US20050286811A1 - Autoclavable reclosable package - Google Patents

Abstract

A reclosable package that seals an enclosed product and allows the product to be subjected to a retort procedure to cook the product while the product is in the package. The reclosable package is formed from a polypropylene film and includes a zipper closure including a pair of mating closure profiles both formed from a polypropylene material. One of the male or female closure profiles includes a sealing flange having a layer of sealant such that the sealing flange provides a seal for the package below the interaction between the closure profiles. This seal prevents the product from migrating through the profile member during the retort procedure and prior to the package being opened for the first time.

Description

CROSS REFERENCE TO RELATED APPLICATION
• The present application is a divisional of application Ser. No. 10/726,731, filed on Dec. 2, 2003, which claimed the benefit of U.S. Provisional Patent Application Ser. No. 60/430,727, filed on Dec. 3, 2002, both disclosures of which are fully incorporated by reference herein.
FIELD OF THE INVENTION
• The present invention generally relates to a package having a reclosable zipper member positioned at the mouth of the package to allow the package to be reclosed after initial opening. More specifically, the present invention relates to a zipper closure that hermetically seals the contents of the package and can withstand the temperatures associated with a retort procedure.
BACKGROUND OF THE INVENTION
• Many packaging applications use reclosable containers to store various types of articles and materials. These packages may be used to store and ship food products, non-food consumer goods, medical supplies, waste materials, and various other types of articles. Reclosable packages are convenient in that they can be closed and resealed after the initial opening to preserve the enclosed contents. The need to locate a storage container for the unused portion of the product in the package is thus avoided. As such, providing products in a reclosable package appreciably enhances the marketability of these products.
• Although reclosable packages have been around for quite some time and are used for storing various types of food products, currently available reclosable packages are not constructed to be used with food products that are subjected to a retort procedure after the food products have been placed into the reclosable package. During the retort procedure, the contents of the package are typically subjected to temperatures of 255° F. for a specified period of time to cook the food in its own package, thereby extending shelf life and insuring food safety. Food items such as tuna are often subjected to this type of retort procedure.
• Currently available reclosable packages cannot withstand the temperature requirements of the retort procedure. Specifically, the zipper closure used across the open mouth of the package is typically formed from a polyethylene material that cannot withstand the temperatures required for the retort or autoclave sterilization process.
• Further, packages used during a retort procedure are made from a polypropylene film that can withstand the temperature of the retort procedure. Currently available zipper closures made from polyethylene do not form an adequate bond with the polypropylene film and thus cannot be used for a sealed package.
• Food products that are contained within a reclosable package that are subjected to the retort procedure must be hermetically sealed to prevent contamination. Thus, the zipper closure across the mouth of the package must provide a hermetic seal across the width of the package in order to prevent contamination of the enclosed products before the package is initially opened. Typically, the snap fit between the male and female profile elements of a zipper closure does not provide a hermetic seal.
• During the retort procedure, the contents of the package, such as food particles or liquids, have a tendency to migrate through the mated closure profile and into the package header area of the pouch. When a user tears the pouch header open, the consumer then handles the gripping area above the closure profiles in order to separate the individual members of the zipper closure. Since many products contained within a retort package are messy and possibly greasy, accessing the package interior through the zipper closure becomes more difficult if the product migrates past the closure profile members.
• Therefore, it is an object of the present invention to provide a reclosable package having a zipper closure formed from a material that can withstand the temperatures during the retort procedure. Further, it is an object of the present invention to provide a reclosable package that provides a hermetic seal across the package mouth to prevent contamination of the enclosed products prior to the initial opening of the reclosable package.
• Yet a further object of the present invention is to provide a reclosable package that prevents the migration of the packaged food product past the zipper closure prior to opening of the reclosable package.
SUMMARY OF THE INVENTION
• The present invention is a reclosable package that allows the contents of the package to be subjected to a retort procedure while the product is contained within the package. Further, the product package provides a hermetically sealed enclosure that includes a tamper evident feature such that a user can determine if the package has been previously opened. The product package further prevents the migration of the packaged food product past the zipper closure during the retort procedure and prior to opening of the releasable package.
• The reclosable package is formed from a packaging film that is shaped into a reclosable package using conventional bag forming techniques. However, the packaging film used to create the reclosable package of the present invention is preferably a polypropylene material that can withstand the retort temperatures of 255° F. for up to 84 minutes.
• The product package includes mating male and female closure profiles formed on opposite side panels of the product package. The male and female closure profiles mate with each other to allow the product package to be repeatedly opened and reclosed by a user. In the reclosable package of the present invention, both of the male and female closure profiles are formed from a polypropylene material such that the closure profiles can be bonded to the polypropylene side panels. The male and female closure profiles can be bonded to the side panels using either heat alone or heat in combination with a sealant placed between the closure profiles and the side panels. Preferably, the sealant is a polypropylene-based adhesive resin that provides for a strong bond between the closure profiles and the side panels.
• In accordance with a first embodiment of the invention, one of the closure profile members includes a sealing flange that extends from an attachment flange used to secure the profile to the side panel of the product package. The sealing flange is separated from the attachment flange by a die line or other line of weakness such that the sealing flange can flex relative to the attachment flange. Preferably, the sealing flange includes a layer of sealant on its inner surface.
• During the formation process of the product package, the sealant on the sealing flange is attached to the side panel opposite the side panel to which the closure profile including the sealing flange is attached. In this manner, the sealing flange provides for a hermetic seal along the entire width of the product package. This seal prevents the product from migrating into contact with the zipper closure during the retort procedure.
• The sealant used on the sealing flange is selected such that the sealant forms a bond with the side panel that both provides a hermetic seal and is strong enough to allow the sealing flange to separate from the closure profile along the line of upon initial opening of the product package.
• In an alternate embodiment of the invention, the closure profiles attached to the opposed side panels of the product package are joined to each other by a pair of connector flanges. Thus, the pair of closure profiles and connector flanges are formed as a one piece structure. The connector flanges are separated from each other by a reduced material thickness die line such that the closure profile can be separated along the die line.
• The attachment of the pair of closure profiles along the die line in the alternate embodiment of the invention provides for a hermetic seal beneath the interacting portions of the closure profile. Thus, the product contained within the product package is hermetically sealed and prevented from migrating past the zipper closure, regardless of the state of interaction between the interlocking members of the closure profile. In the alternate embodiment of the invention, the closure profiles and the side panels of the reclosable package are both formed from a polypropylene material that can withstand the temperatures associated with the retort procedure.
BRIEF DESCRIPTION OF THE DRAWINGS
• The drawings illustrate the best mode contemplated of carrying out the present invention. In the drawings:
• FIG. 1 is a side view of a flexible, reclosable package having the zipper closure of the first embodiment of the present invention in an open condition prior to product loading;
• FIG. 1ais a magnified section view of the zipper closure ofFIG. 1;
• FIG. 2 is a side view illustrating the loading of a product into the reclosable package including the zipper closure of the present invention;
• FIG. 3 is a side view illustrating the reclosable package in a sealed condition including a product such that the product can be subjected to the retort procedure;
• FIG. 4 illustrates the removal of a header from the product package prior to initial opening;
• FIG. 5 is a side view illustrating the separation of the sealing flange from the closure profile along the line of weakness during the initial opening of the product package;
• FIG. 6 is a side view of a second embodiment of the zipper closure;
• FIG. 6ais a magnified view of the second embodiment of the zipper closure shown inFIG. 6;
• FIGS. 7a-7care side views of a third embodiment of the zipper closure and illustrate the sealing of the zipper across the package interior and the separation of the sealing flange from the package sidewall during the initial opening of the product package;
• FIGS. 8a-8care side views of a fourth embodiment of the zipper closure illustrating the attachment of the sealing flange across the open package interior and the separation of the sealing flange from the package sidewall during the initial opening of the product package.
• FIGS. 9a-9care side views of a fifth embodiment of the zipper closure showing the attachment of the sealing flange across the package interior and the separation of the sealing flange from the sidewall during the initial opening of the product package;
• FIGS. 10a-10dare side views illustrating a sixth embodiment of the zipper closure and further showing the attachment of the sealing flange across the open package interior and the separation of the sealing flange from the sidewall during the initial opening of the product package;
• FIGS. 11a-11bare side views of a seventh embodiment of the zipper closure;
• FIGS. 12a-12care side views of an eighth embodiment of the zipper closure and illustrate the connection of a pair of sealing flanges and the separation of the sealing flanges during the initial opening of the product package;
• FIGS. 13a-13care side views of the ninth embodiment of the zipper closure and illustrate the interconnection between a pair of sealing strips and the separation of the sealing strips during the initial opening of the product package;
• FIGS. 14a-14cillustrate a tenth embodiment of the zipper closure and illustrate the attachment of the zipper closure to the package sidewalls;
• FIGS. 15a-15care side views of an eleventh embodiment of the zipper closure and illustrate the separation of the sealing flange from the closure profile during the initial opening of the product package;
• FIG. 16ais a side view of yet another embodiment of a zipper closure that can withstand the retort procedure and provide a hermetically sealed product package;
• FIG. 16bis a magnified view of the area illustrated by line16-16 inFIG. 16a;
• FIG. 17 is a side view illustrating the bottom filling of the reclosable package including the embodiment of the zipper closure ofFIG. 16a;
• FIG. 18 is a side view illustrating the sealing of the reclosable package prior to the retort procedure;
• FIG. 19 is a view illustrating the removal of the package header prior to initial opening the reclosable package;
• FIG. 20 is a magnified view illustrating the initial opening of the reclosable package;
• FIG. 21 is a side view illustrating the separation of the zipper closure profile elements along a die line to provide access to the product contained within the reclosable package;
• FIG. 22 is a side view of an alternate embodiment of a zipper closure for a bottom-fill reclosable package that can withstand the retort process;
• FIG. 23 is another embodiment of a zipper closure for a bottom filled reclosable package that can withstand the retort process;
• FIG. 24 is another embodiment of a zipper closure for a bottom filled reclosable package that can withstand the retort process;
• FIG. 25 is another embodiment of a zipper closure for a bottom filled reclosable package that can withstand the retort process;
• FIG. 26 is another embodiment of a zipper closure for a bottom filled reclosable package that can withstand the retort process;
• FIG. 27 is another embodiment of a zipper closure for a bottom filled reclosable package that can withstand the retort process; and
• FIG. 28 is another embodiment of a zipper closure for a bottom filled reclosable package that can withstand the retort process.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
• Referring first toFIG. 1, thereshown is areclosable package10 of the present invention. Thereclosable package10 is formed from a first and a second polymericfilm side panels12 and14 defining anopen interior16. In the embodiment of the invention illustrated, theside panels12 and14 are joined to each other by agusseted bottom wall18 that allows theopen interior16 of thereclosable package10 to expand. Although thereclosable package10 is illustrated inFIG. 1 as having the gusseted bottom18, it should be understood that thereclosable package10 could be formed without the gusseted bottom while operating within the scope of the present invention.
• As illustrated inFIG. 1, thepackage10 has anopen mouth20 defined by thetop edges22,24 of theside panels12 and14. Theopen mouth20 allows a user access to theopen interior16 of thepackage10 and allows for a product to be loaded into thepackage10.
• As illustrated inFIG. 1, azipper closure26 is attached to the package near theopen mouth20 and extends across the entire width of the package between a pair of side edges (not shown). Thezipper closure26 can include a variety of configurations and structures while operating within the present invention, a number of which will be set forth below.
• In the embodiment of the invention illustrated inFIG. 1, thezipper closure26 includes amale closure profile28 and a matingfemale closure profile30. Specifically, themale closure profile28 includes a male closure post32 that is received within agroove34 formed between a pair of female closure posts36 and38. The mating interaction between themale closure post32 and the pair of female closure posts36,38 provide for an interlocking seal between the pair of closure profiles28 and30. The specific construction and design of themale closure post32 and thefemale closure post36 and38 is shown for illustrative purposes only and does not limit the scope of the present invention. It should be understood that many various configurations for providing an interaction between themale closure profile28 and thefemale closure profile38 are thought to be within the scope of the present invention.
• Referring now toFIG. 1a, in the preferred embodiment of the invention, themale closure profile28 includes a sealingflange40 that extends from theattachment flange42 of themale closure profile28. The sealingflange40 is integrally extruded along with theattachment flange42 and themale closure post32 and is separated from theattachment flange42 by a reduced material thickness dieline44. Thus, the sealingflange40 can pivot relative to theattachment flange42 about thedie line44. Although the sealingflange40 is shown attached to themale closure profile28, it should be understood that the sealingflange40 could also be formed on thefemale closure profile30 while operating within the scope of the present invention. Most importantly, the sealingflange40 extends from one of theside panels12 or14 to the opposing side panel to provide a hermetic seal below the interaction between the closure profiles as will be made clear below.
• The sealingflange40 includes a layer ofsealant46 applied to itsfront surface48. Preferably, thesealant46 is applied to thefront surface48 of the sealingflange40 after the extrusion of themale closure profile28 and prior to installation of theclosure profile28 to theside panel12.
• As illustrated inFIG. 1a, both themale closure profile28 and thefemale closure profile30 are applied to one of theside panels12,14 of the product package. In the embodiment of the invention illustrated, theside panels12 and14 are formed from a polymeric material that can withstand the temperatures associated with a retort procedure. Typically, the retort procedure occurs at approximately 255° F. for 84 minutes or more. Theside panels12,14 illustrated inFIG. 1aare formed from a polypropylene material such that theside panels12,14 can withstand the retort procedure.
• Referring now toFIG. 2, thereshown is the filling of thereclosable package10 by aproduct50. As illustrated, theproduct50 is directed through theopen mouth20 of the reclosable package and is received within theopen interior16. As illustrated inFIG. 2, theproduct50 flows past thezipper closure26, including themale closure profile28 and thefemale closure profile30.
• Once a desired amount ofproduct50 has been placed into thereclosable package10, the mouth of thepackage20 is closed and theside panels12 and14 heat sealed to each other along thetop seal52 near the top edge of each panel, as illustrated inFIG. 3. During the sealing of the top edges, themale closure post32 may or may not be mated with the pair of female closure posts36 and38. Thus, after the product has been placed into thereclosable package10, thetop seal52 close theopen interior16. However, thepackage10 is not hermetically sealed due to the lines ofperforation58 that separate theheader56 from the remainder of the package.
• During creation of thetop seal52, thesealant46 is pressed into contact with the inner surface54 of theside panel14. As illustrated inFIG. 3, the sealingflange40 is thus attached to theside panel14 opposite theside panel12 to which the remaining portion of themale closure profile28 is secured. In the preferred embodiment of the invention, the composition of thesealant46 is selected such that thesealant46 can be heat sealed to the inner surface54 of theside panel14 during the closure of theopen mouth20. Thesealant46 is selected such that the interaction between thesealant46 and the inner surface54 provides a hermetic seal between the sealingflange40 and theside panel14.
• In the preferred embodiment of the invention, theside panels12 and14 are formed from polypropylene and thesealant46 is a polypropylene-based adhesive resin. One example of such a sealant is the Admer® QF552A, which is an anhydride modified copolymer polypropylene-based adhesive resin and available from Mitsui Chemical America, Inc. Thesealant46 has a melt flow value in the range of 5.0 to 9.5 g/10 min based on the ASTM test method D1238. Further, thesealant46 preferably has a density in the range of between 0.85 and 0.93 g/cm³based upon the ASTM test method D1505.
• An important consideration for thesealant46 in the first embodiment of the invention is that the sealant is able to provide a hermetic seal between the sealingflange40 and theside panel14 yet withstand the retort procedure. Typically, the retort procedure occurs at 255° F. for the required period of time to cook the food product while it is in the package. The retort procedure may last as long as 84 minutes or more. During the autoclave and sterilization procedures, the sealant must maintain its integrity and remain attached to theside panel14 to provide a hermetic seal.
• As illustrated inFIG. 3, when the sealingflange40 is attached to theside panel14, theproduct50 within the open enclosure can be subjected to the retort procedure. During this procedure, theproduct50 is cooked in the package and harmful bacteria or other contaminants are killed. This type of retort procedure is typically associated with fresh food products, such as tuna or other perishable items.
• In accordance with the present invention, the closure profiles28 and30 are formed from a specified material such that theprofiles28 and30 can withstand the retort procedure and bond to thepolypropylene side panels12 and14. In prior art available reclosable packages, the closure profiles are formed from a polyethylene material having properties that cannot withstand the autoclave procedure and do not bond well to thepolypropylene side panels12 and14.
• In the present invention including the alternate embodiments to be described below, the male and female closure profiles28 and30 are formed from a random copolymer polypropylene that can withstand the retort process. Specifically, thereclosable profiles28 and30 are formed from a material having a melt index in the range between 1.7 and 3.5 g/10 min as measured using the ASTM test method D1238. Further, the polypropylene material used to form the closure profiles28 and30 has a density in the range between 0.895 to 0.910 g/cm³as measured by the ASTM test method D1505. An example of such a product is the Atofina® copolymer product number 6289MZ. However, other types of polymer materials are contemplated as being within the scope of the present invention.
• As can be understood by the above description, it is important that the material selected for themale closure profile28 and thefemale closure profile30 be able to withstand temperatures of approximately 255° F. for up to an 84 minute period.
• In the embodiment of the invention illustrated inFIG. 3, the male and female closure profiles28 and30 can be attached to theside panels12 and14 either solely through the application of heat or through the combination of heat and a sealant layer between the closure profiles28,30 and theside panels12,14. If a sealant layer is used, the sealant is typically the same as thesealant46 applied to the sealingflange40. Thus, a hermetic seal is also created between each of the closure profiles28,30 and theside panels12,14, as well as along the line ofsealant46.
• Once theproduct50 has been subjected to the retort procedure when it is contained within thereclosable package10, thereclosable package10 including theproducts50 can be shipped to consumers. Upon receipt, the consumer can open the reclosable package by grasping the top tear offheader56, as illustrated inFIG. 4. Referring back toFIG. 3, the top tear offheader56 is separated from the remaining portions of theside panels12 and14 by lines ofperforation58 contained in each of theside panels12 and14. Once the top tear offheader56 has been separated, the user can access the pair of closure profiles28 and30.
• As can be understood by the above description, the seal between the sealingflange40 and theside panel14 prevents thefood product50 from migrating through the zipper closure and into contact with the grippingridges60 formed on the pair of closure profiles28 and30, as illustrated inFIG. 4. Since the food product contained within the package may be greasy or messy, the prevention of the migration of the food product past the zipper closure allows the user to more easily grasp the grippingridges60 to open the package.
• Referring now toFIG. 5, once the user has grasped the grippingridges60, the male and female closure profiles28 and30 can be pulled apart to open themouth20 as illustrated. As themouth20 is opened, the sealingflange40 separates from theattachment flange42 along thedie line44 and remains attached to theside panel14, as illustrated inFIG. 5. In the embodiment of the invention illustrated, thesealant46 forms a sufficiently strong bond with theside panel14 such that the sealingflange40 separates from theattachment flange42 before the sealingflange40 is released from theside panel14. Thus, in addition to providing a seal to prevent product migration past the zipper closure, the combination of the sealingflange40 and thesealant46 acts as a tamper evident feature for the opening of theproduct package10.
• After the sealingflange40 has been separated, theproduct50 can be removed through theopen mouth20 and thepackage10 resealed by re-engaging themale closure profile28 and thefemale closure profile30.
• Referring now toFIG. 6, thereshown is an alternate embodiment of themale closure profile28. In the second embodiment, the sealingflange62 has a semi-circular configuration and includes a pair ofdie lines64 and66. The sealingflange62 is attached to theattachment flange42 and separates from theattachment flange42 when theproduct package10 is opened for the first time.
• As can be seen inFIG. 6a, thesealant46 is applied to theouter end68 of the sealingflange66 and contacts theside panel14 to form a hermetic seal between the sealingflange62 and theside panel14. In the embodiment of the invention illustrated inFIG. 6, thesealant46 and the closure profiles28 and30 are formed from the same material illustrated and described inFIGS. 1-5.
• Referring now toFIGS. 7a-7bthereshown is another alternate embodiment for the zipper closure to be used across theopen mouth20 of a product package that can be subjected to the retort process. The zipper closure includes amale closure profile28 and afemale closure profile30 that are designed to mate and engage to hold theopen mouth20 closed. In the embodiment of the invention illustrated, the male closure profile includes a depending sealingflange86. The sealingflange86 includes a layer ofreleasable sealant88 on itsfirst face surface90 and a layer ofpermanent sealant92 on the opposite,second face surface94. In the embodiment of the invention illustrated, thepermanent sealant92 has the same composition as thesealant46 included on the sealingflange40 shown inFIG. 5.
• When thereclosable package10 is in the closed position shown inFIG. 7b, thepermanent sealant92 is in contact with theside panel14 while thereleasable sealant88 contacts theside panel12. In this position, the sealingflange86 prevents product from seeping past the closures and contacting the grippingridges60. When thereclosable package10 is opened for the first time, as illustrated inFIG. 7c, the sealingflange86 separates from theside panel12 along thereleasable sealant88. Thus, thereleasable sealant88 forms a “peel seal” between the sealingflange86 and theside panel12. In the preferred embodiment of the invention, thereleasable sealant88 is an FDA approved sealant.
• Referring now toFIGS. 8a-8c, thereshown is yet another embodiment of the zipper closure positioned along themouth20 of thereclosable package10. In the embodiment of the invention illustrated, themale closure profile28 includes a sealingflange96. The sealingflange96 is formed integrally with the remaining portions of themale closure profile28 and includes areleasable sealant98 applied to thefront face100 of the sealingflange96. As illustrated inFIG. 8b, thereleasable sealant98 creates a seal between the sealingflange96 and theside panel12 to prevent the product from seeping between the closure profiles prior to opening. When thepackage10 is opened for the first time, as shown inFIG. 8c, thereleasable sealant98 separates from theside panel12 and allows for access to the contents of the package. As discussed above in the embodiment shown inFIGS. 7a-7c, thereleasable sealant98 is preferably an FDA approved sealant for contact with food products.
• Referring now toFIGS. 9a-9c, thereshown is yet another embodiment of a method for creating thereclosable package10. In the embodiment of the invention illustrated, thezipper closure26 is initially installed in a mated condition. Specifically, themale closure profile28 and thefemale closure profile30 are installed in the mated condition shown inFIG. 9a. As shown, thefemale closure profile30 is initially attached to theside panel12 through the application of heat or an adhesive while themale closure profile28 is spaced from theside panel14. When thezipper closure26 is in the position shown inFIG. 9a, product can be fed into thepackage interior16 through theopening95 that exists between theside panel14 and themale closure profile28.
• Once the package has been filled, themale closure profile28 is attached to theside panel14 through the application of heat or an adhesive. At the same time, the sealingflange96, including thereleasable sealant98, is secured to theopposite side panel12. As can be understood inFIGS. 9aand9b, the method of the invention allows the product to be filled past the zipper, rather than through the zipper as in the previously described embodiment ofFIGS. 8a-8c.
• When thereclosable package10 is opened for the first time, the sealingflange96 separates from theside panel12 along the layer ofreleasable sealant98.
• Referring now toFIGS. 10a-10c, thereshown is yet another embodiment of the invention similar to the embodiment shown inFIGS. 9a-9c. As described above, thezipper closure26 is initially installed in a mated condition and product is fed into the open interior16 through theopening95 between theside panel14 and themale closure profile28. However, in the embodiment shown inFIG. 10a, the sealingflange96 is separated from the remaining portions of themale closure profile28 by a line ofweakness100. Additionally, the sealingflange96 includes apermanent sealant102 that creates a bond with theside panel12, as shown inFIG. 10b.
• When thereclosable package10 is opened for the first time, the sealingflange96 separates from the remaining portions of themale closure profile28 along the line ofweakness100 to provide access to theopen interior16. Thepermanent sealant102 is sufficiently strong to cause the separation of the sealingflange96 from themale closure profile28 upon initial opening. In the embodiment shown inFIGS. 10a-10c, thepermanent sealant102 is the same composition as thesealant46 shown in the first embodiment ofFIG. 1a.
• Referring now toFIGS. 11a-11b, thereshown is yet another embodiment of azipper closure104. In the embodiment of the invention shown inFIG. 11a, thezipper closure104 includes amale profile element106 and afemale profile element108. Themale profile element106 includes anattachment flange110 while the female profile element includes asimilar attachment flange112. As illustrated, theattachment flanges110,112 are joined to each other along an apex114. In the preferred embodiment of the invention, the apex114 includes a line of weakness such that theattachment flange110 can separate from theattachment flange112 along the apex114.
• As illustrated inFIG. 11a, themale profile element106 is initially attached to theside panel12 by the application of heat or an adhesive while thefemale closure profile108 is spaced from theside panel14 by theopening95. In this mated, spaced condition, product can be inserted into theopen interior16 of thereclosable package10 throughopening95 and past thezipper closure104. Once the product has been inserted, thefemale profile element108 is attached to theside panel14 by the application of heat or an adhesive to provide a seal across the mouth of the package. In the preferred embodiment of the invention, the male andfemale profile elements106,108 are extruded as one piece and are joined to each other along the apex114. During initial product opening, the male andfemale profile elements106,108 separate from each other along the apex114 to provide access to the open bag interior.
• FIGS. 12a-12cillustrate yet another embodiment of azipper closure26 positioned at the open mouth of thereclosable package10. In the embodiment illustrated inFIG. 12a, themale closure profile28 includes anattachment flange116 while thefemale closure profile30 includes asimilar attachment flange118. The attachment flanges116 and118 are not adhered to theside panels12,14 and each include areleasable sealant120.
• As illustrated inFIG. 12b, when thepackage10 is closed, thereleasable sealants120 engage each other to provide a hermetic seal across the entire width of thepackage10. In the preferred embodiment of the invention, thereleasable sealant120 is an FDA approved releasable sealant.
• As shown inFIG. 12c, when thepackage10 is opened for the first time, thereleasable sealant120 formed on each of theattachment flanges118 and116 separate to provide access to the open interior of theproduct package10.
• FIGS. 13a-13cillustrate yet another embodiment of the present invention for the creation of areclosable package10 that can withstand the retort process. As illustrated, theside panel12 includes afirst sealant strip122 while thesecond side panel14 includes asecond sealant strip124. The sealant strips122 and124 are aligned with each other such that when thereclosable package10 has been filled, the sealant strips122 and124 are brought into a mating relationship, as shown inFIG. 13b. The interaction between the sealant strips122 and124 provide a continuous seal across the interior of thereclosable package10 and prevents product from migrating past the sealant strips into contact with thezipper closure26.
• As shown inFIG. 13c, when thepackage10 is opened for the first time, the sealant strips122 and124 separate from each other to provide access to theopen interior16 of thepackage10. In the preferred embodiment of the invention, the sealant strips122 and124 create a peel seal and are formed from the same releasable sealant as described above.
• FIGS. 14a-14cshow alternate methods for attaching yet another zipper closure across the open mouth of areclosable package10. As illustrated inFIG. 14a, the zipper closure includes amale closure profile28 and afemale closure profile30. Themale closure profile28 includes a sealingflange126. The sealingflange126 includes a heatresistant layer128 formed on theback surface130. Areleasable sealant132 is formed on theopposite surface133 of the sealingflange126. The zipper closure shown inFIG. 14 is configured to allow product to be filled through the zipper and into the open interior of the package.
• FIG. 14billustrates the same zipper closure as shown inFIG. 14aexcept installed in an alternate manner. As illustrated inFIG. 14b, the male and female closure profiles28,30 are initially engaged with each other and the female closure profile attached to theside panel12 through the application of either heat or the use of an adhesive. In this condition, product can be inserted into theopen interior16 of the package through theopening95 between theback face surface135 of themale profile element28 and theside panel14. As illustrated, theback surface135 of themale closure profile28 includes lines ofadhesive134. The lines of adhesive134 bond with theside panel14 through the application of heat to adhere the zipper closure across the open mount of the reclosable package.
• As illustrated inFIG. 14c, thereleasable sealant132 attaches to theside panel12 while the layer of heatresistant material130 prevents attachment of the sealingflange126 to theside panel14.
• Upon opening thereclosable package10 for the first time, the sealingflange126 separates from theside panel12 along thereleasable sealant132. Alternatively, the sealingflange126 can include a line of weakness such that the sealingflange126 separates from the remaining portion of themale closure profile28 during the initial opening.
• FIGS. 15a-15cillustrate yet another embodiment of thezipper closure26. In the embodiment shown inFIG. 15a, themale closure profile28 includes a dependingsealing flange136. The sealingflange136 is separated from remaining portions of themale closure profile28 by a line ofweakness138, as shown inFIG. 15b. Referring back toFIG. 15a, the sealingflange136 includesmultiple ribs140 formed from a permanent sealant. Theribs140 form a bond with theside panel12 when thepackage10 is closed, as shown inFIG. 15b.
• Referring back toFIG. 15a, the opposite face surface of the sealing flange includes a series ofribs142 formed from a non-sealing material. Theribs142 prevent the sealingflange136 from becoming attached to theside panel14 when thereclosable package10 is closed, as shown inFIG. 15b.
• When thepackage10 is initially opened, the sealingflange136 separates from the remaining portions of themale closure profile28 along the line ofweakness138. Thus, when the package is initially opened, the sealingflange136 remains attached to theside panel12 as illustrated inFIG. 15c.
• As can be understood by the description of the alternate embodiments shown inFIGS. 1-15, the zipper closure positioned along the open mouth of the reclosable package allows the opposite side panels to be mated together to close the package. Each of the alternate embodiments illustrated includes a sealing flange or similar element that extends across the open interior of the reclosable package to prevent product from migrating into contact with the closure elements of the mating male and female closure profiles28,30. In each embodiment of the invention, the male and female closure profiles are formed from a polypropylene material that is bonded to thepolypropylene side panels12 and14. The materials used to form the zipper closure and side panels can withstand the temperatures associated with the retort process, as clearly described above. The embodiments illustrated inFIGS. 1-15 allow for top filling of the package either through the closure profiles or past the closure profiles, as described. Once the product package is filled, the top edge of the package is sealed to create a package that can withstand the retort process.
• Referring now toFIG. 16a, thereshown is another alternate embodiment of the zipper closure, as referred to byreference numeral70. Thezipper closure70 includes amale closure profile72 and afemale closure profile74. The male and female closure profiles72 and74 each include anattachment flange76 that is joined to therespective side panel12,14 of the reclosable package in the manner previously described.
• Referring now toFIG. 16b, both of the male and female closure profiles72 and74 are joined to each other by connectingflanges78 and80. The connectingflanges78 and80 are joined to each other along a line of weakness, such as a foldeddie line82 that defines a weakened portion of thezipper closure70.
• As illustrated inFIG. 16a, the reclosable package has an openbottom end84 through which product can be bottom filled into thereclosable package10. The interconnection of theconnector flanges78 and80, as well as the attachment of the male and female closure profiles72,74 to theside panels12 and14, provides a hermetic seal at the top of thepackage10 below the male and female closure posts.
• Referring now toFIG. 17,product50 can be inserted into thepackage10 through the openbottom end84. After theproduct50 has been inserted into the package, theside panels12 and14 are heat sealed to each other along a sealing joint86 (FIG. 18) to define the package. Once thebottom end84 has been sealed along the joint86, the package is subjected to the retort procedure, inverted and shipped to a consumer.
• Upon receipt, the consumer can grasp the top tear offheader88 which is separated from theside panels12 and14 along a pair of lines ofperforation90 and92 shown inFIG. 18. Upon grasping the top tear offheader88, the user can remove the top tear offheader88 as illustrated inFIG. 19.
• Once the top tear offheader88 has been removed, the user can grasp the grippingstrips60 formed on themale closure profile72 and thefemale closure profile74 and pull theprofiles72,74 apart until themale closure post32 separates from the pair of female closure posts36 and38, as illustrated inFIG. 20. As illustrated inFIG. 20, thedie line82 between the connectingflanges78 and80 provides a seal upon the initial separation of the interlocking profiles.
• As with the first embodiment of the invention previously described, the connection between theflanges78 and80 prior to product being inserted into the package and subjected to the retort procedure prevents the product from migrating through the interlocking members of the zipper closure. Thus, upon initial opening of the package, the user can grasp themale closure profile72 and thefemale closure profile74 without any product being present.
• As illustrated inFIG. 21, if the user further pulls the male and female closure profiles72 and74 apart, the connectingflanges78 and80 separate to provide access to theproduct50 contained within the reclosable package. In this manner, the male and female closure profiles72,74 provide not only a seal to prevent product migration past the zipper closure, but also provide a tamper evident feature to the reclosable package.
• FIG. 22 illustrates an alternate embodiment of thezipper closure70 for a bottom filled package. In the embodiment shown inFIG. 22, themale closure profile72 and thefemale closure profile74 are joined to each other by amembrane144. Themembrane144 includes a first end146 coupled to themale closure profile72 and a second end148 coupled to thefemale closure profile74. In the preferred embodiment of the invention, themembrane144 has a material strength less than the strength of the bond between the male and female closure profiles72,74 and theside panels12,14. Thus, during the initial opening of thereclosable package10, themembrane144 tears or ruptures to provide access to the open interior of thereclosable package10.
• In one contemplated embodiment of the invention, the first and second ends146,148 of themembrane144 are adhesively attached to the male and female closure profiles72,74. However, it is contemplated that themembrane144 could be co-extruded with the male and femaleclosure profile elements72 and74. In either case, the bond between the first and second ends146,148 of themembrane144 to the male and female closure profiles72,74 must be greater than the material strength of themembrane144 such that themembrane144 tears upon initial opening of the product package. Additionally, themembrane144 must be selected such that it is impermeable to the product contained within thereclosable package10 to prevent the product from migrating into contact with the closure elements of the zipper closure.
• FIG. 23 illustrates yet another embodiment of thezipper closure70 particularly useful with a bottom-fill reclosable package10. In the embodiment shown inFIG. 23, the male and female closure profiles72,74 each include a dependingattachment flange150,152. The attachment flanges each include areleasable sealant154,156 such that theattachment flanges150,152 can be joined to each other along thereleasable sealants154,146. During initial opening of the product package, theattachment flanges150,152 separate from each other through the separation of the releasable sealant layers154,156. Preferably, thereleasable sealant154,156 is an FDA approved sealant.
• FIG. 24 illustrates yet another alternate embodiment of thezipper closure70 for use with a bottom-fill reclosable package. In the embodiment illustrated inFIG. 24, themale closure profile72 includes anextended sealing flange154 that extends across the open interior of the package from theside panel12 to theside panel14. The sealingflange154 includes areleasable adhesive156 that holds the sealingflange154 in contact with theside panel14.
• During initial opening of the package, the sealingflange154 separates from theside panel14 along thereleasable adhesive156. In the preferred embodiment of the invention, thereleasable adhesive156 is an FDA approved sealant.
• FIG. 25 illustrates another alternate embodiment for thezipper closure70 for use with a bottom-fill reclosable package. As illustrated inFIG. 25, amembrane158 extends across the open package interior from themale closure profile72 to theside panel14. Themale closure profile72 includes anextended attachment flange160. Theextended attachment flange160 receives afirst end162 of themembrane158. Preferably, themembrane158 can be attached to theextended attachment flange160 through either a layer of adhesive or through a co-extrusion process. Thesecond end164 of themembrane158 includes areleasable sealant166 that allows themembrane158 to be removably attached to theside panel14.
• During initial opening of thepackage10 shown inFIG. 25, the bond between thereleasable adhesive166 and theside panel14 is destroyed to provide access to the open interior of the package. As can be understood, the bond between thefirst end162 of themembrane158 and theattachment flange160 is greater than the strength of thesealant166 such that the opening interior of the product package can be accessed.
• FIG. 26 illustrates yet another embodiment of the invention. The embodiment illustrated inFIG. 26 is similar to the embodiment illustrated inFIG. 24 and includes a sealingflange154 that extends from themale closure profile72. However, in the embodiment illustrated inFIG. 26, the sealingflange154 includes a line ofweakness168. Additionally, theend170 of the sealingflange154 is attached to theside panel14 by apermanent sealant172, rather than thereleasable sealant156 shown inFIG. 24.
• During initial opening of theproduct package10, including thezipper closure70 shown inFIG. 26, the sealingflange154 fractures along the line ofweakness168. The separation along the line ofweakness168 allows for access to the open interior of theproduct package10 including thezipper closure70 shown inFIG. 26. Thepermanent sealant172 shown inFIG. 26 is preferably the same sealant shown and described in the first embodiment of the invention shown inFIG. 1a.
• FIG. 27 illustrates yet another embodiment of thezipper closure70 for use with a bottom-fill reclosable package10. In the embodiment of the invention illustrated, the male closure profile and thefemale closure profile74 are joined to each other along a curved,center section174. Thecenter section174 includes a line ofweakness176 positioned somewhere along its length. The line ofweakness176 can be formed either during the extrusion process, or as a weakened area during subsequent processing of thezipper closure70. When thereclosable package10 is initially opened, themale closure profile72 separates from the female closure profile along the line ofweakness176.
• Referring now toFIG. 28, thereshown is yet another embodiment of thezipper closure70 of the present invention for a bottom-fill reclosable package. In the embodiment shown inFIG. 28, a first sealant strip is formed on theside panel12 and asecond sealant strip180 is formed on theopposite side panel14. Prior to filling of thepackage10, the sealant strips178 and180 are brought into contact with each other, as shown. The interaction between the sealant strips178 and180 prevents product from migrating into contact with the closure elements formed on themale closure profile72 and thefemale closure profile74.
• Once the product has been filled into the reclosable package and subjected to the retort process, the package can be stored. Upon initial opening, the male and femaleclosure profile elements72,74 are separated. Further separation results in the separation of the sealant strips178,180 to provide access to theopen interior16 of thepackage10. In the preferred embodiment of the invention, the sealant strips178,180 are formed from a releasable sealant.
• In the embodiments of the invention illustrated inFIGS. 16-28, the male and female closure profiles72 and74 are formed from the same material as the closure profiles described above in reference to the top filled package and zipper designs shown inFIGS. 1-15. Thus, the bottom filled reclosable packages illustrated inFIGS. 16-28 can be subjected to the retort procedure without negatively affecting the performance of the male and female closure profiles.
• Having described the presently preferred embodiments, it is to be understood that the invention may be otherwise embodied within the scope of the appended claims.

Claims (3)

1. A flexible, reclosable package for containing a product and allowing the product to be subjected to a retort process while within the reclosable package, comprising:

a pair of side panels joined along a first side edge and a second side edge, the side panels defining a mouth providing access to a package interior, wherein the side panels are formed from polypropylene; and

a reclosable zipper positioned along the mouth of the package for selectively opening and closing the package mouth, the reclosable zipper including a first closure profile attached to the first side panel and a second closure profile attached to the second side panel, wherein the first and second closure profiles are each constructed and arranged to interlock each other to hold the mouth in a closed position, wherein the reclosable zipper is formed from polypropylene,

wherein the first closure profile includes a sealing flange having a sealant, wherein the sealant of the sealing flange is attached to the second side panel opposite the first closure profile during the retort process to provide a hermetic seal between the sealing flange and the second side panel.

2. The reclosable package ofclaim 1 wherein the sealant is applied to a first face surface of the sealing flange and a heat resistant layer is applied to a second, opposite face surface of the sealing flange to prevent attachment of the sealing flange to the first side panel.

3. The reclosable package ofclaim 2 wherein the heat resistant layer is applied in a series of ribs along the second face surface of the sealing flange.

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