Lightweight wallboard compositions containing natural polymers
AssigneeNational Gypsum Properties, LLC
InventorsGopalakrishnan Sethuraman, Elisha Stav, Lambert J. Metz
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Abstract
Compositions useful for the preparation of lightweight, high strength wallboards, and methods of making same are disclosed. The composition includes a slurry of calcium sulfate hemihydrate (stucco), water, starch, and a foam. The foam acts to provide large bubbles within the core slurry, thereby lightening the weight of the wallboard. The composition and method provide wallboards having lighter weights compared to standard wallboard, increased core strength, and increased paper-to-core bonding.
Claims43
A lightweight wallboard core slurry composition comprising:
- calcium sulfate hemihydrate;
- starch;
- foam;
- and
- water, wherein:
- the starch is present at about 1.5 weight percent to about 3.0 weight percent, based on the amount of calcium sulfate hemihydrate;
- the water-to-stucco weight ratio is about 0.7 to about 0.95;
- and
- the slurry contains air bubbles.
A lightweight construction grade wallboard comprising:
- a core comprising calcium sulfate hemihydrate, starch, foam, and water;
- a first cover sheet;
- and
- a second cover sheet, wherein:
- the starch is present at about 1.5 weight percent to about 3.0 weight percent based on the weight of calcium sulfate hemihydrate;
- the core is surfaced on the top and bottom by the first sheet and the second sheet;
- and
- the wallboard has a density of about 1450 pounds per thousand square feet for a half inch thick board to about 1560 pounds per thousand square feet for a half inch thick board.
A gypsum wallboard panel comprising:
- a first paper coversheet;
- a second paper coversheet;
- and
- a core disposed between the first coversheet and the second coversheet, wherein:
- the core comprises calcium sulfate hemihydrate, starch, and air bubbles;
- the starch is present in an amount of about 2.1 weight percent of the amount of calcium sulfate hemihydrate;
- the average diameter of the air bubbles is about 300μ to about 500μ;
- and
- the core has a density of about 1450 pounds per thousand square feet for a half inch thick board to about 1560 pounds per thousand square feet for a half inch thick board.
A method of preparing lightweight wallboard, the method comprising:
- forming a slurry comprising water, calcium sulfate hemihydrate, starch, and foam to form a slurry containing air bubbles, wherein the slurry comprises at least about 30 weight percent calcium sulfate hemihydrate and the starch is present at about 1.5 weight percent to about 3.0 weight percent based on the amount of calcium sulfate hemihydrate;
- depositing the slurry on a first sheet of face paper;
- applying a second sheet of face paper on the slurry to form a wallboard having a lightweight core;
- and
- drying the wallboard;
- wherein the dried wallboard has a density of about 1450 pounds per thousand square feet for a half inch thick board to about 1560 pounds per thousand square feet for a half inch thick board.
Dependencies are inferred from the claim text.