WO2014030047A1

WO2014030047A1 - Method for forming the rim of a package, package and moulding tool

Info

Publication number: WO2014030047A1
Application number: PCT/IB2013/001796
Authority: WO
Inventors: Timo Myllys; Pertti SAVIAINEN; Olavi Pirttiniemi; Päivi MÄÄTTÄ
Original assignee: Stora Enso Oyj
Priority date: 2012-08-22
Filing date: 2013-08-20
Publication date: 2014-02-27
Also published as: SE1200506A1

Abstract

A method of forming a package (1), comprising the steps of: shaping a cardboard blank (10) into a container having a bottom (13) and one or more sidewalls (15,30) extending upwardly from the bottom(13), providing a moulding cavity (32) into which an upper edge (18,38) of the one or more sidewalls (15,30) extends, the moulding cavity extending essentially upright from the sidewall (15,30) having its upper edge (18,38) extending into the cavity (32), moulding a rim (16) by injecting a material into the cavity (32), the rim (16) being attached to the one or more cardboard sidewalls (15,30), along an interface (I) formed of an upper portion of the one or more cardboard sidewalls (15,30) and a lower portion of the moulded rim (16), the material being injected with an injection point (P2) being located on an inside of the cardboard blank, the injection point being located adjacent to the upper edge (18,38) of the one or more cardboard sidewalls (15,30).

Description

METHOD FOR FORMING THE RIM OF A PACKAGE. PACKAGE AND

MOULDING TOOL

Technical field of the invention

The present invention relates to the field of packages and more specifically to the field of packages having a moulded rim. Background of the invention

A package having a moulded rim is e.g. disclosed in

WO2009/074721 A1. The package is provided with a bottom and sidewalls extending upwards from the bottom. At the end stage of compression moulding, a rim of moulding material extending sideways is moulded to the upper part of the sidewalls when the mould is kept closed in such a way that a mould cavity corresponding to the rim is formed by moving a counter surface inside the mould backwards from a surface opposite to it, after which the moulding material is introduced into the mould cavity. This provides the package with a horizontally extending flange which may be used to glue or heat seal a plastic or paper lid onto the upper surface of the horizontally extending flange.

The above mentioned WO2009/074721A1 was amongst others developed to take into account that sometimes there is a need to provide the edge flange with a material that is suitable for fixing the lid but is not necessarily required in the middle part, that is, inside the package, or that is even unsuitable as a material inside the package.

However, in some cases, the edge flange material has a higher carbon footprint than the board material. Low carbon footprint is nowadays an important factor when brand owners are selecting packages for a new product or replacing existing packages.

Summary of the invention

In view of the above, an objective of the present invention is to provide a package leaving as low carbon footprint as possible and a method for manufacturing such a package.

Moreover, another objective of the present invention is to provide a package having a low production cost and a method for manufacturing such a package. A further objective of the present invention is to provide a moulding tool for use in forming such a package as described above.

According to a first aspect, the present invention is realized by a method of forming a package, comprising the steps of: shaping a cardboard blank into a container having a bottom and one or more sidewalls extending upwardly from the bottom, providing a moulding cavity into which an upper edge of the one or more sidewalls extends, the moulding cavity extending essentially upright from the sidewall having its upper edge extending into the cavity, moulding a rim by injecting a plastic material into the cavity, the rim being attached to the one or more cardboard sidewalls, along an interface formed of an upper portion of the one or more cardboard sidewalls and a lower portion of the moulded rim, the plastic material being injected with an injection point being located on an inside of the cardboard blank, the injection point being located adjacent the upper edge of the one or more cardboard sidewalls.

The present invention may make it possible to produce a package where the volume of the rim of the package is reduced. Due to the positioning of the injection point, both the height of the vertical part of the rim and the width of any horizontal part of the rim may be reduced. By reducing the volume of the rim, a more cost efficient package may be achieved. Often, the plastic material has a higher carbon footprint than the board material, thus it is beneficial to reduce the amount of plastic material in a package since less plastic is used and thereby less nature resources, e.g. oil, is consumed.

A plastic rim enables tight sealing of the lid and thus makes it possible to use trays as MAP, modified atmosphere packaging, packages. A plastic rim may provide a good seal between the cardboard edge and the stuff in the package. This is often advantageous since any moisture in the package, e.g. from food-stuff or the like, have a tendency to enter into the cardboard edge and soak the cardboard such that the cardboard loses its mechanical strength and looks less aesthetic. A further advantage of using a plastic material may be that the rim will be rigid enough to be used as a ridge or peak for a snap- lock on the cover. The plastic material may be both thermoplastic and/or thermosetting plastic.

Moreover, the rigidity of the rim of a package produced by this method may still be sufficient for withstanding forces acting upwardly or downwardly, thus making it easy to heat-seal or otherwise connect a cover to the upper surface of the rim. A further advantage of this method may be that the plastic material is injected against the board edge in such a way that the injection force presses the edge of the board against the mould wall, thereby reducing the risk of getting the material on the wrong side of the board. This may also make it possible to use injection moulding where the injection point connects to a side surface of the rim. This in turn makes it possible to make the moulding tool design more compact.

By positioning the injection point on the inside of the cardboard blank, the injection point will not interfere with any horizontal part of the rim to be used as a part of a sealing, separately or integrally as a member of a snap- lock. Moreover, the injection point will be hidden on the inside of a package produced by the method of the present invention. This may lead to a more aesthetic design of the package.

The injection point may be positioned 1-2 millimetres below the upper edge of the one or more cardboard sidewalls. The positioning accuracy when shaping the cardboard blank is ~1 mm so to be on safe side the injection point needs to be at least ~1 mm below the planned edge. Rim profile dictates the max distance to the board edge but typically it could be 2 mm. In further embodiment the injection point may be placed more than 2 mm below the board edge.

The injection point may be positioned 0.3-2 millimetres from the cardboard sidewalk The preferred distance is ~1 mm. The rim profile defines the injection point. The thickness of the plastic at the injection point depends on the tray shape. The deeper the tray or the sharper the corners the more board needs to be wrinkled. The more board is wrinkled the more uneven the upper edge of the wall is and the more plastic is needed to cover the board.

According to another embodiment of the present invention, the injection point of the step of moulding the rim comprises multiple injections points along a perimeter near the upper edge of the one or more cardboard sidewalls. This may make the production of a package more time efficient since the moulding cavity is filled with the injection material more quickly. Using a multiple of injection points may also ensure that the injected material is evenly distributed in the moulding cavity.

According to yet another embodiment of the present invention, the step of shaping the cardboard blank comprises shaping the upper portion of the one or more cardboard sidewalls to which the moulded rim will be attached such that it forms a continuous straight line. Since the rim material is injected against the board edge in such a way that the injection force presses the edge of the board against the mould wall, no bend of the board edge is necessary for ensuring that the board edge is pressed against the mould wall. This may simplify the production of the package since no extra production step needs to be added for creating such a bend of the cardboard sidewalls. A further advantage may be that a more aesthetic design of the package is possible.

According to an embodiment of the present invention, the step of moulding the rim comprises injecting the material into the cavity via side gated hot runner nozzles.

By the term "side gated hot runner nozzles" should, in the context of present specification, be understood that the nozzle tip is in an angle compared to the nozzle body. This makes it possible to inject the rim material into a vertical surface. A further advantage may be that a more compact design of the moulding tool is possible since the nozzle body may be vertically positioned in the moulding tool.

In a second aspect, the present invention provides a package comprising a cardboard blank, the cardboard blank being shaped as a container with a bottom and one or more cardboard sidewalls extending upwardly from the bottom, the package further comprising a moulded rim being attached to the one or more cardboard sidewalls, along an interface formed of a continuous straight upper portion of the one or more cardboard sidewalls and a lower portion of the moulded rim.

This may simplify the production of the package since no extra production step needs to be added for!creating such a bend of the cardboard sidewalls. Another advantage is that if the bend is left away the board and its plastic coating is not stressed and the probability of pin holes is reduced. A further advantage may be that a more aesthetic design of the package is possible. Yet another advantage may be that the volume of the rim is reduced, thereby allowing a more cost efficient package. Often, the rim material, e.g. a plastic material, has a higher carbon footprint than the board material, thus it is beneficial to reduce the amount of rim material in a package since less plastic is used and thereby less nature resources, e.g. oil, is consumed. The rim material may be both thermoplastic and/or

thermosetting plastic.

According to an embodiment of the present invention, the interface of a continuous straight upper portion of the one or more cardboard sidewalls and a lower portion of the moulded rim may be between 2-3 millimetres long. This interval provides a good balance between the strength of the rim and the material cost and carbon footprint of the rim.

According to another embodiment of the present invention, at least a part of the one or more cardboard sidewalls just beneath the upper portion forms a continuous straight line with the connected upper portion. An advantage may be that a more aesthetic design of the package is possible.

The rim may be provided with a horizontal part extending outwardly from an outside of the rim and extending along at least a part of the rim in a circumferential direction. This way the horizontal part may act as a member in a snap-lock keeping the cover or lid securely in place on the package. The horizontal part may be divided into several portions each only extending along a portion of the circumferential direction of the rim. The horizontal part may also be continuous and extend a complete lap around the mouth of the package. Such a horizontal part may be used as a part of a sealing, separately or integrally as a member of a snap-lock.

According to an embodiment, the distance between the horizontal part of the rim and the upper edge of the one or more cardboard sidewalls is between 0.8 - 3 millimetres. The positioning accuracy when shaping the cardboard blank is -1 mm so to be on safe side when injection moulding the rim, a small distance between the horizontal rim and the upper edge of the one or more cardboard sidewalls is needed.

According to yet another embodiment, the horizontal part is between 0.4 - 4 millimetres. An advantage of having a horizontal part of the rim narrower than ~4 mm may be that a permanent mould cavity may be used in the moulding tool that forms the package without disturbing the forming process. This removes the need of having a collar ring for forming the mould cavity when the forming process is complete, thus a more cost efficient moulding tool is possible and consequently a cheaper package may be produced.

In another embodiment of the present invention, the rim is formed by injection moulding onto the cardboard blank with an injection point being located on an inside of the cardboard blank, the injection point being located near the upper edge of the one or more cardboard sidewalls.

Due to the positioning of the injection point, both the height of the vertical part of the rim and the width of any horizontal part of the rim may be reduced. By reducing the volume of the rim, a more cost efficient package may be achieved. Often, the plastic material has a higher carbon footprint than the board material, thus it is beneficial to reduce the amount of plastic material in a package since less plastic is used and thereby less nature resources, e.g. oil, is consumed.

The injection point may comprise multiple injections points along a perimeter near the upper edge of the one or more cardboard sidewalls. Using a multiple of injection points may ensure that the injected material is evenly distributed in the rim.

In a third aspect, the present invention provides a moulding tool for use in forming a package, the moulding tool comprising a first mould body and a second mould body, the first mould body being essentially bowl shaped and the second mould body being formed as a protrusion essentially conforming with the first mould body, the first and second mould bodies being adapted to together form a cavity for receiving and shaping a cardboard blank into a container having a bottom and one or more cardboard sidewalls extending upwardly from the bottom, the cavity being shaped such that they between them provides a widened cavity portion into which an upper edge of the cardboard sidewalls is adapted to extend, the widened moulding cavity portion having its upper edge extending into the cavity portion, the widened cavity portion being connected to a hot runner nozzle whereby a rim can be moulded onto the one or more cardboard sidewall by injecting a plastic material into the widened portion of the cavity, the plastic material being injected with an injection point being located on an inside of the cardboard blank, the injection point being located adjacent the upper edge of the one or more cardboard sidewalls.

The third aspect may generally have the same features and

advantages as the first and second aspect.

Other objectives, features and advantages of the present invention will appear from the following detailed disclosure and from the drawings.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [element, device, component, means, step, etc]" are to be interpreted openly as referring to at least one instance of the element, device, component, means, step, etc., unless explicitly stated otherwise.

The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. Brief description of drawings

The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:

Figs 1 -2 shows a package according to an embodiment.

Fig 3 is a schematic drawing illustrating a conventional injection point.

Fig 4 is a schematic drawing illustrating an injection point according to embodiments.

Fig 5 is a schematic drawing illustrating a part of a moulding tool according to embodiments during the process of forming a board blank to a package.

Fig. 6 is a schematic drawing illustrating a side gated hot runner nozzle according to embodiments

Fig. 7 is a schematic drawing illustrating a part of a moulding tool according to embodiments.

Fig. 8 is a schematic drawing illustrating a moulding tool according to embodiments. The moulding tool is in its opened position.

Fig 9 shows the moulding tool of fig 8 in its closed position.

Fig 10 show the moulding tool of fig 8 and 9 a position where an ejector plate has removed a moulded package from the second mould half.

Detailed description of the invention

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This 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.

An object of the present invention is to reduce the volume of a plastic part, e.g. a rim, of a package. Since a rim material often has a higher carbon footprint than a board material, this is advantageously from an environmental point of view. A package with a smaller rim volume reduces the need of plastics which means that less natural resources, e.g. oil, is consumed. This gives a better carbon footprint of a package of the present invention. This may also mean that the package gets a more competitive price.

The rim may be formed by injection moulding onto a cardboard blank with an injection point being located on an inside of the rim. By using injection moulding it is possible to shape relatively complicated shapes. It is also possible to use the injection moulding of the plastic material to securely attach the rim to the cardboard blank. By providing the injection point, the point where the plastic material is introduced into a mould cavity, on an inside of the rim, it is possible to provide a injection nozzle in a part of a moulding tool not provided with a number of other functionalities. This facilitates the design of the moulding tool. The number of injection points may vary depending on the requirements. In some embodiments there is just one injection point but in other embodiments there is multiple injection points distributed evenly along the perimeter of the cardboard edge.

Figs 1 and 2 discloses a rectangular package 1 having a rectangular bottom 13 and four sidewalls 15 integrally formed with the bottom 13 and extending upwardly from the bottom 13. As is shown in figs l and 2, the four sidewalls 15 are in fact formed as a single continuous sidewall 5 with curved corner portions and straight portions between the corners. A similarly shaped rectangular package may also be provided using a folding operation at the corners. The sidewalls 15 are provided with a rim 16. A horizontal part 12 of a rim 6 of the package 1 is 4 millimetres but according to embodiments of the present invention, the width can be as narrow as 0.5 millimetres since the space required for the injection gate does not put any requirements on the dimensions of the horizontal part 12 of the rim 16 as will be described below. Compare with having the injection position at the corner of the rim. This would require the width of the rim to be at least 7 mm to have enough space in the corners for a hot runner nozzle and the injection gates to fit. In some embodiments of the present invention, a space 14 between the horizontal part 12 of the rim 16 and an end portion 18 of a cardboard blank 10 only need to be about 1 millimetre as will be described below.

As can be seen in Fig 4, an injection point P2 is located on the inside of the cardboard sidewall 30. A hot runner nozzle is used to inject the plastic material into a plastic cavity 32. The plastic material is lead through the injection gates and into the hot runner where it is injected via the hot runner nozzle. Since the hot runner nozzle is positioned on the inside of the package, adjacent to the injection point P2, the space required for the injection gate does not put any requirements on the dimensions of the rim i.e. the rim may be designed based on the demands on the package as such. Naturally, the injection gates still needs to fit to the rim, but this is usually not a problem since the total height of the rim is enough, Compare with if the hot runner nozzle was positioned on the outside of the package, as can be seen in Fig 3, with an injection point P1 between an sidewall upper edge 38 of the cardboard sidewall 30 and a horizontal part 34 of the plastic cavity 32. This requires that a vertical part 36 between the cardboard sidewall upper edge 38 and the horizontal part 34 of the plastic cavity 32 is at least 4 mm since this is the space taken up by the injection gates. According to embodiments of the present invention, as visualised in Fig 4, the vertical part 36 between the horizontal part 34 of the plastic cavity 32 and the upper edge 38 of the cardboard 30 only need to be about 1 millimetre high to overcome blank position inaccuracy when shaping the cardboard blank into a container.

Figs. 3-4 also discloses how different positioned injection points put different requirements of the end part of the board. In Fig 3, the injection point P1 is positioned on an outside of the package. To make sure that the injected material gets on the correct side of the cardboard sidewall 30, e.g. on the inside, the end part of the cardboard sidewall 30 must be bended such that bending stress of the end part of the cardboard sidewall 30 presses the upper edge 38 towards the mould wall, as visualized by the arrow in Fig 3. In Fig 4, the injection position P2 according to an embodiment of the present invention is disclosed. According to the present embodiment, the injected material is injected near the upper edge 38 of the cardboard sidewall 30, leading to that the injection force presses the cardboard sidewall edge 38 towards the mould wall. This in turn leads to that no part of the injected material ends up on the wrong side, e.g. the outside, of the board. Consequently there is no need of having a bent or curved end part of the cardboard sidewall 30. This may simplify the shaping of the cardboard blank into a container. A further advantage is that less plastic may be needed for the lower part of the rim, as clearly visible when comparing Fig. 3 and Fig. 4. The injection point P2 may be positioned 1-2 millimetres below the upper edge 38 of the cardboard sidewall 30. The distance to the cardboard edge 38 is amongst others determined by the desired rim profile and the positioning accuracy when shaping the cardboard blank.

Fig. 5 shows a schematic cross-sectional view of a forming and moulding tool 50 for forming a package during the process of forming a cardboard blank 58 to a package. The package is formed by moving a core 56 towards a cavity plate 54. While forming the package, the cardboard blank 58 is pressured on one hand by a ejector plate 52 and the cavity plate 54, e.g. to the left of the plastic cavity 32 in Fig. 5, and on the other hand by the core 56 and the cavity plate 54, e.g. below the plastic cavity 32 in Fig. 5. The dimensions of the plastic cavity 32 depend on the desired dimensions of the rim of the package. In some embodiments of the present invention, during forming of the package the cardboard blank 58 travels over the plastic cavity 32 and if the cavity 32 is too wide the forming process is disturbed. This leaves the top of the cardboard blank 58 edge uneven since it is not completely pressed during forming nor in the board cavity since the edge of the cardboard blank 58 is positioned in the plastic cavity 32 when the forming is finished such that no pressure is applied to the board edge. In other words, the wider the cavity for plastic 32 is, the longer part of the top edge of the cardboard blank 58 is formed without hold pressure, e.g. from the ejector plate 52 and the cavity plate 54, e.g. to the left of the plastic cavity 32 in Fig. 5. Without hold pressure the crease formation may be disadvantageous and the top edge of the cardboard blank 58 may become uneven. This may cause the plastic/board interface I to not fill perfectly and this may lead to that the package is not gas tight. In the case that the desired rim is 4 millimetres wide or less, this poses no problem. If the desired rim is wider than 4 millimetres, a static plastic cavity, e.g. the plastic cavity 32 in Fig. 5, is not an option and instead a collar ring is necessary. The collar ring applies pressure to the blank during the forming process and is later moved to form a plastic cavity. The width of the rim of a package of the present invention can be as narrow as 0.5 millimetres as described above. Consequently, in some embodiments of the present invention, the need of a collar ring is removed which in turn facilitates the design of the moulding tool 50 and leads to a cheaper moulding tool 50 and a more simple moulding process.

Fig. 6 shows a side gated hot runner nozzle that may be used for forming the package of the present invention. A nozzle tip 62 is in an angle compared to a nozzle body 64. This makes it possible to inject into vertical surfaces, e.g. the cardboard sidewall 30. The angle between the nozzle tip 62 and the nozzle body 64 depends on the type of nozzle used. Since the nozzle body 64 may be vertical positioned in the moulding tool, it is possible to provide the nozzle in a part of the moulding tool not provided with a number of other functionalities. This facilitates the design of the moulding tool. Fig 7 is a schematic drawing illustrating a part of the forming and moulding tool 50 according to embodiments of the present invention. The cardboard blank has been shaped into a container by the core 56 and the cavity plate 54. The cardboard sidewall 30 may be between 0.25-0.8 mm thick. The moulding cavity 32 consists of a vertical part 73 and the horizontal part 34. The vertical part 73 may be between 3.6-5 mm high and the horizontal part 34 may be between 0.5 mm and 3.5 mm wide. The horizontal part may include a protruding part 74 which width may be between 0-3.0 mm. A height 76 of the protruding part 74 may be between 0-0.8 mm. The interface I between the cardboard blank 30 and the moulding cavity 32 may be between 1-4 mm high and the vertical part 36 of the cavity 32 positioned between the end of the cardboard sidewall 30 and the horizontal part of the cavity 32 may be typically be 1 mm, but will vary in practice between 0-2 mm high as explained above.

Figs. 8-10 show cross-sectional views of the forming and moulding tool

50 for forming the package 1. Basically the moulding tool comprises a first mould half or body 80 and a second mould half or body 90. The first mould body 80 is provided with two bowl shaped recesses 83a, 83b. The second mould body 90 is provided with two protruding members 101a and 101 b as best seen in Fig. 10. When brought together, a top portion of the protruding members 101a and 101 b form together with the recesses 83a and 83b two cavities in which the cardboard blank 10 is adapted to be shaped into a container and to be provided with a rim 16 and thereby form the package 1.

The first mould half 80 further comprises a clamp plate 81 , an insulating plate 82 and the cavity plate 54. The second mould half further comprises the ejector plate 52, the core 56, a hot runner nozzle 100a, 100b, a back mould plate 91 , a support plate 92, a pneumatic cylinder 93, a clamp plate 94, an insulating plate 95, a sprue 96 for moulding material, a location ring 97, a manifold plate 98 and a hot runner manifold 102.

The package 1 is basically manufactured according to the following.

The flat cardboard blank 10 is brought on top of the first mould half 80 and hold in place by vacuum. As the mould is closed, i.e. the mould halves 80 and 90 are brought closer to each other, the protruding members 101a and 101 b will push the cardboard blank into the recesses 83a and 83b thereby shaping the flat cardboard blank into a container having the bottom 13 and one or more sidewalls 15 extending upwardly from the bottom 13. In the beginning, when the protruding members 101a and 101 b is pushing the cardboard blank into the recesses 83a and 83b, the ejector plate 52 is in its front position, as can be seen in Fig. 8, such that it directs force to the blank during forming, e.g. so that the creases forms correctly. During closing of the mould, the ejector plate is moved back to its final position as can be seen in Fig 9. The force of the mould is directed by the pneumatic cylinders 93.

For a circular or ellipsoid or otherwise similarly shaped container 1 it may be considered common to speak of one sidewall. For a rectangular or otherwise similarly shaped container it may be considered common to speak of more than one sidewall (e.g. four sidewalls in case of a rectangular container and three in case of a triangular container). It should be noted that the plurality of sidewalls are still preferably integrally formed of a single cardboard blank and the junction between the sidewalls are thereby formed as a continuous but sharply bent or folded portion of the cardboard blank. In one sense such a container may also be said to have a single sidewall, with this single sidewall being formed of four comparably straight portions and four curved portions or corner portions.

Fig. 9 illustrates the forming and moulding tool 50 in its closed position. The recesses 83a and 83b and the protruding members 101 a and 101 b are shaped such that when the mould 50 is closed there is a space just sufficiently wide to allow the cardboard blank to be accommodated between them. The level of pressure exerted onto the cardboard will be dependent upon the choice of cardboard material, the choice of shape of the container, etc. Such parameters are well known to a person skilled in the art and will not be described in .any detail.

In the lower most portions of the recesses 83a and 83b, i.e. the portion corresponding to the top portion of the sidewall 15 of the container, the recesses 83a and 83b and the protruding members 101 a and 101 b are designed such that a cavity 32 is formed. The cavity 32 extends completely around the perimeter of the recesses 83a and 83b. The cavity 32 is adapted to be filled with molten plastic using a so-called injection moulding operation. Plastic material which is heated such that it is mouldable is injected under pressure into the cavity 32 and will fill every part of the cavity 32. The plastic material will thereby assume the same shape as defined by the cavity 32. The plastic material is then cooled such that it solidifies in the shape defined by the cavity 32.

The plastic material is injected to the cavity 32 using the hot runner nozzle 100a, 100b. The hot runner nozzle 100a, 100b is located in the second mould body 90 on an inside of the cavity 32. Thus, the hot runner nozzle 100a, 100b connects to the cavity 32 such that as viewed from the package 1 , the plastic material will be injected from an inside of the rim.

Suitable moulding materials include various thermoplastics which are melt processable; in other words, they can be supplied in molten state into the mould cavity, in which they solidify and attach directly to the cardboard or to a plastic coating of the cardboard, forming simultaneously a rigid rim. Suitable polymers, on which these plastics are based, include polyolefins, polyesters and polyamides. Environmentally friendly moulding materials include biodegradable plastics, such as any of the following: polylactide (PLA), biodegradable polyester, starch-based plastics or polyhydroxy alkanoate, particularly PHB. In this way, the recyclability of the package can be improved as a whole, even though it has been made partly by injection moulding. The above-mentioned biodegradable plastics may also be used as materials for coating the cardboard blank.

In Fig 10, the final step of the manufacturing process of the package 1 is visualized. The ejector plate 52 is moved to the front position. In this movement, the ejector plate 52 removes the finished package 1 comprising the rim 16 from the protruding members 01a and 101 b. The package 1 is now free to be removed by a robot or the like.

The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the packages of the present invention may be provided with hooks/openings or hinge systems on the rim. These additional features may require additional moving parts in the forming and moulding tool.

Claims

1 . A method of forming a package (1 ), comprising the steps of:

shaping a cardboard blank (10) into a container having a bottom (13) and one or more sidewalls (15,30) extending upwardly from the bottom(13), providing a moulding cavity (32) into which an upper edge (18,38) of the one or more sidewalls (15,30) extends, the moulding cavity extending essentially upright from the sidewall (15,30) having its upper edge (18,38) extending into the cavity (32),

moulding a rim (16) by injecting a material into the cavity (32), the rim

(16) being attached to the one or more cardboard sidewalls (15,30), along an interface (I) formed of an upper portion of the one or more cardboard sidewalls (15,30) and a lower portion of the moulded rim (16), the material being injected with an injection point (P2) being located on an inside of the cardboard blank, the injection point being located adjacent the upper edge (18,38) of the one or more cardboard sidewalls (15,30).

2. The method according to claim 1 , wherein the injection point (P2) is positioned 1-2 millimetres below the upper edge (18,38) of the one or more cardboard sidewalls (15,30).

3. The method according to any one of claims 1-2, wherein the injection point (P2) is positioned 0,3-2 millimetres from the one or more cardboard sidewalls (15,30).

4. The method according to any one of claims 1 -3, wherein the injection point (P2) of the step of moulding the rim (16) comprises multiple injections points along an perimeter near the upper edge (18,38) of the one or more cardboard sidewalls (15,30).

5. The method according to any one of claims 1-4, wherein the step of shaping the cardboard blank comprises shaping the upper portion of the one or more cardboard sidewalls (15,30) to which the moulded rim (16) will be attached such that it in a cross section parallel to a normal of the bottom (13) forms a continuous straight line.

6. The method according to any one of claims 1-5, wherein the step of moulding the rim (16) comprises injecting the material into the cavity (32) via a side gated hot runner nozzle (72,74).

7. A package (1) comprising a cardboard blank (10), the cardboard blank (10) being shaped as a container with a bottom (13) and one or more cardboard sidewalls ( 5,30) extending upwardly from the bottom (13), the package (1) further comprising a moulded rim (16) being attached to the one or more cardboard sidewalls (15,30), along an interface (I) formed of a continuous straight upper portion of the one or more cardboard sidewalls (15,30) and a lower portion of the moulded rim (16).

8. The package (1) according to claim 7, wherein the interface (I) is between 1-4 mm long, preferably between 2-3 millimetres long.

9. The package (1) according any one of claims 7-8, wherein at least a part of the one or more cardboard sidewalls(15,30) just beneath the upper portion in a cross section parallel to a normal of the bottom ( 3) forms a continuous straight line with the connected upper portion.

10. The package (1) according to any one of claims 7-9, wherein the rim (16) is provided with a horizontal part (12) extending outwardly from an outside of the rim (16) and extending along at least a part of the rim (16) in a circumferential direction.

1 1. The package (1 ) according to claim 10, wherein the distance between the horizontal part (12) of the rim and the upper edge (18,38) of the one or more cardboard sidewalls (15,30,40) is between 0.8 - 3 millimetres.

12. The package (1 ) according to any one of claims 10-11 , wherein the horizontal part (12) is between 0.4 - 4 millimetres wide.

13. The package (1 ) according to any one of claims 7-12, wherein the rim (16) is formed by injection moulding onto the cardboard blank (10) with an injection point (P2) being located on an inside of the cardboard blank (10), the injection point (P2) being located near the upper edge (18,38) of the one or more cardboard sidewalls (15,30).

14. The package (1) according to any one of claims 7-13, wherein the injection point (P2) comprises multiple injections points along an perimeter near the upper edge (18,38) of the one or more cardboard sidewalls (15,30).

15. A moulding tool for use in forming a package, the moulding tool comprising a first mould body (80) and a second mould body (90), the first mould body (80) being essentially bowl shaped and the second mould body (90) being formed as a protrusion essentially conforming with the first mould body, the first and second mould bodies being adapted to together form a cavity for receiving and shaping a cardboard blank (10) into a container having a bottom (13) and one or more cardboard sidewalls (15, 30) extending upwardly from the bottom (13), the cavity being shaped such that they between them provides a widened cavity portion (32) into which an upper edge of the cardboard sidewalls (15, 30) is adapted to extend, the widened cavity portion (32) being connected to a hot runner nozzle (100a, 100b), whereby a rim (16) can be moulded onto the one or more cardboard sidewall (15, 30) by injecting a plastic material into the widened portion (32) of the cavity via the hot runner nozzle, the plastic material being injected with an injection point (P2) being located on an inside of the cardboard blank, the injection point being located adjacent the upper edge (18,38) of the one or more cardboard sidewalls (15,30).