Method and device for producing a flexible web-type composite material
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-04-23
- Publication Date
- 2026-03-11
AI Technical Summary
Existing methods for producing flexible web-shaped composite materials, such as non-slip packaging bags, face issues like mechanical property alteration of nonwoven fibers due to hot melt adhesives or extruded polyolefin polymers, high material consumption, and difficulties in recycling, as well as inadequate slip resistance when bags are stacked.
A method involving a web-shaped substrate and nonwoven material connected using discrete thermoplastic particles that are heated and adhered to the surfaces, creating a full-surface connection with even distribution of particles, which maintains the integrity of the fleece material's cavities and allows for recycling, and additional particles applied to enhance slip resistance.
The method achieves high slip resistance for stacked bags without the need for additional securing means, reduces material consumption, and enables recycling of the composite material, ensuring effective mechanical interlocking and maintaining the fleece's retention function.
Smart Images
Figure EP2024061002_07112024_PF_FP_ABST
Abstract
Description
[0001] Method and device for producing a flexible web-shaped composite material
[0002] The invention relates to a method for producing a flexible web-shaped composite material according to the preamble of claim 1.
[0003] The invention further relates to a device for producing a flexible web-shaped composite material, according to the preamble of claim 17.
[0004] Document EP 3 463 805 B1 describes non-slip, flexible materials and methods for their production and use. In these processes, individual thermoplastic particles heated to a sticky state are applied to a surface of a thermoplastic flexible carrier, which can be used as a slip-resistant flexible packaging material. Non-slip flexible packaging bags whose outer surface has roughened projections are also disclosed, as well as methods for their production and use. When such bags lie on top of one another, the roughened projections prevent mutual slipping, even if the material of the bags itself is not slip-resistant, because the projections interlock. It is also mentioned that these projections create an effective, non-slip mechanical interlock with a fibrous engagement material, such as a commercially available nonwoven, which is placed, for example, between two bags.The nonwoven fabric can be lifted vertically from the rough surface. This document further describes that the bag can be made of a film and / or a woven fabric and / or a nonwoven fabric. Fig. 12a of EP 3 463 805 B1 shows a tubular web of plastic film with roughening projections applied to one surface and a nonwoven strip affixed to the opposite surface, either by a fiber-sprayed hot-melt adhesive or by extrusion lamination, in which a continuous application of narrow strands of an extruded polyolefin polymer is carried out to encapsulate the fibers of the nonwoven fabric and fix them to the film, and the sandwich arrangement of film / melt / nonwoven is pressed between a pair of metal rollers.
[0005] A disadvantage of this type of film-nonwoven composite is that the hot-melt adhesive or extruded polyolefin polymer alters the mechanical properties of the nonwoven. The hot-melt adhesive or extruded polyolefin polymer coats the nonwoven fibers and then presses them against the film. As a result, the hot-melt adhesive or extruded polyolefin polymer penetrates the nonwoven down to its surface facing away from the film, causing it to become rigid and impairing the mechanical bond with the rough surface of the film. The described methods of attaching the nonwoven to the film also require a high amount of hot-melt adhesive or polyolefin polymer, which is unnecessary for the desired mechanical bonding function of the nonwoven.The use of hot melt is also disadvantageous because hot melt adhesives are expensive and make it difficult to recycle items made from the film-nonwoven composite material.
[0006] Document US 2015 / 0036952 A1 describes the production of a packaging bag with a slip-resistant coating. A readily extrudable olefinic elastomer is applied from an extrusion head to a woven polypropylene packaging bag and immediately flattened with rollers into several spaced-apart strips, with the aim of increasing the friction coefficient of the bag's surface.
[0007] Document US 2019 / 02913337 A1 discloses a slip-resistant, heat-sealable plastic packaging bag, as well as a method and apparatus for its production. The bag is made of a flexible plastic material, to whose surface a plurality of separate, slip-resistant projections made of a thermoplastic polymer are applied. The material of the slip-resistant projections is said to be different from the material of the bag.
[0008] DE 40 33 499 A1 discloses a method for finishing a thermoplastic film web for further processing into bags. The bags have perforated areas covered with nonwoven strips. The nonwoven strips are attached to the film web with a connecting means, whereby the film web, the nonwoven strip, and the connecting means are made of the same thermoplastic material. This method solves the problem that plastic bags coated with adhesives are no longer recyclable or can only be recycled for inferior applications.During bag production, the molten bonding agent is applied along the edge regions of the nonwoven strip between the nonwoven strip and the film web, and bonding pressure is exerted on the nonwoven strip, bonding agent, and film web, so that the thermoplastic of the bonding agent at least partially penetrates the nonwoven strip and bonds the nonwoven strip to the film web while the thermoplastic hardens. The process described in DE 40 33 499 A1 has the disadvantage described above that the partial or complete penetration of plastic into the nonwoven impairs its mechanical locking with the rough surfaces of adjacent bags. Furthermore, the nonwoven strip is only applied to its edges, so that the nonwoven is freely movable between its edges due to its elastic properties, making it unsuitable for preventing bags lying on top of one another from slipping.This problem is not addressed in DE 40 33 499 A1 because the nonwoven strips in the disclosed bags only serve to cover perforations in the bag body made from the film web. For this reason alone, a full-surface attachment of the nonwoven strip to the film web by applying the melted bonding agent and subsequently applying bonding pressure would not be possible, because this would close the perforations in the film web.
[0009] From document WO 2011 / 018318 A1, a method for producing a sack is known, wherein the sack contains a plastic nonwoven material. The method comprises providing an at least two-layer flat web material with a first layer of a plastic nonwoven material and a second layer of a plastic coating, forming a tube from the flat web material by placing the side regions of the flat web material on top of one another to form an overlap and connecting them to one another, wherein after forming the tube, the plastic coating faces outwards and the plastic nonwoven material layer faces inwards, separating the tube into tube pieces, and forming a base on at least one end of a tube piece. Before separating the tube into tube pieces, the at least two-layer flat web material or the tube produced therefrom is perforated.This is necessary because, although the plastic nonwoven material layer is permeable to air - which is important when filling the bags so that the air can escape from the inside of the bag - the plastic coating prevents the air from escaping. The disadvantage of perforating the flat sheet material that comprises the plastic nonwoven material layer and the plastic coating is that this also perforates the plastic nonwoven material layer. With its many fibers, a nonwoven layer forms a labyrinth that allows air to pass through but holds back the usually granular or powdery filling material contained in the bag, thereby preventing the filling material from escaping from the bag. If the nonwoven layer is now perforated, the perforation forms a straight passage through the entire flat sheet material, so that the nonwoven layer can no longer prevent the filling material from passing through the flat sheet material that forms the bag wall.The object of the present invention is to propose a method and apparatus for producing a flexible web-like composite material that overcomes or at least mitigates the aforementioned disadvantages of the prior art. In one aspect of the invention, the flexible web-like composite material produced according to the invention is used for the production of bags.
[0010] The invention solves the stated problem by providing a method for producing a flexible web-shaped composite material having the features of claim 1 and a device having the features of claim 17. Advantageous embodiments of the invention are set out in dependent claims, the description and the drawings.
[0011] The method according to the invention for producing a flexible sheet-like composite material comprises providing a sheet-like substrate which at least partially contains a first thermoplastic polymer, providing a sheet-like nonwoven material which at least partially contains a second thermoplastic polymer, applying discrete particles containing a third thermoplastic polymer to the sheet-like substrate or to the sheet-like nonwoven material by providing a release surface, providing and arranging a plurality of the discrete particles on the release surface, wherein the release surface has a temperature which is above a softening temperature of the third thermoplastic polymer, heating the particles arranged on the release surface above the softening temperature of the third thermoplastic polymer,Bringing a surface of the substrate or 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 nonwoven material, then removing the surface of the substrate or nonwoven material with the particles adhering thereto from the release surface, and optionally cooling the particles adhering to the surface of the substrate or nonwoven material below the softening temperature of the third thermoplastic polymer, bringing the substrate and the nonwoven material together, wherein the surface of the substrate or nonwoven material with the particles adhering thereto faces a surface of the nonwoven material or the substrate, pressing the substrate and the nonwoven material together, whereby the particles bond the mutually facing surfaces of the substrate and the nonwoven material to one another,Where appropriate, prior to pressing the substrate and the nonwoven material together, the particles adhering to the surface of the substrate or the nonwoven material are heated above the softening temperature of the third thermoplastic polymer, and the composite material thus produced from the substrate and the nonwoven material is optionally cooled.
[0012] This process connects the substrate and the nonwoven material to one another through a plurality of discrete connection points made of particles containing the third thermoplastic polymer. The connection points are distributed as evenly as possible across essentially the entire connecting surface between the substrate and the nonwoven material, creating the overall effect of a "full-surface" connection with homogeneous bonding properties. In contrast to the prior art connections of a substrate and a nonwoven by means of extrusion lamination or bonding, according to the invention, the cavities of the nonwoven material remain largely intact, allowing them to be retained both for a positive connection with a material made slip-resistant by the application of plastic particles and for the retention of powdery or granular material through the labyrinth channels formed by the cavities of the nonwoven.
[0013] Advantageously, the process according to the invention eliminates the need for expensive equipment such as extruders or hot-melt melters. Furthermore, the material consumption of the bonding agent, i.e., the particles, is significantly lower than when bonding a substrate to a nonwoven using hot-melt adhesive or extruded polymer. A further positive effect of the invention is the possibility of jointly recycling the substrate and nonwoven.
[0014] In a further development of the invention, after pressing the substrate and the nonwoven material 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, wherein the release surface has a temperature that is above a softening temperature of the fourth thermoplastic polymer, heating the particles arranged on the release surface 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, and then removing 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 below the softening temperature of the fourth thermoplastic polymer. "Cooling" in this text generally refers to active cooling using a cooling device or passive cooling by allowing it to cool, e.g., in ambient air.
[0015] The flexible web-like composite material produced in this way thus meets all the requirements for being processed into bags that are characterized by high slip resistance when stacked on top of one another. This is because the particles applied to a surface of the substrate that forms an outer surface of the bag engage positively with the cavities of the nonwoven material of the composite material, which is arranged on an outer surface of the bag that is opposite the outer surface of the bag with the particles. Since the nonwoven material is connected to the substrate over the entire connection surface by a plurality of connection points, it does not detach even under shear forces that occur when a stack of bags lying on top of one another, in which one side with nonwoven material of one bag faces a side with particles on the substrate of an adjacent bag, is tilted. This meansHigh tilt angles, typically 35° and more, are possible without the bags slipping; instead, the stack of bags falls over first. This eliminates the need for stretch film, shrink film, or other means of load securing when stacking bags.
[0016] If the substrate or the composite of the substrate and the nonwoven material is turned over before the application of the particles containing the fourth thermoplastic polymer on the surface of the substrate opposite the nonwoven material and this surface of the substrate is turned towards the release surface which also serves for applying the particles containing a third thermoplastic polymer, the device on which the web-shaped composite material is produced according to the method according to the invention can be considerably simplified because a single release surface is used for applying the particles on both sides of the composite material.
[0017] The web-shaped substrate may be tubular for the production of bags, whereby, depending on the type of bags to be produced from the composite material, the tubular substrate may optionally be provided with side gussets.
[0018] In a preferred embodiment of the invention, the substrate comprises at least one layer of a plastic ribbon fabric, preferably made of PP, HDPE, or PET. The plastic ribbon fabric can have an optionally printed coating or a laminated plastic film, which serves, for example, as a carrier for printing or as a barrier layer, e.g., as a moisture barrier layer.
[0019] In an alternative embodiment of the invention, the substrate is a single- or multi-layer, optionally printed plastic film, preferably made of PP, LLDPE, LDPE, HDPE or PET.
[0020] For certain applications, the composite material produced according to the invention must be permeable to air. For example, when the composite material is used to produce valve bags that are filled with powdery or granular contents by means of an air stream, whereby the air must be able to escape from the bag. For such applications, the substrate is perforated before being joined to the nonwoven material. It is essential that only the substrate, and not the nonwoven material, is perforated, because otherwise the nonwoven material would lose its retention function for the contents, for example, very fine-grained / fine-dust cement.
[0021] Preferably, the nonwoven material is a spunbonded nonwoven or a carded nonwoven or a spunlace material or a meltblown material or a spunbond material or a composite material of the materials mentioned.
[0022] It has proven effective if the first and / or second thermoplastic polymer is selected from: 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-olefin. The first and second thermoplastic polymers can be selected from the same material or from different materials.
[0023] Preferably, the third and / or fourth thermoplastic polymers are selected from: 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-olefin. The third and fourth thermoplastic polymers can be selected from the same material or from different materials.
[0024] In a preferred embodiment of the invention, the particles containing the third thermoplastic polymer have an average particle size of less than or equal to 1000 pm. In a further preferred embodiment of the invention, the particles containing the fourth thermoplastic polymer have an average particle size between 80 and 800 pm, preferably between 100 and 500 pm, with particle sizes that are as uniform as possible, in particular with size differences of less than a factor of 3, being particularly preferred for largely homogeneous bonding and slip resistance properties. The particles containing the fourth thermoplastic polymer are selected by sieving with sieves of defined mesh size, which ensures good, uniform particle sizes.
[0025] According to the invention, it is preferred if the particles have a basis weight between 1 g and 20 g per m 2 , preferably between 3 g and 5 g per m 2, are applied to the substrate and / or the nonwoven material. These basis weights are far lower than the basis weights of extrusion bonds, but still ensure sufficient bond strength. The bond strength can be adjusted by selecting an appropriate basis weight so that the nonwoven material does not detach from the substrate due to shear forces, but can be pulled off the substrate by applying force, e.g., manually, perpendicular to the bonding surface. If the basis weight of the particles is within the specified range, this also ensures that the particles do not clog the cavities in the nonwoven material.
[0026] According to the invention, the particles can be set to a temperature above their softening temperature but below their melting temperature when bonding to the substrate or nonwoven material. This embeds the particles in the substrate or nonwoven material, leaving the nonwoven material or its fibers essentially undamaged, while still maintaining good adhesion properties between the substrate and the nonwoven material (through positive locking). With this procedure, the particles do not form large, undefined areas that alter the mechanical properties of the substrate or nonwoven material, as is the case with the full-surface application of plastic extrudate or hot melt.It should be mentioned that it has been found to be advantageous if the heating of the particles at the release surface takes place to a higher temperature, which may even be above the melting temperature of the particles, than when the substrate and fleece are bonded by means of the particles.
[0027] In a further embodiment of the method according to the invention, in which the web-shaped substrate is provided as a flat web, the web-shaped composite material is formed from the substrate and the nonwoven material into a tube by placing the side regions of the flat, web-shaped composite material on top of one another to form an overlap and connecting them to one another, wherein the nonwoven material forms an inner layer of the tube. Such a tubular composite material can be formed into bags, in which the nonwoven material forms an inner layer that prevents the contents, such as fine-grained / dusty cement material, from escaping to the outside, by separating the tube into tube pieces and forming a base at at least one end of the tube pieces. This is particularly advantageous if the substrate has been perforated before being connected to the nonwoven material.
[0028] The invention is explained in more detail below with reference to the drawings by means of non-limiting embodiments.
[0029] Fig. 1 shows schematically a first embodiment of an apparatus for producing a flexible web-shaped composite material according to the invention.
[0030] Fig. 2 shows schematically a second embodiment of an apparatus for producing a flexible web-shaped composite material according to the invention.
[0031] Fig. 3 shows a turning device of the device of Fig. 2.
[0032] Fig. 4 schematically shows a simpler embodiment of the device for producing a flexible web-like composite material shown in Fig. 1. Fig. 5 shows the production of a hose from a flat web-like composite material according to the invention.
[0033] A first embodiment of the invention will now be explained with reference to the schematic representation in Fig. 1. Fig. 1 shows a device 1 for producing a flexible web-shaped composite material 2. This device 1 is provided with a web-shaped substrate 3, which at least partially contains a first thermoplastic polymer, wound up on a roll. The web-shaped substrate 3 can be a flat material or a tubular material, optionally with side folds. Furthermore, the device 1 is provided with a web-shaped nonwoven material 4, which at least partially contains a second thermoplastic polymer, wound up on a roll. During operation of the device 1, the web-shaped substrate 3 is unwound from its roll by means of feed means (not shown), such as driven pairs of rollers, pulled through a perforation device 5 where it is perforated, and fed to a release surface 6.The release surface is designed as a heated, endless conveyor belt circulating around rollers, preferably with a surface made of polytetrafluoroethylene (PTFE), known under the brand name "Teflon," or a material with similar properties to PTFE. PTFE has high chemical and thermal resistance, a low coefficient of friction, and is anti-adhesive. Discrete particles 7 containing a third thermoplastic polymer are applied from a container 8, for example, by means of a spreading roller, in a large number and distributed as evenly as possible onto the release surface 6. The heated release surface 6 has a temperature that is above a softening temperature of the third thermoplastic polymer.The particles 7 heat up on the release surface above the softening temperature of the third thermoplastic polymer and, in their softened state, adhere sufficiently to the release surface 6 that they do not fall off the release surface 6 even during their transport on the rotating release surface 6. The substrate 3 and the release surface 6 pass through a pair of rollers 9, so that the particles 7 on the release surface 6 face a surface 3a of the substrate 3. The pair of rollers 9 presses the particles 7 against the surface 3a of the substrate 3, causing the softened particles 7 to adhere to the surface 3a of the substrate 3. The surface 3a of the substrate 3, with the particles 7 transferred thereto, then moves away from the release surface 6, which is thus ready for further application of particles 7. The surface 3a of the substrate 3 is now cooled until the particles 7 have a temperature below the softening temperature of the third polymer.In this embodiment, cooling is performed actively by means of a cooling device 10. Depending on the ambient temperature, transport speed, and transport length of the substrate 3, passive cooling, e.g., by ambient air, can also be provided, in which the particles 7 are allowed to cool on the substrate 3. If the substrate 3 is further processed directly with the particles 7 adhering to it, cooling below the softening temperature can be omitted.
[0034] In the next step, the web-shaped nonwoven material 4 is fed by unwinding it from its roll by means of feed means not shown, such as driven rollers, and the nonwoven material 4 is brought together with the substrate 3 via a roller 21, wherein the surface 3a of the substrate 3 with the particles 7 adhering thereto faces a surface 4a of the nonwoven material 4. The superimposed layers of substrate 3 and nonwoven material 4 are then heated by means of a heating device 11 above the softening temperature of the third thermoplastic polymer of the particles 7 adhering to the surface 3a of the substrate 3, followed by the pressing together of the substrate 3 and the nonwoven material 4 by means of a pair of rollers 12, whereby the softened particles 7 bond the mutually facing surfaces 3a, 4a of the substrate 3 and the nonwoven material 4 to one another.The flexible web-like composite material 2 produced in this way is finally cooled either actively by means of a cooling device 14 or passively by cooling in the ambient air during transport through the device 1, and can be wound onto a roll for further processing. An embodiment of the device 1 for producing the flexible web-like composite material 2, which comprises the parts described so far and in which the composite material 2 is wound onto a roll for further processing, is shown schematically in Fig. 4.
[0035] The essential advantage of the device 1 and the method implemented thereon is that the substrate 3 and the nonwoven material 4 are bonded together by a plurality of discrete bonding points made of the particles 7 containing the third thermoplastic polymer. The bonding points are distributed as evenly as possible and extend essentially over the entire bonding surface between the substrate 3 and the nonwoven material 4, creating the overall effect of a "full-surface" bond with homogeneous bonding properties. The cavities of the nonwoven material 4 remain largely intact.
[0036] In the embodiment of the device 1 shown in Fig. 1 and Fig. 4, the substrate 3 is first fed and, after the particles 7 have been applied, is brought together and bonded to the nonwoven material 4. However, it should be noted that the device 1 is also suitable for first feeding the nonwoven material 4 and, after the particles 7 have been applied to the nonwoven material 4, bringing it together with the substrate 3 so that their surfaces 3a, 4a are connected to one another by a plurality of connection points consisting of the particles 7.
[0037] In the embodiment of the device 1 for producing the flexible web-shaped composite material 2 shown in Fig. 1, the composite material is further treated immediately after its production in that, after the substrate 3 and the nonwoven material 4 have been pressed together by the pair of rollers 12, discrete particles 17 containing a fourth thermoplastic polymer are applied to the surface 3b of the substrate 3 opposite the nonwoven material 4, i.e. facing away from it. The particles 17 are applied in that the particles 17 are applied from a container 18, for example by means of a spreading roller, in a large number and in as uniform a distribution as possible onto a heated release surface 16. The heated release surface 16 has a temperature which is above a softening temperature of the fourth thermoplastic polymer.The particles 17 heat up 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 that they do not fall off the release surface 16 even during their transport on the rotating release surface 16. The release surface 16 is designed as a heated endless conveyor belt circulating around rollers, which is preferably equipped with a surface made of PTFE or a material with properties similar to PTFE. The composite material 2 and the release surface 16 pass through a pair of rollers 19 so that the particles 17 on the release surface 16 face 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, with the particles 17 transferred thereto, is removed from the release surface 16, which is thus ready for the renewed application of particles 17. The composite material 2 is then cooled actively by means of a cooling device 14 or passively by allowing it to cool, e.g., in ambient air, until the particles 17 have a temperature below the softening temperature of the fourth polymer. The thus-treated, flexible web-like composite material is then wound onto a roll for further use, for example, for the production of bags.
[0038] Examples of preferred materials for the first, second, third and fourth thermoplastic polymers have been given earlier in the text.
[0039] Fig. 2 schematically shows a further embodiment of a device 20 for producing a flexible web-shaped composite material 2, which essentially carries out the same method steps as the device 1 of Fig. 1. Identical or similar device parts as in the embodiment of Fig. 1 are provided with the same reference numerals in Fig. 2 and for their explanation reference is made to the description of the device in Fig. 1. The essential difference between the two devices 1, 20 is that in the device 20 of Fig. 2 only one release surface 6 is used, with which both surfaces 3a, 3b of the substrate 3 are provided one after the other with particles 7, 17. For this purpose, the substrate 3 is turned in a turning device 30 after the particles 7 have been applied to its first surface 3a. The nonwoven material 4 is then brought together with the first surface 3a of the substrate provided with the particles 7.By the action of heat and pressure in the heating device 11 and the pair of rollers 12, the substrate 3 and the nonwoven material 4 are connected to one another at their mutually facing surfaces by a plurality of connection points, as described in detail above with reference to Fig. 1. The composite material 2 produced in this way is then fed again to the release surface 6 in such a way that the surface 3b of the substrate 3 opposite the nonwoven material 4, i.e. facing away from it, faces the release surface 6. Discrete particles 17 are applied to this surface 3b of the substrate 3 opposite the nonwoven material 4 and then cooled in the cooling device 14. The composite material 2 treated in this way is then wound up into a roll.
[0040] Fig. 3 shows a plan view of an embodiment of a turning device 30, such as can be used in the device 20 of Fig. 2. To facilitate understanding of the drawing, some device parts not required for the explanation have been omitted. The illustration in Fig. 3 shows the substrate 3, which has already been subjected to the particles 7 containing the third thermoplastic polymer on the pair of rollers 9, wherein the particles 7 are applied from the container 8 to the release surface 6. The substrate 3 provided with the particles 7 is turned 180° on a first deflection roller 24, then fed to a first fixed deflection rod 22, where it is deflected 90°, then fed to a second fixed deflection rod 23, where it is deflected again 90°. The substrate 3 is then turned 180° again around a second deflection roller 25 and is thereby guided in the direction of the heated release surface 6.Before the substrate 3 comes into contact with the release surface 6, it is brought together with the nonwoven material 4 on the roller 21, as described above. Subsequently, the substrate 3 is impinged on the roller pair 19 with the particles 17 containing the fourth thermoplastic polymer, whereby the particles 17 are applied from the container 18 to the release surface 6.
[0041] Fig. 5 schematically shows the forming of a tube 15 from the composite material 2, which is designed as a flat material. For this purpose, the side regions 2a, 2b of the flat, web-shaped composite material 2 are placed on top of one another by deflection means (not shown), forming an overlap 2c, and are connected to one another, so that the nonwoven material 4 forms an inner layer of the tube 15. The connection of the side regions 2a, 2b of the flat, web-shaped composite material 2 takes place by introducing a plastic extrudate into the overlap 2c by means of an extruder 26 and an extrusion nozzle 27, and the overlap 2c is then passed through a pair of rollers 28 and pressed together. Bags can then be formed from the tube 15 by separating the tube 15 into tube pieces and forming a base at at least one end of the tube pieces.However, the composite material 2, if it has a tubular substrate 3, can also be separated into tubular pieces, and a bottom can be formed at at least one end of the tubular pieces. This allows the production of cross-bottom bags, valve bags, pouches, or form-fill-and-seal bags, the designs of which are well known to those skilled in the art. The composite material 2 used is preferably a material whose substrate 3 has been perforated before being bonded to the nonwoven material 4.
Claims
Claims:
1. A method for producing a flexible web-shaped composite material (2), comprising providing a web-shaped substrate (3) which at least partially contains a first thermoplastic polymer, providing a web-shaped nonwoven material (4) which at least partially contains a second thermoplastic polymer, applying discrete particles (7) which contain a third thermoplastic polymer to the web-shaped substrate (3) or to the web-shaped nonwoven material (4), by Providing a release surface (6), providing and arranging a plurality of the discrete particles (7) on the release surface (6), wherein the release surface (6) has a temperature which is above a softening temperature of the third thermoplastic polymer, heating the particles (7) arranged on the release surface (6) above the softening temperature of the third thermoplastic polymer, bringing a surface (3a, 4a) of the substrate (3) or of the nonwoven material (4) into contact with the release surface (6) and the softened particles (7) arranged thereon, such that the particles (7) adhere to the surface (3a, 4a) of the substrate (3) or of the nonwoven material (4), subsequently removing the surface (3a, 4a) of the substrate (3) or of the nonwoven material (4) with the particles (7) adhering thereto from the release surface (6), and optionally cooling the particles (7) arranged on the surface (3a,4a) of the substrate (3) or the nonwoven material (4) adhering particles (7) below the softening temperature of the third thermoplastic polymer, characterized by bringing together the substrate (3) and the nonwoven material (4), wherein the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) with the particles (7) adhering thereto faces a surface (4a, 3a) of the nonwoven material (4) or the substrate (3), pressing the substrate (3) and the nonwoven material (4) together, whereby the particles (7) bond the mutually facing surfaces (3a, 4a) of the substrate (3) and the nonwoven material (4) to one another, wherein optionally before pressing the substrate (3) and the nonwoven material (4) together, heating the particles adhering to the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) (7) above the softening temperature of the third thermoplastic polymer,and optionally cooling the composite material (2) thus produced from the substrate (3) and the nonwoven material (4)., 2. Method according to claim 1, characterized in that after pressing together the substrate (3) and the nonwoven material (4) on the nonwoven material (4) opposite surface (3b) of the substrate (3) discrete particles (17) are applied, which contain a fourth thermoplastic polymer, by Providing a release surface (16), providing and arranging a plurality of the discrete particles (17) on the release surface (16), wherein the release surface (16) has a temperature which is above a softening temperature of the fourth thermoplastic polymer, heating the particles (17) arranged on the release surface (16) above the softening temperature of the fourth thermoplastic polymer, bringing the surface (3b) of the substrate (3) opposite the nonwoven material (4) into contact with the release surface (16) and the softened particles (17) arranged thereon, so that the particles (17) adhere to the surface (3b) of the substrate (3), and then removing the surface (3b) of the substrate (3) with the particles (17) adhering thereto from the release surface (16), and optionally cooling the particles (17) adhering to the surface (3b) of the substrate (3) below the softening temperature of the fourth thermoplastic Polymers.
3. Method according to claim 2, characterized in that the substrate (3) or the composite (2) of the substrate (3) and the nonwoven material (4) is turned over before the application of the particles (17) on the surface (3b) of the substrate (3) opposite the nonwoven material (4) and this surface (3b) of the substrate (3) is turned towards the release surface (6), which also serves for the application of the particles (7) containing a third thermoplastic polymer.
4. Method according to claim 2 or 3, characterized in that the web-shaped substrate (2) is tubular, wherein the tubular substrate is optionally provided with side folds.
5. Method according to one of the preceding claims, characterized in that the substrate (3) has at least one layer of a plastic ribbon fabric, preferably of PP, HDPE or PET.
6. Method according to claim 5, characterized in that the plastic ribbon fabric has an optionally printed coating or a laminated plastic film.
7. Method according to one of claims 1 to 4, characterized in that the substrate (3) is a single- or multi-layer, optionally printed, plastic film, preferably made of PP, LLDPE, LDPE, HDPE or PET.
8. Method according to one of the preceding claims, characterized in that the substrate (3) is perforated before it is combined with the nonwoven material (4).
9. Method according to one of the preceding claims, characterized in that the nonwoven material (4) is a spunbonded nonwoven or a carded nonwoven or a spunlace material or a meltblown material or a spunbond material or a composite material made of the said materials.
10. Process according to one of the preceding claims, characterized in that the first and / or the second thermoplastic polymer is selected from: PET, PP, PE, or a co- or terpolymer containing two or three of the following monomers: ethylene, propylene, vinyl acetate, alkyl acrylate, maleic anhydride, alpha-olefin.
11. Process according to one of the preceding claims, characterized in that the third and / or fourth thermoplastic polymer is selected from: PET, PP, PE, or a co- or terpolymer containing two or three of the following monomers: ethylene, propylene, vinyl acetate, alkyl acrylate, maleic anhydride, alpha-olefin.
12. The method according to any one of the preceding claims, characterized in that the particles (7) containing the third thermoplastic polymer have an average particle size of less than or equal to 1000 pm, and / or that the particles (17) containing the fourth thermoplastic polymer have an average particle size of between 80 and 800 pm, preferably between 100 and 500 pm, wherein for the particles (17) containing the fourth thermoplastic polymer, particle sizes that are as uniform as possible, in particular with size differences of less than a factor of 3, are particularly preferred.
13. Method according to one of the preceding claims, characterized in that the particles (7, 17) have a surface weight between 1 g and 20 g per m 2 , preferably between 3 g and 5 g per m 2 , are applied to the substrate (3) and / or the nonwoven material (4).
14. Method according to one of the preceding claims, characterized in that the particles (7, 17) are set to a temperature above their softening temperature when bonding to the substrate (3) or the nonwoven material (4).
15. Method according to one of claims 1 to 3 and 5 to 14, characterized in that the web-shaped substrate (3) is a flat web and the web-shaped composite material (2) is formed from the substrate (3) and the nonwoven material (4) into a tube (15) by placing the side regions (2a, 2b) of the flat, web-shaped composite material (2) on top of one another and connecting them to one another to form an overlap (2c), the nonwoven material (4) forming an inner layer of the tube (15).
16. Method according to one of the preceding claims, characterized in that the hose (15) produced according to claim 15 or a composite material (2) comprising the tubular substrate (3) according to claim 4 is separated into hose pieces and a base is formed on at least one end of the hose pieces.
17. Device (1, 20) for producing a flexible web-shaped composite material (2), comprising Feeding means for feeding a web-shaped substrate (3) which at least partially contains a first thermoplastic polymer, Feeding means for feeding a web-shaped nonwoven material (4) which at least partially contains a second thermoplastic polymer, a device for applying discrete particles (7) which contain a third thermoplastic polymer to the web-shaped substrate (3) or to the web-shaped nonwoven material (4), wherein the device for applying particles (7) comprises 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), wherein the release surface (6) can be heated to a temperature which is above a softening temperature of the third thermoplastic polymer, a pair of rollers (9) for bringing a surface (3a, 4a) of the substrate (3) or of the nonwoven material (4) into contact with the release surface (6) and the softened particles (7) arranged thereon, so that the particles (7) are adhered to the surface (3a, 4a) of the substrate (3) or of the nonwoven material (4),and optionally comprises a cooling means (10) for cooling the particles (7) adhering to the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) below the softening temperature of the third thermoplastic polymer, characterized in that the device (1, 20) further comprises: Means (21) for bringing together the substrate (3) and the nonwoven material (4) such that the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) with the particles (7) adhering thereto faces a surface (4a, 3a) of the nonwoven material (4) or the substrate (3), optionally a heating device (11) for heating the particles (7) adhering to the surface (3a, 4a) of the substrate (3) or the nonwoven material (4) above the softening temperature of the third thermoplastic polymer, and a pair of rollers (12) for pressing the substrate (3) and the nonwoven material (4) together, so that the softened particles (7) contact the mutually facing surfaces (3a, 4a) of the substrate (3) and the nonwoven material (4) together, and optionally coolant (14) for cooling the composite material (2) thus produced from the substrate (3) and the nonwoven material (4).
18. Apparatus according to claim 17, characterized by a device for applying discrete particles (17) containing a fourth thermoplastic polymer to the web-shaped substrate (3), wherein the device for applying particles (17) comprises a heatable release surface (6, 16), a container (18) from which a plurality of the discrete particles (17) can be applied to the release surface (6, 16), wherein the release surface (6, 16) can be heated to a temperature which is above a softening temperature of the fourth thermoplastic polymer, a pair of rollers (19) for bringing a surface (3b) of the substrate (3) into contact with the release surface (6, 16) and the softened particles (17) arranged thereon, so that the particles (17) adhere to the surface (3b) of the substrate (3), and optionally a coolant (14) for cooling the particles (17) arranged on the surface (3b) of the substrate (3) adhering particles (17) below the softening temperature of the fourth thermoplastic polymer.
19. Device according to claim 18, characterized by a turning device (30) for turning the substrate (3) or the composite (2) of the substrate (3) and the nonwoven material (4) prior to applying the particles (17) containing a fourth thermoplastic polymer to the surface (3b) of the substrate (3) opposite the nonwoven material (4) and means for feeding the turned composite (2) to the release surface (6), which also serves to apply the particles (7) containing a third thermoplastic polymer, so that the surface (3b) of the substrate (3) opposite the nonwoven material (4) faces the release surface (6).