Gypsum-containing product and method for producing same

• US 7,964,034 B2
• Filed: 06/09/2010
• Issued: 06/21/2011
• 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: Groza, Brent E., Henkels, Paul J., Jones, Frederick T., Sucech, Steven W., Mlinac, Raymond J., Yu, Qiang
• Primary Examiner(s): Marcantoni; Paul
• Application Number:
  US12/797,013
• Publication Number:
  US 20100273020A1
• Time in Patent Office: 377 Days
• Field of Search: 106/772, 428/332, 428/703, 428/704, 156/39
• US Class Current: 106/772
• 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 method for producing a set gypsum-containing product comprising forming a mixture of calcined gypsum, water, an accelerator, and one or more enhancing materials chosen from the group consisting of:

sodium trimetaphosphate, tetrapotassium pyrophosphate, tetrasodium pyrophosphate, aluminum trimetaphosphate, sodium acid pyrophosphate, ammonium polyphosphate having 1000-3000 repeating phosphate units, and acids, salts, or the anionic portions thereof, and

maintaining the mixture under conditions sufficient for the calcined gypsum to form an interlocking matrix of set gypsum,

the enhancing material or materials having been included in the mixture in an amount such that the set gypsum-containing product has greater resistance to permanent deformation than it would have if the enhancing material had not been included in the mixture, such that when the mixture is cast in the form of ½

inch gypsum board, said 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,

the accelerator having been included in an amount such that the set gypsum-containing product has greater strength than it would have if the accelerator had not been included in the mixture.

2. The method of claim 1, wherein the concentration of the enhancing material in the mixture is from 0.004 to 2.0 percent by weight, based on the weight of the calcined gypsum.

3. The method of claim 1, wherein the mixture further comprises a pregelatinized starch.

4. The method of claim 1, wherein the calcined gypsum comprises one or more of:

calcium sulfate anhydrite;

calcium sulfate hemihydrate;

or ions of calcium and sulfate.

5. The method of claim 1, wherein the enhancing material comprises one or more of the following salts, or the anionic portions thereof:

sodium trimetaphosphate and ammonium polyphosphate having 1000-3000 repeating phosphate units.

6. The method of claim 1, wherein the mixture comprises 0.02-1.5 weight percent (based on the weight of calcined gypsum in the mixture) of chloride ions or salts thereof.

7. A method for producing a set gypsum-containing product comprising:

forming a mixture of a calcined gypsum water, and one or more enhancing materials chosen from the group consisting of;

sodium trimetaphosphate, tetrapotassium pyrophosphate, tetrasodium pyrophosphate, aluminum trimetaphosphate, sodium acid pyrophosphate, ammonium polyphosphate having 1000-3000 repeating phosphate units, and acids, salts, or the anionic portions thereof, and

maintaining the mixture under conditions sufficient for the calcined gypsum 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, such that when the mixture is cast in the form of ½

inch gypsum board, said 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.

8. The method of claim 7, wherein the set gypsum material comprises an interlocking matrix of set gypsum.

9. The method of claim 7, wherein said mixture includes an accelerator.