Double-layered, lid-shaped stamped closing element

The present invention relates to a lid-shaped punched- Element for closing containers consisting of two layers with at least one integrated within these layers opening aid, wherein the direction of the container arranged in a position with perforations or predetermined breaking points provided plastic layer. The invention further relates to a method for producing this two-layer closure element.

It is known, for example, microwave containers with two-ply to close the shutter members, wherein the outer layer has a facing paper or metal layer and the second container Location is a plastic layer. Since the materials of the outer layer oppose the passage of the microwaves, it must before Heating the container to be removed. The now with the plastic film closed containers must subsequently perforated by hand are to the escape of steam during warm-up or cooking of the content allow.

According to the European patent no. 457 629 is a two-layer closure element described for microwave container, which has a Metal layer and further a direction of the container rim arranged having heat reactivatable plastic layer. When closing of the container by heat sealing takes place in the area of Seal a crosslinking reaction within the warmreaktivierbaren Plastic layer, a so by forming the seal seam airtight closure of the container is possible. This heat reactivatable Plastic layer can further comprise perforations, so that the formation of an overpressure in the container during the warming or cooking of the content is prevented by microwaves.

The according to the European Pat. No. 457 629 described two-layer Fastener elements are produced by coextrusion of warmreaktivierbaren Plastic layer to a metallic layer as the outer layer in the form manufactured by Rolls. These rolls will be for the packing process, which takes place continuously used. punching However, it is not possible in the form of individual closure elements, as the composite produced by coextrusion in a loose arrangement exists, so when handling occurs shifting of the layers.

The invention aims to remedy this.

According to the invention a two-layer closure element of the initially suggested mentioned kind which is characterized in that the layers of the closure element by means of a peelable are glued to the adhesive layer, and that the opening aid and the the plastic layer containing layer in the region of the perforations or predetermined breaking points are free of adhesive.

Alternate embodiments of the two-layer closure element of the invention are disclosed under the sub-claims.

The invention further relates to a process for the preparation of Closure element of the invention, being the first in a Process step, the layers of the closure element in the form of a manufactures and preliminary assembly of the having the plastic layer Location perforations or predetermined breaking points attaching that one then by cold laminating the layers of the closure element glued together, but the area of ​​the perforations or predetermined breaking points where the plastic layer having Location and the area of ​​the opening aid remain free of adhesive.

Further embodiments of the inventive method according to Subclaims disclosed.

The invention will in the following with reference to a possible embodiment the invention and with reference to a possible process variant closer to the production of the closure element according to the invention explained. These possible embodiments are based on the Sketches shown in FIG representations 1 to 3, in which FIG. 1 a possible embodiment of the two-layer according to the invention Shutter member, Fig. 2 shows a possible method for implementing Preparation of the closure element of the invention and Fig. 3 a container with a closure element according to the invention is closed, show.

In the production of the closure element 1 of the invention the individual layers 2 and 3 are prepared in the form of a pre-laminate.

For the production of the container facing away from sheet 2, for example, an aluminum foil having a thickness in a range of 10 to 100 mm is used. However, it is also possible, plastic film be used in a thickness range of 10 to 100 mm. The Plastics can be chosen from the group of polypropylene, polyethylene, Polyester, polyacrylate, polyamide or polystyrene are selected.

This metal or plastic foil 7 can now be at their the Viewers equipped facing surface side with a printed image will. This may in its surface configuration be both smooth and rough. The surface roughness results by irregular, but also regular arrangement of the print motifs the desired print image. Furthermore, the surface roughness facilitates unstacking the usually superimposed in magazines stored closure elements.

On the opposite side to the print image, the film is 7 exclusively provided with a heat-sealable layer. 8 These can be used as heat seal coating, coextrusion or peelable Plastic film present.

In a further method step, the container is facing Location 3 produced. It is a plastic film 5, for example, a polypropylene film having a thickness of 10 to 100 mm, with a heat-sealable layer 9 laminated. This coating may as well as a heat seal coating, coextrusion or peelable Plastic film are present, wherein the seal seam strength, caused by selection, chemical constitutions and degree of crosslinking Components must be higher than that of the layer. 8 This is because the seal strength produced by the layer 9 airtight to ensure closure of the package or container, while the seal strength produced by the layer 8, cause connection of the layers 2 and 3, but at the same time the "Peeling process" that allow the separation of the plies should.

After laminating the heat-sealable layer 9 are at the Surface of the plastic 5 perforations or predetermined breaking points 6 attached. By superficial scratching of the plastic film for example slot-shaped perforations by needles however punctiform predetermined breaking points are produced.

To the storage of the finished closure elements of the invention 1, which is usually carried out in a batch, to facilitate the heat sealable layer 9, which at the plastic film 5 aufkasc is hiert, advantageously in the form of a rough surface imprint 10 applied. This is done, as shown in shown Fig. 1b, for example by adding additives, such as Silicon particles. Through the generated surface roughness is the Unstacking when using the closure elements of the invention 1 substantially facilitated. This is why, as between included the superficially attached "deformations" air is, and therefore, the individual fastener elements during unstacking facilitate mutual be removed. This process can be additionally improved by the fact that - as shown in Figure 1c. - The rough surface printing of heat-sealable layer 9 in the form is provided by spacers 11th close These spacers, due to their geometric arrangement, in as regularly arranged air gaps a, so that the unstacking is additionally facilitated. This is particularly necessary if, as in the case of food, the packaging, the Container must be quickly closed.

Furthermore, it is possible to on the position facing away from the container 2 applied imprint in the aforementioned rough surface refinement applied so that in addition this measure also or alone causes the stacking properties or additional support becomes.

The present as a pre-composite layers 2 and 3 of the invention Closing element are now in a cold lamination, as shown in Fig. 2, bonded together. It is in a Reservoir 12 to the adhesive 4, for example a polyurethane glue, drawn by means of an applicator roll 13 from the container, at the same time using the sizing roll 14, the order volume can be controlled. Also, instead of polyurethane an acrylic acid ester containing dispersion used will. These obtainable under the name Flex Bond ® dispersion is free from plasticizers and therefore particularly suitable for packaging suitable food. It is now the pre-bond in the form of the plastic layer containing layer 3 from a supply roll 15 and withdrawn via a deflection roller 16 to the surface of the Applicator roll 13 brought. Because of limited surface structure the applicator roller 13 and a pre-controlled pre-run the preliminary assembly 3 with the aid of control elements, carried out a precise cut of adhesive so that the perforations or Predetermined breaking points 6 in the plastic layer having layer 3 remain free of adhesive.

From the supply roll 17 will now be the compound containing the metal layer Location 2 peeled and by nip rolls 18, 18 'with the Plastic layer and already pressed the adhesive 4 having position. The ranges for the opening aid 20 are designed in such arranged such that they, as well as the perforations or predetermined breaking points 6 remain tack-free. By this Kaltkaschiervorgang the layers 2 and 3 glued together so that the closure element 1 'is produced. Due to the nature of the adhesive 4, for example, a polyurethane adhesive, and the elected Kaltkaschiervorgang is an adhesive bond between the individual layers 2 and 3 of the closure element 1 ensures that also during the subsequent sealing process during packaging, ie when closing containers remains unaltered. This makes it possible that as outlined in Fig 2 - - from the web 1 'in a simple manner. by Punching, the desired closure elements 1 prepared can, without the individual layers 2, 3 in their positioning to be changed. When punching is the well-tacky present Opening aid, such as the grip tab 20, 20 '.

The closure elements of the invention are 1 after punching stored in stacks and can further use, namely the Sealing of food containers, are supplied. there for example microwave container 19, which already Foods are filled continuously with the invention Closure element covered and made airtight by sealing tools closed. Before heating in a microwave oven, as shown in shown Fig. 3, containing the, for example, a metal layer Location 2 touched on the grip bottle 20 and in the direction of arrow with Anreißkraft F₁ by having the plastic layer Location 3 withdrawn. By this peeling process now are the predetermined breaking points or perforations 6 exposed on the plastic layer, whereas the adhesive, as shown in Fig. 3, in the form of a strip-like pattern on the example, a metal layer containing layer 2 remains liable. This is also ensured, that any type of penetration of adhesive through the predetermined breaking points or perforations of the plastic layer is avoided, since this only after removal of total of the metal layer containing layer 2 is heated in a microwave oven. After this Heating can also the plastic layer containing layer 3 by pulling on the grip tab 20 'in the direction of arrow F₂ from Containers 19 are withdrawn, so that the removal of the pack Good is made possible.

In summary it can therefore be stated that according to the invention by the Closure member 1 not only an easier closing food containers, such as microwave containers, allows is because a mutual displacement or shifting of Individual layers is conditionally suppressed by the adhesive layer, but that the peelability of the adhesive of any kind Penetration of adhesive into the food container, therefore by in the Food, is avoided in any case.