PURPOSE: To efficiently separate an arom. substance from a non-aromatic substance by successively laminating three layers consisting of a thin dense layer, open cellular structural body and thin non-continuous film, thereby forming an anisotropic arom. polyurea/urethane membrane.
CONSTITUTION: A casting soln. is prepd. by dissolving a polyurea/urethane copolymer into a good solvent contg. about <5 vol.% non-solvent. The membrane of the casting soln. is adhered onto a support substrate having the max. pore diameter below 20 μm. This membrane is then treated under conditions of about ≤1000 mmHg-min in a solvent vapor pressure-time factor of ≤1000 mmHg-min. The resulted membrane is cooled in a medium for non- solvent cooling to form the anisotropic polyurea/urethane membrane. This membrane has the three-layered structure consisting of the thin dense layer, the open cellular structural body and the thin non-continuous film.
BAANDO ARUFURETSUDO KOONITSUTS
ROBAATO CHIYAARUZU SHIYUTSUKAA
