EP0729900B1 - Verpackungs-Verfahren - Google Patents

Verpackungs-Verfahren Download PDF

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Publication number
EP0729900B1
EP0729900B1 EP19960102512 EP96102512A EP0729900B1 EP 0729900 B1 EP0729900 B1 EP 0729900B1 EP 19960102512 EP19960102512 EP 19960102512 EP 96102512 A EP96102512 A EP 96102512A EP 0729900 B1 EP0729900 B1 EP 0729900B1
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EP
European Patent Office
Prior art keywords
lid
tray
heat
temperature
axially oriented
Prior art date
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Expired - Lifetime
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EP19960102512
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English (en)
French (fr)
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EP0729900A2 (de
EP0729900A3 (de
Inventor
Jean Denis Sornay
Philippe Gomes Da Silva
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Cryovac LLC
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Cryovac LLC
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Priority to EP19960102512 priority Critical patent/EP0729900B1/de
Publication of EP0729900A2 publication Critical patent/EP0729900A2/de
Publication of EP0729900A3 publication Critical patent/EP0729900A3/de
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Publication of EP0729900B1 publication Critical patent/EP0729900B1/de
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    • 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
    • B65D77/00—Packages formed by enclosing articles or materials in preformed containers, e.g. boxes, cartons, sacks or bags
    • B65D77/10—Container closures formed after filling
    • B65D77/20—Container closures formed after filling by applying separate lids or covers, i.e. flexible membrane or foil-like covers
    • B65D77/2024—Container closures formed after filling by applying separate lids or covers, i.e. flexible membrane or foil-like covers the cover being welded or adhered to the container

Definitions

  • the present invention refers to an improved method for packaging goods, particularly food products, with plastics materials and to the package thus obtained.
  • plastics material bases such as thermoformed or injection moulded trays
  • packaging goods particularly in packaging food products.
  • the package is closed by applying a plastic lid on top of the tray which is then heat sealed to the tray rims.
  • a web of plastics material is provided over the top of the tray containing the product in a lid sealing station which comprises a lower chamber and an upper chamber.
  • the upper chamber includes a heated platen which may comprise one or more frames which, when the upper chamber and the lower chamber are closed together, press the lid(s) onto the rims or peripheral lips of the tray(s), in their turn supported by a similarly framed anvil, thus sealing them together.
  • the temperature at which the sealing frames are heated in order to seal the package depends on the machines and the materials used for the heat-sealing layers of both the tray and the lid. In general however temperatures between about 110 and about 160°C are suitable for any type of heat-sealing layer. Typically however temperatures of between about 120 and between about 140°C are employed.
  • Suitable cutting means finally allow the separation of the trays and the removal of excess plastics material from the lidstock web.
  • the platen which descends to heat-seal the lidstock to the flat top lips of the trays is wholly heated.
  • the plate is preferably covered with a non-sticky material such as a polytetrafluoroethylene (Teflon®) tape, to avoid problem of sticking of the film to the heated platen.
  • Teflon® polytetrafluoroethylene
  • a suitable gas or gas mixture which is used to enhance the shelf-life of the packaged goods (Modified Atmosphere Packaging).
  • This may be an inert gas, typically nitrogen, or another gas which will enhance the keeping qualities of the goods, such as carbon dioxide, mixture of two or more gases such as mixtures of carbon dioxide and nitrogen, of carbon dioxide and oxygen, or of oxygen, carbon dioxide and nitrogen in suitable proportions.
  • This modified atmosphere can be obtained by flushing the desired gas between the lid and the tray in the lid sealing station prior and until the package is sealed.
  • the modified atmosphere is obtained by closing the upper and lower chambers together, evacuating air through suitable air passageways which are indicated in Fig. 3 and 4 as (13), admitting the desired modified atmosphere into the closed upper and lower chambers so as to provide the desired modified atmosphere between the lid and the tray and then lowering the platen to seal the lid to the tray rims.
  • lid material which is relatively thick, is typically obtained by extrusion or coextrusion of the selected polymer(s) or polymer blends(s) by conventional methods which do not involve any orientation of the obtained thermoplastics sheet (so-called "cast” extrusion or coextrusion).
  • the lid material is produced by methods which do involve mono-axial or bi-axial orientation of the obtained sheet but - in addition thereto - also a heat-setting step of the oriented product.
  • the obtained film is then typically glue laminated to or coated with other materials to provide for e.g. the desired heat-sealability, or other desired properties.
  • US-A-4,927,677 describes composite materials for a retort container comprising a biaxially stretched film of a copolymer of vinlyidene chloride and an acrylic ester and a polypropylene film formed on one or both sides of the biaxially stretched film.
  • heat-stability has been considered as an essential feature for the materials to be used as lidstock in this type of applications.
  • Suitable bi-axially oriented heat-shrinkable films are those films which comprise at least a heat-sealable skin layer and are characterized by a maximum shrink force, at the temperature which is attained in the area of the lid-sealing station, not higher than 0.05 kg/cm in at least the transversal direction.
  • the temperature attained in the area of the lid sealing station causes a shrink of the sealed lid which keeps it tight on top of the tray.
  • thinner material provides improved optics and to reduced plastics waste.
  • a first object of the present invention is therefore in a packaging method which comprises:
  • the conventional lidding machines which are currently run with heat stable lidstocks can be used for this application, such as for instance the Ross Reiser, Caveco Automa, Caveco STL, Mecaplastic 2001, and Multivac T500 machines.
  • the lid web is cut after sealing and more preferably cutting occurs immediately after sealing while still in the lid sealing chamber.
  • some of the available tray lidding machines may require a mechanical modification.
  • a second object of the present invention is a package obtained by a method of the invention.
  • a package of the invention may comprise a product placed in a tray and a lid heat-sealed to the tray rims, optionally with a modified atmosphere between said lid and said tray, wherein the lid is made of a bi-axially oriented heat-shrinkable film which has been heated and stretched in transverse and longitudinal directions to align the macromolecule configuration; which shrinks by at least 5% in both transverse and longitudinal directions when exposed at the temperature of 110°C for 5s; and which is characterised in that at the temperature which is attained in the area of the lid-sealing station it has a maximum shrink force not higher than 0.05kg/cm in at least the transversal direction.
  • bi-axially oriented is used to define a polymeric material which has been heated and stretched in a longitudinal as well as in the transverse direction to align the macromolecule configuration.
  • heat-shrinkable film is intended to refer to a film that, when exposed at the temperature of 110°C for 5s, shrinks by at least 5% in both transverse and longitudinal directions.
  • the bi-axially oriented heat-shrinkable films to be used as tray liddings are not required to have a very high free shrink at the temperature which is attained in the area of the lid sealing station.
  • a free shrink of 5 to 10% in both directions would be more than sufficient to provide for the desired tight aspect of the lidding.
  • films with higher % free shrink are generally employed.
  • bi-axially oriented heat-shrinkable films are used in the improved process according to the present invention that have a free shrink, at the temperature which is attained in the area of the lid sealing station, of at least 10 %, preferably at least 15 %, and more preferably at least 20 %. More generally films with a % free shrink up to 60-70 at the temperature which is attained in the area of the lid sealing station can suitably be employed.
  • Bi-axially oriented heat-shrinkable films as described above can be obtained for instance by the trapped bubble process developed by Cryovac® in the early sixties.
  • the polymer(s) or polymer blend(s) of the film layer or layers are extruded or co-extruded through a round die to give a primary tube. This is rapidly quenched, for instance by means of a water bath, then heated to a suitably selected temperature by hot water or air, and oriented in the transverse direction by internal air pressure, and in the longitudinal direction by a differential speed of the pinch-rolls which hold the trapped bubble.
  • a tube is thus obtained of a film which has a reduced thickness with respect to the primary tube, whereas the ratio between the diameter of this tube and that of the primary tube is called transverse racking (or orientation) ratio and the ratio between the speed of the pinch rolls which stretch the bubble with respect to that of the pinch rolls which keep the primary tube gives the longitudinal racking ratio.
  • bi-axially oriented heat-shrinkable multilayer films may also be obtained by extrusion coating wherein a primary tube of one or more layers is coated with the other layers which are either sequentially extruded or coextruded thereon in a single step and then oriented as indicated above.
  • the films may also be subjected to cross-linking treatments, generally by submitting them to energetic radiation treatments, typically by high energy electron treatment.
  • irradiation is most preferably, but not necessarily, performed prior to orientation.
  • suitable radiation dosages of high energy which are referred to herein in terms of the radiation units "Grays", with one thousand Grays being designated as “KGrays”, may be in the range of up to 120 KGrays, more preferably from about 10 to about 90 KGrays.
  • the irradiation step may be carried out on the first tube obtained in the two-step extrusion process, before the extrusion coating thereof.
  • An alternative method for the manufacture of bi-axially oriented heat-shrinkable films as defined herein is by extrusion or co-extrusion through a flat die over a chill roll (optionally followed by an extrusion- or co-extrusion-coating step) and stretching of the thus obtained thick sheet in the transverse and longitudinal directions by the so-called tenterframe technique. Stretching in the longitudinal direction is usually achieved by passing the sheet, heated at the suitably selected orientation temperature, through pairs of rolls which rotate at different speeds, while stretching in the transverse direction is performed in a tenterframe oven heated to the suitably selected orientation temperature which comprises suitable stretching means. Said stretching steps can be carried out sequentially or simultaneously.
  • the tenterframe technique is actually used industrially for the manufacture of heat-set structures by carrying out, after the orientation step, a heat treatment - called heat-setting - wherein the films, while restrained against shrinkage, are heated at a temperature above the glass transition temperature of the polymers and below their melting points to stabilize the molecules in the oriented state and eliminate completely the shrinkage.
  • the stretching ratios in this case can be selected into a wider range as they may be up to 11 1, or even 12:1.
  • the percent free shrink i.e. the irreversible and rapid reduction, as a percent, of the original dimensions of a sample subjected to a given temperature under conditions where nil restraint to inhibit shrinkage is present, has been measured according to ASTM method D 2732, by immersing for 5s specimens of the structures (100 mm x 100 mm) in a water or oil bath set at the temperature at which the shrink properties of the structure were to be evaluated, by means of a free shrink holder. The specimens were then removed from the bath, quickly immersed into a water bath at room temperature to cool them down and the linear dimensions of the specimens in both the longitudinal and transverse directions were recorded.
  • L o is the initial length of side and Lf is the length of side after shrinking.
  • suitable films are those heat-shrinkable films that, when tested according to the ASTM method D-2732 at the temperature which is attained by the air or the modified atmosphere in the lid sealing station, show a free shrink of at least 5 % in both directions.
  • Preferred heat-shrinkable films are however those showing a free shrink of at least 10 %, preferably at least 15 %, and more preferably at least 20 % in both directions.
  • suitable heat-shrinkable films need to be characterized by a low shrink force.
  • shrink tension The shrink force which is the force released by the material during the shrinking process, when referred to the structure cross-section is termed shrink tension.
  • Specimens of the structure to be tested (2.54 cm x 14.0 cm) were cut in the longitudinal and transverse directions and clamped between two jaws, one of which was connected to a load cell. The two jaws kept the specimen in the center of a channel into which an impeller blew heated air and three thermocouples measured the temperature.
  • thermocouples The signal supplied by the thermocouples was amplified and sent to an output connected to the "X" axis of an X/Y recorder.
  • the signal supplied by the load cell was amplified and sent to an output connected to the "Y" axis of the X/Y recorder.
  • the impeller started blowing hot air and the force released by the sample was recorded in grams.
  • the temperature was increased up to a preselected maximum at a rate of 2°C/s. As the temperature increased the pen drew on the X/Y recorder the measured profile of the shrink force versus the temperature.
  • the instrument produced a curve of shrink force (g) versus temperature (°C); dividing the values thus recorded and multiplied by 10 -3 , by the specimen width (cm) the shrink force (in kg/cm) was obtained. By further dividing the shrink force by the specimen thickness (in cm), the shrink tension in kg/cm 2 was obtained at each given temperature.
  • the heat-shrinkable films to be used in the packaging method of the present invention should have, at the temperature which is attained by the air or the modified atmosphere in the lid sealing station, a shrink force not higher than 0.05 kg/cm at least in the transversal direction.
  • polymer(s) and polymer blend(s) which can be employed in order to get heat-shrinkable films to be used in the packaging method according to the present invention may vary widely as known in this field in order to provide the film with the desired mechanical, optical, and gas-permeability properties.
  • the desired shrink force characteristics of the heat-shrinkable films to be used as tray liddings in the process of the present invention might be obtained by suitably setting the key parameters in the manufacturing process (using low racking ratios, and/or high orientation temperatures), suitably selecting the polymers to be used and/or their sequence in the case of multilayer structures, reducing the shrink force of the available films by submitting them to a heat treatment under specific conditions, or by a combination of all these measures. Since, as indicated above, the shrink force also depends on the thickness of the structure, it may be possible to obtain a suitable structure having the shrink force characteristics below the above limits by reducing the thickness of otherwise unsuitable thicker structures.
  • the minimum thickness which can be used in the packaging method according to the present invention will depend on other characteristics required by the package in the specific application, such as mechanical resistance, gas-permeability, if a gas barrier package is desired, the need for tie layers to improve the bond, etc. and will depend on the particular mono- or multi-layer structure employed.
  • films as thin as 10 ⁇ can be employed, whereas balancing the several properties, heat-shrinkable films of an average thickness of from about 14 to about 40 ⁇ , e.g. 15 ⁇ , 19 ⁇ , 25 ⁇ , 30 ⁇ , or 35 ⁇ , are preferred.
  • Structures which may be employed in the packaging method and package according to the present invention are for instance those described in US-A-4,551,380, US-A-4,532,189, EP-A-388,177, EP-A-457,598, GB-A-2,221,649, WO-91/17886 and EP-A-206,826 or, when a gas barrier layer is desired, in EP-A-217,596, EP-A-251,769, EP-A-87,080, EP-A-141,555, and PCT patent application no. PCT/US95/16202 filed on December 15, 1995.
  • thermoformed tray When a thermoformed tray is employed this will typically be made of a mono- or multilayer thermoplastic material which may be gas permeable or a gas barrier material and comprises a heat-sealable inner skin layer (6) or heat-sealable strips on at least the tray rims (7).
  • gas permeable materials which can be used for the manufacture of thermoformed trays are e.g. multilayer laminates comprising a PVC layer and a polyethylene inner skin layer to provide the required heat-sealability, or in more general terms laminates comprising a PVC layer and an inner and optionally outer coating layer of any heat-sealable material which can heat-seal with the selected lid material.
  • thermoformed gas permeable trays can be obtained by thermoforming polystyrene sheet, either foamed or unfoamed, having a surface layer of a heat-sealable thermoplastic and an intermediate bonding layer.
  • a gas barrier thermoformed tray When a gas barrier thermoformed tray is desired this will typically be made of a multilayer structure comprising a gas barrier layer, such as for instance a layer comprising PVDC, EVOH, a poly- or copolyamide, etc. as known in this field, and at least the inner skin layer of a heat-sealable material. Other layers may clearly be present in order to provide the structure with the thickness and the mechanical properties required.
  • a gas barrier layer such as for instance a layer comprising PVDC, EVOH, a poly- or copolyamide, etc. as known in this field
  • Other layers may clearly be present in order to provide the structure with the thickness and the mechanical properties required.
  • barrier thermoformable structures are described for instance in US-A-4,735,855.
  • said gas barrier trays will be made by thermoforming a sheet of a surface layer of a heat-selable thermoplastic, an internal layer of a gas-barrier or low oxygen transmission material, as seen above, a bonding layer and a layer of thermoformable plastic, typically polystyrene, either unfoamed or foamed (indicated as EPS).
  • thermoformable plastic typically polystyrene, either unfoamed or foamed (indicated as EPS).
  • thermoformed trays can be made in-line or off-line.
  • pre-formed trays injection moulded trays can suitably be employed.
  • the preferred material in that case is still polystyrene, foamed or unfoamed, coated with a liner of a heat-sealable flexible film at least on the tray rims.
  • the coating of the injection moulded polystyrene tray will comprise a gas-barrier intermediate layer and will cover the whole tray surface.
  • Suitable dimensions of the trays will depend on the dimensions of the products to be packaged. Also the shape of the trays may vary in order to provide the packaged items with a better or more characterising appearance.
  • the dimensions of the tray rims is also not critical provided a sealing area of at least 2 mm, and preferably 3 mm is allowed to get a reliable seal.
  • a bi-axially oriented heat-shrinkable film characterized by a maximum shrink force, at the temperature which is attained in the area of the lid-sealing station, not higher than 0.04 kg/cm in at least the transversal direction will preferably be employed in the process according to the present invention.
  • a bi-axially oriented heat-shrinkable film characterized by a maximum shrink force, at the temperature which is attained in the area of the lid-sealing station, not higher than 0.03 kg/cm in at least the transversal direction might be even more preferably employed in the process according to the present invention.
  • thermoformed barrier trays about 225 mm in length, 170 mm in width, and 30 mm in depth (VITEMBAL) comprising an EPS substrate with an ethylene-vinyl alcohol copolymer as the barrier layer and a polyethylene heat-sealing layer (overall thickness of about 4 mm), are used on a MECAPLASTIC machine (MECA 2001).
  • MECAPLASTIC machine MECA 2001
  • the trays are put on the infeed conveyor and filled with the products to be packaged.
  • the machine is a 2-lane one, able to seal 4 trays per cycle and running at a speed of 8 cycles per minute.
  • the trays are then carried into the lid sealing station.
  • the heat-shrinkable film A (whose structure and characteristics are reported below) proceeds from an upward tensioned unwind unit along a fed path within this lid sealing station over the four packages that are positioned width-wise.
  • the sealing mould is closed and vacuum is pulled up to the value set on the machine panel, then the suitable gas mixture is injected and the heated platen with the protruding knives descends to cut the heat-shrinkable lidstock about 3 mm far from the tray contours and hermetically heat seal the lidstock to the flat top lips of the trays.
  • the sealing temperature is set on the machine panel to a value of around 120°C.
  • the separated trays then exit the lid sealing station along the two lanes while the next carrier of four trays is then accomodated into the lid sealing station. Downstream packaging steps are carried out as known in the art.
  • Film A used in this packaging method is a five-ply cross-linked film of structure A/B/C/B/A wherein A is a blend of 25 % ethylene-vinyl acetate copolymer, 25% linear medium density polyethylene, and 50% linear low density polyethylene containing slip, antiblock, and antifog agents, C is a blend of ethylene-vinyl alcohol copolymer and a polyamide, and B is a tie layer comprising a modified linear low density polyethylene.
  • the film is prepared by following substantially the same procedure described in Example 1 of EP-B-217,596.
  • the film thus obtained is then submitted to a heat treatment by passing the tubular flattened film through a processing unit consisting of 6 stainless steel rollers heated to a temperature of from about 70°C to about 90°C and two rollers cooled to about room temperature, at a constant speed, for a total heating time of about 1.60 s.
  • the thus obtained film which has an overall thickness of 25 ⁇ , has a maximum transversal shrink force of 0.043 kg/cm.
  • the % free shrink at the sealing temperature is about 50 % in both directions.
  • the obtained barrier package has a tray lidding only 25 ⁇ thick (while the conventional laminate lidding are much thicker), the lid is perfectly tight on top of the tray with a very good control of possible ballooning effects, it is bright with very good optics (better than those obtainable with the conventional laminates also because of the reduced thickness), there is no distortion of the tray, and there are no floppy borders around the sealing area.
  • Analogous results can be obtained by using a Caveco Automa machine with Coopbox trays or a Caveco STL machine with injection moulded barrier polystyrene foam trays.
  • Injection moulded barrier trays about 190 mm in length, 130 mm in width, and 35 mm in depth comprising an EPS substrate with a liner of ethylene-vinyl alcohol copolymer as the barrier layer and a polyethylene heat-sealing layer (overall thickness about 7 mm), are used on a MECAPLASTIC machine (MECA 2001) suitably modified so as to provide for the cutting of the lidding film immediately after sealing.
  • MECAPLASTIC machine MECA 2001
  • the trays are put on the infeed conveyor and filled with the products to be packaged.
  • the machine is a 3-lane one, able to seal 3 trays per cycle and running at a speed of 10 cycles per minute.
  • the trays are then carried into the lid sealing station.
  • Film A is used and the process is run as in Example 1 with the only difference that first the heated platen descends to heat seal the lidstock to the flat top lips of the trays and immediately after a series of knives provides for the cutting of the heat-shrinkable lidstock about 3 mm far from the tray contours.

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  • Mechanical Engineering (AREA)
  • Packages (AREA)
  • Closing Of Containers (AREA)

Claims (12)

  1. Verpackungsverfahren, bei dem
    (a) ein Tablett mit heißsiegelbaren Rändern bereitgestellt wird,
    (b) dieses Tablett mit dem zu verpackenden Produkt beladen wird,
    (c) der Deckel auf die Oberseite des Tabletts aufgebracht wird, wobei die sich berührenden Oberflächen der Tablettränder und des Deckels aus Materialien sind, die heiß miteinander verbunden werden können, um das Siegeln der Verpackung zu bewirken, wobei dieser Schritt die Verwendung einer biaxial orientierten heißschrumpffähigen Folie, die erhitzt und in Quer- und Längsrichtungen gestreckt worden ist, um die makromolekulare Konfiguration auszurichten, und die um mindestens 5% sowohl in Quer- als auch in Längsrichtung schrumpft, wenn sie 5 Sekunden einer Temperatur von 110°C ausgesetzt wird, als Deckel umfasst und
    (d) der Deckel auf die Tablettränder, gegebenenfalls mit einer modifizierten Atmosphäre zwischen Deckel und Tablett, heißgesiegelt wird, wobei die biaxial orientierte heißschrumpffähige Folie bei der Temperatur, die im Bereich der Deckelversiegelstation erreicht wird, eine maximale Schrumpfkraft von nicht größer als 0,05 kg/cm in mindestens der Querrichtung hat.
  2. Verfahren nach Anspruch 1, bei dem die biaxial orientierte heißschrumpffähige Folie bei der Temperatur, die in dem Bereich der Deckelsiegelstation erreicht wird, durch eine maximale Schrumpfkraft nicht größer als 0,04 kg/cm gekennzeichnet ist.
  3. Verfahren nach Anspruch 2, bei dem die biaxial orientierte heißschrumpffähige Folie bei der Temperatur, die in dem Bereich der Deckelsiegelstation erreicht wird, durch eine maximale Schrumpfkraft nicht größer als 0,03 kg/cm gekennzeichnet ist.
  4. Verfahren nach Anspruch 1, bei dem das Tablett thermogeformt oder spritzgegossen ist.
  5. Verfahren nach einem der vorherigen Ansprüche 1 bis 4, bei dem die biaxial orientierte heißschrumpffähige Folie eine Dicke von etwa 14 bis etwa 40µ hat.
  6. Verfahren nach einem der vorherigen Ansprüche 1 bis 5, bei dem die biaxial orientierte heißschrumpffähige Folie bei der Temperatur, die in dem Bereich der Deckelsiegelstation erreicht wird, einen freien Schrumpf von mindestens 10%, bevorzugt mindestens 15% und besonders bevorzugt von mindestens 20% in beide Richtungen hat.
  7. Eine Verpackung, die nach dem Verfahren gemäß Anspruch 1 erhalten wurde.
  8. Verpackung, die ein auf einem Tablett plaziertes Produkt und einen an die Tablettränder heißgesiegelten Deckel, gegebenenfalls mit einer modifizierten Atmosphäre zwischen dem Deckel und dem Tablett, umfasst, bei der der Deckel aus einer biaxial orientierten heißschrumpffähigen Folie hergestellt ist, die erhitzt und in Quer- und Längsrichtung gestreckt worden ist, um die makromolekulare Konfiguration auszurichten, die, wenn sie 5 Sekunden einer Temperatur von 110°C ausgesetzt wird, um mindestens 5% sowohl in Quer- als auch in Längsrichtung schrumpft und die bei der Temperatur, die im Bereich der Deckelsiegelstation erreicht wird, durch eine maximale Schrumpfkraft nicht größer als 0,05 kg/cm in mindestens der Querrichtung gekennzeichnet ist.
  9. Verpackung nach Anspruch 8, bei der die biaxial orientierte heißschrumpffähige Folie bei der Temperatur, die in dem Bereich der Deckelsiegelstation erreicht wird, durch eine maximale Schrumpfkraft in mindestens der Querrichtung von nicht größer als 0,04 kg/cm gekennzeichnet ist.
  10. Verpackung nach Anspruch 9, bei der die biaxial orientierte heißschrumpffähige Folie bei der Temperatur, die in dem Bereich der Deckelsiegelstation erreicht wird, durch eine maximale Schrumpfkraft in mindestens der Querrichtung von nicht größer als 0,03 kg/cm gekennzeichnet wird.
  11. Verpackung nach einem der vorhergehenden Ansprüche 8 bis 10, bei der die biaxial orientierte heißschrumpffähige Folie bei der Temperatur, die im Bereich der Deckelsiegelstation erreicht wird, einen freien Schrumpf von mindestens 10%, bevorzugt mindestens 15% und besonders bevorzugt mindestens 20% in beiden Richtungen hat.
  12. Verpackung nach einem der vorhergehenden Ansprüche 8 bis 11, bei der die biaxial orientierte heißschrumpffähige Folie eine Dicke von etwa 14 bis etwa 40µ hat.
EP19960102512 1995-03-01 1996-03-01 Verpackungs-Verfahren Expired - Lifetime EP0729900B1 (de)

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Application Number Priority Date Filing Date Title
EP95102885 1995-03-01
EP95102885 1995-03-01
EP19960102512 EP0729900B1 (de) 1995-03-01 1996-03-01 Verpackungs-Verfahren

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EP0729900A2 EP0729900A2 (de) 1996-09-04
EP0729900A3 EP0729900A3 (de) 1998-01-28
EP0729900B1 true EP0729900B1 (de) 2003-07-23

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ZA200102038B (en) * 1998-09-15 2002-03-12 Steen Pedersen Packing tray and method for its production and use.
NZ560746A (en) 2005-02-18 2011-03-31 Cryovac Inc Packaging process for fresh meat products, new fresh meat package obtainable thereby and twin lidding film suitable therefor
EP2805821B3 (de) 2013-05-21 2017-03-01 Cryovac, Inc. Wärmeschrumpffolie mit Gassperre
CN109195790B (zh) 2016-06-01 2021-07-23 克里奥瓦克公司 阻气可热收缩膜
AU2022201577B2 (en) 2021-03-09 2023-11-02 Flexopack S.A. Multilayer monoaxially oriented film

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JPS61295036A (ja) * 1985-06-25 1986-12-25 呉羽化学工業株式会社 熱収縮性積層フイルム
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EP0729900A2 (de) 1996-09-04
EP0729900A3 (de) 1998-01-28

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