Research On Spinning Technology Of Polyamide 66 Core-spun Yarn And Development Of Denim Products

In the development of denim products,it is the development direction with market potential to develop denim products with excellent style and comfortable wearing by using new fibers and elastic fibers.Spandex elastic core-spun yarns are mostly used in elastic jeans.However,due to the poor strength and dyeing performance of spandex,there will be elastic damage caused by the breakage of spandex and the formation of coreless yarn in production and wearing.In order to use new raw materials to develop elastic denim products,viscose or lyocell from recycled cellulose is selected as the outsourcing fiber,and polyamide 66 with high strength and high resilience is selected as the core yarn of the core-spun yarn.Through the optimization of spinning process,36.4 tex,28 tex and 18.5 tex polyamide 66 core-spun yarn products are developed.Through the test weaving of denim fabric,wear-resisting,stretching,wrinkling and bending tests,the performance of denim fabric woven with different kinds of weft yarn was compared.The main research contents and conclusions are as follows:(1)Through the test and analysis of the performance of polyamide 66 filament,it can be seen that the type and specification of filament have great influence on the quality and performance of core-spun yarn.Polyamide 66(3.33 tex/10F)and polyamide66(3.33 tex/34F)are selected according to the calculation of core yarn content.The morphology of polyamide 66 filament was characterized,and then tensile and elastic properties were tested.It was found that the morphology of two kinds of polyamide 66 filament was different in the natural state,and the breaking strength,elongation at break and elastic properties of the former were better than the latter.(2)The spinning process of polyamide 66 core-spun yarn was studied and optimized.By using siro spinning process,12 varieties of polyamide 66 core-spun yarns with linear densities of 36.4 tex,28 tex and 18.5 tex were developed.Through microscope observation,computer image processing and yarn performance test,it is found that compared with lyocell,the cored yarn with viscose as the outer fiber has more uniform yarn,less yarn hairiness,better yarn coating effect,but slightly worse tensile performance.Compared with the polyamide 66(3.33 tex /34F)core-spun yarn,the tensile property of polyamide 66(3.33 tex /10F)core-spun yarn is better,but the yarn strip irregularity is slightly higher.The finer the core-spun yarn,the lower the yarn strength,the greater the strength unevenness,the lower the yarn evenness,but the hairiness of the core-spun yarn decreases,the better the yarn coating effect.(3)Through the comparative study of the performance of polyamide 66 corespun yarn and spandex core-spun yarn,the yarn strength and yarn elasticity of polyamide 66 core-spun yarn and spandex core-spun yarn of 36.4 tex and 28 tex were tested respectively,and it was found that the strength,breaking elongation,sliver and hairiness of viscose/spandex(4.44 tex)were not as good as the polyamide 66 core-spun yarn developed in this subject.The elastic recovery of nylon 66 core-spun yarn is better than that of spandex core-spun yarn under microelastic condition.Through the comparison of core-spun yarns with different fineness,it is found that the tensile properties of 36.4 tex polyamide 66 and spandex core-spun yarns are better than that of28 tex,but the evenness,elastic recovery rate and hairiness of the core-spun yarns are not as good as that of 28 Tex.(4)The weaving and style of polyamide 66 core-spun yarn fabric were tested and analyzed.Using rapier looms,the viscose/polyamide 66 and viscose/spandex corespun yarns of 36.4 tex and 28 tex were woven with pure cotton yarns of 36.4Tex and28 tex,respectively,to make denim fabrics.The denim fabric was tested for its strong elastic resilience,crease resilience,color fastness to bending and wear resistance.It is found that the viscose/polyamide 66 core-spun fabrics have certain advantages in tear strength and tensile strength,and the elasticity recovery of viscose/spandex core-spun fabrics reaches the level of viscose/spandex core-spun denim products.The softness of viscose/spandex core-spun fabrics is better than viscose/spandex core-spun fabrics,but the crease recovery rate is worse than viscose/spandex core-spun fabrics.28 tex viscose/polyamide 66 or viscose/spandex core-spun denim fabrics have less elastic recovery and crease recovery than their 36.4-tex counterparts,but they have better softness.The color fastness and wear resistance of polyamide 66 core-spun yarn developed in this project are up to the requirements of denim products.The polyamide 66 core-spun yarn developed in this paper has high strength,which makes up for the elastic damage of the spandex core-spun yarn caused by the breakage of the core-free yarn.At the same time,the elastic resilience of polyamide 66 core-spun yarn meets the needs of the public,and it is softer and more comfortable to wear than the denim products woven by spandex core-spun yarn.