Development Of Knitted Polo Shirt Collar With High Dimenional Stability Using TPU Monofilament

Polo shirt adopts flat knitting collar,which is usually a 1×1 rib structure knitted with nylon/spandex covered yarn and cotton yarn simultaneously.In the process of washing and wearing,the elasticity loss or even fracture of the covered yarn leads to wrinkle and curl,which seriously affects the appearance and services life of the Polo shirt.A novel flat knitting collar with high dimensional stability in the form of cotton as sheath and TPU as core was made of high shrinkage TPU monofilament with good elasticity and excellent thermo-plasticity by using plated 1×1 rib stitch.In addition,partial knitting technique was used to pre-knit the crease of the collar by changing the yarn and stitch to automatically form the three-dimensional shape.The combination of the two techniques can produce a fully formed flat knitting collar with superior dimensional stability.The main research contents presented in this thesis are as follows.First,the breaking strength and tensile elasticity of different TPU monofilaments and nylon/spandex covered yarn were evaluated.Collar fabrics were then manufactured by using cotton as face yarn and TPU monofilament or nylon/spandex covered yarn as plating yarn.The crease recovery angles of the fabrics in different angles and repeatedly folded at different times were measured.Afterwards,a total of 28 samples were prepared by using different Needle Positions(NP),fabric take-down tensions and yarn feeding tensions of TPU monofilament in knitting,and different temperatures,duration and pressplate gauge in heat setting.The wrinkle resilience,tensile resilience,permeability and bending rigidity of the fabrics were tested and compared.A set of optimal knitting and heat setting process parameters was determined.Next,the fully knitting plan to form a specific crease of collar was determined by fitting the actual crease line of a collar and formulating the arrangement of stitch courses and wales.Finally,a complete set of knitting and heat setting parameters,and fully fashioning method was achieved to prepare the high dimensional stability knit collar of Polo shirt by combining the two techniques.From the experimental studies presented in this thesis,it was found that the high shrinkage TPU monofilament has good knittability and elastic recovery.Its irrecoverable elongation after stretching is only about half of nylon/spandex covered yarn,and this advantage is still obvious after cyclic stretching.The 1×1 rib fabric containing TPU monofilament became more isotropicand wrinkle resistance when folded,and its advantages were still obvious after cyclic folding.In addition,the crease recovery angles of the fabric containing TPU monofilament and nylon/spandex covered yarn after folding in different directions are significantly different,and the crease recovery is the worst when the angle form between longitudinal line and crease range from30° to 45°.This angle range is consistent with the angle of collar curling.The overall performance of the collar fabric is satisfactory when the NP value,fabric take-down tension,TPU yarn feeding tension,the heat setting temperature,duration,and pressplate gauge are 9.5,1.83 N/100 stitches,15 cN,180?,10 seconds and 1.0 mm,respectively.It was also found that when the temperature is 150?,TPU monofilament had good thermo-plasticity and can be heat set into a highly regular "wavy shape",which improve the shape retention of the collar.When the temperature reached 180?,the TPU monofilament was partially melted.Cotton loops and TPU loops are bonded to a certain level which greatly enhanced the isotropy of the collar,and the elastic recovery capacity of the stretch can be increased by 10 times compared with that of the fabric covered with nylon/spandex.The air permeability of the collar fabric was not reduced by adding TPU monofilament.On the contrary,the air permeability is better than that of the fabric knitted with nylon/spandex covered yarn.Moreover,the addition of TPU monofilament only slightly increased the fabric transverse bending stiffness which had little effect on the wearing comfort of the collar.By contrast,the longitudinal bending stiffness of the fabric was remarkedly increased,and the maximum stiffness was about 3 times of that of the fabric containing nylon/spandex covered yarn,thereby improving the shape retention of the collar.