Method of coating a substrate

Abstract

A method is provided for coating a substrate, in particular a fiber reinforced plastic component, a protective layer being applied, with preference by means of thermal spraying, to a non-cured resin film applied to a release film, and subsequently, after removal of the release film, the resin film being applied to the substrate and cured.

Claims

1. A method for coating a carbon fiber reinforced plastic component, the method comprising: (a) providing a non-cured resin film, applied to a release film, the non-cured resin being at least one selected from the group consisting of thermoplastic resin, polyurethane resin, polyester resin or epoxy resin; (b) applying at least one protective layer to a side of the non-cured resin film opposite the release film by a thermal spraying method, wherein an adhesive attachment of particles of the at least one protective layer is proportional to an energy that these particles possess and said particles penetrate into the non-cured resin film, so that after completion of the thermal spraying a material of the at least one protective layer achieves an effect of positive anchoring of the material on the non-cured resin film, and wherein the at least one protective layer being formed from at least one material selected from the group consisting of metals, metal alloys, plastics and ceramics, wherein said non-cured resin film is separated from said carbon fiber reinforced plastic component during application of said at least one protective layer; (c) removing the release film from the non-cured resin film to expose a bonding surface of the resin film; (d) applying the non-cured resin film having the at least one protective layer to the carbon fiber reinforced plastic component to be coated via the exposed bonding surface, wherein a final curing of the non-cured resin film is not completed before the non-cured resin film is applied to the carbon fiber reinforced plastic component; and (e) final curing of the non-cured resin film for the adhesive attachment of the completely cured resin film only after application to the carbon fiber reinforced plastic component, wherein the non-cured resin film is brought into a desired form before application of the protective layer, wherein the non-cured resin film protected by means of the release film is placed onto a surface that has a same three-dimensional structure as a structure of the carbon fiber reinforced plastic component.

2. The method according to claim 1, wherein the at least one protective layer is formed from a ceramic, selected from carbides and/or oxides.

3. The method according to claim 1, wherein the at least one protective layer comprises a metal selected from the group consisting of aluminium, zinc, nickel and copper.

4. The method according to claim 1, wherein the at least one protective layer comprises a metal alloy selected from the group consisting of alloys of the metals aluminium, zinc, nickel and/or copper.

5. The method according to claim 1, wherein the non-cured resin film is formed as a two-component epoxy resin.

6. The method according to claim 1, wherein the non-cured resin film is cured over a large area or partially by heating and/or irradiating the same.

7. The method according to claim 1, wherein a surface of the carbon fiber reinforced plastic component to which the non-cured resin film is applied is roughened and/or cleaned before application of the resin film.

8. The method according to claim 1, wherein the release film is formed as a polytetrafluoroethylene film.

9. The method according to claim 1, wherein the non-cured resin film is a polyurethane, polyester or epoxy resin film, and wherein, after the application of the at least one protective layer, the non-cured resin film is stored at a temperature of below 10° C., for a predetermined period of time.

10. The method according to claim 1, wherein after the application of the at least one protective layer, the non-cured resin film is stored at a temperature of below 0° C., for a predetermined period of time.

11. The method according to claim 1, wherein after the application of the at least one protective layer, the non-cured resin film is stored at a temperature of below −15° C., for a predetermined period of time.

12. The method according to claim 1, wherein the resin film is formed as a thermoplastic resin film, and wherein, after application of the at least one protective layer, the thermoplastic resin film is stored at room temperature for a predetermined period of time.

13. The method according to claim 1, wherein the particles of the at least one protective layer thereby penetrates partially into the non-cured resin film in a first method step of the thermal spraying method, in order subsequently to take the form of applied and partially embedded thermally sprayed particles, so that after the application of this first sprayed layer further thermally sprayed layers are applied to the non-cured resin film.

14. The method according to claim 1, wherein the resin film remains in a non-cured state before the resin film is applied to the carbon fiber reinforced plastic component and final curing of the resin film in a cured state is performed after the application to the carbon fiber reinforced plastic component.

15. The method according to claim 1, wherein a surface of the carbon fiber reinforced plastic component to which the non-cured resin film is applied is roughened before application of the non-cured resin film.

16. The method according to claim 1, wherein during the curing of the non-cured resin film, bonds are formed between a surface of the carbon fiber reinforced plastic component and the resin film and wherein the bonds are responsible for the adhesive strength of the cured resin film on the carbon fiber reinforced plastic component and for the adhesive attachment of the protective layer on the carbon fiber reinforced plastic component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying figures, in which:

(2) FIG. 1 shows a cross-sectional view of an arrangement with a release film and a resin applied to it;

(3) FIG. 2 shows the method step of applying coating particles to the resin film from FIG. 1 in a cross-sectional view;

(4) FIG. 3 shows a cross-sectional view of a protective layer applied to a resin film; and

(5) FIG. 4 shows a cross-sectional view of a resin film applied to a substrate and with a protective layer.

(6) Unless otherwise specified, in the figures the same reference numerals designate components that are the same or functionally the same.

DETAILED DESCRIPTION OF THE INVENTION

(7) FIG. 1 shows a cross-sectional view of a resin film 2 applied to a release film 1. The resin film 2 consists, for example, of a two-component epoxy resin. It is preferably a toughened epoxy resin that can be kept at −18° C. for 18 months and at 22° C. for 42 days.

(8) The resin is evenly applied to the release film 1 of Teflon®, in order to form a resin film 2. The release film 1 protects a bonding surface 9 of the resin film 2 before the application of the resin film 2 to a substrate from premature and/or undesired adhesive attachment and/or from contamination of the bonding surface 9.

(9) In a next step, aluminium particles 3 are applied to the resin film 2 by means of thermal spraying, as represented in FIG. 2. The particles 3 thereby penetrate partially into the resin film 2 in a first method step of the thermal spraying, in order subsequently to take the form of applied and partially embedded sprayed particles 4.

(10) After application of this first sprayed layer, further sprayed layers are advantageously applied to the resin film. FIG. 3 shows the resin film 2 on the release film 1 with the embedded particles 4 of the first sprayed layer and further particles 5 and 6 of the second and third sprayed layers. As represented in FIG. 3, the applied particles of the various sprayed layers form a homogeneous protective layer 7 with very good adhesive attachment. The particles are positively anchored. It is obvious to a person skilled in the art that any number of sprayed layers is possible for forming the protective layer.

(11) In a further method step, the release film is removed from the resin film. As a result, the bonding surface 9 of the resin film is exposed. The bonding surface 9 lies here on the side opposite from the protective layer 7. The exposed resin film is applied with the bonding surface 9 to a surface that has previously been roughened by means of very fine emery paper and cleaned, for example a surface of a structural component 8 of an aircraft, such as in particular a leading edge of carbon fiber reinforced plastic on a tail unit. After curing of the resin at 180° C., a coating with excellent adhesive attachment is obtained on the CRP component 8. It is obvious to a person skilled in the relevant art that the temperature necessary for the curing of the resin film must be made to match the nature of the resin. The skilled person therefore chooses a curing temperature that is appropriate for the resin. In the case of resins that are cured by means of irradiation, the skilled person also makes the kind of irradiation match the nature of the resin.

(12) FIG. 4 shows a cross section through the CRP component 8 with a coating 7 applied to it, which is adhesively attached by way of the bonding surface 9 to the CRP component 8 by means of a resin film 2. This coating, for example on a leading edge of a tail unit of an aircraft, serves for lightning protection.

(13) Although the present invention has been described here on the basis of preferred exemplary embodiments, it is not restricted to these but can be modified in various ways.

(14) For example, the sprayed layer applied to the resin film may serve as an adherend surface for further layers. After application of the resin film with the applied coating to a substrate, it can be further coated by means of thermal spraying. The applied resin film and the coating applied on top of it serve in this case as an adherend surface and insulate the substrate lying thereunder. Therefore, strong heating of the substrate during the thermal spraying is prevented. Moreover, the excellent adhesive attachment of the resin film both to the applied coating and to the substrate allows a base to serve as an adherend surface for further layers that can otherwise only be applied with difficulty to the substrate. On account of the good insulating ability of the resin and the already applied protective layer, the further layers can be applied by means of thermal spraying without lengthy waiting times, that is to say without interim cooling down of the substrate. After the curing of the resin film, if need be the applied layer can be re-worked, for example by renewed roughening, before further coating, and/or can be re-worked by polishing after further coating. Re-working of the sprayed layer is also possible without any further subsequent coating.

(15) If a protective layer is to be applied to a component with a curved surface, the resin film may be brought into the desired form before application of the protective layer. This can take place, for example, by placing the resin film, protected by means of a release film, onto a surface that has the same three-dimensional structure as the substrate to be coated. Since the resin film is protected by a release film, the resin film can be removed from the three-dimensional structure after the coating, and a coated resin film that is adapted in its three-dimensional structure to the surface structure of the component to be coated is obtained.