Packaging material and method for manufacturing the same

Abstract

A packaging material is provided, comprising a core layer (201, 201', 401, 501); an outermost layer (202, 202', 402, 502) arranged to face the outside of a packaging container made of the packaging material (200, 200', 400, 500); and an innermost layer (203, 203', 403, 503) arranged to face the inside of the packaging container. The outermost layer (202, 202', 402, 502) and the innermost layer (203, 203', 403, 503) are laminated to the core layer (201, 201', 401, 501). The laminated packaging material (200, 200', 400, 500) further comprises locally distributed portions (204, 204', 404, 504) of heat-sealable material arranged on the innermost layer (200, 200', 400, 500).

Description

Technical Field

[0001] The present invention relates to a packaging material, in particular to a laminated packaging material, and a method for producing the laminated packaging material.

[0002] Furthermore, the invention relates to a packaging container made of the laminated packaging material. Background Art

[0003] Carton packaging containers for liquid foods are well known. For example, in many parts of the world, (Tetra ) packaging containers to hold milk, juice and other beverages. There are many reasons why carton-based packaging has gained popularity. The environmental benefits of packaging, such as the fact that the packaging is largely made of renewable materials, and the efficient logistics of brick-shaped packaging are some of the reasons why today's consumers choose carton-based packaging over plastic bottles. Other reasons for the popularity of carton-based packaging are that the packaging machines for producing packaging containers are robust and cost-effective compared to other alternatives, and the overall cost of running a carton-based packaging machine is very competitive.

[0004] Packaging containers for pourable foods need to have certain barrier properties so that the filled and unopened packaging container can be stored properly. The required shelf life and the type of barrier required depend on the type of food, the type of packaging material, the type of packaging container, the type of opening device of the packaging container, etc., and also on the sterility aspects and the expected storage conditions. Generally, a certain degree of oxygen barrier is required in all cases.

[0005] Packaging materials are produced by laminating multiple polymer layers onto a core material layer of a carton or paperboard. The polymer layer protects the core material layer, which is usually made of a carton or paperboard, from the liquid contents of the resulting packaging container and from the humid external environment. As packaging material manufacturing processes improve in speed and quality, and as polymer layers improve and are developed to be laminated into thinner layers, the total amount of polymer material used for the laminated layers of the packaging material can be reduced. However, when forming and filling a single packaging container, the internal polymer layer is also used to seal the packaging material. Therefore, the general desire to reduce the thickness of the polymer layer inside the packaging material conflicts with the requirement to have a sufficiently thick polymer layer to ensure proper sealing of the packaging material.

[0006] Therefore, there is a need for an improved packaging material that ensures a secure seal while still allowing for a reduction in the overall polymer layer material. Summary of the invention

[0007] It is an object of the present invention to at least partially overcome one or more of the above-mentioned limitations of the prior art.

[0008] To solve these purposes, a packaging material for liquid food is provided. The packaging material comprises a core layer, an outermost layer arranged to face the outside of a packaging container made of the packaging material, and an innermost layer arranged to face the inside of the packaging container, the outermost layer and the innermost layer being laminated to the core layer. The laminated packaging material further comprises a locally applied heat-sealable material portion arranged on the innermost layer.

[0009] The heat-sealable material portion may be arranged at a sealing area corresponding to the location of a transverse seal of the resulting packaging container.

[0010] The heat sealable material portion may be adhered to the innermost layer by means of a heat application process.

[0011] The heat application process may be an injection molding process, a sintering process, a welding process, a spraying process, an inkjet polymer printing process or a 3D printing process.

[0012] The heat sealable material portion may have a cross-section with a width that increases towards the innermost layer, ie towards its base at the substrate surface.

[0013] The heat sealable material portion may have a cross section that is triangular or truncated triangular in shape. Alternatively, the heat sealable material portion may have a cross section that is circular or semicircular in shape at the top.

[0014] The portion of heat sealable material may have a cross-section that is asymmetrically shaped.

[0015] The portion of heat-sealable material may be arranged to have a varying cross-section along the extension of the transverse sealing area.

[0016] The heat sealable material portion may have a cross section providing a higher amount of polymer material at a predetermined position along the extension of the transverse sealing area. In particular, such a cross section may have a wider base, i.e. an increasing width towards the innermost layer and / or a steeper inclination towards the apex or top of the cross section.

[0017] The heat-sealable portion may be applied only at portions along the extension of the transverse sealing area or along its entire extension.

[0018] The heat sealable material portion may have a closed cavity, ie be hollow inside.

[0019] The thickness of the heat-sealable material portion may be 2-50 μm, preferably 3-30 μm, for example 3-20 μm, or 5-20 μm, most preferably 5-15 μm.

[0020] The heat sealable material portion may be made of a thermoplastic material, such as a thermoplastic polymer.

[0021] The thermoplastic polymer may be selected from the group consisting of polyolefins and polyesters.

[0022] The thermoplastic polymer may be selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate (PET), polyethylene furanoate (PEF), polylactic acid polymer or copolymer (PLA), polyhydroxyalkanoate (PHA), and blends or copolymers of two or more thereof.

[0023] The thermoplastic polymer of the locally applied heat-sealable material portion can be selected from the group consisting of low density polyethylene LDPE, high density polyethylene HDPE, linear low density polyethylene LLDPE or single-site catalyzed linear low density polyethylene m-LLDPE, very low density polyethylene (VLDPE), ultra low density polyethylene (ULDPE) and blends and copolymers of two or more thereof.

[0024] The thermoplastic polymer may be a biodegradable polymer selected from the group consisting of polylactic acid polymers or copolymers (PLA), polyhydroxyalkanoates (PHA), cellulose or cellulose derivatives and blends or copolymers of two or more thereof. Examples of PHAs are, in particular, poly 3-hydroxybutyrate (PHB), polyhydroxyvalerate (PHV) and polyhydroxyhexanoate (PHH).

[0025] The heat-sealable material portion may be arranged along the entire extension of the transverse sealing area or only partially along the extension of the transverse sealing area.

[0026] The portion of heat-sealable material may be arranged to have a varying cross-section along the extension of the transverse sealing area.

[0027] The packaging material may further include a barrier layer arranged between the core layer and the innermost layer.

[0028] The barrier layer may be an aluminum foil or a metallized aluminum layer. The barrier layer may alternatively be a non-aluminum foil ("non-foil") barrier layer, such as a vapor deposited coating of an inorganic oxide, a metal oxide or diamond-like carbon (DLC), such as a dispersion coating of polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), starch or starch derivatives, cellulose or cellulose derivatives (e.g. micro / nanofibrillar cellulose), or for example a polymer barrier, such as polyamide or ethylene vinyl alcohol (EVOH).

[0029] The core layer may be a cellulose based material such as paper or paperboard.

[0030] According to a second aspect, a method for producing a packaging container using a laminated packaging material is provided. The method comprises the steps of laminating an innermost layer and an outermost layer to a core layer or providing a laminated packaging material having an innermost layer and an outermost layer laminated to a core layer, locally applying a heat-sealable material portion to the innermost layer, forming a packaging container with an open end from the packaging material, filling the packaging container through the open end, and heat-sealing the packaging container with the help of the heat-sealable material portion to form a closed packaging container.

[0031] Heat can be applied using an injection molding process, a sintering process, a welding process, a spraying process, an inkjet polymer printing process, a compression molding process or a 3D printing process. The preferred heat application process is injection molding, such as high pressure microinjection molding, inkjet polymer printing and 3D printing, because these processes allow the final geometry of the locally applied heat-sealable material portion to be shaped in a better manner. High pressure microinjection molding is the most preferred process because it achieves higher application speeds and may involve very small amounts of polymer, and is therefore suitable for high-speed packaging processes in filling and packaging machines.

[0032] The innermost layer may be a heat sealable polymer, preferably a thermoplastic polymer selected from polyolefins (eg polyethylene) and polyesters.

[0033] The innermost layer may be a heat sealable thermoplastic polymer selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate (PET), polyethylene furanoate (PEF), polylactic acid polymer or copolymer (PLA), polyhydroxyalkanoate (PHA) and blends or copolymers of two or more thereof.

[0034] The innermost layer may be a heat-sealable thermoplastic polymer selected from the group consisting of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyethylene furanoate (PEF) and any blend or copolymer of one or more thereof. The innermost layer may be a thermoplastic polymer selected from the group consisting of polyethylene (PE) or polyethylene terephthalate (PET), and the material of the heat-sealable material portion may be polyethylene (PE).

[0035] The thermoplastic polymer of the innermost layer and the thermoplastic polymer of the topically applied portion of heat-sealable material may be the same type of polymer or different types of polymer.

[0036] The innermost layer may comprise a thermoplastic polymer selected from the group consisting of low, medium and high density polyethylene (LDPE, MDPE, HDPE), linear low density polyethylene and single-site or metallocene-catalyzed linear low density polyethylene (LLDPE, m-LLDPE) and polypropylene (PP) and blends and copolymers of two or more thereof.

[0037] The material of the heat sealable material portion may include a thermoplastic polymer selected from the group consisting of high / medium density polyethylene (HDPE, MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE, m-LLDPE) and blends and copolymers of two or more thereof.

[0038] The thermoplastic polymer of the innermost layer may be selected from the group consisting of low density polyethylene LDPE, high density polyethylene HDPE, linear low density polyethylene LLDPE or single-site catalyzed linear low density polyethylene m-LLDPE and blends and copolymers of two or more thereof. The seal initiation temperature, i.e. softening temperature, such as Vicat point or glass transition temperature (Tg) of the thermoplastic polymer of the locally applied heat sealable material portion may be equal to or lower than the corresponding seal initiation temperature of the thermoplastic polymer of the innermost layer. The seal initiation temperature of the thermoplastic polymer of the locally applied heat sealable material portion may be 4K, such as 5K, such as 10K lower than the corresponding or corresponding temperature of the innermost layer.

[0039] The melting temperature (Tm) of the thermoplastic polymer of the heat sealable material part that is locally applied can be equal to or lower than the corresponding melting temperature of the thermoplastic polymer of the innermost layer.The melting temperature of the thermoplastic polymer of the heat sealable material part that is locally applied can be lower than 4K of the melting temperature of the innermost layer, for example 5K, for example 10K.The heat sealable material part can be applied so that the cross section has the width increased towards the innermost layer.In one embodiment, the heat sealable material part that is locally applied has a triangular cross section or has a cross section of a truncated triangle shape.The triangle or truncated triangle cross section of the heat sealable material part that is locally applied provides the best heat sealing operation aspect the intensity of operating efficiency, used material amount and gained heat sealing joint.

[0040] The heat sealable material portion may have a cross section that is triangular or truncated triangular in shape. Alternatively, the heat sealable material portion may have a cross section that is circular or semicircular in shape at the top.

[0041] The portion of heat sealable material may have a cross-section that is asymmetrically shaped.

[0042] The portion of heat-sealable material may be arranged to have a varying cross-section along the extension of the transverse sealing area.

[0043] The heat sealable material portion may have a cross section providing a higher amount of polymer material at a predetermined position along the extension of the transverse sealing area. In particular, such a cross section may have a wider base, i.e. an increasing width towards the innermost layer and / or a steeper inclination towards the apex or top of the cross section.

[0044] The heat-sealable portion may be applied only at portions along the extension of the transverse sealing area or along its entire extension.

[0045] The heat-sealable material portion may have a closed cavity, ie have a hollow structure.

[0046] According to a third aspect, there is provided a packaging container made of a packaging material, the packaging material comprising a core layer and an outermost layer and an innermost layer laminated thereon. A heat sealable material portion is locally arranged on the innermost layer.

[0047] Other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0049] Figure 1 It is a schematic diagram of the principle of a packaging machine for continuous roll-fed packaging of liquid food;

[0050] Figure 2a to Figure 2b are cross-sectional views of packaging materials according to various embodiments;

[0051] Figure 3a is a plan view of a packaging material according to one embodiment;

[0052] Figure 3b Is Figure 3a An isometric view of a package formed of packaging material is shown;

[0053] Figures 4a to 4c shows three stages of an injection molding process for providing a portion of heat-sealable material on the innermost layer of a packaging material according to one embodiment;

[0054] Figure 5a to Figure 5c shows three stages of an injection molding process for providing a portion of heat-sealable material on the innermost layer of a packaging material according to one embodiment;

[0055] Figure 6 is a flow chart of a method for producing packaging material;

[0056] Figures 7a to 7d Shows Figure 4c and 5c Further alternatives for the mid-section;

[0057] Figure 8a shows a cross section of a prior art folded forming tube to be transversely sealed from a conventional laminated packaging material;

[0058] Figures 8b to 8cshows a variant of the cross section of a folded tube which, instead of having only a very thin layer of heat-sealable material on the inner side of the laminated packaging material, additionally has locally applied portions of heat-sealable material applied along at least some parts of the extension of the transverse seal area;

[0059] Fig. 9 shows the transverse sealing area viewed from above the inside of a web of flat packaging material; and

[0060] Fig.10 An isometric view is shown along the extension of a transverse seal area having a locally applied portion of heat-sealable material. DETAILED DESCRIPTION

[0061] from Figure 1 At the beginning, the basic principle of a packaging machine based on a roll-fed carton is shown. The packaging machine is configured for continuous packaging, for example of liquid foods, and forms a common technical concept for a variety of different packaging systems, such as the commercially successful Tetra Pak. ) packaging system. The packaging machine receives the continuous roll material (such as Figure 1 ) of the packaging material 100.

[0062] After the packaging material 100 is unrolled from the reel 110, its longitudinal side edges 101a-b are brought together to form a longitudinal seal LS, thereby also forming a continuous tube 140 of the packaging material 100. More specifically, the longitudinal side edges 101a-b are continuously attached to each other in an overlapping manner. The tube 140 is filled with the desired product (preferably liquid food) from the filling tube 150.

[0063] By forming the transverse seals TS at the ends of the tube 140 and cutting them off when the sealed portions are formed, a series of packages 160 are formed from the tube 140, each sealed portion representing an individual package 160. To form the packages 160, different forming tools may be used during the transverse sealing operation, or a separate forming process may be performed after the transverse sealing has been performed.

[0064] Alternatively, a blank-fed packaging machine is used. A blank is fed to the filling machine in the form of a pre-cut piece of packaging material, the two ends of which are welded together, thereby forming a folded and sealed tubular sleeve. The blank is erected into an open sleeve, then folded and sealed, thereby forming a closed top or bottom. Thereafter it is filled with the product and sealed and folded at the open end, thereby obtaining a filled packaging container.

[0065] Figure 2aA cross-section of a laminated packaging material 200 according to one embodiment is shown. It comprises a body layer or core layer 201, which may be a fiber-based material, such as a cellulose-based material. The body layer may comprise a cellulose-based material, such as paper or paperboard. The laminated packaging material 200 further comprises an outermost layer 202 on the outside of the body layer 201. Thus, the outermost layer 202 is configured to face the outside of the package 160 formed by the laminated packaging material 200. The outermost layer 202 is preferably a protective thermoplastic polymer layer, which may act as a liquid barrier and also have thermoplastic properties for heat sealing purposes. In addition, Figure 2a The laminated packaging material 200 in the embodiment includes an innermost layer 203 on the inner side of the main body layer or core layer 201. Therefore, the innermost layer 203 is configured to face the interior of the package 160 made of the laminated packaging material 200 and to be in direct contact with its contents (e.g., milk, juice or other food). The innermost layer 203 is conventionally a heat-sealable material portion, and when the two surfaces of the innermost layer 203 of the laminated packaging material 200 are placed in direct contact with each other, compressed and heated, they at least partially melt and adhere to each other, thereby forming a strong adhesive seal. This is the process of forming a reference Figure 1 The innermost layer 203 may be a heat sealable polymer, preferably a thermoplastic polymer, selected from polyolefins (such as polyethylene) and polyesters. The innermost layer 203 may be selected from the group consisting of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyethylene furanoate (PEF) and any blend or copolymer of one or more thereof. The innermost layer 203 also has liquid barrier properties to provide a liquid-tight layer toward the filled liquid food. Figure 2a The packaging material 200 in the embodiment further comprises a locally applied portion 204 of a heat-sealable material arranged on top of one or more portions of the innermost layer 203. The locally applied heat-sealable portion 204 also comprises a heat-sealable thermoplastic polymer selected from polyolefins, such as polyethylene or polypropylene, and selected from polyesters, such as polyethylene terephthalate (PET) or polyethylene furanoate (PEF). In one embodiment, the innermost layer and the locally applied heat-sealable material comprise polyethylene, such as low-density polyethylene LDPE, high-density polyethylene HDPE, linear low-density polyethylene LLDPE or single-site catalyzed linear low-density polyethylene m-LLDPE, or a mixture or copolymer thereof.

[0066] Figure 2b Another embodiment of a cross-section of a laminated packaging material 200' is shown. Figure 2a The laminated packaging material 200, Figure 2bThe packaging material 200' in the embodiment includes a body layer 201', an outermost layer 202', an innermost layer 203' and a heat sealable material portion 204'. In addition, the packaging material 200' may further include a barrier layer 205', such as an aluminum foil or a thin metallized aluminum layer, laminated between the innermost layer 203' and the body layer or core layer 201'. Figure 2a and 2b The cross section is taken perpendicularly to the longitudinal extension of the transverse seal TS and / or the sealing element 204, 204'. This will be further explained below with reference to FIG.

[0067] Figure 2a and 2b The laminated packaging material 200, 200' shown in provides a layer that acts as a liquid-tight and gaseous barrier. The laminated packaging material 200, 200' may include additional plastic layers or other barriers (not shown) on both sides of the body layer 201, 201'.

[0068] It should be noted that the dimensions of the heat sealable material portions 204, 204' are exaggerated for illustrative purposes. The width of the heat sealable material portions 204, 204' should be selected to provide adequate sealing in the longitudinal direction of the package 160, while the length of the heat sealable material portions 204, 204' should be selected to extend along the entire seal of the package 160. The thickness of the heat sealable material portions 204, 204' should be selected to obtain adequate bonding, and can be 5 to 50 μm, such as 5 to 30 μm, such as 5 to 20 μm.

[0069] Figure 3a The laminated packaging material 300 is shown to be folded, formed and sealed into a package 160. The inner surface of the innermost layer 303 of the packaging material 300 is shown. Certain transverse seal areas TSA of the innermost layer 303 of the packaging material 300 will be part of the transverse seal TS formed when the packaging container 160 is produced. These areas TSA are Figure 3a The dotted area TSA is along Figure 3a The heat sealable material portion 304 extends in the transverse direction (TD) indicated by the arrow in the figure and is applied to the transverse seal area TSA of the packaging material 300. The packaging material 300 is provided with crease lines which indicate where to fold the packaging material 300 to form the package 160, such as Figure 3b shown. Figure 3b A flat top package 160 made from the disclosed laminated packaging material 200, 200' is shown. The package 160 comprises a longitudinal seal LS and two transverse seals TS (only the upper transverse seal TS is shown). It has an outermost surface 302, a corner 306 and a bottom side edge 307. Although Figure 3bThe package shown in is a flat top package, but it will be appreciated that the packaging material 200, 200' of the present invention is suitable for any type of packaging with a transverse seal TS. When providing a packaging material with a thinner liquid barrier layer before forming the package 160, it must be ensured that a sufficient liquid barrier effect is obtained on all the different parts of the package 160. The thickness of the innermost layer 203, 203' forming the transverse seal TS needs to be thick enough to provide the desired seal. However, applying a continuous thick innermost layer of a heat sealable plastic thermoplastic polymer 203, 203' is expensive and has in fact been shown to involve more such thermoplastic polymer than is actually required for the heat seal performance and integrity of the resulting package.

[0070] The inventors have therefore surprisingly found that reducing the overall thickness of the innermost layer 203, 303' while providing a laminated packaging material 200, 200' having locally applied heat-sealable material portions 204, 204' at certain areas of the innermost layer 203, 203' of the packaging material (e.g. Figure 2a and 2b ) is enough and saves resources, i.e. saves the total raw material thermoplastic polymer amount. Heat sealable material portion 204, 204 'will become a part of the seal (e.g. transverse seal TS) of the formed package, and a sufficient amount of thermoplastic polymer material will be provided to obtain a firm seal. In this way, less material for the innermost layer 203, 203 ' can be used to form a thinner innermost layer 203, 203 ', thereby forming a more environmentally friendly sustainable packaging. In addition, since the material used by the innermost layer 203, 203 ' is less, production costs can be reduced. The additional local application amount of thermoplastic polymer can be applied to the area where the packaging may need further protection and mechanical properties, such as being applied to the corner folding area and the area where the laminated packaging material will be folded to each other at multiple folds (e.g., under the bottom wing and TS folding).

[0071] Since the heat sealable material portions 204, 204' are applied non-uniformly on the laminated packaging material 200, 200', they can be preferably provided to the packaging material 200, 200' after the packaging material 110, 300 has been produced. The process of forming the laminated packaging material 100, 200, 200' without the heat sealable material portions 204, 204' is carried out by a well-known manufacturing process involving a laminating operation, also known as conversion. The body layer 201, 201', the innermost layer 203, 203' and the outermost layer 202, 202' and the optional barrier layer 205', such as an aluminum foil or a metallized film, or other layers providing an oxygen barrier, and additional laminating layers are laminated together during the conversion process. The thickness of the innermost layer 203, 203' may be in the range of 1 to 50 μm, such as 2-50 μm, preferably 2-40 μm, 2-30 μm, 3-30 μm, 3-20 μm, 5-20 μm, 3-15 μm, 5-15 μm.

[0072] Figures 4a to 4c An exemplary formation of heat sealable material portions 204, 204', 404 using injection molding is shown in . To form the heat sealable material portions 204, 204', 404 on the innermost layer 203, 203', 403 of the laminated packaging material 110, 300, an injection molding unit 40 is used before forming the package 160.

[0073] Figures 4a to 4c A first example of how a heat sealable material portion 404 can be formed by an injection molding process is shown in FIG. The laminated packaging material 400 in this example comprises a body layer 401, an outermost layer 402 and an innermost layer 403. In a first stage, as Figure 4a As shown, molten plastic material 410 , such as polyethylene, is transferred into a cavity 412 formed between a first die 414 and a second die 416 .

[0074] In the second stage of this example, Figure 4b As shown, the molten plastic material 410 has heated the innermost layer 403, causing it to at least partially melt, as shown by the dotted areas representing solid material having been replaced by dashed areas representing molten material.

[0075] In the third stage of this example, Figure 4c As shown, the plastic material 410 and the innermost layer 403 have both solidified, and the first mold 414 and the second mold 416 have been removed. At this stage, the heat sealable material portion 404 has been formed. Since the innermost layer 403 is at least partially melted during the injection molding of the heat sealable material portion 404, the heat sealable material portion 404 and the innermost layer 403 are bonded together.

[0076] Figure 4cThe heat sealable material portion 404 is shown to have a rectangular cross-section. However, in some embodiments, it may be preferred to arrange the heat sealable material portion 404 to have a width that increases toward the base and substrate (i.e., toward the innermost layer), i.e., to have a triangular cross-section, or to have a cross-section in the shape of a truncated triangle, such as Figure 5a to Figure 5c This is preferred because a continuously increasing pressure is obtained when the heat-fusible portion material 404 comes together to form a seal. This in turn prevents the polymer from flowing outside the transverse seal area TSA.

[0077] Furthermore, using the geometry of the heat-sealable material portion 404 having a width that increases toward the innermost layer 403, a larger interface area is achieved between the heat-sealable material portion 404 and the innermost layer 403. By providing a triangular cross-section, or a cross-section having a truncated triangular shape, in the transverse direction TD perpendicular to the heat-sealable material portion 404, more heat energy is applied at the interface, thereby improving the bonding of the heat-sealable material portion 404 to the innermost layer 403. This Figure 5a to Figure 5c shown.

[0078] exist Figure 5a to Figure 5c In the embodiment, the laminated packaging material 500 comprises a body layer 501, an outermost layer 502 and an innermost layer 503. In the first stage, as Figure 5a As shown, molten plastic material 510 , such as PE, is transferred into a cavity 512 formed between a mold 514 and the innermost layer 503 .

[0079] In the second stage, if Figure 5b As shown, the molten plastic material 510 has heated the innermost layer 503 and at least partially melted it. Figure 4b The same method is used to illustrate using short lines and dotted areas.

[0080] exist Figure 5c In the third stage shown, the plastic material 510 and the innermost layer 503 have both solidified and the mould 514 has been removed. The heat sealable material portion 504 has been formed.

[0081] It should be noted that Figures 4a to 4c and Figure 5a to Figure 5c The heat sealable material portions 404, 504 are not drawn to scale.

[0082] In order to promote a successful bond between the innermost layer 203, 403, 503 and the heat sealable material portion 204, 404, 504, the interface between the innermost layer 203, 403, 503 and the heat sealable material portion 204, 404, 504 should have the desired temperature for as long as possible. The triangular shape of the cross section or the cross section having a truncated triangular shape prevents the heat sealable material portion 204, 404, 504 from flowing out of the transverse seal area TSA due to the increased pressure generated by joining the heat sealable material portion 204, 404, 504 to form a seal. The cross section also creates a larger surface area in the interface between the two surfaces than a rectangular cross section if the same volume of material forming the sealing element 204, 404, 504 is used.

[0083] Figure 6 A block diagram of a method 600 for forming a laminated packaging material 200, 200', 400, 500 including one or more heat sealable material portions 204, 204', 404, 504 is shown according to one embodiment. The method includes providing a laminated packaging material 100, 300 (e.g. Figure 1 The laminated packaging material 100, 300 may be produced in a conversion process, for example using a conversion process as disclosed in, for example, EP3409462A1 or WO2018220134A1 of the same applicant.

[0084] The packaging material 100, 300 produced in the conversion process is provided unwound from its roll 110 and placed 620 in a heat sealable material portion forming station 40, 50 for forming heat sealable material portions 204, 404, 504. The station 40, 50 is placed inside the filling machine or just before the inlet of the filling machine. The station 40, 50 can be such as Figures 4a to 4c and Figure 5a to Figure 5c An injection molding station as shown, or a spraying station, an inkjet polymer printing station, a sintering station, a welding station or a 3D printing station.

[0085] Optionally, the laminated packaging material 100, 300 is placed 630 in contact with at least one mold 414, 416, 514. The mold 414, 416, 514 can have various shapes, forming heat-sealable material portions 204, 204', 404, 504 of different geometries. The mold 414, 416, 514 can, for example, have a cross section perpendicular to the extension of the sealing element 204, 204', 404, 504 that is triangular, rectangular, hemispherical, or has the shape of a truncated triangle. Preferably, the cross section has a width that increases towards the innermost layer, such as Figure 5a to Figure 5b shown.

[0086] Subsequently, the heat sealable material portion 204, 204', 404, 504 is formed 640 by applying the heat sealable material 410, 510 to the innermost layer 203, 203', 403, 503 of the laminated packaging material 110, 300. Optionally, the heat sealable material 410, 510 is applied by injecting the material into the cavity 412, 512 of the mold 414, 416, 514, as shown in FIG. Figures 4a to 4c and Figure 5a to Figure 5c As shown. The heat sealable material 410, 510 can be a liquid or solid material. For example, it can be a molten material used during injection molding, spraying, coating, or during an inkjet process, or it can be a powder applied to the innermost layer 203, 203', 403, 503 and sintered to attach to the innermost layer 203, 203', 403, 503.

[0087] Injection molding is a mature technology, especially for some proposed materials: PE, PP and PET. When using high-pressure microinjection molding, a small device is made only from these materials on a forward moving packaging laminate in a filling and packaging machine, a first half mold with a first cavity is arranged on a first side of the fiber-based packaging laminate, and a second half mold with a second cavity is arranged on the opposite side of the fiber-based packaging laminate. Typically, the first mold cavity partially overlaps the second mold cavity in one or more overlapping areas. A small amount of polymer melt is then injected into at least the first cavity. Due to the pressure established in the first cavity, the melt will penetrate the fiber-based packaging laminate in the overlapping area and also fill the second cavity to produce an open device extending through the packaging laminate.

[0088] The small amount of plastic used in this technology ensures that even if only the surface layer begins to solidify, this will be enough to maintain the shape of the device until it is fully solidified, which in turn means that once the injection is completed, the mold will be essentially open. The outermost skin of the plastic melt will solidify as soon as it contacts the wall of the mold cavity or the outermost layer of the packaging material. For uncomplicated designs, this ensures that the mold can be opened as soon as it is filled.

[0089] By connecting the two parts (one on each side of the packaging material), i.e., by a molded so-called "bridge", an opening device can be created that can exert forces on both sides of the material in an interactive manner during opening to facilitate opening, while still using very little polymer material for the molded parts of the opening device. In addition, high-pressure microinjection molding technology ensures that the molding process in high-speed filling machines is very efficient in the same operation as packaging forming, filling and sealing.

[0090] The heat sealable material 410, 510 is applied to the package formed from the finished laminated packaging material 200, 200', 400, 500 along what will become the transverse seal TS.

[0091] After the heat sealable material 410, 510 is applied, the material 410, 510 is in direct contact with the innermost layer 203, 403, 503 of the laminated packaging material 100. The large surface area at the interface between the innermost layer 203, 403, 503 and the heat sealable material 410, 510 facilitates the formation of a seal between the heat sealable material portion 410, 510 and the surface of the innermost layer 203, 403, 503.

[0092] Finally, when the heat sealable material 410, 510 is cured, the heat sealable material portion 204, 204', 404, 504 is bonded to the innermost layer. The packaging material 200, 200', 300, 400, 500 can then proceed to a filling station and be formed into a packaging container 160, such as Figure 3b A packaging container 160 is shown.

[0093] The method 600 for producing the laminated packaging material 200,200',300,400,500 of the heat sealable material part 204,204',304,404,504 of local distribution is carried out after the conversion process.Or, method 600 is carried out inside the filling machine or directly carried out before the packaging material 100 enters the filling machine after being unfolded from the reel 110.Therefore, the feeding of laminated packaging material 200,200',300,400,500 should be slow enough to allow the heat sealable material part 204,204',304,404,504 of attachment to solidify.The speed of packaging material can be for example in the scope of 0.5m / s.Although speed is lower than when running through the conversion station with packaging material, slower speed allows to use several different application methods that heat sealable material 410,510 is applied to the innermost layer 203,203',303,403,503.

[0094] The application of heat sealable material parts 204,204',304,404,504 during the lamination / manufacturing process of conversion will not be equally satisfactory, because the laminated packaging material 200,200',300,400,500 comprising the heat sealable material parts 204,204',304,404,504 of local distribution will no longer be uniformly flat.Therefore, the laminated packaging material 200,200',300,400,500 can not be rolled into material reel 110 without damage and problems.The heat sealable material parts 204,204',304,404,504 added will "pile up" when coiling and may provide uneven reel 110.

[0095] Furthermore, as mentioned above, the operating speeds in the conversion are usually much higher than those in the filling machine, which makes it difficult to apply the heat sealable material portions 204, 204', 304, 404, 504. Therefore, local application of additional heat sealable material portions 204, 204', 304, 404, 504 during conversion is less preferred.

[0096] Figures 7a to 7f Shows Figure 4c and Figure 5c A further alternative to a cross section of is that taken in a direction perpendicular to the longitudinal extension of the transverse seal TS and / or the sealing elements 704a - f.

[0097] exist Figure 7a In the embodiment of the invention, the cross section is triangular, which is an advantage of the ultrasonic heat sealing method. As mentioned above, the cross section can alternatively be a truncated triangular shape, thereby providing the same effect. The apex or narrower top of the applied profile of the additional material portion will ensure that heat generation occurs in a more concentrated manner. Alternatively, the apex or top can be rounded, i.e. the cross section is approximately triangular.

[0098] Figure 7b A similar but asymmetrical cross section is shown, for the same purpose, having the body of added material displaced transversely within the cross section of the applied portion of the heat sealable material. This profile may be used along the full extension of the transverse heat seal or along a portion thereof where it is desired to reduce the amount of added material. For heat sealing large packages of liquid contents, it may be necessary to add a higher amount of polymer material, but still avoid any such excess material from flowing out of the sealing fin area and interfering with the cutting action, as described below with respect to Fig.10 As explained.

[0099] Figure 7c An embodiment is shown in which the cross section is asymmetrical but is capable of accommodating a higher amount of heat sealable material, which may be more suitable for larger packaging containers for liquid products than for conventional packaging containers. Figure 7b The situation is more favorable.

[0100] exist Figure 7d , 7e and 7f show the Figure 7a , 7b Embodiments with a cross section similar to 5c but with a hollow interior. These embodiments may be suitable for heat sealing of smaller packages (e.g., portioned packages of up to 300 ml of liquid beverages or food) where a lower strength heat seal is applicable, or when a wider base toward the innermost layer of the seal is required. With these embodiments, a wide transverse seal with a reduced amount of heat-sealable material but at the same time concentrating the generation of heat for an optimal sealing process will be possible.

[0101] Fig. 8a shows a cross section of a prior art folded tube (the folded transverse edge area is not shown) made of a conventional laminated packaging material 80 having an innermost heat-sealable layer 81 during transverse sealing, so that the innermost heat-sealable layer 81 is sealed to itself on the opposite wall of the tube. In order to cover the opening edge 83 of the laminated packaging material on the inside of the tube, a longitudinal strip 82 of heat-sealable material is applied on the inner longitudinal edge 83. The longitudinal strip 82 is sealed on the inner longitudinal edge 83 of the opening and further sealed to the inside of the outer edge 84 of the packaging material 80, so that the longitudinal overlapping seal area will be tightly sealed and prevented from contacting the filled liquid product on the inside of the tube by the longitudinal strip 82.

[0102] Figure 8b to Figure 8c A variant of the cross section of a folded tube to be transversely sealed is shown which, instead of having only a very thin layer of heat-sealable material on the inside of the laminated packaging material, additionally has a locally applied heat-sealable material portion which is at least partially applied along the extension of the transverse seal area. In order to cover the open edge 83 of the laminated packaging material on the inside of the tube, a longitudinal strip 82 of heat-sealable material is still applied to the inside longitudinal edge 83 as described above, but for reasons of visibility in these figures, the longitudinal strip 82 is not shown.

[0103] therefore, Figure 8bShown the cross section of folded tube (its folded transverse edge region is not shown), this folded tube is made by the laminated packaging material 80b with very thin innermost heat sealable layer 81b in the process of transverse sealing, so that the inner surface with innermost heat sealable layer 81b can be sealed to itself on the relative wall of tube.The application thickness of innermost layer 81b is only enough to protect the inner layer of packaging laminate, such as paperboard body layer or core layer and film or foil with barrier layer or coating, from moisture and dirt, but is not enough to provide firm and durable heat seal for liquid carton packaging.Except the innermost layer 81b previously applied, the locally applied heat sealable material part 85 is applied along the extension in the transverse seal area, as local thickness from the angle in the figure.The locally applied heat sealable material part 85 is applied as material strand along the whole extension in the transverse seal area.From this angle, the strand applied will only be shown as additional thicker layer, and has nothing to do with cross-sectional profile. In addition, additional amounts 87b and 88b of heat-sealable material are applied near the longitudinal edges 83 and 84 of the packaging material web to form a strong and durable overlapping seal 86b also along the longitudinal seam of the packaging material tube. Due to the double layer of material at the overlapping seam, when the rods of the transverse sealing jaws squeeze the tube walls against each other to form a flat transverse seal, a higher pressure will act on the area of ​​the longitudinal seal LS. To ensure that there is enough heat-sealable material in the LS overlapping area, as shown in the figure, an additional amount is applied at the edge area. Additional material 85b is applied along the entire extension of the transverse seal to correspond to the thicker innermost layer at least in the seal area.

[0104] Figure 8c Shown the alternative cross section of folded tube (its folded transverse edge region is not shown), this folded tube is made by the laminated packaging material 80c with very thin innermost heat sealable layer 81c in the process of transverse sealing, so that the inner surface with innermost heat sealable layer 81c can be sealed to itself on the relative wall of tube.The application thickness of innermost layer 81c is only enough to protect the inner layer of packaging laminate, such as paperboard body layer or core layer and film or foil with barrier layer or coating, from moisture and dirt, but is not enough to provide strong and durable heat seal for liquid carton packaging.Except the innermost layer 81c previously applied, the heat sealable material part 85c of local application is applied along some parts of the extension in the transverse seal area, as local thickness from the angle in the figure.Therefore, the heat sealable material part 85c of local application is applied as material strand along the extension in the transverse seal area.From this angle, the strand applied will only be shown as additional thicker layer, and has nothing to do with cross-sectional profile. Furthermore, as described above, additional quantities 87c and 88c of heat sealable material are applied adjacent the longitudinal edges 83c and 84c of the packaging material web for the same purpose to form a strong and durable overlapping seal 86c also along the longitudinal seam of the packaging material tube.

[0105] Fig. 9 Shown is a transverse sealing area 140 as seen from above on the inside of the flat packaging material roll, which includes an upper end seal 5a (whose future position is indicated by a bold line) and a lower end seal 5b (whose future position is indicated by a bold line). The area of ​​the packaging material 132a above the upper end seal 5a corresponds to a packaging unit and has a set of crease lines applied thereto, which will enable the packaging to be folded into shape later. The end seal 5a will usually become the top seal of the formed packaging, so we also call it the "upper" end seal. However, it can alternatively become the bottom seal of the formed packaging, depending on how the filling machine is configured. The area of ​​the packaging material 136a below the lower end seal 5b therefore corresponds to another packaging unit and has a set of crease lines applied thereto, which will enable the other packaging to be folded into shape later. The end seal 5b will usually become the bottom seal of the formed packaging, so we call it the "lower" end seal here.

[0106] The post-forming cut region 5c of the tube extends between the upper end seal 5a and the lower end seal 5b.

[0107] Therefore, the transverse sealing area 140 includes a lower sealing area 142, which is used to form a lower seal of the lower package when positioned in the tube during filling; an upper sealing area 144, which is used to form an upper seal of the upper package when positioned in the tube during filling; and a cutting area 146 arranged between the lower sealing area 142 and the upper sealing area 144.

[0108] The packages are cut from the tube of packaging material along the centre line of the transverse cut area 146, i.e. along the transverse linear cut 148. When the packages are cut from the tube, they will therefore have narrow fins of packaging material extending below the upper transverse seal 5a and above the lower transverse seal 5b, respectively.

[0109] Additional heat-sealable material is applied locally along the extension of the lower end seal 5a and the upper end seal 5b.

[0110] Usually, a larger amount of heat sealable material can be arranged in a transverse position corresponding to the position of the longitudinal seal of tube 150a, 150b along the extension of the end seal area 5a, 5b, wherein the longitudinal edges of the coil-shaped packaging material will overlap each other. When the rod of the transverse sealing jaws squeezes the tube wall to form a flat transverse seal, due to the double-layer material at the overlapping seam 86, a higher pressure will be arranged on the area of ​​the longitudinal seal LS. In order to ensure that some heat sealable material stays in the overlap, an additional amount is applied to this area. The additional amount is shown as a higher part at the position just beside the overlapping seam on the part applied locally, or a wider part from the figure above.

[0111] A larger amount of heat-sealable material may also be arranged along the extension of the end seal regions 5a, 5b at transverse positions corresponding to the positions where the tube will be folded during sealing, i.e. at positions corresponding to the transverse edges of the tube. It has been demonstrated that the additional amount of thermoplastic polymer material improves the seal strength of the tube at these positions 150c, 150d, and therefore also improves the integrity and appearance of the final package.

[0112] Similar larger amounts of heat sealable material may also be applied at other locations along the extension of the end seal regions 5a, 5b to ensure a proper and durable transverse seal in the package formed in the tube filling and sealing operation.

[0113] Fig.10 An isometric view is shown of an extension of a locally applied portion of heat-sealable material 10 at the upper transverse seal 5a (the transverse seal that will become the upper seal of the first package formed by the packaging unit 11). A linear region 12 that will become the transverse linear cut 148 is shown next to the dotted line. On the other side of the linear region 12, there is a corresponding locally applied portion of heat-sealable material (not shown) at the lower transverse seal 5b (i.e., the transverse seal region that will include the lower seal of the package formed by the adjacent packaging unit below the first package). Fig.10As shown, the locally applied portion of heat sealable material 10 has an asymmetric cross section, so as to avoid the additional material locally applied when sealing will float too far and enter the upper sealing fin 13 below the upper seal 5a. If too much heat sealable material floats in this direction during sealing, it may reach the cutting knife in operation and cause problems, and the heat sealable material of for example melting may solidify during cutting operation, thereby causing the packaging cut off to still adhere to each other, causing the additional wear of sharp cutter and the emission of cutter and the blocking of retraction mechanism. In this particular embodiment shown, the cross section of the locally applied heat sealable material part is triangular, therefore has the inclined surface towards the cutting line. In addition, as mentioned above, the heat sealable material of higher amount can be added at some positions of the extension of the end seal (for example at the folding edge of the tube in the region forming the longitudinal overlapping seal and in the transverse seal region).

[0114] From the above it can be seen that, although various embodiments of the invention have been described and shown, the invention is not restricted thereto but can also be embodied in other ways within the scope of the subject matter defined in the appended claims.

Claims

1. A packaging material, comprising a core layer (201, 201', 401, 501); an outermost layer (202, 202', 402, 502) arranged to face the outside of a packaging container made of the packaging material (200, 200', 400, 500); and an innermost layer (203, 203', 403, 503) arranged to face the inside of the packaging container, the outermost layer (202, 202', 402, 502) and the innermost layer (203, 203', 403, 503) being laminated to the core layer (201, 201', 401, 501), It is characterized in that The laminated packaging material (200, 200', 400, 500) further comprises a locally applied heat-sealable material portion (204, 204', 404, 504) arranged on the innermost layer (203, 203', 403, 503), wherein the heat-sealable material portion (204, 204', 404, 504) is arranged at a sealing area corresponding to the position of a transverse seal of the resulting packaging container, wherein the heat-sealable material portion (204, 204', 404, 504) has a cross-section whose width increases towards the innermost layer (203, 203'403, 503).

2. The packaging material according to claim 1, wherein the heat-sealable material portion (204, 204', 404, 504) is adhered to the innermost layer (203, 203', 403, 503) by a heat application process, and the heat application process is an injection molding process, a sintering process, a welding process, a spraying process, an inkjet polymer printing process, a compression molding process or a 3D printing process.

3. The packaging material according to claim 1 or 2, wherein the heat-sealable material portion (204, 204', 404, 504) has a thickness of 2-50 μm.

4. The packaging material according to claim 3, wherein the heat-sealable material portion (204, 204', 404, 504) has a thickness of 3-30 μm.

5. The packaging material according to claim 4, wherein the heat-sealable material portion (204, 204', 404, 504) has a thickness of 3-20 μm.

6. The packaging material according to claim 5, wherein the heat-sealable material portion (204, 204', 404, 504) has a thickness of 5-20 μm.

7. The packaging material according to claim 6, wherein the heat-sealable material portion (204, 204', 404, 504) has a thickness of 5-15 μm.

8. The packaging material according to claim 1 or 2, wherein the heat-sealable material portion has a cross-section in the shape of a triangle or a truncated triangle.

9. The packaging material according to claim 1 or 2, wherein the heat-sealable material portion has an asymmetrically shaped cross-section.

10. Packaging material according to claim 1, wherein the heat-sealable material portion (204, 204', 404, 504) is arranged along the entire extension of the transverse sealing area.

11. A packaging material according to claim 10, wherein the heat sealable material portion is arranged to have a varying cross section along the extension of the transverse seal area.

12. A packaging material according to claim 11, wherein the heat sealable material portion has a cross-section providing a higher amount of polymer material at a predetermined position along the extension of the transverse seal area.

13. A packaging material according to claim 12, wherein a higher amount of heat-sealable material is applied along the extension of the transverse sealing area at locations close to the longitudinal edges of the packaging material.

14. The packaging material according to claim 1 or 2, wherein the seal initiation temperature, ie the softening temperature, of the thermoplastic polymer of the topically applied heat-sealable material portion is lower than the corresponding seal initiation temperature of the thermoplastic polymer of the innermost layer.

15. The packaging material according to claim 14, wherein the seal initiation temperature of the thermoplastic polymer of the topically applied heat-sealable material portion is the Vicat point or the glass transition temperature and / or the melting temperature.

16. The packaging material according to claim 1 or 2, wherein the heat sealable material portion (204, 204', 404, 504) is made of a thermoplastic polymer selected from the group consisting of polyolefins and polyesters.

17. The packaging material according to claim 1 or 2, wherein the packaging material (200, 200', 400, 500) further comprises a barrier layer (205') arranged between the core layer (201, 201', 401, 501) and the innermost layer (203, 203', 403, 503).

18. The packaging material according to claim 1 or 2, wherein the core layer (201, 201', 401, 501) is a cellulose based material.

19. Packaging material according to claim 18, wherein the core layer (201, 201', 401, 501) is paper or paperboard.

20. A method for producing a packaging container from a packaging material (200, 200', 400, 500), the method (600) comprising the following steps: Providing the packaging material by laminating (610) an innermost layer (203, 203', 403, 503) and an outermost layer (202, 202', 402, 502) to a core layer (201, 201', 401, 501); locally applying (650) heat to the innermost layer (203, 203', 403, 503) a portion of heat-sealable material (204, 204', 404, 504), wherein the portion of heat-sealable material (204, 204', 404, 504) is arranged at a sealing area corresponding to the position of a transverse seal of the resulting packaging container, wherein the portion of heat-sealable material (204, 204', 404, 504) has a cross-section with a width increasing towards the innermost layer (203, 203'403, 503), Forming a packaging container from the packaging material (200, 200', 400, 500); filling the packaging container; as well as The packaging container is heat-sealed by the heat-sealable material portion (204, 204', 404, 504) to form a closed packaging container.

21. The method of claim 20, wherein applying heat (650) is performed using an injection molding process, a sintering process, a welding process, a spraying process, a compression molding process, an inkjet polymer printing process, or a 3D printing process.

22. The method according to claim 20 or 21, wherein the innermost layer (203, 203', 403, 503) is selected from heat-sealable polymers.

23. The method of claim 22, wherein the heat sealable polymer is a thermoplastic polymer selected from the group consisting of polyolefins and polyesters.

24. The method of claim 23, wherein the polyolefin is polyethylene.

25. A packaging container made of a packaging material according to any one of claims 1 to 19, the packaging material comprising a core layer (201, 201', 401, 501) and an outermost layer (202, 202', 402, 502) laminated thereto and an innermost layer (203, 203', 403, 503), wherein a heat-sealable material portion (204, 204', 404, 504) is locally arranged on the innermost layer (203, 203', 403, 503).

26. The packaging container according to claim 25, wherein the portion of heat-sealable material is arranged locally at the location of one or more transverse seals of the packaging container.

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