Patent ID: 7351365
Filing Date: 2008-04-01
Classification: B01D,B29C

Abstract:
1. A method for obtaining a polymer film, comprising: providing a film-forming device, comprising: a dope supply device containing a prepared dope; a poor solvent supply device containing a poor solvent; a mixer connected to both the dope supply device and the poor solvent supply device; and a casting die connected to the mixer; preparing a polymer solution by mixing a certain amount of poor solvent from the poor solvent supply device with the prepared dope from the dope supply device in the mixer; delivering the polymer solution from the mixer to the casting die; pressurizing and discharging the polymer solution from the casting die; casting the polymer solution on a support; solidifying the polymer solution to form a film on the support; peeling the film from the support; and drying the film, wherein the poor solvent is mixed with the prepared dope such that the polymer solution has a ratio of dynamic modulus of rigidity to dynamic coefficient of viscosity of 0.1 to 3.0 (1/second) prior to discharging the polymer solution from the casting die.