Microwave cooking packages and methods of making thereof

• US 20080081095A1
• Filed: 10/31/2007
• Published: 04/03/2008
• Est. Priority Date: 02/09/2004
• Status: Active Grant

• Current Assignee: Graphic Packaging International LLC (Graphic Packaging International Incorporated)
• Original Assignee: Graphic Packaging International Incorporated
• Inventors: Robinson, Richard, Lafferty, Terrence, Bohrer, Timothy, Middleton, Scott, O'Hagan, Brian, Cole, Lorin, Wnek, Patrick
• Granted Patent: US 8,440,275 B2
• Time in Patent Office: Days
• US Class Current: 426/107
• CPC Class Codes: B65D 2581/3472 Aluminium or compounds thereof
• CPC Class Codes: B65D 2581/3477 Iron 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 65/14 with areas coated with adhesive
• CPC Class Codes: B65D 81/03 Wrappers or envelopes with shock-absorbing properties, e.g. bubble films for thermal insulating purposes B65D81/3888
• CPC Class Codes: B65D 81/3453 Rigid containers, e.g. trays, bottles, boxes, cups
• CPC Class Codes: B65D 81/3461 Flexible containers, e.g. bags, pouches, envelopes
• CPC Class Codes: B65D 81/3893 formed with double walls, i.e. hollow
• CPC Class Codes: F25D 23/065 Details
• CPC Class Codes: H05B 6/6408 Supports or covers specially adapted for use in microwave heating apparatus
• CPC Class Codes: H05B 6/6494 for cooking
• CPC Class Codes: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1303 Paper containing [e.g., paperboard, cardboard, fiberboard, etc.]
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/1359 Three or more layers [continuous layer]
• CPC Class Codes: Y10T 428/139 Open-ended, self-supporting conduit, cylinder, or tube-type article

Abstract

A microwave insulating material includes a dimensionally stable support, a patterned adhesive layer overlying at least a portion of the support, a polymer film layer overlying the patterned adhesive layer, and a plurality of expandable cells disposed between the support and the polymer film layer and defined by the patterned adhesive layer, wherein the expandable cells vary in size. A self-sealing microwave package includes a sheet of insulating material including a first surface, and a thermally activatable adhesive applied to at least a portion of the first surface.

Claims

1. A package with self-forming insulating walls, comprising:

a tray for supporting a food item;

a flap joined to the tray along a fold line; and

an insulating microwave material overlying at least a portion of the tray and at least a portion of the flap, the insulating microwave material being joined to the flap, wherein the insulating microwave material includes

a microwave energy interactive material supported on a first polymer film layer,

a moisture-containing layer joined to the microwave energy interactive material, and

a second polymer film layer joined to the moisture-containing layer in a predetermined pattern, thereby defining a plurality of expandable cells between the moisture-containing layer and the second polymer film layer.

2. The package of claim 1, wherein upon exposure to microwave energy, the expandable cells are adapted to inflate, thereby causing the flap to hinge toward the tray along the fold line.

3. The package of claim 1, wherein

the flap includes a peripheral edge, and

the insulating microwave material extends substantially to the peripheral edge of the flap.

4. The package of claim 1, wherein

the flap includes a peripheral edge,

the insulating microwave material extends beyond the peripheral edge of the flap.

5. The package of claim 1, wherein

the flap is a first flap,

the package includes a second flap, third flap, and fourth flap joined to the tray along respective fold lines, and

the insulating microwave material overlies at least a portion of each of the second flap, third flap, and fourth flap.

6. An insulating microwave material comprising:

a susceptor film comprising a microwave energy interactive material supported on a first polymer film;

a dimensionally stable substrate joined to the microwave energy interactive material; and

a second polymer film at least partially covered by a layer of amorphous polyethylene terephthalate,

wherein the amorphous polyethylene terephthalate is selectively bonded to the dimensionally stable substrate, thereby defining a plurality of substantially closed cells adjacent to the dimensionally stable substrate.

7. The insulating microwave material of claim 6, wherein the dimensionally stable substrate comprises a moisture-containing material.

8. The insulating microwave material of claim 7, wherein the moisture-containing material comprises paper or paperboard.

9. The insulating microwave material of claim 6, wherein the microwave energy interactive material comprises aluminum.

10. The insulating microwave material of claim 6, wherein at least one of the first polymer film and the second polymer film comprises polyethylene terephthalate.

11. The insulating microwave material of claim 6, wherein the first polymer film and the second polymer film each comprise polyethylene terephthalate.

12. The insulating microwave material of claim 6, wherein the closed cells are substantially resistant to vapor migration.

13. The insulating microwave material of claim 6, wherein the closed cells inflate upon exposure to microwave energy.

14. The insulating microwave material of claim 6, wherein the cells are approximately equal in size.

15. The insulating microwave material of claim 6, wherein at least some of the expandable cells vary in size from at least some other of the expandable cells.

16. The insulating microwave material of claim 6, further comprising an oxygen barrier layer.

17. An insulating microwave material comprising:

a susceptor film comprising a thin layer of microwave energy interactive material supported on a first polymer film;

a moisture-containing substrate joined to the layer of microwave energy interactive material; and

a second polymer film including a coating of amorphous polyethylene terephthalate on a first side of the second polymer film,

wherein

the first side of the second polymer film is in a facing relationship with the moisture-containing substrate,

the coating of amorphous polyethylene terephthalate is selectively bonded to the moisture-containing substrate to define a plurality of closed cells between the moisture-containing substrate and the second polymer film, and

the closed cells are substantially resistant to vapor migration.

18. The insulating microwave material of claim 17, wherein the microwave energy interactive material comprises aluminum.

19. The insulating microwave material of claim 17, wherein at least one of the first polymer film and the second polymer film comprises polyethylene terephthalate.

20. The insulating microwave material of claim 17, wherein the moisture-containing substrate releases water vapor upon exposure to microwave energy, thereby inflating the closed cells.

21. An insulating microwave material comprising:

a layer of microwave energy interactive material supported on a first polymer film;

a dimensionally stable substrate joined to the layer of microwave energy interactive material;

a second polymer film; and

a layer of amorphous polyethylene terephthalate overlying the second polymer film in a facing relationship with the dimensionally stable substrate,

wherein the layer of amorphous polyethylene terephthalate defines a plurality of bonded areas and unbonded areas between the dimensionally stable substrate and the second polymer film.

22. The insulating microwave material of claim 21, wherein the layer of microwave energy interactive material heats upon impingement of microwave energy.

23. The insulating microwave material of claim 21, wherein the layer of microwave energy interactive material comprises a metal.

24. The insulating microwave material of claim 21, wherein at least one of the first polymer film and the second polymer film comprises polyethylene terephthalate.

25. The insulating microwave material of claim 21, wherein the unbonded areas comprise a plurality of inflatable cells defined by the bonded areas.

26. The insulating microwave material of claim 25, wherein the inflatable cells are substantially resistant to vapor migration along the bonded areas.

27. The insulating microwave material of claim 25, wherein

the dimensionally stable substrate contains moisture, and

upon exposure to microwave energy, the dimensionally stable substrate releases water vapor, thereby inflating the inflatable cells.

28. The insulating microwave material of claim 25, wherein at least some of the inflatable cells vary in size from at least some other of the inflatable cells.

29. A method of making an insulating microwave material, comprising:

joining a dimensionally stable substrate to a layer of microwave energy interactive material supported on a first polymer film, such that the microwave energy interactive material is disposed between the first polymer film and the dimensionally stable substrate;

providing a second polymer film including a first side, the second polymer film including a layer of amorphous polyethylene terephthalate overlying at least a portion of the first side;

arranging the dimensionally stable substrate in a superposed, facing relationship with the layer of amorphous polyethylene terephthalate; and

contacting the arranged layers with a thermo-mechanical bonding element in a patterned configuration, such that the amorphous polyethylene terephthalate is heated above a softening temperature and bonds to the dimensionally stable substrate in the patterned configuration,

wherein the patterned configuration of bonding defines a plurality of expandable insulating cells between the dimensionally stable substrate and the second polymer film.

30. The method of claim 29, further comprising selecting the patterned configuration of bonding to define at least some expandable insulating cells that vary in size from at least some other expandable insulating cells.

31. The method of claim 29, further comprising selecting the patterned configuration of bonding to define a plurality of expandable insulating cells arranged to form a periphery and a plurality of expandable insulating cells positioned within the periphery, wherein the expandable insulating cells that form the periphery differ in size from the expandable insulating cells within the periphery.

32. The method of claim 31, further comprising selecting the patterned configuration of bonding such that the expandable insulating cells that form the periphery are larger than the expandable insulating cells within the periphery.

33. A method of forming a microwave energy interactive insulating container, comprising:

providing a first polymer film, a layer of microwave energy interactive material, and a dimensionally stable substrate in a layered configuration with the microwave energy interactive material disposed between the first polymer film and the dimensionally stable substrate;

providing a second polymer film including a layer of amorphous polyethylene terephthalate overlying at least a portion of a first side of the second polymer film;

positioning the second polymer film adjacent to the dimensionally stable substrate with the layer of amorphous polyethylene terephthalate in a facing relationship with the dimensionally stable substrate to form an arrangement of layers;

placing the arrangement of layers between a punch section and a cavity section of a thermo-mechanical bonding device, wherein at least one of the punch section and the cavity section includes a bonding element; and

engaging the punch section and the cavity section with the arranged layers therebetween, thereby bringing the bonding element into contact with the arranged layers,

wherein bringing the bonding element into contact with the arranged layers causes the amorphous polyethylene terephthalate to adhere to the dimensionally stable substrate.

34. The method of claim 33, wherein adhering the amorphous polyethylene terephthalate to the dimensionally stable substrate defines a plurality of closed cells between the dimensionally stable substrate and the layer of amorphous polyethylene terephthalate.

35. The method of claim 34, wherein the closed cells are adapted to inflate in response to microwave energy.

36. The method of claim 33, wherein

the bonding element is a first bonding element of a plurality of bonding elements, and

the bonding elements are arranged to define a plurality of closed cells between the dimensionally stable substrate and the second polymer film.

37. The method of claim 36, wherein the bonding elements are arranged to define some closed cells that vary in size from at least some other closed cells.

38. The method of claim 33, wherein

the bonding element is a first bonding element of a plurality of bonding elements,

the punch section and the cavity section each include at least one bonding element of the plurality of bonding elements, and

the bonding elements in the punch section and the cavity section are in substantial alignment.

39. The method of claim 33, wherein

the bonding element is a first bonding element of a plurality of bonding elements,

the punch section and the cavity section each include at least one bonding element of the plurality of bonding elements, and

the bonding elements in the punch section and the cavity section are not in substantial alignment.

40. The method of claim 33, wherein only the punch section includes the bonding element.

41. The method of claim 33, wherein only the cavity section includes the bonding element.

42. The method of claim 33, wherein the cavity section is shaped to define the outer surface of the container and the punch section is shaped to define the inner surface of the container.

43. An insulating microwave material having barrier properties comprising:

a layer of microwave energy interactive material supported on a first polymer film;

a moisture-containing substrate joined to the layer of microwave energy interactive material;

a second polymer film including a coating of amorphous polyethylene terephthalate on a first side of the second polymer film; and

a third polymer film adapted to reduce the transmission of oxygen through the insulating microwave material.

44. The insulating microwave material of claim 43, wherein the third polymer film comprises ethylene vinyl alcohol, nylon 66, or a combination thereof.

45. The insulating microwave material of claim 43, wherein the oxygen barrier layer is disposed between the moisture-containing substrate and the second film layer.

46. The insulating microwave material of claim 43, wherein the oxygen barrier layer is disposed between the layer of microwave energy interactive material and the moisture-containing substrate.

47. The insulating microwave material of claim 43, wherein the oxygen barrier layer is superposed with the first polymer film distal the moisture-containing substrate.

48. The insulating microwave material of claim 43, wherein the oxygen barrier layer is superposed with the second film layer distal the dimensionally stable substrate.

49. A package for heating, browning, and/or crisping a food item in a microwave oven, comprising:

a tray including a bottom panel and a plurality of substantially upstanding walls defining an interior space for receiving a food item, the bottom panel including an interior surface facing the interior space and an exterior surface opposite the interior surface;

a lid foldably joined to a first wall of the plurality of substantially upstanding walls, the lid including a interior surface facing the interior space; and

an insulating microwave material including a plurality of expandable cells overlying at least a portion of the interior surface of the lid,

wherein the lid is adapted to be folded away from the interior space and brought into a superposed relationship with the bottom panel, such that the insulating microwave material is distal the bottom panel.

50. The package of claim 49, wherein the insulating microwave material includes

a microwave energy interactive material supported on a first polymer film layer,

a moisture-containing layer joined to the microwave energy interactive material, and

a second polymer film layer joined to the moisture-containing layer in a predetermined pattern, thereby defining the plurality of expandable cells between the moisture-containing layer and the second polymer film layer.

51. The package of claim 49, wherein the lid includes a tab adapted to be received in a slot in the bottom panel with the package in an open configuration.

52. The package of claim 49, wherein

the plurality of upstanding walls includes a second wall opposite the first wall, and

the lid includes a tab adapted to be received in a slot in the second panel with the package in a closed configuration.

53. The package of claim 49, further comprising a microwave energy interactive material overlying the interior surface of the bottom panel.

54. A method of packaging a food item, comprising:

unwinding onto a moving belt a first web of insulating microwave material;

placing a food item having a leading edge onto the first web of insulating microwave material;

unwinding over the food item a second web of insulating microwave material;

advancing the leading edge of the food item to an integrated heat seal and cutoff tool including

a heat seal tool, and

a blade coaxially aligned with the heat seal tool; and

actuating the heat seal tool, thereby bonding the second web of insulating microwave material to the first web of insulating microwave material, and

cutting through the first web of insulating microwave material and the second web of insulating microwave material.

55. The method of claim 54, wherein actuating the heat seal tool comprises

bringing the heat seal tool into contact with the second web of insulating microwave material, thereby causing the second web of insulating microwave material to contact the first web of insulating microwave material,

forming a thermo-mechanical bond between the first web of insulating microwave material and the second web of insulating microwave material,

extending the blade toward the bonded first web of insulating microwave material and the second web of insulating microwave material,

cutting the bonded first web of insulating microwave material and the second web of insulating microwave material, and

withdrawing the blade into the heat seal tool.

56. The method of claim 54, wherein the integrated heat seal and cutoff tool further includes a plate supporting the first web of insulating microwave material, the plate being configured to receive the blade when the integrated heat seal and cutoff tool is actuated.

57. The method of claim 54, wherein

the heat seal tool is a first heat seal tool, and

the integrated heat seal and cutoff tool further comprises a second heat seal tool supporting the first web of insulating microwave material, the second heat seal tool being configured to receive the blade when the integrated heat seal and cutoff tool is actuated.

58. A package for heating, browning, and/or crisping a food item in a microwave oven, comprising:

a base, a lid, and a plurality of walls, each having an interior surface; and

an insulating microwave material covering at least a portion of the interior surface of at least one of the base, lid, and walls, wherein the insulating microwave material includes

a microwave energy interactive material supported on a first polymer film layer,

a moisture-containing layer joined to the microwave energy interactive material, and

a second polymer film layer joined to the moisture-containing layer in a predetermined pattern, thereby defining a plurality of expandable cells between the moisture-containing layer and the second polymer film layer, at least one expandable cell varying in size from at least one other expandable cell,

wherein the expandable cells are adapted to inflate upon sufficient exposure to microwave energy.

59. The package of claim 58, wherein the expandable cells are arranged to provide an insulating region, a non-insulating region, or any combination of insulating regions and non-insulating regions within the package.

60. The package of claim 58, wherein at least some of the expandable cells are at least partially expanded prior to heating the food item in a microwave oven.