Acoustical gypsum board panel and method of making it

• US 20080299413A1
• Filed: 05/31/2007
• Published: 12/04/2008
• Est. Priority Date: 05/31/2007
• Status: Active Grant

• Current Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Original Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Inventors: Englert, Mark H., Yu, Qiang, Brown, Martin W., Song, W. David, Stevens, Richard B.
• Granted Patent: US 8,057,915 B2
• Time in Patent Office: Days
• US Class Current: 428/689
• CPC Class Codes: B28B 19/0092 to webs, sheets or the like, e.g. of paper, cardboard
• CPC Class Codes: B32B 2305/30 Fillers, e.g. particles, powders, beads, flakes, spheres, chips
• CPC Class Codes: B32B 2307/10 having particular acoustical properties
• CPC Class Codes: B32B 2315/18 Plaster
• CPC Class Codes: B32B 2607/00 Walls, panels
• CPC Class Codes: C04B 14/185 expanded
• CPC Class Codes: C04B 20/002 Hollow or porous granular materials
• CPC Class Codes: C04B 20/0048 Fibrous materials
• CPC Class Codes: C04B 20/0076 characterised by the grain distribution
• CPC Class Codes: C04B 20/1018 with organic materials pigments or dyes C04B20/1096
• CPC Class Codes: C04B 2103/408 Dispersants
• CPC Class Codes: C04B 2111/0062 Gypsum-paper board like materials
• CPC Class Codes: C04B 2111/52 Sound-insulating materials
• CPC Class Codes: C04B 22/16 containing phosphorus in the anion, e.g. phosphates
• CPC Class Codes: C04B 24/38 Polysaccharides or derivatives thereof C04B24/243 takes precedence
• CPC Class Codes: C04B 28/145 Calcium sulfate hemi-hydrate with a specific crystal form
• CPC Class Codes: Y10T 442/20 Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
• CPC Class Codes: Y10T 442/2738 Coating or impregnation intended to function as an adhesive to solid surfaces subsequently associated therewith
• CPC Class Codes: Y10T 442/361 At least one layer is derived from water-settable material [e.g., cement, gypsum, etc.]
• CPC Class Codes: Y10T 442/665 Including a layer derived from a water-settable material [e.g., cement, gypsum, etc.]

Abstract

The acoustical product of the present invention comprises an acoustical product including a matrix of calcium sulfate dihydrate crystals and expanded perlite distributed throughout the matrix. The expanded perlite has a particle size distribution with at least 10% of the perlite having a particle diameter of 700 microns or more, and the amount of expanded perlite to calcium sulfate dihydrate is about 35% to about 75% by weight, based upon the dry weight of the calcium sulfate dihydrate. A dispersing agent and glass fibers having a particle length of about ¼ inch to about 1 inch are dispersed throughout the gypsum matrix.

Claims

1. An acoustical product comprising:

a matrix of calcium sulfate dihydrate crystals;

a lightweight aggregate distributed throughout the matrix, said lightweight aggregate having a particle size distribution with at least 10% of the lightweight aggregate having a particle diameter of 700 microns or more, and wherein the amount of lightweight aggregate to calcium sulfate dihydrate is about 35% to about 75% by weight, based upon the dry weight of the calcium sulfate dihydrate;

a dispersing agent; and

long reinforcing fibers.

2. The product of claim 1 wherein said long reinforcing fibers have a particle length of about ¼

inch to about 1 inch.

3. The product of claim 1 wherein said lightweight aggregate is expanded perlite.

4. The product of claim 3 wherein said expanded perlite is treated with a coating.

5. The product of claim 4 wherein said coating comprises at least one of the group consisting of a silicone compound, a film-forming, thermoplastic polymer and combinations thereof.

6. The product of claim 1 further comprising a strength enhancing additive.

7. The product of claim 6 wherein said strength enhancing additive is a trimetaphosphate compound.

8. The product of claim 1 further comprising at least one of a starch, a binder and a dispersant.

9. The product of claim 1 wherein said product is an acoustical ceiling product.

10. The product of claim 1 wherein said product is an acoustical gypsum board panel.

11. The product of claim 1 wherein said expanded perlite has a bimodal particle size distribution.

12. The product of claim 1 wherein said calcium sulfate hemihydrate comprises the alpha form or beta form.

13. The product of claim 1 wherein said acoustical product further comprises an acoustically transparent facing on a front face and a paper facing on a back face.

14. A method of making an acoustical product comprising:

obtaining an expanded perlite having a particle size distribution with at least 10% of the perlite having a particle diameter of 700 microns or more;

obtaining a calcium sulfate hemihydrate;

combining dry ingredients, including said calcium sulfate hemihydrate and said perlite;

mixing the dry ingredients with water to form a slurry;

inserting foam into the slurry;

forming the acoustical product from the slurry; and

allowing the slurry to set.

15. The method of claim 14 further comprising coating the perlite with a coating comprising one of the group consisting of a silicone compound, a film-forming, thermoplastic polymer and mixtures thereof.

16. The method of claim 14 wherein said inserting step further comprises inserting the foam into the slurry at the mixer outlet.

17. The method of claim 14 further comprising adding an anti-sag additive to the slurry.

18. The method of claim 14 further comprising adding at least one of the group consisting of a starch, a binder and a dispersant.

19. The method of claim 14 further comprising sandwiching said slurry between two facing sheets.

20. The method of claim 19 wherein one or both of said two facing sheets are acoustically transparent.

21. The method of claim 20 wherein one of said two facing sheets is acoustically transparent and the other of said two facing sheets is paper.