There is no international consensus. The US PET Neighborhood Committee defines fibers with a monofilament fineness of 0.3~1.0 dtex as superfine fibers, Japan defines fibers with a monofilament fineness below 0.55 dtex as ultrafine fibers, and Italy defines monofilaments as monofilaments. Fibers with a fineness of 0.5 dtex or less are defined as ultra-fine fibers, but most people think that those with a monofilament fineness less than 1 dtex are ultra-fine fibers, and those with a single filament fineness of less than 0.1 dtex are considered ultra-fine fibers. my country’s textile industry believes that fibers with a monofilament fineness less than 0.44 dtex are defined as ultrafine fibers. Most synthetic fibers can be prepared into ultrafine fibers, such as polyamide, polyester, polypropylene, polyacrylonitrile and other fibers.
