Packaging material sheet, method of folding into package, and package
The packaging material with strategically placed weakening elements addresses the issue of insufficient sealing by redirecting material extrusion, ensuring robust and reliable seals, thus preventing buckling and leakage.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TETRA LAVAL HOLDINGS & FINANCE SA
- Filing Date
- 2024-06-04
- Publication Date
- 2026-06-18
AI Technical Summary
Existing packaging materials face issues with insufficient sealing at the peripheral edges of lateral seals, leading to buckling and potential sealing defects due to the warping of the cellulose layer, which can compromise the integrity of the package.
A packaging material with first and second weakening elements positioned on either side of the peripheral fin edge, redirecting material extrusion away from the edge to form bulges at these elements, thereby ensuring a reliable seal by avoiding material accumulation at the edge.
This design reduces the risk of bulging and enhances sealing reliability, maintaining package integrity and reducing the risk of leakage by minimizing stress and strain on the packaging material.
Smart Images
Figure 2026519779000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to packaging technology. More specifically, it relates to a cellulose-based packaging material sheet, a packaging material web, a package, a method for manufacturing the sheet, and a method for manufacturing the package.
Background Art
[0002] Roll-fed filling machines for manufacturing carton-based packages have been known since the 1940s. A well-known example currently available is Tetra Pak® A3 Speed sold by Tetra Pak®. The general principle of such a machine is to form a tube from a web of packaging material, fill the tube with food from above, and seal and cut the lower end of the tube to form a package. In addition to high speed, by subjecting the packaging material to sterilization treatment and the food to treatment, the package can protect the food for a long period. For example, a roll-fed filling machine can be used to fill aseptic packages with UHT (ultra-high temperature sterilization) treated milk.
[0003] As an alternative to roll-fed filling machines, blank-fed filling machines can be used. Different from roll-fed packaging machines, blank-fed packaging machines often use pre-manufactured flat-folded sleeves of packaging material, often called blanks. In such a machine, after the blank is taken out from the magazine, it is assembled into a sleeve. At the bottom forming station, the sleeve is folded and sealed to form the bottom. At the filling station downstream of this station, the sleeve with the bottom formed is filled with food. When the food is filled into the package, the top is formed by the top forming station. An example of such a blank-fed filling machine is Tetra Pak® TR / 27 that produces Tetra Rex® packages.
[0004] Fold lines can be provided in packaging materials to ensure uniform and reliable folding. In many cases, the folded portion of the packaging material is deformed between male and female molds, and the cardboard layer of the packaging material is weakened in these areas. One effect of weakening the cardboard layer is that the folding is guided to the portion with the deformed cardboard layer.
[0005] Various technologies have been developed for forming fold lines. For example, International Patent Publication WO2015 / 193358A1 by Tetra Laval Holdings & Finances SA proposes a method for creating fold lines at the corners of a package. International Patent Publication WO2009 / 131496A1 discloses a method for creating internal folds in packaging laminates that can be used to reduce the risk of cracking of the aluminum foil layer when bent. U.S. Patent Registrations 4, 287, 247 present packaging laminates with fold lines that can reduce the risk of cracking and leakage when bent. European Patent Registration 0027668 discloses packaging laminates with fold lines positioned to address the problem of cracks that occur when bent, particularly cracks that occur at the intersection of transverse and longitudinal seals. [Overview of the project] [Problems that the invention aims to solve]
[0006] While current packaging materials can form packaging in a reliable and consistent manner, there is room for improvement. For example, there is a need for packaging materials that can be easily folded while minimizing the risk of insufficient sealing at the peripheral edges of the lateral seals (upper and lower fins). Packaging materials can be folded, for example, by about 180 degrees. This can cause buckling of the cellulose layer (e.g., cardboard), i.e., warping of the cellulose layer. This buckling can lead to the aforementioned sealing defects. [Means for solving the problem]
[0007] The object of the present invention is to overcome at least some of the limitations of the prior art specified above. In particular, it is to reduce the risk of insufficient sealing at the peripheral fin edges.
[0008] According to a first embodiment, a sheet of packaging material is provided which is processed to form a package for containing a food product. The packaging material may comprise an outer protective layer, a cellulose layer, and an inner protective layer that prevents contact between the food product and the cellulose layer, all of which are positioned to face the surrounding environment. The sheet may include a sealing portion formed on the fins of the package. The sealing portion may include an edge region positioned to form the peripheral fin edge of the package. The edge region may be provided with first and second weakening elements positioned on different sides of the peripheral fin edge, each located at a first and second lateral distance, respectively, from the peripheral fin edge.
[0009] The advantage of providing the first and second weakening elements is that when folded, the material extruded towards the peripheral fin edge is extruded in the form of bulges at the first and second weakening elements, respectively, instead of bulging at the peripheral fin edge. By keeping the material away from the peripheral fin edge in this way, a more reliable seal is obtained at the peripheral fin edge. Therefore, since no bulges (including at least a portion of the cellulose layer) are located between the opposing inner protective layers when folded, it is possible to seal while avoiding the formation of unsealed channels between the opposing inner protective layers.
[0010] The package may be formed by folding the packaging material into a parallelepiped shape, or it may be formed without folding into a pouch-type package. An essential feature is that it has a sealing section that can seal the package before and / or after the food is filled.
[0011] Cellulose layers can provide robustness to sheets and packages. These can be paper layers, particularly the cardboard layers known in the liquid food packaging sector.
[0012] The inner and outer protective layers are layers known in the art to protect the cellulose layer from wetting, such as polymer layers, and are extruded or laminated onto one or both sides of the cellulose layer. The number of protective layers may be one or more, depending on the protective performance of the package.
[0013] The packaging material may include additional layers other than the protective layer and the cellulose-based layer.
[0014] The folding region between the first weakening element and the second weakening element can be a region without any weakening elements. In other words, the folding region between the first weakening element and the second weakening element can be formed without any weakening elements at all.
[0015] By not placing weakening elements on the peripheral fin edges, there is an advantage in that the risk of breakage due to the expansion effect of weakening elements on the fin edges can be reduced in the packaging material, especially in the "inner" layer on the cellulose-based layer side that faces the food product when the package is formed and filled.
[0016] Additional weakening elements to be avoided may include weakening in any direction, such as straight folds in the vertical or horizontal direction.
[0017] The bending region can be defined not only between the regions where the first and second weakening elements exist, but also between the protrusions of the first and second weakening elements, particularly the longitudinal protrusions (virtual extensions). In this case, the packaging material will not have the transverse folds present around the first and second weakening elements in some packaging configurations within the bending region.
[0018] The weakening elements described in this application may be at least one of slits, holes, folds, or compression. Compression may be formed by creating a recess on the sheet. The recess may be configured in such a way that it does not create a bulge on the opposite side of the sheet.
[0019] All weakening types may be applied to the cellulosic layer itself, to any step in the lamination process, or to any layer present on the cellulosic layer. In any alternative, it is important that the weakening element ultimately has an effect on the cellulosic layer.
[0020] For example, the first and second weakening elements, which serve as folds, can be formed by female and male molds. This can simplify the processing steps for packaging materials compared to other types of weakening processes in the art. The cross-sectional shape of the mold may be symmetrical, such as a U-shape, or asymmetrical, as described later. The fold may have a recess on one side of the sheet and a protrusion on the other side.
[0021] When the packaging material is folded to form the package, the first and second weakening elements may be connected to or separated from any possible upper and lower flap fold lines. By connecting or spacing, a variety of designs can be realized between the first and second weakening elements and the upper and lower flap fold lines, to the extent that the design is within the scope of the claims and is technically possible for those skilled in the art. At least one sealing portion includes an upper sealing portion and a lower sealing portion, the upper sealing portion may include first and second upper fin edges, and the lower sealing portion may include first and second lower fin edges.
[0022] The packaging material may further include a barrier layer positioned between the cellulose layer and the inner protective layer.
[0023] The barrier layer may be more sensitive to stress and strain than the cellulose layer and / or protective layer. For this reason, when the packaging material includes a barrier layer, it may be particularly important to provide first and second weakening elements.
[0024] A barrier layer may be used to prevent the deterioration of food stored in the package. For example, it may be a barrier layer against oxygen and / or light. There may be one or more layers having the same or different barrier properties.
[0025] As an example, the barrier layer may be a fibrous barrier layer (for example, a paper-based barrier layer). The fibrous barrier layer has a paper substrate layer coated with a coating layer having barrier properties. The paper substrate layer can be coated by an aqueous dispersion coating method using a dispersion or solution of a composition capable of imparting barrier properties against oxygen, water vapor and / or other migratory substances. Examples of such compositions include aqueous compositions containing vinyl alcohol polymers or starch or other polysaccharides, and may further contain fillers such as talc, bentonite and other clay minerals or layered mineral compounds as required. Alternatively, or additionally, the paper substrate layer may be coated by a deposition method such as chemical vapor deposition and / or physical vapor deposition. In a preferred embodiment, it can be a vapor deposition coating with a thickness of a few nanometers of a metal such as aluminum.
[0026] As another possible example, the barrier layer can be a polymer-based barrier layer. The polymer-based barrier layer may be composed of a single polymer layer having inherent gas barrier properties. Alternatively, it may be composed of a layer having a polymer-based layer and coated with a coating layer having barrier properties thereon. The polymer substrate may be a prefabricated film having a single-layer or multi-layer structure, and is further coated by a deposition method such as chemical vapor deposition and / or physical vapor deposition in the same manner as described above for the fiber-based barrier substrate. For example, such a polymer barrier substrate may be vapor-deposited and / or deposited with an inorganic oxide such as a metal oxide. It has also been confirmed that such a polymer-based barrier layer is difficult to perforate or penetrate, and therefore a specific powerful device is required.
[0027] This type of fibrous or polymeric barrier layer is considered particularly beneficial in the recycling cycle of packages formed by the packaging material according to the claims.
[0028] The distance between the first weakened element and the second weakened element can be 1 to 6 mm. This distance may be defined in relation to the thickness of the sheet or the thickness of the cellulosic layer. In one embodiment, for packages with an internal volume of about 50 to 500 ml, it can be about 2 mm, and for packages with an internal volume of about 500 to 2000 ml, it can be about 2.2 mm. The spacing between the weakened elements can be 5 to 20 times the thickness of the cellulosic layer. Thereby, the risk of bulging and thus the problem of poor sealing can be avoided.
[0029] The first and second weakened elements have an outer inclination angle steeper than the inner inclination angle, or an inner inclination angle steeper than the outer inclination angle. The advantage of making the first and second weakened elements asymmetric is that it can reduce the stress and strain on the packaging material, and at the same time, can keep the risk of bulging at the peripheral fin edge low.
[0030] According to a second aspect, a web of packaging material including a plurality of sheets continuous with each other is provided. The sheets are arranged according to the first aspect. Thereby, a continuous roll of packaging material can be efficiently processed or manufactured. Further, sheets arranged below each other can be added to form a multi-row continuous roll packaging material. Thereby, it is possible to further increase the production efficiency. The production of the packaging material can be carried out at a processing speed of the material of 200 m / min or more. Therefore, continuous and mass production of the packaging material can be achieved.
[0031] The packaging material can be transformed into a package in a filling machine that forms a package from a sheet according to a first embodiment. The filling machine may include a lateral sealing station positioned to fold the edge region of the sheet to the peripheral fin edge and then weld the sealing portion to the fin to form a seal on the fin of the package. The filling machine may be a roll-feed filling machine that is supplied with a web-like sheet according to a second embodiment. This enables continuous filling and package formation. The lateral sealing station may use induction heating or ultrasonic heating to melt the inner protective layer of the sheet. This makes it possible to employ different types of laminate layers (e.g., barrier layers) in the packaging material while maintaining airtightness.
[0032] A third embodiment provides a method for manufacturing a sheet of packaging material. This method may include laminating an outer protective layer and an inner protective layer to a cellulose layer and deforming the cellulose layer to form a first weakening element and a second weakening element at the edge of the sheet. Here, the first weakening element and the second weakening element are positioned on different sides of the peripheral fin edge at distances of a first lateral distance and a second lateral distance, respectively, from the peripheral fin edge.
[0033] The same features and advantages presented with respect to the first embodiment described above also apply to this embodiment.
[0034] A fourth embodiment provides a method for manufacturing a package from a sheet of packaging material. The edge region of the sheet may be provided with first and second weakening elements positioned on different sides of the peripheral fin edge at first and second lateral distances, respectively, from the peripheral fin edge. The method may comprise supplying the sheet, folding and sealing the sheet to form fins, wherein the first and second weakening elements are such that the bulge of the packaging material is guided from the peripheral fin edge toward the first and second weakening elements, respectively.
[0035] The same features and advantages presented with respect to the first embodiment described above also apply to this embodiment.
[0036] According to the fifth aspect, a package obtained by the method according to the fourth aspect is provided.
[0037] Further objects, features, embodiments, and advantages of the present invention will become apparent from the following detailed description and drawings.
[0038] In the manufacture of packaging materials, all terms such as transverse and longitudinal refer to the direction in which the wound cellulose layer and / or sheet flows, which defines the longitudinal direction, and the direction perpendicular to the longitudinal direction, which defines the transverse direction. Terms such as top and bottom refer to the package formed from the packaging material, where the top of the package is the part that is in contact with the surface when the package is standing upright, and the bottom is the part that is in contact with the surface. Alternatively, the part of the package in which food is filled is the top, and the sealed part on the opposite side of the package is the bottom. In either case, the directional or relative terms used are well known to those skilled in the art of food packaging. [Brief explanation of the drawing]
[0039] Embodiments of the present invention will be described illustratively with reference to the attached schematic diagrams.
[0040] [Figure 1] This is a perspective view of a roll-feed filling machine. [Figure 2] This figure shows a web sheet of a packaging material not illustrating the present invention. [Figure 3] Figure 2 is a perspective view of the package formed from the sheet shown. [Figure 4] This diagram shows a typical example of a bulge that occurs when folding a sheet using conventional technology. [Figure 5] This is a cross-sectional view of the fin edge around the package, where the bulge is formed by folding the sheet using conventional technology. [Figure 6] This diagram schematically illustrates how the first and second weakening elements mitigate the formation of bulges at the folds. [Figure 7]This is a cross-sectional view of the peripheral fin edge where the first and second weakening elements are provided and the first and second offset edge bulges are formed. [Figure 8] This figure shows a fold line pattern suitable for the package type of Figure 2, which has the first and second weakening elements. [Figure 9] This is a cross-sectional view of a tool that can be used to provide the first and second weakening elements. [Figure 10] This is a flowchart showing a method for manufacturing packaging material sheets. [Figure 11] This is a flowchart showing the process of manufacturing a package from a packaging material sheet. [Modes for carrying out the invention]
[0041] Figure 1 shows the general principle of a roll-feed filling machine 100. The packaging material 102 is supplied in the form of a web wound on a reel. After the web is unwound from the reel, it can be sterilized (not shown) for example using a hydrogen peroxide bath or a low-voltage electron beam (LVEB) station. In addition to sterilization, i.e., removing unwanted microorganisms from the packaging material 102, it is possible to form an opening device into the packaging material 102. This is sometimes called a pre-attached or pre-installed opening device (also not shown). The web can be formed into a tube 104 by forming a longitudinal seal 106. This seal is provided by guiding the web so that the first longitudinal edge 108 of the web overlaps with the second longitudinal edge 110, generating heat that at least partially melts the outer and inner protective layers of the packaging material 102, and applying pressure to create adhesion between the two edges 108, 110. As shown, the formation of the longitudinal seal 106 is performed continuously. Although not shown in the diagram, it is possible to attach a so-called LS strip (longitudinal sealing strip) to the inside of the tube 104 to prevent contact between the food product FP inside the tube 104 and the cellulose layer of the packaging material 102.
[0042] Food product FP is supplied from above through food pipe 112 to tube 104. A lateral seal 114 can be formed at the lower end of tube 104. The tube 104 can be cut simultaneously with the formation of the lateral seal 114. In this way, the upper fin of the first package and the lower fin of the second package following the first package can be provided simultaneously. Lateral sealing and cutting can be performed at a lateral sealing station 118 (descriptively shown here as a box). Induction heating can be used for heating during sealing. Another option is to generate heat using ultrasound. Downstream of the lateral sealing station 118, the package 116 can be folded into its final shape. For example, a final folding device can be used to form panels or flaps and produce a brick-shaped package.
[0043] Instead of manufacturing the package with the top facing upwards and the bottom facing downwards, it is also possible to manufacture it in the opposite direction, that is, with the top facing downwards and the bottom facing upwards.
[0044] Although a roll-feed filling machine 100 is illustrated, other methods exist for manufacturing the package 116. For example, it is possible to use a so-called blank-feed machine. In these machines, the longitudinal seal 106 and cuts are almost always pre-formed and not formed within the filling machine. Thus, the packaging material is supplied in the form of a blank, i.e., a flat-folded sleeve of packaging material. Unlike the roll-feed filling machine 100, the top and bottom of the package are formed at different stations.
[0045] Figure 2 shows the packaging material 102 in more detail. As shown, the packaging material web 102 can be divided into sheets 200, and one package 116 is produced from one sheet 200. When a blank-feed filling machine is used instead of a roll-feed filling machine 100, the sheets 200 are sealed longitudinally and folded flat.
[0046] By providing a fold line 202, the process of folding the sheet 200 into the package 116 can be facilitated. The packaging material 200 may be a carton-based packaging material, more specifically, a laminate having a polymer-based layer as an outer protective layer, which prevents moisture from penetrating into the carton-based layer inside this outer layer. The carton-based layer, more generally a cellulose-based layer, serves the purpose of providing robustness as well as reducing the environmental impact of the package 116. Since the cardboard may degrade over time when in contact with liquids such as food product FP, an inner protective layer may be provided to prevent the food product FP held in the package 116 from directly contacting the carton-based layer. Often, multiple layers may be used rather than just a single inner protective layer, and similarly, multiple outer protective layers may be used. A barrier layer may be added to block light from reaching the food product FP held in the package 116. When using the carton-based packaging material 200 described above, the fold line 202 is provided by deforming the cardboard along the fold line 202. By deforming the cardboard, the fibers are damaged, weakening these areas and making it easier to fold.
[0047] The sheet 200 shown in Figure 2 is an example of a sheet that is formed into a block-shaped package 116. The upper flap fold line 202a is provided to facilitate the formation of the upper flap, which is folded down and adhered to the side panel of the package 116. Furthermore, a vertical main fold line 202b can be provided to facilitate the formation of the front panel, side panel, and back panel. A bottom flap fold line 202c can be provided for the formation of the bottom flap. Cutting lines 204 can be provided between the edges 206a to d of the continuous sheet 200.
[0048] As shown in the figure, an upper sealing portion 208 can be provided on the upper part of sheet 200, and a lower sealing portion 210 of the subsequent sheet can be provided on the opposite side of the cutting line 204, next to the upper sealing portion 208. Below the upper sealing portion 208, an upper section 212 can be provided. Further down, a main section 214 can be provided. Further down, a lower section 216 can be provided. Next to the lower section 216, a lower sealing portion 210 can be provided.
[0049] Figure 3 shows an example of a package 116 that can be formed from the sheet 200 shown in Figure 2. Specifically, the upper section 212 can form the upper part 300, the main section 214 can form the body 302, and the lower section 216 can form the bottom part 304. A longitudinal seal 306 can be provided between the two back panels of the package 116. Although not shown, another option is to place the longitudinal seal at the corner between either the back panel or the side panel. The fins 312 are formed by providing a transverse seal 308 having two peripheral fin edges 310. Although not shown, a lower fin may be provided in addition to the illustrated fins 312 (i.e., upper fins). However, instead of a flap that folds down onto the side panel, the flap of the lower fin may be folded inward.
[0050] When the packaging material 102 is folded to form the peripheral fin edge 310, a problem may occur in which a bulge 400 forms inside the packaging material 102, as shown in Figure 4. When both sides of the packaging material 102 are folded toward each other (as indicated by the arrows), the material of the packaging material 102 moves toward the fold line, i.e., the peripheral fin edge 310 (similarly indicated by the arrows). As the material is pushed toward the center of the fold, it is extruded in the form of a bulge 400. If there is no fold line as shown in the figure, a bulge 400 may occur. If a fold line is provided to facilitate folding, the risk of a bulge 400 forming may be further increased. Specifically, the fold line has the effect of reducing the strength of the peripheral fin edge 310 portion of the packaging material 102, thereby increasing the risk of the material being extruded as a bulge 400. If a bulge 400 occurs, it will adversely affect the lateral seal portion 308, and as a result the integrity of the package may be insufficient.
[0051] Figure 5 shows an example of a peripheral fin edge 310 where a bulge 400 is formed. In this particular example, the packaging material comprises an outer protective layer 500, a cellulose substrate layer 502 (more specifically, a carton base layer), and an inner protective layer 504. As shown in the figure, the cellulose substrate layer 502 may cause the bulge 400. One reason for this is that the cellulose substrate layer 502 is constructed differently from the outer and inner protective layers 500, 504. In this particular example, the outer and inner protective layers are polymer-based.
[0052] As shown in Figure 6, by positioning the first and second weakening elements 604 and 606 on both sides of the peripheral fin edge 310, i.e., the center of the fold, the material pushed toward the center of the fold reaches the area of the deformed packaging material 102, i.e., the area where the fibers are damaged. Due to the weakening effect on the packaging material 102, the material pushed toward the center of the fold is redirected toward the inside of the lateral seal portion 308, resulting in the formation of the first and second offset edge bulges 600 and 602. Therefore, by providing the first and second weakening elements 604 and 606, the amount of material pushed toward the peripheral fin edge 310 is reduced. A desirable effect of this is that the stress and shear force at the peripheral fin edge 310 are reduced, and the risk of damage to the packaging material is reduced. Furthermore, by reducing the amount of material pushed toward the peripheral fin edge 310, a more robust and reliable lateral seal can be achieved.
[0053] Figure 7 shows an example of the peripheral fin edge 310 when the packaging material 102 used is provided with first and second weakening elements 604 and 606. Unlike the packaging material 102 shown in Figure 5, the packaging material 102 in this example consists of an outer protective layer 500, a cellulose substrate layer 502, a barrier layer 506, and an inner protective layer 504. The principle of forming the first and second offset edge bulges 600 and 602 using the first and second weakening elements 604 and 606 is also applicable to the packaging material 102 shown in Figure 5, but this principle may be more relevant to packaging materials 102 that include an aluminum foil layer as a barrier layer. This is because the aluminum foil layer is more susceptible to damage from stress and strain forces than, for example, the outer protective layer 500 or the inner protective layer 504.
[0054] In January 2023, the inventors conducted a test using a product filling machine to seal 1000ml capacity packages with an aluminum foil barrier layer using both the comparative packaging material shown in Figure 4 and the inventive packaging material shown in Figure 6. The results showed that the package according to the present invention exhibited fewer bulging problems at the fin edges compared to the comparative packaging material, with a difference of approximately 37% (Table 1).
[0055] [Table 1]
[0056] In April 2023, similar tests were conducted on a 200ml capacity packaging material with a fiber-based barrier layer. As a result, no swelling was observed in the packaging material of the present invention, while swelling was observed in the comparison product (12.5%), demonstrating a concrete reduction in the problem (Table 2).
[0057] [Table 2]
[0058] Figure 8 shows a fold line pattern that can be used to provide the first and second weakening elements 604, 606. As shown, unlike the fold line pattern of sheet 200 shown in Figure 2, the fold line pattern shown in Figure 8 provides the first and second weakening elements 604, 606 on the first bottom fin edge 206c of one sheet and the first upper fin edge 206a of another subsequent sheet. A first bend 800 may be provided on the first bottom fin edge 206c. A second bend region 802 may be provided on the first upper fin edge 206a. As shown, fold lines do not need to be provided on the first and second bends 800, 802. Omitting fold lines in these areas reduces the risk of damaging the packaging material 102.
[0059] The first weakening element 604 may be positioned at a first lateral distance TD1 from the peripheral fin edge 310, and the second weakening element 606 may be positioned at a second lateral distance TD2 from the peripheral fin edge 310. In other words, the first and second weakening elements 604 and 606 and the upper flap fold line 202a and the lower flap fold line 202c may be positioned with a gap between them.
[0060] As shown in Figure 9, the first and second weakening elements 604 and 606 may be provided on the packaging material 200 using a tool equipped with female and male dies 900 and 902. As shown in the figure, the outer inclination angle OS-A and the inner inclination angle IS-A may be different. More specifically, the inner inclination angle IS-A may be steeper than the outer inclination angle OS-A. The reverse configuration is also possible, that is, the outer inclination angle OS-A may be steeper than the inner inclination angle IS-A (not shown).
[0061] Figure 10 is a flowchart showing a method 1000 for manufacturing a sheet 200 of packaging material 102. This method includes a step 1002 of attaching an outer protective layer 500 and an inner protective layer 504 to a cellulose base layer 502, and a step 1004 of deforming the cellulose layer 502 to form first weakening elements 604 and second weakening elements 606 on the edges 206a to d of the sheet 200. The first and second weakening elements 604 and 606 may be positioned on different sides of the peripheral fin edge 310, separated by first and second lateral distances TD1 and TD2, respectively.
[0062] Figure 11 shows a method 1100 for manufacturing a package 116 from a sheet 200 of packaging material 102. In this method, the edges 206a to d of the sheet 200 are provided with a first weakening element 604 and a second weakening element 606 on different sides of the peripheral fin edge 310, at distances TD1 and TD2, respectively, from the peripheral fin edge 310. The method includes a step 1102 of supplying the sheet 200 and a step 1104 of folding and sealing the sheet 200 to form the fins 312, wherein the first and second weakening elements 604 and 606 are provided so that the bulge of the packaging material 102 is guided from the peripheral fin edge 310 toward the first and second weakening elements 604 and 606, respectively.
[0063] The problem of cracking in aluminum foil and other low-stretch packaging material layers has been mitigated in known solutions by adding fold lines that reduce stress on the packaging material, thereby reducing the risk of cracking and the resulting loss of packaging integrity. For example, it is known that fold lines are added to the intersections of longitudinal and transverse seals in packages to reduce stress on the low-stretch layers of the packaging material.
[0064] As described above, the method proposed herein allows the first and second weakening elements 604 and 606 to move material away from the peripheral fin edges 310, thereby preventing excess material (e.g., material from the inner protective layer of the packaging material) from forming a bulge 400 and reducing the risk of a decrease in seal quality. For example, as shown in Figure 5, if there is excess material on the peripheral fin edges 310, there is a risk of insufficient sealing, which may result in leakage from the package or failure to shield the food inside the package from the surrounding environment.
[0065] As is clear from the above description, various embodiments of the present invention have been described and shown, but the present invention is not limited thereto and can be embodied in other ways within the scope of the subject matter defined in the following claims.
Claims
1. A sheet (200) of packaging material (102) for a package (116) for holding food products (FP), wherein the packaging material (102) comprises an outer protective layer (500) positioned to face the surrounding environment, a cellulose layer (502), and an inner protective layer (504) for preventing contact between the food product (FP) and the cellulose layer (502), The aforementioned sheet (200) is The package (116) has at least one sealing portion (208, 210) arranged to be formed on the fin (312), the sealing portion (208, 210) comprises edges (206a to d) arranged to be formed on the peripheral fin edge (310) of the package (116), the peripheral fin edge (310) is formed by folding different sides facing each other and sealing the different sides together, thereby forming the fin (312). The edges (206a to d) are provided with a first weakening element (604) and a second weakening element (606) positioned on different sides of the peripheral fin edge (310) at distances of a first lateral distance (TD1) and a second lateral distance (TD2) from the peripheral fin edge (310), respectively, so that the material of the sheet (200) is pushed out from the peripheral fin edge (310) when bent, thereby providing a more reliable seal at the peripheral fin edge (310). Sheet (200).
2. No weakening element is provided in the bending region (800, 802) between the first weakening element (604) and the second weakening element (606). The sheet (200) according to claim 1.
3. The weakening elements (604, 606) are at least one of slits, holes, folds, or compression. The sheet (200) according to claim 1 or 2.
4. At least one sealing portion (208, 210) includes an upper sealing portion (208) and a lower sealing portion (210), the upper sealing portion (208) includes first and second upper fin edges (206a, 206b), and the lower sealing portion (210) includes first and second lower fin edges (206c, 206d). A sheet (200) according to any one of claims 1 to 3.
5. The packaging material (102) further includes a barrier layer (506) disposed between the cellulose layer (502) and the inner protective layer (504). A sheet (200) according to any one of claims 1 to 4.
6. The distance between the first and second weakening elements (604, 606) is 1 to 6 mm. A sheet (200) according to any one of claims 1 to 5.
7. The first and second weakening elements (604, 606) are provided using a tool that includes a female mold (900) and a male mold (902) whose outer inclination angle (OS-A) is steeper than the inner inclination angle (IS-A). A sheet (200) according to any one of claims 1, 2, 4 to 6.
8. The first and second weakening elements (604, 606) are provided using a tool that includes a female mold (900) and a male mold (902) whose inner inclination angle (IS-A) is steeper than the outer inclination angle (OS-A). A sheet (200) according to any one of claims 1, 2, 4 to 6.
9. A web of packaging material (102), comprising a plurality of successive sheets (200), wherein each sheet (200) is a sheet according to any one of claims 1 to 8. Web of packaging material (102).
10. A method (1000) for manufacturing a sheet (200) of packaging material (102), wherein the method is: A step (1002) of bonding an outer protective layer (500) and an inner protective layer (504) to a cellulose-based layer (502), The process includes the step of deforming (1004) the cellulose layer (502) to form first and second weakening elements (604, 606) on the edges (206a to d) of the sheet (200), wherein the first and second weakening elements (604, 606) are positioned on different sides of the peripheral fin edge (310) at distances of first and second lateral distances (TD1, TD2) from the peripheral fin edge (310), the peripheral fin edge (310) is formed by folding the different sides facing each other and sealing the different sides together to form a fin (312), and the material of the sheet (200) is pushed out from the peripheral fin edge (310) during folding to obtain a more reliable seal at the peripheral fin edge (310). Method (1000).
11. A method (1100) for manufacturing a package (116) from a sheet (200) of packaging material (102), wherein first and second weakening elements (604, 606) are provided on the edges (206a to d) of the sheet (200) at positions separated from the peripheral fin edges (310) by first and second lateral distances (TD1, TD2), the peripheral fin edges (310) are formed by folding the edges with different sides facing each other and sealing the edges together, and the method is, To supply the aforementioned sheet (200) (1102), The sheet (200) is folded and sealed (1104) to form a fin (312), and the first and second weakening elements (604, 606) are arranged so that the bulge of the packaging material (102) is guided toward the first and second weakening elements (604, 606) from the peripheral fin edge (310), thereby enabling a more reliable seal at the peripheral fin edge (310). Method (1100).
12. A package (116) obtained by the method (1100) of claim 11.