WO2004045981A1

WO2004045981A1 - Removable slit cover for flexible plastic containers

Info

Publication number: WO2004045981A1
Application number: PCT/CA2002/001774
Authority: WO
Inventors: Luc Marcel Lafond
Original assignee: Luc Marcel Lafond
Priority date: 2002-11-20
Filing date: 2002-11-20
Publication date: 2004-06-03
Also published as: AU2002342481A1

Abstract

A flexible container (1) is provided with an improved cover (2) forming a seal over a preformed opening (16) in the container (1). The container (1) and cover (2) may be made of plastic film or plastic foil. The cover (2) is secured to the container. One portion of the cover (2) includes a pull tab (7) and also forms a reinforced removable band (34) which is part of the seal. Another portion of the cover forms part of reinforced collar positioned around the preformed opening, opposite the reinforced band. A tear zone follows a line between the reinforced band and the reinforced collar. To open the container (1), the removable portion is pulled by the tab (7), along a line within the tear zone, to separate the seal from the reinforced collar. The collar may be provided with a memory to preferentially close the opening after the container (1) is opened. In some instances, the opening is preformed on the cover (2) and the container wall overlies the opening. A method of making the flexible container is also described.

Description

REMOVABLE SLIT COVER FOR FLEXIBLE PLASTIC CONTAINERS

Field of the Invention

The invention relates to flexible containers, including plastic bags made from flexible plastic film to package beverages, food products, or other fluids, granular solids and other materials.

Background of the Invention

Flexible containers, including plastic bags, are used as containers for various materials, including by way of example, milk, juices, and other beverages, snack foods, and many consumer and industrial products, including granular fertilizers, lawn applications, seed products and pelletized materials. Many of the bags are made of polyethylene film, polypropylene film, plastic foil or other suitable flexible films containing plastic materials.

Flexible plastic bags offer many advantages for packaging a wide variety of materials, including foods and beverages. Flexible plastic bags provide protection against premature spoilage, exposure to moisture or other sources of contamination. Flexible plastic bags also offer many other advantages. They add little weight to the packaged product and in most instances are a low cost alternative to other conventional container materials and products made from rigid materials, such as coated cardboard and glass. One of the disadvantages of conventional flexible plastic bags is that they are often difficult to open. Furthermore, consumers are often faced with particular difficulties or inconvenience associated with finding a specialized cutting tool to create a suitable opening to dispense the packaged commodity. By way of example, prepackaged milk is available in flexible plastic bags that are often difficult to open without a specialized cutting tool, scissors or a blade.

Consumers must locate a clean cutting tool, position it along an edge of the milk bag, and choose a cutting path. While holding the bag or a bag holder with the bag in it, the consumer must then operate the cutting tool 'free hand' to provide a satisfactory opening to dispense the contained milk, preferably without any significant spillage. Unfortunately, conventional plastic milk bags are often slippery and difficult to handle. It may be difficult to locate a suitable cutting tool that may have been misplaced earlier by a child or other member of the household. Once located, it may be particularly difficult to position the cutting tool to cut an opening of optimal size and configuration.

In other instances, flexible plastic bags may be inherently difficult to open. For example, plastic foil bags are commonly used for snack foods, including roasted nuts. Plastic foil bags offer superior strength and barriers against food spoilage and contamination. However, consumers are often faced with problems in opening the flexible bags because the materials are inherently strong and tear resistant. In some instances, where the contents are particularly fragile (by way of example, potato chips, crispy snack foods, cookies and the like) a consumer may incidentally damage some of the contents while struggling to open the flexible plastic bag. By way of another example, granular fertilizers are often sold in relatively large flexible plastic bags containing 10 pounds, 25 pounds or more of granular materials.- Typically, the plastic bags are made of a generally cushion-shaped, elongated tubular construction with welded seals along 3 major edges, namely one longitudinal weld along the length of the bag, and two transverse welds, with one weld at each end of the bag. The size and weight requirements for these bags often dictate that the plastic film used to make the bag must be of a relatively thicker construction (compared to the previous examples for packaged foods or beverages) or other reinforced construction. The generally thicker plastic film used to manufacture the larger bags often leads to pronounced difficulties in opening the bags, particularly when the consumer is unable to locate a cutting blade or suitable tool. It is often particularly difficult for an individual to muster sufficient strength to tear through the plastic film to create a suitable opening in the bag. Even if the individual manages to tear the film without the aid of a cutting tool, the opening is often of an irregular shape and inappropriate size. The illustrated difficulties are even more pronounced for those individuals who may have physical disabilities, muscular or other debilitating conditions limiting their ability to open these flexible bag products.

In other instances, children may require close adult supervision or intervention to open conventional flexible plastic bags.

Summary of the Invention

The present invention provides a method and product for use in the manufacture of flexible containers, including plastic bags. It will be understood by those persons who are skilled in the art that flexible plastic bags include, but are not limited to bags made from flexible polyethylene film, plastic foil, and other suitable plastic films.

In one embodiment, the invention provides a product, which includes a flexible plastic film cover laminated over a predetermined opening in a flexible plastic bag. The plastic cover is made from a flexible plastic film. The cover is not necessarily made from the same film, which may be used, for the main body of the flexible plastic bag.

The plastic cover comprises first and second zones and a tear zone. A first zone of the cover is secured to the main body of the plastic bag, near the periphery of the predetermined opening, to provide a secure seal for the opening. In a preferred embodiment, the first zone is secured by lamination to the body of the bag. In a most preferred embodiment, the first zone of the cover is securely welded to the body of the flexible plastic bag, adjacent to the periphery of the opening.

The second zone of the cover comprises a tear zone adjacent the first zone of the cover. The second zone of the cover is removable from the bag by pulling the cover so that the cover is preferentially torn along the tear zone. The cover may be designed so that the entirety of the second zone is removable from the bag, or in other embodiments, it may be desirable to provide a retainer to inhibit complete removal of the second zone from the bag. A portion of the cover remains securely fixed to the body of the bag. By way of example, the first zone remains securely attached to the bag, near the perimeter of the opening in the bag.

In a preferred embodiment, the cover is secured to the bag, adjacent to a predetermined edge or corner of the bag. For example, in a milk bag of generally rectangular shape, it is preferred to secure an embodiment of the plastic cover in a selected comer of the flexible plastic milk bag. The selected corner is provided with a preformed opening in the bag. The preferred cover is secured to the bag, adjacent the perimeter of the opening. In a preferred embodiment of the improved milk bag, the flexible plastic cover is laminated to the body of the bag by welding. A suitable heated production press clamps and welds the cover to the bag in a continuous production line facility. In particular, the first zone of the cover is secured to the body of the bag, adjacent the perimeter of the opening. The first zone is a sheet of flexible plastic film, which is positioned over a sheet of another flexible film, which forms a wall of the plastic bag. The cover is positioned over the opening of the bag so that the two sheets overlap. The first sheet of film, defining the first zone, is welded to the other sheet of film, which forms part of the body of the flexible plastic bag. The cover is welded to the body of the bag so that the opening is completely sealed. The cover defines a tear zone. The tear zone provides a preferred location for separation of the second zone of the cover from the first zone wherein the latter zone is secured to the body of the milk bag.

In this embodiment, the laminated sheets of the first zone of the cover and the other sheet of film, defining the body of the plastic bag, define a collar of reinforced plastic film which has a nominal thickness greater than either of the individual sheets of plastic film. When the second zone of the cover is torn away from the bag, exposing the opening, the milk may be poured out of the preformed opening. The collar may be formed to provide a spout of predetermined size, shape and orientation. The collar may also be made to open when the bag is tipped to pour milk from the bag. However, the collar may be biased to subsequently return to a closed position when the bag is returned to its upright position. This tendency to self seal may be provided by incorporating a memory into the plastic film during the lamination process.

In another embodiment, the flexible bag comprises a gripping surface to provide a better location for a user to clasp the removable second portion of the cover. The user may clasp the gripping surface between a thumb and at least one other finger, to pull the removable second portion from the flexible plastic bag. The gripping surface may take the form of an embossed tab along one edge of the cover. The embossed tab may be notched at a predetermined location, adjacent the collar, to allow the user to initiate tearing of the cover in a preferred location and direction within the desired tear zone.

In yet another embodiment of the present invention, the cover is used to convey information. By way of example, the information may take the form of a freshness date, product code, promotional material, redeemable coupons, or other suitable information. Complimentary information may appear on the removable portion of the cover and on the portion which remains secured to the plastic bag after the removable portion of the cover is detached. The cover may also be used to support advertising or promotional materials for other products or services. In one embodiment of the method of the invention, a flexible plastic bag is made from a continuous elongated web of plastic film. The film is fed from a source toward a filling station. The film is advanced and then cut or otherwise shaped to pre-form a predetermined opening at a location of predetermined distance from a similar, adjacent preformed opening. The preformed opening is preferably located so that once the bag is completed, filled, sealed and cut, the covered opening will be positioned in a corner of a generally rectangular shaped bag. A pre-shaped cover is laminated to the advancing feed stock by welding the cover over and adjacent the opening. The cover may carry consumer or other information for display with the saleable product. The advancing feed stock is welded into a sleeve which advances to a filling station. The advancing sleeve is closed at one end, further advanced, filled with milk and then sealed at the other end.

The cover is shaped to provide a tear zone within a pre-selected area. In addition, the laminated cover and bag may be provided with an embossed gripping surface, one or more notches as a starting point for opening the filled bag, and a reinforced collar adjacent the predetermined opening which has been sealed by the cover.

There are other embodiments of the invention which will become apparent upon review of the appended drawings and detailed description. In the Drawings

Several embodiments of the present invention are represented in the following drawings.

Fig. 1 is a representation of an embodiment of an improved flexible plastic bag of the present invention, such as a milk bag filled with milk. Fig. 2 is an enlarged representation, in plan view, of a preferred embodiment, showing a cover secured about and over a preformed opening in a corner of the milk bag shown in Fig.1.

Fig. 3 is a partial plan view of a section of flexible plastic film, in which a partial opening is formed. The film is an intermediate product before a cover is secured to a milk bag, to make the product shown in Fig. 2.

Fig.4 is an enlarged representation, in plan view, of another embodiment of the invention, in which another cover is secured over a corner of another milk bag.

Fig. 5 is a partial plan view of a section of flexible plastic film, in which a partial opening is formed. The film is an intermediate product before a cover is secured to a milk bag, to make the product shown in Fig. 4.

Fig. 6 is an enlarged representation, in plan view, of yet another embodiment of the invention, in which another cover is secured over a corner of yet another milk bag. Fig. 7 is a partial plan view of a section of flexible plastic film, in which a partial opening is formed. The film is an intermediate product before a cover is secured to a milk bag, to make the product shown in Fig. 6.

Fig. 8 is a partial plan view of another embodiment of the invention, showing another embodiment of a cover secured about and over a preformed opening in a milk bag.

Fig. 9 is a partial plan view of a section of flexible plastic film, in which an opening is formed. The film is an intermediate product before a cover is secured to a milk bag, to make the product shown in Fig. 8. Fig. 10 is a schematic representation of a continuous feed of flexible plastic film, in a process used to make one embodiment of an improved plastic bag of this invention, filling and closure of the bag, with an improved cover secured over a preformed opening.

Detailed Description of Several Embodiments of the Invention With reference to Figs. 1 , 2 and 3, a preferred embodiment of a flexible container 1 is shown after it has been filled and sealed. Bag 1 is of a general tubular configuration, with lateral seals 3, 4 at opposing ends. A longitudinal seal (not shown) extends along the length of the bag, along the back wall of the bag 1 and is not visible in this frontal view. The bag may be used to package many different materials. The bag is made of flexible material suitable for the particular uses at hand. By way of example, the bag may be of generally plastic construction, laminated plastic materials including plastic foil or other suitable flexible materials. Polypropylene and polyethylene are only two examples of the many flexible plastics commonly used for packaging. However, other materials may also be selected based on material performance, cost, availability and other factors.

The plastic bag of the preferred embodiment is provided with a cover 2 secured about a preformed opening 16 cut in the wall of the bag 1. In this example, the bag is made of a thermoplastic material. The cover 2 is a generally rectangular flap that has been secured to the front and back walls of the bag.

During the manufacturing process, (as shown in the schematic representation of Fig. 10) the bag 1 is made from a web 100 fed continuously from a web source 101. The web is cut to form an opening slit 102. A rectangular cover 106 is laminated over an underlying opening slit of corresponding size and shape, further along the web. A similar cover 108 has been welded over and about yet another corresponding opening slit, further along the advancing web. It will be understood that at this point, the covers 106, 108 are welded to the web such that there are no more than two laminated sheets (namely the web and the film) in any one location, and in some locations beneath the covers, as will be explained further below, the covers are not laminated or welded to the web (bag wall) in certain locations immediately adjacent the corresponding opening slits 102. In other embodiments, which are not shown, it may be desirable to provide openings of different shapes. For example, although the described embodiment features an opening slit, other openings may take the form of slots and cut outs of various shapes. Similarly, the described embodiment refers to a rectangular shaped cover. However, the shape and relative size of the cover may also be varied, according to the requirements for a particular container design.

Each cover is provided for a separate bag that will be filled, sealed and cut from the web, further along in the process. The web is formed into a generally tubular configuration, with a longitudinal weld forming a longitudinal seam 104. The longitudinal, seam 104 corresponds to the juncture where the sides of the web have been welded together to form a seal along the length of the tubular sleeve.

The tubular sleeve is advanced to a filling station (not shown) where the bag 117 (open at its top lateral edge, but sealed at its bottom lateral edge during the sealing and cutting of a previous bag) is filled with the material to be packaged. The bag 115 is shown after it has been filled with the packaged contents and is being sealed along edge 112 in a sealing and cutting press 111. During the sealing process, the cover of bag 115 (positioned with the press and consequently not shown) is further heat pressed to weld the cover and walls of the bag to complete the sealing process about and over the underlying opening slit. This process will be further described with reference, again, to the examples of Figs.2 and 3.

In Fig 3, when the web 30 is advanced through the process, an arcuate opening slit 33 is cut into the flexible web, generally centered about a longitudinal axis 32 of the web. Axis 32 also corresponds to a fold line, along which the tab 7 will be secured to the bag during the manufacturing process. The fold line will also represent the center line for the overlaid cover so that half of the cover will be secured to a front wall of the bag and the other half of the cover will be secured to the opposing back wall of the bag. The slit 33 terminates at ends 37, 37' leaving uncut widths or bands 36, 34 of flexible web between the terminal ends 37, 37' and the lateral line 31. Line 31 represents the expected location of the lateral edge and seam of the bag after it has been filled, sealed and cut.

In Fig. 2, cover 2 is welded to bag 1 such that a tab 7 is provided. The tab 7 may be embossed to enhance a user's ability to grip and tear open the closed bag. Tab 7 comprises two thicknesses of the flexible film from which the cover was initially made. In this example, the thickness of film used to make the cover is equivalent to the thickness of the web used to make the bag. Consequently, the tab 7 will be approximately twice the nominal thickness of one wall of the plastic bag. A notch 8 is provided to direct the user's tearing motion toward an unsealed zone 14, representing a relatively weakened zone, based on shear strength, relative to the immediately surrounding areas on the sealed cover 2. Unsealed zone 14 extends from the tab 7, from a first end 21 to opposite end 22. Although this example features a notch, other techniques or elements may be used. For example, the weakened zone may be provided by an embossed surface groove rather than a cut or notch.

The hatched area 9 represented on the sealed cover corresponds to a reinforced area in which 4 thicknesses of film have been welded together in a laminated array. The reinforced area 9 is bounded along one side by an arcuate edge 24 which is positioned adjacent the precut opening 16 in the bag. The reinforced area 9 is bounded by upper edge 31. The reinforced area 9 extends from the tab 7, through the reinforced band 34 to the right terminal edge 6 of the cover 2. Reinforced band 34 is approximately the width of upper seam 10 of the bag. It will be understood that the upper seam 10 is comprised of two thicknesses of the web used to make the bag, welded together.

The cover 2 is also reinforced in lower zone 11 , an area corresponding to 4 thicknesses of film welded together in a laminated arrangement. The reinforced zone 11 is added to inhibit the formation of a capillary along the vertical intersection line between the tab 7 and the laminated area 5 of the cover. Laminated area 5 corresponds to two thicknesses of film, a first thickness of the bag (one wall), overlaid by the cover and welded together. An additional zone 12 is provided to further inhibit formation of a capillary, by laminating two thicknesses of film, namely two walls of the bag together to add reinforcement along this sector. The laminated area 5 of the cover is bounded by an arc 18 running adjacent to unsealed zone 14, a lower edge 13, reinforced zone 11 , and the right terminal edge 6 of the cover. Since approximately half of the cover also extends to the back wall of the bag, which is not shown, corresponding areas are also provided on the back wall.

In this preferred embodiment, the reinforced areas 9, 11 and additional zone 12 are formed during the sealing step, after the bag is filled, during formation of the upper closing seal 10.

A consumer may take the filled bag and tear open the bag 1 by applying force to the tab 7, adjacent the notch 8, tearing the tab 7. toward and along the weaker (unlaminated) area 14 until a portion of the cover is torn away, leaving reinforced band 34 and upper seal 10 in tact. It will be understood that a reinforced collar is provided by the remaining reinforced band 34, laminated area 5 and reinforced area 12 that remain after the other portion of the cover is torn away along the weaker, unlaminated tear zone 14. A second embodiment of a flexible bag is illustrated in Figs.4 and 5. An intermediate web 50 is shown in Fig. 4. The web 50 of film is ultimately used to make the flexible bag with improved cover 2 shown in Fig.4. Web 50 is cut to remove a cutout portion 56' and provide two arcuate slits defined by sections 53', 53 extending between terminal ends 57, 55 and 55', 57'. To avoid fouling the contents of the finished bag, cutout 56' may be removed by a vacuum stream or in another suitable manner. The opening slits 53', 53 are cut centered about longitudinal axis 52 leaving uncut bands 56, 54 in place. The slits 53', 53 will later define the preformed opening of the bag once it is filled, sealed and cut. After the cover 5 is welded to the bag and completely sealed, as shown in Fig. 4, longitudinal axis 52 will run along the vertical center line of the secured cover.

In the sealed bag 40 shown in Fig. 4, the cover 2 is defined by upper edge 51 , lower edge 13', left edge 52 and opposing right edge 6'. Reinforced zones 9 and 11 are provided, each zone representing a total of four laminated thicknesses, welded together for added strength in their respective areas. The bag 40 is shown with its upper lateral seal 10 extending from reinforced zone 9 and along the upper edge of the bag 40. In this embodiment, reinforced zone 9 is bounded by upper edge 51 , left side 52, edge 41 (which corresponds to the upper edge of zone 42 described below), arcuate edge 24 and the upper most portion of right edge 6'. Reinforced zone 9 includes reinforced band 54, the latter being of the same width as upper seal 10 of the bag.

In this embodiment, a zone 42 is provided in which only two overlying thicknesses of the cover have been welded together since the cutout 56' was removed during the bag manufacturing process. That is, the two thicknesses of film representing the cover are welded together in a two-ply arrangement within this zone, to provide a relatively weaker zone (based on shear strength) compared to the immediately surrounding reinforced, four-ply zones 9 and 11. To inhibit the formation of a capillary near the lower edge of zone 11 , the front and back walls of the bag are welded together to provide laminated zone 12. A notch 43 is provided, partially extending into the two-ply zone 42. The notch 43 is relatively short and extends less than about half way into zone 42. There is a relatively weaker, unlaminated zone extending between the right edge of zone 42, between opposing arcuate sections 24 and 18, and extending up to and terminating at reinforced band 54. Preformed slit 16 remains in the bag so that an opening or spout will be provided when a portion of the cover is later torn away from the bag. By way of example, a consumer wishing to open the bag 40 would grasp the bag in the vicinity of zone 11 , and the reinforced area 9 in the vicinity of edge 41 and then tear most of the upper reinforced portion 9, along the unlaminated zone, and away from the bag 40 and the remaining laminated portion 5 of the cover. After the bag is opened, slit 16 will define the opening or spout of the bag, to allow the contents to be poured out. The resulting spout will have a reinforced collar defined by the portion of the cover that remains secured to the bag, about the periphery of the spout.

In this embodiment, as well as in other embodiments of the present invention, portions of the cover may be used to convey information to consumers or others concerning the product, packaging or other matters. By way of example, the tear away portion of the cover may have proof of purchase information or coupon - like matter printed or embossed onto that portion. It may be useful to imprint important product information on the remaining collar portion of the cover. For example, product batch number information, product code information, and 'best before date' information may be useful in case of product recalls, or to facilitate tracing of particular product batches. The use of the cover portion to convey this information is particularly useful in association with milk packaged in clear plastic bags. For esthetic and other reasons, conventional milk bags are transparent so that all of the contents of the bag will be readily visible. Since the cover of the invention may be adapted to be of a relatively small size compared to a filled milk bag, the cover and related information may be secured to the bag without obscuring the contents of a transparent milk bag.

Figs. 6 and 7 illustrate yet another embodiment of a milk bag made in accordance with the invention. During the manufacturing process, two arcuate slits represented by segments 77, 75 and 75', 77' are cut into the web 70. An uncut segment 76 of the web separates the two arcuate slits. The arcuate slits are centered about center line 72. Once the bag is filled, sealed and cut, this center line will correspond to left edge 72 of the half-portion of cover 2 illustrated in Fig. 6. (It is to be understood that the other portion of cover 2, of similar size and configuration, is secured on the back wall of the bag and is not visible in this frontal view.)

As described in association with Fig. 10, the cover is initially secured to the web so that the two sheets (corresponding to the cover and the bag wall) are welded together in a two-ply arrangement, except for predetermined areas surrounding one or more preformed openings in the bag. In the embodiment of Fig. 6, there is a laminated portion 5 (comprising a corresponding portion of the cover) which is shown generally to the right and below an unlaminated arcuate zone surrounding underlying slit 16. Portion 5 is an area in which the corresponding part of the cover film is welded to an underlying sheet of film of the bag wall, forming a two-ply construction. Portion 5 is bounded by arcuate edge 18 which is set back from slit 16 to avoid accidental sealing of the opening during the manufacturing process. The two-ply portion 5 is also bounded by lower leg 11 of reinforced area 9, and an upper leg of area 9 which extends in line with upper seam 10, parallel to the upper edge 71 of the bag 60.

The unlaminated arcuate zone is bounded by an arcuate edge 24 of the reinforced zone 9, and complimentary arcuate edge 18, extending from terminal ends 22 to the interior edge of reinforced leg 11. Moderately reinforced zone 12 is also provided by laminating the front and back walls of the bag, immediately below the lower edge 13" of the cover.

In this embodiment, a notch 63 is provided adjacent one end of the unlaminated zone surrounding the preformed opening. The cover 2 may be embossed or otherwise treated to improve the gripping surface for tearing open the covered portion of the bag 60. Most of reinforced area 9 is torn away, from the notch, along a line within, or adjacent to, the unlaminated zone, and up through to the upper edge 71 of the bag 60. The remaining portion of the cover defines a reinforced collar extending about the resulting spout. A further embodiment of a milk bag is shown in Figs. 8 and 9. In Fig. 9, a web 90 is cut to provide an inverted triangular opening 94, centered along a fold line 92 corresponding to edge 92' in the sealed bag 80 shown in Fig. 8. Cutout portion 94 from the web is removed and discarded to avoid subsequent fouling of the. packaged contents.

In Fig. 8, cover 2'" is a substantially triangular flexible plastic film that has been welded to the body of the bag 80. Bag 80 has an upper edge 91 running along a welded closing seam 85. Half of the cover 2"' is shown in this frontal view. The other half of the cover 2"' is secured in a like manner to the back wall of the bag 80. The cover is welded to the bag 80 along a reinforced band 81. The band 81 is of a two-ply construction. The band 81 is made by laminating one thickness of film (used to make the cover) over another thickness of film (from the single sheet of web used to make one wall of the bag). At opposing ends of the band 81 , there are two further reinforced zones 11'" and 89 which are formed by laminating four thicknesses of film in overlapping arrangement. In each case, the four thicknesses are made up of two thicknesses of film used to make the cover and two thicknesses of film used to make the bag, for a total of four overlapping, welded thicknesses in these areas. Below reinforced zone 11'", zone 12'" is provided to strengthen the edge of bag 80 along its edge 92'. Tab 7' is formed along two sides of the cover 2"' by folding two overlapping thicknesses of the film and welding those two thicknesses together along a selected area. Tab 7' is provided with indentations 83, 83' as preferential tear points. Tab 7' may be embossed or treated to improve the gripping surface for tearing open the closed bag. The cover also has an unlaminated tear zone 82 wherein the two overlapping thicknesses of film of the cover have not been welded together.

The closed and sealed bag 80 may thereafter be opened by tearing away a portion of the cover from the body of the bag 80, starting from either of notches 83, 83' and tearing toward the other notch. The portion of the cover will tear away along a line within the unlaminated zone 82 and the tearing step may be continued until the portion of the cover is separated from the bag 80. (The tear line will not necessarily follow edge 84.) Once the indicated portion of the cover is torn away, an opening or spout is created in the bag to permit emptying of the packaged contents of the bag. The portion of the cover that remains secured to the bag, including portions within areas 11'", 81 and 89, forms a reinforced collar about the perimeter of the spout. The collar is of relatively thicker construction having at least two thicknesses of overlapping laminated film, compared to the adjoining single sheet of film forming the wall of the bag 80.

In manufacturing the bag, it is possible to provide the collar with a memory so that it will be slightly biased toward maintaining a closed position. When the bag is tipped to empty a portion of the contents through the opening, the collar will tend to open thereby forming a spout. When the bag is returned to its upright position, and the collar is no longer under load from the contents of the bag, the collar will tend to return to its preferred, closed position. Although the closed position will not provide an airtight or fluid tight seal, in most instances the closure will be sufficient to prevent contamination from dust, particles, flying insects and other undesirable matter. It will be particularly desirable to provide a closure of this type for flexible packaging used for picnics, boxed lunches and the like. This closing feature may also be provided in flexible packaging used for non food products.

In some embodiments, it may be desirable to make the cover from a film known to have a particular grain or linearly oriented properties such as tear resistance. For example, a film known to have enhanced tearing properties along a certain axis or grain may be selected to take advantage of those properties. For example, if the film is known to have a certain direction, grain or pattern of alignment, the film may be positioned and secured to the bag such that the resulting tear zone will follow that inherent direction. This pre-determined orientation will enhance easier separation within the tear zone of the second zone from the first zone of the cover. Although the above examples have described embodiments in which the same or comparable materials have been used to make the cover and bag, other embodiments will include a cover made from a film with a thickness differing from the thickness of web film welded to the cover. The film of the web and the film of the cover may vary in terms of relative strength rating so that the second portion of the cover will be easier to tear relative to the nearby 'portions of the body of the bag. The film of the cover may also differ from the web film in other aspects, including quality, color, and composition.

Furthermore, the preferred embodiments refer to securing the cover to the web by welding. However, persons skilled in the art will understand that it will be possible, and in some instances desirable, to secure the cover to the web material by using suitable adhesives or other features or processes.

It will also be apparent to persons skilled in the art that the specific examples of openings described above have been formed by cuts that have pierced through the entire thickness of the web. However, it will be appreciated that it is not necessary to completely pierce a web or film to provide a preformed opening. For example, a deeply embossed groove or segmented cuts may be provided along a desired path.

In other embodiments, it may be desirable to provide a preformed opening on the cover rather than on the web used to make the bag. For example, it may be preferable to provide a cover having a preformed opening overlaid above a fully sealed container such as a bag. For example, in plastic foil bags used for peanuts or other snack foods, it may be impractical to cut a slit or opening in the bag itself, because of additional undesirable tearing, or other problems which may occur while handling a precut plastic foil web. Accordingly, a plastic film of a suitable composition may be used to make the cover with a preformed opening on the cover itself. In that case, the web (or wall) of the bag will itself act as a seal for the opening formed on the cover.

It is also noted that the specific embodiments described above have featured covers that have been positioned on the outsides of the respective bags. However, it will be apparent that the position of the"cover may be altered with relative ease during the manufacturing process. It may, in some instances, be particularly desirable to do so. For example, where the contents of the container will be packaged under pressure, the cover may be secured on the inside of the container to reduce the tendency for delamination of the secured films. In these cases, certain features will be provided on the outer wall of the container (by way of example, the gripping surface) since the cover piece will be located on the inside of the container.

The embodiments described in this specification are merely, illustrative and are not intended to be limited to the specific features, elements pr steps as described herein. Further and other modifications and variations will be apparent to those skilled in the art, thus making it possible to practice the other embodiments of methods and products, all of which are within the spirit and scope of the present invention.

Claims

What is claimed is:

1. A flexible container made from a first flexible film and defined by a first edge, the container comprising:

(a) a cover made from a second flexible film, the cover comprising first and second portions, the first portion of the cover overlapping a first portion of the first flexible film, and either the cover or a second portion of the first flexible film providing a seal for a preformed opening;

(b) the preformed opening being defined by either the first flexible film or the cover, the preformed opening being located adjacent to the first edge;

(c) the first portion of the cover being secured to the first flexible film, and defining a reinforced collar about the preformed opening;

(d) the second portion of the cover defining a tear zone adjacent the first portion of the cover, whereby the second portion of the cover is removable from the first portion of the cover, along a line within the tear zone, to open the seal for the preformed opening.

2. The flexible container claimed in claim 1 , the first portion of the cover is laminated to the first flexible film.

3. The flexible container claimed in claim 2, the second portion of the cover comprising a gripping surface.

4. The flexible container claimed in claim 2, the second portion of the cover comprising a reinforced band opposite the reinforced collar.

5. The flexible container claimed in claim 4, the tear zone located intermediate the reinforced collar and the reinforced band.

6. The flexible container claimed in claim 5, comprising a gripping surface secured to the second portion of the cover.

7. The flexible container claimed in claim 6, the gripping surface comprising a textured finish.

8. The flexible container claimed in claim 7, the gripping surface being supported on a portion of the reinforced band, adjacent to the first portion of the cover.

9. The flexible container claimed in claim 8, one sheet of the first film having a first nominal thickness, and one sheet of the second film have a second nominal thickness differing from the first nominal thickness.

10. The flexible container claimed in claim 9, the nominal thickness of the second film having a nominal thickness less than the nominal thickness of the first film.

11. The flexible container claimed in claim 8, one thickness of the first film having a first nominal tear strength, and one thickness of the second film have a second nominal tear strength differing from the first nominal tear strength.

12. The flexible container claimed in claim 11 , the nominal tear strength of the second film having a nominal tear strength less than the nominal tear strength of the first film.

13. The flexible container claimed in claim 12, the container defining a second edge intersecting with the first edge, the tear zone defining a band of predetermined shape extending between the first edge and the second edge of the container.

14. The flexible container claimed in claim 13, the reinforced collar operating between a first open position and a second closed position.

15. The flexible container claimed in claim 14, the reinforced collar being biased for movement from the open position to the closed position.

16. The flexible container claimed in claim 15, the cover supporting information on one or both of the first and second portions of the cover.

17. The flexible container claimed in claim 13, the cover being made from a . film having a linear grain defining a direction of decreased resistance to tearing, the grain being aligned with the tear zone.

18. The flexible container claimed in claim 6, the first film made from a first plastic film having a first nominal tear strength, the second film being made from a second plastic film having a second nominal tear strength, the nominal tear strength of the second film being less than the nominal tear strength of the first film.

19. A method of making a flexible container of generally tubular construction and of a predetermined length from a flexible web, the flexible web defining a first sealed transverse edge, and a second sealed transverse edge spaced apart from the first sealed edge by the predetermined length, the method comprising: pre-forming an opening on either the flexible web or on a cover made from a flexible film, adjacent the first edge; securing a first portion of the cover to the web, the first portion being secured to the web along a collar located adjacent to a first side and about the preformed opening; reinforcing the collar by laminating the first portion of the cover to the web; forming a removable seal from a second portion of the cover or from a portion of the flexible web to enclose the preformed opening; forming a reinforced band comprising the second portion of the cover, in opposing relation to the reinforced collar; and providing a tear zone in the second portion of the cover, intermediate of reinforced band and the reinforced collar.

20. The method of claim 19, comprising: forming the reinforced band by laminating a first thickness of the flexible film above a second thickness of the flexible film.

21. The method of claim 20, comprising: forming the reinforced band by laminating two thicknesses of the flexible web with the first and second thicknesses of the flexible film.

22. The method of claim 21 comprising, providing a textured gripping surface adjacent the tear zone.

23. The method of claim 22 comprising, providing a weakened zone along a portion of the gripping surface, aligned with and spaced apart from the tear zone.

24. The method of claim 23 comprising, providing the textured gripping surface on the second portion of the cover.