WO2024227531A1

WO2024227531A1 - Paper bag

Info

Publication number: WO2024227531A1
Application number: PCT/EP2024/056182
Authority: WO
Inventors: Mehmet Ali BEYOGLU; Eduard Lisek
Original assignee: Dy-Pack Verpackungen Gustav Dyckerhoff Gmbh
Priority date: 2023-05-04
Filing date: 2024-03-08
Publication date: 2024-11-07

Abstract

A single-layer or multi-layer paper bag for bulk goods, having at least one material layer made of paper or coated paper, and at least having a bottom formed by cross-bottom or block-bottom folding, wherein: the bottom fold has two side flaps which are folded around side folding lines extending in the longitudinal direction of the bottom in order to form the bottom; the bottom is provided with an inner bar-shaped piece; and, on the inner side flap, the inner bar-shaped piece extends beyond the outer edge of the side flap.

Description

paper bag

The invention relates to a single- or multi-layer paper bag, wherein at least one layer consists of paper or coated paper. Additional material layers can consist of other materials, e.g. plastic films.

Such paper bags are typically used for packaging, storage and transport of various bulk goods, such as cement, granulate or other powdered or fine-grained building materials, chemicals or food. Common bag sizes are 5 kg, 10 kg or 25 kg.

Such bags are manufactured in such a way that single or multi-layered webs of paper and possibly other flat or web-like materials are formed into a continuous tube in a so-called tube machine and divided into tube pieces of suitable length, from which the bag is finally formed, e.g. by means of a cross or block bottom fold at one or both ends of the tube pieces. The bottom components of such bottoms include the corner folds of the bottom fold at the end of the bottom's longitudinal axis and the side flaps, which are folded closed around side fold lines running parallel to the bottom's longitudinal axis to close the bottom. In the middle area of the side flaps, between the inner edges of the corner folds, there is an area that has a side flap central channel that is open towards the edge, which can lead to a certain degree of leakage in the bag, for example due to certain amounts of filling material escaping through the channel opening.

Towards the end of the bag manufacturing process, the bottom fold is usually fixed using a suitable adhesive. This typically involves folding the side flaps of the bottom fold one after the other and gluing them together.

An inner bar and/or a cover sheet can be present as additional base components. An inner bar is typically inserted or glued as an inner bar sheet into the still open base fold - i.e. before the side flaps are closed - in particular to better close or seal the base opening. A cover sheet is typically glued over the closed base with the side flaps closed, preferably to increase the stability or strength of the base, or also for better sealing.

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

Figure 1 shows the addition of a cross bottom according to the state of the art. In the previously known cross or block bottom folding, the side flaps are typically folded up one after the other last.

In previously known bags, sufficient tightness is often not achieved in the area of the bottom, especially in the area of the side flap central channel and its opening at the edge of the side flaps. Against this background, it is the task The aim of the present invention is to propose a bag in which a better sealing of the bag is achieved in the bottom area.

According to the invention, the object is achieved by a bag having the features of claim 1. Advantageous embodiments are the subject of the subclaims.

The bag according to the invention is made of a single- or multi-layer web-like material with at least one material layer made of paper or coated paper and has at least one bottom formed in a cross or block bottom fold. The corner folds of the bottom fold are located at the two 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 closed around the side fold lines of the bottom fold when the bottom is closed. The side fold lines form the inner edges of the side flaps, and the outer edges of the side flaps define the width of the open bottom before the side flaps are folded closed. The bottom or - in the case of several bottoms - at least one of the bottoms is provided with an inner bar that is inserted or glued into the still open bottom fold.

When the bottom is closed, the side flaps are folded one after the other, and the side flap folded first forms the inner side flap of the closed bottom, and the side flap folded second forms the outer side flap of the closed bottom. According to the invention, the inner latch on the inner side flap has a projection over the outer edge of the side flap. Advantageously, the inner latch is wider than the open bag bottom. Preferably, the inner latch on both side flaps has a projection over the outer edges of the side flaps. Advantageously, the projection is more than 2.5 mm, more advantageously more than 5 mm. Advantageously, the projection is less than 2 cm, more advantageously less than 1 cm. The preferred dimensions of the projection can be formed on one or both side flaps of a bottom. With the protruding inner latch, a better seal of the bag bottom can be achieved, for example to avoid or reduce the escape of powdery or fine-grained bulk materials and/or for better sealing against incoming or escaping moisture or incoming or escaping liquids.

In bags with two bottoms, the internal latch described above can be present on one or both bottoms.

In a preferred embodiment, the side flaps have incisions that allow the outer edge of the side flaps to be widened. These incisions are known per se in the prior art and usually ensure that a larger area is available for gluing the side flaps after the bases have been closed. On the other hand, the incisions enlarge the outlet opening of the side flap center channel by widening the outer edge of the side flaps, so that potential leaks increase. Preferably, the invention provides that the inner bar completely covers at least one incision, particularly preferably both incisions, in at least one side flap, particularly preferably in both side flaps. Advantageously, the inner bar has a lateral overhang relative to the side edge of the side flaps formed by the respective incision. Such lateral overhangs are particularly advantageously formed relative to both side edges of a side flap formed by the incisions, and further advantageously these overhangs are present in both side flaps of a base.

In a preferred embodiment, the inner bar can consist of paper or coated paper, e.g. PE-coated paper, and/or a film. With coated paper or films or plastic films, an even better seal can be achieved, especially against moisture and/or liquids.

After fastening the inner bolt in the open base, the side flaps are folded and glued one after the other. To glue the side flap that is folded second, an adhesive contour is advantageously applied in such a way that it lies on the outer edge of the side flap that is folded first. advantageously in such a way that it covers the opening of the side flap center channel, preferably on both sides and/or over its entire length. Advantageously, this covering includes the edge sections of the side flaps formed by incisions. This better closes or seals the opening of the side flap center channel of the side flap that is closed first. The adhesive contour described above can preferably be applied to the inside of the side flap that is closed second or to the part of the inner latch there and/or after the first side flap has been closed over the outer edge of the first side flap. The adhesive contour can be particularly advantageously designed in a rectangular shape.

In a further preferred embodiment, the base is provided with a cover sheet with which the folded side flaps of the base fold are glued over. The adhesive contour for gluing the cover sheet advantageously comprises an area that covers the opening of the side flap center channel of the side flap that is folded second, preferably over its entire length and/or on both sides. With such a cover sheet, the tightness of the bag in the base area can be increased. In particular, with the adhesive contour described above, the opening of the side flap center channel of the side flap that is folded second can be better closed or sealed. In the case of bags with two bases, cover sheets and corresponding adhesives in the above-described embodiments can be present on one or both bases.

In a preferred embodiment, the cover sheet consists of a PE-coated paper and/or a film. This allows even better sealing to be achieved.

In an advantageous embodiment, the bag has two opposing bottoms, which are designed according to the invention. The side wall of the bag extends between these two bottoms. The inventive design of both bottoms with improved sealing makes it possible to achieve a particularly well-sealed bag. In another preferred embodiment, the bag is designed as an open cross-bottom or block-bottom bag which is filled via an opening opposite the bottom.

Embodiments of the invention are explained in more detail with reference to the following figures.

Fig. 1 : A bag with unfolded cross bottom according to the state of the art

Fig. 2: The open cross bottom of a bag according to the invention without inner latch

Fig. 3: The open cross bottom of a bag according to the invention with inner latch

Fig. 4: The open cross bottom of a bag according to the invention with inner latch with the edges of corner folds and side flaps behind it

Fig. 4a: The open cross bottom from Figure 4 with marking of the projections according to the invention

Fig. 5: The closing of the cross bottom of a bag according to the invention

Fig. 6a: The open cross bottom of a bag according to the invention without inner latch with cuts in the side flaps

Fig. 6b: The open cross bottom from Fig. 6a with the outer edges of the side flaps widened by incisions

Fig. 7: The open cross bottom of another embodiment of a bag according to the invention without inner latch Fig. 8: The open cross bottom according to Figure 7 with inner bolt

Fig. 9: The cross bottom of the bag according to Figure 7 with inner latch and the closed first side flap

Fig. 10: The closed cross bottom of the bag according to Figure 7 with inner latch, where both side flaps are closed

Fig. 11: Another embodiment of a bag according to the invention with closed cross bottoms and glued-on cover sheets

Fig. 12: The open cross bottom of another embodiment of a bag according to the invention without inner latch, wherein the side flaps have no incisions.

Fig. 13: The cross bottom of the bag according to Figure 12 with inner latch and the closed first side flap.

Fig. 14: The closed cross bottom of the bag according to Figure 12 with inner latch, where both side flaps are folded closed.

Figure 1 shows a bag 1 with a folded-out cross bottom 3 according to the prior art. To close the bottom, first the front side flap 8 is folded in and then the rear side flap 7 is folded on top of it, and in their overlapping area the two side flaps are glued together with the adhesive strip 9. The side flaps 7 and 8 have incisions that widen the outer edge 7a of the side flaps. The incisions form the side edges 7b of the side flaps, which run perpendicular to the outer edge 7a of the side flaps. Figure 2 shows the open cross bottom 20 of a sack 10 according to the invention without an inner latch. The bottom 20 is divided into two halves by the longitudinal axis 21 of the bottom. The corner folds 22 and 23 and the side flaps 25 and 26 are characteristic of the cross bottom fold, and are folded over the side fold lines 28 and 29 to close the bottom 20. The side wall 16 of the sack extends downwards from the bottom 20. The outer edges 25a and 26a of the side flaps 25 and 26 are widened by incisions. This forms the side edges 25b and 26b of the side flaps, which run perpendicular to the outer edges 25a and 26a of the side flaps 25 and 26 and perpendicular to the longitudinal axis 21 of the bottom.

In Figure 3, a rectangular inner bar 40 made of paper, coated paper or a film is inserted into the open cross base 20 according to Figure 2. Figure 4 shows in dashed lines the inner edges 22a and 23a of the folded corner folds and the edge areas of the side flaps 25 and 26, which lie under the inserted inner bar 40. The inner edges 22a and 23a of the corner folds, the two outer edges 25a and 26a of the side flaps and the side edges 25b and 26b of the side flaps formed by the incisions are completely covered by the inner bar. As shown in Figure 4 and marked accordingly in Figure 4a, the inner bar 40 has projections U1 and U2 relative to the outer edges 26a and 25a of the side flaps 26 and 25, respectively, as well as lateral projections U3, U4, U5, U6 relative to the side edges 26b and 25b of the side flaps 26 and 25. Between the inner edges 22a and 23a of the corner notches 22 and 23 lies the side flap center channel 41, which has an opening or an exit to the outer edges 25a and 26a of the side flaps 25 and 26. By completely covering it with the inner bar 40, a good sealing of the openings or exits of the side flap center channel 41 can be achieved.

Figure 5 shows the closing of the side flaps 25 and 26 of the cross bottom 20 of a bag 10 according to the invention. The inner bar 40 is inserted into the bottom 20. First, the front side flap 26 is closed and then the rear side flap 25 is folded onto it. In the area of the front side flap 26, the inner bar 40 has a projection U1 relative to the outer edge 26a of the side flap and projections U3 and U4 relative to the side edges 26b of the side flap. 26. This applies accordingly to the rear side flap 25, whereby the projections in this case are covered by the inner latch 40 and are therefore not visible.

Figure 6a shows an open cross bottom without an inner bolt with incisions 30, 31, 32, 33 in the side flaps for widening the outer edges 25a and 26a of the side flaps 25 and 26 by folding out the triangular areas 35, 36, 37, 38, whereby the situation with folded out triangular areas is illustrated in Figure 6b. The two cutting edges of the incisions drawn with dashed lines in Figure 6a are each provided with the reference numbers 30, 31, 32 and 33 in Figure 6b.

Figure 7 shows the open cross bottom without an inner latch of a further embodiment of a bag according to the invention. The side flap center channel 41 is formed between the inner edges 22a and 23a of the corner folds 22 and 23.

Figure 8 shows the open cross bottom 20 of a bag according to the invention according to Figure 7 with inserted inner latch 40.

Figure 9 shows the cross bottom of the bag according to the invention according to Figure 7, with the first side flap 26 closed and the second side flap 25 still open. An adhesive contour 43 shown diagonally hatched is applied, which covers the outer edge 26a of the closed side flap 26 and also the side edges 26b of the closed side flap 26. This adhesive contour 43 has a rectangular shape. When the second side flap 25 is closed, the adhesive contour 43 ensures that the outlet of the side flap center channel 41 of the side flap 26 that was closed first is well sealed. Adhesives commonly used in bag production can be used for the adhesive contour 43, such as starch adhesives or dispersion glues.

Figure 10 shows the cross bottom of the bag according to the invention according to Figure 7, with the second side flap 25 also folded closed. The second side flap 25 is folded onto the first side flap 26. A rectangular adhesive contour 44 shown diagonally hatched is applied, which covers the outer edge 25a of the side flap 25 and the side edges 25b of the side flap 25. In the In the next step, a cover sheet 50 is glued onto this adhesive contour. With such a cover sheet 50 glued onto the adhesive contour 44, a good seal of the outlet of the side flap center channel 41 of the second side flap 25 is achieved.

Figure 11 shows a bag 10 according to the invention, in which a cover sheet 50 is glued to the closed cross bottom 20. The cover sheet 50 can consist of paper, coated paper or a film. By gluing the cover sheet 50 with an adhesive contour as shown in Figure 10, a good seal is achieved at the outlet of the side flap center channel of the side flap that was closed last. In addition to the adhesive contours shown in Figures 9 and 10, further adhesive areas can be provided, for example to improve the bonding of the bottom and/or cover sheet 50.

Figure 12 shows the open cross bottom of another embodiment of a bag according to the invention without an inserted inner bar. In this case, the side flaps 25 and 26 have no cuts, so that the outer edges 25a and 26a of the side flaps 25 and 26 are narrower. In this case, there are no side edges of the side flaps perpendicular to the edges 25a and 26a.

Figure 13 shows the cross base according to Figure 12 with an inner latch 40, with the first side flap 26 already closed. A rectangular adhesive contour 43 shown diagonally hatched is applied over the outer edge 26a of the first side flap 26. When the second side flap 25 is closed, the adhesive contour 43 closes the exit of the side flap center channel of the side flap 26.

Figure 14 shows the cross bottom of the bag according to Figure 13, with the second side flap 25 now closed. A rectangular adhesive contour 44 shown diagonally hatched is applied, which covers the outer edge 25a of the side flap 25. If a cover sheet 50 is glued onto this adhesive contour 44, the side flap center channel 41 of the side flap 25 is also well sealed. In addition to In addition to the adhesive contours shown in Figures 13 and 14, additional adhesive areas may be present, for example to improve the sealing and/or the strength of the bond.

Claims

patent claims

1. Single or multi-layer paper sack (10) for bulk goods with at least one material layer made of paper or coated paper, with at least one bottom (20) formed in a cross or block bottom fold, wherein the bottom fold has two side flaps (25, 26) which are folded around side fold lines (28, 29) running in the longitudinal direction of the bottom to form the bottom, wherein the bottom is provided with an inner bar (40), characterized in that the inner bar (40) on the inner side flap (26) has a projection (U1) relative to the outer edge (25a, 26a) of the side flap.

2. Sack according to claim 1, characterized in that the inner bar (40) is wider than the open sack bottom and/or has a projection (U1, U2) on both side flaps (25, 26) relative to the outer edge (25a, 26a) of the side flap.

3. Sack according to one of the preceding claims, characterized in that the overhang (U1, U2) is more than 2.5 mm, further advantageously more than 5 mm and/or less than 2 cm, further advantageously less than 1 cm.

4. Sack according to one of the preceding claims, characterized in that the outer edge (25a, 26a) of at least one side flap (25, 26) is widened by incisions (30, 31, 32, 33) and the inner bar (40) has a lateral projection (U3, U4, U5, U6) relative to the side edges (25b, 26b) of the at least one side flap formed by the incisions.

5. Sack according to one of the preceding claims, characterized in that for gluing the side flap (25) folded shut second, an adhesive contour (43) is applied in such a way that it comes to lie on the outer edge (26a) of the side flap (26) folded shut first, advantageously in such a way that it covers the opening of the side flap center channel (41) of the side flap (26) folded shut first on both sides.

6. Sack according to one of the preceding claims, characterized in that the bottom is provided with a cover sheet (50), wherein the adhesive contour (44) for adhering the cover sheet advantageously comprises an area which covers the outer edge (25a) of the side flap (25) folded shut as the second, preferably covers the opening of the side flap center channel (41) of the side flap (25) folded shut as the second, more preferably covers it on both sides.

7. Sack according to one of the preceding claims, characterized in that the inner bar (40) and/or the cover sheet (50) comprises uncoated paper, PE-coated paper and/or film.

8. Sack according to one of the preceding claims, with two opposing bottoms formed according to the preceding claims, between which the side wall (16) of the sack extends.

9. Sack according to one of claims 1 to 6, characterized in that the sack is designed as an open cross-bottom or block-bottom sack.

10. Sack according to one of the preceding claims, characterized in that the sack is designed as a multi-layer sack, wherein the additional material layers preferably consist of paper and/or coated paper and/or plastic.