Patent Application
20170334608
The invention described and claimed hereinbelow is also described in European Patent Application EP 16 170 007.5, filed on May 17, 2016. The European Patent Application, the subject matter of which is incorporated herein by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d).
The invention relates to a method for producing a side-gusseted bag. The method includes guiding a material web of a bag film in a production direction, and folding the bag film to yield a side-gusseted tube comprising a first front wall, a second front wall, and, disposed therebetween, side gussets which connect the front walls. Individual side-gusseted bags are separated from the side-gusseted tube. The invention also relates to a flat, unfilled side-gusseted bag formed using the method.
Side-gusseted bags and methods for the production thereof are known from EP 1 620 321 B1, EP 1 948 527 B1, EP 2 032 454 B1 and EP 2 148 820 B1. Such side-gusseted bags known from this prior art comprise a reclosure having a single, self-interlockable reclosure strip which extends on the bag inner side on one side gusset and, adjacent to the side gusset, also extends on the two front walls, and which connects the side gusset to the two front walls. Proceeding from a center line of the side gusset, a wing, i.e., one half of the corresponding side gusset, is connected to the first front wall and the other half of the side gusset is connected to the second front wall. According to the prior art and within the scope of the invention, the length of the reclosure strip can be different on the two front walls. In particular, the reclosure strip on the front walls can also extend beyond the corresponding side gussets, and therefore the two front walls are directly connected to each other adjacent to the side gusset, whereby a larger removal opening is provided. It is always provided, however, that the reclosure extends only across a portion of the entire width of the front walls. Advantageously, a connecting line a heat-sealed seam, can be also provided alongside the reclosure strip either in the bag longitudinal direction or the bag transverse direction, to delimit the opening.
Different methods are known in practice for producing side-gusseted bags. For example, the front walls and the side gussets are formed from a single film web by folding. Individual side-gusseted bags or corresponding blanks are then separated from one side-gusseted tube comprising the front walls and the side gussets, each of which comprises a reclosure device.
Since the production direction of the material web or the side-gusseted tube corresponds to the longitudinal direction of the side gussets, the corresponding methods are also referred to as “longitudinal methods.”
Individual side-gusseted bags are then separated from the side-gusseted tube, wherein a filling can take place directly at the same time, wherein this is then a so-called FFS method (form-fill-seal method). Alternatively, pre-made side-gusseted bags can also be initially formed, which are not yet closed on at least one side and can then be initially stored and brought to a packaging site. Such side-gusseted bags are then filled and closed separately.
Alternative production methods are also known from practice, in the case of which the front walls and the side gussets are formed from separate film sections. For example, EP 1 541 332 A1 describes a method for producing film packaging bags, in the case of which a bag strand is formed in such a way that successive film packaging bags are arranged next to each other at their bag longitudinal edges. The production direction therefore corresponds to a bag transverse direction of the individual bags, and such a method is therefore also referred to as a transverse method or a Totani method.
According to EP 1 541 332 A1, a bag strand is initially formed from successive, connected bag blanks. A first film web is guided in the production direction. A film strip is then supplied, wherein the edges of the film strip are folded over onto a center section. The edges are usually equally wide, wherein a gap remains between the edges after folding. Subsequently, pieces of the film strips are placed onto the first film web at equidistant intervals, transversely to the production direction (i.e., along the bag longitudinal direction), before a second film web is supplied in the production direction, which then covers the first film web and the pieces of the film strip. Longitudinal sealing seams are then produced transversely to the production direction, by which the film strips are bonded to the second film web at the folded-over edges, and to the first film web on an opposite side. Next, individual film packaging bags are separated from the bag strand, which has been formed in this way, by a cut in the region of the film strips in such a way that two side gussets of successive side-gusseted bags are formed from one folded film strip. In addition to the side gussets, a separate bottom gusset also can be produced as a flat base.
In the case of such a transverse method, it is readily possible to design the side gussets to be shorter than the two front walls, and therefore one continuous reclosure, which only connects the two front walls to each other, can be situated above the side gussets. The arrangement of a reclosure in the region of one of the side gussets, by which the corresponding side gussets can be folded outward as a spout, is not advantageous in the case of the described transverse method, however, because separate film pieces must be supplied and subsequently connected in order to form the two front walls and the side gussets, wherein the integration of a reclosure on one of the side gussets and the assigned sections of the front walls is not possible using usual technical means.
To produce a base in the case of the known method for producing a side-gusseted bag of the type in question, one lower edge of the side-gusseted bag can be closed by a transverse sealing seam, wherein an even upright stance of the side-gusseted bag is not possible. Instead, such a side-gusseted bag tends to tip over during filling, transport, and storage, when said bag is supposed to be stood upright on its lower section, as the base.
To reduce this tendency to tip over, it is known to initially close a lower section of the side-gusseted bag by means of a transverse sealing seam and to then fold said lower section onto itself, whereby a type of reinforced double-walled base is formed. This method is disadvantageous, however, in that one further working step for the folding-over is necessary, wherein an increased demand for material also results due to the folding of the lower section onto itself. Finally, a certain asymmetry remains in one direction due to the folding-over of the end section, and therefore a tilted position cannot be completely avoided. The additional generation of corner sealings or the like also cannot completely solve the problem described.
The present invention overcomes the shortcomings of known arts, such as those mentioned above.
The present invention provides a method for producing a side-gusseted bag that displays a good standing ability and a high-quality appearance. The method also produces a flat, unfilled side-gusseted bag comprising a reclosure device.
In an embodiment, the method for producing a side-gusseted bag includes that an incision extending in a transverse direction is produced in the bag film for each side-gusseted bag in such a way that, in the case of the side-gusseted tube, the incision extends over both side gussets and the first front wall which is situated between the side gussets. In the case of the side-gusseted tube, the first front wall, which is parted by means of the incision, is lifted on one side of the incision and is at least partially folded over, whereby sections of the underlying second front wall and the side gussets are exposed.
To form a flat base, a separate film section is connected via first connecting seams to the folded-over section of the first front wall and the second front wall and via second connecting seams to the exposed side gussets, and the folded-over section is folded back in such a way that the second connecting seams extend in parallel to the first connecting seams in the transverse direction.
The side-gusseted bag is usually formed from plastic film, for example, multilayer laminated films are considered for the production, wherein the films in this case comprise a heat-sealable inner layer on an inner side of the side-gusseted bag and an outer layer forming the outer surface of the side-gusseted bag, wherein, in the case of a laminated film, an imprint can also be provided on the inside, which is produced before the laminating is carried out.
In an embodiment, one of the two side gussets can be provided with the reclosure device, by which the side gussets can be fixed and closed in a folded-in state between the front walls, the side gussets can be folded outward by opening the reclosure device, to form a spout. In the case of a filled side-gusseted bag, a top sealing seam extending in the transverse direction is usually provided above the reclosure device, which seam must be initially torn off, cut off, or peeled open, in areas, to facilitate a first-time opening which is accompanied by a removal of the top section.
The side-gusseted bag is usually provided with printing on the bag outer side on all bag surfaces, i.e., on its front walls, its side gussets, and on the separate film section as the base, or is provided with an imprint on the inside, which is visible on the outside of the bag. The inner surfaces of the side-gusseted bag, however, are formed of a sealable layer which is usually designed to be a single color, in particular white.
With respect to the arrangement of the separate film section, it should be noted that regions of the film section can extend beyond the underlying surfaces of the front walls and side gussets, or can fall short of the surfaces, due to a deviation in terms of size and position. In the absence of further measures, this would result in the case with respect to the finished side-gusseted bag in which sections of the inner surfaces of the bag are visible as so-called “fringe”, whereby the visual appearance of the side-gusseted bag is substantially adversely affected.
To avoid such fringe, within the scope of the invention, the film section and the lower edges of the front walls and side gussets are trimmed, wherein this trimming preferably takes place simultaneously with the separation of individual side-gusseted bags from the side-gusseted tube.
In this context, the method according to the invention is carried out in such a way that, when the previously folded-over section is folded back, the second connecting seams, by which the separate film section is connected to the side gussets, extend in parallel to the first connecting seams in the transverse direction, for which the folding-back must be controlled in a suitable way. In the case of a folding-back along a straight line, the separate film section would extend along the first connecting seams in the transverse direction and along the second connecting seams in the longitudinal direction of the side-gusseted tube, for which a trimming would therefore also be necessary to avoid “fringe” both in the transverse direction and in the longitudinal direction of the side-gusseted tube.
According to the invention, the folding-back is carried out and controlled in such a way, however, that the side gussets are re-inserted between the front walls along their entire length, whereby the separate film section is then placed in multiple layers, one over the other, in the region of the side gussets, and therefore the lower end of the side gussets then overlaps with the lower ends of the front walls again, and therefore the first connecting seams and the second connecting seams also can be jointly trimmed here as well by a single cut in the transverse direction. Also, a double cut along two cutting lines extending in the transverse direction is carried out to trim and separate the individual side-gusseted bags. Underneath the separate film section provided as the base, a first cutting line of the double cut forms the upper edge of the subsequent bag. By the second cut of the double cut, so much material is removed in the region of the separate film section that the above-described “fringe” also is completely removed in the event of dimensional and positional deviations.
The distance between the two cutting lines of the double cut can be, for example, between 1 mm and 20 mm, in particular, between 2 mm and 10 mm. The incisions can be advantageously formed in the material web when it is still flat, wherein tearing must be prevented during folding, however, and the material web must be guided with appropriate caution. In a variation, only one line of weakness or a perforation is provided on the material web, which is subsequently further separated.
In an embodiment, the method provides that reclosure strips extending transversely to the production direction are arranged on the material web with uniform spacing and equidistantly from the incisions; after the formation of the side-gusseted tube, the reclosure strips extend on one of the side gussets and over a portion of each of the two front walls. Such side-gusseted bag, which is described in the following, is formed with a reclosure on the first side gusset.
The reclosure strip extends on the front walls advantageously at least across a width which corresponds to half the width of the assigned side gusset. In such an arrangement, only one connection of the two wings of the side gusset to one of the front walls, respectively, is established. If the reclosure extends beyond the region of the side gussets, sections of the two front walls also can be directly connected to each other. At the least, the reclosure strip extends over only a portion of the front walls.
According to one further aspect of the invention, handles, which are advantageously located on the side gusset that is positioned opposite the reclosure strip, also can be installed in the method. Usually precisely one handle and precisely one reclosure strip are fastened for each bag. While the reclosure strips are fastened on the inner layer of the bag film, the handle must also be accessible from the outside. Different suitable handle configurations are known from EP 2 148 820 B1.
To close the side-gusseted bag around the circumference, a heat-sealed seam is provided. The heat-sealed seam is formed in the region of one of the lateral edges. Preferably, all lateral edges are provided with a heat-sealed seam to improve the stability of the side-gusseted bag, which is formed. If the material web is bonded at one lateral edge to form a tube that is closed around the circumference, overhangs can also be provided there, which are trimmed, i.e., cut off.
The first front wall is preferably folded over on a fold line, which is spaced apart from the incision, in such a way that the distance of the fold line to the incision corresponds to approximately one-half the width of the side gusset. The front wall is then folded over as far as possible, whereby the exposed side gusset extends outwardly at an oblique angle of 45°, proceeding from a central bending line.
The separate film section for forming a flat base for each side-gusseted bag is advantageously fastened to the front walls and to the side gussets by heat-sealed seams. The sealing at the side gussets can readily take place on the flat side-gusseted tube. The same applies for the connection of the separate film section to the exposed second front wall. To avoid an undesired sealing within the side-gusseted tube during the connection of the separate film section to the folded-up edge of the first front wall, the corresponding generation of a transverse sealing seam preferably takes place in the lifted state.
The invention also provides a flat, unfilled side-gusseted bag comprising two front walls positioned opposite each other, and a first and a second side gusset which are positioned opposite each other, extend along a bag longitudinal direction, and each connect the two front walls to each other. Preferably, at least one reclosure device comprising a reclosure strip is provided, the reclosure device being situated in the region of the first side gusset that extends along a bag transverse direction across only a portion of the width of the front walls and allows the first side gusset to be folded outward to form a reclosable spout. The flat, unfilled side-gusseted bag can be produced, in particular, using the above-described production method and is characterized in that a separate film section is provided for forming a flat base. The film section is connected via first heat-sealed seams to lower ends of the front walls and via second heat-sealed seams to lower ends of the side gussets, wherein the film section is situated between the front walls in such a way that the first heat-sealed seams and the second heat-sealed seams are arranged in parallel to each other along the bag transverse direction.
Due to this arrangement, it is possible, during the formation of the flat, unfilled side-gusseted bag, to trim all edges of the separate film section or the parts of the front walls and the side gussets connected thereto by one single cut extending in the bag transverse direction, to eliminate any overhangs and “fringe” generated thereby.
By providing a reclosure on one side gusset and forming an outwardly foldable spout, on the one hand, and providing a flat base in the form of a separate film section, on the other hand, particularly advantageous measures are combined, according to the invention.
The side-gusseted bag according to the invention is characterized by particularly advantageous handling. With the aid of the reclosure device on the first side gusset, the side gusset can be fixed in a folded-in state after a first-time opening. The two wings of the first side gusset are each then fastened on one of the two front walls. The side gussets then can be folded outward by releasing the reclosure, to form a spout, thereby making it possible to measure out particularly easily and precisely. In particular, the side-gusseted bag can be emptied by a user in a controlled manner by a tilted position, wherein, specifically, a precise removal of partial quantities is possible and the remaining product is protected by the reclosure device.
The side-gusseted bag can have a fill volume between 1 l and 50 l, in particular, between 20 l and 30 l. The side-gusseted bag is suitable, in particular, for accommodating pourable product such as pelleted animal food, detergent, cat litter, de-icing salt, and powdered or granular building materials.
To ensure a reliable closure, a top sealing seam, which sealingly closes the side-gusseted bag, is, provided above the reclosure device for a first-time opening. For a first-time opening, at least one part of the top of the bag formed by a top sealing seam is torn off, to expose the underlying reclosure device and make it possible to fold out the spout.
The reclosure device comprises at least one reclosure strip, which preferably extends precisely in the bag transverse direction. The reclosure device may comprise several separate reclosure strips that can be interlocked with, each other. In an embodiment, however, the reclosure device comprises a single, continuous and self-interlockable reclosure strip. Such a reclosure strip can be placed onto a flat material web particularly easily during production, wherein this reclosure strip is then situated in the desired position on the side gusset merely by folding.
With respect to the specific embodiment of the reclosure strip, different possibilities result within the scope of the invention. Even though a reclosure strip based on adhesive is not ruled out, a mechanical interlocking preferably takes place. To achieve a mechanical interlocking, the reclosure strip can comprise either continuous closure formations or a large number of individual closure elements that can be interlocked with each other. Possible continuous closure formations are, for example, grooves, projections and strips bent into the shape of hooks, which can be interlocked′ with each other or are self-interlockable. Corresponding structures can be extruded as a strand, for example, wherein the closure formations are usually arranged on a heat-sealable support section or are integrally extruded with the heat-sealable support section.
Individual closure elements that can be interlocked with each other can be provided, for example, in the form of gripping hooks, mushrooms, or the like. Individual closure elements that can be interlocked with each other yield the advantage that a secure interlocking is possible even in the case of a vertical offset. The individual mushrooms or gripping hooks are generally movable in such a way that, when pressed upon from the outside, they can enter an assigned space and interlock with similar closure elements therein. In the case of individual closure elements that can be interlocked with each other, the advantage also results that, although soiling locally prevents a connection, the entire reclosure strip cannot be easily pulled off proceeding from the soiling.
According to an embodiment, the front walls and the side gussets are formed from a bag film, in particular a uniform bag film. The front walls and the side gussets are folded from a uniform material web, as described above. The bag film comprises at least one heat-sealable inner layer and one outer layer, wherein the assignment to the inner layer and the outer layer is relative to the arrangement of the bag film on the side-gusseted bag. The inner layer therefore forms the inner surface of the side-gusseted bag, while the outer layer forms the outer surface.
The inner layer is advantageously well heat-sealed in order close the bag around the circumference, enable the formation of longitudinal and transverse sealing seams, and enable further devices such as the reclosure device to be fastened by heat sealing. Possible heat-sealable materials for the inner layer are not only polyolefins such as polyethylene (PE) and polypropylene (PP) and copolymers of polyolefin, but also different biologically degradable plastics such as polylactic acid (PLA), polybutylene adipate terephthalate (PEAT), and polybutylene succinate (PBS).
The outer layer cannot be heat-sealed as well as the inner layer, for which the outer layer can have a higher melting or softening temperature. As a result of a heat-sealing of the bag film, although the inner layer is melted, possibly through the outer layer, the outer layer is not excessively deformed, nor does it lose its structure. The outer layer can be formed from polyester, in particular. A reduction of the melting tendency during heat sealing is achieved by an orientation of the outer layer. Possible materials for the outer layer are therefore also oriented polyethylene terephthalate (OPET), oriented polyamide (OPA), oriented polypropylene (OPP), and oriented polylactic acid (OPLA). In addition, the outer layer can be formed from a cellulose film.
According to an embodiment, a laminated film is utilized as the bag film, wherein a first film is connected to the inner layer by adhesive and at least one second film is connected to the outer layer by adhesive. A two-component adhesive based on polyurethane (2K-PUR), for example, is suitable. Finally, further intermediate layers can be provided, for example, to increase the barrier effect. A film layer made of ethylene vinyl alcohol copolymer (EVOH), a thin metal foil, or a metallized film layer, for example, can be provided as barriers.
In the case of a laminated film, an imprint is preferably also provided on the inside, which is applied to one of the connecting surfaces of the films to be connected to each other, before the laminating is carried out.
As described above, the side-gusseted bag is advantageously produced using a longitudinal method, wherein a material web of the bag film is initially reshaped into a side-gusseted tube, from which individual side-gusseted bags are then separated. Correspondingly, according to an embodiment, at least a portion of lateral edges formed between the side gussets and front walls is designed as folded edges. A longitudinal sealing is advantageously carried out to allow for closure around the circumference during the production of the side-gusseted tube. The longitudinal sealing can coincide with one of the lateral edges, and therefore this lateral edge is not designed as a folded edge. In addition, the edges of the material web also can be connected to one of the front surfaces by a longitudinal seam.
Even if at least one portion of the lateral edges is designed as folded edges, the generation of longitudinal sealing seams on the lateral edges is advantageous to increase the dimensional stability and dimensional accuracy of the side-gusseted bag. After the formation of longitudinal sealing seams, an outer edge can also be cut off to improve the appearance.
An upper bag edge above the reclosure device is usually closed by a transverse sealing seam. Within the scope of such an embodiment, it is preferably provided that the side gussets extend from the flat base up to the transverse sealing seam on the upper edge of the bag, i.e., across the entire side-gusseted bag as viewed in the bag longitudinal direction. Further measures for shortening the side gussets are then unnecessary.
In the case of a large filling volume and/or a high filling weight, in particular, the side-gusseted bag can be provided with a handle. The handle can be punched at the top of the bag, in a sealed region, as is known from EP 2 032 454 B1. According to one preferred embodiment of the invention, however, the second side gusset comprises a handle which is then positioned opposite the reclosure device. Suitable embodiments of handles are known from EP 2 148 820 B1. While the reclosure device is advantageously situated close to an upper end of the side-gusseted bag, the handle can be located, with respect to the bag longitudinal direction, approximately in the center or slightly offset in the direction of the flat base of the side-gusseted bag. Accordingly, the weight of the side-gusseted bag is then easily controlled even during pouring.
The flat base provided by a separate film section according to the invention comprises a heat-sealable inner layer and an outer layer, as described above, wherein the flat base also can be formed from the above-described bag film. The flat bottom usually has a rectangular shape, wherein the length and width of the film section correspond to the width of the front walls and the width of the side gussets, respectively.
Due to the flat bottom, the side-gusseted bag can stand upright. This is equally advantageous during the filling, transport, storage, and handling of the side-gusseted bag. In contrast to a tube section, which has simply been folded over to form a standing base, not only is handling improved, but also material is saved, because there is no need to arrange several film layers one above the other.
Further features and advantages of the invention will become apparent from the description of embodiments that follows, with reference to the attached figures, wherein:
The following is a detailed description of example embodiments of the invention depicted in the accompanying drawings. The example embodiments are presented in such detail as to clearly communicate the invention and are designed to make such embodiments obvious to a person of ordinary skill in the art. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention, as defined by the appended claims.
While
It should be apparent from
For opening the side-gusseted bag for the first time, a line of weakness 7 is situated above the reclosure strip 6, by which a corner section 8 above the reclosure strip 6 can be removed. The line of weakness 7 can be formed, for example, by a punching, a perforation, or a laser, wherein the different measures can also be combined with one another. A notch 9 also is provided for initiating the tear.
To provide for a sufficient closure of the side-gusseted bag after a first-time opening, a transverse sealing seam 10, which extends from the end of the reclosure strip 6 to the opposite bag edge, is formed adjacent to the reclosure strip 6.
After a first-time opening, the first side gusset 2a can be folded outward by opening the reclosure device formed by the reclosure strip 6, thereby forming a spout, and can be re-inserted between the two front walls 1a, 1b, to permit closure again. According to the invention, the side-gusseted bag comprises a flat base, which is formed from a separate film section 11. The film section 11 is connected to the lower edges of the front walls 1a, 1b, and the side gussets 2a, 2b, by heat-sealed seams 12a, 12b. While the flat base is particularly advantageous for filling, transport, storage, and handling, and makes it possible to reliably stand the side-gusseted bag upright, the product can be easily removed by the reclosure device, wherein the removal of partial quantities, in particular, is also precisely possible due to the formation of a spout. Depending on the filling weight, the side-gusseted bag can also be equipped with a handle (not shown), which is advantageously located on the second side gusset 2b positioned opposite the reclosure device.
The reclosure strip 6 can comprise continuous closure formations in the form of grooves or projections or also a large number of individual closure elements that can be interlocked with each other, wherein such individual closure elements that can be interlocked with each other can have the shape, for example, of mushrooms or gripping hooks.
It should be apparent from
A preferred method for producing the side-gusseted bag shown in
In the method, a material web of a bag film 13 is fed in a production direction p, the orientation of which corresponds to the bag longitudinal direction l. The corresponding method, therefore, also is referred to as a longitudinal method.
According to
Further according to
Alternatively, in a modification of the step depicted in
The bag film 13 is formed of at least two layers and comprises a heat-sealable inner layer made of polyolefin, in particular, polyethylene, and an outer layer made of polyester, in particular, polyethylene terephthalate (PET). The film section 11 can be formed from an identical or similar material having a corresponding layered design. According to
Since the incisions 16 extend across the first front wall 1a and both side gussets 2a, 2b, the first front wall 1a can be lifted, for which grippers or vacuum cups, for example, can be utilized.
In
According to the exemplary embodiment depicted in
Based on
To avoid the undesired production of a heat-sealed seam within the side-gusseted tube 14 during the connection of the separate film section 11 to the first front wall 1a, it can be provided according to
As represented in
In this context, it is indicated in
As will be evident to persons skilled in the art, the foregoing detailed description and figures are presented as examples of the invention, and that variations are contemplated that do not depart from the fair scope of the teachings and descriptions set forth in this disclosure. The foregoing is not intended to limit what has been invented, except to the extent that the following claims so limit that.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16 170 007.5 | May 2016 | EP | regional |
