高温长丝纱

常见纤维,如聚酯(PET)和聚酰胺(PA 66),在200℃以上不能使用,并且在热气体过滤时容易水解。通常要求制备膜结构的纤维具有低蠕变、高强度和易清洁等性能。双组分纤维,如聚醚醚酮(PEEK)和含氟热塑性聚合物[全氟烷氧基聚合物(PFA)、氟化乙烯丙烯共聚物(FEP)及热塑性聚四氟乙烯(mPTFE)]能满足这些要求。因此在纺长丝工艺中要求热塑性聚合物的熔点高于300℃,而传统纺纱设计工艺不适合300℃以上的温度,也没有这种纯聚合物,且在较高的拉伸温度下纺丝油剂还易冒烟。含氟聚合物由于其单体容易形成氢氟酸,要求加工设备采用耐蚀、耐热镍基合金或铬镍铁合金制造,至今可以使用的设备只有纺丝泵。报告对这些问题给予了很大关注,并概述了目前的发展状况。

High temperature filament yarn

Common fibers based on PET orPA 6.6 failat temperatures above 200℃ and are prone to hydrolysis at hot gas filtration, e.g. easy to clean fibers with high strength and low creep are required formembrane architecture.Polymers suchasPEEKand fluorinated thermoplasts (PFA,FEP, mPTFE)may fulfill these requirements, if required as bicomponent fibers.Yet thermoplasts with melting pointabove 300℃ are demanding towards the process of filamentspinning:conventional spinning lines are notdesigned forT> 300℃ ;no cleaning polymer is available atmaterialchange, spin finishes are fuming at the high drawing temperatures.The fluoropolymers are even more straining due to theiraggressive monomers,which build hydrofluoric acid that requires equipment ofHastelloy or Inconel.Only now spin pumps are available.The presentation will enlighten these concems and gives a picture of the currentstate‐of‐the‐art.