| 摘要 |
PURPOSE:To prevent the change in extruder rate, air bubbles, die tailings and the like from developing by a method wherein the crystallizing treatment of semicrystalline polyimide pellets is performed by agitating it within the respective temperature and time ranges so as to directly feed the resultant crystallizing-treated polyimide pellets into an extruder from a temperature controlling device. CONSTITUTION:Amorphous polyimide pellets 2, which are charged through a hopper 1, is fed with a feeder 3 to a crystallizing device 9 and, at the same time, heated with a screw 4 up to the predetermined crystallizing treatment temperature. The resultant crystallizing-treated pellets 8 are fed through a pellet delivery port 7 to a pellet temperature controller 10 without being brought into contact with air and, after that, conveyed to an extrusion process without being brought into contact with air. In this case, by heat-treating the polyimide pellets, the crystallinity of which is below 5%, within the temperature domain ranging from the temperature, which is below the maximum crystallizing temperature by 30 deg.C, to the temperature, which is above the maximum crystallizing temperature by 20 deg.C, and the time domain ranging from the maximum isothermal crystallization access time to 500% of the maximum isothermal crystallization access time, the polyimide pellets are pelletized, the crystallinity of which is 5% or more. |
