Rigid cardboard envelope is formed of corrugated card with upper and lower sheets crossing corrugated lengths at right angles

摘要

The envelope (1) consists of corrugated cardboard, and the upper side (2) and lower side (3) lie one upon the other by crossing corrugated lengths. The flat upper and lower sides consist of separate corrugated cardboard sections with corrugated lengths crossing over at right angles, and are rigidly interconnected by adhesive along at least two opposite lying edge strips (6,7). The corrugations in the one-piece blank extend at an angle of preferably 45 deg to the outer edges of the envelope so that when the upper and lower sides of folded over the corrugations cross at right angles.