Method for forming a container from a fiber-based wall portion and a frame structure, and a container

Abstract

Disclosed herein is a method (400) for forming a shoulder (110) on a container (100) comprising a fiber-based wall portion (120) and a frame structure (130). The method comprises the steps of inserting a precut sheet (125) of fiber‐ based material into a female mould (210) to form the wall portion (120), inserting a corresponding male mould (220) into the female mould (210), injecting a liquid polymer (230) into a first cavity (310) formed between the precut sheet (125) and the male mould (220) or the female mould (210), to form the frame structure (130), injecting liquid polymer (230) into a second cavity (320) formed in the male mould (220), forcing the precut sheet (125) of fiber‐based material to deform into at least one third cavity (330) arranged in the female mould (210) such that the shoulder (110) is formed in the wall portion (120), extending outwards from the fiber‐based wall portion (120). There is also disclosed a container (100) comprising a fiber‐based wall portion (120) and a frame structure (130).

Description

[0001] METHOD FOR FORMING A CONTAINER FROM A FIBER-BASED WALL PORTION AND A FRAME STRUCTURE, AND A CONTAINER

[0002] Technical Field

[0003] The present invention generally relates to containers, and more specifically to a method for forming a container from a fiber-based wall portion and a frame structure.

[0004] Background

[0005] Containers are widely used in a range of industries, for example within the food industry. Those containers are often disposable containers made from a plastic material, which are incinerated or recycled after use. While plastic containers are easy to manufacture, safe and convinient to use, they are often made from a fossil based material and this generates CO2 emissions. However, it is difficult to find a replacement to plastic materials that is equally durable, lightweight, versatile, cheap and at the same time environmentally friendly.

[0006] An alternative solution is to use a hybrid combination of materials, where fiber-based material may be used in combination with a plastic material, and by combining their properties, the use of fossil plastic materials in containers can be minimized, while keeping the characteristics that are difficult to replace with another material. One such hybrid is for example paper and plastic.

[0007] Moreover, containers are typically manufactured in one facility, and transported in batches to another facility where they are filled with the intended content. To effectivise transportation, the empty containers are usually stacked in each other, to save space.

[0008] However, a problem with transporting large stacks of containers is that the containers gets stuck inside each other. As the amount of containers in a stack increases, the load on each container increases further down in the stack, why the containers in the stack are pressed into each other with an increased force until they are jammed and thereby stuck to each other. Thus, when the stack of containers arrive to the facility where they are intended to be filled, there may occur a problem with separating the stacked containers into individual containers, why the containers may be damaged or discarded. This may lead to stalls in the production, monetary losses and an increased material waste.

[0009] Summary

[0010] In the light of the above, it is desired to provide alternative solutions in order to overcome the problem of separating stacked, empty containers. These and other objects are achieved by providing an improved method for forming a shoulder on a container comprising a fiber-based wall portion and a frame structure, having the features in the independent claims. Preferred embodiments are defined in the dependent claims.

[0011] Hence, according to a first aspect of the present invention, there is provided a method for forming a shoulder on a container comprising a fiber-based wall portion and a frame structure. The method comprises the steps of inserting a precut sheet of fiber-based material into a female mould to form the wall portion, the female mould having a shape corresponding to the intended shape of the container. The method further comprises the step of inserting a corresponding male mould into the female mould, the precut sheet being sandwiched between the female and male mould. The method further comprises the step of injecting a liquid polymer into a first cavity formed between the precut sheet and the male mould or the female mould, to form the frame structure. The method further comprises the step of injecting liquid polymer into a second cavity formed in the male mould, said second cavity is arranged in a position corresponding to the position of the shoulder on the container, thereby forcing the precut sheet of fiber-based material to deform into at least one third cavity arranged in the female mould in a position corresponding to desired position of the shoulder such that the shoulder is formed in the wall portion, extending outwards from the fiber-based wall portion.

[0012] According to a second aspect of the present invention, there is provided a container formed by the method according to the first aspect of the present invention. The container comprises a base portion and a top portion, and a wall portion made from a fiber-based material and extending from said base portion to the top portion. The container further comprises a frame structure extending from the base portion to the top portion and supporting said wall portion, wherein the wall portion is configured to enclose said frame structure, and a shoulder arranged in the wall portion, extending outwards from the wall portion.

[0013] There are a number of advantages associated with the method according to the present invention. For example, the method allows for a complex shape to be advantageously formed in a fiber-based container, while reducing the amount of a plastic material in each container. Typically, complex shapes, such as shoulders, are difficult to create in fiber-based materials, due to their decreased level of moldability in comparison to a plastic material, why containers requiruing complex shapes are often formed entirely from a plastic material. Alternatively, simpler shapes are used in fiber-based containers, however with the consequence of being applicable in less applications. The container formed by the method allows for both a complex shape, as well as a container being formed from a majority of fiber-based material. Thus, the method is beneficial from an environmental perspective, since the amount of plastic material may be reduced in the container, while maintaining the functionality of a container formed entirely from a plastic material.

[0014] The precut sheet of fiber-based material may be precut in a shape corresponding to that of the intended shape of the wall portion. Moreover, the precut sheet of fiber-based material may have pre-creased fold lines. For example, the precut sheet of fiber-based material may be a flat sheet before being arranged in the female mould, and thus having a shape corresponding to the intended shape of the container in a flattened form. The precut sheet of fiber-based material may for example be made from a paper material, such as carton. In one example, the finished container may be intended to receive a liquid content. The fiber-based material may therefore preferrably be made from a paper material coated with a plastic film, forming a liquid barrier which may prevent the liquid content to seep into the paper material of the wall portion. Thus, when the precut sheet of fiberbased material is inserted in the female mould, the sheet may be folded at the precreased fold lines to fit into the female mould which has a shape corresponding to the intended shape of the container.

[0015] By "container" is herein meant a hollow object, used for holding something for the reason of carrying or storing it. The container may for example be a type of box or a bottle. The container may either be a disposable container, or a reusable container. Further, the container may be intended to receive a lid to secure the contents stored therein.

[0016] By "female mould" is herein meant a negative mould, i.e. a concave mould. The female mould is formed from a material suitable for receiving a polymer, and more specifically a liquid polymer of a high temperature and / or pressure. Furthermore, the polymer is injected into the female mould, and thus the inner dimensions of the female mould correspond to the outer dimensions of the part formed therein, and in the context of the present disclosure, the outer dimensions of the container.

[0017] By "male mould" is herein meant a positive mould, i.e. a convex mould. The male mould is formed from a material suitable for receiving a polymer, and more specifically a liquid polymer of a high temperature and / or pressure. Furthermore, the polymer is draped onto the male mould, and thus the outer dimensions of the male mould correspond to the inner dimensions of the part formed thereon, and in the context of the present disclosure, the inner dimensions of the container.

[0018] According to one exemplifying embodiment of the present disclosure, the container comprises a base portion and a top portion, said top portion comprising an open end, and wherein the wall portion extends from the base portion to the top portion. Thus, a hollow shape may be formed by the base portion and the wall portion together defining a hollow space. The top portion may be an open portion, allowing access into the hollow space of the container. The precut sheet may constitute a majority of the base portion and the wall portion. The base portion may be arranged in the bottom of the female mould, i.e. in the bottom of the hollow shape, and the top portion may be arranged in the top of the female mould, opposite to the bottom. The base portion and top portion may have similar shapes.

[0019] According to one exemplifying embodiment of the present disclosure, a size of the top portion is larger than a size of the base portion, and wherein the wall portion extends from the base portion at an angle, said angle being relative a vertical axis extending between the base portion and the top portion. The base portion and the top portion may be parallel with each other. In one example, the base portion and the top portion may be arranged in horizontal planes, along a vertical axis. The area defined by the base portion may be smaller than an area defined by the top portion. Moreover, the wall portion may be arranged around a periphery of the base portion, and extending from the base portion towards the top portion. Further, the wall portion may be arranged around a periphery of the top portion. Since the base portion has a smaller size than the top portion, the wall portion extending from the base portion to the top portion may be slanted, and thus arranged at an angle from the vertical axis extending from the base portion to the top portion. The angle may be in a range from 1 to 75 degrees, but preferably in a range between 1 to 20 degrees. The present embodiment is advantageous in that it allows for the container to be removed from the female mould when it has been formed. The slanted wall portion enables the container to be removed from the female mould while preventing it from getting stuck therein.

[0020] According to one exemplifying embodiment of the present disclosure, the base portion comprises a circular shape having a first diameter, and the top portion comprises a circular shape having a second diameter. The first diameter may thus be larger than the second diameter. The container may thus have the shape of a truncated cone, with a flat base portion and top portion, connected by the slanted wall portion. Moreover, the container may thus have a circular cross-section in the horizontal plane. In the case where the base portion and top portion are circular, the female mould and the male mould may have a corresponding shape with a circular cross-section as well.

[0021] In another exemplifying embodiment, the container may be substantially rectangular, with a rectangular base portion and rectangular top portion. It will be appreciated that the container may have any shape suitable for being formed by a precut sheet of fiber-based material and a frame structure made from a liquid polymer.

[0022] The female mould may thus have a shape corresponding to the intended shape of the container. The female mould may comprise a shoulder portion corresponding to that of the finished container. Thus, since the female mould is a negative mould, the shoulder portion in the female mould may be a cavity in the wall of the female mould, protruding into the wall of the female mould, such that a negative shape is formed. The male mould may be arranged inside the female mould, the male mould having a shape corresponding to the female mould. For example, if the female mould has the hollow shape of a cup with a circular crosssection, the male mould may have a convex shape of a cup with a circular cross- section. The male mould may have a convex size that is slighly smaller than the size of the hollow in the female mould such that a gap is formed between the female mould and the male mould. The gap may fit the pre-cut sheet of fiber-based material, which is arranged in the female mould.

[0023] When the male mould has been arranged inside the female mould, the liquid polymer may be injected into a first cavity formed between the precut sheet and the female mould, alternatively between the precut sheet and the male mould. The first caivty may thus be the gap formed between the female mould and the male mould when the male mould is arranged inside the female mould.

[0024] According to one exemplifying embodiment of the present disclosure, the first cavity has a depth d, the depth d being in a range of 0.1 mm to 5 mm, and preferably between 0.1 mm to 0.7 mm. the depth d of the first cavity may be measured as the distance between the male mould and the female mould when they are arranged together, i.e. the male mould is inserted into the female mould. The depth d of the first cavity may be adjusted depending on the desired thickness of the wall portion, which may be dependent on the thickness of the precut sheet. The depth may be adjusted by adjusting the size of the male mould that is inserted into the female mould. By increasing the size of the male mould, the depth d may be decreased, and vice versa, if the size of the male mould is decreased, the depth d may be increased. Different manufacturers may produce different precut sheets, with different thicknesses, why different depths d may be desired. Further, the depth d of the first cavity may determine the thickness of the frame structure. This advantageously allows for different types of polymers to be used for forming the container. Different polymers may have different characteristics, and may thus require different thicknesses in order to deliver the same end results in terms of strength or durability.

[0025] According to one exemplifying embodiment of the present disclosure, the liquid polymer is injected into the first cavity through the base portion of the container. The liquid polymer may be injected into the first cavity through injection moulding. Generally, injection moulding works by polymer granules or pellets being heated and melted into a liquid. The liquid polymer is then fed to and pressurized by a reciprocating screw, for example, whereafter it is injected into a mould cavity, where it cools and hardens to the configuration of the cavity. The liquid polymer may thus be injected through an aperture in the base portion of the container. In the embodiment where the base portion is circular, the aperture may be arranged in the center of the circle. In the example where the first cavity is arranged between the male mould and the precut sheet, an injection tool may be used to pierce a hole through the precut sheet in the base portion, and inject the liquid polymer between the male mould and the precut sheet. In this embodiment, the frame structure may be formed on an inner surface of the finished container. In the example where the first cavity is arranged between the female mould and the precut sheet, an injection mould may be arranged to inject the liquid polymer between the female mould and the precut sheet in the base portion. In this embodiment, the frame structure may be formed on an outer surface of the finished container. Injecting the liquid polymer from the base portion is advantageous in that it enables the liquid polymer to flow through the first cavity from one position. When the liquid polymer flows from the base portion from one position, this enables symmetry in the frame structure, since there is only one source of liquid polymer, where the pressure and velocity of the liquid polymer entering the female mould may be advantageously controlled. The liquid polymer may therefore propagate upwards towards the top portion in a controlled way. Furthermore, it is desirable to press out any air situated in the first, second and third cavities while injecting the liquid polymer. Injecting the liquid polymer from the base portion and letting it propagate upwards towards the open top portion is therefore advantageous since it allows air to escape through the top portion, and preventing it from getting stuck and possibly forming air bubbles in the frame structure.

[0026] According to one exemplifying embodiment of the present disclosure, the frame structure comprises a frame base portion and a frame top portion corresponding to the shape of the base portion and the top portion of the container, and at least one leg extending from the frame base portion to the frame top portion. The first cavity may thus be formed by a number of paths having the shape of the frame structure. For example, the precut sheet, in its folded position in the female mould, may have edges that needs to be sealed in order to create a sealed hollow space in the container. The first cavity may be aligned with those edges such that the liquid polymer seals the edges when it is flowing through the first cavity. For example, the frame base portion of the frame structure may extend around the periphery of the base portion of the container. Similarly, the frame top portion of the frame structure may extend around the periphery of the top portion of the container. Moreover, the at least one leg may be comprised by a plurality of legs, distributed around the periphery of the frame base portion and extending from the frame base portion to the frame top portion. The legs may function as a path for the liquid polymer to travel in order to reach the second cavity. Thus, the frame structure may provide a supporting structure in the wall portion, by adding a harder material than the fiber-based material of the precut sheet to stabilize the wall portion. Further, the frame structure provides sealing, stability, and a controlled way for the liquid polymer to reach the second cavity.

[0027] The liquid polymer may reach the second cavity through the first cavity. In the example where the frame structure comprises at least one leg, the liquid polymer may flow through the at least one leg of the first cavity and reach the second cavity. The second cavity may be arranged in the male mould, in a position thereon corresponding to the desired position of the shoulder. The second cavity may be a cavity formed in the male mould, thus a depression in the male mould. The desired position of the shoulder may for example be along the vertical axis, closer to the top portion than the base portion. In one example, the shoulder is a separate part, not forming part of the top portion. The container may have a height h, defined by the length of the vertical axis between the base portion and the top portion. The shoulder may for example be arranged at 3 / 4 of the height of the container, from the base portion. In another example, the shoulder may be arranged at 2 / 3 of the height of the container, from the base portion. In an even further example, the shoulder may be arranged at 4 / 5 of the height of the container, from the base portion. Arranging the top portion of the container and the shoulder to be separate parts is advantageous in that it enables a greater freedom in designing the container, since a manufacturer may adapt the height of the shoulder to their own preferences.

[0028] Furthermore, a third cavity may be arranged in the female mould in a position corresponding to the desired position of the shoulder. The third cavity and the second cavity may thus be aligned along the vertical axis. The third cavity may be a depression in the female mould, thus extending into the walls of the female mould. When the liquid polymer flow through the first cavity and reaches the second cavity, the liquid polymer may fill the second cavity, which results in a pressure being built up in the second cavity. In the case where the first cavity is arranged between the male mould and the precut sheet, the pressure buildup in the second cavity may press the precut sheet outwards, from the male mould, thereby deforming the precut sheet.

[0029] According to one exemplifying embodiment of the present disclosure, the second cavity has a depth D, the depth D being greater than the depth d of the first cavity. This is advantageous in that it enables liquid polymer to be built up inside the second cavity to create the pressure necessary to deform the precut sheet to be pressed outwards from the male mould.

[0030] Since the position of the third cavity may be aligned with the position of the second cavity, the precut sheet may deform into the third cavity when the liquid polymer in the second cavity presses the precut sheet away from the male mould. Thus, a shoulder may be formed by the precut sheet being pressed into the third cavity in the female mould, the third cavity having the shape of the shoulder. When the liquid polymer hardens, the precut sheet may be permanently deformed in the third cavity, and thereby a shoulder is formed. This is advantageous in that the liquid polymer enables deforming of the precut sheet of fiber-based material into a complex shape, which would not have been possible only using the fiber-based material.

[0031] Furthermore, the shoulder enables a way for two or more containers to be stacked on top of each other, while preventing them from being stuck inside each other. Since the shoulder protrudes outwards from the wall portion of the container, the shoulder may act as a spacer between two or more containers stacked on top of each other, such that a first container arranged inside a second container may not be fully arranged inside the second container. The shoulder of the first container may abut the top portion of the second container, such that the first container is prevented from being fully arranged inside the second container. The shoulder may thus provide a spacer between each pair of containers in a stack. Thus, the area of the cross-section of the container at the height of the shoulder may be larger than the area of the cross-section of the container at the top portion. This prevents the first container to be fully arranged inside the second container. Furthermore, since the first container may not be fully arranged in the second container, there may be an air gap between the first and the second container in the stack, enabled by the shoulder. Thus, when multiple containers are stacked on top of each other, it prevents them from being jammed and get stuck inside each other, since the shoulder may prevent the containers to be fully arranged inside each other in the stack. This means that containers may be advantageously stacked on top of each other without getting stuck inside each other. This is beneficial since it decreases the risk of containers being damaged due to that they are not separable. Further, the risk of having to discard containers that were intended to be filled with a product is decreased, leading to an increased efficiency in production at the facility receiving the containers. Thus, the containers may be easier to separate, and the "vacuumlike" effect may be prevented from occurring since the air gap between the containers may be remained due to the shoulder forming a spacer between each pair of containers in the stack. This is further advantageous in that the amount of containers needed to be discarded may decrease, while maintaining the effectivity of transporting empty containers in stacks.

[0032] The "width" of the spacer, meaning the distance between the top portions of two containers stacked on top of each other, may vary depending on where the shoulder is arranged on the wall portion. As discussed above, the shoulder may be arranged along the height h of the container, along the vertical axis between the base portion and the top portion. The closer to the top portion the shoulder is arranged, the lesser the "width" of the spacer will be, i.e., decreasing the distance between the top portions of two containers stacked on top of each other. Vice versa, the closer to the base portion the shoulder is arranged, the greater the "width" of the spacer will be, increasing the distance between the top portions of two containers stacked on top of each other. An advantage with decreasing the distance between the top portions of two stacked containers is that the total height of the stack will be decreased, meaning that the containers may be stacked in a more space efficient manner, facilitating the transportation and / or storage of containers. However, a drawback with decreasing the distance between the top portion of two containers stacked on top of each other, is the increased risk of the "vacuum-like" effect discussed above, meaning that it may be difficult to separate the containers in a stack. Therefore, an advantage with increasing the distance between top portions of two containers stacked on top of each other is that the air gap formed between the stacked containers may be increased, in its turn facilitating the separation of containers stacked on top of each other. The air gap between the containers may ensure to prevent the "vacuum-like" even when pressure is exerted on the stack of containers. This may in its turn facilitate during filling of the containers in a production line, for example, where less force is needed to separate the containers one-by-one and transport them to the next step in the production line, for example filling of the containers.

[0033] According to one exemplifying embodiment of the present disclosure, the shoulder has a triangular profile relative the wall portion, and wherein at least one of the sides of the triangular profile is parallel to the vertical axis. The shoulder may thus extend outwards from the wall portion of the container, and in a vertical crosssection, the shoulder may have a triangular profile. In the embodiment where the wall portion is slanted, the wall portion may not be the side of the triangular profile being parallel with the vertical axis. The triangular shape may be beneficial to form the air gap between two or more containers in a stack.

[0034] According to one exemplifying embodiment of the present disclosure, the shoulder is continuously arranged around a periphery of the wall portion. This is beneficial since it may form a continuous spacer between two or more containers in a stack. The continuous shoulder may increase the stability and the strength of the shoulder, such that an increased amount of containers may be stacked on top of each other without increasing the risk of the shoulder being impaired and losing its functionality as a spacer.

[0035] According to one exemplifying embodiment of the present disclosure, the at least one third cavity is a plurality of cavities, and the shoulder comprises a plurality of shoulder portions extending outwards from the fiber-based wall portion. The third cavities may be arranged in the same position along the vertical axis, and distributed around the periphery of the wall portion. According to one exemplifying embodiment of the present disclosure, the plurality of shoulder portions are distributed around a periphery of the wall portion. The present embodiment is advantageous since a decreased amount of liquid polymer may be used. According to one exemplifying embodiment of the present disclosure, the method further comprises the step of injecting liquid polymer into a fourth cavity between the male mould and the female mould, to form a flange around a periphery of the container at the top portion. The fourth cavity may be arranged in the top portion of the container. Thus, the flange may be a flange around the periphery of the top portion of the container, extending outwards from the wall portion. The flange may comprise a flat surface, and extend from the top portion in one plane, i.e. the horizontal plane. A flange is advantageous since it may form a grip for a toolor a person separating the stacked containers upon arrival to the facility where the containers should be filled. Further, the flange may form a grip for a lid to seal the container. The flat surface of the flange may further provide a surface for sealing a film to the top portion of the container. For example, the container may be filled with a liquid product, such as yoghurt, and a film, e.g. a plastic film, may be fused onto the flat surface of the flange, thereby sealing the liquid inside the container. A lid may then be arranged on the container, around the flange, to provide a second seal.

[0036] Brief of the

[0037] Exemplifying embodiments will now be described in more detail, with reference to the following appended drawings:

[0038] Figures la-lc schematically illustrates different steps in a method for forming a shoulder on a container according to an exemplifying embodiment of the present disclosure;

[0039] Figures 2a-2b schematically illustrate a detailed view of a shoulder, a top portion and a base portion in a container according to an exemplifying embodiment of the present disclosure;

[0040] Figure 3 schematically illustrates a container according to an exemplifying embodiment of the present disclosure;

[0041] Figure 4 schematically illustrates a precut sheet of a fiber-based material according to an exemplifying embodiment of the present disclosure;

[0042] Figures 5a-5b schematically illustrate a shoulder arranged on a container according to an exemplifying embodiment of the present disclosure; Figure 6 schematically illustrates a frame structure of a container according to an exemplifying embodiment of the present disclosure;

[0043] Figure 7 schematically illustrates a stack of containers according to an exemplifying embodiment of the present disclosure;

[0044] Figure 8 schematically illustrates a method for forming a shoulder on a container according to an exemplifying embodiment of the present disclosure.

[0045] Detailed Description

[0046] As illustrated in the figures, the size of the elements and regions may be exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of the embodiments. Like reference numerals refer to like elements throughout.

[0047] Exemplifying embodiments will now be described more fully hereinafter with reference to the accompanying figures, in which currently preferred embodiments are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0048] With reference to figures la-lc, different steps in a method for forming a shoulder 110 on a container 100 according to an exemplifying embodiment of the present disclosure is shown. The steps are portrayed by a cross-section of a precut sheet 125 of a fiber-based material arranged between a female mould 210 and a male mould 220. The cross-section is a vertical cross section, and a vertical centerline A bounds the view to the left in the figures la-lc. The cross-section is symmetrical, why the right side of the centerline A contains the same, mirrored view. A female mould 210 is shown, enclosing a hollow shape 210'. The hollow shape 210' has the same shape as the intended shape of the container (not shown). Inside the female mould 210 a male mould 220 is arranged. The male mould 220 has a convex shape, corresponding to the shape of the hollow space 210' of the female mould 210. The female mould 210 and the male mould 210 define a space between them, wherein a precut sheet 125 of fiber-based material is arranged. The precut sheet 125 is folded and rests on a bottom wall 211 and along a wall 212 of the female mould 210. Furthermore, the precut sheet 125 and the male mould 220 defines a first cavity 310 between them. The male mould 220 further comprises a second cavity 320, hollowed out from a wall 221 of the male mould 220. The female mould 210 comprises a third cavity 330, hollowed out from the wall 212. The female mould 210 further comprises a fourth cavity 340, hollowed out from a top 213 of the female mould 210. Further, the wall 212 of the female mould 210 is parallel to the wall 221 of the male mould 220.

[0049] With reference to fig. la, the method for forming a shoulder (not shown) on a container (not shown) is shown in a step where the precut sheet 125 has been inserted into the female mould 210. The precut sheet 125 rests against the wall 212 of the female mould 210 which has the shape corresponding to the intended shape of the container (not shown). Thus, the precut sheet 125 inserted into the female mould 210 forms the wall portion 120 of the container (not shown). Further, the male mould 220 has been partly arranged in the female mould 210, as shown in fig. la.

[0050] With reference to fig. lb, the method for forming a shoulder on a container is shown in a step where the male mould 220 has been fully inserted into the female mould 210. The position of the female mould 210 and the male mould 220 in the present figure corresponds to the position of the moulds before a liquid polymer (not shown) may be injected into the first cavity 310. The first cavity 310 has a depth d, measured from the precut sheet 125 to the wall 221 of the male mould 220. The first cavity 310 extends from the bottom 211 of the female mould 210, and further along the wall portion 120 until the first cavity 310 reaches the second cavity 320. The second cavity 320 and the first cavity 310 are fluidly connected with each other. Further, the precut sheet 125 is arranged between the second cavity 320 and the third cavity 330 in the hollow space 210' defined by the male mould 220 and the female mould 210. The precut sheet 125 forms a fluid barrier between the first cavity 310 and the second cavity 320. The fourth cavity 340 extends along the top 213 of the female mould 210, and is in fluid connection with the second cavity 320. The second cavity 320 has a depth D, measured from the wall 221 of the male mould to the bottom 321 of the second cavity 320. It is clear from fig. lb that the depth D of the second cavity 320 is greater than the depth d of the first cavity 310.

[0051] With reference to fig. lc, the method for forming a shoulder 110 on a container is shown in a step where a liquid polymer 230 has been injected into the first cavity 310. The liquid polymer 230 is injected into the first cavity 310 from a bottom 211 of the female mould 210, in the direction of the arrow shown in fig. lc. The liquid polymer 230 flows through the first cavity 310 until it reaches the second cavity 320. The liquid polymer 230 fills the second cavity 320, whereby a pressure is built up in the second cavity 320. The precut sheet 125 is made from a fiber-based material that may be weaker than the liquid polymer 230. Therefore, when a liquid polymer 230 inside the second cavity 320 has reached a pressure exceeding a pressure threshold of the precut sheet 125, the precut sheet 125 may no longer withstand the pressure acting on it from the liquid polymer 230 in the second cavity 320, and thus the precut sheet 125 may start to deform. Since the precut sheet 125 is arranged between the second cavity 320 and the third cavity 330, the precut sheet 125 in the position of the second cavity 320 has a hollow space on the opposite side of the second cavity 320, the hollow space being the third cavity 330. When the precut sheet 125 is deformed by the liquid polymer 230 in the second cavity 320, it may be pressed into the third cavity 330 and deform into the shape of the third cavity 330, as seen in fig. lc. The third cavity 330 has a triangular profile, why the precut sheet 125 is deformed into a shoulder 110 extending out from the wall portion 120, with a triangular profile. Further, since the second cavity 320 is in fluid connection with the fourth cavity 340, the liquid polymer 230 will flow from the second cavity 320 into the fourth cavity 340. The fourth cavity 340 extends in a horizontal direction outwards from the centerline A, and forms a flange 140 around the periphery of the container (not shown). The liquid polymer 230 injected between the precut sheet 125 and the male mould 220 forms a frame structure 130 of the container.

[0052] Moreover, the liquid polymer 230 hardens by letting it rest in the female mould 210 and the male mould 220 where it has been injected. After the liquid polymer 230 has hardened and become a solid polymer 230, the container 100 may be removed from the female mould 210 and the male mould 220. Thereby, a shoulder 110 is formed in a container 200 comprising a fiber-based wall portion 120 and a frame structure 130.

[0053] With reference to fig. 2a, a detailed view of a shoulder 110 and a top portion 102 in a container 100 according to an exemplifying embodiment of the present disclosure is shown. The container 100 is mirrored on the right side of the centerline A. The detailed view of the container 100 is shown in a state where it has been removed from the male mould and the female mould (not shown). The shoulder 110 protrudes outwards from the wall portion 120, away from the centerline A, and thus away from the inside of the container 100. The container 100 may for example have a circular horizontal cross-section, and in that case the shoulder 110 protrudes outwards from the wall portion 120 in a radial direction. The shoulder 110 has a triangular profile with a first side 110c and a second side llOd. The first side 110c is parallel with the vertical centerline A, extending from a bottom of the container (not shown) to the top portion 102 of the container 100. The second side llOd protrudes from the wall portion 120 with an angle |3 relative the wall portion 120. The angle |3 may be in a range between 0 and 90 degrees. The length of the second side llOd and the size of the angle |3, determines the size of the shoulder 110. The shoulder 110 is a separate part, separated from the top portion 102 of the container 100. Further, the top portion 102 of the container 100 comprises a flange 140. The flange protrudes outwards from the wall portion 120, away from the centerline A. The flange 140 and the shoulder 110 forms part of the frame structure 130. The frame structure 130 is formed by the liquid polymer 230 when it hardens and becomes a solid polymer.

[0054] With reference to fig. 2b, a detailed view of a base portion 101 in a container

[0055] 100 according to an exemplifying embodiment of the present disclosure is shown. The base portion 101 comprises the injecting aperture (not shown) for the liquid polymer 230. Further, a portion 125' of the precut sheet 125 is arranged in the base portion 101 of the container 100. The edges 125'a and 125a between the precut sheet 125 in the wall portion 120 and the precut sheet 125 in the base portion 101 are sealed with the liquid polymer 230. Since the liquid polymer 230 in its hardened state forms the frame structure 130, the frame structure 130 seals the base portion

[0056] 101 of the container 100.

[0057] With reference to fig. 3, a container 100 according to an exemplifying embodiment of the present disclosure is shown. The container 100 has the shape of a truncated cone. The container 100 comprises a circular base portion 101 with a diameter dl, and a circular top portion 102 with a diameter d2. The diameter d2 of the top portion 102 is greater than the diameter dl of the base portion 101. A wall portion 120 extends from the base portion 101 to the top portion 102. The base portion 101 and the top portion 102 are arranged in parallel horizontal planes along the vertical axis A. The wall portion 120 has a slanted profile relative the vertical axis A. Thus, the wall portion 120 extends from the base portion 101 with an angle a. The angle a may be in a range between 0 and 30 degrees. The slanted profile of the wall portion 120 facilitates removal of the container 100 from the female mould 210. The container 100 may be a container for holding a liquid, such as yoghurt, sour cream, or any other edible liquid. The container 100 may further be a container for holding a solid product, such as a type of food product.

[0058] With reference to fig. 4, a precut sheet 125 of a fiber-based material according to an exemplifying embodiment of the present disclosure is shown. The precut sheet 125 is shown in an unfolded state, i.e. before it is inserted into the female mould 210. The precut sheet 125 comprises a first portion 126, a second portion 127 and a third portion 125'. The third portion 125' is inserted in the bottom 211 of the female mould 210, and forms the base portion 101 of the container 100 together with the frame structure 130. The first portion 126 forms one part of the wall portion 120 of the container, and the second portion 127 forms a second part of the wall portion 120. In the example where the container 100 has the shape of a truncated cone, the first 126 and second 127 portions may be bent when inserted into the female mould 210 such that the first 126 and second 127 portions are formed into a truncated cone. The edges 126a, 126b of the first portion 126, meets the edges 127a, 127b of the second portion 127 when the precut sheet 125 is inserted into the female mould 210. The edge 126a of the first portion 126 may meet the edge 127a of the second portion 127, and the similarly the edges 126b and 127b may meet.

[0059] With reference to figs. 5a-5b, a shoulder 110 arranged on a container 100 according to an exemplifying embodiment of the present disclosure is shown. In fig. 5a, the shoulder 110 is arranged continuously around the periphery of the wall portion 120. The shoulder 110 is arranged in a plane parallel to the top portion 102 and the base portion 101 of the container 100, for example the horizontal plane. The shoulder 110 is arranged on the wall portion 120 along the vertical axis A. The shoulder 110 is arranged closer to the top portion 102 than the base portion 101 along axis A. With reference to fig. 5b, the shoulder 110 is comprised by a plurality of shoulder portions 111, 112, 113, 114, 155 distributed around the periphery of the wall portion 120. The shoulder portions 111, 112, 113, 114, 115 are arranged in a plane parallel to the top portion 102 and the base portion 101 of the container 100, for example the horizontal plane. The shoulder portions 111, 112, 113, 114, 115 are arranged on the wall portion 120 along the vertical axis A. The shoulder portions 111, 112, 113, 114, 115 are arranged closer to the top portion 102 than the base portion 101 along axis A. The shoulder portions 111, 112, 113, 114, 115 may each have a triangular profile.

[0060] With reference to fig. 6, a frame structure 130 of a container 100 according to an exemplifying embodiment of the present disclosure is shown. As previously discussed, the frame structure 130 comprises a frame base portion 131, arranged in to base portion 101 of the container 100. The frame base portion 131 provides stability to the base portion 101 of the container 100. The frame structure 130 further comprises a frame top portion 132, arranged in the top portion 102 of the container 100. The frame top portion 132 includes the flange 140. The flange 140 extends outwards from the wall portion 120, which is seen in fig. 6. The flange 110 may be included as being a part of the frame structure 130. The flange 110 seen in fig.6 is continuouslt arranged around the periphery of the wall portion 120. The frame structure comprises at least one leg 133 extending from the frame base portion 131, to the frame top portion 132. In one example, the frame top portion 132 and the shoulder 110 may be formed by the same part. For example, if the container 100 is formed in a smaller size, the shoulder 110 may be arranged in the top portion 102 of the container 100, and therefore the shoulder 110 may form a shoulder and a frame top portion 132. However, as depicted in Fig. 6, the shoulder 110 is a separate part, separated from the top portion 102. The shoulder 110 is arranged in the wall portion 120 along the vertical axis A of the container. The shoulder 110 is arranged closer to the top portion 102 than to the base portion 101, however, there is a distance h (see Fig. 7) between the shoulder 110 and the top portion 102, along axis A. The at least one leg 133 is two legs in the present embodiment. However, only one leg 133 may be seen in fig. 6, the other leg is arranged on the opposite side of the centerline A. The leg 133 seals the edges 126a, 127a of the first portion 126 and the second portion 127 of the precut sheet 125. Thus, the frame structure 130 may both provide stability to the fiber-based wall portion 120 of the container 100, as well as providing a sealing function.

[0061] With reference to fig. 7, a stack 500 of containers 100a, 100b according to an exemplifying embodiment of the present disclosure is shown. A first container 100a is partly arranged inside a second container 100b. The shoulder 110a of the first container 100a abuts and rests against the top portion 102b of the second container 100b. The diameter of the horizontal cross-section at the shoulder 110a exceeds the diameter of the horizontal cross-section at the top portion 102b, why the shoulder 110a rests against the top portion 102b and prevents the first container 100a to be fully inserted into the second container 100b. The shoulder 110a thus forms a spacer between the top portions 102a, 102b between the first container 100a and the second container 100b. The distance h between the top portions 102a, 102b depends on the placement of the shoulder 110a, 110b along the wall portion 120 of a container 100. If the shoulder 110 is arranged closer to the base portion 101 of a container 100, the distance h will increase. Similarly, if the shoulder 110 is arranged closer to the top portion 102 of a container, the distance h will decrease. The distance h between the first container 100a and the second container 100b is beneficial since it allows for a tool (not shown) or a user to grip around the flange 140a, to facilitate separation of the containers 100a, 100b in the stack 500. Further, as seen from fig. 7, there is a gap formed between the wall portion 120a of the first container 100a, and the wall portion 120b of the second container 100b. This means that an air pocket may be formed between the containers 100a, 100b in the stack 500, preventing the wall portions 120a, 120b to abut each other, pressing the air out. Therefore, the containers 100a, 100b may not get stuck inside each other when a plurality of containers are stacked on top of each other, even when the stacking load increases. In the embodiment shown in fig. 7, two containers 100a, 100b are stacked on top of each other. However, there is no limit to the number of containers that may be stacked.

[0062] With reference to fig. 8, a method 400 for forming a shoulder 110 on a container 100 according to an exemplifying embodiment of the present disclosure is shown. The method 400 comprises the step SI of inserting a precut sheet 125 of fiber-based material into a female mould 210 to form the wall portion 120, the female mould 210 having a shape corresponding to the intended shape of the container 100. The method 400 further comprises the step S2 of inserting a corresponding male mould 220 into the female mould 210, the precut sheet 125 being sandwiched between the female 210 and male mould 220. The method 400 further comprises the step S3 of injecting a liquid polymer 230 into a first cavity 310 formed between the precut sheet 125 and the male mould 220 or the female mould 210, to form the frame structure 130. The method further comprises the step S4 of injecting liquid polymer 230 into a second cavity 320 formed in the male mould 220, said second cavity 320 is arranged in a position corresponding to the position of the shoulder 110 on the container. Thereafter the method comprises the step S5 of forcing the precut sheet 125 of fiber-based material to deform into at least one third cavity 330 arranged in the female mould 210 in a position corresponding to desired position of the shoulder 110 such that the shoulder 110 is formed in the wall portion 120, extending outwards from the fiber-based wall portion 120. The method 400 further comprises the step S6 of injecting liquid polymer 230 into a fourth cavity 340 between the male mould 210 and the female mould 220, to form a flange 140 around a periphery of the top portion 102.

[0063] Although features and elements are described above in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements.

[0064] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the figures, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage.

Claims

Claims1. A method (400) for forming a shoulder (110) on a container (100) comprising a fiber-based wall portion (120) and a frame structure (130), the method comprising the steps of: inserting (SI) a precut sheet (125) of fiber- based material into a female mould (210) to form the wall portion (120), the female mould (210) having a shape corresponding to the intended shape of the container (100); inserting (S2) a corresponding male mould (220) into the female mould (210), the precut sheet (125) being sandwiched between the female (210) and male mould (220); injecting (S3) a liquid polymer (230) into a first cavity (310) formed between the precut sheet (125) and the male mould (220) or the female mould (210), to form the frame structure (130); injecting (S4) liquid polymer (230) into a second cavity (320) formed in the male mould (220), said second cavity (320) is arranged in a position corresponding to the position of the shoulder (110) on the container; thereby forcing (S5) the precut sheet (125) of fiber-based material to deform into at least one third cavity (330) arranged in the female mould (210) in a position corresponding to desired position of the shoulder (110) such that the shoulder (110) is formed in the wall portion (120), extending outwards from the fiber-based wall portion (120).

2. Method (400) according to claim 1, wherein the container (100) comprises a base portion (101) and a top portion (102), said top portion (102) comprising an open end, and wherein the wall portion (120) extends from the base portion (101) to the top portion (102).

3. Method (400) according to claim 2, wherein the liquid polymer (230) is injected into the first cavity (310) through the base portion (101) of the container (100).

4. Method (400) according to claim 3, wherein the frame structure (130) comprises a frame base portion (131) and a frame top portion (132) corresponding to the shape of the base portion (101) and the top portion (102) of the container(100), and at least one leg (133) extending from the frame base portion (131) to the frame top portion (132).

5. Method (400) according to claim any one of the preceding claims, wherein a size of the top portion (101) is larger than a size of the base portion (102), and wherein the wall portion (120) extends from the base portion (101) at an angle (a), said angle (a) being relative a vertical axis (A) extending between the base portion(101) and the top portion (102).

6. Method (400) according to claim 5, wherein the shoulder (110) has a triangular profile relative the wall portion (120), and wherein at least one of the sides of the triangular profile is parallel with the vertical axis (A).

7. Method (400) according to any one of the preceding claims, wherein the first cavity (310) has a depth d, the depth d being in a range of 0.1 mm to 5 mm.

8. Method (400) according to claim 7, wherein the second cavity (320) has a depth D, the depth D being greater than the depth d of the first cavity (310).

9. Method (400) according to any one of the preceding claims, wherein the base portion (101) comprises a circular shape having a first diameter (dl), and the top portion (102) comprises a circular shape having a second diameter (d2).

10. Method (400) according to any one of the preceding claims, wherein the shoulder (110) is continuously arranged around a periphery of the wall portion (120).

11. Method (400) according to any one of claims 1 to 9, wherein the at least one third cavity (330) is a plurality of cavities, and the shoulder (110) comprises aplurality of shoulder portions (111, 112, 113, 114, 115) extending outwards from the fiber-based wall portion (120).

12. Method (400) according to claim 11, wherein the plurality of shoulder portions (111, 112, 113, 114, 115) are distributed around a periphery of the wall portion (120).

13. Method (400) according to any one of claims 2 to 12, further comprising the step of: injecting (S6) liquid polymer (230) into a fourth cavity (340) between the male mould (220) and the female mould (210), to form a flange (140) around a periphery of the top portion (102).

14. A container (100) formed by the method (400) according to any of claims 1 to 13, comprising a base portion (101) and a top portion (102), and a wall portion (120) made from a fiber-based material and extending from said base portion (101) to the top portion (102); a frame structure (130) extending from the base portion (101) to the top portion (102) and supporting said wall portion (120); wherein the wall portion (120) is configured to enclose said frame structure (130); and a shoulder (110) arranged in the wall portion (120), extending outwards from the wall portion (120).

15. Container (100) according to claim 14, wherein a first container (100a) may be partly arranged in the top portion (102b) of a second container (100b), forming a stack (500), and wherein the shoulder (110a) of the first container (100a) abuts the top portion (102b) of the second container (100b), forming a spacer (h) between the first container (100a) and the second container (100b) in the stack (500).

Images