EP2110336A1 - Packaging bag - Google Patents

Abstract

Bag (10) made from a flexible packing film comprises a seam (20, 21) arranged along the edge of the bag and having a reinforcing strip (26) glued or sealed on the packing film to locally improve the tearing resistance.

Description

The invention relates to a bag made of a flexible packaging film with at least one sealing seam arranged along a bag edge.

Everyday goods are often packed in bags. A classic bag system is the stand-up pouch or the "Doy-Pack" bag form. Depending on the contents and requirements, material constructions with two to four main layers are used.

• Geringes Gewicht, daher geringe Kosten bei Herstellung und Vertrieb.
• Gestalterische Vielfalt in Form und Design.
• Grosse Robustheit (splittert nicht)
• Nach Gebrauch zweidimensional (Platz sparend) zu entsorgen.

Stand bag, such. B. Doypack stand-up pouch, enjoy because of several advantages over other types of packaging for liquid and pasty, but also for lumpy and dry media, very popular. The main advantages of pouches are:

• Low weight, therefore low production and distribution costs.
• Creative diversity in form and design.
• Great robustness (does not splinter)
• After use two-dimensional (space-saving) to dispose of.

The big commercial success of the pouches began in the 60s and 70s. In the 1980s, the stand-up bag experienced a further upswing in the demand for reducing packaging waste, especially in the area of detergents and cleaners.

• Getränke
• Lebensmittel (Food)
• Heimtiernahrung (Pet Food)
• Technische Füllgüter (Non Food), wie z. B. Waschmittel usw.

Stand-up pouches are versatile. So they can z. B. as primary and refill packages for liquids, powders, ready meals, pet food and other Füllguter application. The favorable production of such pouches is based on low material costs and low energy consumption. After use, they can be destroyed harmlessly. Stand-up pouches are stable and take up little space due to their low volume. Combined with their low weight, there are fewer disposal costs. Stand-up pouches guarantee optimum product protection and durability of the contents thanks to the possibility of sterilization and the possibility of adapting the layer structure to the medium to be packaged. Both cold and hot filling is possible manually, semi-automatically and fully automatically. Stand-up pouches can be equipped with a wide variety of closure and withdrawal systems and thus meet the special product requirements. Due to the large space available for advertising and information, an attractive appearance at the POS (point of sale) can arise. Stand-up pouches are available in a wide variety of geometries and sizes, mainly in the following market segments:

• beverages
• Food (Food)
• Pet food
• Technical non-food items, such as As detergent, etc.

• Marketingaspekte
• Verbesserte Handhabung und Gebrauchsfähigkeit durch spezielle Funktionen, wie z. B. Aufreissperforation, Easy-Open, Ausgiessvorrichtung und Zipper zum Wiederverschliessen der geöffneten Beutel.
• Leistungsstärkere Anlagen zur Konfektionierung und Abfüllung der Standbeutel
• Weiterentwicklung im Bereich der sterilisierbaren Folien
• Verpackungsverordnungen (z. B. grüner Punkt in Deutschland, Müllverordnung in der Schweiz)
• Zunehmende Akzeptanz beim Verbraucher Gründe für das Marktwachstum sind zunächst Marketingaspekte. Ausserdem wird eine verbesserte Handhabung und Gebrauchsfähigkeit durch spezielle Funktionen wie Aufreissperforation, Easy-Open, Ausgiessvorrichtung und Zipper für das Wiederverschliessen der Beutel den Erfolg steigern. Leistungsfähigere Anlagen zur Herstellung und zum Abfüllen der Standbeutel ermöglichen einen höheren Output. Die Entwicklung wird sich weiter in Richtung sterilisierbarer Folien bewegen. Verpackungsverordnungen wie der "Grüne Punkt" und die "Müllverordnung" werden den Markt für Standbeutel in Zukunft überproportional wachsen lassen. Aber auch die Akzeptanz beim Verbraucher ist für den zukünftigen Erfolg der Standbeutel entscheidend.

For the next few years, further growth in the demand for stand-up pouches is forecast. Reasons for this are:

• marketing aspects
• Improved handling and usability through special functions, such as: As tear perforation, Easy-Open, pouring device and zipper for resealing the opened bag.
• More powerful systems for packaging and filling of stand-up pouches
• Further development in the field of sterilizable films
• Packaging regulations (eg green dot in Germany, garbage ordinance in Switzerland)
• Increasing consumer acceptance Reasons for the market growth are marketing aspects. In addition, improved handling and usability through special features such as tear perforation, Easy-Open, pouring device and zipper for resealing the bags will increase the success. More efficient systems for the production and filling of stand-up pouches enable higher output. The development will continue in the direction of sterilizable films. Packaging regulations such as the "Green Dot" and the "Waste Ordinance" will allow the market for stand-up pouches to grow disproportionately in the future. But consumer acceptance is also crucial for the future success of stand-up pouches.

Above all, when liquid and pasty products are packed in stand-up pouches, these pouches should survive a fall from the shelf - usually a fall from a height of 1 to 2.5 m - safely. This behavior is checked by drop tests. Several bags of gradually larger heights are dropped onto a hard surface and the tested bags are then examined for integrity and tightness. This results in accordance with the standard DIN 53443 arithmetically h50, in which 50% of the tested bag survive the fall safely.

Stand-up pouches are usually made from 3- or 4-ply laminates, with each layer causing certain properties of the laminate. Usually a layer of polyethylene terephthalate (PET) or oriented polypropylene (oPP) is chosen on the outside because PET and oPP films can easily be printed on the inside as reverse printing, offer beautiful gloss surfaces, give the necessary rigidity to the overall composite and for the production the bag by thermal welding give the laminates the necessary thermal stability. Oriented polyamide (OPA) is often used as the second layer from the outside to give the laminate the necessary toughness and to provide the puncture resistance, e.g. As against mechanical damage caused by sharp objects, and to improve the barrier properties. For particularly good barrier properties against moisture, oxygen and others Gases or flavors can be vacuum-coated before the lamination of the individual films of one of the films with metals, metal oxides or ceramic with SiO _x . Alternatively, aluminum foils in typical thicknesses of 6 to 15 microns are used. The innermost layer of the laminate is usually polyethylene (PE) or, in particular for sterilizable applications, also polypropylene (PP) is used, these so-called sealing layers can also be made in multiple layers by blown or Castextrusion. By a multilayer structure of the sealing layer also an "easy opening" behavior can be achieved.

As a result of the sharp increase in raw material prices, customers are increasingly demanding cheaper packaging, which means that, wherever possible, the number of layers of a laminate is reduced to the technologically necessary minimum. So today is a variety of products, such. As liquid detergents, packed in bags of two-ply laminates.

In bag bag drop tests, the bags usually burst near the so-called triple point (TP). This is the point at the side seam where the welded structure of 4-ply (folded bottom, front and back of the bag) changes to two-ply (only the front and back of the bag). Either the side seam bursts just above the TP, or in one of the cover layers, starting from the TP, a crack or a crack runs, also starting from the TP, in the bottom fold along the folding axis. The latter variant of the break is by far the most frequently observed way in which such a tested bag bursts open.

The invention has for its object to improve in a bag of the type mentioned, the tensile strength of the packaging film in areas with increased risk of breakage. Another object of the invention is the production of bags with improved protection against bursting with minimal material usage. A still further object is to improve the tear strength of the packaging film, especially the bottom fold of stand-up pouches.

For solving the problem according to the invention, in order to locally increase the tensile strength of the sealing seam or the packaging film adjacent to the sealing seam in an area with increased risk of breakage, the packaging film in this area has a reinforcing strip of reinforcing film glued or sealed onto the packaging film, wherein one part of the reinforcing strip lies within the sealed seam.

In principle, all plastic films used for pouches in the prior art can be used as a packaging film as single-layer films or as multilayer laminates, with and without a barrier layer. Preference is given to a 2-ply laminate having an outer layer of PET or oPP and a sealable inner layer of polyolefins, such as PE or PP, or derivatives thereof or polyolefin-based copolymers or mixtures of the abovementioned materials.

According to the material to be packaged, the packaging film may have barrier properties against the passage of e.g. Liquids, gases, vapors, water vapor, flavors or odors. To obtain the desired barrier properties, metal foils, metallized layers, e.g. of aluminum, ceramic thin films, e.g. of silicon oxides and / or aluminum oxide deposited by vacuum deposition or plastic films e.g. from materials of the series of vinyl alcohols, eg. As the ethylene-vinyl alcohol polymers (EVOH) or the polyvinylidene chloride (PVDC) can be used. The barrier layer against moisture, oxygen and other gases or flavors is arranged as a film or film between the outer layer and the sealing layer, a vacuum coating is carried out on the inside of the outer or inner layer.

The individual plastic films and optionally an aluminum foil of the laminate are interconnected by laminating adhesive. Lacquer lamination can be carried out with aqueous, solvent-based or solvent-free laminating agents. Suitable laminating adhesives can contain solvents or solvent-free or hydrous. Examples of laminating adhesives are solvent-borne, solvent-free or aqueous acrylate adhesives or polyurethane adhesive systems. Preferably, laminating adhesives based on polyurethane are used.

On the outside, based on the later produced from the laminate bag, the laminate may be provided with an optionally over-painted print pattern. The printing pattern can also be designed as a counterpressure on the backside of the plastic film forming the outer side of the bag.

The individual plastic films of the packaging film can be transparent, translucent or opaque. They can be clear or partially or completely colored.

In a stand bag with a front and a back and one folded around a folding axis and sealed between the front and back in lateral longitudinal sealing bottom fold of the reinforcing strip covers the applicable as an area with increased risk of break transition of the folding axis of the bottom fold in the lateral longitudinal sealing seams the folding axis and is folded sealed in the longitudinal sealing seams.

The reinforcing strip preferably extends between the lateral longitudinal sealing seams over the entire length of the bottom fold. But it can also be provided in the region of each of the lateral longitudinal sealing seams depending on a reinforcing strip.

The reinforcing strips are preferably arranged symmetrically with respect to the folding axis and on the side of the packaging film forming the bottom fold, which faces the inside of the bag.

Conveniently, the plastic material of the reinforcing strip and the plastic material of the sealing layer of the packaging film thereof Polymer class on.

Preferably, the packaging film is a multilayer, in particular a two-ply, preferably a PET / PP, PET / PE or oPP / PE laminate.

The reinforcing strip may be a single-layer plastic film of e.g. PE or PP, polyolefin-based derivatives or copolymers or mixtures of the aforementioned materials. However, the reinforcing strip is preferably a multilayer, in particular a three-layer, preferably a PP / PET / PP or PE / PET / PE laminate.

Since it was observed in case trials that a rupture of a bag usually originates from the triple point, bags are reinforced locally at this weakest point by inserting a further film layer. It has proved to be particularly advantageous to thermally weld the reinforcing strips firmly to the bottom fold prior to the production of the bags. It would also be conceivable to previously bond the reinforcing strips to the bottom fold, i. the reinforcing strip can be laminated to the bottom fold, for example by means of a reactive adhesive system.

Experiments with stand-up pouches according to the invention have shown that the drop height h50 (according to DIN 53443) can be increased by 20 to 100% compared to conventional stand-up pouches with otherwise unchanged laminate structures and sealing settings. As a result, application-specific drop heights can be achieved with cost-effective laminates for such stand-up pouches by either reducing the layer thicknesses of the individual layers of a laminate or z. B. a 3-layer structure is replaced by a 2-ply. Both lead to a desired cheapening of the bag, but without adversely affecting the functionality of the respective packaging.

Particularly advantageous is a reinforcing strip of a 3-layer PP / PET / PP, resp. PE / PET / PE laminate proved.

Fig. 1

eine Frontansicht eines Doypack-Standbeutels;

Fig. 2

eine Sicht auf die Standfläche des Beutels von Fig. 1;

Fig. 3

einen Schnitt durch den Beutel von Fig. 1 nach der Linie I-I;

Fig. 4

einen Schnitt durch den Beutel von Fig. 1 nach der Linie II-II.

Further advantages, features and details will become apparent from the following description of preferred embodiments and from the drawing; this shows schematically in

Fig. 1

a front view of a Doypack bag;

Fig. 2

a view of the footprint of the bag of Fig. 1 ;

Fig. 3

a cut through the bag of Fig. 1 after the line II;

Fig. 4

a cut through the bag of Fig. 1 after the line II-II.

An in Fig. 1 illustrated doypack pouch 10 with a vertical pouch axis z has a front 12, a back 14 and sealed between front 12 and back 14 in a known manner bottom fold 16 in the form of along a horizontal folding axis f by 180 ° on itself folded strip of material. The upstanding from a footprint 18 of the bag 10 front and rear sides 12, 14 are connected by lateral longitudinal sealing seams 20, 21 with each other. At the bag end remote from the standing surface 18, the front and rear sides 12, 14 are connected to one another via a transverse sealing seam 22. In the bottom region of the bag, ie in the area between the standing surface 18 and the folding axis f located at a distance a from the standing surface 18 of the bottom fold 16, the bottom fold 16 between the front and back 12, 14 in the lateral longitudinal sealing seams 20, 21 welded , Between the lateral longitudinal sealing seams 20, 21 extends from the folding axis f of the bottom fold 16 to the bottom surface 18, a bottom seam 23. The bottom seam 23 connects the front and the rear wall 12, 14 with the bottom fold 16. Here terminates one of the boundary lines of the bottom seam 23rd on the standing surface 18. The upper boundary line 24 extends arcuately from the side longitudinal sealing seams 20, 21 starting from the height of the fold line f, with a shortest distance from the standing surface 18 in the middle between the longitudinal sealing seams 20, 21. The curved course of the upper The boundary line 24 is selected such that the bottom fold 16 of the unfilled bag folded into the interior of the bag is filled during filling of the bag Bag 10 unfolds and thus forms the bottom 25 of the bag 10 ( Fig. 2 ).

As in the 3 and 4 shown, the bottom fold 16 is provided on the side facing the bag interior with a respect to the folding axis f symmetrical reinforcing strip 26. The reinforcing strip 26 extends over the entire width of the bag 10 and is welded between bottom fold 16 and front and back 12, 14 in the lateral longitudinal sealing seams 20, 21 of the bag 10. Between the lateral longitudinal sealing seams 20, 21 is the reinforcing strip 26, with the exception of a narrow, immediately following the longitudinal sealing seams 20, 21 adjacent edge zone, substantially above the upper boundary line 24 of the bottom seam 23 and is no longer with the front and back 12, 14, but only connected to the bottom fold 16 of the bag 10.

The vulnerability of the bag 10 in terms of bursting after a fall is in the vicinity of the so-called triple point TP. This is the point on the lateral longitudinal sealing seams 20, 21 where the welded structure of the sealing seam of 4-ply (folded bottom fold 16, front 12 and back 14) changes to two-ply (only front 12 and back 14). Either one of the longitudinal sealing seams 20, 21 bursts just above the triple point TP, or in one of the front or back sides 12, 14, starting from the triple point TP, a crack or a crack runs, likewise starting from the triple point TP , in the bottom fold 16 along the folding axis f.

The advantageousness of the stand bag according to the invention compared with a conventional stand-up bag will be demonstrated below by way of examples.

example 1

From a 2-ply laminate consisting of a 23 micron thick PET film (Hostaphan RNK Mitsubishi) and a 100 micron thick, 7-ply blown PP film stand-up pouches with a filling volume of 0.5 liters according to the invention by previously sealing a reinforcing strip of 60 μm thick PP film onto the bottom fold and, for comparison, making it without local reinforcement of the bottom fold.

The 7-ply PP blown film has the structure A / B / A / B / A / B / A with a layer thickness distribution of 20/12/12/12/12/12/20 (all figures in μm), the layers A being Moplen Basell EP310D and Basell Adflex Q100F layers B.

The 60 μm thick PP film used as the reinforcement strip consists of a blend of Basell 70% Moplen EP310D and Basell's 30% Adflex Q100F (in% by weight).

Both bag types were filled with 0.5 liter of water and tested before and after steam sterilization for 30 minutes at 121 ° C and 1.2 bar by means of drop tests. The determined drop heights h50 according to DIN 53443 are summarized in Table 1. The improvement in h50 values is 23 to 27%, with the additional material used for the reinforcing strip being less than 2%. <u> Table 1 </ u> bag type Drop height h50 before sterilization Drop height h50 after sterilization Bottom fold with reinforcement strips 2.63 m 2.38 m Bottom fold without reinforcement strip 2.13 m 1.87 m

Example 2

From a 2-ply laminate consisting of a 12 micron thick PET film (Hostaphan RNK Mitsubishi) and a 100 micron thick, 7-ply blown PP film (as in Example 1) stand-up pouches with a capacity of 0.5 liters according to the invention by previously sealing a reinforcing strip of a 3-layer laminate PP / PET / PP consisting of two 60 μm thick PP films and a 12 μm thick PET film (Hostaphan RNK from Mitsubishi) and, for comparison, those without local reinforcement of the bottom fold.

The two 60 μm thick PP blown films of the laminate, with which the bottom fold was reinforced, consist of a blend of 80% Moplen EP310D from Basell and 20% Adflex Q100F from Basell (data in% by weight).

Both bag types were filled with 0.5 liter of water and tested before and after steam sterilization for 30 minutes at 121 ° C and 1.2 bar by means of drop tests. The determined drop heights h50 according to DIN 53443 are summarized in Table 2. The improvement in h50 values is 56 to 93%, with the additional material used for the reinforcing strip being less than 3%. <u> Table 2 </ u> bag type Drop height h50 before sterilization Drop height h50 after sterilization Bottom fold with reinforcement strips 1.93 m 2.68 m Bottom fold without reinforcement strip 1,00 m 1.72 m

The test results show that only by a local reinforcement of the bottom fold of the bag both before and after a sterilization a significantly improved robustness of the bag against sudden stress could be achieved.

The bags produced according to the invention with local reinforcement of the bottom fold now permit a reduction in the thicknesses of the packaging films used for the production to such an extent that the drop heights h50 to be achieved for the corresponding applications are just reached. This saves material, which also reduces the amount of waste and complies with the desire for better sustainability of the packaging.

The inventive concept of local, targeted reinforcement at particularly vulnerable points of a package can be applied to all types of flexible bag packaging and is not limited to stand-up pouches. In particular, the provision of local reinforcements according to the invention at particularly endangered locations of flexible packaging makes it possible to reduce the number of layers of the substantially packaging-forming laminate, which leads to cost savings.

Claims (11)

Bag made of a flexible packaging film with at least one sealing seam (20, 21) arranged along a bag edge,
characterized in that for locally increasing the tensile strength of the sealing seam (20, 21) or of the sealing film (20, 21) adjacent packaging film in an area with increased risk of breakage of the packaging film in this area glued or sealed to the packaging film reinforcing strip (26) of a reinforcing film, wherein a part of the reinforcing strip (26) lies within the sealing seam (20, 21). A bag according to claim 1, characterized in that in a stand-up pouch with a front side (12) and a rear side (14) and one around a folding axis (f) folded and between the front (12) and back (14) in lateral longitudinal sealing seams (20, 21) sealed bottom fold (16) of the reinforcing strip (26) before the valid as an area with increased risk of break transition of the folding axis (f) of the bottom fold (16) in the lateral longitudinal sealing seams (20, 21) the folding axis (f) and folded in the Longitudinal sealing seams (20, 21) is sealed. Bag according to claim 2, characterized in that the reinforcing strip (26) extends between the lateral longitudinal sealing seams (20, 21) over the entire length of the bottom fold (16). Bag according to claim 2 or 3, characterized in that the reinforcing strips (26) are arranged symmetrically to the folding axis (f). Bag according to one of claims 2 to 4, characterized in that the reinforcing strips (26) point towards the inside of the bag Side of the packaging film are arranged. A bag according to any one of claims 2 to 5, characterized in that the plastics material of the reinforcing strip (26) and the sealing layer of the packaging film belong to the same polymer class. Bag according to one of claims 2 to 6, characterized in that the packaging film is a multilayer, in particular a two-ply, preferably a PET / PP, PET / PE or oPP / PE laminate. Bag according to claim 7, characterized in that the laminate is a metal foil or a metallic vapor deposition layer, in particular of aluminum, deposited by deposition from the vacuum ceramic thin films, in particular of silicon oxides and / or alumina, or plastic films in particular of materials of the series of vinyl alcohols, preferably the ethylene-vinyl alcohol polymer (EVOH) or the polyvinylidene chloride (PVDC) as a barrier layer against moisture, oxygen and other gases or flavors as a layer or film between the outer layer and the sealing layer. Bag according to one of claims 2 to 8, characterized in that the reinforcing strip (26) is a multi-ply, in particular a three-ply, preferably a PP / PET / PP or PE / PET / PE laminate. Bag according to one of claims 2 to 9, characterized in that the reinforcing strip (26) is thermally welded to the bottom fold (16). Bag according to one of claims 2 to 9, characterized in that the reinforcing strip (26) by means of a reactive adhesive system on the bottom fold (16) is laminated.

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