Automotive Coatings Formulation: Chemistry, Physics und Practices

3.7.3.7 Solvents
On account of the solubility of cellulose acetobutyrate and the specific application process (wet-
on-wet application), the solvents in basecoats are different from those in solid colour topcoats. The 
solvent composition contains solvents which have a more polar character and shorter evaporation 
times. The most important solvents here are esters (e.g. butyl acetate), aromatic hydrocarbons 
(e.g. xylene) and alcohols (e.g. butanol). However, to ensure optimum flow and levelling during 
film forming by physical drying, some slow- evaporation solvents, e.g. glycol ethers (e.g. methoxy 
propanol) or glycol ether esters (e.g. methoxy propyl acetate), must be added.
Table 3.7.2: Formulation and characteristics for a metallic basecoat (silver coloured)
Pos.
Components
Solid m
Density g/ml
Formulation wt-%
01
saturated polyester. modified by 
crystalline urea (50 % in aromatic 
100/xylene/methoxy propanol)
19.65
1.2
39.30
02
polyethylene copolymer wax
dispersion (4,7 % in xylene, butyl 
acetate, n-butanol)
0.74
1.0
15.70
03
imino-melamine resin 
(70 % in n-butanol)
7.63
1.5
10.90
04
butyl acetate
1.50
05
aluminium pigment 
(65 % in solvent)
4.81
7.40
06
butyl acetate
5.90
07
xylene
1.50
08
cellulose acetobutyrate 
(25 % in butyl acetate)
4.45
1.2
17.80
sum
37.28
100.00
pos
.
01
Setal 90173, 50 % in aromatic 100/xylene/PM (Nuplex)
02 
Ceratix 8461 (Altana Cera BV)
03 
Setamin US 138 70 % in n-butanol (Nuplex) 
05 
Stapa Metallux R 9755 (Altana Eckardt)
08 
CAB 381-0,5, 25 % in butyl acetate (Eastman Chemicals)
Automotive OEM coatings

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