WO1998027250A2 - Reinforced plastic foil - Google Patents

Abstract

In order to produce reinforced plastic foils, a material is used whose lead threads (1) consist of a core (2) and a synthetic coating (3). The synthetic coatings are laterally extended by processing in a calendering unit and subsequently form a closed reinforced foil (4).

Description

 Armored plastic film

The invention relates to a process for the production of reinforced plastic films in particular.

Plastic films of all kinds are produced, for example, on extruders with a slot die and processed on calender rolling mills. The film thickness is adjusted by the slit size and the train speed or the gap width of the calender rolling mills.

In the case of foils with a support or reinforcement material, extrusion is usually carried out directly onto the support material.

The manufacturing process is particularly critical if the support material is to be in the middle of the finished film. In the prior art, this is achieved in that the support material is guided between two slot nozzles and the plastic material is extruded on both sides. Care must be taken to ensure an exceptionally uniform flow of material from the two slot nozzles.

In the case of foils which have a reinforcement made of plastic and whose softening temperature lies in the region of the plastic material surrounding the reinforcement, the production is particularly problematic when the reinforcement is a fabric. This warps very easily when the hot film material flows onto the support material. Furthermore, there is a danger that the tensioned tissue becomes so hot that it softens after the application surface and then tears.

Another problem can arise from the fact that the film is oriented in the pulling direction due to the production method and behaves differently to the direction at higher temperatures. The invention has for its object to provide a simplified method for the production of plastic films, in particular reinforced plastic films.

This task is performed according to a procedure. one of claims 1 to 3 solved. Appropriately manufactured plastic threads are first woven and then pressed on a calender so that the threads are welded together and a homogeneous, closed film is produced.

Since the surface of the film is only created by calendering, the surface quality of the thread is of secondary importance. There is also no need for an expensive or large extruder, just a small machine that enables threads of small diameter to be drawn.

Reinforced foils can be produced particularly easily with the methods according to the invention. This is done in such a way that an envelope is extruded onto the core material. Such covered threads are then woven and the fabric is processed in a calender. The sheath material of the threads is brought to close by physical and / or chemical softening processes, whereby the reinforcing fabric is surrounded on both sides by closed plastic material. By adjusting the tensile force in the calender, it can also be ensured that the core material runs straight in the tensile direction, so that there is no subsequent stretching during later use.

Since particularly elastic fluoropolymers are difficult to pull into films, the processes are particularly suitable for such materials.

The transparency and durability of fluoropolymer films is desirable for a large number of applications. However, since the load capacity of the known films is limited at the same time, they can often not be used for the desired purposes. In contrast, z. B. Reinforcements made of metal, glass or quartz fabric incorporated into the film results in a high-strength fluoropolymer film with excellent chemical, optical and mechanical properties.

Since the reinforcement threads z. B. only make up about 10% of the area of the film, the optical property is impaired to a very small extent. The reinforcement is enveloped in an airtight and water vapor-tight manner by the fluoropolymer, so that the reinforcement is absolutely corrosion-resistant, for example when using metals.

For example, the use of stainless steel or quartz reinforcements can give the film such strength that very long distances can be covered. Due to the absolute UV stability of the fluoropolymer, such a material can be used particularly well for roof structures. But it can also replace the translucent walls of a greenhouse. Since the fluoropolymers in particular are also UV-transparent, the use of the reinforced fluoropolymer films also ensures optimal, UV-rich light in greenhouses and other buildings. The use in amusement parks is also very holiday-compliant, because in spite of the airtight roof construction, the natural sun radiation is fully used.

For such purposes it is also possible to impart light-absorbing or scattering or other optical properties to the fluoropolymers by means of certain ingredients.

For example, ultrafine titanium dioxide can be used as an additive, whereby z. B. harmful UV components are absorbed.

Color effects depending on the angle of incidence of the light can also be achieved.

However, it is also possible, for. B. mica flakes or aluminum Work in nium foil pieces that produce appealing optical effects.

With the reinforced fluoropolymer films, however, luminescent pigments can also be used in the sheathing plastic. These can then be excited using appropriate UVC radiation.

Since fluoropolymer films do not weather, it is useful wherever other plastic covers become brittle and yellow.

The high gas tightness of the fluoropolymer also allows that a double-walled film is used and the space z. B. is filled with helium. By correctly adjusting the cushion size, the gas volume can be adjusted so that the weight of the entire roof structure is compensated for by the buoyancy of the filling gas. Since helium in particular can diffuse more easily through plastics, a very thin layer can be applied on the inner surfaces to ensure that helium does not diffuse. This can e.g. B. be a very thin aluminum layer, the optical properties are only slightly affected.

As already mentioned, other core materials can also be used in addition to steel threads. In particular, high-strength plastic threads, glass or quartz fibers or other metal wires can be used. Reinforcing fabrics can be used in the production methods according to the invention, which result in a restoring force which counteracts a flow of the elastomer. With such a reinforcement fabric, for. B. when weaving the warp thread very tight and the weft thread very loose, so that there is a very straight core wire in the direction of travel and a wave-shaped cross-wire when formed into the film.

In this way, a flexible, but also elastic reinforced plastic film can be produced, which, for. B. as UV-trans Parent film can be used for sunbeds.

If a larger distance between the core fabric is desired and this can no longer be adjusted by the jacket thickness, then this can also be achieved by weaving the construction fabric in such a way that one or more yarns of pure jacket material lie between the jacketed threads and thereby one Any distance from the core material thread to the next can be set.

The distance between the core threads results from the sheath volume and any intermediate threads made from sheath material and the desired film thickness.

To convert the tissue in the films, the covering material can be glued either by heat radiation, by contact heat or pressure or, in the case of some plastics, also by dissolving the covering material with suitable solvents.

In a manufacturing process according to Claim 2 or 3, in which a metal reinforcement is to be introduced, the heating of the reinforcement can be carried out in a simple manner by connecting it to a power source, so that it heats up uniformly by the flow of electrons and sinks into the plastic film, for example due to its own weight . In addition, the heated film can be pressed in or pressed in. The same applies to the production of a reinforced plastic film from a composite material consisting of film-reinforcement-film.

Finally, such a composite can also be produced in a membrane press, with all materials being brought above the flow temperature of the plastic material and then being able to be pressed together.

The manufacturing methods or armored foils according to the invention are described in detail with reference to the drawing figures 1 to 12 illustrates.

1, starting threads 1 are shown, the core 2, which consists, for example, of a glass fiber, being encased by the plastic material 3. The film 4 shown in FIG. 2, in which the reinforcing threads 1 run in the longitudinal direction parallel to one another, can be produced therefrom by a method according to the invention. The plastic sleeves 3 were pressed apart laterally during manufacture and have joined to form the closed film 4.

In Fig. 3, a fabric is shown, in which the warp thread 5, which in turn consists of a core 6 and a plastic jacket 7, is tightly tensioned and the weft thread 8, also consisting of core and jacket, loosely connects the warp threads 5. 4, in which the jacket material 7 has become a closed film 9. The cores of the warp threads 5 are straight, while the cores of the weft threads 8 are arranged in a wave shape. The restoring force in the direction of the weft threads 8 results from this waveform.

In Fig. 5 a fabric of covered threads with core and sheath is shown alternating with threads 11 made of pure sheath material. After processing, the film 12 according to FIG. 6 results, in which the tissue made of the core material is at a large distance from one another.

FIG. 7 shows schematically how two foils 13, 14 lying one above the other are welded in a gas-tight manner and form a cushion structure which are filled with a light gas 15. Due to the resulting buoyancy, the film is carried. The upper film 13 in turn has a reinforcement.

A device for producing the armored foils is shown in FIG. 8. The fabric 16 runs through the braking device 17. The Braking force is set by the brake shoe 18. The fabric then runs past the first softening station 19, which emits thermal radiation. If necessary, a solvent or a solvent could also be applied there to the surface of the fabric.

The fabric web then runs over a plurality of rollers 20 which press the shell material of the fabric together to form a closed film. Depending on the specified process parameters, several softening stations or rollers can be provided.

The finished film 21 is drawn through the calender with the help of the driver rollers 22.

9, a support fabric 25 is inserted between two finished films 23, 24 and then pressed under heat to form the finished film composite 26 (FIG. 10).

In Fig. 11, a hot support fabric 28 is placed over a finished sheet 27. As a result, the film material softens at the contact points and the fabric sinks into the liquefied plastic. This process can be mechanically supported if necessary.

In this way, the armored film 29 acc. Fig. 12.

Reference list

Starting thread core plastic sheathing film warp thread core plastic sheathing weft thread sheathing thread sheathing foil sheathing gas fabric braking device brake shoe softening station roller foil driving roller foil foil supporting fabric foil composite foil supporting fabric foil

Claims

claims 1. A method for the production of reinforced plastic films, characterized in that an at least partially plastic threads or plastic-coated threads (1) existing fabric is chemically and / or physically softened and is deformed by pressing, rolling, rolling or calendering in such a way that Connect adjacent threads with lateral expansion of the plastic jacket (3) in the later film level to form a closed film (4). 2. Process for the production of reinforced plastic foils, so that the reinforcement (28) in the form of threads or fabrics is heated above the softening point of the plastic and pressed or pressed into the foil in the heated state. 3. Process for the production of reinforced plastic films, characterized in that a composite material consisting of film (23), reinforcement (25), film (24) softens at least in the region of the mutually facing film sides and the films including the reinforcement (28) are glued or connected together. 4. According to one of the procedures. Claims 1 to 3 produced plastic film, so that the plastic-coated threads (1) or the reinforcement consist of metal, glass or quartz. 5. According to one of the procedures. Claim 1 manufactured plastic film, characterized in that the plastic (3) consists of a UV-resistant fluoropolymer. Plastic film according to one of claims 4 or 5, characterized in that the fluoropolymer contains light-absorbing or scattering ingredients such as titanium dioxide or pigments.