US20050035020A1

US20050035020A1 - Sealable bag having an integrated tray for use in vacuum packaging

Info

Publication number: US20050035020A1
Application number: US10/794,951
Authority: US
Inventors: Hongyu Wu; Charles Albritton; David Brakes
Original assignee: Tilia International Inc USA
Current assignee: Tilia International Inc USA
Priority date: 2003-03-05
Filing date: 2004-03-04
Publication date: 2005-02-17

Abstract

A bag for use in vacuum packaging comprises a first panel and a second panel overlapping each other. One or more trays for retaining a perishable or other product is formed on one or more of the panels. Each tray can optionally have ridges for suspending a product above the tray so that liquid can collect in the tray. 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.

Description

PRIORITY CLAIM

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

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. 60/452,171, 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. 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); and
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 “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;
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; and
U.S. patent application Ser. No. ______, entitled “METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED TIMER/SENSOR FOR USE IN VACUUM PACKAGING,” Attorney Docket No. TILA-01182US3, 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 apart 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. 2A is a plan view of a panel in accordance with one embodiment of the present invention, manufactured by the process shown in FIG. 1A-1C;
FIG. 2B is a cross-section view of a panel in accordance with one embodiment of the present invention, manufactured by the process shown in FIG. 1A-1C; and
FIG. 3 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 raised walls for preventing shifting of perishable or other product contained 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 heat-sealable 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 as that of the laminating roll 102.
The heat-sealable inner layer 106 is typically made of a thermoplastic resin. For example, the 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 resin layers 106 of the two panels is brought into contact and heat is 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 away 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 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 forming raised walls defining one or more discrete trays. The pattern can also optionally include cavities (and/or protuberances) for forming ridges or protuberances within the raised walls for suspending a perishable or other product over a base of the trays, thereby allowing liquid to collect in the tray. The resin 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. The melt-extruded resin quickly cools and solidifies in the desired pattern 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 conventional methods adopting a post-embossing treatment where the heat-sealable inner layer is drawn by a die or embossed between male and female components.
FIG. 2A is a plan view of a panel 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 raised walls 232 are formed for defining a tray 230 for restricting the movement of perishable or other products. Within the raised walls 232 of the tray are ridges 234 for suspending the perishable or other products over the base of the tray. As shown, the ridges 234 are cross-hatched and form reservoirs 236 for liquid to collect. In other embodiments, the ridges can be formed in a multitude of different patterns, allowing for the formation of reservoirs 236 having a multitude of different shapes and sizes. In still other embodiments, the tray 230 can include protuberances, wherein the protuberances can be discrete pyramids, hemispheres, etc., thereby allowing liquid to collect evenly in the base of the tray 230. In still other embodiments, the panel 220 can include a plurality of discrete trays 230, each sized to suit an application and optionally having ridges 234 or protuberances. One of ordinary skill in the art can appreciate the myriad of different ways in which the panel 220 can be configured to restrict the movement of perishable products within a vacuum bag.
The thickness of the raised walls 232 and ridges 234 formed on the heat-sealable inner layer 106 of a panel 220 can be determined by the depth of the cavities of the cooling roll 104, and the width of the raised walls 232 and ridges 234 can be determined by the width of the cavities. Thus, the shape, width, and thickness of the raised walls 232 and ridges 234 can be controlled by changing the specifications for the cavities of the cooling roll 104. FIG. 2B is a cross-sectional view of the panel 220 described above. In the heat-sealable inner layer 106, the raised walls 232 can range, for example, from about 35-75 mils or more in height, the gas-impermeable base layer 108 can range, for example, from about 0.5-8.0 mils in thickness, and the heat-sealable inner layer 106, can range, for example, from about 0.5-6.0 mils in thickness (without the raised walls 232). Optionally, ridges 234 or protuberances can by included. The ridges 234 or protuberances can have a height lower than the raised walls 232, thereby suspending the perishable or other product while still retaining the perishable product within the tray 230. For example, if the raised wall 232 is 75 mils in height, the height of the ridges 234 or protuberances can be about 30 mils. The dimensions of the raised walls 232, the ridges 234, the base layer 108, and the inner layer 106 are set forth to illustrate, but are not to be construed to limit the dimensions.
FIG. 3 illustrates a bag for use in vacuum packaging in accordance with one embodiment of the present invention. The vacuum bag 350 comprises a first panel 320 and a second panel 322 overlapping each other. At least one tray 230 is formed on the first panel 320 in accordance with an embodiment described above. The second panel 322 (or first panel 320) 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 resin layer 106 and the gas-impermeable base layer 108 of the first and second panels 320,322 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 resin 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 320,322 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 350, air and/or other gases can be evacuated from the bag 350, 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.

Claims

1. A bag adapted to receive an article, comprising:

a first panel defining a tray adapted to receive the article and a plurality of protuberances within the tray, which protuberances are adapted to support the article over a base of the tray;

a second panel; and

the first panel and the second panel secured together to form the bag.

2. The bag of claim 1 wherein said first panel is formed of a heat sealable material and said second panel is formed of a gas impermeable material.

3. A bag adapted to receive an article, comprising:

a first panel having:

a first outer layer; and

a first inner layer connected with the first outer layer, the first inner layer including at least one tray integrally formed with the first inner layer;

a second panel connected with the first panel such that the first panel and the second panel form an envelope having an inlet, the second panel having:

a second outer layer; and

a second inner layer connected with the second outer layer.

4. The bag of claim 3, further comprising a plurality of protuberances within the at least one trays.

5. The bag of claim 3, wherein the first outer layer and the second outer layer comprise a gas-impermeable material.

6. The bag of claim 5, wherein the gas-impermeable material is one of polyester, polyamide, ethylene vinyl alcohol, and nylon.

7. The bag of claim 3, wherein the first inner layer and the second inner layer comprise a thermoplastic resin.

8. The bag of claim 7, wherein the thermoplastic resin is polyethylene.

9. The bag of claim 5, wherein when the article is positioned within the tray, the article is supported by the plurality of protuberances.

10. The bag of claim 4, wherein when the article is positioned within the tray, the article is supported above a base of the at least one tray.

11. The bag of claim 4, wherein the plurality of protuberances define a plurality of pockets formed such that liquid can collect in the plurality of pockets; and

wherein when the article is positioned within the tray, the article is positioned above liquid collected in the plurality of pockets.

12. A bag adapted to receive an article, comprising:

a first panel including:

a first gas-impermeable layer; and

a first inner layer laminated to the first gas-impermeable layer, the first inner layer including at least one tray integrally formed with the first inner layer;

a second panel including:

a second gas-impermeable layer; and

a second inner layer laminated to the second gas-impermeable layer; and

wherein the first panel is connected with the second panel to form an envelope such that the first inner layer opposes the second inner layer, the envelope including a heat-sealable opening for evacuating gas.

13. The bag of claim 12, further comprising a plurality of protuberances within the at least one trays.

14. The bag of claim 12, wherein the first gas-impermeable layer and the second gas-impermeable layer comprise one of polyester, polyamide, ethylene vinyl alcohol, and nylon.

15. The bag of claim 12, wherein the first inner layer and the second inner layer comprise a thermoplastic resin.

16. The bag of claim 15, wherein the thermoplastic resin is polyethylene.

17. The bag of claim 13, wherein when the article is positioned within the tray, the article is supported by the plurality of protuberances.

18. The bag of claim 13, wherein when the article is positioned within the tray, the article is supported above a base of the at least one tray.

19. The bag of claim 13, wherein the plurality of protuberances define a plurality of pockets formed such that liquid can collect in the plurality of pockets; and

20. A heat-sealable bag adapted to receive an article, comprising:

a first panel including:

a first gas-impermeable layer;

at least one first intermediate layer connected with the first gas-impermeable layer; and

a first inner layer laminated to the at least one first intermediate layer, the first inner layer including at least one tray integrally formed with the first inner layer; and

a second panel including:

a second gas-impermeable layer;

at least one second intermediate layer connected with the second gas-impermeable layer; and

a second inner layer laminated to the at least one second intermediate layer;

21. The bag of claim 20, further comprising a plurality of protuberances within the at least one trays.

22. The bag of claim 20, wherein the first gas-impermeable layer and the second gas-impermeable layer comprise one of polyester, polyamide, ethylene vinyl alcohol, and nylon.

23. The bag of claim 20, wherein the first inner layer and the second inner layer comprise a thermoplastic resin.

24. The bag of claim 23, wherein the thermoplastic resin is polyethylene.

25. The bag of claim 21, wherein when the article is positioned within the tray, the article is supported by the plurality of protuberances.

26. The bag of claim 21, wherein when the article is positioned within the tray, the article is supported above a base of the at least one tray.

27. The bag of claim 21, wherein the plurality of protuberances define a plurality of pockets formed such that liquid can collect in the plurality of pockets; and