Paper bag

Abstract

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

Description

[0001] 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 be made of other materials, e.g., plastic films.

[0002] Such paper bags are typically used for packaging, storing, and transporting various bulk materials, such as cement, granules, or other powdered or fine-grained building materials, chemicals, or foodstuffs. Common bag sizes are 5 kg, 10 kg, or 25 kg.

[0003] Such sacks are manufactured, among other things, by forming single- or multi-layer webs of paper and, if necessary, other flat or web-like materials into a continuous tube in a so-called tubing machine and then dividing them into tube pieces of suitable length, from which the sack is finally formed, e.g. by means of a cross or block bottom fold at one or both ends of the tube pieces. The base components of such bases include the corner folds of the base fold at the end of the base's longitudinal axis and the side flaps, which are folded closed around side fold lines running parallel to the base's longitudinal axis to close the base. In the middle area of ​​the side flaps, between the inner edges of the corner folds, there is an area that forms a side flap center channel that is open towards the edge. This can lead to a certain degree of leakage in the sack, for example due to certain amounts of filling material escaping through the channel opening.

[0004] Towards the end of the bag manufacturing process, the bottom fold is usually secured with a suitable adhesive. This typically involves folding the side flaps of the bottom fold one after the other and gluing them together.

[0005] Additional base components may include an inner bar and / or a cover sheet. An inner bar is typically inserted or glued into the still-open base fold—i.e., before the side flaps are closed—as an inner bar sheet, particularly 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 for better sealing.

[0006] On the one hand, so-called open cross-bottom or block-bottom bags are known. These have a cross-bottom or block-bottom as a standing base and are open at the top for filling the bag. They are only closed after filling, e.g., by sewing and / or gluing. Also known are so-called valve bags, with two opposing cross-bottom or block-bottoms, one of which is designed as a standing base and the other as an opposing valve base. A valve tube is inserted into the bottom of the bag to fill it. This tube is then sealed after filling, e.g., by welding.

[0007] From DE 20 2021 102 384 U1 and DE 20 2015 004 129 U1, bags for bulk goods with a cross-folded bottom provided with an inner bar are known.

[0008] Fig. Figure 1 shows the prior art folding of a cross-bottom. In the previously known cross-bottom or block-bottom folding, the side flaps are typically folded closed one after the other.

[0009] In previously known bags, sufficient sealing is often not achieved in the bottom area, particularly in the area of ​​the side flap center channel and its opening at the edge of the side flaps. Against this background, the object of the present invention is to propose a bag in which a better seal is achieved in the bottom area.

[0010] 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.

[0011] 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-fold or block-fold manner. The corner tucks of the bottom fold are located at both ends of the bottom's longitudinal axis, and the side flaps of the bottom fold run essentially parallel to the bottom's longitudinal axis and are folded closed around the side fold lines of the bottom fold when the bottom is folded in. 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 multiple bottoms - at least one of the bottoms is provided with an inner bar that is inserted or glued into the still-open bottom fold.

[0012] When the base is added, the side flaps are folded closed one after the other, and the side flap folded first forms the inner side flap of the closed base, and the side flap folded second forms the outer side flap of the closed base. According to the invention, the inner bar on the inner side flap has a projection beyond the outer edge of the side flap. Advantageously, the inner bar is wider than the open bag base. Preferably, the inner bar on both side flaps has a projection beyond the outer edges of the side flaps. Advantageously, the projection is more than 2.5 mm, further advantageously more than 5 mm. Advantageously, the projection is less than 2 cm, further advantageously less than 1 cm. The preferred dimensions of the projection can be formed on one or both side flaps of a base.The protruding inner bar can be used to achieve better sealing of the bag bottom, for example to prevent or reduce the escape of powdery or fine-grained bulk materials and / or to provide better sealing against incoming or outgoing moisture or incoming or outgoing liquids.

[0013] In bags with two bottoms, the internal bar described above can be present on one or both bottoms.

[0014] In a preferred embodiment, the side flaps have incisions that allow a widening of the outer edge of the side flaps. 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 floors have been added. 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. For this purpose, the inner bar advantageously has a lateral overhang relative to the side edge of the side flaps formed by the respective incision.Such lateral projections are particularly advantageously formed relative to both side edges of a side flap formed by the incisions, and further advantageously these projections are present on both side flaps of a base.

[0015] In a preferred embodiment, the inner bar can be made of paper or coated paper, e.g., PE-coated paper, and / or a film. Coated paper or films or plastic films can achieve even better sealing, particularly against moisture and / or liquids.

[0016] After the inner bar has been fastened in the open base, the side flaps are folded closed one after the other and glued. Advantageously, for gluing the side flap folded second, an adhesive contour is applied such that it lies on the outer edge of the side flap folded first, advantageously such that it covers the opening of the side flap center channel, preferably on both sides and / or over its entire length. Advantageously, this coverage encloses 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 folded first. The adhesive contour described above can preferably be applied to the inside of the side flap folded second or to that part of the inner bar and / or after the first side flap has been folded over the outer edge of the first side flap.Particularly advantageously, the adhesive contour can be rectangular.

[0017] 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. Advantageously, the adhesive contour for gluing the cover sheet comprises an area that covers the opening of the side flap center channel of the side flap 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 folded second can be better closed or sealed. In the case of bags with two bases, cover sheets and corresponding adhesives in the embodiments described above can be present on one or both bases.

[0018] In a preferred embodiment, the cover sheet consists of a PE-coated paper and / or a film. This allows for even better sealing.

[0019] In an advantageous embodiment, the bag has two opposing bottoms 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 allows for a particularly well-sealed bag.

[0020] 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.

[0021] Embodiments of the invention are explained in more detail with reference to the following figures. Fig. 1: A bag with an 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 bar Fig. 3: The open cross bottom of a bag according to the invention with inner bar Fig. 4: The open cross bottom of a bag according to the invention with inner bar with the edges of corner folds and side flaps behind it Fig. 4a: The open cross base from Fig. 4 with marking of the supernatants according to the invention Fig. 5: Adding 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 bar with cuts in the side flaps Fig. 6b: The open cross base from Fig. 6a with 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 bar Fig. 8: The open cross base according to Fig. 7 with inner bolt Fig. 9: The cross bottom of the bag according to Fig. 7 with inner latch and the first side flap closed Fig. 10: The closed cross bottom of the bag according to Fig. 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 an inner bar, wherein the side flaps have no incisions. Fig. 13: The cross bottom of the bag according to Fig. 12 with inner latch and the first side flap closed. Fig. 14: The closed cross bottom of the bag according to Fig. 12 with inner latch, where both side flaps are folded closed.

[0022] Fig. Figure 1 shows a bag 1 with a folded-out cross-shaped bottom 3 according to the prior art. To close the bottom, the front side flap 8 is first folded in, followed by the rear side flap 7, which is then folded over it. The two side flaps are glued together in their overlapping area with the adhesive strip 9. The side flaps 7 and 8 have notches that widen the outer edge 7a of the side flaps. The notches form the side edges 7b of the side flaps, which run perpendicular to the outer edge 7a of the side flaps.

[0023] Fig. Figure 2 shows the open cross-bottom 20 of a bag 10 according to the invention without an inner bar. The bottom 20 is divided into two halves by the bottom longitudinal axis 21. Characteristic of the cross-bottom fold are the corner tucks 22 and 23 as well as the side flaps 25 and 26, which are folded closed around the side fold lines 28 and 29 to close the bottom 20. The side wall 16 of the bag 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 bottom longitudinal axis 21.

[0024] In Fig. 3 is in the open cross bottom 20 according to Fig. 2 a rectangular inner bar 40 made of paper, coated paper or a film is inserted. Fig. Figure 4 shows in dashed lines the inner edges 22a and 23a of the folded corner tucks and the edge areas of the side flaps 25 and 26, which lie beneath the inserted inner bar 40. The inner edges 22a and 23a of the corner tucks, 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 Fig. 4 and in Fig. 4a, the inner rule 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 exit to the outer edges 25a and 26a of the side flaps 25 and 26. The complete overlap with the inner bar 40 allows for good sealing of the openings or exits of the side flap center channel 41.

[0025] Fig. Figure 5 shows the closing of the side flaps 25 and 26 of the cross-shaped 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 folded 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, as well as 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 concealed by the inner bar 40 and are therefore not visible.

[0026] Fig. Figure 6a shows an open cross bottom without inner bolts 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 in Fig. 6b. The two cutting edges of the Fig. 6a The incisions marked with dashed lines are in Fig. 6b are each provided with the reference numbers 30, 31, 32 and 33.

[0027] Fig. Figure 7 shows the open cross-shaped bottom without an inner bar of another 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.

[0028] Fig. 8 shows the open cross bottom 20 of a bag according to the invention according to Fig. 7 with inserted inner bolt 40.

[0029] Fig. 9 shows the cross bottom of the bag according to the invention according to Fig. 7, with the first side flap 26 folded 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 folded side flap 26 and also the side edges 26b of the folded side flap 26. This adhesive contour 43 is rectangular in shape. When the second side flap 25 is folded closed, the adhesive contour 43 ensures that the exit of the side flap center channel 41 of the first folded side flap 26 is well sealed. Adhesives commonly used in bag production, such as starch adhesives or dispersion glues, can be used for the adhesive contour 43.

[0030] Fig. 10 shows the cross bottom of the bag according to the invention according to Fig. 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, covering the outer edge 25a of the side flap 25 as well as the side edges 25b of the side flap 25. 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 is achieved for the outlet of the side flap center channel 41 of the second side flap 25.

[0031] Fig. Figure 11 shows a bag 10 according to the invention, in which a cover sheet 50 is glued to the closed cross-shaped bottom 20. The cover sheet 50 can be made of paper, coated paper, or a film. By gluing the cover sheet 50 with an adhesive contour as in Fig. 10 shows a good seal of the outlet of the side flap center channel of the last closed side flap. In addition to the Fig. 9 and Fig. 10, further adhesive areas can be provided, for example to improve the bonding of the base and / or cover sheet 50.

[0032] Fig. Figure 12 shows the open cross-shaped 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 notches, 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.

[0033] Fig. 13 shows the cross base according to Fig. 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.

[0034] Fig. 14 shows the cross bottom of the bag according to Fig. 13, whereby the second side flap 25 is now closed. A rectangular, diagonally hatched adhesive contour 44 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 the Fig. 13 and Fig. 14, additional adhesive areas may be present, for example to improve the sealing and / or the strength of the bond.

Claims

[1] Single- or multi-layer paper bag (10) for bulk material 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 by that the inner bolt (40) on the inner side flap (26) has a projection (U1) relative to the outer edge (25a, 26a) of the side flap. [2] Bag according to claim 1, characterized by that the inner bar (40) is wider than the open bag 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] Bag according to one of the preceding claims, characterized bythat the projection (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] Bag according to one of the preceding claims, characterized by 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] Bag according to one of the preceding claims, characterized by in that, for bonding the second folded side flap (25), an adhesive contour (43) is applied in such a way that it comes to lie on the outer edge (26a) of the first folded side flap (26), advantageously in such a way that it covers the opening of the side flap central channel (41) of the first folded side flap (26) on both sides. [6] Bag according to one of the preceding claims, characterized by that the base 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 second folded side flap (25), preferably covers the opening of the side flap central channel (41) of the second folded side flap (25), further preferably covers it on both sides. [7] Bag according to one of the preceding claims, characterized by that the inner bar (40) and / or the cover sheet (50) comprises uncoated paper, PE-coated paper and / or film. [8] Bag according to one of the preceding claims, with two opposite bottoms formed according to the preceding claims, between which the side wall (16) of the bag extends. [9] Bag according to one of claims 1 to 6, characterized bythat the bag is designed as an open cross-bottom or block-bottom bag. [10] Bag according to one of the preceding claims, characterized by that the bag is designed as a multi-layer bag, wherein the further material layers preferably consist of paper and / or coated paper and / or plastic.

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