Patent Description:
It is commonly known to use a paperboard based packaging material to form product containers, such as containers for enclosing and storing liquid food.

In order to ensure the required quality of the final package, e.g. in terms of food safety and integrity, the packaging material may comprise different layers. As an example, a packaging material may comprise a core layer of paper or paperboard with at least one polymeric composition or layer applied on one side thereof making up the outer surface of the final package, and a polymeric composition or layer on the opposite or inner side. The polymeric composition on the inner side may in some cases be provided with a protective film such as aluminum; the polymeric composition thus normally also includes an outer layer being in contact with the product intended to be contained in the final package. Usually, an additional polymeric composition is applied to the protective film in order to avoid direct contact between the foodstuff contained in the package and the protective layer itself in order to prevent the foodstuff from wetting the aluminium and other layers in the laminate.

Product containers formed by the above-mentioned packaging material may be provided with a pre-laminated hole, e.g. in order to facilitate the use of a straw which upon use is inserted into the package via the pre-laminated hole. At the hole, the core layer is missing such that only the outer and inner polymeric layers which optionally may including the protective film sandwiched between them, are covering the hole.

During manufacturing of such packaging material the core layer is processed by punching holes in it, and thereafter lamination in one or more steps is performed. This process is commonly known as "converting".

Forming and filling of the individual product containers or packages is performed by the use of a filling machine, which typically includes a plurality of consecutive process stations. For example, the filling machine may have an infeed station for receiving a web of packaging material, a sterilization station for sterilizing the web of packaging material, a tube forming station in which the web is continuously formed into a tube by sealing the lateral edges of the web, a filling station for filling the tube with a product, a sealing station for providing transversal seals to the tube and for cutting sealed packages from the upstream tube, and a final folding station for shaping the package into its final shape.

Another example of a filling machine uses pre-made blanks to form individual packages.

The pre-laminated hole is normally arranged on the upper portion of the final package, located at an area extending between one edge of the upper end and the upper transversal seal. As the pre-laminated hole introduces a local weakness of the packaging material there is a risk that the upper portion of the package will wrinkle undesirably in the vicinity of the pre-laminated hole. Any wrinkle will occur during sealing and/or final forming of the package which means that there are very limited possibilities to adjust or fine tune the operation of these filling machine stations during production, especially since the production speed of the filling machine is very high.

<CIT>, <CIT> and <CIT> disclose examples of known packaging materials.

The present solution aims at least partly overcoming one or more of the above-identified limitations of the prior art. In particular, it aims at reducing the formation of wrinkles near the pre-laminated hole of a packaging material during sealing and/or forming of the package. A packaging material according to the present invention is set out in claim <NUM>.

One aspect of the present solution is a packaging material comprising a laminate with a core material layer and the packaging material has a plurality of delimited areas intended to form faces of a package. At least one delimited area is provided with at least one pre-laminated hole and at least one compressed feature arranged adjacent to the pre-laminated hole. The at least one feature comprises at least one line extending along at least a part of the perimeter of the pre-laminated hole.

The delimited area may be intended to form an upper end of the package. Preferably the pre-laminated hole is intended to form a straw hole of the package, whereby the straw hole is positioned at an area easily accessible for a customer.

The at least one compressed feature may be arranged within <NUM> from the pre-laminated hole, such as within <NUM>-<NUM>. Tests have shown that such distance between the pre-laminated hole and the compressed feature greatly reduces the formation of wrinkles in the final package.

The at least one compressed feature may be formed by embossing, debossing, or compression.

Referring to the at least one line above, it may be straight, and two straight lines may extend on opposite sides of the pre-laminated hole.

The at least one line may be curved, and two curved lines may extend on opposite sides of the pre-laminated hole.

Each curved line may extend between <NUM>° and <NUM>° of the periphery of the pre-laminated hole.

The curved line may form a circular line extending along the entire periphery of the pre-laminated hole.

The at least one feature may comprise at least one line extending from the periphery of the pre-laminated hole and radially away from the pre-laminated hole.

According to a second aspect, a package as set out in claim <NUM> is provided. The package comprises a packaging material according to the first aspect, wherein the packaging material is closed by seals to form a closed package.

According to a third aspect a method for providing a packaging material as set out in claim <NUM> is provided. The method comprises: provide a core material layer with at least one hole, laminate the core material layer in order to form a laminated packaging material with a pre-laminated hole, and provide at least one compressed feature adjacent to the pre-laminated hole prior to or after the core material layer is provided with at least one hole. The at least one feature comprises at least one line extending along at least a part of the perimeter of the pre-laminated hole.

Still other objectives, features, aspects and advantages of the present solution will appear from the following detailed description as well as from the drawings.

Embodiments of the present solution will now be described, by way of example, with reference to the accompanying schematic drawings, in which.

With reference to <FIG> an example of a package <NUM> is illustrated. The package <NUM> represent a commercially available liquid food package called Tetra Prisma®. As can be seen in <FIG>, the package <NUM> comprises a relatively flat upper end <NUM> being provided with a straw hole <NUM>. The straw hole <NUM>, as will be explained later, is formed by a pre-laminated hole of the packaging material <NUM> used for producing the package <NUM>.

The upper end <NUM> represents one of a plurality of delimited areas 11a-f of the packaging material <NUM>. Each delimited area 11a-f is intended to form a face of the package <NUM> produced by the packaging material <NUM>. It should be understood that not all delimited areas 11a-f are indicated in <FIG>, and each area 11a-f may be delimited from adjacent areas 11a-f e.g. by means of crease lines.

The package <NUM> is formed from a web of packaging material <NUM>, which is formed into a tube by sealing the longitudinal edges of the packaging material <NUM> to each other. The longitudinal sealing <NUM> can be seen in <FIG> as extending along the upper end <NUM>, but as is evident the longitudinal sealing <NUM> runs along the entire package <NUM>. When the tube is filled with its intended content the package <NUM> is sealed and cut from the tube by providing top and bottom transversal seals. In <FIG>, only the top transversal seal <NUM> is shown. For final forming two upper flaps 16a, 16b are folded and attached to a main body <NUM> of the package <NUM>. Although not shown, the final shape of the bottom end is achieved in a similar manner although the flaps are folded inwards. The final forming of the package <NUM> is preferably made by utilizing the crease lines.

In <FIG> the packaging material <NUM> used for producing the package <NUM> is shown in further details. The cross-section is taken along line A-A in <FIG>.

The packaging material <NUM> comprises a core material layer <NUM>, an outer layer <NUM>, and an inner layer <NUM>, wherein the outer layer <NUM> and inner layers <NUM> are applied to opposite sides of the core material layer <NUM> after the at least one hole is cut. Hence, the core material layer <NUM> is provided with holes prior to converting, i.e. before one or more lamination process are performed in order to produce the final packaging material <NUM>. The holes, which may be formed in a sequential pattern onto a web of the core layer, or individually on separate blanks, are preferably punched.

The outer layer <NUM> applied to one side of the core material layer <NUM> is adapted to provide the outer surface of the package <NUM> to be produced, which outer surface and outer layer <NUM> faces the surroundings of the package. The inner layer <NUM> is applied to the other side of the core material layer <NUM> and is adapted to provide the inner surface of the package <NUM> to be produced which is in contact with the product contained in the package <NUM>.

The core material <NUM> may be a sheet for providing rigidity to the packaging material <NUM>, and may preferably be made of material such as paper board or cardboard.

The outer layer <NUM> may comprise at least one layer of polymer material, which is applied to the core material layer <NUM> in a lamination process. Moreover, one of the layers making up the outer layer <NUM> may be a decorative layer making up the outer surface of the package <NUM> to be formed.

A printing layer may be included onto the core material layer <NUM>, adjacent to the outer layer <NUM>.

The inner layer <NUM> may comprise at least one layer of polymer material. As is shown in <FIG> a first and inner layer 24a is provided facing the product to be enclosed by the package <NUM>. A protective layer 24b may be present between the core material layer <NUM> and the inner layer 24a. The protective layer 24b may be a foil, such as a metal foil, preferably an aluminium foil. The protective layer 24b protects against oxygen and light to maintain the nutritional value and flavours of the food product inside the package <NUM> at ambient temperatures.

In addition, a lamination layer 24c may be present between the protective layer 24b and the core material layer <NUM>. The lamination layer 24c may be at least one layer of polymer material.

According to one embodiment, the inner layer <NUM> of the packaging material <NUM> intended for the inside of the finished package <NUM>, which is in contact with the product contained in the package <NUM> comprises starting from the core material layer <NUM>: a lamination layer 24c, a protective layer 24b and an sealing layer 24a. The lamination layer 24c enables the core material <NUM> to stick to any protective layer 24b applied. The sealing layer 24a enables package sealing.

The polymer layers <NUM>, 24a, 24c of the packaging material <NUM> may be of any suitable type of polymer material, preferably a plastic material such as polyethylene.

Now turning to <FIG> the upper end <NUM> of the package <NUM> is shown in further detail. It should be noted that the upper end <NUM> of <FIG> is intended to represent any part of a package <NUM> being provided with a pre-laminated hole <NUM> in the packaging material <NUM>, such that the following description is applicable also for other types of packages <NUM> than shown in <FIG>. Such packages may e.g. include parallelepipedic packages like Tetra Brik®, gable-top packages like Tetra Rex®, etc..

The pre-laminated hole <NUM> is normally arranged somewhere between one lateral end of the upper end <NUM> and the transversal seal <NUM>, which may be located centrally across the upper end <NUM>.

During sealing and/or forming of the upper end <NUM> shown in <FIG> it is, as explained above, possible that wrinkles W occur in the packaging material <NUM>. Tests have shown that the wrinkles, when occurring, are present in an area A extending between the edges of the pre-laminated hole <NUM> towards the transversal seal <NUM>. Especially, the area A extends approximately ±<NUM>° from a virtual line X representing the shortest distance between the pre-laminated hole and the transversal seal <NUM>, as indicated in <FIG>. This means that essentially no wrinkles have been observed outside the area A. It has further been observed that the problem of wrinkles becomes more pronounced with an increasing diameter of the pre-laminated hole <NUM>.

In <FIG> a first embodiment of a solution to avoid the formation of wrinkles is shown. The inventors have surprisingly found that by providing one or more features <NUM> adjacent to the pre-laminated hole <NUM> compression forces in the packaging material <NUM>, occurring during sealing and/or forming of the final package <NUM>, will be absorbed to a greater extent thus preventing the formation of wrinkles in the packaging material <NUM>.

As can be seen in <FIG>, such features <NUM> may be realized by providing two symmetrical lines 30a, 30b in the packaging material on each side of the pre-laminated hole <NUM>. Each line 30a, 30b is effected by altering the core material layer <NUM> e.g. by embossing, debossing, and/or compression, and each line 30a, 30b preferably extends at least along the entire diameter D1 of the pre-laminated hole <NUM>, in a direction towards the transversal seal <NUM>. However, in some embodiments each line 30a, 30b may have a length which is shorter than the diameter D1 of the pre-laminated hole <NUM>.

Especially, the lines 30a, 30b do not intersect with the transversal seal <NUM> but are interrupted at a distance from the transversal seal <NUM>. Advantageously, the lines 30a, 30b are provided prior to lamination of the packaging material <NUM>, and by having a distance between the end of each line 30a, 30b and the area of the transversal seal <NUM> the packaging material <NUM> is smooth and homogeneous at the transversal seal <NUM> thus improving the integrity of the seal <NUM>.

The thickness D2 of each line 30a, 30b may be in the range of <NUM>,<NUM> - <NUM>, or slightly above that. Moreover, the shortest distance D3 between the pre-laminated hole <NUM> and the line 30a, 30b should preferably be above <NUM>,<NUM>, such as <NUM>. The diameter D1 of the pre-laminated hole may typically be in the range of <NUM>-<NUM>.

The method of providing the features <NUM> may be made in different ways, as illustrated in <FIG>. As is shown in <FIG> the core material layer <NUM> may be processed such that its otherwise planar shape is altered into a relief pattern corresponding to the shape of the lines 30a, 30b. This may be achieved either by embossing or debossing, depending on the final design of the package <NUM>. For embossing the outside of the packaging material <NUM> is raised (as is shown in <FIG>), while debossing provides a sunken pattern at the outside of the packaging material <NUM>.

In <FIG> the features <NUM> are formed by compressing the core material layer <NUM>, however using a planar anvil thus preventing the pattern to protrude on the outside.

In any of the above-described examples, the core material layer <NUM> will to some extent be compressed at the area of the feature(s) <NUM>. For the example of <FIG> the entire feature will be a compressed pattern. Although the feature <NUM> of <FIG> will form a deflection from the originally flat shape on both sides of the core material layer, a compression of the core material layer will in fact be present as the shape of the outer side will not be identical to the shape of the inner side.

Normally the packaging material <NUM> is provided with a series of crease lines for defining the folding lines used during forming and sealing of the package <NUM>. Advantageously the features <NUM> may therefore be provided in the same creasing process, thus removing the need for separate process steps.

Other examples of features <NUM> which have been verified to reduce the problem of wrinkles at the area around the pre-laminated hole <NUM> are shown in <FIG>. Each feature <NUM> discussed in the following will provide a compression in the core material layer and may either be formed as an indentation (i.e. a purely compressed feature) on the inner or outer side, an indentation on the inner side and a boss on the outer side (i.e. an embossed feature), or a boss on the inner side and an indentation on the outer side (i.e. a debossed feature). The thickness of each feature <NUM> is essentially similar to the thickness D2 described with reference to <FIG>.

Starting in <FIG>, the packaging material <NUM> is provided with two features <NUM> in the vicinity of the pre-laminated hole <NUM>. Each feature <NUM> is formed as a curved line 30c, 30d surrounding and tracing a part of the periphery of the pre-laminated hole. The curvature of each line 30c-d is preferably designed such that the distance between the line 30c-d and the perimeter of the pre-laminated hole <NUM> is constant. Each line 30c-d may extend in the range of <NUM>-<NUM>°, and the lines 30c-d are preferably separated from each other at both ends.

In <FIG> another example is shown. Here only one feature <NUM> forms a circular line 30e surrounding the pre-laminated hole <NUM>. The radial distance between the feature 30e and the pre-laminated hole <NUM> is preferably selected such that the circular line 30e does not intersect with the transversal seal <NUM>.

In <FIG> the feature <NUM> is provided as a semi-circular, or curved, line 30f arranged in the area between the pre-laminated hole <NUM> and the transversal seal <NUM>. The line 30f may extend in the range of <NUM>-<NUM>°, preferably symmetrically around line X.

In <FIG> another embodiment is shown, wherein the feature <NUM> is formed as a straight line <NUM> extending from the pre-laminated hole <NUM> towards the transversal seal <NUM>. Preferably, the line <NUM> coincides with the vertical line X. As explained above the line <NUM> should be interrupted at a small distance from the transversal seal <NUM>.

Another example is shown in <FIG>. The features <NUM> are here provided as two spaced apart lines <NUM>-i, extending at an angle relative each other. The lines <NUM>-i are symmetrically arranged relative the virtual line X, and they may be arranged to cover an angular distance of approximately ±<NUM>° relative the virtual line X. As for the line <NUM> shown in <FIG>, the lines <NUM>-i are interrupted such that they do not intersect the transversal seal <NUM>.

In <FIG> the feature <NUM> is formed as a circular line 30j surrounding the pre-laminated hole <NUM>. Compared to the feature 30e shown in <FIG> the circular line 30j is arranged immediately adjacent to the pre-laminated hole. The circular line 30j is associated with a number of advantages. For example, it is possible to ensure perfect centering of the line 30j by using the punching device to form the feature <NUM>. Moreover, lamination of the packaging material over the punched hole will be easier since the thickness of the core material layer <NUM> will be reduced, especially if the feature 30j is formed by compression.

Now turning to <FIG> methods <NUM> will be described, whereby the method <NUM> is performed in order to provide a packaging material <NUM> as described above. According to <FIG> the method <NUM> is performed by a first step <NUM> in which a core material layer <NUM> is provided with at least one hole. In a subsequent step <NUM> the core material layer <NUM> is laminated in order to form a laminated packaging material <NUM> with a pre-laminated hole <NUM>. The method <NUM> further comprises a step <NUM> in which at least one compressed feature <NUM> is arranged adjacent to the pre-laminated hole <NUM>.

The compressed feature <NUM> may be provided prior to lamination of the core material layer <NUM>, as indicated in <FIG>.

In an even more preferred method <NUM>, shown in <FIG>, the step <NUM> of providing the compressed feature(s) is performed prior to the step <NUM> of providing the at least one hole, and the step <NUM> of laminating the core material layer <NUM>.

Claim 1:
A packaging material, comprising a laminate with a core material layer (<NUM>)and having a plurality of delimited areas (11a-g) intended to form faces of a package (<NUM>) by means of crease lines, wherein at least one delimited area (<NUM>) is provided with at least one pre-laminated hole (<NUM>); characterized in that the at least one delimited area (<NUM>) is provided with at least one compressed feature (<NUM>), other than the crease lines, wherein the at least one compressed feature (<NUM>) is arranged adjacent to the pre-laminated hole (<NUM>), the at least one compressed feature (<NUM>) comprises at least one straight line (30a-b, <NUM>-i) and the pre-laminated hole (<NUM>) has only one diameter.