Bag for bulk material

Abstract

To provide a bag allowing for economizing material in a bottom region while favorably protecting a content charged and securing strength sufficiently in even a bottom region.SOLUTION: A bag for bulk material, made of paper and / or other sheet material, includes at least one bottom formed in a cross-over or block bottom-folding scheme, in which fold portions in the bottom have two side flaps forming a bottom by being folded around side fold lines extending longitudinally of the bottom. The side flap forms an overlap in a closure state, in which the overlap has a width of 10 millimeter or smaller, preferably 6 millimeter or smaller, more preferably 4 millimeter or smaller.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a bag having at least one cross or block bottom for bulk materials such as cement, granular or other powdered or fine building materials, chemicals, or food products. [Background technology]

[0002] Such bags are typically made of flat or web-like material, preferably paper and / or plastic. They are used, among other things, for the packaging and distribution of powders or particulate bulk materials. Common sizes are 5 kg, 10 kg, and 25 kg.

[0003] To produce such bags, flat materials, such as paper and / or film webs, are formed into endless tubes in the form of so-called tubers and then singulated into tube sections of appropriate length, from which the bags are finally formed, for example by cross or block bottom folding. Towards the end of the bag production process, the bottom folds are usually secured by suitable gluing. For this purpose, the side flaps of the bottom fold are often closed one after the other and glued together with a relatively wide overlap area.

[0004] On the one hand, so-called open cross-bottom or block-bottom bags are known, which have a cross-bottom or block-bottom as a fixed bottom, are open at the top for filling the bag, and are only closed after filling, for example by sewing and / or gluing. So-called valve bags are also known, which have two opposing cross-bottom or block-bottom bottoms, one of which is designed as a fixed bottom and the other as an opposing valve bottom, into which a valve tube is inserted to fill the bag, and which are closed after filling, for example by welding.

[0005] Figure 1 shows a prior art cross bottom application. In the aforementioned cross or block bottom folding process, the side flaps are typically folded closed one after the other last. In the closed state, the two side flaps usually have a relatively wide overlap, in which area adhesive is placed to secure the bottom fold.

[0006] A sufficiently wide overlap is required to connect the side flaps to one another. In known bags, the overlap width ranges from 2.5 centimeters to 5 centimeters. This requires sufficiently wide side flaps, with corresponding material costs. Because typical bags are manufactured and sold in large quantities, even small material savings can result in significant cost advantages. Also known are bags in which gaps remain between closed side flaps to prevent the closed side flaps from overlapping. However, with this type of bag, particularly in the case of multi-layer bags with a film or barrier layer, sufficient protection of the contents in the bottom area is often not guaranteed. Furthermore, the bottom of the bag is less stable in the gap area. Summary of the Invention [Problem to be solved by the invention]

[0007] Against this background, the object of the present invention is to provide a bag which allows saving material in the bottom area while ensuring good protection of the filled contents and sufficient strength also in the bottom area. [Means for solving the problem]

[0008] According to the invention, this object is achieved by a bag having the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

[0009] The bag according to the invention is made of a single-layer or multi-layer web-like material, in particular paper and / or other sheet-like material, and has at least one bottom formed by a cross-bottom or block-bottom fold. The corner infolds of the bottom fold are located at two ends of the longitudinal axis of the bottom, and the side flaps of the bottom fold extend essentially parallel to the longitudinal axis of the bottom and, when the bottom is in a closed state, are closed around the side fold lines of the bottom fold. The folded side flaps have an overlap. According to the invention, the width of the overlap is 10 millimeters or less, preferably 6 millimeters or less, and more preferably 4 millimeters or less.

[0010] These overlap widths significantly reduce the overlap width from the dimensions typically required for bonding side flaps together on typical bag-making machines. By reducing the overlap width compared to previously known bags, significant material savings are achieved, which also increases the environmental friendliness of the bag, especially when the bag includes layers of material made of plastic or other environmentally friendly materials. The length of the tube pieces from which the bag is made can be significantly reduced for the same fill volume of the bag compared to previously known bags with bonded overlaps. At the same time, the presence of the narrow overlap continues to ensure adequate protection of the filled contents, since gaps between the closed side flaps are avoided. Preferably, the side flaps are not bonded to each other in the overlap region. The bottom fold can be secured in any way other than by gluing the side flap overlap, for example, by gluing it to a cover sheet.

[0011] Advantageously, the overlap of the side flaps is at least 1 mm, preferably at least 2 mm, more preferably at least 4 mm, even more preferably at least 6 mm. A minimum width of overlap is better in terms of ensuring good protection of the contents and good strength of the bag bottom.

[0012] In a preferred embodiment, the bottom of the bag is designed as a valve bottom, in which a valve for filling the bag is integrated. The valve is advantageously formed as a valve tube inserted in the area of ​​the corner fold of the bottom fold. It is particularly advantageous if the inner end of the valve tube extends essentially to the inner edge of the corner fold or immediately before the inner edge of the corner fold. The corner fold also requires less material, due to the reduced overlap of the side flaps or the reduced length of the tube piece from which the bag is formed. In particular, the corner fold has a reduced width in the direction of the longitudinal axis of the bottom. That is, the corner fold does not extend far from the end of the longitudinal axis of the bottom toward the center of the bottom. In the case of a valve bag, this width of the corner fold must typically be overcome by the valve tube so that the filling material can be introduced into the bag as smoothly as possible. In the case of a bag according to the present invention, fewer wide corner folds means that a shorter distance must be covered by the valve hose, thereby saving valve material. Valve hoses are often made of relatively expensive materials, such as thermal materials, in order to be able to weld the valve after filling the bag. Therefore, shortening the valve hose according to the invention is associated with significant savings in material and costs. Therefore, the bottom design according to the invention is particularly advantageous for the valve bottom. The shortening of the valve hose is designed so that the inner end of the valve hose is shortened relative to the inner edge of the corner turn-up, and this shortening amount is advantageously preferably 3 mm, more preferably 6 mm, and even more preferably 1 cm.

[0013] The valve can be inserted into the statically open bottom fold as a pre-assembled, closed valve tube. Alternatively, a so-called valve patch can be inserted into the statically open bottom fold to form the valve, and then the valve patch is formed into the tube by adding side flaps. In this embodiment, material savings are also possible, as the valve patch can be made smaller in width transverse to the longitudinal axis of the bottom.

[0014] In an advantageous embodiment, the bag has two opposing bottoms configured according to the invention. The side walls of the bag extend between these two bottoms. Due to the design of both bottoms according to the invention, with a small overlap of the side flaps, material savings can be achieved for both bottoms according to the invention. It is particularly advantageous if one of the two bottoms is designed as a valve bottom and the other as a stand bottom.

[0015] In another preferred embodiment, the bag is an open cross or block bottom bag that is filled through an opening on the opposite side of the bottom.

[0016] The bag according to the present invention can be designed as a single-layer bag. In a preferred embodiment, the bag is designed as a multi-layer bag, and the material layer preferably consists of paper and / or coated paper and / or plastic. In the case of a multi-layer bag, the material savings in the bottom formation have a particularly advantageous effect.

[0017] In a further preferred embodiment, the bag is made of three layers, with the innermost and outermost material layers being made of paper or coated paper and the middle material layer being made of plastic, in this way particularly good product protection can be achieved in the entire area of ​​the bag, including the bottom area, while at the same time ensuring high strength of the bag.

[0018] Advantageously, the bag is made from compostable and / or recyclable materials, especially paper and / or coated paper.

[0019] In another preferred embodiment, at least one of the bottoms is provided with an inner latch and / or a cover sheet. The inner latch is glued to the fold of the still-open bottom in a known manner. A cover sheet is applied over the closed side flaps of the bottom fold. The inner latch and / or cover sheet can be used to increase protection of the contents in the bottom area and / or to secure the bottom fold. In the case of a bag with two bottoms, the inner latch and / or cover sheet can be present on one or both bottoms. In the case of a bottom with an inner latch, an opening aid, preferably a tear strip, can also be provided on one bottom, preferably the upstanding bottom.

[0020] In a preferred embodiment, the inner latch and / or cover sheet can be made of paper, especially simple and / or less resistant paper, since the overlap of the side flaps ensures good protection of the contents. In another preferred embodiment, the inner latch and / or cover sheet can be made of PE-coated paper and / or film, which can provide even better protection for the contents.

[0021] Another advantageous embodiment is the omission of the inner latch and the application of a cover sheet over substantially the entire bottom, which allows for better fixing of the bottom fold and better protection of the contents.

[0022] In another preferred embodiment, the tube section from which the bag is formed has at least one, preferably both, smooth cuts, the cut lines perpendicular to the longitudinal direction of the tube section having a continuous path at the end of the tube section. Such smooth cuts allow corresponding savings in material not only in the side flaps but also in the corner folds of the lower folds in a simple manner from a production engineering point of view.

[0023] Examples of embodiments of the invention will now be described in more detail with reference to the following drawings, in which: [Brief explanation of the drawings]

[0024] [Figure 1] 1 shows a prior art bag with an unfolded cross bottom; FIG. [Figure 2] 1 shows an open cross bottom of a bag according to the present invention. [Figure 3] 1 shows an open cross bottom of a bag according to the invention with an internal latch. [Figure 4] 10A-10C show cross bottom feeding of bags according to the present invention; [Figure 5] 10A-10C show cross bottom closures of bags according to the present invention. [Figure 6] FIG. 10 shows a closed cross bottom glued with a cover sheet. [Figure 7] 1 shows an open cross bottom of a bag according to the invention with a valve. [Figure 7a] 10 shows an open cross bottom of a bag according to the invention with a valve tube extending to the inside edge of the corner fold. FIG. [Figure 7b] 10 shows an open cross bottom of a bag according to the invention with a valve tube that does not extend to the inside edge of the corner fold. FIG. [Figure 8] 1 shows an open cross bottom of a bag according to the invention with a valve patch inserted. [Figure 8a] 1 shows an open cross bottom of a bag according to the invention with a valve patch inserted that extends to the inside edge of the corner fold. FIG. [Figure 8b] 10 shows an open cross bottom of a bag according to the present invention with a valve patch inserted that does not extend to the inside edge of the corner fold. FIG. [Figure 9] 1 shows a paper web section for producing a bag according to the invention; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] Figure 1 shows a prior art bag 1 having a widened cross bottom 3. To close the bottom, first the front flap 8 is folded over, then the rear flap 7 is folded over it, and the two side flaps are glued together in their overlap area with an adhesive strip 9. Typical bag machines require a relatively wide overlap to be able to apply the adhesive strip in a practical manner.

[0026] 2 shows a bag 10 according to the present invention having an open intersecting bottom 20. The bottom 20 is divided into two halves by a bottom longitudinal axis 21. The intersecting bottom fold features corner folds 22 and 23 and side flaps 25 and 26, which are folded closed about side fold lines 28 and 29 to close the bottom 20. Extending downwardly from the bottom 20 are the side walls 16 of the bag.

[0027] In Figure 3, inner latch 40 is inserted into the open cross bottom 20. Inner latch 40 covers the inner edges of the folded corner infolds 22 and 23 and extends from the bottom longitudinal axis 21 above the side fold lines 28 and 29. The inner latch is advantageously bonded to the inner edges of the corner and side flaps by frame bonding, which provides good protection for the contents.

[0028] 4 shows the closure of the side flaps 25 and 26 of the cross bottom 20 of the bag 10 according to the present invention. The inner latch 40 is inserted into the bottom 20. The front flap 26 is folded closed first, and then the back flap 25 is folded over it.

[0029] FIG. 5 shows the closed cross bottom 20 of the bag 10 according to the invention. In the closed state, the side flaps 25 and 26 overlap only slightly. The width of the overlap of the side flaps is determined by the distance between the edge 35 of the rear flap 25 and the edge 36 of the front flap 26. Because the front flap 26 is folded first, its edge 36 is covered by the subsequently folded rear flap 25. Therefore, the edge 36 of the front flap 26 is shown as a dashed line, and the uncovered edge 35 of the rear flap 25 is shown as a solid line. According to the invention, the distance between the edges 35 and 36 or the width of the overlap between the side flaps 25 and 26 is 10 millimeters or less. Preferably, the overlap is 4 millimeters or less, and even more advantageously 2 millimeters or less.

[0030] The small overlap of the side flaps allows the bag to be formed in an overall more material-efficient manner. Because of the small overlap, adhesive strips cannot be used properly on machines typically used in bag manufacturing. Therefore, the present invention provides for securing the bottom fold by a method other than bonding the side flaps together in the overlap region. For example, the bottom fold can be secured by gluing it to a cover sheet. This is shown in Figure 6, where an additional cross bottom 20 has a cover sheet 45 glued thereon, which secures the bottom fold.

[0031] FIG. 7 shows a variant of the bag 10 according to the invention, still with an open cross bottom 20, into which a prefabricated valve tube-style valve 50 has been inserted. As a result of the narrower design of the side flaps 25 and 26, the corner folds 22 and 23 also narrow longitudinally along the bottom. As a result, the valve tube 50 only has to travel a shorter distance to successfully insert the filling material into the bag. In this way, the valve 50 can also be manufactured in a more material-saving manner. FIG. 7a shows a variant in which the valve hose 50 extends to the inner edge 24 of the corner fold 22. This means that slightly more valve material can be saved in this variant than in the variant shown in FIG. 7, in which the valve hose protrudes beyond the inner edge 24 of the corner fold 22. FIG. 7b shows a variant in which the valve hose 50 is shortened at its inner end 54 relative to the inner edge 24 of the corner fold 22. Preferably, this shortening is 3 mm, more preferably 6 mm, and even more preferably 1 cm. Even more valve material can be saved with the design according to Figure 7b.

[0032] FIG. 8 shows a variation of the bag 10 according to the invention, with the cross bottom 20 still open, into which the valve patch 52 is inserted to form a valve. When the side flaps 25 and 26 are closed, the valve patch 52 is formed into a valve tube. In the variation shown in FIG. 8, the inner edge 56 of the valve patch extends slightly further into the center of the material base than the inner edge of the corner infold 22. FIG. 8a shows a variation with the valve patch 52, in which the inner edge 56 of the valve patch extends to the inner edge 24 of the corner infold 22, so that the valve patch 52 and the corner infold 22 are flush with each other at the edges 24 and 56. FIG. 8b shows a variation in which the valve patch 52 does not extend with its inner edge 56 to the inner edge 24 of the corner infold 22, so that the valve tube 52 is shortened at its inner end 54 relative to the inner edge 24 of the corner infold 22. In particular, the shortening is advantageously 3 mm, more advantageously 6 mm, and even advantageously 1 cm. As a result, more valve material can be saved in this embodiment.

[0033] FIG. 9 shows a paper web piece 12 for producing a bag according to the present invention on a continuous paper roll 11. The fold lines for the intersecting bottom folds are shown in dashed lines. Rectangular panels 16 form the side walls 16 of the bag. The paper web piece 12 is cut along cut lines 13, 14 to form individual tube segments. Thus, cut lines 13, 14 represent the cut lines of the tube segments perpendicular to the tube direction. FIG. 9 shows the cut lines 13, 14 formed by smooth cuts, which run continuously perpendicular to the tube direction. By shortening the tube length, smooth cuts can save material both in the area of ​​the side flaps and in the area of ​​the corner folds.

Claims

1. At least one bottom is formed in a cross or block bottom fold manner; the bottom fold includes two side flaps (25, 26) folded around side fold lines (28, 29) extending in the longitudinal direction of the bottom to form the bottom; A bag (10) for bulk materials, the side flaps being made of paper and / or other sheet material that forms an overlap when the side flaps are closed, The width of the overlap is Less than 10 mm, Preferably, 6 mm or less, More preferably, it is 4 mm or less. A bag for bulk materials comprising:

2. The width of the overlap is More than 1 mm Preferably, 2 millimeters or more. More preferably, it is 4 mm or more.

2. A bag for bulk materials according to claim 1 , characterized in that

3. the bottom is formed as a valve bottom incorporating a valve (50) for filling the bag; 3. A bag for bulk materials according to claim 1 or 2, characterized in that it is

4. said valves (50, 52) are inserted in the area of ​​the corner infolds (22, 23) of the bottom fold, The inner ends (54, 56) of the valves (50, 52) extend substantially to the inner edge (24) of the corner fold.

4. A bag for bulk materials according to claim 3, characterized in that

5. said valves (50, 52) being inserted in the area of ​​the corner infolds (22, 23) of the bottom fold, the inner ends (54, 56) of the valves (50, 52) are shortened relative to the inner edge (24) of the corner infold (22); The shortening amount is preferably 3 mm, more preferably 6 mm, and even more preferably 1 cm.

4. A bag for bulk materials according to claim 3, characterized in that

6. The valve (50) is formed as at least one of a valve tube (50) and a valve patch (52).

4. A bag for bulk materials according to claim 3, characterized in that

7. having two opposing bottoms; Side walls (16) extend between the two opposing bottoms.

3. A bag for bulk materials according to claim 1 or 2, characterized in that it is

8. The bag is designed as an open cross bottom or block bottom bag.

3. A bag for bulk materials according to claim 1 or 2, characterized in that it is

9. The bag is designed as a multi-layer bag, The material layer is at least one of paper, coated paper, and plastic.

3. A bag for bulk materials according to claim 1 or 2, characterized in that it is

10. The bag is formed from three layers, the innermost and outermost layers of material being formed from paper; The intermediate material layer is formed from a plastic film.

3. A bag for bulk materials according to claim 1 or 2, characterized in that it is

11. The bag is made of compostable and / or recyclable materials, in particular paper and / or coated paper.

3. A bag for bulk materials according to claim 1 or 2, characterized in that it is

12. At least one of the bottoms includes at least one of an inner latch (40) and a cover sheet (45).

3. A bag for bulk materials according to claim 1 or 2, characterized in that it is

13. The inner latch comprises at least one of uncoated paper, PE coated paper, and film.

13. A bag for bulk materials according to claim 12, characterized in that

14. The bag is formed from a piece of tubing having a smooth break at at least one end, preferably at both ends (13, 14).

3. A bag for bulk materials according to claim 1 or 2, characterized in that it is

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