Thin wall package for use within a reusable cartridge

#This application is a US national stage application of PCT Application PCT/EP99/07558, filed Oct. 10, 1999, claiming priority to European Application EP 988 11 014.4, filed Oct. 8, 1998.

#The use of two component cartridge systems is well known for the storage, metering and mixing of two component reactive chemical systems such as epoxies, polyurethanes, acrylics, silicones, polysulfides and polyesters. It is also well known that, for environmental reasons, cartridge systems including sausage type packages with thin plastic/foil laminate membrane walls are used to contain such chemicals. These packages are fitted within and supported by a cartridge like structure while the contents are dispensed. When depleted, the sausage type packages may be disposed of, while the whole (or majority) of the supporting cartridge structure can be reused.

#It is within this field of sausage type package use that certain problems are seen to arise. For example, U.S. Pat. Nos. 5,332,122 and 5,501,368 teach containers for flowable substances. These containers require packages fabricated from flexible plastic foil/laminate sheets. For a given package, the flexible plastic foil/laminate sheet is folded to form a tube and then partially overlapped and welded together such that, along the weld length, the now double layer seam is thicker and less flexible than the rest of the package wall and is subject to potential leakage due to weld failure. Moreover, the aforementioned container tube fabrication takes place as the first stage of a complex and continuous fabrication, filling and closing process, the process continues after the initial closing of the tube with the immediate chemical filling of the tube as the second stage. The third stage involves the dividing off and closing of the, now, filled tube into volumetrically controlled lengths. At the division points, the filled tube diameter is reduced all the way to the tube axis, which results in considerable wrinkling of the tube wall prior to being closed by a crimped ring. Such crimped ring closures often fail to achieve an effective seal due to the incompressibility of the membrane and of the wrinkled overlaps which, themselves, tend to form leak paths under pressure. For the same reasons, the necessary sealing of the wrinkled tube wall against a front outlet is another failure area.

#Preferred embodiments of the invention will now be described in detail by reference to the accompanying drawing. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

#FIG. 1 shows a longitudinal cross-section of a package according to a first embodiment of the invention;

#FIG. 2 shows a longitudinal cross-section of a package according to a second embodiment of the invention;

#FIG. 1 shows a longitudinal cross-section of a bottle shaped package assembly 1 having an integrally formed and seamless thin flexible wall 2 with an open neck end 3 passing through the inside of the tube 4 of a front outlet 5, the flexible wall 2 being folded back over the front outside diameter of that tube 4. A sealing ring 6, with lips 7 and 8 for sealing against the cartridge outlet, is fitted over the flexible wall 2 on the inside and outside of the tube 4, the sealing ring 6 being formed to receive a separate sealing plug 9.

#It follows from the above that the package is made bottle shaped so as to essentially match the internal shape of a supporting structure before its insertion, such that it minimizes the necessary adjustment of the external shape of the package to that of the supporting structure which could otherwise lead to air induction into the package when the package is inserted inside the supporting structure and opened prior to dispensing. Furthermore, in comparison with the “state of the art” package which has two closed off ends, this aspect of the invention proposes a package assembly with only one closable open neck end, the open neck end having a reduced diameter with the advantage of the entire package wall having no wrinkles whatsoever.

#Another aspect of the invention for a fabricated sausage type package according to FIG. 2, proposes the use of a compressible plug, rod or mushroom like device held within the closed wrinkled wall end such that the closure means, for instance a crimped ring, creates and maintains a compressive tension, the compressible device itself acting as an expanding and self adjusting sealing bung.