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 |
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.
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