Flexible disposable material for forming a food container for microwave cooking

• US 4,890,439 A
• Filed: 11/09/1988
• Issued: 01/02/1990
• Est. Priority Date: 11/09/1988
• Status: Expired due to Term

• Current Assignee: Graphic Packaging International Incorporated
• Original Assignee: James River Corporation (KOCH Industries Incorporated)
• Inventors: Smart, Allen A.
• Primary Examiner(s): Culver, Horace M.
• Application Number:
  US07/268,851
• Time in Patent Office: 419 Days
• Field of Search: 53/410, 53/411, 53/440, 53/449, 53/127, 53/128, 53/172, 53/562, 53/455, 53/456, 493/187, 493/264, 493/267, 493/189, 426/107, 426/113, 426/124, 426/234, 426/237, 219/10.55 E, 428/425.8, 428/457, 428/458, 428/548, 428/551, 428/615
• US Class Current: 53/410
• CPC Class Codes: B31B 2155/00 Flexible containers made from webs
• CPC Class Codes: B31B 2170/20 having multi-layered walls, e.g. laminated or lined
• CPC Class Codes: B31B 50/742 Coating; Impregnating; Waterproofing; Decoating
• CPC Class Codes: B65D 2581/3494 Microwave susceptor B65D2581/3487 takes precedence
• CPC Class Codes: B65D 81/3461 Flexible containers, e.g. bags, pouches, envelopes
• CPC Class Codes: Y10T 428/12493 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
• CPC Class Codes: Y10T 428/31605 Next to free metal
• CPC Class Codes: Y10T 428/31681 Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]

Abstract

A packaging material and a method of forming the packaging material into a flexible, disposable food container adapted to contain and maintain food in a fresh and sanitary condition, and to ship, display, heat and brown, and serve the food is disclosed. The method includes forming patches of microwave interactive material on a web of plastic and laminating the web of plastic to one side of a web of structural stock material to form a composite web; the microwave interactive material is sandwiched between the web of plastic and the web of structural stock material. Sealant is applied to portions of the plastic layer in registry with the patches of microwave interactive material to seal ends of the composite web. Printed graphics are applied to portions of the structural stock material layer in registry with the patches of microwave interactive material and the sealant. The formed container is sufficiently flexible to contain food having curved and irregular surfaces and to maximize contact of the food with the portion of the container housing the microwave interactive material. The container is sealed so that portions of the composite web extend as fins beyond the sealed ends of the food-containing portion of the container. The container also is capable of receiving food before the food is frozen to prevent portions or parts of the food from falling out of their proper place in the food packaging process.

Claims

1. A packaging material for forming a flexible, disposable food container adapted to contain and maintain food in a fresh and sanitary condition, to ship the food from a factory to a warehouse to a store to a home, to display the food to the consumer in the store in a presentable fashion, to heat and brown the food when exposed to microwave energy in a microwave oven, and to serve the food to the consumer after removal from the microwave oven, the packaging material comprising:

a first layer of material;

a layer of microwave interactive material formed as patches on the first layer of material;

a layer of structural stock material laminated to the first layer of material so as to sandwich the patches of microwave interactive material between the first layer of material and the layer of structural stock material; and

sealant disposed on portions of the first layer of material in registry with the patches of microwave interactive material, the sealant being located to seal ends of the packaging material to form the container and to prevent the heat of the microwave interactive material from disrupting the seal during cooking in the microwave oven.

2. A packaging material according to claim 1 wherein the first layer of material comprises paper.

3. A packaging material according to claim 1 wherein the first layer of material comprises plastic.

4. A packaging material according to claim 3 further comprising printed graphics applied to portions of the structural stock material layer in registry with the patches of microwave interactive material and the sealant to provide a visually appealing package by properly centering the graphics without impairing the effectiveness of the microwave interactive material, without applying the graphics in difficult-to-read portions of the package, and without using a repeated, random pattern.

5. A packaging material according to claim 3 wherein the packaging material is sufficiently flexible to form a container to contain food having curved and irregular surfaces and to maximize contact of the food with the portion of the container housing the microwave interactive material.

6. A packaging material according to claim 3 wherein the packaging material can form a container that is sealable so that portions of the packaging material extend as fins beyond the sealed ends of the food-containing portion of the container to enable the container to be opened without destroying the container, to allow the container to be used for cooking and to permit browning and venting while inhibiting steaming of the food, and wherein the fins are usable as handles for the opened container.

7. A packaging material according to claim 3 wherein the packaging material can form a container that is capable of receiving food before the food is frozen to prevent portions or parts of the food from falling out of their proper place in the food packaging process.

8. A packaging material according to claim 3 wherein the layer of plastic comprises polyester.

9. A packaging material according to claim 3 wherein the microwave interactive material comprises metal.

10. A packaging material according to claim 3 wherein the web of structural stock material comprises paper having low density, high insulating capacity, and high heat stability.

11. A packaging material according to claim 3 wherein the sealant comprises a hot melt material.

12. A packaging material according to claim 3 wherein the sealant comprises a cohesive, pressure sensitive cold seal.

39. A flexible, disposable food container adapted to contain and maintain food in a fresh and sanitary condition, to ship the food from a factory to a warehouse to a store to a home, to display the food to the consumer in the store in a presentable fashion, to heat and brown the food when exposed to microwave energy in a microwave oven, and to serve the food to the consumer after removal from the microwave oven, the flexible, disposable food container being formed by the method of claim 11.

13. A method of forming a flexible, disposable food container adapted to contain and maintain food in a fresh and sanitary condition, to ship the food from a factory to a warehouse to a store to a home, to display the food to the consumer in the store in a presentable fashion, to heat and brown the food when exposed to microwave energy in a microwave oven, and to serve the food to the consumer after removal from the microwave oven, the method of forming the flexible, disposable food container comprising the steps of:

forming patches of microwave interactive material on a web of material;

laminating the web of material to one side of a web of structural stock material to form a composite web having a material layer and a structural stock material layer so that the microwave interactive material is sandwiched between the web of material and the web of structural stock material;

applying sealant to portions of the material layer in registry with the patches of microwave interactive material to seal ends of the composite web to form the container and to prevent the heat of the microwave interactive material from disrupting the seal during cooking in the microwave oven; and

rewinding the composite web onto a roll preparatory to forming the composite web into a container and inserting food therein.

14. A method according to claim 13 wherein said web of material comprises plastic.

15. A method according to claim 14 further comprising printed graphics applied to portions of the structural stock material layer in registry with the patches of microwave interactive material and the sealant to provide a visually appealing package by properly centering the graphics without impairing the effectiveness of the microwave interactive material, without applying the graphics in difficult-to-read portions of the package, and without using a repeated, random pattern.

16. A method according to claim 14 further comprising the steps of:

forming the end of the composite web into a container shape and sealing appropriate ends of the container to maintain the container shape;

inserting food into the container;

sealing the container around the food; and

cutting the container off of the composite web.

17. A method according to claim 14 wherein the container is sufficiently flexible to contain food having curved and irregular surfaces and to maximize contact of the food with the portion of the container housing the microwave interactive material.

18. A method according to claim 14 wherein the container is sealed so that portions of the composite web extend as fins beyond the sealed ends of the foodcontaining portion of the container to enable the container to be opened without destroying the container, to allow the container to be used for cooking and to permit browning and venting while inhibiting steaming of the food, and wherein the fins are usable as handles for the opened container.

19. A method according to claim 16 wherein the container also is capable of receiving food before the food is frozen to prevent portions or parts of the food from falling out of their proper place in the food packaging process.

40. A flexible, disposable food container adapted to contain and maintain food in a fresh and sanitary condition, to ship the food from a factory to a warehouse to a store to a home, to display the food to the consumer in the store in a presentable fashion, to heat and brown the food when exposed to microwave energy in a microwave oven, and to serve the food to the consumer after removal from the microwave oven, the flexible, disposable food container being formed by the method of claim 17.

20. A method of forming a flexible, disposable food container adapted to contain and maintain food in a fresh and sanitary condition, to ship the food from a factory to a warehouse to a store to a home, to display the food to the consumer in the store in a presentable fashion, to heat and brown the food when exposed to microwave energy in a microwave oven and to serve the food to the consumer after removal from the microwave oven, the method of forming the flexible, disposable food container comprising the steps of:

forming patches of microwave interactive material on a web of plastic;

laminating the web of plastic to one side of a web of structural stock material to form a composite web having a plastic layer and a structural stock material layer so that the microwave interactive material is sandwiched between the web of plastic and the web of structural stock material;

applying sealant to portions of the plastic layer in registry with the patches of microwave interactive material to seal ends of the composite web to form the container and to prevent the heat of the microwave interactive material from disrupting the seal during cooking in the microwave oven;

applying printed graphics to portions of the structural stock material layer in registry with the patches of microwave interactive material and the sealant to provide a visually appealing package by properly centering the graphics without impairing the effectiveness of the microwave interactive material, without applying the graphics in difficult-to-read portions of the package, and without using a repeated, random pattern;

rewinding the composite web onto a roll preparatory to forming the composite web into a container;

forming the composite web into a container shape and sealing appropriate ends of the container to maintain the container shape;

inserting the food into the container;

sealing the container around the food; and

cutting off the container from the composite web;

wherein the container is sufficiently flexible to contain food having curved and irregular surfaces and to maximize contact of the food with the portion of the container housing the microwave interactive material;

wherein the container is sealed so that portions of the composite web extend as finds beyond the sealed ends of the food-containing portion of the container to enable the container to be opened without destroying the container, to allow the container to be used for cooking and to permit browning while inhibiting steaming of the food, and wherein the fins are usable as handles for the opened container; and

wherein the container is capable of receiving food before the food is frozen to prevent portions or parts of the food from falling out of their proper place in the food packaging process.

21. A method according to claim 20 wherein the web of plastic comprises polyester.

22. A method according to claim 20 wherein the patches of microwave interactive material are formed on the web of plastic by chemically focusing to eliminate the microwave interactive capability of portions of metal on a metallized plastic web so that patches of operational microwave interactive material remain in the required locations.

23. A method according to claim 20 wherein the step of forming patches of microwave interactive material on a web of plastic comprises mechanically removing portions of microwave interactive material from a metallized web of plastic so that patches of microwave interactive material remain in the required locations.

24. A method according to claim 20 wherein the step of forming patches of microwave interactive material on a web of plastic comprises printing a layer of microwave interactive material in the required locations of the web of plastic.

25. A method according to claim 20 wherein the step of forming patches of microwave interactive material on a web of plastic comprises applying patches of microwave interactive material on a web of plastic in the required locations.

26. A method according to claim 20 wherein the microwave interactive material comprises metal.

27. A method according to claim 20 wherein the web of structural stock material comprises paper having low density, high insulating capacity, and high heat stability.

28. A method according to claim 20 wherein the sealant comprises a hot melt material.

29. A method according to claim 20 wherein the sealant comprises a cohesive, pressure sensitive cold seal.

30. A method according to claim 20 further comprising the step of lacquering the web of structural stock material.

31. A method according to claim 22 wherein the chemical focusing is performed using sodium hydroxide and wherein the method further comprises the step of heating the web of plastic after the patches of microwave interactive material have been formed to promote the sodium hydroxide reaction.

32. A method according to claim 20 wherein the web of structural stock material and the web of plastic both have widths equal to a multiple of widths of the finished food container and wherein the method further comprises the step of cutting the composite web in a lengthwise direction to form a plurality of composite webs each having a width equal to the width of a food container.

33. A method according to claim 20 wherein the food is brought to the food container in a horizontal direction and the food container is sealed around the food using a cold seal.

34. A method according to claim 20 wherein the food is dropped vertically onto the package and the package is folded around the food using a hot melt seal.

35. A method according to claim 20 wherein a plurality of food articles are disposed in each container and wherein the food articles disposed in each container are arranged so that the food articles are only one level of food high within the container to maximize contact between the food articles and the microwave interactive layer.

36. A method according to claim 35 wherein the container provides a large area of microwave interactive material per unit of food per unit cost.

37. A method according to claim 20 wherein the forming patches and laminating steps are performed on a central impression drum so that registration of one step on the web of plastic places the forming patches, laminating, sealant applying, and graphics applying steps in registry.

38. A method according to claim 37 wherein the step of applying printed graphics is performed on the central impression drum.