EP0807587A1 - A bag made of a flexible packing material - Google Patents

Abstract

The tear-off part is formed by a weaker part, in the form of a perforation or separation in the packaging material and extending over all or part of the bag periphery. The weaker part is covered with at least one film-forming mass. After packaging, the contents of the bag are protected. The contents are removed by breaking the covering film-forming mass by pulling or bending it. The film-forming mass is thicker near the weak part then in the rest of the bag.

Description

The present invention relates to bags made of flexible packaging material with a tear zone and coated with film-forming compositions.

It is known to fill foods into bags, such as tubular bags, and to seal the bag by sealing. The contents of the bag can be removed, for example, by tearing open the tubular bag. Depending on the type of packaging material, the tearing process can be difficult. In particular, flexible packaging materials made from stretchy or tough plastics are difficult to tear open and the contents removed. This is why a scribing aid is very often stamped on a sealed seam. At most, it is possible to open the bag, however, the contents of which can very often not be removed cleanly, or the bag has to be torn open beyond the scribing aid, which is often very difficult for the consumer. It has also already been proposed to provide, for example, tubular bags with a tear strip. This tear strip can be pulled off over the circumference of the bag, the packaging material dividing and the bag thus being opened. However, this is a very complex process because the tear strip has to be installed in the layered packaging of the packaging material.

The object of the present invention is to provide a bag which contains a tear-open aid which can be attached at any point and advantageously in an edge region and the bag can be opened easily, the contents of the bag being released in such a way that the contents are removed without further manipulation of the opening can be.

According to the invention this is achieved in that the tear zone is a weakening in the packaging material and the area of the weakening is covered with a film-forming mass and after the packaging process a content is protected by the bag and a pulling or kinking movement to remove the content of the bag overlaps the overlapping one film-forming mass breaks open and the bag releases the contents.

Bags according to the present invention are understood to mean, for example, flat bags, sealed edge bags, space bags or tubular bags. Sealed edge bags and tubular bags are preferred.

Essentially all known flexible packaging materials can be used as flexible packaging material, also called packaging materials, packaging materials, packaging films, etc. will. The packaging materials should be machine-compatible, ie suitable for use on packaging machines. The packaging materials include those made of paper, optionally laminated with barrier layers and / or with plastics, or made of cellophane or packaging materials containing aluminum foils, such as aluminum foils provided with sealing layers and occasionally further plastic layers, or packaging materials made of plastic foils or of plastic foils which contain or are coated on both sides with paper or metal foils or plastic packaging materials that contain a barrier layer such as a plastic barrier layer, ceramic barrier layer or a metallic barrier layer.

Examples of plastics which can be used are polyolefins, such as polyethylenes or polypropylenes, polyamides, polyvinyl chloride or polyester, etc., in each case as a monofilm or as a film composite or, using different plastics, as a multilayer film composite. Barrier layers such as e.g. Ethyl vinyl alcohol barrier layers, or ceramic resp. glass-like or metallic barrier layers may be arranged. The plastic films or film composites can have a thickness of, for example, 10 to 100 μm, preferably 30 to 50 μm.

The packaging material can be coated on one or both sides, preferably on the side facing inwards in the bag produced therefrom, with a sealing layer, for example a sealing lacquer or a sealing film made of, for example, polyolefins, such as polyethylenes. For example, for impermeable heat-sealed bags, a sealing layer containing 6 to 7 g / m ² sealing wax is sufficient.

The packaging material is advantageously used as continuous or roll goods.

A weakening is applied to the packaging material in the area of the tear zone provided for the bag. The weakening of the packaging material can be mechanical, e.g. by cutting knives, chemical, e.g. by solvent, thermally, e.g. by laser beams, in the form of a cut, a perforation, a notch, etc. The severing is preferred. The weakening can be rectilinear or curved and the weakening can be designed such that it extends around the entire circumference or parts of the circumference of the respective pouch in the case of the pouch which is produced from the flexible packaging material.

The area of weakening on the bag according to the invention is covered with a film-forming mass. With the area of weakening, not only does the weakening itself become special also the adjacent parts of the packaging material, for example the area between 2 and 20 mm, preferably 5 and 10 mm, adjacent to the weakening, understood.

The bag according to the invention can only be coated with the film-forming composition in the area of the weakening, but such a bag is advantageously completely coated with the film-forming composition. The film-forming mass in particular represents the printing on the bag.

In an advantageous embodiment, the film-forming mass is thicker in the area of the weakening than in the remaining area of the bag. The film-forming mass can be one layer or a plurality, for example two, three, four, five, six, etc. layers, of film-forming masses. The film-forming mass covers and closes the previously applied weakening and restores tensile strength to the packaging material in the weakening area.

The film-forming mass, or the total amount when using a plurality of layers of film-forming masses lying one above the other, can advantageously be in the range of the weakening in amounts of 2 to 8 g / m ² , expediently 3 to 6 g / m ² and advantageously 3.5 to 5 g / m ² applied. Outside the weakening range, the film-forming composition can be applied, for example, in amounts of 1 to 7 g / m ² , expediently 1 to 5 g / m ² and advantageously 1 to 4 g / m ² .

To produce a film-forming composition, it is possible, for example, to use lacquer paints made from volatile constituents, such as solvents, and non-volatile constituents, such as film formers, resins, plasticizers, auxiliaries, dyes, pigments, fillers, etc. Printing inks are preferred as film-forming compositions, containing dyes or pigments, solvents, fillers, other additives and binders. Resins, varnishes, nitrocellulose, polyamides, vinyl resins, rosins, rosin resins, maleate resins, shellac etc. are advantageous as binders. The paint colors are in particular printing inks and can be printed on the weakened flexible packaging material by means of a printing machine. The printing not only represents the film-forming mass, but also the decorative, and occasionally also informative, printing for the bags. The printing on the packaging material can be applied on the outside of a bag or on the inside facing side or on both sides.

As a film-forming material, substances can also be converted into a plastic form, such as softened or melted, and applied as a film to the packaging material, on the outside of a bag or on the inside or on both sides.

The film-forming composition can be applied by an extrusion coating. Examples of suitable extrusion coatings are polyolefins, such as polyethylenes or polypropylenes, or materials containing polyvinyl chloride.

Coatings by means of hot-melt compositions, also called hot-melt coating compositions, are also included with film-forming compositions. These are, for example, solid, viscoelastic or viscoplastic materials at normal temperature, preferably based on resins, waxes, thermoplastics and elastomers, if appropriate with the addition of fillers, antioxidants, lubricants and the like, which are tough when heated after passing through a thermoplastic area - or melt thin melts.

The film formation on the packaging material by means of the film-forming compositions can also be carried out using chemically drying paints. The chemically dried paints contain cross-linked macromolecules, which are obtained by chemical reaction and in particular by polymerisation.

The film-forming compositions can also be films, in particular low tear strength or high brittleness. The thicknesses of the foils can e.g. from 5 to 20 µm. Preferred films can contain polyolefins, such as polyethylenes or polypropylenes, polyesters or polyamides. The foils can be attached to the packaging material, on the outside of a bag or on the inward-facing side or on both sides, the adhesion of the foil or foils to the packaging material by means of laminating adhesive and / or adhesion promoters, if appropriate with additional use of corona, flame, plasma or ozone treatment. For example, the film can have sealing properties, in particular when used on the side pointing inwards on the bag. The film then simultaneously represents a sealing layer. The film can also be arranged on the packaging material as a further film-forming mass above the printing varnish.

If film-forming compounds are applied to the outside and the inside of the packaging material, these can be the same or different.

The materials of the film-forming compositions are expediently physiologically harmless and approved for food packaging.

Further examples of arrangements of film-forming masses on the packaging material are sealing waxes, e.g. from polyolefins, such as polyethylenes, which are applied to the printing ink. The film-forming composition is preferably on the side facing outward on the bag. The film-forming composition can also be applied to the side facing inwards on the bag. It can e.g. is the ink of a counterprint. A further film-forming compound in the form of a sealing wax can be arranged on the printing ink of the reverse printing. The packaging material can also have a layer of a film-forming mass, e.g. a printing varnish, and contain a sealing wax on the inside of the bag.

The present invention also relates to a method for producing a bag according to the present invention. The method can advantageously be carried out in such a way that a weakening is applied to the flexible packaging material and the weakening is then covered by at least one film-forming compound.

The above-mentioned lacquers, printing inks, extrusion layers, hot-melt compositions and etc. can be used as film-forming compositions. As a rule, it is liquid or melted paint systems. The film-forming compositions can be applied, for example, by centrifuging, spinning, flooding, pouring, rolling, spraying, brushing, printing, extruding, etc. As a rule, the flexible packaging materials are continuous material, which is why coating processes such as extrusion, spraying, rolling, printing or casting are particularly suitable.

In a particularly preferred method, the flexible packaging material is provided with the weakenings in a printing unit and then the printing is carried out with printing varnishes as a film-forming composition. In this method, the flexible packaging material is fed into a printing press, for example into a high-pressure, gravure, offset printing and in particular flexographic printing press. Examples of printing machines are front printing units, multi-cylinder, single-cylinder, in-line, flexo and vario printing machines or combinations thereof, such as flexo and gravure printing machines. The weakening is expediently applied to the flexible packaging material by a cutting mechanism, advantageously in the area of the printing cylinder, before the start of printing, or in the case of multi-cylinder machines in the area of the first printing cylinder. Then the flexible Provide the packaging material with the intended print, whereby the weakening is also overprinted and the printing varnish closes the weakening. The printing varnish is carried out, for example, in such a way that the total thickness of the printing varnish is greater in the area of the weakening than in the remaining area of the flexible packaging material. Using the register control, the printing processes can be carried out with dimensional accuracy and, in addition to a clean print image, the weakening and the area around the weakening can in particular be precisely affected by the printing varnish.

Existing bags made of flexible packaging material can be used to pack food in powdery to solid consistency. A preferred use is in the packaging of bars made of chocolate, starchy foods, fatty foods, or food preparations in the form of mixtures of chocolate with starch and / or fatty foods, all food preparations advantageously in the form of bars.

The packaging of chocolate bars and the like is preferred, since in the case of the tearing process the chocolate bar serves as a repository for tearing open the bag.

If the bags are produced from tubular material, the bags each have a transverse seam seal at the end or, if the bags are produced from flat material, the bags have a longitudinal seam seal and a transverse seam seal at the end. The seams can be sealed by cold sealing, heat sealing or by gluing.

When packaging chocolate bars, for example, the weakening is advantageously in one of the two end regions of the bag, i.e. approx. 10-30 mm from the end of the bag, which is finished with a cross seal. Tubular bags with a longitudinal seam seal and terminal transverse seam seals are particularly preferred. If the bag is torn open along the weakening, the tear continues up to a maximum of the entire circumference of the bag, although the longitudinal seam sealing prevents tearing. The kinked end piece of the bag remains attached to the longitudinal seam and the longitudinal seam seal. The contents of the bag can now be easily pushed out or consumed directly from the packaging, the broken piece of bag remaining connected to the remaining bag via the longitudinal seam and not forming a piece of bag to be disposed of individually or falling onto the floor.

FIGS. 1 to 6 explain the present invention in more detail by way of example.

Figure 1 shows schematically the production of a tubular bag.

Figure 2 shows schematically the view of a tubular bag.

Figures 3, 4 and 5 show another tubular bag from the front and back, as well as in the torn state.

FIG. 6 shows a section through the packaging material in the area of a weakening.

According to FIG. 1, the packaging material 10, which is already provided with the weakenings and, for example, a varnish over the weakenings in the form of a multi-color print, is unwound from a supply roll and fed to the packaging process. The arrow 11 indicates the filling material insertion and the longitudinal seam sealing 12 and the transverse seam sealing 13 are carried out continuously with the filling material insertion, a packing unit 14 being created in each case. A cutting device 15 divides the material into tubular bags 16 with the transverse seams 17 and the longitudinal seam 19.

The tubular bag 16 is shown in FIG. The longitudinal seam 19 is located on the back and the tubular bag 16 is closed at both ends with transverse seams 17. The dot-dash line 18 indicates the weakening, which is located in the region of one end of the tubular bag 16 and is covered, for example, with a printing varnish.

FIGS. 3 and 4 show a further tubular bag 16 with the transverse seams 17 at both ends and the longitudinal seam 19. In FIG. 4, the weakening 18, which is located under the print pattern produced by means of printing varnish, is shown in broken lines. If the pack is stressed, for example by gripping the pack at the transverse seams 17 and pulling it apart, the pack separates along the weakening 18 and pulling and, for example, simultaneous folding, tears the film material further, generally along a tear line 20, which is shown in dotted lines in FIG. 3. The tear line 20 ends at the longitudinal seam 19, since there is a material accumulation or. Material thickening has arisen due to the folding and sealing. The tubular bag 16 is thus opened along its circumference, except for the area of the longitudinal seam 19, and the contents can be easily removed, for example by pushing it out from the end. The two parts of the tubular bag 16 hold together with the longitudinal seam 19 and can then be disposed of together.

Figure 5 shows the tubular bag 16 with the transverse seams 17 and the longitudinal seam 19 in a torn shape. The kinked bag part 27 is connected to the rest of the tubular bag 16 via the packaging material of the longitudinal seam 19. The tearing took place along the weakening 18 and continued over the tear line 20 to the longitudinal seam 19. The content 26, e.g. a chocolate bar, the tubular bag 16 can now be easily removed or consumed directly from the package.

FIG. 6 shows a section through the packaging material 10 in the area of the weakening 18. The weakening 18 was carried out, for example, on a plastic film 21 and the weakening 18 represents a severing of the plastic film. The plastic film 21 is on the side facing outward on the bag a multi-layer, usually multi-colored, print with the printing varnishes 23, 24 and 25 attached. When designing the print image, an additional layer of a printing varnish 24 was applied in the area of the weakening 18, as a result of which the total thickness of the printing varnish layer increased compared to the rest of the packaging material 10 and the weakening was securely covered, sealed and the packaging material 10 was given a tensile strength again. In some cases, the packaging material 10 can be provided with a sealing layer 22, in particular a sealing wax, on the side facing inwards on the bag. Sealing varnish 22 is used primarily for later sealing of the seams, but can support the effect of printing varnish 23, 24, 25.

Claims (12)

Bags made of flexible packaging material with a tear zone, coated with film-forming compositions,
characterized in that
that the tear zone is a weakening in the packaging material and the area of the weakening is covered with at least one film-forming mass and after the packaging process a content is protected by the pouch and a pulling or kinking movement to remove the contents of the pouch breaks up the covering film-forming mass and that Bag releases the contents. A bag according to claim 1, characterized in that the film-forming mass or the film-forming masses is thicker in the area of the weakening than in the remaining area of the bag. Bag according to claim 1, characterized in that the film-forming mass or the film-forming masses in the region of the weakening in amounts of 2 to 8 g / m ² , advantageously 3 to 6 g / m ² and advantageously 3.5 to 5 g / m ² is applied. A bag according to claim 1, characterized in that the weakening is a perforation or a cut and the weakening extends over an entire circumference or a partial area of the circumference of the pouch. Bag according to claim 1, characterized in that the weakening is applied over the contents of the bag in an edge region. A bag according to claim 1, characterized in that the packaging material contains at least one film-forming composition in the form of printing by means of lacquer colors, preferably on the bag directed towards the outside. A bag according to claim 1, characterized in that the packaging material contains at least one sealing layer, preferably a sealing layer directed against the inside of the bag. A bag according to claim 1, characterized in that the bag has transverse seam seals at the end or that the bag has a longitudinal seam seal and terminally transverse seam seals A method of making a bag according to claim 1,
characterized in that
a weakening is applied to the flexible packaging material and the weakening is overlaid by means of at least one film-forming mass. A method according to claim 9, characterized in that the weakening is applied to the flexible packaging material in a printing press and the weakening is overlaid by printing by means of at least one printing lacquer layer in the printing press. Use of the bag according to claim 1 for packaging food in powdery to solid consistency. Use of the bag according to claim 11 for packaging bars made of chocolate, starchy foods, fatty foods or mixtures of chocolate with starchy and / or fatty foods.

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