Multilayer sheet-like packaging material for producing sealed packages

Abstract

A multilayer sheet-like packaging material (M) for producing sealed packages (1) of pourable food products comprises: at least one base layer (10) for imparting stiffness; a plurality of laminate layers (11) applied to both sides of the base layer (10) and covering both sides of the base layer (10); a pre-laminated opening (12) formed by a through slot provided in the base layer (10) and covered by one or more of the laminated layers (11), the pre-laminated opening (12) being configured to receive an opening device for pouring pourable food products; a plurality of crease lines (15) configured to define an edge between two adjacent walls of the sealed package of the packaging material (M) wherein the pre-laminated opening (12) does not intersect any of the crease lines (15) and includes an outer edge that is arcuate to define a first portion of a first circumference.

Description

Technical Field

[0001] The present invention relates to a multi-layer packaging material for producing a hermetically sealed package for pourable foods.

[0002] As is well known, many pourable foods, such as fruit juices, UHT (Ultra High Temperature treated) milk, wine, tomato ketchup, etc., are sold in packages made of sterilizable packaging materials. A typical example is the parallelepiped-shaped package for liquid or pourable foods called Tetra Brik Aseptic (registered trademark), which is made by folding and sealing a laminated strip of packaging material. The packaging material has a multi-layer structure, including a base layer (such as paper), which is covered on both sides with layers of heat-sealable plastic material (such as polyethylene). For aseptic packaging for long-term storage of products (such as UHT milk), the packaging material also includes a layer of oxygen barrier material, such as aluminum foil, which is superimposed on the heat-sealable plastic material layer and is in turn covered by another heat-sealable plastic material layer, which forms the inner surface of the package that finally contacts the food. Such packages are usually produced on fully automatic packaging machines, where a continuous tube is formed from a roll-fed packaging material; the roll of packaging material is sterilized on the packaging machine, for example by applying a chemical sterilizing agent (such as hydrogen peroxide solution), which is removed from the surface of the packaging material after sterilization is complete, for example by heating and evaporation; then the so-sterilized roll is kept in a closed aseptic environment and longitudinally folded and sealed to form a tube, which is fed vertically. To complete the forming operation, the sterilized or aseptically treated food is loaded into the tube, which is then sealed and subsequently cut along equidistant cross-sections; the pillow-shaped packages thus obtained are then mechanically folded to form the corresponding finished packages. Alternatively, the packaging material can be cut into blanks, formed into packages on a forming mandrel, and then the food is loaded into the packages and sealed. An example of such a package is the so-called "gable-top" package, which is commercially known as Tetra Rex (registered trademark).

[0003] To open the above-mentioned packages, these packages are usually provided with a detachable part, which is partially separated from the rest of the packaging material by an opening device to release a pouring opening through which the product is poured out. The detachable part is formed on the packaging material before folding and sealing the packaging material to form the finished package.

[0004] The detachable part usually includes a so-called "pre-laminated" hole, i.e., a hole formed only in the base layer of the packaging material, which is covered by the heat-sealable plastic material layer and the barrier material layer when the material is laminated, and the heat-sealable plastic material layer and the barrier material layer adhere to each other at the hole. The "pre-laminated" holes are usually circular, but other shapes can be foreseen, such as those disclosed in patent documents EP2287082A1 and EP3260386A1 under the trade name Tetra Laval.

[0005] Typically, the package includes an opening device, which includes: a frame that defines a nozzle and is mounted around a detachable part of the package; a detachable lid that is screwed onto the outside of the frame to close the nozzle; and a generally tubular cylindrical cutter that is screwed inside the frame and is configured to tear the detachable part during the first opening of the package. Typically, such an opening device is made of plastic material.

[0006] Recently, the focus of research has been on reducing plastic consumption to improve the sustainability of packaging.

[0007] Specifically, the focus of research has been on providing a reusable opening device that can be used multiple times for several packages. In this case, the package does not come with an opening device applied to it. The end consumer needs to first apply the opening device to the package and then pour out the liquid product. Once the package is empty, the opening device is removed to be used again for another package.

[0008] Therefore, there is a need to provide a package suitable for receiving a reusable opening device. Specifically, there is a need to provide a package with a pre-laminated opening that allows the reusable opening device to be received tightly so that during the pouring of the liquid product, no liquid product drips onto the package.

[0009] In addition, there is a need to provide a package with a pre-laminated opening for receiving a reusable opening device, where the pre-laminated opening can be cleanly cut by the cutter of the opening device without fraying that would interfere with the pouring of the food product.

[0010] In addition, there is a need to provide a package with a pre-laminated opening for receiving a reusable opening device, where the pre-laminated opening does not accidentally break during the storage and transportation of the package. Summary of the Invention

[0011] Therefore, an object of the present invention is to provide a multi-layer sheet packaging material for producing a sealed package for pourable food products, which overcomes one or more of the above disadvantages. In addition, an object of the present invention is to provide a sealed package for pourable food products, which overcomes one or more of the above disadvantages.

[0012] These objects are fully achieved by the multi-layer sheet packaging material and the sealed package according to the appended claims. Brief Description of the Drawings

[0013] Two non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which:

[0014] A cross-sectional view of a multi-layer sheet packaging material according to the present disclosure is shown;

[0015] Figure 2A Shows a sealed package according to an embodiment of the present disclosure;

[0016] Figure 2B Shows a multilayer sheet packaging material for producing Figure 2A the sealed package;

[0017] Figure 2C Shows Figure 2B an enlarged detail;

[0018] Figure 3A Shows a sealed package according to an embodiment of the present disclosure;

[0019] Figure 3B Shows a multilayer sheet packaging material for producing Figure 3A the sealed package;

[0020] Figure 3C Shows Figure 3B an enlarged detail;

[0021] Figure 4A Shows a sealed package according to an embodiment of the present disclosure;

[0022] Figure 4B Shows a multilayer sheet packaging material for producing Figure 4A the sealed package;

[0023] Figure 4C Shows Figure 4B an enlarged detail;

[0024] Figure 5A Shows a sealed package according to an embodiment of the present disclosure;

[0025] Figure 5B Shows a multilayer sheet packaging material for producing Figure 4A the sealed package;

[0026] Figure 5C Shows Figure 5B an enlarged detail;

[0027] Figure 6A Shows a sealed package according to an embodiment of the present disclosure;

[0028] Figure 6B Shows a multilayer sheet packaging material for producing Figure 6A the sealed package;

[0029] Figure 6C Shows Figure 6B an enlarged detail;

[0030] Figures 7 - 10Shows corresponding details of a multi-layer sheet packaging material according to a further embodiment of the present disclosure. Detailed Description

[0031] The numeral 1 denotes a sealed package for pourable foodstuffs in general, which is made of a multi-layer sheet packaging material M and is designed to receive an opening device for pouring the pourable foodstuffs. Specifically, the sealed package 1 is designed to receive a reusable opening device on the top or top wall of the package 1. Preferably, the opening device comprises a cutter which is configured to tear a pre-laminated opening 12 to define a pouring opening.

[0032] In a non-limiting example, the opening device is of the type described in EP3260386A1. It should also be noted that other opening devices may be used. Specifically, a reusable opening device may be used, which can be applied by the end consumer to the sealed package and removed once the package is empty for application to another package.

[0033] The package 1 can be a parallelepiped or prismatic package, or a "gable top" package. According to a non-limiting embodiment, the package 1 has the parallelepiped shape described in WO2015 / 169656A1. Referring Figure 2A 、 3A 、4A, 5A, 6A, the package 1 comprises a quadrilateral (specifically, rectangular or square) top wall 5, a quadrilateral (specifically, rectangular or square) bottom wall 6, and four side walls 7 which extend between the top wall 5 and the bottom wall 6. The opening device is configured to be applied to the top wall 5.

[0034] Preferably, the package 1 comprises a transverse seal line 8 across the top wall 5 and another transverse seal line (not visible in the figure) across the bottom wall 6. Preferably, the package 1 comprises longitudinal seal lines 9 perpendicular to the transverse seal line 8.

[0035] The packaging material M for producing the sealed package 1 has a multi-layer structure which comprises at least one base layer 10 (which is made of paper, for example) configured to impart stiffness, and a plurality of laminated layers 11 are applied to both sides of the base layer 10 and cover both sides of the base layer 10.

[0036] In the example shown, the laminated layer 11 comprises a layer 11a made of an oxygen barrier material (such as aluminium foil), and a plurality of heat-sealable plastic layers 11b covering both sides of the base layer 10 and the layer 11a. In other words, the packaging material comprises, starting from the side which will ultimately form the inside of the package 1, in sequence, a heat-sealable plastic layer 11b, an oxygen barrier material layer 11a, another heat-sealable plastic layer 11b, the base layer 10 and another heat-sealable plastic layer 11b.

[0037] In use, the inner heat-sealable plastic material layer 11b in contact with food can be made of, for example, a strong, particularly highly stretchable, metallocene-catalyzed, low linear density (LLD) polyethylene.

[0038] Typically, the heat-sealable plastic material layer 11b is laminated to the base layer 10 and / or the oxygen barrier material layer 11a in a molten state, and then cooled.

[0039] As a possible alternative, at least the inner plastic material layer 11b can be provided as prefabricated films, which are laminated onto the base layer 10 and / or the oxygen barrier material layer 11a; this technique allows reducing any risk of forming holes or cracks at or around the removable part during the forming operation of the sealed package 1.

[0040] Preferably, the plurality of laminated layers 11 includes at least a first laminated layer applied to the first side of the base layer 10 and a second laminated layer 12 applied to the second side of the base layer 11. For example, the first laminated layer can include the oxygen barrier layer 11a and / or a heat-sealable plastic material layer 11b; the second laminated layer can include another heat-sealable plastic material layer 11b. At the pre-laminated opening 12, the first laminated layer and the second laminated layer are sealed together.

[0041] Figure 2B 、 3B Figures 4A, 4B, 5B, 6B show the basic unit of the packaging material M for producing the package 1, which can be a pre-cut blank or a part of a roll of packaging material M including continuous units.

[0042] In the first case, the basic unit is folded on a known folding spindle (not shown), filled with food, and sealed at the top to form the package 1. In the second case, a roll of packaging material including continuous basic units is folded into a cylinder to form a vertical tube; continuously filled with food; transversely sealed and cut into basic units, and then folded to form the corresponding package 1.

[0043] The packaging material M includes a plurality of folding lines (or crease lines) 15, which are used to define the edge between two adjacent walls of the sealed package 1 formed by folding and sealing the packaging material M. Specifically, each basic unit of the packaging material M has a crease pattern, that is, a plurality of folding lines (or crease lines) 15, along which the packaging material M can be folded to form the finished package 1. Preferably, the folding lines 15 are obtained by squeezing the base layer 10 between a pair of tools, such that the base layer 10 is locally deformed, and then coupling the base layer 10 with the laminated layer 11.

[0044] In the illustrated example, the crease pattern includes a first fold line extending horizontally, a second fold line extending vertically (i.e., perpendicular to the first fold line), and a third fold line inclined (at an acute angle) with respect to the first and second fold lines. The fold lines 15 define the edges between the respective walls of the formed package 1 in a known manner.

[0045] The packaging material M further includes a pre-laminated opening 12 formed by a through slot provided in the base layer 10 and covered by one or more of the laminating layers 11 in the laminating layer 11. The pre-laminated opening 12 is configured to receive an opening device (in particular a reusable opening device) for pouring out a pourable food product from the package 1. The pre-laminated opening 12 is configured to be torn by a cutter of the opening device, thereby defining a pouring opening. Specifically, under the action of the cutter of the opening device, a detachable portion can be partially separated from the rest of the packaging material M, thereby defining a pourable opening.

[0046] Preferably, the pre-laminated opening 12 is formed on the packaging material M before folding and sealing the packaging material M to form the package 1. Preferably, the pre-laminated opening 12 does not intersect any of the fold lines 15. In other words, the fold lines 15 are at a distance from the pre-laminated opening 12. Thus, in the formed package 1, the pre-laminated opening 12 is completely contained in the top wall 5 and does not extend into any of the side walls 7.

[0047] Preferably, the pre-laminated opening 12 includes an outer edge 120 that extends between a first end 120a and a second end 120b spaced apart from the first end 120a. The outer edge 120 is arcuate (or curved) to define a first portion C11 of a first circumference C1.

[0048] The curved arcuate shape of the outer edge of the pre-laminated opening helps to provide guidance for the rotation of the cutter of the opening device during insertion of the opening device into the opening, thereby defining a pouring hole. By the rotation of the cutter, the rupture of the pre-laminated opening can be precisely controlled such that the opening device can adhere tightly to the packaging material M. In addition, the fact that the first end 120a is spaced apart from the second end 120b such that the outer edge only defines a portion of the circumference helps to prevent a small portion of the packaging material M from falling into the container during insertion of the opening device.

[0049] In one or more embodiments, as Figure 2C 、 3C, as shown in 4C, 5C, 6C, and 10, the first end 120a and the second end 120b of the outer edge 120 are arranged along the first circumference C1. Accordingly, the first portion C11 of the first circumference C1 is defined between (or extends between) the first end 120a and the second end 120b of the outer edge 120, that is, extends from the first end 120a of the outer edge 120 to the second end 120b.

[0050] In other embodiments, as Figure 7 , 8 , as shown in 9, the first end 120a and / or the second end 120b of the outer edge 120 are located outside the first circumference C1. In these cases, the outer edge 120 extends partially along the first circumference C1 and partially outside the first circumference C1.

[0051] Preferably, the multi-layer sheet packaging material M includes a weakening line 13 in the base layer 10. Preferably, the weakening line 13 extends from the pre-lamination opening 12. Specifically, the weakening line 13 extends from the first end 120a and / or the second end 120b of the outer edge 120 of the pre-lamination opening 12.

[0052] Preferably, the weakening line 13 extends at least partially along the second portion C12 of the first circumference C1. Preferably, the first portion C11 of the first circumference C1 (including the outer edge 120) does not overlap with the second portion C12 of the first circumference C1 (including the weakening line 13).

[0053] According to some embodiments, the first portion C11 of the first circumference C1 (including the outer edge 120) is longer than the second portion C12 of the first circumference C1 (including the weakening line 13). According to some other embodiments, the first portion C11 of the first circumference C1 (including the outer edge 120) is shorter than the second portion C12 of the first circumference C1 (including the weakening line 13).

[0054] According to some non-limiting embodiments, the first circumference C1 includes: a first portion C11, which has the outer edge 120 of the pre-lamination opening 12; a second portion, which has the weakening line 13; and a third portion, which has neither the outer edge 120 of the pre-lamination opening 12 nor the weakening line 13.

[0055] According to Figure 2C and Figure 6C In some non-limiting embodiments shown, the base layer 10 is cut at least partially along the weakening line 13. Specifically, the depth of the weakening line 13 in the base layer 10 is less than the thickness of the base layer 10. Specifically, the base layer 10 is cut dot by dot along the weakening line 13.

[0056] According to Figure 3C , Figure 7 , Figure 9In some non - limiting embodiments shown, the base layer 10 forms a crease along the weakening line 13. Preferably, the crease defining the weakening line 13 is obtained by squeezing the base layer 10 between a pair of tools such that the base layer 10 is locally deformed, and then coupling the base layer 10 to the laminate layer 11.

[0057] The weakening line 13 provides guidance for the opening device when the package 1 is first opened. Specifically, the opening device is inserted through the pre - laminated opening 12 such that the laminate layer 11 covering the pre - laminated opening 12 ruptures, thereby forming a pouring hole. Additionally, the pouring hole is enlarged by rupturing the base layer 10 along the weakening line 13. In this way, the formation of the pouring hole is finely controlled, and the final size and shape of the pouring hole are precisely predictable. Accordingly, the opening device will adhere tightly to the packaging material M.

[0058] According to Figure 2C , 3C , one or more of the embodiments shown in FIGS. 4C, 5C, 6C, 7, 8, 9, the pre - laminated opening 12 includes an arcuate inner edge extending along a second circumference C2. The second circumference C2 is smaller than the first circumference C1. The pre - laminated opening 12 is at least partially defined by the inner edge of the second circumference C2 and the outer edge 120 of the first circumference C1.

[0059] Preferably, the first circumference C1 and the second circumference C2 have a common center. Accordingly, the inner edge of the second circumference C2 and the outer edge 120 of the first circumference C1 are parallel to each other. In other embodiments, the first circumference C1 and the second circumference C2 have different centers such that the inner edge of the second circumference C2 and the outer edge 120 of the first circumference C1 are not parallel to each other.

[0060] Specifically, in these embodiments, the pre - laminated opening 12 is C - shaped. Accordingly, the pre - laminated opening 12 partially surrounds the central portion of the base layer. The C - shape particularly helps to enhance the robustness of the pre - laminated opening 12 to avoid its accidental rupture during transportation.

[0061] According to Figure 10 an alternative embodiment shown, the pre - laminated opening 12 is defined by an arcuate outer edge 120 and a line inside the first circumference C1 connecting a first end 120a and a second end 120b, the arcuate outer edge 120 extending from the first end 120a to the second end 120b along a first portion C11 of the first circumference C1. Preferably, the weakening line 13 extends along the first circumference C1 in a second portion C12 without the outer edge 120.

[0062] According to one or more embodiments, the packaging material M includes an additional pre-laminated opening 14, which (not shown in the figure) is formed by an additional through slot provided in the base layer 10 and covered by one or more of the laminated layers 11. The additional pre-laminated opening is configured to receive a straw connected to an opening device. The straw is configured to allow air to leave the package 1 during the pouring of the liquid food through the pre-laminated hole and the opening device connected to the pre-laminated hole. Preferably, the shape of the additional pre-laminated opening is circular. Preferably, the pre-laminated opening 12 and the additional pre-laminated opening are located in an area of the sheet material not traversed by any folding line 15; thus, both the pre-laminated opening 12 and the additional pre-laminated opening will be included in the top wall 5 of the formed package 1.

[0063] According to Figure 8 In the embodiment shown, the packaging material M includes another pre-laminated opening 16, which is formed by another through slot provided in the base layer 10 and covered by one or more of the laminated layers 11. This another pre-laminated opening 16 cooperates with the pre-laminated opening 12 to surround the central portion of the base layer 10 (which helps to enhance the robustness of the pre-laminated opening 12). Preferably, the pre-laminated opening 12 and this another pre-laminated opening are located within an area of the sheet material not traversed by any folding line 15; thus, both the pre-laminated opening 12 and the additional pre-laminated opening will be included in the top wall 5 of the formed package 1. It is noted that this another pre-laminated opening 16 can be provided in combination with the additional pre-laminated opening configured to receive a straw, or as a supplement to the additional pre-laminated opening.

Claims

1. A multi-layer sheet packaging material (M) for producing a hermetically sealed package (1) for pourable food, said packaging material (M) comprising: At least one base layer (10) for imparting stiffness; A plurality of laminated layers (11) applied to both sides of said base layer (10) and covering both sides of said base layer (10); A pre-laminated opening (12) formed by a through slot provided in said base layer (10) and covered by one or more of said laminated layers (11), said pre-laminated opening (12) being configured to receive an opening device for pouring out said pourable food; A plurality of crease lines (15) configured to define an edge between two adjacent walls of the hermetically sealed package formed by folding and sealing said packaging material (M), wherein said pre-laminated opening (12) does not intersect any of said folding lines (15), Characterized in that said pre-laminated opening (12) comprises an outer edge (120) extending between a first end (120a) and a second end (120B) spaced apart from said first end (120a), wherein said outer edge (120) is arcuate to define a first portion (C11) of a first circumference (C1).

2. The multi-layer sheet packaging material (M) according to claim 1, wherein said first end (120a) and said second end (120b) of said outer edge (120) are positioned along said first circumference such that said first portion of said first circumference is defined as extending from said first end (120a) to said second end (120b) of said outer edge (120).

3. The multi-layer sheet packaging material (M) according to claim 1 or 2, further comprising a weakening line (13) in said base layer (10), wherein said weakening line (13) extends from said pre-laminated opening (12).

4. The multi-layer sheet packaging material (M) according to claim 3, wherein said weakening line (13) extends from said first end (120a) and / or said second end (120a) of said outer edge (120) of said pre-laminated opening (12).

5. The multi-layer sheet packaging material (M) according to claim 3 or 4, wherein said weakening line (13) extends along a second portion (C12) of said first circumference (C1).

6. The multi-layer sheet packaging material (M) according to claim 5, wherein said first portion (C11) of said first circumference (C1) is as long as or longer than said second portion (C12) of said first circumference (C1).

7. The multi-layer sheet packaging material (M) according to claim 5 or 6, wherein the first circumference (C1) comprises: Said first portion (C11), which has said outer edge (120) of said pre-laminated opening (12); said second portion (120), which has said weakening line (13); and a third portion, which has neither said outer edge (120) of said pre-laminated opening (12) nor said weakening line (13).

8. The multi-layer sheet packaging material (M) according to any one of claims 3 to 7, wherein the base layer (10) is at least partially cut along the weakening line (13).

9. The multi-layer sheet packaging material (M) according to claim 8, wherein the depth of the weakening line (13) in the base layer (10) is less than the thickness of the base layer (10).

10. The multi-layer sheet packaging material (M) according to claim 8 or 9, wherein the base layer (10) is cut in a dot pattern along the weakening line (13).

11. The multi-layer sheet packaging material (M) according to any one of claims 3 to 10, wherein the base layer (10) forms a crease along the weakening line (13).

12. The multi-layer sheet packaging material (M) according to any one of the preceding claims, wherein the pre-laminated opening (12) includes an arcuate inner edge that extends along a second circumference that is less than the first circumference.

13. The multi-layer sheet packaging material (M) according to claim 12, wherein the pre-laminated opening (12) is C-shaped.

14. The multilayer sheet packaging material (M) according to any one of the preceding claims, wherein the plurality of laminated layers (11) includes a first laminated layer applied to the first side of the base layer (10) and a second laminated layer (12) applied to the second side of the base layer (11), wherein, At the pre-laminated opening (12), the first lamination layer and the second lamination layer are sealed together.

15. A sealed package (1) for a pourable food product, formed by folding and sealing a packaging material (M) according to any one of the preceding claims and configured to receive an opening device for pouring the pourable food product, wherein the pre-laminated opening (12) is configured to be torn by a cutter of the opening device to define a pouring opening.

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