Abstract: Production of plasterboard includes spreading of a mixture formed of gyps fibers and water onto a continuously moving belt to form a spread layer subsequently precompressed to 110% to 180% of a final board thickness and successively wetted from both sides and thereafter compressing the wetted layer to the final board thickness.

Abstract: Process and apparatus for the continuous production of gypsum fiber plates in which the fiber component is dewatered and rediluted with water recovered from the gypsum-fiber suspension after it has been spread on a belt, passed over at least two suction boxes and densified on the last suction box by a densifying device engaging the filter cake layer from the top.

Abstract: Deinking by-product from wastepaper recycling operations and pulp mill clarifier sludge are incorporated into drywall or other gypsum-based building products, such as building blocks. The deinking by-product or pulp mill clarifier sludge is diluted and mixed with stucco (calcium sulfate hemihydrate). The resulting slurry preferably is subjected to an initial dewatering, following the on-set of hardening of the gypsum, and drywall or other building product is formed from the dewatered material. A significant loading of fibrous material in the drywall sheet or other gypsum product is achieved using the procedure, imparting improved flexural strength to the product. The preferred procedure also may be used to incorporate virgin or recycled wood pulp into the building product.

Abstract: A foaming agent having improved foaming performance comprised of a mixture of alkyl sulfates and alkyl ether sulfates which have the general formula: R (CH.sub.2 CH.sub.2 O).sub.y --SO.sub.

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: A method of, and compositions for, the making of a fire-resistant door core assembly. Doors produced from the door core assemblies. In the making of a door core assembly, an aqueous slurry containing gypsum cement and diatomaceous earth is prepared. The slurry may also include expanded mineral ore material and Portland cement. The slurry preliminarily hardens during a green cure stage.

Abstract: Plasterboard is made by first spreading a mixture of plaster, fibers and er and then pressing this moist mixture to form the raw board. The upper and lower surfaces of the raw board are then wetted and the thus wetted raw board is pressed with a pressure less than the original consolidation pressure.

Abstract: A flame resistant to nonflammable composite panel is produced from a nonextrudable core mixture with a pourable, nonflammable filling material and a binder, and on both sides cover strips flexibly bonded to the core. For a continuous production of the composite panel in one operation, the core mixture is poured onto an inrunning lower cover strip, in contact with a lower adhesive film facing the core mixture, and a pile is formed there, extending over the entire width of the adhesive film, both continuously and uniformly drawn through a V gap and compacted there for the first time and calibrated to thickness, an upper adhesive film, upwardly limiting the precompacted core mixture, is fed in and brought into contact with a continuously fed cover strip and the sandwich is pressed with further compaction, heated, cooled and cut to the final length of the composite panel.

Abstract: A foaming agent having improved foaming performance comprised of a mixture of alkyl sulfates and alkyl ether sulfates which have the general formula: R (CH.sub.2 CH.sub.2 O).sub.y --SO.sub.

Abstract: A lay-in ceiling panel structure, comprising a glass fiber ply, a gypsum board, and a highly perforated vinyl lamina. The ceiling panel structure having noise and sound transmission reduction coefficients in the range of 0.85 to 0.95 sabins and 0.35 to 0.39 dbs respectively. This structure also provides good fire resistance, space efficiency, and a lower surface that is washable and pleasing to the eye. In addition, the glass fiber ply is secured to the gypsum board by droplets of glue which are spaced 1 to 2 inches apart and which are applied 4 to 6 inches away from the outer periphery of the gypsum board. Applying the glue in this way allows the glass fiber ply and vinyl lamina to lay flat even if the board is warped by water leaks, humidity or age.

Abstract: Geopolymer-modified gypsum construction materials. Compositions derived from combining geopolymer adhesives with conventional gypsum wallboard slurry formulations produce an interpenetrating network (IPN) which cures by loss of process water to a refractory solid having improved fire and water resistance. Geopolymer adhesive starting compositions includes soluble and insoluble silicates, buffers and salts, and a chemical setting agent in aqueous suspension.

Abstract: Narrow range alkoxylated alcohols are sulfonated and used as improved foaming agent compositions. These compositions exhibit desirable foaming characteristics for use in the manufacture of gypsum board and concrete and in oil field applications.

Abstract: A method for reducing the consistency of a water and gypsum stucco slurry comprising admixing water, stucco, and an additive, the additive in an amount effective to reduce the consistency of the admixed slurry as compared to a slurry containing only water and stucco, and the additive selected from the group consisting of one or more polyalkylene polyamines having a molecular weight below 1,000.

Abstract: A method for incorporating siloxane into a water-resistant, gypsum-based article is disclosed, comprising, (A) adding said siloxane to water; (B) mixing said siloxane/water mixture with calcined gypsum to form an aqueous slurry; and (C) allowing said slurry to set to form a set gypsum-based, water-resistant article.

Abstract: Paper or cellulose pieces forming a fiber raw material are wetted with water prior to comminution so that the comminution into fibers is effected with the moistened raw material. The moisture content of the fibers makes up at least part of the water of hydration required to completely set the binder which is mixed with the fibers. The binder can be plaster (gypsum) or hydraulic cement. The mixture is pressed to the desired shape and heat may be applied.

Abstract: In the improved gypsum board in accordance with this invention, the board has a gypsum core and first and second cover sheets of fibrous material on opposing faces. The core has a first stratum parallel to and adjacent the first cover sheet. This stratum does not contain any fibers of the fibrous material. This first stratum has relatively few voids and a substantially greater density than the central portion of the core of the board. The central portion of the core has a plurality of relatively large discrete voids substantially uniformly distributed throughout the central portion of the core. These voids have substantially spherical coherent walls.

Abstract: A moist mixture of plaster of Paris and fibres is produced due to the fact that before mixing with the fibres, a considerable quantity of water is supplied to the plaster of Paris, which leads to a moisture content of the plaster of Paris of up to 22% by weight (with respect to the dry substance). With this moisture content, the plaster of Paris is indeed no longer stable in storage in an unrestricted manner; however, it remains free from lumps for a certain processing time and can be mixed with the fibres in a high speed, continuous mixer. The moist mixture of plaster of Paris and fibres obtained in this way is intended as an initial product in the manufacture of fibre-reinforced moulded plaster bodies, in particular of fibre-reinforced plaster boards. It contains the water necessary fort setting in the most homogeneous distribution and in a precise dose (FIG. 1).

Abstract: A mixture of waste, essentially cellulosic material and a fire proofing solution can be used to make building materials with exceptional qualities. These qualities include fire proofing, vermin proofing, water proofing and excellent insulative values, for example. Additionally, this process represents an excellent method for recycle of these waste materials. A sheetrock-like or wall-board material can be made therefrom, one which can be nailed, screwed, drilled and fastened without causing serious damage to the surface or the element itself.

Abstract: A continuous process for the production of gypsum board of variable yet predictable density, wherein a fibrous from of stucco produced from gypsum crystals or fibers is combined with standard calcined gypsum and formed into the board. The density of the resultant board varies inversely with the content of fibrous stucco. The process yields lightweight boards suitable as standard wallboards and inorganic insulating boards.

Abstract: A method and apparatus for continuously producing molded member, especially sheets, from a mixture of gypsum and fibrous material. In a first mixing stage, measured-out quantities of gypsum and fibrous material are thoroughly mixed together, with the dry mixture being weighed and subsequently moistened in a second mixing stage by supplying water thereto in conformity to the weight of the dry mixture. The moistened mixture is subsequently dispersed onto a support to form molded members, with the surface of each molded member being additionally moistened, and the latter then being compacted. To achieve higher strength, the mas flow of the gypsum/fibrous material mixture is divided into independent partial mass flows that are dispersed in layers to form the multi-layer molded member, with each partial mass flow forming one of the layers of the molded member.

Abstract: This invention relates to a method of joining two or more surfaces together by applying to at least one of the surfaces a water-based adhesive or an adhesive which liberates water during curing, and generating salt during the course of the joining operation, which salt will bind water that is present during the joining as water of crystallization.

Abstract: A gypsum mold having good water absorbing properties, which is suitable for cast molding pottery, can be prepared by stirring a mixture of hemihydrate gypsum cooled to -40.degree. to 5.degree. C. and water to form a slurry of gypsum in water having a temperature of -5.degree. to 10.degree. C., pouring it into a water-impermeable mold, maintaining it therein until the setting reaction thereof is completed and then releasing the set product from the mold.

Abstract: A method for the production of fibrous plaster boards for which a suspension is prepared from wet-digested fiber material and calcium sulfate dihydrate, the suspension is formed into a board with removal of water, and the dihydrate is recrystallized with heating at atmospheric pressure to a hemihydrate which is subsequently converted back into the dihydrate by the addition of water. For this purpose, the suspension is dewatered from a water content of about 300 to 600% to one of about 30 to 40% in dewatering equipment, the dihydrate is recrystallized in air and without pressure to the beta form of the hemihydrate and the water, required for setting, is aspirated through the board by suction.

Abstract: An exterior finishing system for a building. including particularly an exterior insulation system, which includes a fibrous mat-faced gypsum board, preferably a board in which the set gypsum core thereof is water resistant, and preferably one in which the set gypsum core is sandwiched between two sheets of porous glass mat, with the outer surface of at least one of said mats being substantially free of set gypsum, and means for preparing the board, including control of the viscosity of the aqueous gypsum slurry from which the set gypsum core of the board is formed. Also, the use of fibrous mat-faced gypsum board as the shaft liner panel in a shaft wall assembly.

Abstract: The invention relates to a method for continuous manufacture of materials, specially material slabs, from mixtures of binders, reinforcing agents, and possibly additives, the mixtures being cured by hydrate formation and being of a pourable or spreadable consistency. The special properties and usability of the materials are achieved by a permanent and irreversible compression of the initially-formed structure, whereby an extruded slab is formed from the mixture, then compressed and calibrated. The extruded slab is first compressed in a compression phase at a pressure which is sufficiently high that the slab's thickness after compression is less than the specified value of the finished extruded slab, and its density specified final density, the resulting values of density and degree of compression being sufficiently high that the compressed extruded slab is calibratable immediately thereafter in a calibration phase without the active application of pressure.

Abstract: A decorative tile having a front face with a design thereon varies in density so that the front face of the tile presents a solid appearance, but the overall weight of the tile is less than for a comparable conventional plaster tile. The tile of the invention can be made from a mixture including a binder, fiber strands, and a bulk enhancing agent. The decorative tile of this invention is particularly useful for ceiling decoration.

Abstract: A gypsum plaster and chopped glass fiber tile having increased insulation values, reduced weight and reduced density due to the presence of vermiculite and perlite.

Abstract: A setting accelerator for calcined gypsum plaster and a process for its preparation are disclosed. The accelerator comprises finely ground calcium sulfate dihydrate having composite coatings on the particles of firstly a calcination inhibiting material such as sugar and secondly a coating of aluminum sulfate hydrate. The accelerator is particularly useful in the formation of gypsum wallboard.

Abstract: The sodium and/or ammonium salts of a mixture of n-alkyl oxyethylated sulfuric acids in aqueous solution, wherein all the compounds have the same molecular formula CH.sub.3 (CH.sub.2).sub.x CH.sub.2 (OCH.sub.2 CH.sub.2).sub.y OSO.sub.3 .sup.- M.sup.+ being either the sodium or ammonium cation, x being an integer from about 6 to 12, and y being an integer from about 1 to 3.5, a major portion of the mixture comprising compounds where x equals 6-8 and a minor portion of the mixture comprising compounds where x equals 10-12; these mixtures being capable of generating foam of relatively large volume and high stability.

Abstract: The sodium and/or ammonium salts of a mixture of n-alkyl oxyethylated sulfuric acids in aqueous solution, wherein all the compounds have the same molecular formula CH.sub.3 (CH.sub.2).sub.x CH.sub.2 (OCH.sub.2 CH.sub.2).sub.y OSO.sub.3.sup.- M.sup.+, M.sup.+ being either the sodium or ammonium cation, x being an integer from about 6 to 12, and y being an integer from about 1 to 3.5, a major portion of the mixture comprising compounds where x equals 6-8 and a minor portion of the mixture comprising compounds where x equals 10-12; these mixtures being capable of generating foam of relatively large volume and high stability.

Abstract: A novel process for producing a non-combustible gypsum board and a non-combustible laminated gypsum board having superior practical physical properties, smoothly and efficiently is provided, which process is characterized by preparing a mixture consisting of a powdery gypsum consisting of 50 to 95 parts by weight of a hydrating gypsum and 5 to 50 parts by weight of gypsum dihydrate, a definite amount of fibers and a definite amount of a caking retarder and a necessary amount of water; molding the mixture before the hydrating gypsum is hydrated; and setting and drying the resulting molded material.

Abstract: The invention provides an installation and method for the continuous production of materials using exothermically hardening binders, such as gypsum or cement, comprising a mixing and feeding station and a calibrating unit or press and also a control system for operating the installation.

Abstract: The sodium and/or ammonium salts of a mixture of n-alkyl oxyethylated sulfuric acids in aqueous solution, wherein all the compounds have the same molecular formula CH.sub.3 (CH.sub.2).sub.x (OCH.sub.2 CH.sub.2).sub.y OSO.sub.3.sup.- M.sup.+, M.sup.+ being either the sodium or ammonium cation, x being an integer from about 6 to 12, and y being an integer from about 1 to 3.5, a major portion of the mixture comprising compounds where x equals 6-8 and a minor portion of the mixture comprising compounds where x equals 10-12; these mixtures being capable of generating foam of relatively large volume and high stability.

Abstract: A method of manufacturing acoustic panels comprising the steps of pouring a solidifiable liquid into a container, placing a porous layer of material onto the solidifiable liquid, solidifying the solidifiable liquid into a rigid layer, and removing the rigid layer and the porous layer from the container. The container has at least one form member extending from the bottom of the container upwardly. This form member extends upwardly into the porous layer. The solidifiable liquid is a slurry of cement. The container and the form member are magnetically attractive. The form member has a generally tapered cylindrical shape and rounded edges. The porous layer is a fibrous material.

Abstract: Blown mineral wool fibers are introduced into slurries (such as gypsum board core formulations and steel column fireproofing plaster formulations) by first blending and coating the blown mineral wool with a powdered calcium sulfate to produce a light, open nodulated effect. When mixed into aqueous calcined gypsum slurries, the nodules open up, thoroughly dispersing the mineral wool--calcium sulfate blend in the aqueous slurry and contributing fire resistant properties to the set gypsum product.

Abstract: Described is a novel gypsum board and a manufacturing method therefor by first forming a particulate layer securely adhered to the base paper for the gypsum board and by utilizing an adhesion layer which has been formed by the reaction of the particulate layer for pasting the gypsum core material on the base paper for board, so that adhesion between the core material and the base paper is enhanced as well as the strength of the gypsum board itself is improved.

Abstract: An improved sizing is feasible by adding into a papermaking pulp slurry an aqueous dispersion prepared by mixing an aqueous solution of an ampholytic acrylamide polymer having both cationic and anionic groups with a liquid substituted succinic anhydride or with an anhydrous liquid mixture of a liquid substituted succinic anhydride and an oil-in-water type surfactant. Such a paper sizing process is very useful for making plasterboard base paper of multilayered structure composed of at least one surface layer having a high hot water resistance and at least one back layer having a good adhesiveness to plaster slush.

Abstract: Disclosed is a process for the preparation of an electron beam curing gypsum panel which comprises subjecting a hydrated gypsum slurry containing or free of an additive, fibrous material, fine aggregates, water, etc. to defoaming, setting and drying to form a gypsum substrate, coating an electron beam curing resin composition on the surface of the gypsum substrate to form a coated film, and irradiating accelerated electron beam on the coated film thereby to be cured.

Abstract: By-product gypsum, which is formed during a flue gas desulfurization process, (FGD gypsum) is carefully formed as an aqueous slurry of crystals having a mean particle diameter of between about 35 microns and 80 microns and filtered, which filter cake is substantially completely dried before calcination, without any substantial grinding action, the crystals are then flash calcined to a hemihydrate, then ground, to reduce consistency, and then formed into an aqueous slurry from which a paper-covered gypsum board is formed of superior core quality.

Abstract: Mortar is deflected continuously onto a moving carrier sheet from a distributor belt which is moving transversely to the carrier sheet by a plow which shuttles across the length of the distributor belt. An uninterrupted flow of mortar is spread across the sheet. The layer of mortar on the carrier sheet is slightly undulatory in the machine direction but a lateral cross section has a substantially uniform thickness so that a flat broad ribbon of mortar emerges from under a screed downstream from the shuttle plow.

Abstract: A composite paper particularly adapted for use as cover sheets in the production of gypsum wallboard, the paper being sufficiently porous to permit better drainage and more rapid drying in the production of the paper, and when applied to the surfaces of a gypsum slurry for forming wallboard, permits less heat to be utilized in the wallboard conversion, thereby saving energy in the board production required for drying the board. The paper comprises in weight percent:(A) cellulosic fibers in an amount of from about 65% to about 90% and preferably having a fiber freeness of from about 300 ml to about 550 ml Canadian Standard Freeness,(B) calcium sulfate as a filler in an amount of from about 10% to about 35%,(C) a binder in an amount from about 1% to about 31/2%,(D) a flocculant in an amount of from about 0.1% to about 0.2%,(E) a buffering agent in an amount from about 0.

Abstract: A gypsum board consisting essentially of a monolithic cellular core of set gypsum and a fiberous cover sheet encasement provided with improved properties by the gypsum core having incorporated therein coal fly ash in an amount of about 1-20% by weight of stucco in the gypsum slurry used in forming the board and method of producing the board are disclosed.

Abstract: A method of producing a gypsum plaster board. This method includes a step of preparing a starch paste which is effective to bond the gypsum core member and both paper boards. In this step, first, about 10-30 wt % of starch such as corn starch based on water is added to water and mixed to obtain milk of starch. Next, about 0.1-1.5 wt % of amylolytic enzyme such as .alpha.-amylase based on the starch is added and then heated to the decomposition point of the starch with stirring. After the heating is stopped at the range of DH 0.1-10, about 0.8-1.0 wt % of an enzyme deactivating agent based on the starch is added and mixed with water to prepare a starch paste. After the starch paste being prepared by the aforementioned process, a raw material of the gypsum core member, that is, calcined gypsum, reinforcing agent such as glass fiber, weight reducing agent such as surface active agent and the starch paste are mixed with water to obtain gypsum slurry.

Abstract: A process for producing a healed stucco of low water demand is disclosed in which calcined gypsum is treated with an aqueous solution of a gypsum solubilizing agent, preferably in an impacting blender while grinding the calcined gypsum to increase its surface area. The product can be dried for storage or sent directly to forming gypsum board.

Abstract: A method of making gypsum wallboard in which a portion of the conventional foamed gypsum slurry for forming the wallboard core is fed through a relatively high speed agitator, wherein a special addition of material is thoroughly admixed therewith to increase the fluidity without adversely affecting the density or setting characteristics and this portion of the slurry is then disposed along the edge portion of the wallboard being formed, whereby a hard-edge wallboard is produced under conditions including improved uniformity of core edge setting time, density and dimensions and reduced plug-ups of feed lines through which the core-edge material is fed.

Abstract: A process for the whitening of phosphogypsum comprising treating a phosphogypsum in aqueous suspension with an amount of ozone equal to at least 150 parts by weight per million parts by weight of phosphogypsum calculated as Ca SO.sub.4.2H.sub.2 O, the pH of the aqueous suspension being lower than or equal to 3, to yield a whiteness grade of phosphogypsum higher than 75, according to French Standard NF Q 03-038.

Abstract: This invention provides a process of producing a building product, particularly a gypsum slab having preferably a density of below 800 kg/m.sup.3, with gypsum and mixing water. The quantity of mixing water required for rehydration and molding is at least substantially completely introduced into the gypsum by means of water saturated porous particles added in a distributed form. The process comprises the steps of intimately mixing water saturated particles with pulverous gypsum to form a fluid mixture; converting said fluid mixture at least almost completely without the application of pressure to the shape of a gypsum building product; permitting mixing water of the water saturated particles to be absorbed by the pulverous gypsum, and permitting the resulting mixture to set and harden.

Abstract: Essentially nonflammable, moldable, strong laminates formed of alternating layers of cured magnesium oxycement and a fibrous web, e.g., paper formed of cellulosic, glass or synthetic resin fibers or mixtures thereof. The magnesium oxycement may contain a suitable filter, the surfaces of the laminate may be modified and composites may be formed with a wide variety of core materials. The laminates are made by coating the fibrous webs with a reactive slurry of a magnesium salt solution and magnesium oxide. The fibrous web materials used are impermeable to the extent that no appreciable amount of the magnesium salt solution is absorbed and no appreciable amount of the magnesium oxide is filtered out onto the surface or into the intertices of the web.

Abstract: Blocks or panels 10, more especially of porous or cellular structure, are faced with a fabric or web inorganic fibres, preferably in the form of glass fibre tissue, bonded to the block or panel by a composition 14 of thermosetting condensation polymer and gypsum, preferably in a ratio between 1:1.6 and 1:4.0. The amount of the composition is preferably such as to provide a film of minimal thickness over the surface of the fabric or web, corresponding to a glass: resin plus gypsum proportion of 8 to 25%. Such coatings when applied to foamed plastics, chip-board or glass fibre panels provide boards suitable for ceilings or partitions and having ample strength and flame resistance. The blocks or panels may be made continuously by applying fibrous tissues, impregnated with a fluid mixture of plaster and resin by roller spreaders, to the face of panel elements supported between release sheets, for example of polypropylene. Pressure may be applied and maintained, if desired, until the fluid mixture has set.

Abstract: Reinforced facings, including reinforcing webs entrained in hydraulic cement via a slurry bath, adhere to a nailable lightweight aggregate cementitious core to form a panel web. The reinforced web is formed on abutting conveyed carrier sheets, and the web is transversely cut, between the sheets, while moving or when stopped, in response to sensing of the sheets. The cut panels, on respective sheets are stacked for curing without damaging the panel edges and in a manner to minimize panel flex. Slurry bath, facing applicators, and cutter and stacking apparatus are included.