Study On Knitting And Heat Setting Technology Of Melt-spinning Spandex Knitted Fabric

Spandex and its fabric are widely popular because of its excellent resilience,and the knitted fabrics containing spandex are absorption,breathable,soft etc.In recent years,with the government paying attention to environmental protection,and introduced regulations such as “water ten”,people environmental protection consciousness gradually got strengthened.Melt-spinning spandex got more attention because of its nontoxic,simple process and low production costs,and it will be the mainstream products in the future.In this paper,the characteristics of the melt-spinning spandex filament and the dry spandex filament were tested and analyzed.Mainly including the tensile properties and elastic properties of the yarns.To study the knitting of melt-spinning spandex knitted fabric,by kniting the plated yarn fabric with cotton,polyester,and polypropylene;The technology of heat setting of melt-spinning spandex knitted fabric was determined;By processing the melt-spinning spandex and dry spandex knitted fabric with dyeing and finishing,to study the dimensional stabilities and elastic properties of the fabrics.Firstly,this paper tested and analyzed the properties of three type of melt-spinning spandex filament and one dry spandex filament,mainly including the tensile properties and elastic properties of the yarns.The results show that the breaking strength and initial modulus of melt-spinning spandex filament are better than dry spandex filament.Moreover,the elongation at break and elastic recovery rate are lower.Moreover,this paper tested and analyzed the melt-spinning spandex filament thermodynamic properties by using DSC and heat setting.Secondly,to study the knitting of melt-spinning spandex knitted fabric,by plain plating knitted fabric with cotton,polyester,and polypropylene.The results show that the yarn rate of spandex and the surface yarn are directly influence the fabrics density and the rate of spandex.When the rate of spandex of fabrics are similar,the elastic recovery rate of the melt-spinning spandex knitted fabric are similar as the dry spandex knitted fabric.This paper determined the proper knitting technology of melt-spinning spandex knitted fabric.Thirdly,this paper using single factor and orthogonal experiment,explore the influence of heat setting temperature,heat-setting time,fabric expansion rate on fabric dimensional stability and elastic recovery performance.And got the best heat setting technology of melt-spinning spandex knitted fabric: cotton / melt-spinning spandex knitted fabric is 175℃ / 75 s / 5%;polyester / meltspinning spandex knitted fabric is 170℃ / 85 s / 9%;polypropylene / melt-spinning spandex knitted fabric is 120℃ / 60 s / 10%.Finally,this paper gave the melt-spinning spandex and dry spandex knitted fabric dyeing and finishing process,and tested and analyzed the fabrics dimensional stability and elastic recovery performance.The results show that with the same dyeing and finishing process,the fabric dimensional stability of the melt-spinning spandex and dry spandex knitted fabric are similar.After the dyeing and finishing process,the elastic recovery performance of cotton / spandex knitted fabric and polyester / spandex knitted fabric were decreased.After the heat setting process,the elastic recovery performance of polypropylene / spandex knitted fabric was increased.