Method for producing color and/or effect-producing multilayer paints on car bodies
Disclosed is a process for producing multicoat color and/or effect paint systems on automobile bodies. The disclosed process includes applying an aqueous base coat material to the body and drying or partially curing the resultant aqueous basecoat film, applying an aqueous powder slurry clearcoat material to the dried or partially cured aqueous basecoat film (I), and curing the films (I) and (II) by heat or by heat and actinic radiation (dual cure). Applying the aqueous powder slurry clearcoat material (II) involves electrostatic coating of the exterior body parts, followed by pneumatic spraying (compressed air spraying) of the interior body parts.
1. A process for producing multicoat paint system on an automobile body comprising exterior and interior body parts, the process comprising
applying an aqueous base coat material to the body to provide a basecoat film (I),
applying an aqueous powder slurry clearcoat material to the basecoat film (I) to provide a clearcoat film (II), and
curing the films (I) and (II) by a curing mechanism comprising heat,
wherein applying the aqueous powder slurry clearcoat material (II) comprises electrostatically coating exterior body parts, followed by pneumatic spraying of interior body parts.
2. The process of claim 1 , wherein electrostatic coating is carried out by means selected from the group consisting of an electrostatic spraying slot, an electrostatic spraying bell and an electrostatic spraying disk.
3. The process of claim 1 , wherein electrostatic coating is carried out by means of electrostatically assisted mechanical atomization.
4. The process of claim 3 , wherein electrostatically assisted mechanical atomization uses at least one of electrostatic high-speed rotating disks or high-speed rotating bells.
5. The process of claim 1 , wherein prior to the application of the aqueous basecoat material a surfacer is applied to the body.
6. The process of claim 5 , wherein an aqueous surfacer is used.
7. The process of claim 1 , wherein a polyurethane-based aqueous basecoat material is used.
8. The process of claim 5 , wherein the body is coated with a carthodically deposited electrocoat material before the application of the surfacer and is then baked together with the surfacer film.
9. The process of claim 1 further comprising drying the basecoat film (I) before the aqueous powder slurry clearcoat material is applied.
10. The process of claim 9 further comprising partially curing the aqueous basecoat film (I) before the aqueous powder slurry clearcoat material is applied.
11. The process of claim 1 wherein the curing mechanism further comprises actinic radiation.
12. The process of claim 5 , wherein the applied surfacer is dried prior to the application of the aqueous basecoat material.
13. The process of claim 12 , wherein the applied surfacer is partially cured prior to the application of the aqueous basecoat material.
14. The process of claim 13 , wherein the applied surfacer is cured prior to the application of the aqueous basecoat material.
15. The process of claim 8 , wherein the cathodically deposited electrocoat material is dried before the application of the surfacer.
16. The process of claim 15 , wherein the cathodically deposited electrocoat material is partially thermally cured before the application of the surfacer.
17. The process of claim 16 , wherein the cathodically deposited electrocoat material is thermally cured before the application of the surfacer.
18. A process for producing multicoat paint system on an automobile body comprising exterior and interior body parts, the process comprising
applying a polyurethane-based aqueous base coat material (I) to the body to provide a basecoat film (I),
applying an aqueous powder slurry clearcoat material (II) to the basecoat film (I) to provide a clearcoat film (II), and
curing the films (I) and (II) by a curing mechanism comprising heat,
wherein applying the aqueous powder slurry clearcoat material (II) comprises electrostatically coating exterior body parts, followed by pneumatic spraying of interior body parts,
wherein wet powder slurry clearcoat film, present on the outside of the automobile body and applied by electrostatic coating are able to take up spray mist drops from the pneumatic spraying of interior coating, wherein greater leveling is obtained according to a comparison to pneumatic spraying of interior body parts followed by electrostatically coating exterior body parts, as measured by wavescan.
19. The process of claim 18 , wherein the longwave waviness is reduced according to the comparison.
20. The process of claim 18 , wherein the shortwave waviness and the haze are reduced according to the comparison.