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.     

Packing of micro-porous yarns: Part I. Optimization of yarn characteristics

The present paper deals with the factors affecting the packing of a micro-porous yarn, namely proportion of PVA fibre content, yarn twist multiplier (TM) and spindle speed at ring frame, and with their combined effect on various properties of the yarn. The micro-pores within the structure of the yarn have been created by dissolving the PVA fibres using washing treatment in hot water. A three-variable factorial design technique proposed by Box and Behnken is used to investigate the combined interaction effect of the above variables on the properties of the yarn. The present experiment variables, namely proportion of PVA fibre, yarn twist multiplier (TM) and spindle speed, were found to have significant impact on various properties of yarns before and after wash. For yarns before wash, the specific volume reduces with the increase in the PVA content, yarn twist and spindle speed. In the case of yarns after wash, there is reduction in the yarn specific volume with the increase in TM and spindle speed, but with the increase in the PVA percentage the yarn specific volume increases. The tenacity of yarns before wash increases with the increase in the PVA content, but for yarns after wash, the proportion of PVA content has comparatively less influence. The compressibility of yarns before wash reduces with the increase in the PVA content, but a reverse trend is observed in the case of yarns after wash. The design variables were optimized for all the yarn properties by using the response surface equations.     

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.     

Permeability properties of single jersey fabrics made of hollow yarns

In this work effect of using hollow yarns on the permeability properties of the single jersey knitted fabrics were studied. Firstly yarns were produced by ring spinning machine using cotton, viscose and acrylic fibres in the mantle and water soluble polyvinyl alcohol (PVA) fibre in the core. Single jersey fabrics were knitted and PVA core was removed subsequently by washing process to create hollow yarn. Weight, air permeability and water transmission rate properties of fabrics were measured before and after washing and compared with reference fabrics. Due to the removal of PVA fibres from the yarn core after washing treatment, air permeability and water vapour transmission rate of the all kind of single jersey fabrics which were produced with hollow yarns increased as well as weight of the fabrics decreased which will cause more comfort during any exercise. It was also found that mantle fibre type and PVA ratio have significant effect on the fabric properties.     

用Dref 3摩擦纺多组分纬纱织造的织物的风格特征

研究分析了3种用Dref3摩擦纺多组分纬纱织造的平纹织物的风格特征。3种不同的纬纱是：芯皮均为粘纤;水溶性PVA作皮,粘胶无捻纱条作芯;PVA无捻纱条作芯,粘纤作皮。3种纱均在Dref3型摩擦纺机上按芯皮50／50比例纺成,经纱统一采用2合股纯棉纱线。将3种纱分别织成织物,然后用热水将PVA溶解去除。织物性能的测定结果：织物性能与组成织物的纱组分性能并不一致。无捻芯纱(溶掉PVA表皮)织物具有较高的拉伸强力、撕裂强力、折皱回复性和耐磨性;而空心纱(溶掉PVA作芯)织物具有丰满、蓬松的结构和良好的耐压缩性能。     

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.     

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.     

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.     

聚酯长丝/棉复合纱斜纹织物的保形性及服用性能

为研究聚酯(PET)长丝/棉复合纱斜纹织物的保形性及服用性能,利用PET长丝与纯棉纱开发了3种线密度为9.8 tex的纱线,并以二上二下斜纹组织织造了4种织物。对织物进行了折皱回复性、免烫性、尺寸稳定性、悬垂性等保形性能,强伸性、拉伸弹性、顶破性等抗变形性测试,以及手感风格、透湿性、透气性等服用性能测试。对比分析了纯棉纱织物与复合纱织物的保形性与服用性能。结果表明:PET长丝/棉复合纱可改善纯棉织物的折皱回复性、悬垂性,提高免烫等级,同时又不影响织物的服用性能;包芯纱织物比包缠纱织物有更好的保形性,更高的免烫等级,是免烫衬衫面料的理想选择。     

黄麻混织针织物的设计与开发

本研究针对黄麻纱线粗硬、毛羽较多,弹性低等特点,对纱线毛羽、细度及强度进行测试并选择适合的棉及涤纶纱线进行混合。将黄麻与棉及涤纶纱线经过合股上蜡处理后,在针织横机上设计并编织罗纹、移圈、圆筒等不同组织和结构的黄麻混织织物及产品。通过对黄麻混织织物的耐磨性、透气性、抗起毛起球等性能进行测试与分析,结果表明麻涤1罗纹织物耐磨性、耐起毛起球性最好,而麻棉4为单面圆筒织物线圈密度最小,透气性能最优;麻棉2由于具有移圈及凹凸效果,透气性能次之,耐磨性稍差。所织织物适合制作具有田园风格的家居类装饰物,从而开发黄麻纤维更广泛的应用领域。     

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.     

The effect of core-sheath proportion on the characteristics of fabrics produced with hollow yarns: part II comfort and mechanical properties

The study aims to investigate the effect of hollow yarn structure and the sheath-core proportion of hollow yarns on the permeability properties of the knitted fabrics. In order to accomplish this, core yarns in the yarn count of 59 tex were produced by using cotton, viscose, wool, and polyester fibers in the sheath and different ratios of polyvinyl alcohol (PVA) in the core. After completion of yarn production on ring spinning frame, the yarns in the form of packages were used to produce plain knitted fabrics. Fabrics were then divided into two groups, one of which was washed during a time period in order to remove PVA from the core to obtain hollow yarn structure. Air and water permeability, and wicking properties of the knitted fabrics were measured before and after washing processes. Mechanical properties such as pilling and bursting strength of the fabrics were also examined. The results show that washing process and PVA proportion used to produce core spun yarns have a significant effect on the permeability and mechanical properties of the fabrics.     

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.     

Comfort properties of bamboo/cotton blended knitted fabrics produced from rotor spun yarns

The comfort characteristics of bamboo/cotton-blended knitted fabrics made from rotor-spun yarns were studied in this research work. Five different blend proportions namely 100% bamboo, 100% cotton, 50:50 cotton:bamboo, 70:30 cotton:bamboo and 30:70 cotton:bamboo were used to produce rotor-spun yarns of 30^sNe_c. The yarn samples developed out of these different blend proportions were evaluated for yarn strength and elongation, yarn unevenness, yarn imperfections and used to produce single-jersey-knitted fabrics. All the fabric samples were dyed and finished. Fabric samples were evaluated for geometrical properties such as course/inch, wales/inch, stitch density and thickness apart from measuring comfort properties such as airpermeability, thermal conductivity, thermal resistance and water vapour permeability. The results indicated that 50/50 bamboo/cotton-blended knits have comparable fabric quality in terms of comfort properties with respect to 100% bamboo fabrics.     

Comparison of thermal comfort properties of single jersey fabrics produced by hollow yarns with different hollowness ratio

In this study, the thermal comfort properties of single jersey fabrics produced by conventional and hollow cotton yarns with different hollowness ratio have been investigated and compared. For this purpose, thermal conductivity, thermal resistance, thermal absorptivity, air permeability and water vapour permeability of core spun, hollow and conventional yarn fabrics were measured and evaluated statistically. It was observed that thermal comfort properties of single jersey fabrics were affected by the yarn structure and the fibre distribution within the yarn. The results showed that hollow yarn fabrics had better thermal comfort properties than that of conventional yarn fabrics. In hollow yarns, as the hollowness ratio increases, air permeability and thermal conductivity of single jersey fabrics decrease but thermal resistance, thermal absorptivity and water vapour permeability increase. Statistical analysis also indicated that the differences between properties of hollow yarn fabrics and conventional yarn fabrics were significant. Furthermore, the yarn hollowness ratio significantly affects thermal comfort properties of single jersey fabrics.     

Modelling to predict thermophysiological properties of hollow/microporous yarn fabrics

Hollow/microporous yarn spinning is a technique used to increase the bulk of yarn without increasing its weight. Hollowness in the cotton yarns has been introduced by various methods and techniques. Empirical models have been developed to predict the thermophysiological properties through structural parameters. Based on standardized multiple linear regression models, fabric’s structural parameters are related with thermophysiological properties of hollow yarn fabrics. Three basic parameters i.e. yarns packing density, inter-yarn porosity and fabric thickness have been found to relate strongly with fabric thermophysiological properties except water vapour permeability.     

Thermo-physiological comfort properties of double-face knitted fabrics made from different types of polyester yarns and cotton yarn

Double-face knitted fabrics with hydrophobic inner and hydrophilic outer layers are characterised by their advantageous thermo-physiological comfort property that facilitates the transport of sweat from skin to outer fabric layer where it can be evaporated easily. In this study, for the production of double-face knitted fabrics, cotton yarn as hydrophilic yarn type and five different polyester filament yarns consisting of standard polyester, hollow polyester, micro polyester, textured polyester and textured micro polyester as hydrophobic yarn type were used. In order to determine the thermo-physiological comfort properties of the fabrics, air permeability, water vapour permeability, thermal conductivity, thermal resistance and overall moisture management capacity were measured. The results were comparatively analysed using statistical methods. The experimental results demonstrated that the polyester-type yarns and the combinations of them with the cotton yarn in fabric layers affected the thermo-physiological comfort properties significantly. The fabrics with polyester-type inner face and cotton outer face showed the best moisture transmission properties.     

Wicking and drying properties of conventional ring- and vortex-spun cotton yarns and fabrics

This study investigated the vertical wicking, water absorption and drying properties of vortex- and ring-spun combed cotton yarns and knitted fabrics comparatively. The yarns were produced in three different counts as 30 Ne, 40 Ne and 50 Ne. The experimental results revealed that vortex-spun yarns had lower yarn and fabric wicking and water absorption values than ring-spun yarns. In addition, it was observed that yarn type did not have a significant impact on the drying time of the fabrics.     

芯丝种类对织物抗皱性及抗变形性的影响

文章采用全聚纺纺纱方式生产了JC/PET、JC/PTT、JC/SPH、JC/T400四种包芯纱和一种纯棉纱,利用这五种纱线织造了规格相同的五种机织物。分别利用客观与主观评价法,评价织物的抗皱性及平整度等级,同时测试了织物的拉伸弹性回复率,以研究芯丝种类对织物抗皱性及抗变形性的影响。结果表明:芯丝的加入可以改善纯棉织物的平整度;长丝的初始模量、弹性影响织物的抗皱等级,SPH的初始模量最高、T400的弹性回复性最好,因此JC/SPH和JC/T400包芯纱织物抗皱等级最高,可以达到3. 5级;且这两种长丝的表面均有沟槽,截面为异形,起到毛细管作用,其织物具有较好的吸湿排汗作用,是开发高保形免烫衬衫面料的理想选择。     

Ultraviolet radiation protection by cotton fabrics: role of porous yarn structure,fabric thickness and pore size

The effect of porous yarn structure on ultraviolet (UV) radiation protection by cotton fabric has been investigated. Fabrics with porous yarn structure showed higher ultraviolet protection factor (UPF) in comparison with that of fabrics woven from equivalent normal yarns. Fabric samples having different thickness and individual pore size, at same cover %, were produced by adjusting yarn count and thread density. UPF of UV absorber treated cotton fabrics increased continuously with decreasing thickness and reducing individual pore size when the fabric cover was kept constant at relatively higher levels (93 and 96%). For UV absorber treated cotton fabrics, individual pore size is the dominating factor for determining the UPF.