Process for making membranes M comprising the following steps: a) providing a dope solution D comprising at least one polymer P and at least one solvent S, b) adding at least one coagulant C to said dope solution D to coagulate said at least one polymer P from said dope solution D to obtain a membrane M, wherein said at least one solvent S comprises more than 50% by weight of at least one compound according to formula (I) (I), wherein R1 and R2 are independently C1 to C20 alkyl, R3 is selected from H or an aliphatic rest, 20 R4 is selected from H or an aliphatic rest, AO represents at least one alkylene oxide, n is a number from 0 to 100.