Electrolysis: processes – compositions used therein – and methods – Electrolytic coating – Forming nonelectrolytic coating after forming nonmetal...
Patent
1998-12-10
1999-11-02
Raimund, Christopher
Electrolysis: processes, compositions used therein, and methods
Electrolytic coating
Forming nonelectrolytic coating after forming nonmetal...
205149, 205158, 4273884, 4273935, 427409, C23C 2800
Patent
active
059763434
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a process for producing a multilayered lacquering, in particular on metallic substrates, which is particularly suitable for vehicle lacquerings.
BACKGROUND OF THE INVENTION
Modern production line car lacquerings mostly consist of a base lacquer/clear lacquer top coat which is applied to an electrophoretically primed car body which has been provided with a filler layer. The base lacquer and clear lacquer are preferably applied wet-on-wet, i.e. the clear lacquer is applied to the base lacquer after an evaporation time, optionally with heating, and the two are stoved together after the clear lacquer has been applied. EP-A-0 238 037 discloses a process which can be used to reduce the stoved layers in which a filler and a water-based metallic base lacquer are applied by the wet-on-wet process. The examples section reveals that the filler layer is applied with a dry film thickness of 35 .mu.m which is conventional for filler lacquers.
EP-A-0 265 363 discloses providing a previously stoved cataphoretically applied primer with a two-layered base lacquer/clear lacquer top coat using a wet-on-wet process. There is no filler layer. However, there is a problem in that damage due to flying stones on vehicles lacquered by this process is particularly conspicuous since the primer layer is revealed when the impact of a stone dislodges the top coat. Although corrosion protection is still guaranteed, the visual impression cannot be tolerated.
For reasons of rationalisation and in order to save materials, there is a desire to reduce the thickness of the layers in vehicle lacquerings when building up the lacquer, but without producing any substantial losses in overall characteristics.
SUMMARY OF THE INVENTION
The object of the invention is to provide a process for producing multi-coat lacquerings, in particular vehicle lacquerings, with a thinner overall layer structure for the total lacquer application, but with comparable overall properties as compared with the prior art, and which can be performed with the smallest possible number of stoving steps.
Surprisingly, the object is achieved by the process provided by the invention for multi-coat lacquering of a substrate provided with a stoved first electrodeposition lacquer layer, which is characterised in that a second coating layer corresponding to a dry layer thickness of 10 to less than 30 .mu.m consisting of a first water-based, colour and/or effect-providing base lacquering agent which contains one or more polyurethane resins is applied to the first electrodeposition lacquer layer, wherein a third coating layer corresponding to a dry layer thickness of 7 to 15 .mu.m consisting of a second water-based, colour and/or effect-providing base lacquering agent is applied wet-on-wet and a fourth coating layer consisting of a clear lacquer coating agent is applied to the third coating layer without prior stoving and the second, third and fourth coating layers are stoved together, wherein a first water-based base lacquering agent is used which has a higher concentration of polyurethane resin than the second base lacquering agent, with respect to the total weight of the particular water-based base lacquering agent, and wherein the solids content in the first base lacquering agent differs by not more than 20% from the absolute value of the weight of solid resin in the second base lacquering agent.
As a result of the process according to the invention, it is possible to apply a water-based base lacquering agent directly onto a stoved first coating layer built up by electrodeposition and to fire this layer together with the subsequently-applied second water-based base lacquer layer and clear lacquer layer, wherein conventional filler layers or other intermediate layers are not required.
DETAILED DESCRIPTION OF THE INVENTION
Any anodic or cathodic depositable electrodeposition lacquers (EDL) known per se which are not subject to any restrictions, may be used as electrodeposition coating agents for producing the first coating laye
REFERENCES:
Ladstadter, E., "Principles of the `SPLITT` stone chip apparatus. Use in automobile paint systems testing." Farbe Lack 1984, vol. 90 No. 8, pp. 646-653.
Herberts Gesellschaft mit beschrankter Haftung
Raimund Christopher
LandOfFree
Multi-coat painting process does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multi-coat painting process, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi-coat painting process will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2130136