Device and method for producing layered strips and layered strip arrangement, in particular for use in the manufacture of hygiene articles

Abstract

Method for producing layered tapes (T1, T2) comprising the following: - Feeding a first layer (L1) in a machine direction, wherein the first layer (L1) comprises a paired first and a second strip (L1A, L1B) extending in the machine direction (MD) and arranged side by side in a transverse direction (CD) perpendicular to the machine direction (MD), - Feeding a second layer (L2) in the machine direction (MD), wherein the second layer (L2) comprises a paired third and a fourth strip (L2A, L2B) extending in the machine direction (MD) and arranged side by side in the transverse direction (CD), - Placing the second layer (L2) on top of the first layer (L1), forming a first stack (S1) comprising the first strip (L1A) and the third strip (L2A) and a second stack (S2) comprising the second strip (L1B) and the fourth strip (L2B), the first stack (S1) and the second stack (S2) being arranged side by side in the transverse direction (CD), - Feeding a third layer (L3) in the machine direction (MD), wherein the third layer (L3) extends in the machine direction (MD) and in the transverse direction (CD) such that it overlaps one (S1) from the first stack (S1) and the second stack (S2) and at least part of the other (S2) from the first stack (S1) and the second stack (S2), - Connecting the third layer (L3) with the one (S1) from the first stack (S1) and the second stack (S2), forming a first layered band (T1), and removing the first layered band (T1), - Feeding a fourth layer (L4) in the machine direction (MD), wherein the fourth layer (L4) extends in the machine direction (MD) and in the transverse direction (CD) such that it overlaps the other (S2) from the first stack (S1) and the second stack (S2), - Combining the fourth layer (L4) with the other from the first stack (S1) and the second stack (S2), forming a second layered band (T2), and removing the second layered band (T2), - Merging the first layered band (T1) with the second layered band (T2) so that the third layer (L3) of the first layered band (T1) overlaps the other from the first stack (S1) and the second stack (S2) and the fourth layer (L4) of the second layered band (T2) overlaps the one from the first stack (S1) and the second stack.

Description

[0001] The present invention relates to the production of layered tapes, in particular for use in the manufacture of hygiene products. State of the art

[0002] Layered tapes (so-called "laminates") are frequently used in the production of multiple sections or parts of hygiene products. Side panels of hygiene products such as diapers are an example of the use of laminates in hygiene product manufacturing. These side panels are made of stretchable laminates that incorporate an elastic film in their layered structure. Since the elastic film is more expensive than other materials used in the laminate (usually nonwovens), the design of the side panels aims to minimize the amount of elastic film required, taking into account the performance requirements of the side panel. This typically results in the elastic film being applied across a portion of the laminate's width, meaning the laminate's thickness is not uniform in the transverse direction.How this manifests itself largely depends on the width ratio between thicker and thinner sections of the laminate: For small side panels, for example for baby diapers, this ratio is usually high, which means that the imbalance in the tape material is very low and the latter can be easily and effectively wound into a roll after production and kept ready for further processing.

[0003] However, if side panels are designed for larger applications, such as diapers for overweight individuals, the above ratio shifts towards lower values ​​because the width of the elastic film required to achieve the desired performance represents a much smaller proportion of the total width of the tape material. Consequently, the resulting tape material is significantly unbalanced along the transverse direction, making it very difficult to wind into a roll for storage. In other words, the thickness profile across the cross-section of the tape material leads to uneven winding radii and increasingly inclined winding surfaces, resulting in irregular winding of the tape material.

[0004] From DE 692 09 089 T2 a pre-laminated composite tape is known which has at least one tape carrier made of porous paper which is coated on one side with a release coating 15) made of a solvent-free, radiation-cured silicone which is applied directly to the paper.

[0005] From US patent 4,801,480 A, a composite adhesive tape system for joining surfaces, parts, and the like is known, comprising a main fastening tape section coated with an adhesive, a target tape section, and a release tape section covering the target tape section, as well as a centrally arranged layer covering part of the release tape and partially folded under the target tape section, and methods for manufacturing and using the described tape system. Object of the invention

[0006] The object of the invention is to overcome the aforementioned technical problems. In particular, the object of the invention is to provide a balanced winding of strip materials that are uneven in the transverse direction. Summary of the invention

[0007] The object of the invention is solved by a method according to claim 1, a device according to claim 10 and a layered strip arrangement according to claim 15. Brief description of the characters

[0008] Further features and advantages of the invention will become apparent from the following description with reference to the accompanying figures, which are provided only as a non-limiting example, wherein: • Fig. 1 a schematic representation of a device according to the invention and • Fig. 2 is a schematic representation of process steps according to the invention and includes sections I to VIII, which are also in Fig. 1 are reproduced to illustrate the relevant procedural steps in relation to the device. Fig. 1. To be determined locally. Detailed description

[0009] Reference numeral 1 in Fig. Reference numeral 1 designates a device for producing layered strips according to the invention. In various embodiments, the device 1 comprises an anvil wheel 2, which acts as a functional hub that receives the output from processing devices or units that are part of the device 1 or prepares the input for them. The anvil wheel 2 is essentially configured as a rotating drum that is rotatable about an axis CD12 and comprises a circumferential surface 2A that is perforated to allow air to be drawn in from the outside, so that layers placed onto the anvil wheel 2 by the aforementioned processing devices or units are held on the surface 2A itself. The suction effect is primarily effective with respect to gas-tight or substantially gas-tight layers such as stretchable films.If the layer in question is a nonwoven fabric, the effect of the suction action with regard to holding the layer(s) on surface 2A is minimal and, in any case, negligible compared to the layer tension in the machine direction MD, which holds the layer in question on surface 2A anyway.

[0010] It should be noted that the anvil wheel 2 allows for the determination of a machine direction MD, which is a direction perpendicular to the axis CD12, and a transverse direction CD, which is also perpendicular to the machine direction MD. The machine direction is generally a working direction for the processing devices or units that form the device 1 and can even be variable in orientation as the output of the processing device or unit approaches the anvil wheel 2 or as the input of the processing device or unit leaves the anvil wheel 2, but it still remains perpendicular to the axis CD12. The transverse direction CD runs perpendicular to the machine direction MD and is therefore parallel to the axis CD12. Essentially, the transverse direction CD is a reference direction for certain actions performed on the inputs to or outputs from the processing units or devices as they move in the machine direction.When referenced or shown in the figures, direction R denotes a radial direction that intersects surface 2A.

[0011] The device 1 further comprises: - a first layer feed device 4, which is configured to feed a first layer L1 in the machine direction MD to the anvil wheel, wherein the first layer L1 comprises a paired first and a second strip L1A, L1B ( Fig. 2, Section I), which extend in the machine direction MD and are arranged side by side in the transverse direction CD, - a second layer feed device 6, which is used to feed a second layer L2 ( Fig. 2, Section I) is arranged in the machine direction MD to the anvil wheel 2, wherein the second layer L2 comprises paired third and fourth strips L2A, L2B, which extend in the machine direction MD and are arranged side by side in the transverse direction CD, wherein the second layer feed device 6 is further arranged to feed the second layer L2 onto the first layer L1 to form a first stack S1 comprising the first strip L1A and the third strip L2A, and a second stack S2 comprising the second strip L1B and the fourth strip L2B, - a third layer feed device 8, which is used to feed a third layer L3 ( Fig. 2, Section II) is arranged in the machine direction MD such that it overlaps the first stack S1 or the second stack S2 (stack S1 in the embodiment shown in the figures) and at least a part of the other, i.e., the second stack S2 or the first stack S1. Preferably, the layer L3 is laid such that it completely covers both stacks S1 and S2, as shown in Fig. 2, Section II can be seen; - a first connecting unit 10 ( Fig. 2, Section III), which is set up to connect the third layer L3 with the one from the first stack S1 and the second stack S2, thereby forming a first layered band T1, - a first take-off unit 12, which is set up to take off the first layered strip T1 from the anvil wheel 2 after it has been formed by the connecting unit 10, - a fourth layer feeder 14 ( Fig. 2, Section IV), which is arranged to feed a fourth layer L4 in the machine direction MD such that it overlaps the other layer from the first stack S1 and the second stack S2 (the latter in the embodiment shown in the figures), - a second connecting unit 16 ( Fig. 2, Section VI), which is set up to join the fourth layer L4 with the other from the first stack S1 and the second stack S2 (whereby the joining concerns stack S2), thereby forming a second layered band T2, - a second take-off unit 18, which is set up to take off the second layered strip T2 from the anvil wheel 2, and - a merging unit 20 ( Fig. 2, Section VII), which is arranged to merge the first layered volume T1 with the second layered volume T2 such that the third layer L3 of the first layered volume T1 overlaps the second stack S2 (generally the other one from the first stack S1 and the second stack S2) and the fourth layer of the second layered volume overlaps the first stack S1 (generally the one from the first stack S1 and the second stack S2).

[0012] Preferably, the merging unit 20 interacts with a transfer conveyor 22, which sufficiently extends the path of belt T2 so that belt T1 is guided in such a way that it merges with belt T2. The final overlap pattern between the stacks S1 and S2 is shown in Fig. 2, Section VII. Such a design is preferred because it is optimal for subsequent winding of the arrangement of the layered strips L1, L2 into a roll 24, see Fig. 2, Section VIII.

[0013] As a general remark, the significance of which will become apparent from the following revelation, the schematic views from which Fig. Figure 2 provides a reference representation of what happens to layers L1-L4 during the various process steps, and this is in no way intended to be restrictive or a complete illustration of actual processing conditions of the embodiments. For example, while stacks S1 and S2 are shown here as separated by a substantial gap, in embodiments such a gap may be comparatively smaller or virtually zero, depending on the processing conditions. Furthermore, although the thickness of the layers is shown as generally uniform, it may vary depending on the materials involved and / or certain design choices. Similarly, the dimension of layers L1-L4 in the transverse direction CD (i.e.,in width) in reality may differ from the schematic representation above, either due to deliberate design decisions that provide for asymmetrical stacks S1 and S2, or due to layer properties, for example the elastic elongation of layer L2 (which can also influence the layer thickness).

[0014] In preferred embodiments, layers L1, L3 and L4 consist of or comprise a nonwoven material, typically a material that is not designed to be processed by stretching / elastic elongation, for example in the transverse direction CD.

[0015] In such embodiments, layer L2 consists of or comprises a stretchable material, for example a stretchable film that can be stretched in the transverse direction CD (and also in the machine direction MD, although the latter may not be of interest for a number of applications).

[0016] Accordingly, the layer feed devices 4, 8, 14 and the take-off units 12, 18 are generally designed as feed units, wherein the material layer travels a path through one or more rollers (drive rollers and deflection rollers) while being unwound or otherwise taken off from a buffer comprising a roll, a coil, or a stack of layers. The same applies, inter alia, to the merging unit 20 and the transfer conveyor 22.

[0017] Purely by way of example, and without the description or the figure implying any limitation with regard to embodiments of the invention, the following is shown: Fig. 2 An exemplary arrangement of the devices 4, 8, 12, 14, 18, 20, 22, wherein the rollers defining the path traversed by the layers L1, L3, L4 and the strip T1 are designated with the same reference numerals as the device to which they belong, supplemented by a consecutive identifier (i.e., 1, 2, 3, etc.), separated by a slash. The corresponding direction of rotation is assigned to the representation of each roller. Accordingly: - The first layer feed device 4 comprises a first roller 4 / 1 and a second roller 4 / 2, both configured as deflection rollers, with roller 4 / 2 also configured as a depositing roller for depositing layer L4 onto the anvil wheel 2 (and on top of any further layers that may be located thereon). The first layer L1 is accordingly unwound from a roll, a coil, or a stack of layers; - The third layer feed device 8 comprises a first roller 8 / 1, a second roller 8 / 2 and a third roller 8 / 3. The roller 8 / 1 is a winding bearing shaft in which a winding C3 of layer L1 (e.g. a nonwoven fabric) is mounted, the roller 8 / 2 is a deflection roller, and the roller 8 / 3 is a lay-down roller (which also imparts some deflection to layer L3), which is arranged to lay the layer L3 - unwound from the winding C3 - onto the anvil wheel 2 (and on top of other layers that may be located on it); - the take-off unit 12 comprises a first roller 12 / 1 and a second roller 12 / 2, the former being a take-off roller and the latter a deflection roller; - the fourth layer feed device 14 comprises a first roller 14 / 1, a second roller 14 / 2, a third roller 14 / 3 and a fourth roller 14 / 4, wherein the rollers 14 / 1 to 14 / 3 are deflection rollers, while the roller 14 / 4 is a discharge roller which is arranged to discharge the layer L4 - pulled from a layer stack PS4 - onto the anvil wheel 2 (and on top of other layers that may be located on it), - the take-off unit 18 comprises a single roller 18 / 1 (a take-off roller), but it works together with the transfer conveyor 22 (rollers 22 / 1 and 22 / 2) to transfer the belt T2 to a merging point with the belt T1, - The merging unit 20 also has a first and a second roller 20 / 1 and 20 / 2, the latter being a lay-down roller configured to place the strip T1 onto the newly formed strip T2. It should be noted that the merging unit 20 can be designed as a section of the take-off unit 12, since it actually takes over the strip T1 from the latter: Accordingly, the merging unit 20 can simply be designed as an extension of the take-off unit 12, configured to pull the strip T1 to the point where strips T1 and T2 meet ( Fig. 2, Section VII).

[0018] Based on the design of the above layer feed devices, removal units and the merging unit, one or more of the aforementioned rollers may also be equipped with layer drive functions, i.e. they may be set up to pull off the respective layer L1, L2, L3, L4 from the corresponding storage device (winding, layer stack, etc.).

[0019] With regard to the processing of layer L2, in the preferred embodiments, where the layer comprises an elastically stretchable film, the layer feed device 6 is designed differently from the other layer feed devices 4, 8, 14. In particular, the layer feed device 6 is configured as a stretching device designed for stretching layer L2 in the transverse direction CD. For this purpose, a first roller 6 / 1 deflects layer L2 and conveys it to a stretching roller 6 / 2. The stretching roller 6 / 2 can be configured as a conventional single-track stretching device, designed for processing a single strip of layer L2 and stretching it in the machine direction, or as a double-track stretching device, as disclosed in European patent application No. 21189781.4 in the name of the same applicant.The latter is configured to simultaneously process two parallel strips of stretchable material to create a stretch in the transverse direction CD. In both cases, the stretchable material is held in a manner known per se by means of suction devices at the circumferential edges of clamping discs that have a variable mutual distance in the transverse direction CD. This forces the stretchable material to accommodate the change, in particular the increase, in the mutual distance between the clamping discs as it wraps around them, thereby undergoing a stretch in the transverse direction CD. When layer L2 is finally laid down in a stretched state onto layer L1, the transverse stretch of layer L2 is maintained by the suction of layer L2 (which also presses layer L1 onto the anvil wheel 2).The suction effect is achieved through the increased gas tightness of the stretchable layer L2 compared to the nonwoven fabric of layer L1, whereby layer L2 retains the stretched state produced by the stretching roller 6 / 2.

[0020] If the stretching roller 6 / 2 is designed as a single-track stretching device, it is advantageous to provide a cutting device 26 downstream of the layer feed unit 6 on the anvil wheel 2 in order to divide the stacked layers L1, L2 into paired first and second strips L1A, L1B, L2A, L2B and accordingly into stacks S1, S2.

[0021] Alternatively, if the stretching roller 6 / 2 is designed as a double-track stretching device as mentioned above, the first layer feed device 4 is also provided with a paired arrangement, whereby the layer L1 is already fed separately into paired strips L1A, L1B and the paired strips L2A, L2B are individually stretched from the roller 6 / 2 and individually placed onto the paired strips L1A, L1B, as shown in the Fig. 2, Sections I to VII. In such embodiments, the cutting device 26 may not be provided, since the stacks S1, S2 are practically pre-formed before layer L2 is applied to layer L1. However, in some embodiments, the cutting device 26 may still be provided, especially if the layer feed device 4 is not arranged in pairs. In these embodiments, strips L2A and L2B are individually applied to the uniform layer L1 in a stretched state, from which strips L1A and L1B are then separated by the cutting device 26 acting between strips L2A and L2B, without interacting with them.

[0022] The joining units 10 and 16 are preferably designed as ultrasonic joining units configured to apply a weld pattern to the strip to be layered, which is then joined on the anvil wheel 2. The joining units 10 and 16 are typically configured to provide spot weld patterns that permanently join the layers L1, L2, L3 (joining unit 10) and L1, L2, L4 (joining unit 16), respectively, while allowing layer L2 to shrink back to its original unstretched state after joining and after the removal of the condition maintaining the stretch – in this case, the suction effect on the anvil wheel 2. This suction effect is typically removed when the newly formed strips T1, T2 are taken off the anvil wheel 2, thus eliminating the suction that holds the strip(s) on the anvil wheel 2 itself.In a manner known per se, the bands T1, T2 are given a three-dimensionally textured elastic core by shrinking back the layer L2 (of each individual strip) to its original unstretched shape.

[0023] Overall, the device 1 according to the invention operates according to a method for producing layered tapes (or laminates), which is itself part of the invention.

[0024] In various embodiments, the inventive method for producing layered strips T1, T2 comprises (passage through Fig. 2 clockwise) The following: - Feeding the first layer L1 in machine direction MD, wherein the first layer L1 comprises a paired first and a second strip L1A, L2A, which extend in machine direction MD and are arranged side by side in transverse direction CD, - Feeding the second layer L2 in the machine direction MD, wherein the second layer L2 comprises a paired third and a fourth strip L2A, L2B, which extend in the machine direction MD and are arranged side by side in the transverse direction CD, - Placing the second layer L2 on top of the first layer L1, forming the first stack S1 comprising the first strip L1A and the third strip L2A, and the second stack S2 comprising the second strip L1B and the fourth strip L2B, with the first stack S1 and the second stack S2 arranged side by side in the transverse direction ( Fig. 2, Section I), - Feeding the third layer L3 in the machine direction MD, wherein the third layer L3 extends in the machine direction MD and in the transverse direction CD such that it overlaps the first stack S1 or the second stack S2 (here the stack S1) and at least a part of the other from the first stack S1 and the second stack S2 (here the stack S2) - Fig. 2, Section II, - Connecting the third layer L3 with one from the first stack S1 and the second stack S2 (in view of the above, the connecting concerns stack S1), thereby forming the first layered band T1 ( Fig. 2,

[0025] Section III), and removal of the first layered band T1 ( Fig. 2, Section IV), - Feeding a fourth layer L4 in machine direction MD, wherein the fourth layer L4 extends in machine direction MD and in transverse direction CD so that it overlaps the other layer from the first stack S1 and the second stack S2 (here the stack S2) - Fig. 2, Section V, - Combining the fourth layer L4 with the other from the first stack S1 and the second stack S2 (in view of the above, the combining concerns stack S2), thereby forming the second layered band T2, and removing the second layered band T2 ( Fig. 2, Section VI), - Merging the first layered volume T1 with the second layered volume T2, so that the third layer of the first layered volume overlaps the other from the first stack S1 and the second stack S2 (here the stack S2) and the fourth layer of the second layered volume overlaps the one from the first stack S1 and the second stack S2 (here the stack S1).

[0026] The first layer L1 is fed in the machine direction MD by the first layer feeder 4: The layer L1, in preferred embodiments a nonwoven fabric, is pulled from a supply or buffer (e.g., a roll or a stack of layers) and placed onto the anvil wheel 2. Due to the tension exerted on the layer L1, the layer L1 adheres to the surface 2A (the suction effect, as mentioned, results in a minimal adhesive force, if any), whereby the surface 2A – up to the extent of the layer L1 – is lined with the layer L1 itself. As noted above, the layer L1 can be fed as a single, uniform layer, with the strips L1A and L1B still needing to be cut from each other or already divided into the strips L1A and L1B.

[0027] Next, the second layer L2 is fed in the machine direction MD by the second layer feed device 6. In preferred embodiments, where layer L2 is a stretchable (elastically stretchable) material, the feed device 6 stretches layer L2 in the transverse direction before it is applied to layer L1, as disclosed above. This stretching is retained even after layer L2 (whether a single layer or arranged in paired strips) leaves the stretching roller 6 / 2: Due to the suction effect on surface A2, layer L2 adheres to layer L1, also utilizing the increased gas tightness of layer L2 compared to layer L1.This results, regardless of whether the strips have already been cut from each other or not, in a stacking of the first strip L1A and the third strip L2A, as well as a stacking of the second strip L1B and the third strip L2B.

[0028] Subsequently, if layer L1 and / or layer L2 are not fed in as paired strips or placed on the anvil wheel 2, a cutting phase is provided in which the cutting unit 26 separates the layer(s) in the machine direction MD, thereby forming the first stack S1 and the second stack S2 as separate stacks.

[0029] The third layer L3 is fed in the machine direction MD via the third layer feed device 8: Layer L3 is pulled from the roll C3 (or corresponding layer stack) and placed by the unloading roll 8 / 3 onto the stacks S1 and S2. The third layer L3 extends in the transverse direction CD such that it overlaps the first stack S1 and at least part of the second stack S2 (the reverse is of course also possible), as shown in Fig. 2, Section II shown. The extent of the overlap between the stack S2 and the layer L3 is variable and depends on the dimension of the layer L3 in the transverse direction CD, but it is preferred that the layer L3, in addition to completely covering the stack S1, also completely covers the stack S2 and essentially terminates at the edge of the stack S2 itself.

[0030] The stretching of layer L2 in the transverse direction CD is maintained by the suction effect described above on surface A2 during the application of layer L3, which, however, adheres to layers L2, L1 and anvil wheel 2A primarily due to its tension in the machine direction MD, as this prevents the suction from the anvil wheel 2 from penetrating layer L2.

[0031] These are the conditions under which the third layer L3 joins to the first stack S1, forming the first layered band T1 ( Fig. 2, Section III). As noted above, the joining or bonding is preferably carried out as ultrasonic bonding over a dot-like pattern. The ultrasonic bonding is achieved by the interaction between a sonotrode of the joining unit 10 and the anvil wheel 2 on which the layers L1, L2, L3 are arranged.

[0032] The joining process affects only stack S1, while stack S2 remains adhered to the anvil wheel 2, its layers not yet joined. The stretching of layer L2 is maintained for precisely the same reasons as mentioned above, and it is generally maintained as long as layer L2, or a portion thereof (e.g., a single strip from the initial two), along with any intervening layers, remains adhered to the anvil wheel 2.

[0033] The layered strip T1 is formed accordingly and is now ready for removal by the first removal unit 12. At this stage, the suction effect exerted on the surface 2A is overcome, thereby eliminating the transverse stretching of layer L2 of strip T1. Strip T1 then passes through a buffer section via the removal unit 12 and the joining unit 20, the latter preferably being designed as the end section of the removal unit 12. In some embodiments, the joining unit 20 and the removal unit 12 can thus be combined into a single device or unit.

[0034] The fourth layer L4 is fed in the machine direction MD in a manner similar to the feeding of the third layer L3 and is carried out via the fourth layer feed device 14. This device pulls the layer L4 (preferably a nonwoven material, even more preferably identical to the material of layer L3) from the layer stack PS (or correspondingly from a roll) and places it on the anvil wheel 2 above the remaining stack S2. The layer L4, similar to the layer L3, is held on the anvil wheel 2 by its tension in the machine direction.

[0035] As with layer L3, layer L4 extends across stack S2 in the transverse direction CD, thus overlapping stack S2 and extending further in the transverse direction. Fig. 2, Section V. Preferably, the dimension of layer L4 in the transverse direction CD I is identical to that of layer L3.

[0036] These are the conditions under which the fourth layer L4 joins the second stack S2, forming the second layered band T2 ( Fig. 2, Section VI). As with strip T1, the joining or bonding is preferably carried out as ultrasonic bonding over a dot-like pattern. The ultrasonic bonding is achieved by the interaction between a sonotrode of the joining unit 16 and the anvil wheel 2, on which the layers L1, L2, and L4 are arranged. The joining only affects stack S2, since stack S1 has already been removed with strip T1. The stretching of layer L2 is maintained for exactly the same reasons as stated above, and it is maintained as long as layer L2, together with any intervening layer(s), adheres to the anvil wheel 2.

[0037] The layered belt T2 is formed accordingly and ready for removal by the first removal unit 18, whereby the transverse stretching of layer L2 of the stack S2 is also released during removal. The transfer conveyor provides the buffer section introduced by the combination of the removal unit 12 and the merging unit 20 and directs belt T2 to a merging point at the discharge roller 20 / 2 of the merging unit. Here - Fig.2, Section VII - the tapes T1 and T2 are stacked such that the third layer L3 of tape T1 overlaps the second stack S2, and the fourth layer L4 of the second stacked tape T2 overlaps the first stack S1. Note that, due to the layer arrangement, without any twisting by which tape T1 is reversed, when tapes T1 and T2 are finally stacked, portions of layer L4 (or L3) are usually alternately on opposite sides of stacks S1 and S2, while layer L3 (or L4) is consistently on the same side of stacks S1 and S2 and partially in contact with layer L4 (or L3). In any case, a quasi-uniform four-layer stacked tape arrangement is obtained, which can easily be wound onto a reel or reel.Roll 24 can be wound without any significant lack of balance in the transverse direction CD (the bridging sections of layers L3 and L4, located solely between stacks S1 and S2, do not affect the balance of the stacked tape arrangement). In other words, while each of the stacked tapes T1, T2 is individually unbalanced with respect to the number of layers in a transverse direction, the resulting tape arrangement is nevertheless balanced, allowing for a balanced winding of the stacked tapes to roll 24 or, alternatively, a balanced folding of the tape arrangement into a layer stack.

[0038] Tapes T1 and T2 can be used for a wide variety of purposes, particularly in the manufacture of hygiene products. One preferred application is the production of diapers for overweight individuals, where tapes T1 and T2 can be used to create the so-called "ears" of the diaper. These are stretchable waistband sections that protrude laterally from the chassis and are designed to connect to parts of the chassis itself to close the diaper's waist. Tapes T1 and T2 can be unwound together from roll 24 and cut into sections that form the ears. The cross-sections of tapes T1 and T2 are symmetrical with respect to the machine direction MD, so they can readily be used as pre-products for the left and right ears, respectively (e.g., T1 as the pre-product for the right ear, T2 as the pre-product for the left ear).

[0039] The inventive method and apparatus can also be used to produce layered strips, such as strips T1 and T2, without elastic or stretchable properties. In such embodiments, layer L2 is replaced by a non-stretchable layer, and the second layer feed device 6 is designed like the other layer feed devices. Otherwise, the method steps and the apparatus 1 remain unchanged.

[0040] Of course, while the inventive principle remains the same, the structural details and embodiments can differ greatly from those described and illustrated by way of example, without deviating from the scope of the present invention.

Claims

[1] Method for producing layered tapes (T1, T2) comprising the following: - Feeding a first layer (L1) in a machine direction, wherein the first layer (L1) comprises a paired first and a second strip (L1A, L1B) extending in the machine direction (MD) and arranged side by side in a transverse direction (CD) perpendicular to the machine direction (MD), - Feeding a second layer (L2) in the machine direction (MD), wherein the second layer (L2) comprises a paired third and a fourth strip (L2A, L2B) extending in the machine direction (MD) and arranged side by side in the transverse direction (CD), - Placing the second layer (L2) on top of the first layer (L1), forming a first stack (S1) comprising the first strip (L1A) and the third strip (L2A) and a second stack (S2) comprising the second strip (L1B) and the fourth strip (L2B), the first stack (S1) and the second stack (S2) being arranged side by side in the transverse direction (CD), - Feeding a third layer (L3) in the machine direction (MD), wherein the third layer (L3) extends in the machine direction (MD) and in the transverse direction (CD) such that it overlaps one (S1) from the first stack (S1) and the second stack (S2) and at least part of the other (S2) from the first stack (S1) and the second stack (S2), - Connecting the third layer (L3) with the one (S1) from the first stack (S1) and the second stack (S2), forming a first layered band (T1), and removing the first layered band (T1), - Feeding a fourth layer (L4) in the machine direction (MD), wherein the fourth layer (L4) extends in the machine direction (MD) and in the transverse direction (CD) such that it overlaps the other (S2) from the first stack (S1) and the second stack (S2), - Combining the fourth layer (L4) with the other from the first stack (S1) and the second stack (S2), forming a second layered band (T2), and removing the second layered band (T2), - Merging the first layered band (T1) with the second layered band (T2) so that the third layer (L3) of the first layered band (T1) overlaps the other from the first stack (S1) and the second stack (S2) and the fourth layer (L4) of the second layered band (T2) overlaps the one from the first stack (S1) and the second stack. [2] The method of claim 1, further comprising one of the following: - Winding the first layered band (T1) and the second layered band, which are joined together, into a roll (T2); - Fold the first layered band (T1) and the second layered band, which are joined together, to form a stack of layers. [3] Method according to claim 1, wherein the second layer (L2) comprises a stretchable material and wherein, in the method, the second layer (L2) is further stretched in the transverse direction (CD) before the second layer (L2) is applied to the first layer (L1), and the second layer (L2) is kept stretched in the transverse direction (CD) after the second layer (L2) has been applied to the first layer (L1). [4] Method according to claim 3, wherein the joining of the third layer (L3) with one of the first stack (S1) and the second stack (S2) is carried out while the second layer (L2) is held stretched in the transverse direction (CD). [5] Method according to claim 3, wherein the joining of the fourth layer (L4) with the other (S2) from the first stack (S1) and the second stack (S2) is carried out while the second layer (L2) is held stretched in the transverse direction (CD). [6] Method according to any of the preceding claims, wherein the first layer (L1) and the second layer (L2) are separated after the application of the second layer (L2) to the first layer (L1), thereby separating the first strip (L1A) from the second strip (L1B) and the third strip (L2A) from the fourth strip (L2B) and forming the first stack (S1) and the second stack (S2) accordingly. [7] Method according to any one of claims 1 to 5, wherein the feeding of a first layer (L1) in the machine direction (MD) comprises the feeding of a first and a second strip (L1A, L1B) which are paired and separated, and wherein the feeding of a second layer (L2) in the machine direction (MD) comprises the feeding of a third and a fourth strip (L2A, L2B) which are paired and separated. [8] Method according to claim 7, wherein when stretching the second layer (L2) in the transverse direction (CD) before applying the second layer (L2) to the first layer (L1) the third strip (L2A) and the fourth strip (L2B) are stretched individually. [9] Method according to any one of claims 3 to 8, wherein the stretching of the third strip (L2A) and the fourth strip (L2B) of the second layer (L2) is cancelled upon removal of the first layered strip (T1) or upon removal of the second layered strip (T2), whereby the joining of the first layered strip (T1) with the second layered strip (T2) takes place with the stretching of the third and fourth strips (L2A, L2B) of the second layer (L2) cancelled. [10] Method according to any of the preceding claims, wherein the first layer (L1), the third layer (L3) and the fourth layer (L4) each comprise a nonwoven material and wherein the third layer (L3) and the fourth layer (L4) have substantially the same dimensions in the transverse direction (CD). [11] Device for producing layered strips, comprising: - an anvil wheel (2), - a first layer feed device (4) which is configured to feed a first layer (L1) in a machine direction (MD) to the anvil wheel (2), wherein the first layer (L2) comprises a paired first and a second strip (L1A, L1B) which extend in the machine direction (MD) and are arranged side by side in a transverse direction (CD) perpendicular to the machine direction (MD), - a second layer feed device (6) configured to feed a second layer (L2) in the machine direction (MD) to the anvil wheel (2), wherein the second layer (L2) comprises paired third and fourth strips (L2A, L2B) extending in the machine direction (MD) and arranged side by side in the transverse direction (CD), wherein the second layer feed device (6) is further configured to feed the second layer (L2) onto the first layer (L1) such that a first stack (S1) comprising the first strip (L1A) and the third strip (L2A) and a second stack (S2) comprising the second strip (L1B) and the fourth strip (L2B) are formed, - a third layer feed device (8) which is configured to feed a third layer (L3) in the machine direction (MD) such that it overlaps one (S1) from the first stack (S1) and the second stack (S2) and at least a part of the other (S2) from the first stack (S1) and the second stack (S2), - a first connecting unit (10) which is set up to connect the third layer (L3) with one from the first stack (S1) and the second stack (S2), thereby forming a first layered band (T1), - a first take-off unit (12) which is set up to take off the first layered strip (T1) from the anvil wheel (2), - a fourth layer feed device (14) which is configured to feed a fourth layer (L4) in the machine direction (MD) such that it overlaps the other (S2) from the first stack (S1) and the second stack (S2), - a second connecting unit (16) which is set up to connect the fourth layer (L4) to the other (S2) from the first stack (S1) and the second stack (S2), thereby forming a second layered band (T2), - a second connecting unit (16) which is designed to connect the fourth layer (L4) to the other (S) from the first stack (S1) and the second stack (S2), thereby forming a second layered band (T2), - a second take-off unit (18) which is set up to take off the second layered strip (L2) from the anvil wheel (2), - a merging unit (20) which is set up to merge the first layered band (T1) with the second layered band (T2) such that the third layer (L3) of the first layered band (T1) overlaps the other from the first stack (S1) and the second stack (S2) and the fourth layer (L4) of the second layered band (T2) overlaps the one from the first stack (S1) and the second stack. [12] Device according to claim 11, wherein the second layer feed device (6) is a stretching device configured to stretch the second layer in the transverse direction (CD). [13] Device according to claim 12, wherein the second layer feed device is a double stretching device configured to simultaneously stretch the third strip (L2A) and the fourth strip (L2B) of the second layer (L2), which are paired, in a transverse direction. [14] Device according to claim 13, wherein the merging unit (20) is an extension of the first removal unit (12). [15] Layered strip arrangement produced by a method according to any one of claims 1 to 10, comprising a first layered strip (T1) and a second layered strip (T2), wherein the first layered band (T1) and the second layered band (T2) each comprise a first layer (L1) and a second layer (L2) placed on top of the first layer (L1), wherein the first layer (L1) comprises a first and a second stripe (L1A, L1B) and the second layer (L2) comprises a third and a fourth stripe (L2A, L2B), the first layered band (T1) comprises the following: - a first stack (S1) comprising the first strip (L1A) and the third strip (L2A), - a third layer (L3) placed on top of the second layer (L2) in such a way that it overlaps the first stack (S1) and is connected to the first stack (S1), - a fourth layer (L4) placed on top of the second layer (L2) in such a way that it overlaps the second stack (S2) and is connected to the second stack (S2), wherein the first layered band (T1) and the second layered band (T2) are joined together such that the third layer (L3) of the first layered band (T1) overlaps the second stack (S2) and the fourth layer (L4) of the second layered band (T2) overlaps the first stack (S1), and wherein the first layered band and the second layered band - wound into a roll (24) or - folded into a stack of layers.

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