Study Of The Formation And Application Of New-type PET Filament Yarn For Wool-like Fabrics

For the many excellent properties of wool fibers (crimping, luster, felting and etc), wool fabrics have a lot of advantages such as softness, crispness, good elasticity, bulkness, springy, subdued luster and thus favored by persons. However, on the one hand, as a kind of nature fibers, the application of wool fiber is affected and restricted by its yield, price and many other factors. At the same time, wool fabrics could not meet some requirements for apparels, especially the required properties of "machine washable", "wash and wear", "easy care" and etc., so the studies on the making of wool-like fabrics were spread out in the world. Through so many years of development, this research has made a lot of progress and many related products and technologies. The most important breakthrough in the study of wool-like fabrics is the usage of fibers with different heat shrinkage. But there has not a complete pattern of the yarn from the unstable state in the transition period to the stable state in the end fabrics to guide the design and production of the wool-like fabrics formerly, only blended spinning for staple fibers with two different heat shrinkages and finally the simulating effects and wearing characteristics of the fabrics were not so good as expected. On the basis of the summary of the technologies for making wool-like fabrics and the further analysis of the structure and performance of wool fabrics, conclusions are made that the structure characteristics of wool fabrics is the key point for the production of wool-like fabrics, which could be summed up as that the yarns are basically packed together, but there are many spaces between fibers within the yarn. Then, a new principle was put forward for the design of wool-like fabrics. This new principle consists of the combination of multi-dispersibility, multi-different shrinkage, multi-different crimping, wet conductivity, luster, handling and etc to make wool-like fabrics. Guided by this principle, put the multi-different shrinkage as the primary parameter, combined with the parameters of linear density, crimping, modulus, rigidity and etc, for the first time, in this paper, the theoretical model of the heat shrinkage distribution of fibers with different crimping needed to imitate the bulky and husky structure like wool yarn in the different levels of the yarn cross section was deduced to improve the simulating effect and provide scientific foundation for the design and production of wool-like fabrics.To the staple fibers, the combined yarn with multi-differences could be easily and conveniently obtained by blended spinning fibers with different properties in the processing, but to the filaments, besides the complexity of technology, considering on equipment efficiency, cost and etc, the similar method as mixed drawing is not desirable. According to the two-step method as pre-oriented yarn (POY) and downstream processing, compound two kinds of POY with different cross section and different linear density as skin yarn and core yarn in the downstream processing wasdesigned in this paper. Then the probability to make the multi-differences yarn by the die-spinning nozzles with different shape of cross section and different diameters in the same spinneret has been analyzed theoretically, especially the formation of the differences in linear density and heat shrinkage between the monofilaments in the multifilament yarn. For a spinneret, differences in the areas of the nozzles lead to the differences in the velocity and viscous resistance of the melt. The larger the area of the die-spinning nozzle is, the bigger the velocity and discharge capacity and the less resistance. Under the same winding speed, there have an obvious different in effective draw ratio and cool-down rate between the monofils formed by different nozzles. Monofils from the large area die-spinning nozzles have large linear densities and lower degree of orientations. According to the study above, design of the spinneret and the spinning for the POY of the core yarn for the new-type filament yarn for woo...