Collapsible tubular container

35

The invention relates to a packaging tube with a multilayer tube tube having a metallic intermediate layer and thermoplastic cover layers, the upper edge of which engages over the shoulder portion of a tube head made of thermoplastic material independently of this, the shoulder section being covered by an annular disc and a barrier layer extending to the neck of the tube head extends.

A packaging of this kind is known from FR-PS 20 52 074. In this Verpackungstube the upper edge of the tube tube over the full radial extent of the shoulder portion of the tube head is placed inwardly to the neck of the tube head in order to create a barrier against diffusion and radiation, so that also extends the metallic intermediate layer of the tube tube to the neck.

The taper of the tube head cross-upper ends of the tube prepares considerable difficulties in the production, which are the greater, the stronger the reduction in diameter required in each case. In addition, the Tubcnschulter gets due to the self-adjusting wrinkling an unsatisfactory appearance. For this reason, the shoulder portion is covered with a thermoplastic annular disc in the known packaging tube, which must be chosen sufficiently thick to compensate for the existing irregularities on the shoulder surface can.

From US-PS 37 27 022 is a packaging tube f.? from a tube tube having a metallic intermediate layer and thermoplastic cover layers and a tube head made of thermoplastic material which is produced separately therefrom. The tube head can contain a barrier layer which is effective with regard to oxygen and water vapor. According to this US Pat. No. 3,727,022, a metal layer may be attached to the tube head during the induction heating of the tube with the tube head, which consists in particular of a frustum-shaped die cut made of aluminum the exterior of the tail or Tubenkopfes suitably covered.

Apart from the fact that it may result in the tube tube side end of the stamped a the appearance of the tube impairing transition, is particularly disadvantageous that because of the lack of connection of the diecut with the tube no continuous or contiguous barrier layer is present

From CH-PS 4 57 251 it is known to arrange a metallic barrier layer having annular disc in the Schuiterbereich a Verpackungstubc, but it is a generic different packaging tube, in which the tube head is not manufactured separately, but is sprayed onto the tube tube while the tube head material flows between the inwardly bent upper end of the tube tube and the inner boundary of the tube forming in the shoulder region annular disc.

A comparable with the packaging tube known from CH-PS 4 57 251, provided on the inside of the tube head with a metallic barrier layer having annular disc packing tube is known from US-PS 35 65 293. Even with this packaging tube, however, no gap-free, ie continuous, diffusion-preventing barrier layer is achieved from the tube to the neck of the tube head, despite the elaborate manufacturing process.

From DE-AS 17 86 574 a Verpackungstube with a metallic Sperrschid.l having tube tube and a tube head made of thermoplastic material is known, based on the material thickness of the shoulder portion of the tube head approximately centrally in this shoulder part an annular disc is arranged with a barrier layer. Despite the manufacturing effort that must be taken for the purpose of positional positioning of the annular disc, none of the known from this document variants a continuous, any diffusion-preventing barrier layer between the tube tube and neck of the tube head is present.

From DE-OS 21 54 602 a Verpackungstube with e: nem a metallic barrier layer having tube tube and a prefabricated tube head is known, tube tube and Tubcnkopfschulter are connected via an intermediate member which is applied by an injection process and in particular with additives for a striking color is gone. In this intermediate member, at least one element acting as an additional diffusion barrier can be inserted. This element can be a metal ring which, in addition to a decorative effect, also brings about the effect of the additional diffusion screen. This packaging tube is expensive to manufacture and has no continuous barrier between Tubjnrohr and tube neck.

It is the object of the invention to form a packaging tube of the type mentioned in such a way that in the case of up to the Ilals approach continuous blocking

achieved a perfect appearance, ensures a secure connection of the individual components and a rational production is possible.

This object is achieved in that the annular disc has a metallic barrier layer and thermoplastic cover layers that the annular disc engages under an inwardly projecting edge of the tube tube and sits directly on the shoulder part of the tube head and üaß the annular disc with the tube tube and the shoulder part directly over their thermoplastic outer layers is connected

Since the annular disk is arranged as a flat connecting element between the tube head and tube tube and has a metallic barrier layer, a continuous barrier layer results to the neck without is the need to make a strong rejuvenation of the tube rim associated with wrinkling. In addition, a perfect surface is obtained in the shoulder area without additional measures and due to the flat juxtaposition of tube head, washer and tube ensures a secure mutual connection of these parts.

The invention will be explained in more detail below with reference to the drawing; in the drawing shows

Fi g. 1 is a schematic axial sectional view of the head-side portion of a packaging tube according to the invention, and

Fig. 2 is a schematic axial sectional view for explaining an advantageous method for producing e^;ner packaging tube according to FIG. 1.

1 shows a tube tube 2, a connecting body in the form of an annular disc 60 and a tube head 62.

The tube tube 2 is formed by a three-layer composite material, the inner layer 10 and outer layer 6 are preferably made of polyethylene, the middle layer 34 of metal, preferably of aluminum.

The annular disk 60 also consists of a three-layer composite material, namely an outer layer 64 and an inner layer 66 and a barrier layer 68. The layers 64 and 66 are heat-sealing layers, which are preferably made of polyethylene or a copolymer well adhering to the aluminum layer.

The tube head 62 is a molded article made of plastic, such as polyethylene, which is produced in a known manner by injection molding.

The threaded portion of the tube head 62 may have an annular groove 70, whereby a sleeve 72 is formed, which prevents a rapid flow back of the contents immediately after removal. As a result, retightening of harmful air for the product can be avoided as far as possible. Also, the resulting annular groove 70 in this embodiment can be filled by a ring, not shown, made of a material having diffusion-blocking properties.

The tube head 62 further includes a Rinyschulter 74, which serves as a stop and first sealing surface for a screw-on closure cap shown at night. Another cooperating with the cap sealing surface can only be effective if it is elastic. For this purpose, the closure cap can be dimensioned such that it presses with its internal base surface on a ring-shaped sealing lip 76 arranged on the tube head 62. Another possibility for a white sealing surface provides a bevel 78 above the external thread on the tube head 62. This bevel must be adapted to the cap. The sealing lip 76 or the bevel 78 act in conjunction with a plastic cap as elastic seals that can compensate for manufacturing tolerances within certain limits.

The annular disc 60 expands existing in the tube tube 2 barrier layer on the shoulder portion of the tube, whereby such a tube is particularly well suited for sensitive products

The rigidity of the annular disc 60 can be influenced both by changing the wall thickness and by the choice and arrangement of the layers.

The cut edges 90, 92 and 94 shown in Fig. 1 are covered in such a way by overflowing plastic, that it can never come to a direct contact between the contents and the metal and that also on the tube outside no open Schnittkanter, visible.

A particular advantage is remote: that the distance between the barrier layers 34, 68 of the Tubcnrohres 2 and the shoulder portion forming annular disc 60 as small as possible and the overlap of the barrier layers 34, 68 can be kept as large as possible. As a result, the diffusion path is correspondingly large, so that a good diffusion-inhibiting effect is achieved.

Based on the F i g. 2, a method suitable for the production of the packaging tube described in FIG. 1 will be explained.

The practice of this method requires an annular disk 60 having an inductively responsive heat generator layer, such as a metal layer.

As from the F i g. 2, a head portion 80 is placed on a retaining mandrel 82. Subsequently, the annular disk 60 is placed on the head part 80 and the tube tube 2 is brought into a suitable welding position and a constriction 84 is formed. Finally, by means of a pressing tool 86 with a Induk.ionsspule 88 necessary for the connection heat and the associated pressure generated.

These process steps do not necessarily have to be in the order mentioned above. In particular, it is also possible, for example, first to make the connection between the annular disk 60 and the head part 80 or the tube tube 2 and the annular disk 60 separately.

This procedure makes it possible to produce the necessary Schweißwärmc exclusively in the annular disc 60. This can happen when the annular disc contains a much thicker metal layer than the tube tube 2 de by that the frequency required for the inductive heating is tuned to a thicker, located in the annular disc 60 metal layer, so that the metal layer in the tube 2 practically not heated.

Another possibility consists in the concentration of the magnetic fields in the region of the annular disc by a suitable design of the inductor. Finally, by using magnetically conductive, lossless working materials, such as ferrites and powder cores, the concentration of the magnetic field can be significantly enhanced.

It is also possible to arrange the induction source in the mandrel 82 and shield the field in the region of the tube tube 2 if necessary. Since this arrangement offers the possibility that pressing tool 86 made of metal

5 6

The cooling time after the welding process can be considerably shortened.

For this 2 sheets of drawings