Packaging container production method, packaging container production apparatus, and packaging material

A packaging container production apparatus comprising:

• a conveyor presenting a blank support surface for conveying a container blank in a conveyance direction with the one edge of the blank extending transversely of said conveyance direction beyond said blank support surface;
• a folding base presenting an edge support surface, transversely spaced from the blank support surface, for supporting the one edge and presenting a folding edge oriented in said conveyance direction and positioned to be spaced from the one edge of the blank by a distance defining a folding allowance;
• an endless folding belt having a run with a 180° twist pressing against said folding edge with the one edge therebetween, whereby the folding allowance is folded first down and then under the folding base as the container blank is conveyed in the conveyance direction;
• and
• a sealer for sealing the folding allowance against an adjacent portion of the container blank and against an opposing edge of the container blank, thereby forming the blank into a tubular configuration.