United States Gypsum Company

Knauf Gips Kg

Yijun Sang

Weixin David Song

Brian J Christ

Mark K Hemphill

Alfred C Li

Chris C Lee

Cesar Chan

Annamaria Vilinska

Fredrick T Jones

Bradley W Todd

Gregg G Diefenbacher

Suman Sinha Ray

Runhai Lu

Guy Rosenthal

Te Hua Lau

James W Barber

Renee J Weinberger

Mark Antosh

David Song

Yongman Kim

Nicholas S Jones

Kevern O Fraser

Jon Cross

Guy L Rosenthal

Weixin D Song

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.

Board with fiber-reinforced dense layer

Disclosed are product (e.g., board), slurry, and methods relating to an uncooked starch that can be used to enhance strength in one or more gypsum layers in the board. The uncooked starch has a hot water viscosity of from about 20 BU to about 300 BU according to the HWVA method, and/or a mid-range peak viscosity of from about 120 Brabender Units to about 1000 Brabender Units.

Gypsum composition comprising uncooked starch having mid-range viscosity, and methods and products related thereto

An open cell set gypsum core includes an interlocking matrix of gypsum having air voids distributed therein. The air voids define cells having cell walls formed by the interlocking matrix. The interlocking matrix further includes channels distributed therein. The channels interconnect the air voids and comprise openings in the cell walls.

Open-celled gypsum core, gypsum acoustic panel, and method for making same

Disclosed is a composite gypsum board comprising a board core and a concentrated layer of substantial thickness (e.g., at least about 0.02 inches). The concentrated layer includes a higher weight percentage of an enhancing additive than the hoard core. The board core has a thickness greater than the thickness of the concentrated layer and forms the bulk of the board volume. The concentrated layer has a higher density (e.g., at least about 1.1 times greater) than the density of the board core. Also disclosed is a method of preparing a composite gypsum board.

Composite gypsum board and methods related thereto

An accelerator for accelerating the rate of hydration of calcined gypsum is disclosed. The accelerator comprises calcium sulfate dihydrate particles and a starch. The starch has a cold water solubility of at least about 25% (e.g., at least about 35%) and a viscosity of about 25 Brabender Units (BU) or less when the starch is in a 30% aqueous slurry at 92&#xb0; C. Also disclosed are a method of preparing an accelerator, method of hydrating stucco to form set gypsum, slurry, and method of making gypsum board.

Accelerator comprising starch, and related board, slurries, and methods

Disclosed is an acid-modified flour and a method of making the acid-modified flour. The acid-modified flour is desirably prepared using a dry milling process. A starting flour is combined with a strong acid to form a mixture. The mixture is heated. A neutralizer is added to increase the pH of the mixture. If desired, the mixture can be dried and any agglomerates can be removed. The acid-modified flour can be used as a binder in a slurry for preparing one or more gypsum layers in a gypsum board.

Flour binder for gypsum board, and related methods, product, and slurries

Disclosed are product (e.g., panels), slurry, and methods relating to a pregelatinized starch having a mid-range viscosity (i.e., from about 20 centipoise to about 700 centipoise), and an extruded pregelatinized starch.

Pregelatinized starch with mid-range viscosity, and product, slurry and methods related thereto

Disclosed are product (e.g., panels), slurry, and methods relating to a pregelatinized starch having a mid-range viscosity (i.e., from about 20 centipoise to about 700 centipoise).

Disclosed is a composite gypsum board comprising a board core comprising set gypsum sandwiched between face and back cover sheets. The composite gypsum board also comprises an intermediate sheet between the board core and the face cover sheet, with a thin, dense gypsum layer disposed between the intermediate sheet and the face cover sheet. Optionally, a second dense gypsum layer can be disposed between a first major side of the board core and the back cover sheet. Also disclosed is a method of preparing a composite gypsum board in which an intermediate sheet is applied over a dense gypsum layer disposed on a face cover sheet. A back cover sheet is applied to the other major side of the board core, with a second dense gypsum layer optionally disposed therebetween.

Composite gypsum board and related methods

Disclosed is a composite gypsum board comprising a board core and a concentrated layer of substantial thickness (e.g., at least about 0.02 inches). The concentrated layer includes a higher weight percentage of an enhancing additive than the board core. The board core has a thickness greater than the thickness of the concentrated layer and forms the bulk of the board volume. The concentrated layer has a higher density (e.g., at least about 1.1 times greater) than the density of the board core. Also disclosed is a method of preparing a composite gypsum board.

A layered gypsum wallboard can include: a gypsum board having opposing front and back faces, wherein the gypsum board comprises a first cover sheet material at the front face, a second cover sheet material at the back face, and a gypsum core layer comprising gypsum; an adhesive layer on the second cover sheet material of the gypsum board, the adhesive including a polymer having a glass transition temperature (T) of &#x2212;10&#xb0; C. to 30&#xb0; C.; an intermediate gypsum layer including gypsum on the adhesive layer such that the adhesive layer is between the second cover sheet material and the intermediate gypsum layer, wherein the adhesive layer and the intermediate gypsum layer have a combined thickness of 0.09 inches to 0.25 inches; and a third cover sheet material, wherein the intermediate gypsum layer is between and in contact with the adhesive layer and the third cover sheet material.

Methods for making high sound transmission class gypsum boards and gypsum boards made by the method

Disclosed are product (e.g., panels), slurry, and methods relating to an uncooked starch having a mid-range peak viscosity (i.e., from about 120 Brabender Units to about 900 Brabender Units).

Disclosed are methods relating to an extruded pregelatinized, partially hydrolyzed starch prepared by mixing at least water, non-pregelatinized starch, and acid to form a starch precursor. The acid can be a weak acid that substantially avoids chelating calcium ions or a strong acid in a small amount. In the method, pregelatinization and acid-modification of the starch precursor occurs in one step in an extruder. Also disclosed are methods of preparing board using the starch prepared according to the methods, as well as starches and boards prepared by various methods of the invention.

Growing community of inventors

Oak Park, IL, United States of America

Yijun Sang