Method and device for applying a stretched elastic material strip to a carrier material

Abstract

Main claim: A method for applying a stretched elastic material strip (4) to a carrier material (6), comprising the following steps, preferably in the specified order: - stretching an elastic material web (8) in the transverse direction, - optionally applying glue to at least one sub-region of the stretched material web (8), - dividing the stretched material web (8) into individual stretched material strips (4) by cutting the material web (8) in the transverse direction, - adapting the distance between the stretched material strips (4), and - applying the stretched material strips (4) to a carrier material (6).

Description

[0001] Description

[0002] Method and device for applying a stretched elastic material strip to a carrier material

[0003] The invention relates to a method and a device for applying a stretched elastic material strip to a carrier material.

[0004] In particular, the invention relates to the efficient and precise production and application of elastic material strips used for the production of hygiene products such as diapers or incontinence articles.

[0005] The object of the invention is to provide a method and a device that enable elastic material strips to be applied to a carrier material in a stretched state. The material strips are to be produced through precisely coordinated and compatible process steps and then glued or bonded to the carrier material. A further object of the invention is to adapt the spacing between the material strips during the application process to the feed rate of the carrier material.

[0006] In a preferred application, a stretched elastic material strip similar to a waistband is reliably applied to and bonded to a diaper or similar hygiene product to form a pocket-like overflow protection. After application, the material strip tends to shrink back, causing the material to "ruffle" or ripple or form accordion-like folds. It then preferably stands up on its own, forming the desired pocket when pressed against the skin of the baby or other wearer.

[0007] Of course, it may also be desirable in other applications to apply a stretched or pre-stressed strip of material in this state to a carrier or substrate and, in particular, to bond it by means of adhesive or glue.

[0008] With regard to the method, the above-mentioned object is achieved according to the invention by a method having the features of claim 1.

[0009] Accordingly, the invention comprises a method for applying a stretched elastic material strip to a carrier material, comprising the following steps, preferably in the order mentioned:

[0010] • Stretching an elastic material web in the transverse direction,

[0011] • optionally (but preferably) applying glue to at least a portion of the stretched material web,

[0012] • Dividing the stretched material web into individual stretched material strips by cutting the material web in the transverse direction,

[0013] • Adjusting the distance between the stretched material strips, and

[0014] • Applying the stretched material strips to a carrier material.

[0015] The associated device is defined in claim 18.

[0016] The features, objects and advantages of the invention mentioned here and below with regard to the method are transferred mutatis mutandis to the device / system and vice versa.

[0017] The advantages achieved by the invention are, in particular, that the glue is applied to the already stretched material web before it is separated into strips. This stretched state is maintained until the respective strip is applied to the carrier material, thus preventing any undesirable distortion of the glue application (with corresponding local fluctuations in the applied quantity and thickness).

[0018] Furthermore, the invention enables improved control over the stretching process of elastic material strips. The precise execution of the process and the use of the corresponding device achieve a high level of reproducibility in the stretching and subsequent glue application. This leads to consistent and reliable quality of the manufactured and applied material strips used in hygiene articles such as diapers or incontinence products.

[0019] A further advantage is the process's adaptability to meet different requirements regarding the stretching and placement of the material strips. The flexibility of the device allows the spacing between the strips to be varied as needed, enabling versatile application in various production environments.

[0020] Furthermore, the efficiency of the manufacturing process contributes to optimizing production costs. Precise control of stretching and targeted glue application minimize material consumption, which in turn contributes to cost-effective production.

[0021] Advantageous embodiments are the subject of the dependent claims and the following description.

[0022] Advantageously, the carrier material is transported on a first, preferably substantially horizontally oriented conveyor belt during the application of the respective material strip, whereby a machine direction and a transverse direction perpendicular thereto are defined.

[0023] The stretching of the elastic material web is preferably carried out by a stretching device comprising two divergently aligned rotating discs that grip the material web at its edges and stretch it transversely when rotated through a predetermined angle. This is a proven technology in itself.

[0024] It is advantageous if, after stretching, the material web is transferred to a second, horizontally aligned conveyor belt running counter to the machine direction and guided past a gluing device. This is preferably a vacuum conveyor belt that securely holds the material web, especially at the edges, to prevent it from shrinking back to its unstretched original position.

[0025] Advantageously, the glue / adhesive is applied to the stretched material web using a glue application head, which allows for continuous or time-pulsed application of glue across the entire width of the material web or across sections of it. An adjustable glue pattern can be applied to the material web in the transverse direction.

[0026] The stretched material web is advantageously cut by a combined cutting and repitching device comprising a cutting unit and a repitching unit in close proximity to one another.

[0027] In a conventional design, the cutting unit can have a driven cutting roller with cutting blades that cut the material web in the transverse direction.

[0028] In a preferred embodiment, the repitch unit can have a rotating roller with transfer heads that pick up the stretched material strips from the cutting unit and transfer them directly to the carrier material, thereby adjusting the spacing between the material strips. The spacing between the stretched material strips is preferably adjusted by deliberately varying the peripheral speed of the transfer heads in the repitch unit. The transfer heads are preferably equipped with vacuum suction to securely hold the material strips in the stretched state. In the overall process, it is advantageous for the stretched material strips to be deflected in the machine direction by the repitch unit and rotated by 180° ± 30° (= effective angle) so that the applied glue faces the carrier material when the material strips are applied.Thus, the material strips are applied to the carrier material in a stretched state and glued or bonded to it. The stretching device also preferably has an effective angle of 180° ± 30°.

[0029] To ensure a bond that can withstand loads as quickly as possible, the material strip is preferably pressed against the carrier material by a pressure device (at least) during application. This pressure can be achieved by a pressure roller mounted eccentrically on a rotating drum, which presses against the carrier material conveyor belt from below.

[0030] An alternative characterization of the general process steps in a preferred system configuration may be as follows:

[0031] 1. Unrolling an elastic material from a supply roll.

[0032] 2. Feeding the unrolled material web to a stretching device.

[0033] 3. Cross-stretching / cross-stretching the material web with the stretching device.

[0034] 4. Feeding the stretched material web to a gluing device.

[0035] 5. Apply glue to the stretched material web using the gluing device.

[0036] 6. Feeding the (glued and) stretched material web to a cutting and re-titching device.

[0037] 7. Transfer of a (glued and) stretched section (in the area of ​​the leading edge) of the material web to a transfer head of the cutting and repitching device.

[0038] 8. Cutting / separating the (glued and) stretched section with a cutting unit of the cutting and re-cutting device. 9. Changing the peripheral speed of the transfer head after the cutting process so that the speed of the carrier material is reached at the transfer point.

[0039] 10. Application / transfer of the (glued and) stretched section (= material strip) to the passing carrier material.

[0040] 11 . Optional (but preferred) pressing the material strip onto the carrier material at the moment of application.

[0041] Alternatively, glue application can be omitted in steps 4 / 5, and the gluing device can be omitted at this point. In this case, the stretched material web can be transferred directly from the stretching device to the cutting and repitching device (so that the associated conveyor belt can be particularly short or even eliminated). This can be the case, for example, if the material of the respective conveyor strip adheres naturally to the carrier material. Alternatively, glue / adhesive can be applied to the elastic material web or the already cut material strips at another point in the process chain, e.g., after cutting or during speed adjustment. Alternatively or additionally, glue / adhesive can be applied to the carrier material.

[0042] An embodiment of the invention is explained below with reference to the accompanying drawings. They show, in highly simplified, schematic representations:

[0043] FIG. 1 shows a longitudinal section through a system for applying a stretched elastic material strip to a carrier material,

[0044] FIG. 2 shows a detail from FIG. 1, namely a section through a cutting and repitching device, and

[0045] FIG. 3 is a top view of a stretching device with rotating disks for stretching a material web. In this purely schematic example, the unstretched web enters from the right and exits stretched on the left, being stretched from width B to width B'.

[0046] Identical or equivalent elements are provided with the same reference numerals in both figures.

[0047] The system 2 shown in FIG. 1 in a longitudinal section and the process implemented thereby serve for the permanent application, in particular by gluing, adhering, or laminating, of a stretched elastic, preferably flat material strip 4 to a carrier material 6 (see also FIG. 2). In particular, the material strip 4 can be designed to form a feces pocket ("poo pocket") or a feces retainer, for example, on the upper, hip-side edge of a diaper, in particular a baby diaper, or an incontinence product. During the process, the material strip 4 is applied in the stretched state to the carrier material 6 and permanently bonded (glued or adhered) to it.

[0048] The elastic starting material for forming the respective material strip 4 is provided in the form of a material web 8 on a supply roll (not shown) and unwound from this. In the example in FIG. 1, the material web 8 is fed from the top left against the machine direction 10 (for the definition see below) to the right of the system 2, then initially runs past a deflection roller 12 and subsequently runs through a roller combination with a driven feed roller 14, which ensures the feed of the material web 8 under appropriate material tension. The material web 8 then runs in a zigzag manner through a dancer device 16, which acts as a temporary material store and for tension control of the material web 8 for the subsequent system sections. Downstream of this, a web control unit 18 and, if necessary, a further feed roller, through which the material web 8 passes, can be provided.The web control unit 18 aligns the position of the material web 8 transversely to the machine direction 10 and thus centers the material web 8 (so-called web edge control or regulation). The details of the web feed described above can vary in many ways; this is not relevant here.

[0049] The material web 8 is then fed via a number of deflection rollers 20 to a stretching device 22, which stretches the elastic material as it passes transversely to the machine direction 10 (i.e., in the transverse direction, here perpendicular to the plane of the drawing) and is therefore also called a transverse stretching device. The stretching device 22 can, in principle, have the design and the corresponding functional principle known from EP 0672516 A2. This means that the stretching device 22 comprises two spaced-apart, slightly divergent (not exactly parallel) aligned discs 24, which each grip the incoming material web 8 at the edge, transport it approximately half a turn (or slightly less in other designs), and thereby stretch it in the transverse direction due to their divergent alignment.The discs 24 therefore preferably serve as transport discs and, at the same time, as expansion elements, which move away from each other transversely along their outer circumference during half a rotation (and then approach each other again). For this purpose, the discs 24 are mounted on rotation axes 26, which are slightly inclined relative to each other compared to a parallel configuration of the discs 26. The pair of two discs 24 is also referred to as a disc pair for short.

[0050] Preferably, the discs 24 are adjustable with regard to their inclination (ie with regard to the angle between their axes of rotation 26) in order to be able to adjust the degree of stretching of the material web 8.

[0051] In the example, the rotation axes 26 of the disks 24 are both perpendicular to the machine direction 10 and symmetrically inclined slightly to the horizontal, so that the two disks 24 are closest to each other at the uppermost point of their outer circumference and farthest apart at the lower point. The material web 8, coming from the deflection roller 20 (here in the machine direction 10), enters the stretch device 22 tangentially to the pair of disks at its highest point and exits again at the lowest point tangentially to the pair of disks at their lowest point (here opposite the machine direction 10). This results in a 180° anti-clockwise deflection of the material web 8. The closest distance between the pair of disks at the inlet 28 corresponds to the width of the unstretched material web 8 entering the stretch device 22, and the greatest distance at the outlet 30 corresponds to the width of the stretched material web 8 exiting.

[0052] To securely hold the material web 8 during transport and stretching, the two discs 24 of the stretching device 22 are expediently provided with radially directed suction holes arranged on their outer circumference, which are supplied with negative pressure ("vacuum") during operation. This suctions the material web 8 along its edges and holds it securely. This can be supported by retaining hooks, coatings that promote static friction, and / or non-slip profiles on / at the running surfaces of the discs 24. In a preferred embodiment, the vacuum supply, i.e., the air suction, is guided through the shaft of the respective disc 24, which opens up the possibility of preventing air suction during empty travel (when no material is in contact with the suction holes) by means of suitable flow guidance. However, this can also be achieved by alternative designs, for example by means of laterally mounted suction cups.

[0053] In a preferred embodiment, the pair of discs of the stretching device 22 can be driven at a suitable rotational speed that is matched to and synchronized with the propulsion of the material web 8 or, alternatively, can rotate passively with the material web 8.

[0054] At the outlet 30 of the stretching device 22, the transversely stretched material web 8 is transferred to a horizontally oriented (vacuum) conveyor belt 32 running counter to the machine direction 10. The stretched material web 8 is transported further in this stretched state through the suction holes integrated into the conveyor belt 32, which are supplied with negative pressure during operation.

[0055] During further transport, the material web 8 is guided past a gluing device 34. The gluing device 34 has a glue application head 36 which extends in the transverse direction preferably across the entire width (or alternatively across individual sections thereof) of the stretched material web 8, by means of which glue is applied continuously or in pulsed fashion to the upper side of the material web 8, preferably across its entire width or at selected points along its transverse extent, expediently at least in the edge region of the material web 8. This creates a glue application on the upper side of the material web 8 which is continuous in the longitudinal direction of the material web 8 or divided into successive transverse stripes or zones.

[0056] As indicated above, by appropriately designing the glue application head 36, optionally divided into individual sub-heads, any desired glue pattern can be applied in the transverse direction of the material web 8 (i.e., in the longitudinal direction of the subsequent material strip 4). For example, strong fixation at the outer edges and light fixation in the center is possible, which can save glue. Alternatively, a dotted or dash-dotted glue line is possible, or any desired variations thereof. To create a pocket on / in a hygiene product, a U-shaped bond (as viewed from above) is particularly preferred. The opening of the U must point towards the center of the absorbent body of the hygiene product. For this purpose, the glue application head can include an application template with the desired outline. Such measures can also influence the ruffling of the product.

[0057] Glue is understood here to mean any adhesive material that flows or sprays during application and that, after pressing, curing, drying, or undergoing a structural change over time (after prior activation), leads to a permanent bond between material strips 4 cut from the material web 8 and the carrier material 6. In this respect, any suitable glue, adhesive, adhesive substance, etc. is included. For the sake of simplicity, where only "glue" is referred to in some places in the text, the aforementioned forms and alternatives are always included. The use of thermoplastic hot melt adhesives is particularly preferred in this context. Ultimately, however, this depends on the materials to be joined and may vary for different applications.

[0058] The conveyor belt 32, conceptually described in the preceding sections as "one" belt, with which the material web 8 is transported in the stretched state from the stretching device 22 past the glue application head 36 to the cutting and repitching device 38, can, on closer inspection as can be seen from FIG. 1, be seen or composed of two separate conveyor belts, namely a first circulating conveyor belt 32-1 from the stretching device 22 to just before the glue application head 36, and a second circulating conveyor belt 32-2 from just behind the glue application head 36 to the cutting and repitching device 38. In the area of ​​the glue application head 36 there is a gap between the two belts, which is easily bridged by the material web 8.This prevents the conveyor belt 32 from being accidentally sprayed with glue, for example, if the material web 8 is not properly centered, is missing, or has gaps or recesses. A collecting tray 80 (preferably coated with an anti-adhesive coating) arranged in the gap between the belts, below the material web 8, advantageously catches any dripping glue in such cases. Furthermore, with the collecting tray 80 removed and the material web 8 missing, the glue application head 36 is easily accessible from below through the gap between the belts, which can be advantageous for certain maintenance and inspection procedures.

[0059] The glued material web 6 is then transported further on the vacuum conveyor belt 32 against the machine direction 10 and transferred to a cutting and repitching device 38, the essential elements of which are shown enlarged in FIG. 2.

[0060] The cutting and re-pitching device 38 serves to separate the incoming material web 8 into individual transverse strips, namely the desired material strips 4, by cutting them transversely. These strips are then transferred to another conveyor belt 40, on which the carrier material 6 is transported, by adjusting their pitch and changing the direction of movement and orientation. Even during these processes, the material strip 4 remains stretched.

[0061] A central component of the cutting and re-pitching device 38 is a cutting unit 42 on the input side, which comprises a driven cutting roller 44 arranged above the material web 8 with a horizontal rotation axis 46 in the transverse direction, here with a counterclockwise rotation direction. The cutting roller 44 has a number, preferably a plurality, of rotating cutting blades 48 arranged on the outer circumference, which cut the incoming material web 8 by cutting from above across the entire width into individual material strips 4 of the desired width (corresponding to the longitudinal spacing between successive cuts in the web's longitudinal direction). For this purpose, the advance speed of the conveyor belt 32, the number and arrangement of the cutting blades 48, and the rotational speed of the cutting roller 44 are suitably coordinated with one another.

[0062] Furthermore, the cutting and repitching device 38 comprises a repitching unit 50 with a rotating, driven shaft 52 with a horizontal rotation axis 54 in the transverse direction, here with a clockwise rotation direction. The shaft 52 is located at the end of the transport path formed by the conveyor belt 32, below the cutting roller 44.

[0063] A number, preferably a plurality, of transfer heads 56 are arranged on the circumference of the shaft 52, each of which has a flat receiving surface or support surface 58 for a material strip 4 cut from the material web 8 at the radially outward end. The expansion of the material strips 4 is also maintained here by suction holes integrated into the support surface 58, which are subjected to negative pressure during operation. The effect of these suction holes can in turn be supported by special geometries, profiles and / or coatings of the support surface 58 and / or by means of holding hooks, etc. Here, too, it is possible to prevent suction in the idle section (in which no material strip 4 is in contact with the suction holes) of the transfer heads 56 by suitable flow guidance of the intake air, for example through the shaft 52.

[0064] The transmission heads 56, which protrude essentially radially from the shaft 52, basically rotate with the shaft 52, but can be tilted forward in the direction of rotation by an integrated mechanism and thus accelerated in sections relative to the shaft 52 during one rotation or tilted backward and decelerated.

[0065] The arrangement and control of the components, as shown in FIG. 2, is such that the material strip 4 cut from the material web 8 at the end of the conveyor belt 32 is transferred to an associated transfer head 56 (also called a transport shoe) at the moment of separation and is transported further by this in an expanded state around the rotational axis 54 of the shaft 52. The inlet 60 of the material strip 4, located in the tangential direction to the roller, corresponds to the upper position of the transfer head 56, and the outlet 62, with transfer of the material strip 4 to the underlying carrier material 6 (under which, in turn, the conveyor belt 40 is located), corresponds to the lower position of the transfer head 56.

[0066] The respective transfer head 56 is preferably controlled such that it is accelerated during the movement phase between inlet 60 and outlet 62 (here in the example corresponding to a 180° clockwise rotation of the shaft 52) ​​with the material strip 4 in place and decelerated during the subsequent idle phase without the material strip 4. After a full rotation of the shaft 52, the transfer head 56 returns to its starting position. The aforementioned dynamic variation of the circumferential speed adjusts the spacing (repitch) between successive material strips 4, in particular increasing the spacing from zero immediately during cutting to a predetermined value upon transfer to the conveyor belt 40 for the carrier material 6. Ultimately, this results in an adjustment to the transport speed and the spacing of the carrier material 6 on the conveyor belt 40.This ensures that the material strip 4 at the transfer point or handover point has reached the propulsion speed of the carrier material 6 and the desired relative position thereto (synchronization).

[0067] Overall, this results in a reversal of the direction of movement of the material strips 4 from previously opposite to the machine direction 10 to in the machine direction 10, with a change in the distance between successive material strips 4 and a 180° flip of the position of the respective material strip 4 from previously upside down to upright. This means that at the inlet 60 of the repitch unit 50, the side of the material strip 4 with the glue application is on top, and at the outlet 62, it is on the bottom.

[0068] In principle, the cutting unit 42 can be decoupled from the repitch unit 50 in terms of position, i.e., moved forward in the transport path of the material web 8. However, the described combination unit has the advantage that the material web 8 can be guided as a whole to the end of the conveyor belt 32, whereby the material strip 4 severed at the front end by the cutting unit 42 comes to rest directly and correctly positioned on the associated transfer head 56 of the repitch unit 50 at the moment of separation and is then transported further by it. During cutting, the support surface 58 of the transfer head 56 forms a cutting base or counterpressure plate, so that separate counterpressure rollers or counterblades can be dispensed with.

[0069] The horizontally oriented conveyor belt 40, arranged below the conveyor belt 32 for the material web 8 and below the cutting-repitch device 38, serves to transport the carrier material 6 and thereby defines the machine direction 10 as the feed direction of the carrier material 6 (here from right to left) in the system 2. The carrier material 6 can lie on the conveyor belt 40 either in the form of already separated, preferably flat carrier products located at a defined distance from one another, or alternatively in the form of a carrier material web that is only separated or separated into individual carrier products at a later process time. Conveniently, the conveyor belt 40 is a vacuum conveyor belt with integrated suction holes subjected to negative pressure during operation, which reliably hold the carrier material 6 over the entire transport path, in particular during the application of the material strips 4.

[0070] The arrangement and control of the components is such that the respective stretched material strip 4 is placed at the outlet 62 of the cutting-repitch device 38 by the transfer head 56 directly at the desired support position, with the glue application directed downwards toward the carrier material 6, onto the carrier material 6 passing below it, and is preferably lightly pressed down. The height of the shaft 52 is preferably selected such that the material strip 4 comes into contact with the carrier material 6 in the transfer position. For this purpose, the lower conveyor belt 40 is expediently adjusted to the height of the shoes or transfer heads 56. This means that the support surface 58 of the transfer head 56 is located approximately at the level of the upper surface of the conveyor belt 40 in this lower position.As a result, the material strip 4 aligned in the transverse direction of the system 2 is applied in the correct position to the carrier material 6 as seen in the machine direction 10 and is bonded together by means of the glue application.

[0071] In order to support the most immediate possible connection between the material strip 4 and the carrier material 6, the conveyor belt 40 with the carrier material 6 lying on it is pressed briefly (pulse-like) and locally (seen in section) from below against the passing transfer head 56 with the material strip 4 still adhering to it (at this moment) at specific points at the moment of transfer. This is particularly important when using hot melt. For this purpose, a pressing device 64 with a driven roller 68 is arranged below the conveyor belt 40, namely exactly below the transfer position, which rotates about a rotational axis 66 during operation. On the circumference of this pressure device 64 a number, preferably a plurality, of preferably spring-mounted pressure rollers 70 are arranged, which preferably roll passively at the moment of belt contact. This can also be referred to as an eccentrically mounted pressure roller 70.The rotation of the roller 68 of the pressing device 64 is synchronized with the rotation of the shaft 52 of the repitch unit 50 in such a way that the above-mentioned targeted pressing of material strips 4 and carrier material 6 against each other is realized at the moment of coming into contact.

[0072] Further downstream in the process, here further to the left in the transport path of the conveyor belt 40, a second pressing device 72 of the type described can be provided below the conveyor belt 40 to further support or intensify the firm or permanent connection of the material strip 4 and the carrier material 6 by a second pressing action. Instead of the shaft 52 of the repitch unit 50 with the transfer heads 56, a simple counterpressure roller 72 is arranged above the conveyor belt 40.

[0073] If the carrier material 6 runs onto the conveyor belt 40 as a carrier material web, a cutting or separating device for separating the carrier material web with the applied material strips 4 into individual carrier products can be provided after the cutting and repitching device 38.

[0074] As a result, the system 2 described above first stretches a material web 8 made of an elastic material in the transverse direction, then applies glue while stretched, and then cuts it into individual material strips 4 by cutting in the transverse direction while maintaining the stretch. The typically narrow material strips 4 are transported onward such that their longitudinal direction remains aligned in the transverse direction of the system 2. The material strips 4, still in the stretched state, are laid down on a passing carrier material 6 or carrier product with their spacing adjusted, specifically with the glue applied towards the carrier material 6. This means that the elastic material strip 4 with the glue applied is applied to the carrier material 6 in the stretched state and glued or adhered to it.A glue pattern set on the glue application head 36 is thus not distorted (stretched or compressed) during subsequent process steps, but remains intact until application to the carrier material 6, allowing the locally desired or required amount of glue to be adjusted particularly as needed. By locally pressing the material strip 4 against the carrier material 6 in the application region (i.e., during transfer or contacting), i.e., while the material strip 4 is still stretched, a virtually immediate adhesion of the bonding partners can be supported.

[0075] Overall, proven components are used that work together reliably and reliably. By stretching the entire material web 8 (and not individual material strips 4) before the cutting and re-cutting process steps, problems with folded corners and the like are largely avoided. Furthermore, a particularly simple-to-construct and easy-to-operate stretching device 22, such as a rotary disk stretcher with angled disks, can be used. Suction losses from the vacuum suction system in the overall system can be minimized.

[0076] In the specific application of a “Poo Pocket,” the elastic material web 8 can have an (unstretched) width of, for example, 95 mm. The stretching device 22 increases the width of the material web 8, for example, by 60% or to 150 mm. These are, of course, only exemplary specifications for a very specific concrete application. The width of the stretched material web 8, after separation, corresponds to the length of a stretched material strip 4. The elastic material can be, for example, foam, MDX, or something else. The carrier material 6 or carrier product to which the stretched material strip 4 is applied is preferably a diaper, in particular a modern disposable diaper, throw-away diaper, or diaper pants, in particular with an outer shell made of polyethylene (PE) and an absorbent body, for example made of cellulose material.Alternatively, it is a reusable diaper or a cloth diaper, such as a cotton diaper, or any combination thereof. The glue / adhesive can preferably be a pressure-sensitive hot-melt adhesive, particularly a synthetic, rubber-based, or polyolefin-based type.

[0077] At the end of the production process, when the forced stretching by system 2 is released and the material strip 4 tends to shrink, the applied material strip 4 creates a kind of pocket in the finished product. In the case of a diaper, this is particularly useful in the hip area or at the waistline to retain feces (waistband as overflow protection). This is also referred to as a pocket diaper.

[0078] List of reference symbols

[0079] 2 Appendix

[0080] 4 material strips

[0081] 6 Carrier material

[0082] 8 Material web

[0083] 10 Machine direction

[0084] 12 pulley

[0085] 14 Preferred role

[0086] 16 Dancer device

[0087] 18 Path control unit

[0088] 20 pulley

[0089] 22 Stretching device

[0090] 24 slices

[0091] 26 Rotation axis

[0092] 28 Inlet

[0093] 30 outlet

[0094] 32 conveyor belt

[0095] 32-1 Conveyor belt

[0096] 32-2 Conveyor belt

[0097] 34 Gluing device

[0098] 36 Glue application head

[0099] 38 Cutting and Repitching Device

[0100] 40 conveyor belt

[0101] 42 Cutting unit

[0102] 44 Cutting roller

[0103] 46 Rotation axis

[0104] 48 cutting blades

[0105] 50 Repitch Unit

[0106] 52 Wave

[0107] 54 Rotation axis

[0108] 56 transfer head

[0109] 58 Support surface Inlet Outlet Pressure device Rotation axis Roller Pressure roller Pressure device Counter pressure roller Collecting tray

Claims

Claims 1. A method for applying a stretched elastic material strip (4) to a carrier material (6), comprising the following steps, preferably in the order mentioned: • Stretching an elastic material web (8) in the transverse direction, • optional application of glue / adhesive to at least a partial area of the stretched material web (8), • Dividing the stretched material web (8) into individual stretched material strips (4) by cutting the material web (8) in the transverse direction, • Adjusting the distance between the stretched material strips (4), and • Applying the stretched material strips (4) to a carrier material (6).

2. Method according to claim 1, wherein the carrier material (6) is transported on a first, preferably horizontally oriented conveyor belt (40) during the application of the respective material strip (4), whereby a machine direction (10) and a transverse direction perpendicular thereto are defined.

3. Method according to claim 1 or 2, wherein the stretching of the elastic material web (8) is carried out by a stretching device (22) which comprises two divergently aligned rotating discs (24) which grip the material web (8) at its edges and stretch it in the transverse direction when rotated by a predetermined angle of rotation.

4. Method according to claim 2 or 3, wherein the material web (8) is transferred after stretching to a second, horizontally oriented conveyor belt (32) running counter to the machine direction (10) and is guided past a gluing device (34).

5. The method according to claim 4, wherein the second conveyor belt (32) is located above or below the first conveyor belt (40).

6. Method according to one of the preceding claims, wherein the application of glue / adhesive to the stretched material web (8) is carried out by means of a glue application head (36) which enables a continuous or temporally pulsed application of glue / adhesive over the entire width of the material web (8) or over partial sections thereof.

7. Method according to claim 6, wherein an adjustable glue-adhesive pattern is applied to the material web (8) as seen in the transverse direction.

8. Method according to one of the preceding claims, wherein the cutting of the stretched material web (8) is carried out by a cutting and repitching device (38) which comprises a cutting unit (42) and a repitching unit (50) in immediate proximity to one another.

9. The method according to claim 8, wherein the cutting unit (42) has a driven cutting roller (44) with cutting blades (48) which cut the material web (8) in the transverse direction.

10. The method according to claim 8 or 9, wherein the repitch unit (50) has a rotating shaft (52) with a number of transfer heads (56) which receive the stretched material strips (4) from the cutting unit (42) and transfer them to the carrier material (6) and in the process adjust the distance between the material strips (4).

11. Method according to claim 10, wherein the adjustment of the distance between the stretched material strips (4) is carried out by a targeted variation of the peripheral speed of the transfer heads (56) in the repitch unit.

12. Method according to one of claims 8 to 11, wherein the stretched material strips (4) are deflected by the repitch unit (50) in the machine direction (10) and rotated by 180°, so that when the material strips (4) are applied, the applied glue faces the carrier material (6).

13. Method according to one of the preceding claims, wherein the material strips (4) are applied in the stretched state to the carrier material (6) and thereby glued or adhered thereto.

14. Method according to one of the preceding claims, wherein the respective material strip (4) is pressed against the carrier material (6) by a pressing device (64) during application.

15. The method according to claim 14, wherein the pressing is carried out by a pressure roller (70) mounted eccentrically on a rotating roller (68).

16. Method according to one of the preceding claims, wherein the carrier material (6) is an absorbent hygiene article such as a diaper or can be divided into a number of such hygiene articles by singulation.

17. The method according to claim 16, wherein the material strip (4) forms a pocket, in particular a faeces pocket, on the hygiene article.

18. Appendix (2) for applying a stretched elastic material strip (4) on a carrier material (6) comprising: • a stretching device (22) for stretching an elastic material web (8) in the transverse direction, • optionally a gluing device (34) for applying glue / adhesive to at least a partial area of the stretched material web (8), • a cutting unit (42) for cutting the stretched material web (8) into individual stretched material strips (4), and • a repitch unit (50) for adjusting the distance between the stretched material strips (4) before application to the carrier material (6).

19. Plant (2) according to claim 18, further comprising a conveyor belt (40) for transporting the carrier material (6) during the application of the stretched material strips (4).

20. System (2) according to claim 18 or 19, wherein the stretching device (22) is designed as a rotating disc stretcher with divergingly arranged discs (24).

21. Plant (2) according to one of claims 18 to 20, wherein the cutting unit (42) has a driven cutting roller (44) with cutting blades (48) which cuts the material web (8) in the transverse direction.

22. System (2) according to one of claims 18 to 21, wherein the repitch unit (50) has a rotating shaft (52) with a number of transfer heads (56) which receive the stretched material strips (4) from the cutting unit and transfer them to the carrier material, thereby adjusting the distance between the material strips.

23. Plant (2) according to one of claims 18 to 22, wherein the cutting unit (42) and the repitching unit (50) are arranged in a combined cutting and repitching device (38) in immediate proximity to one another.

24. System (2) according to claim 23, wherein a vacuum conveyor belt (32) for transporting the material web (8) in the stretched state is arranged between the stretching device (22) and the cutting and repitching device (38).

25. Plant (2) according to claim 24, wherein the gluing device (34) is arranged above the vacuum conveyor belt (32).

26. System (2) according to one of claims 18 to 25, wherein the stretching device (22) and / or the repitch unit (50) has an effective angle in the range of 180° ± 30°.

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