EP3114038A1 - Paper bag and production method for a paper bag - Google Patents

Abstract

The invention relates to a paper bag (10) for bulk goods such as cement, gypsum, granular material, animal feed, or the like, comprising a bottom (2) and an upper part (3) opposite the bottom, wherein, by adding the side parts (5), the bottom and/or the upper part is folded around side folding lines (4) and glued, in particular in the form of a rose bottom or block bottom, wherein at least one glue or adhesive (11) that can be activated after the application is provided for gluing the side parts, which at least one glue or adhesive is applied continuously at least from one side folding line (4) to at least the opposite side folding line (4) of the side parts.

Description

 Paper bag and method for producing a paper bag

The invention relates to a paper bag for particular fine-grained bulk material, such as cement, gypsum, granules, animal feed or the like, with a bottom and a top opposite the bottom, wherein the bottom and / or top are folded by adding the side panels to Seitenfalzlinien and glued, in particular in the form of a cross or block floor. Another aspect of the invention relates to a special manufacturing method for such a paper bag.

Generic paper sacks are known, for example from EP 1 858 769 B1. In particular, the usual sizes are 5 kilos, 10 kilos or 25 kilos distributed in the trade. They have one or more paper layers which are formed from paper or a paper composite and / or coated paper. It is also possible for layers of other materials to be present, for example a plastic film, as in the case of EP 1 858 769 B1.

Such paper bags are usually made of continuous paper webs, the longitudinal edges are glued like a tube. To form the bags, the tube is cut into sections of suitable length and at the open ends the tube sections are folded and glued bottom and top to close the paper bag ground and / or head side. Usually, a cross or block bottom fold is selected here, wherein as a rule a scoring or the like is carried out to facilitate the folding in the region of the fold lines. The folding parts are glued by means of a glue, usually a starch-water mixture. For manufacturing reasons, however, the glue used must be left out in the region of the fold lines. This restriction is due to the fact that the glue in the region of the fold lines or in the edge region would lead to contamination of the production machine for paper bag production and thus a continuous production of the paper sacks would not be possible. In particular, when applying a grooving in the region of the fold lines an existing in this area glue application would lead to a strong contamination of the tools used in the machine for grooving. In addition, during the application of the starch glue pattern, a certain minimum distance from the edges or side edges of the bottom / top part must be maintained, since otherwise also a contamination and adhesion of certain machine parts threatens.

However, the glue recess leaves a non-bonded area along the score lines and edges / margins in the bottom and / or top of the paper bag. This can create channels that allow the exit of the dust-like filling material even after closing the bag.

Furthermore, the laying of the bottom / top causes a certain amount of paper, causing curls of the paper and wrinkles and displacements in the region of the abutting edges of the bottom center, also called bottom center line, arise. These waves, wrinkles and edges can not be fully adhered to the starch glue, as it does not penetrate completely and does not extend to the folded edge. This requires an additional channel formation in addition to the channels of the folding lines, which increase the discharge amount of the filling material. The present invention therefore addresses the problem of providing dustproof paper bags.

This object is achieved by a paper bag according to the features of claim 1 and by a manufacturing method according to the features of claim 10. Advantageous embodiments of the paper bag and the method are the subject of the dependent claims adjoining the respective independent claims.

The invention is based on a generic paper bag with the features of the preamble of claim 1. According to the invention, at least one adhesive or adhesive agent which can be activated after application is provided for bonding the side parts, the application surface of which runs continuously at least from one side fold line to at least the opposite side fold line of the side parts. Essential to the invention is the application of a continuous adhesive or adhesive trace from a Seitenfalzlinie to the opposite Seitenfalzlinie, the surface shape, strength is arbitrary, which turns out to be preferable a strip shape.

It is also critical that the application begins directly within the side fold lines and extends to at least the opposite side fold line. For a continuous bonding when folding the paper bag is achieved and the aforementioned adverse channeling can be effectively prevented. The subsequent activation allows the application at the beginning of the manufacturing process. In the deactivated state, there is thus no danger that individual machines will become dirty during the subsequent production process. Activation preferably takes place only immediately before the final collapsing of the paper bag. Therefore, individual fold lines and edge areas do not need to be recessed - as known from the use of a starch glue - but can be completely provided with the adhesive. As Seitenfalzlinien are those fold lines understood by the side flaps are added. In the case of the cross and block bottom folding, the two side flap fold lines are finally folded so that these fold lines lead to the outside of the bag. At the outer areas of the Seitenklappenfalzlinien are the Endinschläge, which are formed at the cross bottom as outwardly pointed corner strokes and the block bottom as trapezoidal impacts. The side panels are folded inwardly about the side fold lines to bond them to the end panels and / or each other by means of the adhesive or adhesive.

Advantageously, in each end region of the side-fold lines, i. provided in the region of the two end impacts, at least one continuous adhesive or adhesive surface. Overall, at least two, preferably four continuous application surfaces of the adhesive or adhesive can be provided both on the bottom part and on the upper part. If an integration of a valve for filling the paper bag is provided, can be dispensed with the application of adhesive or adhesive in the region of the valve tube.

Preferably, at least one adhesive surface extends between the end regions of the respective side-fold lines, in particular transversely to the bottom centerline, which lies between the respective side-fold lines and is intended to be closed by the combination of the side parts.

It is also conceivable that the applied adhesive or adhesive surface extends beyond at least one of the Seitenfalzlinien, preferably to immediately to the edge of the Endinschläge or beyond on the back.

It is also preferable to apply a plurality of strip-like and parallel adhesive and / or adhesive surfaces, preferably at least two parallel strips are provided in the region of each end of the upper part and / or bottom. In addition, it is additionally possible to provide a non-continuous adhesive or adhesive surface or strip, the partial sections of which fall at least on the side-fold lines and / or the center-fold line. The application of such an adhesive pattern of at least two parallel adhesive or adhesive strips, ideally in combination with a non-continuous adhesive or adhesive strip, is particularly advantageous if a different type of adhesive is additionally used for bonding the side parts. The adhesive surfaces with different types of adhesive can overlap or be arranged separately next to one another.

Preferably, for firm and stable bonding of the bottom and / or top or their folded parts additionally glued with a separately applied, possibly different type glue, especially based on a starch-water mixture, said glue not in the region of the fold lines and not in the edge region of the side parts or strikes is applied, so the glue order spares these areas. Particularly advantageous is the application of the adhesive and / or adhesive according to the invention in areas adjacent to the glue application. Ideal is an alternating application of the glue and the adhesive and / or adhesive used in the folding direction. For example, in the fold line direction adjacent areas of the side parts are glued alternately with the starch glue or the adhesive or adhesive with the impacts. This procedure makes it possible to exploit the advantages of both types of adhesive in every relevant area of the bond. Bonding with starch glue on paper ensures a particularly good and mechanical firm bond, since good adhesion of the glued paper layers is achieved and the bond penetrates particularly deeply into the paper. By contrast, the bonding with the adhesive or adhesive used is not so strong, but due to the application across the surface to the bottom finish, it ensures a completely adhesive bond, thereby avoiding the disadvantageous formation of channels or closing the resulting channels of starch adhesive bonding. A wet rubber or so-called envelope glue which can be activated by liquid or steam addition, in particular water or steam, is preferably used as the adhesive. This feature has the advantage that the adhesive, ie the wet rubber or the envelope glue, can be deactivated after application to the paper bag, for example by drying, in order to avoid soiling of the production machines during production. Immediately before or after folding, the adhesive can then be activated.

As a bonding agent, for example, a sealing compound, preferably a cold seal mass are used, which is activated upon compression of provided with the sealing compound surfaces and then acts as an adhesive. An application of liquid or steam is not necessary in this case. Also conceivable is the use of a hot melt adhesive, which is deactivated by cooling and can be reactivated with subsequent heat supply.

In a preferred embodiment of the invention, at least one film for closing the paper bag by means of the adhesive and / or adhesive and / or the applied glue with the side panels and / or the Endinschläge be glued. The introduction of such a film, also referred to as an inner bar, in particular a water and dust-tight film, serves to realize a particularly preferred closure of the paper bag. The actual dust-tight bag closure is therefore no longer due to the folding of the side parts, but only by the application of the film. For transport purposes, however, the side parts are preferably combined and bonded as known.

The inner bar-forming film may preferably be formed from paper and / or coated paper and / or plastic and / or a metal foil. The inner bar can cover the applied adhesive and / or adhesive agent surface either partially or completely. In the partial cover, the excess adhesive or adhesive area can serve for the bonding of the side parts. 00640

 7

In addition to the paper bag according to the invention, the invention relates to a method for producing the paper bag according to the invention with a folded bottom and / or top. According to the invention, an adhesive and / or adhesive is applied to a paper roll or paper web for producing the paper sacks and / or printed prior to folding the bottom or the upper part. The application of the adhesive and / or adhesive takes place in such a way that an inventive paper bag according to the present invention or an advantageous embodiment of the invention results. Only after applying the adhesive and / or adhesive surface on the paper roll or paper web, the paper bag is then folded in the floor and glued, the activation of the adhesive and / or adhesive used only immediately before or during collapsing or gluing the side panels he follows.

Furthermore, a water-starch mixture is preferably applied in the floor layer, so that a gluing area with alternating adhesive / adhesive and starch glue surfaces is produced, in particular alternately in the direction of the side folding or bottom center lines.

The activation of the pre-applied adhesive in the bottom layer can be activated by the addition of water and / or water vapor according to a preferred embodiment of the method. When using a water-starch mixture for bonding the side parts, it is expedient to simultaneously activate the applied adhesive in the bottom layer by this addition of water. Additionally or alternatively, a steam addition can also be effected by means of a pressure nozzle.

In an optional method step, at least one inner bar for airtight bag closure by means of the applied adhesive and / or adhesive and / or the starch-water mixture can be adhered to the folded but still unfolded bottom and / or top section. The application of the adhesive and / or adhesive to the paper web or paper roll is preferably carried out via a printing cylinder, which prints the desired surface shape in terms of the clock, so that the adhesive or adhesive pattern according to the invention results. The application of this adhesive and / or adhesive is advantageously carried out using a flexographic printing machine.

The size and shape of the application surface and the application thickness of the adhesive can be made variable, for example, depending on the materials used and / or the production facility and / or the intended intended use of the produced paper bag, i. depending on the desired contents.

In a preferred embodiment of the invention, the selected adhesive or adhesive is deactivated after application for subsequent grooving or otherwise processing the fold lines during the process, for example by active or passive drying of the applied adhesive, so that subsequently for the grooving or other processing used machine parts or tools are not polluted by the existing adhesive in this area. After this grooving or processing, i. If no machine parts or tools come into contact with the fold lines, the adhesive can be activated. In another preferred embodiment of the invention can be used as an adhesive and a hot melt adhesive, which can be activated by heat. Particularly preferably, the hot melt adhesive is applied warm or hot to the paper sack and deactivated after the first application in ways of cooling. Later, then for the addition or closing of the bottom or upper part, the activation of the hot melt adhesive by heat.

If a sealing compound, in particular cold sealant is preferably used, the adhesive effect can be activated by pressing together surfaces which are covered with the cold sealant. For this purpose, the cold sealant is not only applied between the Seitenfalzlinien, but also on the To apply areas of the side parts, which is pressed onto the corresponding surface between the fold lines.

Further advantages and features of the invention are explained in more detail below with reference to an embodiment shown in the drawings.

Show it:

FIG. 1 shows a schematic plan view of a paper bag according to the invention with base and upper part,

Figure 2: a plan view of the open bottom of a paper bag according to the

 State of the art,

FIG. 3 is a plan view of the open bottom of the paper bag according to the invention;

Figure 4: a schematic representation of a section of a paper web for

 Production of a paper bag according to the invention,

Figure 5: another plan view of the paper bag according to the invention with open bottom and

Figure 6: a plan view of the closed bottom of the invention

 Paper bag.

FIG. 1 shows the paper bag 10 according to the invention with a cross bottom 2 and a top part 3, the bottom 2 and the top part 3 being folded on the front side 9 of the paper bag 10. Not recognizable is the back of the bag 10, which lies under the front side 9. In the upper part 3, a valve tube 50 is used to fill the paper bag 10. The paper bag may comprise two or more layers of paper or material. The concrete embodiment of the paper bag 10, that is, the number of used paper or material layers is irrelevant to the implementation of the invention, which is why not discussed in detail. In the upper part of a known per se valve 50 may be provided for filling the bag.

To illustrate the advantages of the present invention, initially an open partially folded bottom part 2 of a conventional paper bag 1 is considered, which is shown in FIG. To see a detail of the sack bottom 2 of the conventional paper bag 1 with cross bottom. In the figure 2, the cross bottom 2, however, is not folded, but the side flaps 5 are opened and the corner impacts 6 recognizable. For the folding of the cross base both side flaps 5 are folded inwards in the direction of arrow 7 and that along the respective Seitenklappenfalzlinien 4, which are provided with a Bodenrillung.

For gluing the crosshead, i. the two side flaps 5, a glue 8 of a starch-water mixture is applied areally on the corresponding surfaces in order to glue the upper side flap 5 with the Eckeinschlägen 6 and the lower side flap 5 with the surface of the already folded side flap 5. Furthermore, it can be seen in FIG. 2 that the glue 8 is cut out in the area of the grooved upper and lower side flap fold lines 5 and this area thus remains without glue. The same applies to the edge regions of the corner impacts 6 and the side flaps 5, the outer edge remains completely free of glue.

This recess has the technical background that during production, in particular when creating the Bodenrillung along the creasing lines 4, no glue on the necessary production tools may get to it or in an application of the glue in the edge region it would come to contamination of underlying machine parts. Because of the recess in the glue 8 along the fold lines 4 and in the edge region, however, an air and dust-permeable channel from which contents from the bag interior via the marking in Figure 6 arises adversely ¹ Reinforcing the channel formation is characterized in that when folding the bottom of a compression of the paper occurs, which in addition to a corrugation of the paper as well as wrinkling and displacement in the region of the abutting edges the ground centerline 4 "is coming. These waves and wrinkles and edges can not be fully adhered to the starch glue 8, as this does not penetrate completely and does not reach to the folded edge.

The inventive approach is illustrated in FIG. The illustration likewise shows a detail of an open, partially folded cross base 2 of the paper bag 10 according to the invention. The features of the cross base 2 which are identical to those of the prior art are provided with identical reference numerals. The wet rubber lining 11 according to the invention is applied continuously between the two side fold lines 4 of the side parts 5. In particular, the prominent locations in the area of the side fold lines 4, the incisions 4 'and possible paper folds are airtight closed especially in the area of the bottom center 4 ", so that leakage of the contents is prevented when the paper bag 10 is closed.

In the illustration according to FIG. 3, it can also be seen that the wet rubber coating 11 is applied in a special adhesive pattern to the corner impacts 6 of the base 2. In particular, two parallel continuous adhesive strips 11 'and an interrupted adhesive strip 11 "extend from one side fold line 4 to the opposite side fold line 4. At the end, the adhesive strips 11', 11" are connected to each other via a full-surface adhesive surface 11 "'.

This advantageous arrangement of the adhesive surface 11 serves to achieve an alternating application of activatable adhesive 11 and conventional starch glue 8 in the direction of the center fold line 4, whereby the positive properties of both adhesives 8, 11 can advantageously be utilized plotted according to FIG. As an adhesive wet gumming 11 is proposed in the embodiment, but as alternatives are also the use sealant, in particular cold sealant, or a hot melt conceivable.

The production process for the production of the paper bag 10 according to the invention with the dust-tightly sealed fold lines 4, 4 "will be explained in the following: The adhesive in the form of wet gumming or the cold seal mass is applied cyclically to a paper roll or paper web 100 via a printing cylinder in a flexographic printing press. as shown in Figure 4. The adhesive 11 is applied in the region of the paper web 100, so that later in the subsequent process of bottom folding results in the adhesive pattern 11 shown in Figure 3.

The size and shape of the application surface and the application thickness of the activatable adhesive 11 or the cold seal mass can be made variable, for example, depending on the material used for the production of the paper bag 10 or the manufacturing process used or depending on the selected product for the produced Paper bag 10.

In the next step, the paper web 100 is folded in the so-called tube machine in the longitudinal direction overlapping and glued and so formed into a tube and then cut to a suitable length. The pre-printed with the adhesive 11 or cold seal tube sections are subsequently transported to the bottom layer of the manufacturing process. At the bottom layer, the sack bottoms 2 are folded, as shown in FIG. 3, and the known glue mixture 8 for bonding the cross bottom 2, as shown in FIG. 5, is applied to the side parts 5 and the corner stops 6. The glue 8 used is based on a starch-water mixture, wherein care must be taken during the application that it is recessed in the region of the side flap fold lines 4 and the edge regions of the side flaps 5 and corner folds 6. Also on the floor layer, a floor rinse is created along the side flap fold lines 4. The necessary to activate the adhesive 11 moistening is carried out by the applied starch-water mixture 8. This is achieved in that the adhesive 11 is activated by the capillary action of the paper. The water contained in the starch glue 8 spreads in the paper and diffuses to the adhesive sites 11, whereby these are dissolved and made adhesive in the manner of an envelope.

Optionally, the moistening of the adhesive 11 can be assisted by a suitable nozzle by means of water vapor.

The applied cross bottom 2 of the paper bag 10 according to the invention is now well sealed in the region of the side flap fold lines 4, the bottom middle channel 4 "and the edge regions 4 ', so that no more contents can escape, in particular in the area of the marked sack edges 20 of FIG significantly dustproof and thus prevents contamination of the bottling plant at the customer, as well as contamination of the filled bags 10 on the pallet.

The upper part 3 can be configured in analogy to the bottom 2.

Preferably, prior to collapsing the side parts 5, a so-called inner bar can additionally be applied, which closes the bottom part 2 of the paper bag 0 airtight. Such an inner bar consists for example of a plastic film which either completely covers the adhesive surfaces of the adhesive 11 or alternatively is only partially glued to certain surfaces of the adhesive 11. The bonding takes place in any case such that the opening of the bottom part 2 is completely airtight and dust-tight by means of the film is glued. The side parts 5 contribute to the dust-tight closure of the paper bag nothing, but the folding is only the optical design of the paper bag 10 for transport purposes. If an internal bolt is used, in principle, the rubber coating 11 could be dispensed with. When using an inner bar, it is possible in particular to proceed in such a way that a starch gluing frame is applied to the inner bar, which is then glued onto the opened bottom 2. Then the starch glue comes directly over the entire surface on the floor 2, so that no gumming is necessary. Another variant may be configured such that the rubber coating 11 for the Bodenverklebung is only partially covered by an inner bar. The uncovered part is then glued in the admission of the bottom 2.

Claims

claims 1. Paper bag for bulk materials such as cement, gypsum, granules, animal feed o. Ä., With a bottom and a bottom opposite the top, wherein the bottom and / or top are folded by adding the side panels to Seitenfalzlinien and glued, in particular in the form of a Cross or block floor, characterized  in that at least one adhesive or adhesive which can be activated after application is provided for bonding the side parts, which adhesive is applied continuously at least from one side-fold line to at least the opposite side-face line of the side parts. A paper bag according to claim 1, characterized in that the at least one applied adhesive or adhesive surface extends beyond at least one of the side fold lines, preferably right up to the edge of the end folds or beyond. 3. paper bag according to one of the preceding claims, characterized in that a plurality of strip-like and mutually parallel adhesive or adhesive surfaces are provided, wherein preferably at least two parallel strips are provided per Eckeinschlag. 4. Paper bag according to one of the preceding claims, characterized in that at least one non-continuous adhesive or adhesive surface or adhesive or adhesive strip is provided, fall whose / whose sub-sections at least on the Seitenfalzlinien and / or the middle fold line. 5. Paper bag according to one of the preceding claims, characterized in that the adhesive is a wet rubber which can be activated by liquid or steam, ideally water or water vapor, or the adhesive is a sealing compound, in particular a cold sealant. 6. Paper bag according to one of the preceding claims, characterized in that the folding of the bottom and / or upper part is additionally glued by means of a separately applied glue, in particular based on a starch-water mixture, wherein this glue dispenses the fold lines. 7. paper bag according to claim 6, characterized in that the glue and the adhesive or adhesive surfaces are applied alternately in the folding direction. 8. Paper bag according to one of the preceding claims, characterized in that at least one film is glued to the closure of the paper bag by means of the adhesive or adhesive and / or the glue with the side parts and / or end wefts. 9. paper bag according to claim 8, characterized in that the film covers the applied adhesive or adhesive surface completely or partially. A method for producing a paper bag with a folded bottom and / or top according to one of the preceding claims, characterized in that the activatable adhesive and / or adhesive is applied to a paper roll or paper web for producing the paper sacks and / or printed and then in Flooring the floor and / or the shell is folded. A method according to claim 10, characterized in that in the bottom layer a starch-water mixture is applied, so that an alternating adhesive / adhesive and strength range is formed, in particular alternately in the direction of the Seitenfalz- or center fold lines. Method according to one of claims 10 or 11, characterized in that activation of the pre-applied adhesive in the bottom layer by the addition of water and / or water vapor is activated, in particular by the application of the starch-water mixture. Method according to one of the preceding claims 10 to 12, characterized in that a film for air-tight bag closure by means of the applied adhesive and / or adhesive and / or the starch-water mixture is adhered to the folded still unfolded bottom and / or upper part , Method according to one of the preceding claims 10 to 13, characterized in that the adhesive and / or adhesive is applied via a printing cylinder clockwise on the paper web or roll of paper, in particular, the order is carried out in a flexographic printing machine. Method according to one of the preceding claims 13 to 14, characterized in that the adhered film completely or only partially covers the applied adhesive and / or adhesive surface.