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.     

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.     

摩擦空心纱的结构特点和拉伸性能

对以PVA短纤维纱为芯纱,棉纤维为外包纤维的摩擦包芯纱,通过水煮处理去除可水溶的PVA芯纱后,制得摩擦空心纱。对摩擦空心纱以及具有加强芯纱的摩擦空心纱的结构特点和拉伸性能进行了试验研究。摩擦空心纱的结构特点是空心部分位于纱线的中心,溶芯后纱线结构膨松,直径增大。试验结果表明溶芯后摩擦空心纱的强力很低,其原因为去除了高强力的芯纱,溶芯后纱线膨胀引起纤维间抱合力减小;用涤纶长丝作为加强芯纱可以显著提高摩擦空心纱的强力。     

长丝喂入位置对赛络纺包芯纱结构与性能影响

针对赛络纺包芯纱纺制过程中,长丝不同喂入位置对纱线结构和性能的影响,分别纺制了涤纶长丝在左侧粗纱须条中心、两粗纱须条中间、右侧粗纱须条中心3种结构的短纤/长丝赛络纺包芯纱。对比分析了纱线截面、成纱质量、耐磨性能、拉伸断裂过程和纱线退捻特征。结果表明:3种包芯纱中涤纶长丝均在纱线中心附近,无明显漏丝,条干均匀,毛羽较少;左侧粗纱须条中心喂入纱线拉伸断裂曲线有多峰特征,两粗纱中间喂入纱线拉伸断裂曲线有密集波动特征;右侧粗纱须条中心喂入纱线初始弹性模量最高,拉伸断裂特征为阶梯性断裂,退捻最困难,且在退捻过程中部分纱段被反向加捻,纱线结构最稳定,耐磨性好,纱线强力最高。     

羊绒/羊毛/涤纶复合纺及成纱拉伸性能分析

选择羊绒、羊毛和涤纶长丝在传统的环锭纺系统上进行三组分复合纺纱。通过改变三组分的喂入位置、喂入张力来获得不同结构和风格的纱线。试纺了不同捻度和混纺比的3种复合结构纱,即股线、包芯和包缠结构纱,分析了其拉伸性能。纺纱实验和测量结果表明:通过复合改善了羊绒纱的强度;纱线拉伸性能与混纺比、捻度、纱线结构之间存在相关;随着捻度的增加,3种结构复合纱的拉伸性能均符合经典临界捻度理论;复合纱的力学性能因结构不同而不同,股线结构纱拉伸性能最好,包芯结构纱次之,包缠结构纱拉伸性能则最差。     

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.     

聚乙烯醇对芳纶复合纱聚苯胺导电层耐久性影响

为提高聚苯胺导电层与基材之间的黏结牢度,以聚乙烯醇为共混高聚物,通过连续原位聚合法在对位芳纶纱线表面形成聚乙烯醇/聚苯胺导电层,制备得到芳纶/聚苯胺/聚乙烯醇复合导电纱。分析了导电纱的结构与性能,并研究了聚乙烯醇对聚苯胺导电层耐水洗和耐磨性的影响。结果表明:适量添加聚乙烯醇有助于提高导电纱导电层的结构规整性及电导率,随着聚乙烯醇质量分数的提高,导电纱的电导率呈先上升后下降的趋势,当聚乙烯醇占苯胺的质量分数为4.30%时,制得的复合导电纱线的电导率最高,达到(1.120±0.198) S/cm;聚乙烯醇的添加和质量分数的提高,有助于聚苯胺导电层耐水洗性及在较小外力作用下的耐磨性的提高。     

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。     

亚麻/有色涤纶长丝包缠复合纱的外观与性能

为探讨亚麻/有色涤纶丝包缠复合纱的混色特征,以及包缠捻度对混色效果及复合纱性能的影响,以有色涤纶网络丝为外包缠纱,亚麻漂白纱为芯纱,纺制不同颜色和捻度的包缠复合纱;分析了复合纱的外观特征,测试了纱线的拉伸性能、条干、纱疵和毛羽。结果表明:复合纱具有麻彩外观,芯纱粗节处包缠捻度大呈色浅,细节处捻度小呈色深,复合纱沿长度方向有弱段彩效果;改变外包缠纱的包缠捻度,可改变复合纱的混色质地和颜色深度;包缠复合可提高亚麻纱的断裂强力和断裂伸长率,改善纱线条干,减少纱疵和毛羽;包缠复合纱受到拉伸作用会发生芯纱和外包缠纱不同时断裂现象,但随着包缠捻度的增大,不同时断裂的发生比率会降低。     

基于分数阶模型的纱线蠕变性能模拟与预测

针对现有纱线拉伸力学模型描述不准确问题,以分数阶微积分模型对纱线拉伸行为进行分析。首先,引入分数阶微积分理论改进的黏壶模型建立了分数阶纱线蠕变模型,使用XL-2型纱线强伸度仪对不同线密度及不同张力纱线进行蠕变实验,获得纱线蠕变的全过程曲线。通过对不同线密度下的试验曲线进行回归分析得到了模型参数以及蠕变模型参数与施加张力大小的变化关系。最后,利用不同模型对不同张力的纱线蠕变曲线进行拟合和预测。结果表明：分数阶纱线蠕变模型,相比于三元件模型、整数阶模型和Burgers模型,具有结构简单、参数少的特点,并且对纱线蠕变的拟合和预测也具备较高的精度。     

喷气涡流纺工艺对粘胶/涤纶包芯纱性能的影响

为获得更高强力的喷气涡流纺纱线,通过引入涤纶长丝制备喷气涡流纺粘胶/涤纶包芯纱。采用统计分析等方法研究了芯丝线密度、纺纱速度对喷气涡流纺粘胶/涤纶包芯纱强伸性、条干不匀和毛羽的影响规律,同时对比分析了不同纺纱条件下包芯纱的结构外观。研究结果表明：芯丝线密度、纺纱速度对喷气涡流纺粘胶/涤纶包芯纱各性能响应值有不同程度的影响;纺纱速度过高或过低均不利于包芯纱成纱的强伸性提高和条干均匀性改善,纺纱速度的增加会使毛羽H值增大;在一定范围内,增加芯丝线密度有利于包芯纱强伸性的提高,随芯丝线密度的增加,包芯纱毛羽H值减小;此外,选用较大的芯丝线密度和较高的纺纱速度时,纺制的包芯纱芯丝外露现象越明显。     

不锈钢短纤维/棉包覆氨纶纱的弹性与电学性能

为开发兼具弹性和导电性能的电磁功能纱线,以氨纶为芯丝、外包不锈钢短纤维/棉混纺纱,研制系列弹性不锈钢短纤维/棉包覆氨纶纱。在Instron 5566万能试验机上,结合万用表,获得弹性纱线的应力-应变、应变-电阻以及定伸长弹性回复曲线,研究纱线在不同拉伸状态下的电学性能。结果表明:不锈钢短纤维/棉包覆氨纶芯丝的纱线,存在氨纶芯丝的断裂现象,将不锈钢短纤维/棉包覆氨纶芯丝的纱线直接与氨纶丝或氨纶/棉包芯纱直接并合的方式,赋予纱线弹性;随着不锈钢短纤维含量的增加,弹性纱线的弹性伸长和回复性能都降低,塑性变形增加;随着弹性纱线应变的增加,其电阻先增加后降低。     

A comparative study on properties of dual-core yarns

Core-spun yarns containing Spandex have been widely used for the production of elastic textile materials. However, it has been encountered various problems not only during the usage but also during textile processes due to its high recovery property. In order to solve these problems, multicomponent core-spun yarns called as dual-core (DC) yarns, have been developed. DC yarns can be produced on the modified ring spinning machine in two different ways. In the first method, previously combined two core yarns are fed simultaneously, whereas in the second method, two core yarns are given separately into the centre of sheath fibre bundle. In present study, it was aimed to research the effect of these production methods on yarn features. Polyester and Spandex core components and cotton wrapping fibres were brought together in both two ways and the properties of multicomponent core-spun yarns were compared with cotton ring counterparts for three different yarn counts.     

长丝纱断丝性测试与表征

为探讨由多根单丝组成的长丝纱在受到拉伸作用时,发生单丝断裂的性能及其测试与表征方法,对一种锦纶6 无捻长丝纱进行了拉伸试验,获取了断丝发生的典型拉伸断裂曲线;通过分析该断裂曲线特征,建立了基于断丝频次和应力条件的表征长丝纱断丝性的指标体系;对3 种不同长丝纱进行了拉伸不同验,分别计算出表征长丝纱断丝性的指标并对其进行分析。结果表明：长丝纱在拉伸至断裂过程中,部分试样会发生单丝断裂现象,且可能不只发生1 次;每次单丝断裂均会在拉伸断裂曲线上形成一个锯齿状波形;长丝纱的断丝性可用一定次数拉伸试验中断丝发生的频次类指标和断丝发生时的应力类指标进行表征,发生第1 次断丝时的应力值越低,断丝频次越高,表明长丝纱越易发生断丝。     

锦纶/塑料光纤包覆纱的纺制及性能分析

为改善塑料光纤易从织物中滑脱的问题,以27.8 tex塑料光纤作为芯丝、不同线密度的锦纶丝作为外包丝,制备4种锦纶/塑料光纤包覆纱,分析锦纶/塑料光纤包覆纱的拉伸性能、耐磨性能及透光性能。结果表明:包覆工艺未对塑料光纤表面造成影响;随着外包锦纶丝线密度的增加,锦纶/塑料光纤包覆纱的断裂强力逐渐增大,断裂伸长率基本稳定在26.26%~31.72%。锦纶(15.6 tex)/塑料光纤包覆纱的拉伸性能和耐磨性能最好。锦纶/塑料光纤包覆纱的透明度随外包锦纶丝线密度的增加而增加,锦纶(4.4 tex)/塑料光纤包覆纱的透光性能最好。     

低扭矩环锭纺纱原理及其单纱的结构和性能

本文主要回顾了低扭矩环锭纺纱技术的发展。通过讨论其纺纱三角区的特点,利用高速摄影技术对纺纱区捻度和张力分布的观察分析,系统地介绍了低扭矩纱的成纱原理。此外,结合示踪纤维技术,利用纱线结构连续测量分析系统对低扭矩环锭单纱和传统环锭单纱的内部结构进行分析,揭示了低扭矩纱独特的结构特点,如非同轴异形螺旋线结构,纤维片段局部反转现象等。这些特点解释了低扭矩纱及其织物具有优良物理性能的原因。同时,通过多个生产厂家提供的测试数据,对比分析了几代低扭矩环锭纱与传统环锭纱及其织物的物理性能,结果表明低扭矩环锭纱具有低捻高强、低残余扭矩和毛羽少等特点,其针织物经多次水洗后歪斜变形小和手感好,机织物具有较好的撕裂强力,断裂强力和耐磨擦性。最新一代低扭矩环锭纺纱技术显著地改善了高支纯棉纱的物理性能。     

棉型中空纱强度与PVA含量关系的研究

采用水溶性维纶纱线作纱芯,棉作外包纤维,在传统的环锭纺纱机上纺制棉包芯纱,溶去芯纱,制得棉型中空纱。并对棉型中空纱的强力与PVA含量的关系进行了试验、分析与讨论。其结果对中空纱的纺制有指导意义。     

数码转杯纺成纱原理及其纱线特点

为开发新颖的纱线品种,提高纱线生产效率,提出数码转杯纺成纱方法并介绍其原理,对成纱色彩特点进行研究。数码转杯纺采用３ 组分异步喂入的方式,纤维通过分梳辊的梳理和混合,在转杯内离心力作用下再次混合并凝聚成须条,经加捻后成纱,再由引纱罗拉导出形成特种纱线。该工艺过程可随机调控转杯纺成纱的线密度及混纺比,生产多种混合均匀的混色纱和混纺纱品种。分别纺制了混色纱、变色纱、段彩纱、竹节纱、彩节纱和双变纱等典型数码纱,并对其色彩特点进行分析,总体来说数码转杯纱不同颜色的单纤维混合均匀,纱线颜色柔和。     

无捻纱退维时间的分析

无捻纱的退维工艺是织制无捻纱织物的关键工艺,退维过程的控制一直是困扰水溶性维纶伴纺与混纺产品开发的难点。为准确测试无捻纱退维的时间,采用纱线强力测试法和称重法对无捻纱的退维时间进行验证测试,2种测试方法基本相符,30 min左右合股纱线上的维纶能够全部溶解,为实际生产中无捻纱织物退维时间的确定提供了可靠的依据。     

A study on the suitability of which yarn number to use for recycle polyester fiber

Recycling and reuse of materials is not new to the textile and apparel industry. Recycling refers to the breakdown of product into its raw materials in order for the raw material to be reclaimed and used in new products. The aim of the study is that the examining the usage of recycle polyester fiber (rPET) in different yarn count and blend ratio and so to determine which count and blend ratio is more suitable for rPET usage. For this aim, 24 yarns containing recycle polyester fiber, virgin polyester fiber and viscose fiber as raw material were obtained in different yarn counts which are Ne 10, Ne 20, Ne 30 and Ne 40, and in different blend ratios. Yarn diameter, density, shape (roundness), unevenness, imperfection, hairiness, and yarn tensile tests were applied to the obtained yarns. The findings obtained by experimental and statistical study show that rPET fiber has usually negative effects on the yarn properties in especially fine yarns due to physical and chemical deterioration caused by contaminants of during re-processing of recycle polyester fiber. Based on the findings it is revealed that the values of unevenness, imperfection, and density increase whereas the values of diameter, hairiness, and tensile decrease from coarse yarns to fine yarns. As a conclusion it is possible to say that rPET fiber is suitable for thick yarns which are especially Ne 10 and Ne 20 as pure and in all blend ratios, and rPET fiber is suitable if it is used in lower ratios than 65% for Ne 30 yarns, whereas it is suitable if it is used in lower ratios than 35% for Ne 40 yarns.