AT527158A1 - Process for the production of plastic strapping bands - Google Patents

Abstract

The invention relates to a method for producing plastic strapping bands. The method comprises the method steps of providing at least a first plastic material, subsequently melting the first plastic material, subsequently forming a film strand, subsequently dividing the film strand along a material transport direction into first band strands with first band strand widths and first band strand thicknesses by means of dividing devices and subsequently stretching in the material transport direction of the first band strands by means of a stretching device to form second band strands with second band strand widths and second band strand thicknesses.

Description

others.

Plastic strapping bands are mainly used to secure goods or to hold goods securely. The goods to be secured are wrapped around them using these strapping bands and the band ends are usually connected to one another, for example by welding. Plastic strapping bands have numerous advantages over strapping bands made of other materials, such as steel. Plastic strapping bands are easier and cheaper to produce, easier to handle, corrosion-resistant and

emission-free and also have a low CO2 footprint.

Thermoplastics or plastic materials are used to manufacture plastic strapping bands. The high tensile strengths required for the intended use are given to the plastic strapping bands by monoaxial stretching using so-called stretching machines. This type of stretching induces an orientation of the macromolecule chains in the stretching direction or longitudinal direction in the plastic strapping bands, whereby the high tensile strengths of the plastic materials are achieved in this direction. Particularly in the case of semi-crystalline, thermoplastic plastic materials,

This enables similarly high tensile strengths to be achieved as with steel.

The usual manufacturing methods for plastic strapping involve melting the thermoplastic materials, usually in the course of

extrusion, shaping, cooling and stretching.

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can be extruded, formed and stretched.

Alternatively, a manufacturing method is used in which a very wide strand is extruded in the form of a film, formed and then monoaxially stretched. The resulting stretched film is then cut lengthwise into individual strip strands and processed further. The resulting strip strands are usually rolled up on spools as so-called endless strands and only wrapped into ready-to-use wrappers at the place of use.

tapes are cut to the appropriate or required length.

The method of producing films, stretching them and then cutting them into individual strands has been known for a long time. This production method is summarized and described in DE 40 07 560 A1, for example. In principle, such cutting or dividing of monoaxially stretched films in the longitudinal or stretching direction can be accomplished without too much effort, since the films to be cut usually do not have a high tensile or tear strength in this direction. Cutting monoaxially stretched films also allows good control of the desired tape width.

ten.

However, this previously known process step of cutting or dividing a stretched film can also be problematic. For example, cutting stretched films inherently causes high levels of abrasion due to their solid consistency, and the respective cutting tools can therefore be subject to high levels of wear. In addition, cutting or dividing stretched films can lead to damage to the divided strip strands themselves. In particular, due to the low tear strength along the stretching direction, the monoaxially stretched plastic strands can split during dividing and/or the formation of notches on the strip strand edges. This can lead to an increased level of product

Furthermore, this previously known

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Strand thickness along the width of a film strand.

The aim of the present invention was to overcome the remaining disadvantages of the prior art and to provide a process by means of which plastic strapping bands can be produced in a highly reliable manner, as independently as possible of the plastic material used and without high wear of cutting devices and without high waste.

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

The process for producing plastic strapping includes the following:

following procedural steps in the specified sequence:

- Providing a first plastic material consisting of 70 wt.% to 100 wt.% thermoplastic, first polymer and 0 wt.% to 30 wt.% of a further component or several further components,

- subsequently melting the first plastic material by means of an extrusion device to form a first plastic melt,

- subsequently forming a film strand by feeding at least the first plastic melt in a material transport direction to a forming device, and cooling the first plastic material,

- subsequently dividing or cutting the film strand along the material transport direction into first strip strands with first strip strand widths and first strip strand thicknesses by means of dividing devices,

- subsequent stretching in the material transport direction of the first strip strands by means of a stretching device to form second strip strands with second strip strands-

wide and second strip thicknesses.

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synonymous with this.

As the first plastic material, in particular a plastic material consisting of 80 wt.% to 98 wt.% thermoplastic, first polymer and 2 wt.% to 20 wt.% of a further component or several further components can be provided. Regardless of the amount of the further component or components of the first plastic material, these further component(s) can be replaced, for example, by fillers, additives, plasticizers or also by one or more other polymer(s) than the first polymer.

be educated.

The targeted cooling of the film strand to a desired target temperature for the subsequent cutting step can only be carried out by means of the shaping device itself. For this purpose, the first plastic melt can be cooled, for example, by means of at least one temperature-controlled roller or roller with a temperature-controlled roller surface of the shaping device. For example, at least one roller of the shaping device can be subjected to a coolant. In addition, however, a separate cooling of the plastic melt before the film strand is formed and/or an additional, separate cooling of the film strand after the film strand has been formed can also take place by means of an additional cooling device, such as a water bath. A film strand thickness of the film strand can, for example, be adjusted as is known per se by passing the first plastic melt through a gap between

adjacent rollers can be specifically adjusted, whereby at least one of the

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Rolling mill, also known as calender or smoothing mill.

The film strand can be cut, for example, using knife blades, non-rotatable or round blades that can rotate along or against the material transport direction, or also using laser or water jet cutters.

cutting devices.

By cutting the film strand before stretching, the cutting or cutting process can be carried out very gently and with very little wear and tear. This is because the film strand is still at a high temperature and relatively soft at this point in the process. This relatively high temperature is important for the subsequent processing.

stretching step is also necessary.

A thickness of the film strand after forming or the first strip strand thickness after cutting can be set, for example, to 0.6 mm to 3.8 mm, preferably 0.8 mm to 2.8 mm. By stretching, the second strip strand thicknesses can be set to a value of 0.15 mm to 1.8 mm, preferably 0.2 mm to 1.4 mm. The second strip strand widths can be set to a value of 3 mm to 40 mm, in particular 4 mm to 36 mm, by cutting and subsequent stretching, whereby the second strip strand widths are mainly determined according to the respective intended

The intended use for the plastic strapping bands can be selected.

Surprisingly, in connection with the cutting before stretching, it has been shown that, despite the still soft consistency of the film strand, a very precise cutting of the film strand into the individual, first strip strands is possible using conventional cutting or slitting devices, and there are hardly any deviations in the respective, first strip strand widths. It has also been shown, just as surprisingly, that this procedure also produces second, stretched strip strands with very uniform

produce different strip widths and strip thicknesses after stretching

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che deformations of the plastic materials during stretching.

In addition, it has also been shown that cutting a film or film strand before stretching is more tolerant with regard to the plastic materials that can be used than cutting it after stretching, as in the prior art. In particular, a process involving cutting before stretching is less problematic with regard to the uniformity and quality of the plastic material(s) used, as will be explained in more detail below.

is purified.

Following the stretching process step, further process steps can optionally be carried out. As is well known, a stretched strip can be embossed, waxed or treated in some other way. Finally, the strips can of course be assembled. The resulting strips are usually rolled up on spools as so-called endless strips and only at the place of use are they made into ready-to-use strapping bands with the appropriate or required

tape length cut.

In a further development of the method, it can be provided that the film strand is cooled to a temperature of 75 °C to 135 °C for the cutting step.

Below the specified temperature range, some plastic materials may already experience increased wear of the cutting devices, especially cutting devices in the form of cutting tools. Above the specified temperature range, due to increased material flow of the plastic material, the first strip strands may, for example, stick together again, as well as the formation of first strip strands with inhomogeneous,

first strip widths and strip thicknesses especially in the edge areas

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become.

Furthermore, the method can provide for the forming of the film strand by means of a forming device which has rotatably mounted

rollers.

In particular, the shaping device can be formed by a so-called rolling mill, also referred to as a calender or smoothing machine. As already mentioned, the film strand can be shaped using such rollers, whereby a film strand thickness of the film strand can be specifically adjusted, for example, by passing the first plastic melt through a gap between adjacent rollers. At least one of the adjacent rollers can be arranged so as to be adjustable in order to change the film strand thickness. Shaping devices comprising rollers have proven to be particularly well suited to the present process for shaping film strands with a very uniform and even structure and very evenly designed.

treated surfaces of the top and bottom.

In this context, it may also be expedient if, during the process step of forming the film strand, at least one surface of the film strand is structured by means of at least one roller surface

is structured.

Such a surface structure on at least one surface can be particularly helpful when using the plastic strapping bands to form a strap. For example, such a surface structure can support or simplify the welding process that is usually carried out. In particular, such a surface structure can make a so-called friction welding process considerably easier or more efficient. For example, the at least one surface of the film strand can be provided with a microstructure,

in particular with a microstructure that is not visible to the naked eye in the

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become.

In a preferred embodiment of the method, it can be provided that at least some of the cutting devices for adjusting the first strip widths along the direction running parallel to the strip widths.

tion can be adjusted.

Such a process allows a simple but efficient setting of a desired first strip width of the unstretched strip strands, and in connection with the subsequent stretching also a targeted setting of the desired second strip widths of the second strip strands or the ultimately resulting plastic strapping bands. In particular, all existing cutting devices for setting the first strip widths can be adjusted along the direction running parallel to the strip widths. In addition, in connection with the adjustment along the strip widths, it can also be provided that at least some of the cutting devices are directed away from the film strand or the first strip strands.

be adjusted.

Furthermore, in connection with the adjustment of the cutting devices, it may also be useful that, following the stretching, actual values of the second strip widths are recorded by means of at least one sensor device and, based on these determined actual values, the cutting devices are adjusted with regard to the respective desired target values for the second strip widths along the direction running parallel to the strip widths for setting the first

Band widths can be adjusted.

This measure allows a simple and variable adjustment for each

desired strip widths of the first and second strip strands and thus provides

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mera must be formed.

In order to automate the adjustment of the cutting devices along the direction of the strip widths, it can be expedient if the recorded actual values of the second strip widths are transmitted from the sensor device to a control device and the cutting devices are automatically adjusted in the direction parallel to the strip widths by the control device for setting the first strip widths.

become.

This enables a high degree of automation of the process.

targetable.

Irrespective of this, a method variant can also be advantageous in which, following the stretching, actual values of the second strip strand thicknesses are recorded by means of at least one sensor device and that a film strand thickness of the film strand is adjusted with respect to the respective desired target values for the second strip strand thicknesses by means of the shaping device.

the.

This measure allows in particular a simple and variable setting of the desired strip thicknesses of the first and second strips. The at least one sensor device can in turn be formed by an optical sensor, in particular a camera. In this case, basically the same sensor device can be used which is also used to determine the second strip widths, or of course also a separate

sensor device.

Also in connection with the determination of the second strip thickness,

It should again be provided that the recorded actual values of the second strip strand

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thicknesses are transmitted from the sensor device to a control device and the film strand thickness is controlled by the forming device.

is set automatically using the control device. This measure also allows a highly automated process.

In a further preferred embodiment of the method, it can be provided that a second plastic material consisting of 90 wt.% to 100 wt.% of partially crystalline, thermoplastic, second polymer and 0 wt.% to 10 wt.% of a further component or several further components is also provided, which second plastic material is melted by means of a further extrusion device to form a second plastic melt, which second plastic melt is brought together with an upper side and/or a lower side of the first plastic melt before the film strand is formed so that the second plastic melt completely covers the upper side and/or the lower side of the first plastic melt, and that the film strand is formed by means of the forming device by jointly forming the first plastic material and the second plastic material so that a multi-layer film strand is formed with a base strand layer made of the first plastic material and at least one surface strand layer made of the second plastic material connected to an upper side or lower side of this base strand layer, wherein this multi-layer film strand is formed in such a way that it consists of 50 wt.% up to 90 wt.% of the first plastic material and 10 wt.% to 50 wt.% of the second plastic material.

This process can also be used to produce multilayer plastic strapping bands, whereby the properties of the first plastic material in the base strand layer and the properties of the second plastic material in the surface strand layer can complement each other synergistically. In particular, the multilayer film strand can be formed in such a way that it consists of 70 wt.% to 90 wt.% of the first plastic material and 10

% to 30 wt. % of the second plastic material. The process-

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Proper cutting before the stretching step is particularly advantageous when forming multilayer film or tape strands, since, in contrast to cutting after stretching, delamination tendencies can be prevented. As has been shown, in the case of forming a multilayer film strand or multilayer first and second tape strands, inferior first plastic material can also be used or provided as the first plastic material for the base strand layer. In particular, the at least one surface layer made of the second plastic material connected to the base strand layer after cutting appears to be particularly suitable during the mechanically very stressful and thus process-critical step of

Stretching to give the first tape strands sufficient stability.

When forming a multi-layer film strand, it can be provided, for example, that the first plastic material is provided with a proportion of 50% to 100% by weight of exclusively mechanically recycled plastic material. With such a process, the plastic strapping

tapes can be produced more sustainably and also more cost-effectively.

In addition to the exclusively mechanically recycled plastic material, the first plastic material can also comprise up to 50% by weight of non-recycled or chemically recycled plastic material. Preferably, the first plastic material can be provided with a proportion of 80% by weight to 100% by weight of exclusively mechanically recycled plastic material and additionally up to 20% by weight of non-recycled or chemically recycled plastic material. Regardless of the type of production or preparation or the type of provision of the components for the first plastic material, the first plastic material consists, as specified in the claims, of 70% by weight to 100% by weight of the thermoplastic, first polymer and 0% by weight to 30% by weight of the further component or several further components. The thermoplastic, first polymer can be formed, for example, by polyethylene terephthalate, polypropylene, polyethylene or polystyrene. In particular, the first

Plastic material, a plastic material must be provided which is completely

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consists exclusively of mechanically recycled plastic material. The second plastic material can be a non-recycled or chemically recycled plastic material, or a high-quality, mechanically recycled plastic material. The second plastic material also applies that, regardless of the amount of the additional component or components of the second plastic material, this or these additional component(s) can be supplemented, for example, by fillers, additives, plasticizers or by one or more other polymer(s) than the second, semi-crystalline polymer.

can be formed.

An exclusively mechanically recycled plastic material is understood to be a plastic material that has already been used or employed at least once and in which no chemical recycling, in particular no chemical reaction, was carried out in the course of recycling. As is known, chemical recycling can take place through chain scission or depolymerization of polymers down to monomers and subsequent re-polymerization. In particular, the first plastic material can be post-consumer

mer and/or post-industrial goods or plastic material.

A chemically recycled plastic material is understood to be a plastic material in which such chemical reactions were deliberately induced during the recycling process, in particular depolymerization and subsequent re-polymerization. A non-recycled plastic material is understood to be a freshly polymerized or manufactured plastic material that has not yet been used.

was, i.e. a new plastic material or new product.

Furthermore, when forming a multilayer film strand, it can be provided that the first plastic material is a plastic material with a melt mass flow rate (MFR) according to ISO 1133 of 2 g/10min to 35 g/10min, and that the second plastic material is a plastic material with a melt mass flow rate (MFR) according to ISO 1133 that is the same or higher than the first plastic material. This

Procedural management can in particular ensure a procedurally stable formulation of the

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multilayer film strand with homogeneous and regular or uniform formation of the layers. In particular, irregularities in

the formation of layers can be prevented.

In principle, the first, thermoplastic polymer and the second, semi-crystalline, thermoplastic polymer can each be formed by any polymers

be.

Preferably, in the case of forming a multilayer film strand, it can be provided that plastic materials of the same type are provided as the first plastic material and as the second plastic material. This measure makes it possible to produce a film strand with a stable and permanently uniform layer structure, as well as improved adhesion of the base strand layer and the surface strand layer(s) to one another. Plastic materials of the same type are understood to mean plastic materials that comprise the same type of thermoplastic polymer. In this embodiment, both the first and the second plastic materials can be thermoplastic polymers, for example a polyolefin, a polyester or a polyamide as the first and second polymers respectively.

grasp.

In particular, when forming a multilayer film strand, it can be provided that plastic materials are provided as the first plastic material and as the second plastic material, in which a chemical formula of the thermoplastic, first polymer corresponds to a chemical formula of the semi-crystalline thermoplastic, second polymer. This process can in particular further improve the adhesion of the surface strand layer(s) to the base strand layer during the formation of the multilayer film strand as well as in the first and second band strands or during the following process steps of cutting and stretching, but also subsequently when using the multilayer plastic strapping bands.

be further improved.

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It can be particularly useful when forming a multilayer film strand if plastic materials are provided as the first plastic material and as the second plastic material in which both the thermoplastic first polymer and the partially crystalline thermoplastic second polymer are formed from polypropylene. Plastic materials based on polypropylene have proven to be particularly suitable for forming the multilayer

Plastic strapping has proven to be effective.

When forming a multilayer film strand, it can also be provided that, during the process step of combining, the first plastic melt and the second plastic melt are combined in such a way that the second plastic melt completely covers an upper side and a lower side of the first plastic melt. This measure allows the multilayer film strand and the first and second band strands to be even better stabilized during processing, as well as the multilayer plastic strapping bands during use. This is probably because the low-quality, exclusively mechanically recycled plastic material, which accounts for at least 50% by weight of the first plastic material, is replaced on both the upper side and the lower side by a surface (strand) layer made of the second plastic material.

protects or is stabilized.

In the case of forming a multilayer film strand, the first plastic material provided can be, for example, a plastic material with a filler content of 2% by weight to 30% by weight. This can reduce the manufacturing costs of the multilayer plastic strapping bands in particular, since a plastic material with a high proportion of filler(s)

is generally cheaper to provide.

In particular, when forming a multilayer film strand, the first plastic material provided may be a plastic material containing 2% to 30% by weight of coloring filler(s). Such fillers may

as particularly cost-effective materials in the first plastic material

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Nevertheless, for example, the second tape strands in particular can be printed on a surface strand layer or the surface strand layers after stretching, since a surface strand layer acts as a cover layer against a base strand layer connected to it.

and thus a coloring of the base layer can be easily covered.

For a better understanding of the invention, it is explained in the following

Figures are explained in more detail. They show in a highly simplified, schematic representation:

Fig. 1 shows an example of process steps for melting plastic materials, combining plastic melts and

Forming of a film strand, in side view;

Fig. 2 shows an embodiment of a process step for cutting a film

enstranges, in side view and in plan view from above;

Fig. 3 shows an embodiment of a process step stretching of

Ribbon strands in side view and in top view;

Fig. 4 shows an embodiment for further process steps according to the

stretching of ribbon strands, in side view.

To begin with, it should be noted that in the various embodiments described, identical parts are provided with identical reference symbols or identical component designations, whereby the disclosures contained in the entire description can be transferred analogously to identical parts with identical reference symbols or identical component designations. The position information chosen in the description, such as top, bottom, side, etc., also refers to the figure directly described and shown, and these position

information must be transferred analogously to the new location in the event of a change in location.

The present method for producing plastic strapping bands initially comprises providing at least a first plastic material

as 1. This at least one first plastic material 1 consists of 70

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% by weight of thermoplastic, first polymer and 0 wt. % to 30 wt. % of a further component or several further components, and can in particular consist of 80 wt. % to 98 wt. % of thermoplastic, first polymer and 2 wt. % to 20 wt. % of a further component or several further components. Regardless of the amount of the further component or components of the first plastic material 1, the same can be formed, for example, by fillers, additives, plasticizers or also by one or more other polymer(s) than the first polymer.

be.

As shown schematically in Fig. 1, the at least one first plastic material 1 is melted by means of an extrusion device 2 to form a first plastic melt 3. In the embodiment shown in Fig. 1, a second plastic material 4 can also be provided, which second plastic material 4 can be melted by means of a further extrusion device 5 to form a second plastic melt 6. As the second plastic material 4, for example, a plastic material consisting of 90 wt. % to 100 wt. % partially crystalline, thermoplastic, second polymer and 0 wt. % to 10 wt. % of a further component or several further components can be provided. Regardless of the amount of the further component or components of the second plastic material 4, the same can be formed, for example, by fillers, additives, plasticizers or also by one or more other polymer(s) than the partially crystalline, second polymer. However, contrary to the embodiments shown in Fig. 1 and the following Figs. 2 to 4, the method can of course also be carried out with just the first plastic material 1 alone. The second plastic material 4 can be processed together with the first plastic material 1 to form a multi-layer plastic strapping band, as will be described in more detail below. If only the first plastic material 1 is provided and processed, a plastic strapping band with only one layer will of course result or be produced using the method.

be provided.

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If a second plastic material 4 is also provided and processed by means of the method, as is also described below with reference to the exemplary embodiments according to Figs. 1 to 4, the first plastic material 1 can, for example, be provided with a proportion of 50% by weight to 100% by weight of exclusively mechanically recycled plastic material. In addition to the exclusively mechanically recycled plastic material, the first plastic material 1 can also comprise up to 50% by weight of non-recycled or chemically recycled plastic material. Preferably, the first plastic material 1 can be provided with a proportion of 80% by weight to 100% by weight of exclusively mechanically recycled plastic material and additionally up to 20% by weight of non-recycled or chemically recycled plastic material. The thermoplastic, first polymer can be formed, for example, by polyethylene terephthalate, polypropylene, polyethylene or polystyrene. In particular, a plastic material which consists entirely of exclusively mechanically recycled plastic material can be provided as the first plastic material 1. The second plastic material 4 can be a non-recycled or chemically recycled plastic material, or a high-quality, mechanically

recycled plastic material should be provided.

If a second plastic material 4 is used, a plastic material with a melt mass flow rate (MFR) according to ISO 1133 of 2 g/10min to 35 g/10min can be provided as the first plastic material 1, and then a plastic material with a melt mass flow rate (MFR) that is the same or higher than the first plastic material can be provided as the second plastic material 4.

according to ISO 1133.

Preferably, in the case of processing a second plastic material 4, it can be provided that plastic materials of the same type are provided as the first plastic material 1 and as the second plastic material 4. In particular, in the case of an intended additional processing of the second plastic material 4, the first plastic material 1 and the second plastic material

4 Plastic materials are provided in which a chemical sum-

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formula of the thermoplastic, first polymer corresponds to a chemical formula of the semi-crystalline thermoplastic, second polymer. In particular, plastic materials can then be provided as the first plastic material 1 and as the second plastic material 4, in which both the thermoplastic, first polymer and the semi-crystalline, thermoplastic,

second polymer is formed by polypropylene.

In the case of additional processing of the second plastic material 4, a plastic material with a content of 2 wt.% to 30 wt.% of fillers can be provided as the first plastic material 1. In this case, a plastic material with a content of 2 wt.% to 30 wt.% of coloring filler(s) can also be provided as the first plastic material 1.

become.

Regardless of whether only the first plastic material 1 or also the second plastic material 4 is processed by means of the method, a film strand 7 is subsequently formed, as can be seen from Fig. 1. This is done by feeding at least the first plastic melt 3 in a material transport direction 8 to a shaping device 9. If only the first plastic material 1 is processed, this first plastic material 1 is formed into the film strand 7 by means of the shaping device 9. According to the embodiment shown in Fig. 1, the shaping device 9 can also be fed together with the first plastic material 1, but also the second plastic material 4 shown here, so that both plastic materials

materials 1, 4 of the film strand 7 are formed.

In this case, the procedure can be such that the second plastic melt 6 is brought together with an upper side 10 and/or a lower side 11 of the first plastic melt 3 before the film strand 7 is formed, so that the second plastic melt 6 completely covers the upper side 10 and/or the lower side 11 of the first plastic melt 3. In particular, it can also be provided that in the course of the process step of bringing together the first

Plastic melt 3 and the second plastic melt 6 are combined in such a way

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that the second plastic melt 6 completely covers the top 10 and the bottom 11 of the first plastic melt 3, as is the case with the

embodiment according to Fig. 1 is also shown.

If the first plastic material 1 and the second plastic material 4 are to be formed into a multilayer film strand 7, the first plastic melt 3 and the second plastic melt 6 can be combined using several methods known per se. For example, the two plastic melts 3, 6 can be combined using a so-called coextrusion box 12, also referred to as a feed block, as roughly schematically illustrated in Fig. 1, and after being combined, they can be output via a film extrusion tool 13 with a slot die and fed to the shaping device 9. As an alternative to the embodiment outlined in Fig. 1, other methods known per se for combining the plastic melts 3, 6 are of course also conceivable, such as using a so-called coextrusion tool or multilayer dies, the use of

several extrusion tools, each with one nozzle, and so on.

Subsequently, according to the embodiment shown in Fig. 1, the film strand 7 can be formed by means of the forming device 9 by jointly forming the first plastic material 1 and the second plastic material 4.

be formed.

As a result, as shown in Fig. 1, a multilayer film strand 7 can be formed with a base strand layer 14 made of the first plastic material 1 and at least one surface strand layer 15 made of the second plastic material 4 connected to an upper side 15 or lower side 16 of this base strand layer 14. In the embodiment shown in Fig. 1, as shown, it can be provided that a three-layer film strand 7 is formed with a base strand layer 14 made of the first plastic material 1 and surface strand layers 17 made of the second plastic material 4 connected to an upper side 15 and lower side 16 of this base strand layer 14. Such a multilayer film strand 7 can be formed, for example, in such a way that

that it consists of 50 wt.% to 90 wt.% of the first plastic material 1 and 10

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Wt. % to 50 wt. % of the second plastic material 4, in particular 70 wt. % to 90 wt. % of the first plastic material 1 and 10 wt. % to 30

wt.% of the second plastic material 4.

As is further illustrated in Fig. 1, the film strand 7 can be formed by means of the shaping device 9, which comprises rotatably mounted rollers 18, 19, 20, 21. The shaping device 9 can therefore be formed, as is known per se, by a rolling mill, also referred to as a calender or smoothing machine, as is also shown in the embodiment shown in Fig. 1. In this case, a film strand thickness 22 of the film strand 7 can be specifically adjusted, for example, as is known per se by passing the first plastic melt 3 and optionally also the second plastic melt 6, as shown in the embodiment, through a gap 23 between adjacent rollers 19, 20. For this purpose, at least one of the adjacent rollers 19, 20 can be adjustable to change the film strand thickness 22. A thickness of the film strand 7 after forming or the film strand thickness 22 illustrated in Fig. 1 can be, for example, 0.6 mm to 3.8 mm,

preferably 0.8 mm to 2.8 mm.

In addition, at least the first plastic material 1 is cooled, and in the embodiment shown in Fig. 1 the second plastic material 4 is also cooled, for the subsequent process step of cutting the film strand 7 shown in Fig. 2. The cooling of the film strand 7 to a desired target temperature for the subsequent cutting step can only be carried out by means of the shaping device 9 itself. For this purpose, the first plastic melt 3 and possibly also the second plastic melt 6 can be cooled, for example, by means of at least one temperature-controlled roller 18, 21 or roller with a temperature-controlled roller surface of the shaping device 9. For example, at least one roller 18, 21 of the shaping device can be subjected to a coolant. Additionally and/or alternatively, the plastic

melt(s) 3, 6 before forming the film strand 7 and/or an additional

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The film strand 7 can be cooled separately after the film strand 7 has been formed by means of an additional cooling device, such as a water bath, not shown in Fig. 1. The film strand 7 can preferably be cooled to a temperature of 75 °C to 135 °C, in particular 80 °C to 130 °C, for the subsequent process step of cutting.

In addition, during the process step of forming the film strand 7, at least one surface 24 of the film strand 7 can be structured by means of at least one structured roller surface 25. For example, the at least one surface 24 of the film strand 7 can be provided with a microstructure, in particular with a microstructure that is not visible to the naked eye in the sense of a matting. Alternatively, it can also be advantageous for certain applications if the surfaces 24 of the film strand 7 are designed to be very smooth, i.e. by means of at least one roller surface.

surfaces can even be smoothed out.

In Fig. 2, the subsequent process step of cutting the film strand 7 is illustrated, wherein in Fig. 2, the same reference numbers are used for the same parts/elements.

chen as in the previous Fig. 1. To avoid unnecessary repetition, reference is made to the detailed description in the previous

referred to or referred to in Fig. 1.

As can be seen from Fig. 2, the film strand 7 is divided or cut along the material transport direction 8 into first strip strands 26 with first strip strand widths 27 and first strip strand thicknesses 28 by means of cutting devices 29. The film strand 7 can be divided, for example, by means of knife blades, non-rotatable or round blades that can be rotated along or against the material transport direction, or by means of cutting devices 29 designed as lasers or water jets. The number of cutting devices 29 or strip strands 26 are of course only examples in the embodiment according to Fig. 2, and the respective number of cutting devices 29 or strip strands 26 can of course be varied. In addition to the cutting devices 29 shown in Fig. 2, if necessary or required,

also wishes in the edge areas of the film strand 7 or the outer

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Further cutting or slicing devices may be provided for the strip strands 26 in order to trim the edges of the outer strip strands 26 or to make them as even as possible

to design.

The method can further provide for at least some of the cutting devices 29 to be adjusted for setting the first strip widths 27 along a direction 30 running parallel to the strip widths 27, as is illustrated in Fig. 2 by the corresponding double arrows. With this measure, in particular the first strip widths 27 can be varied or adjusted as required or desired. For this purpose, the cutting devices 29 can, for example, be adjustably mounted or held on a holding strip 31 aligned parallel to the direction 30 of the strip widths 27, as shown schematically in Fig. 2. In particular, all existing cutting devices 29 for setting the first strip widths 27 can be adjusted along the direction 30 running parallel to the strip widths 27. In addition, in connection with the adjustment along the direction 30 of the strip widths 27, it can also be provided that at least some of the cutting devices 29 are separated from the film strip 7 or the first

band strands 26 can be adjusted.

Following the process step of cutting, as illustrated in Fig. 3, the first strip strands 26 are stretched in the material transport direction 8 by means of a stretching device 32 to form second strip strands 33 with second strip strand widths 34 and second strip strand thicknesses 35. In Fig. 3, the same reference numerals or component designations are used for the same parts as in the previous Figs. 1 and 2. To avoid unnecessary repetition, reference is made to the detailed description in

the preceding Figs. 1 and 2 are mentioned or referred to.

As is known per se, the stretching or drawing device 32 can be formed by a so-called stretching device, in which the first strip strands 26 are drawn into the second strip strands 33 in the transport direction 8 by means of successively faster rotating stretching or drawing devices 36, 37.

or flat. This ensures the desired preferred orientation

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of the macromolecular chains of the plastic material 1, or in the case of multilayered strip strands 26, 33 of the plastic materials 1, 4. Depending on the plastic material(s) 1, 4 used, the strip strands 26, 33 can be stretched with stretching ratios of 1:4 to 1:20. As is known per se, at least one tempering device can also be arranged upstream of the stretching device 32 or, if appropriate, between the pulling devices 36, 37 of the stretching device 32 or the stretching device in order to allow targeted tempering of the plastic material 1 or the plastic materials 1, 4 for the stretching process. Such tempering devices, such as water baths, cooling or heating air, or infrared radiators, are basically known from the prior art.

known and are not shown in detail in Fig. 3.

The stretching or elongation of the first strip strands 26 to form the second strip strands 33 is of course accompanied by a deformation, in particular by a reduction in cross-section, so that the second strip strand widths 34 and thicknesses 35 are smaller than the first strip strand widths 27 and thicknesses 28, as can also be seen from Fig. 3. By stretching, the second strip strand thicknesses 35 can be set, for example, to a value of 0.15 mm to 1.8 mm, preferably 0.2 mm to 1.4 mm. The second strip strand widths 34 can be set to a value of 3 mm to 40 mm, in particular 4 mm to 36 mm, by cutting and then stretching, with the second strip strand widths 34 being predominantly determined according to the intended use.

purpose for which plastic strapping bands can be selected.

As can best be seen by looking at Fig. 2 and Fig. 3 together, the method can provide that following the stretching, actual values of the second strip widths 34 are recorded by means of at least one sensor device 38 and based on these determined actual values, the cutting devices 29 are adjusted with regard to the respective desired target values for the second strip widths 34 along the direction 30 running parallel to the strip widths 34 for setting the first strip widths 27. The sensor device 38 can be an optical sensor device, in particular

especially by a camera.

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As can also best be seen by looking at Fig. 2 and Fig. 3 together, it can also be provided that the recorded actual values of the second strip widths 34 are transmitted from the sensor device 38 to a control device 39 and the cutting devices 29 are automatically adjusted in the direction 30 running parallel to the strip widths 27, 34 by the control device 39 to adjust the first strip widths 27. A signal connection between the sensor device 38, Fig. 3, and the cutting devices 29, Fig. 2, with the control device 39 is indicated in Figs. 2 and 3 by the dashed lines.

indicates.

As can best be seen by looking at Fig. 1 together with Fig. 3, in the method, following the stretching, actual values of the second strip strand thicknesses 35 can be recorded by means of at least one sensor device 40 and by means of the shaping device 9, one or the film strand thickness 22 of the film strand 7, and thus also the first strip strand widths 27 of the first strip strands 26 before stretching, can be adjusted with regard to the respective desired target values for the second strip strand thicknesses 35. The at least one sensor device 40 for determining the actual values of the second strip strand thicknesses 35 can in turn be formed by an optical sensor, in particular a camera. In this case, basically the same sensor device 38 can be used which is also used to determine the second strip strand widths 34, or of course also a separate sensor device 40, such as

This is illustrated in Fig. 3.

In connection with the recording of the actual values of the second strip strand thicknesses 35, it can also be provided that these recorded actual values of the second strip strand thicknesses 35 are transmitted from the sensor device 40 to a control device 39 and the film strand thickness 22 is set in an automated controlled manner by controlling the shaping device 9 by means of the control device 39. The signal connections of the sensor device 40 and the shaping device 9 for controlling

ing device 39 are indicated in Fig. 1 and Fig. 3 by dashed lines.

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In Fig. 4, further possible steps of the process following stretching are illustrated. In Fig. 4, the same reference symbols or component designations are used for the same parts as in the previous Figs. 1 to 3. In order to avoid unnecessary repetition, reference is made to the detailed description in the previous Figs. 1 to 3.

taken.

For example, it can be provided that the second strip strands 33 or one or both of their surfaces are subjected to a surface treatment by means of one or more surface treatment devices 41. A corresponding surface treatment can, for example, comprise coating the surface(s), for example with a wax or another coating agent. However, a surface treatment can also, for example, comprise irradiation or plasma treatment of the surface(s) of the second strip strands 33

include.

Furthermore, one surface or both surfaces of the second strip strands 33 can be embossed, for example by means of an embossing device 42. This may be in addition to the already mentioned structuring by means of the

forming device 9.

Finally, the second band strands 33 can be assembled, as also illustrated in Fig. 4, for example wound onto the winding device 43 shown in Fig. 4, often also referred to as a spooler, and thus prepared for

be prepared for transport.

Finally, for the sake of completeness, it should be mentioned once again that the method shown in Figs. 1 to 4, contrary to the embodiment shown here with multi-layer, in particular three-layer film strand 7, first tape strands 26 and second tape strands 33, can of course also be used with only single-layer film strand 7, and accordingly also single-layer first and second tape strands 26, 33, which each consist only of the first plastic material.

rial 1 can be carried out.

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The embodiments show possible variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated variants of the same, but rather various combinations of the individual variants with each other are also possible and this possibility of variation due to the teaching on technical action by means of objective invention in the skill of the person active in this technical field

specialist.

The scope of protection is determined by the claims. However, the description and the drawings are to be used to interpret the claims. Individual features or combinations of features from the different embodiments shown and described can represent independent inventive solutions in themselves. The features associated with the independent inventive solutions

The underlying task can be found in the description.

All information on value ranges in the description in question is to be understood as including any range and all subranges thereof, e.g. the information 1 to 10 is to be understood as including all subranges starting from the lower limit 1 and the upper limit 10, i.e. all subranges start with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

For the sake of clarity, it should be noted that for a better understanding of the structure, some elements are not to scale and/or enlarged.

and/or reduced in size.

27137 A2023/87683-AT

27

list of reference symbols

Plastic material Extrusion device Plastic melt Plastic material Extrusion device Plastic melt Film strand Material transport direction Forming device Top

Bottom Coextrusion box Film extrusion tool Base strand layer Top

bottom surface strand layer roller

roller

roller

roller

film strand thickness

gap

Surface Roll surface Strip strip width Strip strip thickness Cutting device

Direction

31 32 33 34 35 36 37 38 39 40 41

42 43

Holding strips Stretching device Strip strip Strip strip width Strip strip thickness Pulling device Pulling device Sensor device Control device Sensor device Surface treatment device Embossing device

winding device

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Claims (10)

patent claims 1. Process for producing plastic strapping bands, comprising the following process steps, - Providing at least a first plastic material (1) consisting of 70 wt.% to 100 wt.% thermoplastic, first polymer and 0 wt.% to 30 wt.% of a further component or several further components, - subsequently melting the first plastic material (1) by means of an extrusion device (2) to form a first plastic melt (3), - subsequently forming a film strand (7) by feeding at least the first plastic melt (3) in a material transport direction (8) to a forming device (9), and cooling the first plastic material (1), - subsequently dividing the film strand (7) along the material transport direction (8) into first strip strands (26) with first strip strand widths (27) and first strip strand thicknesses (28) by means of dividing devices (29), - subsequently stretching in the material transport direction (8) of the first strip strands (26) by means of a stretching device (32) to form second strip strands (33) with second strip widths (34) and second strip thicknesses (35). 2. Method according to claim 1, characterized in that the film strand (7) is cooled to a temperature of 75 °C to 135 °C for the cutting step. 3. Method according to claim 1 or 2, characterized in that the forming of the film strand (7) by means of the forming device (9), which rotatably mounted rollers (18, 19, 20, 21). 4. Method according to claim 3, characterized in that in the course of the method step of forming the film strand (7), at least one surface (24) of the film strand (7) is structured by means of at least one structured roller surface (25). A2023/87683-AT 5. Method according to one of the preceding claims, characterized in that at least some of the cutting devices (29) for adjusting the first strip widths (27) are arranged along a line parallel to the strip widths (27, 34) running direction (30). 6. Method according to claim 5, characterized in that following the stretching, actual values of the second strip strand widths (34) are detected by means of at least one sensor device (38) and based on these determined actual values, the cutting devices (29) are adjusted with respect to respective desired target values for the second strip strand widths (34) along the direction (30) running parallel to the strip strand widths (27, 34) for setting the first strip widths (27) can be adjusted. 7. Method according to claim 6, characterized in that the detected actual values of the second strip widths (34) are transmitted from the sensor device (38) to a control device (39) and the cutting devices (29) are controlled by the control device (39) along the direction (30) running parallel to the strip widths (27, 34) for setting the first strip widths. strand widths (27) can be adjusted automatically. 8. Method according to one of the preceding claims, characterized in that following the stretching, actual values of the second strip strand thicknesses (35) are detected by means of at least one sensor device (40) and that by means of the shaping device (9) a film strand thickness (22) of the film strand (7) is adjusted with respect to respectively desired target values for the second strip thicknesses (35) can be adjusted. 9. Method according to claim 8, characterized in that the detected actual values of the second strip thicknesses (35) from the sensor device (40) to a control device (39) and the film strand thickness (22) by controlling the forming device (9) by means of the control device direction (39) is adjusted in an automated controlled manner. A2023/87683-AT 10. Method according to one of the preceding claims, characterized in that a second plastic material (4) consisting of 90 wt. % to 100 wt. % of partially crystalline, thermoplastic, second polymer and 0 wt. % to 10 wt. % of a further component or several further components is also provided, which second plastic material (4) is melted by means of a further extrusion device (5) to form a second plastic melt (6), which second plastic melt (6) is brought together with an upper side (10) and/or a lower side (11) of the first plastic melt (3) before the film strand (7) is formed so that the second plastic melt (6) completely covers the upper side (10) and/or the lower side (11) of the first plastic melt (3), and that the film strand (7) is formed by means of the forming device (9) by jointly forming the first plastic material (1) and the second plastic material (4) so that a multilayer film strand (7) with a Base strand layer (12) made of the first plastic material (1) and at least one surface strand layer (15) connected to a top side (13) or bottom side (14) of this base strand layer (12) made of the second plastic material (4), wherein this multilayer film strand (7) is formed such that it consists of 50 wt.% to 90 wt.% of the first plastic material (1) and 10 wt.% to 50 wt.% of the second plastic material (4). A2023/87683-AT