DE102010014849A1 - Bag, preferably film packing bag, useful for receiving pourable packing products e.g. foods or detergents, comprises a bag body exhibiting flexible layer material and a reinforcement, and a foamed polymer material provided on reinforcement - Google Patents

Abstract

Bag, preferably film packing bag comprises: a bag body (1) exhibiting a flexible layer material and at least one reinforcement (7) to increase the mechanical stability; and a foamed polymer material (11), which is provided on the reinforcement. The two sections of the layer material are placed one above the other to form the reinforcement, and limiting connecting lines are connected to form a cavity along at least one of the reinforcements, where the cavity is filled with the foamed polymer material. An independent claim is also included for producing the bag, preferably film packing bag, comprising at least partially providing the flexible layer material with a foamable polymer material, placing the layer material sections of the layer material one above the other at least partially provided with the foamable polymer material during molding of the bag body, and connecting the connecting lines to form the cavity in such a manner that the foamable polymer material is found into the cavity, and subsequently filling the foamable polymer material into the cavity via foaming, and forming the reinforcement of the bag body.

Description

The invention relates to a bag, in particular a film packaging bag, having a bag body having a flexible layer material which has at least one reinforcement to increase the mechanical stability, wherein a foamed polymeric substance is present on the reinforcement. The invention also provides a method for producing a bag. The bag is intended in particular for receiving pourable packaged goods such as food, pet food, detergents, powdery or granular construction products or the like.

From the point of view of the use of resources, flexible layer materials, in particular films, are ideal packaging means, since these allow the best ratio of the amount of material used relative to the volume of the packaging body achieved. In addition to low material costs, the layer materials or prefabricated, unfilled packaging bags provided for forming bags can also be easily transported. The disadvantage is that conventional foil packaging bags have a comparatively low stability.

A film packaging bag with the features described above is known from US 2004/0005100 A1 known. The front wall and the rear wall of the bag body are each formed of a plurality of adhesive laminated film layers. Between two of the film layers, a foamed polymeric substance is arranged in strip-shaped regions which extend in the bag longitudinal and / or transverse direction. The front wall and the rear wall are connected at the edges by conventional longitudinal sealing seams. In the case of the known film packaging bag, there is the disadvantage that the production of the multilayer adhesive-laminated film, which has a frothable polymeric substance in the form of strips on the inside, is complicated.

A film packaging bag with the features described above and a method for its production are also from the EP 1 009 658 B1 known. To form a structurally stable article, which may be in the form of a film packaging bag, a flexible, windable on a coil film is provided. This film may have a sandwich structure with a first film layer, a second film layer and a foamable polymer substance arranged therebetween. After the formation of the container, energy is supplied to the film, so that the polymer substance is foamed over the entire surface.

Against this background, the invention has for its object to provide a bag, in particular film packaging bag, which has an increased strength and at the same time is easy to manufacture.

Starting from a bag with the features described above, the object is achieved in that two sections of the layer material to form the reinforcement superimposed and connected to form a cavity along at least one reinforcing connecting line, wherein the cavity filled with the foamed polymeric substance is. According to the present invention, the foamed polymeric substance is not integrated into the layer structure of the layer material forming the bag body. Rather, the foamed polymeric substance is at least partially disposed on the surface of the layer material, wherein the foamed cavity is formed by the fact that portions of the layer material are superimposed. In addition, the two sections are connected directly to one another at at least one connecting line, so that a clear limitation of the reinforcement takes place. This makes it possible to achieve a targeted, local stiffening by the inventive design gain. The cavity delimited by the at least one connecting line is inflated by the foamed polymer substance in a tubular or pillow-like manner. The foamed polymer substance itself has a comparatively soft consistency. However, the stiffening is achieved by the considerable volume and cross-sectional enlargement. The properties of the layer material itself usually remain unaffected. Embrittlement of the coating material or the risk of delamination of individual layers in the area of the foamed polymeric substance do not occur. In addition to a more structural stiffening of the bag body at the at least one reinforcement and a padding is achieved, which leads to a further increase in the load capacity for sudden impact of force. Preferably, a plurality of reinforcements are provided, which are designed as described above.

In particular, a reinforcement may be formed on the longitudinal sides of the bag in each case in that the layer material is folded over there, the cavity being formed between an outer edge of the side edge and a longitudinal sealing seam offset therefrom. In such a case, the bulge filled and bulged by the foamed polymeric substance is substantially tubular, with the reinforcement being confined to the interior of the bag body by the longitudinal sealing seam. Reinforcement in the area of the side edges is also particularly expedient, to give the bag, as it were, an outer supportive framework.

As a layer material usually a film is provided. In addition, however, in principle also tissue and nonwoven, each preferably made of plastic, can be used. In addition, laminates with at least one film layer and at least one textile layer, ie in particular woven or nonwoven, can also be used. The bag body may be formed from a single blank of the sheet material or from a plurality of separate sections.

The bag may be formed from a single blank of the sheet material by folding and heat sealing. Preferably, the bag is designed as a side-folding bag, the bag body has two front walls and at least on one longitudinal side a side fold. Usually gussets are arranged on both longitudinal sides between the front walls, which connect via the side edges of the front walls. Such a gusseted bag has approximately a cuboid shape, whereby the filling volume is maximized and space requirements are minimized. In a gusseted bag, the edges of the film either on a bag surface, i. H. a front wall or gusset, or merged at one of the side edges. In the context of the invention, it is advantageous if the edges of the layer material are brought together in the region of a bag surface, since then all side edges can be provided with a reinforcement according to the invention by folding over and producing a longitudinal sealing seam.

The bag, which is preferably provided on its longitudinal sides with at least one reinforcement, has a bottom portion and a head portion. The floor area may be formed, for example, as a floor stand. An opening of the bag is provided at the head portion, which may also have a reclosure, such as a zipper or slider closure. In order to be able to easily manufacture such a bag, it may be expedient if the at least one reinforcement extends only over a part of the respectively associated side edge, wherein the bottom area and / or the head area are not provided with a reinforcement.

In addition to substantially tubular reinforcements, which are formed by folding the film and creating a sealed seam, it is also possible to form reinforcements between two sealing seams, preferably two parallel sealing seams or even within a circumferential sealed seam. In two straight or in a curve parallel sealing seams a tubular or strand-like reinforcement is generated. A seal around the cavity results in a cushion-like shape of the reinforcement. By creating cavities between two sealing seams, reinforcements extending in the transverse direction, in particular in the bottom region and in the head region, can be produced, so that the entire bag can be provided with a net-like stiffening.

The selection of the layer material which is provided for the formation of the bag body, in the context of the invention is not further limited, since in contrast to the known from the prior art embodiments, no integration of the foamable polymer substance in the layer structure of this layer material is provided. Thus, in particular, a multilayer film may be provided in which the outer surface of the bag body is difficult or impossible to heat seal. In the formation of the bag body by folding and heat sealing, the outer appearance is not impaired in the production of the sealing seams. Such a multilayer film preferably comprises a sealable layer of polyolefin on the inner surface of the bag body. For example, laminated or coextruded films having an outer surface of polyethylene terephthalate (PET) and an inner surface of polyethylene (PE) are suitable. Without limitation, further film layers, for example for increasing the stability and / or the barrier effect, may be arranged between the inner layer and the outer layer.

In the case of a laminated film or another multilayer laminated layer material, it is also possible in particular to use a metallic layer or a metallized plastic layer, for example metallized polyethylene terephthalate. Also, composite materials having an outer layer of oriented polypropylene (O-PP) or layers of different polyethylene types can be used in the invention, wherein in the latter case, the polymer composition is suitably selected so that at a suitable sealing temperature, only the inner surface melts.

In addition to coextruded or multilayer laminated PE films but also heat-sealable monofilms, in particular PE monofilms can be used. Layer materials which are formed entirely from polyolefins are characterized by good recyclability.

While laminated film may have an inner print produced before lamination, coextruded films or monofilms are provided with a print on the outside, which can be covered with a protective paint to increase the abrasion resistance.

In one embodiment of the layer material as a film, this usually has a thickness between 60 and 300 .mu.m, wherein the layer thickness of the heat-sealable layer of polyolefin is typically between 50 and 150 microns. Depending on the material of the outer layer, this can be significantly thinner. The thickness of the film layer arranged on the outside of the bag body is typically between 10 and 100 μm, with materials such as PET or O-PP particularly preferably between 10 and 30 μm.

In order to form the reinforcements, as further explained below, a foamable polymer substance is first applied to the layer material before the bag body is formed. It may be provided either that the layer material outside the reinforcement or reinforcements is free from the foamed polymer substance and a foamed polymeric substance or that the layer material outside the reinforcement has a foamable polymer substance in the unfoamed state. In the latter case, during production, foaming takes place by supplying energy only at the cavities delimited by at least one connecting line, which are provided as reinforcements.

As polymer substance are all materials into consideration, which are expandable by a subsequent power supply. Depending on the type of foamable polymer substance, the energy input can be effected, for example, by temperature and / or by radiation, such as a microwave or laser. With an energy supply by radiation, the foamable polymer substance can also be added with absorbing additives. For example, microwave-active materials, in particular carbon black or carbon-based nanoparticles, can be added to the polymeric substance. These materials locally convert the radiation into heat, which is used for expansion. Also for laser radiation suitable materials can be added. The foaming reaction can be driven both physically, for example by the expansion of a gas or the evaporation of a liquid, or by a chemical reaction, for example the production of gas. The foamed polymeric substance may be formed, for example, on the basis of expandable polystyrene containing a blowing agent. Alternatively, expandable microspheres comprising a thermoplastic shell and a propellant are known as the material for the foamed polymeric substance. Such expandable particles can be incorporated in a polymer matrix, in particular an adhesive matrix.

The invention also provides a method for producing a bag, in particular a film packaging bag, which may be formed as described above, wherein a flexible layer material, in particular film, at least partially provided with a foamable polymer substance, wherein during the molding of a bag body from the at least Sections of the layer material with the foamable polymer substance layer are placed over one another and connected to form a cavity along at least one connecting line, that in the cavity foamable polymer substance is located, and wherein subsequently the cavity is filled by the foaming of the foamable polymer substance and a reinforcement of the bag body forms.

Within the scope of the process according to the invention, an adhesive with expandable particles distributed in it, in particular expandable polystyrene and / or expandable microspheres, can be applied as the foamable polymer substance.

According to a first variant of the process, this foamable polymer substance can be applied over the entire surface, with only local foaming occurring subsequently on the cavities formed. In such an embodiment of the method, the energy input must take place only in the region of the reinforcements to be formed. Furthermore, it must be ensured that, despite the full-surface coating with the adhesive, the stacked portions of the layer material are directly connected to each other, which can be achieved, for example, in a heat sealing by increased pressure, through which the adhesive applied over the entire surface is displaced at the sealing seam.

According to a second variant of the method, the foamable polymer substance is applied only to the locations of the layer material at which subsequently the at least one reinforcement is formed. The foamable polymer substance can be applied in a printing process, whereby a precise positioning must be carried out. It is also possible to apply the foamable polymer substance as a strand from an extruder or from a melt pump to the layer material. The operating parameters and the polymer substance are then selected so that initially no expansion takes place. If, as usual, the layer material is supplied as a material web, from which a plurality of bags are formed, a repeat must also be observed.

Finally, there is also the possibility of forming the foamable polymer substance, first of all, to apply an adhesive there to the layer material, where subsequently the Reinforcements should be formed. Subsequently, foamable particles are scattered or inflated onto the sheet material to adhere to the adhesive. The areas not provided with adhesive should remain free of foamable particles, for which purpose, for example, a blowing off of the layer material may be provided for the removal of loose, non-adhered particles.

The invention will be explained below with reference to a drawing showing only one embodiment. Show it:

1 the perspective of a foil pouch in a partially cutaway view;

2a and 2 B Detailed views of alternative embodiments of a reinforcement formed on one side edge;

3a a further education of in 1 illustrated foil packaging bag;

3b a section along the line AA the 3a ;

4 a foil packaging bag with additional reinforcement on a front wall.

1 showed a designed as a gusseted bag packaging bag, the bag body 1 with two front walls 2 as well as between the front walls 2 arranged and over side edges 3 to the front walls 2 subsequent gussets 4 from a single piece of one in the embodiment as a film 5 formed layer material is formed. The edges of the film 5 are on one of the front walls 2 merged and with a heat-sealable layer 6 the foil 5 forming the inner surface of the bag body 1 forms sealed together.

On all sides 3 are tubular inflated reinforcements 7 provided, extending over a part of the respectively associated side edges 3 extend and cause an increase in the mechanical stability of the gusseted bag.

A detail view of a reinforcement 7 is in 2a reproduced in a sectional view. At the side edges 3 is the multilayer film 5 folded on itself, taking in an offset to an outer edge 8th the side edge 3 a longitudinal sealing seam 9 runs, at which the superimposed sections of the film 5 on the heat-sealable layer 6 connected to each other. The longitudinal sealing seam 9 limits a cavity 10 containing a foamed polymeric substance 11 is filled. The cavity 10 is due to the polymer substance 11 inflated tubular, with the volume and cross-sectional enlargement a significant stabilization of the bag body 1 is reached. Because of the foamed consistency, the reinforcements 7 a certain elasticity and cushioning effect, whereby an additional protective effect against mechanical loads is achieved.

Of the 2a It can also be seen that the structure of the film 5 through the formation of reinforcement 7 is not changed. The foil 5 is usually multi-layered and has opposite the heat-sealable layer 6 a durable outer layer 12 on, which is expediently not or only with difficulty heat sealable. As outer layer 12 For example, PET or O-PP may be provided. The foil 5 can be both coextruded and multilayer laminated, with the heat-sealable layer between 6 and the outer layer 12 Further film layers, in particular functional layers can be arranged to increase the barrier effect and / or the stability.

According to the 2a will the film 5 so folded onto itself that the tubular, with the foamed polymeric substance 11 filled cavity 10 by only one longitudinal sealing seam 9 is limited. Alternatively, it is also possible to form the reinforcement between two spaced connecting lines or within a peripheral connecting line. 2 B shows an example of an embodiment in which a gain 7 between two mutually parallel longitudinal sealing seams 9 ' is formed. Such an embodiment may be provided, for example, if, in contrast to the embodiment according to the 1 the edges of the film 5 on one of the side edges 3 should be merged or if at the side edges 3 a trimming of the outer edge 8th' is provided.

3a shows a bag body 1 in which on all four side edges 3 reinforcements 7 are provided, extending over part of the length of the side edges 3 extend. In a lower area, a standing floor 13 and in an upper portion of the bag body 1 are the side edges 3 not with a reinforcement 7 Mistake. In the upper area of the bag body 1 the front walls are sealed together, where there is a Griffaustanzung 14 is introduced. Above the Griffaustanzung 14 is a non-sealed cavity 10 ' between the front walls 2 formed with the foamed polymer substance 11 is filled and accordingly a pillow-like reinforcement 7 ' forms ( 3b ). Through the cushion-like reinforcement 7 ' above the handle punching 14 the comfort of carrying the foil pouch on the handle punching can 14 be increased, wherein the uppermost portion of the bag body 1 better in the hands of a user and less strong cuts. In the embodiment of the 3a indicates the floor 13 at a transverse sealing seam another, transverse reinforcement 7 '' on.

In the production of the gusseted bag, the polymer substance in the initially foamed state can only partially there on the film 5 be applied where subsequently the reinforcements 7 . 7 ' . 7 '' should be formed. Alternatively, however, a full-surface application is possible, in which case only foaming by an energy supply to the reinforcements to be formed 7 . 7 ' . 7 '' he follows. In the case of a full-surface application, there is also the possibility of applying foil strips 15 on the foamable polymer coated heat-sealable layer 6 additional reinforcements 7 ''' to build. Such an embodiment is exemplary in the 4 shown. The foil strips 15 be at their edges, for example by heat sealing or gluing, with the inner surfaces of the front walls 2 connected, wherein then takes place between the connecting lines at the edges of a local energy supply and, accordingly, a foaming of the polymer substance present there.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2004/0005100 Al [0003]
• EP 1009658 B1 [0004]

Claims (16)

Bag, in particular foil packaging bag, having a bag body having a flexible layer material ( 1 ) which, to increase the mechanical stability, at least one reinforcement ( 7 . 7 ' . 7 '' ), wherein at the reinforcement ( 7 . 7 ' . 7 '' ) a foamed polymeric substance ( 11 ), characterized in that to form the reinforcement ( 7 . 7 ' . 7 '' ) two sections of the layer material superimposed and to form a cavity ( 10 ) along at least one of the reinforcement ( 7 . 7 ' . 7 '' ) connecting line are connected, wherein the cavity ( 10 ) with the foamed polymeric substance ( 11 ) is filled out. Bag according to claim 1, characterized in that the bag body ( 1 ) two front walls ( 2 ) and between the front walls ( 2 ) and over side edges ( 3 ) to the front walls ( 2 ) subsequent gussets ( 4 ) having. Bag according to claim 1 or 2, characterized in that the bag body ( 1 ) is formed from the layer material by folding and heat sealing. Bag according to one of claims 1 to 3, characterized in that on at least one side edge ( 3 ) the reinforcement ( 7 ) hose-shaped and to the interior of the bag body ( 1 ) by a longitudinal sealing seam ( 9 . 9 ' ) is limited. Bag according to claim 4, characterized in that on all side edges ( 3 ) a reinforcement ( 7 ) is provided. Bag according to claim 4 or 5, characterized in that the reinforcement ( 7 ) or reinforcements ( 7 ) only over a part of the respectively associated side edge ( 3 ) extends or extend. Bag according to one of claims 1 to 6, characterized by a reclosure. Bag according to one of claims 1 to 7, characterized in that the layer material is multi-layered and on a side which the inner surface of the bag body ( 1 ), a heat-sealable layer ( 6 ) having. Bag according to one of claims 1 to 8, characterized in that the layer material outside the reinforcement ( 7 . 7 ' . 7 '' ) or reinforcements ( 7 . 7 ' . 7 '' ) free of the foamed polymeric substance ( 11 ) as well as a foamable polymer substance. Bag according to one of claims 1 to 9, characterized in that the layer material outside the reinforcement ( 7 . 7 ' . 7 '' ) has a foamable polymer substance in the unfoamed state. Bag according to one of claims 1 to 10, characterized in that the foamed polymeric substance ( 11 ) is formed from expandable polystyrene. Bag according to one of claims 1 to 10, characterized in that the foamed polymeric substance ( 11 ) Microspheres comprising a thermoplastic shell and a propellant therein. Bag according to claim 11 or 12, characterized in that the polystyrene or the microspheres are incorporated in an adhesive matrix. A process for producing a bag, in particular a film packaging bag according to one of claims 1 to 13, wherein a flexible layer material is at least partially provided with a foamable polymer substance, wherein during the molding of a bag body ( 1 ) of the at least partially provided with the foamable polymer material layer material layers of the layer material superimposed on one another and to form a cavity ( 10 ) are connected along at least one connecting line that in the cavity ( 10 ) is foamable polymer substance and wherein subsequently the cavity ( 10 ) is filled up by the foaming of the foamable polymer substance and a reinforcement ( 7 . 7 ' . 7 '' ) of the bag body. The method of claim 14, wherein as the foamable polymer substance, an adhesive having dispersed therein particles of expandable polystyrene and / or expandable microspheres is applied. A method according to claim 14, wherein initially an adhesive is applied to the layer material in regions to form the foamable polymer substance and wherein subsequently foamable particles are applied to the layer material in order to adhere to the adhesive.

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