Teijin has developed a new polyester fiber, which is the finest in the world and has a cross section whose diameter is 200nm, equivalent to 1/90,000 of human’s hair. The fibres are anticipated to be used as a filter that removes impurities in a semiconductor manufacturing process where a high purity level is required. In this case, the filter has a filtration efficiency of more than 99.99% and is able to collect impalpable impurities whose length is around 0.3μm. Currently at Teijin, a polypropylene nanofiber is under development. Their aim is to produce a polypropylene nanofiber which has higher chemical resistance than polyester, with a diameter of 200nm. It would achieve a practical level in 2019.

JCFA News Letter (No.15) May, 2018/Japan Chemical Fibers Association