Packaging for free-flowing products, consisting of a heat-sealed bag

Abstract

Packaging for free-flowing products consisting of a tubular bag composed of a flexible material. One end, which lies flat when the bag is filled, is formed by two broad-face panels lying flat against one another and narrow-face panels that are folded back by center fold lines between the opposite edges of the narrow-face panels, and positioned between the marginal areas of the broad-face panels. A side fold connects each narrow-face panel to one broad-face panel and another side fold connects the narrow-face panel to the other broad-face panel. The fold lines extend substantially parallel to the longitudinal axis of the bag. The end of the bag is closed by a sealing weld that extends in a transverse direction to the longitudinal axis of the bag. The sealing weld is controlled to be weaker than the other welds which connect the panels to form the panels into a bag for containing the product. Preferably the outer surfaces of the panels are treated to prevent their being sealed together when folded back

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a '365(c) continuation of PCT/EP2004/012281 filed Oct. 29, 2004, which claims priority to DE Application 103 52 019.8, filed Nov. 7, 2003, each of the foregoing applications is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a packaging for free-flowing products consisting of a tubular bag composed of a flexible material, and said packaging, when full, has an end that lies flat, formed by two broad-face panels lying flat against one another and narrow-face panels that are folded inwards at both edges of said panels and lie between the latter, wherein a side fold adjoins one broad-face panel and another side fold adjoins the other broad-face panel, the end of the bag being closed by means of a sealing weld that extends substantially in a transverse direction to the longitudinal axis of the bag.

BACKGROUND OF THE INVENTION

These types of packaging bags are used as e.g. a receptacle for powdered detergents, and particularly as refill packaging, i.e. the customer opens the tubular bag and pours out the content, namely the detergent, into a long-term use bin. The empty bag can then be folded flat and disposed of in a space saving way.

Known packaging of this type are sealed on the upper side with a continuous upper welded seam that bonds both the broad-faced panel ends and the folded-in side fold ends of the narrow-faced panels to each other. The outer regions of the upper weld are therefore each four-ply, whereas the upper weld is two-ply in their middle region, i.e. only the broad-faced panels are bonded to one another. As a result, it is practically impossible to open the packaging without a utensil. Without a utensil the consumer is only able to pull it open in the middle region between the side folds, where the weld is two-ply. Opening by pulling causes ripping in the transition region between the two-ply and the four-ply weld zones. These rips proceed uncontrollably strongly in the direction of the bottom of the bag. Therefore, to be certain of being able to empty out the contents, the refill packaging has to be opened with a utensil, such as scissors. A label is therefore provided on the packaging to advise the consumer to use scissors.

A packaging bag whose external sides are respectively sealed with a sealing weld is known from WO 03/010067, the sealing weld being two-ply in the middle region and four-ply in both the outer regions. In order that such a bag can be opened as easily as possible without utensils, it is provided with a line of weakness, offset from the upper sealing weld, for example in the form of a perforation in the region of a broad-face panel. However, such a line of weakness brings the inherent danger of an unwanted opening, for example during transport or product handling.

A packaging bag, known from EP 1 163 166 B1, is also sealed with a top sealing weld that is four-ply in the side regions and two-ply in the middle region. To facilitate the opening of the bag, the sealing weld is arranged offset to the edge of the bag to form an engagement portion on the edge side and designed convexly directed towards the inside.

Finally, a packaging bag is known from EP 0 343 629 A1 with a continuous two-ply sealing weld that is triangular in shape. The regions of film sealed to one another are thus provided with a peelable coating intended to facilitate opening without a utensil. However, this packaging bag does not have any folded sides.

SUMMARY OF THE INVENTION

The object of the invention is to enable a controlled opening of this family of package, without opening utensils.

According to the invention, this object is achieved for a package of the type described in the introduction by providing the sealing weld in the region of the side folds only between the respective side fold and the neighboring broad-face panel.

Different from the family of packages of this type, the package in accordance with the application therefore has no four-ply sealing weld region in the region of the end of the bag, as the folded side folds are not sealed to each other, but rather only to the neighboring broad-face panel. In this way a problem-free opening of the package is possible—also without utensils—without the danger of uncontrolled ripping.

In order to reliably prevent the respective side folds to be sealed when the package is being sealed, the narrow-face panels in the region of the side folds lying against each other are each provided with an anti-adhesion coating.

In order to further facilitate the opening, the inner side of the tubular bag, at least in the region of the sealing weld, is designed in the known manner to have a peelable surface. To facilitate the manufacture, preferably all the inner side of the tubular bag has a peelable surface.

The tubular bag consists quite particularly preferably of a coextruded composite film of OPP and PE. Quite preferably, the peelable surface is realized such that it is formed from a sealing layer of PE with a modified blend, such as polybutene.

In order to facilitate the opening process and to offer the consumer a sufficiently large region to use his hands, the sealing weld is offset from the edge of the bag end.

In order to improve transport and storage and to ensure a good drop strength, such that, for example, the sealing weld does not burst after the package falls from a shelf, the end of the bag is preferably turned back and attached to the external face of the bag. The attachment can be carried out, for example, by the use of hot air. Turning over the end of the bag prevents the force generated by the fall from directly striking the sealing weld. The generated forces are directed much more to the turned back bag end, preventing damage to the sealing weld.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in more detail below, exemplified by the drawing. This shows in:

FIG. 1 is a perspective illustration a package with a sealing weld;

FIG. 2 a side view of the package shown in FIG. 1;

FIG. 3 shows the package with the sealed bag end turned back;

FIG. 4 shows the closed package before opening;

FIG. 5 shows the opening process; and

FIG. 6 a magnified fragmentary cross sectional view of the construction of the layers of two regions of film lying against one another in the tubular bag of the package.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A packaging for free-flowing products, for example powdered detergent, is shown in FIG. 1 denoted in general by 1. This packaging consists of a tubular bag 2 that is closed at the bottom with a bottom seal (not shown). The bag may be formed with front, back and side panels which are tubulated by at least one lengthwise seam (not shown) extending substantially parallel to the longitudinal axis of the bag. At the top, the tubular bag 2 is first opened and is filled with powdered product only up to the point that, when full, a bag end 3 remains flat. This bag top end 3 is formed from two broad-face panels 4 and 5 lying flat against one another and two narrow-face panels, one of which is shown at 9, that are folded inwards at both edges of said panels and lie between the broad-face panels 4, and 5, wherein a side fold line 6 joins one broad-face panel 4 with the panel 9, and the other side fold line 7 joins the other broad-face panel 5 with the panel 9. The panel 9 is folded back upon itself at a fold line 19 (FIG. 2) centrally between the broad-face panels 4 and 5.

The filled bag 2 or the flat-lying bag end 3 is sealed by means of a sealing weld 8 that extends substantially in a transverse direction to the longitudinal axis of the bag. Basic to the invention is that the sealing weld 8 in the region of the side folds 6,7 is only provided between the respective side folds 6 or 7 and the neighboring broad-face panel 4 or 5, i.e. as can best be seen in FIG. 1, the folded-back sections of the panel 9 between of the side folds lines 6,7 are not bonded to each other by a sealing weld. In this manner the total region of the sealing weld 8 is only two-ply; four-ply regions do not exist.

In order to prevent an unwanted sealing of the neighboring side folds 6,7, an anti-adhesion coating is provided at least in the region where the side folds 6,7 adjoin each other; to simplify the manufacture, the complete external side of the tubular bag can be provided with an anti-adhesion coating. The inner side 2 of the tubular bag, at least in the region of the sealing weld 8, has a peelable surface; also here, to simplify the manufacture, it is preferred that the complete inner side of the tubular bag 2 has a peelable surface. Thus, the tubular bag 2 preferably consists of a coextruded composite film of OPP and PE, as can be best discerned from FIG. 6, in which two regions of the broad-face panels 4,5, lying against one another, are illustrated in the region of the bag end 3. The coextruded composite film consists of OPP and PE; from inside to outside preferably of an inner PE layer with a modified blend, such as polybutene, this region is indicated with the reference number 10. Two coextruded polyethylene layers 11 are juxtaposed and a printing 12 is respectively provided on the external sides. This printing 12 receives an OPP layer 13 that is finally provided on the exterior with an anti-adhesion coating 14.

The closed packaging is illustrated in FIG. 4, wherein it can be seen that the regions of the side folds 6, 7 are not sealed to one another. It can also be seen that the sealing weld 8 is offset from the edge, such that in the edge region two flaps 15 remain that can be grasped by the consumer. Preferably, the end of the bag 3 is turned back and fastened to the external side of the bag 2, as is seen in FIG. 3. This fastening can be made, for example, with hot air and ensures that the package has an adequate drop resistance, i.e. if the package falls from a shelf, for example, then practically no forces act on the sealing weld 8.

To open the package 1 from its transport and sales configuration, then according to FIG. 3 the end of the bag 3 is detached from the exterior of the bag and returned to the configuration illustrated in FIG. 4. The consumer then grasps both regions 15 with both hands, as shown in FIG. 5, and pulls both ends apart, such that the bag 2 can be extremely easily opened along the sealing weld 8 and along the peelable surfaces lying against each other, without the need for a utensil.

The previously described peelable layer of film is manufactured in such a way that a polyisobutylene additive is blended in a ratio of 10 to 15% with the PE pellets used for the blown film extrusion for the inner film layer 11. In this way the whole of the inner surface is rendered peelable and on pulling apart/separating the films, there occurs a cohesive fracture, i.e. both the films sealed together are practically self-separating.

The sealing weld 8 is preferably prepared by means of special sealing jaws that have a smooth jaw geometry. The sealing temperature is preferably controlled within a very exact temperature window (tolerance 3° C.), quite preferable sealing temperatures have been found to be up to 140° C. and allow an opening of the sealing weld with opening forces of ca. 5 N/15 mm. On increasing the sealing weld temperature to above 150° C., however, the sealing weld strength increases strongly to values of around 35 N/15 mm. This value is one that practically can no longer be opened by hand and coincidentally this temperature range is suitable for making the lengthwise and bottom welds of the packaging bag 2 which are not visible in the illustrations of the bag shown in FIGS. 1-5.

Claims

1. Packaging for free-flowing products consisting of a tubular bag composed of a flexible material, and said packaging, when full, having one end, formed by two broad-face panels lying flat against one another and two narrow-face panels that are connected between said broad-face panels by fold lines, said narrow-face panels having sections which are folded back upon each other and confront said broad-face panels, wherein, respectively, one of said fold lines joins one broad-face panel with said narrow-face panel, and another of said side fold lines joins the other broad-face panel with said narrow-face panel, and at least one sealing weld that extends substantially in a transverse direction to the longitudinal axis of the bag along the top of the two broad faced panels and the narrow-face panels between them, to close the end of the bag, wherein

said at least one sealing weld between said side fold lines effecting a seal only between the sections of the narrow-face panels and the confronting broad-face panel without a seal between the folded-back sections of said narrow-face panels.

2. Packaging according to claim 1, wherein the folded-back sections of the narrow-face panels between said side fold lines and lying against one another are each provided with an anti-adhesive coating.

3. Packaging according to claim 1, wherein said tubular bag has an inner side with peelable surface, at least in the region of the sealing weld.

4. Packaging according to claim 1, wherein said tubular bag consists of a coextruded composite film of OPP and PE.

5. Packaging according to claim 3, wherein the peelable surface is formed from a sealing layer of PE with a modified blend of polybutene.

6. Packaging according to claim 1, wherein said panels have a free edge across said one end, said sealing weld being offset from said free edge.

7. Packaging according to claim 1, wherein said one end of the bag is turned back and attached to an outer side of the bag.

8. Packaging according to claim 1, wherein said bag has lengthwise and bottom welds connecting said panels to form a closed receptacle for the products, said sealing weld a providing a greater facility for being opened than said lengthwise and bottom welds.