Patent ID: 8894808

Claim:
A method for preparing fold lines in laminated materials based on cardboard for producing containers for foodstuff, the laminated materials having an inner layer and an outer layer, wherein the inner layer is formed from at least two plies, the method comprising the step of thermally treating at least one area intended for preparation of a fold line for producing a corner region of the container so that shear fracture stresses of the material are at least partially decreased locally in this area, as a result of which local delamination in this area is supported, wherein, as a result of delamination in the corner region an inner ply of the inner layer of the laminate is partially separated from a neighboring ply of the inner layer in an outer direction of the laminate so that the inner ply of the inner layer extends away from the neighboring ply in the corner region so as to form a hollow space between the inner ply and the neighboring ply.