Acoustical gypsum board panel and method of making it

• US 8,057,915 B2
• Filed: 05/31/2007
• Issued: 11/15/2011
• 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: Stevens, Richard B., Englert, Mark H., Yu, Qiang, Brown, Martin W., Song, W. David
• Primary Examiner(s): Choi; Peter Y
• Application Number:
  US11/807,980
• Publication Number:
  US 20080299413A1
• Time in Patent Office: 1,629 Days
• Field of Search: 442/149, 442/256, 442/59, 442/386, 428/688, 428/689, 428/703, 264/212, 156/39, 106/698, 106/772
• US Class Current: 428/688
• 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 bimodal particle size distribution curve having a first maximum in the range of 500 to 2000 microns and a second maximum in the range of 10 to 100 microns, and wherein the ratio of lightweight aggregate to calcium sulfate dihydrate ranges from about 35% to about 75% by weight, based upon the dry weight of the calcium sulfate dihydrate;

a foaming agent comprising at least one of alkyl ether sulfates and sodium laureth sulfates;

a dispersing agent; and

long reinforcing fibers distributed throughout said calcium sulfate dihydrate matrix.

2. The product of claim 1 wherein said long reinforcing fibers have a fiber 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 calcium sulfate dihydrate comprises hydrated calcium sulfate hemihydrate of the alpha form or beta form.

12. 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.

13. The product of claim 1 wherein said bimodal particle size distribution comprises at least 20% by weight of the aggregate having a particle size of 700 microns or larger.

14. The product of claim 13 wherein said bimodal particle size distribution comprises at least 25% by weight of the aggregate having a particle size of 700 microns or larger.