Method for manufacturing tube of packaging tube, involves arranging edge portions relative to each other, such that outer longitudinal gap is formed between main edge portion and external peripheral surface

摘要

The method involves extending a tapered main edge portion along the extending direction of film substrate (2). The main and auxiliary edge portions are arranged opposite to each other to form tube shaped portion and are welded under thermal effect. The edge portions are arranged relative to each other before welding main edge portion on external peripheral surface along circumferential direction, such that an outer longitudinal gap is formed between main edge portion and external peripheral surface. An independent claim is included for a packaging tube.