The effect of yarn twist direction on the formability of woven fabrics

This experimental work examines the influence of the yarn twist on the formability of a woven fabric. Consideration is given to the phenomenon of bedding between warp and weft yarns, as affected by the local helix angles of bent yarns. A total of 28 plain weave woven fabrics (four groups, each with seven samples) were produced, using Solospun? yarns as warp and weft threads. The fabric bending length and the initial modulus of each sample were measured from which the formability was calculated. Results indicated that the fabrics in which the warp and weft twists are unidirectional (Z &; Z) have higher formability in comparison to those fabrics in which the warp and weft twists are opposite to each other (Z &; S). In addition, among the former fabrics the highest formability belongs to those in which the total helix angle of the warp and weft is close to 90 degree whereas the lowest formability belongs to the latter fabrics with least amount of twist.     

Effect of structural parameters of porous yarns and fabric on air permeability and moisture transfer of double-face woven fabrics

In this study, effect of fabric structural parameters of double-face woven fabrics including kind of porous yarn namely micro-porous yarn and hollow yarn, hole size of hollow yarn, percentage of these yarns in double-face woven fabric structure, and finally weft density on air permeability and moisture transfer of woven fabrics was evaluated. These yarns were produced by using water-soluble continuous polyvinyl alcohol filaments as core part for hollow yarns and as doubling yarn in micro-porous yarn. Results revealed the effect of kind of porous yarn, hole size of hollow yarn, and weft density on air permeability and moisture transfer of woven fabrics. The percentage of porous yarns as weft did not show obvious trend. Analysis of variance was used to study the effect of these variables on air permeability and moisture transfer of double-face woven fabrics statistically.     

Total porosity,theoretical analysis,and prediction of the air permeability of woven fabrics

Air permeability is one of the most important properties of textile materials that ensure their comfort. For many materials for technical applications (filters, sails, vacuum cleaners, parachutes, etc.), this is one of the main properties that determine their quality. The air permeability of woven textile fabrics depends on many parameters of fabric. Thus, the determination of air permeability of woven fabric is highly complex and difficult. In this study, we attempted to establish a theoretical model for the porosity and predicted the air permeability of woven fabrics. A theoretical model was created to predict the total porosity and the air permeability of a fabric structure depending on the geometrical parameters such as pore size, warp density, weft density, fabric thickness, number of yarn, diameter of yarn, and fiber density. For the purpose, a theoretical model of porous systems on D’Arcy’s law was used, and the validity of the model was confirmed by experimental results using 100% cotton and 97/3 cotton/lycra woven fabrics. Since the amount of air passing through both the pores between yarns and the interstices in the fibers constituting the yarn structure was calculated, theoretical values of air permeability were obtained very close to the experimental values.     

Analysis of mechanical and dimensional properties of the denim fabrics produced with double-core and core-spun weft yarns with different weft densities

Elastic structures are preferred for improving the elasticity and recovery properties of denim fabrics. With the intention of improving comfort during body movements in denim jeans, 10–35% elasticity is required. In this study, the effect of the composition of double-core (dual-core) and core-spun weft yarns and weft density on the mechanical properties of denim fabrics was investigated. For this purpose, different core materials were used in the production of elastic yarns. The sheath material was cotton for all yarn types. Yarn samples were spun with the same yarn count and twist coefficient. 100% cotton Ne 8/1 Ring slub warp yarns were used as warp yarn while double-core and core-spun yarns were used as weft yarns in weaving. The weaving process was performed with three different weft density values (16, 22, and 28 weft /cm) and the other production parameters were kept constant. Twill 3/1 woven fabrics were treated according to standard denim finishing procedures. After domestic washing processes, mechanical properties of the samples were tested and statistically evaluated.     

Weft Insertion on Air-jet Looms: Velocity Measurement and Influence of Yarn Structure Part II: Effects of System Parameters and Yarn Structure

An investigation of the effects of different weft–insertion–system parameters on yarn velocity is reported. Increasing the air–supply pressure, initial loop length, and running speed decreases the total insertion time and hence increases the average yarn velocity.

To examine the effects of yarn characteristics on yarn velocity, several yarns were tested under the same laboratory conditions. For every yarn, relations between total insertion time, yarn velocity, and air velocity and distance were obtained. It was found that open–end–spun (OE) yarns had a higher yarn velocity than ring–spun (R) yarns owing to the bulkier structure. However, R yarns had a higher initial acceleration than OE yarns. Murata air–jet–spun yarns had a higher velocity than R yarns.

Increasing the yarn linear density and twist increased the insertion time. Texturing of continuous–filament yarns increased the yarn velocity by comparison with straight continuous–filament yarns.     

玻璃纤维经编成圈编织性能

针对玻璃纤维纱线在经编成圈编织时易受损、不易形成织物的现象,通过对不同生产机型、不同规格纱线的编织试验,探讨了经编成圈机构、送经机构和牵拉机构、纱线捻度、捻向及玻纤浸润剂类型等因素对玻璃纤维编织性能的影响,分析了玻纤纱因捻度和捻向造成的织物单边烂边问题,阐述了玻璃纤维在经编机上生产的关键技术,总结出淀粉型玻璃纤维纱线在复合针特里科经编机上采用积极送经方式可以正常成圈编织成玻纤布。     

Novel engineering approach to optimization of thermal comfort properties of hemp containing textiles

The aim of this research was to investigate the possibilities of producing comfort hemp containing textile fabrics by assembling a pure hemp yarn with other-fibre containing yarn. The plain knitted fabrics were produced from two-assembled hemp and three variants of cotton yarns which differed in twist level, all having the same linear density. The transport properties (air permeability, water vapour permeability and thermal resistance) of the hemp-based knitted fabrics were quantitatively analysed. The results obtained demonstrated that the introduction of cotton into hemp-based textiles reduces air and water vapour permeability with the downward trend in thermal resistance. The extent to which the transport properties varied among the hemp/cotton knitted fabrics was dependent on the twist intensity of the cotton yarns. Therefore, the yarn assembling technique is an effective way not only to combine different fibre properties but to take advantage of intrinsic properties of component yarns.     

A study on thermal properties of single-jersey knitted fabrics produced from ring and compact folded yarns

This paper presents a study on the thermal properties of single-jersey knitted fabrics manufactured using ring, compact and ring/compact folded yarns. The variations in thermal properties depending on the yarn twist and traveller weight of folded yarn single-jersey knits were discussed. It was found that the thermal resistance of knitted fabrics generally increases as the traveller weight decreases, and also water vapour permeability reduces as the traveller weight decreases. The water vapour permeability and air permeability of knitted fabrics increase as the twist increases. The thermal conductivity of knitted fabrics decreases as the twist increases. The air permeability and water vapour permeability values were higher for compact folded yarn fabrics as compared to those values of ring and ring/compact folded yarn fabrics. It is observed that yarn twist and traveller weight have affected different thermal properties of single-jersey folded yarn fabrics.     

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.     

Study on effect of blend ratio on thermal comfort properties of cotton/nylon-blended fabrics with high-performance Kermel fibre

This study presents the thermal comfort properties of woven fabrics made of Kermel, cotton/nylon and cotton/nylon /Kermel-blended yarns. Our aim in this study is to combine the high comfort properties of cotton/nylon fibres with high thermal protective properties of Kermel fibre in different woven fabrics. Thus, Kermel (100%), cotton/nylon (50:50) and four blends of the 50% cotton fibres with nylon and Kermel (40:10, 30:20, 20:30 and 10:40) were spun on a ring-spinning frame and twisted into two-folded yarns with the same yarn count of 30/2(Ne) and twist level of 560 TPM. Using the produced yarns, woven fabrics with identical characteristic and structure were also produced. Then, the thermal comfort and physical properties of fabrics were studied in terms of fabric porosity, thermal resistance, thermal conductivity, water vapour resistance and air permeability. The results show that the porosity, air permeability and thermal resistance increase with Kermel fibre blend ratio. Conversely, the water vapour resistance decreases with increase of Kermel fibre blend ratio up to 40%, while 100% Kermel-woven fabric exhibits a higher water vapour resistance value. Nevertheless, the thermal conductivity of cotton/nylon-blended Kermel woven fabric is unchanged with increase of Kermel fibre blend ratio up to 40%, whereas at 100% Kermel fibre blend ratio, the lowest thermal conductivity is obtained. The obtained results implied that woven fabric produced from cotton/nylon (50/10) blended with 40% Kermel fibre resulted in proper thermal comfort properties.     

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.     

柔洁纺粘胶强捻纱及其织物性能

为更好地探究柔洁纺技术对粘胶强捻纱质量和其机织物服用性能的影响,对相同工艺参数下粘胶强捻柔洁纺纱线与环锭纺纱线的均匀度、毛羽、单纱强力、捻缩率和表观结构进行测试对比,同时分析了相同规格柔洁纺和环锭纺粘胶强捻纱织物的强伸性、顶破性能、撕破性能、透气透湿性、吸湿性、柔软性和抗起毛起球性能。结果表明:柔洁纺粘胶强捻纱的毛羽少,条干均匀,强力高,捻缩率低;相比环锭纺粘胶强捻纱织物,柔洁纺粘胶强捻纱机织物的强伸性、顶破性能、撕破性能、透气透湿性、柔软性和抗起毛起球性显著提高,但吸湿性有所降低;柔洁纺粘胶强捻纱具有柔顺、整洁、牢固等特点,其机织物的综合服用性能优于环锭纺。     

21—STT YARNS: TECHNOLOGICAL ASPECTS OF TWISTED SELF-TWIST YARNS

The STT system is one in which unidirectional twist is added to self-twist yarns to produce two-ply weaving yarns. The added twist required for the elimination of fabric patterning due to cyclic twist variation in the yarn has been determined and has been expressed in terms of the amount of self-twist in the yarn. Fabrics woven from STT yarns have been evaluated, and the dependence of fabric properties on initial self-twist and on added-twist levels has been investigated. This has resulted in recommendations for the spinning and twisting of STT yarns for use in making high-quality worsted fabrics.     

全真丝纬向弹力机织物的设计与分析

全真丝纬向弹力机织物的弹力主要利用强捻纬线的捻度释放来形成。只要将经纬紧度、经纬密度、织物组织、丝线排列方式及工艺合理配置，均可形成较为理想的纬向弹力织物。对试织的单层和双层多风格弹力绸的测试表明，设计织物的弹力均能达到中低弹水平。     

Acoustic performance of woven fabrics in relation to structural parameters and air permeability

This work deals with the study of the acoustic characteristics of woven fabrics in relation to fabric structural parameters and air permeability. In order to achieve the objectives of the research, sound absorption coefficient of woven fabric samples was determined via impedance tube method. Samples with various pick densities and yarn twist were used. The effect of fabric thickness was analyzed using three and six layered test samples. Results showed that, while for all samples the minimum values of sound absorption were observed at frequency bands of 250 and 2000?Hz, the maximum sound absorption occurred at the frequency of 1000?Hz. Results also indicated that fabrics woven at pick density of 30?thread/cm exhibited higher sound absorption than fabrics woven at other pick densities. It was found that, noise reduction coefficient of three and six layered samples, woven at low pick densities showed significant increases in comparison to those woven at high pick densities. It was also established that samples woven with lower weft yarn twist absorb sound wave more efficiently. It was concluded that fabric air permeability can be used as a criterion of sound absorption behavior of woven fabrics.     

捻向配置对尺寸稳定性的影响

利用16．2tex的S捻和Z捻棉纱线,通过改变7种平纹织物中经纱和纬纱的配置及纱线S捻和Z捻的配置,研究了捻向和捻度松弛对尺寸稳定性的影响。结果表明经纱Z捻、纬纱S捻配合时,织物的收缩率比其他捻向纱线配合时要小。     

经向T结构预制体成型关键技术

为解决采用传统的"压扁-还原"的机织方法制备三维纺织品预制体成型的局限性问题,通过深入研究织造连续性、整体性T结构预制体的成型技术,采用以正交组织为基础,通过经纱接结绑定,以机织的方法织造梁高与底面厚度相等且一次成型的T结构三维机织物。对织造工艺进行优化改进,织造了接结纱跨越不同的纬纱列数的2种T结构三维机织物,测量了不同区域的尺寸。结果表明:1个完整组织循环中,为使跨越底面区域的浮线下沉且满足织造尺寸要求,底面区域纱线数约是总纱数的一半;当纬纱跨越2个纬纱列时,织物表面的平整度和成型性更好。     

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.     

The functionality of woven fabric from air-jet yarn from the mixture of CO/PA and CO/PES fibres in the weft direction

The purpose of presented research is to find out the influence of air-jet yarn from the mixture of CO/PA (50/50) and CO/PES (67/33) fibres on functionality of woven fabric in the plain weave.The first part of the study is directed to the mechanical and physical properties of air-jet yarns (16.7 tex) from CO/PA and CO/PES fibres, while the second part of the study focuses on permeability properties of fabrics with air-jet yarns in the weft. The results show that air-jet yarn in the weft direction influences on the water vapor transmission and thermal conduction increase and air permeability decrease.Incorporation of air-jet yarn in the weft direction also improves breaking extension level.The results of presented research also show that the incorporation of air-jet yarn in the weft has statistical important influence on thermal conduction, water-vapor and air permeability changes.     

Investigation of electrical,electromagnetic shielding,and usage properties of woven fabrics made from different hybrid yarns containing stainless steel wires

This paper reports the results of a detailed study about specific properties of hybrid yarns and woven fabrics containing those yarns. For this aim, the fabrication procedures and physical properties of acrylic/stainless steel (SS) and cotton/acrylic/SS ply yarns were presented, and then, relations between those and electrical, electromagnetic shielding effectiveness (EMSE) and some usage properties of woven hybrid fabrics made from those with different constructions were investigated. EMSE of plain and twill fabrics were evaluated against radiating electromagnetic wave spectrum over a frequency 0–3000?MHz. A comparison of physical properties of yarns regarding wire diameter and the use properties of fabrics regarding weave type, wire diameter, and yarn type measured were presented. The functional textile products of complex applications can be achieved with low cost, easily since those yarns and fabrics were produced on conventional textile manufacturing machines with small modifications. The present study indicated that use of SS wire-based yarns in fabrics significantly increased the air permeability, pilling resistance, thermal resistance, and the flexural rigidity of hybrid fabrics. The plain weave fabrics exhibited higher EMSE values over 20?dB in higher frequencies and higher thermal absorbtivity values compared to twill fabrics.