EP4086186A1 - Bag for bulk material - Google Patents

Abstract

Sack (10) for bulk goods made of paper and/or other flat material, with at least one bottom (20) formed in a cross or block bottom fold manner, the bottom fold having two side flaps (25, 26) which are folded around side fold lines running in the longitudinal direction of the bottom to form the bottom are, the side flaps forming an overlap in the closed state, the width of the overlap being a maximum of 10 millimeters, preferably a maximum of 6 millimeters and more preferably a maximum of 4 millimeters.

Description

The invention relates to a bag for bulk goods such. As cement, granules or other powdered or fine-grained building materials, chemicals or food with at least one cross or block bottom.

Such sacks are typically made of a flat or web-like material, preferably paper and/or plastic. They are used in particular for the packaging and distribution of powdery or fine-grained bulk goods. Common sizes are 5 kg, 10 kg and 25 kg.

For the production of such bags single or multi-layer webs of sheet material such. B. paper and / or film webs, in a so-called. Tubing machine formed into an endless tube and separated into tube pieces of suitable length, from which the sack is finally formed, for example by means of a cross or block bottom fold. Towards the end of the sack manufacturing process, the bottom fold is usually fixed by a suitable adhesive. For this purpose, the side flaps of the bottom fold are often closed one after the other and glued together in the area of a comparatively wide overlap.

On the one hand, so-called open cross or block bottom sacks are known, which have a cross or block bottom as a stand-up base and are open at the top for filling the bag and are only closed after filling, e.g. B. sewn and / or glued, are. Also known are so-called valve sacks, with two opposing cross or block floors, one of which is designed as a standing floor and the other as an opposite valve floor, into which a valve tube is inserted for filling the sack, which is closed after filling, e.g. B. by welding.

figure 1 shows the addition of a cross bottom according to the prior art. In the case of the previously known cross or block bottom fold, the side flaps are typically closed one after the other last. When closed, the two side flaps usually have a comparatively wide overlap, in the area of which there is a bond to fix the bottom fold.

A sufficiently wide overlap is required for the side flaps to be glued to one another. In previously known bags, the width of the overlap ranges up to 2.5 - 5 centimeters. This requires sufficiently wide side flaps, which is associated with a corresponding amount of material. Since the sacks of this type are produced and sold in large numbers, even small material savings can lead to relevant cost advantages. Sacks are also known in which a gap remains between the closed side flaps, so that the closed side flaps do not overlap. With such sacks, however, sufficient protection of the contents in the bottom area is often not guaranteed, particularly in the case of multi-layer sacks with a foil or barrier layer. In addition, the bottom of the sack is less stable in the area of the gap.

Against this background, it is the object of the present invention to propose a sack in which material can be saved in the bottom area, with good protection of the contents and sufficient strength also being ensured in the bottom area.

According to the invention, the object is achieved by a sack with the features of claim 1. Advantageous configurations are the subject matter of the dependent claims.

The sacks according to the invention are made from a single- or multi-layer web-like material, in particular paper and/or other flat material, and have at least one bottom formed in a cross-fold or block-bottom fold. The corner folds of the bottom fold are located at both ends of the bottom longitudinal axis, and the side flaps of the bottom fold run essentially parallel to the bottom longitudinal axis and are folded shut around the side fold lines of the bottom fold when the bottom is closed. The folded side flaps have an overlap. According to the invention, the width of the overlap is a maximum of 10 millimeters, preferably a maximum of 6 millimeters and more preferably a maximum of 4 millimeters.

With these overlapping widths, the width of the overlap is reduced to well below the extent that is usually required for the side flaps to be glued to one another on conventional sack-making machines. By reducing the width of the overlap compared to previously known sacks, a significant saving in material is achieved, which also increases the environmental friendliness of the sacks, in particular if these material layers are made of plastic or other less environmentally friendly materials. The length of the piece of tubing from which the sack is made can be significantly reduced in comparison to previously known sacks with glued overlaps for the same filling volume of the sack. At the same time, due to the presence of a narrow overlap, adequate protection of the filling is ensured because a gap between the folded side flaps is avoided. The side flaps are preferably not glued to one another in the region of their overlap. The bottom fold can be fixed in any other way than by gluing the overlapping of the side flaps, e.g. by gluing on a cover sheet.

Provision is advantageously made for the side flaps to overlap by at least 1 millimeter, preferably at least 2 millimeters, more preferably at least 4 millimeters and more preferably at least 6 millimeters. Through the minimum width of the overlap better ensures good protection of the contents and good strength of the bottom of the sack.

In a preferred embodiment, a bottom of the sack is designed as a valve bottom, into which a valve for filling the sack is incorporated. Advantageously, the valve is designed as a valve tube, which is used in the area of a folded corner of the bottom fold. In a particularly advantageous manner, the inner end of the valve hose extends essentially only as far as the inner edge of the corner tuck or just before the inner edge of the corner tuck. The less overlapping of the side flaps and the reduced length of the piece of tubing from which the sack is made mean that the corner tucks also take up less material. In particular, the corner folds have a smaller width in the direction of the longitudinal axis of the floor, i. H. the corner impacts extend less far from the ends of the longitudinal axis of the floor towards the middle of the floor. In the case of valve bags, this width of the corner fold must typically be overcome by the valve hose so that the filling material can be introduced into the bag as easily as possible. Due to the less wide corner tucks, the distance to be covered by the valve hose is shorter in the sacks according to the invention, so that valve material can be saved. The valve tube is often formed from comparatively expensive material, e.g. B. from a thermal material in order to be able to weld the valve after the bag has been filled. The shortening of the valve tube according to the invention is therefore associated with significant material and cost savings. Accordingly, the base design according to the invention is particularly advantageous for a valve base. Advantageously, the valve tube is shortened in such a way that the inner end of the valve tube is shortened relative to the inner edge of the corner tuck, this shortening being preferably 3 mm, more preferably 6 mm and even more preferably 1 cm.

A valve can be used as a prefabricated, closed valve tube in the bottom fold that is still open. Alternatively, it is also possible to insert a so-called valve sheet into the still open bottom fold to form the valve, so that the valve sheet is formed into a tube by closing the side flaps becomes. In this configuration, a saving in material is also possible in that the valve sheet can be made less wide transversely to the longitudinal axis of the base.

In an advantageous embodiment, the sack has two opposite bottoms which are designed according to the invention. The side wall of the sack extends between these two floors. Due to the configuration according to the invention of both bases with a small overlap of the side flaps, a saving in material can be achieved according to the invention for both bases. One of the two bases is particularly advantageously designed as a valve base and the other as a standing base.

In another preferred embodiment, the sack is designed as an open cross-bottom or block-bottom sack, which is filled through an opening opposite the bottom.

The bag according to the invention can be constructed in one layer. In a preferred embodiment, the sack is designed as a multi-layer sack, with the material layers preferably consisting of paper and/or coated paper and/or plastic. In the case of multi-layer sacks, the material savings in bottom formation have a particularly advantageous effect.

In a further preferred embodiment, the sack is constructed in three layers, with the innermost and outermost layers of material being made of paper or coated paper, and the layer between the layers of material being made of plastic. In this way, particularly good product protection can be achieved in the area of the entire sack, including the bottom area, while at the same time the sack is very strong.

The sack is advantageously made from compostable and/or recyclable materials, in particular from paper and/or coated paper.

In another preferred embodiment, at least one of the bases is provided with an inner bar and/or a cover sheet. An inner bolt is known in Glued into the bottom fold that is still open. The folded side flaps of the bottom fold are glued over with a cover sheet. The protection of the filling goods in the base area can be increased and/or the base fold can be fixed with the inner bar and/or with the cover sheet. In the case of bags with two bottoms, inner bars and/or top sheet can be present on one or both bottoms. In the case of bases with inner bars, an opening aid, preferably a tear-open strip, can also be provided in a base, preferably in the standing base.

In a preferred embodiment, the inner bar and/or the cover sheet can be made of paper, in particular simple and/or less resistant paper, since the overlapping of the side flaps ensures good protection of the filling. In another preferred embodiment, the inner bar and/or the cover sheet consists of a PE-coated paper and/or a film. As a result, even better product protection can be achieved.

Another advantageous embodiment is the omission of an inner bar and the gluing of a cover sheet essentially over the entire bottom, as a result of which the bottom fold can be well fixed and the filling can be well protected.

In another preferred embodiment, the piece of tubing from which the sack is formed has a smooth cut on at least one, preferably both ends, in which the cutting line perpendicular to the direction of the tube has a continuous course at the ends of the piece of tubing. Such a straight cut allows, in a simple manner in terms of production technology, that a corresponding saving of material is achieved in addition to the side flaps also in the corner folds of the bottom fold.

Fig. 1:

Einen Sack mit aufgeklapptem Kreuzboden gemäß Stand der Technik

Fig. 2:

Den offenen Kreuzboden eines erfindungsgemäßen Sackes

Fig. 3:

Den offenen Kreuzboden eines erfindungsgemäßen Sackes mit Innenriegel

Fig. 4:

Das Zulegen des Kreuzbodens eines erfindungsgemäßen Sackes

Fig. 5:

Den zugelegten Kreuzboden eines erfindungsgemäßen Sackes

Fig. 6:

Den zugelegten Kreuzboden, mit einem Deckblatt überklebt

Fig. 7:

Den offenen Kreuzboden eines erfindungsgemäßen Sackes mit Ventil

Fig. 7a:

Den offenen Kreuzboden eines erfindungsgemäßen Sackes mit einem Ventilschlauch, der bis zur Innenkante des Eckeinschlages reicht

Fig. 7b:

Den offenen Kreuzboden eines erfindungsgemäßen Sackes mit einem Ventilschlauch, der nicht bis zur Innenkante des Eckeinschlages reicht

Fig. 8:

Den offenen Kreuzboden eines erfindungsgemäßen Sackes mit eingelegtem Ventilzettel

Fig. 8a:

Den offenen Kreuzboden eines erfindungsgemäßen Sackes mit eingelegtem Ventilzettel, der bis zur Innenkante des Eckeinschlages reicht

Fig. 8b:

Den offenen Kreuzboden eines erfindungsgemäßen Sackes mit eingelegtem Ventilzettel, der nicht bis zur Innenkante des Eckeinschlages reicht

Fig. 9:

Einen Papierbahnabschnitt für die Herstellung eines erfindungsgemäßen Sackes

Exemplary embodiments of the invention are explained in more detail with reference to the figures below. show:

Figure 1:

A cross-bottomed open sack according to the prior art

Figure 2:

The open cross bottom of a sack according to the invention

Figure 3:

The open cross bottom of a sack according to the invention with an inner latch

Figure 4:

Closing the cross bottom of a sack according to the invention

Figure 5:

The added cross bottom of a sack according to the invention

Figure 6:

The added cross bottom, pasted over with a cover sheet

Figure 7:

The open cross bottom of a sack with a valve according to the invention

Figure 7a:

The open cross bottom of a sack according to the invention with a valve tube which extends to the inside edge of the corner tuck

Figure 7b:

The open cross bottom of a sack according to the invention with a valve tube that does not reach the inside edge of the corner tuck

Figure 8:

The open cross bottom of a sack according to the invention with an inserted valve label

Figure 8a:

The open cross bottom of a sack according to the invention with an inserted valve label, which extends to the inside edge of the corner tuck

Figure 8b:

The open cross bottom of a sack according to the invention with an inserted valve label, which does not reach the inside edge of the corner tuck

Figure 9:

A paper web section for the manufacture of a sack according to the invention

figure 1 shows a sack 1 with the folded bottom 3 according to the prior art. To close the bottom, the front side flap 8 is folded in first and then the rear side flap 7 is folded thereon, and the two side flaps are bonded with the adhesive strip 9 at their overlapping portion. Current bag making machines require a comparatively large overlap in order to apply a strip of glue in a practical manner.

figure 2 shows a sack 10 according to the invention with an open cross bottom 20. The bottom 20 is divided into two halves by the bottom longitudinal axis 21. FIG. The corner tucks 22 and 23 and the side flaps 25 and 26, which are folded shut about the side fold lines 28 and 29 to close the bottom 20, are characteristic of the cross bottom fold. Extending downward from the bottom 20 is the side wall 16 of the sack.

In figure 3 an inner bar 40 is inserted into the open cross bottom 20 . The inner bar 40 covers the inner edges of the folded corner folds 22 and 23 and extends from the bottom longitudinal axis 21 to over the side fold lines 28 and 29. The inner bar is advantageously glued to the inner edges of the corner folds and the side flaps with a frame adhesive. Good protection of the filling material can thus be achieved.

figure 4 shows the closing of the side flaps 25 and 26 of the cross bottom 20 of a sack 10 according to the invention. First, the front side flap 26 is folded, and then the rear side flap 25 is folded thereon.

figure 5 shows the closed cross bottom 20 of a sack 10 according to the invention. In the closed state, the side flaps 25 and 26 overlap only to a small extent. The width of the overlap of the side flaps results from the distance between the edge 35 of the rear side flap 25 and the edge 36 of the front side flap 26. Since the front side flap 26 is folded in first, its edge 36 is covered by the rear side flap 25, which is then folded in. Therefore, the edge 36 of the front side flap 26 is shown in phantom, and the unobscured edge 35 of the rear side flap 25 is shown in solid line. According to the invention, the distance between the edges 35 and 36 or the width of the Overlap of the side flaps 25 and 26 a maximum of 10 millimeters. The overlap is preferably a maximum of 4 millimeters and more advantageously a maximum of 2 millimeters.

Due to the smaller overlap of the side flaps, the sack can be made more material-saving overall. Due to the small width of the overlap, an adhesive strip cannot be applied with the machines commonly used in bag production. It is therefore provided according to the invention to fix the bottom fold in a different way than by mutually gluing the side flaps in the overlapping area. For example, the bottom fold can be fixed by sticking on a cover sheet. this is in figure 6 illustrated. There the added cross bottom 20 is glued over with a cover sheet 45, which fixes the bottom fold.

figure 7 shows a variant of a sack 10 according to the invention with a cross bottom 20 that is still open, into which a valve 50 in the form of a prefabricated valve tube is inserted. Due to the narrower design of the side flaps 25 and 26, the corner tucks 22 and 23 are also narrower in the longitudinal direction of the floor. As a result, the valve tube 50 also only has to cover a shorter distance in order to bring the filling material into the sack without any problems. In this way, the valve 50 can also be produced using less material. Figure 7a shows a variant in which the valve hose 50 extends to the inner edge 24 of the corner fold 22. As a result, a little more valve material can be saved in this variant than in the variant according to FIG figure 7 , in which the valve tube extends beyond the inner edge 24 of the corner tuck 22. Figure 7b shows a variant in which the valve hose 50 is shortened at its inner end 54 opposite the inner edge 24 of the corner fold 22. This shortening is preferably 3 mm, more preferably 6 mm and even more preferably 1 cm. By design according to Figure 7b even more valve material can be saved.

figure 8 shows a variant of the sack 10 according to the invention with a cross bottom 20 that is still open, into which a valve slip 52 has been inserted to form a valve. With the closing of the side flaps 25 and 26, the valve sheet 52 becomes a valve tube shaped. In the variant according to figure 8 the inner edge 56 of the valve sheet extends somewhat further to the center of the shelf than the inner edge of the corner tuck 22. Figure 8a shows a variant with a valve sheet 52 in which the inner edge 56 of the valve sheet extends to the inner edge 24 of the corner fold 22, so that the valve sheet 52 and corner fold 22 are flush with one another at the edges 24 and 56. Figure 8b shows a variant in which the inner edge 56 of the valve sheet 52 does not reach the inner edge 24 of the corner tuck 22, so that the valve tube 52 is shortened at its inner end 54 opposite the inner edge 24 of the corner tuck 22. The shortening is particularly advantageously 3 mm, more advantageously 6 mm and even more advantageously 1 cm. As a result, even more valve material can be saved in this embodiment.

figure 9 shows a paper web section 12 for the production of a sack according to the invention on an endless paper roll 11. The fold lines of the cross-bottom fold are indicated in dashed lines. The rectangular panels 16 form the side wall 16 of the sack. The paper web sections 12 are cut off along the cutting lines 13 and 14 to form individual tube pieces. Accordingly, the cutting lines 13 and 14 represent the cutting lines of the hose pieces perpendicular to the direction of the hose. figure 7 shows cutting lines 13 and 14 formed with a smooth cut, which run steplessly perpendicular to the tube direction. With a reduced hose section length, material can be saved both in the area of the side flaps and in the area of the corner folds with a clean cut.

Claims (14)

Sack (10) for bulk goods made of paper and/or other flat material, with at least one bottom formed in a cross or block bottom fold manner, the bottom fold having two side flaps (25, 26) which, to form the bottom, are folded around side fold lines (28, 29 ) are folded, the side flaps forming an overlap when folded, characterized in that the width of the overlap is a maximum of 10 millimeters, preferably a maximum of 6 millimeters and more preferably a maximum of 4 millimeters. Sack according to Claim 1, characterized in that the width of the overlap is at least 1 millimetre, preferably at least 2 millimetres, and more preferably at least 4 millimetres. A sack according to any one of the preceding claims, wherein the base is constructed as a valve base incorporating a valve (50) for filling the sack. Sack according to the preceding claim, characterized in that the valve (50, 52) is inserted in the area of a corner fold (22, 23) of the bottom fold, the inner end of the valve (54, 56) extending substantially up to the inner edge (24) of the corner impact is enough. Sack according to Claim 3, characterized in that the valve (50, 52) is inserted in the area of a corner fold (22, 23) of the bottom fold, the inner end (54, 56) of the valve (50, 52) being opposite the inner edge ( 24) of the corner tuck (22) is shortened, the shortening being preferably 3 mm, more preferably 6 mm and even more preferably 1 cm. Sack according to one of the three preceding claims, characterized in that the valve (50) is designed as a valve tube (50) and/or as a valve sheet (52). A sack according to any one of the preceding claims, having two opposite bottoms formed according to claim 1 or 2, between which the side wall (16) of the sack extends. Sack according to Claim 1 or 2, characterized in that the sack is designed as an open cross-bottom or block-bottom sack. Sack according to one of the preceding claims, characterized in that the sack is designed as a multi-layer sack, the layers of material preferably consisting of paper and/or coated paper and/or plastic. Sack according to one of the preceding claims, characterized in that the sack is constructed in three layers, the innermost and the outermost material layer being formed from paper and the material layer lying in between being formed from plastic film. Sack according to one of the preceding claims, characterized in that the sack is made of compostable and/or recyclable materials, in particular paper and/or coated paper. Sack according to one of the preceding claims, characterized in that at least one of the bases is provided with an inner bar (40) and/or a cover sheet (45). Sack according to the preceding claim, characterized in that the inner bar comprises uncoated paper, PE-coated paper and/or foil. Sack according to one of the preceding claims, characterized in that the sack is formed from a piece of tubing which has a smooth cut on at least one, preferably both ends (13, 14).

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