Abstract: A process for producing alpha-hemihydrate gypsum from dihydrate gypsum includes feeding a slurry comprising the dihydrate gypsum and water into a heating tube, heating the heating tube at a temperature effective to generate steam and pressure from the water, wherein the steam and pressure are effective to convert the dihydrate gypsum to the alpha-hemihydrate gypsum, and withdrawing the alpha-hemihydrate gypsum from the heating tube.

Abstract: A gypsum panel suitable for use in constructing a roof deck comprising a set gypsum core having at least about 0.3 pounds of reinforcing fibers per 100 square feet and a density sufficient to provide a board weight of 130 lbs per 100 square feet, where the core sandwiched between and faced with coated non-woven fibrous mats, wherein the free surface of each mat is pre-coated with a combination of a mineral pigment and a polymer latex adhesive binder applied to the mat surfaces as an aqueous coating composition.

Abstract: The present invention relates to a drywall tape or joint tape comprising a non-woven web of fibers having a coating of a filled, film-forming polymer on one side and being non-coated on an opposite side for covering seams or for repairs generally in connection with fiber mat-faced gypsum wallboard, and more particularly pertains to a method for finishing joint seams and making other repairs in connection with a coated fiber mat-faced gypsum wallboard.

Abstract: A fibrous mat faced gypsum panel having on at least one of the facing sheets a moisture resistant, cured coating of a radiation curable, e.g., UV curable, polymer.

Abstract: The present invention describes a fire resistant building material composition, useful for example as a fire door core and to a method of making this composition where the building material of the present invention is prepared from an aqueous slurry of calcined gypsum, paper fibers, a water insoluble organic binder, fiber reinforcement and a set retarder.

Abstract: The present invention describes a fire resistant building material composition, useful for example as a fire door core and to a method of making this composition. The building material of the present invention is prepared from an aqueous mixture of predominately expanded perlite, a small amount of a binder component consisting essentially of calcined gypsum and an organic binder, and optionally a fibrous reinforcement.

Abstract: The present invention describes an improved building material composition, useful for example as a fire door core. The building material of the present invention is prepared by compressing an aqueous mixture of expanded perlite and a fast setting, cementitious composition consisting essentially of a hydraulic cement, preferably Portland cement, and a pozzolan additive selected from the group consisting of metakaolin, VCAS and mixtures thereof, and preferably also includes an organic binder and a fibrous reinforcement.

Abstract: A cover stock supply system for continuously feeding cover stock to a wallboard production line includes: a plurality of cover stock cradles for receiving rolls of cover stock; a splicing table; a cover stock cutter disposed between the cover stock cradles and the splicing table. The cover stock cutter has a positioning loop around a cover stock feed path and a cutting cable attached to the positioning loop. Cutter is configured and adapted to rotatably deploy the cutting cable from the drawn position on a first side of the cover stock feed path to a re-set position on a second side of the cover stock feed path upon motion thereof around the cover stock feed path.