PTFE HOLLOW FIBER MEMBRANE HAVING POROSITY

摘要

PURPOSE: Provided is a porous PTFE hollow fiber separating membrane capable of remarkably improving filterability and performing a precise filtration process wherein fluid passing through from the inside of the hollow fiber to the outside. CONSTITUTION: A porous PTFE hollow fiber separating membrane comprises a node and a fibril, and the density of the porous PTFE hollow fiber decreases from the inside of the porous PTFE hollow fiber to the outside. Porosity increases from the inside to the outside. The length of the fibril increases from the inside to the outside. The size of an opening increases from the inside to the outside. [Reference numerals] (S1) Step of producing paste by mixing polytetrafluoroethylene (PTFE) powder and liquid lubricant; (S2) Step of extruding the paste in an extruder to preliminarily mold in a hollow fiber form; (S3) Step of injecting gas of low temperature inside the preliminarily mold hollow fiber and extruding in the extruder; (S4) Step of heating the extruded hollow fiber to remove liquid lubricant; (S5) Step of extending hollow fiber in which liquid lubricant is removed to form pores in hollow fiber; (S6) Step of plasticizing the extended hollow fiber