Novel Technology to Evaluate Misting in High Speed Film Coating, 2001 Coating Conference Proceedings

Koji Okomori, Hideki Hayasaka, Hirokazu Morii and Hideki Fujiwara--A new evaluation method and system were suggested to determine the quantity of misting in high-speed film coating. The amount of coating mist in the pressure nip outlet was described by the unit "mm / hour," the same as the rainfall unit. Amounts of coating mist were gathered in a vessel containing water for 30 seconds in the center of the web and at a distance of 450 mm from the nip. Light absorbency of a suspension of coating and water was measured by a spectrophotometer, and the amount of misting was calculated. Results showed amounts of misting increased with increasing machine speed and/or water retention, which is well known. These results suggested this new evaluation method and system were useful to determine the amount of misting in high-speed film coating. The new evaluation method and system can also be applied to measuring the amount of starch misting on a non-pigmented size press.