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US 5,922,447 AGranted
Lightweight gypsum board
AssigneeUnited States Gypsum Company
InventorMirza A. Baig
Life of this patent
Estimating the term…
Abstract
A lightweight gypsum board is provided, including, by dry weight, gypsum as the largest single ingredient, perlite as the second largest single ingredient, and starch as a minor ingredient, in the board. The starch may be pre-cooked prior to mixing, and is dispersed in the core of the board to act as a binder for binding the gypsum to the perlite. Gypsum board made according to the invention is lighter in weight, yet has a comparable nail pull value to conventional wallboard.
Claims14
A lightweight gypsum wallboard comprising:
- a core including:
- a. gypsum, said gypsum being the largest single ingredient, by dry weight in the core, said gypsum comprising at least 50% of the dry weight of the core;
- b. perlite having a bulk density of approximately 3-3.5 pounds per cubic foot, said perlite being the second largest single ingredient, by dry weight, in the core, said perlite comprising less than 50% of the dry weight of the core and being distributed throughout said core;
- c. fibers comprising in the range of 0.5% to 5.6% of the dry weight of the core;
- d. starch comprising in the range of 0.25% to 6% of the dry weight of the core:
- and
- e. first and second sheets of face paper, said core being surfaced by said first and second sheets;
- wherein the wallboard ha a density of between 21.5 and 37.1 pounds per cubic foot.
5 more elements
A process of making lightweight gypsum board having a core comprising:
- a. providing a supply of calcined gypsum, said gypsum being the largest single ingredient by dry weight in the core, said gypsum comprising at least 50% of the dry weight of the core;
- b. providing a supply of perlite having a bulk density of approximately 3-3.5 pounds per cubic foot and a supply of fibers in the range of 0.5% to 5.6% of the dry weight of the core, said perlite being the second largest ingredient by dry weight in the core, said perlite comprising less than 50% of the dry weight of the core;
- c. providing a supply of starch comprising in the range of 0.25% to 6% of the dry weight of the core;
- d. mixing said gypsum, said perlite, said fibers and said starch together with water to form a homogeneous slurry;
- e. spreading said slurry upon a first sheet of face paper;
- f. applying a second sheet of face paper upon said slurry to form a board having a core;
- and
- g. drying the board;
- wherein the board has a density of between 21.5 and 37.1 pounds per cubic foot.
6 more elements
Dependencies are inferred from the claim text.