Method for manufacturing a pouch for holding a liquid therein and a pouch for holding a liquid therein

Abstract

The present invention provides a method of manufacturing a pouch for holding a liquid therein, the method comprising providing a front layer and a back layer, locally bonding the front layer and the back layer together to create an interior space, and forming an infusion channel by locally bonding the front layer and the back layer together to form a joint that defines a boundary of the infusion channel, the forming of the infusion channel being performed by providing a heating device having a plurality of heating elements arranged in a grid forming a heating surface, each of the heating elements being individually operable, operating the heating device such that the heating elements required to create the boundary are activated and thereby heated, and contacting the heating surface with the front layer or the back layer, thereby locally bonding the front layer and the back layer together to form a joint that defines a boundary of the infusion channel.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of European Patent Application No. 21174963.5, filed May 20, 2021, which is incorporated by reference in its entirety.

[0002] FIELD OF THEINVENTION The present invention relates to a method for manufacturing a pouch for holding a liquid therein. Further, the present invention relates to a pouch for holding a liquid therein and to the use of such a pouch. [Background technology]

[0003] US 2006 / 0182370 A1 relates to a flexible container for holding liquids, including two walls made of a flexible material, the overlapping free edges of which are assembled together by a welded or glued seam to define an inner sealed volume of the container. The two walls also define a spout. An obstacle formed by welding or joining the two walls together is disposed within the interior volume opposite and adjacent to the outflow channel. When liquid is present within the interior volume, a portion of the spout defined by the obstacle and the fold flexes.

[0004] Known pouches for holding edible liquids therein are made of front and back layers that define an interior space for holding the liquid therein. To pour the liquid out of the pouch, the pouch has an inlet made of a polymer block bonded between the front and back layers. The block has an inlet channel passing through the block and a closure element such as a plug or cap. Such pouches are relatively high in cost and relatively difficult to manufacture, mainly due to the design of the inlet. Instead of a polymer block, such pouches may have an inlet with a long and narrow inlet channel defined by melting the front and back layers together. However, it is difficult to manufacture such an inlet accurately.

[0005] The present invention addresses one or more of the problems set forth above. Summary of the Invention

[0006] In one aspect, the present invention relates to a method of making a pouch for holding a liquid therein, the method comprising: providing a front layer and a back layer; - locally bonding the front and back layers together in such a way that an interior space of the pouch between the front and back layers is created by the bonding, the interior space being configured to hold a liquid; - forming an injection channel by locally joining the front layer and the back layer together to form a joint that defines a boundary of the injection channel, the injection channel allowing liquid to flow out of the pouch from the interior space through the injection channel in an outflow direction, at least when the pouch is in use, in an open state of the injection channel; Forming the injection channel includes - providing a heating device having a plurality of heating elements arranged in a grid forming a heating surface, each heating element being individually operable to create a part of a junction defining a boundary of an injection channel; - operating the heating device such that the heating elements of the plurality of heating elements required for creating the boundary are operated and thereby heated; - contacting a heated surface with the front layer or the rear layer, thereby locally bonding the front and rear layers together to form a bond that defines the boundary of the injection channel.

[0007] The localized bonding to form the bonds that define the boundaries of the infusion channels may be performed subsequent to the localized bonding to create the internal space. In other embodiments, the bonding for the purpose of forming the infusion channels may be performed prior to, or at least partially simultaneously with, the bonding for the purpose of creating the internal space. The step of operating the heating device such that the element is heated is preferably performed prior to contacting the heating surface with the front layer or the back layer, but may be performed at least partially simultaneously therewith or thereafter.

[0008] In another aspect, the invention relates to a pouch for holding a liquid therein, the pouch being manufactured according to the manufacturing method according to the invention, the pouch having front and back layers joined together, and an interior space of the pouch between the front and back layers defined by the joining and configured to hold a liquid. The pouch comprises an inlet channel which, in use of the pouch, at least in an open state of the inlet channel, allows liquid to exit the pouch from the interior space through the inlet channel in an outlet direction. The inlet channel is formed by locally joining the front and back layers together to form a joint defining a boundary of the inlet channel.

[0009] In a further aspect, the invention relates to a pouch for holding a liquid therein, the pouch having front and back layers joined together, and an interior space of the pouch between the front and back layers defined by the join and configured to hold a liquid. The pouch comprises an infusion channel which, in use of the pouch, at least in an open state of the infusion channel, allows liquid to exit the pouch from the interior space through the infusion channel in an outflow direction. The infusion channel is formed by locally joining the front and back layers together to form a joint defining a boundary of the infusion channel, the infusion channel being designed such that, in use, the liquid flow resistance of the infusion channel is greater in an outflow direction opposite to the inflow direction, i.e. greater than in an inflow direction opposite to the outflow direction.

[0010] In yet another aspect, the invention relates to the use of such a pouch for holding a liquid therein.

[0011] In the following, some preferred features of the present invention are disclosed, which are applicable to the manufacturing method, the pouch and the use of the pouch according to the present invention.

[0012] The advantage of the method according to the invention is that, by the specific step of forming the inlet channel, a very precisely shaped inlet channel can be created between the front and back layers, including a relatively complex shape or channel layout, without the need for additional components such as the aforementioned block-shaped inlet. Thus, no additional elements are required and the pouch can be created using only the front and back layers, which can be a flexible single material. By doing so, a sustainable packaging design is obtained that is effective for the recycling stream. Such a precisely shaped inlet channel allows a great deal of control over the outflow of liquid from the pouch, for example allowing the inlet channel to be designed to obtain a valve-like behavior. The pouch produced in such a way has a very precise inlet, according to the invention, but is also low-cost and very easy and efficient to produce.

[0013] During the step of operating the heating device, the heating elements necessary for creating the boundaries of the injection channel are operated and thereby heated, while the remaining heating elements not necessary for creating such boundaries may not be operated and therefore may not be heated, such that at the locations of such remaining heating elements the front layer and the back layer are not bonded to each other.

[0014] As a result of contacting the heating surface with the front or back layer and operating the heating element, thereby heating the element, the front and back layers become locally welded to each other or locally heat sealed. Locally joining the front and back layers in such a way that the interior space of the pouch is created between the front and back layers can also be done by locally welding or heat sealing the layers.

[0015] In embodiments of the present invention, referring to the methods, pouches and uses according to the present invention, the infusion channel may be designed and formed by local bonding such that, when in use in an open state, the liquid flow resistance of the infusion channel is greater in the outflow direction than in the inflow direction opposite to the outflow direction. [Brief description of the drawings]

[0016] The present invention will now be described with reference to the accompanying schematic drawings, in which embodiments of the invention are shown and in which like reference numbers indicate the same or similar elements. [Figure 1] FIG. 1 is a front view showing an example of a pouch according to the present invention. [Figure 2a] FIG. 2 is a front view showing details of the pouch of FIG. 1. [Figure 2b] FIG. 2b shows the detail of FIG. 2a with the peel zone removed. [Diagram 3] An example of a method according to the present invention is given below. [Figure 4] 1 shows an example of a heating device for use in the method according to the invention. [Diagram 5] 5 shows the results of the method steps of the method according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Unless otherwise defined or specified, all terms should be given their technical meaning consistent with their ordinary meaning in the art as understood by those of ordinary skill in the art.

[0018] All parameter ranges include the endpoints of the range and all values ​​between the endpoints, unless otherwise specified.

[0019] As used in this specification and claims, the terms "comprise" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted as excluding the presence of other features, steps or components.

[0020] In this specification and claims, the term liquid is also considered to encompass emulsions, semi-liquids (including, for example, liquid butter, tomato sauce and mayonnaise). The liquid may be selected in embodiments of the present invention from the group consisting of hydrophilic liquids such as aqueous media, hydrophobic liquids such as oils, emulsions and more pasty materials such as tomato paste, liquid butter and mayonnaise, but also including herb pastes, toothpastes and cosmetic gels, the liquid being preferably an edible oil.

[0021] Each of the plurality of heating elements may have a length and a width, both in the range of 1-5 mm, at the heating surface and in the plane of the heating surface, which are preferably equal or at least substantially equal, e.g. 3 mm, and the grid forming the heating surface has at least 10 heating elements in the length and width direction, preferably 15-50 heating elements. The shape of the heating elements of the plurality of heating elements at the heating surface may be formed according to the required shape of the joint to be formed and thus the channel boundary, which allows for even greater precision.

[0022] Both the front and back layers may be made from a polymer selected from the group consisting of thermoplastic polymers or mixtures thereof, including copolymers, preferably selected from the group consisting of polypropylene (PP), polyethylene (PE), polyhydroxyalkanoate (PHA), and polylactic acid (PLA).

[0023] Preferably, the polymer is a polymer that can be heat sealed. In embodiments having a front layer and / or a back layer that is a multi-layer material, at least the inner layer comprises a polymer that can be heat sealed.

[0024] The particular injection channel design and manufacturing method of the present invention may be used with a variety of pouch designs, including not only the flat four side seal pouch design shown in the figures, but also gusseted pouches, such as, for example, three side seal pouches, upright pouches, and side gusset pouches.

[0025] The front and back layers as provided may in one embodiment be, or at least originate from, separate pieces of starting material, preferably the front layer being made of the same material as the back layer. The front and back layers as provided may in another embodiment be part of one integral piece of starting material. The latter means that the step of providing the front and back layers may be carried out by providing one integral sheet of material, one part of which constitutes the front layer of the pouch to be produced and another part of which constitutes the back layer of the pouch to be produced. Such an integral sheet of material may for example be folded to provide the front and back layers and then joined together at three overlapping edges (the fourth edge being at the fold), etc. Alternatively, it may be folded and glued, for example to obtain a pouch sealed in the middle.

[0026] The injection channel may have a main channel defining a main flow path in the outflow direction and may have multiple branch channels each branching off from the main channel, each of the multiple branch channels opening back to the main channel at least partially in a counterflow direction opposite to the outflow direction. Such a channel design is known under the name "Tesla valve". Such a channel design is disclosed, for example, in U.S. Pat. No. 1,329,559. Such an injection channel design may provide a significant and gradually increasing resistance in the outflow direction, which provides a highly controllable resistance. The multiple branch channels may be arranged on either side of the main channel, preferably in a staggered manner. In general, fewer such branch channels may be required for a relatively high viscosity liquid compared to a relatively low viscosity liquid.

[0027] The infusion channel may have an outflow opening through which the liquid can flow out of the pouch, and the infusion channel may be designed such that in the absence of an external force on the pouch, the liquid pressure at the outflow opening is below a predetermined threshold, meaning that when the pouch is not in use and is stored on a supporting surface such as a shelf, the liquid pressure is below the predetermined threshold.

[0028] The infusion channel may have an outflow opening through which liquid can flow out of the pouch, the infusion channel being designed such that the front and back layers at the outflow opening remain in contact with each other when the pressure of the liquid at the outflow opening in the outflow direction is below a predefined threshold. When the pressure of the liquid at the outflow opening in the outflow direction exceeds a threshold, the front and back layers are separated at the outflow opening, thereby allowing the liquid to flow out of the pouch. The front and back layers may remain in contact with each other at the outflow opening as a result of the elasticity of the layers as long as the pressure is below the threshold. In particular, using an infusion channel design with a main channel and a branch channel, this may be achieved in a controlled and predictable manner.

[0029] The pouch may further comprise a peel zone, in a first state of which it closes the liquid outflow opening of the infusion channel such that the infusion channel is in its closed state, and in a second state in which at least a part of the peel zone is removed by a user of the pouch, so that the infusion channel is in its open state and liquid may pour out of the pouch. Further peel zones may be defined in the pouch to peel off a part of the infusion channel to further reduce the flow resistance in the outflow direction. To this end, the pouch may comprise a peel initiation means such as a visual indicator and / or one or more recesses. For example, if more outflow is desired when applying a certain external pressure to the pouch, the user may peel off an additional peel zone, thereby peeling off a part of the infusion channel.

[0030] FIG. 1 shows a pouch 1 for holding a liquid therein. The liquid may be, for example, an edible substance such as edible oil or tomato paste. The pouch 1 has a front layer 2 and a back layer 3. The back layer is shown in the lower right corner of FIG. 1, and a part of the front layer is omitted in the drawing to show the back layer 3. The front layer 2 and the back layer 3 are joined together along their periphery in this embodiment, the joining being indicated by a dashed line 5. The joining referred to means the joining resulting from the joining, which defines an interior space 4 of the pouch between the front layer 2 and the back layer 3. The interior space 4 is configured to hold a liquid. The front layer and the back layer may be, for example, a polymer such as polypropylene. However, the material of the front layer and the back layer may be selected, for example, based on the properties of the liquid and based on the customer's requirements. The front layer and / or the back layer may be individually multi-layer products to meet the requirements for the inside, i.e. the internal space, and the outside of the pouch.

[0031] The pouch 1 comprises an inlet channel 6 (details of which are not shown in FIG. 1, see FIG. 2a) which, when the pouch 1 is in use, allows liquid to flow out of the pouch 1 from the interior space 4 via the inlet channel 6 in an outflow direction 8, at least in the open state of the inlet channel 6. For this purpose, the pouch 1 has a peel zone 10 which can be peeled off starting from a recess 12 in the form of a small cut-out portion for providing an intuitive starting point for peeling off the peel zone 10. FIG. 2b shows the pouch with the peel zone 10 removed. In its first original state, the peel zone 10 closes the liquid outflow opening 14 of the injection channel 6 such that the injection channel 6 is in its closed state, and the peel zone 10 has a second state in which at least a portion of the peel zone 10 has been removed by a user of the pouch 1 such that the injection channel 6 is in its open state and liquid can pour out of the pouch 1 through the now exposed outflow opening 14.

[0032] The infusion channel 6 is formed by locally heat sealing the front layer 2 and the back layer 3 together to form a joint 7 that defines the boundary of the infusion channel 6. The localized bonding to form the infusion channel may be performed subsequent to the bonding described above to define the interior space. In other embodiments, the bonding for the purpose of forming the infusion channel may be performed prior to or at least partially simultaneously with the bonding for the purpose of defining the interior space. The infusion channel 6 is designed such that, in use, the flow resistance of the infusion channel 6 is greater in the outflow direction 8 than in the inflow direction 9 opposite the outflow direction 8. This is achieved by designing the infusion channel 6 to have a main channel 16 through which the liquid in use flows in the outflow direction 8, and a number of branch channels 20 each branching off from the main channel 16, each of the multiple branch channels 20 opening back into the main channel 16 in a counterflow direction 22 at least partially opposite the outflow direction 8. See FIG. 2a. The inlet channel 6 has a free downstream end forming an outlet opening 14 through which liquid can exit the pouch 1, the inlet channel 6 being designed such that in the absence of external forces on the pouch, the pressure of the liquid at the outlet opening 14 is below a predefined threshold value. This can be achieved by the specific inlet channel design as described above.

[0033] Optionally, there may be further peel-off zones from further recesses 12' if desired, such as to further reduce the outflow resistance. In the embodiment shown in Figure 2a, recesses 12' provide for the peel-off of the two most downstream branch channels 20.

[0034] A pouch such as pouch 1 described above can be efficiently and easily manufactured by a method of manufacturing a pouch for holding a liquid therein, which can include the following. - Providing a front layer 2 and a back layer 3 (step S1 in FIG. 3). - locally bonding the front layer 2 and the back layer 3 together in such a way that an interior space 4 of the pouch 1 between them is created by the bond, the interior space 4 being configured to hold a liquid (step S2). Such local bonding may be performed by contacting a heated surface with the front layer 2 or the back layer 3, thereby locally bonding the front layer 2 and the back layer 3 together to form a bond that defines the interior space 4. For example, the bond may be made along the periphery of the pouch to be formed. - forming an injection channel 6 (step S3) by locally joining the front layer 2 and the back layer 3 so as to form a joint 7 that defines the boundary of the injection channel 6, which allows liquid to flow out of the pouch 1 from the interior space 4 via the injection channel in an outflow direction 8, at least in the open state of the injection channel 6 as described above (step S3).

[0035] The formation of the injection channel 6 can be carried out by: - Providing a heating device 30 having a plurality of heating elements 32 arranged in a grid, as shown in FIG. 4, which form a heating surface 34, each of the heating elements 32 being individually operable to create part of a junction 7 defining the boundary of the injection channel 6 (step S3a). - operating the heating device 30 (step S3b) such that the heating elements 32 of the plurality of heating elements required for creating the boundary are operated and thereby heated. Thus, the heating elements of the plurality of heating elements that are not required for creating the boundary are not operated and therefore not heated. - bringing a heated surface 34 into contact with the front layer 2 or the back layer 3, for example the front layer 2, thereby locally joining the front layer 2 and the back layer 3 together by welding or heat sealing so as to form a joint 7 that defines the boundary of the injection channel 6 (step S3c). This is shown diagrammatically in Figure 5, where the injection channel is defined by a zone where the front and back layers are not joined. Figure 5 shows the manufacturing principle of the pouch according to the invention. In contrast to the pouch shown in Figures 2a and 2b, in Figure 5 an injection channel with three branch channels 20 is depicted.

[0036] In another embodiment, step S2 is performed simultaneously with step S3. In a further embodiment, step S3 is performed before step S2. Also, the performance of steps S2 and S3 may partially overlap. The step of operating the heating device such that the element is heated is preferably performed before contacting the heating surface with the front layer or the back layer, but may be performed at least partially simultaneously therewith or after.

[0037] The heating elements of the heating device 30 have a length L and a width W in the heating surface 34 and in the plane of the heating surface 34. Both the length L and the width W may be in the range of 1-5 mm, preferably equal to 3 mm, where the grid forming the heating surface 34 has at least 10 heating elements 32 in the length and width directions, preferably 15-50.

[0038] Although specific embodiments of the present invention have been described, the appended claims are not intended to be limiting to the examples only, and the claims should be construed literally, tangibly, and / or to encompass equivalents.

Claims

1. 1. A method for manufacturing a pouch (1) for holding a liquid therein, said method comprising the steps of: - providing a front layer (2) and a back layer (3); - locally joining said front layer and said back layer together in such a way that an internal space (4) of the pouch between said front layer and said back layer is created by the joining, said internal space being adapted to hold said liquid; forming an injection channel (6) by locally joining said front layer and said back layer together to form a joint (7) that defines the boundary of said injection channel, said injection channel allowing, at least when the pouch is in use, in an open state of said injection channel, liquid to flow out of said pouch from said interior space through said injection channel in an outflow direction (8); forming the injection channel - providing a heating device (30) having a plurality of heating elements (32) arranged in a grid forming a heating surface (34), each of said heating elements being individually operable to create a part of a junction (7) defining the boundary of said injection channel; - operating said heating device (30) so that those heating elements of said plurality of heating elements necessary for creating said boundary are activated and thereby heated; - contacting said heated surface (34) with said front layer or said rear layer, thereby locally bonding said front layer and said rear layer together to form said joint (7) defining said boundary of said injection channel (6).

2. 2. The method of claim 1, wherein each of said plurality of heating elements (32) has a length (L) and a width (w) at said heating surface (34) and in the plane of said heating surface, both in the range of 1 to 5 mm, said lengths and widths being preferably equal, and wherein a grid forming said heating surface comprises at least 10 heating elements in the length and width directions, preferably 15 to 50 heating elements.

3. 2. The method of claim 1, wherein the injection channel is designed such that, when in use in the open state, the injection channel has a greater liquid flow resistance in the outflow direction (8) than in an inflow direction (9) opposite to the outflow direction.

4. 2. The method of claim 1, wherein the front layer and the back layer are both made from a polymer selected from the group consisting of thermoplastic polymers or mixtures thereof, including copolymers, preferably selected from the group consisting of polypropylene (PP), polyethylene (PE), polyhydroxyalkanoates (PHA), and polylactic acid (PLA).

5. 1. A pouch (1) for holding a liquid therein, the pouch being manufactured according to the method of claim 1, the pouch having a front layer (2) and a back layer (3) joined together, and an interior space (4) of the pouch between the front and back layers defined by said joining and configured to hold said liquid, the pouch comprising an injection channel (6) which, when the pouch is in use, at least in an open state of the injection channel, allows liquid to exit the pouch from the interior space through the injection channel in an outflow direction (8), the injection channel being formed by locally joining the front and back layers together to form a joint (7) defining the boundary of the injection channel.

6. 6. The pouch of claim 5, wherein the infusion channel is designed and formed by the localized bonding such that, when in use in the open state, the infusion channel has a greater liquid flow resistance in the outflow direction than in an inflow direction opposite to the outflow direction.

7. 6. The pouch of claim 5, wherein the injection channel comprises a main channel (16) through which liquid can flow in the outflow direction (8) and a plurality of branch channels (20) each branching off from the main channel, each of the plurality of branch channels opening back into the main channel at least partially in a counterflow direction (22) opposite the outflow direction.

8. 6. The pouch of claim 5, wherein the injection channel has an outflow opening (14) through which the liquid can flow out of the pouch, and wherein the injection channel is designed such that the front and back layers at the outflow opening remain in contact with each other when the pressure of the liquid at the outflow opening in the outflow direction is below a predetermined threshold, and a pressure of the liquid at the outflow opening in the outflow direction exceeding the threshold causes the front and back layers to separate at the outflow opening, thereby allowing liquid to flow out of the pouch.

9. 6. The pouch of claim 5, further comprising a peel-off zone (10) which in a first state closes a liquid outflow opening (14) of the injection channel such that the injection channel is in its closed state, and which has a second state in which at least a portion of the peel-off zone (10) is removed by a user of the pouch, so that the injection channel is in its open state and liquid can pour out of the pouch.

10. A pouch (1) for holding a liquid therein, comprising a front layer (2) and a back layer joined together, and an interior space (4) of the pouch between said front and back layers defined by said joining and configured to hold said liquid, said pouch comprising an injection channel (6) which, in use of the pouch, at least in an open state of said injection channel, allows liquid to flow out of the pouch from said interior space through said injection channel in an outflow direction, said injection channel being formed by locally joining said front and back layers together to form a joint defining the boundary of said injection channel, The pouch (1), wherein the infusion channel is designed such that, in use, the infusion channel has a greater liquid flow resistance in the outflow direction (8) than in an inflow direction (9) opposite to the outflow direction.

11. 11. The pouch of claim 10, wherein the inlet channel comprises a main channel (16) through which liquid can flow in the outlet direction (8) and a plurality of branch channels (20) each branching off from the main channel, each of the plurality of branch channels opening back into the main channel at least partially in a counterflow direction (22) opposite the outlet direction.

12. 11. Use of a pouch according to claim 5 or claim 10 for holding a liquid therein.

13. 13. The use according to claim 12, wherein the liquid is selected from the group consisting of hydrophilic liquids such as aqueous media, hydrophobic liquids such as oils, and more pasty materials such as tomato paste, liquid butter, and mayonnaise, but also including herb pastes, toothpaste, cosmetic gels, the liquid being preferably an edible oil.

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