Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D33/00—Details of, or accessories for, sacks or bags
  • B65D33/01—Ventilation or drainage of bags
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D2205/00—Venting means
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1324—Flexible food casing [e.g., sausage type, etc.]

Definitions

• This invention relates to packaging of the type suitable for use with food stuff to allow the food stuff to be cooked, say in a microwave oven, with the packaging still in place.
• Packaging of this type must form a sealed enclosure to contain the food stuff and prevent it from becoming contaminated during storage. Also, for convenience, it must be adapted to allow venting of steam from the sealed enclosure as the food stuff is cooked, without having to first pierce the packaging.
• Various venting arrangements have been provided for microwave packaging including wax plugs, weakened seals and leak paths which all vent at increased temperatures and/or pressures.
• An object of the present invention is to provide an improved packaging of the aforesaid type which is especially suitable for fresh foods.
• packaging comprises polymer film with portions of the film sealed together to form an enclosure for the food stuff, said sealed portions being sealed by a film-to-film seal except in a vent region where a lacquer layer is bonded to each portion of film before said portions are sealed together with the lacquer layers cohering, the seal strength of the lacquer-to-lacquer interface being similar to that of the film-to-film interface under predetermined storage conditions, and the seal strength of said lacquer-to-lacquer interface being reduced compared with that of the film-to-f ⁇ lm interface at temperatures above those expected under said predetermined storage conditions so that the enclosure is vented to atmosphere by a cohesive peel action in the vent region between said lacquer layers.
• Figure 1 illustrates packaging according to the invention
• Figure 2 shows a section through a vent seal of the packaging in Figure 1.
• the illustrated microwave packaging comprises a sheet 1 of Orientated Polypropylene (OPP) film which is folded on itself to bring together opposite edges which are heat sealed together along a back seal 2 to form a tube.
• OPP Orientated Polypropylene
• the lower open end of the tubular sheet is closed by bringing together opposite portions of the lower edge and heat sealing them together to form a lower seal 3.
• the packaging is then filled with food stuff and the open upper end closed by bringing together opposite portions of the upper edge and heat sealing them together to form an upper seal 4.
• a portion 5 of the upper seal 4 incorporates a lacquer-to-lacquer interface between the two portions of the sheet 1 so as to form a peelable seal which extends across the full width W of the seal 4.
• the lacquer is a coating 6 adhering to the inner face of each of the opposite portions of the sheet 1, which may be applied by a gravure or flexo printing process in advance of the sheet being formed into the final enclosure illustrated.
• the lacquer coating 6 comprises a colourless, coloured or opaque coating made up of resins or cellulose derivatives and a plasticizer in a solvent.
• the resin comprises a synthetic polymeric compound physically resembling natural resin, such as polyvinyl, polystyrene or epoxy.
• a preferred example comprises a composition of EVA based resins and a mixture of solvents comprising ethyl acetate, isopropyl acetate and hydrocarbon such as non-aromatic naptha.
• Such a lacquer is available as "Sovereign Proxseal J9683A" comprising an EVA copolymer dispersed in a solvent mix of ethyl acetate and aliphatic hydrocarbon.
• the properties of the seals are similar in strength at ambient, chill and freezer temperatures such as apply when the packaging is in use to store food stuff. Also, high humidity conditions caused by the food stuff within the packaging does not adversely affect the strength of the seal under ambient, chill and freezer conditions. High humidity conditions might comprise those up to 100% at 5-8 0 C, but typical humidity conditions comprise 85% or 95% at 5-8 0 C.
• the strength of that portion of the seal 5 incorporating the lacquer coatings 6 is significantly reduced at the elevated temperatures that are generated up to 100°C or above, the strength being only ⁇ 30g/25mm.
• This reduced strength of the lacquer-to-lacquer seal is such as to allow cohesive peeling, and provides an open vent path between the two portions of the OPP sheet to allow pressurised steam and gases to escape from within the packaging.
• the strength of the seal where the OPP sheet is sealed face-to-face without the intermediate lacquer coatings remains strong enough to hold the seal closed.
• venting of the packaging is controlled to occur only in the lacquer coated region 5 of the upper seal 4.
• the seal strength of the lacquer-to-lacquer is reduced significantly at temperatures of 60 0 C and above.
• the size of the lacquered vent region 5 is selected to give an appropriated vent cross-section. If required the vent region 5 could extend the full length of the seal 4. Alternatively, the position of the lacquered region 5 can be varied to suit the particular application and it may be located in one or more of the other seals 2 and 3. Alternatively, multiple vent regions 5 may be provided in one or more of the seams 2, 3, 4.
• the film may comprise any one of the following: polypropylene, polyethylene, polyester, polyamide, regenerated cellulose, polylactic acid, or combination of any of the preceding.
• the film may also comprise films with a heat seal coating.
• the film may be adapted for modified atmosphere packaging by forming microperforations in it which are small enough to control the oxygen/ carbon dioxide gas atmosphere within the bag.
• the food stuff will have a respiration rate which is matched to the natural permeability of the film and the additional permeability of the microperforations so as to produce the required modified atmosphere within the packaging.
• the total area of the microperforations would be too small to have any significant effect on the water vapour permeability of the film or the need to provide a separate vent.
• the lacquer may comprise a water-based EVA lacquer or an epoxy/ acrylic solvent based lacquer.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Packages (AREA)
• Wrappers (AREA)
• Orthopedics, Nursing, And Contraception (AREA)
• Laminated Bodies (AREA)
• Closures For Containers (AREA)
• Package Specialized In Special Use (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34930810

Family Applications (1)

Country Status (16)

Cited By (1)

Families Citing this family (9)

Citations (4)

Family Cites Families (3)

• 2004
  • 2004-11-18 SI SI200430796T patent/SI1659070T1/sl unknown
  • 2004-11-18 PT PT04257147T patent/PT1659070E/pt unknown
  • 2004-11-18 PL PL04257147T patent/PL1659070T3/pl unknown
  • 2004-11-18 AT AT04257147T patent/ATE395270T1/de active
  • 2004-11-18 DE DE602004013797T patent/DE602004013797D1/de not_active Expired - Lifetime
  • 2004-11-18 EP EP04257147A patent/EP1659070B1/en not_active Expired - Lifetime
  • 2004-11-18 DK DK04257147T patent/DK1659070T3/da active
  • 2004-11-18 ES ES04257147T patent/ES2273618T3/es not_active Expired - Lifetime
• 2005
  • 2005-11-15 US US11/719,655 patent/US20090202756A1/en not_active Abandoned
  • 2005-11-15 JP JP2007542088A patent/JP2008520510A/ja active Pending
  • 2005-11-15 NZ NZ555366A patent/NZ555366A/en not_active IP Right Cessation
  • 2005-11-15 WO PCT/GB2005/004393 patent/WO2006054060A1/en not_active Ceased
  • 2005-11-15 ZA ZA200704870A patent/ZA200704870B/xx unknown
  • 2005-11-15 CA CA2588510A patent/CA2588510C/en not_active Expired - Fee Related
  • 2005-11-15 BR BRPI0517755-3A patent/BRPI0517755A/pt not_active IP Right Cessation
  • 2005-11-15 AU AU2005305678A patent/AU2005305678B2/en not_active Ceased

Patent Citations (4)

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