The effect of solvent evaporation rate in coating formulation

Bp( ℃)

Relative volatilization rate

N-butanol

118

0.
36

N-butyl acetate

125

1.
0

Bp( ℃)

Relative volatilization rate

Bp( ℃)

Bp( ℃)

Relative volatilization rate

Relative volatilization rate

N-butanol

118

0.
36

N-butanol

N-butanol

118

118

0.
36

0.
36

N-butyl acetate

125

1.
0

N-butyl acetate

N-butyl acetate

125

125

1.
0

1.
0

(2) Relative evaporation rate

That is, select a certain solvent as the standard (usually choose n-butyl acetate, but also use ether), and set its evaporation rate as 1.
The relative evaporation rate of the solvent is defined as: t90 refers to the time required to evaporate 90% of the solvent under the specified conditions.
The reason why the time required to evaporate 90% of the total solvent is used is to avoid errors caused by the interaction between the solvent and the substrate during the evaporation process.

For example: the solvent of epoxy resin is generally 70% xylene + 30% n-butanol

bp( ℃)

Relative volatilization rate

Toluene

111

1.
95

Xylene

135

0.
68

N-butanol

117.
1

0.
45

Isopropanol

82.
5

2.
05

bp( ℃)

Relative volatilization rate

bp( ℃)

bp( ℃)

Relative volatilization rate

Relative volatilization rate

Toluene

111

1.
95

Toluene

Toluene

111

111

1.
95

1.
95

Xylene

135

0.
68

Xylene

Xylene

135

135

0.
68

0.
68

N-butanol

117.
1

0.
45

N-butanol

N-butanol

117.
1

117.
1

0.
45

0.
45

Isopropanol

82.
5

2.
05

Isopropanol

Isopropanol

82.
5

82.
5

2.
05

2.
05

When preparing a mixed solvent, it is hoped that the relative volatilization rate of each component should be kept corresponding to the solvent composition.
If the solvent component with strong dissolving ability volatilizes faster than other components, the resin may be precipitated in the later stage of drying and particles will be generated on the surface of the coating film.
(Source: Global Coatings Network) (For more information, please log in: Global Coatings Network http:// class="info_page">