Claims
- 1. A method for preparing a nonwoven fibrous web comprising a) extruding a stream of filaments from a die having a known width and thickness; b) directing the stream of extruded filaments through a processing chamber that is defined by two narrowly separated walls that are parallel to one another, parallel to said width of the die, and parallel to the longitudinal axis of the stream of extruded filaments; c) intercepting the stream of filaments passed through the processing chamber on a collector where the filaments are collected as a nonwoven fibrous web; and d) selecting a spacing between the walls of the processing chamber that causes the stream of extruded filaments to spread and be collected as a functional web at least 50 millimeters wider than said width of the die.
- 2. A method of claim 1 in which the processing chamber defined by the two parallel walls is open to the ambient environment at its longitudinal sides.
- 3. A method of claim 1 in which the width of the walls in a direction transverse to the direction of filament travel is greater at points downstream of the filament travel than upstream points.
- 4. A method of claim 3 in which the processing chamber is closed to the ambient environment over at least part of the length of its longitudinal sides.
- 5. A method of claim 1 in which the parallel walls converge toward one another in the direction of filament travel.
- 6. A method of claim 1 in which the functional web collected is at least 100 millimeters wider than said width of the die.
- 7. A method of claim 1 in which the collected functional web is at least 200 millimeters wider than said width of the die.
- 8. A method of claim 1 in which the filaments spread to a width at least 50% greater than said width of the die before they reach the collector.
- 9. A method of claim 1 in which the filaments spread to a width at least two times said width of the die before they reach the collector.
- 10. A method of claim 1 in which the stream of filaments forms a lofty nonwoven web having a thickness of at least 5 mm and a loft of at least 10 cc/gram.
- 11. A method of claim 1 in which the solidity of the extruded filaments entering the processing chamber is controlled so that the filaments are autogenously bondable when collected on the collector.
- 12. A method of claim 1 in which at least one of the walls defining the processing chamber is instantaneously movable toward and away from the other wall and is subject to movement means for providing instantaneous movement during passage of the filaments.
- 13. A method for preparing a nonwoven fibrous web comprising a) extruding a stream of filaments from a die having a known width and thickness; b) directing the stream of extruded filaments through a processing chamber that is defined by two narrowly separated walls that are parallel to one another, parallel to said width of the die, and parallel to the longitudinal axis of the stream of extruded filaments; the processing chamber including air knives that exert a pulling force on the filaments in the direction of travel through the processing chamber; the parallel walls converging toward one another in the direction of filament travel at a point downstream from the air knives, and the processing chamber being open to the ambient environment at its longitudinal sides; c) intercepting the stream of filaments passed through the processing chamber on a collector where the processed filaments are collected as a nonwoven fibrous web; and d) selecting a spacing between the walls of the processing chamber that causes the stream of extruded filaments to spread and be collected as a functional web at least 100 millimeters wider than said width of the die.
- 14. A method of claim 13 in which the collected functional web has a width at least 200 millimeters greater than said width of the die.
- 15. A method of claim 13 in which the collected functional web has a width at least 50 percent greater than the width of said die.
- 16. A method of claim 13 in which at least one of the walls defining the processing chamber is instantaneously movable toward and away from the other wall and is subject to movement means for providing instantaneous movement during passage of the filaments.
- 17. A method for preparing a nonwoven fibrous web comprising a) extruding a stream of filaments from a die having a known width; b) directing the stream of extruded filaments through a processing chamber that is defined by two narrowly separated walls that are parallel to one another, parallel to said width of the die, and parallel to the longitudinal axis of the stream of extruded filaments; the processing chamber including air knives exerting a pulling force on the filaments in the direction of filament travel; c) intercepting the stream of filaments on a collector where the processed filaments are collected as nonwoven fibrous web; and d) selecting a spacing between the walls of the processing chamber, and arranging those walls to diverge away from one another in the direction of filament travel over a main length of the processing chamber downstream from the air knives, whereby to cause the stream of extruded filaments to have a selected width narrower than said width of the die before the stream reaches the collector.
- 18. A fibrous nonwoven web comprising a collected mass of fibers prepared by the method of claim 1.
- 19. A web of claim 18 in which the collected mass of fibers is at least 5 mm thick and has a loft of at least 10 cc/g.
- 20. A web of claim 18 in which fibers of the collected mass are autogenously bonded together.
- 21. A web of claim 18 in which the collected mass of fibers in the fibrous nonwoven web comprises only fibers that traveled within the processing chamber over the length of the chamber.
- 22. A fibrous nonwoven web comprising a collected mass of fibers prepared by a method of claim 13.
- 23. A web of claim 22 in which the collected mass of fibers is at least 5 mm thick and has a loft of at least 10 cc/g.
- 24. A web of claim 22 in which fibers of the collected mass are autogenously bonded together.
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application Ser. No. 09/835,904, filed Apr. 16, 2001, which itself was a continuation-in-part of application Ser. No. 09/716,786, filed Nov. 20, 2000.
Continuation in Parts (2)
|
Number |
Date |
Country |
Parent |
09835904 |
Apr 2001 |
US |
Child |
10151781 |
May 2002 |
US |
Parent |
09716786 |
Nov 2000 |
US |
Child |
09835904 |
Apr 2001 |
US |