Hot pressing hinge grooves into prefabricated laminated sheet - for greater versatility than moulding or stretching hinge zones

摘要

Hinge zones are generated in composite or laminated thermoplastic sheet by hot pressing of 'V' profile grooves into one or both faces of the sheet after its fabrication. Esp. used for defining fold axes in packet blanks made from sandwich section sheet having an (expanded) polystyrene core between polypropylene covers or vice versa. Packs of various sizes and shapes are more readily made by adjusting the relative positions of prefabricated sheet and hot hinge pressure tools than by adapting or interchanging moulds with specific hinge zone constrictions or tools applying longitudinal cold drawing.