Improvements on multi-ply paperbags, comprising an airtight film or equivalent, which is interposed between two paper layers

摘要

The bag has a polyethylene film (4) impermeable to air and interposed between two paper folds (2, 3). The film is folded to form a sleeve with two contactless edges spaced by an interval (5) for permitting free passage of the air for deaeration, during filling of the bag. The fold (2) has a band (6) impermeable to air to impose a path to the air such that air penetrates between the fold and the film, and evacuates towards outside.