DE20300352U1 - Central dot-shaped printed lid elements - Google Patents

Description

MAUCHER, BORJES & COLLEAGUES

PATENT AND LAW FIRM

Patent Attorney Dipl.-Ing. W. Maucher · Patent and Attorney H. Börjes-Pestalozza

Tscheulin-Rothal GmbH Dreikönigstrasse 13

Friedrich-Meyer-Str. 23 D-79102 Freiburg i. Br.

79331 Teningen _Telephone (07 61) 79 174O

Fax (07 61)79 174 30

Our file - Please always specify

G 02 582 K

Central dot-printed lid elements Summary of the invention

The invention relates to dot-printed lid elements for closing containers, in particular food containers, by sealing.

Background of the invention

Printed, stackable lidding films or lidding film elements for sealing containers are known. One problem with such lidding films is that they usually require a suitable rough coating and/or embossing in order to be unstacked, which should ensure that the lids do not stick to one another but can be easily separated from one another.

Usually, foils such as aluminium foil are printed, provided with a layer suitable for sealing on the intended inside of the lid at least in the edge area and, if not already printed on the entire surface, with a

provided with a suitable rough coating (through fine-grained components) and transported to an embossing and punching device where the corresponding embossing is applied.

An example of a corresponding process is shown in DE-OS 198 40 981. The printing and embossing operations are carried out sequentially ("on-line") using one and the same device. By taking suitable measures to ensure that the cover elements are in register with respect to the printing and embossing stations, partial embossing can also be achieved on the cover elements, for example embossing that is adapted to print motifs.

Methods are also known for producing lid elements in which dot-shaped prints ("dots") are present on the inside, which, instead of embossing, ensure sufficient surface roughness to ensure unstackability. The advantage of this method is that there is no deformation of the material of the lid elements, which could lead to its structural weakening, and the dots are printed over the entire surface. The corresponding lid elements therefore also have the corresponding dots in the area of the sealing surface (for example, near the edge of the lid if the lid is to seal a cup-shaped container). On the other hand, it has been shown that when opening lid elements with dots over the entire surface, this only allows for uneven, jerky peeling ("peeling") after sealing, which can result in liquids such as drinks being in the container splashing and spilling. Dots and sealing layer must also be coordinated in such a way that the sealing ability is not impaired too much.

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The object of the present invention is to provide new cover elements which do not have the disadvantages mentioned and also have further advantages.
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General description of the invention

The invention relates to a dot-printed lid element for closing a container, in particular a food container,
by sealing, whereby the dot-shaped printing

on the inside of the lid element (the side that
* Close the container with the lid on the inside
facing), characterized in that the
Dot-shaped printing only in areas of the cover element
which do not serve to make contact with the container flange of a container to be closed during sealing.

It has been shown that this design of the lids provides a particularly uniform adhesion and thus a particularly good
Peeling behaviour is possible. In particular, a very even and soft peeling behaviour is achieved when opening by

Removing such a cover element, and the risk
> possible leaks are reduced.

Illustration:

Fig. 1 shows an example of a cover element according to the invention
1. 2 Pull tab; 3 Outside of the lid (not
visible); 4 Inside of the lid with dots (eg 5) and
Edge area (sealing area, approximately corresponding to the
Container flange to be sealed) 6 without dots.

The shape of the lid element is only an example
and does not limit the scope of the invention.

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Preferred embodiments and more detailed description of the invention

Preferably, the dot-shaped printing is in the central area of the lid element, while the edge area is not provided with dot-shaped printing. The printing with the material intended for dot-shaped printing can thus be carried out over the entire edge area (in which case it must be a heat-sealable material) or preferably be absent there.

The cover elements are preferably made of plastic (such as those based on polypropylene, polyethylene, polyamide or polyethylene terephthalate) or in particular metal foil, preferably aluminum foil. The tensile strength is, for example, in the range from 50 to 250 n/mm ² . Composite materials are also possible, but less preferred. Examples of composite materials are aluminum/aluminum, plastic/aluminum, plastic/paper, aluminum/paper/plastic, plastic/plastic, aluminum/paper/aluminum, aluminum/plastic / aluminum or the like.

Preferably, the side of the lid element facing the inside of the container (inside) is provided with a heat-seal coating, at least in the area of the container flange. Common materials are used for the heat-seal coating.

The dots are printed on the inside of the lid element (the side that faces the inside of a container when it is closed), if there is one, on the heat-seal coating. The individual dots can consist of several sub-units (for example dots, lines or the like).

The dots can be constructed in a pattern (e.g. the same) or can represent specific motifs (e.g. flowers, clover leaves or the like). The dots can also be applied to a rough matrix instead and thus have a rough surface themselves. "Point-shaped" means that the dots are limited in area (e.g. diameters of 0.1 to 10 mm), not that they have no surface.

Preferably, the surface of all dots takes up only 2 to 20% of the surface sections of the respective cover element f in the area of which dots are present.

The thickness of the elevation of the dots over the surface on which they are printed is, for example, in the range of 5 to 50, for example 15 to 30 μιη. The material used to print the dots is a conventional varnish suitable for printing, e.g. based on (meth)acrylate, PVC, polyesters, polyethers or polystyrene/butadiene/polyethylene or other polyolefins, or their copolymerizable mixtures, in particular clear varnishes. Roughness-causing

Admixtures may be included, such as granular materials with suitable grain diameters, for example from 1 to 50 μιη, e.g. silica grains, such as Syloid ED 5 (Grace Davison, USA), talc, silica, mica and/or organic particles, the proportion of which is, for example, 0.1 to 30, such as 0.3 to 10 wt.% based on the total mass of the material used for the dots.

Additional printing on the outside (i.e. the side facing outwards after sealing onto a container) of the lid can be present in preferred embodiments of the lid elements according to the invention, for example for printing with texts, information such as barcodes, colours and/or motifs,

and can be done using conventional processes, for example by (e.g. copper) gravure, flexographic or offset printing processes.

In addition, the lid element can have one or more tear tabs.

Additional coatings may be present on the lid element, for example clear coats on the inside and/or outside. The dots are found on the outermost layer on the inside of the lid (i.e. closest to the inside of the container).

The containers are in particular food containers, for example in the form of a cup, with a round, square or other opening cross-section, in particular made of plastic. At their opening to be closed, these containers have an edge, in particular a flattened flange, which is suitable for sealing the lid element according to the invention.

The production of such lid elements can, for example, be carried out by first printing the outside of a lid element, for example on a web of a corresponding carrier film, sequentially using one and the same device, and then subsequently applying the dots to the inside of the lid element in register with the lid shape in such a way that they are only present outside the intended connection area with the container to be closed, preferably only in the central lid area, so that there is an edge of the respective lid element which is not printed with dots.

The corresponding device corresponds to that shown in DE 198 40 981, with the difference that instead of the

shown embossing device, a further printing device for applying the dots is present, preferably after the printing device for printing on the outside, in order to enable the outside to have the most undisturbed print image possible. Further components of the device can be a punching tool for producing the individual cover elements from the film and, if desired, a stacking device.

In order to accelerate the curing or drying time of, for example, the 0 print layer on the outside or the dots on the inside, heating, air supply (e.g. warm air) and/or UV irradiation are used.

To the extent that this disclosure describes manufacturing processes, these are also to be considered as subject matter of the invention in the event that priority of the present disclosure is claimed for patent applications or other applications permitting processes.

Example:

The following example illustrates the invention without limiting it.

A lid element according to the invention (see 1 in Fig.1) consists of aluminum foil and has a tear tab 2. The outside 3 of the lid element is printed (not visible). On the inside 4 of the lid there are dots printed on a heat-sealing layer (e.g. 5), while in the edge area (sealing area, approximately corresponding to the container flange to which the seal is to be applied) 6 there are no dots.

Claims (11)

1. A dot-printed lid element for closing a container by sealing, wherein the dot-printing is present on the inside of the lid element, that is to say the side which faces the inside when the container is closed with the lid, characterized in that the dot-printing is only present in areas of the lid element which do not serve to make contact with the container flange of a container to be closed during sealing. 2. Cover element according to claim 1, wherein the dot-shaped printing is present on the inside in the central region of the cover element, while its edge region is not provided with a dot-shaped printing. 3. Lid element according to claim 2, wherein in the edge region on the inside of the lid element there is no printing with the material used for dot-shaped printing. 4. Cover element according to one of claims 1 to 3 made of a plastic or metal foil, preferably of aluminum foil. 5. Cover element according to one of claims 1 to 3 made of a composite material. 6. Lid element according to one of claims 1 to 5, which is provided with a heat-seal coating on the side facing the interior of the container (inside), at least in the region of the container flange. 7. Lid element according to one of claims 1 to 6, wherein the dot-shaped prints (dots) occupy 2 to 20% of the sections of the lid elements printed with dots. 8. Cover element according to one of claims 1 to 7, wherein the thickness of the elevation of the dots over the surface on which they are printed is in the range of 5 to 50 µm. 9. Lid element according to claim 8, wherein the thickness of the elevation of the dots over the surface on which they are printed is in the range of 15 to 30 µm. 10. Lid element according to one of claims 1 to 9, wherein an additional printing is present on the outside of the lid. 11. Cover element according to one of claims 1 to 10 with further coatings.