Abstract: Disclosed are a composite gypsum board and a method of preparing composite gypsum board. The board contains set gypsum layers sandwiched between two cover sheets. The set gypsum layers are formed from at least stucco and water. The set gypsum layers include a board core and one or more skim coat layers. The set gypsum core makes up a substantial thickness (e.g., at least about 90%, at least about 92%, at least about 95%, or at least about 97%) of the total thickness of all the gypsum layers. A first skim coat layer is included on one side of the core, facing a first (face) cover sheet. A second skim coat layer is included on the other side of the core, facing a second (back) cover sheet. At least the second skim layer is formed from a slurry that contains starch. The stucco material generally includes a high salt impurity content, for example, when the stucco is calcined from certain sources of low-quality synthetic gypsum. For example, in some embodiments, the salts are chloride salts, e.g.

Abstract: A joint compound for use on joints between adjacent wall panels without the need for tape, the joint compound comprising a filler, a binder, carbon fibres and/or carbon nanotubes.

Abstract: A method of finishing an interior wall includes the steps of preparing a substrate of building panels comprising gypsum, cement or combinations thereof, said substrate having a surface, followed by applying a coating to the substrate, said coating comprising 1-30% by weight of a latex emulsion binder, 30-80% by weight calcium sulfate hemihydrate, up to about 8% by weight of a set inhibiting agent and 20-60% by weight water.

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: Methods and compositions that include a method of cementing comprising providing a cement composition comprising water, a hydraulic cement, and an additive comprising at least one additive selected from the group consisting of a stevia retarder and inulin; placing the cement composition in a subterranean formation; and permitting the cement composition to set in the formation.

Abstract: A gypsum slurry includes calcium sulfate hemihydrate, a set retarder in amounts of at least 0.15 lb/MSF, a set accelerator, water and aqueous foam. The set accelerator is selected to provide nucleation sites for crystallization of calcium sulfate dihydrate and is present in amounts of at least 5 Ib/MSF. The water to calcium sulfate hemihydrate ratio is at least 0.95. Further, aqueous foam is added in amounts sufficient to create a gypsum board having a dry density of about 29 to about 35 lbs/ft3.

Abstract: Method and apparatus for converting wet synthetic gypsum from a flue desulphurization process (FGD) to easily handled and metered briquettes by mixing a hydraulic additive such as by-pass dust from a cement kiln with synthetic gypsum and allowing the heat from the resulting hydraulic reaction to reduce the water content of the mixture to a formable consistency without adding external heat to the mixture as it is formed into briquettes.

Abstract: An example embodiment of a mixture to be employed in conjunction with water for preparing a slurry that hydrates to form a high strength flooring compound comprises about 50% to about 98% by weight calcium sulfate hemihydrate, about 0.002% to about 1% by weight polysaccharide, and about 0.02% to about 2.5% by weight of a lignosulfanate.

Abstract: A process for making calcined gypsum in slurry or powder form. The process includes adding at least two types of crystal modifiers to the slurry. The first crystal modifier is to control crystal morphology of the calcined gypsum (such as succinic and/or malic acid). The second crystal modifier is to prevent or retard setting to control set time (such as tetrasodium pyrophosphate (TSPP)) to form a water stable product. An accelerator is typically added at the site of use for specific applications such as setting type joint compound, media casting, exterior/interior coating, and sprayable fireproofing. A composition made by the process and a kit for using the composition are also disclosed.

Abstract: A flooring composition for mixing with water to produce a self-leveling slurry that quickly hydrates to form a high strength floor underlayment comprising a dry mixture of (1) beta gypsum produced by a continuous method; (2) Class C fly ash; (3) a conventional water reducing aid such as sulfonated melamines, sulfonated naphthalenes and their related formaldehyde condensates, and (4) a conventional set retarder.

Abstract: The present invention is based on solid-state reaction or reactions in the presence of small amounts of water, between phospho gypsum and agglutinating-neutralizing agents, principally though the application of oxy and hydroxy compounds, without discounting use of the respective carbonates of magnesium, aluminum and principally calcium, in addition to mixtures of these, and the subsequent preparation of self-hardening pellets which facilitate transport and handling. The technological process associated with the invention notably simplifies both the number and type of individual operations, and the preparation of pellets from mixtures of phosphor gypsum; it also reduces energy costs by operating at low temperatures (150°C.) during short periods (1-2 hours), while reducing the quantity of neutralizing agents, and minimizing the volume of water required for the process.

Abstract: Effective use of dispersants in wallboard containing foam results from a method where stucco is mixed with a first dispersant and a first quantity of water to form a gypsum slurry. A soap is blended with a second dispersant and a second quantity of water to make a foam. Subsequently, the foam is combined with the slurry. Choice of different first and second dispersants and their relative amounts allows control of the size distribution of the foam bubbles in the slurry and the resulting voids in the gypsum core. Use of the same dispersant in both the mixer and the foam water provides a boost in efficacy of the dispersant.

Abstract: A light-weight gypsum-based composition is provided which is particularly suitable for use in the production of wall panels. The composition comprises: (i) gypsum; (ii) glass, ceramic or polymer microspheres; and (iii) a coupling agent preferably selected from a silane or metal coupling agent. The resultant panel has good strength properties and has good performance with respect to nailability and cutability. Further, the paper backing commonly used on traditional commercial drywall panels can be optionally eliminated. The composition can also be cast into thicker products. A lightweight wall panel material is provided.

Abstract: A composition is disclosed for a mixture to be used in conjunction with water for preparing a slurry that hydrates to form a high strength flooring compound. The mixture includes from about 50% to about 98% by weight calcium sulfate hemihydrate. A three repeating unit polycarboxylate dispersant is included in the mixture in amounts from about 0.2% to about 10% by weight. The repeating units include a polyether repeating unit, an acrylic acid-type repeating unit and a maleic acid-type repeating unit. A modifier that enhances the efficacy of the dispersant is also a component of the mixture. When combined with recommended amounts of water, a slurry is formed that is useful as a flooring composition.

Abstract: Disclosed are concrete and fiber cement formulations and products comprising low-density calcium silicate hydrate, and methods for producing these formulations and products. The disclosed formulations exhibit accelerated curing times. Other advantages of the disclosed formulations include improved dimensional stability in extruded products, reduced cracking, and reduced wash-out in underwater applications. The products of the disclosed formulation have lower cost of production and faster time to market.

Abstract: 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.

Abstract: An injectable resorbable bone graft material, and methods of using the same, provide increased compressive strength after injection in a bone defect. The bone graft material is made from calcium sulfate hemihydrate having a thick stubby rod-like crystalline structure and low water-carrying capacity.

Abstract: A ready-mixed composition, which sets when mixed with an activator for the reaction of calcined gypsum with water to form set gypsum, is disclosed. The composition comprises water and calcined gypsum in a weight ratio of water to calcined gypsum of from about 0.15 to about 0.5, as well as a set preventer comprising a polyacrylic acid and/or a salt thereof. The composition has a viscosity of from about 5,000 centipoise to about 48,000 centipoise. Also disclosed is a kit that comprises separately packaged components. One of the components is a composition comprising calcined gypsum and a polyacrylic acid and/or a salt thereof, and, optionally, water. Another component of the kit comprises an activator which, when mixed with the composition, permits the composition to set.

Abstract: A ready-mixed composition, which sets when mixed with an activator for the reaction of calcined gypsum with water to form set gypsum, is disclosed. The composition comprises water and calcined gypsum in a weight ratio of water to calcined gypsum of from about 0.15 to about 0.5, as well as a set preventer comprising a polyacrylic acid and/or a salt thereof. The composition has a viscosity of from about 5,000 centipoise to about 48,000 centipoise. Also disclosed is a kit that comprises separately packaged components. One of the components is a composition comprising calcined gypsum and a polyacrylic acid and/or a salt thereof, and, optionally, water. Another component of the kit comprises an activator which, when mixed with the composition, permits the composition to set.

Abstract: A rough-surfaced substrate, such as a fiberboard, is provided with a smoother surface by applying a coating comprising calcium sulfate hemihydrate which has been prevented from hydrating to gypsum by set preventer, and which sets when brought into contact with a set initiator, e.g. aluminum sulfate, preferably present on the surface of the substrate.

Abstract: Gypsum plaster compositions with improved adhesion to plastic surfaces and metal surfaces comprise from 10 to 90% by weight of gypsum plaster, based on the total weight of the composition, and also, where appropriate, other additives, and a combination of: a) one or more water-redispersible polymer powders based on one or more vinyl ester, (meth)acrylate, vinylaromatic, olefin, 1,3-diene, or vinyl halides monomers, and optionally other monomers copolymerizable therewith; and b) one or more alkali metal and/or alkaline earth metal salts of short-chain fatty acids having from 1 to 4 carbon atoms in the hydrocarbon skeleton and from 1 to 4 carboxy groups, and which contain no OH groups.

Abstract: I provide a multi-part aqueous gypsum dental casting composition having gypsum and water and wherein (a) one or more of a first compound is mixed in the gypsum and/or water; or (b) one or more of the first compound and one or more of a second compound are mixed in the gypsum and/or water; or (c) one or more of the first compound and one or more of an acid are mixed in the gypsum and/or water; or (d) one or more of the first compound and one or more of the second compound and one or more of the acid are mixed in the gypsum and/or water; or (e) two or more of the acids and optionally one or more of the second compound are mixed in the gypsum and/or water; and (f) the gypsum and water are maintained separately and mixed when the casting is to be prepared. Also provided are the dosage sized containers for the above, along with the dosage size containers having gypsum enhancers.

Abstract: The invention provides a set gypsum-containing product having increased resistance to permanent deformation and a method for preparing it comprising forming a mixture of a calcium sulfate material, water, and an appropriate amount of one or more enhancing materials chosen from condensed phosphoric acids, each of which comprises 2 or more phosphoric acid units; and salts or ions of condensed phosphates, each of which comprises 2 or more phosphate units. The mixture is then maintained under conditions sufficient for the calcium sulfate material to form a set gypsum material.

Abstract: I provide a multi-part aqueous gypsum dental casting composition having gypsum and water and wherein (a) one or more of a first compound is mixed in the gypsum and/or water; or (b) one or more of the first compound and one or more of a second compound are mixed in the gypsum and/or water; or (c) one or more of the first compound and one or more of an acid are mixed in the gypsum and/or water; or (d) one or more of the first compound and one or more of the second compound and one or more of the acid are mixed in the gypsum and/or water; or (e) two or more of the acids and optionally one or more of the second compound are mixed in the gypsum and/or water; and (f) the gypsum and water are maintained separately and mixed when the casting is to be prepared. Also provided are the dosage sized containers for the above, along with the dosage size containers having gypsum enhancers.

Abstract: A set accelerator for at least one of accelerating the hydration rate and reducing the set time of an aqueous slurry of calcium sulfate hemihydrate is described. The set accelerator consists of a mixture of ground calcium sulfate dihydrate and zinc sulfate material. Aluminum sulfate material is an optional component of the set accelerator. The set accelerator is particularly useful in accelerating the hydration rates of sprayable plasters. A fluid form of the set accelerator may be made by suspending the solids in water. The fluid form is advantageously used in ready mixed setting type joint compounds.

Abstract: A multipart gypsum casting composition comprising a gypsum composition and a water composition where either the water and/or the gypsum composition contains at least two acids selected from the group consisting of oxalic acid, boric acid, phosphoric acid, citric acid, sodium citric acid, trisodium citric acid, tartaric acid, sulfuric acid, acetic acid, formic acid, malic acid, ascorbic acid and aspartic acid.

Abstract: The invention provides a set gypsum-containing product having increased resistance to permanent deformation and a method for preparing it comprising forming a mixture of a calcium sulfate material, water, and an appropriate amount of one or more enhancing materials chosen from condensed phosphoric acids, each of which comprises 2 or more phosphoric acid units; and salts or ions of condensed phosphates, each of which comprises 2 or more phosphate units. The mixture is then maintained under conditions sufficient for the calcium sulfate material to form a set gypsum material.

Abstract: An dispersant for plaster comprising a copolymer prepared by copolymerizing (a) a polyalkylene glycol monoester monomer having 2 to 300 mols of an oxyalkylene group(s) each having 2 to 3 carbon atoms, with (b) at least one monomer selected from among acrylic monomers, unsaturated dicarboxylic monomers and allylsulfonic monomers. When the dispersant of the present invention is used in preparing a plaster board, the foam stability is maintained so that the quality of the plaster board composition can be easily controlled.

Abstract: A method for the reversible agglomeration of fine particles of plaster of Paris (CaSO4.½H2O) and agglomerates made by the method which comprises agitating the fine particles in the presence of an organic polar liquid preferably nearly dry and having some ability to form hydrogen bonds (especially n-propanol) and then drying off most of the liquid whereby the fine particles spontaneously interlink (possibly by mechanical keying) in a way which allows the interlinks to be disrupted so as to release fine particles when the agglomerates are stirred into water by hand. Also a dry precursor mixture comprising the agglomerates containing conventional auxiliary additives for use in mixing with water to make aqueous compositions for use as filler pastes, casting materials or plaster slurries.

Abstract: The present invention is directed to blended hydraulic cement compositions which are formed with subbituminous fly ash. In one embodiment, the cement composition comprises from about 0.1 wt. % to about 7 wt. % of a retarding agent; from about 0.1 wt. % to about 4 wt. % potassium carbonate; from about 0.1 wt. % to about 4 wt. % citric acid; from about 0.1 wt. % to about 5 wt. % lithium carbonate; and from about 85 wt. % to about 99.7 wt. % of a subbituminous fly ash. In another embodiment, the cement composition comprises from about 0.1 wt. % to about 7 wt % of a retarding agent; from about 0.1 wt. % to about 6 wt. % of an alkali source selected from the group consisting of potassium carbonate, potassium hydroxide and blends thereof; from about 0.1 wt. % to about 4 wt. % citric acid; from about 0.1 wt. % to about 5 wt. % lithium carbonate; from about 25 wt. % to about 91.7 wt. % of a first subbituminous fly ash having a lime content; and from about 8 wt. % to about 60 wt.

Abstract: A curable gypsum-based composition for the production cured gypsum matrix. The composition comprises two-components, the first component includes calcined gypsum suspended in water, and a set retarding substance comprising (i) an organic acid containing at least two acid groups selected from the group consisting of carboxyl, sulphate, sulfonate, phosphate and phosphonate, the acid optionally also containing at least one hydroxy group per molecule; and/or (ii) inorganic anions selected from the group consisting of polyphosphate, polyborate and mixtures thereof. The second component comprises a set accelerating substance including water-soluble salts of multivalent metal ions. The water soluble salts in the second component form stable precipitates or complexes with the organic acid in the first component. The second component may also comprise easily soluble salts of ammonium and/or cations from the first group of the periodic table of the elements, which will accelerate the hardening process.

Abstract: Methods for making gypsum wallboard and for enhancing the compressive strength of wallboard by the addition of polymeric oxyalkylate viscosity modifiers are described. Preferred compounds are a copolymer comprising blocks of ethylene oxide and propylene oxide ether-linked to (1,2 ethandiyl dintrilo) tetrakis (propanol), an ethylene oxide/propylene oxide block copolymer and a polyethylene glycol polymer cross-linked with bisphenol A diglycidyl ether and combinations thereof.

Abstract: A method of preparation of gypsum wallboard, as well as a core composition suitable for use therein, are disclosed. The core composition includes a slurry of calcium sulfate hemihydrate (stucco), water, and calcium aluminum lignosulfonate and/or aluminum lignosulfonate.

Abstract: A method of controlling the ratio of hydration time (HT) to open time (OT) in the manufacture of composite materials from a mixture containing hydratable calcium sulphate such as gypsum binders, aggregates, fibers, water additives and other additives is disclosed. The method includes adding a retarder-accelerator combination such as Retardan and potassium sulphate to the mixture and applying pressure. The retarder-accelerator combination and application of pressure provide advantageous reduction in the ratio HT:OT. More particularly, HT:OT can be reduced to less than 1.

Abstract: A cementitious composition of the setting type which can be kept in a ready-mixed state and which can be caused to set and harden upon introduction of an accelerator with reproducibility and set time predictability. The cementitious base composition contains calcium sulfate hemihydrate as a principal filler material and certain non-calcium bearing phosphate additives which prevent setting action in the presence of water. An accelerator, such as zinc sulfate, may be added to the ready-mixed, cementitious composition to initiate the setting action, or the ready-mixed cementitious composition can be used as a drying type joint compound without the addition of an accelerator.

Abstract: A method of coating paper with a paper coating composition having a solids concentration of at least 45% by weight, consisting essentially of an aqueous cationic dispersion of a particulate calcium carbonate pigment and a nonionic or cationic adhesive, wherein the pigment has a particle size distribution such that no more than 1% by weight of the particles have an equivalent spherical diameter larger than 10 microns, at least 65% by weight of the particles have an equivalent spherical diameter smaller than 2 microns and not more than 10% by weight of the particles have an equivalent spherical diameter smaller than 0.25 micron, and wherein said pigment is dispersed with a combination of a cationic polyelectrolyte and an anionic polyelectrolyte, with the amount of cationic polyelectrolyte being in the range of about 0.01% to about 1.5% by weight, based on the weight of the dry pigment, and with the amount of anionic polyelectrolyte being in the range of about 0.01% to about 0.5% by weight.

Abstract: Setting and hardening accelerating agent for siliceous hydraulic binders wherein: a) it is obtained by hydration, in the usual pressure and temperature conditions, and grinding of a siliceous hydraulic binder aqueous suspension; b) the suspension particles are sufficiently fine for the agent to meet the following test requirements: an aqueous suspension in a sedimentation specimen at 20.degree. C., containing 10 grams (dry weight) of the accelerating agent in 100 ml of water, must have a sedimentation deposit height at least equal to 50% of the initial height at the end of two days; c) it is in the form of an aqueous suspension.

Abstract: The present invention provides a filler for wood products, especially those intended for indoor use, This filler can include a putty including a mixture of calcium sulphate and calcium oxide (or a compound forming calcium oxide when heated); at least one mineral pigment; and an agent for retarding the setting of the putty. The invention also contemplates a method for filling wood products. In accordance with this method, one fills an orifice within the wood product with a filler which includes a putty including a mixture of calcium sulphate and calcium oxide (or a compound forming calcium oxide when heated); and at least one mineral pigment. The filler is then smoothed and a surface of the filled wood product is finished.

Abstract: A set control composition and/or interground blend of materials including a calcium sulfate material and magnesium sulfate.

Abstract: The invention provides a method of making gypsum products such as plasterboard from foamed gypsum plaster slurry. The method uses a first mixing chamber 10 containing a high speed rotor 14 and inlets 18, 19 for gypsum plaster and water. The initial dispersion of gypsum plaster and water foamed in the first chamber passes directly and continuously into a second chamber 25 containing a low speed rotor 29. Preformed foam is introduced into the second chamber through an inlet 33, and the foamed slurry product leaves the second chamber through an outlet 34, to be formed into plasterboard.

Abstract: The present invention provides improved cementitious compositions which can include drilling fluid as a component thereof and methods of cementing wells utilizing such compositions. The compositions are basically comprised of a cementitious material, water, a hardenable resinous material and optionally, drilling fluid in an amount up to about 70% by volume of the cementitious material in the composition.

Abstract: A veneer plaster having strengths of substantially greater than 3,000 psi, abrasion resistance of penetrations less than 0.04 inch with 1,000 cycles of a five-pound brush using a 3M Granule Embedding Testing Machine, made from about 1,800 pounds of calcium sulfate beta hemihydrate, 200 pounds of fine silica sand, and about 4 pounds of a fine, white powder dispersant typified by a melamine-formaldehyde-sodium bisulfite polymer.

Abstract: Binder compositions are provided which are principally composed of a lime-containing flyash, and optionally hydratable gypsum, with a small amount of a property improving additive. The compositions are capable of setting when mixed with sufficient water to form a hardened material having a high degree of compressive strength after only about 1 hour following set. In selected embodiments, compositions are provided for floor underlayment, road patch and exterior statuary applications. Compressive strengths starting at about 600 psi can be achieved within 1 hour after set with adequate working time for construction applications.

Abstract: The water resistance of gypsum compositions, such as those used in gypsum wallboard, is improved by incorporating in the compositions an aqueous emulsion containing a paraffinic hydrocarbon having a melting point of 40.degree. to 80.degree. C., montan wax and polyvinyl alcohol.

Abstract: The invention relates to a gypsum-based cementitious composition capable of upon mixing with fine aggregate in a weight ratio to said gypsum-based cementitious composition of from about 1.25:1 to 2.5:1; and sufficient water to provide a pumpable, self-leveling wet gypsum-based cementitious composition having a flowability such that the wet gypsum-based cementitious composition completely self-levels to produce a topographically smooth surface without floating or finishing, providing, upon hardening, a sub-floor resistant to delamination from its substrate having a dust-free surface and compressive strength in the range of about 2500 to 6000 psi. The invention further relates to methods for making floor underlayments using these compositions, and for making the compositions.

Abstract: Sprayable fireproofing compositions for structural members such as steel columns are provided, as well as a method of applying multiple coatings thereof. The compositions comprise a Portland cement-based material, stucco, a high density aggregate and an accelerator. The compositions eliminate the long setting times typical of Portland cement-based materials, and improve the hangability thereof. The product is produced by dry blending a mixture of Portland cement, a high density aggreagte, stucco (calcium sulfate hemi-hydrate) and optionally, a stucco set retarder and shredded polystyrene aggregate. Upon the addition of water, sprayable slurries are formed which can be pumped to the point of application. An accelerator is added in close proximity to the point of injection. The slurries adhere to the structural member in the slurried state and after setting to provide excellent fire and heat protection.

Abstract: An injection product for fine sands and other porous matter. This product comprises, on the one hand, cement and an alkaline silicate and, on the other hand, an agent inhibiting the reaction between the above two constituents. Application is in the field of construction.

Abstract: New set-accelerating admixtures for hydraulic cement compositions are disclosed. These admixtures incorporate known set accelerators and certain low molecular weight glycols, e.g., glycerol and ethylene glycol, are found to be surprisingly effective in decreasing the initial set time of hydraulic cements, mortars, and concretes, and are advantageous as reduced-temperature set-accelerators.

Abstract: Sprayable fireproofing compositions for structural members such as steel columns are provided, as well as a method of applying multiple coatings thereof. The compositions comprise a Portland cement-based material, stucco, and an accelerator. The compositions eliminate the long setting times typical of Portland cement-based materials, and improve the hangability thereof. The product is produced by dry blending a mixture of Portland cement, stucco (calcium sulfate hemi-hydrate) and optionally, a stucco set retarder and shredded polystyrene aggregate. Upon the addition of water, sprayable slurries are formed which can be pumped to the point of application. An accelerator is added in close proximity to the point of injection. Other additives may also be included, such as starch, adhesives and cement strength enhancers. The slurries adhere to the structural member in the slurried state and after setting to provide excellent fire and heat protection.

Abstract: An oil and gas well cementing composition and method is shown utilizing hydraulic cement, water and an additive having pendant phosphonate groups on a polymeric backbone. The additive provides improved fluid loss and settling characteristics while maintaining desirable viscosity and setting time characteristics. Pendant phosphonate groups are added to the polymer by adding about 0.2% to about 10.0% by weight phosphonic acid either during or after polymerization.