Acoustical insulating web

Abstract

A method for attenuating sound waves passing from a source area to a receiving area comprises the steps of providing a nonwoven acoustical insulation web comprising thermoplastic fibers, the web having an average effective fiber diameter of less than about 15 microns, a density of less than about 50 kg/m 3 , and an air pressure drop across the web of at least about 1 Mm water at a flow rate of about 32 liters/min.; and positioning the web between the source area and the receiving area such that a major face of the web intercepts and thereby attenuates sound waves passing from the source area to the receiving area. Also, a laminate adapted to be applied to the inner panel of a vehicle door comprises the web and a second layer, such as a scrim, nonwoven fabric, film, or foil, laminated thereto. The laminate can be applied to the inner panel of a vehicle door so that the second layer provides water barrier protection and the web provides acoustical insulation. Also, a nonwoven acoustical insulation web comprising thermoplastic fibers, the web having an average effective fiber diameter of less than about 15 microns, a density of less than about 20 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min. The web typically comprises melt-blown microfibers and crimped bulking fibers in a weight percent ratio of about 40:60 to about 95:5, respectively.

What is claimed is: 
     
       1. A method for attenuating sound waves .Iadd.in a vehicle, said sound waves .Iaddend.passing from a source area to a receiving area, comprising the steps of: a) providing a nonwoven acoustical insulation web comprising thermoplastic fibers, said web having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min.; and   b) positioning said web between said source area and said receiving area such that a major face of said web intercepts and thereby attenuates sound waves passing from said source area to said receiving area.   
     
     
       2. The method of claim 1 wherein the average effective fiber diameter of said web is about 5 to about 10 microns. 
     
     
       3. The method of claim 1 wherein the density of said web is less than about 20 kg/m 3 . 
     
     
       4. The method of claim 1 wherein the density of said web is less than about 10 kg/m 3 . 
     
     
       5. The method of claim 1 wherein the pressure drop is about 3 mm water to about 10 mm water at a flow rate of about 32 liters/min. 
     
     
       6. The method of claim 1 wherein said fibers comprise melt-blown microfibers. 
     
     
       7. The method of claim 1 wherein said fibers comprise a mixture of melt-blown microfibers and crimped bulking fibers. 
     
     
       8. The method of claim 7 wherein said melt-blown microfibers and crimped bulking fibers are present in a weight percent ratio of about 40:60 to about 95:5, respectively. 
     
     
       9. The method of claim 1 wherein said web comprises very fine denier staple fibers. 
     
     
       10. The method of claim 9 wherein said very fine denier staple fibers have a denier of about 2 or less. 
     
     
       11. The method of claim 9 wherein said web further comprises additional staple fibers selected from the group consisting of binder fibers and static discharge fibers. 
     
     
       12. The method of claim 11 wherein said very fine denier staple fibers comprise at least about 85 weight percent of said web. 
     
     
       13. The method of claim 1 further comprising the step of laminating a second layer to said web to form a laminate prior to said web positioning step. 
     
     
       14. The method of claim 13 wherein said second layer is selected from the group consisting of scrim, nonwoven fabric, film, and foil. 
     
     
       15. The method of claim 14 wherein said second layer comprises a thermoplastic film. 
     
     
       16. The method of claim 13 wherein said web is oriented during said web positioning step so that a major face of said web faces the source areas and said second layer faces the receiving area. 
     
     
       17. The method of claim 14 wherein said fibers comprise melt-blown microfibers and crimped bulking fibers. 
     
     
       18. The method of claim 17 wherein said melt-blown microfibers and crimped bulking fibers are present in a weight percent ratio of about 40:60 to about 95:5, respectively. 
     
     
       19. The method of claim 14 wherein the average effective fiber diameter of said web is about 5 to about 10 microns. 
     
     
       20. The method of claim 1 wherein said web comprises microfiber microwebs. 
     
     
       21. A laminate comprising: a) a nonwoven acoustical insulation web comprising thermoplastic fibers, said web having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min.; and   b) a second layer laminated to said web, said laminate being applied to the inner panel of a vehicle door.   
     
     
       22. The laminate of claim 21 wherein said second layer is selected from the group consisting of scrim, nonwoven fabric, film, and foil. 
     
     
       23. The laminate of claim 22 wherein said second layer comprises a thermoplastic film. 
     
     
       24. The laminate of claim 21 wherein the average effective fiber diameter of said about 5 to about 10 microns. 
     
     
       25. The laminate of claim 21 wherein the density of said web is less than about 20 kg/m 3 . 
     
     
       26. The laminate of claim 21 wherein the density of said web is less than about 10 kg/m 3 . 
     
     
       27. The laminate of claim 21 wherein the pressure drop is about 3 mm water to about 10 mm water at a flow rate of about 32 liters/min. 
     
     
       28. The laminate of claim 21 wherein said fibers comprise melt-blown microfibers. 
     
     
       29. The laminate of claim 21 wherein said fibers comprise a mixture of melt-blown microfibers and crimped bulking fibers. 
     
     
       30. The laminate of claim 29 wherein said meltblown microfibers and crimped bulking fibers are present in a weight percent ratio of about 40:60 to about 95:5, respectively. 
     
     
       31. The laminate of claim 21 wherein said web comprises very fine denier staple fibers. 
     
     
       32. The laminate of claim 31 wherein said very fine denier staple fibers have a denier of about 2 or less. 
     
     
       33. The laminate of claim 31 wherein said web further comprises additional staple fibers selected from the group consisting of binder fibers and static discharge fibers. 
     
     
       34. The laminate of claim 31 wherein said very fine denier staple fibers comprise at least about 85 weight percent of said web. 
     
     
       35. The laminate of claim 21 wherein said web comprises microfiber microwebs. 
     
     
       36. The laminate of claim 21 wherein said laminate comprises pressure molded reduced thickness areas along its outer periphery, said reduced thickness areas having a thin gauge relative to other portions of said laminate. 
     
     
       37. The laminate of claim 36 wherein said second layer is selected from the group consisting of scrim, nonwoven fabric, film, and foil. 
     
     
       38. The laminate of claim 36 wherein said second layer comprises a thermoplastic film. 
     
     
       39. A method for preventing sound and water from entering a vehicle interior, comprising the steps of: a) providing a laminate comprising a nonwoven acoustical insulation web and a second layer laminated to said web, said web comprising thermoplastic fibers and having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min.; and   b) securing sad laminate to a panel of a vehicle to attenuate sound waves which contact a major face of said web of said laminate and prevent the passage of water through the panel and into the vehicle interior.   
     
     
       40. A process for manufacturing a vehicle door, comprising the steps of: a) providing a vehicle door having outer and inner panels secured together with a space therebetween for accommodating various mechanisms, the inner panel comprising a recessed area comprising at least one opening;   b) providing a laminate comprising a nonwoven acoustical insulation web and a second layer laminated to said web, said web comprising thermoplastic fibers and having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min.; and   c) securing said laminate to the inner panel with said second layer of said laminate disposed adjacent to the inner panel so that said second layer can provide water barrier protection and said web can provide acoustical insulation.   
     
     
       41. The process of claim 40 wherein said second layer is a thermoplastic film. . .42. A nonwoven acoustical insulation web comprising thermoplastic fibers, said web having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 20 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min..!.. .43. The web of claim 42 wherein the average effective fiber diameter of said web is about 5 to about 10 microns..!.. .44. The web of claim 42 wherein the density of said web is less than about 10 kg/m 3 ..!.. .45. The web of claim 42 wherein the pressure drop is about 3 mm water to about 10 mm water at a flow rate of about 32 liters/min..!.. .46. The web of claim 42 wherein said fibers comprise melt-blown microfibers..!.. .47. The web of claim 42 wherein said fibers comprise a mixture of melt-blown microfibers and crimped bulking fibers..!.. .48. The web of claim 47 wherein said melt-blown microfibers and crimped bulking fibers are present in a weight percent ratio of about 40:60 to about 95:5, is respectively..!.. .49. The web of claim 42 wherein said web comprises very fine denier staple fibers..!.. .50. The web of claim 47 wherein said very fine denier staple fibers have a denier of about 2 or less..!.. .51. The web of claim 50 further comprising additional staple fibers selected from the group consisting of binder fibers and static discharge fibers..!.. .52. The web of claim 51 wherein said very fine denier staple fibers comprise at least about 85 weight percent of said web..!.. .53. The web of claim 40 wherein said web 
     
     
        comprises microfiber microwebs..!..Iadd.54.  A laminate comprising a nonwoven acoustical insulation web applied to the inner panel of a vehicle door, said web comprising thermoplastic fibers, said web having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min. .Iaddend..Iadd.55. A method for preventing sound and water from entering a vehicle interior, comprising the steps of: a) providing a laminate comprising a nonwoven acoustical insulation web and a water barrier layer laminated to said web, said web comprising thermoplastic fibers and having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min., said laminate being adapted for placement on an interior panel of a vehicle in a single step; and   b) securing said laminate to a panel of a vehicle to attenuate sound waves which contact a major face of said web of said laminate and prevent the passage of water through the panel and into the vehicle interior. .Iaddend..Iadd.56. A process for manufacturing a vehicle door, comprising the steps of:   a) providing a vehicle door having outer and inner panels secured together with a space therebetween for accommodating various mechanisms, the inner panel comprising a recessed area comprising at least one opening;   b) providing a laminate comprising a nonwoven acoustical insulation web and a water barrier layer laminated to said web, said web comprising thermoplastic fibers and having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min., said laminate being adapted for placement on the inner panel in a single step; and   c) securing said laminate to the inner panel with said water barrier layer of said laminate disposed adjacent to the inner panel so that said water barrier layer can provide water barrier protection and said web can provide acoustical insulation. .Iaddend..Iadd.57. The process of claim 56 wherein said water barrier layer is a thermoplastic film. .Iaddend..Iadd.58. A method for attenuating sound waves in a small appliance, said sound waves passing from a source area to a receiving area, comprising the steps of:   a) providing a nonwoven acoustical insulation web comprising thermoplastic fibers, said web having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min.; and   b) positioning said web between said source area and said receiving area such that a major face of said web intercepts and thereby attenuates sound waves passing from said source area to said receiving area. .Iaddend..Iadd.59. A method for attenuating sound waves in an article used in architectural applications, said sound waves passing from a source area to a receiving area, comprising the steps of:   a) providing a nonwoven acoustical insulation web comprising thermoplastic fibers, said web having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min.; and   b) positioning said web between said source area and said receiving area such that a major face of said web intercepts and thereby attenuates sound waves passing from said source area to said receiving area. .Iaddend..Iadd.60. A method for attenuating sound waves in an article used for transportation, said sound waves passing from a source area to a receiving area, comprising the steps of:   a) providing a nonwoven acoustical insulation web comprising thermoplastic fibers, said web having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min.; and   b) positioning said web between said source area and said receiving area such that a major face of said web intercepts and thereby attenuates sound waves passing from said source area to said receiving area. .Iaddend..Iadd.61. The method of claim 60 wherein said article comprises a vehicle. .Iaddend..Iadd.62. The method of claim 60 wherein said article comprises an airplane. .Iaddend..Iadd.63. The method of claim 60 wherein said article comprises a train. .Iaddend..Iadd.64. A laminate comprising a nonwoven acoustical insulation web comprising thermoplastic fibers,   said web having an average effective fiber diameter of less than about 15 microns, a thickness of at least about 0.5 cm, a density of less than about 50 kg/m 3 , and a pressure drop of at least about 1 mm water at a flow rate of about 32 liters/min.,   said laminate comprising pressure molded reduced thickness areas alone its outer periphery, said reduced thickness areas having a thin gauge relative to other portions of said laminate. .Iaddend..Iadd.65. The laminate of claim 64 further comprising a second layer laminated to said web.   
     
     
        .Iaddend..Iadd.66.  The laminate of claim 65 wherein said second layer is selected from the croup consisting of scrim, nonwoven fabric, film, and foil. .Iaddend..Iadd.67. The laminate of claim 65 wherein said second layer comprises a thermoplastic film. .Iaddend.