Impact of structural variations in hollow yarn on heat and moisture transport properties of fabrics

The use of hollow/microporous yarns plays an important role in enhancing the thermo‐physiological comfort properties of fabrics. Depending on structural variations in hollow yarn, heat and moisture regulation behaviours of fabrics can be affected significantly. In this study, three types of hollow cotton yarn fabrics, produced by introducing polyvinyl alcohol (PVA) filament in the core, PVA staple fibres in the blend and PVA filament in doubling with cotton spun yarn, are studied. All three types of pre‐hollow yarns and reference yarns are made with a variation in spinning technique (single roving/double roving) to prepare eight single jersey knitted fabrics. The hollow/microporous structure of the yarn is created by dissolving the PVA fibres using hot washing of the fabrics. On overall evaluation of the fabric’s thermo‐physiological comfort properties, the doubled hollow yarn fabrics are found to be better than other fabrics. In general, thermal resistance, thermal absorptivity, wicking and drying properties of all types of hollow yarn fabrics increase after repeated laundering, while air permeability, water vapour permeability and water absorbency of hollow yarn fabrics mostly decrease. In contrast with fabrics made from yarn produced through single roving technique, use of double roving technique only improves fabric water vapour permeability.     

集聚纺和环锭纺细纱及织物的芯吸性能

评价了集聚纺和环锭纺细纱及其织物的芯吸性能。实验结果表明,环锭纺芯吸比集聚纱快,由环锭纱制成的织物比集聚纱制成的织物芯吸快,纱线中纤维排列太紧从芯吸的角度来讲是不利的。     

Physical properties of ring,compact, and air vortex yarns made of PTT/wool/modal and wearing comfort of their knitted fabrics for high emotional garments

This study examined the physical properties of PTT/wool/modal yarns according to the yarn structure and the wearing comfort of their knitted fabrics for high emotional garments. For this purpose, the air-vortex, compact, and ring yarns and their knitted fabrics were prepared to analyze the wear comfort according to the yarn structure and the possibility of applications of the PTT/wool/modal blend fibers to air-vortex yarn. The wicking and drying rates of the air-vortex yarn knitted fabrics were superior to those of the ring and compact yarns fabrics, and the heat-keeping capability of the air-vortex yarn knitted fabric was higher than those of the ring and compact yarns fabrics due to the low thermal conductivity and maximum heat flow rate. In addition, the pilling of the air-vortex yarn knitted fabric was less than those of the ring and compact ones due to the air-vortex yarn structure with parallel fibers in the core part and the periodical and fasciated twists on the sheath part of the yarns. The tactile hand of the air-vortex yarn knitted fabric was harsher than those of the ring and compact yarns knitted fabrics because of the low extensibility and compressibility, and the high bending and shear rigidities.     

Mathematical model to predict vertical wicking behaviour. Part II: flow through woven fabric

The aim of the paper is to develop a mathematical model to predict vertical wicking behaviour of woven fabric. The first part of this series (Part I) has dealt with the mathematical model for predicting vertical wicking through yarn. In this part a model has been proposed to predict vertical wicking of the woven fabric, based on the developed yarn model. In order to model the flow through woven fabric along with the vertical flow through liquid carrying threads, the horizontal flow through transverse threads has also been taken into account. A simplified fabric geometrical concept (inclined tube geometry) and Peirce geometry for plain woven fabric have been used to define the fabric structure. Warp and weft linear density, fabric sett and yarn crimp have been considered in the fabric modelling. The theoretical wicking values of the yarn and fabric made from that yarn have been compared. Experimental verification of the model has been carried out using polyester and polypropylene fabrics. The model is found to predict the wicking height with time through the yarns and fabrics with reasonable accuracy.     

水分沿针织物纵横向传递速度的研究

采用同一种棉纱织成6种同组织不同结构的针织物,运用水平芯吸的实验方法,分别测试水分沿针织物纵横向的芯吸速率,发现芯吸高度h与时间t可以很好地用h=atb表示.通过线性回归得出织物结构参数--纵密、横密、织物厚度对芯吸速率的影响,结果表明针织物的芯吸不能简单地用毛细上升的规律来描述.在织物结构参数影响中织物厚度的影响最大,织物越厚,芯吸速率越小;织物纵密、横密越小,芯吸也加快.此外,也对针织物的芯吸规律进行了一些探讨.     

The Air-permeability Measurement of Open Fabrics by Using Superimposed Fabric Layers

An account is given of an investigation of the dimensional properties of a series of plain weft-knitted fabrics produced from open-end-spun yarns. The results are compared with those for similar fabrics knitted from ring-spun yarns.

It is shown that fabrics knitted from the two types of yarn possess different properties and particularly that the amount of relaxation shrinkage observed in fabrics knitted from open-end-spun yarns is greater than that which occurs in fabrics knitted from ring-spun yarns. The aesthetic properties of fabrics made from open-end-spun yarns are inferior to those of fabrics made from ring-spun yarns, particularly with regard to a lack of stitch clarity and a somewhat harsher handle, although the latter effect is shown to be apparently unrelated to differences in the frictional properties of the two types of yarn.     

Thermo-physiological comfort characteristics of polyester air-jet-textured and cotton-yarn fabrics

Air-jet-textured polyester yarns were produced using two feed yarns differing in filament fineness and number of filaments. By varying the overfed rates of feed yarns and changing their positions in core and effect, five textured yarns were produced. Woven fabrics were prepared using these textured yarns as weft and cotton yarns in warp. To study the effect of air-jet-texturing parameters on the thermo-physiological comfort characteristics of fabric, the woven fabrics were tested for thickness, thermal properties, transverse wicking and air permeability. It is observed that thermal conductivity and resistance of fabrics are not influenced by the texturing parameters/textured yarn structure. These properties are mainly dependent on the entrapped air present in fabrics. Thermal absorptivity is a transient phenomenon of heat flow reflecting that the ‘warm-cool feeling’ effect of fabrics depends on smoothness/roughness of fabric surface. Fabrics with smooth surfaces have higher thermal absorptivity values as they provide a large area of contact with human skin. The roughness of fabrics depends on the number of surface loops and filament fineness. Transverse wicking of fabrics depends on the size, continuity and alignment of the capillaries present in the core of textured yarns.     

Effect of Pique and Honeycomb Structures on Moisture Management Properties of Eri Silk Knitted Fabrics

ABSTRACT

The present study aims to investigate the moisture management and wicking properties of eri knitted fabrics. In this study, two different knit structures, namely, single pique and honeycomb fabric, were developed with the combinations of two different tightness values of slack and tight by using 2/80s Nm and 2/140s Nm eri silk yarns. The developed fabrics were analyzed for vertical wicking, moisture management properties such as wetting time, spreading speed, absorption rate, maximum wetting radius, accumulative one-way transport index (AOTI), and overall moisture management capacity (OMMC). Variables such as yarn linear density, tightness, and knitting structure have a significant influence on the wicking and moisture management properties. The overall OMMC indices of eri silk knitted fabric lie in the ‘very good’ to ‘excellent’ category, indicating the suitability of eri silk yarn for skin fit as well as active wear applications.     

仪纶~(TM)纬平针织物的抗起毛起球性能

本文分别选用环锭纺、赛络纺、赛络紧密纺纺纱工艺,制备了同等纱支的仪纶~(TM)纯纺、仪纶~(TM)/棉(65/35)混纺针织纱线及其纬平针织物,对比测试了纱线性能及其织物抗起毛起球性能。实验结果显示:不同纺纱工艺的仪纶~(TM)针织纱线总体性能相似,赛络紧密纺纱线纱体结构更均匀;赛络纺织物的抗起毛起球性较环锭纺织物高0.5级,赛络紧密纺织物的抗起毛起球性明显好于环锭纺织物;混纺织物的抗起毛起球等级和起球粒数均有所改善。     

The dimensional and mechanical properties of wool/polyester fabrics made from vortex and ring-spun yarns

Fabric woven from wool/polyester (PES) Murata vortex spun (MVS) blend yarn is a commercially viable proposition particularly on the basis of advantageous wear-resistant properties, compared with fabric made from traditional worsted ring-spun yarn. However, in some early industrial trials with fabric made from 45/55-blend wool/PES MVS yarn, significantly greater relaxation shrinkage was found relative to comparable worsted ring-spun fabric. It was noted at the time that the amount of relaxation shrinkage in MVS fabric could be reduced to a large extent by using steamed MVS yarn.

In this study, the extent of variations in the dimensional and mechanical properties of fabric samples woven from a combination of steamed and unsteamed MVS yarn and equivalent worsted ring-spun yarn is examined. In general, greater hygral expansion and relaxation shrinkage were found in loom-state fabrics made from unsteamed MVS yarns, whereas the fabric made from steamed MVS and ring-spun yarns gave relatively low levels of relaxation shrinkage and hygral expansion. Permanent setting of fabrics, by pressure steaming, was found to be more effective than yarn pre-steaming in reducing relaxation shrinkage levels of fabrics made from unsteamed MVS yarn. After pressure steaming, all fabrics showed similar levels of relaxation shrinkage and hygral expansion.

Permanent setting of the fabrics, by pressure steaming, resulted in similar levels of relaxation shrinkage and hygral expansion, irrespective of the yarn production method; relaxation shrinkage fell to around 1% and hygral expansion increased by about 1%, relative to the loom-state samples. MVS fabrics were relatively heavier and fuller and had a firmer handle than the worsted ring-spun fabrics, reflecting the greater fabric weight, thickness and shear rigidity measured on these fabrics. These attributes are associated with different structures of the worsted ring-spun and MVS yarns used to make the fabrics.     

Investigation on permeability and moisture management properties of different denim fabrics after repeated laundering

The physiological comfort determined by air permeability and moisture management properties of fabrics is influenced by various constructional parameters of the fabric which give woven fabric a porous structure. Evaporation of sweat during wear has the potential to cool the body besides restricting the additional weight of sweat being absorbed by the fabric. In this study, comfort characteristics of denim fabrics with different weft yarn of cotton, polyester and core spun Lycra have been discussed. Effect of enzyme washing and repeated laundering on air permeability, moisture management and drying rate has also been discussed. It was observed that air permeability and water vapour permeability of unwashed denim fabrics with cotton weft yarn are significantly higher than the fabric with polyester and Lycra cotton weft yarns. The wetting time is higher for cotton and Lycra cotton yarn fabrics. One-way transport index is highest for Lycra cotton weft fabrics and lowest for fabrics with polyester weft. Fabrics with polyester weft yarns show highest spreading rate, spreading radius and drying rate due to better wicking and hydrophobic nature of polyester fibres.     

Development of mathematical model to predict vertical wicking behaviour. Part I: flow through yarn

Theoretical models have been proposed in this article (Parts I and II) to predict the vertical wicking behaviour of yarns and fabrics based on different fibre, yarn and fabric parameters. The first part of this article deals with the modelling of flow through yarn during vertical wicking, whereas the second part deals with the modelling of vertical wicking through the fabric. The yarn model has been developed based on the Laplace equation and the Hagen–Poiseuille’s equation on fluid flow; pore geometry has been determined as per the yarn structure. Factors such as fibre contact angle, number of filaments in a yarn, fibre denier, fibre cross‐sectional shape, yarn denier and twist level in the yarn have been taken into account for development of the model. Lambertw, a mathematical function, has been incorporated, which helps to predict vertical wicking height at any given time, considering the gravitational effects. Experimental verification of the model has been carried out using polyester yarns. The model was found to predict the wicking height with time through the yarns with reasonable accuracy. Based on the proposed yarn model, a mathematical model has been developed to predict the vertical wicking through plain woven fabric in the second part of this article.     

A Study on Wicking in Natural Staple Yarns

In this study, natural staple yarns of cotton and wool were investigated for wicking properties. Fibre packing density reflected by yarn wicking rates was measured in ply cotton yarns. It was seen that with the samples measured in this work, both twist level and number of ply in a yarn can affect yarn wicking behavior. When twist and yarn count remained unchanged, wool yarns with different fibre diameters were measured for wicking rates and the best wicking was found on the yarn with the coarsest fibre diameter. Comparison was made in this work on the treatment methods, and on both synthetic continuous filament yarns and the natural staple yarns. While prewash treatment could improve yarn wicking by changing fibre surface condition, plasma treatment was a more effective way in increasing yarn wicking rate for both filament yarns and staple yarns.     

Studies on cotton-acrylic bulked yarns produced from different spinning technologies. Part II: fabric characteristics

The present work is concerned with the study of the characteristics of plain woven fabric produced with cotton-acrylic high-bulk yarns from different spinning technologies. The effects of different factors, namely spinning technologies (ring, rotor and DREF-II, i.e. Group A fabrics), position of shrinkable acrylic feed sliver in DREF-II friction spinning system (Group B fabrics) and proportion of shrinkable acrylic core fibre in core-sheath type DREF-III friction spun yarns (Group C fabrics) on various properties of cotton-acrylic blended bulked yarn fabrics have been reported. The influence of these three variables on the mechanical, handle and comfort properties of fabrics have been studied. The properties of fabrics made of bulked yarns from different spinning technologies are found to be different from the normal 100% cotton yarn fabrics in all respect. Even though the bulked yarns were used only in weft direction, the fabrics with modified yarn structures show appreciable improvement in thermal resistance, moisture vapour transmission, wicking and air permeability. The bending rigidity of the fabrics in weft direction also reduced with improvement in crease recovery in weft direction.     

Studies on moisture transmission properties of PV-blended fabrics

Moisture transmission properties are most important for fabric comfort. We have studied the moisture transmission properties of the plain-woven fabric produced with polyester–viscose-(PV) blended yarns. PV-blended yarns of varying blend proportion, yarn count and twist levels have been used for fabric manufacture. A three-variable Box and Behnken factorial design technique has been used to study the interaction effects of the above variables on the aforesaid characteristics of fabrics. The interactive effect of these three variables on the air permeability, water vapour permeability, in-plane wicking and vertical wicking of PV-blended fabrics has been studied and the response surface equations for all the properties have been derived; also, the design variables have been optimized for all the moisture transmission-related properties. Most of the moisture transmission characteristics were found to be affected significantly by blend proportion, count and twist levels at 95% level of significance with the present variables.     

加捻对不同涤纶长丝芯吸性能的影响

以毛细效应和湿蒸发原理为基础 ,对不同截面形状和加工方式的涤纶长丝在不同捻度条件下芯吸高度的变化规律进行了实验研究。结果表明 :特殊异形截面涤纶长丝较圆形截面的芯吸效果好 ,加弹丝的芯吸效果好于平牵丝 ,捻度对长丝芯吸性能的影响呈Lorentzian曲线变化规律     

碱处理对异形截面聚酯纱线芯吸效应及强力的影响

针对氢氧化钠可破坏聚酯纤维结构,影响异形截面聚酯纤维的芯吸效应、润湿性、强力、伸长性能和吸湿快干及吸湿凉爽功能这个问题,借助扫描电子显微镜,对氢氧化钠处理前后的纤维形态结构进行了表征,分析了影响该纱线芯吸效应的因素,研究了不同质量分数碱处理对异形截面聚酯纱线芯吸效应、润湿性能、强力及伸长的影响规律。结果表明:异形截面聚酯纤维横截面为十字形,沿纤维纵向有4道沟槽,起到毛细管作用,为水分的迁移提供了通道,使纤维及纱线具有良好的芯吸效应;氢氧化钠可有效清除异形截面聚酯纤维沟槽中的低聚物,当氢氧化钠质量分数在4%左右时,纱线芯吸效果显著提高;氢氧化钠处理可提高异形截面聚酯纱线的润湿性;随着氢氧化钠质量分数的提高,异形截面聚酯纱线强力及伸长下降,当氢氧化钠质量分数高于6%后,纱线的强力和伸长损失显著。     

Wetting and Wicking in Fibrous Materials

This issue reviews developments in wetting and wicking of fibrous materials, covering characterization of wetting; wetting and wicking of fibers, filaments, yarns, and fabrics; factors affecting wetting and wicking of fibrous assemblies; mathematical models of wetting and wicking; and application areas of the same.     

Study of wicking behavior of water on woven fabric using magnetic induction technique

An apparatus for measuring the wicking rise of water in fabrics has been developed and several types of fabrics were examined. The method is based on the electromagnetic field induction due to wicking penetration of water into capillary spaces of fabric samples. The measuring system is coupled with a personal computer, and the distance of water rise as a function of time is determined. Plain woven fabric samples with different weft yarn counts, density, and type of fiber in blend yarn were examined. The results obtained by wicking measurement were compared with water vapor permeability index data and the test method for wettability of textile fabrics on the same samples. The average wicking rise of water decreases with the increase of weft yarn density. The wicking of water along the cotton–polyester blend weft yarn is higher than 100% cotton weft yarn samples. The relation of water vapor permeability (WVP) index and the test method for wettability of the same fabric samples show the same behavior as the wicking rise. The equivalent geometric factor neglecting the Earth’s gravitational field is calculated by the average slope L ²/t from the experimental data of wicking of water into the samples. The radii of open channels in the woven fabric sample tends to decrease as a result of increasing weft yarn density.     

Effect of Yarn Type and Twist Factor on Air Permeability,Absorbency, and Hand Properties of Open-end and Ring-spun Yarn Fabrics

The paper investigates the effects of yarn type, i.e. open-end yarn (OE) and ring-spun yarn (RS) and the twist factors of the warp (W) and filling (F) of the OE yarns on the permeability to air and moisture and the hand properties of various test fabrics woven from both OE and RS yarns. A comparison is made of the effect of yarn types and various twist levels of warp and filling of the OE yarns on the air permeability, absorbency, coefficient of friction and flexural rigidity of fabrics woven from such yarns.

It is intended that future studies will explore a wider range of twist levels and different yarn types than those investigated on this initial exercise.