Research On Reducing Elastic Treatment And Product Development Of Nylon DTY

As one of the most important materials in the textile industry,nylon has been oversupplied in recent years in China,and the demand for increasing the added value of downstream products of nylon has intensified.Nylon 6DTY has the appearance of curling and fluffy and excellent wear characteristics,but its poor unwinding ability limits its application in the spinning field to a certain extent.On the other hand,with the upgrading of the domestic textile industry,composite yarn,structural yarn,functional yarn,fancy yarn,etc.,have become a hot field of product research and development due to their unique performance.For example,lightweight,breathable,soft and warm hollow yarn,the previous technology of spinning core-spun yarns using water-soluble vinylon and obtaining hollow yarns through dissolving water-soluble vinylon after spinning has been relatively mature,but there are generally defects such as high production costs and insufficient shape preservation;As a typical variety of fancy yarn,slubby yarn has a unique appearance and tactile style,but its spinning method is relatively simple,mainly relying on roller speed changes,with high mechanical requirements and cumbersome adjustment of appearance factors;In addition,there is still a lack of development of slubby cored yarn and insufficient research on using the elastic filaments as the core yarn.Focusing on the above research progress,this topic proposes to use nylon 6DTY with significant diameter differences in the relaxed and straightened state as a core yarn to support the cotton fibers in the sheath,thereby developing a hollow yarn with good shape retention;And to develop a new slubby yarn spinning process without relying on roller speed changes by using nylon 6DTY as a core yarn after being segmented and fixed in the relaxed and stretched states.Therefore,this topic first proposed the concept of reducing elastic treatment,which is to maintain the curly shape of the tow by relaxing sizing.On this basis,research is mainly carried out from the following aspects:The research on the design of reducing elastic treatment device shows that the self built pre treatment device for elastic reduction is composed of a yarn frame that can adjust the vertical height of the bobbin from left to right,a yarn guide rod,a sizing groove with a fixed pressure roller,and a hexagonal yarn frame that rolls the elastic reduction yarn clockwise;By constructing a theoretical resistance model,it can be seen that in order to avoid excessive elongation of the slack tow and stable packaging,metal rollers should be selected for the guide rod and pressure roller,and rubber sleeves should be installed on the winding frame.The liquid level of the slurry tank should match the position of the machine,maintaining the tangent line between the contact point of the tow and each machine part to the center of the machine to maintain a minimum friction state;The distance between the cross bars of the winding frame is preferably 10 cm,so that the elastic yarn does not sag,has fewer defects,and is highly efficient.Through testing and analyzing the properties of 24 types of elasticity-reduced yarn,including four specifications nylon 6DTY of 2.2tex/24 F,7.8tex/24 F,7.8tex/68 F,and15.6tex/48 F,two kinds of sizing agent(corn starch and PVA1788),and three sizing concentration(4/6/8%),the optimal size concentration was determined to be 6%.At this concentration,7.8tex/24 F and 7.8tex/68 F have large diameter increments,and have good evenness,mechanical properties,and wear resistance.The comprehensive properties are most suitable for subsequent spinning of core spun yarn.The spinning of hollow yarn uses corn starch and PVA 1788 with a concentration of 6%as the sizing agent,and four different forms of reduced elastic yarn made from 7.8tex/24 F and7.8tex/68 F as the core yarn.A total of 12 types of cotton/full reduced elastic yarn core-spun yarns are prepared by Siro spinning with a core yarn content of 20%,25%,and 30%.The hollow yarns obtained after desizing were tested and analyzed,and ranked according to the grey correlation degree evaluation.The first three places were 7.8 tex/68 F+PVA,with a core yarn content of 25%;7.8tex/68F+PVA,core yarn content 20%;7.8tex/24F+starch,with a core yarn content of 25%.In the trial spinning of slubby yarn,a grouting groove is added to the surface of the woven wiring board.The length and pitch of the slub can be controlled by changing the width and spacing of the groove.The elongate core-spun yarn with 6% corn starch+7.8tex/68 F intermittently reduced elastic yarn as the core yarn and the fluffy slub yarn with 6% corn starch+15.6tex/48 F intermittently reduced elastic yarn as the core yarn were spun using Sirofil spinning.After desizing,the single yarn strength reached the standard for slub yarn,with a clear appearance of slub yarn effect and a softer and lighter feel,but the hairiness deteriorated seriously.Finally,a trial weave of plain woven fabric was conducted using a hollow yarn with7.8tex/68F+PVA,a core yarn content of 25%,7.8tex/24F+starch,and a core yarn content of 25%as weft yarns.Compared with pure cotton plain woven fabrics with the same specifications and weaving parameters,the test results showed that the woven experimental fabric did have a hollow effect,and the fluffy structure of the weft yarn made it more lightweight and soft,with better air permeability,moisture absorption,and warmth retention than pure cotton fabrics,The strength of the corresponding hollow yarn fabric has decreased.After desizing,the thickness of hollow yarn fabric does not change much,indicating that the presence of DTY has a supporting effect,making the fabric have good shape retention.7.8tex/24F+starch,with a core yarn content of 25% weft yarn,has a significant DTY support effect,higher hollowness,and better warmth retention,but its uniformity is not as good as 7.8tex/24F+starch,with a core yarn content of 25%weft yarn,and its breaking strength is also lower.This topic has opened up a new field of downstream application of nylon 6DTY,developed low-cost and good shape retention hollow yarns,and proposed a new slub yarn process to improve the added value and market competitiveness of the yarn,which is more in line with the future development prospects and the dual pursuit of quality and cost in the market.