Bonded seam, method, and device for joining material webs or material sheets by means of a thermally activatable adhesive, and use of an impact press

Abstract

The invention relates to a bonded seam, a method, and a device for joining material webs (10) by means of a thermally activatable adhesive, in particular a hot-melt adhesive (11), wherein the material webs (10) are joined between impact elements (2, 4) along a bonded seam (12). According to the invention, an impact pulse is applied to the material webs or material sheets (10) which are arranged one above the other between a pair of unheated impact elements (2, 4) and between which the adhesive (11) is located. By means of this process, the bonded seam (12) is formed by the impact pulse penetrating at least in part into the adhesive (11) and the adhesive being activated thereby, with the activation being limited to the region where the bonded seam (12) extends, and with a resulting height of the bonded seam (12) which is lower than the height of both material webs or material sheets (10), and with all the liquefied adhesive (11) being used in the formation of the bonded seam (12) and the region of the liquefied adhesive (11) remaining restricted to the bonded seam (12). The invention also relates to the use of an impact press.

Description

[0001] Adhesive seam, method and device for joining material webs or sheets by means of a thermally activated adhesive and use of an impact press

[0002] The invention relates to an adhesive seam for joining material webs or sheets using a thermally activatable adhesive, in particular a hot-melt adhesive. The material webs or sheets consist in particular of non-sealable materials such as paper, metal, or textile. The invention also encompasses formed material webs or sheets or sections thereof, for example, sections of material webs or sheets already formed into packaging. The invention further relates to a method and a device for joining material webs or sheets using a thermally activatable adhesive, wherein the material webs or sheets are joined along an adhesive seam, and also to the use of an impact press.

[0003] An important application for bonding, i.e. material-to-material joining, using a thermally activated adhesive is the manufacture and sealing of packaging, where a hot melt adhesive (also known as melt adhesive, hot melt glue, hot melt or hot glue) enables rapid sealing, for example of boxes as outer packaging or collective packaging. The adhesive melts when heated, which activates it for the material-to-material joining. After being applied to the bonding area, it cools down within a short time and hardens. As soon as the adhesive has cured, the bonding area can be subjected to load immediately. The disadvantage is that splashed hot glue is very difficult to remove when cleaning the equipment. In addition, hot glue can only be used on relatively large, stable objects, since sufficient contact pressure is required after application to achieve a strong adhesive bond.Directly applied hot melt adhesives are not suitable, especially for flexible materials and very small bonding areas.

[0004] In order to avoid the associated disadvantages of applying hot melt adhesive at the moment of bonding, the hot melt adhesive can be applied beforehand over the entire surface or exclusively in the later bonding area. Such solutions are known in a wide variety of designs, with document DE 10 2019 112 788 A1 being cited as an example. This document describes a device and a method for coating material webs or sheets, in particular a paper web or sheet, with hot melt adhesive. The hot melt adhesive is only applied in strips where bonding is to take place later. The material webs or sheets prepared in this way are then suitable for processing and bonding using a known heat sealing process. For this purpose, the coated material web is bonded to another layer of the material in a sealing zone in which the required heat is introduced into the material.

[0005] Heat sealing refers to thermal joining using heated sealing jaws, also known as sealing jaws. A method and device for heat sealing are described in the publications DE 10 2011 080 462 A1 and DE 10 2016 218 190 A1. There are numerous efforts to eliminate heated sealing jaws. Two main reasons for this are the secure packaging of heat-sensitive goods while avoiding the introduction of heat energy, and the reduction of energy consumption.

[0006] Thermal joining using ultrasound eliminates the need for heated impact jaws, as the thermal effect in the films to be joined is generated by the energy input of the ultrasonic vibrations. Ultrasonic sealing solutions, described in publications DE 699 26 758 T2, DE 10 2009 046 319 A1, and DE 10 2017 121 572 A1, are based on this effect, as described in, for example, DE 699 26 758 T2, DE 10 2009 046 319 A1, and DE 10 2017 121 572 A1, here in combination with heat sealing. However, the mechanical equipment required for ultrasonic sealing and the generation of the ultrasound are very complex.

[0007] Heat input can also be avoided by using a cold-sealable polymer dispersion, as proposed in WO 2011 / 003864 A1. However, this special polymer dispersion must be applied at the joint.

[0008] Other methods for processing material webs or sheets, such as separating the material web or sheet by means of an impact pulse using a foil punch according to the document DE 10 2015 211 622 A1, are also not suitable for joining hot-melt adhesive-coated material webs or sheets to one another and forming an adhesive or sealed seam.

[0009] It is therefore the object of the present invention to provide an adhesive seam for joining material webs or sheets, e.g., made of paper, but also of metal or textile, using a thermally activated adhesive, and to provide a robust, inexpensive method for joining material webs or sheets using a thermally activated adhesive along an adhesive seam. Further objects of the invention include an energy-saving and simple device for joining material webs or sheets using a thermally activated adhesive along an adhesive seam, as well as the use of an impact press.

[0010] The problem is solved by an adhesive seam for joining material webs or sheets, e.g. made of paper, paper-based materials, but also of metal or textile, formed by means of a thermally activated adhesive that physically bonds the material webs or sheets. According to the invention, an impact pulse acts on the material webs or sheets arranged one above the other between a pair of unheated impact jaws, between which the adhesive is located. This represents a lifting movement of at least one of the impact jaws running perpendicular to the material webs or sheets, with at least one of the impact jaws penetrating the material webs or sheets for a duration of less than 10 ms, whereby the adhesive seam is formed. The adhesive seam is formed by the impact pulse penetrating the adhesive and deforming it.During deformation, heat develops in the adhesive, which is thermally activated, whereby the thermal activation is limited to the area of ​​the adhesive seam, in particular its horizontal extension.

[0011] The application of the impact pulse also results in a bonded seam height that is less than the height of both material webs or sheets that lie on top of each other and are joined by the bonded seam. The impact pulse also leads to deformation of the material webs or sheets.

[0012] During the production of the adhesive seam, all of the liquefied adhesive participates in the formation of the adhesive seam, and the area of ​​the liquefied adhesive remains limited to the adhesive seam. In contrast to heat sealing, the adhesive does not escape from the area of ​​the adhesive seam, thus preventing any adverse deformation along the adhesive seam. As a result, a higher-quality adhesive seam is achieved, and the adhesive can be used more efficiently by applying it in a narrower and thus smaller amount. The avoidance of squeezed-out adhesive, the limitation of the liquefied adhesive to the adhesive seam, and the compression of the seam are distinctive features of the adhesive seam produced according to the invention using an impact pulse.

[0013] It has been proven advantageous if the impact impulse penetrates at least 50% into the adhesive, i.e. at least 50% of the adhesive must be deformed.

[0014] The impact pulse is applied between the unheated impact jaws. In any case, heating the impact jaws is unnecessary; in fact, it is detrimental, especially if heating, or an external heat supply, leads to premature softening of the adhesive. Preheating the material webs or sheets is therefore also prohibited. Therefore, "unheated" refers to a temperature of the impact jaws and the material webs / sheets that is below the softening temperature of the adhesive. If, for other reasons, the impact jaws or the material webs / sheets are slightly heated, this does not affect the inventive method, and the impact jaws or the material webs / sheets are considered unheated or not preheated within the meaning of the invention.A pair of (unheated) jaws also exists if it is an unequal pair and one jaw works against a flat, non-profiled anvil, which then forms the second jaw of the pair within the meaning of the invention.

[0015] The impact pulse is a lifting movement of at least one of the impact jaws running essentially perpendicular to the material webs or material sheets, with a penetration time of at least one of the impact jaws into the material webs or material sheets with the adhesive in between of less than 10 ms. The penetration time is preferably less than 5 ms, particularly preferably less than 1 ms, and depending on the film thickness, 0.05 to 0.5 ms. For this purpose, the tool either crashes onto the build-up of material webs or material sheets with the adhesive, preferably at a speed of 1 to 5 m / s as the starting speed for the impact pulse, and is decelerated to a standstill during the penetration time, releasing and converting the kinetic energy. With the conversion of the kinetic energy of the impact pulse, the adhesive in particular is deformed and heats up in the process.The impact impulse is preferably caused by a mechanical drive, alternatively by an electric magnetic drive.

[0016] According to a first alternative, the thermally activated adhesive is applied to at least one of the material webs or sheets, at least in the area of ​​the bonded seam or even over the entire surface. Full-surface application offers greater flexibility in the location of the bonded seam, but also involves higher material consumption for the adhesive and more complicated recycling.

[0017] According to a second alternative, the thermally activated adhesive is placed between the material webs or sheets before the impact pulse is applied, at least in the area of ​​the adhesive seam to be created, without being connected to any of the material webs or sheets. In a web-running process, for example, a strip of adhesive could be fed from a roll between the material webs or sheets.

[0018] An advantageous embodiment or application involves joining the material web or sheet in the area of ​​the previously folded, opposite edges by the adhesive seam, which forms a longitudinal seam. This creates a tube. The stacked material webs or sheets can therefore also be a single folded material web or sheet.

[0019] According to a further embodiment, this tube is transformed into a tubular bag by at least one additional adhesive seam, which forms a transverse seam and closes 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, a top seam. A multi-layer tubular bag can also be produced in this way by adding a correspondingly larger number of layers during the formation of the tube.

[0020] It has been shown that the impact pulse creates an imprint in the material webs or sheets in the area of ​​the bonded seam, which is created when the impact jaws impact the material webs or sheets, following the contour of the impact jaws. This effect can be used for other applications, such as strengthening the material, imprinting information, or for aesthetic design.

[0021] Preferably, the thermally activated adhesive is a hot-melt adhesive, as is frequently used, not least in the packaging industry. Against this background, the advantageous application of the invention lies in material webs or sheets made of paper or a paper-based material. These materials also have a wide range of uses in the packaging industry and, in addition, rely on an adhesive bond when a material-to-material bond is required.

[0022] The object of the invention is further achieved by methods for joining material webs or material sheets using a thermally activated adhesive, wherein the material webs or material sheets are joined along an adhesive seam. According to the invention, an impact pulse, a lifting movement of at least one of the impact jaws running perpendicular to the material webs or material sheets, acts on the material webs or material sheets arranged one above the other between a pair of unheated impact jaws. Heating the impact jaws is not necessary; in fact, this would be disadvantageous, especially if heating, or an external heat supply, leads to softening of the material web / material sheet. Preheating of the material web / material sheet is therefore also prohibited. Therefore, "unheated" refers to a temperature of the impact jaws and the material web / material sheet that remains below the softening temperature of the material web / material sheet.If, for other reasons, the impact jaws or the material web / sheet are slightly heated, this does not affect the method according to the invention and the impact jaws or the material web / sheet are considered unheated or not preheated within the meaning of the invention.

[0023] Due to the rapid temperature rise, the material temperature has little influence, unless it leads to adverse softening of the material due to excessive temperature. The same applies to the impact jaws, which do not need to be preheated, as the temperature required for bonding is generated very quickly during the impulse in the material structure or in the adhesive itself. The heating and melting of the adhesive is therefore advantageously limited to an immediate effective zone and a short contact time. Due to the high deformation speed, adiabatic heating of the adhesive and also of the material web / sheet in the effective zone occurs with minimal energy input, without heat exchange with the surrounding air and the adjacent areas of the material web / sheet and the adhesive. Only as much adhesive is liquefied as is necessary for the bond.This also prevents liquid adhesive from being squeezed out of the joining area, the effective zone, and from participating in the joining connection to form the adhesive seam.

[0024] The adhesive seam is preferably very narrow, which not least leads to material savings. It also saves time and reduces energy input. Such a narrow adhesive seam or such a narrow heat-affected zone cannot be achieved with conventional heat-sealing processes for activating the adhesive because the heat would dissipate too quickly, thereby increasing the heated and softened area in the material web / sheet.

[0025] The impact pulse acts with a penetration time of at least one of the impact jaws into the material webs or sheets and the adhesive between them of less than 10 ms. It has proven advantageous if at least 50% of the adhesive is deformed during the impact pulse. This activates the adhesive and forms the bond line. This is followed by the immediate return stroke of at least one impact jaw to release the material web / sheet with the created bond line.

[0026] In a step preceding the impact pulse, the material webs or sheets and the adhesive are pressed against each other between the pair of impact jaws with a preload force Fv. The impact pulse from at least one of the driven impact jaws (or transmitted by at least one of the impact jaws) then acts on the material webs or sheets and the adhesive. Thus, as an alternative to the tool directly impacting the material web / sheet, the roughness of the tool surfaces, especially of the stacked material webs or sheets, is initially partially compensated with the adhesive. In all cases, a temperature effect arises in the effective zone, the resulting adhesive seam, which leads to a local melting of the adhesive, which is very brief during the penetration time and the mechanical stress occurring during penetration, at a correspondingly high deformation rate.

[0027] When transmitting the impact pulse, particularly through the impact jaws, the speed of sound and a shock pulse duration of less than 10 ms, preferably 5 ms, are assumed. For the steel-to-steel pulse, a duration of 0.25 ms was calculated for a distance of 10 cm. The impact pulse achieves an effect comparable to ultrasonic sealing on comparable materials; however, instead of a large number of low-amplitude pulses, only a single pulse is applied in ultrasonic sealing—the impact pulse according to the invention. In both processes, using ultrasound and an impact pulse, the temperature increase required for thermal joining is achieved through a physical-chemical effect in the adhesive.At the same time, further advantages are realized, in particular the lack of heat input and thus the thermal protection of the packaged goods, which are also crucial for the use of ultrasonic sealing, but without the need for complex system technology with ultrasound generation and sonotrode.

[0028] The melting of the adhesive remains limited to the effective zone. Consequently, the surrounding area is neither affected by unwanted heat input (e.g., the area surrounding the adhesive seam in a sheet of material or a packaged product), nor does heat flow into the environment as energy loss.

[0029] The impact pulse is preferably generated by a mechanical or magnetic drive, with the impact jaws being driven directly or the impact pulse being transmitted indirectly by spring force, a drop weight, a magnetic drive, or a cam-driven mechanism. The cam-driven mechanism allows particularly fast movements to be controlled without delay and with precise amplitude. In particular, the spring force and the drop weight can be manually adjusted to the position where they generate force, allowing the method according to the invention to be carried out without an external power supply.

[0030] The impact pulse is applied by the upper impact jaw or, alternatively, by both impact jaws acting against each other. Especially with opposing impact jaws, these can also be used for and integrated into a high-speed process, for example, in a flow-wrapping machine, e.g., with 100 cycles per minute. The impact jaws can be designed as rollers that also function as feed rollers, for example. The feed rollers apply the preload force F vwhile the impulse force F is transferred by an impact on the rollers to the material web / material sheet or the adhesive arranged therebetween. According to a first alternative, the thermally activatable adhesive is applied to at least one of the material webs or material sheets at least in the area of ​​the adhesive seam and is then bonded to the material web / material sheet. According to a second alternative, the thermally activatable adhesive is arranged between the material webs or material sheets at least in the area of ​​the adhesive seam to be produced before the impact impulse is applied, without being bonded to either of the material webs or material sheets.

[0031] Furthermore, it has proven advantageous to join the material web or sheet at the edges with the adhesive seam, which forms a longitudinal seam, to form a tube. Furthermore, the tube can be sealed with adhesive seams that form transverse seams, creating a tubular bag.

[0032] According to an advantageous embodiment, a strip of the thermally activatable adhesive is fed at the same time as the material web or the material sheet when the tube is formed from the material web or the material sheet and is introduced between the overlapping edges of the material web or the material sheet or is arranged therebetween.

[0033] It has been shown that the impact of the impact jaws on the material webs or sheets creates an imprint in the material webs or sheets corresponding to the contour of the impact jaws. It has also proven advantageous to use the opposing impact jaws in a continuous, high-speed process, as already explained in more detail above.

[0034] The thermally activated adhesive is preferably a hot-melt adhesive. The material webs or sheets are preferably made of paper or a paper material that requires an adhesive for bonding and, unlike plastic film, cannot be welded.

[0035] Another advantageous alternative is an adhesive seam, which is designed as a single adhesive point and connects the material web sheets by means of a large number of such adhesive points arranged in a row. This allows any seam shape, each consisting of a large number of adhesive points, to be produced without the need for specially shaped impact jaws. Furthermore, a low pulse energy is sufficient for the small area of ​​the adhesive points, allowing the system to be compact and implemented without complex drives. To achieve broad flexibility, this process is suitable for material web sheets completely coated with adhesive.

[0036] The object of the invention is further achieved by a device for joining material webs or sheets along an adhesive seam using a thermally activatable adhesive. According to the invention, the device comprises a pair of unheated impact jaws. A pair of unheated impact jaws also exists when one impact jaw works against an abutment, a flat anvil, which then forms the second impact jaw of the pair. The pair of unheated impact jaws is intended for the introduction of the material webs or sheets arranged one above the other with the adhesive arranged between them. Furthermore, a device for pulse generation is included, which is designed to introduce an impact pulse into at least one of the impact jaws to activate the adhesive.The impact pulse represents a reciprocating movement of at least one of the impact jaws perpendicular to the material webs or sheets, with a penetration time of less than 10 ms into the material webs or sheets and into the adhesive. The impact pulse acts on the material webs or sheets and, by activating the adhesive, forms the adhesive seam in the effective area of ​​the impact jaws. The impact pulse is preferably generated by a drive device.

[0037] According to an advantageous further development, a device for applying a pre-tensioning force (F v ) are provided, by which the impact jaws are clamped by means of the pre-tensioning force (F v ) are pressed against each other.

[0038] In the preferred embodiment, the pair of impact jaws consists of at least a first impact jaw with an effective area having a profiled cross-section. It has further proven advantageous if the pair of impact jaws includes the second impact jaw with a flat effective area. An advantageous profiled cross-section has a flat profile delimited by two radii R2 with any desired contour shape and a width a that covers at least the area of ​​the adhesive seam. According to a preferred embodiment, the profiled cross-section is designed at the effective point, which is in contact with the material webs to be bonded during the bonding process or the impact pulse, as a flat profile delimited on both sides by two radii R2, preferably with R2 = 1 to 4 mm, with a width a, at least a = 2 mm.

[0039] According to an advantageous embodiment, the first and / or the second impact jaw are designed as a rolling tool for action in a web-running process with continuous feed, previously also explained in more detail as a high-speed process. Alternatively, the first and / or the second impact jaw are designed as a tool that pivots towards the point of action or as a tool that is temporarily carried along with the web during the gluing process, as is customary and generally known for certain processing stages in web-running processes. The device according to the invention is therefore suitable for installation in packaging systems, whereby established sealing technology can also be replaced. It has proven advantageous if the pair of impact jaws is made of hardened steel with a ground surface. Furthermore, each of the impact jaws contains elements for attachment to the drive device.

[0040] According to a first embodiment, the drive device acts on the first impact jaw, or according to a second embodiment, on the first and second impact jaws. The drive device 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-disk drive, the advantages of which have already been explained above. Furthermore, a magnetic drive is provided, which directly drives the impact jaw or an associated plunger.

[0041] A further aspect of the present invention relates to the use of an impact press as a drive device for a device for joining material webs or sheets of material by means of a thermally activatable adhesive, as described above.

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

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

[0044] • cold tools, adiabatic joining process,

[0045] • Can be used with heat-sensitive products,

[0046] • very cost-effective and robust plant and tool technology,

[0047] • purely mechanical and manually operated solutions can be implemented (spring preload),

[0048] • extremely short processing time,

[0049] • smallest seam widths possible,

[0050] • Specific seam or embossing patterns can be achieved through profile patterns of the tools,

[0051] • Common packaging forms (sealed edge bags, tubular bags) can be implemented,

[0052] • very low energy consumption, therefore very high energy efficiency.

[0053] By comparison, thermal pulse joining of a material web / sheet 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. This corresponds to an energy consumption of 200 J for a sealing tool. In contrast, joining using the method according to the invention requires only 5 J of energy for the same seam length. This corresponds to an energy saving of 97.5%.

[0054] The advantages mentioned above result in advantageous applications in the following areas: • Packaging process with material web sheets (technical products, food, medical products) both for fast-running series applications and for individual processes in decentralized production,

[0055] • Use for continuous processes due to high process speed,

[0056] • Use with recyclable and compostable films,

[0057] • Applications for sealing without electrical energy using spring preload for mobile use, medical technology for development aid (packaging medical samples on site), disaster relief (sealing sandbags),

[0058] • Packaging in dusty environments.

[0059] The invention is explained in more detail below based on the description of exemplary embodiments and their illustration in the accompanying drawings. They show:

[0060] Fig. 1: schematically a view of a process sequence of the method according to the invention for joining material web sheets by thermal joining;

[0061] Fig. 2: schematically a perspective view of an embodiment of an impact jaw according to the invention with an effective area with a flat profiled cross-section, limited by two radii;

[0062] Fig. 3: schematically a perspective view of an embodiment of a first impact jaw according to the invention with an effective area with a flat profiled cross-section;

[0063] Fig. 4: schematically a perspective view of an embodiment of a second impact jaw according to the invention with a flat effective area;

[0064] Fig. 5: schematically in two views an embodiment of an impact press;

[0065] Fig. 6: schematic side view of an embodiment of a continuous web running process;

[0066] Fig. 7: schematically in two views a further embodiment of a continuous web running process;

[0067] Fig. 8: schematically a perspective view of an embodiment of an adhesive seam according to the invention on a hose;

[0068] Fig. 9: schematically a perspective view of an embodiment of adhesive seams according to the invention on a tubular bag;

[0069] Fig. 10: schematically shows a side view of an embodiment of a device according to the invention with a joined material web bend and Fig. 11: schematically shows an enlarged view of a joining point with joined material web bends.

[0070] Fig. 1 shows a schematic view of an embodiment of a process sequence of the inventive method for joining material webs 10 by means of a thermally activated adhesive 11 using an impact pulse. The process sequence is shown in three steps, starting from the left. First, a first impact jaw 2 is moved along the feed path s zThe material sheet 10 is moved in the direction of the arrow up to the surface of the material sheet 10, between which the adhesive to be activated, a hot melt adhesive 11, is arranged, until an active profile 6 touches the material sheet 10. The two material sheet 10, which are to be joined by an adhesive seam 12, rest on the surface of the second impact jaw 4, here designed as a flat anvil. The active profile 6 is also flat and tapers in radii to avoid damaging the material sheet 10.

[0071] In a second step, the first impact jaw 2 is subjected to a pre-tensioning force F vpressed against the material web sheets 10 with the hot-melt adhesive 11 located between them. Under the preload thus created, which compensates for roughness and the elasticity of the material structure, the impulse force F is applied in the third step, which activates the hot-melt adhesive 11, which melts briefly in the active zone, and thus forms the adhesive seam 12.

[0072] Fig. 2 schematically shows a perspective view of an embodiment of an impact jaw 2 according to the invention with a flat profiled cross-section which runs into two radii R2 and forms an effective profile 6, as used in Fig. 1. In an exemplary effective profile 6, the preferred radius R2 = 1 to 4 mm and the flat profile has at least a width of a = 2 mm.

[0073] Fig. 3 shows a schematic perspective view of an embodiment of a first impact jaw 2 according to the invention with an effective area 6 with a flat profiled cross-section, as shown in detail in Fig. 2. A receiving opening 8 serves for the insertion of a clamping bolt (not shown here), with which the first impact jaw 2 is fastened in an impact jaw receptacle 26 (see Fig. 5) of a machine which applies the preload force F v and applies the impulse force Fj to the first impact jaw 2. Fig. 4 schematically shows a perspective view of an embodiment of a second impact jaw 4 according to the invention with a flat, anvil-like effective area 6. The second impact jaw 4 is fastened to an impact jaw holder 28 (see Fig. 5).

[0074] Fig. 5 schematically shows two views of 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 energy and purely manually, in particular as a spring impact press according to the illustrated embodiment. The force required for the feed movement over the feed path s z as well as for the preload force F v and the impulse force Fj are applied by the operator via an operating lever 24.

[0075] As shown in Fig. 1, the adhesive seam 12 is created between the second impact jaw 4, on which the material web sheets 10 rest, and the first impact jaw 2, which is fastened in a first impact jaw receptacle 26. For this purpose, the operating lever 24 is moved, and a feed device 32 moves the first impact jaw receptacle 26 toward the second impact jaw receptacle 28 until the first impact jaw 2 inserted in the first impact jaw receptacle 26 touches the material web / material sheet 10.

[0076] By further movement of the operating lever 24, the required preload force F vand after further movement of the operating lever 24, which tensions a spring, the impulse force Fj is applied to the material web or sheet 10 by triggering the impulse generator 30. The adhesive seam 12 is thus created in the area of ​​a contact zone between the first impact jaw 2 and the second impact jaw 4. The return stroke of the second impact jaw holder 26 by countermovement of the operating lever 24 leads to the release of the sealed, bonded material webs or sheets 10.

[0077] Fig. 6 shows a schematic side view of an embodiment of a continuous web travel process in which the material web / material sheet 10 runs off a web roll 40. In the device 1 for joining material web sheets 10 by gluing, the material web sheets 10 run between the first impact jaw 2 and the second impact jaw 4, where the adhesive seam 12 is created (in the illustration, the adhesive seam 12 is not yet formed). However, precautions must be taken to ensure the continuity of the web travel process even during the action of the pretensioning force in particular, but also the impact impulse. This can be achieved, for example, by cyclically moving and returning the device 1 in or against the web travel direction or by a web storage device upstream of the device 1 (both not shown, but known from the prior art).

[0078] Fig. 7 shows a schematic side view of another embodiment of a continuous web-running process. The pre-tensioning force is applied by pre-tensioning rollers 42, between which the material web(s) 10 pass. A pulse-generating device 30, in particular an impact gear, acts on one or both pre-tensioning rollers 42, thereby creating the adhesive seam 12.

[0079] Fig. 8 schematically shows a perspective view of an embodiment of an adhesive seam 12 according to the invention on a tube 14 formed from a folded and joined section of a material web 10. The tube 14 can advantageously be used as a sleeve packaging, being pushed over an otherwise finished packaging.

[0080] Fig. 9 schematically shows a perspective view of an embodiment of further adhesive seams 12 according to the invention, here on a tubular bag 16. This comprises a tube 14, as shown in Fig. 8, which is closed at both ends with transverse seams. This is usually done on the second, usually upper side after filling with a packaged product. A bottom seam, the lower adhesive seam 12, of the next tubular bag 16 can be created at the same time.

[0081] Fig. 10 schematically shows a side view of an embodiment of a device 1 according to the invention during bonding of the material web sheets 10, forming an adhesive seam 12. This is particularly clear in the enlarged view in Fig. 11. The device 1 comprises the impact jaws 2, 4, shown after the return stroke, which releases the adhesive seam 12.

[0082] Fig. 11 schematically shows an enlarged view of a bonded joint, the adhesive seam 12 with connected material sheet bends 10, with the material sheet bends 10 extending on both sides of the adhesive seam 12. The very low adhesive seam 12 in the effective zone, the hot-melt adhesive 11 fused to the material sheet bends 10, is visible. The compression is partly due to the fact that the material sheet bends 10 are made of a compressible or heat-sensitive material, the height of which was also reduced by the impact impulse.

[0083] The hot-melt adhesive 11, which protrudes undeformed next to the adhesive seam 12, does not appear thickened, as is the case with other prior art heat-sealing processes due to the extrusion of liquid adhesive. This clearly shows that no excess adhesive 11 is melted and displaced. Rather, the heat-affected zone 13, whose boundary to the unaffected material web, is

[0084] 10 (and the hot-melt adhesive 11, insofar as it projects beyond the activation zone in the area of ​​the adhesive seam) is represented by a dashed line, is limited to the area of ​​the adhesive seam 12 and neither the material webs 10 nor an area outside the material webs 10, for example a packaged item within a package, are affected by undesired heating.

[0085] List of reference symbols

[0086] 1 device

[0087] 2 first jaw

[0088] 4 second jaw

[0089] 6 Effective range, effective profile

[0090] 8 Receiving opening

[0091] 10 Material track sheets

[0092] 11 Adhesive, thermally activated; hot melt adhesive

[0093] 12 Glued seam, longitudinal seam, transverse seam

[0094] 13 Heat-affected zone

[0095] 14 hose

[0096] 16 tube bags

[0097] 20 impact press

[0098] 22 stands

[0099] 24 control levers

[0100] 26 first impact jaw holder

[0101] 28 second impact jaw holder

[0102] 30 (Device for) pulse generation

[0103] 32 Feed device

[0104] 40 web rolls

[0105] 42 Rolling tool, pre-tension roller a effective profile width

[0106] R1 first effective profile radius

[0107] R2 second effective profile radius

[0108] R3 third effective profile radius

[0109] F v Preload force

[0110] Fi Impulse force, intensity of the impact impulse s Delivery path

Claims

Patent claims 1. Adhesive seam for joining material webs or material sheets (10) by means of a thermally activatable adhesive (11), characterized in that an impact pulse, a lifting movement of at least one of the impact jaws (2, 4) running perpendicular to the material webs or material sheets (10) with a penetration time of at least one of the impact jaws (2, 4) into the material webs or material sheets (10) of less than 10 ms, is applied to the material webs or material sheets (10) arranged one above the other between a pair of unheated impact jaws (2, 4), between which the adhesive (11) is located, wherein the impact pulse forms the adhesive seam (12) by the impact pulse penetrating at least partially into the adhesive (11) and thereby thermally activating the adhesive, wherein the thermal activation is limited to the area of ​​extension of the adhesive seam (12), and wherein a height of the adhesive seam (12) results,which is less than the height of both material webs or material sheets (10), and wherein all 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. Adhesive seam according to claim 1, wherein the thermally activatable adhesive (11) is applied to at least one of the material webs or material sheets (10) at least in the region of the adhesive seam (12).

3. Adhesive seam according to claim 1 or 2, wherein the thermally activatable adhesive (11) is arranged between the material webs or material sheets (10) at least in the region of the adhesive seam (12) to be produced without connection to the material webs or material sheets (10) before the impact pulse is applied.

4. Adhesive seam according to one of the preceding claims, wherein the material web or the material sheet (10) is connected in the region of the edges by the adhesive seam (12), which forms a longitudinal seam, and a tube (14) is formed.

5. Adhesive seam according to one of the preceding claims, wherein the tube (14) is closed by the adhesive seams (12) which form transverse seams and produce a tubular bag (16).

6. Adhesive seam according to one of the preceding claims, wherein the thermally activatable adhesive (11) is a hot-melt adhesive.

7. Adhesive seam according to one of the preceding claims, wherein the material webs or material sheets (10) consist of paper or a paper material.

8. Method for joining material webs or material sheets (10) by means of a thermally activatable adhesive (11), wherein the material webs or material sheets (10) are connected along an adhesive seam (12), characterized in that an impact pulse acts on the material webs or material sheets (10) arranged one above the other between a pair of unheated impact jaws (2, 4), a lifting movement of at least one of the impact jaws (2, 4) running perpendicular to the material webs or material sheets (10) with a penetration time of at least one of the impact jaws (2, 4) into the material webs or material sheets (10) and the adhesive (11) shorter than 10 ms, by which the adhesive (11) is activated and the adhesive seam (12) is formed, followed by the return stroke of the at least one impact jaw (2, 4).

9. Method according to claim 8, wherein in a step preceding the impact pulse, the material webs or material sheets (10) and the adhesive (11) are clamped between the pair of impact jaws (2, 4) with a prestressing force F vare pressed against each other and then the impact pulse of at least one of the driven impact jaws (2, 4) or passed on by at least one of the impact jaws (2, 4) acts on the material webs or material sheets (10) and the adhesive (11).

10. Method according to claim 8 or 9, wherein the mechanical drive of the impact jaws (2, 4) is effected directly or the indirectly transmitted impact pulse is effected by spring force, a drop weight, a magnetic drive or a cam disk drive.

11. Method according to one of claims 8 to 10, wherein the impact pulse is applied by the upper impact jaw (2) or by both impact jaws (2, 4) acting against each other.

12. Method according to one of claims 8 to 11, wherein the thermally activatable adhesive (11) is arranged between the material webs or material sheets (10) at least in the region of the adhesive seam (12) to be produced before the impact pulse is applied.

13. Method according to one of claims 8 to 12, wherein the adhesive seam according to claim 1, wherein the thermally activatable adhesive (11) is applied between at least one of the material webs or material sheets (10) at least in the region of the adhesive seam (12).

14. Method according to one of claims 8 to 13, wherein the material web or the material sheet (10) is connected in the region of the edges by the adhesive seam (12), which forms a longitudinal seam, and a tube (14) is formed.

15. The method according to claim 14, wherein a strip of adhesive (11) is supplied at the same time as the material web or sheet during the formation of the tube (14) from the material web or sheet and is arranged between the overlapping edges of the material web or sheet.

16. Method according to one of claims 8 to 15, wherein the tube (14) is closed by the adhesive seams (12) which form transverse seams and produces a tubular bag (16).

17. The method according to claim 16, wherein the opposing impact jaws (2, 4) are used in a continuous, high-speed process.

18. Method according to one of claims 8 to 17, wherein the thermally activatable adhesive (11) is a hot melt adhesive.

19. Method according to one of claims 8 to 18, wherein the material webs or material sheets consist of paper or a paper material.

20. A device for joining material webs or sheets (10) by means of a thermally activatable adhesive (11) along an adhesive seam (12), characterized in that the device (1) comprises a pair of unheated impact jaws (2, 4), designed to introduce the superimposed material webs or sheets (10) with the adhesive (11) therebetween, wherein a pulse generating device (30) is included, which applies the impact pulse to at least one of the impact jaws (2, 4) to activate the adhesive (11), wherein the impact pulse represents a lifting movement of at least one of the impact jaws (2, 4) running perpendicular to the film layer with a penetration time of at least one of the impact jaws (2, 4) into the material webs or sheets (10) and the adhesive (11) of less than 10 ms,wherein the impact pulse acts on the material webs or material sheets (10) and, by activating the adhesive (11), forms the adhesive seam (12) in an effective area of ​​the impact jaws (2, 4).

21. Device according to claim 20, wherein a device for applying a prestressing force (F v ) the impact jaws (2, 4) before applying the impact impulse by means of the pre-tensioning force (F v ) are pressed against each other.

22. Device according to claim 20 or 21, wherein a profiled cross-section (6) is designed as a flat profile delimited by two radii R2 with a width a which covers at least the area of ​​the adhesive seam (12).

23. Device according to one of claims 20 to 22, wherein the first and / or the second impact jaw (2, 4) are designed to act in a web running process with continuous feed.

24. Device according to claim 23, wherein the first and / or the second impact jaw (2, 4) is designed as a rolling tool (42), as a tool pivoting towards the effective point or as a tool carried along with the web during the bonding process.

25. Device according to one of claims 20 to 24, wherein the means for generating the pulse (30) comprises a spring, a drop weight or a mechanical gear.

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

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