US 11,787,739 B2
Flour binder for gypsum board, and related methods, product, and slurries
Yijun Sang, Oak Park, IL (US); and Mark Hemphill, Hawthorn Woods, IL (US)
Assigned to United States Gypsum Company, Chicago, IL (US)
Filed by United States Gypsum Company, Chicago, IL (US)
Filed on Sep. 18, 2020, as Appl. No. 17/25,003.
Claims priority of provisional application 62/939,173, filed on Nov. 22, 2019.
Prior Publication US 2021/0155543 A1, May 27, 2021
Int. Cl. C04B 24/38 (2006.01); C04B 28/14 (2006.01); B32B 13/04 (2006.01); B32B 13/08 (2006.01); E04C 2/04 (2006.01); B32B 37/00 (2006.01); C09J 103/02 (2006.01); B32B 37/15 (2006.01); B32B 38/00 (2006.01); C04B 111/00 (2006.01); B32B 38/16 (2006.01)
CPC C04B 24/383 (2013.01) [B32B 13/04 (2013.01); B32B 13/08 (2013.01); B32B 37/0038 (2013.01); B32B 37/15 (2013.01); B32B 38/0036 (2013.01); B32B 38/164 (2013.01); C04B 28/14 (2013.01); C09J 103/02 (2013.01); E04C 2/043 (2013.01); E04C 2/049 (2013.01); B32B 38/0004 (2013.01); B32B 2038/166 (2013.01); B32B 2309/02 (2013.01); B32B 2315/18 (2013.01); B32B 2317/20 (2013.01); C04B 2111/0062 (2013.01); C04B 2201/50 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of making gypsum board comprising:
(a) forming an acid-modified flour by (i) combining starting flour from a dry milling process and a strong acid that substantially avoids chelating calcium ions to form a mixture, (ii) heating the mixture at a temperature of from about 50° C. to about 100° C., (iii) adding a neutralizer to the mixture to achieve a pH of from about 4.0 to about 7.5, and (iv) drying the mixture, the acid-modified flour having a hot water viscosity of from about 50 BU to about 420 BU, as measured according to the HWVA test;
(b) adding the acid-modified flour to at least water and stucco to form a slurry;
(c) disposing the slurry to form a gypsum board core between a first cover sheet and a second cover sheet to form a wet assembly;
(d) cutting the wet assembly into the gypsum board; and
(e) drying the gypsum board.