Gypsum boards having a titanate or zirconate coupling agent with glass fiber reinforcements

Abstract

A bond is created between gypsum crystals and between gypsum crystals and glass fiber reinforcement in a gypsum board during cure by incorporation of titanium or zirconium based coupling compositions incorporated in the gypsum slurry. The commercially available titanium or zirconium based coupling has a generic formula of the type [RO—}-nTi-[—OXR′Y]4-n or [RO—}-nZr-[—OXR′Y]4-n. These coupling compositions chemically bond to glass fibers by replacing the —OH groups present on the glass fibers in aqueous solutions with Ti—O or Zr—O bonds. The X functionality of the coupling composition is selected to be a phosphato or pyrophosphato group to form bond with calcium ions of the gypsum crystal. The bond created by the titanium or zirconium based coupling composition results in load transfer between gypsum crystals in the gypsum matrix and between the glass fibers and gypsum matrix, resulting in improved flexure strength and nail pullout resistance.

1 . A gypsum board, comprising: 
 a. a gypsum matrix formed from an aqueous gypsum slurry containing titanium or zirconium based coupling composition and having a bottom and a top, said gypsum matrix being operable to form gypsum crystals having calcium ions when said gypsum board is cured;    b. a first facer sheet placed on said bottom of said gypsum matrix;    c. a second facer sheet placed on said top of said gypsum matrix;    d. said gypsum slurry containing a coupling composition of the type [RO—}-nTi-[—OXR′Y]4-n] or [RO—}-nZr-[—OXR′Y]4-n], said coupling composition type being operable to form Ti—O or Zr—O bonds when bonding chemically to glass fibers and having X functionality, said X functionality being a phosphate or pyrophosphate group operable to bond to calcium ions of gypsum crystal;    e. said coupling composition bonding chemically to said glass fibers by replacing said OH ions with said Ti—O or Zr—O bonds, and forming a coupling composition coating on said external surfaces of said glass fibers,    f. said coupling composition bonding chemically to said calcium ions of said gypsum crystals during said gypsum board cure by forming a bond with said X functionality of said coupling composition, and said coupling composition coating providing increased strength, flexure resistance and nail pull out resistance to said gypsum board.    
   
   
       2 . A gypsum board as recited by  claim 1 , wherein said gypsum matrix contains one or more glass fibers, and said glass fibers having external surfaces with OH ions thereon.  
   
   
       3 . A gypsum board as recited by  claim 1 , wherein each of said first and said second facer sheets comprises Kraft paper.  
   
   
       4 . A gypsum board as recited by  claim 1 , wherein said gypsum matrix comprises calcium sulphate hemihydrate (CaSO 4 .1/2H 2 O), calcium sulphate anhydrite (CaSO 4 ), hydraulic setting cement and water.  
   
   
       5 . A gypsum board as recited by  claim 3 , wherein said hydraulic setting cement is selected from the group consisting of Portland cements, sulphate resisting cements, blast furnace cements, pozzolanic cements, and high alumina cements  
   
   
       6 . A gypsum board as recited by  claim 1 , wherein said coupling composition is added to said gypsum slurry in amounts ranging from 0.001 wt % to 0.8 wt % based on gypsum weight.  
   
   
       7 . A gypsum board as recited by  claim 1 , wherein said coupling composition is added to the gypsum slurry in amounts ranging from 0.1 wt % to 0.8 wt % based on gypsum weight.  
   
   
       8 . A gypsum board as recited by  claim 1 , wherein said coupling composition comprises LICA 12 Titanium IV 2,2 [bis 2-propenolatomethyl] butanolato, tris [dioctyl] phosphate-O.  
   
   
       9 . A gypsum board as recited by  claim 1 , wherein said coupling composition comprises LICA 38 Titanium IV 2,2 [bis 2-propenolatomethyl] butanolato, tris [dioctyl] pyrophosphato-O.  
   
   
       10 . A gypsum board as recited by  claim 1 , wherein said coupling composition comprises LICA 38 ENP Titanium IV 2,2 [bis 2-propenolatomethyl] butanolato, tris [dioctyl] pyrophosphato-O:Ethoxylated nonyl phenol-1:1.  
   
   
       11 . A gypsum board as recited by  claim 1 , wherein said coupling composition comprises LICA 38J Titanium IV [bis-2-propenolato-methyl]-1-butanolato, bis(dioctyl) pyrophosphato-O, {adduct} 3 moles N,N-dimethylamino-alkyl propenoamide.  
   
   
       12 . A gypsum board as recited by  claim 1 , wherein said coupling composition comprises NZ 38 Zirconium IV 2,2[bis-2-propenolato methyl]butanolato,tris(dioctyl)pyrophosphate-O.  
   
   
       13 . A gypsum board as recited by  claim 1 , wherein said coupling composition comprises NZ 38J Zirconium IV 2,2-dimethyl 1,3 propanediolato, bis [dioctyl]pyrophosphato-O [addduct]2 moles N,N-dimethylamino-alkyl propenoamide.  
   
   
       14 . A gypsum board as recited by  claim 2 , wherein said glass fibers are randomly arranged.  
   
   
       15 . A gypsum board as recited by  claim 2 , wherein said glass fibers are arranged in the form of organized structures such as mats.  
   
   
       16 . A process for manufacture of gypsum board, comprising the steps of: 
 a. dissolving a titanium or zirconium based coupling composition in an aqueous solution;    b. adding calcium sulphate hemihydrate with additives including starch, binder, accelerator, retarder, superplasticizer, water resistant agent, foaming agents, biocides etc to said aqueous solution form a aqueous gypsum slurry;    c. adding glass fibers to said aqueous gypsum slurry;    d. casting said aqueous gypsum slurry having said titanium or zirconium based coupling composition with said glass fibers on a first facer sheet, said gypsum casting having a top and a bottom;    e. applying a second facer sheet placed on said top of said gypsum casting and forming a gypsum board; and    f. drying and curing said gypsum board, said gypsum board being operative to increase strength, flexure resistance and nail pull out resistance.    
   
   
       17 . A process for manufacture of gypsum board, comprising the steps of: 
 a. dissolving a titanium or zirconium based coupling composition in an aqueous solution;    b. adding calcium sulphate hemihydrate with additives including starch, binder, accelerator, retarder, superplasticizer, water resistant agent, foaming agents, biocides etc to said aqueous solution form a aqueous gypsum slurry;    c. casting said aqueous gypsum slurry having said titanium or zirconium based coupling composition on a first facer sheet, said gypsum casting having a top and a bottom;    d. applying a second facer sheet placed on said top of said gypsum casting and forming a gypsum board; and    e. drying and curing said gypsum board, said gypsum board being operative to increase strength, flexure resistance and nail pull out resistance.