| 摘要 |
PURPOSE:To manufacture a flexible printed board lessened in warpage and torsion by a method wherein a polyimide film is set free from distortion after it is cured or burned. CONSTITUTION:Polyamide acid or polyamide organic solvent solution is applied direct onto a metal foil and dried out by heating, and then the metal foil is hardened or burned. The vapor of organic solvent is absorbed in the surface of a coating film while it is dried up. At least three or more hot-air drying chambers 5, 6, 7, and 8 which are separately controllable in temperature and continuously installed and a transfer device which continuously transfers a drying object 12 through the drying chambers 5, 6, 7, and 8 are provided, a duct 11 is installed for guiding organic solvent vapor generated in the fore chambers to the hind chambers, and the drying chamber 8 is set lower than the drying chamber 5 in temperature. |
