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.

The present invention is directed to a gypsum board and a method of making such gypsum board. For instance, the gypsum board comprises a gypsum core, a first facing material, and a second facing material wherein the first facing material and the second facing material sandwich the gypsum core. The gypsum core comprises a first gypsum core section and a second gypsum core section each comprising gypsum, wherein the first gypsum core section comprises a polyol compound and has a density higher than a density of the second gypsum core section.

Disclosed are a composite gypsum board and a method of preparing composite gypsum board. The board contains a set gypsum core sandwiched between two cover sheets. The core is formed from a slurry containing stucco, water, and optional ingredients such as foaming agent, accelerator, retarder, polyphosphate, starch, and dispersant, and core intumescent material. The board also contains at least one skim coat and/or hard edges. A face skim coat layer can be included on one side of the core, facing a face cover sheet. A back skim coat layer can be included on the other side of the core, facing a back cover sheet. Hard edges are known in the art and can be formed, e.g., continuously from a stucco slurry for forming the face and/or back skim coats. Preferably, the back skim coat layer and/or the hard edges are formed from a slurry containing stucco, water, skim coat or edge intumescent material (which have the same desired characteristics), and other optional additives as desired. The skim coat or edge intumescent material can be composed of the same material as the core intumescent material, if desired, but the skim coat and/or edge intumescent material is present in a higher relative concentration in its respective slurry than the amount of core intumescent material in the core slurry. Examples of suitable intumescent materials include expandable vermiculite (e.g., No. 4 or No. 5 according to the US naming system, or combinations thereof), expandable graphite, perlite, or any combination thereof.

In the present disclosure, a method of forming a gypsum panel is disclosed. The method comprises: providing a first facing material, forming a starch slurry by combining starch and water at a shear rate of 3,000 rpm or more, providing the starch slurry onto the first facing material, depositing a gypsum slurry comprising stucco and water onto the starch slurry on the first facing material, providing a second facing material on the gypsum slurry, and allowing the stucco to convert to calcium sulfate dihydrate.

Gypsum panels and methods of making the same are provided herein. The gypsum panels include a barrier coating on a second surface of a coated fiberglass mat, the second surface comprising a coated surface, with the barrier coating comprising an acrylic binder and a filler in an amount of from about 50 to about 75 percent solids by volume of the barrier coating, the barrier coating being deposited in an amount of from about 46 lb/msf to about 60 lb/msf, dry weight. Sheathing systems of at least two such gypsum panels are also provided.

Disclosed are a composite gypsum board and a method of preparing composite gypsum board. The board contains a set gypsum core sandwiched between two cover sheets. The core is formed from a slurry containing stucco, water, and optional ingredients such as foaming agent, accelerator, retarder, polyphosphate, starch, and dispersant, and core intumescent material. The board also contains at least one skim coat and/or hard edges. A face skim coat layer can be included on one side of the core, facing a face cover sheet. A back skim coat layer can be included on the other side of the core, facing a back cover sheet. Hard edges are known in the art and can be formed, e.g., continuously from a stucco slurry for forming the face and/or back skim coats. Preferably, the back skim coat layer and/or the hard edges are formed from a slurry containing stucco, water, skim coat or edge intumescent material (which have the same desired characteristics), and other optional additives as desired. The skim coat or edge intumescent material can be composed of the same material as the core intumescent material, if desired, but the skim coat and/or edge intumescent material is present in a higher relative concentration in its respective slurry than the amount of core intumescent material in the core slurry. Examples of suitable intumescent materials include expandable vermiculite (e.g., No. 4 or No. 5 according to the US naming system, or combinations thereof), expandable graphite, perlite, or any combination thereof.

A gypsum tile backer panel with a pre-impregnated or pre-coated nonwoven fiber face mat. Methods for manufacturing these gypsum tile backer panel which include applying a gypsum slurry to a pre-impregnated or pre-coated nonwoven fiber face mat are also provided. A gypsum tile backer panel system employing the gypsum tile backer panel is also provided.

Gypsum panels and methods of making gypsum panels are provided. Methods of making gypsum panels include: depositing a first gypsum slurry onto a first surface of a first fiberglass mat; allowing the first gypsum slurry to set to form at least a portion of a gypsum core; and applying a substantially continuous barrier coating comprising a polymer binder to a second surface, opposite the first surface, of the first fiberglass mat, in an amount of from about 1 lb/MSF to about 40 lb/MSF, such that the substantially continuous barrier coating has an average thickness of from about 1 micron to about 100 microns, wherein the substantially continuous barrier coating eliminates at least 99 percent of pin holes present in the exposed second surface of the first fiberglass mat.

Methods of making gypsum panels, and the panels and systems of panels prepared by such methods are provide. The methods include forming a first gypsum slurry by combining stucco, water, and a siliconate and setting the first gypsum slurry to form at least part of a core of the gypsum panel.

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.