Method for preparing a uniform polyolefinic microporous hollow fiber

摘要

The present invention provides microporous hollow fiber with improved structural and performance characteristics and a process and apparatus for preparing the improved fiber. The microporous hollow fiber possesses substantially uniform wall thickness, cross-sectional dimensions and porosity. Such characteristics are obtained by melt spinning hollow fiber precursor under defined conditions in a substantially vertically upward direction and subjecting the precursor to a symmetrical quenching step which may be achieved using a hollow annular structure surrounding the precursor. The structure, which is connected to a source of gas, has one or more openings on its inner surface that distribute the gas against the precursor in a substantially uniform manner.