WO2009112008A1

WO2009112008A1 - Method and device for presolidifying a non-woven

Info

Publication number: WO2009112008A1
Application number: PCT/DE2009/000283
Authority: WO
Inventors: Ullrich MÜNSTERMANN
Original assignee: Fleissner Gmbh
Priority date: 2008-03-12
Filing date: 2009-02-26
Publication date: 2009-09-17
Also published as: WO2009112015A1

Abstract

The invention relates to a method and to a device for presolidfying a non-woven fabric from fibres and/or filaments. Said non-woven fabric is transported on an underlay using a device for water jet needling. According to the invention, the device (3) for water jet needling is positioned at a large distance from the underlay (2) supporting the non-woven fabric. Preferably, water jet needling takes place on a perforated belt acting as the perforation, comprising perforation structures and/or perforation bodies. Also, a binding agent is introduced into the presolidifed non-woven (V) and is activated by an oven (13) such that the interlacing of the fibres and/or filaments, produced by water jet, are fixed.

Description

Method and device for preconsolidating a nonwoven

The invention relates to a method and a device for the preconsolidation of a nonwoven according to the preamble of the method and the device claim.

A pile produced by means of a carding machine or a spunbonded installation must be preconsolidated depending on the type of further processing. This is especially the case when the pile is to be treated by means of a pad with a foam or a liquid. Known methods of preconsolidating a pile are based on water-jet needling, in which the pile lying on a conveyor belt is compressed under another endless belt (compacting belt) and processed through these belts by one or more water-jet recycling devices (water beam - DE 102 05 151) becomes. Other possibilities of preconsolidation are calendering or thermally hot-air bonding methods. However, this requires component costs. A pile consisting of finely long fibers and / or infinitely long filaments can also be driven directly, ie without preconsolidation by a padder, but in order not to destroy the pile, only very low processing speeds can be achieved.

A production process for a nonwoven fabric is known in which a fleece (pile) provided by a pile producer (eg carding machine) is passed through a foam pad in the form of a material web. In the foam, a binder is dissolved, which is introduced into the pre-fleece. After the padder, the binder is activated in the pre-fleece - to the material web is passed through a hot air dryer or an oven. Object of the present invention is to improve a method and an apparatus for performing the method according to the preamble of the method or device claim.

This object is achieved by the features of the method or device claim. Advantageous developments of the invention will become apparent from the respective dependent claims.

As a method or as the method performing device, the following measures are provided:

- For pre-consolidation of a pile of fibers and / or filaments of the pile is transported on a base and thereby subjected to water jet needling. The device for water jet netting is positioned at a great distance from the pad supporting the web.

- The distance is greater than the distance that is chosen in a water-jet solidification, in particular more than twice the value.

- The distance is between 15 - 100 mm.

- A distance is chosen so that through the water jets in connection with the below

Extraction generated air flow substantially perpendicular to the direction of movement of the pile penetrates and through the pile.

- A pile with a basis weight of less than 100 g / m ^{2 is} processed.

- The processing speed is more than 100 m / min. - The water pressure of the waterjet needling is less than 100 bar.

- The pile is placed on a perforation serving pad, preferably a band serving the perforation, a screen belt and subjected to water jet needling.

A binder is introduced into the preconsolidated nonwoven by impregnating the nonwoven with a fluid containing the binder.

- The pre-consolidated fleece is passed through a foam padder.

The nonwoven has, after preconsolidation, a specific tensile strength F _s pez less than or equal to 0.08 [N / 50mm] / [g / m ² ], the specific tensile strength being defined as the tensile strength in N / 50mm divided by the nonwoven weight in g / m ² .

- The nonwoven has a density less than or equal to 0.05 g / cm ³ after preconsolidation.

The preconsolidated nonwoven is further processed into a nonwoven fabric using the steps:

Introducing a binder into the preconsolidated nonwoven,

Activating the binder so that the entanglements of the fibers and / or filaments produced by the application of water jet are fixed.

- The apparatus for carrying out the method consists of a generator for a consisting of fibers and / or filaments pile, which is placed on a movable relative to a device for Wasserstrahlbeaufschlagung pad, and one of the means for Wasserstrahlbeaufschlagung assigned and on the opposite side of the Pile supporting pad Neten exhaustion. The device for water jet needling is positioned at a great distance from the pad supporting the pile.

- The device for water jet needling is a device for dyeing, impregnating downstream in particular in the form of a padder.

- The pad supporting the pile is designed as a sieve band.

- The pad supporting the pile has the perforation serving structures, body and is preferably a perforation serving band.

The pad supporting the web is a screen belt with perforation structures or perforation bodies located thereon.

- The perforation bodies are made of a plastic.

The means for activating the binder is designed as a furnace.

According to the invention, it is provided that the device for water jet needling be positioned at a large distance from the pad supporting the pile. The pad supporting the pile is preferably an endlessly circulating wire. In principle, however, it is also possible to transfer the unconsolidated pile to a sieve drum and then to carry out the needling according to the invention at a large distance from the device for water jet needling.

The distance of the device for water jet needling to the pile-supporting pad is greater than in a conventional Wasserstrahlvemadelung, ie greater than 15mm. Preferably, the Distance between 25 and 100 mm - more preferably a value between 30 and 80 mm is selected. In this case, the distance according to the present invention is understood to mean the free path of a water jet between the outlet of the water bar and the pad supporting the nap.

According to the invention, such a distance from the water beam to the pad supporting the web is essential so that, due to the water jets emerging at the underside of the water beam, a drag flow results, which is essentially vertical in relation to the suction located below the base and penetrates through the pile.

It is preferably provided that a pile with a weight per unit area of less than 100 g / m ^{2 is} processed. In this case, according to a preferred embodiment of the invention, a processing speed of more than 100 m / min driven.

It is advantageous that the water pressure of the water jet needling is less than 100 bar. The height of the water pressure depends here preferably on the fiber or filament thickness, the titer. For example, a water pressure of 20 - 40 bar is set at 1.7 dtex. For fibers / filaments of 6 dtex, the water pressure to be set is preferably 40-80 bar. The lower pressure value shall be used for weights per unit area up to approx. 30 g / m ² , the upper pressure value shall apply to fiber or filament webs where the basis weight is up to 100 g / m ² .

According to a further preferred embodiment of the invention, the water jet needling of the unconsolidated pile takes place on a perforated screen belt (perforation screen belt). The preferably used screen belt has a mesh thickness of 25- 50 wires per cm (weft and warp wires). The permeable degree of sifting (proportion of open area) is less than 20%, preferably less than 15%. The perforation serving body on the Sieboberfläche consist of a plastic material and preferably have a convex shape in the manner of water droplets. Such a screen material with perforation bodies is known from US 5,115,544 and therefore need not be described in detail. It is relevant in connection with the present invention that, on the one hand, and the use of a perforating screen belt explained in more detail above, a web can be pre-consolidated and perforated simultaneously without any preconsolidation, in order to subsequently apply it preferably for further processing Foulard feed.

According to the invention, it is provided as a further manufacturing method that the fleece provided by a pile producer - consisting of fibers and / or filaments - is subjected to water jet application for preconsolidation. Subsequently, the thus pre-bonded web is provided with a preferably thermally activable binder. The activation of the binder is then carried out in a conventional manner by means of an oven or a dryer.

It is essential here that the entanglement of the fibers and / or filaments of the pre-fleece caused by the application of water jet is not too strong and, subsequently, a fixation of these entanglements by the binder or its activation takes place.

Too much preconsolidation creates a very closed nonwoven structure into which the binder dissolved in a foam or a liquid can not penetrate optimally. Also, after activating the binder, the properties of the nonwoven (the final Ducts) predominantly by the entanglement of the fibers, the filaments determined.

Too little preconsolidation of the pre-fleece by the water-jet impingement limits the possible processing speed of the pre-fleece and thus the production speed, since otherwise the weak fleece structure would be destroyed during the introduction of the binder. Ultimately, the properties of the nonwoven fabric (end product) are determined predominantly by binder bonding if the precursor is not sufficiently consolidated by the binder introduced and its activation. The corresponding nonwoven fabric becomes stiff.

As a device according to the invention a device for Wasserstrahlbeaufschlagung provided by means of the material web (the pile) is pre-consolidated. The at least one water bar, with which the water jet is applied for preconsolidation, is positioned at a great distance from the substrate carrying the material web, in particular more than 15 mm. Preferably, the distance between 25 and 100 mm - preferably a value between 30 and 80 mm is selected.

It is preferably provided that the nonwoven fabric has a specific tensile strength F _spe z of less than or equal to 0.08 [N / 50 mm] / [g / m ² ] after the preconsolidation and before the introduction of the binder through the padder, the specific tensile strength being defined is the tensile strength in N with respect to a 50 mm wide strip divided by the web weight in g / m ² . The density of the nonwoven is preferably less than or equal to 0.05 g / cm ³ .

The invention is preferably embodied when the device for water jet needling is followed by a device for removing moisture from the pre-bonded nonwoven. It can be provided that the device for removing moisture the pre-consolidated web is formed as a suction. The apparatus for removing moisture from the preconsolidated nonwoven fabric may be formed as a dryer or as a nip roll acting on the nonwoven. By dewatering and / or drying of the pre-consolidated web before the introduction of binder, the capacity for the binder and the distribution can be influenced. Thus, the nature and extent of dewatering and / or drying of the preconsolidated web before it passes through the foam pad (the application station for the binder) may affect the properties of the final product in a wide range.

The oven for activating the binder may be formed as a drying device which guides the material web of the nonwoven around one or more drums. It is also possible to guide the web through a belt furnace - the web is here preferably supported by a sieve pad. The thermal energy input is made by hot air or radiant heater (infrared). Ultimately, the nature of the binder is critical to the type of furnace to be used.

Furthermore, the explanation of an embodiment with reference to the drawings.

According to FIG. 1, a pre-fleece is provided as a pile F of fibers and / or filaments by means of a pile fabricator 1 (carding machine, spin-layer) and deposited on a belt 2 designed as a sieve and circulating endlessly around rolls. The still unsolidified pile F is conveyed through a solidification station, consisting of a water bar 3 with a plurality of water outlet nozzles and located on the underside of the belt 2 suction 4. The solidification station 3, 4 is downstream of a further suction 5 in the conveying direction of the web V. This suction serves to remove the excess water in the fleece V. The nonwoven fabric V pre-consolidated by the solidification station 3, 4 is fed to a padder having two pinch rolls 6, 7. The fleece V is passed through the waist 6, 7, which are pressed against each other with pressure. Above the contact of the two rollers 6, 7 is a foam supply, which is provided by a foam supply 8 and maintained at a predetermined stock value. In the foam, a thermal energy (heat) activatable binder is dissolved. This binder thus enters the volume of the web V.

A roller 6 of the padder has an engraving, the other roller has a smooth surface. This ensures that the fleece V conveyed through the nip and impregnated with foam (the binder) remains in contact with the roller 7 and can thus be conveyed further in the intended direction to the oven 13 downstream of the foam padder 6, 7, 8. In this takes place by heat input, the activation of the binder (hardening).

Figure 2 shows the arrangement of water bar 3 and suction 4 in detail. The water bar 3 is set according to the invention in such a manner relative to the resting on the belt 2 Flor F, so that the distance a of the bottom to the pile top is about 15 to 80 mm. This corresponds to a distance greater than the distance when the water bar 3 is used for conventional hydroentangling.

On the other hand, the distance a at which the water beam 3 is adjusted with respect to the pile F located on the belt 2 can be defined as a ratio to the width b of the underside of the water beam 3. Accordingly, the distance a should be at least half the width b of the water bar underside. Here it is assumed that as the width b of the water bar 3 of the substantially parallel to the level of the belt 2 extending part of the underside of the water bar 3 is to be evaluated.

As indicated in FIG. 2, the water jets 9 of the water bar 3, on the one hand, and due to the air friction on the one hand and the exhaust 4 located below the belt 2 on the other, produce a flow which is indicated by the arrows. It is essential here that the flow in the area of the upper side of the pile F runs essentially vertically into and through the pile F. This results in no flow components in the direction of Flores F, which could lead to disturbances in the structure of Flores F.

The flow situation indicated in FIG. 2 results from the selected distance a of the water bar 3 in relation to the width b of the water bar 3. It would be apparent that the air flow through a water bar 3 positioned at a smaller distance a relative to the belt 2 and the suction 4 would be flatter, then that flow components parallel to the plane of the belt 2, the Flors F result.

The embodiment of Figure 3 additionally shows a dryer 10, the water bar 3 nach- in the conveying path of the web V and the padding 6, 7, 8 upstream. The dryer 10, which is indicated in principle in FIG. 3, can be a drying device operating with radiation and / or flowing air.

According to FIG. 4, it is also possible to provide a nip roller 11 which cooperates with the nonwoven and cooperates with a counter-roller 12. This roller pair 11, 12 serves to remove excess water from the nonwoven V and is downstream of the water bar 3 in the conveying path of the nonwoven V and precedes the padder 6, 7, 8.

FIG. 5 shows an embodiment of the invention in which the water Beam exposure of the pile F for pre-consolidation takes place on a first band 2.1. The screening fineness of the band 2.1 designed as a sieve is adapted to the water jet application in an optimized way. Thereafter, the preconsolidated nonwoven V is transferred to a second belt 2.2, which is likewise designed as a sieve. Here, too, the dewatering of the web V by means of the suction takes place 5. Accordingly, the screening fineness is chosen so that there is the desired degree of drainage.

Instead of a first band 2.1 may also be provided a water-permeable drum, which cooperates with a water bar. Inside the drum, a suction is arranged in a conventional manner. Again, the fineness of the drum surface is adapted to the pre-consolidation by means of water jets. The inventive distance of the water bar to the surface of the drum (length of the water jets) corresponds to the distance Wasserbalken - band of the other embodiments.

After Vorverfestigung the pile on the drum, the fleece is transferred to a belt and dewatered there by suction and optionally dried and / or treated by rollers.

FIG. 6 shows a section through a belt 2 designed as a perforated screen belt, with which in a processing step a web F can be consolidated and perforated, in order subsequently to supply it to a padder for application with a binder.

On a designed as a sieve Volume 2 existing perforation structures or perforation body PK are made of transparent plastic. These have a convex surface shape in the manner of a water droplet. Through the water jet 9, the pile F is solidified and at the same time its fibers (and / or filaments) are distributed around the perforation bodies PK, so that after the water jet Needling (after the water jet 9) a perforated fleece PV is present.

The preferably used screen belt has a mesh size of about 30 wires per cm (average weft and warp wires). The permeability of the screen mesh (proportion of open area) is less than 15%.

FIG. 6 shows a detail of the surface of the perforation screen belt with the belt 2 formed as a screen and the transparent perforation bodies PK situated thereon.

LIST OF REFERENCE NUMBERS

I pile producer (carding, spunbond, meltblown) 2 band (endless belt, sieve, sieve belt, perforation screen belt)

3 water bars

4 suction

5 suction

6 roller (foulard) 7 roller (foulard)

8 foam supply

9 water jet

10 dryers

I 1 squeegee 12 counter roller

13 oven

2.1 first volume (endless belt, sieve)

2.2 second volume (endless belt, sieve) F Flor

V fleece (pile hardened)

PV fleece perforated

PK perforation body

a distance (water bar - pile) b width (bottom water bar)

Claims

claims

A method of preconsolidating a pile of fibers and / or filaments, wherein the pile is transported on a base, using a water jet needling device, characterized by, the water jet needling device (3) being at a large distance (a) from Positioning the pile (F) supporting pad (2).

2. The method according to claim 1, characterized by, the distance (a) is greater than the distance which is selected in a water-jet solidification, in particular more than twice the value.

3. The method according to claim 1 or 2, characterized by, the distance (a) is between 15 - 100 mm.

4. The method of claim 1, 2 or 3, characterized by, it is selected a distance (a), so that by the water jets (9) in connection with the below the base (2) located suction (4) generated air flow essentially perpendicular to the direction of movement of the pile (F) into and through the pile (F).

5. The method according to any one of the preceding claims, characterized by, it is a pile (F) with a basis weight less than 100 g / m ² processed.

6. The method according to any one of the preceding claims, characterized by, the processing speed is more than 100 m / min.

7. The method according to any one of the preceding claims, characterized by, the water pressure of the water jet needling is less than 100 bar.

8. The method according to any one of the preceding claims, characterized by, the pile (F) is placed on a perforation serving pad, preferably a band serving the perforation and subjected to the water jet needling.

9. The method according to any one of the preceding claims, characterized in, in the preconsolidated nonwoven (V), a binder is introduced by impregnating the nonwoven fabric (V) with a fluid containing the binder.

10. The method according to any one of the preceding claims, characterized by, the preconsolidated nonwoven (V) is passed through a foam padder (6, 7, 8).

11. The method according to any one of the preceding claims, characterized in that the nonwoven (V) after the preconsolidation, a specific tensile strength F _S p _e z less than or equal to 0.08 [N / 50mm] / [g / m ² ], wherein the specific Tensile strength is defined as the tensile strength in N / 50mm divided by the web weight in g / m ² .

12. The method according to any one of the preceding claims, characterized in that the fleece (V) after the preconsolidation has a density less than or equal to 0.05 g / cm ³ .

13. The method according to any one of the preceding claims, characterized by, the preconsolidated nonwoven fabric (V) is further processed into a nonwoven fabric, using the steps:

Introducing a binder into the preconsolidated nonwoven (V),

Activating the binding agent so that the entanglements of the fibers and / or fi laments produced by the application of the water jet are fixed.

14. A device for carrying out the method according to claim 1, consisting of a generator for a consisting of fibers and / or filaments pile, which is placed on a movable relative to a device for Wasserstrahlbeaufschlagung pad, and one of the means for Wasserstrahlbeaufschlagung assigned and at the opposite side of the pad supporting the pile, characterized by, the means for water jet needling (3) is positioned at a great distance from the pad (2) supporting the nap (F).

15. The device according to claim 14, characterized by, the device for water jet needling (3) is a device for dyeing, impregnating in particular in the form of a padder ordered.

16. The apparatus of claim 14 or 15, characterized by, the Flor (F) supporting pad is designed as a sieve belt (2).

17. The apparatus according to claim 16, characterized by, the pad (F) supporting pad is a perforation serving band (2).

18. The device according to claim 17, characterized by, the pad supporting the pile (F) is a screen belt (2) with perforation structures or perforation bodies (PK) located thereon.

19. The apparatus according to claim 18, characterized by, the perforation body (PK) consist of a plastic.

20. Device according to one of claims 9 - 15, characterized by, the means (13) for activating the binder is formed as a furnace.