Device, in particular for closing a top portion of a food container, consisting of a laminate with a peeled and folded-back edge region

A method (400) comprising as method steps (401 to 404)

• a) Provision of a folded planar composite (101) which is a container precursor (102) surrounding an interior (113),
• wherein the folded planar composite (101) comprises a first composite layer (201), a second composite layer (202), a third composite layer (203), a fourth composite layer (204), a first composite region (107) and a further composite region (108);
• wherein the first composite region (107) and the further composite region (108) both belong to a longitudinal seam (111) of the container precursor (102);
• wherein an intermediate region (500) is located between the first composite layer (201) and the second composite layer (202);
• wherein the first composite layer (201) comprises a first carrier layer (205);
• wherein the second composite layer (202) comprises a second carrier layer (208);
• wherein the third composite layer (203) comprises a third carrier layer (209);
• wherein the fourth composite layer (204) comprises a fourth carrier layer (212);
• wherein the first composite region (107) comprises a first layer sequence, comprising as layers superimposing one another in the direction from the intermediate region (500) through the first layer sequence, the second composite layer (202), the third composite layer (203) and the fourth composite layer (204);
• wherein, in the first composite region (107), the third composite layer (203) is joined to the fourth composite layer (204);
• wherein, in the first composite region (107), the first carrier layer (205) or the fourth carrier layer (212) or each of both is characterised by a greater layer thickness than the second carrier layer (208) or the third carrier layer (209) or each of both;
• wherein the further composite region (108) comprises a further layer sequence, comprising as layers superimposing one another in the direction from the intermediate region (500) through the further layer sequence, the second composite layer (202) and the fourth composite layer (204);
• wherein, in the further composite region (108), the second composite layer (202) is joined to the fourth composite layer (204);
• wherein, in the further composite region (108), the second carrier layer (208) is characterised by a greater layer thickness than in the first composite region (107);
• wherein each of the first carrier layer (205), the second carrier layer (208), the third carrier layer (209) and the fourth carrier layer (212) comprises a cardboard which has a residual moisture content in a range from 4 to 15 wt.-%;
• b) Provision of a first fixing element (103), comprising a first fixing surface (105), and a further fixing element (104), comprising a further fixing surface (106);
• wherein the further fixing surface (106) comprises a recess (213);
• wherein the first fixing element (103) is a sonotrode, the further fixing element (104) is an anvil formed to include the recess (213), and the first fixing surface (105) does not include a groove or recess;
• c) Contacting the fourth composite layer (204) with the first fixing surface (105), the first composite layer (201) with the further fixing surface (106), and the first composite layer (201) with the second composite layer (202);
• wherein the first composite region (107) and the further composite region (108) are each at least partially located between the recess (213) and the first fixing surface (105);
• and
• d) Joining the first composite layer (201) to the second composite layer (202);
• wherein in step d), the further fixing surface (106) is formed without a plurality of ribs which are arranged in a region of the recess (213) and a direction of which is not parallel to the longitudinal seam (111).