Production of bags of thermoplastic material - by welding film using wavy line weld in extrusion direction of film

摘要

Package esp. bags are produced from strips of a thermoplastic resin, esp. polyethylene, by welding together the different sides of the package by locally heating/pressing, the strips being welded in the extrusion direction of the film along a wavy line. The wavy line weld is more resistant to undesired tearing-open than a straight line weld. The weld is made after the bag has been filled with a prod., and a handgrip may then be made by cutting the upper unwelded parts. The bag can then be carried without the weld tending to tear-open across the whole width of the bag. If the load on the weld causes a tear at a weekend part, then this tear is localised.