Microporous tubes and process for producing the same

Abstract From the Canadian patent

Polytetrafluoroethylene resin tubes having small pore size and a thickness to inside diameter ratio of 0.07 or less and, yet at the same time, having a high porosity are produced by a, process which includes stretching the tubes by drawing using a metal die and a metal plug. By using the die and plug the, stress necessary for stretching is converted to a compressive force in the thickness direction of the tube. This compressive force is an essential factor in producing the microporous structure of the tubes. The tubes provide meaningful materials for artificial tubular internal organs or industrial filtration.