Effect Of Heat Setting On Mechanical Properties Of Elastic Fabrics

As fabrics are increasingly used in smart wearable,medical monitoring,military and other fields,it is increasingly important to have good mechanical properties.Elastic fabric is popular with the public because of its elasticity and softness and has broad application prospects in real life.Heat setting is a technological process to improve the quality of thermoplastic fibers and textiles,in which temperature,time and tension of heat setting are the main parameters that affect the shaping effect of fabrics,while basic parameters and mechanical properties of fabrics are important indexes to evaluate fabrics.Currently,scholars usually only discuss the influence of heat setting on a single performance of a certain yarn or fabric.There is a lack of systematic research on the mechanical properties of elastic fabrics.Therefore,this topic intends to change the structure of fabric raw materials by heat setting.By changing various parameters of heat setting process,the influence of heat setting on mechanical properties of elastic fabric is systematically discussed,and the parameters of heat setting process are optimized.Specific research contents and conclusions are as follows:The first part mainly focuses on the selection of inelastic yarn and knitted fabric structure,the preparation of knitted fabric containing inelastic yarn,heat setting experiment and performance characterization,and the optimization of technological parameters by orthogonal experiment.Firstly,polyester yarn is selected as the raw material according to the characteristics of yarn,and four-flat stitch fabric is selected as the fabric structure according to the characteristics of four-flat stitch fabric.Secondly,the sample of polyester Siping knitted fabric was prepared by knitting technology,and the DSC curve of the selected yarn was determined by differential scanning calorimetry(DSC for short),and the temperature and time range of heat setting were preliminatively determined according to the DSC curve and previous literature.After the sample was processed by heat setting,the performance test was carried out,including the basic parameters,flexural stiffness,wrinkle resistance and elasticity test.Finally,the optimal temperature for the comprehensive performance of polyester Siping knitted fabric was determined to be 200℃,and the heat setting time was 30 s.The sample will be tension heat setting(the size of the tension in this topic is expressed by the elongation of the fabric),and finally determined that when the lateral elongation of 10% is applied to the fabric,the comprehensive performance of the fabric is the best.The optimum heat setting parameters of polyester Siflat knitted fabric were determined by orthogonal experiment as follows: applying 10% transverse elongation,210℃ heat setting temperature and 45 s heat setting time,the flexural rigidity of the fabric was 0.32 m N ·cm(transverse)and 1.94 m N ·cm(longitudinal),respectively.The transverse elastic response rates were 70.46%.The lateral hysteresis rate was 53.20%.In order to further improve the elastic properties of fabric,elastic yarn is selected as the raw material of yarn in the next chapter.The second part mainly focuses on the selection of elastic yarn,the preparation of knitted fabric containing elastic yarn,heat setting experiment and performance characterization,and the optimization of technological parameters by orthogonal experiment.Firstly,the spandex coated yarn is selected as the raw material according to the yarn characteristics,and the same fabric as the first part is selected as the knitted fabric structure.Secondly,the sample of spandex Siping knitted fabric was prepared and the DSC curve of the selected yarn was determined to determine the temperature and time range of heat setting.After the sample was treated by heat setting,the performance test was carried out to determine that the optimal temperature of the spandex knitwear was 160℃ and the time of heat setting was 30 s.Tensile heat setting was carried out in the experiment,and the properties of the sample were tested after treatment.Finally,it was determined that when10% transverse elongation was applied to the fabric,the comprehensive properties of the fabric were optimal.The optimal heat setting parameters of spandex Siflat knitted fabric were determined by orthogonal experiment as follows: applying 10% transverse elongation,150℃ heat setting temperature and 45 s heat setting time,the flexural rigidity of the fabric was 1.51 m N·cm(transverse)and 10.23 m N·cm(longitudinal),respectively.Crease recovery angles were 167.54°(transverse)and 134.57°(longitudinal),respectively.The elastic response rates were 90.23%(horizontal)and 91.66%(vertical),respectively.The hysteresis rates were 28.99%(horizontal)and 22.40%(vertical)respectively.Compared with polyester knitted fabric,the elastic recovery rate and hysteresis rate of spandex knitted fabric are greatly improved.The transverse elastic recovery rate of spandex knitted fabric is increased by 19.77%,while the transverse hysteresis rate is decreased by 24.21%.In order to reduce the hysteresis rate of the fabric,in the next chapter,the spandex coated yarn is selected as the raw material to weave the yarn into woven fabric.The third part mainly focuses on the selection of woven fabric structure,the preparation of elastic yarn woven fabric,heat setting experiment and performance characterization,and the optimization of technological parameters by orthogonal experiment.First,the same yarn as the second part,namely spandex coated yarn,was selected as the experimental material,and the tissue structure of the sample was selected as plain texture.Secondly,the sample of spandex plain fabric was prepared by weaving technology.According to the same range of heat setting parameters in the second part,the woven samples were treated with heat setting.Finally,the heat setting temperature of 180℃ and the heat setting time of 30 s were determined to make the spandex plain fabric with the optimal comprehensive performance.Then the sample was set by tension heat,and the sample was tested after treatment.Finally,it was determined that when 10% weft elongation was applied to the fabric,the comprehensive performance of the fabric was the best.The optimal heat setting parameters of spandex fabric were determined by orthogonal experiment as follows: the zonal flexural stiffness of spandex fabric was 4.57 m N·cm when the weft elongation was 15%,the temperature was 180℃ and the time was 45 s.The zonal fold recovery Angle is 147.65°.The zonal elastic recovery rate was 90.25%.The zonal hysteresis rate was 19.56%.Conclusion The heat setting effect of spandex woven fabric is good,and the hysteresis rate is reduced by 9.43% compared with that of spandex knitted fabric.