Asymmetric, permanently hydrophilic filtration membranes

Asymmetric microfiltration and loose ultrafiltration membranes with permanent hydrophilic groups in the matrix are described. The membranes are internally hydrophilic and non-leachable. The membranes are prepared from a casting solution containing polysulfone and an additional hydrophilic polymer component, such as polyvinylpyrrolidone, which imparts an interpenetrating, permanent hydrophilic group to the membrane. The membranes combine high water flow rates with integrity testability by conventional diffusion methods.