PURPOSE: To eliminate the condensation of liquid with an odor of solvent and consequently reduce the consumption of energy and the cost of facilities by a method wherein a plurality of sheets of film, which is obtained by flowing polyimide solution or polyamide acid solution over a base plate and drying, are simultaneously heat-treated under the state that predetermined intervals are provided between the sheets of the film.
CONSTITUTION: At least two sheets of dry film are simultaneously charged in a heat treatment furnace in order to heat-treat the film under the state that both edge parts of the respective sheets of the film are held. At this time, the respective sheet of the film are arranged so as to have a gap of at least 5mm therebetween. The gap is necessary to completely remove the solvent evaporated from the film during heat treatment and the moisture developed together with the imide ring closure reaction from the surfaces of the sheets of the film. If the sheets of the film are in contact with each other, the evaporated gas does not fully escape from the surfaces of the sheets of the film and consequently stagnates in highly concentrated state and unfavorably condenses. The effects due to said condensation can completely be removed by providing the gap of 5mm between the respective sheet of the film.
SUGAWARA TAKAO
HASE YASUHIRO
