Adhesive seam, method and device for joining webs or sheets of material with a heat-activated adhesive and using an impact press

Abstract

The present invention relates to a bonded seam, method, and device for joining material webs (10) using a heat-activated adhesive, specifically a hot-melt adhesive (11), where the material webs (10) are joined along a bonded seam (12) between impact elements (2, 4). According to the present invention, an impact pulse is applied to material webs or sheets (10) positioned one above the other between a pair of unheated impact elements (2, 4), with the adhesive (11) positioned between the material webs or sheets (10). The bonded seam (12) is formed by the impact pulse, which at least partially penetrates the adhesive (11) and thus activates it, with the activation being limited to the area of ​​the extension of the bonded seam (12), resulting in a bonded seam (12) height that is smaller than the height of both material webs or sheets (10), with all of the liquefied adhesive (11) participating in the formation of the bonded seam (12), and the area of ​​the liquefied adhesive (11) remaining limited to the bonded seam (12). The present invention also relates to a method for using an impact press.

Description

[Technical Field]

[0001] The present invention relates to a bonding seam for joining webs or sheets of material using a heat-activated adhesive, in particular a hot melt adhesive. The webs or sheets of material are in particular made of non-sealing materials such as paper, metal, or textiles. Formed webs or sheets of material, or sections thereof, are also included within the scope of the present invention, including sections of webs or sheets of material that have already been formed into packaging containers. The present invention also relates to a method or device for joining webs or sheets of material using a heat-activated adhesive, where the webs or sheets of material are joined along a bonding seam, and the present invention also relates to the use of an impact press. [Background technology]

[0002] One important application area for integral bonding using heat-activated adhesives is the manufacture and sealing of packaging. Hot melt adhesives (also called hot melt adhesives, hot melts, thermal adhesives, or hot melt adhesives) enable fast sealing, for example, within boxes, as outer or assembly packaging. The adhesive melts upon application of heat, thereby activating the adhesive for integral bonding. After being applied to the bonding area, the adhesive cools and hardens within a short time. Once the adhesive hardens, the adhesive joint can be immediately installed. A disadvantage is that sprayed hot melt adhesives are very difficult to remove during equipment cleaning. Furthermore, hot melt adhesives require sufficient contact pressure after application to obtain a strong adhesive joint, so they can only be used on relatively large, stable objects. Directly applied hot melt adhesives are particularly unsuitable for flexible materials and very small bonding areas.

[0003] To avoid the disadvantages associated with applying hot melt adhesive at the time of bonding, the hot melt adhesive may already be applied over the entire surface in advance or exclusively in the subsequent bonding area. Such solutions are known in various embodiments, for example in the published document DE 102019112788 A1. A device and method for coating a material web or sheet, specifically a paper web or sheet, with hot melt adhesive is described. In this case, the hot melt adhesive is applied in stripes only where bonding will occur later. The material web or sheet thus treated is then suitable for processing and bonding in a known heat sealing process. For this purpose, the coated material web is bonded to another layer of material in a sealing zone, where the required amount of heat is introduced into the material.

[0004] Heat sealing refers to thermal joining using heated welding elements (also known as sealing elements). Methods and devices for heat sealing are described in the published documents DE 102011080462 A1 and DE 102016218190 A1. Many efforts are made without using heated welding elements. There are two main reasons for this: safe packaging of heat-sensitive goods while avoiding the input of thermal energy, and reducing energy consumption.

[0005] Thermal bonding using ultrasound can eliminate the need for heated impact elements, since 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 the ultrasonic sealing solutions described in combination with heat sealing in the published documents DE 69926758 A1, DE 102009046319 A1, and DE 102017121572 A1. However, the mechanical equipment required for ultrasonic sealing and ultrasonic generation is very complex.

[0006] Alternatively, heat input can be avoided by using low-temperature sealable polymer dispersions, as proposed in published document WO 2011 / 003864, however this requires the application of special polymer dispersions at the joints.

[0007] Other methods for treating material webs or sheets, such as separating material webs or sheets using impact pulses using a foil punch according to published document DE 10 2015 211 622 A1, are also not suitable for joining material webs or sheets coated with hot melt adhesive together to form adhesive or hermetic seams. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] German Patent Application Publication No. 102019112788 [Patent Document 2] German Patent Application Publication No. 102011080462 [Patent Document 3] German Patent Application Publication No. 102016218190 [Patent Document 4] DE 69926758 [Patent Document 5] German Patent Application Publication No. 102009046319 [Patent Document 6] German Patent Application Publication No. 102017121572 [Patent Document 7] International Publication No. 2011 / 003864 [Patent Document 8] German Patent Application Publication No. 102015211622 Summary of the Invention [Problem to be solved by the invention]

[0009] It is therefore an object of the present invention to provide a bonded seam for joining material webs or sheets made, for example, of paper but also of metal or textiles, using a heat-activated adhesive, and also to provide a robust and simple method for joining material webs or sheets along a bonded seam with a heat-activated adhesive.A further object of the present invention is to provide an energy-saving, simple device for joining material webs or sheets along a bonded seam with a heat-activated adhesive, and also the use of an impact press. [Means for solving the problem]

[0010] This problem is solved by a bonded seam for joining material webs or sheets, for example, made of paper or paper materials, but also metal or textiles, formed using a heat-activated adhesive that substantially bonds the material webs or sheets. According to the invention, an impact pulse is applied to the material webs or sheets arranged one above the other between a pair of unheated impact elements, with the adhesive positioned between the material webs or sheets. This represents at least one stroke movement of the impact elements perpendicular to the material web or sheet, with a penetration period of less than 10 ms during which at least one of the impact elements penetrates the material web or sheet, thereby forming a bonded seam. The bonded seam is formed by the impact pulse by penetrating the adhesive and deforming it. During the deformation, heat is generated in the adhesive, which heat-activates the adhesive, and the heat activation is limited to the area of ​​the bonded seam, specifically its horizontal extent.

[0011] The application of the impact pulse also causes the height of the adhesive seam to be smaller than the height of both of the material webs or sheets that are located above and below and that are joined together by the adhesive seam, and the impact pulse also causes a deformation of the material web or sheet.

[0012] During the formation of the bonded seam, all of the liquefied adhesive is involved in the formation of the bonded seam, and the area of ​​liquefied adhesive remains limited to the bonded seam. Therefore, in contrast to heat sealing, the adhesive does not escape from the area of ​​the bonded seam, and as a result, no adverse deformation occurs along the bonded seam. This results in a high-quality bonded seam and a more efficient use of adhesive, as the adhesive can be applied thinner and therefore in smaller amounts. The avoidance of adhesive extrusion or the limitation of liquefied adhesive to the bonded seam, as well as the compression of the seam, are characteristics of the bonded seam created by the shock pulse according to the present invention.

[0013] It has proven advantageous for the shock pulse to penetrate into at least 50% of the adhesive, ie it must deform at least 50% of the adhesive.

[0014] The impact pulse occurs between unheated impact elements. In any case, it is not necessary to heat the impact elements. Indeed, such heating would be disadvantageous, especially if an external supply of heat would result in premature softening of the adhesive. Therefore, preheating of the material web or sheet is also excluded. "Unheated" is therefore understood as a state in which the temperature of the material web or sheet remains below the softening temperature of the adhesive. For other reasons, the impact elements or the material web / sheet may be slightly heated, which does not affect the method according to the present invention, and the impact elements and the material web / sheet are considered unheated or unpreheated within the meaning of the present invention. Furthermore, if the impact elements are in an uneven pair and one impact element acts against a flat, unformed anvil, a pair of (unheated) impact elements exists, which then constitutes the second impact element in the pair within the meaning of the present invention.

[0015] The impact pulse is a stroke of at least one impact element substantially perpendicular to the material web or sheet, with a penetration period of less than 10 ms during which at least one impact element penetrates the material web or sheet while adhesive is present between the materials. Preferably, the penetration period is less than 5 ms, particularly less than 1 ms, and is 0.05-0.5 ms depending on the film thickness. For this purpose, the tool penetrates the adhesive-attached material web or sheet assembly, preferably with a starting speed of 1-5 m / s relative to the impact pulse, and decelerates to a stop during the penetration period, simultaneously releasing and converting its kinetic energy. The conversion of the kinetic energy of the impact pulse particularly deforms and thereby heats the adhesive. The impact pulse is preferably generated by a mechanical drive, or alternatively by an electro-magnetic drive.

[0016] According to a first alternative, the heat-activated adhesive is applied to at least one of the material webs or sheets at least in the area of ​​the glued seam or over the entire surface. Full surface application is associated with high conformability at the location of the glued seam, but also with a high adhesive material consumption and a complex recycling process.

[0017] According to a second alternative, the heat-activated adhesive is placed between the material webs or sheets, at least in the area of ​​the bonded seam to be created, before the impact pulse is applied, and is not bonded to one of the material webs or sheets. In a web-guiding process, for example, a strip of adhesive from a roll can be fed between the material webs or sheets.

[0018] An advantageous embodiment or application comprises that the material webs or sheets are joined in the area of ​​the previously opposite edges folded relative to one another by adhesive seams, thereby forming a longitudinal seam, thus forming a tube. The material webs or sheets arranged one above the other can therefore also be a single material web or sheet in a folded state.

[0019] According to a further embodiment, the tube is made into a tube bag with at least one additional glued seam, which forms a transverse seam and seals the preformed tube at at least one end with a bottom seam. To close the tube bag, the opening is also provided with a transverse seam, i.e., a top seam. In this way, by adding more layers when the tube is formed, multi-layer tube bags can also be produced.

[0020] It has been shown that the impact pulse causes embossing of the material web or sheet in the area of ​​the adhesive seam, which is formed by the impact of the impact element against the material web or sheet according to the contour of the impact element, and this effect can be used for further applications, such as to strengthen the material, to emboss information or for aesthetic design.

[0021] Preferably, the heat-activated adhesive is a hot melt adhesive, which is frequently used, in particular in the packaging industry. In this context, an advantageous application of the present invention is with material webs or sheets made of paper or paper materials, which are also widely used in the packaging industry and which, moreover, rely on adhesive bonding when integral bonding is required.

[0022] The object of the present invention is further achieved by a method for bonding material webs or sheets using a heat-activated adhesive, in which the material webs or sheets are bonded along a glue seam. According to the present invention, an impact pulse acts on a material web or sheet arranged one above the other between a pair of unheated impact elements, with at least one stroke movement of the impact elements extending perpendicular to the material web or sheet. Heating of the impact elements is not required. In fact, such heating would be disadvantageous, especially if an external supply of heat were to result in softening of the material web or sheet. Therefore, preheating of the material web or sheet is also excluded. Therefore, "unheated" is understood as a state in which the temperatures of the impact element and the material web or sheet remain below the softening temperature of the material web or sheet. For other reasons, the impact element or the material web / sheet may be slightly heated, which does not affect the method according to the present invention. Therefore, the impact element or the material web / sheet is not considered to be heated or preheated within the meaning of the present invention.

[0023] The rapid temperature rise has little effect on the material temperature, unless excessive temperatures adversely soften the material. Similarly, it applies to impact elements that do not require preheating. This is because the temperature required for welding is generated very quickly during the pulse, either within the material web or sheet or within the plastic film itself. Therefore, heating and melting of the adhesive are advantageously limited to the nearby effective zone and short contact time. Due to the fast deformation speed, adiabatic heating of the adhesive and / or the material web or sheet within the effective zone occurs with minimal energy input, and no heat exchange occurs between the surrounding air and adjacent areas of the material web or sheet and adhesive. The adhesive is liquefied only to the extent necessary for bonding. At the same time, this prevents the liquid adhesive from escaping from the bond area or effective zone and entering the joint to form a bonded seam.

[0024] The adhesive seam is preferably produced to be very narrow, which, among other things, results in savings in material, as well as time and reduced energy input. Such narrow adhesive seams or such narrow heat-affected zones cannot be achieved by conventional heat-sealing processes for activating adhesives, because the heat dissipates rather quickly, thereby expanding the heated and softened area within the material web or sheet.

[0025] The penetration period during which at least one of the impact elements penetrates the material web or sheet with the adhesive between them is less than 10 ms, and the impact pulse then acts. It is advantageous if at least 50% of the adhesive is deformed during the impact pulse, thereby activating the adhesive and forming a bonded seam. This is followed by a quick return stroke of at least one impact element to release the applied material web or sheet with the formed bonded seam.

[0026] In the step preceding the impact pulse, the material web or sheet and adhesive are subjected to a pretension force F v The material web or sheet is pressed against each other between a pair of impact elements at a constant speed. At least one impact pulse of the actuated impact element (or transmitted by at least one of the impact elements) then acts on the material web or sheet and the adhesive. Thus, as an alternative to a tool falling directly onto the material web or sheet, the roughness of the tool surface, in particular the roughness of the material webs or sheets arranged above and below, is initially partially compensated by the adhesive. In all cases, temperature effects occur in the impact zone, i.e., at the developing adhesive seam, which leads to a very short local melting of the adhesive during the penetration period, and mechanical loads are generated during penetration, resulting in a correspondingly faster deformation speed.

[0027] Specifically, the sound velocity and duration of the shock pulse transmitted by the impact element are assumed to be less than 10 ms, preferably 5 ms. For a steel-to-steel pulse, the duration of 0.25 ms is calculated for a distance of 10 cm. Using shock pulses, an effect equivalent to ultrasonic sealing is achieved with comparable materials. However, instead of multiple pulses of low amplitude as in ultrasonic sealing, only a single pulse, i.e., the shock pulse according to the present invention, is applied. In both processes, when using ultrasound and shock pulses, the temperature increase required for thermal bonding is achieved by the physicochemical effects of the adhesive. At the same time, further advantages are realized, specifically, no heat input and thus thermal protection of the packaged product, and the need for complex equipment involving an ultrasonic generator and sonotrode, which is a crucial factor in the use of ultrasonic sealing, is eliminated.

[0028] The melting of the adhesive remains limited to the effective zone, and as a result, the environment (e.g., the area surrounding the adhesive seam of the material web or sheet, or packaged product) is not subjected to unwanted heat input, and heat is not dissipated to the surroundings as energy loss.

[0029] The impact pulse is preferably generated by a mechanical or magnetic drive, and the mechanical drive of the impact element is directly driven, or the impact pulse is transmitted indirectly using a spring force, a falling weight, a magnetic drive, or a cam gear. The use of a cam gear allows particularly fast movements to be controlled without delay and with precise amplitude. In particular, the spring force and the falling weight can be manually shifted to the position where the force is generated. As a result, the method according to the invention can be carried out without an external energy supply.

[0030] The impact pulses are applied by the upper impact element or, alternatively, by both opposing impact elements. In particular, by using opposing impact elements, these can also be used for high-speed processes, for example at 100 cycles / min, and integrated into, for example, tube bag machines. In this connection, the impact elements can be configured as rollers that can simultaneously function as feed rollers. The feed rollers are applied with a pretension force F v While applying a pulse force F i is transferred by the impact of the roller to the web or sheet of material and the adhesive disposed therebetween.

[0031] According to a first alternative, the heat-activated adhesive is applied to at least one of the material webs or sheets, at least in the area of ​​the bonded seam, and then the heat-activated adhesive is bonded to the material webs or sheets. According to a second alternative, the heat-activated adhesive is placed between the material webs or sheets, at least in the area of ​​the bonded seam to be created, before the impact pulse is applied, and the heat-activated adhesive is not bonded to either of the two material webs or sheets.

[0032] Furthermore, the material webs or sheets are joined in the edge area by adhesive seams, which form longitudinal seams to produce a tube, and further adhesive seams forming cross seams which allow the tube to be closed, thereby producing a tube bag.

[0033] According to an advantageous embodiment, strips of heat-activated adhesive are supplied together with the material web or sheet and are introduced or placed between the overlapping edges of the material web or sheet during the formation of the tube.

[0034] It has been shown that when the impact element strikes the material web or sheet, an embossment is produced in the material web or sheet that corresponds to the contour of the impact element. As explained in more detail above, opposing impact elements are used in a continuous, high speed process.

[0035] Preferably, the heat activated adhesive is a hot melt adhesive. Preferably, the material web or sheet is made from paper or paper material, which requires an adhesive to bond the material and, unlike plastic films, cannot be welded.

[0036] A further advantageous alternative is an adhesive seam designed as adhesive points, whereby the material web or material sheet is joined by a plurality of adhesive points arranged in a row. In this way, any seam shape can be generated, each consisting of a plurality of adhesive points, without the need for shaping impact elements, depending on the situation. Furthermore, only low pulse energy is required for the small area of ​​the adhesive points, resulting in a compact system that can be implemented without complex drive mechanisms. To achieve broad flexibility, such a method is suitable for material webs / sheets that are completely coated with adhesive.

[0037] The object of the present invention is further achieved by a device for joining material webs or sheets with a heat-activated adhesive along a bonded seam. According to the present invention, the device includes a pair of unheated impact elements. A pair of unheated impact elements exists when one impact element acts against an abutment, i.e., a flat anvil, which then constitutes the second, mating impact element. The pair of unheated impact elements is configured to receive material webs or sheets arranged one above the other, with adhesive disposed between them. The device further includes a pulse-generating device configured to introduce an impact pulse into at least one of the impact elements to activate the adhesive. The impact pulse is at least one stroke of the impact element perpendicular to the material web or sheet, with a penetration period of less than 10 ms into the material web or sheet and the adhesive. The impact pulse acts on the material web or sheet, activating the adhesive and thereby forming a bonded seam within the effective area of ​​the impact element. The impact pulse is preferably generated by a driving device.

[0038] According to a more favorable development, the pretension force (Fv A device is provided for applying a pretension force (F) before the shock pulse is applied. v ) presses the impact elements against each other.

[0039] In a preferred embodiment, the pair of impact elements comprises at least a first impact element with an effective area having a shaped cross-section. It has also proven advantageous if the pair of impact elements comprises a second impact element with a flat effective area. An advantageous shaped cross-section has a flat profile bounded by two radii R2, with any contour shape and a width that at least covers the area of ​​the bonded seam. In a preferred embodiment, the shaped cross-section at the effective location that comes into contact with the 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 R2=1-4 mm, and has a width a, at least a=2 mm.

[0040] According to an advantageous embodiment, and as described in more detail above for a high-speed process, the first and / or second impact element are designed for use in a continuous feed web-guiding process. Alternatively, the first and / or second impact element can be designed as a tool that pivots toward the impact point or as a tool that temporarily moves along with the web during the gluing process, as is customary and commonly known for certain processing steps in web-guiding processes. Thus, the device according to the invention is suitable for installation in packaging systems and can also replace established sealing technologies. It is also advantageous if the pair of impact elements is made of hardened steel with a polished surface. Furthermore, each impact element includes an element for attachment to a drive device.

[0041] According to a first embodiment, the drive device acts on the first impact element, or according to a second embodiment, the drive device acts on the first impact element and the second impact element. 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 gear, the advantages of which have already been explained above. Also provided is a magnetic drive device for directly driving the impact element or the associated punch.

[0042] A further object of the invention relates to the use of an impact press as explained above as a drive device for a device for joining material webs or sheets with a heat-activated adhesive.

[0043] Pneumatic impact presses are suitable not only 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, achieving uniform embossing results for all embossing processes of the same material. The pretension effect, which also plays an important role in the method according to the present invention, allows for precise positioning of the workpiece and prevents deformation. Using clamping systems, different embossing tools, such as machine stamps, machine type holders, and embossing units, can be fastened to these machines. An exemplary embossing press has an impact force of 6 kN.

[0044] Compared to established sealing methods such as thermal contact sealing or ultrasonic sealing, the method proposed by the present invention offers the following advantages: Low temperature tools, adiabatic bonding processes, Use with heat-sensitive products, Highly cost-effective and robust system and tool technology, purely mechanical and manually operated solutions (spring pretensioning) can be implemented, Extremely short process times, -Minimum seam width can be achieved, By using profile patterns on the tool, unique seam and embossing patterns can be obtained. - Conventional packaging formats (side seal bags, tube bags) can be realized. Very low energy requirements and therefore very energy efficient.

[0045] For comparison, heat pulse joining of material webs or sheets with thicknesses of 20-100 μm and typical seam lengths requires an electrically generated heat pulse of 0.8 seconds at 165°C. This corresponds to an energy consumption of 200 J when using sealing pliers. In contrast, joining using the method according to the present invention requires only 5 J of energy for the same seam length. This corresponds to an energy savings of 97.5%.

[0046] The above advantages are advantageous in the following application areas: Packaging processes using webs or sheets of material (for industrial, food, medical products) for both high-speed continuous applications and individual processes in decentralized production, - Fast processing speed makes it suitable for use in continuous processes. Use of recyclable and compostable films, Mobile applications using spring pretension to seal without electrical energy, medical technology for development support (on-site packaging of medical samples), disaster relief (sandbag sealing), Packaging in a dusty environment.

[0047] The invention is explained in more detail below on the basis of a description of an embodiment and its illustration in the associated drawings, in which: [Brief explanation of the drawings]

[0048] [Figure 1] 1 is a schematic diagram of the process sequence of a method according to the invention for joining material webs or sheets by thermal bonding; [Figure 2]1 is a schematic perspective view of an embodiment of an impaction element according to the invention, the effective area of ​​which has a flat profile cross-section bounded by two radii; [Figure 3] 1 is a schematic perspective view of an embodiment of a first impact element according to the invention, the effective area of ​​which has a flat profile cross-section; [Figure 4] 1 is a schematic perspective view of an embodiment of a second impact element according to the invention with a flat effective area; FIG. [Figure 5] 1A-1D are two schematic diagrams of an embodiment of an impact press. [Figure 6] 1 is a schematic side view of an embodiment of a continuous web directing process. [Figure 7] 10A-10C are two schematic diagrams of further embodiments of a continuous web directing process. [Figure 8] 1 is a schematic perspective view of an embodiment of a glued seam according to the invention on a tube; [Figure 9] 1 is a schematic perspective view of an embodiment of a glued seam according to the invention on a tube bag; FIG. [Figure 10] 1 is a side view of an embodiment of a device according to the present invention with joined webs or sheets of material; [Figure 11] 1 is a schematic enlarged view of a bonding location with bonded webs or sheets of material. DETAILED DESCRIPTION OF THE INVENTION

[0049] Figure 1 shows a schematic diagram of an embodiment of the process sequence of a method according to the invention for joining material webs / sheets 10 with a heat-activated adhesive 11 using impact pulses. The process sequence is shown in three steps starting from the left. First, a first impact element 2 is applied along the infeed path s z, along the arrows, to the surface of the material webs / sheets 10, between which an activated adhesive, i.e., a hot melt adhesive 11, is placed and moves until the effective profile 6 contacts the material webs / sheets 10. The two material webs / sheets 10 to be joined by an adhesive seam 12 rest on the surface of the second impact element 4, which in this case is configured as a flat anvil. The effective profile 6 is also flat and radially tapered in order not to damage the material webs / sheets 10.

[0050] In the second step, the first impact element 2 applies a pretension force F v , is pressed against the material web or sheet 10, and the hot melt adhesive 11 is positioned between the materials. Thus, under the resulting preload that compensates for the surface roughness and elasticity of the material structure, the pulse force F applied in the third step i results in activation of the hot melt adhesive 11, which is then briefly melted in the effective zone, thereby forming the adhesive seam 12.

[0051] Figure 2 shows a schematic perspective view of an embodiment of an impact element 2 according to the invention, which, as used in Figure 1, has a flat profile cross section tapering to two radii R2 to form an effective profile 6. In an exemplary effective profile 6, the preferred radii R2 are 1-4 mm, and the flat profile has a width of at least a = 2 mm.

[0052] Figure 3 shows a schematic perspective view of an embodiment of a first impact element 2 according to the invention, in which the effective area 6 has a flat profile cross-section, as shown in detail in Figure 2. The mounting openings 8 serve to receive tightening bolts (not shown here), by means of which the first impact element 2 is tensioned with a pretensioning force F v and pulse force F i The impact element 2 is fastened to an impact element holder 26 (see FIG. 5) of a machine that applies the impact element 2 to the first impact element 2.

[0053] Figure 4 shows a schematic perspective view of an embodiment of a second impact element 4 according to the invention with a flat anvil-shaped effective area 6. The second impact element 4 is fastened to an impact element holder 28 (see Figure 5).

[0054] 5 shows diagrammatically in two views an embodiment of an impact press 20, with which the method according to the invention can be carried out. Such an impact press 20 offers the particular advantage of being able to operate without electrical power and purely manually, in particular as a spring-loaded impact press according to the embodiment shown. z The force required for the feed movement along the v and pulse force F i The force required for is applied by the operator using the operating lever 24.

[0055] As shown in Figure 1, the adhesive seam 12 is produced between the second impact element 4, on which the plastic film 10 rests, and the first impact element 2, which is fastened to the second impact element holder 26. For this purpose, the operating lever 24 is actuated and the first impact element holder 26 is moved towards the second impact element holder 28 via the feed device 32 until the first impact element 2 inserted in the first impact element holder 26 comes into contact with the material web or sheet 10.

[0056] Further movement of the operating lever 24 increases the required pretension force F v is applied, and further movement of the operating lever 24 tensions the spring during that movement, creating a pulse force F i is applied to the material web or sheet 10 by activating the pulse generator 30. A glued seam 12 is thus created in the area of ​​the contact zone between the first impact element 2 and the second impact element 4. A return stroke of the second impact element holder 26 by a counter movement of the operating lever 24 releases the sealed, glued material web or sheet 10.

[0057] 6 shows a schematic side view of an embodiment of a continuous web guiding process, in which a material web or sheet 10 is unwound from a web roll 40. In the device 1 for joining material webs / sheets 10 by gluing, the material web / sheet 10 passes between a first impact element 2 and a second impact element 4, generating a glued seam 12 (in the example, the glued seam 12 has not yet formed). However, measures must be taken to ensure continuity of the web guiding process, particularly during application of the pretensioning force, but also during application of the impact pulse. This can be achieved, for example, by periodically advancing and retracting the device 1 in the direction opposite to the web guiding direction, or by providing a web storage area in front of the device 1 (both not shown but known from the prior art).

[0058] 7 shows a schematic side view of another embodiment of a continuous web guiding process. A pretensioning force is applied by pretensioning rollers 42, and the material web / sheet 10 passes between two pretensioning rollers 42. A pulsing device 30, specifically an impact mechanism, acts on one or both of the two pretensioning rollers 42, resulting in the creation of a bonded seam 12.

[0059] 8 shows a schematic perspective view of an embodiment of a bonded seam 12 according to the invention in a tube 14 formed from folded and joined sections of a material web 10. The tube 14 can advantageously be used as a sleeve package, in which the tube 14 is placed over another finished package.

[0060] Figure 9 shows a schematic perspective view of an embodiment of an additional adhesive seam 12 according to the invention, here on a tube bag 16. This comprises a tube 14, the ends of which are closed with transverse seams, as shown in Figure 8. This is usually performed on the second upper side after filling with the packaged product. At the same time, the bottom seam of the next tube bag 16, i.e. the lower adhesive seam 12, can be produced.

[0061] Figure 10 shows a schematic side view of an embodiment of the device 1 according to the invention during bonding of material webs / sheets 10 by forming a bonded seam 12. This is particularly evident in the enlarged view of Figure 11. The device 1 comprises impact elements 2, 4, which are shown after the return stroke, which release the bonded seam 12.

[0062] 11 shows a schematic enlarged view of an adhesive joint, in particular an adhesive seam 12 connected with a material web / sheet 10, which extends on both sides of the adhesive seam 12. The very low adhesive seam 12 in the effective zone and the hot melt adhesive 11 fused with the material web / sheet 10 are visible. The compression also occurs partly due to the fact that the material web / sheet 10 consists of a compressible or heat-sensitive material and its height is reduced by the impact pulse.

[0063] The hot melt adhesive 11 protruding in an undeformed state beside the adhesive seam 12 does not appear thick, as occurs in other heat sealing processes according to the prior art when liquid adhesive is squeezed out. This clearly demonstrates that the adhesive 11 is not excessively melted and displaced. Rather, the heat-affected area 13, i.e., its boundary to the unaffected material web / sheet 10 (and to the hot melt adhesive 11 insofar as it protrudes beyond the activation zone in the area of ​​the adhesive seam), is indicated by a dashed line and is limited to the area of ​​the adhesive seam 12. Thus, neither the material web / sheet 10 nor any areas outside the material web / sheet 10, e.g., the packaged product within the package, are affected by undesired heating. [Explanation of symbols]

[0064] 1 device 2. First Impact Element 4 Second Impact Element 6 Scope and Profile 8 Mounting opening 10 Material web / material sheet 11 Adhesives, heat-activated adhesives, hot melt adhesives 12 Bonded seams, vertical seams, horizontal seams 13 Heat Affected Area 14 tubes 16 tube bags 20 Impact Press 22 Stand 24 Operating lever 26 First impact element holder 28 Second Impact Element Holder 30 Pulse generation (device) 32 Supply Device 40 Web Roller 42 Rolling tools, pretensioning rollers a Effective profile width R1 First effective profile radius R2 Second effective profile radius R3 Third effective profile radius F v Pretension force F i Pulse force and intensity of the shock pulse s z Delivery route

Claims

1. A glued seam for joining material webs or sheets (10) with a heat-activated adhesive (11), wherein an impact pulse in the form of a stroke movement of at least one of a pair of unheated impact elements (2, 4) acts perpendicularly on the material webs or sheets (10) arranged one above the other, the adhesive (11) being located between the material webs or sheets (10), and the penetration time of at least one of the impact elements (2, 4) into the material web or sheet (10) is less than 10 ms, and a glued seam (12) is formed. is formed by the shock pulse, at least partially penetrates the adhesive (11) and heat activates the adhesive (11), the heat activation is limited to the area of ​​the bonded seam (12), the height of the resulting bonded seam (12) is less than the height of both material webs or sheets (10), all of the liquefied adhesive (11) participates in the formation of the bonded seam (12), and the area of ​​the liquefied adhesive (11) remains limited to the bonded seam (12).

2. 2. The glued seam according to claim 1, wherein the heat-activated adhesive (11) is applied to at least one of the material webs or sheets (10) at least in the area of ​​the glued seam (12).

3. 3. The adhesive seam according to claim 1, wherein the heat-activated adhesive (11) is arranged between the material webs or sheets (10) without connecting to the material webs or sheets (10) before applying the shock pulse, at least in the area of ​​the adhesive seam (12) to be created.

4. The adhesive seam according to any one of claims 1 to 3, wherein the material webs or sheets (10) are joined in the edge area by the adhesive seam (12), thereby forming a tube (14) by forming a longitudinal seam.

5. The bonded seam according to any one of claims 1 to 4, wherein the tube (14) is closed by a bonded seam (12), thereby forming a transverse seam and producing a tube bag (16).

6. The glued seam according to any one of claims 1 to 5, wherein the heat activated adhesive (11) is a hot melt adhesive.

7. The glued seam according to any one of claims 1 to 6, wherein the material web or sheet (10) consists of paper or paper material.

8. 1. A method for joining material webs or sheets (10) with a heat-activated adhesive (11), the material webs or sheets (10) being joined along a bonded seam (12), characterized in that an impact pulse in the form of at least one stroke movement of a pair of unheated impact elements (2, 4) arranged one above the other acts perpendicularly on the material webs or sheets (10), with a penetration time of at least one of the impact elements (2, 4) into the material webs or sheets (10) and the adhesive (11) of less than 10 ms, whereby the adhesive (11) is activated and the bonded seam (12) is formed, followed by at least one return stroke of the impact elements (2, 4).

9. In a step preceding the impact pulse, the material web or sheet (10) and the adhesive (11) are subjected to a pretension force F ｖ 9. The method according to claim 8, wherein the material web or sheet (10) and the adhesive (11) are pressed against each other between the pair of impact elements (2, 4) at a constant speed, after which the impact pulse of at least one of the actuated impact elements (2, 4) or the impact pulse transmitted by at least one of the impact elements (2, 4) acts on the material web or sheet (10) and the adhesive (11).

10. 10. The method according to claim 8 or 9, wherein the mechanical drive of the impact element (2, 4) is directly effective or the impact pulse is transmitted indirectly by means of a spring force, a falling weight, a magnetic drive or a cam gear.

11. Method according to any one of claims 8 to 10, wherein the shock pulse is applied by the upper impact element (2) or by both counter-acting impact elements (2, 4).

12. 12. The method according to claim 8, wherein the heat-activated adhesive (11) is disposed between the material webs or sheets (10) at least in the area of ​​the bonded seam (12) to be created before applying the shock pulse.

13. 13. The method according to any one of claims 8 to 12, wherein the heat-activated adhesive (11) is applied to at least one of the material webs or sheets (10) at least in the area of ​​the glued seam (12).

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

15. 15. The method of claim 14, wherein a strip of adhesive (11) is supplied together with the web or sheet of material and positioned between the overlapping edges of the web or sheet of material during the formation of the tube (14) from the web or sheet of material.

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

17. 17. The method according to claim 16, wherein the opposing impact elements (2, 4) are used in 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. A method according to any one of claims 8 to 18, wherein the web or sheet of material consists of paper or paper material.

20. A device for joining material webs or sheets (10) with a heat-activated adhesive (11) along a glued seam (12), comprising: the device (1) comprises a pair of unheated impact elements (2, 4) arranged one above the other and configured to receive the material web or sheet (10), the adhesive (11) being between the material web or sheet (10), a pulse generating device (30) being provided for introducing the impact pulse to at least one of the impact elements (2, 4) in order to activate the adhesive (11), the penetration time of at least one of the impact elements (2, 4) into the material web or sheet (10) and the adhesive (11) being less than 10 ms, the impact pulse acting on the material web or sheet (10) and activating the adhesive (11) thereby forming the bonded seam (12) within the effective area of ​​the impact elements (2, 4).

21. Pretension force (F ｖ ) is applied before the shock pulse is applied. ｖ 21. The device according to claim 20, wherein a pressure plate is used to press the impact elements (2, 4) against each other.

22. 22. A device according to claim 20 or 21, wherein the shaped cross section (6) is formed as a flat profile bounded by two radii R2, with a width that at least covers the area of ​​the glued seam (12).

23. The device according to any one of claims 20 to 22, wherein the first impact element (2) and / or the second impact element (4) are designed using a web-guided process with continuous feeding.

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

25. The device of any one of claims 20 to 24, wherein the pulse generating device (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 any one of claims 20 to 25.

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