| abstract |
A flexible, collapsible container having walls essentially 0.01 to 0.03 inch thick and defining relatively thin lines of folding weakness in the container to facilitate flat collapse. The thickness of the lines of folding weakness is less than that of the surrounding walls. The cross-sections of the lines of folding weakness define arcs, the outer surfaces of which have a circumferential length which is 40 to 60 percent greater than the direct width of the lines of folding weakness. Preferably, the container is made of a relatively stiff polyolefin plastic such as polyethylene, polypropylene, or copolymers thereof of similar stiffness, particularly biaxially oriented materials. |