| 摘要 |
PURPOSE: To lower a surface energy by casting a polymer solution on a surface of a support, drying the polymer, and releasing the generated self-supporting film from the surface of the support. CONSTITUTION: The process for producing a low birefringent self-supporting polymer films comprises the steps of preparing a polymer solution, casting the solution on a support, drying the polymer, and releasing the generated self-supporting film from the support. In this case, the support is improved to have a low surface energy surface. The surface energy of the support on which the solution is cast is less than about 35 dyne/cm. If the film is cast on a surface having a low surface energy, a birefringence of the self-supporting film is lowered. As the polymer used, a bisphenol A polycarbonate, a tetramethyl-bisphenol A polycarbonate, a polystyrene or the like is used. A solvent used to form the solution is selected not to dissolve a substance for constituting the surface of the support for casting the solution. Thus, the low birefringent film can be formed without necessity of a solvent dipping or heat treating. |
