EP0603192B1 - Method and apparatus for producing non-woven tape from disordered fibres - Google Patents

Abstract

Described is a method of producing non-woven tape (10), in which the disordered fibrous material (3) in a stock bin (2) is fed by a pair of feed rollers (4, 5) on to a needle board (6). Combs (7, i) on the needle board (6) pull the fibrous material (3) with them, thus forming a non-woven tape (10). The needle board (6) transfers the tape (10) thus produced to an opening cylinder (8) which further improves the opening of the non-woven tape (10). Production of the non-woven tape in this way protects the fibres better than prior art methods and produces only insignificant changes in the fibre length in particular.

Description

The invention relates to a method for producing uniform nonwoven tapes and an apparatus for performing the method.

There are numerous methods and devices for the qualitative and quantitative testing of textile fibers. In many test methods, the disordered fiber material, e.g. Cotton in flake form, should not be measured immediately, but must first be processed in nonwoven tapes with a parallel fiber layer. These tapes are then used as a sample for obtaining quality measurements on the fiber material and, in the form of continuous non-woven tapes, as a preliminary stage in the production of threads or yarns from the fiber material.

Known devices for dissolving fiber flakes usually consist of a pair of feed rollers and a pulping drum. A subsequent drum takes over the dissolved material, stores it or transports it further. The A pair of feed rollers ensures the controlled material handling, which is essential in view of the high degree of opening required for the fiber flakes. In such pulping devices for fiber flakes, there is a need to produce the desired sliver as far as possible without damaging the fiber. Devices of this type according to the prior art, for example cards, have a high throughput, but the fibers are damaged to a considerable extent. In the case of cards according to the prior art, it is also known to structure the feed rollers, for example by attaching spirals to the surface of the feed rollers or a clothing with hook-like elements arranged in the running direction. The main purpose of these structures is to prevent the fibers from sticking to the rollers. A selective retention of the fibers is not possible with these structures, which leads to increased fiber damage to the fiber samples obtained with them.

When disordered fiber material is fed by means of a pair of feed rollers to an opening roller provided with a "card clothing", the opening roller is released and a uniform nonwoven fabric is obtained therefrom. The pair of feed rollers preferably moves at a lower peripheral speed than the opening roller. At least one feed roller can also be provided with a "card clothing", the elements of this "clothing" running counter to the direction of rotation of the food roller. The pair of feed rollers selectively hold the still disordered fiber material in line, while the "Card clothing" of the opening roller continuously grips and dissolves part of the fibers. A fiber fleece is then made on the subsequent doubling roller.

In textile technology, the "card clothing" of a roller is understood to mean the application of a series of narrow strips on the lateral surface of the roller, which are usually covered with teeth or hooks, either in the direction of rotation or inclined against them. Likewise, a corresponding design of the outer surface of the roller itself, which can be created, for example, by engraving or rolling and with which teeth or hooks are attached to the outer surface of the roller, can be referred to as a clothing. For the sake of brevity, such teeth and ticks are summarized below under the term "tick".

In the method mentioned, the individual fibers of the disordered fiber material are only retained on one line. If the opening roller pulls on a longer fiber, the remaining fibers behind the retention line are drawn towards the feed rollers. As a result, there is always an excess of fiber material between the feed rollers, whereby the selective effect of the clothing on one of the two feed rollers is reduced more and more. Finally, the fiber material is clamped again. If a fiber is now caught by the release roller, the retention force is so great that the fiber is torn off.

The resulting nonwoven web therefore no longer has the quality characteristics of the disordered fiber material and can therefore no longer be regarded as a fully representative sample. The torn pieces of the long fibers also reduce the quality of the yarn if the nonwoven web is used as a preliminary stage for yarn production.

From EP-B1 0 247 420 a device for end-arranging fibers for a fiber length measurement is also known, in which a nonwoven fabric is inserted into a needle transport device consisting of a plurality of needle combs and is cyclically transported by this to a pliers device with which the nonwoven fabric is used a sample can be taken. The needle transport device in this known device consists of a "needle bed". This term is to be understood as a series of parallel combs with needles that can be moved transversely to the comb direction. During the resting cycle of the nonwoven, the foremost comb of the needle bed in the direction of transport is moved into the last position of a lower row of combs with the transport direction reversed. The comb of this lower row of combs, which is in the foremost position, is simultaneously retracted into the needle bed as the rearmost comb. During transport, the needle bed has no significant influence on the alignment of the fibers in the nonwoven. The needle bed is only used to hold the fleece in place during the extraction of a partial sample to determine the fiber length distribution.

There are other needle transport systems from N.Schlumberger & Cie. That are already on the market. NPC known, e.g. under the designation "Intersecting range GN 6" (company brochure Intersecting range GN6, pages 8/9, and company brochure GN6, page 5) or "Chain range GC13" (company brochure page 5), in which instead of a pair of pliers (as with EP-B1 0 247 420) a pair of rollers is mounted and with which slivers or nonwovens can be combed, de-felted and doubled. However, these known needle transport systems or needle drawing systems are not suitable for dissolving disordered fiber material.

From FR-A-2086325 a method for producing a nonwoven is known, in which a nonwoven with disordered or ordered fibers in a certain other way can be produced from a fiber composite with aligned fibers. The process requires several rollers that are filled with needles. The desired disorder or reordering of the fibers is done here by multiple transfer of the fibers from one roller to the other. At the end, the fleece is removed from the needle tips of the last roller by a comb. In this method, the needles are each fed and removed by a swiveling movement to the nonwoven fiber band, the piercing movement of the needle tips carried out being combined with a translational movement. With such a plunge movement, it is very likely that fibers will be injured. In addition, this process is based on dissolved and ordered fibers, not on disordered fibers.

The invention has for its object to provide a method with which a uniform nonwoven web can be produced from disordered and undissolved fiber material better than with the known methods with the greatest possible protection of the fiber quality, in particular the fiber length distribution.

The invention achieves the stated object with a method which has the features of claim 1 and a device which has the features of claim 13.

Further advantageous embodiments of the invention are characterized in the dependent claims.

• Fig. 1 stellt eine schematische Darstellung einer Vorrichtung zur Durchführung des erfindungsgemässen Verfahrens dar;
• Fig. 2 stellt eine schematische Darstellung einer modifizierten Vorrichtung zur Durchführung des erfindungsgemässen Verfahrens dar;
• Fig. 3 stellt einen partiellen Schnitt durch ein Nadelstreckwerk nach dem Stand der Technik dar; und
• Fig. 4 stellt einen zur Fig. 3 analogen partiellen Schnitt durch eine erfindungsgemässe Vorrichtung dar.

Two embodiments of the invention, which also explain the principle of operation, are shown in the drawings and are described in more detail below.

• Fig. 1 shows a schematic representation of an apparatus for performing the method according to the invention;
• 2 shows a schematic representation of a modified device for carrying out the method according to the invention;
• Fig. 3 shows a partial section through a needle drafting system according to the prior art; and
• FIG. 4 shows a partial section analogous to FIG. 3 through a device according to the invention.

The device 1 shown in Fig. 1 consists of an open storage container 2, in which unordered fiber material 3 is located, a pair of feed rollers 4, 5 with a first feed roller 4 and a second feed roller 5, a needle bed 6 with an upper row 11 of combs and a lower row of combs 12, which consists of individual combs 7, i with needles, which engage in a non-resolved nonwoven web 10 to be produced by the device and which move with a transport device, not shown, from the feed roller pair 4, 5 towards the opening roller 8 . Further details of the needle bed 6, in particular about their transport device, are described in EP-B1 0 247 420 and, moreover, from the above-mentioned devices on the market, for example from the company N. Schlumberger & Cie. known.

The opening roller 8 is followed by a drum 9, preferably in the form of a doubling roller, on which the dissolved fibers are doubled, which ultimately results in the dissolved nonwoven web 10.

Since the peripheral speed of the opening roller 8 is much greater than the transport speed of the needle bed 6, the fibers captured by the opening roller 8 are immediately pulled out of the nonwoven fabric and transported as a single fiber onto the spool 9, from which a uniform, dissolved nonwoven web 10 is produced. Through this pull-out process, the tufts of different densities are dissolved.

The disordered and undissolved fiber material 3 lying in the storage container 2 is continuously detected and discharged by the feed roller pair 4, 5 in small quantities against this supply. The nonwoven web 10 is pre-formed between the feed rollers 4, 5 runs with the combs 7, i of the needle bed 6 to the opening roller 8 and further to the drum 9 (preferably in the form of a doubling roller), with the transition of the disordered fiber material with each transition 3 is perfected into a nonwoven web 10 made of dissolved fibers.

The needle bed 6 runs slightly faster than the peripheral speed of the feed rollers 4.5, so that no windings can occur between the feed rollers 4.5. The pair of feed rollers 4, 5 carries the amounts of the fiber material 3 to be drawn off to the needle bed 6, which consists of combs 7, i which can be moved individually in the direction of the nonwoven web 10 and are filled with needles. The needles of the combs 7, i take the fiber material 3 with them. Through this process, the fiber material 3 is converted into a nonwoven web 10. In the textile industry, "dissolution" is understood to mean the increase in the orderly state of a fiber structure, fibers which are severely entangled being pulled apart or "separated". This dissolution takes place at the transition of the nonwoven web 10 to the opening roller 8.

The transport device of the needle bed 6, not shown, additionally causes the following movements: In each case the comb 7 which faces the feed rollers 4, 5 n the upper row of combs 11 is in the course of the transport movement into the comb position 7,1 which faces the feed rollers 4,5 Needle bed 6 transferred. At the same time, the comb 7, n / 2 of the needle bed 6 facing the opening roller 8 is transferred into the comb position 7, n / 2 + 1 of the top row 11 assigned to the opening roller 8. Thus, the combs 7, i are continuously exchanged cyclically by the transport device and moved along the needle bed 6. The movement of the transport device can be done continuously or intermittently. The needle bed 6 must expediently be longer than the largest fiber length that occurs.

On the side of the needle bed 6, on which the nonwoven web 10 runs, there is an imprinter 12 which moves back and forth on the needle bed 6, reaching between the combs 7, i, and the nonwoven web 10 repeatedly in the needle bed 6 pushes back. In contrast to the "needle drawing frames" according to the prior art, it is therefore possible to work with a single-sided needle bed.

As shown in FIG. 2, the needle bed 6 can also be realized in the form of a pair of needle bands 16. The two needle belts 16 equipped with needles 17 each run on two pairs of drive cylinders 22. The drive cylinders 22 (not shown in the drawing) can be driven by an electric motor and can be controlled together with the other elements of the device 1. The two needle ribbons 16 are arranged parallel to one another in such a way that their needles 17 engage one another and can thereby take the fiber material 3 with them. For this purpose, the respective pairs of drive cylinders 22 of the two needle belts 16 are to be moved in opposite directions, so that the adjacent parts of the two needle belts 16 move in the same direction in the direction of the opening roller 8.

The remaining elements of this modified device have already been described in connection with FIG. 1. The advantage of this modified version is that the mechanics are less complex and therefore cheaper.

1 or 2, a limiter 13 is expediently installed between the opening roller 8 and the needle transport device 6; 16, which prevents the fibers from being lifted vertically out of the needles 7; 17 by the opening roller 8, which results in a reduction retention force and deterioration in resolution.
A hold-down 14 is expediently attached to a lever 15 between the opening roller 8 and the drum 9 (preferably in the form of a doubling roller). In the case of multi-layer nonwoven tape application on the drum 9, this hold-down device 14 ensures that the fiber or nonwoven tape portions previously applied to it are held down before, for example, a new nonwoven tape portion is added.

At least one of the feed rollers 4, 5 can have knobs, that is to say wart-like elevations on their lateral surfaces, or a set with hooks opposite to their running direction in order to produce a better fiber feed.

The opening roller 8 is expediently equipped with a set, the hooks of which are in the running direction of the opening roller 8. The drum 9, which is preferably in the form of a doubling roll, should also be equipped with a set with hooks in the running direction in order to be able to take over the dissolved fibers on the opening roller 8. The peripheral speed of the spool 9 must be greater than that of the opening roller 8.

The changes in the fiber length distribution are minimal in the method according to the invention. The fibers are dissolved according to the invention between the needle transport device 6; 16 and the opening roller 8. The needle transport device 6; 16 generates the retaining force and the opening roller 8 generates the pull-out force. These two forces must be optimally coordinated; if both forces are too great, the fiber will be torn; if both forces are too small, the achievable resolution is poor. The advantage of the method according to the invention is that the retention force is selective and extensive. In this context, selective means that each fiber is held back individually by a few needles, depending on its length. In the usual clamping methods according to the prior art, the fibers are clamped on a line, which leads to an excessively high retention force and thus to fiber damage. With retention on a line, the fibers behind the retention line are increasingly compressed, which leads to an increase in retention force and damage to the fibers.

3 and 4, the problem of the fiber hook is shown. In the methods according to the prior art, as shown in FIG. 3, the situation can arise that the needle tip 21 of the needle comb 7 is enclosed by a fiber 20 forming a closed loop. If, as in the prior art, the take-off device consists of a pair of rollers 18, 19 which clamps the fibers in a line and pulls them out of the fiber material in this way, the fiber 20 is forcibly destroyed.
As shown in FIG. 4, this problem is solved in the method according to the invention by using an opening roller 8 with sets. The fiber 20 forming a check mark is only taken over by the release roller 8 when the retaining needle has been removed. The pull-off forces are therefore also selective, in contrast to the clamping line in the "needle drafting system" according to the prior art (FIG. 3). The fiber length distribution is thus better preserved in the method according to the invention than in the previously known methods.

The method according to the invention thus achieves the task of producing a uniform nonwoven web 10 from disordered fiber material 3 better than the methods which have become known, while protecting the fiber quality as much as possible, in particular the fiber length distribution.

Claims (23)

1. Method for producing uniform nonwoven webs (10) from a supply of unordered fibre material (3), in which the unordered fibre material (3) is fed to an opening roller (8), the fibre material (3) assuming the form of a nonwoven web (10), characterized in that

   A) the quantities of fibre material (3) to be drawn off are discharged onto a needle-type transport system (6;16) having needles (21;17) movable in the direction of the nonwoven web (10) to be formed,

   B) the needles (21;17) take up the fibre material (3),

   C) the fibre material (3) is transported in the needle-type transport system (6;16) as far as the end of the latter and is then discharged onto the opening roller (8),

   D) the discharged fibre material (3) is separated on the opening roller (8), and

   E) the fibre material (3) separated on the opening roller (8) is transferred in the form of a nonwoven web (10) onto a cylinder (9).
2. Method according to Claim 1, characterized in that the fibre material (3) is discharged by means of a pair of feed rollers (4,5).
3. Method according to Claim 1 or 2, characterized in that the needle-type transport system (6;16) takes the form of a needle bed (6) which consists of combs (7,i) which are movable individually in the direction of the nonwoven web (10) to be formed and which are equipped with needles (21).
4. Method according to Claim 3, characterized in that the combs (7,i) arranged in the needle bed (6) in series in the direction of the transport path are moved by a transport device.
5. Method according to Claim 4, characterized in that the transport device transfers the particular comb (7,n/2) closest to the opening roller (8) in the needle bed (6) into the comb position (7,n/2+1) closest to the opening roller (8) in an upper comb series (11) and the comb (7,n) closest to the feed rollers (4,5) in the upper comb series (11) into the comb position (7,1) closest to the feed rollers (4,5) in the needle bed (6), thereby bringing about a continuous cyclic exchange of the combs (7,i) and a movement of the combs (7,i) in the needle bed (6) from the feed rollers (4,5) to the opening roller (8) and of those of the upper comb series (11) from the opening roller (8) to the feed rollers (4,5).
6. Method according to Claim 4 or 5, characterized in that transport takes place continuously.
7. Method according to Claim 4 or 5, characterized in that transport takes place intermittently.
8. Method according to one of Claims 3 to 7, characterized in that the nonwoven web (10) is retained in the needle bed (6) by a pressing-in device (12) passing through between the combs (7,i).
9. Method according to Claim 8, characterized in that the pressing-in device (12) is moved by the transport device.
10. Method according to Claim 1, characterized in that the needle-type transport system takes the form of two needle bands (16) which are arranged parallel to one another, are movable by means of drive cylinders (22) and which are equipped with needles (17) which can engage in one another along the parts of the two needle bands (16) bearing on one another and which can thereby move the fibre material (3) along with them.
11. Method according to one of Claims 2 to 10, characterized in that the circumferential speed of the feed rollers (4,5) is lower than the speed of the needles (21;17) of the needle-type transport system (6;16).
12. Method according to one of Claims 3 to 11, characterized in that the speed of the needles (21;17) of the needle-type transport system (6;16) is lower than the circumferential speed of the opening roller (8).
13. Apparatus for carrying out the method according to one of Claims 1 to 12, characterized in that it consists at least of a needle-type transport system (6;16), of an opening roller (8) and of a cylinder (9).
14. Apparatus according to Claim 13, characterized in that it comprises two feed rollers (4,5).
15. Apparatus according to Claim 13 or 14, characterized in that the needle-type transport system comprises a needle bed (6) with combs (7,i), a pressing-in device (12) and an upper comb series (11).
16. Apparatus according to Claim 13 or 14, characterized in that the needle-type transport system takes the form of two needle bands (16) which are arranged parallel to one another, are movable by means of drive cylinders (22) and which are equipped with needles (17) which engage in one another along the parts of the two needle bands (16) bearing on one another.
17. Apparatus according to one of Claims 14 to 16, characterized in that at least one of the feed rollers (4,5) has a clothing with small hooks counter to the direction of run of the feed roller (4,5).
18. Apparatus according to one of Claims 13 to 17, characterized in that the outer surface of at least one feed roller (4,5) has knobs.
19. Apparatus according to one of Claims 13 to 18, characterized in that the outer surface of the opening roller (8) has a clothing with small hooks in the direction of run of the opening roller (8).
20. Apparatus according to one of Claims 13 to 19, characterized in that the cylinder (9) takes the form of a folding roller, the outer surface of which has a clothing with small hooks in the direction of run of the cylinder (9).
21. Apparatus according to one of Claims 13 to 20, characterized in that a holding-down device (14) is mounted on a lever (15) on the folding roller (9).
22. Apparatus according to one of Claims 13 to 21, characterized in that the length of the needle bed (6) is longer than the greatest fibre length occurring.
23. Apparatus according to one of Claims 13 to 22, characterized in that a limiter (13) for retaining the fibres within the needle-type transport system (6;16) is provided between the opening roller (8) and the needle-type transport system (6;16).

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