Study On The Reasons Of Sewing Needle-Hole Of Knitted Cotton Fabric And Its Improving Methods

Sewing needle holes is one of critical factors affecting the quality of apparel appearance. The control of needle holes has puzzled garment industry for decades during sewing control. To solve this problem, both domestic and foreign scholars have made a lot of efforts and achieved many good results. Nevertheless, this phenomenon still exists. This paper began with the formation mechanism of the needle-hole, combining with previous work and analyzed the causes of sewing damage for a series of knitted materials used commonly in order to reduce the occurrence of holes dramatically during practical manufacturing.Firstly, in this thesis, common yarn was finished by different auxiliaries selected, and some properties, such as the sliding friction coefficient between yarn and metal parts and yarn strength, were tested and analyzed. The result showed that auxiliaries had a great effect on yarn sliding friction coefficient and strength while little effect on other properties. Oxidized polyethylene waxes of auxiliaries could reduce greatly sliding friction coefficient, meanwhile, the decrease rate of Yarn strength was within the range allowed. On the other hand, different fabric structure and density were knitted to be jersey, interlock and rib by selecting the appropriate process parameters, engaged in pretreatment, dyeing and heat setting and measured physical indicators after some time.Secondly, the paper focused the effect factors of sewing needle-hole on the Needle size, fabric density and thickness and other factors. The result indicated that itwas more likely to occur needle-hole for sharp needlepoint than round needlepoint during sewing, that was because round needlepoint could push the yarn of fabric smoothly and fiber was not easy to be damaged. The same needlepoint shape, the greater the needle size, the more the needle holes. In the case of the same fabric space, the thicker the needlepoint, the easier to cut off the yarn when sewing. Besides, the greater the fabric density and the closer the loop structure of the fabric, the more prominent needle-hole problem when sewing, what is more, the number of needle-hole increased with the increasing of fabric thickness.In order to obtain the best finishing result, the Finishing auxiliary 680 was selected as representative and analyzed the effect of the process factors on interlock fabric by the of orthogonal design method and determine the optimum:Additive concentration 2%,40℃,30min, Bath ratio 1:10. he optimum finishing process dealt with common rib knitted by three soft and smooth agents such as 680,682+ and 55E,and then sewability tested. The result showed that the sewing performance of the fabric was improved after finishing additives. RUCOWAX EMULSION 680 was the best among additives and needle holes were least on the knitted fabric. Next, we combined 682+ with 55E at the rate of 2:1 and gain the best sewability effect.Finally, we tested the wearability after finishing and the analysis result showed that parts of the performances were improved to some extent.