LAMINATED PACKAGING MATERIAL COMPRISING A BARRIER FILM AND PACKAGING CONTAINERS MANUFACTURED THEREFROM

Abstract

A packaging laminate that includes a barrier film having a PECVD barrier coating of diamond-like carbon is disclosed, along with a method of manufacturing such films, and laminated packaging materials comprising such films, in particular intended for liquid food packaging are disclosed. Packaging containers that include the laminated packaging material or being made from the laminated packaging material, in particular to a packaging container intended for liquid food packaging are also disclosed.

Claims

1. A laminated packaging material for packaging of liquid food products, the laminated packaging material comprising: a barrier film, wherein the barrier film comprises a substrate layer in the form of a web or sheet, a first coating of an amorphous diamond-like carbon (DLC) in contact with the substrate layer, a first outermost liquid tight, heat sealable polymer layer on a first side of the barrier film, wherein the first outermost polymer layer is providing the outermost surface of a packaging container made from the laminate packaging material, and a second, innermost liquid tight, heat sealable polymer layer on the opposite, inner and second side of the barrier film, wherein the second, innermost polymer layer is providing the innermost surface of a packaging container made from the packaging material to be in contact with the packed product.

2. The laminated packaging material of claim 1, wherein the substrate layer is a polymer film substrate.

3. The laminated packaging material of claim 1, further comprising a bulk layer of paper or paperboard or other cellulose-based material.

4. The laminated packaging material of claim 1, further comprising a bulk layer of paper or paperboard or other cellulose-based material, and the barrier film, wherein the barrier film is bonded to a first side of the bulk layer by a bonding layer, such as a thermoplastic polymer bonding layer, said first outermost liquid tight, heat sealable polymer layer applied onto the opposite, second and outer, side of the bulk layer, while said second innermost liquid tight, heat sealable polymer layer is applied on the inner side of the barrier film, which is opposite to the side that is bonded to the bulk layer.

5. The laminated packaging material of claim 4, wherein the bonding layer binds together the surface of the first DLC coating of the barrier film and the surface of said first side of the bulk layer.

6. The laminated packaging material of claim 1, wherein the bonding layer is in direct contact with the first surface of the barrier film, i.e. the surface of the first DLC coating.

7. The laminated packaging material of claim 1, wherein the first DLC coating is a barrier coating.

8. The laminated packaging material of claim 1, wherein the substrate layer of the barrier film has an adhesion-promoting primer coating on its other side, opposite the side coated with the barrier coating, and wherein the barrier film is bonded to the second innermost liquid tight, heat sealable polyolefin layer by the adhesion-promoting primer coating.

9. The laminated packaging material of claim 8, wherein the adhesion-promoting primer coating is formed by a composition of one or more compounds selected from the group consisting of aminosilanes and polyethyleneimines.

10. The laminated packaging material of claim 8, wherein the adhesion-promoting primer coating is a second coating of an amorphous diamond-like carbon (DLC).

11. The laminated packaging material of claim 1, wherein the barrier film of the laminated packaging material is a double barrier film, which comprises a first barrier film being laminated and bonded to a further identical or similar second barrier film by an interjacent thermoplastic bonding layer.

12. The laminated packaging material of claim 1, wherein a first barrier film is laminated and bonded to a further identical or similar second barrier film by an interjacent thermoplastic bonding layer, and wherein the laminated packaging material further comprises a first outermost liquid tight, heat sealable polymer layer on the opposite, not laminated side of the barrier film and a second innermost liquid tight, heat sealable polymer layer on the opposite, not laminated side of the barrier film.

13. The laminated packaging material of claim 1, wherein the substrate layer comprises a polymer film comprising a polymer selected from the group consisting of a polyester, a polyamide, an ethylene vinyl alcohol copolymer (EVOH), a polyolefin, and a blend of any of said polymers.

14. The laminated packaging material of claim 13, wherein the substrate layer comprises a multilayer film having a surface layer comprising at least one of said polymers.

15. The laminated packaging material of claim 1, wherein the first amorphous diamond-like coating (11b; 25; 35a) is 2 to 50 nm thick.

16. The laminated packaging material of claim 1, wherein the second amorphous diamond-like carbon coating, acting as an adhesion-promoting primer coating, is 2 to 50 nm thick.

17. The laminated packaging material of claim 1, wherein the substrate layer is an oriented PET film.

18. The laminated packaging material of claim 1, wherein the substrate layer is 8 to 12 m thick.

19. The packaging container comprising the laminated packaging material as defined in claim 1.

20. The laminated packaging material of claim 1, wherein the second amorphous diamond-like carbon coating, acting as an adhesion-promoting primer coating, is 2 to 10 nm thick.

Description

EXAMPLES AND DESCRIPTION OF PREFERRED EMBODIMENTS

[0071] In the following, preferred embodiments of the invention will be described with reference to the drawings, of which:

[0072] FIG. 1a is showing a schematic, cross-sectional view of a laminated packaging material of a multilayer film type, according to an embodiment of the invention,

[0073] FIG. 1b shows a schematic, cross-sectional view of a further embodiment of a laminated packaging material of the multilayer film type,

[0074] FIG. 2 is showing a schematic, cross-sectional view of a laminated packaging material comprising a bulk layer, according to another embodiment of the invention,

[0075] FIG. 3 is showing a schematic, cross-sectional view of a further laminated packaging material comprising a bulk layer, according to a further embodiment of the invention,

[0076] FIG. 4 shows schematically a method, for laminating the barrier film of the invention into a laminated packaging material of the type of FIGS. 2 and 3, for liquid food packaging, having a core or bulk layer of paperboard or carton,

[0077] FIGS. 5a, 5b, 5c and 5d are showing typical examples of packaging containers produced from the laminated packaging material according to the invention, and

[0078] FIG. 6 is showing the principle of how such packaging containers are manufactured from the packaging laminate in a continuous, roll-fed, form, fill and seal process.

EXAMPLES

Example 1

[0079] Films from 12 m thick biaxially oriented polyethyleneterephthalate (BOPET Hostaphan RNK12 and RNK12-2DEF by Mitsubishi) were deposition coated with various coatings by plasma enhanced chemical vapour deposition (PECVD) under vacuum conditions, in a roll-to-roll plasma reactor. A diamond-like amorphous hydrogenated carbon coating, DLC, was coated on some film samples, in line with the invention, while other PECVD barrier coatings were coated on other samples. The other PECVD barrier coatings, subject of comparative examples, were SiOx, wherein x varied between 1.5 and 2.2, SiOxCy coatings and SiOxCyNz coatings, respectively, wherein (y+z)/x is from 1 to 1.5. These other silicon-containing barrier coatings were formed from organosilane pre-cursor gas compounds. The film samples according to the invention, were coated by depositing an amorphous, hydrogenated diamond-like coating DLC from a plasma formed from pure acetylene gas.

[0080] The plasma employed was capacitively coupled to the power delivered at 40 kHz frequency, and magnetically confined by unbalanced magnetron electrodes placed at a distance from the circumferential surface of a rotating drum, which functioned as a combined film-web transporting means and electrode. The polymer film substrate was cooled by cooling means within the drum web-transporting means.

[0081] The DLC coating was in a first example applied to a thickness of about 15-30 nm, and in a second example to a thickness of only about 2-4 nm.

[0082] The SiOx coatings were coated to a thickness of about 10 nm.

[0083] The thus barrier-coated substrate film samples, were subsequently extrusion coated with a 15 g/m2 thick layer of low density polyethylene (LDPE), of a type corresponding to LDPE materials of the laminate bonding layer that is conventionally used in order to extrusion laminate paperboard to aluminium foil in liquid carton packaging laminates.

[0084] The adhesion between the thus extrusion coated LDPE layer and the barrier-coated substrate PET film, was measured by a 180 peel test method under dry and wet conditions (by putting distilled water at the peeling interface) as described above. An adhesion of more than 200 N/m ensures that the layers do not delaminate under normal manufacturing conditions, e.g. when bending and fold-forming the laminated material. A wet adhesion of this same level ensures that the layers of the packaging laminate do not delaminate after filling and package formation, during transport, distribution and storage.

TABLE-US-00001 TABLE 1 PE- PE- laminate laminate Water Peel force Peel force Oxygen Vapour (N/m) (N/m) wet Coating type Barrier Barrier Dry adhesion adhesion SiOx (x = 1.5-2.2) <3 cc at 3 N/A 40-50 0 Mean 1.5 cc SiOxCy (y/x = 1-1.5) <3 cc at 3 1 40-50 40-50 Mean 1.5 cc SiOxCyNz <3 cc at 3 1 200-300 100 (y + z/x = 1-1.5) Mean 1.5 cc DLC ~25 nm <3 cc at 3 0.8 350-400 350-400 Mean 1.5 cc DLC ~25 nm on 0.5 0.05 0.5 350-400 350-400 both sides of film DLC 2-4 nm 60-80 5-6 350-400 350-400 DLC 2-4 nm on 60-80 5-6 350-400 350-400 both sides of film

[0085] OTR was measured with Oxtran 2-60 (Mocon Inc.) equipment based on coulometric sensors, with a standard deviation of the results being 0.5 cm.sup.3/m.sup.2/day.

[0086] The method for determining OTR identifies the amount of oxygen per surface and time unit at passing through a material at a defined temperature, given atmospheric pressure, and chosen driving force.

[0087] Water vapour transmission rate (WVTR) measurements were carried out by a Lyssy instrument (norm: ASTM F1249-01 using a modulated Infrared sensor for relative humidity detection and WVTR measurement) at 38 C. and 90% driving force. This test method is dedicated to measure Water Vapor Transmission Rate (WVTR) properties of films. The procedure is done according to ASTM F1249-01 using a modulated Infrared sensor for relative humidity detection and WVTR measurement.

[0088] As can be seen from the results summarised in Table 1, there is some insufficient dry adhesion between pure SiOx barrier coatings and thereonto extrusion coated LDPE, while the adhesion deteriorates completely under wet/humid conditions.

[0089] When experimenting with more advanced SiOx formulas, containing also carbon and nitrogen atoms, some improvement is seen in the dry and/or wet adhesion properties, as compared to the pure SiOx coating, but the wet adhesion properties remain insufficient, i.e. below 200 N/m.

[0090] The dry adhesion of a DLC coating to extrusion coated LDPE is slightly better than for the best of the tested SiOxCyNz coatings. The more important and unforeseeable difference, compared to the SiOxCyNz coatings is that the adhesion remains constant under wet or humid conditions, such as are the conditions for laminated beverage carton packaging.

[0091] Furthermore, and rather surprisingly, the excellent adhesion of DLC coatings at values above 200 N/m, remain unaffected also when the DLC coating is made thinner, and as thin as 2 nm, i.e. where there is actually no notable barrier properties obtained any longer. This is the case both regarding dry and wet conditions for the sample films.

[0092] Of course, when such films are laminated into packaging laminates of paperboard and thermoplastic polymer materials, it is advantageous to coat such a DLC coating on both sides of the film, in order to provide excellent adhesion on both sides of the film. Alternatively, the adhesion to adjacent layers on the opposite side of the substrate film, may be secured by a separately applied chemical primer composition, such as the 2 DEF primer from Mitsubishi. A DLC adhesion-promoting layer is preferable from both environmental and cost perspective, since it only involves carbon atoms in the adhesion layer, and since it may be made very thin in order to just provide adhesion, or thicker in order to provide also barrier properties. At any thickness of a DLC-coating, the adhesion obtained is at least as good as that of a chemical primer (such as the 2 DEF from Mitsubishi) under both dry and wet conditions.

Example 2

[0093] A similar BOPET film to the one used in Example 1 was coated with similar thin DLC coatings on one and two sides, as described in Table 2. OTR was measured as cc/m.sup.2/day/atm at 23 C. and 50% RH, by the same method as in Example 1. The DLC-coated films were subsequently laminated into packaging material structures including a paperboard with an outer LDPE layer, by means of a bonding layer of 15 g/m.sup.2 of LDPE, and by being further coated on the opposite side of the film with an inside layer of a blend of LDPE and mLLDPE at 25 g/m.sup.2. The OTR was measured on the laminated packaging material by the same method as described previously.

[0094] Subsequently, the laminated packaging materials were reformed into 1000 ml standard Tetra Brik Aseptic packaging containers, on which the total oxygen transmission was further measured, by a Mocon 1000 equipment at 23 C. and 50% RH.

TABLE-US-00002 Thickness Thickness OTR DLC 1 DLC 2 OTR packaging OTR Test coating coating Film material Package ID Film structure (nm) (nm) (mean) (mean) (mean) A /BOPET/DLC2/ 3.4 21.8 A /DLC1/BOPET/DLC2/ 11.9 3.4 1.1 1.6 0.037 B /BOPET/DLC2/ 3.4 19.3 B /DLC1/BOPET/DLC2/ 3.5 3.4 10.5 1.8 0.027

[0095] Very surprisingly, it was found that when measured on laminated packaging material, and on packages from the packaging material, the oxygen barrier properties were on the same level or even improved by the film of Test B, although the film in Test B was coated with only two very thin DLC coatings, while in Test A, one of the coatings was thicker and actually intended for providing the resulting oxygen barrier properties of the film. By the measurements on the barrier-coated films, the film of Test A was indeed better, but when laminated into a final laminated packaging material structure, and used in a packaging container, both the two films were performing very well, and the film of Test B was even performing better than the film of Test A.

[0096] Thus, by the DLC-coated barrier films described above, high-integrity packaging laminates are provided, which have maintained excellent adhesion between layers also when used in liquid packaging, i.e. at subjecting the packaging material to wet conditions, and which may consequently protect other layers of the laminate from deterioration, in order to provide as good laminated material properties as possible. Since the DLC coatings provide both goodoxygen barrier properties and water vapour barrier properties, it is a highly valuable type of barrier coating to be used in carton package laminates for liquid food products.

[0097] Further, relating to the attached figures:

[0098] In FIG. 1a, there is shown, in cross-section, a first embodiment of a laminated packaging material, 10, of the invention. It comprises a barrier film 11 having a substrate layer 11a of a polymer film having a surface of PET or PA, in this case an oriented PET (BOPET) film having a thickness of 12 m, wherein the substrate layer is coated with an, amorphous DLC coating 11b, by means of a plasma enhanced chemical vapour deposition, PECVD, coating, in order to improve the oxygen barrier (decrease the OTR value) of the barrier film. The vapour deposited coating 11b is a hydrogenated carbon coating (C:H) which is evenly deposited to a substantially transparent coating. The thickness of the DLC coating is 20 to 40 m. On its other side, opposite to the DLC barrier coating, the film substrate is coated with a thin layer of an adhesion-promoting primer 11c, such as 2-DEF, a priming composition from Mitsubishi Chemicals. The barrier film is laminated to a layer of a thermoplastic and heat sealable polymer layer on each side, 12,13, which may or may not be identical. The thermoplastic and heat sealable polymer layers are preferably polyolefin based polymers, and form the outermost, heat sealable layers of the laminate.

[0099] According to an alternative embodiment, the barrier film 11 as schematically shown in FIG. 1a, has instead, on its other side, opposite to the DLC barrier coating, been coated with a different thin layer of an adhesion-promoting, and/or barrier coating, layer 11c, of a further DLC PECVD coating.

[0100] In FIG. 1b, a similar barrier film 11 is provided, by a polymer film substrate 11a as in FIG. 1a, i.e. a BOPET film substrate, being vapour deposition coated on the coating side with a similar, amorphous DLC coating 11b, by means of plasma enhanced chemical vapour deposition coating, PECVD, in order to improve the oxygen barrier (decrease the OTR value). On its other side, opposite to the durable DLC barrier coating, the film substrate may be coated with a thin layer of an adhesion-promoting primer 11c of a DLC PECVD coating. The barrier film 11 is laminated to a further identical or similar barrier film 11; 11d, by means of an interjacent bonding layer 16 of a thermoplastic polymer, such as a polyolefin or modified polyolefin layer, such as a layer of LLDPE or a multilayer configuration of several individually identical or different polyethylene layers. The intermediate bonding layer is thus bonding to the DLC coating surfaces of both barrier films 11; 11d. On each side the barrier film is laminated to a layer of a thermoplastic and heat sealable polymer layer 12,13. Thus, the outermost layers of thermoplastic and heat sealable polymer are each contacting the adhesion-promoting primer coatings 11c (optional), of a DLC primer coating of each of the barrier films 11; 11d. A possible alternative adhesion-promoting coating 11c could be a chemical primer coating of the type 2 DEF from Mitsubishi.

[0101] In a further embodiment not shown, the outermost layer of a thermoplastic and heat sealable polymer layer 12; 22; 32, which is to constitute the outside of a packaging container made of the laminated material, is applied onto a bulk layer 21;31, which is laminated and positioned between the double barrier film obtained above and the outermost layer 12, the double barrier film being the double structure in which the intermediate bonding layer is bonding together the DLC barrier coating surfaces 11b of two barrier films 11; 11d. The double barrier film may contain further DLC coatings 11c for barrier and/or for adhesion-promotion purposes.

[0102] In FIG. 2, a laminated packaging material 20 of the invention, for liquid carton packaging, is shown, in which the laminated material comprises a paperboard bulk layer 21, having a bending force of 320 mN, and further comprises an outer liquid tight and heat sealable layer 22 of polyolefin applied on the outside of the bulk layer 21, which side is to be directed towards the outside of a packaging container produced from the packaging laminate. The polyolefin of the outer layer 22 is a conventional low density polyethylene (LDPE) of a heat sealable quality, but may include further similar polymers, including LLDPEs. An innermost liquid tight and heat sealable layer 23 is arranged on the opposite side of the bulk layer 21, which is to be directed towards the inside of a packaging container produced from the packaging laminate, i.e. the layer 23 will be in direct contact with the packaged product. The thus innermost heat sealable layer 23, which is to form the strongest seals of a liquid packaging container made from the laminated packaging material, comprises one or more in combination of polyethylenes selected from the groups consisting of LDPE, linear low density polyethylene (LLDPE), and LLDPE produced by polymerising an ethylene monomer with a C4-C8, more preferably a C6-C8, alpha-olefin alkylene monomer in the presence of a metallocene catalyst, i.e. a so called metallocene-LLDPE (m-LLDPE).

[0103] The bulk layer 21 is laminated to a barrier film 28, comprising a substrate layer 24 of a polymer film, in this case an oriented PET film having a thickness of 12 m, which is coated on a first side with a layer of a thin PECVD vapour deposited layer of amorphous, DLC barrier material, 25, at a thickness of from from 2-50 nm, such as from 5 to 40 nm. On its second, opposite, side, the polymer film substrate is coated with an adhesion-promoting primer 27, in this case 2-DEF, a priming composition from Mitsubishi Chemicals. The first, DLC-coated, side of the thus barrier-coated film 24 is laminated to the bulk layer 21 by an intermediate layer 26 of bonding thermoplastic polymer or by a functionalised polyolefin-based adhesive polymer, in this example by a low density polyethylene (LDPE). The intermediate bonding layer 26 is formed by means of extrusion laminating the bulk layer and the durable barrier film to each other. The thickness of the intermediate bonding layer 26 is preferably from 7 to 20 m, more preferably from 12-18 m. Excellent adhesion will be obtained between these layers, providing good integrity of the laminated material, in that the PECVD-coated DLC barrier coating is containing substantial amounts of carbon material, which exhibits good adhesion compatibility with organic polymers, such as polyolefins, such as in particular polyethylene and polyethylene-based co-polymers. The innermost heat sealable layer 23 consists of two or several part-layers of the same or different kinds of LDPE or LLDPE or blends thereof and has likewise good adhesion and integrity with the adjacent primer-coated side of the barrier film.

[0104] In FIG. 3, a laminated packaging material 30 of the invention, for liquid carton packaging, is shown, in which the laminated material comprises a paperboard bulk layer 31, having a bending force of 320 mN, and further comprises an outer liquid tight and heat sealable layer 32 of polyolefin applied on the outside of the bulk layer 31, which side is to be directed towards the outside of a packaging container produced from the packaging laminate. The polyolefin of the outer layer 32 is a conventional low density polyethylene (LDPE) of a heat sealable quality, but may include further similar polymers, including LLDPEs. An innermost liquid tight and heat sealable layer 33 is arranged on the opposite side of the bulk layer 31, which is to be directed towards the inside of a packaging container produced from the packaging laminate, i.e. the layer 33 will be in direct contact with the packaged product. The thus innermost heat sealable layer 33, which is to form the strongest seals of a liquid packaging container made from the laminated packaging material, comprises one or more in combination of polyethylenes selected from the groups consisting of LDPE, linear low density polyethylene (LLDPE), and LLDPE produced by polymerising an ethylene monomer with a C4-C8, more preferably a C6-C8, alpha-olefin alkylene monomer in the presence of a metallocene catalyst, i.e. a so called metallocene-LLDPE (m-LLDPE).

[0105] The bulk layer 31 is laminated to a barrier film 38, comprising a substrate layer 34 of a polymer film, in this case an oriented PET film having a thickness of 12 m, which is coated on a first side with a layer of a thin PECVD vapour deposited layer of amorphous, DLC barrier material, 35a, at a thickness of from from 2-50 nm, such as from 5 to 40 nm, such as from 10 to 40 nm. On its second, opposite, side, the polymer film substrate is coated with a second amorphous DLC coating 35b. The second amorphous DLC coating may add barrier properties too, but can also act merely as an adhesion promoting primer coating, and may then have a thickness as low as 2-4 nm. The first, DLC-coated, side of the thus barrier-coated film 34 is laminated to the bulk layer 31 by an intermediate layer 36 of bonding thermoplastic polymer or by a functionalised polyolefin-based adhesive polymer, in this example by a low density polyethylene (LDPE). The intermediate bonding layer 36 is formed by means of extrusion laminating the bulk layer and the durable barrier film to each other. The thickness of the intermediate bonding layer 36 is preferably from 7 to 20 m, more preferably from 12-18 m. The innermost heat sealable layer 33 may consist of two or several part-layers of the same or different kinds of LDPE or LLDPE or blends thereof. Excellent adhesion will be obtained between these layers on the inside of the bulk layer 31, providing good integrity of the laminated material, in that the PECVD-coated DLC barrier coating is containing substantial amounts of carbon material, which exhibits good adhesion compatibility with organic polymers, such as polyolefins, such as in particular polyethylene and polyethylene-based co-polymers.

[0106] In FIG. 4, the lamination process 40 is shown, for the manufacturing of the packaging laminate 20; 30, of FIG. 2, and FIG. 3, respectively, wherein the bulk layer 41 is laminated to the barrier film 28; 38; 43 by extruding an intermediate bonding layer of LDPE 44 from an extrusion station 45 and pressing together in a roller nip 46. The barrier film 28; 38; 43 has an amorphous DLC barrier coating, deposited on the surface of the polymer film substrate, whereby the DLC coating is to be directed towards the bulk layer when laminated at the lamination station 46. Subsequently, the laminated paper bulk and barrier film passes a second extruder feedblock 47-2 and a lamination nip 47-1, where an innermost heat sealable layer 23; 33; 47-3 is coated onto the barrier-film side of the paper-film laminate forwarded from 46. Finally, the laminate, including an innermost heat sealable layer 47-3, passes a third extruder feedblock 48-2 and a lamination nip 48-1, where an outermost heat sealable layer of LDPE 22; 32; 48-3 is coated onto the outer side of the paper layer. This latter step may also be performed as a first extrusion coating operation before lamination at 46, according to an alternative embodiment. The finished packaging laminate 49 is finally wound onto a storage reel, not shown.

[0107] FIG. 5a shows an embodiment of a packaging container 50a produced from the packaging laminate 20 according to the invention. The packaging container is particularly suitable for beverages, sauces, soups or the like. Typically, such a package has a volume of about 100 to 1000 ml. It may be of any configuration, but is preferably brick-shaped, having longitudinal and transversal seals 51a and 52a, respectively, and optionally an opening device 53. In another embodiment, not shown, the packaging container may be shaped as a wedge. In order to obtain such a wedge-shape, only the bottom part of the package is fold formed such that the transversal heat seal of the bottom is hidden under the triangular corner flaps, which are folded and sealed against the bottom of the package. The top section transversal seal is left unfolded. In this way the half-folded packaging container is still is easy to handle and dimensionally stable when put on a shelf in the food store or on a table or the like.

[0108] FIG. 5b shows an alternative, preferred example of a packaging container 50b produced from an alternative packaging laminate 20 according to the invention. The alternative packaging laminate is thinner by having a thinner paper bulk layer 21, and thus it is not dimensionally stable enough to form a cuboid, parallellepipedic or wedge-shaped packaging container, and is not fold formed after transversal sealing 52b. It will thus remain a pillow-shaped pouch-like container and be distributed and sold in this form. Also packaging materials of the type described in connection with FIG. 1 b, are particularly suitable for such pouch packages for liquid food and beverage.

[0109] FIG. 5c shows a gable top package 50c, which is fold-formed from a pre-cut sheet or blank, from the laminated packaging material comprising a bulk layer of paperboard and the durable barrier film of the invention. Also flat top packages may be formed from similar blanks of material.

[0110] FIG. 5d shows a bottle-like package 50d, which is a combination of a sleeve 54 formed from a pre-cut blanks of the laminated packaging material of the invention, and a top 55, which is formed by injection moulding plastics in combination with an opening device such as a screw cork or the like. This type of packages are for example marketed under the trade names of Tetra Top and Tetra Evero. Those particular packages are formed by attaching the moulded top 55 with an opening device attached in a closed position, to a tubular sleeve 54 of the laminated packaging material, sterilizing the thus formed bottle-top capsule, filling it with the food product and finally fold-forming the bottom of the package and sealing it.

[0111] FIG. 6 shows the principle as described in the introduction of the present application, i.e. a web of packaging material is formed into a tube 61 by the longitudinal edges 62 of the web being united to one another in an overlap joint 63. The tube is filled 64 with the intended liquid food product and is divided into individual packages by repeated transversal seals 65 of the tube at a pre-determined distance from one another below the level of the filled contents in the tube. The packages 66 are separated by incisions in the transversal seals and are given the desired geometric configuration by fold formation along prepared crease lines in the material.

[0112] We have thus seen that the laminated packaging material of the invention, enable the providing of packaging containers with good integrity properties also under wet conditions, i.e. for the packaging of liquid or wet food products with long shelf life.

[0113] The invention is not limited by the embodiments shown and described above, but may be varied within the scope of the claims.