Patent application title: FLEXIBLE FILM PLATE-MAT BAG
Eric Henderson (Dallas, TX, US)
John Michels (Highland Village, TX, US)
Joe Sagel (Plano, TX, US)
IPC8 Class: AB65D3316FI
Class name: Flexible bags bag closure secured by a releasable or frangible bond (e.g., peel seal)
Publication date: 2009-06-25
Patent application number: 20090161995
A method for forming a plate-mat bag using a form, fill, and seal machine
and the resultant bag. The film used to form the bag is oriented so that
the product side layer is not a critical barrier layer. The top most
portion of the bag is unsealed forming a tab. Below the top most portion,
a peelable upper seal is utilized so that a consumer can destroy the
upper seal using the tab and tear open the bag along slits made in the
product side layer. This results in an easy open package which when
opened can serve as a plate.
1. A package comprising a flexible film, said package comprising:a bottom
seal;an upper peelable seal comprising a force distributing
configuration, wherein said upper peelable seal has a seal area of a
defined width and length;a front panel defined as between said bottom and
upper seals, wherein said front panel has a right side and a left side;a
back panel contiguous with said front panel and defined as between said
bottom and upper seal;wherein said front and back panels each comprise at
least two layers of film, an inner and an outer layer;wherein said inner
layer comprises at least two score lines running from the upper seal and
the bottom seal; andwherein said package comprises an extension of the
package film above the upper seal.
2. The package of claim 1 wherein said outer layer comprises oriented film.
3. The package of claim 2 wherein said orientation is aligned with said score lines.
4. The package of claim 1 wherein said outer layer comprises barrier properties.
5. The package of claim 4 wherein said outer layer comprises a metalized film.
6. The package of claim 1 wherein said upper seal comprises a tip, and wherein the seal area at said tip is narrower than the width of the seal area along the rest of said seal.
7. The package of claim 1 wherein the seal area of said upper seal has a width of between about 1/16.sup.th to about 1/8.sup.th of an inch.
8. The package of claim 1 wherein said upper seal comprises a chevron shaped seal.
9. The package of claim 1 wherein said extension of the package film above the upper seal further comprises two cuts in said front panel thereby forming a tear tab.
10. The package of claim 1 wherein said at least two score lines comprise at least one score line vertically oriented on a left side of said front panel, and wherein at least two score lines further comprise at least one score line vertically oriented on a right side of said front panel.
11. The package of claim 1 wherein said upper peelable seal comprises resin.
12. The package of claim 1 wherein said upper peelable seal comprises a cold seal.
13. The package of claim 1 wherein said upper peelable seal comprises a line seal.
14. A method for making a flexible film package said method comprising the steps of:a) obtaining a flexible film web having a layer comprising at least two vertical score lines, wherein at least one layer within said flexible film is oriented to preferentially tear in the direction of said at least two score lines;b) feeding said flexible film into a form, fill, and seal machine such that said at least two score lines are parallel to the direction of film travel;c) forming said flexible film web into a tube;d) sealing said flexible film web at the bottom of said tube, thereby forming a bottom seal on a resultant package;e) filling said resultant package with product; andf) sealing at the top of a resultant package a force distributing peelable seal wherein film material extends beyond said seal, and wherein said seal has a seal area of a defined width and length.
15. The method of claim 14 further comprising the step of:g) cutting said film material extending beyond said seal to form a tear tab.
16. The method of claim 14 wherein said sealing step f) comprises sealing at the top of a resultant package a chevron shaped seal.
17. The method of claim 14 wherein said sealing step f) comprises sealing at the top of a resultant package a seal, wherein the seal area of said seal has a width of between about 1/16.sup.th to about 1/8.sup.th of an inch.
18. The method of claim 14 wherein said sealing step f) comprises sealing at the top of a resultant package a seal, wherein said seal comprises a tip, and wherein the seal area at said tip is narrower than the width of the seal area along the rest of said seal.
19. The method of claim 14 wherein said obtaining step a) comprises obtaining a layer of oriented polypropylene.
20. The method of claim 14 wherein said filling step e) comprises filling said resultant package with a snack food.
21. The method of claim 14 wherein said feeding step b) comprises feeding said flexible film into a vertical form, fill, and seal machine.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an easy to open package, designed in a plate-mat bag configuration, and a method for making same. When the package of the present invention is opened it forms a plate which the consumer can set on a surface and consume the packaged contents. Several features of one end of the package provide for easy opening of the package by a consumer.
2. Description of Related Art
Snack foods and other items are often packaged in bags formed from thin, flexible packaging films. These thin films are formed primarily of plastics, such as polypropylene and polyethylene, but can also contain metalized films, foil, paper, or oriented films. These packaging films can have numerous layers directed to achieving specific needs, but are generally formed at least in part by extrusion of a plastic layer, co-extrusion of multiple layers simultaneously, extrusion coating of another material (such as paper), and the lamination of two layers together via either extrusion lamination or adhesive lamination. In the discussions below, both extrusion lamination and adhesive lamination processes are discussed in more detail, but it is noted that any designated layer that is fed into these two processes can already be a multi-layer film formed by any of the above processes.
An exemplary film 100 for packaging of food products is seen in FIG. 1. The outermost layer 102 is an OPP layer, short for oriented polypropylene, while the innermost layer 106 is a metalized OPP or other barrier material. An oriented polymer material has been specially treated so that the long polymeric molecules tend to align in a given direction, causing the material to preferentially tear in that direction. Sandwiched between the two OPP layers 102, 106 is an adhesive such as polyethylene 104 or other adhesive. Printing for the package is done on the inside of the outer layer and becomes sandwiched between the middle and outer layers. The innermost, metallic layer 106 can itself be a layered laminate and contains a sealant layer 108 on what will be the inside, or product side, of the package. This sealant layer 108 is typically formed of a ter-polymer, composed of ethylene, propylene, and butylenes, along with the metallic layers, and provides a barrier to retain taste and freshness of the product contained therein. Other materials used in packaging are polyester, paper, polyolefin extrusions, adhesive laminates, and other such materials, or a layered combination of the above.
Once the material is formed and cut into desired widths, it can be loaded into a vertical form, fill, and seal machine to be used in packaging the many products that are packaged using this method. FIG. 2 shows an exemplary vertical form, fill, and seal machine that can be used to package snack foods, such as chips. This drawing is simplified, and does not show the cabinet and support structures that typically surround such a machine, but it demonstrates the working of the machine well. Packaging film 210 is taken from a roll 212 of film and passed through tensioners 214 that keep it taut. The film then passes over a former 216 which directs the film as it forms a vertical tube around a product delivery cylinder 218. This product delivery cylinder 218 normally has either a round or a somewhat oval cross-section. As the tube of packaging material is pulled downward by drive belts 220, the edges of the film are sealed along its length by a vertical sealer 222, forming a back seal 224. The machine then applies a pair of heat-sealing jaws 226 and accompanying jaw face 233 against the tube to form a transverse seal 228. Different shapes of jaw faces 233 result in different shaped seals. The transverse seal 228 acts as the top seal on the bag 230 below the sealing jaws 226 and the bottom seal on the bag 232 being filled and formed above the jaws 226. After the transverse seal 228 has been formed, a cut is made across the sealed area to separate the finished bag 230 below the seal 228 from the partially completed bag 232 above the seal. The film tube is then pushed downward to draw out another package length. Before the sealing jaws form each transverse seal, the product to be packaged is dropped through the product delivery cylinder 218 and is held within the tube above the transverse seal 228.
The form, fill, and seal machines are quite expensive, in the range of $250,000 each, but pay for themselves easily when compared to the cost of pre-formed bags and the machinery to fill them. However, in order to maximize the productivity of the form, fill, and seal machines, it is common for the product delivery tube 218 and former 216 to be made as a unit that is easily interchangeable, so that different size packages can be made by the same machine. The length of the transverse seal can also be changed, by exchanging the sealing jaws 226, or in some cases, merely by exchanging their facings (the portion of the sealing jaws which actually makes contact with the packaging film). By changing these elements, as well as the width of film roll feeding into the machine and the programming of the machine, one form, fill, and seal machine can handle a number of different products in different size packages, limited primarily by the width of film the machine will handle, the maximum length of bag the machine is designed to handle, and the available former/delivery tube assemblies.
Although there is no one perfect package for all uses, there are a number of desirable features that manufacturers strive for in packages made on a vertical form, fill, and seal machine. One such feature is the ability to easily open the package. Consumers now must grip and open the package, usually with a thumb and one or several fingers on both hands. The thumb and fingers must pinch and tear with sufficient force to break the seal. This can become more difficult as a consumer gets older. For example, some consumers have arthritis or have lost strength in their hands. Grasping the sides of a flexible bag and opening it as previously described may be a difficult task for them. Therefore, it is desirable to have a bag that is easier to open by hand than is available from the prior art. There have been some attempts at this to include an easy open package containing, for example a tear notch and perforations that allow for easier opening. However, even these traditional pillow containers have a downside in that when opened the package falls on its side and consequently must be balanced to keep product from spilling. Thus, it is desirable to have a package that does not need to be balanced for fear of spillage. New stand-up packages have been developed that ease the balancing problem such as the package disclosed by commonly owned U.S. Pat. No. 6,722,106 to Bartel et al. However, these vertical stand-up packages still only offer a small cross-sectional area from which product can be retrieved. Many consumers prefer the ease of eating snacks from a plate or a bowl that offers a relatively large surface area for product retrieval rather than a package wherein a consumer's hand must be inserted into the package to retrieve a food product. Thus, it is also desirable to have a package that offers maximum surface area from which product can be retrieved. Consequently, it is desirable to have an easy to open package that upon opening functions as a "plate-mat" which holds food product. The word "plate-mat" comes from combining plate and placemat, and means a container that is generally horizontal when opened such that it can be eaten from like a plate. A feature of the container can also be used as a placemat once the container is open. Finally, because of the speed and productivity achieved on a vertical form, fill, and seal machine, it is desirable that any such package alteration be capable of being produced on such a machine.
SUMMARY OF THE INVENTION
A flexible easy to open package that also serves as a plate for storing and eating food and method for making same is provided. The package comprises two seals: a lower seal and an upper peelable seal. The upper seal has geometry so that as the seal is pulled downward, the force gets distributed downward and outward. There is a portion of unsealed film above the upper seal which forms a tab. This allows a consumer to easily grip the tab and pull downward, breaking the upper seal and opening the package. The inner layer of the package has score lines. Consequently, as the consumer breaks the upper seal, the package continues to tear along the direction of the score lines. Once opened, the package resembles a plate. Further, the torn top portion of the package can be used as a place-mat upon which cups or drinks or other items may be placed.
The package is capable of being produced on a vertical, form, fill, and seal machine with only minor alterations. First, a film is obtained wherein the first layer, or product side, of a film web comprises score lines. The film is oriented so that it preferentially tears in the direction of the score lines. The resulting film is fed to a vertical, form, fill and seal machine. The package is then formed into a tube, sealed at the bottom, filled with product, and then sealed at the top with a peelable seal. The peelable seal is made peelable by adjusting such factors as time, temperature, pressure, as well as the geometry of the seal. Further, the peelable seal has a force distributing configuration which directs the force downward and outward along the package as the consumer opens the package.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:
FIG. 1 depicts a cross-section of an exemplary prior art packaging film.
FIG. 2 depicts a vertical form, fill, and seal machine that is known in the prior art.
FIG. 3 depicts a perspective view of one embodiment of a package in the instant invention.
FIG. 4 depicts a top planar view of one embodiment of the instant invention wherein the top has been torn to reveal a plate of product.
FIG. 5 depicts a cross-section of a packaging film of one embodiment of the current invention.
FIG. 6 depicts the formation of the packaging film of FIG. 5 according to one embodiment.
FIG. 7 depicts a top planar view of the packaging film which is used to produce the plate-mat package.
FIG. 8 depicts a perspective view of one half of the seal jaws and jaw face used in one embodiment of the current invention.
Several embodiments of Applicants' invention will now be described with reference to the drawings. Unless otherwise noted, like elements will be identified by identical numbers throughout all figures.
FIG. 3 depicts a perspective view of one embodiment of a package under the instant invention. The package preferably comprises a flexible film web and more preferably comprises an oriented film such as an oriented polymer material. As used herein a flexible film web is a web comprising at least two flexible layers. An oriented polymer material is a polymer material which has been specially treated so that the long polymeric molecules tend to align in a given direction, causing the material to preferentially tear in that direction. The package is preferably oriented so that it preferentially tears along its vertical axis. The package in this embodiment further comprises a front panel 306 comprising a left and right side, a back panel 307 contiguous with the front panel, a bottom seal 301, an upper seal 302, at least two score lines 303 vertically oriented along the right and left side of the front panel and running parallel from the upper seal to the bottom seal, tear slots 304, and a tear tab 305. The bottom seal 301 is formed by heat seal jaws similar to those depicted in FIG. 2. It should be noted that the top portion of the bag comprises a tear tab 305 which is an extension of the package film above the upper seal 302. Thus, the top most portion of the bag between the tear slots 304 and above the upper seal 302 is not sealed. Because the front panel 306 is not sealed with the back panel 307 in this area, a tear tab 305 is formed. Two or more tear slots 304 can be made by any means known in the art such as a knife and anvil. It can be appreciated that because the tear tab 305 is not sealed a consumer can grip the tear tab with ease. Thus, a consumer can grab the tear tab 305 on the top panel 306 of the package and easily manipulate it as it is not sealed to the back face 307 of the package. In some larger packages, the tear tab 305 will be large enough for a consumer to grab with an entire hand. Even in smaller packages, the tear tab 305 will be large for the consumer to securely grab the tab with a plurality of fingers. After grabbing the tear tab 305, a consumer can exert a downward force. The downward force will follow the path of least resistance in the direction provided by the tear slots 304.
Upon pulling the tear tab 305, the consumer's force will first be directed upon the tip 308 of the upper seal 302. As will be discussed in more detail below, the upper seal 302 is a peelable seal which is typically easier to destroy. It can be seen that one benefit of the upper seal 302 is that the seal comes to a tip 308. As depicted, the upper seal 302 is a chevron seal. The use of a chevron seal is shown only as a preferred embodiment and should not be deemed limiting. Other possible examples include a semicircle or any other shape that exhibits a force distributing configuration. As used herein a force distributing configuration is a configuration that concentrates the force at a force concentrating area such as a narrow tip and then distributes the forces downward and outward. Other shapes that do not concentrate the initial force at a narrow tip can be used, but such shapes result in increased force being necessary to initiate the tear and open the package. The seal has a seal area of a defined width and length. In a preferred embodiment the seal has a tip 308, defined herein as a force concentrating area. In a preferred embodiment the seal area at the tip is narrower than the width of the seal along the rest of the seal. Such a configuration allows for even greater concentration of force resulting in easier tear initiation. A chevron seal is used as the upper seal 302 in part because of its defined tip 308, In a preferred embodiment the width of the tip 308 of the upper seal 302 is between about 1/32nd and about 1/4th of an inch and is narrower than the width of the seal 302 along other portions of the seal 302. In a more preferred embodiment the width of the tip 308 of the upper seal 302 is between about 1/16th of an inch and about 1/8th of an inch. The downward force exerted by the consumer will be concentrated on the tip 308, resulting in less required force to destroy the seal 302 at the tip 308, thus initiating the opening of the seal 302. If the upper seal 302 did not come to a tip or was thicker, the force would be less concentrated and consequently more force would be required to destroy or open the seal.
When the seal is destroyed, the force exerted gets distributed downward and outward along the package in the same direction of the upper seal 302. As the forces distribute outward, they run across a plurality (three in the embodiment illustrated) of score lines 303a, 303b, 303c, 303d, 303e, 303f on either side of the package. As used herein score lines encompasses lines which have been partially scored into the material, completely slit through the material, or perforated. In the pictured embodiment there are three score lines 303a, 303b, 303c, 303d, 303e, 303f which run the entire length of the package on both sides, left and right, of the package. In one embodiment of the current invention, it is preferred that these score lines 303a, 303b, 303c, 303d, 303e, 303f on either side be separated by about 1/10th of an inch to about one inch. It is more preferable that the score lines be separated by about 1/8th to about 1/2 of an inch. It is most preferable that the score lines be separated by about 1/4 of an inch. It is desirable, though not required, to form score lines 303a, 303b, 303c, 303d, 303e, 303f such that when the package is filled with product the outermost score lines 303c, 303f are close to the product edge. This results in a greater possible planar surface area of the plate when the package is opened. In one embodiment of the current invention it is preferred that the outermost score lines be located from about 1/16th of an inch to about four inches from the edge of the package.
As a consumer pulls down on the tear tab 305, the force will run down the upper seal and into one of these three score lines 303a, 303b, 303c, 303d, 303e, 303f. Having multiple, or in this case three score lines 303a, 303b, 303c, 303d, 303e, 303f on either side is helpful, though not required, as it provides some room for error; if the tear does not intersect the innermost slot, the tear will continue until it intersects the outermost slot and the tear will continue to run vertical with the length of the package. As noted above, the oriented polymer material has been specially treated so that the long polymeric molecules tend to align in a given direction, causing the material to preferentially tear in that direction. Thus, because the polymer material is oriented so as to align with the score lines lines 303a, 303b, 303c, 303d, 303e, 303f, the material preferentially tears in the same direction as the score lines 303a, 303b, 303c, 303d, 303e, 303f. If the material was oriented perpendicular to the score line the material would not tear along a straight path. The polymer material is treated to cause this alignment in the formation of the material before the film layers are selected for lamination.
FIG. 4 depicts a top planar view of one embodiment of the instant invention wherein the top 401 has been torn to reveal a plate of food. The top 401, once removed, can be used as a type of placemat. For example, cups can be placed on the top 401 instead of a coaster to protect a tabletop. Returning to FIG. 4, it can be seen that the top 401 has been torn along the middle score lines 303e, 303b. Two score lines 303a, 303d are visible in the innermost layer of the torn top portion 401. Additionally, two score lines 303c, 303f remain on the plate portion of the package. Thus, FIG. 4 shows an open package that has been opened with a tear following the middle score line. Note that while this embodiment has been shown with three score lines on either side of the package that is not so limiting. Virtually any number of score lines, from one up, is possible. Once the package is open, as depicted in FIG. 4, the bag sits firmly on a surface. The torn top 401 reveals the package contents. In one embodiment the bag comprises snack foods such as potato chips. A consumer would be able to consume or use the package's contents without the need to balance the bag for fear of spillage. Further, the open surface of the instant invention offers a greater relative surface and allows for easier removal of the product contents compared to prior art bags that offered only a relatively small opening for removal of the product. Thus a consumer can easily open the package using the tear tab 305 and place the open package on a surface, utilizing the open package as a plate.
Referring now to FIG. 5, one aspect of the instant invention becomes clear. Whereas in FIG. 1 the outside of the bag is an OPP layer 102 and the product side of the bag is a metallic OPP layer 106 with a sealant 108, the instant invention has those layers reversed. Referring to FIG. 5, in one embodiment the outermost layer of the instant invention is a metalized OPP layer 106 with a sealant layer 108. As discussed above, the sealant layer 108 can comprise barrier properties. As used herein barrier properties means any layer which provides a barrier to oxygen or moisture and helps to retain taste and freshness of the product contained therein, An OPP layer 102 is the innermost, product side layer of the package. An adhesive layer 104 is between the OPP layer 102 and the metalized OPP layer 106, 108. Thus, whereas the metalized layer 106, 108 was on the inside of the package in the prior art, in the instant invention the metalized layer 106, 108 is actually on the outside of the package. The reason for this arrangement can better be seen referring back to FIG. 3. As discussed above, FIG. 3 has three pairs of score lines 303a, 303b, 303c, 303d, 303e, 303f that run the entire length of the package. It is a preferred embodiment of the instant invention that these score lines be on the innermost layer of the invention of the bag. As a consumer pulls on the tear tab 305, the force destroys the seal at the tip 308 of the upper seal 302 and continues downward and outward until the tear encounters a score line 303a, 303b, 303c, 303d, 303e, 303f. Because in this embodiment the score line is formed in the innermost layer, when the downward force is applied, the innermost layer breaks and tears in the direction of the force. This in turn causes the outermost layers to tear in the same direction and location. Thus, because the score lines 303 are located in the innermost layer which is below the outermost layer, any force to separate the innermost layer must cause a tear in the outermost layer.
Referring back to FIG. 5, it becomes obvious that there are many different possibilities for film layers that would result in a similar outcome of the current invention. The basic requirements of the instant invention are that one layer comprise a score line and that one layer comprise barrier properties. These barrier properties are essential in keeping oxygen and moisture from contacting and adversely affecting the product within the container. It can be appreciated that while one embodiment has stated the use of OPP as the innermost layer, other materials can be suitably used. Virtually any layer that is capable of laminating or adhering with another layer comprising barrier properties may be used for the innermost layer. Likewise, while a metalized OPP layer has been described for the outer layer, virtually any layer which comprises adequate barrier properties can be used.
FIG. 6 depicts the formation of making score lines 303a, 303b, 303c, 303d, 303e, 303f in one embodiment. FIG. 6 depicts the formation of the packaging film of FIG. 5 wherein the innermost layer of the package is slit completely through. It should again be noted that this invention is not limited to situations where the innermost layer is slit completely through. Other methods such as scoring or perforating may also be used. FIG. 6 depicts a slightly altered method which was disclosed by commonly owned U.S. Pat. No. 7,189,300 B2 to Knoerzer et al. which is incorporated herein. First an OPP layer 102, which in this embodiment is the innermost film in the package, is slitted. It is slit by slitters 603 resulting in a film with parallel score lines. If three score lines on either side of the package are desired, then there will be six total slitters. After an OPP layer 102 has been cut resulting in score lines 303, the OPP layer 102 is laminated using an adhesive 104 to the outermost layer comprising an OPP metalized layer 106 and a sealant 108. The resulting film 500 comprises an OPP layer 102 with score lines laminated to an OPP layer 106, 108 which comprises barrier properties. It should be noted that while reference has been made to a single film layer, it is possible, and may be preferred that each layer comprise multiple layers.
FIG. 7 shows a planar view of the composite film 500 that will make up one example container or bag. The width 704 and length 706 of each composite film 500 can be varied to produce bags of various sizes. Note, that if the composite film 500 is fed to a traditional form, fill, and seal machine, the composite film 500 is in a continuous sheet. It is then formed into a tube, sealed at one end, filled, sealed at a second end, and cut to form the resultant bag.
As an example, to produce a five inch wide bag, the width of the composite film 704 will be about eleven inches. If three score lines are desired on either side of the bag, and each score line is separated by about one-quarter of an inch, then the distance 705 between middle score lines 303b, 303e will be about four inches. The distance 701 between the middle score line on the right 303e and the right side of the film composite will be about 3.75 inches. The distance 703 between the middle score line of the left 303b and the left side of the film composite will be about 3.25 inches. Thus, it is apparent that the distance 702 between middle score lines 303b, 303e is dependent upon the width of the composite film 704, the distance between score lines 705, and the number of score lines. Thus, if an eight inch bag is desired, with six score line separated by about one-quarter inch, the resulting composite film would have a distance of about seven inches between the left and right middle score lines. Accordingly, if the package was opened along the middle score line, the resulting plate would have an open area width of about seven inches. It should be noted that the dimensions and ratios stated above are for one preferred embodiment and are given only as an illustrative example. Many other dimensions and ratios may also be preferred and can be obtained without varying from the scope of this invention.
The composite film 500 is then fed to a traditional form, fill and seal machine, similar to that shown in FIG. 3 but with minor alterations. The film is fed such that the score lines are parallel to the direction of film travel. An alteration made to a traditional form, fill, and seal machine includes replacing the heat seal jaws 226 with a modified jaw that provides both the vertical bottom seal 310 and the upper seal 302 as seen in FIG. 3. These modifications can best be understood by reference to FIG. 8.
FIG. 8 depicts a perspective view of the seal jaws and jaw face used in one embodiment of the current invention. FIG. 8 only shows a perspective view of one of the seal jaws and in operation two seal jaws would act in concert to form both seals. The top portion of FIG. 8, the bottom sealer 801, is a horizontal seal which makes the bottom seal 301. The bottom portion of FIG. 8, the upper sealer 802 seals the top portion of the bag by making upper seal 302. The upper sealer 802 as depicted has the shape of an inverted "V" and would result in the chevron seal shown in FIG. 3. It should be noted that the upper sealer 802 can comprise various shapes. It naturally follows that the upper sealer 802 can produce an upper seal 302 with many different shapes such as the chevron or a semi-circle. Virtually any shape which directs force downward and outward can be utilized. It can be seen that there will be a layer of film 805 defined by the length between the distance of the bottom sealer 801 and the upper sealer 802 that is not sealed. This is what results in the tear tab 305 that provides for easy opening. It should be noted that the lengths of both the bottom sealer 801 and the upper sealer 802 exceed the width of the bag to be sealed. If the lengths of the seals do not exceed the width of the bag, then the entire bag will not be sealed, and oxygen and moisture will be able to penetrate the bag.
In operation, the upper sealer 802 and the bottom sealer 801 are separated by a distance defined by the length of unsealed film 805. This distance will vary from about half an inch for smaller bags to about four inches or more for larger bags. The bottom sealer 801 is located above the upper sealer 802 by a distance 803 defined by the separation from the tip of the upper sealer 808 to the bottom sealer 801. This distance 803 will vary with the size of the bag. Suitable distances include from about one-half an inch for smaller bags to about four inches or more for larger bags. In operation, while the bottom sealer 801 is forming a bottom seal 301 for a bag above the bottom sealer 801, upper sealer 802 is forming an upper seal 302 for a bag located below the bottom sealer 801. After the two seals are formed, a knife, or other means (not shown) cuts the film beneath the bottom sealer 801 to form two separate bags.
It should also be noted that the seal produced by the upper sealer 802 is typically different from the bottom seal 301 in that the upper seal 302 is peelable. It should be noted however, that in some embodiments it may be desirable that the bottom seal 301 also comprise a peelable seal. As used herein a "peelable seal" is a seal which can be broken along a specified direction of travel, and which is typically easy to open. In one embodiment the peelable seal requires less force to destroy than a destructive seal. A destructive seal is a seal that cannot be opened without tearing. In many embodiments the peelable seal is easily opened with two hands. It is possible to produce a peelable seal in many ways which are discussed below. In one embodiment, the geometry of the upper seal 302 is manipulated to produce a seal which is easier to open. For example, in one embodiment the peelable upper seal 302 comprises a line seal. A line seal is a very narrow seal. Because the line seal is narrow, it requires less force to destroy than a wider seal. Thus, the peelable upper seal 302 can comprises an easy to open line seal whereas the bottom seal 301 comprises a traditional permanent or destructive seal. In some embodiments, the upper seal 302 and bottom seal 301 comprise the same seal type, for example a permanent seal, but the upper seal 302 is narrow making it easy to open and thus peelable. In another embodiment the peelable upper seal 302 comprises resin in what is sometimes referred to as a peelable sealant by design. Typically, in such an embodiment resin is applied to the entire film of the package. Upon the application of heat and pressure a seal forms between the two films comprising layers. The strength of the resultant seal is adjusted by varying the amount of heat applied to the seal, the pressure applied to the seal, the length of time the heat and pressure are applied to the seal, as well as the geometry of the seal. Thus, two seals of varying strength may be made by varying the temperature and pressure applied to a given seal. Likewise, as discussed above, one seal can be weaker and thus easier to open than a second seal if it is thinner than the second seal. In other embodiments the resin may be applied selectively to the area being sealed resulting in a peelable seal. In yet another embodiment the peelable upper seal 302 comprises a cold seal, for example, glue. Thus, there are many methods which produce a peelable seal. Any of these methods may be used to produce upper seal 302. In many embodiments of the current invention the upper seal 302 requires less force to destroy than the bottom seal 301. The reason the upper seal 302 needs to be peelable is that in the operation of this bag a consumer grabs the tear tab and pulls downward. As the consumer pulls downward, the force of the tab being pulled downward along the length of the package will be sufficient to separate the front and back layers of the package so that the seal is destroyed and the package is opened. Consequently, the upper seal 302 needs to be peelable to allow for this operation. If the seal was not peelable, then the package will just rip apart instead of following the path of the seal. Further, if the seal was not peelable then more force is typically required to destroy it. It should now be noted that while FIG. 8 depicts the upper sealer 802 and the bottom sealer 801 as being on the same seal jaw 803, it is possible, and it may be more desirable to have each sealer on its own seal jaw. Such an arrangement allows increased flexibility in forming seals with different attributes.
In summary, the invention allows the production of a flexible film having an easily opened package that when opened operates as a plate. Many other variations are possible without straying from the intent of this inventive disclosure and will be obvious to one of ordinary skill in the art.
Patent applications by Joe Sagel, Plano, TX US
Patent applications in class BAG CLOSURE SECURED BY A RELEASABLE OR FRANGIBLE BOND (E.G., PEEL SEAL)
Patent applications in all subclasses BAG CLOSURE SECURED BY A RELEASABLE OR FRANGIBLE BOND (E.G., PEEL SEAL)