Preparation And Properties Of Fine-Denier Spandex Air-Covered Yarns And Fabrics

Spandex air-covered yarn is a kind of composite elastic yarn with good elasticity and fluffiness,which is widely used in many kinds of elastic fabrics.The development of fine denier spandex air-covered yarn and its lightweight stretch fabric responds to the increasing demand for lightweight stretch fabrics in recent years.At present,during the production and application of spandex air-covered yarn,the problems of the exposure of core fiber and the shrinkage of fabric size have not been solved effectively.This phenomenon may lead to the instability of production quality.In order to develop high-quality fine-denier spandex air-covered yarn and its fabric products,this project selects low-denier spandex monofilaments which are 10D,20D,and 35D.And then,spinning spandex air-covered yarn products by using them as the core fiber.At the same time,different production parameters are set in the production process.In these ways,we intend to search for the optimal conditions which are good for the structure and performance of spandex air-covered yarn.Then,compare the performance of fabrics with different weft yarns and different fabric tissues.All of these are for reference and guidance for the development of fine-denier spandex air-covered yarns and their light stretch fabrics The main research contents and conclusions of the project are as follows:(1)Performance testing and analysis of spandex monofilaments:Before the heat shrinkage test,the breaking strength,breaking elongation,and elastic recovery rate of 10D spandex were poor compared with the remaining two fineness of spandex;the boiling water shrinkage rate of the three spandex fibers decreased with the increase of spandex yarn fineness.After the boiling water shrinkage test,the macromolecular structure of the three fineness spandex monofilaments did not change,but all the properties of the spandex changed.The specific performance is the increase of spandex yarn breaking strength and elongation,and the decrease of elastic recovery rate,in which the spandex with the fineness of 10D had the most obvious change.The spandex yarn performance prediction which can provide the basis for the subsequent analysis of spandex air-covered yarn and covered-yarn fabric performance.(2)Study and optimization of spandex air-covered yarn production process:The three parameters of spandex core yarn fineness,spandex draw ratio,and processing D/Y ratio were mainly set for single-factor process experiments.In this way,we can investigate the influence of appearance,fluffiness,network,and network fastness,tensile properties,elastic properties,and heat shrinkage of spandex air-covered yarn under these different process parameters.It was found that the strength and elasticity of spandex yarn increased by increasing the draft multiplier,but the elasticity and covering effect of the yarn decreased by too much.When the D/Y ratio of the outer covering yarn was 1.7,the structure uniformity of the covering yarn was the best and the properties were good,so it was determined as the best condition.The spandex core yarn fineness has a great influence on the structure and performance of spandex air-covered yarn.Decreasing the spandex core yarn fineness is beneficial to improve the structural uniformity,network knot fastness,and yarn breaking strength,but the yarn breaking elongation and elastic elongation decrease and yarn thermal shrinkage increase,which may affect the elasticity and dimensional stability of the subsequent fabric products.(3)Preparation and comparative performance analysis of spandex air-covered yarn fabrics:We weave fabrics on the air jet loom by using combed cotton as warp yarn,and spandex air-covered yarn as weft yarn.And then testing fabric performance after the fabric desizing treatment.The results show that:enzyme desizing treatment has less damage to the spandex air-covered yarns,and the fine-denier spandex air-covered yarn fabrics have better elasticity after desizing treatment.Also,the temperature and the processing energy consumption of enzyme desizing treatment are low,so it can be used as the desizing method for fine-denier air-covered yarn fabrics.The weft performance of the fabrics is closely related to the fineness of the spandex core yarn.As the fineness of the spandex core yarn decreases,the weft tensile properties change in the same pattern as the tensile properties of the covered yarn used.But the weft elongation and dimensional change of the fabric have a large reduction.It shows that the covered yarn fabrics with finer spandex core yarn have higher dimensional stability in processing and less weft shrinkage in production.But at the same time,the elastic elongation of the fabric becomes smaller,it will be somewhat limited in the application of high-stretch fabrics.When using (3 1)/(1 1) standard cavalry twill organization,the fabric has good elastic elongation and strength,and can be designed to obtain a lighter and thinner fabric,which can be preferred in the development of light elastic fabrics.Finally,this project found that the finer the fineness of the spandex,the lighter and thinner the (3 1)/(1 1) variation twill fabrics.Also,the air permeability,softness and drapery,and the resistance to fuzziness and pilling are better,which meet the development requirements of thin elastic fabric.