Method and apparatus for producing flexible mesh composite material

Abstract

In order to produce a flexible mesh composite material (2) from a mesh substrate (3) and a mesh nonwoven material (4), discrete particles (7) are applied to the substrate (3) or the nonwoven material (4) by applying the particles (7) to a heated release surface (6) and softening them thereon and then transferring them from the release surface (6) to a surface (3a, 4a) of the substrate (3) or the nonwoven material (4). Optionally, the particles (7) are cooled and the substrate (3) and the non-woven fabric material (4) are bonded together, the surface (3a, 4a) of the substrate (3) or of the non-woven fabric material (4) on which the particles (7) adhere faces the surface (4a, 3a) of the substrate (3) or of the substrate (3), and then the particles (7) are optionally heated and the substrate (3) and the non-woven fabric material (4) are pressed together, therefore, the particles (7) connect the opposite surfaces (3a, 4a) of the base material (3) and the non-woven fabric material (4) together.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for producing a flexible net-shaped composite material according to the preamble of claim 1.

[0002] Furthermore, the present invention relates to an apparatus for producing a flexible net-shaped composite material according to the preamble of claim 17.

[0003] Finally, the present invention also relates to a flexible net-shaped composite material and a bag produced therefrom. BACKGROUND

[0004] The document EP 3 463 805 B1 describes a slip-resistant flexible material and methods of making and using the same. In this method, discrete thermoplastic particles heated to a tacky state are applied to the surface of a thermoplastic flexible carrier, which can be used as a slip-resistant flexible packaging material. Also disclosed are slip-resistant flexible packaging bags having a rough protrusion on their outer surface, and methods of making and using the same. If such bags are stacked on top of each other, the rough protrusions prevent them from sliding relative to each other, even though the material of the bags is not actually slip-resistant, because the protrusions interlock. It should also be noted that these protrusions provide an effective slip-resistant mechanical interlock with a fibrous interposition material, such as a nonwoven cloth, placed between two bags, for example. The nonwoven cloth can be lifted vertically from the rough surface. Furthermore, it is described in this document that the bags can be composed of a film and / or a woven cloth and / or a nonwoven cloth. Figure 12a of EP 3 463 805 B1 shows a tubular web made of a plastic film, in which rough protrusions are attached to one surface, a nonwoven strip is fixed to the opposite surface, the fibers of the nonwoven cloth are encapsulated and fixed to the film by a hot-melt adhesive sprayed by fibers or by extrusion lamination, and the sandwich structure made of film / melt / nonwoven is pressed between a pair of metal rollers.

[0005] The disadvantage of the film-nonwoven composite material produced in this way is that the mechanical properties of the nonwoven cloth are altered by the hot-melt adhesive or the extruded polyolefin polymer, which encapsulates the fibers of the nonwoven cloth and then presses against the film. As a result, the hot-melt adhesive or the extruded polyolefin polymer penetrates the nonwoven cloth up to its surface facing away from the film, thereby hardening and impairing the mechanical interlock with the rough surface of the film. As mentioned above, the type of fixing the nonwoven cloth to the film also involves a high material consumption of hot-melt adhesive or polyolefin polymer, which is unnecessary for the required mechanical interlock function of the nonwoven cloth. Furthermore, the use of hot-melt adhesive is disadvantageous because hot-melt adhesive is expensive and hinders the recycling of the articles produced from the film-nonwoven composite material.

[0006] A method for producing a thermoplastic film web for further processing into bags having a perforated area, which is covered with a strip of nonwoven fabric, is known from DE 40 33 499 A1. The strip of nonwoven fabric is attached to the film web by using an adhesive, the film web, the strip of nonwoven fabric and the adhesive being made of the same thermoplastic material. This method solves the problem that plastic bags coated with an adhesive cannot be recycled or can only be recycled for low-quality applications. During the production of the bags, a molten adhesive is applied along the edge area of the strip of nonwoven fabric between the strip of nonwoven fabric and the film web, and a bonding pressure is applied on the strip of nonwoven fabric, the adhesive and the film web, so that the thermoplastic material of the adhesive at least partially penetrates into the strip of nonwoven fabric and connects the strip of nonwoven fabric with the film web, the thermoplastic material hardening. The method described in DE 40 33 499 A1 has the disadvantage described above that the penetration of the plastic material into the nonwoven fabric partially or completely impairs its mechanical interlocking with the rough surface of the adjacent bags. Furthermore, the attachment of the strip of nonwoven fabric only occurs at its edges, so that the nonwoven fabric can move freely between its edges due to its elastic properties, so that it is not suitable for preventing the bags stacked together from slipping. This problem is not solved in DE 40 33 499 A1, because in the bags disclosed there, the strip of nonwoven fabric is only used to cover the perforations in the bag body made of the film web. For this reason alone, it is not possible to attach the strip of nonwoven fabric over the entire surface of the film web by applying a molten adhesive and subsequently applying a bonding pressure, because the perforations in the film web would thus be closed.

[0007] A method for producing bags comprising a plastic nonwoven fabric material is known from document WO 2011 / 018318 A1. The method comprises providing at least two flat web materials, a first layer made of a plastic nonwoven fabric material and a second layer made of a plastic coating; forming a tube from the flat web materials by overlapping and connecting edge side areas of the flat web materials to each other to form an overlap, the plastic coating facing outwards and the layer of plastic nonwoven fabric material facing inwards after the tube has been formed; dividing the tube into tube sections; and integrally forming a bottom at at least one end of the tube sections. Before the tube is divided into tube sections, the at least two flat web materials or the tube made thereof are perforated. This is necessary because the layer of plastic nonwoven fabric material is practically air-permeable, which is important when filling the bags, so that air can escape from the inside of the bags, but the plastic coating prevents air from escaping. However, the disadvantage associated with perforating the flat web material comprising the layer of plastic nonwoven fabric material and the plastic coating is that the layer of plastic nonwoven fabric material is also perforated thereby. The nonwoven fabric layer forms a labyrinth from its multitude of fibres, which practically allows air to pass through, but retains the filling material contained in the bag, which is usually in granular or powder form, from leaking out of the bag. If the nonwoven fabric layer is now perforated, the perforations form straight-line passages through the entire flat web material, so that the nonwoven fabric layer can no longer prevent the filling material from passing through the flat web material forming the bag wall. SUMMARY

[0008] It is an object of the present invention to propose a method of producing a flexible web composite material which overcomes or at least mitigates the above-mentioned drawbacks of the prior art. In one aspect of the invention, the flexible web composite material produced according to the invention is used for manufacturing a bag.

[0009] The object is achieved by the method of producing a flexible web composite material having the features of claim 1, the apparatus having the features of claim 17 and the composite material having the features of claim 20. Advantageous embodiments of the invention are set out in the dependent claims, the description and the drawings.

[0010] The method of producing a flexible web composite material according to the invention comprises: providing a web substrate comprising at least in part a first thermoplastic polymer; providing a web nonwoven material comprising at least in part a second thermoplastic polymer; applying discrete particles containing a third thermoplastic polymer to the web substrate or the web nonwoven material by providing a release surface; providing and arranging a plurality of the discrete particles on the release surface, the release surface having a temperature above the softening temperature of the third thermoplastic polymer; heating the particles arranged on the release surface to above the softening temperature of the third thermoplastic polymer; bringing the surface of the substrate or the nonwoven material into contact with the release surface and the softened particles arranged thereon, so that the particles adhere to the surface of the substrate or the nonwoven material; subsequently peeling the surface of the substrate or the nonwoven material with the adhered particles from the release surface; and optionally cooling the particles adhered to the surface of the substrate or the nonwoven material to below the softening temperature of the third thermoplastic polymer, joining the substrate and the nonwoven material together, the surface of the substrate or the nonwoven material with the adhered particles facing the surface of the nonwoven material or the substrate; pressing the substrate and the nonwoven material together, whereby the particles interconnect the mutually facing surfaces of the substrate and the nonwoven material, optionally heating the particles adhered to the surface of the substrate or the nonwoven material to above the softening temperature of the third thermoplastic polymer before pressing the substrate and the nonwoven material together; and optionally cooling the composite material produced from the substrate and the nonwoven material.

[0011] By this method, the substrate and the nonwoven material are interconnected by a plurality of discrete connection points made of particles containing a third thermoplastic polymer, which connection points extend substantially over the entire connection surface between the substrate and the nonwoven material, while being distributed as evenly as possible, resulting in an overall effect of a "full-surface" connection with uniform connection properties. In contrast to the connection of a substrate and a nonwoven by extrusion lamination or gluing known from the prior art, according to the present invention, the cavities in the nonwoven material remain substantially intact, so that they will be retained both for the positive connection to the material rendered slip-resistant by the application of the plastic particles and for the retention of the powdery or granular material by the labyrinthine channels formed by the cavities in the nonwoven.

[0012] According to the method of the present invention, expensive equipment such as extruders or hot-melt melting equipment can advantageously be omitted. Furthermore, the material consumption of the adhesive, i.e. the particles, is significantly lower than when a substrate is connected to a nonwoven by means of hot-melt adhesives or extruded polymers. A further positive effect of the present invention is that the substrate and the nonwoven can be recycled in combination.

[0013] In a further development of the present invention, after the substrate and the nonwoven material have been pressed together, discrete particles containing a fourth thermoplastic polymer are applied to the surface of the substrate opposite the nonwoven material by providing a release surface, providing and arranging a plurality of the discrete particles on the release surface, the release surface having a temperature above the softening temperature of the fourth thermoplastic polymer, heating the particles arranged on the release surface to above the softening temperature of the fourth thermoplastic polymer, bringing the surface of the substrate opposite the nonwoven material into contact with the release surface and the softened particles arranged thereon, so that the particles adhere to the surface of the substrate, subsequently peeling the surface of the substrate with the particles adhering thereto from the release surface, and optionally cooling the particles adhering to the surface of the substrate to below the softening temperature of the fourth thermoplastic polymer. In this context, "cooling" is generally understood as active cooling using cooling equipment or passive cooling, for example allowing cooling in ambient air.

[0014] The flexible web composite produced in this way thus meets all the requirements for processing into bags, which feature a high degree of slip resistance when stacked on top of one another, since the particles applied to the surface of the substrate forming the outer surface of the bag positively engage the cavities in the nonwoven material of the composite, which is arranged on the outer surface of the bag opposite the outer surface with the particles. Since the nonwoven material is connected to the substrate over the entire connection surface by means of a multiplicity of connection points, when a stack of bags stacked on top of one another is tilted, in each case the nonwoven side of one of the bags is facing the side with the particles on the substrate of the adjacent bag, which does not even come loose when shear forces occur. This means that a tilting angle of typically 35° or more without the bags slipping is possible, the stack of bags will first topple over. Thus, for the bags stacked on top of one another, the stretch film, shrink film or cover or other means for securing the load can be omitted.

[0015] If the substrate or the composite made of the substrate and the nonwoven material is turned over before the particles containing the fourth thermoplastic polymer are applied to the surface of the substrate opposite the nonwoven material and this surface of the substrate faces the release surface, the release surface is also used for applying particles containing the third thermoplastic polymer, the apparatus for producing a web composite according to the method of the application can be significantly simplified, since a single release surface is used for applying particles on both sides of the composite.

[0016] The web substrate can be tubular for manufacturing bags, which are optionally provided with side folds depending on the type of bag to be produced from the composite.

[0017] In a preferred embodiment of the application, the substrate comprises at least one layer made of a plastic tape fabric, preferably made of PP, HDPE or PET. The plastic tape fabric can have a coating, which is optionally printed, or a plastic film, which is laminated and serves as a carrier for printing, for example, or as a barrier layer, for example as a moisture barrier.

[0018] In an alternative embodiment of the application, the substrate is a single-layer or multi-layer plastic film, which is optionally printed, preferably made of PP, LLDPE, LDPE, HDPE or PET.

[0019] For certain applications, the composite produced according to the present application must be air permeable, for example, if a valve bag is produced from such a composite, the valve bag is filled with a powder or granulate filling material by means of an air flow, wherein the air must be able to escape from the bag. For such applications, it is conceivable to perforate the substrate before it is combined with the nonwoven material. In this case, it is of utmost importance that only the substrate is perforated and not the nonwoven material, because otherwise the nonwoven material would lose its holding function for the filling material, for example very fine-grained / fine-powdered cement.

[0020] The nonwoven material is preferably a spunbond nonwoven or a carded nonwoven or a hydroentangled material or a meltblown material or a spunbond material or a composite made of the aforementioned materials.

[0021] It has proven useful if the first and / or the second thermoplastic polymer is selected from the group consisting of PET, PP, PE or a copolymer or terpolymer containing two or three of the following monomers: ethylene, propylene, vinyl acetate, alkyl acrylate, maleic anhydride, alpha-olefins. Thus, the first and the second thermoplastic polymer can be selected from the same material or from different materials.

[0022] The third and / or the fourth thermoplastic polymer is preferably selected from the group consisting of PET, PP, PE or a copolymer or terpolymer containing two or three of the following monomers: ethylene, propylene, vinyl acetate, alkyl acrylate, maleic anhydride, alpha-olefins. Thus, the third and the fourth thermoplastic polymer can be selected from the same material or from different materials.

[0023] In a preferred embodiment of the present application, the particles containing the third thermoplastic polymer have an average particle size of less than or equal to 1000 pm. In another preferred embodiment of the present application, the particles containing the fourth thermoplastic polymer have an average particle size of 80 to 800 pm, preferably 100 to 500 pm, the particle size being as uniform as possible, in particular with a particle size difference of less than 3 times, which is particularly preferred for the most uniform connection and slip resistance. The particles containing the fourth thermoplastic polymer are selected by sieving with a sieve having a defined mesh size, which ensures a good uniform particle size.

[0024] According to the present application, it is preferred that the substrate has a basis weight of 1 g to 20 g / m 2 , preferably 3 g to 5 g / m 2The particles between the base material and / or the non-woven material. These basis weights are far below the basis weight of the extrusion bond, but still ensure sufficient bond strength, wherein the bond strength can be adjusted by choosing the appropriate basis weight, such that the non-woven material does not separate from the base material due to the action of shear forces, but can be pulled off the base material by, for example, manually applying a force perpendicular to the bond surface. This also ensures that the particles do not clog the cavities in the non-woven material, if the basis weight of the particles is in this specified range.

[0025] According to the present application, it is envisaged that the particles are adjusted to a temperature above their softening temperature but below their melting temperature, when the particles are bonded to the base material or the non-woven material. As a result, the particles embed in the base material or the non-woven material, without the non-woven material or its fibers being substantially damaged, but with good adhesive properties (by active bonding) between the base material and the non-woven material still being produced. By this procedure, the particles do not form any widely undefined areas that change the mechanical properties of the base material or the non-woven material, as is the case with the introduction of plastic extrudates or hot melts over the entire surface. It should be noted that it has proven expedient to heat the particles on the release surface to a higher temperature than the base material and the non-woven are bonded by the particles, which can also be above the melting temperature of the particles.

[0026] In another embodiment of the method according to the present application, in which the net-like base material is provided as a flat net, the net-like composite material is formed from the base material and the non-woven material into a tube, with the non-woven material forming the inner layer of the tube, by overlapping the edge side areas of the flat net-like composite material with each other and connecting them to each other to form an overlap. By dividing the tube into tube segments and forming a bottom at at least one end of the tube segments, such a tube-like composite material can be formed into a bag, with the non-woven material forming the inner layer, which prevents the filling material, such as a granular / powdery cement material, from leaking outwards. This is particularly advantageous if the base material has already been perforated before being bonded to the non-woven material. BRIEF DESCRIPTION OF DRAWINGS

[0027] The application is explained in more detail below using non-limiting exemplary embodiments with reference to the accompanying drawings.

[0028] Figure 1 A first embodiment of an apparatus for producing a flexible net-like composite material according to the present application is schematically shown.

[0029] Figure 2 A second embodiment of an apparatus for producing a flexible net-like composite material according to the present application is schematically shown.

[0030] Figure 3 A reversing apparatus of the apparatus of Figure 2 is shown.

[0031] Figure 4 A reversing apparatus of the apparatus of Figure 1A simplified embodiment of an apparatus for producing flexible mesh composite materials is shown.

[0032] Figure 5 The illustration shows a tube made of a flat mesh composite material according to the present invention. Detailed Implementation

[0033] Now based on Figure 1 The schematic diagram illustrates the first embodiment of the present invention. Figure 1 An apparatus 1 for producing a flexible mesh composite material 2 is shown. The apparatus 1 is provided with a mesh substrate 3 wound on rollers, the substrate 3 comprising at least a portion of a first thermoplastic polymer. The mesh substrate 3 can be a flat or tubular material, optionally with side folds. Additionally, the apparatus 1 is provided with a mesh nonwoven material 4 wound on rollers, the nonwoven material 4 comprising at least a portion of a second thermoplastic polymer. When the apparatus 1 is in operation, using a feeding device (not shown), such as a driven roller pair, the mesh substrate 3 is unwound from its rollers, pulled through a perforating device 5, where it is perforated, and supplied to a release surface 6. This release surface is designed as a heated continuous conveyor belt rotating on rollers, preferably equipped with a surface made of polytetrafluoroethylene (PTFE, known by the brand name "Teflon") or a material having similar properties to PTFE. PTFE has high chemical and heat resistance, a low coefficient of friction, and anti-stick properties. For example, using a spreading roller, discrete particles 7 containing a third thermoplastic polymer are applied in large quantities from a container 8 to a release surface 6 in as uniform a distribution as possible. The temperature of the heated release surface 6 is higher than the softening temperature of the third thermoplastic polymer. The particles 7 are heated on the release surface to above the softening temperature of the third thermoplastic polymer and, in a softened state, adhere sufficiently to the release surface 6 so that they do not fall off the release surface 6 even when transported on the rotating release surface 6. The substrate 3 and the release surface 6 pass through a pair of rollers 9 such that the particles 7 on the release surface 6 face the surface 3a of the substrate 3. The rollers 9 press the particles 7 against the surface 3a of the substrate 3, thereby softening the particles 7 and adhering them to the surface 3a of the substrate 3. Subsequently, the surface 3a of the substrate 3, on which the particles 7 have been transferred, is moved away from the release surface 6, thereby preparing the release surface 6 to be applied with particles 7 again. The surface 3a of the substrate 3 is now cooled until the temperature of the particles 7 is lower than the softening temperature of the third polymer. In this exemplary embodiment, cooling is actively performed using a cooling device 10. However, depending on the ambient temperature, transport speed, and transport length of the substrate 3, passive cooling, such as through ambient air, can also be provided, allowing the particles 7 to cool on the substrate 3. If the substrate 3 with the particles 7 adhering to it is further directly processed, cooling below the softening temperature can be omitted.

[0034] In the next step, the web-like nonwoven material 4 is supplied by unwinding it from its roll using a feeding device (not shown), such as a driven roller, and the nonwoven material 4 is brought together with the substrate 3 via the roller 21, the surface 3a of the substrate 3 to which the particles 7 are adhered facing the surface 4a of the nonwoven material 4. The superimposed layers of the substrate 3 and the nonwoven material 4 are now heated by the heating device 11 to above the softening temperature of the third thermoplastic polymer of the particles 7 adhered to the surface 3a of the substrate 3, and then the substrate 3 and the nonwoven material 4 are pressed together by the pair of rollers 12, whereby the softened particles 7 interconnect the mutually facing surfaces 3a, 4a of the substrate 3 and the nonwoven material 4. The flexible web-like composite material 2 produced in this way is actively cooled using the cooling device 14 while being transported through the device 1, or is passively cooled by allowing it to cool in ambient air, and can be wound onto a roll for further processing.

[0035] Figure 4 Fig. 1 shows schematically an embodiment of a device 1 for producing a flexible web-like composite material 2, which comprises the components described above, wherein the composite material 2 is wound onto a roll for further processing.

[0036] The main advantage of the device 1 and the method performed on it is that the substrate 3 and the nonwoven material 4 are interconnected by a multitude of discrete connection points made of particles 7 containing a third thermoplastic polymer, which connection points extend substantially over the entire connection surface between the substrate 3 and the nonwoven material 4, while being distributed as evenly as possible, resulting in an overall effect of a "full-surface" connection with uniform connection properties. As a result, the cavities in the nonwoven material 4 remain substantially intact.

[0037] In the embodiment of the device 1 as shown in Figure 1 and Figure 4 The substrate 3 is first supplied and, after being applied with the particles 7, is brought together with the nonwoven material 4 and connected. It should be noted, however, that the device 1 is also suitable for initially supplying the nonwoven material 4 and, after applying the particles 7 to the nonwoven material 4, bringing the nonwoven material 4 together with the substrate 3 such that their surfaces 3a, 4a are interconnected by a multitude of connection points consisting of the particles 7.

[0038] In the embodiment of the device 1 as shown in Figure 1In the shown embodiment of the apparatus 1 for producing a flexible net-like composite material 2, the composite material is further processed immediately after its manufacture, wherein after the substrate 3 and the non-woven material 4 are pressed together by a pair of rollers 12, discrete particles 17 containing a fourth thermoplastic polymer are applied on the surface 3b of the substrate 3 opposite to the non-woven material 4, i.e. on the surface 3b of the substrate 3 facing away from the non-woven material 4. The application of the particles 17 is done by applying a bulk of particles 17 from a container 18 onto a heated release surface 16 in as uniform a distribution as possible, for example using a spreading roller. The temperature of the heated release surface 16 is above the softening temperature of the fourth thermoplastic polymer. The particles 17 are heated on the release surface 16 above the softening temperature of the fourth thermoplastic polymer and, in the softened state, adhere sufficiently to the release surface 16 so that they do not fall off the release surface 16 even when they are transported on the rotating release surface 16. The release surface 16 is designed as a heated continuous conveyor belt rotating on rollers, which is preferably equipped with a surface made of PTFE or a material having similar properties as PTFE. The composite material 2 and the release surface 16 are passed through a pair of rollers 19 so that the particles 17 on the release surface 16 are facing the surface 3b of the substrate 3. The pair of rollers 19 presses the particles 17 against the surface 3b of the substrate 3 of the composite material 2, whereby the softened particles 17 adhere to the surface 3b of the substrate 3. Subsequently, the surface 3b of the substrate 3 of the composite material 2, on which the particles 17 are transferred, is moved away from the release surface 16, so that the release surface 16 is ready for another application of particles 17. The composite material 2 is now actively cooled using a cooling device 14 or passively by allowing it to cool in, for example, ambient air, until the temperature of the particles 17 is below the softening temperature of the fourth polymer. Subsequently, the net-like flexible composite material treated in this way is wound onto a roller for further use, for example for the manufacture of bags.

[0039] Examples of preferred materials for the first, second, third and fourth thermoplastic polymers are indicated above.

[0040] Figure 2 Another embodiment of an apparatus 20 for producing a flexible net-like composite material 2 is schematically shown, which performs essentially the same process steps as the apparatus 1 of Figure 1 . As in the embodiment of Figure 1 , the same or similar apparatus components are denoted in Figure 2 by the same reference numerals and, for their explanation, reference is made to the description of the apparatus of Figure 1 . The essential difference between the two apparatuses 1, 20 is that in Figure 2In the device 20, only one release surface 6 is used, through which particles 7 and 17 are successively provided to the two surfaces 3a and 3b of the substrate 3. For this purpose, after the particles 7 are applied to the first surface 3a of the substrate 3, the substrate 3 is flipped in the flipping device 30. Subsequently, the nonwoven material 4 is bonded to the first surface 3a of the substrate on which the particles 7 have been provided. By applying heat and pressure in the heating device 11 and a pair of rollers 12, the substrate 3 and the nonwoven material 4 are connected to each other on their facing surfaces through multiple connection points, as described above. Figure 1 As described in detail. The composite material 2 produced in this way is then supplied again to the release surface 6, so that the surface 3b of the substrate 3 opposite to (i.e., facing away from) the nonwoven material 4 faces the release surface 6. Discrete particles 17 are applied to the surface 3b of the substrate 3 opposite to the nonwoven material 4, and then cooled in the cooling device 14. The composite material 2 processed in this way is then wound into a roll.

[0041] Figure 3 A top view of one embodiment of the flipping device 30 is shown, as it can be... Figure 2 The device 20 is used in that way. For ease of understanding, some device components not needed in the explanation have been omitted. Figure 3 The illustration shows a substrate 3 loaded with particles 7 containing a third thermoplastic polymer on a pair of rollers 9, the particles 7 being applied from container 8 to release surface 6. The substrate 3 with particles 7 is flipped 180° on a first deflection roller 24, then supplied to a first fixed deflection rod 22, where it is deflected 90°, and then supplied to a second fixed deflection rod 23, where it is deflected again by 90°. The substrate 3 is then flipped 180° again around a second deflection roller 25, thereby conducting towards the heated release surface 6. Before contacting the release surface 6, the substrate 3 is bonded to the nonwoven material 4 on roller 21, as described above. Subsequently, the substrate 3 is loaded with particles 17 containing a fourth thermoplastic polymer on a pair of rollers 19, the particles 17 being applied from container 18 to release surface 6.

[0042] Figure 5A tube 15 is schematically shown formed from composite material 2, which is designed to be a flat material. For this purpose, the side regions 2a, 2b of the flat mesh composite material 2 are overlapped and interconnected by a deflection device (not shown) to form an overlapping portion 2c, such that nonwoven material 4 forms the inner layer of the tube 15. The connection of the side regions 2a, 2b of the flat mesh composite material 2 is achieved by introducing a plastic extruder 26 and an extrusion nozzle 27 into the overlapping portion 2c, and then passing the overlapping portion 2c through a pair of rollers 28, thereby pressing them together. Subsequently, a bag can be formed from the tube 15 by dividing the tube 15 into segments and forming a bottom at at least one end of the segments. However, if it has a tubular substrate 3, the composite material 2 can also be divided into segments, and a bottom can be formed at at least one end of the segments. Thus, cross-bottom bags, valve bags, pouches, or mold-filled and sealed bags of shapes known to those skilled in the art can be produced. The composite material 2 used is preferably a material in which the substrate 3 is perforated before being connected to the nonwoven material 4.

Claims

1. A method for producing a flexible mesh composite material (2), the method comprising: Provide a mesh substrate (3) that contains at least a portion of a first thermoplastic polymer; Provide a mesh nonwoven material that contains at least a portion of a second thermoplastic polymer (4); Discrete particles (7) containing a third thermoplastic polymer are applied to the mesh substrate (3) or the mesh nonwoven material (4) by the following steps: providing a release surface (6); providing and arranging a plurality of the discrete particles (7) on the release surface (6), the temperature of the release surface (6) being higher than the softening temperature of the third thermoplastic polymer; heating the particles (7) arranged on the release surface (6) to a temperature higher than the softening temperature of the third thermoplastic polymer; and causing the surfaces (3a, 4a) of the substrate (3) or the nonwoven material (4) to... a) Contact the release surface (6) and the softening particles (7) arranged thereon, such that the particles (7) adhere to the surface (3a, 4a) of the substrate (3) or the nonwoven material (4); then peel the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) on which the particles (7) are adhered from the release surface (6); and optionally cool the particles (7) adhered to the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) to below the softening temperature of the third thermoplastic polymer. Its features The substrate (3) and the nonwoven material (4) are combined together, with the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) on which the particles (7) are adhered facing the surface (4a, 3a) of the nonwoven material (4) or the substrate (3). The substrate (3) and the nonwoven material (4) are pressed together, whereby the particles (7) interconnect the mutually facing surfaces (3a, 4a) of the substrate (3) and the nonwoven material (4). Optionally, the particles (7) adhering to the surfaces (3a, 4a) of the substrate (3) or the nonwoven material (4) are heated to above the softening temperature of the third thermoplastic polymer before the substrate (3) and the nonwoven material (4) are pressed together. And optionally, the composite material (2) produced thus from the substrate (3) and the nonwoven material (4) is cooled.

2. The method according to claim 1, characterized in that, After the substrate (3) and the nonwoven material (4) are pressed together, discrete particles (17) containing a fourth thermoplastic polymer are applied to the surface (3b) of the substrate (3) opposite to the nonwoven material (4) by: providing a release surface (16); providing and arranging a plurality of the discrete particles (17) on the release surface (16), the temperature of the release surface (16) being higher than the softening temperature of the fourth thermoplastic polymer; and heating the particles (17) arranged on the release surface (16) to a temperature higher than the softening temperature of the fourth thermoplastic polymer. The softening temperature of the fourth thermoplastic polymer is used to bring the surface (3b) of the substrate (3) opposite to the nonwoven material (4) into contact with the release surface (16) and the softening particles (17) arranged thereon, so that the particles (17) adhere to the surface (3b) of the substrate (3), and then the surface (3b) of the substrate (3) on which the particles (17) are adhered is peeled off from the release surface (16), and optionally the particles (17) adhered to the surface (3b) of the substrate (3) are cooled to below the softening temperature of the fourth thermoplastic polymer.

3. The method according to claim 2, characterized in that, Before applying the particles (17) to the surface (3b) of the substrate (3) opposite to the nonwoven material (4), the substrate (3) or the composite material (2) made of the substrate (3) and the nonwoven material (4) is flipped, and the surface (3b) of the substrate (3) faces the release surface (6), which is also used to apply the particles (7) containing a third thermoplastic polymer.

4. The method according to claim 2 or 3, characterized in that, The mesh substrate (2) is tubular, and the tubular substrate may optionally have side folds.

5. The method according to any one of the preceding claims, characterized in that, The substrate (3) comprises at least one layer made of plastic tape fabric, preferably made of PP, HDPE or PET.

6. The method according to claim 5, characterized in that, The plastic tape fabric has an optional printed coating or a plastic film laminated thereon.

7. The method according to any one of claims 1 to 4, characterized in that, The substrate (3) is a single or multiple layers of optionally printed plastic film, preferably made of PP, LLDPE, LDPE, HDPE or PET.

8. The method according to any one of the preceding claims, characterized in that, The substrate (3) is perforated before it is bonded to the nonwoven material (4).

9. The method according to any one of the preceding claims, characterized in that, The nonwoven material (4) is spunbond nonwoven fabric, carded nonwoven fabric, spunlace material, meltblown material, spunbond material, or a composite material made of the above materials.

10. The method according to any one of the preceding claims, characterized in that, The first and / or second thermoplastic polymer is selected from: PET, PP, PE or copolymers or terpolymers containing two or three of the following monomers: ethylene, propylene, vinyl acetate, alkyl acrylate, maleic anhydride, α-olefin.

11. The method according to any one of the preceding claims, characterized in that, The third and / or fourth thermoplastic polymers are selected from: PET, PP, PE or copolymers or terpolymers containing two or three of the following monomers: ethylene, propylene, vinyl acetate, alkyl acrylate, maleic anhydride, α-olefin.

12. The method according to any one of the preceding claims, characterized in that, The average particle size of the particles (7) containing the third thermoplastic polymer is less than or equal to 1000 μm, and / or the average particle size of the particles (17) containing the fourth thermoplastic polymer is 80 to 800 μm, preferably 100 to 500 μm, with the particle size as uniform as possible, especially with a particle size difference of less than 3 times, which is particularly preferred for the particles (17) containing the fourth thermoplastic polymer.

13. The method according to any one of the preceding claims, characterized in that, Basis weight between 1g and 20g / m 2 Between 3g and 5g / m 2 The particles (7, 17) are applied to the substrate (3) and / or the nonwoven material (4).

14. The method according to any one of the preceding claims, characterized in that, When the particles (7, 17) are attached to the substrate (3) or the nonwoven material (4), the particles (7, 17) are adjusted to a temperature higher than their softening temperature.

15. The method according to any one of claims 1 to 3 and 5 to 14, characterized in that, The mesh substrate (3) is a flat mesh, and the mesh composite material (2) made of the substrate (3) and the nonwoven material (4) is formed into a tube (15) by stacking the side regions (2a, 2b) of the flat mesh composite material (2) on each other and interconnecting them to form an overlapping portion (2c). The nonwoven material (4) forms the inner layer of the tube (15).

16. The method according to any one of the preceding claims, characterized in that, The tube (15) produced according to claim 15 or the composite material (2) including the tubular substrate (3) according to claim 4 is divided into tube segments, and a bottom is formed at at least one end of the tube segment.

17. An apparatus (1, 20) for producing a flexible mesh composite material (2), said apparatus (1, 20) comprising: Feeding device for supplying a mesh substrate (3) containing at least a portion of a first thermoplastic polymer, Feeding device for supplying a mesh nonwoven material (4) containing at least a portion of a second thermoplastic polymer, An apparatus for applying discrete particles (7) containing a third thermoplastic polymer to the mesh substrate (3) or the mesh nonwoven material (4), the apparatus for applying the particles (7) comprising: a heatable release surface (6); a container (8) from which a plurality of the discrete particles (7) can be applied to the release surface (6), the release surface being heatable to a temperature above the softening temperature of the third thermoplastic polymer; a pair of rollers (9) for contacting the surfaces (3a, 4a) of the substrate (3) or the nonwoven material (4) with the release surface (6) and the softened particles (7) arranged thereon, such that the particles (7) adhere to the surfaces (3a, 4a) of the substrate (3) or the nonwoven material (4); and, optionally, a cooling device (10) for cooling the particles (7) adhered to the surfaces (3a, 4a) of the substrate (3) or the nonwoven material (4) to a temperature below the softening temperature of the third thermoplastic polymer. Its features are, The device (1, 20) also includes: A device (21) for bonding the substrate (3) and the nonwoven material (4) together such that the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) on which the particles (7) are adhered faces the surface (4a, 3a) of the nonwoven material (4) or the substrate (3). Optionally, a heating device (11) is provided for heating particles (7) adhered to the surfaces (3a, 4a) of the substrate (3) or the nonwoven material (4) to a temperature above the softening temperature of the third thermoplastic polymer. A pair of rollers (12) are used to press the substrate (3) and the nonwoven material (4) together, such that softened particles (7) interconnect the facing surfaces (3a, 4a) of the substrate (3) and the nonwoven material (4). In addition, optionally, a cooling device (14) is provided for cooling the composite material (2) thus produced from the substrate (3) and the nonwoven material (4).

18. The device according to claim 17, characterized in that, An apparatus for applying discrete particles (17) containing a fourth thermoplastic polymer to the mesh substrate (3), the apparatus for applying the particles (17) comprising: a heatable release surface (6, 16); a container (18) from which a plurality of the discrete particles (17) can be applied to the discrete surface (6, 16), the discrete surface (6, 16) being heatable to a temperature above the softening temperature of the fourth thermoplastic polymer; a pair of rollers (19) for contacting the surface (3b) of the substrate (3) with the release surface (6, 16) and the softening particles (17) arranged thereon, such that the particles (17) adhere to the surface (3b) of the substrate (3); and, optionally, a cooling device (14) for cooling the particles (17) adhered to the surface (3b) of the substrate (3) to a temperature below the softening temperature of the fourth thermoplastic polymer.

19. The device according to claim 18, characterized in that, A flipping device (30) for flipping the substrate (3) or the composite material (2) made of the substrate (3) and the nonwoven material (4) before applying particles (17) containing a fourth thermoplastic polymer to the surface (3b) of the substrate (3) opposite to the nonwoven material (4), and a means for supplying the flipped composite material (2) to the release surface (6), the release surface (6) also for applying particles (7) containing a third thermoplastic polymer such that the surface (3b) of the substrate (3) opposite to the nonwoven material (4) faces the release surface (6).

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