Porous membrane

• US 7,686,132 B2
• Filed: 12/29/2005
• Issued: 03/30/2010
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Olson, David A., Van Dam, Gerald L.
• Primary Examiner(s): Donels; Jeffrey
• Assistant Examiner(s): LUKS, JEREMY AUSTIN
• Application Number:
  US11/321,189
• Publication Number:
  US 20070151800A1
• Time in Patent Office: 1,552 Days
• Field of Search: 181/286, 181/290, 181/291
• US Class Current: 181/286
• CPC Class Codes: B32B 2262/0253 Polyolefin fibres
• CPC Class Codes: B32B 2262/0261 Polyamide fibres
• CPC Class Codes: B32B 2262/0284 Polyethylene terephthalate [PET] or polybutylene terephthalate [PBT]
• CPC Class Codes: B32B 2262/0292 Polyurethane fibres
• CPC Class Codes: B32B 2262/12 Conjugate fibres, e.g. core/sheath or side-by-side
• CPC Class Codes: B32B 2262/14 Mixture of at least two fibres made of different materials
• CPC Class Codes: B32B 2266/06 Open cell foam
• CPC Class Codes: B32B 2307/102 Insulating
• CPC Class Codes: B32B 2307/718 Weight, e.g. weight per square meter
• CPC Class Codes: B32B 5/022 Non-woven fabric
• CPC Class Codes: B32B 5/08 the fibres or filaments of a layer being of different substances , e.g. conjugate fibres, mixture of different fibres
• CPC Class Codes: B32B 5/245 another layer next to it being a foam layer
• CPC Class Codes: B32B 5/26 another layer next to it also being fibrous or filamentary relative arrangement of fibres or filaments of different layers B32B5/12
• CPC Class Codes: E04B 1/8409 sheet-shaped
• CPC Class Codes: G10K 11/168 Plural layers of different materials, e.g. sandwiches

Abstract

A new acoustic insulating sheet material comprises in laminar assembly a) a primary sound absorbing sheet, and b) a dense porous membrane that i) has an air-flow resistance of about 5000 rayls or less and ii) has an Acoustic Value Ratio as defined herein of at least 3000. Preferably, the membrane is about 200 micrometers or less in thickness, and more preferably is about 150 micrometers or less in thickness. Also, the Acoustic Value Ratio is preferably at least 7,000. The described membrane can also be used alone to acoustically insulate a space, e.g., by mounting it in planar array over an air gap and in position to attenuate noise from a noise source.

Claims

1. An acoustic insulating sheet material comprising in laminar assembly a) a primary sound absorbing sheet, and b) a dense, porous self-sustaining membrane about 200 micrometers or less in thickness that i) has an airflow resistance of about 10,000 rayls or less and ii) has an Acoustic Value Ratio of at least 3000.

2. A sheet material of claim 1 in which the membrane has a basis weight of 100 g/m² or less.

3. A sheet material of claim 1 in which the membrane has an airflow resistance of 5000 rayls or less.

4. A sheet material of claim 1 in which the membrane comprises at least two distinctive layers of fibers.

5. A sheet material of claim 1 in which the membrane comprises a densified SMS sheet.

6. A sheet material of claim 1 in which the membrane has a thickness of 150 micrometers or less.

7. A sheet material of claim 1 in which the membrane has an Acoustic Value Ratio of at least 7,000.

8. A sheet material of claim 1 in which the membrane has a thickness of 150 micrometers or less and an Acoustic Value Ratio of at least 7,000.

9. A sheet material of claim 1 in which the membrane has a thickness of about 50 micrometers or less.

10. A sheet material of claim 1 in which the membrane has a basis weight of 50 g/m² or less.

11. A sheet material of claim 9 in which the membrane has a basis weight of 50 g/m² or less.

12. An acoustic insulating sheet material comprising in laminar assembly a) a primary sound absorbing sheet, and b) a dense porous fibrous self-sustaining membrane that i) is about 200 micrometers or less in thickness, ii) has a basis weight of 100 g/m² or less, iii) has an airflow resistance of about 5000 rayls or less and iv) has an Acoustic Value Ratio of at least 7,000.

13. A sheet material of claim 12 in which the membrane is 150 micrometers or less in thickness.

14. A sheet material of claim 12 in which the membrane has an Acoustic Value Ratio of at least 10,000.

15. A sheet material of claim 12 in which the membrane has an airflow resistance of about 2000 rayls or less.

16. A sheet material of claim 12 in which the membrane comprises a densified SMS sheet.

17. A method for acoustically insulating a space comprising mounting a membrane in a planar array over an air gap and in position to attenuate noise from a noise source, the membrane being a dense porous self-supporting membrane having a thickness of 200 micrometers or less, an airflow resistance of about 5000 rayls or less and an Acoustic Value Ratio of at least 3000.

18. A method of claim 17 in which the membrane has a thickness of about 150 micrometers or less.

19. A method of claim 17 in which the membrane has an Acoustic Value Ratio of at least 7,000.

20. A method of claim 17 comprising mounting a more lofty nonwoven fibrous sheet material in laminar assembly with the membrane.