METHOD FOR THE PLASMA CLEANING OF THE SURFACE OF A MATERIAL COATED WITH AN ORGANIC SUBSTANCE AND THE INSTALLATION FOR CARRYING OUT SAID METHOD

• US 20100139864A1
• Filed: 12/04/2009
• Published: 06/10/2010
• Est. Priority Date: 02/19/2002
• Status: Active Grant

• Current Assignee: Usinor
• Original Assignee: Usinor
• Inventors: SILBERBERG, Eric, Reniers, Francois, Michel, Eric, Buess-Herman, Claudine
• Granted Patent: US 8,877,003 B2
• Time in Patent Office: Days
• US Class Current: 156/345.440
• CPC Class Codes: B08B 7/0035 by radiant energy, e.g. UV, laser, light beam or the like
• CPC Class Codes: C23G 5/00 Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
• CPC Class Codes: H01J 37/32348 Dielectric barrier discharge

Abstract

The invention relates to a method of cleaning the surface of a material that is coated with an organic substance. The inventive method is characterized in that it comprises the following steps, consisting in: introducing the material into a treatment chamber, having a pressure of between 10 mbar and 1 bar therein, which is supplied with a gas stream containing at least 90 volume percent of oxygen; and generating a plasma by passing an electric discharge between the surface of the material and a dielectric-covered electrode in order to break down the organic substance under the action of the free radicals O thus produces. The invention also relates to an installation that is used to carry out said method.

Claims

1-13. -13. (canceled)

14. An installation for carrying out a process for cleaning the surface of a material coated with an organic substance, the process comprises introducing said material into a treatment chamber, having a pressure of between 10 mbar and 1 bar therein, which is supplied with a gas stream containing at least 90% oxygen by volume and generating a plasma by passing an electric discharge between the surface of said material and a dielectric-covered electrode, breaking down said organic substance through the action of the free radicals O. thus produced, where the material is in the form of a running strip and said introducing and generating operations are carried out continuously using installations placed in succession along the path of the running strip, the installation comprising:

at least one module comprising a treatment chamber,

means for setting the pressure inside said chamber to a value between 10 mbar and 1 bar,

means for making said grounded strip run through said chamber,

a series of dielectric-covered electrodes placed so as to face that surface of said strip to be treated, where the electrodes are connected to a sinusoidal high-voltage generator, and

means for supplying said chamber with gas and means for extracting from said chamber the gases resulting from the decomposition of the organic substance coating the strip.

15. The installation as claimed in claim 14, wherein the oxygen and/or ozone molecules that are formed by recombination of the free radicals O. produced in said plasma are re-dissociated.

16. The installation as claimed in claim 14, wherein said re-dissociation is carried out using UV radiation of a suitable wavelength.

17. The installation as claimed in claim 14, wherein the voltage applied to initiate the discharge is sinusoidal and has a frequency of between 10 and 100 kHz.

18. The installation as claimed in claim 14, wherein the energy dissipation in the discharge is less than 40 W/cm² and the voltage applied in order to initiate the discharge is less than 4.4 W.

19. The installation as claimed in claim 14, wherein one of the faces of said strip is treated followed in succession by the other.

20. The installation as claimed in claim 14, wherein said material to be treated is a metallic material.

21. The installation as claimed in claim 20, wherein said metallic material is a carbon steel.

22. The installation as claimed in claim 20, wherein said metallic material is steel.

24. The installation as claimed in claim 14, which comprises a succession of an even number of said modules, through which said strip runs in succession, exposing in turn one of its faces to the electrodes of said modules.

25. The installation as claimed in claim 14, further comprising W emission lamps placed between said electrodes.

26. The installation as claimed in claim 14, wherein the process further comprises removing oil from the surface of metallic materials using the generated plasma.

27. The installation as claimed in claim 16, wherein suitable wavelength is approximately 253 nm.

23. The installation as claimed in 20, wherein the process degreases the surface of metallic materials, and further comprises depositing a coating after said degreasing.