Claims
- 1. A process for coating a metal substrate, comprising the steps of:(a) applying a first powder coating composition to a surface of the metal substrate; (b) applying a first infrared radiation at a first power density of 30 kilowatts per meter squared or less and optionally a first air simultaneously to the first coating composition for a first period of at least or about 90 seconds, a first temperature of the metal substrate being increased at a first rate ranging from about 0.3° C. per second to about 1.25° C. per second to achieve a first peak metal temperature ranging from about 125° C. to about 200° C., such that a sintered first coating is formed upon the surface of the metal substrate; (c) applying a second powder coating composition over the first powder coating; and (d) applying a second infrared radiation at a second power density of 30 kilowatts per meter squared or less and a second air simultaneously to the second coating composition for a second period of at least or about 2 minutes, a second temperature of the metal substrate being increased at a second rate ranging from about 0.8° C. per second to about 1.3° C. per second to achieve a second peak metal temperature of the substrate ranging from about 125° C. to about 175° C., such that a powder layered system is formed upon the surface of the metal substrate.
- 2. The process according to claim 1, wherein the metal substrate is selected from the group consisting of iron, steel, aluminum, zinc, magnesium, alloys and combinations thereof.
- 3. The process according to claim 1, wherein the metal substrate is an automotive body component.
- 4. The process accordingly to claim 1, wherein the first coating composition is a basecoating composition, and the second coating composition is a topcoating composition.
- 5. The process according to claim 1, wherein the first air is applied to the first coating composition simultaneously with the first infrared radiation in the step (b).
- 6. The process according to claim 5, wherein the first air has a first air temperature ranging from about 65° C. to about 140° C. in the step (b).
- 7. The process according to claim 5, wherein the first air is applied at a first velocity ranging from about 0.25 meters per second to about 1.0 meter per second in the step (b).
- 8. The process according to claim 1, wherein the first period ranges from about 90 seconds to about 480 seconds in the step (b).
- 9. The process according to claim 1, wherein the first infrared radiation is emitted at the first power density ranging from about 4.5 kilowatts per square meter to about 14 kilowatts per square meter in the step (b).
- 10. The process according to claim 1, wherein the first infrared radiation and the second infrared radiation is emitted at a wavelength ranging from about 0.7 micrometers to about 20 micrometers in both the steps (b) and (d), respectively.
- 11. The process according to claim 10, wherein the first infrared radiation and the second infrared radiation is emitted at the wavelength ranging from about 0.7 micrometers to about 4 micrometers in both the steps (b) and (d), respectively.
- 12. The process according to claim 1, wherein the second power density of the second infrared radiation ranges from about 4.5 kilowatts about 14 kilowatts per square meter in the step (d).
- 13. The process according to claim 1, wherein the second air in the step (d) has a second air temperature ranging from about 90° C. to about 200° C.
- 14. The process according to claim 13, wherein the second air in the step (d) has the second air temperature ranging from about 120° C. to about 150° C.
- 15. The process according to claim 1, wherein the second air has a second air velocity ranging from about 0.5 meters per second to about 13 meters per second per second in the step (d).
- 16. The process of claim 15, wherein the second air velocity is about 0.5 meters per second during a first portion of the second period, and the second air velocity is increased to up to about 13 meters per second during a second portion of the second period in the step (d).
- 17. The process of claim 16, wherein a first dwell time in the first portion of the second period and a second dwell time in the second portion of the second period are approximately equal in the step (d).
- 18. The process of claim 16, wherein the second air velocity is increased to up to about 13 meters per second during the second portion of the second period at a curvilinear rate.
- 19. The process according to claim 1, wherein the second air is applied to the second coating composition at a second air velocity ranging from about 0.5 to about 3 meters per second in the step (d).
- 20. The process according to claim 1, wherein the second period ranges from about 2 minutes to about 20 minutes in the step (d).
- 21. The process according to claim 1, further comprising an additional step (b′) of applying hot air having a temperature ranging from about 110° C. to about 140° C. to the sintered first coating to achieve a peak metal temperature ranging from about 125° C. to about 175° C. for a period of at least or about 10 minutes after step (b), such that a cured first coat is formed upon the surface of the metal substrate.
- 22. The process according to claim 21, wherein additional step (b′) further comprises applying infrared radiation to the first coating simultaneously while applying the hot air.
- 23. The process according to claim 1, further comprising an additional step (b″) of cooling the metal substrate to a temperature ranging from about 25° C. to about 32° C. between the steps (b) and (c) prior to applying the second powder coating composition.
- 24. The process according to claim 1, further comprising an additional step (e) of curing the second powder coating composition after application over the first coating.
- 25. The process according to claim 24, wherein the additional step (e) further comprises curing the first coating composition and the second powder coating composition after application of the second powder coating composition over the first coating.
- 26. A process for coating a substrate, comprising the steps of:(a) applying a first powder coating composition to a surface of the substrate; (b) applying a first infrared radiation at a first power density of 30 kilowatts per meter squared or less and optionally a first air simultaneously to the first coating composition for a first period of at least or about 90 seconds such that a sintered first coating is formed upon the surface of the substrate; (c) applying a second powder coating composition over the first coating; and (d) applying a second infrared radiation at a second power density of 30 kilowatts per meter squared or less and a second air at a second air velocity ranging from about 0.5 to about 13 meters per second simultaneously to the second coating composition for a second period of at least or about 2 minutes, such that a powder layered system is formed upon the surface of the substrate.
- 27. The process accordingly to claim 1, wherein the first coating composition is a basecoating composition, and the second coating composition is a topcoating composition.
- 28. The process according to claim 26, wherein the first air is applied at a first velocity ranging from about 0.25 meters per second to about 1.0 meter per second in the step (b).
- 29. The process according to claim 26, wherein the second air velocity ranges from about 0.5 to about 3 meters per second in the step (d).
- 30. The process of claim 26, wherein the second air velocity is about 0.5 meters per second during a first portion of the second period, and the second air velocity is increased to up to about 13 meters per second during a second portion of the second period in the step (d).
- 31. The process of claim 30, wherein a first dwell time in the first portion of the second period and a second dwell time in the second portion of the second period are approximately equal in the step (d).
- 32. The process of claim 30, wherein the second air velocity is increased to up to about 13 meters per second during the second portion of the second period at a curvilinear rate in the step (d).
- 33. The process according to claim 26 wherein the second period ranges from about 2 minutes to about 20 minutes in the step (d).
- 34. A process for coating a polymeric substrate, comprising the steps of:(a) applying a first powder coating composition to a surface of the polymeric substrate; (b) applying a first infrared radiation at a power density of 30 kilowatts per meter squared or less and optionally a first air simultaneously to the first coating composition for a first period of at least or about 90 seconds, a first temperature of the polymeric substrate being increased at a first rate ranging from about 0.3° C. per second to about 1.25° C. per second to achieve a first peak polymeric temperature ranging from about 125° C. to about 200° C., such that a sintered first coating is formed upon the surface of the polymeric substrate; (c) applying a second powder coating composition over the first coating; and (d) applying a second infrared radiation and a second air simultaneously to the second coating composition for a second period of at least or about 2 minutes, a second temperature of the polymeric substrate being increased at a second rate ranging from about 0.8° C. per second to about 1.3° C. per second to achieve a second peak polymeric temperature of the substrate ranging from about 90° C. to about 175° C., such that a powder layered system is formed upon the surface of the polymeric substrate.
- 35. The process accordingly to claim 34, wherein the first coating composition is a basecoating composition, and the second coating composition is a topcoating composition.
- 36. The process according to claim 34, wherein the first air is applied at a first velocity ranging from about 0.25 meters per second to about 1.0 meters per second in the step (b).
- 37. The process of claim 34, wherein the second air has a second air velocity of about 0.5 meters per second during a first portion of the second period, and the second air velocity is increased to up to about 13 meters per second during a second portion of the second period in the step (d).
- 38. The process according to claim 34, wherein the second air is applied to the second coating composition at a second air velocity ranging from about 0.5 to about 3 meters per second in the step (d).
- 39. The process according to claim 34, further comprising an additional step (b′) of cooling the polymeric substrate having the first coating thereon to a temperature of about 25° C. to about 32° C. between steps (b) and (c).
- 40. The process according to claim 34, wherein the second period ranges from about 2 minutes to about 20 minutes in the step (d).
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 09/840,573, filed Apr. 23, 2001, entitled “Multi-Stage Processes for Coating Substrates with Liquid Basecoat and Powder Topcoat”, which is a continuation-in-part of U.S. patent application Ser. No. 09/320,264, filed May 26, 1999 entitled “Multi-Stage Processes for Coating Substrates with Liquid Basecoat and Powder Topcoat”, now U.S. Pat. No. 6,221,441. This patent application is also related to U.S. patent application Ser. No. 09/320,265 entitled “Multi-Stage Processes for Coating Substrates with Liquid Basecoat and Liquid Topcoat”, now U.S. Pat. No. 6,291,027; U.S. patent application Ser. No. 09/320,483 entitled “Processes for Coating a Metal Substrate with an Electrodeposited Coating Composition and Drying the Same”, now U.S. Pat. No. 6,113,764; U.S. patent application Ser. No. 09/320,484 entitled “Processes For Drying and Curing Primer Coating Compositions”, now U.S. Pat. No. 6,200,650; and U.S. patent application Ser. No. 09/320,522 entitled “Processes For Drying Topcoats And Multicomponent Composite Coatings On Metal And Polymeric Substrates”, now U.S. Pat. No. 6,231,932, all of Donaldson J. Emch. Each of the aforementioned patents and applications are incorporated by reference herein.
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Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
09/840573 |
Apr 2001 |
US |
Child |
09/969480 |
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US |
Parent |
09/320264 |
May 1999 |
US |
Child |
09/840573 |
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US |