Reduced dust acoustic panel

• US 20080060871A1
• Filed: 09/07/2006
• Published: 03/13/2008
• Est. Priority Date: 09/07/2006
• Status: Active Grant

• Current Assignee: USG Interiors Incorporated (GEBR Knauf Verwaltungsgesellschaft KG)
• Original Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Inventors: Englert, Mark H., Immordino, Salvatore C.
• Granted Patent: US 7,503,430 B2
• Time in Patent Office: Days
• US Class Current: 181/294
• CPC Class Codes: B28B 19/0092 to webs, sheets or the like, e.g. of paper, cardboard
• CPC Class Codes: C04B 14/185 expanded
• CPC Class Codes: C04B 14/204 expanded
• CPC Class Codes: C04B 16/08 porous, e.g. expanded polystyrene beads or microballoons
• CPC Class Codes: C04B 18/241 Paper, e.g. waste paper; Paper pulp
• CPC Class Codes: C04B 2103/0071 Phase-change materials, e.g. latent heat storage materials used in concrete compositions
• CPC Class Codes: C04B 2103/0075 Anti-dusting agents
• 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 24/32 Polyethers, e.g. alkylphenol polyglycolether
• CPC Class Codes: C04B 28/14 containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: E04B 9/001 characterised by provisions for heat or sound insulation
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

An acoustical panel includes an acoustical layer has an interlocking matrix of calcium sulfate dihydrate, polyethylene glycol and at least one of the group fibers, a lightweight aggregate and mixtures thereof. The acoustical layer has voids in the interlocking matrix that are configured to absorb sound. The polyethylene glycol is selected to agglomerate dust at temperatures generated by friction when panel is cut.

A method of making the acoustical panel includes making a slurry comprising calcium sulfate hemihydrate, polyethylene glycol, water and at least one of the group consisting of a lightweight aggregate, fibers and combinations thereof. Foam is added to the slurry, preferably at the mixer discharge. A continuous strip of acoustical layer material is formed from the slurry. The acoustical panels are formed by cutting the strip into individual panels. Finally, the partially hydrated calcium sulfate hemihydrate is allowed to fully set.

Claims

1. An acoustical panel comprising an acoustical layer comprising an interlocking matrix of calcium sulfate dihydrate, a dedusting agent and at least one of the group consisting of fibers, a lightweight aggregate and mixtures thereof, wherein voids in said interlocking matrix are configured to absorb sound and wherein said dedusting agent is selected to agglomerate dust at temperatures generated by friction when said panel is cut.

2. The panel of claim 1 wherein said dedusting agent has a melting point less than 55°

C.

3. The panel of claim 1 wherein said fibers comprise paper.

4. The panel of claim 1 wherein said calcium sulfate hemihydrate dihydrate is present in concentrations of at least 85% by weight.

5. The panel of claim 1 wherein said fibers are present in concentrations of less than 3% by weight of the acoustical panel.

6. The panel of claim 1 wherein said lightweight aggregate is present in concentrations of less than 3% by weight of the acoustical panel.

7. The panel of claim 1 wherein said lightweight aggregate is at least one of the group consisting of expanded vermiculite, expanded perlite and chopped expanded polystyrene.

8. The panel of claim 1, further comprising at least one backing sheet.

9. The panel of claim 1 wherein said backing sheet comprises paper.

10. The panel of claim 1, further comprising a densified layer being more dense then said acoustical layer.

11. The panel of claim 10, further comprising a backing sheet.

12. The panel of claim 11 wherein said densified layer is positioned between said acoustical layer and said backing layer.

13. The panel of claim 1 further comprising a scrim sheet.

14. The panel of claim 13 wherein said scrim sheet comprises a multi-ply paper sheet.

15. The panel of claim 14, wherein said panel comprises said acoustical layer, said scrim layer, said densified layer and said backing layer positioned in that order.

16. The panel of claim 14, wherein said panel comprises said said scrim layer, acoustical layer, said densified layer and said backing layer positioned in that order.

17. The panel of claim 1 having a void volume of at least 35% of the panel volume.

18. The panel of claim 17 having a void volume of at least 45% of the panel volume.

19. The panel of claim 1 further comprising an enhancing material comprising at least one of the group consisting of an ammonium polyphosphate, a trimetaphosphate compound, a tetrametaphosphate compound, a hexametaphosphate compound and combinations thereof.

20. The panel of claim 1 further comprising at least one of the group consisting of a set accelerator, a water reducing agent and combinations thereof.

21. A slurry for making an acoustical panel consisting essentially of calcium sulfate hemihydrate, reinforcing fibers, a lightweight aggregate and polyethylene glycol.

22. A method of making an acoustical panel comprising

making a slurry comprising calcium sulfate hemihydrate, a dedusting agent, water and at least one of the group consisting of a lightweight aggregate, fibers and combinations thereof;

adding foam to the slurry;

forming a continuous strip of the slurry of acoustical layer material;

cutting the strip to form the acoustical panel; and

allowing the calcium sulfate hemihydrate to set.

23. The method of claim 22 further comprising drying the panel.

24. The method of claim 22 further comprising positioning a scrim layer to receive the slurry and wherein the continuous strip of said forming step is formed by distributing the slurry over the scrim layer.

25. The method of claim 22 further comprising dividing the slurry into a main stream and a slip stream prior to the forming step;

making a densified layer from the slip stream; and

wherein the continuous strip of said forming step is formed by distributing the slurry over the densified layer.