Patent ID: 9188386
Filing Date: 2015-11-17
Classification: B05D,B28B,C09D,F26B

Abstract:
1. A method of drying a coating film formed on a surface of a PET film, comprising: radiating in a drying furnace an infrared ray having a dominant wavelength of 3.5 μm or less from an infrared heater onto a PET film on whose surface the coating film containing water or an organic solvent having an absorption spectrum of 3.5 μm or less has been formed, where the infrared heater has a structure such that an outer circumference of a filament is covered with a protection tube, and a partition wall for forming a flow passageway of a cooling fluid that restrains rise in temperature of a heater surface is provided in a space surrounding this protection tube, and bringing a cooling air into contact with the surface of the PET film on which the coating film has been formed while applying a tension of around 20-50 N to the PET film, so as to dry the PET film at a temperature lower than a glass transition point of the PET film, wherein a temperature of the coating film and a temperature of the PET film are both maintained at a temperature lower than a glass transition temperature of the PET film at all times during the drying of the coating film, wherein the infrared heater has a structure such that the outer circumference of the filament is covered with a plurality of tubes that absorb an infrared ray having a wavelength in excess of 3.5 μm, and the flow passageway of the cooling fluid that restrains a rise in temperature of the heater surface is formed between the plurality of tubes, and wherein each end of the filament is held by a holder positioned within the flow passageway, and a fluid discharge outlet is positioned inward from one of the holders of the filament so that the fluid supplied into the flow passageway of the cooling fluid is discharged outside of the drying furnace.