WO2009127783A1

WO2009127783A1 - Heat-sealed package and a packaging blank for forming the same

Info

Publication number: WO2009127783A1
Application number: PCT/FI2009/050274
Authority: WO
Inventors: Jari RÄSÄNEN
Original assignee: Stora Enso Oyj
Priority date: 2008-04-14
Filing date: 2009-04-14
Publication date: 2009-10-22
Also published as: FI20085310L; EP2276673A4; FI20085310A0; EP2276673A1; EP2276673B1; ES2456867T3

Abstract

The invention relates to a heat-sealed package (1) of a polymer-coated fiber- based material, such as paper or paperboard, as well as to a packaging blank intended for its fabrication. The package comprises a bottom (2), side and end walls (3, 4, 5), as well as a top (6), and is formed by folding from a packaging blank provided with corresponding segments. According to the invention, the package is closed by sealing together the blank's abutted edge flaps in such a way that the latter make up a ridge (7) co-directional with the package side walls and protruding from the package top, the ridge constituting the only sealing line to hold the package together. The package can have its gables and bottom provided with fold lines for making the package collapsible at the gables and compressible to a flat condition when empty. The package is suitable for use e.g. as a candy, snack or lunch package that can be filled and closed at sales outlets.

Description

Heat-sealed package and a packaging blank for forming the same

The invention relates to a heat-sealed package made from a polymer-coated fiber- based material, such as paper or paperboard, which comprises a bottom, side and end walls, as well as a top, and which has been formed by folding from a packaging blank provided with corresponding segments. In addition, the invention relates to a packaging blank intended for forming such a package.

Particularly milk, cream, sour milk products, juices, and wine are commonly packed in parallelogram-shaped or ridge-topped, so-called gable top cartons, which are heat sealed from polymer-coated paperboard. Packaging blanks are supplied to a packaging machine in a continuous web, which the machine first bends and seals for a tube into which the packaged product is introduced, and then chops the filled-up tube for individual packages while closing the packages at same time by sealing the same at the bottom and top. At a vertical joint present on a side of the package, the edges of a blank become overlapped, and at the package ends, the segments of a blank corresponding thereto become folded for a flat bottom as well as for a flat top of the parallelogram-shaped package or for a ridge top of the gable top package, depending on the shapes, fold lines, and dimensioning of a blank. Hence, the closed package develops three sealing lines, on a ver- tical side of the package and at each end of the package. Such packages and the packaging technology required thereby lend themselves well to factory-scale packaging with a packaging machine. On the other hand, they are not suitable for small-scale packaging in which the packed product consists not of a running liquid but of a solid matter, possibly sizable solid pieces, and in which, as opposed to liquid containers, the package is not filled to the brim.

US Patent publication 5,314,112 discloses a parallelogram-shaped portfolio folded from a blank of paperboard, which is intended for storing sheets of paper or documents. The portfolio is of such a construction that its permanent assembled condition does not require sealing or other such fasteners. The blank sheet, from which the portfolio is foldable, is rectangular in shape and thereby considerably simpler in terms of its shape and fold lines than those required by sealed liquid containers as described above.

Publication WO 99/16675 discloses a cube-shaped carton box, which is foldable simply from a quadratic blank, wherein fold lines define a diagonal cross which constitutes a bottom and a vertical side for the box, and the blank's triangular corners are foldable for a top of the box. The cube-shaped box has not been sealed and its purpose is indeed to open and spread out for use e.g. as a game board. On the other hand, the box and blank design is such that closing the box by heat sealing would not even be possible.

Accordingly, there is a demand for a rectangular or other such simple basic outline blank for a foldable package, which is closable by a simple, single-step heat sealing process of blank panels abutted against each other. Another objective within the scope of the invention is to find an application, wherein a regular rectangle- shaped blank is foldable and heat-sealable for a tightly closed package whose liquid and gas tightness are defined by the barrier properties of a coating polymer.

A heat-sealed package of the invention, as defined in the foregoing introduction, is characterized in that the package has been closed by sealing together the packaging blank's abutted edge flaps in such a way that the latter make up a ridge co- directional with the side walls of the package and protruding from the package top, the ridge constituting the only sealing line to hold the package together.

Thus, in terms of its construction, the package is a bundle gathered up around its edges, the integrity of which is up to the heat sealing of a polymer coating present at the edges. If the packaging material is polymer-coated on both sides, all materi- al layers of the sealing line shall bond to each other over the entire surface area thereof the same way as in a laminate. If, in addition, the blank is rectangular in shape, its edges shall extend all the way to the package ridge constituted by a sealing line, whereby the package is closed in a liquid and gas tight manner by the sealing. The number of sealing lines needed for a package being just one, the package lends itself to a post-filling closing procedure by means of a simple heat sealer established by heatable jaws pressing against each other. The closed package is openable by tearing the sealing line open, starting from either end of the package. If the sealing joint is opened only partially, the package forms a draining aperture the way of a pouring spout, whereby the package contents need not be drained out at one time. If the packaging material comprises thin polymer-coated paper, its opening is also implementable by tearing off partially or completely the package ridge formed by the joint. If the sealing joint is torn open all the way, the package spreads open and exposes its contents all at once. This is particularly handy in the case of lunch packages containing e.g. sandwiches or similar snacks. Sealed product packages according to the invention are suitable for industrial fabrication, but a particularly beneficial application for the invention can be found in stores, kiosks and the like sales and distribution outlets, in which the packages can be filled and closed in small production batches or even one at a time, ac- cording to customers' orders. Notable products to be packed according to the invention include snacks and traveling lunches, whereby a single package can be adapted to contain even several different products or ingredients, including cutlery, disposable dishes, and small pouches of condiments and flavors. The package contents may also consist of a single dry product, to mention for example coffee, tea, spices, candy, cereal, popcorn, etc.

Depending on the measurements of various segments included in a blank that makes up a package of the invention, the blanks comprising basically corresponding segments and fold lines can be used for forming a parallelogram-shaped package or ridge-topped gable top package, wherein the top consists of sloping side panels interconnected by a sealed top ridge. A particularly preferred embodiment for a package of the invention comprises a gable top package, having its bottom provided with a longitudinal fold line co-directional with the package side walls and the package having its gables provided with vertical and inclined fold lines to make the package collapsible at its gables. This makes it possible for the packag- ing blank to be folded consistently with the package and then flattened to enable stacking the blanks in such a flattened condition. Such pre-folded blanks resemble bags, making the filling and closing thereof particularly convenient at a sales or distribution outlet. A further benefit is that, as its draining progresses, the package collapses to a more flattened condition to claim less space, and a half-empty package is easy to carry along, for example in a pocket.

The package according to the invention can be folded and sealed from a rectangu- lar packaging blank. Such blanks can be supplied to a store or a distribution outlet where the packages are fabricated, preferably in the form of a rolled-up continuous web. Thus, the lines between successive blanks must be provided with perfora- tions or other such weaknesses for easy separation of the blanks. The web of blanks can also be pleated for a zigzag-shaped stack or the blanks may come in separate stacked sheets.

Another virtue of the rectangular packaging blank is that, in the process of folding a blank for a package, the blank's edge turns up over its entire length to extend along the sealing-line forming ridge of the package. Since the packaging material has a polymer coating on both sides thereof, the blank's edges become sealed to each other in full extent for a leakproof joint. The resulting liquid and aroma tight package is particularly suitable for dry, powdered products, such as coffee, tea or condiments, which may be subjected to a prolonged storage before the package is opened. On the other hand, it is also possible within the concept of the invention that the edges of an otherwise rectangular blank be truncated, i.e. the outermost edge flap only extends around the blank over part of its circumference. What is achieved by this is that a reduced number of packaging material layers are gathered up along a sealing line of package ridge, making the package heat sealable with less thermal energy. At its most reduced form, the sealing line may only be provided with two overlying packaging material layers sealable together, whereby it is also possible that the material be polymer-coated on just one side. This type of package is difficult to make totally leakproof at its gables, but the closure is still sufficient e.g. for snack and lunch packages with contents intended for immediate consumption. A packaging blank of the invention, which is made of a polymer-coated fiber-based material, such as paper or paperboard, and which is provided with segments corresponding to a bottom, side and gable walls, as well as a top of the package and separated from each other by fold lines, as well as with flaps abutting each other in the process of folding the blank and being sealable to each other for closing the package, is characterized in that the blank has the edge flaps which in an abutted condition make up a ridge, which protrudes from the package top and which constitutes the only sealing line holding the package together.

The invention will now be described in more detail by way of examples with reference to the accompanying drawings, in which Fig. 1 shows one rectangular-shaped packaging blank of theHnvention along with its fold lines and segments defined thereby, fig. 2 shows a gable top type package formed from the blank of fig. 1 by folding and sealing, fig. 3 shows a gable for the package of fig. 2, fig. 4 shows, the same way as fig. 3, a gable for a parallelogram-shaped package of the invention, fig. 5 shows a rectangular-shaped packaging blank according to a second embodiment of the invention, fig. 6 shows a collapsible package formed from the blank of fig. 5,

fig. 7 shows a gable for the package of fig. 6, fig. 8 shows a substantially rectangular-shaped packaging blank according to a third embodiment of the invention, having its sealable edge flap truncated, and fig. 9 shows a packaging blank according to a fourth embodiment of the invention, which is a variation from the blank of fig. 8.

The gable top type package 1 visualized in figs. 2 and 3 comprises a horizontal bottom 2, vertical side walls 3 and end walls 4, gable triangles 5, a top consisting of two sloping side panels 6, as well as a protruding ridge 7 at an apex formed by the side panels 6. The package's bottom 2 side walls 3, upright end walls 4, and the top's side panels 6 are rectangular in shape, and the gable triangles 5 consist of inward-folded triangular segments defined by fold lines 8. The package 1 consists of a bilaterally extrusion-coated packaging material, the coating of which comprises a heat-sealable polymer, such as e.g. polyethylene. The package is closed in a water and air tight manner by sealing together the layers of packaging paper which make up the ridge 7.

The packaging blank 9 visualized in fig. 1 , from which the package 1 of figs. 2 and 3 is foldable and heat-sealable, consists of a rectangular-shaped sheet of packaging paper. The blank 9 comprises segments 2a-7a, corresponding to the package parts 2-7 and defined by the fold lines 8. The edge flap 7a, extending around the blank 9, has its segments pleating on top of each other in the folding process and bonding to each other in the heat-sealing process the same way as in a laminate, resulting in the protruding ridge 7 holding the package together. Segments 10a, present in the blank's 9 corners, are pleated inside the package in the process of folding the package 1.

The package's 1 dimensions, i.e. its width, height, the steepness of its top 6, and the protrusion of its ridge 7, can be varied by modifying the measurements of the blank's 9 various segments 2a-7a. In the extreme event that the top's side segment 6a has an area which half of the bottom's 2 area, the package turns out in the shape of a parallelogram as depicted in fig. 4.

Figs. 5-7 illustrate, as in figs. 1-3 respectively, a second embodiment of the invention, which only differs from that shown in figs. 1-3 in the sense that the package has its bottom 2 provided with a longitudinal fold line 8' co-directional with the side walls 3, and the package has its end walls 4 provided with inclined fold lines 8" and upright fold lines 8'". This results in a package collapsible transversely in the direction of the end walls 4, in which the end walls 4, provided with the fold lines 8" and 8'", are pleated inwards. The empty package is compressible to complete flat- ness and enables stacking in this condition.

The packaging blanks 9 shown in figs. 8 and 9 are modifications of that shown in fig. 1 , having the edges thereof narrowed by removing parts of the blank-circling edge flap 7a of fig. 1. This is a way of reducing the number of packaging paper layers sealable to each other and pleating in abutment with each other along the package ridge 7. In the case of fig. 8, the edge flap 7a is only retained alongside the segments 6a making up the top's side panels, such that the package has its ridge 7 only consisting of two layers of packaging paper sealable to each other. A partial removal of the edge flap 7a may weaken the tightness of a closed package but, on the other hand, the package is sealable more conveniently and with a lesser amount of heat needed for the softening or melting of polymer. _o

It is obvious for a skilled artisan that the embodiments of the invention are not limited to the described examples, but that variations can be made within the scope of the appended claims.

Claims

1. A heat-sealed package (1 ) made from a polymer-coated fiber-based material, such as paper or paperboard, which comprises a bottom (2), side and end walls (3, 4, 5), as well as a top (6), and which has been formed by folding from a pack- aging blank (9) provided with corresponding segments (2a-6a), characterized in that the package (1 ) has been closed by sealing together abutted edge flaps (7a) of the blank (9) in such a way that the flaps make up a ridge (7) co-directional with the side walls (3) of the package and protruding from the top (6) of the package, the ridge constituting the only sealing line to hold the package together.

2. A package as set forth in claim 1 , characterized in that it is a gable top type package (1 ), in which the top consists of sloping side panels (6) interconnected by the sealed top ridge (7).

3. A package as set forth in claim 2, characterized in that the package bottom (2) has a longitudinal fold line (8¹) co-directional with the package side walls (3) and the package gables (4) have vertical and inclined fold lines (8", 8'"), such that the package is collapsible at its gables.

4. A package as set forth in claim 1 , characterized in that the package is parallelogram in shape.

5. A package as set forth in any of the preceding claims, characterized in that it has been formed by folding from a rectangular packaging blank (9).

6. A package as set forth in any of claims 1-4, characterized in that the package (1 ) has been formed by folding from a blank (9), which is rectangular in shape with the exception that its edge flaps (7a) have been truncated for reducing the number of material layers abutting each other along a sealing line of the package ridge (7).

7. A package as set forth in any of the preceding claims, characterized in that it is a coffee, tea, condiment, candy, snack or lunch package.

8. A package as set forth in claim 5, characterized in that it is a liquid and aroma tight food package.

9. A packaging blank (9), which is intended for making a package (1 ) as set forth in any of the preceding claims and which is made of a polymer-coated fiber-based material, such as paper or paperboard, and which is provided with segments (2a- 6a) corresponding to a bottom (2), side and end walls (3, 4, 5), as well as a top (6) of the package and separated from each other by fold lines (8), as well as with flaps (7a) abutting each other in the process of folding the blank and being seala- ble to each other for closing the package, characterized in that the blank has edge flaps (7a) which in an abutted condition make up a ridge (7), which protrudes from the package top (6) and which constitutes the only sealing line holding the package together.

10. A blank as set forth in claim 9, characterized in that it is rectangular in shape, comprising a continuous edge flap (7a), which extends around the blank (9) and which is sealable for the package ridge (7).

11. A blank as set forth in claim 9, characterized in that it is rectangular in shape with the exception that its edge flaps (7a) have been truncated for reducing the number of material layers abutting each other along a sealing line of the package ridge (7).

12. A blank as set forth in any of claims 9-11 , characterized in that segments (2a, 4a), which make up the package's bottom (2) and end walls (4), are provided with fold lines (8', 8", 8'") for enabling the collapsibility of a gable top type package.

13. A blank as set forth in any of claims 9-12, characterized in that the blank (9) is made of a fiber-based packaging material with a polymer coating on both sides thereof.