Manufacture of spunbonded nonwoven from continuous filaments

Patent metadata

Field	Value
Publication number	US-12480237-B2
Application number	US-202318200610-A
Country	US
Kind code	B2
Filing date	May 23, 2023
Priority date	May 28, 2018
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

A spunbonded nonwovens is made by first spinning thermoplastic continuous filaments and emitting them from a spinneret in a direction and then passing the filaments in the direction through a cooling chamber. Meanwhile cooling air is fed from respective manifolds flanking the chamber into the chamber to cool the filaments and the cooling air is guided into the manifolds through respective manifolds and through respective planar homogenizing elements each having a plurality of openings forming a free open surface area constituting 1 to 40% of the total surface area of the respective planar homogenizing element. The cooling air passes from the planar homogenizing element into the cooling chamber through a flow straightener.

First claim

We claim:

1 . A method of making spunbonded nonwovens comprising the steps of:
spinning thermoplastic continuous filaments and emitting them from a spinneret in a filament direction and at a filament speed; passing the filaments in the filament direction through a cooling chamber; feeding flows of cooling air from respective manifolds oppositely flanking the chamber into the chamber to cool the filaments; setting the flows from the manifolds asymmetrically; and guiding the cooling air in the manifolds through respective planar homogenizing elements each having a plurality of openings forming a free open surface area constituting 1 to 40% of a total surface area of the respective planar homogenizing element, and then through respective flow straighteners into the cooling chamber.

2 . The method defined in claim 1 , wherein the cooling air is applied in the chamber to the filaments at an air speed of from 0.15 to 3 m/s.

3 . The method defined in claim 1 , wherein the cooling air is fed into the chamber from the manifolds to the filaments in the cooling chamber in streams at a rate of from 200 to 14000 m 3 /h/m.

4 . The method defined in claim 1 , wherein the manifolds each have a vertical height of from 400 to 1500 mm.

5 . The method defined in claim 1 , further comprising the step of:
supplying the cooling air to the manifolds as a plurality of substreams from respective conduits.

6 . The method defined in claim 1 , further comprising the steps of:
subdividing the cooling-air stream into two to five substreams.

7 . The method defined in claim 5 , further comprising the step of:
imparting to the cooling air of at least two of the substreams respective different air speeds or different temperatures or different humidities.

8 . The method defined in claim 1 , further comprising the step of:
subdividing each manifold into at least two manifold sections from which cooling air of different temperatures is supplied as two respective substreams.

9 . The method defined in claim 1 , wherein a free open surface area of each of the homogenizing elements that are provided one after the other increases in an air-flow direction toward the respective flow straightener.

10 . The method defined in claim 1 , wherein a surface area of each homogenizing element extends over at least half of a manifold cross-sectional area of the respective manifold.

11 . The method defined in claim 5 , wherein a cross-sectional area of each conduit increases stepwise in a plurality of stages or continuously in an air-flow direction to the respective manifold.

12 . The method defined in claim 5 , further comprising the step of:
homogenizing flow of the cooling air into the manifolds with predistribution elements in the conduits upstream of the manifolds.

13 . The method defined in claim 12 , wherein the predistribution elements are wedge-shaped passages, gap passages with covers, or outflow pyramids.

14 . The method defined in claim 1 , wherein the flows of the cooling air are set asymmetrically by partially screening flow through one of the manifolds.

15 . The method defined in claim 14 , wherein only the upper 100 mm of an output end of the one manifold are partially screened off.

16 . The method defined in claim 1 , wherein the flows are set asymmetrically by vertically or horizontally offsetting an outlet end of one of the manifolds relative to an outlet end of the other manifold.

17 . The method defined in claim 16 , wherein the outlet end of the one manifold is offset vertically or horizontally by at most 100 mm from the outlet end of the other manifold.

18 . The method defined in claim 1 , wherein the flows of the cooling air are set asymmetrically by varying the flows of the cooling air from at least one of the manifolds relative to the flow from an outlet end of the other manifold.

19 . The method defined in claim 1 , wherein the filaments are of polypropylene and/or polyethylene terephthalate and the filament speed is at least 2000 m/min.

20 . The method defined in claim 1 , wherein the filaments are of polyethylene terephthalate and the filament speed is at least 4000 m/min.

21 . A method of making spunbonded nonwovens comprising the steps of:
spinning thermoplastic continuous filaments and emitting them from a spinneret in a filament direction and at a filament speed; passing the filaments in the filament direction through a cooling chamber; feeding flows of cooling air from respective manifolds oppositely flanking the chamber into the chamber to cool the filaments; and setting the flows from the manifolds asymmetrically while simultaneously guiding the cooling air in the manifolds through respective planar homogenizing elements each having a plurality of openings forming a free open surface area constituting 1 to 40% of a total surface area of the respective planar homogenizing element, then through upstream flow screens on intake sides of respective flow straighteners, then through the straighteners and finally out of the straighteners through downstream flow screens on output sides of the flow straighteners into the cooling chamber.

Assignees

• Nitschke Michael
• Neuenhofer Martin
• Geus Hans Georg
• Frey Detlef
• Reifenhaeuser Masch

Inventors

• Nitschke Michael
• Neuenhofer Martin
• Geus Hans-Georg
• Frey Detlef

Classifications

• D04H3/077

  Stick, rod or solid cylinder shaped · CPC title

• D04H1/76

  otherwise than in a plane, e.g. in a tubular way · CPC title

• D01F8/04

  from synthetic polymers · CPC title

• D01D5/0985

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

• D01D5/088 Primary

  Cooling filaments, threads or the like, leaving the spinnerettes · CPC title