Coated products

• US 6,217,732 B1
• Filed: 09/17/1998
• Issued: 04/17/2001
• Est. Priority Date: 09/23/1997
• Status: Expired due to Fees

• Current Assignee: ABB Lummus Global Inc.
• Original Assignee: ABB Business Services, Inc. (ABB Limited)
• Inventors: Schuh, Lothar, Herschel, Philipp, Gutzeit, Heidemarie
• Primary Examiner(s): Mayekar, Kishor
• Application Number:
  US09/156,023
• Time in Patent Office: 943 Days
• Field of Search: 204/490, 204/491
• US Class Current: 204/490
• CPC Class Codes: B01J 35/58 Fabrics or filaments
• CPC Class Codes: B01J 37/342 of electric, magnetic or electromagnetic fields, e.g. for magnetic separation
• CPC Class Codes: C25D 13/00 Electrophoretic coating characterised by the process C25D15/00 takes precedence; compositions for electrophoretic coating C09D5/44
• CPC Class Codes: C25D 13/12 characterised by the article coated

Abstract

A product comprised of a three dimensional network of material is coated with a particulate support. The coating may be applied by an electrophoretic coating procedure to apply a particulate coating on the surface or into the interior portions of such three dimensional network of material. In one embodiment, the particles are a catalyst or a catalyst precursor or a catalyst support to thereby provide a catalyst structure in which catalyst may be supported as a coating in the interior and on the exterior of a three-dimensional network of material having a high void volume. Edge effects may be reduced by control or disruption of field lines during the coating. In addition, larger particles may be electrophoretically coated onto a product by the use of smaller particles which function as a “glue”.

Claims

1. A process for applying a coating to a product comprising a porous three-dimensional network of material, comprising:

electrophoretically coating both the exterior and at least a portion of the interior of said porous three-dimensional network of material comprising a plurality of layers of fibers by electrophoretically coating said network by use of a coating bath comprising a liquid and particles to be applied as a coating, said particles being suspended in the liquid, said particles comprising at least one member selected from the group consisting of a catalyst support, an unsupported catalyst precursor, a supported catalyst, and an unsupported catalyst, said particles including at least first and second portions, said first portion having an average particle size of at least 0.5 micron and the second portion has an average particle size of less than 150 nanometers, said second portion of said particles being present in an amount effective to form an electrophoretic coating on said material comprising at least said first and second portions of particles, and wherein the void volume of the product which is coated is at least 45%.

2. The process of claim 1 wherein the three dimensional network of material has a thickness of at least 50 microns and the fibers of the network comprise fibers with a diameter or thickness of less than 100 microns.

3. The process of claim 1 wherein said electrophoretically coating of said material comprises electrophoretically coating said material in an electrophoretic coating bath by application of a potential between a first electrode comprising said material and a second electrode, said electrophoretic coating being effected with disrupted electric field lines between the first and second electrodes to reduce the difference in thickness between the coating on the edges of said material and other portions of said material.

4. The process of claim 3 wherein said first and second electrodes are placed at a distance from each other which produces non-homogeneous field lines between the first and second electrode.

5. The process of claim 4 wherein said second electrode is comprised of a plurality of separately spaced electrodes to produce the non-homogeneous field lines.

6. The process of claim 3 wherein a dielectric material having an opening therein is between the first and second electrodes during said coating;

said material having a dielectric constant which differs from the dielectric constant of the bath.

7. The process of claim 3 wherein the cross-sectional area of the first and second electrodes and the cross-sectional area of the coating bath between the first and second electrodes are essentially equal to each other.

8. The process of claim 1 wherein said second portion has an average particle size of at least 2 nanometers.

9. The process of claim 8 wherein said second portion has an average particle size of from 20 nanometers to 40 nanometers.

10. The process of claim 1 wherein said first portion has an average particle size of at least 1.0 micron.

11. The process of claim 10 wherein said first portion has an average particle size that does not exceed 20 microns.

12. The process of claim 1 wherein said coating is applied to the interior of said material and penetrates into the interior of the material to a depth of at least 5 microns.

13. The process of claim 1 wherein said fibers have a thickness of less than 500 microns.

14. The process of claim 13 wherein said fibers have a thickness of less than 100 microns.

15. The process of claim 14 wherein said fibers have a thickness of less that 30 microns.

16. The process of claim 1 wherein said product which is coated has an average void opening of at least 10 microns.

17. The process of claim 16 wherein the said product which is coated has an average void opening of at least 20 microns.

18. The process of claim 1 wherein said product which is coated has a void volume of at least 55%.

19. The process of claim 18 wherein said product which is coated has a void volume of at least 65%.

20. The process of claim 19 wherein said product which is coated has a void volume which does not exceed 95%.

21. The process of claim 20 wherein said product which is coated has a void volume which does not exceed 90%.

22. The process of claim 1 wherein said material has a thickness of at least 5 microns.

23. The process of claim 22 wherein said material has a thickness which does not exceed 10 mm.

24. The process of claim 23 wherein said material has a thickness of at least 50 microns and does not exceed 2 mm.

25. The process of claim 1 wherein said fibers in each layer of said plurality of layers of fibers is oriented randomly.

26. A process for applying a coating to a product comprising a porous three-dimensional network of material, comprising:

electrophoretically coating both the exterior and at least a portion of the interior of said porous three-dimensional network of material comprising a plurality of layers of fibers by applying particles having an average particle size which does not exceed 100 microns to said product by electrophoretic coating to coat the exterior of said product and at least a portion of the interior of said product, to form a particulate coating on said fibers, said particles comprising at least one member selected from the group consisting of a catalyst support, an unsupported catalyst precursor, a supported catalyst, and an unsupported catalyst, and wherein the void volume of the product which is coated is at least 45%.

27. The process of claim 26 wherein the particles are a catalyst support that includes a catalyst or catalyst precursor comprising fibers with a diameter or thickness of less than 100 microns.

28. The process of claim 26 wherein said particles have an average particle size which does not exceed 10 microns.

29. The process of claim 26 wherein said electrophoretically coating of said material comprises electrophoretically coating said material in an electrophoretic coating bath by application of a potential between a first electrode comprising said material and a second electrode, said electrophoretic coating being effected with disrupted electric field lines between the first and second electrodes to reduce the difference in thickness between the coating on the edges of said material and other portions of said material.

30. The process of claim 26 wherein said coating is applied to the interior of said material and penetrates into the interior of the material to a depth of at least 5 microns.

31. The process of claim 26 wherein said fibers have a thickness of less than 500 microns.

32. The process of claim 31 wherein said fibers have a thickness of less than 100 microns.

33. The process of claim 32 wherein said fibers have a thickness of less than 30 microns.

34. The process of claim 26 wherein said product which is coated has a void volume of at least 55%.

35. The process of claim 34 wherein said product which is coated has a void volume of at least 65%.

36. The process of claim 35 wherein said product which is coated has a void volume which does not exceed 95%.

37. The process of claim 36 wherein said product which is coated has a void volume which does not exceed 90%.

38. The process of claim 26 wherein said material has a thickness of at least 5 microns.

39. The process of claim 38 wherein said material has a thickness which does not exceed 10 mm.

40. The process of claim 39 wherein said material has a thickness of at least 50 microns and does not exceed 2 mm.

41. The process of claim 26 wherein said fibers in each layer of said plurality of layers of fibers is oriented randomly.