A hydrophilic cationic charge modified microporous membrane, a process for producing it and its use.

摘要

A novel cationic charge modified microporous membrane is provided comprising a hydrophilic organic polymeric microporous membrane and a charge modifying amount of a primary cationic charge modifying agent bonded to substantially all of the wetted surfaces of the membrane. The primary charge modifying agent is a water soluble organic polymer having a molecular weight greater than about 1000 wherein each monomer thereof has at least one epoxide group capable of bonding to the surface of the membrane and at least one tertiary amine or quaternary ammonium group. Preferably, a portion of the epoxy groups on the organic polymer are bonded to a secondary charge modifying agent selected from the group consisting of: i) aliphatic amines having at least one primary amine or at least two secondary amines; and ii) aliphatic amines having at least one secondary amine and a carboxyl or hydroxyl substituent. The invention is further directed to a process for cationically charge modifying a hydrophilic organic polymeric microporous membrane by applying to the membrane the aforesaid charge modifying agents, preferably, by contacting the membrane with aqueous solutions of the charge modifying agents. The preferred microporous membrane is nylon, the preferred primary and secondary charge modifying agents are, respectively, polyamido-polyamine epichlorohydrin and tetraethylene pentamine. The invention is further directed to a process for improving the responsiveness of a nylon membrane to charge modification, comprising chemically treating the membrane to provide enhanced ninhydrin response evidencing free amino functionality. The charge modified microporous membrane of this invention may be used for the filtration of fluids, particularly parenteral or biological liquids. The membrane has low extractables and is sanitizable or sterilizable.