DE102009020710A1 - Packaging film useful for food packaging or pharmacy product packaging, comprises a carrier layer, a plastic substrate staggered with pigments, a silicon oxide- or aluminum oxide- or metallized barrier layer, and an intermediate layer - Google Patents

Abstract

The packaging film comprises a carrier layer (2), a plastic substrate (3) staggered with pigments (4), a silicon oxide- or aluminum oxide- or metallized barrier layer (6), and intermediate layers (5) arranged between the carrier layer and the barrier layer and adjacent on the barrier layer. The intermediate layer is free from pigments identical with the pigments provided in the carrier layer. The intermediate layer is formed from the same plastic substrate like the carrier layer, where titanium dioxide is provided in the carrier layer as pigment. The packaging film comprises a carrier layer (2), a plastic substrate (3) staggered with pigments (4), a silicon oxide- or aluminum oxide- or metallized barrier layer (6), and intermediate layers (5) arranged between the carrier layer and the barrier layer and adjacent on the barrier layer. The intermediate layer is free from pigments identical with the pigments provided in the carrier layer. The intermediate layer is formed from the same plastic substrate like the carrier layer, where titanium dioxide is provided in the carrier layer as pigment. Polyethylene terephthalate, oriented polypropylene, oriented polyamide and/or oriented polylactide is provided as plastic substrate in the carrier layer. The barrier layer is applied by sputtering or chemical vapor deposition and is printable external layer. A layer equipped with pigments is provided on the side of the carrier layer turned away the barrier layer. The barrier layer has a thickness of 35-60 nm and the intermediate layer has a thickness of 1.0 mu m. The carrier layer has a thickness of 10 mu m. The filling grade of the pigment in the carrier layer is 25% related to the carrier layer substrate weight. The film is sterilizable. An independent claim is included for a method for the production of a packaging film.

Description

The invention relates to a film, in particular a packaging film, comprising a carrier layer comprising a plastic substrate mixed with pigments, having at least one SiO _x or Al _y O _z barrier layer and at least one intermediate layer arranged between the carrier layer and the barrier layer and adjacent to the barrier layer , Furthermore, the invention relates to a packaging, a packaged product and a method for producing a film.

Multilayer packaging films are known, comprising a PET carrier layer which is mixed with TiO ₂ pigments for purposes of opacification. Directly on this PET carrier layer is usually another thin, also with TiO ₂ pigments offset layer. In order to achieve good barrier properties in terms of minimal moisture and gas permeability in the known packaging film, it is endeavored to provide the known packaging film with an SiO ₂ barrier layer, which is arranged directly on the adjacent to the PET carrier layer, with TiO ₂ -. Pigments offset layer is applied. However, no satisfactory barrier properties could be achieved.

Of the Invention is therefore the object of a packaging film with a pigmented carrier layer by applying a Barrier layer to achieve good barrier properties. It also exists the object is a package comprising such a packaging film as well a product packed with such packaging. About that In addition, the object is to provide a method for producing a like previously described optimized film.

This object is achieved in a generic film in that the adjacent to the barrier layer intermediate layer is free of identical with the pigments provided in the carrier layer pigments. With regard to packaging, the object is achieved by at least partial formation of the packaging from a film designed according to the concept of the invention. With regard to the packaged product, the object is achieved by the use of a packaging provided with a film provided according to the concept of the invention. With regard to the method, the object is achieved by first providing a carrier layer comprising a pigmented plastic substrate, to which at least one intermediate layer is applied which is free of pigments identical with the pigments provided in the carrier layer and / or free of pigment wherein an SiO _x , Al _y O _z barrier layer or metallized layer, for example an aluminum layer or an aluminum alloy layer, is applied directly to this intermediate layer.

advantageous Further developments of the invention are specified in the subclaims. In the context of the invention, all combinations of at least two features disclosed in the specification, claims and / or figures. To avoid repetition should be disclosed according to the device Features disclosed as procedurally apply and be claimable. Likewise, procedurally disclosed features disclosed as a device apply and be claimable.

The invention is based on the finding that the poor barrier property of the film, in particular a packaging film, obtained in experiments, could be due to the presence of pigments in the intermediate layer immediately adjacent to the barrier layer after application of the barrier layer. Obviously, the particle size of the pigments is so large that the comparatively thin barrier layer is penetrated by the pigments present in the intermediate layer, which in turn results from the fact that the barrier layer is applied directly to an intermediate layer in which pigments are present. the pigments provided with the pigments in the carrier layer (preferably a bulk layer) are identical. To circumvent the problem, the invention proposes at least not to provide in the intermediate layer immediately adjacent to the barrier layer the type of pigments which are also provided in the carrier layer. Most preferably, the intermediate layer is completely free of pigments. Also, the intermediate layer is preferably transparent. In a film formed according to the concept of the invention, therefore, the SiO _x or Al _y O _z barrier layer or a metallized layer, for example an aluminum layer or an aluminum alloy layer, is present as a barrier layer on an intermediate layer having a comparatively smooth surface, from which either or even no, but at least not protrude pigments that are identical to the pigments, in particular TiO ₂ , the support layer. The intermediate layer therefore preferably has a planarizing, ie abenbenende function. In this way, on the one hand, the adhesion of the barrier layer is improved and, on the other hand, puncturing of the preferably comparatively thin barrier layer with the aforementioned pigments is reliably avoided, as a result of which optimal barrier layers can also be achieved in the case of an opaque film. With regard to the formation of the barrier layer, there are different possibilities. It is particularly preferred if the barrier layer is SiO _x -containing, such as SiO ₂ -containing, and / or of SiO _x , such as of SiO ₂ be stands. In addition or as an alternative, the barrier layer may contain, for example, Al _x O _y , such as Al ₂ O ₃ , or may be formed from Al _x O _y , such as Al ₂ O ₃ . Alternatively or alternatively, the barrier layer may be, for example, a metallized layer of one or more metals of the series aluminum, iron, chromium, nickel, gold, silver or copper. With the help of such barrier layers, a good gas tightness, in particular with respect to oxygen, can be achieved. In addition, moisture penetration is avoided, but at least greatly minimized.

Also in view of the number of layers of the film to be realized There are many different possibilities. in principle it is preferred to add between the barrier layer and the pigmented layer backing provide only a single intermediate layer, which then inevitably free with the in the carrier layer provided pigments identical pigments, most preferably even pigment-free, is. For In the case of providing several intermediate layers, at least the free immediately adjacent to the barrier layer intermediate layer from those provided in the carrier layer Pigments are identical pigments or preferably free of pigment. It should be avoided that pigments layer directly into the barrier extend. It is also possible on the side facing away from the barrier layer side of the carrier layer to provide one or more layers, including one embodiment is feasible, in which the carrier layer an outer layer forms the film. The at least one intermediate layer and / or the at least one on the side facing away from the barrier layer side the carrier layer provided layer can / can for example by lamination, painting or curtain coating be applied.

Also with regard to the concrete training of the barrier layer adjacent intermediate layer, there are different possibilities. Preferably, the intermediate layer consists of a plastic substrate, most preferably from the same plastic substrate, in particular PET, like the carrier layer.

Likewise, there are different possibilities with regard to the formation of the pigments in the carrier layer. Thus, it is conceivable, for example, the carrier layer, in particular with the aim of opacification with organic pigments, such as organic color pigments and / or with inorganic pigments, such as sulfates and carbonates of Ba, Ca and Mg, also zinc white (ZnO) and ZnO (zinc oxide ), ZnS (zinc sulfide) or BaSO4 (barium sulfide), very particularly preferably TiO ₂ or mixtures of said pigments.

When Plastic substrate for forming the carrier layer, for example PET (polyethylene terephthalate) are provided. Also is the use of OPP (oriented polypropylene) conceivable, where the polypropylene may alternatively be monoaxially or biaxially oriented. Also is it is conceivably used as a plastic substrate oPA (oriented polyamide) be, wherein the polyamide be monoaxially or biaxially oriented can. Similarly, PLA (polylactic acid) can be used as a plastic substrate become. Preferably, the plastic substrate is um an oriented film (foil), whereby also unoriented plastic substrates, For example, be used on PP (polypropylene) basis.

It is particularly expedient to apply the SiO _x or Al _y O _z barrier layer to the intermediate layer by PVD coating (physical vapor deposition). Alternatively, the use of a CVD method (chemical vapor deposition) is conceivable, wherein the barrier layer is particularly preferably applied by sputtering (cathode sputtering). In layers of SiO _x , x may represent a number from 1 to 2, preferably from 1.8 to 2.0. In barrier layers of Al _x O _y , x: y may represent a number of 0.5 to 0.66, with a number of 0.6 to 0.66 being preferred. The thickness of the barrier layers containing or consisting of SiO _x or Al _x O _y , resp. consisting or containing SiO ₂ or Al ₂ O ₃ , may be at least 5 nm (nanometers).

All Particularly preferred is an embodiment of the film in which the barrier layer is an outermost layer forms. Preferably, the barrier layer is printable, or optionally printed with paint and / or varnish.

As already hinted, it is conceivable on the of the barrier layer opposite side of the carrier layer at least one, preferably only one, an outer layer to provide the film-forming layer. Very particularly preferred this layer provided with pigments, preferably with pigments, which are identical to the pigments of the carrier layer.

In a development of the invention, it is advantageously provided that the barrier layer has a basis weight of between about 50 and about 200 mg / m ² . Or the barrier layers of SiO _x or Al _x O _y or containing SiO _x or Al _x O _y , for example, in a thickness of 1 to 1000 nm, preferably from 10 to 80 nm and in particular from 35 to 60 nm before. Metallized layers may have a thickness of, for example, 1 to 100 nm, preferably from 3 to 80, and preferably from 10 to 50 nm.

In a further development of the invention is advantageously provided that the intermediate layer has a thickness from a range between about 0.5 and 25 .mu.m, preferably between 0.8 and 2.3 .mu.m, particularly preferably about 1 .mu.m.

Especially preferred is an embodiment at the carrier layer a thickness of between about 4 and 200 microns, preferably between 6.4 and 18.4 μm, more preferably about 10 μm, having.

Especially it is preferred if the degree of filling the pigments in the carrier layer between about 2% by weight and about 25% by weight, based on the carrier layer polymer, chosen is.

The Invention leads also on a packaging, in particular a food packaging or a pharmaceutical product packaging, in particular for a medicament packaging, comprising a packaging film formed according to the concept of the invention. The packaging film is characterized by good barrier properties in terms of oxygen and moisture.

Further leads the Invention to a trained with one as described above Packaging packaged product, especially a food product or a pharmaceutical product, especially a drug.

In addition, the invention leads to a method for producing a film as described above, in particular a packaging film. In this case, initially an already coated or uncoated carrier layer is provided, which is formed from a pigmented plastic substrate. An intermediate layer which is free of pigments identical to pigments provided in the carrier layer and / or which is free of pigment is applied to this carrier layer either directly or on at least one layer provided on the carrier layer. An SiO _x or Al _y O _z barrier layer, preferably in a PVD or CVD method, is then applied directly to this intermediate layer.

All more preferably, the film is sterilizable, especially at Temperatures up to 135 ° C for one hour, at least at about 121 ° C for half Hour. The sterilization is very particularly preferred under saturated Steam atmosphere, in particular by sprinkling with hot water. Preferred are / is the substrate and / or the intermediate layer formed of PET.

Further Advantages, features and details of the invention will become apparent the following description of preferred embodiments and by reference the drawings.

These show in:

1 A first embodiment of a trained as a three-layer film packaging film,

2 an alternative embodiment of a packaging film, consisting of a total of five layers, and

3 an alternative embodiment of a packaging film comprising four layers.

In The figures are the same elements and elements with the same Function marked with the same reference numerals.

In 1 is a film designed as a packaging film 1 partially shown in cross section. Evident is a comparatively thick carrier layer 2 (Bulk layer). The carrier layer 2 has a thickness of about 10 microns in the embodiment shown. The carrier layer 2 is formed by a plastic substrate 3 , here PET, which contains pigments 4 , here inorganic TiO ₂ pigments, is added. This gives the carrier layer 2 a white color.

In the drawing plane above borders on the carrier layer 2 a single intermediate layer 5 which is completely pigment-free. Basically, it would also be enough if the interlayer 5 is not provided with pigments which are identical to the pigments 4 from the carrier layer 2 ; that means in the concrete embodiment that the intermediate layer 5 at least free of TiO ₂ pigments. The intermediate layer 5 consists in the embodiment shown from the same plastic substrate 3 like the carrier layer 2 , so here from PET.

The intermediate layer 5 is a so-called skin layer with a (substantially) smaller thickness extension than the carrier layer 2 - In the illustrated embodiment, the intermediate layer 5 a thickness of only 2 microns.

Immediately on the intermediate layer 5 on the support layer 2 opposite side is a barrier layer 6 with a thickness of 40 nm. At the barrier layer 6 In the exemplary embodiment shown, this is an SiO _x layer, such as an SiO ₂ layer, which has been applied by a PVD method. Alternatively, it may also be an Al ₂ O ₃ layer, or another, generic Al _y O _z layer. By doing that, the interlayer 5 in the embodiment shown is completely free of pigment, no pigments protrude from the intermediate layer 5 into the very thin barrier layer 6 in, whereby it provides optimal barrier properties.

2 shows an alternative embodiment with a carrier layer 2 consisting of a plastic substrate 3 , here PET, alternatively oPP, oPA or PLA, where the plastic substrate 3 with pigments 4 , here TiO ₂ , is offset. Immediately to the carrier layer 2 borders a layer 7 in which it is an intermediate layer. The layer 7 is with pigments 4 , here with TiO ₂ pigments added. The layer 7 is made of the same plastic substrate 3 designed as the carrier layer 2 , Immediately to the shift 7 borders on that of the carrier layer 2 opposite side a pigment-free intermediate layer 5 on, in turn, directly on the SiO ₂ barrier layer 6 (alternatively Al ₂ O ₃ layer) is located. The barrier layer 6 forms as in the embodiment according to 1 an outermost layer. At the shift 7 as well as the intermediate layer 5 are thin skin layers with a thickness of about 2 microns, whereas the barrier layer 6 is substantially thinner and has a thickness extension in the illustrated embodiment of 35 nm.

In contrast to the embodiment according to 1 is located on the of the barrier layer 6 opposite side of the carrier layer 2 another layer 8th which forms an outermost layer. The layer 8th is also with pigments 4 offset and made of the same plastic substrate 3 designed as the carrier layer 2 ,

3 shows a further alternative embodiment of a film formed as a packaging film 1 , This comprises a comparatively thick carrier layer 2 from a plastic substrate 3 , which with pigments 4 is offset. To this carrier layer 2 directly adjoins an intermediate layer in the drawing plane above 5 that's free of the pigments 4 is. In the embodiment shown, the intermediate layer 5 completely pigment-free, with the intermediate layer 5 is substantially thinner than the carrier layer formed as a bulk layer 2 , To the intermediate layer 5 borders on that of the carrier layer 2 opposite side a barrier layer 6 with a substantially smaller thickness extension, wherein the barrier layer is alternatively an SiO _x or an Al _y O _z layer. The barrier layer 6 forms an outermost layer of the film formed as a packaging film 1 , as well as a layer 8th on the from the barrier layer 6 opposite side of the carrier layer 2 ,

Also, an alternative embodiment can be realized, the in 3 having shown layer structure and in which of the intermediate layer 5 remote layer 8th pigments 4 , in particular the same pigments, here TiO ₂ , as in the carrier layer 2 are provided.

Very particular preference is given to the production of a film comprising a barrier layer 6 , First provided a three-layer film, which is a comparatively thick, central carrier layer 2 that has with pigments 4 is offset. Preferably, this carrier layer carries 2 on both sides in each case one, in particular single, layer, the layer facing the later barrier layer then the pigment-free intermediate layer 5 forms or at least an intermediate layer 5 that is free of those in the backing layer 2 provided pigments 4 , Most preferably, the three-layer film is produced by coextrusion. In this case, two alternative three-layer films can be realized, namely a first alternative, in which both, on opposite sides of the carrier layer 2 provided, layers free of the pigments 4 the carrier layer 2 are. Most preferably, the two layers are identical. In an alternative, second embodiment, the two layers are formed differently, for example, those on the of the barrier layer 6 opposite side of the carrier layer 2 arranged layer contains pigments, very particularly preferred, the same pigments, which are also in the carrier layer 2 are provided.

In order to ensure optimum sterilizability of the film obtained, it is particularly preferred if the three-layer film is completely made of PET, ie all three layers comprise as the base substrate PET, wherein the carrier layer 2 and possibly the barrier layer 6 opposite layer of pigments 4 , in particular TiO ₂ , comprises.

I. Example of a possible film according to the invention:

Construction:

• • carrier layer of PET with TiO ₂ pigments; Thickness of the carrier layer 10 μm
• • Intermediate layer of PET without TiO ₂ pigments arranged on the carrier layer; Thickness of the intermediate layer 1 μm
• • Interlayer barrier layer of SiO _x
• PET layer on the side of the carrier layer without TiO ₂ pigments which is remote from the intermediate layer; Thickness of the PET layer 1 μm
• - Oxygen transmission rate: 1.0 cc m² .day.bar
• - Water vapor transmission rate: 0.5 G m² · day

II. Comparative Examples

• 1. Structure as inventive film according to Example I, but with provided in the intermediate layer and the PET layer TiO ₂ pigments
• - Oxygen transmission rate: 17 cc m² .day.bar
• - Water vapor transmission rate: 18 G m² · day
• 2. Construction as film according to the invention according to Example I, but in both the intermediate layer and PET layer and in the support layer no TiO ₂ pigments
• - Oxygen transmission rate: 1.4 cc m² .day.bar
• - Hydrogen transmission rate: 1.2 G m² · day

1

foil

2

backing

3

Plastic substrate

4

pigments

5

interlayer

6

barrier layer

7

layer

8th

layer

Claims (17)

Film, in particular packaging film, with a carrier layer ( 2 ) comprising one with pigments ( 4 ) offset plastic substrate ( 3 ), with at least one SiO _x , Al _y O _z or metallized barrier layer ( 6 ) and at least one between the carrier layer ( 2 ) and the barrier layer ( 6 ), to the barrier layer ( 6 ) adjacent intermediate layer ( 5 ), characterized in that the intermediate layer ( 5 ) is free of those in the carrier layer ( 2 ) provided pigments ( 4 ) identical pigments ( 4 ). Film according to claim 1, characterized in that the intermediate layer ( 5 ) is pigment-free. Film according to one of claims 1 or 2, characterized in that a single intermediate layer ( 5 ) between the carrier layer ( 2 ) and the barrier layer ( 6 ), or that several intermediate layers ( 5 ) are provided and at least the immediately adjacent to the barrier layer ( 6 ) arranged intermediate layer ( 5 ), preferably exclusively this intermediate layer ( 5 ), is free of those in the carrier layer ( 2 ) provided pigments ( 4 ) identical pigments ( 4 ) or preferably is pigment-free. Foil according to one of the preceding claims, characterized in that the intermediate layer ( 5 ) of a plastic substrate ( 3 ), preferably from the same plastic substrate ( 3 ) like the carrier layer ( 2 ), is trained. Foil according to one of the preceding claims, characterized in that in the carrier layer ( 2 ) as pigments ( 4 ) organic pigments and / or inorganic pigments, in particular TiO _{2 are} provided. Foil according to one of the preceding claims, characterized in that as plastic substrate ( 3 ) in the carrier layer ( 2 ) PET and / or oPP and / or oPA and / or PLA is provided. Film according to one of the preceding claims, characterized in that the barrier layer ( 6 ) by PVD, in particular sputtering, or CVD or is applied. Film according to one of the preceding claims, characterized in that the barrier layer ( 6 ) is a, in particular printable, outer layer. Film according to one of the preceding claims, characterized in that on the of the barrier layer ( 6 ) facing away from the carrier layer ( 2 ) at least one, preferably an outer layer of the film ( 1 ), preferably with pigments ( 4 ) provided, layer is provided. Film according to one of the preceding claims, characterized in that the barrier layer ( 6 ) has a thickness of between about 1 and 100, preferably between about 3 and 8 nm, in particular between about 35 and 60 nm. Foil according to one of the preceding claims, characterized in that the intermediate layer ( 5 ) has a thickness of between about 0.5 μm and about 25.0 μm, in particular between 0.8 and 2.3 μm, preferably about 1.0 μm. Foil according to one of the preceding claims, characterized in that the carrier layer ( 2 ) has a thickness of between about 5 μm and 200 μm, in particular 6.4 to 18.4 μm, preferably about 10 μm. Film according to one of the preceding claims, characterized in that the degree of filling of the pigments ( 4 ) in the carrier layer ( 2 ) is selected from a range between about 2% and about 25%, based on the support layer substrate weight. Film according to one of the preceding claims, characterized in that the film ( 1 ) is sterilizable. Packaging, in particular food packaging or pharmaceutical product packaging, comprising a film ( 1 ) according to any one of the preceding claims. Packed with a package according to claim 15 Product, in particular food product or pharmaceutical Product, preferably drug. Method for producing a film ( 1 ), in particular packaging film, according to one of claims 1 to 15, with the steps: • providing a coated or uncoated carrier layer ( 2 ) comprising one with pigments ( 4 ) offset plastic substrate ( 3 ), • application of at least one intermediate layer ( 5 ) which is free of those in the carrier layer ( 2 ) provided pigments ( 4 ) identical pigments and / or pigment-free on the carrier layer ( 2 ), and • applying a SiO _x or Al _y O _z barrier layer ( 6 ) on the intermediate layer ( 5 ).