초록 ▼

In order to provide a process for curing a coating, in particular a radiation-curable coating, on a work piece, which allows coatings even on difficult to access regions of a three-dimensional work piece to be cured in a simple manner, it is proposed that the work piece is disposed in a plasma gener

In order to provide a process for curing a coating, in particular a radiation-curable coating, on a work piece, which allows coatings even on difficult to access regions of a three-dimensional work piece to be cured in a simple manner, it is proposed that the work piece is disposed in a plasma generation area, and that in the plasma generation area a plasma is generated, by means of which the coating is at least partially cured.

대표청구항 ▼

The invention claimed is: 1. A process for curing a coating on a work piece, comprising: providing a coating on a work piece by one of dip-coating, spray painting, and spraying, said coating comprising a lacquer adapted to be cured by UV radiation, said lacquer containing at least one photo-initiat

The invention claimed is: 1. A process for curing a coating on a work piece, comprising: providing a coating on a work piece by one of dip-coating, spray painting, and spraying, said coating comprising a lacquer adapted to be cured by UV radiation, said lacquer containing at least one photo-initiator; after said providing of said coating on said work piece, placing the work piece with the coating in a plasma generation area; and generating a plasma in said plasma generation area, the UV radiation suitable for curing said coating being generated by stimulating gas particles within said plasma, said gas particles emitting said UV radiation; essentially completely curing said coating by means of said UV radiation emitted by said gas particles and triggering a cross-linking reaction in said coating; wherein: said work piece has a cavity and at least one undercut coated with said coating and/or at least one shaded region coated with said coating, said undercut and said shaded region, respectively, comprising a region into which no UV radiation can reach from the plasma generation area located outside the work piece; and said UV radiation emitted by said gas particles reaches said work piece from different sides thereof and also reaches said undercut and said shaded region, respectively. 2. A process according to claim 1, wherein the UV radiation generated in said plasma has at least one wavelength in the range of approximately 100 nm to approximately 400 nm. 3. A process according to claim 1, wherein the pressure in the plasma generation area is set to a maximum value of approximately 100 Pa. 4. A process according to claim 1, wherein the pressure in the plasma generation area is set to a maximum value of approximately 1 Pa. 5. A process according to claim 1, wherein the pressure in the plasma generation area is set to a maximum value of approximately 0.1 Pa. 6. A process according to claim 1, wherein the plasma generation area contains at least one of: (i) nitrogen, (ii) argon as an inert gas, (iii) another inert gas, as a process gas. 7. A process according to claim 1, wherein the plasma generation area contains a process gas to which at least one of: (i) a metal, (ii) a metal halide, (iii) another additive has been added. 8. A process according to claim 1, wherein the plasma is generated by inputting an electromagnetic radiation into the plasma generation area by means of at least one input device. 9. A process according to claim 8, wherein the plasma is generated by the input of microwave radiation having a frequency in the range of approximately 1 GHz to approximately 10 GHz. 10. A process according to claim 8, wherein the plasma is generated by the input of microwave radiation having a frequency in the range of approximately 2 GHz to approximately 3 GHz. 11. A process according to claim 1, wherein the plasma is generated by inputting electromagnetic radiation into the plasma generation area, said electromagnetic radiation being generated by means of a magnetron. 12. A process according to claim 1, wherein a magnetic field is generated in said plasma generation area to provide an electron cyclotron resonance (ECR) effect. 13. A process according to claim 1, wherein the plasma is generated by inputting an electromagnetic radiation into the plasma generation area by means of a plurality of input devices. 14. A process according to claim 8, wherein: the cavity has an access opening, said coating extending over said work piece and into said cavity, and said electromagnetic radiation input into the plasma generation area by means of at least one input device passes through the access opening into the cavity of the work piece such that said plasma is generated in said cavity and outside of said workpiece for curing the coating. 15. A process according to claim 1, wherein a gas to be ionized is fed to the plasma generation area during the curing process. 16. A process according to claim 15, wherein the gas to be ionized is fed to the plasma generation area by means of a feeder device, which is adjacent to an input device, by means of which an electromagnetic radiation is input into the plasma generation area. 17. A process according to claim 1, wherein the work piece is placed into an antechamber and is transferred from the antechamber into the plasma generation area for the curing process. 18. A process according to claim 17, wherein the antechamber is evacuated after the work piece has been placed therein. 19. A process according to claim 17, wherein the work piece is subjected to microwave radiation in the antechamber in order to provide one of preliminary drying of the coating and ignition of the plasma in the antechamber. 20. A process according to claim 1, wherein the work piece is transferred from the plasma generation area into an exit chamber after the curing process. 21. A process according to claim 20, wherein before the work piece is transferred into the exit chamber, the exit chamber is evacuated. 22. A process according to claim 1, wherein the work piece is non-planar in construction. 23. A process according to claim 1, wherein the work piece comprises an electrically conductive material. 24. A process according to claim 1, wherein the work piece comprises a metallic material. 25. A process according to claim 1, wherein the work piece comprises at least one of a plastic material and wood. 26. A process according to claim 1, wherein the plasma generation area contains at least one of nitrogen, helium and argon as a process gas. 27. A process according to claim 1, wherein the plasma generation area contains a process gas, the composition of which varies during the curing process. 28. A process according to claim 27, wherein the composition of the process gas varies such that during a first phase of the curing process the UV radiation generated in the plasma during the curing process has a first average wavelength, and during a later, second phase of the curing process has a second average wavelength, the second average wavelength being different from the first average wavelength. 29. A process according to claim 28, wherein the second wavelength is less than the first wavelength. 30. A process according to claim 27, wherein the composition of the process gas is varied such that the UV radiation generated in the plasma during the curing process shifts towards lower average wavelengths as the curing duration increases. 31. A process according to claim 1, wherein the plasma is ignited, and at the time at which the plasma is ignited, the plasma generation area contains argon. 32. A process according to claim 31, wherein the plasma generation area contains essentially argon only, at the time at which the plasma is ignited. 33. A process according to claim 1, wherein at least one of a single gas and a mixture of different gases is fed to the plasma generation area via at least one feeder device. 34. A process according to claim 1, wherein the plasma is generated by the input of electromagnetic radiation into the plasma generation area by means of a plurality of input devices, wherein at least two of the input devices have different input powers from one another. 35. A process according to claim 1, wherein the plasma is generated by the input of electromagnetic radiation into the plasma generation area by means of a plurality of input devices, wherein at least two of the input devices differ in design. 36. A process according to claim 1, wherein at least one reflector is provided in the plasma generation area to reflect the UV radiation generated in the plasma. 37. A process according to claim 36, wherein at least one mirror film is provided as a reflector in the plasma generation area. 38. A process according to claim 36, wherein at least a sub-region of boundary walls of the plasma generation area is configured as a reflector. 39. A process according to claim 36, wherein the at least one reflector comprises at least one of aluminium and stainless steel as a reflective material. 40. A process according to claim 36, wherein the at least one reflector is removable from the plasma generation area. 41. A process according to claim 1, wherein gas is drawn off from the plasma generation area via one or more suction devices. 42. A process according to claim 1, wherein pressure in the plasma generation area is varied by means of at least one suction device with a throttle valve. 43. A process according to claim 1, wherein the work piece is electrically separated from boundary walls of the plasma generation area by means of an at least partially electrically insulating holder. 44. A process according to claim 1, wherein the work piece is connected to a different electric potential from an electric potential of boundary walls of the plasma generation area. 45. A process according to claim 1, wherein the work piece is connected in an electrically conductive manner to boundary walls of the plasma generation area by means of an electrically conductive holder. 46. A process according to claim 1, wherein the work piece is connected to the same electric potential as boundary walls of the plasma generation area. 47. A process according to claim 1, wherein the work piece is connected to ground. 48. A process according to claim 1, wherein the work piece is provided with a coating that is curable by a combination of: (i) said UV radiation, and (ii) heat. 49. A process according to claim 1, wherein: the work piece is subjected to additional radiation before, during and/or after generation of the plasma, and said additional radiation is not generated in the plasma. 50. A process according to claim 49, wherein the work piece is subjected to at least one of microwave radiation and infrared radiation, which is not generated in the plasma, before, during and/or after generation of the plasma. 51. A process according to claim 1, wherein the work piece is dried before, after and/or during generation of the plasma. 52. A process according to claim 1, wherein before generation of the plasma, the work piece is subjected to a pressure below atmospheric pressure. 53. A process according to claim 52, wherein said pressure is in the range of approximately 2000 Pa to approximately 50,000 Pa. 54. A process according to claim 1, wherein before generation of the plasma, the work piece is subjected to a pressure below atmospheric pressure, which is higher than the pressure to which the work piece is subjected during generation of the plasma. 55. A process according to claim 1, wherein a magnetic field is generated in the plasma generation area. 56. A process according to claim 55, wherein the intensity of the magnetic field is varied during a curing process. 57. A process according to claim 55, wherein the magnetic field is generated in the plasma generation area only after the start of a curing process. 58. A process according to claim 55, wherein the intensity of the magnetic field varies spatially in the plasma generation area. 59. A process according to claim 1, wherein said work piece is a vehicle body. 60. A process according to claim 1, wherein: the plasma generation area is arranged in a plasma chamber having at least one gate; the work piece is transported into the plasma chamber through the gate by means of a conveyor after said gate is opened; and the plasma is generated after said gate is closed. 61. A process according to claim 1, wherein said lacquer is a dual-cure lacquer which is adapted to be cured by the UV radiation and heat.