EP3107816B1 - Bag - Google Patents

Description

The invention relates to a bag with a jacket wall formed from at least two layers each closed by a longitudinal adhesive seam to a tube with two front ends and with the bag at the front ends closed bottoms and with a filling opening for filling with a filling material, wherein the jacket wall at least one paper layer and the at least one paper layer at least predominantly determines the load-bearing capacity and the mechanical stability of the bag, wherein the outer wall has on its outer side a layer of a plastic film which protects the at least one paper layer from moisture and has splices in a region of overlapping ends between which exist ventilation paths.

The invention thus relates to a paper bag in which the at least one paper layer, which regularly consists of kraft paper, determines the statics of the bag. The jacket wall may consist of a paper layer, but preferably also of two or more paper layers. It is also known to arrange a plastic film layer between the paper layers, in particular to form a vapor barrier for the filling material. As a result, for example, the escape of odors from the bag can be prevented.

The filling of the bag via the filling opening with contents regularly also brings an entry of air into the bag interior with it. There are therefore various measures have been taken, the venting of the bag during or after filling to possible, for example, by filling tubes or valve designs that allow air removal already during filling. While the paper layers allow the air to escape, albeit slowly, plastic layers are regularly airtight. For venting over the jacket wall perforations or sieve-like inserts must therefore be provided in the plastic layers at least in local areas. For paper sacks, there is the problem that the paper layers become saturated with moisture or moisture in the environment. They can therefore lose stability and also become unsightly due to the susceptibility of damp paper to soiling.

As an alternative, plastic bags are therefore known. These consist of at least one plastic layer with a sufficient thickness for the desired stability and strength layer thickness of for example 100 microns. It is known to provide such a foil bag with slots to allow venting. In order to avoid the escape of filling material, it is known to line the foil bag on the inside with a creped filter paper layer which retains the contents in the bag interior in the region of the slots. Such a film bag is expensive to produce and has disadvantages in processing in the manufacturing process of the bag.

By US 2007/0181459 A1 a multilayer bag is known which consists of a paper layer and a moisture-protecting plastic film as the outer layer. To form the tube by means of a longitudinal adhesive seam, the ends of the plastic film overlap and are provided in this area to allow venting with a dense pattern of perforation holes. The gluing in the overlapping area can be interrupted in places.

The present invention is therefore the object of a paper bag in such a way that its disadvantages are avoided when exposed to moisture, oh-ne this on a film bag whose statics is determined by plastic films to fall back.

To achieve this object, according to the invention a bag of the type mentioned above is characterized in that the plastic film has a thickness of 60 microns or less, and also in the region of overlapping ends is free of perforations.

The paper bag according to the invention thus has on its outer side a thin plastic film, which protects the statics of the bag-determining paper layers from moisture. The plastic film has a region of overlapping ends, in which it is glued closed with itself via a longitudinal adhesive seam to a hose. However, the corresponding splices are provided with recesses so that there are ventilation paths between them. Although the paper bag is thus protected by a surrounding plastic film against moisture, especially moisture by water vapor, still allows venting, as given by the paper layers.

The plastic film surrounding the paper bag is formed without perforations, in particular in the region of the overlapping ends of the plastic films in which the splices are located.

The bonding of the overlapping ends of the plastic film together can be done with a suitable adhesive application, but is also possible in another form, for example by local welding of the two ends together.

The plastic film on the outside of the jacket wall preferably has a thickness between 10 and 50 microns. Preferably, the plastic film is only selectively bonded to the underlying paper layer and therefore easily removable from the paper layer. As a result, the advantage is achieved that the plastic film is separable from the paper layers. This is advantageous for the recyclability of the bag after its use. However, the easy removability can also be used to remove any plastic film soiled during transport in order to be able to present the bag with an outer sizable paper layer, for example for a sale in a hardware store or the like. In this case, it is expedient if the paper sheet located under the plastic film is printed. The plastic film may in this case preferably be transparent, so that the printing on the paper layer is visible through the plastic film. The plastic film may be formed from conventional film plastics. Preferred is the use of polyethylene.

In another embodiment of the invention, the plastic film itself is printed, preferably on the facing to the underlying paper layer inside the transparent plastic film. This creates a brilliant print that is easy to read and presentable for sales purposes.

In all cases in which a transparent plastic film is used, it is expedient to form at least the underlying paper layer with bleached paper. This avoids annoying reflections that would occur in a dark background caused by unbleached kraft paper.

The only selective attachment of the plastic film to the underlying paper layer also has advantages for the venting of the bag, since the flow cross section for transporting the air is increased to the venting paths between the splices of the plastic film.

To remove the plastic film from the underlying paper layer, the plastic film may be provided with a tear-off, which may be formed by a weakening line, a protruding material bag o. Ä.

By the invention it is not excluded that the plastic film is also connected over its entire surface with the underlying paper layer.

To ensure the protective function of the plastic film against the effects of moisture, it is expedient if the plastic film is included in the folding of the floors.

The paper bag according to the invention is preferably formed with one or two kraft paper layers, although it is not excluded that at least one additional paper layer is used, in particular for considerable mechanical loads. The paper layers preferably have a basis weight of 70 or 80 g / m ² in a construction with several paper layers, while with a paper layer used a higher basis weight, for example of 120 g / m ^2, may be expedient. The paper types preferably have a TEA value (Tensile Energy Absorption) according to ISO 1924-3 in the machine direction of at least 100 J / m ² for normal kraft paper grades, of at least 180 J / m ² for "semi-extensible" kraft paper grades and of at least 240 for "extensible" kraft paper grades. These kraft papers are commonly used for paper sacks to determine their statics and strength. In contrast, the additionally provided plastic film has no function influencing the static, but serves primarily to protect the paper layers from the effects of moisture.

The formation of a paper bag according to the invention from a tubular jacket wall with folded bottoms, in particular cross bottoms or block or block bottoms, takes place in a conventional manner and will therefore not be described in more detail here.

The invention offers particular advantages when the bag has two folded bottoms, one of which is provided with a valve opening into which a flat lying, for the filling tubular tube for forming a filling channel aufbiegbares valve is inserted. The valve forms a respect to the valve opening to the bag interior facing first end and a jacket wall facing the second end. The moisture-protective formation of the bag by the plastic film surrounding the paper bag is effectively supplemented by the valve having a paper layer forming the first end which has at the second end a folded, a second film section and a second film section connected therewith via a fold line Foil layer is overlapped. Thus, the bag exterior facing second end of the paper layer is overlapped by the plastic film and thus also protected from moisture. Nevertheless, use is made at the first end of the valve of the well-sealed under the pressure of the filling material effect of the paper layers of a valve. The paper layer preferred for sealing is thus covered to the outside of the bag by the film layer and thus protected from moisture. In order to make good use of the sealing effect of the paper layer for the valve bag, it is provided that the film sections each extend over only a part of the length of the paper layer. It is also expedient if the film layer is wider than the paper layer, so the paper layer in the width direction, which is perpendicular to the longitudinal direction of the valve opening, projecting on both sides.

The valve formation is further improved in a manner known per se by inserting in the fold of the bottom in the region of the valve a reinforcing sheet of paper terminating at a distance from the second end of the valve. The reinforcing sheet facilitates the bending of the bottom opening closed by the flat wall layers of the bag to a tubular valve opening.

In a preferred embodiment, the film layer has a thickness of 30 to 50 μm, preferably 40 μm. The paper layer is preferably formed with a basis weight between 50 and 100 g / m ² , preferably 80 g / m ² . In individual cases, it is also conceivable to combine the film layer in the specified thickness with a paper layer with a different basis weight or a paper layer with the specified basis weight with a film layer of a different thickness.

Figur 1

eine lediglich schematische Darstellung der Ausbildung einer Längsklebenaht in einem überlappenden Bereich der Kunststofffolie;

Figur 2

ein durch Bodeneckeinschläge teilweise gefalteter Kreuzboden mit offenen Bodenklappen und der Positionierung eines Verstärkungsblatts für die Ventilöffnung;

Figur 3

den Kreuzboden in der Darstellung der Figur 2 mit der Positionierung eines Ventils aus einer Papierlage und einer die Papierlage an einem Ende übergreifenden Folienlage;

Figur 4

eine perspektivische Darstellung des Bodens gemäß Figur 2 und 3 in explodierter Darstellung mit dem Verstärkungsblatt und dem einzusetzenden Ventil, gebildet aus der Papierlage und der Folienlage;

Figur 5

eine Seitenansicht eines erfindungsgemäßen Sacks mit zu Darstellungszwecken leicht geöffneter Ventilöffnung mit dem Verstärkungsblatt und dem eingesetzten Ventil.

The invention will be explained in more detail below with reference to exemplary embodiments illustrated in the drawing. Show it:

FIG. 1

a merely schematic representation of the formation of a longitudinal adhesive seam in an overlapping region of the plastic film;

FIG. 2

a bottom panel partially folded cross bottom with open bottom flaps and the positioning of a reinforcement sheet for the valve opening;

FIG. 3

the cross bottom in the representation of the FIG. 2 with the positioning of a valve made of a paper layer and a film layer overlapping the paper layer at one end;

FIG. 4

a perspective view of the soil according to FIG. 2 and 3 in an exploded view with the reinforcing sheet and the valve to be inserted, formed from the paper layer and the film layer;

FIG. 5

a side view of a bag according to the invention with slightly open for illustration purposes valve opening with the reinforcing sheet and the valve used.

In FIG. 1 is only schematically illustrated the formation of the longitudinal adhesive seam in an overlapping region of the plastic film. The splices K, which line up here to form a longitudinal adhesive seam, are separated from each other by small gaps Z, can escape through the air from the bag interior to the outside, as illustrated by the arrows P in the drawing. The small clouds shown in the drawing illustrate air or gas from the bag interior before passing through the spaces Z to the outside.

Of course, other splice pattern, for example, non-linear, but extend in the overlap strip area, suitable for the practice of the invention.

In FIGS. 2 to 4 the construction of a folded bottom of a bag according to the invention is shown in a preferred embodiment. The floor is designed as a cross floor and arises from the fact that the bag wall has been made as an open, flat-lying hose with two fold lines 1. Starting from the fold lines 1 triangular pockets 2 are turned inwards and cut out so that bottom flaps 3 result, which are connected via fold lines 4 pivotally connected to the large side walls of the bag. The bottom flaps 3 are folded perpendicular to the pockets 2, resulting in the formation of a cross bottom.

Figures 2 and 3 show a folded state of the soil in which the bottom flaps 3 are not yet folded. According to FIG. 2 a reinforcing sheet 5 of paper is glued to one of the pockets, which is to form a valve opening for an inserted valve, wherein the reinforcing sheet 5 extends laterally over the fold lines 4 slightly in the region of the bottom flaps 3 and is also glued there. The reinforcing sheet 5 is preferably provided with a folded end 7 towards the bottom corner impact 6, so that the corresponding end of the reinforcing sheet 5 is reinforced in two-layered form. When later folding the bottom flaps to form the cross base of the respective located on the bottom flaps 3 edge strip of the reinforcing sheet 7 is also folded. The reinforcing sheet 7 is preferably made of a paper sheet having a basis weight between 20 and 40 g / m ² , preferably 30 g / m ² .

On according to FIG. 2 created arrangement is now according to FIG. 3 applied a combination of materials to form a valve. The material combination consists of a film layer 8 and a paper layer 9. The film layer 8 is folded over a fold line 10 and thus has an upper first film section 11 and a lower second film section 12. The film layer 8 formed in this way in the form of a lying V accommodates the paper layer 9 in that the first film section 11 engages over the upper side of the paper layer 9 and the second film section 12 over the underside of the paper layer 9. The paper layer 9 also has reinforcing reasons a folded front end 13 which is inserted to the front end of the film layer 8. The paper layer 9 is in the longitudinal direction of the Valve longer than the film layer 8 is formed, so that protrudes toward the bag interior, the paper layer 9 from the film layer 8. The film layer 8 is formed perpendicular to the longitudinal direction of the valve wider than the paper layer 9. Both the film layer 8 and the paper layer 9 extend laterally over the fold lines 4 of the bottom flaps 3 and are thus folded with the bottom flaps 3 in the formation of the folded bottom to the fold lines 4.

It thus forms a valve assembly which in the longitudinal direction of the valve, ie in FIG. 3 directed outwardly, a first end 13 and an opposite, directed to the bag interior second end 14 has.

The first end 13 protrudes beyond the front edge of the reinforcing sheet 5 and covers the reinforcing sheet 5 completely in the non-open state of the valve opening, whereby it is protected against exposure to moisture. The second end 14 is formed by the paper layer 9 and the reinforcing sheet 5, so that paper is sealed onto paper. The film layer 8 extends only over a part of the paper layer 9, so that a substantial part of the length of the valve in the region of the second end 14 consists only of paper. The length of the film layer 8 is preferably between 1/2 and 3/4 of the length of the paper layer 9.

FIG. 5 shows a side view of a filled bag, which has taken its box shape through the filling. Therefore, the typical fold lines that extend from the middle fold line 1 to the corners of the floor are recognizable. Shown here is schematically the reinforcing sheet 15, the formed of film layer 8 and paper layer 9 valve with its folded up edge strips and the overlying bottom flaps 3, which form the bottom closure and possibly with a (not shown) bottom cover sheet are covered. For recognizability of the layers of the reinforcing sheet 5, the valve 8, 9 and the folded edge strips, the valve opening is shown slightly open. The closure of the valve is usually carried out in that the bag is placed on the bottom formed with the valve, so that the filling material filled in the bag closes the valve by the paper layer 9 is pressed against the reinforcing sheet 5.

Claims (14)

1. A bag with a jacket wall composed of at least two layers closed in each case by means of a longitudinal adhesive seam to form a tube and having two front ends, and with folded bottoms closing the bag at the front ends, and with a filling opening for introducing a filling material, wherein the jacket wall has at least one paper layer and the at least one paper layer at least largely determines the load-bearing capability with filled weight and the mechanical stability of the bag, wherein the jacket wall has, on its outside, a layer of a plastic film which surrounds the at least one paper layer and protects it from moisture and, in an area of overlapping ends, has adhesion points (K) between which air removal paths (Z) are formed wherein the plastic film has a thickness of 60 µm or less, characterized in that the plastic film is free of perforations in the area of overlapping ends.
2. The bag as claimed in claim 1, characterized in that the plastic film has a thickness of between 10 and 50 µm.
3. The bag as claimed in claim 1 or 2, characterized in that the plastic film is affixed to the underlying paper layer only at points and is therefore easily removable from the paper layer.
4. The bag as claimed in one of claims 1 through 3, characterized in that the plastic film is transparent.
5. The bag as claimed in one of claims 1 through 4, characterized in that the plastic film is made of polyethylene.
6. The bag as claimed in one of claims 1 through 5, characterized in that the paper layer located under the plastic film is made of bleached paper.
7. The bag as claimed in one of claims 4 through 6, characterized in that the plastic film is printed on its inside facing toward the underlying paper layer.
8. The bag as claimed in one of claims 3 through 7, characterized in that the plastic film is provided with a tear-open aid facilitating the removal from the jacket wall.
9. The bag as claimed in one of claims 1 through 8, characterized in that the plastic film is incorporated into the folding of the bottoms.
10. The bag as claimed in one of claims 1 through 9, characterized in that it has two folded bottoms, of which one is provided with a valve opening into which a flat valve is inserted which can be bent open in the shape of a tube to form a filling channel for the filling procedure and which has a first end (13) facing toward the bag interior with respect to the valve opening and a second end (14) facing toward the jacket wall, in that the valve has a paper layer (9) which forms the first end (13) and which at the second end (14) is overlapped by a folded film layer (8) having a first film portion (11) and a second film portion (12) connected to the latter via a fold line (10).
11. The bag as claimed in claim 10, characterized in that the film portions (11, 12) each extend over only part of the length of the paper layer (9).
12. The bag as claimed in claim 10 or 11, characterized in that the film layer (8) is wider than the paper layer (9).
13. The bag as claimed in one of claims 10 through 12, characterized in that a reinforcement sheet (5) made of paper, and ending at a distance from the second end (14) of the valve, is inserted into the folding of the bottom in the area of the valve.
14. The bag as claimed in one of claims 10 through 13, characterized in that the film layer (8) has a thickness of 30 to 50 µm and the paper layer (9) has a grammage of between 50 and 100 g/m².

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