Sound absorptive multilayer composite

• US 20040231915A1
• Filed: 07/01/2004
• Published: 11/25/2004
• Est. Priority Date: 01/02/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Liu, Xiaohe, Thompson, Delton R. Jr.
• Granted Patent: US 7,320,739 B2
• Time in Patent Office: Days
• US Class Current: 181/290
• CPC Class Codes: B01D 2325/26 Electrical properties
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 67/0088 Physical treatment with compounds, e.g. swelling, coating or impregnation
• CPC Class Codes: B01D 67/009 with wave-energy, particle-radiation or plasma
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B32B 2255/02 on fibrous or filamentary layer
• CPC Class Codes: B32B 2262/0276 Polyester fibres
• CPC Class Codes: B32B 2262/101 Glass 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 2266/025 Polyolefin
• CPC Class Codes: B32B 2266/0278 Polyurethane
• CPC Class Codes: B32B 2266/06 Open cell foam
• CPC Class Codes: B32B 2307/102 Insulating
• CPC Class Codes: B32B 2307/724 Permeability to gases, adsorption
• CPC Class Codes: B32B 2307/7242 Non-permeable
• CPC Class Codes: B32B 2605/08 Cars
• CPC Class Codes: B32B 27/065 of foam
• CPC Class Codes: B32B 27/12 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 5/02 : characterised by structural features of a fibrous or filamentary layer layer formed of metallic wires B32B15/02; layer formed of natural mineral fibres B32B19/02; layer formed of wood fibres B32B21/02
• CPC Class Codes: B32B 5/04 : characterised by a layer being specifically extensible by reason of its structure or arrangement , e.g. by reason of the chemical nature of the fibres or filaments
• CPC Class Codes: B32B 5/18 : characterised by features of a layer of foamed material
• CPC Class Codes: B32B 5/24 : one layer being a fibrous or filamentary layer
• CPC Class Codes: B32B 5/245 : another layer next to it being a foam layer
• CPC Class Codes: B32B 5/32 : at least two layers being foamed and next to each other
• CPC Class Codes: B32B 7/022 : Mechanical properties
• CPC Class Codes: B32B 7/12 : using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B60R 13/011 : for internal load compartments, e.g. car trunks
• CPC Class Codes: B60R 13/02 : Internal Trim mouldings ; Internal Ledges; Wall liners for passenger compartments; Roof liners B60R13/01 takes precedence ; padded linings for the vehicle interior B60R21/04; arrangements or adaptations of floor mats or carpets in vehicles B60N3/04; internal lining for trains B61D17/18
• CPC Class Codes: B60R 13/0256 : Dashboard liners
• CPC Class Codes: B60R 13/0815 : Acoustic or thermal insulation of passenger compartments wall or roof liners integrating the insulating function B60R13/02; insulating floor mats or carpets B60N3/04
• CPC Class Codes: B60R 13/083 : for fire walls or floors
• CPC Class Codes: B60R 13/0838 : for engine compartments
• CPC Class Codes: G10K 11/162 : Selection of materials
• CPC Class Codes: G10K 11/168 : Plural layers of different materials, e.g. sandwiches
• CPC Class Codes: Y10T 156/1002 : with permanent bending or reshaping or surface deformation of self sustaining lamina

Abstract

A sound absorptive multilayer composite having an air-impermeable barrier, an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about ⅓ the final composite thickness, an air-permeable open cell foam or fibrous pad having an airflow resistance less than about 2000 mks Rayls and a thickness at least about {fraction (1/10)} the final composite thickness and a semipermeable airflow-resistive membrane having an airflow resistance of about 500 to about 4000 mks Rayls can provide improved acoustic performance. For example, existing vehicular headliner designs may be improved by adding a properly chosen and properly positioned semipermeable airflow-resistive membrane, a properly chosen and properly positioned air- impermeable barrier, or a properly chosen and properly positioned open cell foam layer.

Claims

1. A sound absorptive multilayer composite comprising in order:

a) a semipermeable airflow-resistive membrane having an airflow resistance of about 500 to about 4000 mks Rayls,

b) an air-permeable open cell foam or fibrous pad having an airflow resistance less than about 2000 mks Rayls and a thickness at least about {fraction (1/10)} the total composite thickness,

c) an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about ⅓

the total composite thickness, and

d) an air-impermeable barrier.

2. A composite according to claim 1 wherein the composite has a cavity depth at least 90% of the total composite thickness, with the cavity depth being measured from the air-impermeable barrier innermost side to the membrane outermost side.

3. A composite according to claim 1 wherein the composite has a cavity depth at least 95% of the total composite thickness, with the cavity depth being measured from the air-impermeable barrier innermost side to the membrane outermost side.

4. A composite according to claim 1 wherein the membrane has an airflow resistance of about 500 to about 1500 mks Rayls.

5. A composite according to claim 1 wherein the membrane is an outermost layer of the composite.

6. A composite according to claim 1 wherein the membrane is colored or textured to provide a decorative appearance.

7. A composite according to claim 1 wherein the membrane comprises a nonwoven web.

8. A composite according to claim 1 wherein the membrane comprises knit or woven fabric comprising microdenier yarns.

9. A composite according to claim 1 wherein the membrane comprises multicomponent fibers.

10. A composite according to claim 1 wherein the membrane comprises split or splittable bicomponent fibers.

11. A composite according to claim 1 wherein the foam or fibrous pad has a thickness at least about ¼

the total composite thickness.

12. A composite according to claim 1 wherein the foam or fibrous pad has a thickness at least about ½

the total composite thickness.

13. A composite according to claim 1 wherein the foam or fibrous pad has an airflow resistance less than about 500 mks Rayls.

14. A composite according to claim 1 wherein the core has a thickness less than about ⅔

the total composite thickness.

15. A composite according to claim 1 wherein the core has a thickness less than about ½

the total composite thickness.

16. A composite according to claim 1 wherein the core has an airflow resistance less than about 2000 mks Rayls.

17. A composite according to claim 1 further comprising an outermost nonrestrictive air-permeable decorative layer adhered to the membrane.

18. A roll good comprising a spirally-wound porous laminate preform comprising a semipermeable airflow-resistive membrane having an airflow resistance of about 500 to about 4000 mks Rayls, adhered to an air-permeable open cell foam or fibrous pad having an airflow resistance less than about 2000 mks Rayls and a thickness of at least about 1 mm.

19. A roll good according to claim 18 wherein the membrane has an airflow resistance of about 500 to about 1500 mks Rayls.

20. A roll good according to claim 18 wherein the membrane is colored or textured to provide a decorative appearance.

21. A roll good according to claim 18 wherein the membrane comprises a nonwoven web.

22. A roll good according to claim 18 wherein the membrane comprises knit or woven fabric comprising microdenier yarns.

23. A roll good according to claim 18 wherein the membrane comprises multicomponent fibers.

24. A roll good according to claim 18 wherein the foam or fibrous pad has an airflow resistance less than about 500 mks Rayls.

25. A roll good according to claim 18 further comprising a thermoplastic adhesive layer adhered to the foam.

26. A roll good according to claim 18 further comprising an outermost nonrestrictive air-permeable decorative layer adhered to the membrane.

27. A roll good comprising a spirally-wound porous laminate preform comprising a nonrestrictive air-permeable decorative woven or nonwoven fabric layer, adhered to a semipermeable airflow-resistive membrane having an airflow resistance of about 500 to about 4000 mks Rayls, adhered to an air-permeable open cell foam or fibrous pad having an airflow resistance less than about 2000 mks Rayls and a thickness of at least about 1 mm, adhered to a thermoplastic adhesive layer.

28. A method for making a multilayer sound absorptive composite comprising:

a) providing a stack of layers comprising in order an air-impermeable barrier, an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about ⅓

the final composite thickness, an air-permeable open cell foam or fibrous pad having an airflow resistance less than about 2000 mks Rayls and a thickness at least about {fraction (1/10)} the final composite thickness, and a semipermeable airflow-resistive membrane having an airflow resistance of about 500 to about 4000 mks Rayls, and

b) laminating the stack of layers together under sufficient heat and pressure to form a unitary sound absorptive multilayer composite.

29. A method according to claim 28 wherein the composite has a cavity depth at least 90% of the total composite thickness, with the cavity depth being measured from the air-impermeable barrier innermost side to the membrane outermost side.

30. A method according to claim 28 wherein the composite has a cavity depth at least 95% of the total composite thickness, with the cavity depth being measured from the air-impermeable barrier innermost side to the membrane outermost side.

31. A method according to claim 28 wherein the membrane has an airflow resistance of about 500 to about 1500 mks Rayls.

32. A method according to claim 28 wherein the membrane is an outermost layer of the composite.

33. A method according to claim 28 wherein the membrane is colored or textured to provide a decorative appearance.

34. A method according to claim 28 wherein the membrane comprises a nonwoven web.

35. A method according to claim 28 wherein the membrane comprises knit or woven fabric comprising microdenier yarns.

36. A method according to claim 28 wherein the membrane comprises multicomponent fibers.

37. A method according to claim 28 wherein the membrane comprises split or splittable bicomponent fibers.

38. A method according to claim 28 wherein the foam or fibrous pad has a thickness at least about ¼

the total composite thickness.

39. A method according to claim 28 wherein the foam or fibrous pad has a thickness at least about ½

the total composite thickness.

40. A method according to claim 28 wherein the foam or fibrous pad has an airflow resistance less than about 500 mks Rayls.

41. A method according to claim 28 wherein the core has a thickness less than about ⅔

the total composite thickness.

42. A method according to claim 28 wherein the core has a thickness less than about ½

the total composite thickness.

43. A method according to claim 28 wherein the core has an airflow resistance less than about 2000 mks Rayls.

44. A method according to claim 28 wherein the stack further comprises an outermost nonrestrictive air-permeable decorative layer adjacent the membrane.