Adhesive seam, method and device for joining multi-layer material coils or multi-layer material sheets with heat-activated adhesive, and use of impact press

Abstract

The invention relates to an adhesive seam, to a method and to a device for joining a multi-layer web (10) of material by means of a heat-activated adhesive, in particular a hot-melt adhesive (11), wherein the web (10) of material is joined between impact elements (2, 4) along the adhesive seam (12). According to the invention, an impact pulse is applied to a multi-layer web or sheet (10) of material arranged one above the other between a pair of unheated impact elements (2, 4), an adhesive (11) being located between the multi-layer web or sheet (10) of material. The adhesive seam (12) is formed by means of the impact pulse, the impact pulse at least partially penetrating the adhesive (11) and thereby activating the adhesive, the activation being limited to an extended region of the adhesive seam (12), and the height of the adhesive seam (12) formed being less than the height of two layers of material web or sheet (10), and wherein all liquefied adhesive (11) participates in the formation of the seam (12), and the area of the liquefied adhesive (11) remains limited to the seam (12). The invention also relates to the use of the impact press.

Description

[0001] The present invention relates to a bonding seam for joining multilayer material webs or sheets using a heat-activated adhesive, in particular a hot-melt adhesive. The multilayer material webs or sheets consist in particular of non-sealable materials such as paper, metal, or fabric, wherein shaped multilayer material webs or sheets or sections thereof are also encompassed by the invention, for example, sections of multilayer material webs or sheets that have been shaped into packaging. The invention also relates to a method and a device for joining multilayer material webs or sheets using a heat-activated adhesive, wherein the multilayer material webs or sheets are joined along the bonding seam, and to the use of an impact press.

[0002] The important application field that is used for joining by heat-activated adhesive as a whole is the production and sealing of packaging, wherein hot melt adhesive (also referred to as molten adhesive, hot melt, hot glue or hot melt) can seal quickly, for example in a box, for example as outer packaging or collective packaging. The adhesive melts when heated, and thus it is activated for overall joining. After being applied to the bonding area, the adhesive cools and hardens in a short time. Once the adhesive solidifies, the adhesive joint can be loaded immediately. The shortcoming is that it is very difficult to remove the hot melt adhesive sprayed during cleaning equipment. In addition, hot melt adhesive can only be used for relatively large, stable objects, because after applying, enough contact pressure is needed to obtain a firm adhesive joint. The hot melt adhesive that is directly applied is particularly not suitable for flexible materials and very small bonding areas.

[0003] In order to avoid the disadvantages associated with applying hot melt adhesive during bonding, hot melt adhesive can be applied in advance to the entire surface or only in the subsequent bonding area. Such solutions are known in various embodiments, of which the publication DE 10 2019 112 788 A1 is cited as an example. Therein, a device and method for coating a multilayer material roll or multilayer material sheet, in particular a paper roll or paper sheet, with a hot melt adhesive is described. In this case, the hot melt adhesive is applied in strips only where bonding is to be performed later. The multilayer material roll or multilayer material sheet prepared in this way is then suitable for processing and bonding in known heat sealing processes. For this purpose, the required heat is introduced into the sealing area of ​​the material to bond the coated material roll to another layer of the material.

[0004] Heat sealing refers to thermal bonding using heated welding elements (also called sealing elements). Methods and devices for heat sealing are described in publications DE 10 2011 080 462 A1 and DE 10 2016 218 190 A1. Numerous efforts are underway to eliminate heated welding elements. This is primarily for two reasons: to safely package heat-sensitive items while avoiding heat input and to reduce energy consumption.

[0005] Thermal bonding using ultrasound eliminates the need for heated impact elements, as the thermal effect in the films to be bonded is generated by the energy input of the ultrasonic vibrations themselves. This effect is the basis for ultrasonic sealing solutions combined with heat sealing, as described in publications DE 699 26 758 T2, DE 10 2009 046 319 A1, and DE 10 2017 121 572 A1. However, the mechanical equipment required for ultrasonic sealing and the generation of ultrasonic waves is very complex.

[0006] Heat input can also be avoided by using cold-sealable polymer dispersions, as proposed in publication WO 2011 / 003864 A1. However, a special polymer dispersion must be applied to the joint.

[0007] Other methods for processing multilayer material coils or sheets, such as separating them by impact pulses using a foil punch according to publication DE 10201 5 211 622 A1, are also not suitable for joining hotmelt adhesive-coated multilayer material coils or sheets together and forming an adhesive or sealed seam.

[0008] The object of the present invention is therefore to provide a method for joining a bonded seam of multi-layer material webs or sheets (e.g. made of paper and metal or fabric) by means of a heat-activated adhesive, and furthermore to provide a reliable, simple method for joining a multi-layer material web or sheet along a bonded seam by means of a heat-activated adhesive. A further object of the present invention is to provide an energy-saving and simple device for joining a multi-layer material web or sheet along a bonded seam by means of a heat-activated adhesive, and the use of an impact press.

[0009] This problem is solved by a bonded seam for joining multi-layer material webs or sheets (e.g., made of paper, paper-based materials, and metal or fabric), wherein the bonded seam is formed using a heat-activated adhesive that materially joins the multi-layer material webs or sheets. According to the invention, a shock pulse is applied to the multi-layer material webs or sheets, wherein the layers of the material webs or sheets are arranged one above the other between a pair of unheated impact elements, with adhesive located between the layers of the material webs or sheets. This is manifested by an impact motion of at least one of the impact elements perpendicular to the multi-layer material webs or sheets, wherein the penetration of at least one of the impact elements into the multi-layer material webs or sheets lasts less than 10 milliseconds, thereby forming the bonded seam. The bonded seam is formed by the shock pulse penetrating and deforming the adhesive. During the deformation, heat is generated in the adhesive, causing the adhesive to be thermally activated, with the thermal activation being limited to the region of the bonded seam, particularly its horizontal extent.

[0010] The application of the shock pulse also results in the height of the adhesive seam being smaller than the height of two material rolls or sheets arranged one above the other and joined together by the adhesive seam.The shock pulse also causes deformation of the multi-layer material roll or sheet.

[0011] During the formation of the bonded seam, all liquefied adhesive participates in its formation, and the area of ​​liquefied adhesive remains confined to the bonded seam. Thus, in contrast to heat sealing, adhesive does not escape from the bonded seam area, and thus, no adverse deformations along the bonded seam occur. The result is a higher-quality bonded seam and more efficient use of adhesive, as it can be applied thinner and therefore in smaller quantities. The bonded seams produced by the impact pulse according to the present invention are characterized by the avoidance of adhesive discharge, or the confinement of liquefied adhesive to the bonded seam, as well as by the compression of the seam.

[0012] It has proven to be advantageous if the impact pulse penetrates at least 50% into the adhesive, ie at least 50% of the adhesive must be deformed.

[0013] The effect of the impact pulse occurs between the unheated impact elements. In any case, it is not necessary to heat the impact elements; in fact, this is even disadvantageous, especially if such heating (as an external heat supply) leads to premature softening of the adhesive. Therefore, preheating of the multilayer material coil or multilayer material sheet is also excluded. Therefore, "unheated" should be understood as meaning that the temperature of the impact element and the multilayer material coil or multilayer material sheet is below the softening temperature of the adhesive. If, for other reasons, the impact element or the multilayer material coil / sheet is slightly heated, this has no effect on the method according to the invention, and within the meaning of the invention, the impact element and the multilayer material coil / sheet are considered to be unheated or not preheated. If a pair of (unheated) impact elements is an unequal pair and one impact element is working against a flat, non-forming anvil, then there is also a pair of (unheated) impact elements, which anvil then forms the second impact element of the pair of impact elements within the meaning of the invention.

[0014] The impact pulse is an impact movement of at least one of the impact elements substantially perpendicular to the multilayer material web or sheet, wherein the penetration of at least one of the impact elements into the multilayer material web or sheet (with the adhesive therebetween) lasts less than 10 ms. Preferably, the penetration lasts less than 5 ms, particularly preferably less than 1 ms, and, depending on the film thickness, between 0.05 ms and 0.5 ms. To this end, for the impact pulse, the tool is preferably dropped onto the assembly of the multilayer material web or sheet with the adhesive at an initial speed of 1 m / s to 5 m / s and decelerates to a standstill during the penetration, releasing and converting kinetic energy. As the kinetic energy of the impact pulse is converted, the adhesive is particularly deformed and thereby heated. The impact pulse is preferably generated by a mechanical drive or an electromagnetic drive.

[0015] According to a first alternative, the heat-activated adhesive is applied to at least one layer of the multilayer material web or sheet, at least in the region of the adhesive seam or over the entire surface. Full-surface application is accompanied by greater flexibility in the location of the adhesive seam, but also by a higher material usage of the adhesive and more complex recycling.

[0016] According to a second alternative, before the impact pulse is applied, the heat-activated adhesive is placed in at least the region of the bond seam to be produced between the multi-layer material webs or sheets, without bonding to one of the layers of the multi-layer material webs or sheets. In a web-guided process, for example, the adhesive strip can be supplied from a roll between the multi-layer material webs or sheets.

[0017] One advantageous embodiment or application is to join the material rolls or sheets in the region of the previously folded-over opposing edges by means of an adhesive seam, which forms a longitudinal seam. This creates a tube. Thus, multiple layers of material rolls or sheets arranged one above the other can also be a single folded-over material roll or sheet.

[0018] According to another embodiment, the tube is transformed into a tubular bag by at least one additional adhesive seam, which forms a transverse seam and seals the previously formed tube at at least one end with a bottom seam. To close the tubular bag, the opening is also provided with a transverse seam, i.e., a top seam. Multilayer tubular bags can also be produced in this way by feeding more layers during the tube formation process.

[0019] It has been shown that the impact pulse produces an embossing in the multi-layer material web or sheet in the region of the bond seam. This embossing is formed by the impact of the impact element onto the multi-layer material web or sheet according to the contour of the impact element. This effect can be used for further applications, such as reinforcing the material, imprinting information, or creating an aesthetic design.

[0020] Preferably, the heat-activated adhesive is a hot melt adhesive, such as is commonly used in the packaging industry, and this is not unimportant. In this context, advantageous applications of the present invention involve multi-layer webs or sheets of paper or paper-based materials. These materials are also widely used in the packaging industry and rely on adhesive bonding when integral bonding is required.

[0021] The objects of the present invention are also achieved by a method for joining multi-layer material webs or sheets using a heat-activated adhesive, wherein the multi-layer material webs or sheets are joined along an adhesive seam. According to the present invention, an impact pulse is applied to a multi-layer material web or sheet positioned one above the other between a pair of unheated impact elements, wherein at least one impact element extends perpendicularly to the impact motion of the multi-layer material web or sheet. Heating the impact elements is not necessary; on the contrary, this is disadvantageous, particularly if such heating (as an external heat supply) causes softening of the material web or sheet. Therefore, preheating the material web or sheet is also precluded. Therefore, "unheated" should be understood to mean that the temperature of the impact element and the material web or sheet remains below the softening temperature of the material web or sheet. If the impact element or material web / sheet is slightly heated for other reasons, this has no effect on the method according to the present invention, and within the meaning of the present invention, the impact element or material web / sheet is considered to be unheated or not preheated.

[0022] Due to the rapid temperature increase, the material temperature has little effect, provided no harmful softening of the material occurs due to excessively high temperatures. This also applies to impact elements that do not require preheating, as the temperature required for bonding is generated very quickly during the impulse, within the multilayer material coil or sheet or within the adhesive itself. Consequently, heating and melting of the adhesive are advantageously limited to the immediate active area and the short contact time. Due to the high deformation speed, adiabatic heating of the adhesive and / or material coil or sheet occurs in the active zone with minimal energy input, without heat exchange with the surrounding air or adjacent areas of the material coil or sheet and adhesive. Only the amount of adhesive required for the joint is liquefied. This also prevents liquid adhesive from escaping from the joint area or active zone and from participating in the formation of the bonded seam.

[0023] The bond seams are preferably produced very narrow, which results in, among other things, material savings. Furthermore, time is saved and energy input is reduced. Such narrow bond seams or such narrow heat-affected zones cannot be achieved using conventional heat sealing processes for activating adhesives, as the heat would dissipate too quickly and the heated and softened area in the material web or sheet would therefore expand.

[0024] The impact pulse acts with a duration of less than 10 milliseconds, causing at least one of the impact elements to penetrate the multi-layer material web or sheet and the adhesive therebetween. It is advantageous if at least 50% of the adhesive deforms during the impact pulse. This activates the adhesive and forms a bonded seam. This is followed by an immediate return stroke of the at least one impact element, releasing the material web or sheet with the formed bonded seam.

[0025] In a step prior to the impact pulse, the multi-layer material roll or multi-layer material sheet and adhesive are tensioned between a pair of impact elements with a pre-tensioning force F v The multi-layer material web or sheet is pressed against each other. Thereafter, the impact pulse of at least one of the driven impact elements (or the impact pulse transmitted by at least one of the impact elements) acts on the multi-layer material web or sheet and the adhesive. Thus, as an alternative to directly dropping the tool onto the material web or sheet, roughness of the tool surface, in particular of the multi-layer material web or sheet arranged one above the other, is initially partially compensated by the adhesive. In each case, a temperature effect occurs in the active zone (i.e., the developing adhesive seam), which leads to localized, extremely short-term melting of the adhesive during the penetration period at a correspondingly high deformation rate, as well as mechanical loading during the penetration period.

[0026] In the transmission of the shock pulse, particularly through the impact element, the speed of sound and a shock pulse duration of less than 10 ms, preferably 5 ms, are assumed. For a steel / steel pulse, a duration of 0.25 ms is calculated for a distance of 10 cm. Using shock pulses, comparable results to ultrasonic sealing are achieved on comparable materials; however, only a single pulse, the shock pulse according to the invention, is applied instead of a large number of low-amplitude pulses as in ultrasonic sealing. In both processes, when using ultrasound and shock pulses, the temperature increase required for thermal bonding is achieved through physico-chemical effects in the adhesive. At the same time, further advantages are achieved, notably the absence of heat input and, therefore, thermal protection of the packaged product, which is also crucial for using ultrasonic sealing, without the need for complex equipment technology with ultrasound generation and welding heads.

[0027] The melting of the adhesive remains confined to the active area. Thus, surrounding areas are neither affected by undesirable heat input (e.g. areas around adhesive seams in webs or sheets of material or packaging products) nor dissipated as energy loss to surrounding areas.

[0028] The impact pulse is preferably generated by a mechanical or magnetic drive, with the impact element being driven directly, or indirectly via a spring force, a drop weight, a magnetic drive, or a cam drive. The cam drive allows particularly fast movements to be controlled without delay and with precise amplitudes. In particular, the spring force and the drop weight can be manually brought into their force-generating position, allowing the method according to the invention to be performed without an external energy supply.

[0029] The impact pulse is applied by an upper impact element or by two impact elements facing each other. In particular, with impact elements facing each other, these impact elements can also be used in high-speed processes (for example in tubular bag machines with, for example, 100 cycles per minute) and can be integrated therein. In this case, the impact element can be configured as a roller, which can also operate as a feed roller. The feed roller applies the pretensioning force F v , while the pulse force F i The impacts applied to the rollers are transmitted to the material web or sheet and the adhesive arranged between them.

[0030] According to a first alternative, a heat-activated adhesive is applied to at least one layer of the multilayer material web or sheet, at least in the region of the bond seam, and then bonded to the material web or sheet. According to a second alternative, a heat-activated adhesive is placed between the multilayer material webs or sheets, at least in the region where the bond seam is to be created, before the impact pulse is applied, wherein the heat-activated adhesive does not bond to either of the two multilayer material webs or sheets.

[0031] Furthermore, it has proven advantageous if the material coils or sheets are joined in the edge regions by adhesive seams, wherein the adhesive seams form longitudinal seams to produce tubes. Furthermore, the tubes can be closed by adhesive seams forming cross seams, thereby producing tubular bags.

[0032] According to an advantageous embodiment, a strip of heat-activated adhesive is supplied together with the web or sheet of material and is introduced or arranged between the overlapping edges of the web or sheet of material during the forming of the tube.

[0033] It has been shown that when an impact element strikes a multi-layer material web or sheet, an impression corresponding to the contour of the impact element is produced in the multi-layer material web or sheet. As described in more detail above, it has also proven advantageous when opposing impact elements are used in a continuous, high-speed process.

[0034] Preferably, the heat activated adhesive is a hot melt adhesive.Preferably, the multilayer material web or multilayer material sheet is made of paper or a paper based material which requires an adhesive for material bonding and which, unlike plastic films, cannot be welded.

[0035] Another advantageous alternative is a bonded seam designed as a bonding point, whereby multi-layered webs or sheets are joined via a plurality of such bonding points arranged in rows. This allows for the creation of any desired seam shape, each composed of multiple bonding points, without the need for a correspondingly shaped impact element. Furthermore, only low pulse energy is required for the small area of ​​bonding points, making the system compact and easy to implement without complex drives. To achieve broad flexibility, this approach is suitable for multi-layered webs / sheets completely covered with adhesive.

[0036] The object of the present invention is also achieved by a device for joining multi-layer material rolls or sheets along an adhesive seam using a heat-activated adhesive. According to the present invention, the device includes a pair of unheated impact elements. If one impact element is working against a base (flat anvil), there is also a pair of unheated impact elements, which then constitutes the second impact element of the pair of impact elements. The pair of unheated impact elements is arranged to receive multi-layer material rolls or sheets arranged one above the other, with adhesive arranged between them. In addition, it includes a device for generating pulses, which is configured to introduce a shock pulse into at least one of the impact elements in order to activate the adhesive. The shock pulse is an impact movement of at least one of the impact elements perpendicular to the multi-layer material roll or sheet, wherein the time to penetrate the multi-layer material roll or sheet and the adhesive is less than 10 milliseconds. The shock pulse acts on the multi-layer material roll or sheet and, by activating the adhesive, forms an adhesive seam in the active area of ​​the impact element. The shock pulse is preferably generated by a drive device.

[0037] According to an advantageous further development, a method for applying a pre-tensioning force (F v ) by which the impact element is pre-tensioned (F v ) press against each other.

[0038] In a preferred embodiment, the pair of impact elements includes at least a first impact element having an active area with a profiled cross section. It has also proven advantageous if the pair of impact elements includes a second impact element with a flat active area. Advantageous profile cross sections have a flat profile bounded by two radii R2, which can have any profile shape and a width a covering at least the area of ​​the adhesive seam. In a preferred embodiment, the profile cross section at the active location (which comes into contact with the multi-layer material web or sheet to be bonded during the bonding process or impact pulse) is formed as a flat profile bounded on both sides by two radii R2, preferably with R2 = 1 mm to 4 mm, and having a width a of at least a = 2 mm.

[0039] According to an advantageous embodiment, the first and / or second impact elements are designed as rolling tools for use in a continuous-feed web-guiding process, such as the high-speed process described in greater detail above. Alternatively, the first and / or second impact elements can be configured as tools that rotate toward a point of interest or as tools that temporarily follow the web during the gluing process, as is customary and well-known for specific process stages in web-guiding processes. The device according to the present invention is therefore suitable for installation in packaging systems, where established sealing technologies can also be replaced. Advantageously, the pair of impact elements are made of hardened steel with a ground surface. Furthermore, each impact element includes a means for attaching to a drive device.

[0040] According to a first embodiment, the drive acts on the first impact element, or according to a second embodiment, on both the first and second impact elements. The drive for generating the impact pulse preferably comprises a spring, a drop weight, or a mechanical gear. According to an advantageous embodiment, the mechanical gear is a cam drive, the advantages of which have already been explained above. Magnetic drives are also provided that directly drive the impact element or the associated punch.

[0041] A further aspect of the invention relates to the use of an impact press as a drive device for a device as described above for joining multi-layer material webs or sheets by means of a heat-activated adhesive.

[0042] Pneumatic impact presses are not only suitable for embossing metals, but also for marking plastics and similar products. Small impact presses are also frequently used in the pharmaceutical industry to emboss medicine boxes. Using springs, the desired impact force can be precisely set and adjusted, and consistent embossing results can be achieved in every embossing process with the same material. The pre-tensioning effect, which also plays a decisive role in the method according to the invention, allows precise positioning of the workpiece and prevents deformation. Different embossing tools (such as machine dies, machine type holders and embossing units) can be clamped into these machines via a clamping system. An exemplary embossing press has an impact force of 6 kN.

[0043] Compared to established sealing methods such as thermal contact sealing or ultrasonic sealing, the method proposed according to the invention offers the following advantages:

[0044] Cold tools, adiabatic joining process;

[0045] Use with heat-sensitive products;

[0046] Very cost-effective and reliable system and tool technology;

[0047] Possibility of implementing purely mechanical and manually operated solutions (spring pre-tensioning);

[0048] Extremely short process time;

[0049] Minimum seam width can be achieved;

[0050] Specific seams and embossing patterns can be obtained by using contour patterns on the tool;

[0051] Can implement traditional packaging forms (side-sealed bags, tubular bags);

[0052] Very low energy requirements, resulting in very high energy efficiency.

[0053] For comparison, thermal pulse joining of material coils or sheets with a thickness of 20 to 100 μm and a typical seam length requires an electrically generated heat pulse of 0.8 seconds at 165°C. When using sealing jaws, this corresponds to an energy consumption of 200 J. In contrast, joining using the method according to the present invention requires only 5 J of energy for the same seam length. This represents an energy saving of 97.5%.

[0054] The above advantages lead to the following favorable application areas:

[0055] Packaging processes using multi-layer material rolls or sheets (for technical products, food, medical products) for both high-speed serial applications and individual processes in decentralized production;

[0056] Used in continuous processes due to high process speeds;

[0057] Suitable for recyclable and compostable films;

[0058] For use in spring-pretensioned, energy-free seals for mobile use, medical technology for development aid (packaging of medical samples on site), disaster relief (sealing of sandbags);

[0059] Packaging in dusty environments

[0060] The invention is explained in more detail below based on the description of exemplary embodiments and their illustration in the associated drawings. The drawings show:

[0061] Figure 1 : A schematic diagram of the process sequence of the method for joining a multi-layer material roll or a multi-layer material sheet by thermal joining according to the present invention;

[0062] Figure 2 : A schematic perspective view of an embodiment of an impact element according to the invention, wherein the active region has a flat profile cross section delimited by two radii;

[0063] Figure 3 : A schematic perspective view of an embodiment of a first impact element according to the invention, the first impact element having an active area with a flat profile cross section;

[0064] Figure 4 : A schematic perspective view of an embodiment of a second impact element according to the present invention, wherein the second impact element has a flat effective area;

[0065] Figure 5 : Two schematic diagrams of an embodiment of an impact press;

[0066] Figure 6 : Schematic side view of an embodiment of a continuous web-guided process;

[0067] Figure 7 : Two schematic diagrams of another embodiment of a continuous web guiding process;

[0068] Figure 8 : A schematic perspective view of an embodiment of a bonded seam on a pipe according to the present invention;

[0069] Figure 9 : A schematic perspective view of an embodiment of a bonded seam on a tubular bag according to the present invention;

[0070] Figure 10 : A schematic side view of an embodiment of a device according to the invention with joined material webs or sheets;

[0071] Figure 11: Schematic enlarged view of the joint location of a multi-layer material roll or multi-layer material sheet with a joint.

[0072] Figure 1 A diagram schematically illustrates an embodiment of the process sequence of the method according to the invention for joining multi-layer material webs / sheets 10 using impact pulses with a heat-activated adhesive 11. Starting from the left, the process sequence is shown in three steps. First, the first impact element 2 is advanced in the direction of the arrow along a feed path S. z The active contour 6 is moved to the surface of the multilayer material web / sheet 10 until it contacts the multilayer material web / sheet 10, with the adhesive to be activated (i.e., hot melt adhesive 11) being arranged between the material webs / sheets 10. The two multilayer material webs / sheets 10 to be joined by the adhesive seam 12 rest on the surface of the second impact element 4, which in this case is configured as a flat anvil. The active contour 6 is also flat and tapers to a radius in order not to damage the material webs / sheets 10.

[0073] In the second step, the pre-tensioning force F v The first impact element 2 is pressed against the multilayer material web or sheet 10, with the hot melt adhesive 11 positioned between the multilayer material web or sheet 10. Under the preload thus generated, which compensates for the surface roughness and elasticity of the material structure, the impulse force F applied in the third step i , resulting in activation of the hot-melt adhesive 11 , which briefly melts in the active area, thereby forming the adhesive seam 12 .

[0074] Figure 2 A perspective view schematically shows an embodiment of an impact element 2 according to the invention having a flat profile cross section tapering to two radii R2 and forming an effective profile 6, as shown in FIG. Figure 1 In the exemplary effective profile 6 , the preferred radius R2 is 1 mm to 4 mm, and the flat profile has a width of at least a=2 mm.

[0075] Figure 3 A perspective view schematically shows an embodiment of a first impact element 2 according to the present invention, wherein the first impact element 2 has an active region 6 having a flat profile cross section, such as Figure 2 The mounting opening 8 is used to receive a clamping bolt (not shown here), by means of which the first impact element 2 is fastened to the impact element holder 26 of the machine (see Figure 5 ), the machine will pre-tension F v and pulse force F i Applied to the first impact element 2 .

[0076] Figure 4 A perspective view of an embodiment of a second striking element 4 according to the invention is schematically shown, which has a flat, anvil-shaped active area 6. The second striking element 4 is fastened to a striking element holder 28 (see Figure 5 ).

[0077] Figure 5 Two views schematically illustrate an embodiment of an impact press 20 with which the method according to the invention can be carried out. It is particularly advantageous that such an impact press 20 can be operated without electrical power and purely manually, in particular as a spring-loaded impact press according to the illustrated embodiment. z The force required for the feed motion and the pretensioning force F v and impulse force F i Applied by the operator via the operating lever 24 .

[0078] like Figure 1 As shown, a bonded seam 12 is produced between the second impact element 4 and the first impact element 2 , the multi-layer material web / sheet 10 resting on the second impact element 4 , and the first impact element 2 being fastened to the first impact element holder 26 . For this purpose, the operating lever 24 is actuated and the first impact element holder 26 is moved via the feed device 32 toward the second impact element holder 28 until the first impact element 2 inserted into the first impact element holder 26 contacts the material web or sheet 10 .

[0079] By further moving the operating rod 24, the required pretensioning force F is applied. v And by further movement of the operating rod 24, during which the spring is tensioned, the pulse generator 30 is triggered to generate the pulse force F i is applied to the material web or sheet 10. Thus, an adhesive seam 12 is produced in the region of the contact zone between the first impact element 2 and the second impact element 4. By reversing the movement of the operating lever 24 and returning the second impact element holder 26, the sealed, bonded multilayer material web or sheet 10 is released.

[0080] Figure 6An embodiment of a continuous web-guiding process is schematically shown in side view, wherein a material web or sheet 10 is unwound from a web roll 40. In an apparatus 1 for joining multi-layer material webs / sheets 10 by gluing, the multi-layer material web / sheet 10 passes between a first impact element 2 and a second impact element 4, where a bonded seam 12 is produced (in the illustration, the bonded seam 12 has not yet been formed). However, precautions must be taken to ensure the continuity of the web-guiding process, even during the application of pretensioning forces, particularly during impact pulses. This can be achieved, for example, by cyclically moving and returning the apparatus 1 in or against the web-guiding direction, or by providing a web accumulator at the front of the apparatus 1 (both not shown but known from the prior art).

[0081] Figure 7 A schematic side view of another embodiment of a continuous web-guided process is shown. Pretensioning is applied by pretensioning rollers 42, between which the multilayer material web / sheet 10 passes. A pulse generating device 30, in particular an impact mechanism, acts on one or both pretensioning rollers 42, thereby producing a bonded seam 12.

[0082] Figure 8 Schematically shown is a perspective view of an embodiment of an adhesive seam 12 according to the invention on a tube 14 formed from folded and joined sections of a material web 10. The tube 14 can advantageously be used as a sleeve packaging, wherein it is pushed onto a further finished packaging.

[0083] Figure 9 A perspective view of an embodiment of an additional adhesive seam 12 according to the invention is schematically shown, here on a tubular bag 16. This includes, for example Figure 8 The tube 14 shown is closed at both ends with a transverse seam. This is usually done on the second side (usually the top side) after filling the packaged product. The bottom seam of the next tubular bag 16, i.e. the lower adhesive seam 12, can be produced at the same time.

[0084] Figure 10 Schematically shown is a side view of an embodiment of a device 1 according to the invention during bonding of a multi-layer material web / sheet 10 by forming a bonding seam 12. Figure 11 The device 1 comprises the impact elements 2 , 4 shown after the return stroke, which releases the adhesive seam 12 .

[0085] Figure 11Schematically, an enlarged view of a bonded joint is shown, specifically a bonded seam 12 with connected multilayer material webs / sheets 10, wherein the multilayer material webs / sheets 10 extend on both sides of the bonded seam 12. Visible is the very low bonded seam 12 in the active area, as well as the hot melt adhesive 11 fused to the multilayer material webs / sheets 10. The compression is also partly due to the fact that the multilayer material webs / sheets 10 consist of a compressible or heat-sensitive material, the height of which is also reduced by the shock pulse.

[0086] The hot-melt adhesive 11 protrudes undeformed next to the bond seam 12 and does not thicken as occurs in other heat sealing processes according to the prior art (in which liquid adhesive is squeezed out). This clearly shows that no excess adhesive 11 melts and shifts. Instead, the heat-affected zone 13—the boundaries of which with the unaffected multilayer material web / sheet 10 (and with the hot-melt adhesive 11, insofar as it protrudes beyond the activated zone in the region of the bond seam) are indicated by dashed lines—is limited to the region of the bond seam 12, and no area of ​​the multilayer material web / sheet 10 or any area outside of the multilayer material web / sheet 10 (e.g., the packaged product inside the package) is affected by the undesired heating.

[0087] Reference Signs List

[0088] 1 device

[0089] 2 First impact element

[0090] 4 Second impact element

[0091] 6 Effective range and effective profile

[0092] 8 Mounting opening

[0093] 10 Material rolls / sheets

[0094] 11 Adhesives, heat-activated adhesives, hot-melt adhesives

[0095] 12 Bonded seams, longitudinal seams, transverse seams

[0096] 13 Heat-affected zone

[0097] 14 Pipes

[0098] 16 Tubular Bags

[0099] 20 Impact press

[0100] 22 Stand

[0101] 24 joystick

[0102] 26 First impact element retainer

[0103] 28 Second impact element retainer

[0104] 30 (device for) generating pulses

[0105] 32 Feeding device

[0106] 40 Coil Roll

[0107] 42 Rolling tools, pre-tensioning rollers

[0108] a Effective profile width

[0109] R1 First effective contour radius

[0110] R2 Second effective contour radius

[0111] R3 third effective contour radius

[0112] F v Pretension

[0113] F i Pulse force and shock pulse strength

[0114] S z Feed path

Claims

1. A bonded seam for joining multi-layer material rolls or sheets (10) by means of a heat-activated adhesive (11), characterized in that An impact pulse acts vertically on multi-layer material rolls or sheets (10) arranged one above the other in the form of an impact movement of at least one of a pair of unheated impact elements (2, 4), with an adhesive (11) located between the multi-layer material rolls or sheets (10), wherein the time for at least one of the impact elements (2, 4) to penetrate the multi-layer material rolls or sheets (10) is less than 10 ms, wherein the adhesive seam (12) is formed by the impact pulse at least partially penetrating into the adhesive (11) and thermally activating the adhesive (11), wherein the thermal activation is limited to the area of ​​the adhesive seam (12), wherein the height of the adhesive seam (12) thus formed is less than the height of the two material rolls or sheets (10), and wherein all the liquefied adhesive (11) participates in the formation of the adhesive seam (12), and the area of ​​the liquefied adhesive (11) remains limited to the adhesive seam (12).

2. The bonded seam according to claim 1, wherein The heat-activated adhesive (11) is applied to at least one layer of the multi-layer material web or sheet (10), at least in the region of the adhesive seam (12).

3. The bonded seam according to claim 1 or 2, wherein: Before applying the shock pulse, the heat-activated adhesive (11) is arranged between the multiple layers of the material web or sheet (10) without being connected to the multiple layers of the material web or sheet (10), at least in the area of ​​the adhesive seam (12) to be produced.

4. A bonded seam according to any one of the preceding claims, wherein The material rolls or the material sheets (10) are joined in the region of the edges by the adhesive seams (12), which form a longitudinal seam, thereby forming a tube (14).

5. A bonded seam according to any one of the preceding claims, wherein The tube (14) is closed by means of a bonded seam (12) forming a transverse seam to produce a tubular bag (16).

6. A bonded seam according to any one of the preceding claims, wherein The heat-activated adhesive (11) is a hot melt adhesive.

7. A bonded seam according to any one of the preceding claims, wherein The multi-layer material roll or multi-layer material sheet (10) consists of paper or paper-based material.

8. A method for joining a plurality of material webs or sheets (10) by means of a heat-activated adhesive (11), wherein the plurality of material webs or sheets (10) are joined along an adhesive seam (12), characterized in that The invention relates to a method for producing a shock pulse as an impact movement of at least one of a pair of unheated impact elements (2, 4) arranged one above the other, which impact pulse acts vertically on the multi-layer material web or multi-layer material sheet (10), wherein the time for at least one of the impact elements (2, 4) to penetrate the multi-layer material web or multi-layer material sheet (10) and the adhesive (11) is less than 10 ms, by which the adhesive (11) is activated and the adhesive seam (12) is formed, followed by a return stroke of at least one of the impact elements (2, 4).

9. The method according to claim 8, wherein In a step prior to the impact pulse, the plurality of layers of the material roll or sheet (10) and the adhesive (11) are placed between the pair of impact elements (2, 4) with a pre-tensioning force F v Pressed against each other, and thereafter, an impact pulse of at least one of the driven impact elements (2, 4) or an impact pulse transmitted by at least one of the impact elements (2, 4) acts on the multiple layers of the material web or sheet (10) and the adhesive (11).

10. The method according to claim 8 or 9, wherein: The mechanical drive of the impact element (2, 4) is realized directly, or the impact pulse is transmitted indirectly by a spring force, a drop weight, a magnetic drive or a cam plate transmission mechanism.

11. The method according to any one of claims 8 to 10, wherein The impact pulse is applied via the upper impact element (2) or via two impact elements (2, 4) acting oppositely.

12. The method according to any one of claims 8 to 11, wherein Prior to application of the shock pulse, the heat-activated adhesive (11) is arranged between the plurality of webs or sheets (10) of material at least in the region where the bonded seam (12) is to be produced.

13. The method according to any one of claims 8 to 12, wherein The heat-activated adhesive (11) is applied to at least one layer of the multi-layer material web or sheet (10), at least in the region of the adhesive seam (12).

14. The method according to any one of claims 8 to 13, wherein The material rolls or sheets (10) are joined in the edge regions by the adhesive seams (12) forming the longitudinal seams, thereby forming a tube (14).

15. The method according to claim 14, wherein During formation of the tube (14) from the material coil or sheet, a strip of adhesive (11) is supplied with the material coil or sheet and is arranged between overlapping edges of the material coil or sheet.

16. The method according to any one of claims 8 to 15, wherein The tube (14) is closed by a bonded seam (12) forming a transverse seam, thereby producing a tubular bag (16).

17. The method according to claim 16, wherein The opposed impact elements (2, 4) are used for a continuous, high-speed process.

18. The method according to any one of claims 8 to 17, wherein The heat-activated adhesive (11) is a hot melt adhesive.

19. The method according to any one of claims 8 to 18, wherein The multi-layer material roll or multi-layer material sheet consists of paper or paper-based material.

20. A device for joining a roll or sheet of multilayer material (10) along an adhesive seam (12) by means of a heat-activated adhesive (11), characterised in that The device (1) comprises a pair of unheated impact elements (2, 4), the impact elements (2, 4) being configured to receive multiple layers of the material rolls or sheets (10) arranged one above the other, with the adhesive (11) between the multiple layers of the material rolls or sheets (10), wherein the device (30) for generating a pulse is arranged to introduce the impact pulse into at least one of the impact elements (2, 4) to activate the adhesive (11), wherein the impact pulse represents an impact movement of at least one of the impact elements (2, 4) extending perpendicularly to the film layer, wherein the time for at least one of the impact elements (2, 4) to penetrate the multiple layers of the material rolls or sheets (10) and the adhesive (11) is less than 10 ms, wherein the impact pulse acts on the multiple layers of the material rolls or sheets (10) and forms the adhesive seam (12) in the effective area of ​​the impact elements (2, 4) by activating the adhesive (11).

21. The device according to claim 20, wherein For applying pre-tensioning force (F v ) is applied before the shock pulse is applied by the pre-tensioning force (F v ) presses the impact elements (2, 4) against each other.

22. The device according to claim 20 or 21, wherein The profile cross section (6) is formed as a flat profile delimited by two radii R2, with a width a covering at least the area of ​​the adhesive seam (12).

23. The device according to any one of claims 20 to 22, wherein The first impact element and / or the second impact element (2, 4) are designed for a coil guiding process with continuous feed.

24. The device according to claim 23, wherein The first impact element and / or the second impact element (2, 4) is designed as a rolling tool (42), as a tool that pivots toward the active area, or as a tool that moves with the web during the bonding process.

25. The device according to any one of claims 20 to 24, wherein The means (30) for generating a pulse comprises a spring, a falling weight or a mechanical gear.

26. Use of an impact press (20) as a drive device for a device according to any one of claims 20 to 25.

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