Patent ID: 11878840
Assignee: GPI SYSTEMS AB
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A method of forming a paperboard packaging container from a rectangular body blank, the method comprising the steps of:
a) providing a rectangular body blank, the body blank having a longitudinal direction and a transverse direction, the body blank having a first transverse edge and a second transverse edge and a first and a second side edge, an inside surface and an outside surface, the body blank being made from a laminate sheet material comprising a carton substrate layer, the body blank comprising two or more parallel crease lines, the parallel crease lines extending along the second transverse edge between respective first and second line end points, the respective first line end points each being arranged with a distance (d1) of from 2 mm to 15 mm from the first side edge and the respective second line end points each being arranged with a distance (d2) of from 2 mm to 15 mm from the second side edge;
b) forming a tubular container body from the rectangular body blank, the container body having a first end with a first body opening and a second end with a second body opening and a container body wall extending in a height direction of the packaging container between the first body opening and the second body opening, the height direction of the packaging container corresponding to the longitudinal direction of the body blank, the container body wall having an inner surface and an outer surface, a first end edge and a second end edge;
c) sealing together the first and the second side edge in a but-to-but seal using a sealing strip having a sealing strip width, the sealing strip extending over a non-creased area bridging the first and the second side edge and extending between the first and second end points of the two or more parallel continuous crease lines, as seen in a circumferential direction of the paperboard packaging container corresponding to the transverse direction for the body blank;
d) presenting the tubular container body to a crease line forming station and providing the non-creased area bridging over the sealing strip and extending between the respective first and second end points with two or more bridging crease lines such a that a bridging crease line area is formed, extending in the circumferential direction;
e) closing the second body opening by pressing a paperboard disc into the second body opening, the paperboard disc having a peripheral flange being flexed towards the second end in the height direction of the paperboard packaging container and sealing the peripheral flange of the paperboard disc to the inner surface of the container wall;
f) forming a curled second edge by curling the second end of the container body wall inwardly, at the two or more parallel crease lines and at the crease line area, the curled second edge comprising an edge portion and an inner portion;
g) filling the packaging container with bulk solids;
h) closing the first body opening;
i) wherein steps h) and subsequently step g) could alternatively come after step d).