The invention relates to a micro-porous membrane comprising a porous membrane carrier made of a first polymeric material (A) and comprising a second polymeric material (B) intimately divided throughout the porous membrane carrier, wherein the porous membrane carrier comprises a plurality of interconnected polymeric fibers, fibrils, filaments and/or lamellae having a thickness of less than 1 μm, the porous membrane carrier has an interconnected open porous structure formed by the plurality of interconnected polymeric fibers, fibrils, filaments and/or lamellae and a porosity of at least 50%; and the polymeric material (B) comprises a thermoplastic polycondensation polymer and is present in an amount of at most 30 wt. %, relative to the total weight of (A) and (B). The invention also relates to a process for preparing such a micro-porous membrane comprising steps wherein (i) a porous membrane carrier made of a first polymeric material (A) is impregnated with a polymer solution comprising a second polymeric material (B) in a solvent system (X), and (ii) the resulting impregnated membrane carrier is quenched in a non-solvent system (Y), thereby precipitating at least part of the second polymeric material (B).