Method for producing a cartridge consisting of a rigid outer container and a deformable inner bag

Abstract

The procedure is characterized by the following steps: a) the pinch weld is cut to a residual width of 0.6 to 0.15 mm, preferably 0.2 mm, b) the cartridge is compressed laterally and rotated around its longitudinal axis until the pinch seal bursts open, whereby the welded bottom seam of the inner bag remains adhered to one side of the burst pinch seal, and the bottom area of ​​the inner bag is slightly pre-delaminated on the other side of the inner wall of the outer container, c) a negative pressure is created in the inner bag so that the inner bag collapses on the pre-delaminated side, d) the inner bag is then completely pressed back against the inner wall of the outer container by applying overpressure.

Description

[0001] The invention relates to a method for producing a cartridge consisting of a rigid outer container and a deformable inner bag. In this method, a first screw conveyor feeds a first thermoplastic material for the outer container and a second screw conveyor feeds a second thermoplastic material for the inner bag to an extruder, which co-extrudes a preform that is placed between the open halves of a blow mold of a blow molding system. The two plastics do not form a welded bond. The blow mold is closed when the preform has reached the length required to produce the cartridge, creating a pinch seam in the base region of the cartridge to be produced. This pinch seam consists of the material of the outer container on the outside, into which the welded bottom seam of the inner bag is clamped.The preform is then inflated by a pressure medium to contact the wall of the blow mold, whereupon the cartridge is removed from the blow mold.

[0002] Such a method is known, among other things, from US 2007 / 0040306 A1 and is practiced in numerous variations. Until now, it has always involved detaching the inner bag from the wall of the outer container before filling it with the liquid or pasty filling material to be dispensed, and then reattaching it to the outer container. This detachment of the inner bag, which initially adheres to the inner wall of the outer container by adhesion, is necessary so that the inner bag can contract when the container contents are dispensed. In the methods of this type encountered to date, the inner bag is completely detached or delaminated from the inner wall of the outer container so that the entire contents can be dispensed.

[0003] The present invention is based on the object of providing a method for producing a cartridge suitable for use in a nebulizer. In this application, the cartridge contains a fluid to be nebulized, which has a pharmaceutical composition and / or is a liquid medicament. When used in a nebulizer, a predetermined number of sprays are dispensed from the cartridge. Unlike in known applications, the cartridge is not intended to be completely emptied.

[0004] This object of producing a cartridge suitable for use in an atomizer of the above-mentioned type is achieved according to the invention by the steps characterized in claim 1.

[0005] Advantageous further developments of the method are characterized in subclaims 2 to 8.

[0006] The invention provides that after the cartridge is removed from the blow mold and cooled, preferably to room temperature, the pinch seam is cut to a remaining width of 0.6 to 0.15, preferably 0.2 mm. The pinch seam is cut in a cutting system with a flat and even cut so that preferably approximately 0.2 mm of the pinch seam remains. This ensures that a sufficient pinch area remains on the inner bag to ensure its tightness at the bottom.

[0007] The cartridge is then compressed sideways and rotated around its longitudinal axis until the pinch seam opens or bursts open, with the welded bottom seam of the inner bag remaining stuck to one side of the burst pinch seam, i.e. the welded bottom seam of the inner bag remains stuck to one half of the pinch seam. At the same time, the bottom area of ​​the inner bag on the other side is slightly pre-delaminated from the inner wall of the outer container, i.e. it is slightly detached, while the inner bag continues to adhere to the inner wall of the outer container on the side to which the welded bottom seam remains stuck in the burst pinch seam. This ensures that the inner bag is not turned upwards as the container contents are increasingly dispensed during use, as the inner bag is fixed to one half of the pinch seam.This detachment of one half of the inner bag takes place in a preferred embodiment of the method in that the cartridge runs upright on a circulating horizontal conveyor belt between a vertical circulating belt around a fixed belt, wherein one of the two belts in the lower region of the cartridge has a projecting contour, the distance of which from the oppositely arranged belt is slightly smaller than the outer diameter of the cartridge, wherein the cartridge is rotated about its vertical axis and is compressed in the lower region in such a way that the pinch seam bursts open.

[0008] The open pinch seam allows pressure equalization between the inner bag and the outer container when the container contents are released.

[0009] Because the cartridge is rotated over a specific distance, preferably at least one full revolution, pre-delamination does not occur suddenly, which could cause the inner bag to tear, but rather gradually. During rotation, the cartridge runs along a protruding contour, which is preferably formed on the stationary band. This contour can change in height and protrusion over the squeeze distance. As the cartridge rotates, the inner bag progressively detaches on one side of the burst pinch seam. At the end of this process, one half of the inner bag is pre-delaminated, at least in the base area.

[0010] The cartridge is then preferably transferred to a collapsing station, where a mandrel is inserted into the cartridge and a cylinder evacuates the trapped air inside, creating a negative pressure that can be measured inside the cartridge. At a certain negative pressure level, the pre-delaminated half of the inner bag completely separates from the corresponding inner wall of the outer container.

[0011] A switching valve then creates overpressure in the cartridge, allowing the inner bag to fully adhere to the inner wall of the outer container. The cartridge is then ready for use in an atomizer.

[0012] The detachment of the pre-delaminated inner bag half is carried out using a slight negative pressure so that the welded bottom seam of the inner bag remains stuck in the burst pinch seam.

[0013] When using the cartridge in an atomizer, not the entire contents of the cartridge are dispensed, but after a predetermined number of sprays, a residual amount remains in the cartridge, which is discarded.

[0014] The method according to the invention advantageously provides for the cartridge to be inflated in such a way that the base region of the cylindrical cartridge is rounded, tapering in an arcuate manner – and symmetrically – toward the pinch weld on two opposite sides. The height of the rounded base region of the cartridge is preferably 5% to 10% of its total height.

[0015] In further detail, it is advantageously provided that the cartridge is compressed in the lower third of its height. The circulating belt should run at the same speed as the horizontal conveyor belt, and it is advantageous that both of these belts be made of fabric or rubber. The stationary vertical belt, on the other hand, is advantageously made of an aluminum alloy or steel.

[0016] The two belts run at such a speed that the cartridge on the vertical belt rotates at least once through 360°, although several rotations through 360° may also be appropriate.

[0017] As already mentioned at the beginning, the cartridge is ideally suited to be inserted into an atomizer, preferably filled with a pharmaceutical composition and / or a liquid medication.

[0018] Further details of the invention will become apparent from the following description and the drawings, which show: Fig. 1A is a perspective view of a preferred embodiment of the cartridge and Fig. 1B a vertical section through the pinch edge of the cartridge.

[0019] The cartridge has a circular cylindrical shape with a rounded base, which tapers towards the pinch seal on two opposite sides in an arc. The cartridge consists of a stable outer layer, preferably made of PP, and a highly adhesive, flexible inner layer, preferably made of LDPE. The rounded base allows the inner bag to be gently detached from the outer container, allowing the inner bag to collapse in the lower millibar range, i.e., to contract, without the inner bag detaching from the pinch seal and bulging upwards during detachment.

[0020] In a preferred embodiment, the cartridge has the following data. - Bottle total height (including non-separated pinch weld): 44.7 + / -0.5 mm - Bottle height (with separated pinch seam): approx. 43.10 mm - Pinch weld height: approx. 2 mm and after cutting approx. 0.4 + / -0.2 mm - Cartridge diameter: 15.6 + / - 0.15 mm - Cartridge filling volume: 5.07 + / - 0.2 ml - Cartridge weight: 1.80 + / - 0.1 g - Material outer layer: PP - Product contact layer: LDPE - Collapse range with filled medium: 26 mbar + / - 8 mbar

Claims

[1] A method for producing a cartridge consisting of a rigid outer container and a deformable inner bag, wherein a first screw conveyor feeds a first thermoplastic material for the outer container and a second screw conveyor feeds a second thermoplastic material for the inner bag to an extruder which co-extrudes a preform which is arranged between the open halves of a blow mold of a blow molding system, wherein the blow mold is closed when the preform has the length required to produce the cartridge, wherein in the bottom region of the cartridge to be produced a pinch seam is formed from material of the outer container, in which the welded bottom seam of the inner bag is clamped, and wherein the preform is inflated by a pressure medium to bear against the wall of the blow mold and the cartridge is removed from the blow mold, characterized by following steps: a) the pinch weld is cut to a residual width of 0.6 to 0.15 mm, preferably 0.2 mm, b) the cartridge is compressed laterally and rotated around its longitudinal axis until the pinch seal bursts open, whereby the welded bottom seam of the inner bag remains adhered to one side of the burst pinch seal, and the bottom area of ​​the inner bag is slightly pre-delaminated on the other side of the inner wall of the outer container, c) a negative pressure is created in the inner bag so that the inner bag collapses on the pre-delaminated side, d) the inner bag is then completely pressed back against the inner wall of the outer container by applying overpressure. [2] Method according to claim 1, characterized by that the cartridge is inflated in such a way that the bottom area of ​​the cylindrical cartridge is rounded by running in an arc shape towards the pinch weld on two opposite sides. [3] Method according to one of claims 1 to 2, characterized by , that in step b) the cartridge runs upright on a revolving horizontal conveyor belt between a vertical revolving belt and a stationary belt, one of the two belts having a projecting contour in the lower region, the distance of which from the oppositely arranged belt is slightly smaller than the outer diameter of the cartridge, that the cartridge rotates around its vertical axis as it passes between the belts and that the cartridge is compressed in the lower area in such a way that the pinch seam bursts open. [4] Method according to claim 3, characterized by that the fixed band has the projecting contour. [5] Method according to one of claims 1 to 4, characterized by that the cartridge is compressed in the lower third of its height. [6] Method according to claim 3, characterized bythat the circulating belt runs at the same speed as the horizontal conveyor belt. [7] Method according to one of claims 3 to 6 characterized by that the belts run at such a speed that the cartridge on the vertical belt rotates at least once through 360°. [8] Method according to one of claims 1 to 7 characterized by that the cartridge is inserted into an atomizer.

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