MXPA05012390A

MXPA05012390A - Tear open pouch.

Info

Publication number: MXPA05012390A
Application number: MXPA05012390A
Authority: MX
Inventors: Alan K Breck
Original assignee: Liqui Box Canada Inc
Priority date: 2004-11-16
Filing date: 2005-11-16
Publication date: 2006-05-25
Also published as: EP1666361A1; BRPI0506080A; CA2497718A1; US20060110081A1

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

DEFLECTION OPENING BAG Field of the invention The present invention relates to a bag for containing flowable materials which is easy to open by peeling, to a heat sealing assembly for a vertical form, a filling and sealing machine to be used in manufacturing the bag, and a process to manufacture the bag.

BACKGROUND OF THE INVENTION The packing bags are typically made in vertical filling and sealing machines. Using this machine, a flat continuous ribbon 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 flap seal or seal. fin. The tube formed in this way is pulled vertically down to a filling station. The tube is then collapsed through a cross section of the tube, the position of the cross section being in a sealing device below the filling station. A transverse heat seal is made by the sealing device in the collapsed portion of the tube, then making an air tight seal through the REF. : 168385 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 packed, for example a liquid, is made to enter the filling station, and to fill the tube upwards from the cross seal mentioned above. The tube is then made to move down at a predetermined distance. This movement can be under the influence of the weight of the material in the tube, or it can be caused by pulling or mechanically pushing the tube. The jaws of the sealing device close again, thus collapsing the tube in a second cross section. The second cross section may be above, usually just above the air / material interface in the tube, or the second cross section may be below the air / material interface. The sealing device seals and cuts the tube transversely in the second transverse direction. The portion filled with tube material is now in the form of a pillow-shaped bag. In this way, the sealing device has sealed the upper part of the bag filled and sealed the bottom of the bag that will be formed afterwards, all in one operation. The filling of the product can be conducted on a continuous or intermittent basis. One of these vertical form filling and sealing machines of the type described above is sold under the trade name PREPAC. Other suitable machines are sold under the trademarks INPACO and ELECSTER. There are other types of machines in which the sealing device does not cut the tube in the second cross section, but cuts the tube subsequently. To pack certain materials that can flow but are viscous, it is usually desirable to heat the material. When this is the case, the packaging process is commonly referred to as a hot filling process. A variety of materials that can flow can be packed in this way, for example, milk, syrups, sauces, juices, water and the like. The term "material that can flow" attempts to encompass materials that can flow under gravity or that can be pumped. These materials may include emulsions, pastes, peanut butter, preservatives, dough, ground meat, powders, detergents, oils and granulated solids. It is anticipated that this bag can be used to contain materials that can flow, in particular foods that are packaged under sterile, pasteurized or aseptic conditions. The bags produced through this type of process can be manufactured to contain any volume of material that can flow. In the situation where beverage fluids are packaged in this way, a typical size could be 250 mis or 500 mis. In such a case, it is possible to consume the fluid directly from the bag. Thus, providing a bag that includes an easy peel opening for this purpose is desirable since it avoids the need to use an implement such as a knife or scissors. In addition, since these packages try to be single-use packaging, it is appropriate that the way in which they are manufactured be as economical as possible, without sacrificing the basic packaging requirements for the materials in question. There are many advantages to the present invention such as the economical single stage manufacturing process, and the lack of any requirement for a cutting device of any kind, either in the manufacture or opening of the bag. Many solutions have been proposed to produce packages of this type, and typically these packages have included a notch or detachment line which allows the package to be opened. Examples of the solutions offered include those found in the U.S. patent. No. 3,759,439, issued September 18, 1973 to Cross et al., Patent of E.U.A. No. 4,176,567, issued December 4, 1979 to eisberg, patent of E.U.A. No. 4,890,744, issued on January 2, 1990 to Lane, Jr. et al. and patent of E.U.A. No. 5,470,419, issued November 28, 1995 to Sasaki et al. These structures typically include providing a notch or detachment line in the sealed area of the bag or by other means, such as those found in U.S. Pat. No. 5,470,419 which provides strings in the plastic film when made by melt extrusion. Another solution is found in the patent of E.U.A. No. 4,176,567, in which a sealed marginal portion of a flat bag is perforated by a unique tool head having a tapered and faceted tool head. The tapered and faceted tool head is preferably provided with three and, in any case, not too many facets that produce a corresponding number of straight and longitudinally extending bag cutting edges converging to a point of bag punching at the end. of the tool head. Thus, the process of the present requires an additional step after the bag has been manufactured and the sealed contents, as well as the use of the tool that is designed to pierce the sealed area of the bag. Another example is found in the patent of E.U.A. No. 3,759,439 mentioned above, which includes a flexible reinforcement having a highly localized weakness line, the reinforcement being attached to the surface of the film or incorporated partially or completely within its thickness. Again a complicated solution that could involve additional costs in the manufacture of the packaged product. Reference can also be made to the patent of E.U.A. No. 5,038,550 which describes sealing the edge of a bag with a semicircular heat seal with a groove therein. See figure 11 of this patent. The groove in this case is cut at the edge of the bag and has an insulating seal closely around it, and then a contoured seal further away. Thus, there is a need to produce an easy-open bag for packaging purposes that is simple in design and easy and inexpensive to manufacture.

BRIEF DESCRIPTION OF THE INVENTION The present invention intends to provide a bag that can be easily opened by peeling which can be manufactured using a vertical filling and sealing apparatus that allows the formation of a peel line simultaneously with the sealing of the bag. . Thus, the present invention provides in one aspect a bag for containing a flowable material made in a vertical filling and sealing process wherein a bag is formed from a sheet of thermoplastic film and a heat seal cross formed between bags. while these are filled it serves as a top closure for a lower bag and a lower closure for an upper bag, wherein the bag is provided with an easy opening feature just before or under a respective closure, which comprises a second formed seal between two layers of film in a portion of an edge of the bag that is in close proximity to and extends inwardly from a corner of the bag to provide a detachment line to open the bag. In another aspect, the invention provides a heat seal assembly for use in a vertical form fill and seal machine for sealing at least two layers of thermoplastic film together, comprising a first jaw and a second jaw, a first and a second jaw. second heat sealing elements are electrical pulses mounted on the first jaw, at least one of the jaws is capable of transverse movement and is adapted to collapse a tubular film made from the thermoplastic film and to allow the film to pass between the jaws, the first heat sealing element by electrical impulses has approximately the length of the width of the tubular film collapsed in such a way that the flattened tube can be sealed and cut, and the second heat sealing element with electric impulses mounted on the first jaw is in close proximity to the first element and arranged in such a way that the seal It is believed to extend from one edge of the collapsed tube for a short distance into the tube so that a second seal can be made in the tube to provide a detachment line to open the bag. In yet another aspect, the invention provides a method for manufacturing a bag for containing a flowable material, comprising forming a thermoplastic film in a film tube by forming a flap seal or vertical flap seal in the tube, stretching the tube through a heat seal assembly of a vertical filling and sealing apparatus, collapse the tube, form a first transverse seal in the tube, continuously fill the tube with a material that can flow, allow the tube to fill drop down to a predetermined distance from the heat seal assembly, collapse the filled tube and heat seal the tube again with the heat seal assembly to provide a first seal through the tube and a simultaneous cut through the tube. In such a way that a pillow bag is formed, a second seal is provided simultaneously by the heat sealing assembly, which is in close proximity to the the upper seal of the bag and extends inward from the adjacent lateral edge of the bag, thereby providing a detachment line to open the bag. In another aspect a heat sealing assembly is provided for use in a vertical filling and sealing apparatus for making pouches filled with flowable material, the assembly is adapted to seal a thermoplastic film together to form a tube that is filled With the material that can flow and seal and cut into bags containing this material, the assembly comprises a transversely oriented jaw and a vertically oriented jaw, the vertically oriented jaw is adapted to seal edges of the film with a flap seal or a flap seal, the horizontal jaw is adapted for transverse movement and to collapse the tubular film and allow the tubular film to be filled with material which can flow pass between its members, which cut and seal the tubular film to form bags, the vertically oriented jaw has a heat-sealing element by electric impulses arranged vertically in a member thereof and having approximately the length of a bag, the transversely oriented jaw has a sealing and heat cutting element by electrical impulses and having approximately the width of a bag, in order to thereby cut and seal the collapsed and filled tubular film, whereby the seal formed provides a bottom closure for a top bag and a top closure for a bottom bag, and provide po at least one detachment line for opening the bag by providing at least one of the members of at least one of the jaws with a second electric pulse sealing element disposed in the element such that at least one second seal is simultaneously form which extends from one edge of the bag and for a short distance into the bag to form the at least one detachment line or an additional sealing jaw is provided which simultaneously acts with the transverse jaw or vertical to provide the at least one detachment line. The second seal formed in the bag can have any suitable shape, such as a curve or straight, although a straight line is illustrated in the example of this invention produced. Obviously, a form that directs the detachment in such a way that a corner of the bag is removed would be the most desirable. The angle of this second seal in relation to the first seal can be varied in a suitable manner. Thus, the two seals can be separated and parallel, or the second seal can extend from the outer edge towards the sealed edge. It is also possible to form a second seal on the vertical seal. For example, a satellite sealing mechanism may be associated with the vertical seal jaws in some way in the same manner as the previous mode is associated with the horizontal jaw. A short auxiliary seal can be formed in the machine direction on the opposite side of the bag to the vertical fin seal. This short seal would be in the horizontal jaw area in such a way that it could be cut in two by the horizontal seal. An easy detachment notch would be created in the bag above and below the horizontal seal. Thus, each bag would have two detachment notches. Other locations for the second seal are possible as long as a proper detachment occurs that opens the bag in a way that allows the contents to be supplied or consumed. The corner that is being removed represents an example of an appropriate result.

Film of the bag Many types of films can be used to manufacture the bags of the present invention. Generally these films must be capable of self-sealing and processing through the vertical filling and sealing equipment. They must be rigid and strong enough for the proposed packaging applications. The nature of the packaging application determines the selection of the film and the person skilled in the art would be able to easily select a suitable film for the desired purpose. Examples of suitable films include any thermoplastic polymer film that meets the criteria mentioned above. For example, PCT application O 99/06476 discloses polymeric films made from homogeneously branched linear ethylene interpolymer film which may be a two-layer or three-layer coextruded film comprising at least one film layer. seal of a homogeneously branched linear polyethylene. In the PCT application WO 98/50230 a heat-sealable multi-layer film comprising about 10% by volume of the complete structure of the film made from an ethylene-styrene copolymer obtained using a polymerization process is described. with a single site catalyst and one or more layers comprising: at least one interpolymer selected from interpolymers of ethylene and one or more C3_C2 o-olefins made by polymerization processes using a single site catalyst, catalyst which is not a single site and mixtures of these catalysts and mixtures thereof. The films may contain a barrier layer selected from nylon polymers, polyethylene terephthalate polymers, amorphous nylon or ethylene vinyl alcohol. In addition, an additional fixing layer may be present and may be selected from ethylene vinyl acetate polymer, ethylenic acid copolymers, ionomers or functionalized anhydride with ethylene copolymers. All of these can 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, whose descriptions they are incorporated herein by way of reference. These are merely representative examples of thermoplastic films and the invention should not be limited in any way with respect to the film selected to manufacture the bag of the invention. The heat sealing assembly of the invention is for use in vertical filling and sealing machines. Examples of how the assembly is mounted on this machine can be found in EP 0573447B1, US 2001 / 10032710A1 and US 5,538,590, the descriptions of which are incorporated herein by reference. A variety of these machines are known as being commercially available and include, but are not limited to, machines manufactured and sold by Prepac, Thimmonier, Inpaco and Eleester. An earlier patent granted to Prepac for this machine is the patent of E.U.A. No. 3,886,714, the descriptions of which are incorporated herein by reference. The heat seal assembly can be mounted on the standard jaws of the sealing and filling apparatus vertically in a manner that would be apparent to a person skilled in the art. The process of the invention is well known except for the aspect provided by the second seal described above, which offers an easy opening feature for a filled bag.

BRIEF DESCRIPTION OF THE FIGURES In the appended figures which are used to illustrate the present invention, a typical embodiment of the present invention is described. The invention should not be limited to this modality since it 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 an arrangement that provides an auxiliary seal in the general direction transverse to the direction of the machine. Figure 2 illustrates the same components of Figure 1 from the opposite direction. Figure 3 illustrates a series of bags of the present invention made on the arrangement of figures 1 and 2, which demonstrate the characteristic of opening by detachment.

Figure 4 is a schematic perspective view of an arrangement illustrating another embodiment of the invention in which a second seal can be created in the machine direction of a bag. Figure 5 illustrates a bag made on the arrangement of Figure 4 and Figures 6 and 7 illustrate two alternative positions of a second seal on a bag whose seal is created in the direction of the machine.

DETAILED DESCRIPTION OF THE INVENTION Referring first to FIG. 1, the components of the heat sealing element of the present invention are shown. The element is generally shown with the number 10. The element 10 comprises a back support 11, a backing rubber 17 and a main sealing element 18. In figure 1, first and second seal relieves 13 and 14, respectively, can be observed In this form of the invention, the seals 13 and 14 are parallel to each other, although the second short seal 14 may have other shapes and directions as described above. The main element 18 includes a heating element 12. Referring now to Figure 2, the opposite view to that of Figure 1 of the sealing element assembly can be observed. Thus, in the main element 18, the first and second seal impressions that are created in the bags while sealed in the manufacturing process are clearly shown with 15 and 16. When the heat seal assembly is installed in a machine filled and sealed vertically, the backing rubber 17 and the back support 11 are located on a jaw while the main element containing the heating element is located on the other jaw. Referring now to Figure 3, a bag 20 made according to the process of the present invention is illustrated. The upper seal 22 and lower seal 25 can be observed, as well as the vertical seal 23. The second seal is clearly shown in the upper bag of the figure and the other three bags in descending order illustrate the detachment of the corner 24 of the bag to create an opening 24a in the bag to supply or access the packaged contents. Referring now to Figure 4, a filling tube is schematically illustrated within a film tube 31 which attempts to be sealed by fins on its side edge 33. The sealing rod 32 which represents a portion of a sealing device ( not shown), is disposed in the machine direction or vertical direction and attempts to be provided with two sealing elements 15 and 16 as seen in the heat sealing element 18 shown in Figure 2. Figure 5 illustrates a bag shown generally with 40 made using the arrangement of FIG. 4. The bag 40 is made of a tube of film 41 that is formed by making a side seal of vertical fin or side 43. A short seal 42 is formed in the bag 40 adjacent to the bag 40. seal 43. In this case, seal 42 is shown as separate from, and parallel to seal 43. It should be noted that sealing rod 32 can be formed and positioned in such a way that short seal 42 is formed in bag 40 for which extends through two bags 40. In such a case, each bag 40 would have a short seal 42 at any transverse edge 44 and therefore would be opened by detachment using any seal 42. Figures 6 and 7 illustrate bags generally shown with 40, with similar numbers identifying like elements. The bag of figure 6 shows a single second seal 42 made by a second satellite sealing element (not shown) that is made on the edge 45 which is opposite a fin seal 43 formed in the bag 40. The second seal 42 can be formed at the upper and lower edges (44) of the bag 40, depending on how the second sealing element is placed by satellite. The invention may be varied in any number of ways as would be apparent to a person skilled in the art and all obvious and similar equivalents are intended to be within the scope of this description and claims. The description is intended to serve as a guide to interpret the claims and not to limit them unnecessarily. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A bag for containing a flowable material manufactured in a vertical filling and sealing process, characterized in that a bag is formed from a sheet of thermoplastic film and a cross-heat seal formed between bags while they are filled serves as an upper closure for a lower bag and a lower closure for an upper bag, wherein the bag is provided with an easy opening feature just above or below a respective closure, which comprises a second seal formed between two film layers in a portion of an edge of the bag that is in close proximity to, and extending inwardly from a corner of the bag to provide a detachment line to open the bag.

2. A heat sealing assembly for use in a vertical sealing and filling apparatus for sealing at least two layers of thermoplastic films together, characterized in that it comprises a first jaw and a second jaw, a first and a second sealing element With heat by electrical impulses mounted on the first jaw, at least one of the jaws is capable of transverse movement and is adapted to collapse a tubular film made from the thermoplastic film, and to allow the film to pass between the jaws, the The first heat sealing element by electric impulses has approximately the length of the width of the collapsed tubular film so that the flattened tube can be sealed and cut, and the second electric pulse heat sealing element mounted on the first jaw is in close proximity proximity to the first element and arranged so that the seal it creates extends from one edge of the tube collapsed for a short distance into the tube so that a second seal can be made in the tube to provide a detachment line to open the bag.

3. A process for manufacturing a bag to contain a flowable material, characterized in that it comprises forming a thermoplastic film in a film tube by forming a flap seal or vertical flap seal in the tube, stretching the tube through a tube. heat seal assembly of a vertical filling and sealing apparatus, collapse the tube, form a first transverse seal in the tube, continuously fill the tube with a material that can flow, allow the filled tube to fall down to a predetermined distance from the heat seal assembly, collapse the filled tube and heat seal the tube again with the heat seal assembly to provide a first seal through the tube and a simultaneous cut through it in such a way that a pillow-shaped bag is formed, a second seal is provided simultaneously by the heat sealing assembly, which is in close proximity to the upper seal of the bag and extends inward from the adjacent side edge of the bag, thereby providing a detachment line to open the bag. . A heat sealing assembly for use in a vertical filling and sealing apparatus for making pouches filled with material that can flow, the assembly is adapted to seal a thermoplastic film together to form a tube that is filled with the material that can be filled. flow and seal and cut into bags containing this material, the assembly characterized in that it comprises a transversely oriented jaw and a vertically oriented jaw, the vertically oriented jaw is adapted to seal edges of the film with a flap seal or a flap seal, the horizontal jaw is adapted for transverse movement and to collapse the tubular film and allow the tubular film when it is filled with material that can flow pass between its members, which cut and seal the tubular film to form bags, the vertically oriented jaw has a heat-sealing element by electric impulses arranged vertically in a member thereof and which is approximately the length of a bag, the transversely oriented jaw has a sealing and heat cutting element by electrical impulses and having approximately the width of a bag, in order to thereby cut and seal the collapsed and filled tubular film, whereby the seal formed provides a lower closure for an upper bag and an upper closure for a lower bag, and providing at least one detachment line for opening the bag by providing at least one of the members of at least one of the jaws with a second electric pulse sealing element disposed on the element in such a way that at least one second seal is formed simultaneously which extends from one edge of the pocket a and for a short distance inwardly of the bag to form the at least one detachment line or an additional sealing jaw is provided which simultaneously acts with the transverse or vertical jaw to provide the at least one detachment line.