Method for manufacturing a paperboard bottle and paperboard bottle

A method for manufacturing a paperboard bottle having a tubular body portion, a shoulder and neck portion having a circular cross-section narrowing from the body portion to a circular mouth, the mouth having a smaller diameter than the body portion, wherein the paperboard bottle is made of a liquid packaging board having thermoplastic polymer coating on both sides, the method comprising steps of:

• a) cutting a piece of planar elongated blank from a liquid packaging board sheet or web, the blank having a first end, a second end, a first longitudinal edge and a second longitudinal edge,
• b) protecting exposed cut raw edge of the first longitudinal edge against absorption of liquid,
• c) securing the first end of the blank to a rotatable mandrel having a rotation axis (x) and an outer shape corresponding to the shape of the bottle to be manufactured,
• d) rotating the mandrel about its rotation axis (x) to wind the blank spirally onto the mandrel, so that the second longitudinal edge overlaps the longitudinal first edge, and
• e) applying heat-sealing energy and pressure, while rotating the mandrel, onto the second longitudinal edge to seal the second longitudinal edge together with the first longitudinal edge to form a hermetically sealed spiral seam and to form a monolithic shape of the bottle, and
• f) removing the mandrel from inside the bottle.