Patent ID: 6913570

Claim:
A method of producing an article comprising a folded core structure, maid method comprising the steps: a) providing a material web having an initial flat planar configuration; b) subjecting said material web having said initial flat planar configuration to a continuous pretreatment process comprising forming a repeating pattern of fold lines in said material web from at least one of an upper surface and a lower surface thereof such that said material web with said repeating pattern of fold lines still has said flat planar configuration; c) after said step b), initiating a formation of folds in said material web along said fold lines on at least one of said upper surface and said lover surface; d) after said step c), carrying out and completing said formation of said folds along said fold lines to deform said material web from said initial flat planar configuration into a three-dimensionally folded configuration having an increased thickness relative to said flat planar configuration, whereby said initial flat planar configuration of said material web undergoes a longitudinal contraction in a longitudinal direction of said material web, a transverse contraction in a transverse direction of said material web, and a thickness expansion in a direction of said thickness; and e) after said step d), post-treating said material web to stabilize maid folded configuration thereof, to produce therefrom a folded core structure.