| US 7,526,878 B2 | ||
| Method and apparatus for drying coating film and method for producing optical film | ||
| Masaki Sonobe, Odawara (Japan); and Takashi Yahiro, Minami-Ashigara (Japan) | ||
| Assigned to FUJIFILM Corporation, Tokyo (Japan) | ||
| Filed on Sep. 25, 2007, as Appl. No. 11/902,735. | ||
| Claims priority of application No. 2006-259659 (JP), filed on Sep. 25, 2006. | ||
| Prior Publication US 2008/0206455 A1, Aug. 28, 2008 | ||
| Int. Cl. F26B 3/30 (2006.01) | ||
| U.S. Cl. 34—266 [34/463; 34/629; 34/636; 427/162; 359/599; 425/223; 118/719] | 18 Claims |
| 1. 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 TW( ° C.) denotes the surface temperature of the band-shaped flexible substrate; TH( ° C.) denotes the surface temperature of the heater; λ(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); η denotes the efficiency of heat transfer; and
η denotes the Stefan-Boltzmann constant (5.670×10−8 W/m2K4), the ratio of radiant heat transfer represented by QR/(QR+QC) is 0.25 or more and 0.6 or less, wherein QC and QR are represented by the following equations, respectively:
QC=λ/d·(TH−TW)
where QC denotes heat transfer by air, and
QR=ησ{(TH+273)4−(TW+273)4}
where QR denotes heat transfer by radiant.
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