Multi-layer microfiltration membrane having an integrated prefiltration layer and method of making same

摘要

A multi-layer microfiltration membrane having an integrated prefiltration layer. Pursuant to a phase inversion process, several layers are successively poured out onto one another prior to phase separation of a lower layer, with the viscosity for the pour solution decreasing toward the upper layers. This produces a microporous, multi-layer, integral filtration membrane having a homogenous symmetrical pore structure for the final filtration layer and an open-pored structure for the prefiltration layer disposed therebelow. Even with small pore diameters, this membrane can be easily pleated for installation in filter cartridges without the formation of damage at the crease edges. High throughput rates are possible at a low tendency to clog.