Method of water dispersing pregelatinized starch in making gypsum products
AssigneeUnited States Gypsum Company
InventorsQiang Yu, Weixin David Song
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Abstract
The invention provides in one embodiment a gypsum-containing slurry including stucco and an aqueous pre-dispersion of a pregelatinized starch. Also provided is a method of making gypsum wallboard by providing a pre-dispersion of the pregelatinized starch in water, and adding the pregelatinized starch pre-dispersion to the gypsum-containing slurry. The pregelatinized starch can have a particle size distribution within the following range: d (0.1)=about 20μ-35μ, d (0.5)=about 60μ-110μ, d (0.9)=about 100μ-220μ.
Claims14
A method of making gypsum board, comprising:
- (a) providing pregelatinized starch having a particle size distribution within the following ranges:
- d(0.1)=from about 20μ to about 35μ,
- d(0.5)=from about 60μ to about 110μ,
- d(0.9)=from about 100μ to about 220μ;
- (b) dispersing the pregelatinized starch in water to form a pregelatinized starch dispersion;
- (c) introducing stucco to a mixer having nozzles that deliver water into the mixer and injecting the pregelatinized starch dispersion into the mixer adjacent the nozzles to fully disperse the starch in the resulting slurry;
- (d) disposing the slurry containing the dispersed starch between a first cover sheet and a second cover sheet to form a panel;
- (e) cutting the panel into a board of predetermined dimensions;
- and
- (f) drying the board.
A method of making gypsum board, comprising:
- (a) providing pregelatinized starch having a particle size distribution of d (0.1)=about 20μ, d (0.5)=about 60μ, d (0.9)=about 100μ;
- (b) dispersing the pregelatinized starch in water to form a pregelatinized starch dispersion;
- (c) introducing stucco to a mixer having nozzles that deliver water into the mixer, and injecting the pregelatinized starch dispersion into the mixer adjacent the nozzles to disperse the starch in the resulting slurry during a contact time with the stucco and water of less than one second;
- (d) disposing the slurry containing the dispersed starch between a first cover sheet and a second cover sheet to form a panel;
- (e) cutting the panel into a board of predetermined dimensions;
- and
- (f) drying the board.
A method of making gypsum board, comprising:
- (a) providing ground pregelatinized starch having a particle size distribution within the following ranges:
- d(0.1)=from about 20μ to about 35μ,
- d(0.5)=from about 60μ to about 110μ,
- d(0.9)=from about 100μ to about 220μ;
- (b) dispersing the ground pregelatinized starch in water to form a ground pregelatinized starch dispersion;
- (c) introducing stucco to a mixer having nozzles that deliver water into the mixer and injecting the ground pregelatinized starch dispersion into the mixer adjacent the nozzles to disperse the starch in the resulting slurry;
- (d) disposing the slurry containing the dispersed starch between a first cover sheet and a second cover sheet to form a panel;
- (e) cutting the panel into a board of predetermined dimensions;
- and
- (f) drying the board.
Dependencies are inferred from the claim text.