| Electro-deposition coating (EDC) is widely used in the automotive industry. The importance of cathodic EDC is its ability to create an especially corrosion-resistant base coat in a single-layer process. The coating in a direct-current electrical field leads to preferential deposition of coating at corners, edges, and protrusions [W. Collong, M. Osterhold, Y.Voskuhl: Applied Rheology 1996(2) 27]. |
| In the following, the cross-linking kinetics of a EDC is investigated. Using the results of kinetic analysis and of a simulation routine for the temperature field in a drying tunnel - a special module of CADFEM/ANSYS - the distribution of degree of reaction over the whole bodywork is predicted. |
| DSC Measurements |
| Instrument: |
NETZSCH DSC 204 Phoenix® |
| Heating rates/(K/min): |
1, 2, 5, 10, 20 |
| Atmosphere/(ml/min): |
N2; 20 |
| Crucible: |
Aluminum, pierced |
| Sample mass/mg: |
9.9 .. 10.1 |
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| The DSC measurements on freeze-dried paint material show a endothermal melting peak directly transferring into the exothermal cross-linking process. |
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| Comparison of experiments (symbols) and calculations (black solid lines) |
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Temperature distribution at bodywork during the drying process.
time: 20 min |
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Distribution of degree of reaction of electro-deposited paint on a bodywork during the drying process.
time: 20 min |
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| The comparison of the distribution of temperature and degree of reaction shows the correlation: at the hottest places the largest degree of reaction is predicted. But the relation between both is not linear: the cross-linking reaction starts first at temperatures higher than 116 °C. |
Thermokinetics
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