
About the hollow-fiber membrane
In the 1970s, a factory of Mitsubishi Rayon (now Mitsubishi Chemical) that developed fibers for filtering water and blood encountered a problem related to the opaque polypropylene fibers produced. A researcher from this company studied the fibers under a microscope and observed numerous pores on the walls of straw-like hollow fibers. The researcher improved the process, and succeeded in developing polypropylene “hollow-fiber membrane filters.” Since then, hollow-fiber membrane filters have been used in wastewater treatment and medical care. Interestingly, they were used to make the first artificial lung device in 1978.