Paper or plastic film sack made from a single material sheet has closure flaps with end gussets which, when folded inwards, form reinforced sealing corners

摘要

The sack (50) comprises a base, two broad sack walls (41), two narrower walls (42) folded onto themselves and a sack opening with a closure (48) comprising two first flaps (21) connected to the broad walls and two second flaps (22) folded centrally onto themselves connected to the narrower walls. The faces of gussets (23,24) at the ends of both first and second flaps lie against each other to form double layer sealing corners (47) which are bonded or welded together. Independent claims are made for: a) a process for producing a paper sack in which an adhesively coated transverse edge (15) of the paper sheet is folded over parallel to the latter edge and overlapped with the opposing edge to form a sack open at both ends, four gusset shaped adhesive applications are made on a longitudinal edge (18) at the sack closure (48) which when the closure flaps (21,22) are folded over onto each other bonds the gussets (23,24) together and forms sealing corners (47); b) a plastic film sack manufacturing process in which a sack open at both ends is produced, four gusset shaped overlaps are created along a longitudinal edge between the sack body and the closure and gusset faces bordered by the edge are welded together to form double layer sealing corners. Preferred Features: A boundary line of the first gusset (23) is formed by the connecting edge (18) of each first flap (21) and each corresponding boundary edge of the second gusset (24) runs at a right angle to the free long edge of each second closure flap. After folding the sack closure the corresponding boundary edges run parallel to the sack opening. The flaps and gussets are bordered either by a common folding edge (25) at 45 deg to the connecting edge or by cut edges starting from the connecting edges.