| 摘要 |
The present invention provides a method for drying a coating film comprising drying a coating film of an organic solvent-containing coating liquid applied to a running band-shaped flexible substrate, the drying method comprising the steps of: providing a heater at a position opposed to the band-shaped flexible substrate at a running position immediately after coating; and heating the band-shaped flexible substrate by the heater; wherein when T<SUB>W </SUB>(° C.) denotes the surface temperature of the band-shaped flexible substrate; T<SUB>H </SUB>(° C.) denotes the surface temperature of the heater; lambda (W/m.K) denotes the heat-transfer coefficient of air; d(m) denotes the distance between the heater and the band-shaped flexible substrate (web); eta denotes the efficiency of heat transfer; and sigma denotes the Stefan-Boltzmann constant (5.670x10<SUP>-8 </SUP>W/m<SUP>2</SUP>K<SUP>4</SUP>), the ratio of radiant heat transfer represented by Q<SUB>R</SUB>/(Q<SUB>R</SUB>+Q<SUB>C</SUB>) is 0.25 or more and 0.6 or less, wherein Q<SUB>C </SUB>and Q<SUB>R </SUB>are represented by the following equations, respectively: Q<SUB>C</SUB>=lambda/d.(T<SUB>H</SUB>-T<SUB>W</SUB>) where Q<SUB>C </SUB>denotes heat transfer by air, and Q<SUB>R</SUB>=eta{(T<SUB>H</SUB>+273)<SUP>4</SUP>-(T<SUB>w</SUB>+273)<SUP>4</SUP>} where Q<SUB>R </SUB>denotes heat transfer by radiant.
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