Gypsum-containing product having increased resistance to permanent deformation and method and composition for producing it

• US 6,342,284 B1
• Filed: 08/21/1998
• Issued: 01/29/2002
• Est. Priority Date: 08/21/1997
• Status: Expired due to Term

• 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): Jones, Deborah
• Assistant Examiner(s): YOUNG, BRYANT L
• Application Number:
  US09/138,355
• Time in Patent Office: 1,257 Days
• Field of Search: 428/70, 156/39, 156/42, 156/43, 156/44, 106/772, 106/785, 106/819, 923/314
• US Class Current: 428/70
• CPC Class Codes: C04B 14/10 Clay sepiolite C04B14/042; grog C04B18/025
• CPC Class Codes: C04B 14/104 Bentonite, e.g. montmorillonite
• 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 18/24 Vegetable refuse, e.g. rice husks, maize-ear refuse; Cellulosic materials, e.g. paper , cork
• CPC Class Codes: C04B 20/0048 Fibrous materials
• CPC Class Codes: C04B 2103/0057 added as redispersable powders
• CPC Class Codes: C04B 2103/12 Set accelerators
• CPC Class Codes: C04B 2103/22 Set retarders
• CPC Class Codes: C04B 2103/408 Dispersants
• CPC Class Codes: C04B 2103/42 Pore formers
• 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 2111/34 Non-shrinking or non-cracking materials
• CPC Class Codes: C04B 2111/52 Sound-insulating materials
• 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 22/165 : Acids
• 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 24/2611 : Polyalkenes
• CPC Class Codes: C04B 24/28 : obtained otherwise than 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 41/52 : Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
• CPC Class Codes: C04B 41/70 : for obtaining at least two superposed coatings having different compositions
• CPC Class Codes: E04C 2/04 : of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibresE04C2/26 takes precedence; material or manufacture B28, C04
• CPC Class Codes: E04C 2/043 : of plaster E04C2/049 takes precedence
• CPC Class Codes: Y02W 30/91 : Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y10T 428/232 : Encased layer derived from inorganic settable ingredient

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 composition comprising a mixture of:

a calcium sulfate material, water, a pregelatinized starch and 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, wherein when said composition 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.

2. A composition comprising a mixture of:

a calcium sulfate material, water, an aqueous foam, and 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, wherein when said composition 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.

3. The composition of claim 2, wherein the mixture further comprises a pregelatinized starch.

4. A composition comprising set gypsum and host particles, at least a portion of the set gypsum being positioned in and about accessible voids in the host particles, wherein the composition comprises a mixture of:

the host particles having the accessible voids therein;

calcium sulfate hemihydrate, at least a portion of which is in the form of crystals in and about the voids of the host particles; and

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, wherein when said composition 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.

5. Gypsum board comprising set gypsum and at least one trimetaphosphate compound, said gypsum board having a sag resistance, as determined according to ASTM C473-95, of less than about 0.1 inch per two foot length of said board.

6. The gypsum board of claim 5, wherein said set gypsum and trimetaphosphate compound are in the form of a core material sandwiched between cover sheets.

7. The gypsum board of claim 6, wherein the cover sheets comprise paper.

8. The gypsum board of claim 5, said gypsum board having a shrinkage of less than about 0.06 inch per four foot width and less than about 0.30 inch per twelve foot length, as determined according to ASTM C473-95.

9. The gypsum board of claim 5, said gypsum board having 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.

18. The gypsum board of claim 5, wherein said gypsum board further comprises a pregelatinized starch.

19. The gypsum board of claim 18 wherein the amount of pregelatinized starch is from about 0.08 to about 0.5 percent by weight of the gypsum.

20. The gypsum board of claim 19, wherein the amount of pregelatinized starch is from about 0.16 to about 0.4 percent by weight of the gypsum.

21. The gypsum board of claim 19, wherein the amount of pregelatinized starch is about 0.3 percent by weight of the gypsum.

26. The gypsum board of claim 5, wherein said set gypsum has voids uniformly distributed therein.

27. The gypsum board of claim 26, wherein said set gypsum is further formed from at least one foaming agent, having the formula:

32. The gypsum board of claim 26, wherein the set gypsum is further comprises a pregelatinized starch and at least one foaming agent.

10. Gypsum board comprising set gypsum formed from at least calcined gypsum, water and at least one timetaphosphate compound, said gypsum board having a sag resistance, as determined according to ASTM C473-95, of less than about 0.1 inch per two foot length of said board.

11. The gypsum board of claim 10, wherein the amount of said trimetaphosphate compound is from about 0.004 to about 2.0% by weight of said calcined gypsum.

12. The gypsum board of claim 10, wherein said set gypsum is in the form of a core material sandwiched between cover sheets.

13. The gypsum board of claim 12, wherein said cover sheets comprise paper.

14. The gypsum board of claim 10, wherein said trimetaphosphate compound is selected from the group consisting of sodium trimetaphosphate, lithium trimetaphosphate, potassium trimetaphosphate, ammonium trimetaphosphate, aluminum trimetaphosphate, and mixtures thereof.

15. The gypsum board of claim 10, wherein said trimetaphosphate is sodium trimetaphosphate.

16. The gypsum board of claim 10, wherein said gypsum board has a shrinkage of less than about 0.06 inch per four foot width and less than about 0.30 inch per twelve foot length, as determined according to ASTM C473-95.

17. The gypsum board of claim 10, said gypsum board having 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.

22. The gypsum board of claim 10, wherein said gypsum board further comprises a pregelatinized starch.

23. The gypsum board of claim 22, wherein the amount of pregelatinized starch is from about 0.08 to about 0.5 percent by weight of the calcined gypsum.

24. The gypsum board of claim 23, wherein the amount of pregelatinized starch is from about 0.16 to about 0.4 percent by weight of the calcined gypsum.

25. The gypsum board of claim 23, wherein the amount of pregelatinized starch is about 0.3 percent by weight of the calcined gypsum.

28. The gypsum board of claim 25, wherein Y is 0 in from 86 to 99 weight percent of the foaming agent.

29. The gypsum board of claim 10, wherein said set gypsum has voids uniformly distributed therein.

30. The gypsum board of claim 29, wherein said set gypsum is further formed from at least one foaming agent, having the formula:

31. The gypsum board of claim 30, wherein Y is 0 in from 86 to 99 weight percent of the foaming agent.

33. The gypsum board of claim 29, wherein the set gypsum is further formed from a pregelatinized starch.

34. Gypsum board comprising an interlocking matrix of set gypsum and at least one material selected from the group consisting of:

phosphoric acids, each of which comprises 1 or more phosphoric acid units; and

compounds of condensed phosphates, each of which comprises 2 or more phosphate units, said gypsum board having a sag resistance as determined according to ASTM C473-95 of less than about 0.1 inch per two foot length of said board.

35. A composite board comprising an interlocking matrix of set gypsum, a reinforcing material and at least one enhancing material selected from the group consisting of;

phosphoric acids, each of which comprises 1 or more phosphoric acid units; and

compounds of condensed phosphates, each of which comprises 2 or more phosphate units, said composite board having a sag resistance as determined according to ASTM C473-95 of less than about 0.1 inch per two foot length of said board.

36. A composite board comprising an interlocking matrix of set gypsum, host particles, and at least one enhancing material, wherein at least a portion of the set gypsum is positioned in and about accessible voids in the host particles, said board having a sag resistance as determined according to ASTM C473-95 of less than about 0.1 inch per two foot length of said board, said enhancing materials selected from the group consisting of:

phosphoric acids, each of which comprises 1 or more phosphoric acid units; and

compounds of condensed phosphates, each of which comprises 2 or more phosphate units.

37. A set gypsum-containing acoustical tile comprising an interlocking matrix of set gypsum, mineral wool and at least one enhancing material selected from the group consisting of:

phosphoric acids, each of which comprises 1 or more phosphoric acid units; and

compounds of condensed phosphates, each of which comprises 2 or more phosphate units, said acoustical tile having a sag resistance as determined according to ASTM C473-95 of less than about 0.1 inch per two foot length of said tile.

38. A set gypsum-containing acoustical tile comprising an interlocking matrix of set gypsum, expanded perlite particles, a fiber reinforcing agent, and at least one enhancing material selected from the group consisting of phosphoric acids, each of which comprises 1 or more phosphoric acid units;

and compounds of condensed phosphates, each of which comprises 2 or more phosphate units, said acoustical tile having a sag resistance as determined according to ASTM C473-95 of less than about 0.1 inch per two foot length of said tile.

39. A set gypsum-containing machinable product comprising a starch, particles of a water-redispersible polymer, an interlocking matrix of set gypsum, and at least one enhancing material selected from the group consisting of:

phosphoric acids, each of which comprises I or more phosphoric acid units; and

compounds of condensed phosphates, each of which comprises 2 or more phosphate units.

40. A gypsum board comprising a core of material sandwiched between cover sheets, wherein the core comprises an interlocking matrix of set gypsum, said board having been prepared by a method comprising:

forming or depositing a mixture between the cover sheets, wherein the mixture comprises a calcium sulfate material, water, and 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 the interlocking matrix of set gypsum,

the enhancing material or materials having been included in the mixture in an amount such that 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.