Automotive Coatings Formulation: Chemistry, Physics und Practices

2.1.4 Additives
Additives in coatings are used under the aspect “a little goes a long way”. Additives sometimes 
constitute less than 1 % of the paint formulation. Some facilitate paint manufacture; others 
enhance the application properties of the liquid paint. Finally, there are additives which unfold 
their effects in the finished coating films. Additives are ranked mostly by their effects and then 
by their chemical composition. A widely known raw materials list for coating systems 
[24]
lists 34 
groups of additives. The following list here contains those additive groups which are important 
for automotive paints:
• 
wetting agents for substrates and pigments
• 
rheology agents
• 
catalysts for crosslinking reactions and initiators
• 
levelling agents
• 
light stabilisers
The composition and properties of the various additives are described in the chapters on the 
various paint systems.
Water
n-Butanol
Butyl 
glycol
m-Xylene
Benzine 
100/140
Aromatic 
150
boiling temperatures
(°C, 1013 hPa)
100
116–118
167–173
136–139
110–140
177–206
evaporation rate
(diethylether=1)
80
33
160
13.5
7.6
115
evaporation enthalpy
(kJ/kg on bp)
2.258
599
368
344
322
305
density (g/ml)
1.00
0.81
0.90
0.86
0.74
0.89
surface tension 
(mN/m, 20°C)
72.2
25.5
27.8
29.5
25.2
33.7
conductivity (kW/cm)
10
50
100
>10
6
>10
6
>10
6
amount of carbon (mg/g)
0
648
610
906
842
900
Table 2.3: Physical constants of water in comparison to other solvents
General aspects of coatings

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