METHOD FOR PRODUCING A GATHERED MATERIAL, AND GATHERED MATERIAL

Abstract

A method for producing a gatherable material comprising the steps of: a) providing two material web sections and a thread in between, b) providing processing device having a tool with a sealing surface and a counter-tool with a counter-sealing surface, the tool and the counter-tool being arranged relative to one another such that a gap is formed in between, the tool and/or the counter-tool having a groove for guiding the thread, c) passing the web sections and the thread through the gap, so that the two material web sections are welded together at two connecting surfaces, the thread being arranged between the two connecting surfaces such that there is a positive connection between the thread and the material web sections, a cross-section of the thread relative to a cross-section of the groove being selected such that an outer section of the thread is also welded to the material web sections.

Claims

1. A method for producing a gathered or gatherable material, the method comprising the following steps: providing at least two material web sections and at least one thread, which is arranged between the material web sections, providing a processing device having a tool with a sealing surface and a counter-tool with a counter-sealing surface, the tool and the counter-tool being arranged relative to one another in such a way that a gap is formed between the sealing surface and the counter-sealing surface, the tool and/or the counter-tool having at least one groove for at least partially receiving the at least one thread, passing the at least two material web sections and the at least one thread through the gap between the sealing surface of the tool and the counter-sealing surface in a feed direction, the thread being guided through the at least one groove of the sealing surface and/or of the counter-tool, so that the two material web sections are welded together at at least two connecting surfaces, the thread being arranged between the two connecting surfaces in such a way that there is a positive connection between the thread and the material web sections in a first and a second direction, the two directions being aligned perpendicular to one another, characterized in that a cross section of the thread relative to a cross section of the groove is selected during processing in such a way that during step c. not only the two material web sections are welded together, but also an outer section of the thread is welded to the material web sections, so that the outer section of the thread is firmly connected to the two material web sections.

2. The method according to claim 1, wherein the grooves for receiving the at least one thread and the cross-section of the thread are selected such that the cross-section of the thread adapts to the groove shape during step c.

3. The method according to claim 1, wherein the cross-section of the thread is selected such that the cross-section of the thread in a tensioned state of the thread is larger than a depth of the groove.

4. The method according to claim 1, wherein the tool is excited with an ultrasonic vibration in step c., so that the two material web sections are processed with ultrasound at the at least two connecting surfaces.

5. The method according to claim 1, wherein the tool is heated in step c. so that the two material web sections fuse together at the at least two connecting surfaces.

6. The method according to claim 1, wherein the groove is oriented in the feed direction, wherein the groove divides the sealing surface and the counter-sealing surface, respectively, into partial sealing surfaces, wherein the groove has a groove base and two side walls adjoining the groove base, and wherein the side walls connect the groove base to the partial sealing surfaces, wherein at least one of the partial sealing surfaces having, in a sectional view perpendicular to the feed direction, at least one flank sloping down towards the groove base, the flank preferably being convexly curved with a radius R.sub.F in a sectional view perpendicular to the feed direction.

7. The method according to claim 6, wherein the groove base is concavely curved, the concavely curved groove base preferably directly adjoining the preferably convexly curved flank of the partial sealing surface.

8. The method according to claim 1, wherein the at least one groove is arranged on the sealing surface of the tool.

9. The method according to claim 1, wherein the sealing surface and/or the counter-sealing surface comprise a plurality of grooves oriented in the feed direction for at least partially receiving the at least one thread.

10. The method according to claim 1, wherein the at least one groove has a depth between 0.05 mm and 0.8 mm.

11. The method according to claim 1, wherein the distance between the at least two connecting surfaces during welding either i) corresponds to the diameter of the thread in a relaxed state or ii) is larger than the diameter of the thread in a relaxed state.

12. The method according to claim 1, wherein the firm connection is made in such a way that, in a sectional view perpendicular to the thread direction, the thread is firmly connected to the material web sections only in sections in the circumferential direction, the firm connection preferably being made in such a way that, in a sectional view perpendicular to the thread direction, the thread is firmly connected to the material web sections in the circumferential direction at two sections separated from one another.

13. A gatherable or gathered material consisting of at least two material web sections and at least one thread which is arranged between the material web sections, the two material web sections being welded to one another at at least two connecting surfaces, the thread being arranged between the two connecting surfaces in such a way that there is a positive connection between the thread and the material web sections in a first and a second direction, the two directions being aligned perpendicular to one another, wherein the thread is firmly connected to the two material web sections.

14. The gatherable or gathered material according to claim 13, wherein it has been produced by a method, the method comprising the following steps: providing at least two material web sections and at least one thread, which is arranged between the material web sections, providing a processing device having a tool with a sealing surface and a counter-tool with a counter-sealing surface, the tool and the counter-tool being arranged relative to one another in such a way that a gap is formed between the sealing surface and the counter-sealing surface, the tool and/or the counter-tool having at least one groove for at least partially receiving the at least one thread, passing the at least two material web sections and the at least one thread through the gap between the sealing surface of the tool and the counter-sealing surface in a feed direction, the thread being guided through the at least one groove of the sealing surface and/or of the counter-tool, so that the two material web sections are welded together at at least two connecting surfaces, the thread being arranged between the two connecting surfaces in such a way that there is a positive connection between the thread and the material web sections in a first and a second direction, the two directions being aligned perpendicular to one another, characterized in that a cross section of the thread relative to a cross section of the groove is selected during processing in such a way that during step c. not only the two material web sections are welded together, but also an outer section of the thread is welded to the material web sections so that the outer section of the thread is firmly connected to the two material web sections.

15. The method according to claim 1, wherein the cross-section of the thread is selected such that the cross-section of the thread in a tensioned state of the thread is larger than a depth of the groove, and wherein the tool is excited with an ultrasonic vibration in step c., so that the two material web sections are processed with ultrasound at the at least two connecting surfaces.

16. The method according to claim 15, wherein the groove is oriented in the feed direction, wherein the groove divides the sealing surface and the counter-sealing surface, respectively, into partial sealing surfaces, wherein the groove has a groove base and two side walls adjoining the groove base, and wherein the side walls connect the groove base to the partial sealing surfaces, wherein at least one of the partial sealing surfaces having, in a sectional view perpendicular to the feed direction, at least one flank sloping down towards the groove base, the flank preferably being convexly curved with a radius R.sub.F in a sectional view perpendicular to the feed direction.

17. The method according to claim 16, wherein the groove base is concavely curved, the concavely curved groove base preferably directly adjoining the preferably convexly curved flank of the partial sealing surface, and wherein the at least one groove is arranged on the sealing surface of the tool.

18. The method according to claim 17, wherein the sealing surface and/or the counter-sealing surface comprise a plurality of grooves oriented in the feed direction for at least partially receiving the at least one thread, and wherein the at least one groove has a depth between 0.05 mm and 0.8 mm.

19. The method according to claim 15, wherein the distance between the at least two connecting surfaces during welding either i) corresponds to the diameter of the thread in a relaxed state or ii) is larger than the diameter of the thread in a relaxed state, and wherein the firm connection is made in such a way that, in a sectional view perpendicular to the thread direction, the thread is firmly connected to the material web sections only in sections in the circumferential direction, the firm connection preferably being made in such a way that, in a sectional view perpendicular to the thread direction, the thread is firmly connected to the material web sections in the circumferential direction at two sections separated from one another.

20. A gatherable or gathered material consisting of at least two material web sections and at least one thread which is arranged between the material web sections, the two material web sections being welded to one another at at least two connecting surfaces, the thread being arranged between the two connecting surfaces in such a way that there is a positive connection between the thread and the material web sections in a first and a second direction, the two directions being aligned perpendicular to one another, wherein the thread is firmly connected to the two material web sections, produced by the method according to claim 19.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Further advantages, features and possible applications will become clear from the following description of an embodiment and the associated figures.

[0052] FIG. 1 shows a sectional view of a section of a tool which is operated using the method according to the invention.

[0053] FIG. 2a schematically shows the arrangement of the thread between the material webs after welding using methods known from the prior art.

[0054] FIG. 2b schematically shows the arrangement of the thread according to one embodiment of the method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0055] According to the embodiment of the device according to the invention shown in FIG. 1, the grooves 3 for receiving the thread 13 are arranged in the sonotrode sealing surface 2 of a sonotrode 1. The grooves 3 run in the feed direction, which extends into the sheet plane in the sectional view shown in FIG. 1. In addition, the grooves 3 divide the sonotrode sealing surface 2 into several partial sealing surfaces 7.

[0056] The grooves 3 have a groove base 4 and two side walls 5, 6 adjoining the groove base, whereby the side walls 5, 6 connect the groove base 4 with the partial sealing surfaces 7.

[0057] In the sectional view shown in FIG. 1, the partial sealing surfaces 7 each have two flanks 8 sloping down towards the groove base 4 perpendicular to the feed direction.

[0058] The sloping flanks 8 are convexly curved with a radius R.sub.F, so that the entire partial sealing surface 7 is convexly curved with a radius RT=R.sub.F. Furthermore, the groove base 4 is also concavely curved with a radius R.sub.G and directly adjoins the convexly curved flanks of the partial sealing surfaces 7. The radius RT of the curved partial sealing surface 7 corresponds to the radius R.sub.G of the concavely curved groove base 4 and is 0.1 mm.

[0059] The grooves also have a width B of 0.22 mm, whereby the width is measured between the two transition points of the concavely curved groove base 4 and the convexly curved flank 8.

[0060] In addition, the grooves 3 have a depth T of 0.21 mm. The depth T of the grooves 3 is defined between the deepest point of the groove base 4 and the highest point of the partial sealing surface 7. The distance A between two grooves is 0.42 mm, whereby the distance A is measured at the deepest point of the groove base 4.

[0061] To produce a gatherable or gathered material 10, two material webs 11, 12 are arranged between the sonotrode sealing surface 2 of the sonotrode 1 and the counter-sealing surface of a counter tool (not shown), between which a thread 13 is arranged. The thread 13 is guided in such a way that it runs inside the grooves 3. Ultrasonic processing of the material web sections 11, 12 only occurs in the area of the partial sealing surfaces 7.

[0062] In methods known from the prior art, a diameter of the thread 13 in a state in which the thread is tensioned is selected so that it is smaller than a depth of the groove 3. This means that the thread 13 is not processed by the sonotrode 1.

[0063] The result of such a process with devices known from the prior art, i.e. with devices whose grooves have sharp edges, is shown in FIG. 2a. The thread 13 is clamped in a cavity between the material web sections 11, 12 of the material 10, but can move in the feed direction relative to the material web sections 11, 12. The lower material web section 12 has the shape of the grooves, which can be arranged on the sonotrode or the counter tool or both.

[0064] According to the method according to the invention, the cross-section of the thread 13 is selected so that it is larger than a depth of the groove 3 even in the tensioned state. The result of the method according to the invention is shown in FIG. 2b. By selecting the larger cross-section of the thread 13, the thread 13 is welded in the area of the partial sealing surface 7. As a result, the thread 13 is also attached to the material web sections 11, 12 and can no longer be moved in the feed direction. The originally circular cross-section of the thread 13 has also adapted to the shape of the groove 3.

[0065] Moreover, in a preferred embodiment, the distance between the at least two connecting surfaces during welding can be selected such that this distance either i) corresponds to the diameter of the thread 13 in a relaxed state or ii) is larger than the diameter of the thread 13 in a relaxed state. Due to the firm connection according to the invention, it is therefore no longer necessary to select a large diameter of the thread 13 in the relaxed state in order to realize friction between material web sections 11 and the thread 13.

[0066] In this way, a gathered or gatherable material can be produced whose threads are always arranged in the same position.

LIST OF REFERENCE SIGNS

[0067] 1 Sonotrode [0068] 2 Sonotrode sealing surface [0069] 3 Groove [0070] 4 Groove base [0071] 5, 6 Side walls [0072] 7 Partial sealing area [0073] 8 Flank [0074] 10 Gathered or gatherable material [0075] 11, 12 Material web sections [0076] 13 Thread