DE102015207732B4 - Extrusion tool for wetting fibers - Google Patents

Abstract

Extrusion tool for wetting fibers, comprising a fiber inlet and a liquid supply unit, characterized by a flexing unit, which is designed in such a way that it has flexing areas which are designed as a wavy guide in a block and in which by movement and / or pressure mechanical pressing of a coating liquid in the form of a plastic melt into fiber interspaces.

Description

The invention relates to an extrusion tool for wetting fibers, in particular with plastics.

With the increasing demand for fiber composites as a replacement for metals or for the optimization of structures, it is becoming increasingly important to make the manufacture of fiber composites cheaper, faster and of higher quality. In particular, the wetting of the fibers with a matrix material is a problem when the fibers are embedded in this matrix.

Wetting processes common today are produced under pressure and temperature in batch processes. These are very time consuming and are mostly carried out manually.

The DE 690 14 981 T2 discloses a method and apparatus for making fiber reinforced material using thermoplastic resins. To lower the viscosity of the resin, the molten or liquid resin is subjected to shear forces.

The DE 689 02 483 T2 discloses an apparatus for impregnating plastic melts. This device comprises an extrusion press with a nozzle as an extrusion tool. The nozzle is followed by a flexing device consisting of several individual components in the form of pressure rollers.

The DE 10 2011 005 462 B3 discloses a device with which plastic melts are impregnated.

The DE 33 44 990 C2 discloses a device for impregnating fiber strands for the winding of components made of fiber-reinforced plastic.

The DE 694 09 540 T2 discloses a process for the production of flexible, dense film consisting of a textile support coated on both sides with polypropylene. As an apparatus for producing this film, an outlet of an extruder is mentioned, on which a calender is arranged as close as possible.

The EP 2 430 081 B1 discloses a fiber substrate and a method of making the fiber substrate. The fiber substrate is impregnated with an organic polymer and the impregnated fiber substrate is heated.

The KR 1020020077044 A discloses a method and apparatus for making an impregnated fiber.

Disadvantages of the prior art are the comparatively high costs, the discontinuous production and generally the optimization of the quality of the wetting.

The object of the present invention was to overcome the disadvantages of the prior art and to provide an apparatus and a method by means of which a user is able to carry out an inexpensive, continuous production of coated fibers.

This object is achieved by a device according to the claims.

Even if the term "fiber-reinforced semi-finished products" is often used in this sense, the following is generally referred to as coated fibers. Fiber-reinforced semi-finished products represent a preferred embodiment. In the following, a method and a device are described which ensure safe and reproducible wetting of individual fibers or fiber composites.

Basically all known fibers are suitable. Preferred fibers include carbon fibers, aramid fibers and glass fibers, natural fibers such as hemp or cotton, stone fibers such as e.g. Basalt fibers, plastic fibers or metal fibers (e.g. steel, copper, alloys). These fibers can be present as individual fibers, as filaments made of several fibers or as woven fabrics made of fibers or fiber composites. There can be a single type of fiber or mixtures of two or more different fibers. The fibers can have different cross-sections such as round, oval, triangular, square or any other polygons, or for example also as hollow fibers or multilayer fibers e.g. Co-extruded fibers, which have one or more layers, are present in one or more layers of coated fibers or also as fiber bundles (e.g. twisted, braided).

The fibers are wetted with a coating liquid. Plastic melts are used as the coating liquid. In the following, we will generally speak of “coating liquid”, which means these plastic melts. Preferred coating liquids are varnishes, paints, pigment-containing systems, single and multi-component resins, radiation-curing plastics (e.g. UV or electron beam curing) and all possible other crosslinking systems and combinations thereof.

The device for wetting fibers according to the invention comprises a fiber inlet, a liquid supply unit and a flexing unit, the flexing unit being designed in such a way that it has flexing areas in which the coating liquid is mechanically pressed into the fiber interspaces by movement or pressure, the Device preferably additionally has units by means of which the viscosity of the coating liquid (preferably in the area of the greatest flexing work) is reduced.

The function of the flex areas is to obtain a better incorporation of the coating liquid into the fiber interspaces.

The device represents an extrusion tool.

According to a preferred embodiment, the device additionally comprises at least one vacuum unit, in which a vacuum is generated around the material passing through. This is used for drying or degassing, for example. At least one vacuum unit is preferably connected upstream of the liquid supply unit and / or downstream of the flexing unit.

The inventors have found that there is a significant improvement in wetting if the viscosity of the coating liquid can be significantly reduced in the flex areas. This is achieved with the following preferred embodiments, which can preferably also be combined with one another.
The term “flexing areas” includes those areas of the flexing unit in which the fibers are wetting by force (often mechanical forces). These walking areas are wave crests or wave troughs of a wave-like guidance.

According to a preferred embodiment, the viscosity of the coating liquid is reduced by vibrations (e.g. sound, in particular ultrasound). For this purpose, the device preferably has sonotrodes, by means of which the sound (in particular ultrasound) is radiated into the coating liquid or the relevant walking area. The sonotrodes are preferably arranged in the walking areas and / or shortly before (max. 5 cm in front) in such a way that they emit sound (in particular ultrasound) into the liquid.

According to a preferred embodiment, the viscosity of the coating liquid is reduced by microwaves or heating elements. As the liquid heats up, the viscosity drops.
For this purpose, the device preferably has microwave sources or other heating elements (for example ohmic or capacitive heating elements) by means of which the coating liquid or the relevant walking area is heated.

The microwave sources or other heating elements are preferably arranged in the walking areas and / or shortly before (max. 5 cm in front) in such a way that they radiate microwaves or heat into the liquid. It goes without saying that if electromagnetic radiation (e.g. microwave radiation) is used, it must be ensured that either the matrix material or the fibers themselves can absorb this electromagnetic radiation.

The viscosity of the coating liquid is therefore preferably reduced in each case at the location of the deflection, that is to say where the highest mechanical load on the dressing occurs, or shortly before a viscosity-reduced liquid enters the flexing area. The term "shortly before" means that the effect of the viscosity-reducing measure must not have waned before the flex area. Preferred distances are the maximum 5 cm mentioned above or only max. 1 cm.

According to a preferred embodiment, the device comprises flexing rollers which are in particular driven and / or heated. These flex rollers are arranged one behind the other and / or one above the other, preferably not touching one another in the case of an arrangement and preferably exerting a pressure (in particular> 1 bar) on the liquid-impregnated fibers when arranged one above the other. This can e.g. can be achieved in that at least one of the rollers is movably supported and is pressed onto the other roller by a force (e.g. spring force or weight).

The fulling rolls are arranged in such a way that fibers running over the fulling rolls alternately run over the top and bottom of adjacent fulling rolls and this results in a wavy guidance. This wave movement can run horizontally or vertically or as a combination of these two spatial directions.

As a wavy guide of fibers in a block, flexing rollers are arranged in particular in the deflection regions of these shafts.
Additional flexing work is generated by the flexing rollers, which lowers the viscosity. In this case, the shafts are combined with the flex rollers.

According to a preferred embodiment, the flexing rollers are spherical in shape, so that they no longer have a cylindrical shape, but rather the Shell surface is convex with respect to the longitudinal axis. Alternatively or in combination, the surface preferably has a channel guide in the direction of the circumference or a surface provided with an embossed pattern. These configurations lead to a broadening or narrowing of the fiber bundles.

According to a further preferred embodiment, the surface of at least one fulling roll has a surface texture. Preferred surface textures are corrugations, tenons, grooves, teeth and needles. Opposing flexing rollers are preferably shaped in such a way that their surfaces interlock, i.e. the surface textures are each designed so that protrusion of one flexing roller can engage in retrusion of the opposing flexing roller (e.g. similar to two gear wheels, which represent a preferred embodiment). In this way, wetting of the surface of the fibers can be further improved.

The flexing work can be additionally increased by rotating these flexing rollers at different relative speeds to the fibers and / or by mounting the flexing rollers eccentrically.
According to a preferred embodiment, the device comprises at least one movement unit which is designed to rotate two of the flexing rollers at different speeds and or in different directions (of course about their longitudinal axis).
According to a preferred embodiment which can be combined therewith, the device comprises at least one eccentrically mounted fulling roller.

According to a preferred embodiment, the flexing unit comprises flexing rollers which, in addition to flexing, also take over the guiding of the fibers. This is achieved in particular by arranging the rolls as calenders. The coating of the fibers with a coating liquid preferably takes place at least in part in the calender, in particular in that the coating liquid is applied to at least one flex roll by means of nozzles or channels and is connected to the fibers by means of this. The pressure prevailing in the calender nips also has an advantageous effect on the wetting. There are many ways of arranging fulling rolls. A 1-, F- or Z-shape is preferred. The whale rolls are preferably heated. It is also preferred to pass the fibers through more than one calender arrangement.

According to a preferred embodiment, the device comprises units for heating the fibers. Preheating the fibers has an advantageous effect on the coating.

According to a preferred embodiment, the device comprises at least one deflection roller, in particular a plurality of deflection rollers, which are in particular tempered.

The layer of fibers is preferably introduced on at least one side, in particular on both sides, of the conveyed coating liquid, in particular by means of deflection rollers. The fibers move towards the coating liquid in the direction of movement of the coating liquid in order to bring the fibers and coating liquid into contact with one another.

A particular advantage of this embodiment is that two or more different types of fibers or types of fabric can be incorporated into a fixed composite.

According to a preferred embodiment, functional foils run together with the fibers through the device, e.g. to achieve optical effects or special surface properties. For this purpose, the device is preferably designed in such a way that at least one functional film can be introduced parallel to the fibers.

According to a preferred embodiment, at least one ultrasound sonotrode is arranged in the region where the coating liquid and fibers are brought together in order to further reduce the viscosity of the coating liquid.

According to a preferred embodiment, the device, preferably in its unit for supplying liquid, comprises special distributors for optimally distributing the liquid. Since the coating liquid usually has a viscosity that cannot be neglected (eg when using plastic melts), a good distribution over an area with several fiber strands or fiber fabrics is not trivial. Herringbone distributors are generally used in the prior art.
To distribute the coating liquid, distributors are preferably used which resemble deer antlers. "Deer antler distributors" are preferred, a form from which smaller, parallel side channels branch off from a main channel and have outlets for the coating liquid at their ends. However, since different angles and radii can occur for the melt in this type of distributor despite the same path lengths, irregularities in the melt flow sometimes occur, which can be achieved by deflecting the melt perpendicular to the distribution direction (e.g. upwards and backwards) at suitable positions , in or shortly after the respective sub-distribution. This neutralizes the different flows and speeds in the melt. Those distributors in which a reversal of the melt flow takes place are also preferred.

Even if these distributors preferably serve the flow of the coating liquid, embodiments are also preferred in which such distributors are used for splitting and guiding fiber bundles.

According to a preferred embodiment, the device comprises at least two nozzles arranged one behind the other in the direction of movement of the fibers, which nozzles are designed so that different materials can be introduced through them in the direction of the fibers and / or at least one nozzle by means of which a coextruded material (in particular a multilayered material) Material) can be introduced in the direction of the fibers (hereinafter also referred to as "multi-layer nozzle").
Using this embodiment, it is possible to bring multiple layers into contact with the fibers simultaneously (with the multi-layer nozzle) or in succession (with two or more nozzles) and embed them in a multi-layer matrix. It is preferred that the coating liquid which comes into contact with the fibers first has a lower viscosity than the coating liquid which is subsequently introduced. When using multi-layer nozzles, it is preferred if the viscosity of the coating liquid is so great that it is not possible to mix the individual layers, in particular the layer which is closest to the fiber composite has a lower viscosity than that layer, which follows the first-mentioned layer. The low viscosity favors wetting, while the higher viscosity of the following layer or coating liquid is advantageous for good embedding of the coated fibers in the multi-layer dressing. The viscosity differences can be achieved, inter alia, by different materials or else by different temperature control or crosslinking reactions of the materials.
In this way it is possible, for example, to provide a separating layer which wets the fibers and additionally to apply an outer layer with other properties which, on their own, would not adhere well to the fibers.
It is also preferred that the nozzles on the top and bottom of the device are designed differently and / or the device is designed to apply different coating liquids to the fibers via the nozzles on the top and bottom. This enables the production of materials with different surfaces (different front and back).

This embodiment for coating fibers with several layers can certainly be an independent invention. The device according to the invention for multilayer wetting of fibers in this case comprises a fiber inlet, a unit for supplying liquid and a flexing unit, which is preferably connected downstream of the unit for supplying liquid with respect to the fiber movement, the flexing unit being of such a nature that it has flexing areas in which through Movement or pressure causes the coating liquid to be mechanically pressed into the fiber interspaces, the device additionally comprising at least two nozzles arranged one behind the other in the direction of movement of the fibers, which nozzles are designed so that different materials can be introduced through them in the direction of the fibers and / or at least has a multi-layer nozzle.
The prior art has so far only been able to produce a single-layer coating, that is to say the embedding of fibers in a uniform matrix. The object of the independent invention was to overcome the disadvantages of the prior art and to provide an apparatus and a method by means of which a user is able to carry out a cost-effective, continuous production of multi-layer coated fibers.

According to a preferred embodiment, at least one nozzle for introducing coating liquid is also arranged in the flexing unit, in particular behind the first flexing area, so that the fibers can be coated once more (in particular with another coating liquid) after a first flexing. In this way, a very good composite can be produced in which fibers are embedded in a multi-layer matrix. The fibers are coated, this layer wetting the fibers well by milling, then applying a further layer and improving the wetting of the fibers and the cohesion of the layers by further milling. In this way, several layers can be optimally connected to one another and to the fibers. However, it is preferred that after the last layer has been introduced (the last time a coating liquid has been introduced), the material passes through at least one further fulling area, so that it is tumbled at least once more.

According to a further embodiment, the viscosity of the coating liquid is reduced by vibrations, in particular pressure vibrations or electromagnetic vibrations (for example vibrations such as sound, in particular ultrasound, or microwaves / infrared rays), the elements for transmitting the vibrations (for example sonotrodes or microwave sources or IR radiators) are designed so that they emit discrete wavelength ranges, the mode frequency width of which is more than 10 times (in particular more than 100 times) smaller than the maximum of the respective mode, and which are designed to transmit at least one on a specific absorption line to emit the coating materials.
In this way it is possible to specifically reduce the viscosity of one of the coating materials (for example that of the innermost layer), while the viscosity of the other coating materials (for example that of the outer layers) is not reduced. Thus, if a multilayer composite is present during the flexing process, the viscosity of the innermost layer can be reduced for better wetting while the layer structure remains undisturbed.
Vibrations in narrow frequency bands are only absorbed by materials whose absorption lies in the frequency range of the vibrations.

According to a preferred embodiment, the device has a modular structure and comprises segments from the group of inlet segments, preheating segments, coating segments (for coating on one or both sides), fulling segments, vacuum segments, cooling segments, rolling segments and smoothing segments.

The fibers for coating are preferably placed under tension so that they are arranged straight in the later matrix. For this purpose, the device preferably comprises at least one unit for tensioning the fibers. This can e.g. be realized by a roller arrangement over which the fibers run and which put the fibers under tension via a spring mechanism.

The invention also includes fibers which have been produced by means of a device according to the invention or by means of a method according to the invention. This can be easily tested, for example, by measuring the degree of wetting. If more than 95%, in particular more than 98%, of the fibers are wetted by the liquid, and the wetting liquid has a viscosity of more than 10000 mPa * s during normal coating, it is highly likely that the invention manufactured product.

• 1 zeigt schematisch eine bevorzugte Ausführungsform.
• 2 zeigt schematisch eine weitere bevorzugte Ausführungsform.
• 3 zeigt eine bevorzugte Ausführungsform der Walkeinheit.
• 4 zeigt eine weitere bevorzugte Ausführungsform der Walkeinheit.
• 5 zeigt schematisch eine bevorzugte Ausführungsform.
• 6 zeigt schematisch eine bevorzugte Ausführungsform.
• 7 zeigt schematisch eine bevorzugte Ausführungsform.
• 8 zeigt schematisch eine bevorzugte Ausführungsform.

Examples of preferred embodiments of the device according to the invention are shown in the figures.

• 1 shows schematically a preferred embodiment.
• 2nd shows schematically another preferred embodiment.
• 3rd shows a preferred embodiment of the flexing unit.
• 4th shows a further preferred embodiment of the flexing unit.
• 5 shows schematically a preferred embodiment.
• 6 shows schematically a preferred embodiment.
• 7 shows schematically a preferred embodiment.
• 8th shows schematically a preferred embodiment.

To begin with, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, and the disclosures contained in the entire description can be applied analogously to the same parts with the same reference numerals or the same component names. The location information selected in the description, e.g. above, below, to the side, etc., referring to the figure described and illustrated immediately, and if the position is changed, these are to be applied accordingly to the new position.

FIGURE DESCRIPTION

1 schematically shows a preferred embodiment, in particular its side view. the device for wetting fibers comprises an inlet for the fibers 3rd (left), a hydration unit 1 , the coating liquid 4th through ducts at the top and bottom and brought into contact with the fibers shortly before the end of the liquid supply unit. In this embodiment, sonotrodes are 5 already in the area of the fluid supply unit 1 arranged in which the first contact of fibers and coating liquid 4th takes place to ensure good contact already there. Nevertheless, the wetting of the fibers with the coating liquid can often be improved.

From the hydration unit 1 occurs the composite of coating liquid 4th and fibers 3rd into the flexing unit 2nd one, which here comprises a block into which a wave-like guide has been introduced. The reversal areas in the wave peaks and valleys are the walking areas. In these there are sonotrodes to reduce the viscosity 5 arranged. An intimate cohesion of the composite with a very good wetting of the fibers with the coating liquid is generated in the flexing unit.

2nd schematically shows a further preferred embodiment, which is a further development of the embodiment according to 1 is. In addition were rolls in the walking areas 6 arranged, which achieve an additional reduction in the viscosity of the coating liquid by their movement and / or the pressure they exert. This further optimizes the wetting of the fibers with the coating liquid.

3rd shows a preferred embodiment of the flexing unit 2nd , for example in side view. From a hydration unit 1 , which here is, for example, a unit for supplying a plastic melt, becomes a coating liquid 4th , for example a viscous melt strand or a melt surface, between two opposing laminating jaws in the flexing unit 2nd introduced. In the following, for the sake of clarity, we speak of a “melt” instead of a coating liquid.

Together with the melt, fibers become from above and below 3rd and functional foils 8th into the flexing unit 2nd introduced. This is done, for example, via deflection rollers, as shown as circles in the figure. To improve the guidance runs between the walls of the flexing unit 2nd and the composite of melt, fibers 3rd and functional foils 8th a conveyor belt 7 , which is designed as an endless belt, and transports this composite through the flexing unit.

In the area of the flexing unit 2nd , in which a mechanical pressure is exerted on the above-mentioned composite via the walls, sonotrodes can be used at the top and bottom to reduce the viscosity 5 are located, which radiate ultrasound in the walking area.

The fibers and also the functional film can be preheated to prepare for contact with the melt. This is preferably done using heating elements 9 , which are advantageously arranged in the laminating jaws.

This figure also shows the preferred embodiment, in which a calender is additionally located downstream 10th is arranged with a calendering nip in which the product can be treated further.

In 4th is a similar structure as in 3rd also shown in side view. The fibers 3rd and the functional film 8th are not introduced here via laminating jaws, however, using laminating rollers. There are fibers between the lamination rolls 3rd , functional film 8th and the coating liquid 4th brought into intimate contact by means of mechanical pressure.

Although no ultrasound or heating means are shown in this figure, they can also be located at the corresponding points.

In order to achieve an optimal effect of the ultrasonic waves or to ensure a good regulation of the temperature, it is generally advantageous if the laminating rollers are shaped as rollers with a wall thickness of at most one cm, in particular less than 0.5 cm, in their Inside, if necessary also in the wall, there are heating elements or sonotrodes. Here, too, is a preferred calender downstream 10th shown.

5 shows a modification of the in 1 illustrated embodiment. There are additional channels in the flexing unit in front of two flexing areas for the passage of a coating liquid 4th . The fibers 3rd run through the hydration unit 1 a, with a first coating liquid 4th coated, which also shows the option that sonotrodes 5 already in the area of the fluid supply unit 1 are arranged.

From the hydration unit 1 occurs the composite of coating liquid 4th and fibers 3rd into the flexing unit 2nd and passes through a first walking area, which here is optionally with a sonotrode 5 is equipped in order to achieve good wetting of the fiber with the first coating liquid by means of the viscosity reduced thereby. Another coating liquid is located behind the first fulling area 4th added to the composite, this coating liquid 4th compared to the initial coating liquid 4th can be the same or different, and the coated composite passes through another flexing unit (which also has an optional sonotrode 5 Is provided). After this flexing a third coating liquid 4th applied for the same as for the second applied coating liquid 4th applies, and the composite continues to roll, whereby in the 5 two walking areas perform this task. This final walk through, which is improved with the sonotrodes shown, creates an intimate cohesion of the layers with one another and the innermost layer with the fibers.

In the 6 to 8th various preferred embodiments are sketched, in which the flexing units 2nd are designed by calender arrangements. The liquid supply unit is also located in the same area 1 . The milling thus takes place with the introduction of the coating liquid 4th . The fiber 3rd is always between rolls 6 guided and thereby coated and this coating rolled in.

In 6 the walk is done by means of two rolls 6 . Coating liquid is applied from below via a channel or a nozzle 4th on the whale roll 6 applied and comes from the rotation of the fulling roll 6 with the fibers 3rd in contact. A second possibility is drawn in above, in which the coating liquid 4th right on the fibers 3rd or even directly into the calender gap. The emerging fibers 3rd are coated and can be smoothed and / or dried in optional units.
In 7 is a similar arrangement as in 6 just to see that different coatings take place in different pairs of flex rollers.
In 8th is an I-shaped calender arrangement of fulling rolls 6 shown. Although the coating liquid is introduced here on different pairs of flex rollers, it could also be done on a single pair of rollers.

It is also added that a multilayer composite also with the embodiment according to 1 can be achieved if the supply for the coating liquid shown there 4th is designed for the introduction of a multilayer, viscous liquid composite, for example a co-extruded plastic melt consisting of several layers. The sonotrodes 5 would be optional but preferred in this case.

The exemplary embodiments show possible embodiment variants of the invention, it being noted at this point that the invention is not restricted to the specifically illustrated embodiment variants thereof, but rather also various combinations of the individual embodiment variants with one another are possible, and this variation possibility is based on the teaching of technical action by means of representational ones Invention lies in the skill of those skilled in the art.

Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

The object on which the independent inventive solutions are based can be found in the description.

All information on value ranges in the present description should be understood to include any and all sub-areas from it, for example, the information 1 to 10th to understand that all sub-areas, starting from the lower limit 1 and the upper limit 10th are included, ie all sub-areas begin with a lower limit of 1 or greater and end with an upper limit of 10th or less, for example 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

Above all, the individual designs shown in the figures can form the subject of independent solutions according to the invention. The relevant tasks and solutions according to the invention can be found in the detailed descriptions of these figures.

For the sake of order, it should finally be pointed out that, for a better understanding of the structure, the figures or their components were sometimes not shown to scale and / or enlarged and / or reduced.

Reference symbol list

1

Liquid supply unit

2nd

Whale unit,

3rd

fiber

4th

Coating liquid

5

Sonotrode

6

Fulling rolls

7

Conveyor belt

8th

Functional film

9

Heating element

10th

calender

Claims (11)

Extrusion tool for wetting fibers, comprising a fiber inlet and a unit for supplying liquid, characterized by a flexing unit which is of such a nature that it has flexing areas which are designed as a wavy guide in a block and in which by movement and / or pressure mechanical pressing of a coating liquid designed as a plastic melt into fiber interspaces is effected. Extrusion die after Claim 1 , characterized in that it additionally has at least one unit by means of which the viscosity of the plastic melt is reduced and / or comprises at least one vacuum unit in which a vacuum is created around the material passing through, preferably at least one vacuum unit being connected upstream of the liquid supply unit and / or is connected downstream of the flexing unit. Extrusion tool according to one of the preceding claims, characterized in that the extrusion tool is designed to control the viscosity of the plastic melt by ultrasound, To reduce microwaves or heat, the extrusion tool preferably comprising sonotrodes, microwave sources and or heating elements, which are arranged in particular in the flex areas and / or at most 5 cm in front such that they emit ultrasound, microwaves and / or heat into the plastic melt. Extrusion tool according to one of the preceding claims, characterized in that the flexing unit comprises flexing rollers which are in particular driven and / or heated and which are arranged one behind the other and / or one above the other, wherein flexing rollers arranged one behind the other are preferably arranged such that fibers running over the flexing rollers alternate Run over the top and bottom of adjacent flex rollers and this results in an alternating guidance of the fibers, which are arranged in particular in the form of a calender. Extrusion tool according to one of the preceding claims, characterized in that the flexing unit comprises flexing rollers which are spherically shaped. Extrusion die after Claim 5 , characterized in that the flexing rollers rotate at different relative speeds to the fibers and / or that the flexing rollers are mounted eccentrically. Extrusion tool according to one of the preceding claims, characterized in that it has heating elements in order to heat elements of the flexing unit to temperatures between 30 ° C and 700 ° C, in particular between 150 ° C and 450 ° C. Extrusion tool according to one of the preceding claims, characterized in that at least one ultrasound sonotrode is arranged in the region of the joining of plastic melt and fibers in order to further reduce the viscosity of the plastic melt. Extrusion tool according to one of the preceding claims, characterized in that it comprises, in its unit for supplying liquid, special distributors for optimally distributing the plastic melt, and / or that it comprises distributors for splitting fiber bundles, preferred distributors being “deer antler distributors” or distributors with reversing melt flow are. Extrusion tool according to one of the preceding claims, characterized in that the extrusion tool comprises at least two nozzles arranged one behind the other in the direction of movement of the fibers, which are designed so that different materials can be introduced through them in the direction of the fibers and / or comprise at least one nozzle, by means of which a co-extruded material can be introduced in the direction of the fibers, the nozzles on the top and bottom of the extrusion tool preferably being configured differently and / or the extrusion tool being designed to apply different plastic melt to the fibers or onto the nozzles on the top and bottom Introduce fulling rolls. Extrusion tool according to one of the preceding claims, characterized in that the extrusion tool has elements for emitting vibrations, in particular sonotrodes or microwave sources or IR emitters, which are designed so that they emit discrete wavelength ranges, the mode frequency width of which is more than 10 times is smaller than the maximum of the respective mode, and which are designed to emit at least one of the coating materials on a specific absorption line.

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