DE19853866A1 - Coating fibers, filaments or wires comprises drawing through plastics emulsion, heat fusing and repeating to give required coating thickness - Google Patents

Abstract

To apply a coating to fibers or filaments (2) or wires, they are drawn through a plastics emulsion (6). The coated materials are dried (14) and the coating is fused (18). The process is repeated a number of times. After the coating has been fused, they are shaped conventionally, such as by shaping rollers (22), and are cooled after the coating has been melted and/or the shaping stage. After being drawn through the plastics emulsion, surplus coating is removed mechanical, pneumatically or by stripping (12). The coated filaments/wires are dried in a high frequency field, and especially by microwaves, which are also used to heat polar plastics. After filling the interior of a fiber, the emulsion is also filled with pigments, also to be taken in with the coating. The plastics heating stage has a pipe with an elliptical cross section, for the filaments/wires to move on one center point line and a heated filament is along the other center point line. The microwaves are contained within a hollow waveguide, where the waveguide length sets the heating effectiveness. The composition of the plastics emulsion is held at a constant level, with or without pigments, and it is stirred with possible addition of fluid and also of emulsion with pigments. All the process stages are effected vertically and, in all the stations, the filaments/wires follow a zigzag path to reduce the length of each station. A number of filaments/wires are gathered into a band, to be processed together. The fiber:polymer ratio is set by the thickness of the coating. The absorption and reflection of the finished product are set by the added pigments. The finished filaments/wires are woven and ironed to give a woven film material, with a woven film pattern through filaments/wires of different characteristics.

Description

State of the art

For the production of armored foils resp. Fiber-plastic composites and for others Applications are used almost exclusively with plastic-coated threads, wel che can be obtained by extruding the plastic around the core material becomes. For this purpose, the fibers or wires are passed through the sleeve of an extruder and then provided with a plastic covering all around.

The insulation material is applied around wires in the same way.

Plastic emulsions are currently either used as a coating material or in a very highly filled form as a paste for spreading on fabrics. In the latter case If the paste is scraped onto fabric in appropriate systems, PVC pastes are applied Polyester fabric or PTFE pastes on glass fabric. In a downstream heater zone, both the water is expelled and the plastic is liquefied. Further smoothing processes end the coating process. In the case of the PTFE this material through high temperatures by means of connecting polymers z. B. PFA on that Sintered glass fabric.

Problems

Although the process of extrusion is mature and used almost without exception there are still some problems.

The main problem is the high price for such an extruder line. Since the system is not consists only of the extruder, but especially the periphery is particularly complex and is expensive, considerable investments must always be made.

Another problem arises when a particularly thin plastic covering is desired. Here the usual process with some polymers reaches its limits, so that it is sometimes impossible to carry out such minimal coatings.

The application using extruders becomes particularly critical when there is a high proportion of solid substances is present in the polymer. As a result, the flow behavior of the plastic affects that sometimes an order is almost impossible.

Another problem arises when coating fibers. Since the polymer from au When air is applied, the air remains in the fiber, which means that the air cushion is clear remains visible, making the fiber appear white and large, and on the other hand, the haf tion is also not good, since the plastic only contacts the fiber on the outer fibers has core.

Since the adhesion of plastics to the fiber used is sometimes very bad, let some composites did not form at all.  

Furthermore, the conventional method can also be used for coextrusion also apply other plastics, but here the quill is particularly critical table and it takes a very long time to apply different plastics gen. Here it is a prerequisite that the processing temperatures below different plastics is similar, since they are applied over the same quill.

In the known coating processes with pastes, very complex measures are required seem to do this. The penetration is due to the high viscosity of the pastes very limited in fiber materials. For this reason, some fibers are special not to coat their polymers in this way.

The coating carried out in this way makes it almost impossible to use pigments that must be applied oriented.

The tissue crossings also remain polymer-free, since the paste is not tight between them superimposed fibers can penetrate.

The paste can also be applied only over a large area, which means a sample presentation is possible.  

Problem solving

A method is ideal where fibers, threads or wires can be easily mixed with any Plastic of any thickness can be encased.

It would also be desirable if not only a wide variety of plastics were applied could be, but there is always liability for fibers, even then, if the materials do not stick together. Furthermore, all the disadvantages of the Paste order can be avoided.

Such an ideal process should also allow a high proportion of filler to be used stratification not hindered. If coated particles are incorporated, si be made that their alignment along the thread is possible.

Several thin layers of different plastics should also be possible.

Ultimately, the process should be as energy-saving as possible.

The method according to the invention with the device according to the invention offers the solution tung.

Only if very thick layers are to be applied, must be examined whether extrusion may be more economical.  

Coating of fibers, threads and wires with plastic emulsions

Plastic emulsions are already widely used. Mainly in the Be rich in paints or when coating fabrics with very high fill Emulsions in the form of pastes.

In contrast, in the method according to the invention only individual fibers, threads or Wires or limited quantities thereof are coated with emulsions as a band-shaped bundle.

This is done in such a way that, for. B. the fibers, which were mainly discussed here gene is passed through an appropriate plastic emulsion. This fills the Fiber with the emulsion, the amount of plastic absorbed at a certain Fiber is determined by the emulsion strength and also the pulling speed.

The residence time of the fiber in the emulsion can also affect the plastic have a lot.

Care must be taken that the polymer concentration when pulling the fibers preserved.

If the fiber is pulled out of the emulsion, this should preferably be done that the fiber is guided almost perpendicular to the surface of the emulsion. This will ensures that there is no asymmetrical dripping of the excess material as well as an uneven application of plastic.

After the emulsion has been left, the excess material can be stripped off become. This can be done by a mechanical or a pneumatic Ab stripes happen. After this, the fiber filled with the emulsion must be in a first state to safely get rid of any liquid. This can be done by using the fiber is heated and then the water evaporates. Heating over hot air can accelerate this process of drainage.

Another possibility of drainage is given by the wet fiber is guided through a microwave field and thereby heats up all polar materials the. This ensures that the energy used is also open without exception heating of the direct fiber environment is used.

After passing through the dewatering station, the fiber runs through a melting station. Here the plastic located in and / or on the fiber is melted. This can be done certain reasons either be a very short process to get the plastic on the Fix surface of the fiber material or a complete melting process so that the liquid plastic can contract and a closed surface as possible che forms.  

In the case of polar plastics, this melting can also take place by means of a microwave field conditions, but also by hot air or by radiant heat.

In the case of hot air, the flow of air can on the one hand cause the liquid plastic to zen strand of the fiber or be balanced in the case of external order.

In the case of radiant heat, this can be a normal infrared radiator, on which the fiber is passed as close as possible or is even surrounded by it or it is a heater the one that is located in a center line of a tube reflector with an elliptical cross section finds and the fiber runs through the other center line.

Of course, combinations of the heating methods are also possible.

After the melting station, the fiber runs through a forming station. Because the plastic is still is plastic, the fiber can be z. B. regularly round be shaped.

Because the plastic intake over the emulsions is because of the out-of-roundness of fibers Seen in cross-section is not uniform, the form rollers or rollers force the Roundness on.

After the forming station, the fiber runs into the cooling station. Before the coated fibers Run over pulleys and possibly lose their roundness again, should it be cooled so that no deformation is possible due to the deflection pressure.

The cooling takes place optimally by air flow. In the z. B. tubular station air is blown in massively via a blower, thus cooling the coated fiber. The use of water as a coolant is also possible, be it e.g. B. as a bath or in shape a spray. However, water cooling can have a negative impact on the wide production steps because the thread that is still wet runs back into the emulsion.

Since a single pass will never bring enough plastic onto the fiber, several runs must be carried out. The number of runs also determines the loading layer thickness. The passages through the various sta tion necessary, from running through the emulsion, dewatering, melting, the Shaping until cooling.

If pigments are to be incorporated into the casing, the passage should be through the pigmented emulsion happen when the inner area of the fiber is filled with plastic.

If there are coated mineral tiles that are added, they will be optimal aligned longitudinally to the fiber by partially emitting the emulsion along the fiber the emulsion container runs back.  

When mixing pigments into the emulsion, care must be taken that the Ratios of pigments to the emulsion and polymer to water are retained.

Again, there are several runs for the build-up of a certain layer thickness necessary.

In the same way, other types of plastic can be applied in the the thread already coated with the polymer 1 is now through the emulsion of the poly mer 2 is pulled and goes through the previously described stations. this will again continued until the desired layer thickness is reached.

It is of course also possible to apply a layer of a third polymer.

Should several fibers to a z. B. band-shaped bundle, so this can be done with the last or the last runs in such a way that the almost completely covered threads from several continuous cascades on one Orientie tion roller converge and from there summarized by a continuous path to run. Hereby receives z. B. this band of many fibers from a common coating of the emulsion passed through and are melted together in the melting station zen and ultimately compressed into one unit in the forming station.

Furthermore, several threads can be pulled through several stations at the same time the and then further processed individually or together as a ribbon to get nabbed.

In this way, sheathing is possible even with very different materials Lich. Even if the polymer does not adhere to the fiber material at all, the Wrapping the individual fibers of the fiber bundle ensures perfect adhesion of the plastic achieved when all individual wrappings converge to form an overall sheathing.

Because the outer application of the polymer as an emulsion happens completely regardless of how high the polymers are filled with particles, also the sheathing with a high filled polymer is no longer a problem. Only when filling the inner area of a Fiber should only be used with unfilled polymer. Only with pigments, de ren particle size below the particle size of the emulsion would also be an internal Filling possible.

The aim must then be to keep the particles or particle size very small, so that they can easily get inside the fibers.

When pigments are added, lumps can form in the emulsion several particles couple to one pigment and thereby a significantly larger one Complex arises.  

It is also possible to work up the emulsion downstream to make it uniform again to get small particles. In this case, the pigment particles would only be thin Layer of the polymer surround, so they behave similar to the other poly particles.

In addition to the passage through elongated processing zones, if not a very high quality should be achieved, zigzag paths are also built where with the same processing steps.

It is then also possible to process several fibers over a larger width simultaneously sieren.

In this way, not only more compact systems are created, but also more economical chere procedures.

Even the shaping can be carried out in this way on appropriately designed rollers be performed. However, a certain ovality cannot be avoided. But will fabric made from it for later compression, this can sometimes be unbe remain considered.

The insulation of cables can also be carried out in this way. Instead of a fiber it is then here the wire which is led through the different processing stations.

Any fiber-polymer composites can then be made with the threads thus produced create. Since the threads can be equipped with different properties, e.g. B. clear polymer over a very thin fiber or different colors as body color or as reflectivity, any Mu are generated. So z. B. only quasi clear threads woven into one area be, which means that a later transparent surface as Window is created.

For the simulation of roofs z. B. woven a pan pattern, whereby After pressing, a waterproof fabric film is created that is as permanent as a Tile roof looks like.

Luminous pigments can also be incorporated into the polymers, which un with at night visible UV light are then illuminated and then emit visible light. Because here too different pigments can be incorporated, patterns are also possible with this or by using three colors that lie together but are different daylight color can also be generated.

It would also be possible to produce pigments or, even better, the smallest plates from filter glass ren and hereby build a short pass filter for UV. Threads that be with fluoropolymer are layered and then can still contain this pigment then ultimately to film weaving are processed, which in turn are waterproof, shadows in the visible  Provide light and possibly also block the IR, but are UV transparent. Essential The long pass function is easier to represent, with the installation of ultra-fine Titanium dioxide as a pigment in fluoropolymers makes the finished material transparent to the visible range, but all UV light is filtered out.

The enumeration of the many examples is only intended to show the almost unlimited variety of possibilities are shown which arises from the fact that the threads according to the invention produced over polymer emulsions and then only woven and then pressed.

This is impossible with conventional methods.  

The method according to the invention and a possible form of the devices required for this are illustrated with the aid of FIGS. 1 to 7.

The following details are shown:
From the roll 1 , the fiber 2 runs through the brake 3 on the guide roller 4 in the emulsi onstopf 5th This contains the polymer emulsion 6 , which is kept homogeneous with a stirrer 7 . From a storage container 8 material runs after when the level sensor 9 shows that the set level is undershot by opening the valve 10 .

From the deflection roller 11 located in the emulsion pot 5 , the fiber runs to the surface of the emulsion 6 and passes through the stripping unit 12 , in which an air flow around the fiber is blown out through the air nozzles 13 and thereby excess liquid is rejected.

After that, the fiber 2 runs into the drying unit 14 , in which, in the example shown, air is blown into the duct 16 of the drying unit 14 via corresponding fans 15 after it has been brought to a high temperature via the heater 17 .

The fiber 2 then runs into the heating unit 18, in which air is in turn blown through the fans 19 and heating systems 20 into the channel 21 of the heating unit 18 .

After that, the fiber 2 runs through the forming unit 22 in which, for. B. a circular cross section is to be formed.

Finally, the fiber 2 passes through the cooling unit 23 , in which the fiber 2 is brought back to a temperature below the plastic state of the plastic. This happens in which air is blown by the blower 24 into the channel 25 of the cooling unit 23 ge.

The fiber is then fed back into an emulsion pot through the deflection rollers 26 . The other processing cascades are identical to those previously described.

In contrast, FIG. 1 only shows another cascade in which there are also pigments in the emulsion 26 . Here, too, there is a stirrer 28 in the emulsion pot 27 , which is even more important here, since the stirring should prevent the pigments from sedimenting.

Here, too, the liquid level 29 is held in such a way that material can flow in from the reservoir 30 via the valve 31 .

The fiber again passes through a stripping unit 32 , a dewatering unit 33 , a melting station 34 , a forming station 35 and ultimately a cooling unit 36 .

About the deflection roller 37 , the finished fiber 39 runs to the pull drum 38 , with which the water is drawn through all processing units and is held tight by the brake 3 .

Then the finished fiber 39 is wound on the winding unit 40 .

Fig. 2 shows a possible dewatering unit 41 , in which the thread 42 is guided through a waveguide 43 , in which 44 microwaves are fed by a magnetron.

Fig. 3 shows a channel 45 , in which the air channels 46 of several fan heaters 47 di open directly onto the thread 48 . This unit can be used for dewatering as well as for heating or without heating also for cooling.

Another heating unit is shown in FIG. 4. Here, the thread 50 is passed through a tube 49 with an elliptical diameter. The inner surface of the tube is heat reflecting. A heating wire 51 passes through the tube 49 at the other center of the ellipse.

The principle is shown in FIG. 5. The heat radiation 54 runs from the heating wire 52 in one center of the ellipse 53 to the continuous fiber 55 in the second center of the ellipse.

In FIG. 6, the fiber is zigzag guided by guide rollers 57 in the housing 56 58, wherein 59 microwaves are guided into the interior of the housing 58 through the magnetron.

Fig. 7 shows a variety of similar processing cascade 60 from which the threads 61 converge on a roller 62. The bundle 63 then runs through a further processing cascade 64 , which is designed to form a band-shaped bundle.

Claims (17)

1. The method and device for coating fibers, threads and wires, characterized in that they are drawn through a plastic emulsion, then dried and melted and this process is carried out several times. 2. The method and device according to claim 1, characterized in that the Plastic-covered fibers, threads or wires after melting the art with appropriate measures, e.g. B. form rolls are formed. 3. The method and device according to one or more of claims 1 to 2 thereby characterized in that the plastic-tied or coated threads after the Melt and / or molds are cooled. 4. The method and device according to one or more of claims 1 to 3 thereby characterized in that after passing through the emulsion, the excess Ma material is removed by a mechanical, pneumatic or other wiper. 5. The method and device according to one or more of claims 1 to 4 thereby characterized in that for drying the threads high frequency fields, in particular Microwaves are used. 6. The method and device according to one or more of claims 1 to 5 thereby characterized in that for heating polar plastics high-frequency fields, ins special microwaves are used. 7. The method and device according to one or more of claims 1 to 6 thereby characterized in that after filling the inside of a fiber, the emulsion also with Pigments is filled and these are also included in the coating. 8. The method and device according to one or more of claims 1 to 7 thereby characterized in that the heating of the plastic in a tube with an elliptical Cross-section in the meadow happens that the thread runs in a center line and a filament is in the other center line. 9. The method and device according to one or more of claims 1 to 8 thereby characterized in that the microwaves are held in a waveguide and the threads run through this waveguide, the effectiveness of the heating by the length of the waveguide can be adjusted. 10. The method and device according to one or more of claims 1 to 9 thereby characterized in that the emulsion obtained with or without pigments in their setting remains by stirring it and possibly adding liquid and even emulsion or pigments may be added. 11. The method and device according to one or more of claims 1 to 10 thereby characterized in that all process steps are carried out vertically. 12. The method and apparatus according to one or more of claims 1 to 11 thereby characterized in that the thread guide runs zigzag in all stations and thereby the design of the stations will be shortened. 13. The method and apparatus according to one or more of claims 1 to 12 thereby characterized in that several threads together to form a band-shaped composite are managed and processed together. 14. The method and device according to one or more of claims 1 to 13 thereby characterized in that the fiber / polymer ratio by the thickness of the coating is set.   15. The method and device according to one or more of claims 1 to 14 thereby characterized in that the absorption and reflection by the pigments used of the finished product. 16. The method and device according to one or more of claims 1 to 15 thereby characterized in that the finished threads are then woven and ironed and this creates a fabric film. 17. The method and device according to one or more of claims 1 to 16 thereby characterized in that threads with different properties are inserted during weaving be placed and this pattern is then ironed and thereby a patterned Ge woven film is created.