EP0983947B2 - Lid and method of manufacturing it - Google Patents

Abstract

A lid (10) e.g. for a food container, consists of a carrier material (5), a printed section and a sealing layer with a shoulder region (4). The lid has a printed pattern on the inside and/or outside, and the pattern (11) has a thickness of 2-20 mu m.

Description

The present invention relates to an unembossed lid made of a carrier material, with a, based on a container to which the lid is applied, outwardly facing printing and an inwardly facing sealing layer for closing the container containing a shoulder region, wherein the inwardly facing side the Dekkels the sealing layer in the form of a printed image and the printed image corresponds to the shoulder region of the container.

It is known to provide containers, such as deep drawn or stretched containers or otherwise shaped container, at the opening with a flat annular shoulder and such containers, especially after filling, to cover, the lid rests over its entire surface on the shoulder and, for example is sealed and sealed by sealing or gluing on the shoulder. Such cups, trays, menu trays, for example, with one or more compartments, goblets, small packs, etc. are known, for example, for packaging food of all kinds, such as e.g. Dairy products, in particular yoghurt, whipped cream, sour milk, sour cream, creamer, ready-made preparations of salads or semi- or canned goods, precooked or otherwise prepared dishes, beverages, such as fruit and vegetable juices, drinking water, etc.

The lids are punched and stacked, for example, from an endless lid material present. The stack of lids are fed to a packaging machine and the isolated or unstacked lids are continuously sealed onto the already filled containers. The provided with a sealing layer lid are sealed by means of a sealing tool in the shoulder region of the container on the container edge. The separation or destacking of the lid by removal from the lid stack is not always reliably performed by the Verpakkungsmaschinen, since the adjacent lid can adhere to each other undesirable each other. For example, by embossing the lid material, the effect of sticking together can be prevented. However, embossing on the lid material has a negative effect on the printed image on the outside of the lid.

The lid material can be made of a variety of materials, depending on the requirements. Typical examples are metal foils which are coated on one or both sides with plastic. Other lid materials contain or consist of plastics in the form of monofilms or multilayer laminates. Other lidding materials may be cellulosic materials such as cellophane or paper. Also used are laminates of metal and plastic films. In order to seal the lidding material to the container rim, the lidding material is provided over its entire surface with a sealing layer, such as a sealing wax or a sealing foil, the sealing layer being provided, for example, at least on the side facing the finished package, i. pointing towards the container interior, is attached.

The lid material further serves as an information and advertising medium. For this reason, the lid material is provided on its outside with a pressure. The printing can be arranged on the uppermost layer facing outward on a finished container as a so-called straight printing. The printing can also be covered with a protective lacquer or with a protective film or the uppermost layer of the lid material can be made of transparent material and printed on the back (so-called counterpressure). The print images can be one or more colors and applied in a printing press.

The lidding material is produced, for example, in such a way that a carrier, such as a metal foil, a plastic foil or a plastic foil composite is processed by laminating or calendering with one or more further layers to form a multi-layer composite. On the side of the lid material facing inwards on the finished container, the sealing layer is applied by painting or laminating. After these processing steps, the lid material present in rolls, for example, is passed through a printing press. On the later side of the container to the outside facing side of the lid material can thus be attached to a print. Furthermore, an embossing step is to be provided, which gives the lid material, for example, a worm embossing.

In the EP-A 0 847 933 describes a lid material for containers, wherein the sealing layer is applied in the form of a printed image on the lid material and the printed image corresponds to the shoulder region of the container. The lidding material is sealed thereto via the sealing layer along the shoulder region of the container.

A disadvantage of older known methods for the production of lid materials is the high cost of materials for the full-surface coverage of the lid material with sealable material, although only a small percentage of this sealable material is ultimately needed for the sealed seam. In the cases described here, the lid material must be embossed and the embossed lid material, resp. the lid made of it, give the printed image only unfavorably.

Object of the present invention is to overcome these disadvantages and to propose a cover, which allows an economical use of individual materials and which can be reliably separated from a stack of lids.

This is achieved according to the invention with a lid having the features according to claim 1.

The print pattern is especially external, ie it represents the respective outermost layer and is exposed on its outside.

The print pattern is located entirely within the area bounded by the sealant layer.

The print pattern is applied to the inwardly facing side of the lid.

The carrier material may be a monofilm of plastic or a multilayer composite of two or more plastic layers or a metal foil or a multilayer composite of at least one metal foil or and at least one plastic foil. The carrier material can also consist of cellulose-containing material or contain cellulose-containing material. The cellulose-containing material may be coated on one or both sides, for example, with plastic or may be metallized or may have a plastic layer on one side and a metallized layer on the other side. The plastics of the carrier material may be, for example, polyolefins, such as polyethylenes or polypropylenes, polyamides, polyethylene terephthalates or polyvinyl chlorides. As metal foils, for example, steel or aluminum foils can be used. As cellulose-containing materials, for example, papers or semi-board can be used. Other substrates are z. B. Cells. The support material may have a thickness of, for example, 12-500 .mu.m, the support materials made of plastic films or metal foils or of metal and plastic foils preferably having a thickness of 12-150 .mu.m, while cover materials containing cellulosic materials, for example, a thickness of 40-500 .mu.m exhibit. The carrier materials are in particular so flexible that they can be wound into rolls (coils).

Preferred support materials comprise a transparent, opaque or opaque film or a film composite of at least one plastic of the series of polyesters, polyolefins such as polyethylenes or polypropylenes, polyamides or of cellglass or of a metal foil or of a plastic-coated metal foil or a laminate Paper with a plastic layer, such as a polyethylene terephthalate layer, which in turn may be metallized.

The carrier material may also have a barrier to gases, vapors and moisture. Barrier layers may, in addition to the metal foils mentioned, be, for example, films made of plastics, such as polyvinylidene chloride or ethylvinyl alcohol, or they may be a layer of ceramic materials, such as the oxides or nitrides of silicon or aluminum, which are in a thin layer , eg in the range of 10 to 500 nanometers, have been deposited on a carrier film in a vacuum thin film process. Examples of further barrier layers are metallic layers, e.g. made of aluminum, which are deposited by sputtering on the carrier.

On the - at the later finished container - outwardly facing side of the lid, a print can be arranged. The printing on the substrate can be done by any known printing method, e.g. Book, offset, flexo, screen, helio and copper gravure. The choice of which printing process to use depends on the desired print quality, the respective technical conditions and the number of copies. Preference is given to flexographic printing (also called aniline or rubber printing) and gravure printing, such as copper gravure printing, or helical printing. The printing on the outside of the support material may, for example, additionally be overcoated by means of a protective lacquer or by means of a Kaschierhilfsmittels or an adhesive may also be a transparent film, for example of polyethylene terephthalate, polyamide, polyolefins, such as polyethylene or polypropylene or a glass layer, but then in general Improvement of the protection of the printed image is printed in reverse printing, are laminated to the substrate.

On the side of the lid facing the inside of the container, which is a finished container, a sealing layer and a printed pattern are applied. The sealing layer and the printing pattern are mounted in the form of printed images on the substrate. The sealing layer can be applied to the carrier material in a preceding or back-fed printing press, ie before or after the production of the outside printed image. The printing pattern can be applied to the carrier material in the same or a preceding or back-fed printing machine, ie simultaneously with, before or after the production of the sealing layer. The printing pattern is expediently applied using the same printing form which prints on the sealing layer. The printing pattern can advantageously be made of a primer and / or bonding agent and a sealing wax or can only be from a sealing wax. Preference is given to the use of a primer or adhesion promoter and a sealing lacquer. The adhesion agent, resp. The primer and the sealing wax are successively applied in a printing machine, for example by a book, offset, flexo, screen, heli, gravure or copper gravure, preferably by a flexo or gravure printing on the substrate. The high negative print pattern means that 0.1 to 20%, suitably 1 to 10%, of the inwardly facing surface of the lid is covered with the print pattern and the remaining area is free from the print pattern. For example, the print patterns may be the same or unevenly distributed dot or Strip or line or line grid and so on.

The sealant layer, as well as the print pattern, can contain or consist of a sealing lacquer, for example from the series of polyolefins and preferably polyethylenes, or the vinylacrylic copolymers or the acrylic polymer-containing lacquers or the epoxy lacquers. The sealing layer, as well as the printing pattern can also contain the sealing wax and a primer or primer, for example from the series of polyesters or vinyl polymers. The primer or primer is advantageously applied to the carrier and the sealing wax on the primer or primer.

In addition to the sealing waxes mentioned, it is also possible to use dispersions or lacquers, both solvent-based and solvent-free lacquers, such as polymer-containing lacquers, e.g. based on PVC, PVC / PVAC, PVDC or acrylates, for forming the printing pattern. The solids content in the paints should be as high as possible and the proportion of solvents should be as low as possible. By analogy, the dispersions and paints must be druckmaschinengängig.

The present invention also relates to a method for producing lids from a carrier material, with respect to a container on which the lids are applied, outwardly facing printing and an inwardly facing sealing layer, wherein the inwardly-facing sealing layer by means of a printing process on the carrier material is attached and the printed image corresponds to the shoulder region of the container for closing containers, with an endless and in particular annular shoulder region.

The method is carried out according to the features of claim 8.

Preferred is a method for producing lid material according to the present invention in which the inwardly facing sealing layer and the inward-facing, printed pattern, as well as the outward-facing printing - such as advertising, advertising or information printing, etc. - in a printing press by bilateral Printing the lid material can be applied.

Exemplary give the FIGS. 1 to 4 the invention in different embodiments again. FIG. 1 is a schematic view of a cup and a section through a lid according to the invention. The FIGS. 2, 3 and 4 represent plan views of the insides of lids with different print patterns.

The FIG. 1 shows by way of example and schematically a cup 1 of side wall 2, bottom 3 and upper edge termination, which forms the shoulder 4. After filling the cup 1, for example, with a food or a drink, such as yogurt, jam, dried fruit, a chocolate preparation or other dessert or drinking water or fruit and vegetable juices, the cup 1 is covered with the lid 10 and the lid 10 along the shoulder 4 sealed onto the cup 1. The lid 10 contains a carrier material 5, attached to it a printing 6 and a protective layer 7, for example in the form of a protective lacquer or a protective film. On the against the container, resp. the container inside, directed side of the substrate 5 is in the shoulder 4 of the container 1, the sealing layer of primer 8 and sealing wax 9 applied only in places, namely corresponding or approximately corresponding to the image of the annular shoulder 4 of the cup 1. On the lid 10 is the Sealant layer of primer 8 and sealing wax 9 therefore applied only or substantially only at those points on the carrier 5, which come into contact with the shoulder 4. This is indicated schematically by the dotted lines. For the present example, this would mean that the sealing layer 8, 9 has been printed annularly on the carrier 5. It goes without saying that the printed image of the sealing layer can deviate slightly from the shoulder region 4 of the cup 1. For example, in the case of a very wide shoulder 4, the printed image of the sealing layer 8, 9 may be narrower, for example 1 to 50% narrower than the width of the shoulder of the container 4, or to compensate for machine inaccuracies, the area of the printed image of the sealing layer 8, 9 by a few percent, such as 1 to 25%, be chosen greater than the contact surface between the cover 10 and shoulder region 4. The print pattern 11 is also exemplified by primer 8 and sealing wax 9 is formed. For corrosion-sensitive cover materials, eg metal foils, it is advisable to apply Primer 8 over the entire surface as protection against aggressive substances.

In the FIGS. 2, 3 and 4 In plan view, covers 10 with different print patterns 11 are shown. In FIG. 2 the print pattern 11 can be seen in the form of a pattern of dots 12. The printing pattern 11 is within the printed sealing edge of the sealing layer 8.9 printed on the carrier 5. In the Figures 3 and 4 is the print pattern 11 in the form of a grid of Einzelstrichen- or stripes 13, for example, in parallel resp. radial arrangement, recognizable. The printing pattern 11 is also printed in this case within the printed edge of the seal from the sealing layer 8,9 on the carrier 5.

The present lidding material can be sealed over the sealing layer to the container rim. By choosing the sealing tool, the sealing pressure and the sealing temperature, the strength of the sealing seam can be adjusted. The sealing seam may also be provided with marking aids, for example in the form of weaker sealed partial areas in the sealed seam or by serrated sealing seam edges. Instead of the printed sealant layer, bonding with an adhesive such as a pressure sensitive adhesive or a heat and / or pressure setting adhesive may also be used. This with the proviso that the adhesive can be processed in a printing unit and the adhesive can be printed on the lid material.

The present lid material has the advantage of dealing with the starting materials extremely sparingly, in particular by the primer or primer and sealing wax is applied only sparsely in the places where they are actually needed. Typically, the primer or coupling agent will be present in amounts of from 0.2 to 30 grams, preferably from 1 to 20 grams per square meter, and the sealing wax in amounts of from 0.5 to 30 grams, preferably 1.5 to 20 grams, per square meter and especially each applied at 4 to 10 g per square meter. Since the primer, resp. Adhesive and the sealing wax usually has to be added to the processing in the printing press in a solvent, the amount of solvent to be evaporated significantly reduced. This is expressed both in the energy requirement and in the amount of solvent. Furthermore, the present method is advantageous because the production of the lid material requires less machine operation. The sealing layer need not be applied separately as a layer or film, but can be applied during the application of the printed image in the same operation and in the printing press. The print pattern spaces the lids in the stack and mutual adhesion of the lids is effectively inhibited. This unembossed lid in the stack of covers in packaging machines are reliably machine accessible.

The finished covers may further comprise a tear-open or grip tab and / or weakenings, for example in the form of perforations or scoring marks, which facilitate the opening of the container by removing the lid.

Since the sealing layer is present on the lid substantially only in the shoulder region of the opposite container, the risk is minimized that components diffuse from the sealing layer into the container contents and influence, for example, the container contents by odors or flavors.

The present invention makes it possible to provide completely transparent or almost completely transparent lid materials by the sealing wax is applied only at the points of the seal and not over the entire lid area and fully retain the properties of a completely transparent substrate. The transparent support materials thus do not deteriorate with respect to their transparency through the sealing wax and the primer.

Claims (9)

1. Non-embossed lid (10) made from a carrier material (5) with outwardly directed printing (6) and an inwardly directed sealing layer in relation to a container (1) to which the lid (10) is applied, for closing the container (1) comprising a shoulder region (4), the inwardly directed side of the carrier material (5) comprising the sealing layer (8, 9) in the form of a printed image and the printed image corresponding to the shoulder region (4) of the container, characterised in that the lid (10) is moreover provided on the inwardly directed side with a printing pattern (11) with a high negative fraction, the printing pattern (11) covering 0.1 to 20 % of the lid, the printing pattern (11) having a thickness of 2 to 20 µm sufficient to separate stacked lids (10) and the printing pattern (11) containing a sealing lacquer or an adhesion promoter and/or a primer and a sealing lacquer, wherein the printing pattern (11) is situated entirely within the region delimited by the sealing layer (8, 9).
2. Lid according to claim 1, characterised in that the printed image (11) contains a sealing layer containing polyolefins and preferably polyethylenes, or vinyl-acrylic copolymers or acrylic polymer-containing lacquers or epoxy lacquers or an adhesion promotor or primer from the group consisting of polyesters or vinyl polymers and a sealing lacquer containing polyolefins and preferably polyethylenes, or vinyl-acrylic copolymers or acrylic polymer-containing lacquers or epoxy lacquers.
3. Lid according to claim 1, characterised in that the carrier material contains non-embossed thermoplastics or a non-embossed cellophane or a non-embossed cellulose-containing material or a non-embossed metal foil or a combination of these materials.
4. Lid according to claim 3, characterised in that the carrier material contains a combination of at least one thermoplastic and/or a cellophane and/or a cellulose-containing material and/or a metal foil in the form of a multi-layer non-embossed composite material.
5. Lid according to claim 3, characterised in that the carrier material contains a barrier layer against gases, vapours and moisture from the group consisting of ceramic layers or metallised layers or a plastic film or a metal foil.
6. Lid according to claim 1, characterised in that the printing pattern (11) covers 1 to 10 % of the inwardly directed surface of the lid.
7. Lid according to claim 1, characterised in that the printing pattern (11) is a series of points (12), strokes (13) or lines distributed in a uniform or non-uniform manner.
8. Method of producing non-embossed lids (10) from a carrier material (5) with outwardly directed printing (6) and an inwardly directed sealing layer (8, 9) in relation to a container (1) to which the lid (10) is applied, for closing the container (1) comprising a shoulder region (4), the inwardly directed sealing layer (8, 9) being applied to the carrier material (5) by means of a printing process and the printed image corresponding to the shoulder region (4) of the container (1), characterised in that a printing pattern (1) with a high negative fraction, the printing pattern (11) covering 0.1 to 20 % of the lid, is applied to the inwardly directed sides of the lids entirely within the region delimited by the sealing layer (8, 9) to a thickness of 2 to 20 µm sufficient to separate stacked lids (10), and the printing pattern (11) containing a sealing lacquer or an adhesion promoter and/or a primer and a sealing lacquer.
9. Method of producing non-embossed lids (10) according to claim 8, characterised in that the inwardly directed sealing layer (8, 9) and the outwardly directed printing (6) and the inwardly directed printing pattern (11) are applied in a printing machine by printing on both sides of the carrier material.

Images