Hollow fibers production method thereof and their applications particularly in the field of membrane-type separations

摘要

Non symmetrical hollow fibres presenting a relatively dense layer (`skin`) (H) of a very small thickness ( 1 &mgr;m) at their outer periphery, which is bound to a so called `open` structure of which the porosity increases in the direction to the inner face; said porous structure comprises microvoids (1) shaped like elongate fingers open to the inside. The invention also relates to the method for obtaining such a symmetrical hollow fibres by known spinning techniques by dry-wet process, by adding to the solution for spinning the polymer in the solvent at least one particular additive and by adding a particular fluid through the hole of the extruded product. Finally, the invention aims at applying the hollow fibres in question to various fields and particularly in ultra- filtration or micro-filtration, in dialysis, reverse osmosis, in gas permeation or pervaporation or they may also be used as supports for liquid membranes.