Study On The Crimp Figure And Elasticity Of The PET/PTT Bicomponent Fiber

In recent years,the situation of the successful commercialization of the PET/PTT fiber and the advantage of the replacement of the spandex attracted many peoples' attention.Now the articles are focus on the mechanism of the self-crimp,the spinning condition,the condition of the crimp take place,and the test of the crimp and so on,but there is no report about the relation of the crimp and elastic properties.And the elastic property is the most attractive property of the PET/PTT fiber.The study of the affection of the crimp on the elasticity,it can be a technique support for a reasonable usage.The works and the conclusions are below:At the first,we test the stress-strain curve,the elongation under certain stress,the recovery of certain elongation and stress decay of the three kinds of elastic fibers------spandex,polyolefin XLA and PET/PTT bicomponent.It can conclude that the Spandex and polyolefin XLA^? has a higher broken elongation and elongation under the stress of 0.25N,so it has to be wrapped in use.Meanwhile,it can slack easily after several times of stretch.The PET/PTT has a bigger strength and the elongation under the stress is enough,so it can use directly without wrapping.And the recovery based on the elongation is higher,the slackness is small,it can be used in all kinds of low and medium elastic fabrics.And then the crimp shape and crimp elasticity characters of the PET/PTT monofilaments and multifilament under different tension and temperature were analyzed.As the tension of the heat treatment rise,the crimp frequency and the crimp radius of the monofilament goes down,so dose the crimp elongation rate,the crimp recovery rate and the crimp modulus of the monofilament and multifilament goes up.As the temperature of the heat treatment rise,the crimp frequency increases and the crimp radius decreases.And the crimp elongation decreases;the crimp recovery rate and the crimp modulus of the monofilament and multifilament increases.When the temperature is 100¹20 and the tension is small,the crimp elasticity of the PET/PTT monofilaments and multifilament are better.And the crimp elasticity of the multifilament has the same trend of the monofilament,and the dispersion of the monofilaments is bigger than the multifilament because the properties of every multifilament are different.And then the elements that affected the elongation of the PET/PTT fiber's elongation were studied.It concluded that the essence of the material,the diameter of the fiber,the crimp frequency and radius affected the crimp elongation rate of the PET/PTT fiber.And the essence of the material has the biggest influence.The initial modulus,the diameter of the fiber,the crimp frequency is inversely proportional to the crimp elongation rate of the multifilament and monofilament,and the radius of the crimp is proportional to the crimp elongation rate of the multifilament and monofilament.And based on the above study,a model between the crimp figure parameter and the crimp elasticity was built to guide the production and some experiments were done to verify it.The predicted value is dovetailed with the measured value,when the relative error of the small crimp elongation rate is bigger than the big crimp elongation rate.The predicted value is bigger than the measured value because the assumed condition is idealized.