Method of preparing a microporous film, and imaging method

摘要

A method for manufacturing a microporous film comprising the steps of:(a) providing a first polymer which is a hydrophobic thermoplastic polymer and a second polymer which is a hydrophilic polymer or copolymer of N-vinylpyrrolidone;(b) dissolving said first and second polymers in a solvent system which is compatible with both polymers, said solvent system comprising a blend of an aprotic organic solvent and an alcohol;(c) coating the resulting solution on a support;(d) effecting at least a partial drying of the resulting coating; and(e) washing the coating in an aqueous medium so as to extract at least 50% by weight of the said second polymer.