DE102011076538A1 - Method for producing a composite film for a tubular bag - Google Patents

Abstract

The invention relates to a method for producing a composite film (15c) for a tubular bag (1), wherein the composite film (15c) consists of a plurality of interconnected layers (16b, 24a, 25a, 29), wherein at least one of the layers (16b, 24a , 25a, 29) as a barrier layer (16b, 29) is formed, and wherein at least one further layer (29) is provided, which has a recess (30; 30a). According to the invention, it is provided that the composite film (15c) is produced by bonding a first layer structure (19) to a second layer structure (22), that the second layer structure (22) has the at least one further layer (29), and that the recess (30; 30a) is produced in the at least one further layer (29) prior to bonding to the second layer structure (22) in the second layer structure (22), and in that a mechanically strong layer (29) is produced for the second film layer structure (22) ), which is made by blowing.

Description

State of the art

The invention relates to a method for producing a composite film for a tubular bag according to the preamble of claim 1.

Such a method, in which a composite film is provided in the region of at least one layer with a recess, is made of US 2003/0128899 A1 known. In the known manufacturing process, the recesses are formed in a prefabricated, all layers comprising composite film subsequently, in particular by means of a laser, which are intended to facilitate the opening of the tubular bag by means of a straw. The disadvantage here is the relatively complicated control of the laser, since the recesses may be formed only in the designated layers of the composite film, and it must be avoided, for example, that barrier layers are damaged. This restricts the use of the described process as well as the useful materials for the composite film.

From the US 5,482,176 Furthermore, a packaging container is known, which consists of a multi-layered material comprising an inside and outside coated cardboard. The outer coating of the cardboard is recessed in the region of an opening device. Furthermore, the opening device is connected by means of an additional adhesive layer with the outer coating of the carton. By using the carton, the known composite film is not suitable for use in a soft bag package in the form of a tubular bag.

A composite film which is suitable for use with an opening device on a tubular bag is known from US Pat WO 2007/149231 A2 known. In the known composite film, a hole for the opening device is punched out, which is covered by the inside of the packaging container formed from the composite film with an additional, serving as a barrier layer material layer in the form of a packaging material strip. From the other side of the laminated film formed as a laminated film, the opening means is brought into coincidence with the punched hole and connected via an annular region with the packaging material strip. The opening device has a cutting device in the form of cutting teeth, which perforates or separates the additional material layer for opening the packaging container, in order to allow, for example, a pouring out of a liquid from the packaging container designed as a tubular bag.

Such packaging containers in the form of tubular bags are produced on so-called tubular bag machines. The holes for the opening devices are separated or punched out of the composite film stored as an endless packaging material web at a separate entry station. Subsequently, from the later inner side of the packaging container to the packaging material web, the material sections which form the later barrier layers are sealed.

The method using the last-mentioned composite film is relatively complicated due to the required punching of the packaging material web and subsequent sealing of the barrier layers, since an additional punching device and a sealing device are required. In particular, it can be problematic in this case that, in the case of a functional impairment at the punching device or at the sealing device, the entire production or filling process of the tubular bag machine has to be interrupted for a longer time. Moreover, it is to be regarded as disadvantageous that the original barrier layers were separated or destroyed by the punching of the hole and subsequent resealing of the hole through the material layer of the packaging material strip. This represents a potential weak point in that the production of the original barrier protection function requires a high-quality packaging material strip (in terms of material or thickness) and high process reliability.

Disclosure of the invention

Based on the illustrated prior art, the present invention seeks to provide a method for producing a composite film for a tubular bag according to the preamble of claim 1 such that this economical production of the composite film maximum flexibility with respect to the materials used for the composite film and a high-precision design of the recesses allows to ensure the highest possible barrier protection and process reliability in the production of the composite film. This object is achieved in a composite film having the features of claim 1. The invention is based on the idea to form the composite film by the use of two, interconnected layer structures, of which one layer structure contains the recesses for opening devices, wherein the layers of the composite film are formed as flexible layers.

Advantageous developments of the composite film according to the invention are specified in the subclaims. In the scope of the invention, all combinations of at least two of in the claims, the description and / or the figures disclosed features.

Manufacturing technology, the recesses can be produced with high precision and relatively low cost by a punching or laser process.

In particular, it is provided that the at least one further layer has at least one first carrier layer. In other words, this means that the recess is formed in the region of the first carrier layer. This is done because such, consisting of plastic backing layer usually with the usual opening means with plastic cutting teeth is not durchzutrennen, since the known carrier layers have a relatively high strength or toughness.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiment and from the drawings.

These show in:

1 a simplified side view of a filled with a filling tube bag with an opening device,

2 an opening device in a perspective view,

3 and 4 in each case sections through a composite foil with opening devices arranged on the composite foil,

5 a simplified representation for explaining the manufacturing process of a composite film for the production of tubular bags according to the 1 .

6 a packaging machine for the manufacture of filled with a filling tubular bags in a simplified representation,

7 to 11 a simplified representation for explaining the manufacturing method of a first alternative composite film and

12 to 14 a simplified representation for explaining the manufacturing process of a second alternative composite film.

In the 1 is as a tubular bag 1 trained packaging container simplified. The tubular bag 1 has an upper transverse seam 2 , a lower transverse seam 3 and at least one longitudinal seam 4 on. It can also be provided that in the bottom region or in the head region of the tubular bag 1 this is formed with a folded bottom or a folded head closure, for example, a stableness of the tubular bag 1 or to allow a particular visual appearance.

Preferably in the upper region of the tubular bag 1 but below the upper cross seam 2 , is on the outside wall 5 the tubular bag 1 an opening device 10 arranged. How best by the 2 can be seen, the opening means 10 , which preferably consists of plastic and is produced by injection molding, a base body 11 on top, with a removable lid closure 12 connected is. The screwable lid closure 12 acts with cutting teeth 13 together, with a rotation of the lid closure 12 in operative connection with the outer wall 5 the tubular bag 1 arrive to cut through this or form a passage and thus a removal of in the tubular bag 1 product 7 , eg a liquid product 7 milk, fruit juices or the like. Furthermore, the main body 11 a circumferential connection flange 14 on, for fixing the opening device 10 on the tubular bag 1 serves.

The material of the tubular bag 1 consists of a composite film consisting of flexible layers, in particular a laminate composite film 15 . 15a , and assigns according to the 3 and 4 by way of example and not limitation, to a construction which is on the inside of the tubular bag 1 first an LDPE sealing layer 16 (LDPE = low density polyethylene) has. To the LDPE sealant layer 16 closes an aluminum layer 17 at. On the aluminum layer 17 follows one in the extrusion process with the aluminum layer 17 connected MDPE layer 18 (MDPE = medium density polyethylene) ( 4 ). In the laminate composite film 15a according to the 3 is used instead of the MDPE layer 18 an adhesive layer 18a used.

The one from the LDPE sealant layer 16 , the aluminum layer 17 and the MDPE layer 18 or the adhesive layer 18a existing first layer structure 19 , which acts as a barrier layer or barrier layer composite is, by means of a in the 5 simplified manufacturing device shown 20 containing a co-extrusion device 21 comprising, with a second layer structure 22 connected. The second layer structure 22 includes a primer layer 23 , a print layer 24 and a carrier layer 25 , The second layer structure 22 comes with the first film layer construction 19 by means of in the 5 illustrated manufacturing facility 20 to the laminate composite film 15 respectively. 15a connected and to a packaging material roll 28 wound.

Essential to the invention is that the second layer structure 22 in the areas where in the manufacture of tubular bags 1 the opening devices 10 are arranged, one recess each 30 . 30a having. The recesses 30 . 30a in this case already in the manufacturing process of the second layer structure 22 by a corresponding production device, in particular by a (not shown) punching device or a laser beam cutting device in the second layer structure 22 generated or formed. In particular, it is essential that the recesses 30 at least in the area of the carrier layer 25 be formed, since the carrier layer 25 made of OPP (oriented polypropylene), PET or a mechanically similar loadable material or has such a strength / toughness that the cutting teeth 13 the opening device 10 these (usually) can not be severed.

Thus, the packaging material roll 28 with the rolled laminate composite foil 15 . 15a already the recesses 30 for the opening devices 10 on, wherein it is essential that the arrangement of the recesses 30 on the laminate composite foil 15 . 15a preferably at certain uniform intervals corresponding to the format of the laminate composite film 15 . 15a produced tubular bags 1 he follows. This is a waste-free processing of packaging roll 28 allows.

In the in the 3 illustrated embodiment of the invention has the recess 30 a size that is smaller than the size or the diameter of the connection flange 14 the opening device 10 , In this embodiment, the connection flange 14 with its underside with the backing layer 25 that the later outer wall 5 the tubular bag 1 trains, connected. The bonding is preferably carried out by means of an ultrasonic welding device or a heat-sealing device, not shown. This connects the connection flange 14 the opening device 10 with a particular radially circumferential connecting seam such that the connecting flange 14 with the carrier layer 25 is tightly connected. Furthermore, one recognizes on the basis of 3 in that the opening device 10 or the main body 11 or the cutting 13 not yet in operative connection with the first film layer structure 19 are. This is done only when opening the tubular bag 1 to remove the product 7 ,

In the in the 4 illustrated embodiment of the invention has the recess 30a a size or a diameter which is greater than the size of the connection flange 14 the opening device 10a , In this embodiment, the opening device 10a with its connection flange 14a on the MDPE layer 18 applied or connected thereto, preferably by an ultrasonic welding device, not shown.

In the 6 is a packaging plant 32 for producing tubular bags 1 from a packaging material roll 28 and filling the tubular bag 1 shown in simplified form. The packaging system 32 has transport rollers 33 . 34 on, by means of which the packaging material roll 28 is rolled off. There are also several, dancer rolls 36 having balancing devices 37 recognizable by means of which a balance between a cyclical advantage and a continuous preference of the material of the packaging material roll 28 in different areas of the packaging machine 32 is possible. The laminate composite film 15 comes after rolling in the area of a machine housing 38 the packaging machine 32 , being inside the machine housing 38 a sterile atmosphere or sterile conditions prevail. Inside the machine housing 38 is a sterilizer 39 arranged in which, for example, liquid hydrogen peroxide to sterilize the laminate composite film 15 located. Subsequently, the laminate composite film 15 by means of a drying device 40 dried and a vertical flow wrapper 42 fed.

The flow wrapper 42 has a form shoulder 43 and a forming and filling tube 44 on, with a storage, not shown, for the product to be filled 7 is coupled. The forming and filling tube 44 penetrates the machine housing 38 in the area of an outlet 45 , From the area of the outlet 45 prevail in the field of packaging machine 32 unsterile conditions. In the lower part of the forming and filling tube 44 one recognizes further a longitudinal seam sealing device 46 as well as two vacuum-assisted, intermittent pull-off belts 47 . 48 , Furthermore, one recognizes an application device 50 for attaching the opening means 10 to the outside wall 5 the tubular bag 1 , The application device not shown in detail 50 essentially comprises the already mentioned ultrasonic welding device and is preferably with a storage magazine for the opening means 10 coupled. It is essential here that the application device 50 still in the area of the forming and filling pipe 44 is arranged so that when attaching the opening means 10 on the outside wall 5 the later tubular bag 1 the forming and filling tube 44 a counterholder for the opening device 10 forms the required contact pressure of the connection flange 14 on the outside wall 5 to enable. Furthermore, it is essential that the application device 50 in the unsterile area. This will provide a direct access (in case of any) malfunction of the application device 50 allows, without the sterility of the upstream area of the packaging plant 32 to influence. It also eliminates the need for opening devices 10 to sterilize.

Below the forming and filling pipe 44 is a cross sealer 51 arranged, the two mutually movable transverse sealing jaws 52 and 53 , and (not shown) separating knife for separating a tubular bag 1 from the packaging material hose. Essential in the production process of the tubular bag 1 is that the application device 50 the opening devices 10 so with the recesses 30 . 30a align that in aligned registration with the recesses 30 . 30a reach.

In the 7 to 11 is the manufacturing process of a laminate composite film 15b shown in place of the laminate composite films 15 . 15a alternatively can also be used. Here, according to the 7 first the carrier layer consisting of PET or OPP 25a on its back with the printing layer having a printed image 24a printed. Subsequently, according to the 8th on the carrier layer 25a opposite side of the print layer 24a with a mechanically loadable layer 26 , for example, made of polyamide (PA) by an adhesive or extrusion lamination method. The carrier layer 25a , the printing layer 24a and the layer 26 thus form the second layer structure 22a out.

Subsequently, according to the 9 the recesses 30 . 30a in the second layer construction 22a educated. The second layer construction produced in this way 22a is then according to the 10 with a prefabricated intermediate layer 27 connected. This is done by extrusion lamination. The intermediate layer 27 includes, for example, polyester, polyamide, polypropylene with or without barrier coatings, mono- or multilayer films, which are produced by blow molding or casting or an aluminum foil with a thickness between 5 .mu.m and 15 .mu.m. In a final step according to the 11 In a further extrusion process, the intermediate layer 27 on the second layer construction 22a opposite side with the for forming the tubular bag 1 required sealant layer 16a , usually made of polyethylene, provided. In this case, by co-extrusion, the sealing layer 16a be coated with different polyethylene densities to control the adhesion and sealing properties.

In the in the 12 to 14 illustrated manufacturing process of the laminate composite film 15c is first in a first step according to the 12 on the carrier layer consisting of PET or OPP 25a on its back with the printing layer having a printed image 24a printed. Subsequently, according to the 13 the carrier layer 25a on the print layer 24a by an adhesive or extrusion lamination process with a prefabricated, blown, and therefore relatively high strength layer 29 , which is designed as a monolayer or multilayer, connected. The prefabrication also includes the formation of the recesses 30 . 30a , The layer 29 For example, by using suitable plastics such as EVOH or PVDC, it may have the required barrier function for product protection. In a third, in the 14 The illustrated step is the print layer 24a with the sealing layer 16b Mistake. This is preferably done by means of a cast-extrusion coating. In this case, slot dies for the production of the sealing layer 16b used. As a result, the polymer melt impinges shortly after the nozzle exit on cooling rollers and the carrier material (carrier layer 25a and print layer 24a ), which immediately freezes the molecular chain structure and keeps it short. This gives a very good cuttability, which is the opening of the tubular bag 1 through the opening device 10 . 10a facilitated. Instead of the described cast extrusion, it is also possible to use the carrier material (carrier layer 25a and print layer 24a ) by an adhesive lamination process with the layer 29 connect to.

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 2003/0128899 A1 [0002]
• US 5482176 [0003]
• WO 2007/149231 A2 [0004]

Claims (10)

Method for producing a composite film ( 15c ) for a tubular bag ( 1 ), wherein the composite foil ( 15c ) of several interconnected layers ( 16b . 24a . 25a . 29 ), wherein at least one of the layers ( 16b . 24a . 25a . 29 ) as a barrier layer ( 16b . 29 ), and wherein at least one further layer ( 29 ) is provided, which has a recess ( 30 ; 30a ), characterized in that the composite foil ( 15c ) by joining a first layer structure ( 19 ) with a second layer structure ( 22 ), that the second layer structure ( 22 ) the at least one further layer ( 29 ), and that the recess ( 30 ; 30a ) in the at least one further layer ( 29 ) before joining to the second layer structure ( 22 ) in the second layer structure ( 22 ) and that for the second film layer structure ( 22 ) a mechanically strong layer ( 29 ), which is made by blow molding. A method according to claim 1, characterized in that the mechanically strong loadable layer ( 29 ) is formed as a monolayer or multilayer, and that the layer ( 29 ) by means of an adhesive or an extrusion process with a printing layer ( 24a ), which in turn is connected to a carrier layer ( 25a ) connected is. Method according to claim 1 or 2, characterized in that the layer ( 29 ) to form a barrier function EVOH (ethylene vinyl alcohol) or PVDC (polyvinylidene chloride). Method according to claim 2 or 3, characterized in that on the printing layer ( 24a ) a sealing layer ( 16b ) is applied. A method according to claim 4, characterized in that the application of the sealing layer ( 16b ) is carried out by a cast-extrusion coating. Method according to one of claims 1 to 5, characterized in that in the composite film ( 15c ) a plurality of equally spaced recesses ( 30 ; 30a ) be generated. Method according to one of claims 1 to 6, characterized in that the formation of the recess ( 30 ; 30a ) takes place by a punching or laser process. Method according to one of claims 1 to 7, characterized in that the at least one further layer at least a first carrier layer ( 25a ), preferably consisting of oriented polypropylene (OPP), polyethylene terephthalate (PET). Method according to one of claims 1 to 8, characterized in that the production of the composite film ( 15c ) includes an extrusion process. Method according to one of claims 5 to 9, characterized in that the application of the sealing layer ( 16b ) takes place through slot dies.

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