Field of the invention

The present invention relates to metal cans used as packaging, in particular for powdered products such as infant nutrition or milk formula. The invention further relates to the use of embossing to improve the overall mechanical strength and resistance to dents of such metal cans and their combination with supporting sleeves in a composite can construction.

Background art

Metal cans have been used for the packaging of powdered materials for many years as they may be sealed for long term storage and are relatively easy and cheap to produce. It is beneficial from both an economical and environmental perspective to use as little resources as needed when manufacturing such metal cans.

One way of reducing metal usage is by making the sidewall of the cans thinner. Yet reducing the sidewall thickness affects the strength of the can. A certain mechanical strength of a can is required to prevent damage of the can, for instance to absorb shocks due to rough handling during manufacturing or during transportation or to withstand axial loads that are applied to the can when sealing the product or as a result of stacking. Hence a can’s mechanical strength is a limiting factor in reducing the sidewall thickness and reducing metal usage.

Embossing a can with beads or corrugations over its sidewall in horizontally and vertically extending patterns is known. US Pat. No 4,512,490, describes a can construction provided with primary beads. Also disclosed are protuberances or raised portions forming auxiliary beads and extending essentially at right angles or perpendicular to the primary beads that flow into or continuously merge with the primary beads.

For certain embossing patterns, the radial load strength and impact resistance may be significantly improved by the embossing, whereas a low axial load resistance remains. Consequently, the low axial load resistance may be a limiting factor for a further reduction of the can’s sidewall thickness.

It would be desirable to provide an improved can that allows a saving of metal resources by further reducing the thickness of the sidewall of a metal can, while not affecting the can’s axial load strength and the can’s robustness regarding puncturing and denting upon impact. It would also be desirable to provide an improved metal can that is environment friendly and allows for easy recycling.

Summary of the invention

According to the present invention, there is provided an infant formula package comprising a metal can having a base and a sidewall, wherein the sidewall is provided with embossing. The sidewall has a plurality of embossed two-dimensional (2D) protrusions, protruding from an otherwise essentially planar surface. In this context, the term“embossed 2D protrusions” may be used to refer to any embossed shape that extends both horizontally and vertically along the sidewall surface for a distance significantly exceeding the depth/height of the protrusion. For the avoidance of doubt, the protrusions may extend outwardly and/or inwardly from the surface. The shape of the protrusions may be chosen to achieve optimal strength for the can, be it crush strength, impact strength or load strength. In addition, the embossing may be provided to improve the aesthetics of the package. The package further comprises a re-sealable closure.

In the proposed package, the extent of the embossing may also be chosen to achieve the optimal strength for the can, be it crush strength, impact strength or load strength. In this context, the extent of the embossing is intended to denote the amount of the sidewall over which embossing is present. In certain embodiments, the embossing on the sidewall may be applied over the full periphery of the sidewall. This may particularly be the case for a circular cylindrical can, where the embossing may be distributed evenly around the circumference. In certain embodiments, the embossing on the sidewall may be applied over the full height of the sidewall. Preferably the embossing is applied over at least 30% of the height of the sidewall. In other embodiments, the embossing is applied over at least 70%, or at least 80%, or at least 90% of the height of the sidewall. The total embossed area, namely the area where embossing has been carried out, may be at least 30%, or at least 50%, or at least 70% or at least 85% of the total area of the sidewall.

The degree of embossing may also be chosen to achieve the optimal strength for the can, be it crush strength, impact strength or load strength. In this context, the degree of embossing is intended to denote the area of distorted material as a percentage of the surface, within the embossed area. The embossing may comprise individual, isolated depressions or protrusions that extend from a plane of the sidewall. In the following, reference will be given to protrusions, it being understood that a depression on an inner surface of the sidewall will correspond to a protrusion on an outer surface of the sidewall and vice-versa. Embossing that is directed inwards may sometimes be referred to as debossing. The sidewall may be planar or otherwise undistorted between adjacent protrusions i.e. for a cylindrical can, the sidewall surface may follow the arc of the cylinder for the distance between protrusions. The degree of embossing may be between 5% and 50%, or between 10% and 30% within the embossed area.

In preferred embodiments, the embossing pattern has a non-cellular structure. Here the term‘cellular structure’ is used to indicate embossing patterns wherein the entire sidewall surface is covered by embossed tessellations of triangles, squares, pentagrams, hexagrams, or other shapes, and in addition the inner shape of the cells is embossed, rather than the outer contour of the shape. Consequently, the can sidewall of a can with an embossed cellular structure, for example in Japanese publication 4,728,150 B2, as looked upon from a vertical cross section, consists of sequentially connected arches. No planar surface remains in the embossed region. In a non-cellular structure, the can sidewall, consists of an essentially planar surface from which the protrusions extend. The presence of a planar surface is beneficial for fitting a label or sleeve around the metal can.

Each protrusion may have an area and a depth according to the required result. In an embodiment, each protrusion may have an area between 15 mm ² and 500 mm ² , preferably between 15 mm ² and 125 mm ² . The depth of each protrusion may be between 0.1 mm and 0.5 mm, more preferably between 0.1 mm and 0.36 mm.

The protrusions may be present in any appropriate 2D shape. Shapes may include circles, diamonds, triangles, hearts and other regular or irregular geometric shapes, subject to them extending in two-dimensions along the surface of the sidewall for a distance significantly exceeding the depth/height of the protrusion. In this context, significantly exceeding may be interpreted as having an extent that is at least 5 times or at least 10 times greater than the depth of the protrusion. The surface area of an individual embossed shape in embodiments may have an area between 25 mm ² and 500 mm ² , preferably around 125 mm ² .

In certain embodiments, the protrusions may each be in the form of a design such as a logo. Embossing with protrusions of a particular shape may give additional strength to the sidewall but may also be used for aesthetic purposes.

According to certain embodiments, each protrusion may comprise an elongate isolated contour. The contour may be of constant cross-section. In this context, isolated is intended to denote that one contour may be separated from another contour by a region that is otherwise planar. In other words, that one protrusion does not intersect with an adjacent protrusion. The term contour is used to indicate that the protrusion follows a path in two dimensions i.e. it is not a straight line.

Each contour may be open or closed. A closed contour has both ends meeting to form a closed outer periphery of a shape. For an embossed closed contour the inner area of the shape may be essentially planer with the remained of the sidewall. It is however not excluded that this inner area may be partially embossed too or debossed with respect to the contour. In an embodiment, each contour may have a total length less than 80 mm, preferably between 15 mm and 80 mm, more preferably between 30 mm and 60 mm. In an embodiment the contours may comprise shapes like for instance a company’s logo, circles, stars, or hearts in an arrangement that is both decorative and also increases the mechanical strength of the can. The contours extend a distance at least in an axial direction and in a peripheral direction around the sidewall. In this manner, they may assist in increasing both the axial load strength and the radial impact strength.

In embodiments, the embossing leads to protrusions extending to the inside volume of the can, leading to an outer surface of the sidewall that is essentially planar. By leaving the outer surface of the sidewall essentially planar, a label or sleeve may be more tightly fitted around the metal can. The protrusions of the embossing can alternatively extend outward from the outer surface. By applying the embossing in such a way that the protrusions extend outward from the sidewall, a grip between the metal can and a wrapper or sleeve around the can may be improved. In a further alternative, a mixture of protrusions and depressions may be provided on both the inner and outer surfaces.

The package further comprises a re-sealable closure that allows for reclosing of the package after use and may also be used to close the package before first use. This re-sealable closure is preferably made of plastic material. These materials can very well be recycled to fabricate new products. In certain embodiments, the re-sealable closure may be a lid or cap that is completely removable. After emptying a package entirely, the lid may be removed from the package to be recycled separately or to be put on another full package to continue being used.

In other embodiments, the re-sealable closure may comprise a peripheral rim connected to an upper part of the peripheral wall. The rim defines an aperture. The re-sealable closure further comprises a lid that is hingedly connected to the rim, and allows for selectively closing the aperture. In preferred embodiments, the re-sealable closure further comprises a locking mechanism to prevent the lid from opening. Also re-sealable closures with a fully removable cap or lid may be equipped with such a locking mechanism.

According to further embodiments, the package may comprise a releasable seal for closing the can prior to use. The seal may be connected to an inner surface of the sidewall of the can at a distance below the sidewall top edge and may be at least partially removable to gain access to the inner volume of the can. Alternatively, the seal may be applied across a top edge of the sidewall or across an access opening in a topwall. The seal may be welded, adhered or heat-sealed to the can using any appropriate connection technique.

The seal allows for hermetically closing the can prior to use. The contents of the package, namely the powdered nutritional product, may be packaged under a protected atmosphere. The seal is intended to ensure that the contents are kept under this protected atmosphere until the user breaks the seal. Preferably, the seal comprises an oxygen barrier layer such as a metallic layer or an EVOH layer or equivalent. The seal must be at least partially removed to gain access to the product and may be provided with a tear strip or pull tab or the like. In one embodiment, the seal is attached to the inner sidewall at a small distance below the sidewall top edge, such as between 15 mm and 50 mm or between 20 mm and 40 mm or between 25 mm and 35 mm. A space above the seal and below the re-sealable closure may allow for storage of a scoop.

The re-sealable closure can be used to close the can after the complete or partial removal of the seal for first use. After fully or partially removing the seal, the inner can volume is exposed to the outside. The seal may no longer be suited to cover the can top. As such, the closure may be used to reclose the can after its first opening and prevent contamination.

According to embodiments, the can is a three-piece steel can comprising a topwall, opposite to the base and the topwall and the base are joined to the sidewall at respective seams. The topwall may be provided with an access opening, closed before use by any appropriate means such as the removable seal mentioned above. The large scale production of steel three-piece cans makes the use of three-piece cans cost efficient.

In further embodiments, a reinforcement sleeve made of paperboard material is provided around the sidewall of the can and engages therewith for increasing its mechanical strength. In this context the term ^' mechanical strength’ may be used to describe relevant parameters that determine the useful strength of the sidewall and the can. These may include the axial load resistance of the package, the radial load resistance of the package, and the package’s resistance to dents and puncturing upon impact. It will be understood that as a result of the combination of the can with the sleeve, mechanical strength may be increased with respect to the can alone. The composite construction of embossed metal and paperboard material may be used to improve the mechanical strength. Embossing of the metal can is applied to improve the radial load resistance of the package and make it less prone to denting. In addition, the metal can provides a certain axial load strength, which is further enhanced by a reinforcement sleeve around the sidewall of the metal can. The use of a reinforcement sleeve as a support around a lightweight metal can leads to a package that is just as strong as a standard can, while reducing the use of metal resources. The reinforcement sleeve may extend at least up to a lower peripheral edge of the lid, but may also extend all the way to the upper sidewall edge or the seam with the can topwall.

The metal can and reinforcement sleeve may be produced separately and assembled later. This may make the production process more cost efficient and moreover allows for easy separation of the two materials after use. As such, the different materials may be recycled separately after use, which makes the composite can environmental friendly.

The material costs of the proposed package may be lower, as the additional costs of a reinforcement sleeve may be marginal in comparison to the costs saved by using less metal. In an embodiment, the metal can sidewall thickness is less than 0.14 mm and may be less than 0.12 mm and even as low as 0.1 1 mm or 0.10 mm. A can with similar dimensions without an embossed sidewall would require a sidewall thickness of 0.18 mm to reach the same axial load strength. A can with similar dimensions with an embossed sidewall would require a sidewall thickness of 0.14 mm to reach the same axial load strength. Hence up to 20% reduction in metal costs in comparison to an embossed can and 40% reduction in metal costs in comparison to a flat walled can may be achieved using the reinforcement sleeve.

Reference to paperboard is intended to relate to card, carton or cardboard like products, being generally thicker than paper and being intended to have a degree of compressive mechanical strength within the plane of the material. Such strength may be achieved by the increased thickness orweight and/or due to the structural shape. In certain embodiments, paperboard may refer to paper products having an area weight of greater than 100 g/m ² . The paperboard may be a cellulose pulp based product comprising virgin pulp or recycled paper pulp or a mixture thereof.

According to certain embodiments, the paperboard may be a corrugated material. Here the term“corrugated” indicates that the material consists of a fluted or folded corrugated sheet, which may be attached to one or two flat liners. The corrugated material may for instance be corrugated card, corrugated paper, or corrugated fiberboard. Corrugated materials are easy to customize as they are flexible, easy to fold, and their thickness can be easily adjusted. Moreover, corrugated material has a high impact resistance and high tear resistance, thereby providing an extra protective layer around the metal can. This may further prevent the metal can from denting or puncturing when in contact with a sharp object.

In addition, an outer liner of the corrugated material i.e. a liner at the outer surface of the sleeve, may be printed to customize the package. This provides the possibility to use the sleeve for branding the product, and to make it visually attractive. The reinforcement sleeve thereby has a dual function: reinforcing the metal can and providing a wrapper for the product. In preferred embodiments, the corrugations of the corrugated material extend vertically. The corrugated material is lightweight with a high strength-to-weight ratio, so that the use of corrugated material in a reinforcement sleeve especially increases the axial load strength of the package without significantly increasing the weight of the package. It will be understood that although corrugated paper based materials have been discussed, other structures for the paperboard material may be used, including honeycomb or cell-based structures, which may be exclusively paper based or may comprise other materials.

In further embodiments, the package may further comprise one or more gripping regions for improving a user’s grip on the sidewall of the can. The gripping regions may preferably be made by providing cut-outs through the reinforcement sleeve. If the user’s grip on the sidewall of the can is improved, it will be easier for the user to apply a force to the package in order to separate the lid from the container. The gripping region may also encourage a user to place their hands at the correct location for opening the package, for instance by visual and/or tactile instructions, and in the correct orientation to correctly initiate separation for recycling. As the gripping regions may be formed by cut-outs in the reinforcement sleeve, revealing the embossed metal with for instance a heart or star shaped pattern, the gripping regions may serve an aesthetic purpose also.

According to an embodiment, the reinforcement sleeve may comprise a tear-band allowing part of the sleeve to be torn off, whereby, after tearing off the tamper band access is provided to allow for removal of the lid or removal of the sleeve for recycling is possible.

As noted above, the package may have any appropriate cross-sectional shape such as a square or rectangular surface with either sharp or rounded-off corners. In certain preferred embodiments, the package has a cylindrical shape.

The package may also be provided in any appropriate size. The typical shelf life of infant nutrition or milk formula after first opening of a can is a few weeks (e.g., 2 to 4 weeks). Therefore the can size is preferably dimensioned to contain just enough formula for this period. In preferred embodiments, the package has a height between 8 cm and 25 cm, preferably between 10 cm and 20 cm; and is suited for containing between 0.5 and 1 .5 kg of infant milk formula. Nevertheless smaller sizes of packages may also be made available, for example for use during shorter trips.

Short description of drawings

The present invention will be discussed in more detail below, with reference to the attached drawings of an exemplary embodiment, in which

Fig. 1 shows a cut-away perspective view of a package according to a first embodiment;

Fig. 2 shows a detail of part of the sidewall of the package of Fig. 1 ; and

Fig. 3 shows a perspective view of a package according to a second embodiment.

Description of embodiments

Figure 1 shows a cut-away perspective view of a first embodiment of a package 1 for powdered infant nutrition according to the present invention, comprising a can 2, a reinforcement sleeve 3, and a re-sealable closure, which in this embodiment is a removable lid 4. The can 2 is cylindrical and comprises a can base 21 , a can sidewall 22 and a can topwall 24 surrounding an access opening 26. The reinforcement sleeve 3 extends around the can sidewall 22, starting from a lower sidewall edge 25 at the can base 21 , up to an upper sidewall edge 23. The lid 4 is removable and can be used to open and reclose the package 1 . Beneath the lid 4, a seal 6 covers the access opening 26. The seal 6 is in the form of a thin foil and has a pull tab 7 that can be used for peeling back the seal for removal prior to first use.

The can 2 is of generally conventional construction, sometimes referred to as a three-piece seamed can. The base 21 and the topwall 24 are connected to the sidewall 22 at folded seams at the upper sidewall edge 23 and the lower sidewall edge 25. A vertical seam (not shown) is also present where the sidewall 22 has been joined to itself to form a cylinder. The height of the sidewall 22 is 155 mm, the diameter of the sidewall is 130 mm and the sidewall is formed of steel having a gauge of 0.12 mm. The skilled person will recognise that other dimensions and constructions may also be contemplated without departing from the scope of the present claims.

The reinforcement sleeve 3 is made of corrugated cardboard, with a flat outer liner 32, a flat inner liner 33 and a fluted corrugated sheet 35 therebetween, with the corrugations extending vertically. The reinforcement sleeve 3 also comprises sleeve cut-outs 31 that make the can sidewall 22 visible from the outside. As can be seen through the cut-out 31 , the can sidewall 22 is provided with embossing in a recurring pattern of embossed contours 52 that, in this embodiment, form closed contours in the shape of hearts. It will be understood that other shapes forming both open and closed contours may be used for the contours 52 . The size, length and orientation of the contours 52 may be selected according to the manner in which the can 2 is to be strengthened.

The construction of the sidewall 22 and the reinforcement sleeve 3 can be seen in greater detail in Figure 2. The figure is not to scale. In the illustrated embodiment, the embossed contours 52 are formed by protrusions 53 extend outwards from the outer surface 27 of the can sidewall 22. On the inner surface 29 of the can sidewall 22 a corresponding depression 55 is formed. The skilled person will be well aware of how such embossing may be provided using e.g. embossing rollers or presses or the like. In the illustrated embodiment, the sidewall 22 has been deformed such that the protrusions 53 extend outwards. In other embodiments these protrusions may extend inwards from the inner surface 29 of the can sidewall 22. Also shown in Figure 2 is an adhesive 60, which lightly adheres the sidewall 22 to the reinforcement sleeve 3, comprising flat outer liner 32, flat inner liner 33 and fluted corrugated sheet 35 therebetween.

The outwardly extending embossed contours 52 on the can sidewall 22, in combination with the one or more sleeve cut-outs 31 in the sleeve 3, provide one or more gripping regions 5 for improving a user’s grip on the can sidewall 22 and package 1 .

The lid 4 is of generally conventional form and made of a resilient plastic material that allows it to be applied over and lightly grip the upper sidewall edge 23 in an interference fit. In this embodiment, it also covers an upper portion of the reinforcement sleeve 3.

In use, the user may remove the lid 4, giving access to the inner volume of the package 1 . The seal 6 can then be removed by application of a force to the pull tab 7. Product may then be dispensed and the package 1 reclosed by application of the lid 4. Figure 3 shows a perspective view of a second embodiment of a package 101 similar to the first embodiment, but carried out without a reinforcement sleeve and with a different type of re- sealable closure 104. Like the first embodiment, the can 102 is a cylindrical three-piece seamed can, having a base 121 , a sidewall 122 and a topwall 124. The height and diameter of the can are the same as in the first embodiment but the sidewall is formed of steel having a gauge of 0.14 mm.

On the sidewall 122, embossing is provided in a recurring pattern of embossed shapes in the form of open contours 152. The contours 152 are formed by depressions 155 extending inwards, reaching a maximum depth of 0.3 mm relative to the planar surface of the sidewall 122. Hence the outer surface 127 of the can sidewall 122 is essentially planar with depressions 155. This makes the can highly suited for adhering a label or sleeve to brand and/or reinforce the package (not shown). The skilled person would realize that the embossing applied in this embodiment may be replaced by the embossing in the first embodiment and vice-versa as the selected embossing may depend on both the mechanical and aesthetical effects that one would like to achieve.

The re-sealable closure 104 is made of plastic material. It comprises a lid 141 , a circumferential rim 142 defining an aperture 160, a hinge 143 and a locking mechanism 144 and is shown with opened lid 141 . The rim 142 is configured around the top peripheral wall 124 of the can 102, gripping around the inner sidewall surface 129 and the outer sidewall surface 127. The rim 142 is fixed irremovably to the sidewall of the can 102 by adhesive. Yet the skilled person would understand that there are also other ways to mount the rim 142 on the can 102.

The lid 141 is hinged to the rim 142 with hinge 143. This hinge has a pivot axis perpendicular to the vertical axis. In this embodiment, the hinge 143 is made of plastic formed by a fold line, which allows the closure to be made in one piece. Alternatively, the hinge may be made in a way that it hinges a rim 142 and lid 141 that are manufactured separately.

The rim 142 comprises an outer circumferential wall 145 that extends at the side of the outer surface 127, an inner circumferential wall 146 that extends along the inner surface 129 of the sidewall 122, and a thin upper rim 147 that extends on the top side of the rim. The lid 141 also comprises an outer circumferential wall 148 and an inner circumferential wall 149. These walls are spaced apart at a distance slightly larger than the thickness of the upper rim 147. Therefore, when the lid is closed, the upper rim 147 is enclosed by the outer circumferential wall 148 and the inner circumferential wall 149 of the lid 141 . In closed condition, the outer circumferential wall 148 of the lid visually extends the outer circumferential wall 145 of the rim. This makes the package 101 with closure 104 visually attractive.

The locking mechanism 144 may be used to reseal the package 101 . The locking mechanism 144 connects a lid portion 181 , which is hingedly connected to the outer circumferential wall 148 of the lid 141 , with the rim 142 via a clicking mechanism. The lid portion 181 comprises a gap 183 which under a pressure exerted by a finger or thumb may be pushed to engage with an extending portion 184 of the rim 142. This extending portion 184 extends outwards of the side of the upper rim 147.

Unlocking of the lid 141 is effectuated by a manual actuation of the lid portion 181 radially outward. A recess 182 in the outer circumferential wall 145 of the rim provides sufficient space to place a thumb or finger on the rim 142, below the lid portion 181 . By exerting a small pressure on the lid portion 181 , the locking mechanism 144 is unlocked. In alternative embodiments, different locking mechanisms may be deployed, such as a for instance a hooking mechanism, where the lid 141 is hooked around the rim 142.

Below the inner circumferential wall 146 of the rim, a seal 106 is connected to the top wall

124 to cover the access opening 126. The seal 106 is in the form of a thin foil and has a pull tab 107 that can be used for peeling back the seal for removal prior to first use. In Figure 3, the seal 106 has already been broken, revealing the access opening 126. The seal is placed about 40 mm below the upper rim 147. This provides sufficient space to allow for placement of a scoop 171 under the lid 141 . In this embodiment, the scoop 171 is clicked on the inner surface of the lid 141 but alternatively the re-sealable closure could be configured to allow for placement of the scoop 171 elsewhere, such as on the inner circumferential wall 146.