EP0487166A1 - Suscepteur multicouches pour températures basses - Google Patents

Suscepteur multicouches pour températures basses Download PDF

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Publication number
EP0487166A1
EP0487166A1 EP91203039A EP91203039A EP0487166A1 EP 0487166 A1 EP0487166 A1 EP 0487166A1 EP 91203039 A EP91203039 A EP 91203039A EP 91203039 A EP91203039 A EP 91203039A EP 0487166 A1 EP0487166 A1 EP 0487166A1
Authority
EP
European Patent Office
Prior art keywords
layer
substrate layer
melting point
substructure
adhered
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91203039A
Other languages
German (de)
English (en)
Inventor
Peter Gatenby Turner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Greif International Holding BV
Original Assignee
Koninklijke Emballage Industrie Van Leer BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Emballage Industrie Van Leer BV filed Critical Koninklijke Emballage Industrie Van Leer BV
Publication of EP0487166A1 publication Critical patent/EP0487166A1/fr
Withdrawn legal-status Critical Current

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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
    • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D81/34—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package
    • B65D81/3446—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package specially adapted to be heated by microwaves
    • 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
    • B65D2581/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3463—Means for applying microwave reactive material to the package
    • B65D2581/3466—Microwave reactive material applied by vacuum, sputter or vapor deposition
    • 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
    • B65D2581/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3471—Microwave reactive substances present in the packaging material
    • B65D2581/3472—Aluminium or compounds thereof
    • 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
    • B65D2581/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3471—Microwave reactive substances present in the packaging material
    • B65D2581/3477—Iron or compounds thereof
    • B65D2581/3478—Stainless steel
    • 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
    • B65D2581/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D2581/34—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within
    • B65D2581/3437—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within specially adapted to be heated by microwaves
    • B65D2581/3486—Dielectric characteristics of microwave reactive packaging
    • B65D2581/3487—Reflection, Absorption and Transmission [RAT] properties of the microwave reactive package

Definitions

  • the invention relates to a layered susceptor material comprising an active microwave absorbing substructure consisting of
  • a similar susceptor, but described as having a far lower electrical sheet resistance of the metal layer, is for instance the subject of US patent 4.641.005.
  • a susceptor can be defined as a material which absorbs microwave energy in order to rapidly heat up and provide a hot surface to aid cooking.
  • a polyester film e.g. a polyethylene therephtalate film
  • substrate layer which film after being metallised is adhered to a paper or paper-board layer functioning as said stock material layer.
  • Susceptors of this type are generally accepted as browning aids for a wide range of microwaveable food products. These susceptors are for instance used as active packaging to generate surface crisping and browning of many pastry products, which would otherwise not be successfully reheatable in the microwave oven.
  • Another major area of use has been in pop-corn bags of the self-inflating type described for instance in US patent 4.571.337 where a susceptor increases the popping efficiency and reduces cooking time.
  • susceptors have risen on two fronts, both inter-related. Where the susceptor surface is not in intimate contact with a food product to provide an effective heat sink for the heat generated by the susceptor, then the susceptor can self-heat to temperatures well in excess of 200°C. These high temperatures to which the packaging materials and components are not normally screened, can cause release of volatiles from the polyester film surface, and degradation products from the polyester film surface, in close proximity to the food.
  • the paper or paperboard substrate can also brown and char, emitting undesirable (possibly harmful) fumes and smells.
  • the food product originally isolated from direct exposure to the laminating adhesive and paper base, becomes exposed at the cracks to the hot adhesive and paper, and to any volatiles emitted by these hot (>200°C) surfaces.
  • the temperature limit of conventional susceptors is determined by the melting point of the polyester film, namely 265°C. Above this temperature, it no longer provides a solid base for the microwave absorbing metal layer. The thermal stresses cause the metal layer to become discontinuous and a much weaker microwave absorber. (Without this automatic self cut-off property, temperatures would rise even further till the susceptor ignited).
  • the objectives of the invention are two-fold: to construct a susceptor with similar heating abilities to existing products, but having a maximum temperature peak lower than the 200+ degrees Celsius of current products; and to construct a susceptor which retains an unbroken barrier surface in contact with the food during heating and use.
  • the layered susceptor material described in the first paragraph is according to the invention characterized in that said inert plastic film substrate layer is made of a plastic material with a melting point below 200°C and further that the substrate layer material is in an oriented state.
  • the layered susceptor material comprises a further layer of a material with a melting point above the melting point of said substrate layer adhered to said active microwave absorbing substructure opposite the surface to which the stock material is adhered.
  • Said further layer functions as cover layer which, because of the higher melting point temperature will be stable under all circumstances and, during use of the susceptor, isolates the food product from the layers of said substructure.
  • Figure 1 illustrates a cross-sectional view through a layered susceptor material according to the invention.
  • Figure 2 illustrates a cross-sectional view through a preferred embodiment of a layered susceptor material according to the invention.
  • Figure 3 illustrates another embodiment of the layered susceptor material according to the invention.
  • Figure 1 illustrates a cross-sectional view through a layered susceptor material comprising a substrate layer 10 and a metal layer 12 which is deposited on the substrate layer 10.
  • the substrate layer is a thin inert plasic film which forms the material to be vacuum coated with the metal layer 12. Said two layers form together a substructure which can be manufactured as separate product.
  • a stock material layer 16 is adhered to said substructure by a layer of adhesive 14. In the illustrated embodiment, the stock layer is adhered to the metal layer 12.
  • the substrate layer 10 is made of a plastic material having a melting point below 200°C and is preferably made of biaxially oriented polypropylene film of a grade suitable for food packaging applications and suitable for metallising.
  • melting point not only represents the temperature at which a polymer changes from solid phase to liquid phase, but also indicates the softening point or temperature range at which non crystalline plastics change from solid state to viscous state.
  • the substrate layer is a biaxially oriented film made of polypropylene.
  • the thickness of the film 10 is preferably between 5 and 50 ⁇ .
  • the metal layer 12 can be any metal or alloy which is stable and corrosion resistant as a thin film, but is preferably aluminium or stainless steel, which are metals already widely accepted in food packaging and food preparation.
  • the metal layer is applied to the substrate layer by means of a suitable vacuum deposition process such as thermal evaporation or sputtering.
  • a suitable vacuum deposition process such as thermal evaporation or sputtering.
  • the substrate film is transported, at a controllable speed, over the vapour source allowing the vapour condense on the substrate to build up the desired thickness of fractions of one micron.
  • the final metal coating has preferably a sheet resistance in the range of 50 to 500 ohms per square.
  • the optical density for an aluminium metallised film should preferably be in the range of 0,18 to 0,28 such that the metal layer has a microwave absorbency of between 10% and 50%.
  • the correct thickness can be achieved by those skilled in the art by controlling the metal evaporation or sputtering rate and by control of the film speed over the metal vapour source.
  • the stock material layer 16 consists of paper or paperboard.
  • the metallised film is laminated to this paper or paperboard using an adhesive approved for food packaging use, whereby the metallised surface of the substrate film is in contact with the adhesive 14.
  • FIG. 2 A cross-sectional view through a further developed embodiment of a layered susceptor material according to the invention is illustrated in figure 2. Those layers, which are also present in the embodiment illustrated in figure 1, are indicated by the same reference numbers.
  • the difference between figure 1 and figure 2 is the fact that a further plastic film 18 is adhered by means of an adhesive layer 20 to the top of the metallised substrate film 10.
  • the further plastic layer has a melting point temperature above the melting point temperature of the (polypropylene) substrate film and consists preferably of polyester.
  • the purpose of this further layer is to provide a protective barrier between the actual food product and the microwave absorbing substructure.
  • the substructure comprising the layers 10, 12 has a self cut-off property at temperatures of about 170°, determined by the melting point of the polypropylene film, there is no danger that the polyester film 18 will start releasing volatiles or degradation products because of overheating of said layer. On the other hand any volatiles or degradation products which might be released by the polypropylene film 10 are effectively blocked from the food product by the further layer of polyester.
  • Figure 3 illustrates a cross-sectional view through another embodiment of the susceptor material according to the invention which only differs from the embodiment illustrated in figure 2 by the orientation of the substructure comprising the polypropylene film 10 and the metallised layer 12.
  • the paper or paperboard stock material layer 16 is in this embodiment not adhered to the metal layer 12 but adhered to the polypropylene layer 10.
  • the further plastic layer 18 consisting of polyester is adhered by means of the adhesive layer 20 to the metal layer 12.
  • this embodiment has the self cut-off property at a rather low temperature determined by the melting point of the polypropylene film (170°C).
  • a roll of cast, i.e. unoriented, polypropylene film (Karl Dickel "Safran” PP 350 MET) was metallised by vacuum evaporation of aluminium to produce a coating having an optical density of 0.2.
  • the metallised film was laminated, using a water-based adhesive (Duraflex 56) applied to a dry coating weight of 3 g/m2 to the metallised side, to a 240 g/m2 paperboard.
  • Pieces of this laminated board, cut to 11x18 cm (approx. 200 cm2) were tested as susceptor for browning pieces of fresh pizza dough weighing 190 g.
  • Two pieces of dough were each placed on a 200 cm2 susceptor board in a 600 W microwave oven, and cooked at full, i.e. continuous, power for 5 minutes. As intended and expected, rapid heating of the board occurred, but surprisingly, heating continued unregulated well beyond the melting point of polypopylene. Burning of the board in "hot spots" occurred. The oven filled with smoke from the burnt board, polypropylene, and pastry.
  • a roll of biaxially oriented polypropylene film (ICI "Propafilm” MVG) was metallised in the same way as example 1 to an optical density of 0.2, and subsequently laminated to the same board and with the same adhesive as in example 1.
  • the susceptor board was tested in a microwave oven with pizza dough as in example 1.
  • the pizza dough was observed to be lightly browned on the undersurface in contact with the board. Examination of the surface of the used susceptor revealed a dulling of the surface. When examined under a scanning electron microscope, the surface was seen to have changed from the glossy smooth surface of the original film to a textured surface of a melted and re-solidified polymer. The surface was continuous apart from small "vent holes" a few microns in diameter with occasional larger holes up to 100 ⁇ (0.1 mm) across.
  • Rectangles of this board were again tested in the 600 W microwave oven with 190 g pieces of pizza dough. After 5 minutes cooking, the pizza dough had developed browning on its undersurface, the board itself remained unburnt, and the polyester film in contact with the food remained continuous, unbroken, and showed no evidence of melting.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Laminated Bodies (AREA)
  • Constitution Of High-Frequency Heating (AREA)
  • Cookers (AREA)
  • Electric Ovens (AREA)
EP91203039A 1990-11-21 1991-11-20 Suscepteur multicouches pour températures basses Withdrawn EP0487166A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL9002540 1990-11-21
NL9002540A NL9002540A (nl) 1990-11-21 1990-11-21 Lage temperatuur susceptor.

Publications (1)

Publication Number Publication Date
EP0487166A1 true EP0487166A1 (fr) 1992-05-27

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ID=19858012

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91203039A Withdrawn EP0487166A1 (fr) 1990-11-21 1991-11-20 Suscepteur multicouches pour températures basses

Country Status (3)

Country Link
EP (1) EP0487166A1 (fr)
JP (1) JPH0529076A (fr)
NL (1) NL9002540A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0559447A1 (fr) * 1992-03-04 1993-09-08 Westvaco Corporation Suscepteur imprimé pour four à microondes ayant une barrière thermique
US6960748B2 (en) 2003-10-09 2005-11-01 Smurfit-Stone Container Enterprises, Inc. Collapsible microwave popcorn box
US7112771B2 (en) 2004-03-09 2006-09-26 Ball Corporation Microwavable metallic container
US7378625B2 (en) 2004-03-09 2008-05-27 Ball Corporation Microwavable metallic container
US8080770B2 (en) 2004-03-09 2011-12-20 Ball Corporation Microwavable metallic container
US10071182B2 (en) 2014-10-14 2018-09-11 Samuel E. Lynch Methods for treating wounds

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102662973B1 (ko) * 2023-05-08 2024-05-03 태영에스티 주식회사 궐련형 전자담배용 스틱
KR102662969B1 (ko) * 2023-05-08 2024-05-03 태영에스티 주식회사 궐련형 전자담배용 스틱

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0187512A2 (fr) * 1984-12-30 1986-07-16 Ajinomoto Co., Inc. Boîte en matériau plastique transparent
GB2211380A (en) * 1987-10-21 1989-06-28 Int Paper Co Flexible package for microwave cooking
EP0340037A2 (fr) * 1988-04-29 1989-11-02 E.I. Du Pont De Nemours And Company Matériaux laminés moulants pour l'emballage, sensibles à l'énergie des micro-ondes
EP0371739A2 (fr) * 1988-11-28 1990-06-06 Beckett Industries Inc. Article de chauffage et son procédé de chauffage

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0187512A2 (fr) * 1984-12-30 1986-07-16 Ajinomoto Co., Inc. Boîte en matériau plastique transparent
GB2211380A (en) * 1987-10-21 1989-06-28 Int Paper Co Flexible package for microwave cooking
EP0340037A2 (fr) * 1988-04-29 1989-11-02 E.I. Du Pont De Nemours And Company Matériaux laminés moulants pour l'emballage, sensibles à l'énergie des micro-ondes
EP0371739A2 (fr) * 1988-11-28 1990-06-06 Beckett Industries Inc. Article de chauffage et son procédé de chauffage

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0559447A1 (fr) * 1992-03-04 1993-09-08 Westvaco Corporation Suscepteur imprimé pour four à microondes ayant une barrière thermique
US6960748B2 (en) 2003-10-09 2005-11-01 Smurfit-Stone Container Enterprises, Inc. Collapsible microwave popcorn box
US7112771B2 (en) 2004-03-09 2006-09-26 Ball Corporation Microwavable metallic container
US7378625B2 (en) 2004-03-09 2008-05-27 Ball Corporation Microwavable metallic container
US7812292B2 (en) 2004-03-09 2010-10-12 Ball Corporation Microwavable metallic container
US8080770B2 (en) 2004-03-09 2011-12-20 Ball Corporation Microwavable metallic container
US10071182B2 (en) 2014-10-14 2018-09-11 Samuel E. Lynch Methods for treating wounds

Also Published As

Publication number Publication date
NL9002540A (nl) 1992-06-16
JPH0529076A (ja) 1993-02-05

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