HK1071555B - Stand-up pouch for packaging food products and the method of manufacturing the stand-up pouch - Google Patents

Description

Stand-up pouch for packaging food products and method for making same

Technical Field

The present invention relates to a stand-up pouch for packaging food products.

Background

As is known, many food products, in particular pourable food products such as fruit juice, UHT (ultra-high-temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of aseptic packaging material.

The packaging material has a multilayer structure comprising a layer of fibrous material, e.g. paper, covered on both sides with layers of heat-seal plastic material, e.g. polyethylene, and, in aseptic packages for long-storage products, such as UHT milk, comprises a layer of oxygen-barrier material, which is formed, for example, by an aluminium film laminated to a layer of heat-seal plastic material, which in turn is covered with another layer of heat-seal plastic material eventually forming the inner surface of the package contacting the food product.

A typical example of such a package is a parallelepiped-shaped package for liquid or pourable food products, such as tetra brik Aseptic (registered trade mark), which is formed by a continuous tube of packaging material, said tube being obtained in the following manner: bending and longitudinally sealing the web of packaging material; sterilizing the web of packaging material on the packaging machine by applying a chemical sterilizing agent, such as a hydrogen peroxide solution, which sterilizing agent is removed from the surface of the packaging material after sterilization, for example by evaporation by heating; and maintaining the sterilized web of packaging material in a closed, sterile environment, folding and longitudinally sealing it to form a vertical tube.

The tube is filled with a sterile or aseptic treated food product, and the tube is sealed and cut at equally spaced cross sections to form pillow packs (pillow packs) which are then mechanically folded at their ends to form a final package which is relatively rigid and of a defined geometry. More specifically, in the final package, the longitudinal seal of the tube extends vertically along the side walls of the package, while the transverse seals, which form the ends of the pillow packs, are folded and sealed onto the bottom and top walls of the package.

A variant of the usual hexahedral package can be obtained by: folding the pillow pack so that the transverse seals are along the opposite side walls of the pack and the longitudinal seal is on the bottom wall so that the top wall is free; an example of such A variant is shown in patent US-A-4312450, which is particularly convenient when an opening device is to be used.

One of the main advantages of the packaging technique using a continuous tube of packaging material is that very high production speeds can be achieved.

Another way of packaging the product is to use a so-called stand-up pouch, i.e. a flexible pouch made from a roll of packaging material and having a "corrugated" bottom wall and two surfaces sealed together along three sides.

The stand-up pouch is typically made from a single piece of material having a W-structure forming a bottom wall and two surfaces, or from two or three different pieces of packaging material sealed together.

Stand-up pouches have been used in a wide variety of products, with several advantages over other packaging techniques: stand-up pouches are very portable because they do not have a fixed shape with stiff or rigid sections or corners, require only a small amount of packaging material per unit weight of product, are aesthetically pleasing, and have good shelving ability.

However, the production of stand-up pouches requires special form and fill machines which are costly and slow, and therefore costly for the overall package.

Disclosure of Invention

It is an object of the present invention to provide a new stand-up pouch which can be produced from a continuous tube of packaging material with only minor modifications to existing continuous form-fill machines, for example for producing hexahedral packages.

In order to achieve the above object, the present invention provides a stand-up pouch made from a web of packaging material, comprising a bottom wall, a front wall and a rear wall, and a top wall, the top wall forming, together with the bottom wall, the front wall and the rear wall, a single piece of packaging material folded into a tube, the top wall having two opposite edges connected by a first seal, the front wall and the rear wall being connected to each other by a second seal extending along and transversely to respective side edges of the front wall and the rear wall, the bottom wall and the top wall being folded between the front wall and the rear wall and having respective side edges folded in half and sealed between the side edges of the front wall and the side edges of the rear wall, characterized in that the side edges of the bottom wall and the side edges of the top wall have respective pre-lamination holes, each of the pre-lamination holes exposing an intermediate layer of the packaging material, the intermediate layers are opposed to each other when the side edges of the bottom wall and the side edges of the top wall are folded in half and sealed between the side edges of the front wall and the side edges of the rear wall so as to weld the two halves of the side edges together.

The present invention also provides a method of manufacturing a stand-up pouch having a bottom wall, a front wall, a rear wall and a top wall, wherein the top wall and the bottom wall, the front wall and the rear wall together form a single piece of packaging material, the method comprising the steps of: bending and longitudinally sealing the web of packaging material to form a continuous tube; conveying the tube along a vertical axis; filling the tube with a food product to be packaged so as to maintain a predetermined amount of food product within the tube; pre-forming the tube to produce a front side, a back side, and longitudinally concave V-shaped sides connecting the front and back sides; -heat-sealing the tube transversely by means of a pair of jaws provided with a seal, and-cyclically gripping the tube so as to fold the V-shaped side in half and heat-seal it between the front and rear sides, characterized in that it further comprises: providing pre-lamination holes exposing the intermediate layer of the packaging material on the side edges of the top wall and the bottom wall, folding the side edges of the top wall and the bottom wall in half in such a way that the pre-lamination holes are opposite to each other, sealing the exposed intermediate layer between the side edges of the front wall and the rear wall at the pre-lamination holes, thereby forming a single bag consisting of a portion of a tube and having a first seal formed by a portion of the longitudinal seal of the tube and a pair of second seals constituted by the transverse seals of the tube.

Thus, according to the invention, the stand-up pouch can be produced by a technique similar to that currently used for the manufacture of parallelepiped packages, with only minor modifications to existing continuous form-and-fill machines. Thus, a higher production rate can be obtained and the overall packaging costs are lower compared to known stand-up pouches.

Drawings

Preferred, non-limiting embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a stand-up pouch according to one embodiment of the present invention;

FIG. 2 is a front view of the bag shown in FIG. 1;

FIGS. 3, 4 and 5 are cross-sectional views taken along lines III-III, IV-IV and V-V, respectively, of FIG. 2;

FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4;

figure 7 is a schematic view showing a form and fill apparatus for producing stand-up pouches according to the present invention;

FIGS. 8 and 9 are cross-sectional views taken along lines VIII-VIII and IX-IX;

figure 10 schematically shows a step of a method of manufacturing a stand-up pouch according to the invention; and

figure 11 schematically shows a variant of the method of figure 10 for producing rectangular stand-up pouches.

Detailed Description

With reference to fig. 1-4 and 6, the reference numeral 1 designates as a whole a stand-up pouch, in particular for packaging liquid food 2, such as beverages.

The bag 1 is made of a single piece of laminated packaging material 3 (see the enlarged detail of fig. 5), which laminated packaging material 3 comprises at least a first paper layer 3a, a second oxygen barrier layer 3b (e.g. aluminium foil or mineral coated polymer, e.g. SiO coated), such as_XPET, PA or EVOH), an intermediate hot melt adhesive layer 3c between the first and second layers, and an inner heat seal layer 3d forming the inner surface of the package in contact with the food product.

The bag 1 comprises a bottom wall 4, a top wall 5, a front wall 6 and a rear wall 7 formed by a single piece of a roll of packaging material 3, the packaging material 3 being folded and heat-sealed in tubular form; for example, adjacent edges on the top wall 5 and the rear wall 7, which constitute opposite edges of the sheet of material, are sealed together by a first seal 9. The front wall 6 and the rear wall 7 have a trapezoidal shape with a long base adjacent to the bottom wall 4 and a short base adjacent to the top wall 5, the front wall 6 and the rear wall 7 being heat sealed together by respective seals 10 extending along respective side edges 11 of the walls 6, 7 (fig. 3). The bottom wall 4 and the top wall 5 are folded inwards in a corrugated manner and have respective side edges 12 (figure 5) folded in half between respective side edges 11 of the front wall 6 and the rear wall 7, and the halves 12a, 12b of each edge 12 are oriented towards and heat-sealed to the respective edges 11.

Each half 12a, 12b of the edge 12 is provided with pre-laminated holes 13, i.e. holes made only in the paper layer 3a before the packaging material 3 is laminated. In this way, when making closure 10 and crimping edges 12 between edges 11 of walls 6, 7, halves 12a, 12b are "spot welded" together by adhesion of hot melt intermediate layer 3c exposed through aperture 13. As a result, the side edges 11 of the front wall 6 and the rear wall 7 remain connected to each other over their entire length, as shown in fig. 1.

The method of producing the stand-up pouch 1 will now be described with reference to figures 7-10.

A continuous cylindrical tube 15 is formed in a known manner by bending and longitudinally sealing a web of packaging material. The reference number 16 indicates a continuous longitudinal seal 16 of the tube 15 which will eventually form the seal 9 of the finished bag 1, as will be explained below. The tube 15 is conveyed axially in the vertical direction a and is filled continuously by a known filling device 17, which filling device 17 is partly schematically shown in fig. 7, in order to form a predetermined volume of liquid in the tube.

Downstream of the filling device 17, the tube 15 is pre-shaped by a pre-shaping device 18 comprising a plurality of shaping rollers 19, 20 according to a crease pattern (not shown) provided on the packaging material 3, so as to change it from a circular section (fig. 8) to a substantially polygonal section (fig. 9) having two elongated parallel flat sides 21, 22 which will eventually constitute the front wall 6 and the rear wall 7 of the finished bag 1, and two concave V-shaped sides 23, 24 which will eventually constitute the bottom wall 4 and the top wall 5 of the finished bag 1. The longitudinal seal 16 is along an edge formed between one side 22 of the flat sides 21, 22 and one side 24 of the V-shaped sides 23, 24.

Downstream of the preforming device 18, the tube 15 is heat-sealed transversely by two pairs of jaws 25, known per se, which jaws 25 are driven so as to reciprocate in the direction a and alternately grip the tube 15; as is known, for example, from patent EP- ｃA-1101700, two pairs of jaws 25 interact alternately and cyclically with tube 15 of packaging material and move between an open position (not shown) and ｃA closed position (fig. 7) in which jaws 25 clamp tube 15 of packaging material between respective seals 26, 27, seals 26, 27 being parallel to flat sides 21, 22 of tube 15 and extending transversely with respect to tube 15.

More specifically, if a trapezoidal bag, for example as shown in fig. 1, is to be produced, the seals 26, 27 of the jaw pair 25 are inclined in opposite directions in a vertical plane, thus forming an inclined transverse seal 10 as schematically shown in fig. 10.

When the preformed tube 15 is clamped between the sealing members 26, 27, the V-shaped sides 23, 24 are folded and sealed longitudinally between the flat sides 21, 22; this forms a continuous, alternately oriented bag 1 connected by a seal 10. The bags 1 are finally separated at a cutting line 30 extending along the seal 10, by cutting means (not shown) included in one of the jaws 25 of each pair of jaws or by a cutter located in the downstream jaw 25, so as to obtain the single finished bag 1.

Fig. 11 shows another variant of a method suitable for producing rectangular bags 1', i.e. with parallel sides 11. All of the above description applies to this case, except that the seals 26, 27 of the jaw pair 25 are horizontal and parallel to each other. As a result, the transverse seals 10 of the tubes 15 are parallel.

Finally, it should be noted that modifications may be made to the stand-up pouch without departing from the scope of the invention as defined by the claims. In particular, the outer heat-sealable layer may be provided with a packaging material such that when the closure 10 is manufactured and the edges 12 are folded over, the edges 12 can be sealed together and the bag shape stability ensured without the need for pre-laminated holes 13.

Claims (6)

1. Stand-up bag (1) made from a web of packaging material (3), comprising a bottom wall (4), a front wall (6) and a rear wall (7), and a top wall (5) forming together with them a single piece of packaging material (3) folded into a tube, said top wall having two opposite sides connected by a first seal (9), said front wall (6) and said rear wall (7) being interconnected by a second seal (10) extending transversely along respective sides (11) of said front wall (6) and said rear wall (7) and with respect to said first seal (9), said bottom wall (4) and said top wall (5) being folded between said front wall (6) and said rear wall (7) and having respective sides (12) folded in half and sealed between said sides (11) of said front wall (6) and said sides (11) of said rear wall (7), characterized in that the side edges (12) of the bottom wall (4) and the side edges (12) of the top wall (5) have respective pre-lamination holes (13), each of said pre-lamination holes (13) exposing an intermediate layer (3c) of the packaging material (3), said intermediate layers (3c) being opposite each other when the side edges (12) of the bottom wall (4) and the side edges (12) of the top wall (5) are folded in half and sealed between the side edges (11) of the front wall (6) and the side edges (11) of the rear wall (7) so as to weld the two half-edges (12a, 12b) of the side edges (12) together.

2. Stand-up bag according to claim 1, characterised in that the second seals (10) are inclined towards the top wall (5) and are brought together with each other.

3. Stand-up bag according to claim 1, characterised in that the second seals (10) are parallel to each other.

4. Stand-up pouch according to claim 1, characterised in that the web of packaging material (3) comprises an outer layer (3a), an oxygen barrier layer (3b), an intermediate hot melt layer (3c) between and connecting the outer layer (3a) and the oxygen barrier layer (3b), and an inner heat seal layer (3 d).

5. Stand-up bag according to claim 4, characterised in that the doubled-over side (12) of the bottom wall (4) and the doubled-over side (12) of the top wall (5) each comprise two halves (12a, 12b), the two halves (12a, 12b) being faced and heat-sealed to the respective edge (11) of the front wall (6) or the rear wall (7).

6. A method of manufacturing a stand-up pouch (1) having a bottom wall (4), a front wall (6), a rear wall (7) and a top wall (5), wherein the top and bottom walls, the front and rear walls together form a single piece of packaging material (3), the method comprising the steps of:

bending and longitudinally sealing said web of packaging material (3) to form a continuous tube (15),

conveying the tube (15) along a vertical axis (A),

filling the tube (15) with a food product (2) to be packaged so as to maintain a predetermined amount of food product (2) within the tube (15),

pre-forming the tube (15) to produce a front side (21), a rear side (22) and longitudinally concave V-shaped sides (23, 24) connecting the front and rear sides, and

-heat-sealing the tube (15) transversely by means of a pair of jaws (25) provided with seals (26, 27), and-cyclically gripping the tube (15) so as to fold the V-shaped sides (23, 24) in half and heat-seal between the front side (21) and the rear side (22), characterized in that it further comprises:

-providing pre-lamination holes (13) on the side edges (12) of the top wall (5) and the bottom wall (4) exposing the intermediate layer (3c) of the packaging material, -folding the side edges (12) of the top wall (5) and the side edges (12) of the bottom wall (4) in half in such a way that the pre-lamination holes (13) are opposite each other, -sealing the exposed intermediate layer (3c) between the side edges (11) of the front wall (6) and the side edges (11) of the rear wall (7) at the pre-lamination holes (13), thereby forming a single bag (1, 1') consisting of a portion of a tube and having a first seal (9) formed by a portion of a longitudinal seal (16) of the tube (15) and a pair of second seals (10) constituted by a transverse seal of the tube (15).