Gypsum panels, systems, and methods

Abstract

Gypsum panels and methods of making the same are provided. A method of making a gypsum panel includes forming a first gypsum slurry by combining stucco, water, a siliconate, and a phosphate salt or polymer, and setting the first gypsum slurry to form at least part of a core of the gypsum panel, wherein the gypsum panel displays a 2-hour water absorption test weight increase of at least 10 weight percent less than an otherwise identical comparative panel containing no phosphate salt or polymer in its core.

We claim: 
     
         1 . A method of making a gypsum panel, comprising:
 forming a first gypsum slurry by combining stucco, water, a siliconate, siloxane, and at least one of a phosphate salt or a polymer; and   setting the first gypsum slurry to form at least part of a core of the gypsum panel,   wherein:
 the siliconate is present in the first gypsum slurry in an amount of 25 lb/msf to 50 lb/msf, and 
 a ratio of the siloxane to the siliconate in the first gypsum slurry is from 1:10 to 1:30. 
   
     
     
         2 . The method of  claim 1 , wherein the phosphate salt or polymer comprises sodium trimetaphosphate (STMP), sodium hexametaphosphate (SHMP), ammonium polyphosphate (APP), polyvinyl alcohol (PVA), a hydrophobic latex, or a dispersible polymer powder comprising a styrene/maleic acid copolymer, a styrene-butadiene copolymer, a styrene-acrylate, an acrylate, or a terpolymer of ethylene, vinyl chloride and vinyl laurate. 
     
     
         3 . The method of  claim 1 , wherein the siliconate is present in the first gypsum slurry in an amount of 25 lb/msf to 40 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         4 . The method of  claim 1 , wherein the siliconate is present in the first gypsum slurry in an amount of from 25 lb/msf to 30 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         5 . The method of  claim 1 , wherein a ratio of siloxane to siliconate in the first gypsum slurry is from 1:15 to 1:20. 
     
     
         6 . The method of  claim 1 , wherein a ratio of siloxane to siliconate in the first gypsum slurry is 1:15. 
     
     
         7 . The method of  claim 1 , wherein the siloxane is present in the first gypsum slurry in an amount of from 1 lb/msf to 5 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         8 . The method of  claim 1 , wherein the siloxane is present in the first gypsum slurry in an amount of from 2 lb/msf to 5 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         9 . The method of  claim 1 , wherein the gypsum panel displays a 2-hour water absorption test weight increase of at least 10 weight percent less than an otherwise identical comparative panel containing no phosphate salt or polymer in its core, 
     
     
         10 . The method of  claim 1 , wherein the siliconate comprises sodium or potassium methylsiliconate, sodium or potassium ethyl siliconate, propylsiliconate, isopropylsiliconate, butylsiliconate, octylsiliconate, phenylsiliconate, or any combination thereof. 
     
     
         11 . The method of  claim 1 , wherein the siloxane comprises polymethylhydrogensiloxane. 
     
     
         12 . The method of  claim 1 , wherein the phosphate salt or polymer is present in the first gypsum slurry in an amount of 0.5 lb/msf to 50 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         13 . The method of  claim 1 , wherein the phosphate salt or polymer is present in the first gypsum slurry in an amount of from 10 lb/msf to 30 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         14 . The method of  claim 1 , wherein the phosphate salt or polymer comprises PVA that is present in the first gypsum slurry in an amount of from 10 lb/msf to 30 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         15 . The method of  claim 1 , wherein the phosphate salt or polymer comprises STMP, SHMP, or APP, that is present in the first gypsum slurry in an amount of from 0.5 lb/msf to 10 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         16 . The method of  claim 1 , wherein the phosphate salt or polymer comprises a hydrophobic latex that is present in the first gypsum slurry in an amount of from 3 lb/msf to 10 lb/msf, and a thickness of the gypsum panel is ¼ inch to ¾ inch. 
     
     
         17 . The method of  claim 1 , wherein the gypsum panel displays at least one of:
 an average water absorption of not more than 15 percent by weight, after 2 hours of immersion, according to ASTM C1396/C1396M-14a (2014),   an average water absorption of not more than 15 percent by weight, after 2 hours of immersion, according to ASTM C1177/C117M-13 (2013), or   an average water absorption of not more than 5 percent by weight, after 2 hours of immersion, according to ASTM C1178/C1188M-13 (2013).   
     
     
         18 . The method of  claim 1 , further comprising depositing the first gypsum slurry onto a first surface of a facer material. 
     
     
         19 . The method of  claim 18 , wherein the facer material comprises a fiberglass mat or a paper facer. 
     
     
         20 . A gypsum panel made by the method of  claim 1 .