United States Gypsum Company

Other

Srinivas Veeramasuneni

Qiang Yu

Weixin David Song

Alfred C Li

Wenqi Luan

Salvatore C Immordino, Jr

Christopher R Nelson

William A Frank

Frederick Thomas Jones

Alfred Li

Michael Patrick Shake

Mark H Englert

Robert H Negri

Steven W Sucech

Cesar Chan

Christopher Robert Nelson

Guy Rosenthal

David Paul Miller

Raymond John Mlinac

Jeffrey F Grussing

Yanfei Peng

Bangji Cao

Marianela Perez-Pena

David D Pelot

Samar Emami

Rodney Phillip Musselman

John Jason Roxburgh

Kathryn Capacasa

Juan Carlos Ruiz Castañeda

Juan Carlos Ruiz CASTAÑEDA

A reduced weight, reduced density gypsum panel that includes high expansion vermiculite with fire resistance capabilities that are at least comparable to (if not better than) commercial fire rated gypsum panels with a much greater gypsum content, weight and density.

Lightweight, reduced density fire rated gypsum panels

A gypsum-based composition of calcium sulfate hemihydrate with (a) alum and calcium carbonate and/or (b) zeolite and sodium percarbonate for making foamed gypsum slurry. A method to make foamed gypsum slurry from the composition. A method to make foamed gypsum product from the composition. A cavity wall having a cavity filled with the foamed gypsum product.

Method for making a lightweight gypsum composition with internally generated foam and products made from same

Disclosed herein are gypsum products with at least one high efficiency heat sink additive. The gypsum products, e.g., gypsum panels, are less susceptible to the damaging effects of extreme heat as the temperature rises due to the presence of the at least one additive.

Gypsum products with high efficiency heat sink additives

A method of preparing a reduced weight, reduced density gypsum panel that includes high expansion vermiculite with fire resistance that meet or exceed one or more industry standard fire tests.

Method of making lightweight, reduced density fire rated gypsum panels

In a first embodiment of the invention, aged brushite is combined with calcium sulfate hemihydrate and water to make a gypsum slurry. Aged brushite slurry behaves similarly to calcium sulfate dihydrate to act as a seed crystal and rapidly initiate crystallization. The brushite slurry does not require the addition of a coating to maintain its activity over time compared to calcium sulfate dihydrate set accelerators. A gypsum-based product made using brushite slurry as the set accelerator is a second embodiment. The product has the brushite molecules integrated as part of the calcium sulfate dihydrate matrix and is distributed throughout the matrix.

Set accelerator for gypsum hydration

A moisture resistant gypsum-based product, e.g., a gypsum board, is made by adding a small amount of a siloxane to the aqueous slurry used to make the gypsum-based product along with a small amount of a dead burned magnesium oxide catalyst to enhance the curing of the siloxane. In the preferred embodiment, the siloxane is formed into an aqueous emulsion in situ with no chemical emulsifier.

Method of making water-resistant gypsum-based article

A method of making a rapid setting composition for cement boards is disclosed. Compositions including portland cement, fly ash, gypsum, alkanolamine and phosphate are disclosed. A synergistic interaction between the alkanolamine and phosphate increases the effectiveness of accelerating reactions thus allowing for quick setting and increased early-age compressive strength compositions.

Very fast setting cementitious composition with high early-age compressive strength

Articles, including fiberboard, are made from a pumpable, flowable slurry including alpha-calcined calcium sulfate hemihydrate anchored in pores of host particles, alpha-calcined calcium sulfate hemihydrate, a silicone compound, magnesium oxide, and water. The magnesium oxide catalyzes the reaction of the silicone compound into a silicone resin. In a preferred method of making a water resistant fiberboard calcium sulfate dihydrate is combined with the host particles and water to form a slurry which is heated under pressure to calcine the calcium sulfate dihydrate to form alpha-calcined calcium sulfate hemihydrate. After relieving the pressure, a silicone compound and magnesium oxide are added to the slurry. The slurry is dewatered to form a filter cake, which is then formed into a desired shape and allowed to set.

Fiberboard with improved water resistance

The invention provides a board forming system comprising a forming table comprising a belt with a surface for conveying a backing layer; a mixer fitted with a mechanism capable of depositing cementitious slurry material over a top surface of the backing layer; and a slurry spreader positioned downstream of the mixer, wherein a portion of the slurry spreader comprises a plurality of apertures which are connected to a source of pressurized fluid. The slurry spreader is configured such that the pressurized fluid flows out of the slurry spreader through the apertures so as to provide a continuous film of fluid across an outer surface of the slurry spreader. The slurry spreader is positioned such that it can contact at least a portion of the cementitious slurry after the slurry exits the discharge and before the slurry is spread across the width of the backing layer such that the thickness of the slurry is approximately equal to the desired slurry thickness for board formation. The invention further provides methods for forming cementitious board comprising the use of the slurry spreader.

Slurry spreader for cementitious board production

A mold-resistant gypsum panel includes a core of an interlocking matrix of calcium sulfate dihydrate crystals, a facing material on at least one side of the panel and a salt of pyrithione dispersed through both the core and the facing materials. A method of making a mold-resistant gypsum product is also provided. A slurry of calcined gypsum, water and a water-soluble pyrithione salt is formed, then deposited on a sheet of facing material. The slurry on the facing material is shaped into a panel and maintained under conditions sufficient for the calcined gypsum to react with the water to form a core comprising an interlocking matrix of set gypsum crystals. Heating of the panel causes evaporation of the water that did not react with the calcined gypsum.

Mold-resistant gypsum panel and method of making same

A composition including, but not limited to, a mixture of a calcium sulfate material, water, and a tetrametaphosphate compound is disclosed. Desirably, the inclusion of the tetrametaphosphate compound (e.g., salt or ion) in a pre-set treatment of a calcium sulfate material enhances the resistance to permanent deformation (e.g., sag), dimensional stability, and/or compressive strength of the composition while also preferably avoiding any significant retardive effect on the rate of hydration of calcined gypsum to calcium sulfate dihydrate. A set gypsum-containing product and a method for producing a set gypsum-containing product having increased resistance to permanent deformation are also disclosed.

Growing community of inventors

Round Lake, IL, United States of America

Srinivas Veeramasuneni