DE202004010214U1 - Lid for closing food containers - Google Patents

Abstract

cover (1) for closing of food containers with an at least three-layer carrier material (2) which its the container facing side is provided with a sealing layer (5), thereby characterized that the carrier material (2) a symmetrical composite with a core layer of paper (3) and is attached to both sides of these polyester layers (4, 4 ').

Description

The The invention relates to a lid for closing food containers an at least three-layer carrier material, which at its the container facing side is provided with a sealing layer.

It is known to make lids for closing food containers Produce aluminum foils, because on the one hand they are easy to process i.e. punched into lids, and on the other hand after sealing the container the food stored therein is satisfactory before the ingress of Protect air and contaminants. Since the aluminum foils used are sometimes relatively thin, show this has the disadvantage that the aluminum cover is unwanted or intentionally destroyed can be. This is done, for example, by scratching the surface of the Aluminum foil during transport, i.e. unwanted after purchasing the Food containers or intentionally through sabotage. Thereby, through the surface incisions also foreign objects, like nails, entered to after the act of sabotage at the food chains or manufacturers ransoms to be able to blackmail. One has therefore started to to install detection devices on the shopping shelves or at the cash registers, to track these acts of sabotage. Because these detection devices reacting to metal in general is one of the most important things when using aluminum flawless detection of foreign objects in the food possible. The invention seeks to remedy this.

According to the invention proposed a lid of the type mentioned, which thereby is characterized in that the carrier material symmetrical composite with a core layer of paper and on both sides attached to these polyester layers. Advantageous configurations of the lid according to the invention are disclosed according to subclaims.

The invention is described below with reference to 1 and 2 , and explained in more detail using exemplary embodiments. It shows 1 a possible embodiment of the lid according to the invention 1 using an untreated polyester film 4 in the carrier material 2 , whereas according to 2 a chemically and / or physically pretreated polyester film 4 ' is used.

To produce a lid according to the invention 1 how he according to 1 is shown attached to a paper layer 3 , which has a grammage of, for example, 40 g / m ', an adhesive layer on both sides 7 applied. It has been shown that the addition of white pigments in the adhesive layer, that of the printing lacquer layer 6 a special brilliance in the finished print 11 causes. On the adhesive layer 7 is now on the first surface of the paper layer 3 a polyester layer 4 , preferably made of polyethylene terephthalate, laminated on and pressed against it. This pre-composite is then stored for about 48 hours to pre-crosslink the adhesive 7 to achieve. In a further lamination step, the second surface of the paper layer 3 another layer of glue 7 applied and to this also a polyester layer 4 attached by cold pressing. For the production of the carrier material 2 in the form of the composite, it is stored for at least one week at room temperature in order to completely crosslink the composite in the form of the carrier material 2 to achieve.

In order to avoid the bowl known from plastics, ie their shape change due to internal stresses, the composite is in the form of the carrier material 2 penetrated plastic films during storage. These creases are avoided by applying pressure to the stretch film. Furthermore, the access to air humidity is prevented by the stretch foils made of plastics.

As a result, the carrier material 2 the printing varnish layer 6 or the sealing layer 5 be applied. For better adhesion, a pre-varnish is used 10 or on the other hand a primer layer 8th applied with application rollers. Then a conventional print is made using pressure rollers 11 generated, which faces the viewer, whereas on the primer layer 8th a sealing layer 9 is applied. By selecting the printing rollers, both on the printing varnish layer 6 as well as on the sealing layer 5 a rough surface pattern can be achieved. The configuration of a surface-rough pattern in the sealing lacquer layer is particularly advantageous 5 in order to be able to unstack the lids which are usually stored in punched-out form after manufacture. For example, preformed pressure rollers are used to generate surface roughness in the form of spacers 12 enable. By between the spacers 12 trapped air, the sliding together of the lid elements is achieved in the stack, so that they can be easily lifted from each other when unstacking. However, it is also possible to use appropriate embossing rollers in the sealing lacquer layer 5 a rough surface embossing pattern 13 provide.

A further advantageous embodiment is in accordance with 2 shown in which chemically and / or physically pretreated polyester films 4 ' be used. Chemical pretreatment can be carried out, for example, by coextrusion of the polyester films with copolymers adhering to these or by physical methods such as etching. This increases the adhesive adhesion of the polyester films 4 ' in such a way that on the additional composite materials, such as the pre-varnish 10 as well as the primer 8th , can be dispensed with. This results in a simplified procedure in the manufacture of the cover according to the invention, but with the same stable properties.

The stability the lid according to the invention takes place against destruction based on an examination of the Puncture resistance from superficial embossed boards with a diameter of 95.5 mm compared to known aluminum lids with a thickness of 40 m. The samples are using a bolt a weight of 66.4g with an impact area of 6mm in diameter exposed. This bolt is attached to a column with centimeters, so based on this pillar the respective drop height can be set and also measured. It has been shown that the well-known aluminum covers already after the application of the Bolt at a fall height pierce by 15cm were. In the case of the lids according to the invention the drop height however, 35cm, so that an application of the aforementioned weight units a destruction the lid showed. It can thereby be shown that the cover according to the invention is a higher mechanical resilience than the aluminum covers known per se demonstrate.

In summary can be said that the cover element according to the invention meets the required material properties, as this is symmetrical Structure in its carrier material shows which is achieved by a symmetrical composite between a core layer of paper and attached to both sides of it Polyester layers is generated. This composite is metal-free and can be thus by any detection devices with regard to destruction in control easily. Furthermore, due to the symmetrical Structure the usual for plastics Occurrence of internal tensions (bowls) postponed what also by the procedure according to the invention, namely that gradual networking of the composite structures with each other is achieved. The lid according to the invention is suitable for closing of food containers and is otherwise Microwaveable.

1

cover

2

support material

3

Core layer / paper

4,4 '

polyester sheets (Pretreated)

5

sealing layer

6

Printing lacquer layer

7

Glue

8th

primer

9

sealing wax

10

printing undercoat

11

imprint

12

spacer

13

surface rough embossed pattern

Claims (12)

Cover ( 1 ) for closing food containers with an at least three-layer carrier material ( 2 ), which on its side facing the container with a sealing layer ( 5 ) is provided, characterized in that the carrier material ( 2 ) a symmetrical bond with a core layer of paper ( 3 ) and on both sides of these attached polyester layers ( 4 . 4 ' ) is. Lid according to claim 1, characterized in that the polyester layers ( 4 . 4 ' ) consist of polyethylene terephthalate. Lid according to claim 1 or 2, characterized in that the in the polyester layers ( 4 ' ) used polyester are chemically and / or physically pretreated on one or both surfaces. Lid according to one of claims 1 to 3, characterized in that the mass per unit area of the core layer made of paper ( 3 ) is in a range of 20-80 g / m ² . Lid according to one of claims 1 to 4, characterized in that the thickness of the polyester layers ( 4 . 4 ' ) is in a range of 8–50 m. Lid according to one of claims 1 to 5, characterized in that the sealing layer ( 5 ) a coextrudate with the adjacent polyester layer ( 4 . 4 ' ) is. Lid according to one of claims 1 to 5, characterized in that the sealing layer ( 5 ) consists of a sealing wax. Lid according to one of claims 1 to 7, characterized in that the sealing layer ( 5 ) has a rough surface. Lid according to one of claims 1 to 7, characterized in that the sealing layer ( 5 ) has a rough surface print. Lid according to claim 9, characterized in that the rough surface print in the form of geometrically arranged spacers ( 12 ) is present. Lid according to one of claims 1 to 10, characterized in that the lid ( 1 ) a print on the side facing away from the container ( 11 ) having. Lid according to one of claims 1 to 11, characterized in that that it is microwave-safe.