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AssigneeUbe Industries, Ltd.
InventorsToshimune Yoshinaga, Kenji Fukunaga, Yoji Kase
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A process of producing an asymmetric membrane of multicomponent polyimide. The process includes the steps of (1) preparing a multicomponent polyimide blend solution by mixing a polyimide component A having a number-averaged polymerization index NA and a polyimide component B having a number-averaged polymerization index NB, wherein NA and NB satisfies equation 1: 2.35×NA−2.09<NB<450×NA−1.12 1 (2) subjecting the multicomponent polyimide blend solution to further polymerization and imidation reaction, and (3) causing a phase inversion in the resulting multicomponent polyimide blend solution to form an asymmetric membrane. The polyimide component A is raw materials of polyimide A containing a fluorine atom in the chemical structure thereof and/or a polymerization and imidation reaction product of the raw materials. The polyimide component B is raw materials of polyimide B and/or a polymerization and imidation reaction product of the raw materials.
A process of producing an asymmetric membrane of multi-component polyimide, the process comprising the steps of:
A polyimide asymmetric membrane having a dense layer and a porous layer and comprising multi-component polyimide containing a fluorine-containing polyimide, the ratio of the dense layer's fluorine atom concentration (Φs), measured by X-ray photoelectron spectroscopy (XPS), to the overall average fluorine atom concentration (f) of the membrane, Φs/f ranging from 1.1 to 1.8.
Dependencies are inferred from the claim text.