Methods of making composite nonwoven webs

Patent metadata

Field	Value
Publication number	US-11505883-B2
Application number	US-201816623690-A
Country	US
Kind code	B2
Filing date	Jun 29, 2018
Priority date	Jun 30, 2017
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

Disclosed herein are improvements to processes and equipment for the manufacture of composite nonwoven webs comprising a mixture of two or more different fibers and formed from at least two streams of air-entrained fibers. Adjacent the perimeter of an exit port of one of the fiber streams are located a series of spaced tabs and apertures. As a first stream of air-entrained fibers pass the series of tabs and apertures, vortices are formed therein. When mixed with a second stream of air-entrained fibers, the vortices within the first stream of fibers causes increased mixing of the fibers, helping to drive the first fibers deeper into the second stream of air-entrained fibers.

First claim

What is claimed is:

1. A method of making a composite nonwoven web comprising:
providing a chute having at least first and second opposed walls that extend in a cross-direction that define a passageway and passageway direction and further define an exit gap;
providing a series of spaced tabs extending outwardly from proximate the exit gap and further wherein adjacent the tabs are open spaces whereby air is allowed to flow sidewardly relative to the passageway direction;
entraining first fibers in a first stream of air and thereby forming a first stream of air-entrained fibers;
entraining second fibers in a second stream of air thereby forming a second stream of air-entrained fibers;
directing the first stream of air-entrained fibers through the passageway in the passageway direction;
directing the first stream of air-entrained first fibers through the exit gap and past the tabs thereby forming vortices in the first stream of air-entrained fibers; then
directing the second stream of air-entrained fibers such that it impinges upon the first stream of air-entrained fibers wherein the second fibers and first fibers inter-mix and form a composite stream of air-entrained fibers;
providing a moving forming surface under the exit gap;
depositing the composite stream of air-entrained fibers onto the forming surface thereby forming a nonwoven web.

2. The method of claim 1 wherein the velocity of the first stream of air-entrained fibers within the chute is greater than 50 M/second.

3. The method of claim 1 wherein the tabs have a height between about 0.2 and about 4 cm.

4. The method of claim 3 wherein the center to center distance of the tabs is between about 0.4 and about 10 cm.

5. The method of claim 1 wherein the series of tabs and open spaces form a crenulate.

6. The method of claim 1 wherein the tabs have a triangular shape.

7. The method of claim 1 wherein the series of spaced tabs extends along at least 60-100% of at least one of the first and second walls.

8. The method of claim 1 wherein the series of spaced tabs extend along at least 60-100% of both of the first and second walls.

9. The method of claim 8 wherein the series of spaced tabs are positioned beneath the entire CD length of both of said first and second walls.

10. The method of claim 8 wherein the tabs adjacent the opposed first and second walls are offset relative to one another in the machine direction.

11. The method of claim 8 wherein the tabs adjacent the opposed first and second walls are aligned with one another in the machine direction.

12. The method of claim 1 wherein the first fibers have an average length of between about 0.2 and about 3 mm.

13. The method of claim 12 wherein the first fibers comprise cellulosic fibers.

14. The method of claim 12 wherein the second fibers comprise thermoplastic polymer and are semi-molten when the second stream of air-entrained fibers impinges upon and mixes with the first stream of air-entrained fibers.

15. The method of claim 1 wherein the greater inter-mixing of the first and second streams of fibers occurs regionally whereby first fibers are regionally driven deeper into the stream of second fibers and wherein the nonwoven web formed on the forming surface has alternating first and second rows, extending in the machine direction, whereby the first region has a greater weight percentage of first fibers than the second region.

16. The method of claim 15 wherein the first rows contain at least 5% more first fibers than the second rows.

17. The method of claim 1 wherein the first fibers comprise staple length fibers and the second fibers comprise continuous fibers.

18. The method of claim 1 wherein the tabs extend at an angle +/−45 degrees relative to the passageway direction.

19. The method of claim 1 wherein the tabs do not extend directly beneath the passageway.

20. The method of claim 1 wherein the tabs are flush with an inner wall of the first or second wall and further wherein the tabs are angled away from the passageway.

Assignees

• Kimberly Clark Co

Inventors

• Haynes Bryan D

Classifications

• D04H1/492 Primary

  by fluid jet (D04H1/49 takes precedence) · CPC title

• D01D5/0985

  by means of a flowing gas (e.g. melt-blowing) · CPC title

• D04H1/56 Primary

  in association with fibre formation, e.g. immediately following extrusion of staple fibres · CPC title

• D04H1/732 Primary

  by fluid current, e.g. air-lay · CPC title

• D04H5/06

  strengthened or consolidated by welding-together thermoplastic fibres, filaments, or yarns · CPC title