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The Study on High-Gauge Warp Knitting Suitability of Wool Underwear and Its Wear Performance

Author: LinFangFang
Tutor: ChenNanLiang
School: Donghua University
Course: Textile Engineering
Keywords: wool fiber slenderized by drawing compact-spinning yarn warp knit with high gauge production technology wear performance
CLC: TS186
Type: Master's thesis
Year: 2012
Downloads: 19
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Abstract

Wool fabrics have been ranking among upmarket wear fabrics with its excellent resilience, strong moisture absorption ability as well as high warmth retention. The production of worsted wool yarn enables the development of light-weight wool knit fabric.Presently, weft knitting technology has been used to knit light-weight wool fabrics, among which most are weft plain ones. In this study, research on the knitting suitability of wool yarn on the high-gauge warp knitting machine is conducted and several high count warp-knitted wool fabrics are designed, aiming to increase varieties of wool knit products as well as to further enhance the added value of wool textiles.In this study, compact-spinning yarn of wool slenderized by drawing was selected and following tasks have been completed subsequently:(1) Such performances of compact-spinning yarn of wool slenderized by drawing as irregularity, hairiness appearance, tensile characteristic and stretch plastic deformation characteristic are tested and analyzed through comparing with that of compact-spinning yarn of lower count wool fiber. (2) The main sources of tension change as well as additional tension generation in the knitting process are analyzed, influences of additional tension on friction damage of wool yarn are predicted and subsequently the regression analysis is done to set up the relationship between additional tension and friction speed with the priority being indicated. (3) Several wool products knitted by both single bar and two bars are developed, such process parameters as beaming tension, beaming speed, knitting texture, amount of yarn let-off and knitting speed are adjusted and rationally set in terms of production practice, and effective methods of tension compensation and hairiness diminution are also discussed. (4) A series of mechanical properties of wool warp knit fabric are comparatively tested with that of weft plain fabrics with similar gram weight, including bursting, stretch resilience, dimension stability under machine washing and pilling resistance tests. Indexes of clothing wetness and heat comfort, such as air permeability, moisture permeability, moisture absorption speed constant, drying rate and coefficient of heat transfer are also comparatively tested, using fuzzy math model to evaluate the advantages and disadvantages of warp knit wool fabrics developed in the study, aiming to provide references for further study on follow-up products.Following conclusions have been drawn:(1) The breaking strength and elongation of compact-spinning yarn of wool slenderized by drawing, especially its elongation rate are improved and its comprehensive hairiness index is lower, which enable it to meet theoretical requirements of yarns used in warp knitting process. (2) The amount of yarn let-off should not be too low, considering the strength of wool yarn is comparatively weak. The initial knitting tension had better be controlled between 10cN and 20cN. Additionally, choose short transverse distance of yarn guide bar as far as possible. The best knitting speed is around 400r/min. (3) The surface of two-bar fabric form more hairiness than that of single-bar one. (4) In terms of wear performances, the bursting strength of atlas fabric is lower than that of weft plain one with similar gram weight and same yarn count, while the former’s stretch resilience, dimension stability under machine washing as well as pilling resistance are better than the latter, the former’s comprehensive wetness and heat comfort is also better than the latter. Both mechanical properties and comprehensive wetness and heat comfort of double rib and double atlas are superior to that of weft plain ones with similar gram weight and lower yarn count. On the condition of similar gram weight, weft plain wool fabric with higher yarn count has higher coil density, which contributes to the improvement of the fabric’s stretch resilience and pilling resistance performances, causing worse comprehensive wetness and heat comfort in the other hand.

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