National Gypsum Company

Robert M Johnson

Elmer M Melling

Rodney A Stiling

Daniel A Winkowski

Edward A Burkard

Robert C Pomerhn

A process for making a cement and non-asbestos fiber mat on a Hatschek machine having a cylinder vat, a cylinder in the cylinder vat, and a porous surface on the cylinder on which the mat is formed and through which drainage water passes including the steps of introducing a slurry of cement and non-asbestos fibers and clay and poly(ethylene oxide) and water into the cylinder vat, and maintaining a lesser portion of the porous surface in engagement with the cement and non-asbestos slurry than the portion of the surface which is otherwise normally engaged by a cement and asbestos slurry of the same depth to thereby form the cement and non-asbestos fiber mat on the lesser portion of the porous surface and thus provide a lesser area for the slurry to drain than the area through which a cement and asbestos slurry drains, the poly(ethylene oxide) and clay causing the drainage water to be substantially clear and not to have any appreciable amount of cement fines, the cement and non-asbestos fiber mat containing Portland cement binder in the amount of between about 40% and 80% by weight, natural and/or synthetic fibers in an amount of between about 1% and 15% by weight, clay in an amount of between about 2% and 15% by weight, and poly(ethylene oxide) homopolymer in an amount of between about 0.03% and 0.5% by weight. The product may also contain silica and/or filler in an amount of between 10% and 40% by weight. The silica is generally used in a product which is to be autoclaved. The filler may be waste fiber-cement product or inert filler material.

Reinforced cement sheet product containing no asbestos for fabricating

Lightweight gypsum wallboard produced by continuously combining a small amount of surface active agent with a liquid stream, which stream is made up of substantially all of the water to be used in the manufacture of a continuous web of gypsum wallboard, passing this mixture through a long cylindrical static mixing tube filled with one inch ceramic saddles, while adding a controlled quantity of air thereto, then passing the mixture through a shorter cylindrical static mixing tube of equal diameter filled with 3/8 inch ceramic Raschig rings, forming a uniformly dispersed foam of very small bubbles from the liquid by completely generating all of the surface active agent therein to form this foam, and mixing this foamed liquid with finely ground dry calcined gypsum in a suitable mixing device to form a foamed settable gypsum slurry, disposing the slurry between paper cover sheets, and forming a continuous web of gypsum wallboard.

Foamed gypsum wallboard

A fiber-cement product which is capable of being formed on a Hatschek machine consisting essentially of a Portland cement binder in the amount of between about 40% and 80% by weight, natural and/or synthetic fibers in an amount of between about 1% and 15% by weight, clay in an amount of between about 2% and 15% by weight, and poly(ethylene oxide) homopolymer in an amount of between about 0.03% and 0.5% by weight. The product may also contain silica and/or filler in an amount of between 10% and 40% by weight. The silica is generally used in a product which is to be autoclaved. The filler may be waste fiber-cement product or inert filler material.

A cement-wollastonite product consisting essentially of Portland cement binder in an amount of between about 40% and 90% by weight, and wollastonite in an amount of between about 10% and 60% by weight. The product may contain fibers in an amount of between about 1% and 15% by weight. If the product contains fibers other than asbestos and is to be formed on a Hatschek or other type of wet forming machine, it may contain clay in an amount of between about 2% and 15% by weight, and poly(ethylene oxide) homopolymer in an amount of between about 0.03% and 0.5% by weight. The product may also contain silica and/or filler in an amount of between about 10% and 40% by weight for replacing part of the wollastonite. The filler may be waste fiber-cement product or inert filler material.

Reinforced cement sheet product containing wollastonite for reduced

A fiber cement product consisting essentially by weight of a Portland cement binder in the amount of between about 40% and 80%, natural and/or synthetic fibers in an amount of between 1% and 15%, clay in an amount of between about 2% and 15%, and thickener in an amount of between about 0.03% and 0.5%. The product may also contain silica and/or filler in an amount of between about 10% and 40% by weight. The silica is generally used in a product which is to be autoclaved. The filler may be waste fiber-cement product or inert filler material.

Reinforced cement sheet product containing fibers other than asbestos,

A predecorated printed paper on the gypsum wallboard with a clear washable coating over the printed paper, and having a thin coating of polyethylene emulsion on the back paper which overcomes the tendency of the coated predecorated paper to stick to the back paper of an adjacent board when the boards are piled in stacks for storage and shipment.

Block-resistant gypsum board

Lightweight gypsum wallboard produced by continuously combining a small amount of surface active agent with a liquid stream which stream is made up of substantially all of the liquids to be used in the manufacture of a continuous web of gypsum wallboard, subjecting this mixture to an intense agitation with vaned saw tooth-like rotary blades in a foam generator while adding a controlled quantity of air thereto, forming a uniformly dispersed foam of very small bubbles from the liquid by completely generating all of the surface active agent therein to form this foam, and mixing this foamed liquid with finely ground dry calcined gypsum in a suitable mixing device to form a foamed settable gypsum slurry, disposing the slurry between paper cover sheets, and forming a continuous web of gypsum wallboard.

An improved low density asbestos-cement product and the process whereby it is produced wherein an asphalt emulsion is combined with the formulation from which the product is made, which asphalt emulsion has an asphalt phase which asphalt has a softening point of at least 150.degree.F and is dispersed in water in globules all smaller than 10 microns.

Growing community of inventors

Kenmore, NY, United States of America

Robert M Johnson