摘要:
An improved gypsum slurry that includes water, calcium sulfate hemihydrate, a polycarboxylate dispersant and a modifier. The modifier is chemically configured to improve the efficacy of the polycarboxylate dispersant. Preferred modifiers include cement, lime, slaked lime, soda ash, carbonates, silicates and phosphates.
摘要:
The invention generally provides gypsum-containing slurries including stucco, trimetaphosphate salt, and naphthalenesulfonate dispersant, wherein the trimetaphosphate salt is present in an amount of at least about 0.12% by weight based on the weight of stucco. Other slurry additives can include accelerators, binders, starch, and paper fiber, glass fiber, and other known ingredients. The invention also comprises the gypsum-containing products made with such slurries, for example, gypsum wallboard, and a method of making gypsum wallboard.
摘要:
A gypsum slurry includes water, a hydraulic component including stucco and a polycarboxylate dispersant. The dispersant has two repeating units wherein the first repeating unit is an olefinic unsaturated mono-carboxylic acid repeating unit or an ester or salt, and the second repeating unit is a vinyl or allyl group bound to a polyether by an ether linkage. The slurry can be made into a gypsum panel.
摘要:
A composition and method for treating a set gypsum-containing material are disclosed. The composition is formed from at least water at least one trimetaphosphate salt, at least one monobasic phosphate salt, and at least one acyclic polyphosphate salt having at least three phosphate units. The method comprises applying to a set gypsum material at least two of the following inorganic phosphates: at least one monobasic phosphate salt, at least one trimetaphosphate salt, and at least one acyclic polyphosphate salt having at least three phosphate units. The method can be for inhibiting re-calcination of a set gypsum containing material, and/or for enhancing the strength, surface hardness, paintability, abrasion resistance, and/or water erosion resistance of a set gypsum-containing material. Also disclosed is a method of making a set gypsum-containing material.
摘要:
A cementitious article and a method of making a cementitious article are disclosed. The cementitious article comprises a cementitious component that comprises a polyvinyl acetate type polymer, a monobasic phosphate, and optionally boric acid. Cementitious articles, such as board, are prepared such that the polyvinyl acetate type polymer, the monobasic phosphate, and optionally boric acid can be present in the cementitious core, and/or in dense layers if present. The concentration of the polyvinyl acetate type polymer, monobasic phosphate, and optionally boric acid in the cementitious article can increase from a central region A to peripheral regions B and C, respectively. In some embodiments, the polyvinyl acetate type polymer is a polyvinyl alcohol and the monobasic phosphate is monoammonium phosphate.
摘要:
Polymerization of siloxane is improved using a gypsum-based slurry that includes stucco, Class C fly ash, magnesium oxide and an emulsion of siloxane and water. This slurry is used in a method of making water-resistant gypsum articles that includes making an emulsion of siloxane and water, then combining the slurry with a dry mixture of stucco, magnesium oxide and Class C fly ash. The slurry is then shaped as desired and the stucco is allowed to set and the siloxane polymerizes.The resulting product is useful for making a water-resistant gypsum panel having a core that includes interwoven matrices of calcium sulfate dihydrate crystals and a silicone resin, where the interwoven matrices have dispersed throughout them a catalyst comprising magnesium oxide and components from a Class C fly ash.
摘要:
Polymerization of siloxane is improved using a gypsum-based slurry that includes stucco, Class C fly ash, magnesium oxide and an emulsion of siloxane and water. This slurry is used in a method of making water-resistant gypsum articles that includes making an emulsion of siloxane and water, then combining the slurry with a dry mixture of stucco, magnesium oxide and Class C fly ash. The slurry is then shaped as desired and the stucco is allowed to set and the siloxane polymerizes.The resulting product is useful for making a water-resistant gypsum panel having a core that includes interwoven matrices of calcium sulfate dihydrate crystals and a silicone resin, where the interwoven matrices have dispersed throughout them a catalyst comprising magnesium oxide and components from a Class C fly ash.
摘要:
An improved gypsum slurry that includes water, calcium sulfate hemihydrate, a polycarboxylate dispersant and a modifier. The modifier is chemically configured to improve the efficacy of the polycarboxylate dispersant. Preferred modifiers include cement, lime, slaked lime, soda ash, carbonates, silicates and phosphates.
摘要:
A method for calcining gypsum in a pressurized reactor by injecting combustion gases and air into the pressurized reactor to create a fluidized bed of gypsum, and heating the fluidized bed of gypsum in the pressurized reactor sufficiently to form a calcined hemihydrate.
摘要:
A method for forming a gypsum slurry comprises the steps of combining gypsum and water to form a slurry, combining cellulose ether with at least a second material configured to delay solubilization of the cellulose ether, and adding the combined cellulose ether and at least a second material to the slurry.