Structure And Properties Of NEDDP/PBT Self Crimping Two-component Fiber

Polyester two-component juxtaposed composite elastic filament,due to the potential difference in thermal shrinkage between the two juxtaposed components,will form curl after heat treatment and provide curl elasticity.It is a kind of elastic filament that can replace spandex,is not easy to be eroded by chemicals and has stable elastic properties.In addition,the elastic fiber can be used alone without the help of other fiber materials.At present,there are three kinds of successfully commercialized parallel composite elastic filaments,namely PET/PET,PET/PBT and PET/PTT,which have been applied in all kinds of elastic fabrics.However,these three kinds of elastic filaments contain pet components,which need high-temperature and high-pressure dyeing and high-temperature setting,and are not suitable for high-temperature sensitive textiles such as wool and silk;In view of this phenomenon,this paper innovatively proposes to replace pet components with a new atmospheric dispersion dyeable polyester NEDDP,develop NEDDP/PBT elastic filament,and study its spinning process,structure,properties and crimping mechanism.Firstly,NEDDP / PBT elastic filaments under different spinning conditions were obtained by melt spinning with NEDDP and PBT polymers as two components,and the effects of spinning technology on the structure and properties of filaments were studied.The results show that viscosity difference and component ratio are the main factors affecting the structure and properties of NEDDP / PBT bicomponent fiber.When the viscosity difference between the two components increases,the crimp property of the two-component fiber increases,and the mechanical properties and crystal orientation decrease;The crimp shrinkage of two-component fiber is the largest when the proportion of two single components is equal.The mechanical properties of two-component filaments were improved with the increase of NEDDP component;The crystallinity of each single component decreases with the increase of the content of the component.The drafting ratio,drafting temperature and setting temperature have little effect on the mechanical properties of bicomponent fibers,and are positively correlated with their crystal orientation properties.Secondly,the crystal and orientation structures of each single component fiber and the corresponding single component fiber in the two-component fiber are compared and analyzed.The results showed that the sound velocity orientation factors of NEDDP,NEDDP / PBT and PBT fibers decreased in turn.In the spinning process of two-component fibers,NEDDP component crystallized preferentially and assumed the main spinning tension,and its crystallinity was higher than that of single component fibers,while PBT component was just the opposite.The mechanical properties of NEDDP / PBT bicomponent fiber are close to those of PBT monocomponent fiber with weak properties.Finally,the thermal shrinkage properties of NEDDP/PBT under constant external force and constant strain were studied by TMA and DMA.The results show that under the same conditions,the shrinkage strain and shrinkage stress of PBT one-component fiber,NEDDP/PBT two-component fiber and NEDDP one-component fiber gradually decrease.Therefore,in NEDDP / PBT two-component fiber,PBT component shrinks with NEDDP component,PBT is on the inside and NEDDP is on the outside.From the analysis of the spectrum data measured by DMA,it can be seen that the tangent loss of PBT component is the smallest,the tangent loss of NEDDP is the largest,and the two-component fiber is between them and closer to NEDDP component.