| 摘要 |
PURPOSE: To provide a method for stably producing an excellent phase difference film capable of drastically improving coloring and contrast in the case of observing a quick responsible STN-LCD from the front, in a large amount with high productivity. CONSTITUTION: The polysulfone-based phase difference film is produced by casting a solution, which is obtained by dissolving a polysulfone-based polymer in an organic solvent in a specific concn., stirring at <=5×10<4> dyn/cm<2> shearing stress at the dissolution and filtering the precipitate after allowing to stand for a fixed time, or a solution, which is obtained by concentrating the solution after filtering and before casting, controlling the shearing stress at the time of feeding in and after the concentration to <=5×10<4> dyn/cm<2> and is in <=10hrs after the concentration, and flow drying to obtain a film and further stretching to give birefringence.
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