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. 60/452,142, 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);
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-b 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 “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.
The present invention relates to bags for use in vacuum packaging and methods and devices for manufacturing bags for use in vacuum packaging.
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.
Further details of embodiments of the present invention are explained with the help of the attached drawings in which:
FIGS. 2A-C are plan views of exemplary indicia on a panel in accordance with embodiments of the present invention, manufactured by the process shown in
The heat-sealable inner layer 106 typically comprises 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 inner layers 106 of the two panels are 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, and can be transparent so that indicia is visible through the gas-impermeable base layer 108. 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 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 protuberances and/or cavities or other pattern for forming indicia. The resin extruded from the nozzle 112 is pressed between the cooling roll 104 and the gas-impermeable base layer 108 and squeezed out where protuberances of the cooling roll 104 press into the resin, and/or the resin flows into the cavities of the cooling roll 104. The 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 220 as shown in
The depth (or thickness) of indicia formed on the heat-sealable inner layer 106 of a panel 220 can be determined by the height of the protuberances (or depth of the cavities) of the cooling roll 104. Thus, the shape, width, and depth (or thickness) of the indicia can be controlled by changing the specifications for the protuberances and/or cavities of the cooling roll 104.
The indicia 224 can also be used to improve a characteristic of the bag. For example, as shown in
In other embodiments, the indicia 224 can comprise a thermoplastic resin, wherein the thermoplastic resin is dyed or colored as desired so that the indicia is visually more apparent to a user. The colored indicia 224 can be applied to the surface, for example, in a separate manufacturing step. In one embodiment, shown in
In other embodiments, cavities and/or protuberances of the cooling roll 104 can include ink or dye so that indicia formed are colored by the ink or dye, while the melt-extruded resin surrounding the indicia is not colored by the ink or dye. The cavities and/or protuberances of the cooling roll 104 can be re-coated with ink or dye by a soft, saturated material mated to the cooling roll 104 as it rotates, thereby acting as an “inkpad” for the cooling roll 104. Alternatively, the ink or dye can be “sweated” into the cavities and/or protuberances through pores in the surface of the cavities and/or protuberances. One of ordinary skill in the art can appreciate the different methods for applying ink to grooves.
The features and structures described above can be combined with other manufacturing techniques to form a valve or other structure, tray, or integrated sensor, 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.
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 520,522 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 560, air and/or other gases can be evacuated from the bag 560, for example by a vacuum sealing machine as described in the above referenced 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 where contacted by the heat.
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. It is to be understood that 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.
This application claims priority to the following U.S. Provisional Patent Application: 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).
Number | Date | Country | |
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60451948 | Mar 2003 | US | |
60452168 | Mar 2003 | US | |
60452138 | Mar 2003 | US | |
60452172 | Mar 2003 | US | |
60452171 | Mar 2003 | US | |
60451954 | Mar 2003 | US | |
60452142 | Mar 2003 | US | |
60452021 | Mar 2003 | US | |
60451955 | Mar 2003 | US | |
60451956 | Mar 2003 | US | |
60452157 | Mar 2003 | US | |
60452139 | Mar 2003 | US |