Gypsum-containing board and tile, and method for producing same

• US 7,758,980 B2
• Filed: 08/12/2008
• Issued: 07/20/2010
• Est. Priority Date: 08/21/1997
• Status: Expired due to Fees

• Current Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Original Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Inventors: Yu, Qiang, Groza, Brent E., Henkels, Paul J., Jones, Frederick T., Sucech, Steven W., Mlinac, Raymond J.
• Primary Examiner(s): MARCANTONI, PAUL D
• Application Number:
  US12/190,203
• Publication Number:
  US 20090047545A1
• Time in Patent Office: 707 Days
• Field of Search: 428/703, 428/704.332, 428/704, 428/332, 428/772
• US Class Current: 428/703
• CPC Class Codes: C04B 14/00 Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone expanding or defibrillating materials C04B20/00
• CPC Class Codes: C04B 14/185 expanded
• CPC Class Codes: C04B 14/38 Fibrous materials; Whiskers
• CPC Class Codes: C04B 14/46 Rock wool ; Ceramic or silicate fibres C04B14/40, C04B14/42 take precedence
• CPC Class Codes: C04B 16/02 Cellulosic materials cellulosic waste materials, e.g. sawdust, rice husks, C04B18/24
• CPC Class Codes: C04B 16/04 Macromolecular compounds C04B16/02 takes precedence
• CPC Class Codes: C04B 20/0048 Fibrous materials
• CPC Class Codes: C04B 2103/44 Thickening, gelling or viscosity increasing agents
• CPC Class Codes: C04B 2111/00094 Sag-resistant materials
• CPC Class Codes: C04B 2111/00612 as one or more layers of a layered structure
• CPC Class Codes: C04B 2111/0062 Gypsum-paper board like materials
• CPC Class Codes: C04B 2111/00672 Pointing or jointing materials
• CPC Class Codes: C04B 2111/52 Sound-insulating materials
• CPC Class Codes: C04B 2111/54 Substitutes for natural stone, artistic materials or the like
• CPC Class Codes: C04B 22/004 containing dissolved additives or active agents, i.e. aqueous solutions used as gauging water C04B22/0026 takes precedence
• CPC Class Codes: C04B 22/16 containing phosphorus in the anion, e.g. phosphates
• CPC Class Codes: C04B 24/16 Sulfur-containing compounds
• CPC Class Codes: C04B 24/26 obtained by reactions only involving carbon-to-carbon unsaturated bonds C04B24/243 takes precedence
• CPC Class Codes: C04B 24/32 Polyethers, e.g. alkylphenol polyglycolether
• CPC Class Codes: C04B 24/38 Polysaccharides or derivatives thereof C04B24/243 takes precedence
• CPC Class Codes: C04B 24/383 : Cellulose or derivatives thereof
• CPC Class Codes: C04B 28/14 : containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: C04B 28/147 : beta-hemihydrate
• CPC Class Codes: C04B 38/10 : by using foaming agents C04B38/02 takes precedenceor by using mechanical means, e.g. adding preformed foam
• CPC Class Codes: C04B 40/0028 : Aspects relating to the mixing step of the mortar preparation
• CPC Class Codes: C04B 41/009 : characterised by the material treated
• CPC Class Codes: C04B 41/70 : for obtaining at least two superposed coatings having different compositions
• CPC Class Codes: Y10T 428/192 : Sheets or webs coplanar
• CPC Class Codes: Y10T 428/26 : Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/31971 : Of carbohydrate

Abstract

The invention provides a set gypsum-containing product having increased resistance to permanent deformation and a method for preparing it comprising forming a mixture of a calcium sulfate material, water, and an appropriate amount of one or more enhancing materials chosen from condensed phosphoric acids, each of which comprises 2 or more phosphoric acid units; and salts or ions of condensed phosphates, each of which comprises 2 or more phosphate units. The mixture is then maintained under conditions sufficient for the calcium sulfate material to form a set gypsum material.

Claims

1. A gypsum board comprising set gypsum formed from at least calcined gypsum, water and sodium trimetaphosphate, wherein the amount of the sodium trimetaphosphate compound is from about 0.004 to about 2.0% by weight of the calcined gypsum.

2. The gypsum board of claim 1, wherein the amount of the sodium trimetaphosphate compound is from about 0.04 to about 0.16% by weight of the calcined gypsum.

3. The gypsum board of claim 1, wherein the board has a shrinkage of less than about 0.13% across its width and less than about 0.26% across its length, as determined according to ASTM C473-95.

4. The gypsum board of claim 1, wherein the gypsum board has a sag resistance, as determined according to ASTM C473-95, of less than about 0.1 inch per two foot length of said board.

5. The gypsum board of claim 1, wherein the board further comprises a pregelatinized starch.

6. The gypsum board of claim 1, wherein the set gypsum is further formed from at least one aqueous foaming agent.

7. The gypsum board of claim 1, wherein the set gypsum is in the form of a core material sandwiched between cover sheets.