Non-stick polymer coated aluminum foil

• US 6,423,417 B1
• Filed: 05/24/2000
• Issued: 07/23/2002
• Est. Priority Date: 05/24/2000
• Status: Expired due to Term

• Current Assignee: Reynolds Consumer Products Incorporated
• Original Assignee: Reynolds Metals Company (Howmet Aerospace, Inc.)
• Inventors: Robbins, Bruce
• Primary Examiner(s): Dawson, Robert
• Assistant Examiner(s): ZIMMER, MARC S
• Application Number:
  US09/576,886
• Time in Patent Office: 790 Days
• Field of Search: 427/387, 427/379, 427/178, 427/388.1, 428/447, 428/450, 428/689, 524/323, 524/267, 524/736, 524/738
• US Class Current: 428/450
• CPC Class Codes: B05D 3/0209 Multistage baking
• CPC Class Codes: B05D 5/08 to obtain an anti-friction or anti-adhesive surface rendering particulate materials free-flowing in general, e.g. making them hydrophobic B01J2/30
• CPC Class Codes: B05D 7/14 to metal, e.g. car bodies involving a chemical reaction between the metal and the coating C23
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

A non-stick polymer coated aluminum foil and method of making it. The polymer coating composition comprises a silicone resin, a silicone release agent, a silicone curing agent, a hindered phenol antioxidant and a solvent. The method of making the non-stick polymer coated aluminum foil includes applying the polymer coating composition on at least a portion of one side of the aluminum foil and partially curing the coating composition to allow handling and future processing of the coated aluminum foil without blocking of the coating composition. The curing of the coating composition is completed by heating the coated aluminum foil in bulk.

Claims

1. A non-stick, polymer coated aluminum foil comprising:

an aluminum foil; and

a non-stick, polymer coating bonded on at least a portion of one side of the aluminum foil wherein said polymer coating comprises a non-stick, coating composition comprising,

a silicone resin selected from the group consisting of dimethyl polysiloxanes, polyester-modified methylphenyl polysiloxanes, and hydroxyl functional silicone resins;

a silicone release agent; and

a hindered phenol antioxidant.

2. The non-stick, polymer coated aluminum foil of claim 1, wherein said silicone release agent is a polydimethylsiloxane liquid compound.

3. The non-stick, polymer coated aluminum foil of claim 1, wherein said hindered phenol is butylated hydroxy toluene.

4. The non-stick, polymer coated aluminum foil of claim 1, wherein said hindered phenol is used in an amount of from about 0.1 to about 4.0 percent by weight based on the weight of the silicone resin.

5. The non-stick, polymer coated aluminum foil of claim 1, wherein said silicone release agent is used in an amount of from about 0.1 to about 5.0 percent by weight, and said hindered phenol is used in amount of from about 0.1 to about 4.0 percent by weight based on the weight of the silicone resin.

6. A method of making a coated aluminum foil comprising:

applying a curable coating composition on at least a portion of one side of an aluminum foil to form a coated aluminum foil; and

partially curing the coating composition in a heating step by heating the coated aluminum foil at a sufficiently high temperature to allow subsequent completion of the curing of the coated aluminum foil in bulk without blocking.

7. The method of claim 6, wherein said first heating step further comprises passing the coated aluminum foil through an oven in a continuous process at a throughput rate and at an oven temperature sufficient to allow the temperature of the metal surface of the aluminum foil to reach a temperature of at least 480°

F. as the coated aluminum foil exits the oven.

8. The method of claim 6, further comprising the steps of winding the partially cured coated aluminum foil in a coil;

cooling the aluminum foil in coil form; and

a second heating step comprising heating the aluminum foil in coil form to a temperature and for a time sufficient to complete the curing of the coating composition.

9. The method of claim 6, wherein said coating composition is applied on said aluminum foil in an amount of from about 0.025 lbs. to about 0.040 lbs. per 3,000 square feet.

10. The method of claim 6, wherein said cooling of the aluminum foil in coil form is done gradually by air or liquid.

11. The method of claim 6, wherein said curable coating composition comprises:

a silicone resin, a silicone release agent, a silicone resin curing agent, a hindered phenol antioxidant and a solvent.

12. The method of claim 8, wherein said second heating step includes heating the aluminum foil in coil form to a temperature of from about 350°

F. to about 500°

F., for about 5 hours to about 1 hour inside an oven.

13. The method of claim 8, wherein said second heating step includes heating the aluminum foil in coil form to a temperature of at least 425°

F. for about 3 hours.

14. The method of claim 11, wherein said silicone resin is selected from the group consisting of dimethyl polysiloxanes, polyester-modified methylphenyl polysiloxanes and hydroxyl functional silicone resins.

15. The method of claim 11, wherein said hindered phenol antioxidant is butylated hydroxy toluene.

25. The non-stick, polymer coated aluminum foil formed by the method of claim 7.

26. The non-stick, polymer coated aluminum foil wherein said non-stick polymer coating is formed by the method of claim 8.

16. A method of making a non-stick, coated aluminum foil comprising:

applying a curable coating composition on at least a portion of one side of an aluminum foil;

partially curing the coating composition in a first heating step sufficiently to allow winding the coated aluminum foil in a coil without blocking of the coating composition; and

completing the curing of the coating composition in a second heating step of the aluminum foil in coil form.

17. The method of claim 16, wherein said partial curing step includes passing the coated aluminum foil through an oven in a continuous process at a throughput rate which is the same as the throughput rate of an upstream process for making the aluminum foil and at an oven temperature sufficient to allow the metal surface temperature of the aluminum foil to reach a temperature of at least 480°

F. as it exits the oven.

18. The method of claim 16, wherein completing the curing includes heating the aluminum foil in coil form in bulk inside an oven.

19. The method of claim 16, wherein completing the curing includes heating the aluminum foil in coil form to a temperature of from about 350 to about 500°

F., for about 5 to about 1 hour.

20. The method of claim 16, wherein completing the curing includes heating the aluminum foil in coil form to a temperature of at least 425°

F. for about 3 hours.

21. The method of claim 16, further comprising gradual cooling of the partially cured coated aluminum foil by air or liquid.

22. The method of claim 16, wherein the coating composition is applied using a graver cylinder.

23. The method of claim 16, wherein said curable coating composition comprises:

a silicone resin, a silicone release agent, a silicone curing agent, a hindered phenol antioxidant and a solvent.

24. The method of claim 23, wherein the hindered phenol antioxidant is butylated hydroxy toluene.

27. A method of making a coated aluminum foil comprising:

applying a curable coating composition on at least a portion of one side of an aluminum foil to form a coated aluminum foil;

partially curing the coating composition in a first heating step by heating the coated aluminum foil at a sufficiently high temperature to allow winding the coated aluminum foil in a coil without blocking of the coating composition;

cooling the aluminum foil in coil form; and

heating the aluminum foil in coil form in a second heating step to a temperature and for a time sufficient to complete the curing of the coating composition.

28. The method of claim 27, wherein said first heating step further comprises passing the coated aluminum foil through an oven in a continuous process at a throughput rate and at an oven temperature sufficient to allow the temperature of the metal surface of the aluminum foil to reach a temperature of at least 480°

F. as the coated aluminum foil exits the oven.

29. The method of claim 27, wherein said coating composition is applied on said aluminum foil in an amount of from about 0.025 lbs. to about 0.040 lbs. per 3,000 square feet.

30. The method of claim 27, wherein said cooling of the aluminum foil in coil form is done gradually by air or liquid.

31. The method of claim 27, wherein said curable coating composition comprises a silicone resin, a silicone release agent, a silicone resin curing agent, a hindered phenol antioxidant and a solvent.

32. The method of claim 31, wherein said silicone resin is selected from the group consisting of dimethyl polysiloxanes, polyester-modified methylphenyl polysiloxanes and hydroxyl functional silicone resins.

33. The method of claim 31, wherein said hindered phenol is butylated hydroxy toluene.

34. The method of claim 27, wherein said second heating step includes heating the aluminum foil in coil form to a temperature of from about 350°

F. to about 500°

F., for about 5 hours to about 1 hour inside an oven.

35. The method of claim 27, wherein said second heating step includes heating the aluminum foil in coil form to a temperature of at least 425°

F. for about 3 hours.

36. A method of making a non-stick, coated aluminum foil comprising:

applying a curable coating composition on at least a portion of one side of an aluminum foil;

partially curing the coating composition in a first heating step by heating the coated aluminum foil at a sufficiently high temperature to allow subsequent completion of the curing of the coated aluminum foil in bulk without blocking;

winding the coated aluminum foil in a coil; and

completing the curing of the coating composition by heating the aluminum foil in coil form in bulk.

37. The method of claim 36, wherein said partial curing step includes passing the coated aluminum foil through an oven in a continuous process at a throughput rate which is the same as the throughput rate of an upstream process for making the aluminum foil and at an oven temperature sufficient to allow the metal surface temperature of the aluminum foil to reach a temperature of at least 480°

F. as it exits the oven.

38. The method of claim 36, wherein completing the curing includes heating the aluminum foil in coil form to a temperature of from about 350 to about 500°

F., for about 5 hours to about 1 hour.

39. The method of claim 36, wherein completing the curing includes heating the aluminum foil in coil form to a temperature of at least 425°

F. for about 3 hours.

40. The method of claim 36, wherein the coating composition is applied using a gravure cylinder.

41. The method of claim 36, wherein said curable coating composition comprises a silicone resin, a silicone release agent, a silicone curing agent, a hindered phenol antioxidant and a solvent.