Pregelatinized starch with mid-range viscosity, and product, slurry and methods related thereto

Patent metadata

Field	Value
Publication number	US-10464847-B2
Application number	US-201615359196-A
Country	US
Kind code	B2
Filing date	Nov 22, 2016
Priority date	Oct 23, 2012
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

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.

First claim

The invention claimed is:

1. 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, the slurry having a water/stucco ratio of from about 0.4 to about 1.1,
(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;
the extruded pregelatinized starch having (i) a cold water solubility greater than about 30% when measured at 25° C., and (ii) 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 of from about 120 centipoise to about 300 centipoise.

2. The method according to claim 1 , wherein the extruded pregelatinized starch has a cold water solubility of from about 30% to about 75%.

3. The method according to claim 2 , wherein the extruded pregelatinized starch has a cold water solubility of from about 50% to about 75%.

4. The method according to claim 2 , wherein the extruded pregelatinized starch has a particle size of from about 100 microns to about 400 microns.

5. The method according to claim 4 , wherein the extruded pregelatinized starch is in an amount of from about 0.1% to about 5% by weight based on the weight of stucco.

6. The method according to claim 5 , wherein the slurry has a water/stucco ratio of from about 0.45 to about 0.85.

7. The method according to claim 1 , wherein the extruded pregelatinized starch has a particle size of from about 100 microns to about 400 microns.

8. The method according to claim 7 , wherein the extruded pregelatinized starch is in an amount of from about 0.1% to about 5% by weight based on the weight of stucco.

9. The method according to claim 8 , wherein the slurry has a water/stucco ratio of from about 0.4 to about 0.9.

10. The method according to claim 1 , wherein the extruded pregelatinized starch is in an amount of from about 0.1% to about 5% by weight based on the weight of stucco.

11. The method according to claim 1 , wherein the board has a density of from about 20 pcf to about 35 pcf.

12. The method according to claim 1 , wherein the board has a density of from about 20 pcf to about 30 pcf.

13. The method according to claim 1 , wherein the slurry has a water/stucco ratio of from about 0.4 to about 0.9.

14. The method of claim 1 , wherein the slurry forms a set gypsum layer between the first and second cover sheets, and wherein the set gypsum layer has a compressive strength greater than an equivalent set gypsum layer made with a starch having a cold water solubility less than about 30%, and/or a cold water viscosity of less than about 120 centipoise or greater than about 300 centipoise, instead of the extruded pregelatinized starch.

15. The method of claim 14 , wherein the set gypsum layer has a compressive strength of at least about 1650 psi.

16. The method according to claim 1 , wherein:
the board has a density of from about 20 pcf to about 30 pcf;
the extruded pregelatinized starch is in an amount of from about 0.1% to about 5% by weight based on the weight of stucco; and
the slurry has a water/stucco ratio of from about 0.4 to about 0.9.

17. The method according to claim 16 , wherein the extruded pregelatinized starch has a cold water solubility of from about 50% to about 75%.

18. The method according to claim 16 , wherein the extruded pregelatinized starch has a particle size of from about 100 microns to about 400 microns.

19. The method according to claim 16 , wherein the extruded pregelatinized starch is in an amount of from about 0.1% to about 3% by weight based on the weight of stucco.

20. The method of claim 16 , wherein the slurry forms a set gypsum layer between the first and second cover sheets, and wherein the set gypsum layer has a compressive strength of at least about 1650 psi.

Assignees

• United States Gypsum Co

Inventors

• Sang Yijun
• Lee Chris C
• Chan Cesar
• Song Weixin David

Classifications

• C04B2111/00672

  Pointing or jointing materials · CPC title

• C04B2111/0062

  Gypsum-paper board like materials · CPC title

• C04B24/38

  Polysaccharides or derivatives thereof {(C04B24/243 takes precedence)} · CPC title

• C08B30/14

  Cold water dispersible or pregelatinised starch · CPC title

• C08L3/08

  Ethers · CPC title