Device and method for producing a gathered material

A device for producing a gathered or gatherable material, the material consisting of at least two material web sections and at least one thread positioned between the material web sections, the device comprising:

• 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 a processing position in such a way that for producing the gathered or gatherable material in an operation of the device, the material web sections and the thread are guided through a gap formed by the sealing surface and the counter-sealing surface in a feed direction,
• wherein the tool and/or the counter-tool has at least one groove for at least partially receiving the at least one thread,
• wherein the at least one groove is orientated in the feed direction, wherein the at least one groove divides the sealing surface and the counter-sealing surface, respectively, into partial sealing surfaces,
• wherein the at least one groove has a groove base and two side walls adjoining the groove base,
• wherein the side walls connect the groove base to the partial sealing surfaces, and wherein at least one of the partial sealing surfaces has, in a sectional view perpendicular to the feed direction, at least one flank sloping down towards the groove base,
• wherein the at least one flank is part of or all of the side walls,
• wherein each of the partial sealing surfaces in a sectional view perpendicular to the feed direction has one or two flanks sloping down towards the groove base, and
• wherein the one or two flanks is/are convexly curved in a sectional view perpendicular to the feed direction with a radius RF.