Patterned metal foil laminate and method for making same

• US 5,759,422 A
• Filed: 02/14/1996
• Issued: 06/02/1998
• Est. Priority Date: 02/14/1996
• Status: Expired due to Term

• Current Assignee: Graphic Packaging International LLC (Graphic Packaging International Incorporated)
• Original Assignee: Fort James Corporation (KOCH Industries Incorporated)
• Inventors: Habeger, Charles C., Swiontek, Anthony Joseph, Pollart, Kenneth A., Schmelzer, Michael A.
• Primary Examiner(s): POWELL, WILLIAM A
• Application Number:
  US08/602,576
• Time in Patent Office: 839 Days
• Field of Search: 216/33, 216/35, 216/41, 216/52, 216/65, 216/102, 426/107, 426/113, 426/122, 426/241, 156/224, 156/291, 156/290, 156/250, 156/251, 156/272.8
• US Class Current: 216/35
• CPC Class Codes: B32B 15/04 comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a bituminous or tarry layer B32B11/08; next to a water-setting substance layer B32B13/06; next to a glass layer B32B17/061; next to a cellulosic plastic layer B32B23/042
• CPC Class Codes: B32B 2310/0843 using laser
• CPC Class Codes: B32B 3/22 of spaced pieces not used
• CPC Class Codes: B32B 38/10 Removing layers, or parts of layers, mechanically or chemically
• CPC Class Codes: B65D 2211/00 Anti-theft means
• CPC Class Codes: B65D 2581/344 Geometry or shape factors influencing the microwave heating properties
• CPC Class Codes: B65D 2581/3467 Microwave reactive layer shaped by delamination, demetallizing or embossing
• CPC Class Codes: B65D 2581/3472 Aluminium or compounds thereof
• CPC Class Codes: B65D 2581/3487 Reflection, Absorption and Transmission [RAT] properties of the microwave reactive package
• CPC Class Codes: B65D 81/3446 specially adapted to be heated by microwaves
• CPC Class Codes: G08B 13/2437 Tag layered structure, processes for making layered tags
• CPC Class Codes: G08B 13/244 Tag manufacturing, e.g. continuous manufacturing processes
• CPC Class Codes: G08B 13/2445 Tag integrated into item to be protected, e.g. source tagging
• CPC Class Codes: H05K 3/046 by selective transfer or selective detachment of a conductive layer
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing

Abstract

A patterned metal foil/substrate laminate wherein the pattern is formed by laminating a sheet of metal foil to a substrate by applying an adhesive between the metal foil and substrate in a predetermined pattern which defines areas where adhesive is present and areas where no adhesive is present, cutting the metal foil, as by rotary die cutting or laser cutting, in a pattern which corresponds to the boundaries of the adhesive-containing areas and removing the areas of metal foil which are not adhesively adhered to the substrate. Particularly where the laminate is intended for microwave packaging, the laminate further includes a sheet of barrier layer material, preferably polymer film, laminated to the patterned metal foil layer. The polymer film layer-containing laminate can be formed into a container for packaging food intended for heating in a microwave oven, the container having at least one section, corresponding to the areas of the laminate from which metal foil was removed, that is substantially transparent to microwave energy and at least one section, corresponding to the foil-containing areas of the laminate, that is opaque to microwave energy for shielding food adjacent to the opaque section. Preferably, the metal foil is aluminum foil, desirably unannealed aluminum foil, and the substrate is selected from paper, coated or uncoated paperboard and polymer film.

Claims

1. A method of forming a patterned metal foil/substrate laminate comprising the steps of:

(a) laminating a sheet of metal foil to a substrate by applying an adhesive between said metal foil and said substrate in a pattern which defines areas where adhesive is present and areas where no adhesive is present;

(b) cutting said metal foil in a pattern which corresponds to the boundaries of the adhesive-containing areas; and

(c) removing the areas of metal foil which are not adhesively adhered to said substrate.

2. A method as claimed in claim 1 including the further step of laminating a sheet of barrier layer material to the patterned metal foil layer of said laminate.

3. A method as claimed in claim 2 wherein said barrier layer material is a polymer film.

4. A method as claimed in claim 3 wherein the polymer film is a polyester film.

5. A method as claimed in claims 3 or 4 wherein said polymer film is metallized on one surface thereof and said metallized surface is adhesively adhered to said patterned metal foil layer.

6. A method as claimed in claim 2 wherein said sheet of barrier layer material is laminated to the patterned metal foil layer of said laminate by hot nip lamination.

7. A method as claimed in claim 2 wherein said sheet of barrier layer material is laminated to the patterned metal foil layer of said laminate by extrusion lamination.

8. A method as claimed in claim 2 wherein said sheet of barrier layer material is laminated to the patterned metal foil layer of said laminate by applying a layer of solventless adhesive to said film prior to lamination.

9. A method as claimed in claim 2 wherein said sheet of barrier layer material is laminated to the patterned metal foil layer of said laminate by dry mount adhesive lamination.

10. A method as claimed in claim 2 wherein said sheet of barrier layer material is extrusion coated onto the patterned metal layer of said laminate.

11. A method as claimed in claims 1 or 2 wherein the step of cutting comprises rotary die cutting.

12. A method as claimed in claim 11 wherein said step of rotary die cutting is accomplished using a machined rotary die.

13. A method as claimed in claim 11 wherein said step of rotary die cutting is accomplished using a rotary steel rule die.

14. A method as claimed in claim 13 wherein said die acts against a soft anvil.

15. A method as claimed in claim 14 wherein said soft anvil is corrugated paperboard.

16. A method as claimed in claim 14 wherein said soft anvil is moisturized paperboard.

17. A method as claimed in claims 1 or 2 wherein the step of cutting comprises laser beam cutting.

18. A method as claimed in claim 17 wherein said step of laser beam cutting is accomplished using a Nd:

YAG laser.

19. A method as claimed in claims 1 or 2 wherein said substrate is selected from the group consisting of paper, coated paperboard, uncoated paperboard and polymer film.

20. A method as claimed in claim 19 wherein said polymer film is a polyester film.

21. A method as claimed in claim 1 wherein said substrate is a polymer film and including the further step of adhesively laminating a sheet of paperboard to the patterned metal foil layer of the laminate.

22. A method as claimed in claim 19 wherein said metal foil is aluminum foil.

23. A method as claimed in claim 22 wherein said metal foil is unannealed aluminum foil.

24. A method as claimed in claim 23 including the step of corona treating the surface of said unannealed aluminum foil prior to laminating said aluminum foil to said substrate.

25. A method as claimed in claim 23 including the step of mild flame treating the surface of said unannealed aluminum foil prior to laminating said aluminum foil to said substrate.

26. A method as claimed in claim 22 wherein said metal foil is a diecutting aluminum alloy foil.

27. A method as claimed in claim 1 wherein said areas of unadhered metal foil are removed by vacuum stripping.

28. A method of forming a container for packaging food intended for heating in a microwave oven, the container having at least one section that is opaque to microwave energy for shielding food adjacent to the opaque section, and at least one section that is substantially transparent to microwave energy, said method comprising the steps of:

(a) laminating a sheet of metal foil to a substrate by applying an adhesive between said metal foil and said substrate in a pattern which defines areas where adhesive is present and areas where no adhesive is present;

(b) cutting said metal foil in a pattern which corresponds to the boundaries of the adhesive-containing areas;

(c) removing the areas of metal foil which are not adhesively adhered to said substrate;

(d) laminating a sheet of barrier layer material to the patterned metal foil layer; and

(e) forming said barrier layer/patterned metal foil/substrate laminate into said container with said barrier layer adjacent to the food in the container, the areas of the laminate from which metal foil was removed forming the sections of the container that are transparent to microwave energy and the foil-containing areas of the laminate forming the sections of the container that are opaque to microwave radiation.

29. A method as claimed in claim 28 wherein said metal foil is aluminum foil, said substrate is selected from the group consisting of paper, coated paperboard, uncoated paperboard and polymer film and said barrier layer material is polymer film.

30. A method as claimed in claim 29 wherein said metal foil is unannealed aluminum foil.

31. A method as claimed in claim 30 including the step of corona treating the surface of said unannealed aluminum foil prior to laminating said aluminum foil to said substrate.

32. A method as claimed in claim 30 including the step of mild flame treating the surface of said unannealed aluminum foil prior to laminating said aluminum foil to said substrate.

33. A method as claimed in claim 28 wherein said step of cutting comprises rotary die cutting with a machined rotary die.

34. A method as claimed in claim 28 wherein said step of cutting comprises laser beam cutting.

35. A method as claimed in claim 28 wherein said barrier layer material is polymer film, said polymer film is metallized on one surface thereof and said metallized surface is adhesively adhered to said patterned metal foil layer.

36. A method as claimed in claim 28 wherein said areas of unadhered metal foil are removed by vacuum stripping.

37. A patterned metal foil/substrate laminate wherein said pattern is formed by laminating a sheet of metal foil to a substrate by applying an adhesive between said metal foil and said substrate in a pattern which defines areas where adhesive is present and areas where no adhesive is present, cutting said metal foil in a pattern which corresponds to the boundaries of the adhesive-containing areas and removing the areas of metal foil which are not adhesively adhered to said substrate.

38. A patterned metal foil/substrate laminate as claimed in claim 37 further including a sheet of barrier layer material laminated to the patterned metal foil layer.

39. A patterned metal foil/substrate laminate as claimed in claim 38 wherein said barrier layer material is polymer film.

40. A patterned metal foil/substrate laminate as claimed in claims 37, 38 or 39 wherein said metal foil is aluminum foil and said substrate is selected from the group consisting of paper, coated paperboard, uncoated paperboard and polymer film.

41. A patterned metal foil/substrate laminate as claimed in claim 40 wherein said metal foil is unannealed aluminum foil.

42. A patterned metal foil/substrate laminate as claimed in claim 39 wherein said polymer film is metallized on one surface thereof and said metallized surface is adhesively adhered to said patterned metal foil layer.

43. A container for packaging food intended for heating in a microwave oven, said container having at least one section that is opaque to microwave energy for shielding food adjacent to the opaque section, and at least one section that is substantially transparent to microwave energy, said container formed from a barrier layer/patterned metal foil/substrate laminate with said barrier layer adjacent to the food in the container, wherein said barrier layer/patterned metal foil/substrate laminate is formed by laminating a sheet of metal foil to a substrate by applying an adhesive between said metal foil and said substrate in a pattern which defines areas where adhesive is present and areas where no adhesive is present, cutting said metal foil in a pattern which corresponds to the boundaries of the adhesive-containing areas, removing the areas of metal foil which are not adhesively adhered to said substrate and laminating a sheet of barrier layer material to the patterned metal foil layer, whereby the areas of the laminate from which metal foil was removed form the sections of the container that are transparent to microwave energy and the foil-containing areas of the laminate form the sections of the container that are opaque to microwave radiation.

44. A container as claimed in claim 43 wherein said metal foil is aluminum foil, said substrate is selected from the group consisting of paper, coated paperboard, uncoated paperboard and polymer film and said barrier layer material is polymer film.

45. A container as claimed in claim 44 wherein said metal foil is unannealed aluminum foil.

46. A container as claimed in claim 43 wherein said barrier layer material is polymer film, said polymer film is metallized on one surface thereof and said metallized surface is adhesively adhered to said patterned metal foil layer.