Tear open pouch

Abstract

 A pouch for containing a flowable material manufactured in a vertical form, fill and seal process wherein a pouch is formed from a sheet of thermoplastic film and a transverse heat seal formed between pouches as they are filled serves as a top closure for a lower pouch and a bottom closure for an upper pouch, wherein the pouch is provided with an easy open feature just above or below a respective closure, which comprises a second seal formed between two layers of film in a portion of an edge of the pouch that is in close proximity to and extends inwardly from a corner of the pouch to provide a tear line to open the pouch, and process for manufacturing.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a pouch for containing flowable materials which is easy to tear open, a heat sealing assembly for a vertical form, fill and seal machine for use in manufacturing the pouch, and a process for manufacturing the pouch.

BACKGROUND OF THE INVENTION

[0002] Packaging pouches are typically made on vertical form, fill and seal machines. Using such a machine, a flat web of synthetic thermoplastic film is unwound from a roll and formed into a continuous tube in a tube forming operation, by sealing the longitudinal edges of the film together to form a lap seal or a fin seal. The tube thus formed is pulled vertically downwards to a filling station. The tube is then collapsed across a transverse cross-section of the tube, the position of the cross-section being at a sealing device below the filling station. A transverse heat seal is made by the sealing device at the collapsed portion of the tube, thus making an airtight seal across the tube. The sealing device generally comprises a pair of jaws. After making the transverse seal, but before the jaws of the sealing device are opened, a quantity of material to be packaged, for example a liquid is caused to enter the tube at the filling station, and to fill the tube upwardly from the aforementioned transverse seal. The tube is then caused to move downwardly a predetermined distance. This movement may be under the influence of the weight of the material in the tube, or it may be caused by pulling or mechanically driving the tube. The jaws of the sealing device are closed again, thus collapsing the tube at a second transverse section. The second transverse section may be above, usually just above the air/material interface in the tube, or the second transverse section may be below the air/material interface. The sealing device seals and severs the tube transversely at the second transverse section. The material filled portion of the tube is now in the form of a pillow shaped pouch. Thus the sealing device has sealed the top of the filled pouch and sealed the bottom of the next to be formed pouch, all in one operation. The filling of the product may be conducted on a continuous or intermittent basis. One such vertical form, fill and seal machine of the type described above is sold under the trade-mark PREPAC. Other suitable machines are sold under the trade-marks INPACO and ELECSTER.

[0003] There are other types of machines wherein the sealing device does not sever the tube at the second transverse section, but does sever the tube subsequently. In order to package certain flowable but viscous materials, it is often desirable to heat the material. When such is the case, the packaging process is often referred to as a hot-fill process.

[0004] A variety of flowable materials may be packaged in this manner, for example, milk, syrups, sauces, juices, water and the like. The term "flowable material" is meant to encompass materials which are flowable under gravity or may be pumped. Such materials may include emulsions, pastes, peanut butter, preserves, dough, ground meat, powders, detergents, oils and granular solids. It is anticipated that this pouch could be used for containing flowable materials, in particular foods that are packaged under sterile, pasteurized or aseptic conditions.

[0005] The pouches produced through this type of process can be manufactured to contain any volume of flowable material. In the situation where drinking fluids are packaged in this fashion, a typical size might be 250 mls or 500 mls. In such instance, it is possible to consume the fluid directly from the pouch. Thus, providing a pouch that includes an easy tear opening for this purpose is desirable since it avoids the necessity to use an implement such as a knife or scissors. In addition, because these packages are meant to be one-time use packages it is appropriate that the manner in which they are manufactured is as economical as possible, without sacrificing the basic packaging requirements for the materials in question.

[0006] There are many advantages to the present invention such as the economical single step manufacturing process, and the lack of any requirement for a cutting device of any sort, either in manufacturing or opening the pouch.

[0007] Many solutions have been proposed for producing packages of this type, and typically such packages have included a notch or tear line which allows the package to be opened. Examples of the solutions offered included those found in U.S. Patent No. 3,759,439 issued September 18, 1973 to Cross, et al., U.S. Patent No. 4,176,567 issued December 4, 1979 to Weisberg, U.S. Patent No. 4,890,744 issued January 2, 1990 to Lane, Jr., et al. and U.S. Patent No. 5,470,419 issued November 28, 1995 to Sasaki, et al. These structures typically involve providing a notch or tear line in the sealed area of the pouch or by other means, such as that found in U.S. Patent No. 5,470,419 which provides strings in the plastic film when it is made by melt extrusion. Another solution is found in U.S. Patent No. 4,176,567, wherein a sealed marginal portion of a flat bag is punctured by a uniquely shaped tool head having a faceted tapered tool head. The faceted tapered tool head is provided with preferably three and, in any event, not many facets producing a corresponding number of straight, longitudinally extending, bag-cutting edges converging to a bag puncturing point at the end of the tool head. Thus, the process here requires an additional step after the bag has been manufactured and the contents sealed, as well as the use of the tool that is meant to puncture the sealed area of the bag. Another example is found in the previously referenced U.S. Patent No. 3,759,439 which includes a flexible reinforcement having a highly localized line of weakness, the reinforcement being bonded to the surface of the film or incorporated partly or wholly within its thickness. Again a complicated solution that would seem to involve additional costs in the manufacture of the packaged product.

[0008] Reference may also be had to U.S. Patent No. 5,038,550 which describes sealing the edge of a pouch with a semicircular heat seal with a slit therein. See Figure 11 of this patent. The slit in this case is cut into the edge of the pouch and has an isolating seal closely around it, and then a contoured seal further out.

[0009] Thus there is a need to produce an easy open pouch for packaging purposes that is simple in design and, easy and economical to manufacture.

SUMMARY OF THE INVENTION

[0010] The present invention seeks to provide a pouch that can be easily torn open which can be manufactured using a vertical form, fill seal apparatus which permits the formation of a tear line simultaneously with the sealing of the pouch.

[0011] Thus the present invention provides in one aspect a pouch for containing a flowable material manufactured in a vertical form, fill and seal process wherein a pouch is formed from a sheet of thermoplastic film and a transverse heat seal formed between pouches as they are filled serves as a top closure for a lower pouch and a bottom closure for an upper pouch, wherein the pouch is provided with an easy open feature just above or below a respective closure, which comprises a second seal formed between two layers of film in a portion of an edge of the pouch that is in close proximity to and extends inwardly from a corner of the pouch to provide a tear line to open the pouch.

[0012] In another aspect, the invention provides a heat sealing assembly for use in a vertical form, fill and seal apparatus for sealing at least two layers of thermoplastic film together, comprising a first jaw and a second jaw, a first and a second electrical impulse heat sealing element mounted on the first jaw, at least one of said jaws being capable of transverse motion and adapted to collapse a tubular film made from said thermoplastic film and to allow the film to pass between said jaws, the first electrical impulse heat sealing element being about the length of the width of the collapsed tubular film so that the flattened tube can be sealed and cut, and the second electrical impulse heat sealing element mounted on the first jaw being in close proximity to the first element and arranged so that the seal it creates extends from one edge of the collapsed tube for a short distance towards the interior of the tube so that a second seal can be made in the tube to provide a tear line for opening the pouch.

[0013] In yet another aspect, the invention provides a process for manufacturing a pouch for containing a flowable material which comprises forming a thermoplastic film into a film tube by forming a vertical fin seal or lap seal in the tube, drawing the tube through a heat sealing assembly of a vertical form, fill and seal apparatus, collapsing the tube, forming a first transverse seal in the tube, continuously filling the tube with a flowable material, allowing the filled tube to drop down a predetermined distance from the heat sealing assembly, collapsing the filled tube and heat sealing the tube again with the heat sealing assembly to provide a first seal across the tube and a simultaneous cut therethrough so that a pillow shaped pouch is formed, a second seal being provided simultaneously by the heat sealing assembly, which is in close proximity to the top seal of the pouch and extends inwardly from the adjacent side edge of the pouch, thereby providing a tear line for opening the pouch.

[0014] In another aspect there is provided a heat sealing assembly for use in a vertical form, fill and seal apparatus for making flowable material filled pouches, the assembly being adapted for sealing a thermoplastic film together to form a tube which is filled with the flowable material and sealed and cut into pouches containing such material, which assembly comprises a transversely oriented jaw and a vertically oriented jaw, the vertically oriented jaw being adapted to seal edges of the film with a fin seal or an overlap seal, the horizontal jaw being adapted for transverse motion and to collapse the tubular film and to allow the tubular film when filled with flowable material to pass between its members, which cut and seal the tubular film to form pouches, the vertically oriented jaw having an electrical impulse heat sealing element arranged vertically in a member thereof and being about the length of a pouch, the transversely oriented jaw having an electrical impulse heat sealing and cutting element and being about the width of a pouch, so as to cut and seal the collapsed and filled tubular film, whereby the seal formed provides a bottom closure for an upper pouch and a top closure for a bottom pouch, and providing at least one tear line for opening the pouch by providing at least one of the members of at least one of the jaws with a second electrical impulse sealing element arranged in the member so that at least one second seal is simultaneously formed that extends from one edge of the pouch and for a short distance towards the interior of the pouch to form the at least one tear line or an additional sealing jaw is provided which acts simultaneously with the transverse or vertical jaw to provide the at least one tear line.

[0015] The second seal formed in the pouch may take any suitable shape such as curved or straight, although a straight line is illustrated in the example of this invention produced. Obviously, a shape that directs the tear so that a corner of the pouch is removed would be most desirable. The angle of this second seal relative to the first seal may be varied in a suitable manner. Thus, the two seals may be spaced and parallel, or the second seal may extend from the outer edge towards the sealed edge.

[0016] It is also possible to form a second seal in the vertical seal. For example, a satellite sealing mechanism can be associated with the vertical seal jaws in somewhat the same manner as the above embodiment is associated with the horizontal jaw. A short auxiliary seal can be formed in the machine direction at the opposite side of the pouch to the vertical fin seal.. This short seal would be in the horizontal jaw area so that it would be cut in two by the horizontal seal. An easy tear notch would be created in the pouch above and below the horizontal seal. Thus each pouch would have two tear off notches.

[0017] Other locations for the second seal are possible as long as a suitable tear is produced that opens the pouch in a manner that allows the contents to be dispensed or consumed. The corner being removed represents an example of a suitable result.

Pouch Film

[0018] Many types of films can be used to manufacture the pouches of the present invention. Generally these films must be capable of self-sealing and processing through the vertical form, fill and seal equipment. They should be stiff enough and strong enough for the proposed packaging applications. The nature of the packaging application determines the film selection and the person skilled in the art would be capable of readily selecting a suitable film for the desired purpose. Examples of suitable films include any synthetic thermoplastic polymeric film which meets the above-mentioned criteria. For example, PCT Application WO 99/06476 discloses polymer films made from a homogeneously branched linear ethylene interpolymer film which may be a two-layer or a three-layer coextruded film containing at least one seal layer of a homogeneously branched linear polyethylene. In PCT Application WO 98/50230 there is described a heat sealable multilayer film comprising about 10% by volume of the overall film structure made from an ethylene-styrene copolymer obtained using a single-site catalyst polymerization process and one or more layers comprising: at least one interpolymer selected from interpolymers of ethylene and one or more C₃-C₂₀ α-olefins made by polymerization processes using single-site catalyst, non single-site catalyst and mixtures of such catalysts, and blends thereof. The films may contain a barrier layer selected from nylon polymers, polyethylene terephthalate polymers, amorphous nylon or ethylene vinyl alcohol. An additional tie layer may be present and can be selected from ethylene vinyl acetate polymer, ethylene acid copolymers, ionomers or anhydride functionalized ethylene copolymers. And all of these may be combined with at least one high pressure ethylene homopolymer. Other examples of suitable films are described in the following additional references: WO 98/34844, WO 98/29249, WO 97/20693, WO 97/12755, WO 95/21743, WO 95/10566, WO 95/00587, the disclosures of which are incorporated herein by reference. These are merely representative examples of thermoplastic films and the invention is not to be limited in any way with respect to the film selected for manufacture of the pouch of the invention.

[0019] The heat-sealing assembly of the invention is for use on vertical form, fill, seal machines. Examples of how the assembly is mounted in such a machine may be found in EP 0573447B1, US 2001/10032710A1 and US 5,538,590, the disclosures of which are incorporated herein by reference. A variety of these machines are known to be commercially available and included, but not limited to, are machines manufactured and sold by Prepac, Thimmonier, Inpaco and Elecster. An early patent granted to Prepac for such a machine is U.S. Patent No. 3,886,714, the disclosures of which are incorporated herein by reference. The heat seal assembly can be mounted in the standard jaws of the vertical form, fill, seal apparatus in a manner as would be apparent to a person skilled in the art.

[0020] The process of the invention is well known except for the aspect provided by the second seal described above which offers an easy open feature for a filled pouch.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the accompanying drawings which are used to illustrate the present invention, a typical embodiment of the present invention is described. The invention is not to be limited to this embodiment as the embodiment is included for purposes of illustration only.

Figure 1 illustrates the components of a heat seal assembly for a vertical form, fill and seal machine according to the present invention, which allows for an arrangement that provides an auxiliary seal in the general direction transverse to machine direction;

Figure 2 illustrates the same components found in Figure 1 from the opposite direction;

Figure 3 illustrates a series of pouches of the present invention made on the arrangement of Figures 1 and 2, which demonstrate the tear open feature;

Figure 4 is a schematic perspective view of an arrangement that illustrates another embodiment of the invention wherein a second seal can be created in the machine direction of a pouch;

Figure 5 illustrates a pouch made on the arrangement of Figure 4; and

Figures 6 and 7 illustrate two alternative positions of a second seal on a pouch which seal is created in the machine direction.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Referring first to Figure 1, there are shown the components of a heat sealing element of the present invention. The element is shown generally at 10. The element 10 comprises a backup support 11, a backup rubber 17 and a main sealing element 18. In Figure 1, first and second seal reliefs 13 and 14, respectively, can be seen. In this form of the invention, the seals 13 and 14 are parallel one to the other, although the second short seal 14 can take other shapes and directions as described earlier. The main element 18 includes heating element 12.

[0023] Referring now to Figure 2, one can see the opposite view of the sealing element assembly to that of Figure 1. Thus on the main element 18, the first and second seal impressions which are created in the pouches as they are sealed in the process of manufacture are clearly shown at 15 and 16. When the heat seal assembly is installed in a vertical form, fill, seal machine, the backup rubber 17 and backup support 11 are located on one jaw while the main element containing the heating element is located on the other jaw.

[0024] Referring now to Figure 3, a pouch 20 manufactured according to the process of the present invention is illustrated. The top seal 22 and bottom seal 25 can be seen as well as the vertical seal 23. The second seal is clearly shown in the top pouch of the Figure and the three other pouches in descending order illustrate the tearing of corner 24 of the pouch to create an opening 24a in the pouch for dispensing or accessing the packaged contents.

[0025] Referring now to Figure 4, there is illustrated schematically a fill tube 30 inside a film tube 31 which is meant to be fin sealed at its side edge 33. Sealing bar 32 which represents a portion of a sealing device (not shown), is arranged in the machine direction or vertical direction and is meant to be provided with two sealing elements 15 and 16 as seen in the heat sealing element 18 shown in Figure 2.

[0026] Figure 5 illustrates a pouch shown generally at 40 made using the arrangement of Figure 4. Pouch 40 is made from a film tube 41 which is formed by making a fin, side or vertical side seal 43. A short seal 42 is formed in the pouch 40, adjacent seal 43. In this case, seal 42 is shown to be spaced from and parallel to seal 43. It should be noted that sealing bar 32 may be formed and positioned such that the short seal 42 is formed in pouch 40 so that it extends through two pouches 40. In such instance, each pouch 40 would have a short seal 42 at either transverse edge 44 and hence could be torn open using either seal 42.

[0027] Figures 6 and 7 illustrate pouches shown generally at 40, with like numerals identifying like elements. The pouch of Figure 6 shows a single second seal 42 made by a satellite second sealing element (not shown) that is made in edge 45 which is opposite a fin seal 43 formed in pouch 40. The second seal 42 may be formed at the top and bottom edges (44) of pouch 40, depending on how the satellite second sealing element is positioned.

[0028] The invention may be varied in any number of ways as would be apparent to a person skilled in the art and all obvious equivalents and the like are meant to fall within the scope of this description and claims. The description is meant to serve as a guide to interpret the claims and not to limit them unnecessarily.

Claims

1. A pouch for containing a flowable material manufactured in a vertical form, fill and seal process wherein a pouch is formed from a sheet of thermoplastic film and a transverse heat seal formed between pouches as they are filled serves as a top closure for a lower pouch and a bottom closure for an upper pouch, wherein the pouch is provided with an easy open feature just above or below a respective closure, which comprises a second seal formed between two layers of film in a portion of an edge of the pouch that is in close proximity to and extends inwardly from a corner of the pouch to provide a tear line to open the pouch.

2. A heat sealing assembly for use in a vertical form, fill and seal apparatus for sealing at least two layers of thermoplastic film together, comprising a first jaw and a second jaw, a first and a second electrical impulse heat sealing element mounted on the first jaw, at least one of said jaws being capable of transverse motion and adapted to collapse a tubular film made from said thermoplastic film and to allow the film to pass between said jaws, the first electrical impulse heat sealing element being about the length of the width of the collapsed tubular film so that the flattened tube can be sealed and cut, and the second electrical impulse heat sealing element mounted on the first jaw being in close proximity to the first element and arranged so that the seal it creates extends from one edge of the collapsed tube for a short distance towards the interior of the tube so that a second seal can be made in the tube to provide a tear line for opening the pouch.

3. A process for manufacturing a pouch for containing a flowable material which comprises forming a thermoplastic film into a film tube by forming a vertical fin seal or lap seal in the tube, drawing the tube through a heat sealing assembly of a vertical form, fill and seal apparatus, collapsing the tube, forming a first transverse seal in the tube, continuously filling the tube with a flowable material, allowing the filled tube to drop down a predetermined distance from the heat sealing assembly, collapsing the filled tube and heat sealing the tube again with the heat sealing assembly to provide a first seal across the tube and a simultaneous cut therethrough so that a pillow shaped pouch is formed, a second seal being provided simultaneously by the heat sealing assembly, which is in close proximity to the top seal of the pouch and extends inwardly from the adjacent side edge of the pouch, thereby providing a tear line for opening the pouch.

4. A heat sealing assembly for use in a vertical form, fill and seal apparatus for making flowable material filled pouches, the assembly being adapted for sealing a thermoplastic film together to form a tube which is filled with the flowable material and sealed and cut into pouches containing such material, which assembly comprises a transversely oriented jaw and a vertically oriented jaw, the vertically oriented jaw being adapted to seal edges of the film with a fin seal or an overlap seal, the horizontal jaw being adapted for transverse motion and to collapse the tubular film and to allow the tubular film when filled with flowable material to pass between its members, which cut and seal the tubular film to form pouches, the vertically oriented jaw having an electrical impulse heat sealing element arranged vertically in a member thereof and being about the length of a pouch, the transversely oriented jaw having an electrical impulse heat sealing and cutting element and being about the width of a pouch, so as to cut and seal the collapsed and filled tubular film, whereby the seal formed provides a bottom closure for an upper pouch and a top closure for a bottom pouch, and providing at least one tear line for opening the pouch by providing at least one of the members of at least one of the jaws with a second electrical impulse sealing element arranged in the member so that at least one second seal is simultaneously formed that extends from one edge of the pouch and for a short distance towards the interior of the pouch to form the at least one tear line or an additional sealing jaw is provided which acts simultaneously with the transverse or vertical jaw to provide the at least one tear line.

Drawing