EP1291290A1 - Stand-up pouch for packaging food products - Google Patents

Abstract

A stand-up pouch (1) made from a continuous tube(15) of web packaging material (3) and including a basewall (4), a top wall (5), a front wall (6) and a backwall (7); the front wall (6) and back wall (7) are joinedtogether by seals (10) extending along their respectivelateral edges (11) and formed by transversally sealingthe tube (15) of web packaging material (3), base and topwalls (4, 5) are folded between the front and back walls(6, 7) and have respective lateral edges (12) doubled andsealed between the lateral edges (11) of front wall (6)and back wall (7).

Description

• The present invention relates to a stand-up pouchfor packaging food products.
• As is known, many food products, in particularpourable food products such as fruit juice, UHT (ultra-high-temperatureprocessed) milk, wine, tomato sauce,etc., are sold in packages made of sterilized packagingmaterial.
• The packaging material has a multilayer structurecomprising a layer of fibrous material, e.g. paper,covered on both sides with layers of heat-seal plasticmaterial, e.g. polyethylene, and, in the case of asepticpackages for long-storage products, such as UHT milk,also comprises a layer of oxygen-barrier materialdefined, for example, by an aluminium film which issuperimposed on a layer of heat-seal plastic material andis in turn covered with another layer of heat-sealplastic material eventually defining the inner face ofthe package contacting the food product.
• A typical example of such a package is theparallelepiped-shaped package for liquid or pourable foodproducts known as Tetra Brik Aseptic (registeredtrademark), which is formed from a continuous tube ofpackaging material obtained by bending and longitudinallysealing a web packaging material; the web of packaging material is sterilized on the packaging machine itself,e.g. by applying a chemical sterilizing agent, such as ahydrogen peroxide solution, which, after sterilization,is removed, e.g. vaporized by heating, from the surfacesof the packaging material; and the web of packagingmaterial so sterilized is maintained in a closed sterileenvironment, and is folded and sealed longitudinally toform a vertical tube.
• The tube is filled with the sterilized or sterile-processedfood product, and is sealed and cut at equallyspaced cross sections to form pillow packs, whose endsare then folded mechanically to form the finishedpackage, which is relatively rigid and has a definedgeometry. More particularly, in the finished package, thelongitudinal seal of the tube extends vertically along alateral wall of the package, the transversal sealsforming the ends of the pillow pack are folded and sealedagainst the base and top wall of the package.
• A variant of the usual parallelepiped-shapedpackages is obtained by folding the pillow pack so as todispose the transversal seals along opposite lateralwalls of the package and the longitudinal seal on thebase wall, so as to leave the top wall free; an exampleof this variant, which is particularly convenient in viewof the application of an opening device, is shown in US-A-4312450.
• A major advantage of the packaging technology usinga continuous tube of packaging material is the high production speed.
• An alternative way of packaging products is the useof so-called stand-up pouches, i.e. flexible pouches madefrom web packaging material and having a "bellows-like"base wall and two faces sealed together along threesides.
• Stand-up pouches are generally made either from asingle piece of web material in a W configuration formingthe base wall and the two faces, or from two or threedifferent pieces of packaging material sealed together.
• Stand-up pouches are used for a high variety ofproducts, and compared to other packaging technologieshave some advantages: stand-up pouches are convenientlyportable since they have no fixed shape with hard orrigid parts or corners, require little mass of packagingmaterial per unit of product weight, and have aestheticalappeal and good shelf presence.
• However, the production of stand-up pouches requiresdedicated forming and filling machines which are costlyand relatively slow, so that the overall packaging costis relatively high.
• An aim of the present invention is to provide a newstand-up pouch that can be manufactured from a continuoustube of packaging material with little modifications toexisting continuous forming-filling machines, such as theones used for producing parallelepiped packages.
• This aim is achieved by a stand-up pouch made from aweb packaging material and including a base wall, a front wall and a back wall, characterised by comprising a topwall forming with said base, front and back walls asingle piece of packaging material folded in a tubularfashion and having two opposite edges joined together bya first seal, said front wall and said back wall beingjoined together by second seals extending alongrespective lateral edges of said front wall and said backwall and transversely with respect to said first seal,said base and top walls being folded between said frontand back walls and having respective lateral edgesdoubled and sealed between said lateral edges of saidfront wall and said back wall.
• The invention also relates to a method ofmanufacturing stand-up pouches including the steps of:
• bending and longitudinally sealing a web ofpackaging material so as to form a continuous tube,
• feeding said tube along a vertical axis,
• filling said tube with a food product to be packagedso as to maintain a predetermined level of product withinsaid tube,
• pre-forming said tube so as to produce a front side,a back side and two longitudinal concave, V-shaped sidesconnecting said front and back sides, and
• transversally heat-sealing said tube by means ofpairs of jaws provided with sealing members andcyclically gripping said tube so as to double and heat-sealsaid V-shaped sides between said front and backsides, thereby forming individual pouches which are constituted by tube portions and have a first seal formedby a portion of the longitudinal seal of said tube and apair of second seals which are constituted by transversalseals of said tube.
• According to the present invention, therefore, thestand-up pouches can be produced by means of a technologysimilar to the one used at present for manufacturingparallelepiped packages, with few modification ofexisting continuous forming-filling machines. Therefore,a high production rate can be obtained, and the overallpackaging cost is very low when compared to known stand-uppouches.
• A preferred, non-limiting embodiment of the presentinvention will be described by way of example withreference to the accompanying drawings, in which:
• Figure 1 is a perspective view of a stand-up pouchaccording to an embodiment of the present invention;
• Figure 2 is a front view of the pouch of figure 1;
• Figures 3, 4 and 5 are sections taken along linesIII-III, IV-IV and V-V, respectively, of Figure 2;
• Figure 6 is a section taken along line VI-VI ofFigure 4;
• Figure 7 is a schematic view showing a forming andfilling unit for producing stand-up pouches according tothe present invention;
• Figure 8 and 9 are sections taken along lines VIII-VIIIand IX-IX;
• Figure 10 shows schematically a step of a method of manufacturing stand-up pouches according to the presentinvention; and
• Figure 11 shows schematically a variant of themethod of figure 10 for manufacturing stand-uprectangular pouches.
• With reference to figures 1-4 and 6,numeral 1references as a whole a stand-up pouch, particularly forpackaging aliquid food product 2, e.g. a drink.
• Pouch 1 is manufactured from a single piece oflaminated packaging material 3 (see enlarged detail offigure 5) including at least afirst paper layer 3a, asecond oxygen-barrier layer 3b (e.g. an aluminium foil ora mineral-coated polymer such as a SiOx-coated PET, PA orEVOH), an intermediate hot-meltadhesive layer 3c betweenthe first and second layers and an internal heat-seallayer 3d defining the inner face of the packagecontacting the food product.
• Pouch 1 includes abase wall 4, atop wall 5, afront wall 6 and aback wall 7 formed from a single webofpackaging material 3, which is folded and heat-sealedat in tubular fashion; e.g. respective adjacent edges oftop wall 5 andback wall 7, which constitute oppositeedges of the web, are sealed together by a first seal 9.Front wall 6 andback wall 7 have a trapezoidal shapewith the longer base adjacent tobase wall 4 and theshorter base adjacent totop wall 5, and are heat-sealedtogether by means ofrespective seals 10 extending alongrespectivelateral edges 11 ofwalls 6, 7 (figure 3).Base wall 4 andtop wall 5 are inwardly folded in abellows-like fashion, and have respectivelateral edges12 which are doubled between the respective lateral edges11 (fig. 5) offront wall 6 andback wall 7, with eachhalf 12a, 12b of eachedge 12 facing and being heat-sealedto arespective edge 11.
• Eachhalf 12a, 12b ofedges 12 has a pre-laminatedhole 13, i.e. a hole made only in thepaper layer 3abefore laminating thepackaging material 3. In thismanner, whenseals 10 are made andedges 12 are doubledbetweenedges 11 ofwalls 6, 7,edge halves 12a, 12b are"spot-welded" together by the adhesion of the respectivehot-meltintermediate layers 3c that are exposed thoughholes 13. As a result,lateral edges 11 offront wall 6andback wall 7 remain attached to one another throughouttheir length, as shown in figure 1.
• With reference to figures 7-10, a method ofproducing the stand-up pouch 1 as described is thefollowing.
• A continuouscylindrical tube 15 in formed, in knownmanner, by bending and longitudinally sealing a web ofpackaging material. Numeral 16 references a continuouslongitudinal seal oftube 15, which eventually will formseals 9 of the finishedpouches 1 as hereafter explained.Tube 15 is axially fed along a vertical direction A, andcontinuously filled by a knownfilling device 17,partially and schematically shown in figure 7, to form apredetermined head of liquid within the tube.
• Downstream from thefilling device 17,tube 15 ispre-formed according to a crease pattern (not shown)provided on thepackaging material 3 by apre-formingdevice 18 including a plurality of formingrollers 19,20, thereby passing from a circular cross section (fig.8) to a substantially polygonal cross-section (fig. 9)having two elongated parallelflat sides 21, 22 whicheventually will constitutefront wall 6 andback wall 7of the finishedpouches 1, and two concave V-shaped sides23, 24 which eventually will constitutebase wall 4 andtop wall 5 of the finishedpouches 1.Longitudinal seal16 is located along an edge formed between one (22) ofthe flat sides (21, 22) and one (24) of the V-shapedsides 23, 24.
• Downstream from thepre-forming device 18,tube 15is transversally heat-sealed by two pairs ofjaws 25, perse known, which are driven so as to reciprocate alongdirection A and alternatelyclamp tube 15; as is known,e.g. from EP-A- 1 101 700, the two pairs ofjaws 25interact alternately and cyclically with thetube 15 ofpackaging material, and are movable between an openposition (not shown) and a closed position (figure 7) inwhich thejaws 25 grip thetube 15 of packaging materialbetweenrespective sealing members 26, 27 which areparallel toflat sides 21, 22 oftube 15 and extendtransversally with respect totube 15.
• More particularly, if trapezoidal pouches such asthe one of figure 1 are to be produced, the sealingmembers 26, 27 of the pairs ofjaws 25 are inclined in avertical plane in opposite directions, so as to forminclinedtransversal seals 10 as schematically shown infigure 10.
• Whenpre-formed tube 15 is clamped between sealingmembers 26, 27, V-shaped sides 23, 24 are longitudinallydoubled and sealed betweenflat sides 21, 22; asuccession of alternately-orientedpouches 1 linked byseals 10 is therefore formed.Pouches 1 can eventually beseparated by a cutting device (not shown) incorporated inonejaw 25 of each jaw pair, or by a knife locateddownstream jaws 25, atcut lines 30 extending along andwithinseals 10, so as to obtain individual finishedpackages 1.
• Figure 11 shows a variant of the method adapted toproduce rectangular pouches 1', i.e. havingparalleledges 11. All the preceding description applies, exceptthat the sealingmembers 26, 27 of the pairs ofjaws 25are horizontal and parallel with one another. As aconsequence, thetransversal seals 10 oftube 15 areparallel.
• Finally, it should be noted that stand-up pouches asdescribed may be modified without departing from thescope of the present invention as defined by the claims.In particular, the packaging material may be providedwith an external heat-seal layer, so that whenseals 10are made andedges 12 are doubled, they are sealedtogether and ensure shape stability of the pouch without the need to provide pre-laminatedholes 13.

Claims (8)

1. A stand-up pouch (1) made from a web packagingmaterial (3) and including a base wall (4), a front wall(6) and a back wall (7),characterised by comprising atop wall (5) forming with said base, front and back walls(4, 5, 6) a single piece of packaging material (3) foldedin a tubular fashion and having two opposite edges joinedtogether by a first seal (9), said front wall (6) andsaid back wall (7) being joined together by second seals(10) extending along respective lateral edges (11) ofsaid front wall (6) and said back wall (7) andtransversely with respect to said first seal (9), saidbase and top walls (4, 5) being folded between said frontand back walls (6, 7) and having respective lateral edges(12) doubled and sealed between said lateral edges (11)of said front wall (6) and said back wall (7).
2. A pouch as claimed in claim 1,characterised inthat said second seals (10) are inclined and convergewith one another towards said top wall (4).
3. A pouch as claimed in claim 1,characterised inthat said second seals (10) are parallel to one another.
4. A pouch as claimed in any of the precedingclaims,characterised in that said web packaging material(3) includes an outer layer (3a), an oxygen-barrier layer(3b), an intermediate, hot-melt layer (3b) interposedbetween and connecting said outer layer (3a) and oxygen-barrierlayer (3b), and an internal heat-seal layer (3d).
5. A pouch as claimed in claim 4,characterised in that said doubled lateral edges (12) of said top andbottom walls (6, 7) include, each, two halves (12a, 12b)facing and heat-sealed to a respective edge (11) of saidfront or back wall (6, 7).
6. A pouch as claimed in claim 5,characterised inthat said lateral edges (12) of said top and bottom wallshave respective prelaminated holes (13) on each half(12a, 12b), said holes (13) exposing said intermediatelayer (3c) and facing one another when said lateral edges(12) of said top and bottom walls (6, 7) are doubled andsealed between said lateral edges (11) of said front wall(6) and said back wall (7) so as to weld together saidhalves (12a, 12b).
7. A pouch as claimed in claim 5,characterised inthat said web packaging material (3) includes an externalheat-seal layer providing for heat-sealing together saidhalves (12a, 12b) of said lateral edges (12) of said topand bottom walls (6, 7) when said lateral edges (12) ofsaid top and bottom walls (6, 7) are doubled and sealedbetween said lateral edges (11) of said front wall (6)and said back wall (7).
8. A method of manufacturing a stand-up pouch asclaimed in any of the preceding claims, including thesteps of:

   bending and longitudinally sealing a web ofpackaging material (3) so as to form a continuous tube(15),

   feeding said tube (15) along a vertical axis (A),

   filling said tube (15) with a food product (2) to bepackaged so as to maintain a predetermined level ofproduct (2) within said tube (15),

   pre-forming said tube (15) so as to produce a frontside (21), a back side (22) and two longitudinal concave,V-shaped sides (23, 24) connecting said front and backsides (21, 22), and

   transversally heat-sealing said tube (15) by meansof pairs of jaws (25) provided with sealing members (26,27) and cyclically gripping said tube (15) so as todouble and heat-seal said V-shaped sides (23, 24) betweensaid front and back sides (21, 22), thereby formingindividual pouches (1, 1') which are constituted by tubeportions and have a first seal (9) formed by a portion ofthe longitudinal seal (16) of said tube (15) and a pairof second seals (10) which are constituted by transversalseals (10) of said tube (15).

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