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US 9,540,810 B2Granted
Pregelatinized starch with mid-range viscosity, and product, slurry and methods related thereto
AssigneeUnited States Gypsum Company
InventorsYijun Sang, Chris C. Lee, Cesar Chan, Weixin David Song
Life of this patent
Estimating the term…
Abstract
Disclosed are product (e.g., panels), slurry, and methods relating to a pregelatinized starch having a mid-range viscosity (i.e., from about 20 centipoise to about 700 centipoise), and an extruded pregelatinized starch.
Claims20
A board comprising:
- a set gypsum core disposed between two cover sheets, the core formed from a slurry comprising stucco, water, and at least one extruded pregelatinized starch, wherein the extruded pregelatinized starch is formed by modifying and extruding a wet starch having a water content less than about 25% wherein the modifying at least partially hydrolyzes the starch via acid and/or enzyme modification;
- the extruded pregelatinized starch having a cold water solubility greater than about 30% when measured at 25° C. and a cold water viscosity of a 10 wt. % slurry of the starch in water when measured at 25° C. and at a shear rate of 100 s−1 for 1 min is from about 120 centipoise to about 300 centipoise;
- the extruded pregelatinized starch causing the set gypsum core to have a compressive strength greater than an equivalent set gypsum core made with a starch having a cold water solubility less than about 30% instead of the extruded pregelatinized starch;
- the board having a core hardness of at least about 11 lbs, as determined according to ASTM C473-10.
1 more element
A method of making a board comprising:
- (a) mixing at least water, stucco, and at least one extruded pregelatinized starch to form a slurry, wherein the extruded pregelatinized starch is formed by modifying and extruding a wet starch having a water content less than about 25% wherein the modifying at least partially hydrolyzes the starch via acid and/or enzyme modification,
- (b) disposing the slurry between a first cover sheet and a second cover sheet to form a wet assembly,
- (c) cutting the wet assembly into a board, and
- (d) drying the board to form a set gypsum core between the first and second cover sheets;
- the extruded pregelatinized starch having a cold water solubility greater than about 30% when measured at 25° C. and a cold water viscosity of a 10 wt. % slurry of the starch in water when measured at 25° C. and at a shear rate of 100 s−1 for 1 min is from about 120 centipoinse to about 300 centipoise;
- the extruded pregelatinized starch causing the set gypsum core to have a compressive strength greater than an equivalent set gypsum core made with a starch having a cold water solubility less than about 30% instead of the extruded pregelatinized starch;
- the board having a core hardness of at least about 11 lbs, as determined according to ASTM C473-10.
4 more elements
Dependencies are inferred from the claim text.