Compositions and methods for water-resistant gypsum fiber products
AssigneeUnited States Gypsum Company
InventorsDavid R. Blackburn, Yufeng Xu
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Abstract
A water-resistant gypsum fiber product comprising siloxane and coated with a coating comprising alkali metal organosiliconate is provided. A method of making a gypsum fiber product in which siloxane is cross-linked at the surface of the product is also provided. A fuel-efficient method for making the product and reducing the amount of siloxane dust released is provided as well.
Claims10
A gypsum fiber product comprising a core and a coating, wherein the core comprises gypsum and siloxane and the coating comprises alkali metal organosiliconate, wherein the core is coated on at least one side with the coating, and wherein at least a portion of siloxane is crosslinked at the surface of the gypsum fiber product.
A method of making a water-resistant gypsum fiber product, the method comprising:
- preparing a gypsum slurry comprising calcium sulfate dihydrate;
- heating the slurry under pressure to calcine the calcium sulfate dihydrate to form alpha-calcined calcium sulfate hemihydrate;
- relieving the pressure;
- adding a siloxane dispersion to the slurry;
- dewatering the slurry to form a filter cake;
- forming the cake into a desired shape;
- allowing the cake to set to form a product;
- coating the product with a coating comprising alkali metal organosiliconate;
- and
- crosslinking siloxane at the surface of the product by drying the coated product in a kiln.
A method for decreasing the amount of siloxane dust generated in a kiln, the method comprising:
- preparing a gypsum slurry comprising calcium sulfate dihydrate;
- heating the slurry under pressure to calcine the calcium sulfate dihydrate to form alpha-calcined calcium sulfate hemihydrate;
- relieving the pressure;
- adding a siloxane dispersion to the slurry;
- dewatering the slurry to form a filter cake;
- forming the cake into a desired shape;
- allowing the cake to set to form a product;
- coating the product with a coating comprising alkali metal organosiliconate;
- and
- thereby decreasing the amount of siloxane dust generated in a kiln.
Dependencies are inferred from the claim text.