally boric acid can be present in the cementitious core, and/or in dense layers if present. The concentration of the polyvinyl acetate type polymer, monobasic phosphate, and optionally boric acid in the cementitious article can increase from a central region A to peripheral regions B and C, respectively. In some embodiments, the polyvinyl acetate type polymer is a polyvinyl alcohol and the monobasic phosphate is monoammonium phosphate.

Cementitious article and method for preparing the same

A gypsum slurry is described that includes water, a hydraulic component comprising at least 50% calcined gypsum by weight based on the dry weight of the hydraulic component, foam, a defoamer and a polycarboxylate dispersant. In some embodiments of the invention, the defoamer is combined with the dispersant prior to being added to the gypsum slurry. The defoamer and dispersant can be added as a physical mixture, wherein the defoamer is attached onto the dispersant polymer, or a combination thereof. A gypsum building panel is made from the gypsum slurry.

Foamed slurry and building panel made therefrom

Polymerization of siloxane is improved using a gypsum-based slurry that includes stucco, Class C fly ash, magnesium oxide and an emulsion of siloxane and water. This slurry is used in a method of making water-resistant gypsum articles that includes making an emulsion of siloxane and water, then combining the slurry with a dry mixture of stucco, magnesium oxide and Class C fly ash. The slurry is then shaped as desired and the stucco is allowed to set and the siloxane polymerizes. The resulting product is useful for making a water-resistant gypsum panel having a core that includes interwoven matrices of calcium sulfate dihydrate crystals and a silicone resin, where the interwoven matrices have dispersed throughout them a catalyst comprising magnesium oxide and components from a Class C fly ash.

Siloxane polymerization in wallboard

A gypsum slurry is described that includes water, a hydraulic component comprising at least 50% calcined gypsum by weight based on the dry weight of the hydraulic component, foam, a defoamer and a polycarboxylate dispersant. In some embodiments of the invention, the defoamer is combined with the dispersant prior to being added to the gypsum slurry. The defoamer and dispersant can be added as a physical mixture, wherein the defoamer is attached onto the dispersant polymer, or a combination thereof. In some embodiments, a gypsum building panel is made from the gypsum slurry.

An improved gypsum slurry that includes water, calcium sulfate hemihydrate, a polycarboxylate dispersant and a modifier. The modifier is chemically configured to improve the efficacy of the polycarboxylate dispersant. Preferred modifiers include cement, lime, slaked lime, soda ash, carbonates, silicates and phosphates.

Modifiers for gypsum slurries and method of using them

The process of the present invention includes obtaining a feed material having an initial median particle size. A solution of a polycarboxylate dispersant in water is formed, then the feed material is added to the solution to form a slurry. The slurry is wet-ground to reduce the median particle size of the feed material. Optionally, the total amount of polycarboxylate dispersant is divided into a plurality of doses that are added periodically over the total grinding time.

Wet-grinding gypsum with polycarboxylates

A method for calcining gypsum in a pressurized reactor by injecting combustion gases and air into the pressurized reactor to create a fluidized bed of gypsum, and heating the fluidized bed of gypsum in the pressurized reactor sufficiently to form a calcined hemihydrate.

Method and apparatus for pressurized calcination of gypsum

A method for forming a gypsum slurry comprises the steps of combining gypsum and water to form a slurry, combining cellulose ether with at least a second material configured to delay solubilization of the cellulose ether, and adding the combined cellulose ether and at least a second material to the slurry.

Methods and systems for preparing gypsum slurry containing a cellulose ether

A method of continuously forming a multilayer panel includes making a gypsum slurry, then dividing the gypsum slurry into at least a primary gypsum slurry and a secondary gypsum slurry. An additive slurry having water and an intumescent material is created, then added to the secondary gypsum slurry to make an expandable layer slurry that is spread over at least a portion of a facing material. The primary gypsum slurry is distributed over the secondary gypsum slurry over the facing material and the expanding layer slurry to form a core. Optionally, another layer, an edge coating, is applied to the expanding layer for additional fire protection. The edge coating includes a second intumescent material. During a fire, the expanding layer expands to increase the thickness of the fire exposed gypsum panel and the edge coating expands to seal the gap between adjoining gypsum panels.

Fire-resistant gypsum panel

A gypsum slurry includes water, a hydraulic component including stucco and a polycarboxylate dispersant. The dispersant has two repeating units wherein the first repeating unit is an olefinic unsaturated mono-carboxylic acid repeating unit or an ester or salt, and the second repeating unit is a vinyl or allyl group bound to a polyether by an ether linkage. The slurry can be made into a gypsum panel.

Gypsum products utilizing a two-repeating unit dispersant and a method for making them

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Vernon Hills, IL, United States of America

Qingxia Liu