EP2790918A1

EP2790918A1 - Film product for packaging products in sealed film packages

Info

Publication number: EP2790918A1
Application number: EP12700644.3A
Authority: EP
Inventors: Ingo Putsch; Gerhard SCHOONE
Original assignee: Windmoeller and Hoelscher KG
Current assignee: Windmoeller and Hoelscher KG
Priority date: 2011-12-15
Filing date: 2012-01-11
Publication date: 2014-10-22
Also published as: US20140363544A1; WO2013087226A1; CN104169083A; CA2859257A1; US10046896B2

Abstract

The invention relates to a film product (10) for packaging products, particularly liquids (200), pasty and/or pourable materials, in sealed film packages (100), said film product having at least two film layers (20a, 20b). The film layer (20a) directed outwards is thermally stable and the film layer (20b) directed inwards is sealable, and both film layers (20a, 20b) are produced by a water-cooled blow coextrusion process.

Description

Foil product for packaging products in sealed

Plastic packaging

Description

The present invention relates to a film product for the packaging of products in sealed film packaging, a process for the production of a film product and a film package with a packaging space, which is at least partially filled with a product.

In principle, it is known that film products are used to store and transport products, in particular liquids, in sealed film packaging. Frequently FFS machines (Form, Fill, Seal) are used. In this case, endless hoses or film webs are mostly used, which can be filled in a common filling and sealing process with cargo or liquids. Such film packages are often consumer packaging, so that, for example, detergent or the like in such a film packaging can be packed. For the production of such film packages in FFS machines, sealing jaws are necessary which seal the film product, in particular individual film layers, with one another to produce a sealed seam The sealing jaws are heated to a sealing temperature in order to melt or melt part of the film product, which requires a certain amount of contact between the sealing jaws and the film product in order to transfer sufficient amounts of heat.

In known devices, it must be noted that the sealing process does not cause contamination of the sealing jaws. For this purpose, either work is done with relatively low sealing temperatures or the sealing jaws are temporarily coated with a Teflon tape. As a result, either the Teflon tapes need to be replaced at certain intervals and, on the other hand, the low sealing temperatures lead to relatively long cycle times when producing the sealed seam. In both cases, the productivity of such machines decreases.

It is already known that so-called asymmetric film products are used to provide a sealable film layer and a thermally stable film layer together in the form of a film product. In the known film products, these two layers are produced together by a laminating process. This has the disadvantage that both film layers must be produced separately and then a lamination process must be performed. This significantly increases the cost of such asymmetric films, so they are rarely used for the production of film products for FFS machines. It is also known that blow coextrusion machines are used for the production of tubular bags which produce different film layers in the coextrusion process. From DE 10 2009 046 539 A1 a possibility of a blow-extrusion process is basically known. Similarly, a blow-coextrusion process can also be performed. There, a so-called dry co-extrusion process step is shown, wherein from the outside and from the inside an air cooling is provided for the extruded film tube. However, in these blow coextrusion processes disadvantageous that in asymmetric film layer assemblies with different melting points, a curl or a so-called Curle effect occurs. By cooling after leaving the nozzle thermally induced stresses in the material of the film product, which produce a curl of the film product. Such produced film composites of different film layers are only partially operational, since they have disadvantages in terms of transparency and surface finish. The curling effect or the tendency to curl also means that use in FFS machines is possible only to a limited extent or only at low cycle times.

It is an object of the present invention to at least partially overcome the disadvantages described above. In particular, it is an object of the present invention to provide a film product, a film package as well as a method by means of which fast cycle times of high quality for a film product when used in an FFS machine can be made available.

The above object is achieved by a film product with the features of claim 1, by a method having the features of claim 10 and by a film package having the features of claim 15. Further features and details of the invention will become apparent from the dependent claims, the description and the drawings. In this case, features and details that are described in connection with the film product according to the invention, of course, also in connection with the inventive method and the film package according to the invention and in each case vice versa, so that with respect to the disclosure of the individual aspects of the invention always reciprocal reference is or may be ,

An inventive film product for the packaging of products, in particular liquids, pasty and / or free-flowing materials, in sealed film packages has at least two film layers. It is characterized in that the outwardly directed film layer is thermally stable and the inwardly directed film layer is sealable. Furthermore, the two film layers or all film layers of such a film product are produced by a water-cooled blow coextrusion process. With a film product according to the invention, the advantages of an asymmetric arrangement of the film layers are combined with the cost-effective production methods of a blow coextrusion process. This is possible according to the invention in that the blow coextrusion process is a water-cooled blow coextrusion process. As a result, with high cooling rates, in particular substantially shock-like, the film product can be cooled after it has left the extrusion die. This cooling with strong cooling rates means that only to a limited extent or no thermally induced stresses in the composite material of the film layers are produced. By reducing these residual stresses, the curl or curl effect is reduced to a minimum. In this way, the desired film composite of an asymmetrical arrangement of the film layers can be produced in this way in a cost-effective blow coextrusion process in a single step, without the disadvantages of such a blow coextrusion process occurring in an asymmetric film composite variant. This combination can save costs in production, since only a single manufacturing step for the film product is necessary. At the same time, the film product is produced with the desired high quality and, in particular in contrast to expensive lamination processes, can be produced in a single process step by blow coextrusion.

Surprisingly, it has been found that at least the outwardly directed, thermally stable film layer also has great advantages in terms of its transparency or gloss due to a film product according to the invention. However, this applies in particular to all film layers of a film product according to the invention.

An inventive film product can be used in particular in so-called FFS machines. By providing a thermally stable layer on the outside and a sealable film layer on the inside, it is possible to work with relatively high sealing temperatures, since the thermally stable layer prevents or reduces adhesion of the material to the sealing jaws of the FFS machine. Such high sealing temperatures can speed up the cycle times of the FFS machine. In addition, preferably can be dispensed with a coating of the sealing jaws, in particular by a Teflon tape. This increases not only the cycle time but also the continuous one Operating time of the sealing jaws. Of course, a plurality of film layers can be used, wherein at least the outer and the inner film layer are formed in accordance with the invention.

In the case of a film product according to the invention, "thermally stable" means that no or only a very slight melting of this material takes place in the region of the sealing temperatures This can be provided, for example, by polyamide or polyamide variants understand that this can be deformed at the desired sealing temperatures and in particular melts. This means that between a sealable film layer and a thermally stable film layer is in particular a significant difference between the respective melting temperature. For example, melting temperatures of between about 130 ° C and about 220 ° C are provided for the thermally stable film layer, in particular polyamide. The sealable film layer is in particular polyethylene or similar materials, wherein a melting temperature is provided, for example, between about 90 ° C and about 120 ° C.

A water-cooled blow coextrusion process is a process which can also be referred to as an upside-down wet process. In this case, an extrusion bubble is formed running from top to bottom, which is in particular water cooled from the outside and / or from the inside. The water preferably comes into direct cooling contact with the material of the respective film layer. The molten material of the film layers preferably leaves the nozzle of such a blow coextruder at a temperature in the range between about 180 ° C and about 260 ° C. Subsequently, water is used for cooling, which preferably has a temperature range between about 5 ° C and about 45 ° C has.

With a film product according to the invention, an improved runnability in FFS machines can also be provided by the reduced curling effect or the reduced tendency to curl. The individual film layers preferably add up to a total thickness of the film product in the range between about 20 μηι and about 1,000 μηι, in particular in the range of about 100 μηι. The film product can have a wide variety of designs and is in particular a transparent film product. Of course, but the individual film layers bring a variety of different properties with it, the whole as a film product z. As with regard to color or barrier properties bring a corresponding training with it. The film product according to the invention can be further processed into "pouches", for example in FFS machines. Even more complex film packaging, such. As stand-up pouches, can be achieved in the context of the present invention by means of a film product according to the invention. Such a film product can be upgraded even further during the filling or even earlier by a printing process. In particular, by an inventive film product and the correspondingly low tendency to curl or the low Curleffekt such printing can take place at higher web speeds or with higher process reliability. This is also advantageous since only a slight to no delay of the printed image on the film product is to be expected.

It may be advantageous if, in the case of a film product according to the invention, an adhesion promoter layer is arranged between the thermally stable film layer and the sealable film layer. An adhesion promoter as an adhesion promoter layer is to be understood as meaning a material which creates a bond between otherwise difficultly bondable layer materials of the individual film layers. In particular, in the provision of significantly more than two film layers, it may be advantageous if in each case an adhesive layer is disposed between the respective adjacent film layers. For example, such an adhesion promoter layer can have two different sides, so that a polar bond can be formed on one side and a non-polar bond on the other side. The bonding agent layer is preferably also introduced by means of the blow coextrusion process as the third layer of material between the two outer film layers.

Furthermore, it is advantageous if, in the case of a film product according to the invention, the thermally stable film layer has at least one of the following materials:

- polyamide (PA)

Polyester or polyethylene terephthalate (PET)

Polybutylene terephthalate (PBT) Polypropylene (PP)

Polyethylene with higher density (PE)

The preceding, non-exhaustive list describes possible materials only by way of examples. Preferably, a variant is used in which at least partially polyamide is provided as material for the thermally stable film layer.

Furthermore, it may be advantageous if, in the case of a film product according to the invention, the sealable film layer has at least one of the following materials:

Ethylene vinyl acetate (EVA)

Surlyn (ionomer)

Ethylene acrylic acetate (EAA)

Ethylene methyl acrylate (EMA)

ml_L (metallocene linear low density PE)

LL (linear low density PE)

- Bynell

Also, the foregoing enumeration of materials describes only a non-exhaustive selection of possible materials for the sealable film layer. Preferably, polyethylene or a material of polymer components with ethylene will find use here.

A further advantage can be achieved in that, in the case of a film product according to the invention, at least one film layer has increased barrier properties, in particular measured in permeability per area and time, with respect to at least one of the following substances:

- oxygen (0 ₂ )

- Air

- carbon dioxide (C0 ₂ )

- Flavorings

- perfumes

Steam Components of the product

Again, this is a non-exhaustive list of possible barrier properties. In this case, the corresponding film layer can be both the thermally stable and the sealable film layer, as well as an additional film layer. If a multiplicity of different barrier properties is desired, a multiplicity of film layers can accordingly also be arranged between the innermost and outermost film layers. In this case, individual film layers can also have more than one barrier property. Preferably, however, a flexible combination of the individual properties takes place through a combination of the corresponding film layers set by material selection.

It may also be advantageous if, in the case of a film product according to the invention, at least one film layer has one of the following properties:

- color property,

- Antiblock property,

Sliding property,

- antioxidant property,

- UV protection,

- puncture resistance,

- rigidity,

- Toughness.

Also in this list is not a non-exhaustive list. As a color property z. B. to understand the coloring of one of the film layers. These properties can also be produced with the existing outermost film layers, ie the thermally stable film layer and the sealable film layer, or by separate additional film layers. In this case, the respective properties can relate both to the visual or haptic perceptions of the film product, as well as its handling properties in the further processing process, in particular in an FFS machine. It may also be advantageous if, in the case of a film product according to the invention, at least one additional film layer having an additional property is arranged between the two outermost film layers, in particular between a bonding agent layer and the inwardly directed film layer. An additional film layer may, for. B. be provided with a property as shown in the two preceding paragraphs. The provision of an additional film layer has the advantage that the desired properties of sealability or thermal stability for the two outermost film layers are not impaired by this additional property. Thus, a particularly high flexibility of use of a film product according to the invention is possible, since by any Intermediate additional film layers flexibly adapted to the particular application film products can be achieved. In addition, the cost intensity for such a film product is reduced, since in all cases, ie for a substantially arbitrarily large number of additional film layers, the same process, namely a blow coextrusion process can be used. In particular, while a plurality of film layers is superposed, such. B. ten or more film layers.

In addition, it may be advantageous if, in the case of a film product according to the invention, the film layers together have a thickness of between about 20 μm and about 1,000 μm, in particular between about 50 μm and about 200 μm. Preferably, thicknesses of about 100 μηι are provided. Thus, in principle, a geometrical framework is specified in which film products according to the invention can lie. In this context, a blow coextrusion is particularly simple and inexpensive to carry out.

A further advantage can be achieved in that the film product according to the invention is designed as a continuous bag bag or as a film web. The film web is preferably an endless tube bag which has been cut along its longitudinal extent.

Another object of the present invention is a process for the production of a film product having at least two film layers, wherein a film layer is thermally stable and a film layer is formed sealable. Such a process is characterized in that the film product is produced by means of water-cooled blowing Coextrusion is produced. A method according to the invention results in particular in a film product according to the present invention, so that the same advantages can be achieved by such a method as have been explained in detail with reference to a film product according to the invention.

A method according to the invention can be developed in such a way that it is cooled with water in a temperature range of about 5 ° C. and about 45 ° C. Thus, after leaving the die, the material can be cooled to a range below about 100 ° C at about 180 ° C to 260 ° C. Preferably, temperatures of less than about 80 ° C or in particular between about 40 ° C and about 70 ° C are provided as the target cooling temperature. It should be noted that within the material, a temperature profile between the core of the material and the surface of the material is generated by the cooling. The above residual temperatures are in particular the maximum temperature in each case in the material. The water for cooling may be modified water, e.g. B. by means of additives which reduce the surface tension with respect to the wettability of the film product. In particular, surfactants such as rinsing agents can be used as a modification for the cooling water. Decalcified and / or demineralised water (distilled water) may also be used in the present invention.

A further advantage can be achieved by carrying out an air exchange in the interior of the coextrusion bubble in a method according to the invention. This improves the heat dissipation, so that the cooling performance is further improved without additional cooling from the outside. It is also possible that is cooled in a process according to the invention in the interior of a coextrusion bubble with air or water. The additional cooling, in particular air cooling, serves to further improve the cooling, so that a reduced final temperature after cooling can be achieved at the same extrusion speed.

It is also possible that in a method according to the invention a film product according to the present invention is produced. This leads to the same advantages, as already explained in detail above. Another object of the present invention is a film package with a packaging space, which is sealed liquid-tight with at least one sealed seam and at least partially filled with a product, in particular with a liquid. A film packaging according to the invention is characterized in that at least two film layers surround the packaging space, which are produced by a water-cooled blow coextrusion process, wherein the outwardly directed film layer is thermally stable and the film layer directed into the packaging space can be sealed. A packaging space can also be understood to mean a cavity inside this film packaging. The film layers together preferably form a film composite, which together forms the film product and completely encloses the packaging space. The sealing seam may run along a straight line or along a curve or a curvature.

It is possible that in a film packaging according to the invention the packaging space is filled with a food, in particular with an oil-containing liquid, and / or with a combustible liquid. Also, various liquids, in particular a multi-phase filling, is conceivable within the scope of the present invention. An oil-containing liquid is to be understood in particular as cooking oil, for example olive oil. A food is in particular a suitable material for consumption.

In a film package according to the invention, this film layer may at least partially comprise a film product according to the invention. Furthermore, it is possible that, in the case of a film packaging according to the invention, the film product has been produced in accordance with a method according to the invention. Thus, a film packaging according to the invention brings the same advantages as have been explained in detail with respect to a film product according to the invention and with reference to a method according to the invention.

The present invention will be explained in more detail with reference to the accompanying drawing figures. The terms "left", "right", "top" and "bottom" used herein refer to an alignment of the drawing figures with normally readable reference numerals. They show schematically: FIG. 1 shows a schematic side view of an upside-down wet process of a method according to the invention,

Figure 2 shows an embodiment when sealing a novel

Film product,

FIG. 3 a shows a partial representation of a film product according to the invention,

FIG. 3b shows the partial view according to FIG. 3a in a different temperature situation,

FIG. 4 a shows a partial representation of a film product according to the invention,

FIG. 4b shows a detailed representation of FIG. 4a at a different temperature situation,

FIG. 5a shows an embodiment of a film product according to the invention,

FIG. 5b shows a further embodiment of a film product according to the invention,

Figure 5c shows another embodiment of a film product according to the invention and

FIG. 6 shows a further embodiment of a film product according to the invention and a film package.

1 shows schematically a possibility for the production of a film product 10 according to the invention with a method according to the invention. For this purpose, an extrusion blowing device 300 is provided, which has a nozzle 320. From this nozzle 320, various film layers are extruded in coextrusion over each other in coextrusion. The resulting film tube or the resulting extrusion blister is directly the film product 10 and runs from top to bottom as a transport direction.

From the outside, a water cooling 310 is arranged in an annular manner around the film product 10. It includes the coextrusion bubble 90, so to speak. This water cooling 310 has cooling water 312, which can come into direct contact with the extrusion bladder 90 via a cooling gap 314. Thus, directly after the nozzle 320, the freshly prepared film product 10 of the extrusion bladder 90 can be cooled directly and in particular in a shock-like manner. The cooling is carried out with preferably about 5 ° C to 45 ° C cold water, so that a final final temperature of less than about 100 ° C of the coextrusion blister 90 is achieved.

The result of such shock-like cooling in asymmetric films is z. B. shown in Figures 3a to 4b. In Figure 3b is shown how z. B. directly after leaving the nozzle, the two film layers 20 a and 20 b behave to each other. If cooling is slow, the cooling behavior of the two film layers 20a and 20b differs from one another, so that a corresponding dimensional change of the two film layers 20a and 20b results, as shown in FIG. 3b. Due to the fact that the two film layers 20a and 20b are coextruded with each other, however, they are in a connection to each other, so that, as shown in Figure 4a, this dimensional change leads to a curvature of the film product 10 in different ways. This is the so-called curl or the Curleffekt.

Wrd now, according to the present invention, for. B. according to Figure 1, a water cooling used in particular for shock-like cooling, so this change is omitted. Rather, so to speak, the film product 10 is frozen in the manner shown in Figure 3a. Accordingly, such as. B. Figure 4b shows, without this dimensional change and a thermally induced stress omitted, so that the Curleffekt or curl is reduced or omitted.

Due to the fact that the film product 10 can be produced much smoother, in particular with a better flatness, it also has better running properties in a so-called FFS machine (form, fill and seal machine). The crucial process is in such a machine, the sealing process, as z. B. Figure 2 is apparent. There, a sealing device 400 with two sealing jaws 410 is shown. By way of illustration, a film product 10 is shown schematically, which already forms a film package 100 in a bag-like manner. The storage space 120 may be filled with a product, e.g. B. be filled with liquid 200. The outer film layer 20a is thermally stable and the inner Film layer 20b sealable. If the sealing operation is carried out with the sealing jaws 410, these two sealing jaws 410 are fed to one another. They are heated to a sealing temperature and transfer this temperature to the material of the film product 10. This temperature is preferably below the melting temperature of the thermally stable film layer 20a and sufficient to melt or fusing the sealable film layer 20b. As a result of the melting or melting, the two inner film layers 20b are fused together, so that a material-locking connection with a sealed seam is formed. At the same time, the thermally stable outer film layer 20a protects the sealing jaw 410 against contamination by molten material. Accordingly, the sealing jaws 410 can be used directly and need not be protected, e.g. B. by means of a Teflon tape.

FIGS. 5a to 5c show various embodiments of a film product 10 according to the invention. In the simplest case, the film product 10 is provided with only two film layers 20a and 20b, which have been produced together in a coextruded manner. This can be seen in Figure 5a wherein the film layer 20a is outwardly directed and thermally stable while the inner film layer 20b is sealably formed.

FIG. 5b shows a variant in which an adhesion promoter layer 20c is additionally provided between the two outer film layers 20a and 20b. This bonding agent layer 20c serves, in particular, to enable the two other film layers 20a and 20b to be firmly and securely joined together in the desired manner, even if the combination of materials is unfavorable.

In Figure 5c an embodiment is shown by way of example, in which an additional film layer 20d, z. B. with an additional property is provided. This additional film layer 20d is preferably located between an adhesion-promoting layer 20c and the sealable film layer 20b. Of course, a plurality of additional film layers 20d may be used, each having one or more additional properties, for. B. in terms of barrier properties or further processing properties have. FIG. 6 shows an embodiment of a film package 100 according to the invention. This has film products 10 which together surround a packaging space 120 in a pouch-like manner. This packaging space 120 is at least partially filled with liquid 200 and closed at the top and bottom, each with a sealed seam 1 10. The generation of these sealing seams is z. B. by a method according to Figure 2 has been performed.

The above explanation of the embodiments describes the present invention only in the context of examples. Of course, individual features of the embodiments, if technically feasible, can be combined freely with one another, without departing from the scope of the present invention.

B ez u se c h e l iest

film product

a thermostable film layer sealable film layer adhesion promoter layer further film layer

Koextrussionsblase

film packaging

seal

packing room

liquid

extrusion blow

water cooling

cooling water

cooling gap

jet

sealer

sealing jaw

Claims

Patent claims

1. film product (10) for the packaging of products, in particular liquids (200), pasty and / or free-flowing materials, in sealed film packages (100), comprising at least two film layers (20a, 20b),

characterized,

in that the outwardly directed film layer (20a) is thermally stable and the inwardly directed film layer (20b) is sealable, and in that the two film layers (20a, 20b) are produced by a water-cooled blow coextrusion process.

2. film product (10) according to claim 1,

characterized,

an adhesion promoter layer (20c) is arranged between the thermally stable film layer (20a) and the sealable film layer (20b).

3. film product (10) according to any one of the preceding claims,

characterized,

in that the thermally stable film layer (20a) comprises at least one of the following materials:

- polyamide (PA)

Polyester or polyethylene terephthalate (PET)

Polybutylene terephthalate (PBT)

Polypropylene (PP)

Polyethylene with higher density (PE)

4. film product (10) according to one of the preceding claims,

characterized,

the sealable film layer (20b) comprises at least one of the following materials:

Ethylene vinyl acetate (EVA)

Surlyn (ionomer)

Ethylene acrylic acetate (EAA)

Ethylene methacrylate (EMA) ml_L (metallocene linear low density PE)

LL (linear low density PE)

- Bynell

5. film product (10) according to any one of the preceding claims,

characterized,

in that at least one film layer (20a, 20b, 20c, 20d) has increased barrier properties with regard to at least one of the following substances:

- oxygen (0 ₂ )

- Air

- carbon dioxide (C0 ₂ )

- Flavorings

- perfumes

- Steam

6. film product (10) according to any one of the preceding claims,

characterized,

in that at least one film layer (20a, 20b, 20c, 20d) has one of the following properties:

- Color property

- Antiblock feature

- Sliding property

- Antioxidant property

- UV protection

- puncture resistance

- stiffness

- Toughness

7. film product (10) according to any one of claims 5 or 6,

characterized,

in that at least one additional film layer (20d) with an additional property between the two outermost film layers (20a, 20b), in particular between an adhesive layer (20c) and the inwardly directed film layer (20b).

8. film product (10) according to any one of the preceding claims,

characterized,

that the film layers (20a, 20b) together have a thickness of between about 20 μηι and about 1000 μηι, in particular between about 50 μηι and about 200 μηι.

9. film product (10) according to any one of the preceding claims,

characterized,

in that the film product (10) is an endless tubular bag or a film web.

10. A method for producing a film product having at least two film layers, wherein a film layer is thermally stable and a film layer is sealable.

characterized,

in that the film product (10) is produced by means of a water-cooled blow coextrusion process.

1 1. A method according to claim 10,

characterized,

that is cooled with water in a temperature range between about 10 ° C and about 45 ° C.

12. The method according to any one of claims 10 or 1 1,

characterized,

in that an air exchange is carried out inside a coextrusion bubble (90).

13. The method according to claim 12,

characterized,

that air is cooled inside a coextrusion bubble (90).

14. The method according to any one of claims 10 to 13,

characterized,

a film product (10) having the features of one of claims 1 to 9 is thus produced therewith.

15. film packaging (100) having a packaging space (120) which is closed in a liquid-tight manner with at least one sealed seam (110) and at least partially filled with a product, in particular with a liquid (200),

characterized,

in that at least two film layers (20a, 20b) surround the packaging space (120) produced by a water-cooled blow coextrusion process, wherein the outwardly directed film layer (20a) is thermally stable and the film layer (20b) directed into the packaging space (120) is sealable.

16. film packaging (100) according to claim 15,

characterized,

the packaging space (120) is filled with a food, in particular an oil-containing liquid, and / or with a combustible liquid.

17. film packaging (100) according to any one of claims 15 or 16,

characterized,

the film layers (20a, 20b) are produced at least partially from a film product according to one of claims 1 to 9.

18. film packaging (100) according to any one of claims 15 to 17,

characterized,

in that the film product (10) is produced by a method having the features of one of claims 10 to 14.