The present invention relates to a sheet packaging material for producing sealed packages of pourable food products.
Many pourable food products, such as fruit juice, UHT (ultra-high-temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.
The packaging material has a multilayer structure comprising a base layer, e.g. paper, covered on both sides with layers of heat-seal plastic material, e.g. polyethylene. In the case of aseptic packages for long-storage products the packaging material also comprises a layer of oxygen-barrier material, e.g. aluminium foil, which is superimposed on a layer of heat-seal plastic material, and is in turn covered with another layer of heat-seal plastic material forming the inner face of the package eventually contacting the food product.
Existing packages are normally provided with a detachable portion for opening the package. Using an opening device this portion is partly detached from the rest of the packaging material to free a pour opening through which the product is poured out. The detachable portion is formed on the packaging material prior to folding and sealing the packaging material to form the finished package. The detachable portion normally comprises a prelaminated hole. To form a prelaminated hole a circular hole is first formed solely through the base layer of the packaging material. The circular hole is then covered during lamination of the material with the layers of heat-seal plastic material and barrier material which adhere to one another at the hole thereby forming the prelaminated hole.
Previous efforts have focused on devising an effective, consistent method of opening prelaminated holes that achieves a clean cut about the edge of the pour-out opening without fraying to impair smooth pour-out of the food product.
WO 2011/020634 discloses a sheet packaging material for a sealed package comprising a food pour opening that is formed in use by cutting of an arc-shaped prelaminated strip located around the periphery of a foldable area of packaging material.
Nevertheless, there remains a need to provide improved packaging materials with pour openings that are cheaper to produce and easy to open while maintaining sufficient sealing of the food within the package prior to consumption.
According to one aspect of the present invention, there is provided a sheet packaging material for producing a sealed package of a pourable food product as claimed in claim 1.
According to another aspect of the present invention, there is provided a sealed package for a pourable food product as claimed in claim 6.
Some preferred, non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which:
The package 100 also has a partially laminated opening zone 204 that will be described further below in regard to
The reclosable opening device 300 comprises a frame 304 fitted about the partially laminated opening zone 204. The frame 304 has a pouring spout 308. A removable threaded cap 312 is screwable on and off the frame 304 to close and open the pouring spout 308 respectively, as desired. The opening device 300 also comprises a penetrator 340 located within the interior of the pouring spout 308. The penetrator 340 will be described further below with respect to
The reclosable opening device 300 is made of plastic. The frame 304 is applied to the package 100 by conventional fastening systems such as adhesives, micro-flame, electric-current-induction, ultrasound, laser, or other heat-sealing techniques.
The packaging material 200 from which sealed package 100 is made has a multilayer structure as illustrated in
The base layer 230 may e.g. be carton, paper, paperboard, cardboard, foam, or any other cellulose-based layer suitable for forming a bulk or core layer of a laminated packaging material. The outer layer 234 is intended to protect the base layer towards liquids and dirt, as well as to provide heat sealability properties in a subsequent filling and packaging process. An inner side of the base layer 230 is covered with a similar bonding layer 238 of a thermoplastic polymer, such as conventionally LDPE which is used to laminate, i.e. bind together, a thin, sensitive, layer comprising a gas barrier material, such as for example a thin foil of aluminium 242, to the bulk layer 230. In order to avoid contact between the enclosed product and the barrier material or the aluminium foil 242, the aluminium foil is covered by a polymer layer 246.
In a package formed using a laminated packaging material 200 that includes one of the film laminate 234, 246 embodiments described above, the polymer film 246 of the film laminate is closer to the food product than the substrate, or oxygen barrier material 242. In other words, the polymer film 246 forms the inner side of the package. The polymer film 246 thus needs to be sealable in order to allow heat sealing of two adjacent portions of a laminated packaging material 200. The polymer film 246 also needs to be liquid-tight for ensuring stiffness and rigidity of a bulk layer 230 of the laminated packaging material 200.
Hence, an innermost layer 246 of the laminated packaging material 200 is a heat-sealable layer. An example of a heat-sealable layer is a heat-sealable polyolefin polymer which is applied as a layer to be directed towards the inside of the package, i.e. in direct contact with the food product. The innermost layer may suitably be a heat-sealable polymer such as a polyethylene (PE) polymer of the low density type, selected from the group consisting of LDPE, linear LDPE (LLDPE), Very Low Density PE (VLDPE), Ultra Low Density PE (ULDPE) or metallocene catalyst manufactured LLDPE (mLLDPE) and blends of two or more thereof. Depending on the type of packaging containers produced from the laminated packaging material, heat-sealable innermost layers of high density polyethylene (HDPE), polypropylene (PP) or propylene co- or ter-polymers are also conceivable, as long as they are compatible with and achieve the desired effect in combination with other components of the laminated packaging material.
Suitable examples to be used as innermost layers are blends between LDPE and mLLDPE (e.g. 50/50, 40/60, 60/40, 30/70, 70/30, 20/80, 80/20, 10/90m 90/10, 0/100, 100/0 weight % blend ratios), such as LDPE of extrusion grade, for example having a melt flow index (as determined in accordance with ASTM D1238, 190° C./2.16 kg) of 2-20, such as 2-12, such as 2-7, such as 2-6 and a density (as determined in accordance with ISO 1183, method D) of 914-922 kg/m3, such as 915-920 kg/m3. Examples of mLLDPEs suitable for use in aspects and embodiments described herein have a density less than 0.922 kg/cm3 and a melt flow index (MFI) of 15-25 at 190° C. and 2.16 kg (ASTM 1278). A thickness of the innermost layer 246 of the laminated packaging material 10 is for example between 5 μm-50 μm, such as 10 μm-30 μm, such as 15 μm-25 μm, such as 17 μm-25 μm.
A portion is cut or punched out of the base layer 230 during manufacture of the packaging material 200 to provide a slot 250. Lamination layers 234 and 238 which extend along opposite faces of base layer 230 are sealed together during lamination through slot 250 to provide the laminated cutting area 220 of opening zone 204 which will be described further below.
The partially laminated opening zone 204 in
The four longitudinal portions 220 are spaced apart from each other at optionally equal angles about the centre of the partially laminated opening zone 204. Each removable portion 212 is located between two longitudinal portions 220 in a position opposing another removable portion 212. The removable portions 212 have a folding zone 216 adjacent to the periphery of the opening zone 204 about which the removable portions 212 are folded towards the interior of the sealed package 100 upon opening as will be described below.
Each penetrator 320 and 340 also has a cylinder 328, 348 extending distally from the penetrating members 332, 352 and around the periphery of the penetrators 320, 340. A shaft 336, 356 also extends distally from the penetrating members 332, 352 but along the central longitudinal axis of the penetrators 320, 340. As is evident from
Penetrators 320 and 340 are made from plastic and preferably in one piece by injection molding.
The sealed package 100 is opened as follows. During manufacturing of a filled package, the frame 304 is attached to the package thus covering, or extending away from, the sealed opening zone 204. As explained above the frame 204 is preferably provided with external threads for guiding the cap 312 during assembly.
The cap 312, having corresponding internal threads, is subsequently engaged with the frame 304 by a screwing action. The penetrator 320, 340 is arranged within the cap 312 and is allowed to rotate relative the cap 312 during the screwing action. However, the penetrator 320, 340 is guided in its axial direction relative the cap 312. For this the penetrator 320, 340 may have external threads engaging with internal threads of the frame 304. The threads of the penetrator 320, 340 and the frame 304 may preferably be configured in an opposite direction compared to the threads of the cap 312 such that when screwing the cap 312 onto the frame 304 the penetrator 320, 340 will be lifted upwards. This means that when the cap 312 is screwed onto the frame 302 the penetrator 320, 340 will move axially away from the opening zone 204, but remain in its angular position relative the laminated cutting area 220, 224. For this purpose alignment of the penetrating members 332, 352 relative the laminated cutting area 220, 224 may be performed prior to engaging the cap 312 with the frame 204.
When screwing the cap 312 onto the frame 304, which is preferably made automatically during package manufacturing, the penetrator 320, 340 will be positioned away from the laminated cutting area 220, 224. The package will thus be sealed.
When the package is opened, the cap 312 is unscrewed from the frame 304. Upon this the penetrator 320, 340 will exhibit an axial pressure downwards to push penetrating members 332, 352 through the laminated cutting area 220, 224. This is due to the fact that the penetrator 320, 340 will move axially downwards when the cap 312 moves axially upwards. Penetrating the laminated cutting area 220, 224 also partly detaches removable portions 212 from the packaging material 200. Application of pressure is continued after the laminated cutting area 220, 224 has been pierced by penetrating members 332, 352 so that the cylinder 328, 348 comes into contact with, and inwardly folds, the removable portions 212 about the folding zones 216. The applied pressure is then discontinued upon finishing unscrewing the cap 312. A large proportion of the penetrator 320, 340 is then contained below top wall 104 within the interior of the package 100. The annular flange 324, 344 not only imparts strength to the penetrator 320, 340 but also sits on or slightly above the top wall 104 to prevent the penetrator 320, 340 from completely falling into the food product within the package 100.
The penetrator 320, 340 stays in its position upon removing the unscrewed cap 312. Hence the penetrator 320, 340 will be disengaged from the cap 312 and remain its position relative the frame 304 such that the penetrator 320, 340 is fixed to the frame 304 along with the removal of the cap 312.
The food product may then be poured, optionally through channels roughly bounded by the penetrating members 332, 352 and the partly detached removable portions 212. If desired, the cap 312 may be screwed back onto the frame 304 to close the pouring spout 308 so that the food product can be kept in the package 100 for consumption later.
The opening action described above is called a one-step opening, since penetration is performed simultaneously as the cap 312 is unscrewed.
In another embodiment the penetrator 320, 340 may be separated from the interior of the cap 312, however still enclosed within the cap 312. Upon unscrewing the cap 312 the customer will have access to the penetrator 320, 340. The penetrator 320, 340 is thereafter manually pushed through the laminated cutting area 220, 224 in order to open the package. This opening action is usually called a two-step opening since unscrewing of the cap 312 and penetration are two separate and consecutive steps. The two-step opening may in some cases be preferred since the user may inspect the laminated cutting area 220, 224 before penetration, thus ensuring seal integrity.
The laminated cutting area 220, 224 of packaging material 200 has a smaller surface area than existing circular or round laminated areas which allows for a reduction in the amount of material that is cut or punched out of the base layer 230 during manufacturing. This decreases the production losses (less base layer 230 to discard) and lowers the manufacturing cost while the package 100 remains easy to open with no detrimental impact on the food preservation and pouring efficiency. The relatively small laminated area of the partially laminated opening zone 204, 234 also results in a package 100 with a lower oxygen transmission rate (OTR) as less of the package interior is potentially exposed to the outer environment.
The penetrator 320, 340 allows for fast and efficient opening of the package 100 in one swift vertical movement via penetration of laminated cutting area 220, 224 and folding of removable portions 212.
Number | Date | Country | Kind |
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16175861 | Jun 2016 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2017/065308 | 6/21/2017 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2017/220692 | 12/28/2017 | WO | A |
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Entry |
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Search Report and Written Opinion received in International Application No. PCT/EP2017/065308 dated Sep. 20, 2017. |
Number | Date | Country | |
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20200031518 A1 | Jan 2020 | US |