Gypsum-containing product

Patent metadata

Field	Value
Publication number	US-8974597-B2
Application number	US-201313934028-A
Country	US
Kind code	B2
Filing date	Jul 2, 2013
Priority date	Aug 21, 1997
Publication date	Mar 10, 2015
Grant date	Mar 10, 2015

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.

First claim

What is claimed is:

1. A set gypsum-containing product having been prepared by a method comprising:
inserting into a joint between edges of gypsum boards a mixture comprising (a) at least one of (i) binder or (ii) thickener, (b) calcium sulfate material, (c) water, and (d) one or more enhancing materials selected from the group consisting of: 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, and
maintaining the mixture under conditions sufficient for the calcium sulfate material to form a set gypsum material,
the enhancing material or materials having been included in the mixture in an amount such that the set gypsum formed has greater resistance to permanent deformation than it would have if the enhancing material had not been included in the mixture.

2. The set gypsum-containing product of claim 1 , wherein the mixture comprises binder and thickener.

3. The set gypsum-containing product of claim 1 , wherein the mixture further comprises non-leveling agent.

4. The set gypsum-containing product of claim 2 , wherein the mixture further comprises non-leveling agent.

5. The set gypsum-containing product of claim 1 , wherein the calcium sulfate material is calcined gypsum and the amount of enhancing material is from about 0.004 to about 2.0 percent by weight, based on the weight of the calcined gypsum.

6. The set gypsum-containing product of claim 5 , wherein the enhancing material comprises sodium trimetaphosphate.

7. The set gypsum-containing product of claim 1 , wherein the mixture comprises binder comprising latex.

8. The set gypsum-containing product of claim 7 , wherein the binder is poly(vinyl acetate), or poly(ethylene-co-vinyl acetate).

9. The set gypsum-containing product of claim 7 , wherein the binder is included in a range of from about 1 to about 15 percent by weight of the composition.

10. The set gypsum-containing product of claim 8 , wherein the binder is included in a range of from about 1 to about 15 percent by weight of the composition.

11. The set gypsum-containing product of claim 1 , wherein the mixture comprises a cellulosic thickener.

12. The set gypsum-containing product of claim 11 , wherein the cellulosic thickener is ethylhydroxy ethylcellulose, hydroxypropyl methylcellulose, methylhydroxypropyl cellulose, or hydroxyethyl cellulose.

13. The set gypsum-containing product of claim 11 , wherein the thickener is included in a range of from about 0.1 to about 2 percent by weight of the composition.

14. The set gypsum-containing product of claim 12 , wherein the thickener is included in a range of from about 0.1 to about 2 percent by weight of the composition.

15. The set gypsum-containing product of claim 3 , wherein the non-leveling agent is attapulgite clay, sepiolite clay, bentonite clay, or montmorillonite clay.

16. The set gypsum-containing product of claim 3 , wherein the non-leveling agent is included in a range of from about 1 to about 10 percent by weight of the composition.

17. The set gypsum-containing product of claim 15 , wherein the non-leveling agent is included in a range of from about 1 to about 10 percent by weight of the composition.

18. The set gypsum-containing product of claim 4 , wherein the non-leveling agent is attapulgite clay, sepiolite clay, bentonite clay, or montmorillonite clay.

19. The set gypsum-containing product of claim 4 , wherein the non-leveling agent is included in a range of from about 1 to about 10 percent by weight of the composition.

20. The set gypsum-containing product of claim 18 , wherein the non-leveling agent is included in a range of from about 1 to about 10 percent by weight of the composition.

Assignees

• United States Gypsum Co

Inventors

• Yu Qiang
• Sucech Steven W
• Groza Brent E
• Mlinac Raymond J
• Jones Frederick T
• Henkels Paul J

Classifications

• C04B16/04

  Macromolecular compounds (C04B16/02 takes precedence) · CPC title

• C04B16/02 Primary

  Cellulosic materials (cellulosic waste materials, e.g. sawdust, rice husks, C04B18/24) · CPC title

• Y10T428/192

  Sheets or webs coplanar · CPC title

• C04B2111/00672

  Pointing or jointing materials · CPC title

• Y10T428/31971

  Of carbohydrate · CPC title