Abstract: Fiberboards are provided containing at least about 65 wt. % calcium sulfate dihydrate derived from hemihydrate or anhydrous gypsum, and at least about 7 wt. % pulped paper fibers. The boards are capable of being formed into structural members having superior mechanical properties and/or fire resistance, including screw-holding capacities in excess of 650 lbs.

Abstract: Fiberboards are provided containing at least about 65 wt. % calcium sulfate dihydrate derived from hemihydrate or anhydrous gypsum, and at least about 7 wt. % pulped paper fibers. The boards are capable of being formed into structural members having superior mechanical properties and/or fire resistance, including screw-holding capacities in excess of 650 lbs.

Abstract: Fire-resistant structures are provided having at least a 20 minute ASTM E-152 fire test rating. The structures include glass partition walls having framing members formed from a gypsum-containing composition having a density of at least about 60 lbs/ft.sup.3, a flexural strength of at least 30 lbs (1/2 inch thick material), and a screw-holding capacity of at least about 400 lbs. The gypsum-containing composition further contains a substantially uniform distribution of solids including about 65 wt. % to about 90 wt. % set gypsum dihydrate, about 7 wt. % to about 30 wt. % paper fiber, and about 1.5 wt. % to about 35 wt. % of one or more performance boosters selected from inorganic fiber, clay, vermiculite, and binder polymer.

Abstract: Fiberboards are provided containing at least about 65 wt. % calcium sulfate dihydrate derived from hemihydrate or anhydrous gypsum, and at least about 7 wt. % pulped paper fibers. The boards are capable of being formed into structural members having superior mechanical properties and/or fire resistance, including screw-holding capacities in excess of 650 lbs.

Abstract: A continuous manufacturing line for preparing gypsum fiberboard is provided. The manufacturing line includes equipment for admixing hydratable gypsum, paper, and a quantity of water to form a substantially homogenous slurry, dewatering apparatus for removing a portion of the excess water from the slurry to produce a substantially continuous wet web, pressing equipment for configuring the wet web with a compression means to form a substantially continuous green board, a cutting station for cutting the substantially continuous green board into individual uncured lengths, and a heating station for curing the individual uncured lengths to form gypsum-dihydrate-containing fiberboards.

Abstract: Fire-resistant structures are provided having at least a 20 minute ASTM E-152 fire test rating. The structures include glass partition walls having framing members formed from a gypsum-containing composition having a density of at least about 60 lbs/ft.sup.3, a flexural strength of at least 30 lbs ( 1/2 inch thick material), and a screw-holding capacity of at least about 400 lbs. The gypsum-containing composition further contains a substantially uniform distribution of solids including about 65 wt.% to about 90 wt.% set gypsum dihydrate, about 7 wt.% to about 30 wt.% paper fiber, and about 1.5 wt.% to about 35 wt.% of one or more performance boosters selected from inorganic fiber, clay, vermiculite, and binder polymer.

Abstract: A door frame having excellent fire-resistance, flexural strength and screw holding properties is fabricated from gypsum fiberboard, specifically a gypsum fiberboard having a density of at least 60 lbs./cu.ft., a flexural strength of at least about 30 lbs. (1/2" thick material), and a screw holding capability of at least about 400 lbs. A preferred gypsum fiberboard material for fabrication of the door frame comprises a composition containing a substantially uniform dispersion of solids including by weight about 65% to 90% set gypsum, about 7% to about 30% pulped paper, up to about 9% binder, and about 0.8% to 2% inorganic fiber. A wood veneer is preferably applied to the visible faces of the gypsum fiberboard door frame members.

Abstract: Fire-resistant structures are provided having at least a 20 minute ASTM E-152 fire test rating. The structures include a core having a gypsum-containing composition and a density of at least about 60 lbs/ft, a flexural strength of at least 30 lbs (1/2 inch thick material), and a screw-holding capacity of at least about 400 lbs. The gypsum-containing composition further contains a substantially uniform distribution of solids including about 65 wt. % to about 90 wt. % set gypsum dihydrate, about 7 wt. % to about 30 wt. % paper fiber, and about 1.5 wt. % to about 35 wt. % of one or more performance boosters selected from inorganic fiber, clay, vermiculate, and binder polymer.

Abstract: Compositions containing nonfibrous calcium sulfate in hemi-hydrate or anhydrous form and fibrous additives, including paper fibers preferably derived from waste newspaper, capable of being formed into an unfaced building material having superior mechanical properties and/or fire resistance.

Abstract: Firedoor constructions manufactured from board compositions containing calcium sulfate in hemi-hydrate or anhydrous form and fibrous additives, including pulped paper fibers preferably derived from waste newspaper, capable of being formed into firedoor members having superior mechanical properties and/or fire resistance.

Abstract: Glass mat-faced gypsum boards having a set core containing gypsum dihydrate and at least a minimum amount of chopped fibers, as well as other optional fire-resistant additives, are provided. The resulting boards obtain superior fire resistance properties over conventional paper-faced boards of like thickness which include a similar amount of chopped glass fibers.

Abstract: A fire-resistant door comprises a core panel of mineral material, such as gypsum wallboard. A fiber mat, preferably comprising glass fibers, is at least partially embedded in each face of said core panel. An edge banding assembly disposed around the periphery of the core panel is centrally grooved to receive the panel edges. Facing sheets are affixed to the opposite sides of the edge banding assembly in spaced parallel relation to the core panel, and a spacer material at least partially fills the spaces between the facing sheets and the core panel.

Abstract: A fire-resistant article, for example, a fire door core comprising a major amount of expanded perlite in compressed form, an adhesive material, the major portion of which is starch, and preferably glass fibers, and a method for making the article by dry-mixing the ingredients substantially completely before water is added for the purpose of developing the adhesive characteristics of the starch.