Food receptacle for microwave cooking

• US 4,641,005 A
• Filed: 01/21/1986
• Issued: 02/03/1987
• Est. Priority Date: 03/16/1979
• Status: Expired due to Term

• Current Assignee: Graphic Packaging International Incorporated
• Original Assignee: James River Corporation (KOCH Industries Incorporated)
• Inventors: Seiferth, Oscar E.
• Primary Examiner(s): Leung, Philip H.
• Application Number:
  US06/820,593
• Time in Patent Office: 378 Days
• Field of Search: 219/10.55 E, 219/10.55 M, 219/10.55 F, 99/451, 99/DIG., 14, 229/3.5 MF, 426/107, 426/113, 426/124, 426/234, 426/237, 426/241, 426/243, 426/392, 426/396, 426/412, 126/390, 156/233, 428/425.8, 428/457, 428/458, 427/250, 427/404
• US Class Current: 219/730
• CPC Class Codes: A47J 36/022 Cooking- or baking-vessels or supports thereof for using only once eating- or serving-plates for using only once A47G19/02
• CPC Class Codes: B65D 2581/3466 Microwave reactive material applied by vacuum, sputter or vapor deposition
• CPC Class Codes: B65D 2581/3472 Aluminium or compounds thereof
• CPC Class Codes: B65D 2581/3479 Other metallic compounds, e.g. silver, gold, copper, nickel
• CPC Class Codes: B65D 2581/3494 Microwave susceptor B65D2581/3487 takes precedence
• CPC Class Codes: B65D 81/34 for packaging foodstuffs or other articles intended to be cooked or heated within the package
• CPC Class Codes: B65D 81/3446 specially adapted to be heated by microwaves
• CPC Class Codes: Y10S 99/14 Induction heating
• CPC Class Codes: Y10T 428/31605 Next to free metal

Abstract

A disposable food receptacle for use in microwave cooking is disclosed which includes a provision to brown the exterior of the food in the receptacle. A thin layer of an electrically conductive material, such as an elemental metal is incorporated into the receptacle on the food contacting surfaces thereof, so that the conductive layer will become heated by the microwave radiation and will, in turn, brown the exterior of the food in the receptacle. The conductive layer is formed as an extremely thin film deposited on a substrate protective layer by a process of a vacuum vapor deposition.

Claims

1. A laminate for use in a disposable container adapted to heat the surface of a quantity of food when exposed to microwave energy, said laminate comprising

(a) a continuous microwave interactive layer of elemental metal having a thickness which is sufficiently small to cause said microwave interactive layer, when subjected to microwave energy, to heat up to a temperature which is sufficient to heat the surface of food in heat transfer relationship therewith,

(b) protective means for said microwave interactive layer, said protective means including a smooth surfaced plastic film having sufficient stability at high temperature that it will not degrade when the laminate is subjected to sufficient microwave energy to heat the surface of the quantity of food, and

(c) support means for providing structural support for said interactive layer and said plastic film, said support means being formed of paper stock material having sufficient structural stability at the high temperature necessary for heating the surface of the quantity of food to maintain its physical shape;

wherein said laminate is formed by the process including the successive steps of vacuum depositing said microwave interactive layer onto a smooth surface of said plastic film followed by the step of bonding directly said plastic film upon which said microwave interactive layer has been vacuum deposited to one side of said paper stock material in a manner to cause said plastic film and said microwave interactive layer to be held in bonded relationship with said support means to cause the surface of a quantity of food, when in heat transfer relationship therewith, to be heated when the laminate is subjected to microwave energy.

2. A laminate according to claim 1, wherein the step of bonding said plastic film to said paper stock material includes the step of bonding directly to said paper stock material the side of said plastic film upon which said interactive layer has been vapor deposited.

3. A laminate according to claim 1, wherein said plastic film is adapted to directly contact the surface of the quantity of food.

4. A laminate according to claim 1, wherein said microwave interactive layer has a thickness of less than about 700 angstroms.

5. A laminate according to claim 1, wherein said microwave interactive layer has a resistivity of greater than about 0.4 ohms per square.

6. A laminate according to claim 1, wherein said laminate includes a tray member of predetermined physical shape.

7. A laminate according to claim 1, wherein said step of vacuum depositing includes the step of vacuum vapor depositing said metal onto said plastic film.

8. A laminate according to claim 1, wherein said paper stock material is formed of a material constituting a greater barrier to heat transfer than said plastic film.