Method of Manufacturing a Cartridge

A method of manufacturing a cartridge consisting of a stiff outer container and a deformable inner bag, wherein a first screw conveyor supplies a first thermoplastic plastic material for the outer container and a second screw conveyor supplies a second thermoplastic plastic material for the inner bag to an extruder, which coextrudes a preform, which is arranged between the open halves of a blow mold of a blow molding installation, wherein the blow mold is closed when the preform has the length necessary for the manufacture of the cartridge, wherein formed in the base region of the cartridge to be manufactured there is a pinch seam of material of the outer container, in which the welded base seam of the inner bag is clamped, and wherein the preform is inflated by a pressure medium into engagement with the wall of the blow mold and the cartridge is removed from the blow mold, the method the following steps:

• (a) cutting away the pinch seam to a residual width of 0.6 to 0.15 mm,
• (b) laterally compressing the cartridge and at the same time, rotating the cartridge about its longitudinal axis until the pinch seam bursts open, whereby the welded base seam of the inner bag remains adhered on one side of the burst open pinch seam and the base region of the inner bag on the other side of the inner wall of the outer container is pre-delaminated,
• (c) producing a reduced pressure in the inner bag so that the inner bag collapses at the pre-delaminated side, and
• (d) subsequently completely applying the inner bag to the inner wall of the outer container by an increased pressure.