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Publication numberUS20050043158 A1
Publication typeApplication
Application numberUS 10/794,373
Publication dateFeb 24, 2005
Filing dateMar 4, 2004
Priority dateMar 5, 2003
Publication number10794373, 794373, US 2005/0043158 A1, US 2005/043158 A1, US 20050043158 A1, US 20050043158A1, US 2005043158 A1, US 2005043158A1, US-A1-20050043158, US-A1-2005043158, US2005/0043158A1, US2005/043158A1, US20050043158 A1, US20050043158A1, US2005043158 A1, US2005043158A1
InventorsHongyu Wu, Charles Albritton, David Brakes
Original AssigneeTilia International, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method for manufacturing a sealable bag having an integrated timer/sensor for use in vacuum packaging
US 20050043158 A1
Abstract
A method for manufacturing a bag for use in vacuum packaging comprises forming a first panel having an embedded timer and/or sensor for communicating information to a user and a second panel. Each panel comprises a gas-impermeable base layer and a heat-sealable inner layer molded from melt-extruded resin. The timer and/or can be encapsulated in the resin, or alternatively impregnated into the resin. The first panel is overlapped with the second panel, and three of four edges of the panels are heated such that the inner layers bond at the heated edges. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.
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Claims(33)
1. A method for forming a panel for use in a sealable bag; comprising:
flowing a material onto a backing film, such that the flowing material is molded to form a structure;
wherein at least one of a timer and a sensor is formed in the structure;
cooling the flowing material such that the flowing material solidifies to form an inner layer having the structure; and
wherein the inner layer adheres to the backing film.
2. A method for forming a bag adapted to receive an article, the bag being partially formed between a laminating roll and a cooling roll having at least one cavity for positioning an implant including at least one of a timer and a sensor, comprising:
positioning the implant in the at least one cavity of the cooling roll;
feeding a gas-impermeable film to a nip formed by the cooling roll and the laminating roll;
extruding resin such that the resin fills the nip and the at least one cavity exposed to the nip;
pressing the resin between the cooling roll and the laminating roll;
cooling the resin such that the resin forms a structure and adheres to the gas-impermeable film, forming a panel;
wherein the structure includes the implant;
folding the panel such that a first portion of the panel overlaps a second portion of the panel; and
applying heat to a portion of a periphery of the first and second portions such that an envelope is formed.
3. A method for manufacturing a bag adapted to receive an article, comprising:
positioning an implant including at least one of a timer and a sensor in at least one cavity of a first cooling roll;
feeding a first gas-impermeable film to a first nip formed by the first cooling roll and a first laminating roll;
extruding resin such that the resin fills the first nip and the at least one cavity exposed to the first nip;
pressing the resin between the first cooling roll and the first laminating roll;
cooling the resin such that a first inner layer having the implant is formed;
wherein the first inner layer adheres to the first gas-impermeable film, thereby forming a first panel;
feeding a second gas-impermeable film to a second nip formed by a second cooling roll and a second laminating roll;
extruding resin such that the resin fills the second nip and the plurality of cavities exposed to the second nip;
pressing the resin between the second cooling roll and the second laminating roll;
cooling the resin such that a second inner layer having the second structure is formed;
wherein the second inner layer adheres to the first gas-impermeable film, thereby forming a second panel;
overlapping the first panel with the second panel; and
applying heat to a first, second, and third side of the first and second panels.
4. A method for manufacturing a bag adapted to receive an article, comprising:
rotating a first cooling roll at a first rate, the first cooling roll including at least one cavity for forming a structure;
positioning an implant including at least one of a timer and a sensor in the at least one cavity;
rotating a first laminating roll at a second rate;
introducing a first film to a first nip between the first cooling roll and the first laminating roll;
extruding molten material to the first nip;
pressing the molten material between the first cooling roll and the first film such that the molten material fills the at least one cavity exposed to the first nip;
cooling the molten material such that a first inner layer is formed;
wherein the first inner layer includes the structure, the structure including the implant;
wherein the first inner layer adheres to the first film, thereby forming a first panel;
rotating a second cooling roll at a third rate;
rotating a second laminating roll at a fourth rate;
introducing a second film to a second nip between the second cooling roll and the second laminating roll;
extruding molten material to the second nip;
pressing the molten material between the second cooling roll and the second film;
cooling the molten material such that a second inner layer is formed;
wherein the second inner layer adheres to the second film, thereby forming a second panel;
overlapping the first panel with the second panel; and
applying heat to a portion of a periphery of the first and second panels such that the first panel and the second panel form an envelope.
5. The method of claim 4, wherein the second rate is an integer multiple of the first rate and the fourth rate is an integer multiple of the third rate.
6. The method of claim 4, wherein the first film and the second film comprise at least one layer.
7. The method of claim 6, wherein the at least one layer comprises a gas-impermeable material.
8. The method of claim 7, wherein the gas-impermeable material is one of polyester, polyamide, ethylene vinyl alcohol, and nylon.
9. The method of claim 4, wherein the molten material is polyethylene.
10. The method of claim 4, wherein a thickness of the first inner layer is determined by the size of the first nip and the thickness of the second inner layer is determined by the size of the second nip.
11. The method of claim 4, wherein the implant includes at least one timer.
12. The method of claim 11, wherein the at least one timer is an active radio frequency identification tag.
13. The method of claim 4, wherein the implant includes at least one sensor.
14. The method of claim 13, wherein the at least one sensor is a temperature sensor.
15. The method of claim 13, wherein the at least one sensor is a temperature sensor.
16. The method of claim 4, wherein the first inner layer includes UV activated chemicals.
17. The method of claim 16, wherein the UV activated chemical is one or both of silver chloride and silver halide.
18. The method of claim 4, wherein the first inner layer includes at least one chemical for preserving the article.
19. The bag of claim 18, wherein the chemical is potassium permanganate.
20. A method of manufacturing a bag adapted to receive an article, comprising:
rotating a first roller having one or both of a plurality of recesses that can define at least one structure;
positioning an implant including at least one of a timer and a sensor in the plurality of recesses;
rotating a second roller adjacent to the first roller, said second roller can feed a first film adjacent to the first roller;
applying a molten material between the first roller and the first film;
said molten material filling the plurality of recesses of the first roller and said molten material and film moving between the first roller and the second roller forming a first panel with the structure having the implant;
forming a second panel; and
mating the first panel to the second panel in order to form a bag.
21. The method of claim 20 further comprising:
using a gas impermeable material for the film; and
using a heat sealable material for the molten material.
22. The method of claim 20, wherein said second panel is formed with the first roller and the second roller.
23. The method of claim 20, wherein said second panel is formed with the first roller and the second roller, and the mating step includes folding the first panel over the second panel.
24. The method of claim 20, wherein the implant includes at least one timer.
25. The method of claim 24, wherein the at least one timer is an active radio frequency identification tag.
26. The method of claim 20, wherein the implant includes at least one sensor.
27. The method of claim 26, wherein the at least one sensor is a temperature sensor.
28. The method of claim 26, wherein the at least one sensor is a temperature sensor.
29. The method of claim 20, wherein the first inner layer includes UV activated chemicals.
30. The method of claim 29, wherein the UV activated chemical is one or both of silver chloride and silver halide.
31. The method of claim 20, wherein the first inner layer includes at least one chemical for preserving the article.
32. The bag of claim 31, wherein the chemical is potassium permanganate.
33. A method for manufacturing a bag adapted to receive an article, comprising:
feeding a first gas-impermeable film to a first nip formed by a first cooling roll and a first laminating roll, the first cooling roll having a plurality of cavities and protuberances for forming a first structure and a second structure;
wherein the first structure is one of a receiving feature and an insertion feature;
wherein the second structure is a valve;
extruding resin such that the resin fills the first nip and the plurality of cavities exposed to the first nip;
pressing the resin between the first cooling roll and the first laminating roll;
cooling the resin such that a first inner layer having the first structure and the second structure is formed;
wherein the first inner layer adheres to the first gas-impermeable film, thereby forming a first panel;
feeding a second gas-impermeable film to a second nip formed by a second cooling roll and a second laminating roll, the second cooling roll having a plurality of cavities and protuberances for forming a third structure;
wherein the third structure is the other of the receiving feature and the insertion feature;
extruding resin such that the resin fills the second nip and the plurality of cavities exposed to the second nip;
pressing the resin between the second cooling roll and the second laminating roll;
cooling the resin such that a second inner layer having the third structure is formed;
wherein the second inner layer adheres to the first gas-impermeable film, thereby forming a second panel;
overlapping the first panel with the second panel; and
applying heat to a first, second, and third side of the first and second panels.
Description
PRIORITY CLAIM

This application claims priority to the following U.S. Provisional Patent Application:

U.S. Provisional Patent Application No. 60/452,139, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED TIMER/SENSOR FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01182US1).

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This U.S. Patent Application incorporates by reference all of the following co-pending applications:

U.S. Provisional Patent Application No. 60/452,168, entitled “LIQUID-TRAPPING BAG FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01177US0);

U.S. Provisional Patent Application No. 60/452,138, entitled “METHOD FOR MANUFACTURING LIQUID-TRAPPING BAG FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01177US1);

U.S. Provisional Patent Application No. 60/452,172, entitled “SEALABLE BAG HAVING AN INTEGRATED TRAY FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01178US0);

U.S. Provisional Patent Application No. 60/452,171, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED TRAY FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01178US1);

U.S. Provisional Patent Application No. 60/451,954, entitled “SEALABLE BAG HAVING AN INDICIA FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01179US0).

U.S. Provisional Patent Application No. 60/451,948, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INDICIA FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01179US1);

U.S. Provisional Patent Application No. 60/452,142, entitled “SEALABLE BAG HAVING AN INTEGRATED ZIPPER FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01180US0);

U.S. Provisional Patent Application No. 60/452,021, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED ZIPPER FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01180US1);

U.S. Provisional Patent Application No. 60/451,955, entitled “SEALABLE BAG HAVING AN INTEGRATED VALVE STRUCTURE FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01181US0);

U.S. Provisional Patent Application No. 60/451,956, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED VALVE STRUCTURE FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01181US1);

U.S. Provisional Patent Application No. 60/452,157, entitled “SEALABLE BAG HAVING AN INTEGRATED TIMER/SENSOR FOR USE IN VACUUM PACKAGING,” by Henry Wu, et al., filed Mar. 5, 2003 (Attorney Docket No. TILA-01182US0);

U.S. patent application Ser. No. 10/169,485, entitled “METHOD FOR PREPARING AIR CHANNEL EQUIPPED FILM FOR USE IN VACUUM PACKAGE,” filed Jun. 26, 2002;

U.S. patent application Ser. No. ______, entitled “LIQUID-TRAPPING BAG FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01177US2, filed concurrently;

U.S. patent application Ser. No. ______, entitled “METHOD FOR MANUFACTURING LIQUID-TRAPPING BAG FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01177US3, filed concurrently;

U.S. patent application Ser. No. ______, entitled “SEALABLE BAG HAVING AN INTEGRATED TRAY FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01178US2, filed concurrently;

U.S. patent application Ser. No. ______, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED TRAY FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01178US3, filed concurrently;

U.S. patent application Ser. No. ______, entitled “SEALABLE BAG HAVING AN INDICIA FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01179US2, filed concurrently;

U.S. patent application Ser. No. ______, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INDICIA FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01179US3, filed concurrently;

U.S. patent application Ser. No. ______, entitled “SEALABLE BAG HAVING AN INTEGRATED ZIPPER FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01180US2, filed concurrently;

U.S. patent application Ser. No. ______, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED ZIPPER FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01180US3, filed concurrently;

U.S. patent application Ser. No. ______, entitled “SEALABLE BAG HAVING AN INTEGRATED VALVE STRUCTURE FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01181US2, filed concurrently;

U.S. patent application Ser. No. ______, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED VALVE STRUCTURE FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01181US3, filed concurrently; and

U.S. patent application Ser. No. ______, entitled “SEALABLE BAG HAVING AN INTEGRATED TIMER/SENSOR FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01182US2, filed concurrently.

FIELD OF THE INVENTION

The present invention relates to bags for use in vacuum packaging and methods and devices for manufacturing bags for use in vacuum packaging.

BACKGROUND

Methods and devices for preserving perishable foods such as fish and meats, processed foods, prepared meals, and left-overs, and non-perishable items are widely known, and widely varied. Foods are perishable because organisms such as bacteria, fungus and mold grow over time after a food container is opened and the food is left exposed to the atmosphere. Most methods and devices preserve food by protecting food from organism-filled air. A common method and device includes placing food into a gas-impermeable plastic bag, evacuating the air from the bag using suction from a vacuum pump or other suction source, and tightly sealing the bag.

A bag for use in vacuum packaging can consist of a first panel and second panel, each panel consisting of a single layer of heat-sealable, plastic-based film (for example, polyethylene). The panels are sealed together along a substantial portion of the periphery of the panels by heat-sealing techniques so as to form an envelope. Perishable products, such as spoilable food, or other products are packed into the envelope via the unsealed portion through which air is subsequently evacuated. After perishable products are packed into the bag and air is evacuated from the inside of the bag, the unsealed portion is heated and pressed such that the panels adhere to each other, sealing the bag.

U.S. Pat. No. 2,778,173, incorporated herein by reference, discloses a method for improving the evacuation of air from the bag by forming channels in at least one of the panels with the aid of embossing techniques. Air escapes from the bag along the channels during evacuation. The embossing forms a pattern of protuberances on at least one of the panels. The protuberances can be discrete pyramids, hemispheres, etc., and are formed by pressing a panel using heated female and male dies. The first panel is overlaid on the second panel such that the protuberances from one panel face the opposite panel. The contacting peripheral edges of the panels are sealed to each other to form an envelope having an inlet at an unsealed portion of the periphery. The perishable or other products are packed into the envelope through the inlet, and the inlet is sealed. Thereafter, an opening is pierced in a part of the panel material that communicates with the channels, air is removed from the interior of the envelope through the channels and opening, and the opening is sealed. This type of bag requires two additional sealing steps after the perishable or other product is packed into the envelope. One further problem is that embossing creates impressions on the plastic such that indentations are formed on the opposite side of the panel

To avoid additional sealing steps, a vacuum bag is formed having a first panel and a second panel consisting of laminated films. Each panel comprises a heat-sealable inner layer, a gas-impermeable outer layer, and optionally, one or more intermediate layers. Such a bag is described in U.S. Pat. No. Re. 34,929, incorporated herein by reference. At least one film from at least one panel is embossed using an embossing mold to form protuberances and channels defined by the space between protuberances, so that air is readily evacuated from the vacuum bag.

U.S. Pat. No. 5,554,423, incorporated herein by reference, discloses still another bag usable in vacuum packaging. The bag consists of a first and second panel, each panel consisting of a gas-impermeable outer layer and a heat-sealable inner layer. A plurality of heat-sealable strand elements are heat bonded at regular intervals to the inner layer of either the first panel or the second panel. The spaces between strand elements act as channels for the evacuation of air. The strand elements are extruded from an extrusion head and heat bonded to the heat-sealable layer by use of pressure rolls. Separate equipment is required for producing strand elements, and a procedure of heat bonding a plurality of strand elements at regular intervals to the heat-sealable inner layer is complicated. Also, various shapes of pattern are hard to form using this process.

BRIEF DESCRIPTION OF THE FIGURES

Further details of embodiments of the present invention are explained with the help of the attached drawings in which:

FIG. 1A is a perspective view of a method for manufacturing a vacuum bag in accordance with one embodiment of the present invention;

FIG. 1B is a side view of the method shown in FIG. 1A illustrating the embossing method used in an embodiment of the present invention;

FIG. 1C is a close-up view of a portion of FIG. 1B;

FIG. 2 is a plan view of an exemplary timer/sensor on a panel in accordance with embodiments of the present invention, manufactured by the process shown in FIGS. 1A-1C;

FIG. 3 is a cross-section of a portion of a panel as illustrated in FIG. 2, according to an embodiment of the present invention; and

FIG. 4 is a perspective view of a vacuum bag in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION

FIGS. 1A-1C illustrate one embodiment of a method for manufacturing a vacuum bag in accordance with the present invention. The vacuum bag comprises a first panel and a second panel, wherein each panel comprises a gas-impermeable base layer 108 and a heat-sealable inner layer 106 with at least one panel having a timer and/or sensor embedded inside the vacuum bag. A laminating roll 102 and a cooling roll 104 are arranged so that the heat-sealable inner layer 106 can be laminated to the gas-impermeable base layer 108 as the melt-extruded resin is cooled. As illustrated in FIG. 1C, the gap between the laminating roll 102 and the cooling roll 104 can be controlled according to specifications (for example, thickness) of a panel for use in vacuum packaging. The temperature of the cooling roll 104 is maintained in a range such that the melt-extruded resin is sufficiently cooled to form the desired pattern. For example, a temperature range of about −15° C. to about −10° C. can be sufficient to properly form the desired pattern. The temperature range of the cooling roll 104 can vary according to the composition of the resin, the composition of the gas-impermeable base layer 108, environmental conditions, etc. and can require calibration. Also, the cooling roll 104 can be sized to have a larger diameter than the laminating roll 102, thereby bringing the melt-extruded resin into contact with more cooled surface area. For example, the diameter of the cooling roll 104 can be about one-and-a-half to about three times as large (or more) as that of the laminating roll 102.

The heat-sealable inner layer 106 typically comprises a thermoplastic resin. For example, the melt-extruded resin can be comprised of polyethylene (PE) suitable for preserving foods and harmless to a human body. A vacuum bag can be manufactured by overlapping two panels such that the heat-sealable inner layers 106 of the two panels can be brought into contact and heat can be applied to a portion of the periphery of the panels to form an envelope. The thermoplastic resin can be chosen so that the two panels strongly bond to each other when sufficient heat is applied.

The gas-impermeable base layer 108 is fed to the gap between the cooling roll 104 and the laminating roll 102 by a feeding means (not shown). The gas-impermeable base layer can be comprised of polyester, polyamide, ethylene vinyl alcohol (EVOH), nylon, or other material having similar properties and capable of being used in this manufacturing process, and also capable of being heated. The gas-impermeable base layer 108 can consist of one layer, or two or more layers. When employing a multilayer-structured base layer, it should be understood that a total thickness thereof is also adjusted within the allowable range for the total gas-impermeable base layer 108.

An extruder 110 is positioned in such a way that the melt-extruded resin is layered on the gas-impermeable base layer 108 by feeding the melt-extruded resin to the nip between the cooling roll 104 and the gas-impermeable base layer 108. The resin is fed through a nozzle 112 of the extruder 110. The temperature of the melt-extruded resin is dependent on the type of resin used, and can typically range from about 200° C. to about 250° C. The amount of resin to be extruded into the laminating unit 100 is dependent on the desired thickness of the heat-sealable inner layer 106.

A pattern fabricated on the circumferential surface of the cooling roll 104 in accordance with one embodiment of the present invention can include cavities for suspending timers and/or sensors for encapsulation by melt-extruded resin. Timers and/or sensors 124 can be seeded in cavities of the cooling roll 104, for example by a label machine 114 attached to the extruder 110. The resin melt-extruded by the nozzle 112 is pressed between the cooling roll 104 and the gas-impermeable base layer 108 and flows into the cavities of the cooling roll 104 and surrounds the timers and/or sensors. The timer and/or sensor can be any device capable of communicating information to a user. For example, active radio frequency identification tags (RFID), such as the PowerID Smart Active Labels (SAL) system manufactured by Power Paper Ltd. of Israel, contain batteries and can be used as disposable timers. Sensors such as the PowerID SALs can be user activated, are thin and flexible, and low-cost, while at the same time are non-toxic in case of package penetration. Alternatively, the timer and/or sensor can be connected with the gas-impermeable base layer 108, for example by adhesives, before the gas-impermeable base layer 108 is fed to the cooling roll 104, thereby eliminating the need for cavities of the cooling roll 104. Alternatively, the sensor can be a temperature sensor having chemistry that can change color if exposed to specific temperatures for prolonged periods of time. In this way a user can estimate the freshness of packaged foods or other degradable products. The resin quickly cools and solidifies with the timer and/or sensor impregnated or embedded in the resin, while adhering to the gas impermeable base layer 108, thereby forming the heat-sealable inner layer 106 of the panel. The heat-sealable inner layer 106 can be formed while the resin is sufficiently heated to allow the resin to flow, thereby molding the resin, unlike other methods adopting a post-embossing treatment where the heat-sealable inner layer is drawn by a die or embossed between male and female components.

In other embodiments, chemicals such as silver chloride or silver halide, for example, can be added to the melt-extruded resin such that molecules of the chemicals are transparent to visible light in the absence of UV light (such as artificial light), thereby allowing the user to view the contents. When exposed to UV rays, as in direct sunlight, the molecules undergo a chemical process that causes them to change shape. The new molecular structure absorbs portions of the visible light, causing the film to darken. The number of molecules that change shape varies with the intensity of the UV rays. In this manner, contents of the vacuum bag can be protected from the harmful effects of UV rays. A laminated film formed by the heat-sealable inner layer 106 and gas-impermeable base layer 108 can be fed to a second cooling roll (not shown) for adding a second inner layer, thereby forming a barrier between the impregnated resin material and the packaged product.

In other embodiments, chemicals such as potassium permanganate, for example, can be added to the melt-extruded resin such that products that can spoil in the presence of ethylene can be preserved for a longer period as the ethylene is absorbed by the impregnated layer. A laminated film formed by the heat-sealable inner layer 106 and gas-impermeable base layer 108 can be fed to a second cooling roll for adding a second inner layer, thereby forming a barrier between the impregnated resin material and the packaged product that prevents chemicals from leaching into the product, while allowing ethylene gas to be absorbed through the barrier. One of ordinary skill in the art can appreciate the myriad different ways in which timers and/or sensors can be added to a vacuum bag.

FIG. 2 is a plan view of a panel 220 formed by the cooling roll 104 for use in a vacuum bag, in which the heat-sealable inner layer 106 is molded in such a way that a timer/sensor 124 is embedded in the heat-sealable inner layer 106. The timer/sensor 124 can be activated to measure the amount of time a product has been packed or stored. Optionally, a second timer/sensor 226 can be embedded in the heat-sealable inner layer 106 such that the temperature of the bag can be monitored. One of ordinary skill in the art can appreciate the different methods for monitoring the vacuum bag and the contents of the vacuum bag.

FIG. 3 is a cross-section of a portion of a panel 220 in accordance with one embodiment of the present invention. The heat-sealable inner layer 106, can range, for example, from about 0.5-4.0 mils in thickness between timers and/or sensors, while the gas-impermeable base layer 108 can range, for example, from about 0.5-8.0 mils in thickness. A second heat-sealable inner layer optionally added, can add an additional 0.5-4.0 mils in thickness.

The features and structures described above can be combined with other manufacturing techniques to form a valve or other structure, or tray, as described in the cross-referenced provisional applications, incorporated herein by reference. In other embodiments, the circumferential surfaces of the cooling rolls 104 described above can optionally include protuberances for forming perforations (not shown), such that a bag can be separated from a roll of bags by a customer.

FIG. 4 illustrates a bag for use in vacuum packaging in accordance with one embodiment of the present invention. The vacuum bag 450 comprises a first panel 220 and a second panel 422 overlapping each other. A timer and/or sensor is formed on the first panel 220 in accordance with an embodiment described above. The second panel 422 (or first panel 220) optionally includes channels (not shown) along a portion of the panel for evacuating air and other gases from the bag. The channels can be formed, for example, as described in the cross-referenced application “LIQUID-TRAPPING BAG FOR VACUUM PACKAGING,” incorporated herein by reference. The heat-sealable inner layer 106 and the gas-impermeable base layer 108 of the first and second panels 220,422 are typically made of the same material respectively, but can alternatively be made of different materials that exhibit heat-sealability and gas-impermeability respectively. As described above, the heat-sealable inner layer 106 is used as an inner layer and the gas-impermeable base layer 108 is used as an outer layer. The lower, left, and right edges of the first and the second panel 220,422 are bonded to each other by heating, so as to form an envelope for receiving a perishable or other product to be vacuum packaged. Once a perishable or other product is placed in the vacuum bag 450, air and/or other gases can be evacuated from the bag 450, for example by a vacuum sealing machine as described in U.S. Pat. No. 4,941,310, which is incorporated herein by reference. Once the air and/or other gases are evacuated to the satisfaction of the user, the inlet can be sealed by applying heat, thereby activating the heat-sealable inner layers 106 and bonding them together.

The foregoing description of preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to the practitioner skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalence.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7490452Jan 11, 2006Feb 17, 2009Unovo, Inc.Method and apparatus for evacuating and sealing containers
US7805913Sep 8, 2008Oct 5, 2010Unovo, Inc.Method and apparatus for evacuating and sealing containers
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Classifications
U.S. Classification493/162
International ClassificationB31B41/00, B65B61/02, B65B9/04, B65D81/20, B65D33/00
Cooperative ClassificationB65D33/004, B65B61/025, B31B2241/00, B65B9/042, B31B41/00, B65B2009/047, B65D81/2038
European ClassificationB31B41/00, B65D33/00E, B65B61/02B, B65D81/20B3, B65B9/04B
Legal Events
DateCodeEventDescription
Oct 29, 2004ASAssignment
Owner name: TILIA INTERNATIONAL, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:WU, HONGYU;ALBRITTON, CHARLES WADE;BRAKES, DAVID;REEL/FRAME:015940/0779
Effective date: 20041013