Influence of stabilization and short-term relaxation to compression generated by stocking welt

Abstract

This research was carried out to investigate the influence of yarns and knitting parameters, stabilization, and relaxation processes on compression properties of knitted fabrics, used for stocking welt or other compression products. It is well-known that there is a high correlation between the mechanical properties of the fabric and its generated pressure. Also, it is proved that generated compression values decrease during the time they are being worn. In this research, it was found that course and wale density of knitted fabric, as well as tensile force values, increased after the stabilization process. Moreover, increases of linear density of core yarn (PU) of elastomeric yarn do not have direct linear influence to its generated tensile force. The results of short-term stress relaxation tests (300?sec) showed that the major alteration of the generated compression values appears during the first 100?sec period of relaxation process.     

A relationship between dry-relaxed warp-knitted fabric structure and curling distance

This study provides us information about relationship between curling and knitted structure and density of two-guide bar warp-knitted fabrics. Five standard warp-knitted fabrics are produced with three densities (Tricot, Locknit, three-needle Satin, Reveres Locknit and three-needle Sharkskin). Certain cut lengths of sample fabrics in both wale and course direction are analyzed through image processing to define curling value. A mechanical model, a function of fabric structure and yarn parameters, is also suggested to predict the curling force. The results of experimental and theoretical results show a greater curling value for course-wise cut in comparison to that of wale-wise in all warp-knitted structures and densities. The lowest curling value is found for three-needle Sharkskin structure in both directions and all densities.     

经编针织物双向拉伸性能研究

测试了5种经编针织物的双向拉伸性能,考察了拉伸方向、拉伸速率及织物结构对拉伸性能的影响。当织物结构相同且一个方向固定、另一个方向拉伸时,横向拉伸的断裂强力与断裂伸长大于纵向拉伸的。随着拉伸速率提高,织物的断裂强力与断裂伸长先增大后减小。当织物组织结构与参数相近时,双向拉伸的各项指标相差不大。单梳经绒织物的断裂伸长比经绒平、经平绒、菱形及四角网孔4种双梳织物的大。     

Effect of structural parameters on the cut resistance of para-aramid and ultra-high molecular weight polyethylene weft knitted fabrics

Abstract

In this study, the cut resistance of pure and hybrid knitted para-aramid and ultra-high molecular weight polyethylene fabrics with different structural parameters were measured according to ASTM F1790. The results showed that there is an optimum value for stitch density in which the cut resistance is maximized. The highest and the lowest cut resistance was observed in the courses and the wales directions, respectively. The interposed values were obtained in the bias direction. Coating with casting polyurethane resin increased the cut resistance of the fabrics. Para-aramid samples had higher cut resistance than UHMWPE samples in higher stitch densities, and hybrid samples showed a higher cut resistance than the pure ones, due to some of their structural features.     

An analysis of the bending rigidity of warp-knitted fabrics: a comparison of experimental results to a mechanical model

This study focuses on the bending rigidity of warp-knitted fabrics as a function of knit structure (underlaps length), density (wale and course spacing) and yarn bending properties. Seven standard warp-knitted fabrics are produced with three different densities (Tricot, Locknit, three and four needles Satin, Reveres Locknit, three and four needles Sharkskin). The bending rigidity of the fabrics is measured using a Kawabata evaluation system and an automatic cyclic bending tester. Results show that the bending rigidity increases for the fabrics with a higher density and underlaps length of the front and back guide bars. In addition, a new mechanical model for the bending behaviour of warp-knitted fabrics using an energy method is presented. In this model, the knitted loop structure is assumed to consist of a series of straight and skew yarns simulating legs and underlaps while considering a rigid region lying in the direction of bending. Experimental results show that there is a reasonable agreement between the calculated and measured values for both wale and course directions.     

竹原纤维/丙纶纬编针织复合材料的制备及拉伸性能研究

以竹原纤维纱线和丙纶长丝为原料,在电脑横机上织造了平针、罗纹和罗纹空气层3种纬编针织物,再用热压成型方法将其制成复合材料,并进行拉伸性能测试。实验结果表明:3种复合材料的拉伸强度和弹性模量都是纵行方向大于横列方向,而断裂伸长率则相反;在3种不同的组织结构中,平针复合材料的拉伸强度和弹性模量最大,罗纹空气层复合材料次之,罗纹复合材料最小;对罗纹复合材料而言,较佳的热压温度和时间分别是175℃和10min。     

羊毛畦编针织物尺寸特性分析

通过实验的方法,研究了横机编织的罗纹、半畦编和畦编羊毛针织物的尺寸特性,对3种织物的线圈长度、纵横向水洗收缩率、纵密及横密等各尺寸特性进行了分析与比较,实验得出,由于集圈线圈的存在,半畦编和畦编针织物的尺寸特性显著不同于罗纹针织物.通过建立尺寸变化率公式,计算出畦编织物与罗纹织物尺寸参数间的关系,可用于工厂实际生产设计时参考.     

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.     

棉氨弹性添纱针织物的动态弹性性能

研究了热定型和热收缩温度对棉氨添纱针织物的动态弹性性能的影响.为了避免在研究动态弹性回复(DER)中产生的直接作用,利用动态弹性回复系数(DERR)分析在线圈横列和线圈纵行上的综合的直接动态弹性回复(DER)值.热定型温度会影响织物的DER值,但是热收缩温度却不会对其有影响.所以,对于不同组织的针织物,有必要优化其热定...     

Prediction of deformation behavior of interlock knitted fabrics in different directions using FEM method

This study undertakes to predict the deformation behavior of conventionally interlock knitted fabric using a novel geometrical model. Deformation behavior of this kind of knitted fabrics was numerically simulated in course, wale, and bias directions, using FEM method. In order to elaborate the study, high and medium tightness interlock knitted fabrics were selected and deformation of fabrics analyzed in course, wales and bias directions (0°, 45°, and 90°). Accuracy of the proposed geometrical model was investigated comparing the simulated tensile stress–strain curve to the measured one. Output data revealed that the stress–strain curve obtained from simulating method has high conformity with the experimental one.     

The Effect of Sizing on the Weavability of Cotton Yarns—Reply

An account is given of a study of the behaviour of three basic wool weft-knitted structures when subjected to ‘shear at constant length of sides’.

It was found that all the weft-knitted structures studied had a relatively low over-all shear-resistance when compared with other textile structures, such as woven and non-woven fabrics. This low over-all resistance was found to be a combination of a relatively large frictional restraint and a very low resistance once frictional slippage had started. These and other effects are discussed in terms of the geometrical changes occurring within the knitted unit cell during shearing.     

10—THE DIMENSIONAL PROPERTIES OF SOME WOOL DOUBLE-JERSEY STRUCTURES IN RELAXATION AND LAUNDERING

The dimensional behaviour of five non-jacquard wool double-jersey structures is investigated, both in relaxation (involving tumble-drying from the wet state) and in extensive laundering (Cubex washing followed by tumble-drying).

Tumble-drying for 1 hr from the wet-fabric condition only approximates to the completely relaxed state. Some felting of untreated fabrics occurs, but the effect of tumble-drying on felting is very small. Adequately shrink-resist-treated fabrics cannot be considered completely relaxed even after two consecutive tumble-drying cycles of 1-hr duration. However, in general, this technique allows sufficient fabric relaxation for subsequent dimensional changes over extensive laundering cycles of treated fabrics to be compatible with domestic machine-washable tolerances.

The felting rates of knitted wool fabrics in laundering from the ‘fully relaxed’ condition of untreated fabrics are dependent on the cover factor and independent of fabric structure. Under no circumstances, however, can untreated double-jersey fabric be practically manufactured to such tight constructions that felting can be eliminated entirely.

The linear dimensions of shrink-resist-treated fabrics in the fully laundered state are primarily dependent on the length of yarn in the structural knitted cell. In a semi-relaxed state, linear dimensions depend to a large extent on cover factor and the degree of distortion of the fabric.     

针织西服面料的挺括风格研究

为探讨针织面料在西服开发应用的要求与标准,寻找能够用于西服开发的针织面料,分别从弯曲长度、折皱回复性、悬垂性3个方面对针织面料的挺括风格进行量化分析。借助实验仪器以及数据处理得到弯曲刚度、折皱回复角、静态悬垂系数3项性能指标,以机织西服面料为参考标准,对针织面料的挺括风格进行研究分析。结果表明:6路变化罗马组织是较为适合针织面料开发西服的组织结构,其结构稳定性优于12路小提花组织以及变化间隔组织,降低纵向弯曲刚度与横向弯曲刚度的差异;织物厚度增加0.1 mm,折皱回复程度提高10%;织物密度控制在110~130线圈/(5 cm)时,悬垂程度达到机织西服面料的60%以上;6路变化罗马组织配合高织物密度能够使针织面料的挺括风格达到机织西服面料的80%。     

The use of micro-computed tomography to determine the fabric cross-sectional area and stress

Accurate measurement of the cross-sectional area of porous fabric is quite important to determine fabric strength. Many models using yarns cross-section were built to calculate the strength of woven and knitted fabrics, and the spaces between fibres in the yarns were always considered to be part of the cross-sectional area. In our previous study, using micro-computed tomography (CT) and reconstructed three-dimensional (3D) images and based on the evaluation of the pore diameter distribution across the thickness direction, a new method was established to accurately determine the fabric ‘surface’ and fabric thickness. In this study, we used this method to calculate the cross-sectional area of fabrics and the resulting fabric stress. Using a plain weave and a flat knit fabrics showed that the cross-sectional areas in warp (or wale) and weft (or course) directions of the fabrics change regularly based on fabric structures and yarns. The fabric stress, when calculations were based on the least cross-sectional area, were greater than that calculated based on the other methods, such as the stress calculated based on the Peirce yarn model, where yarns are regarded as solid cylinders. Other research and properties related to the fabric thickness and cross-sectional areas will benefit from this accurate determination.     

影响竹浆纤维针织物起毛起球性的因素

为深入分析竹浆纤维针织物起毛起球性的影响因素,根据7种竹浆纤维纬平针针织物的基本结构参数和起毛起球性的测试结果,应用灰色关联分析法对织物基本参数与起毛起球性之间的关系进行了定性和定量分析.结果显示:对起毛起球性的影响程度依次为织物的面密度、纵密、厚度、纱线线密度、氨纶含量、织物横密和竹浆纤维含量;含氨纶纯竹浆纤维针织物...     

后整理工艺对纯苎麻针织物性能的影响

针对纯苎麻针织物在穿着过程中具有强烈刺痒感的问题,简要阐述苎麻针织物刺痒感产生的原因及降低刺痒感的方法。采用剪毛－柔软剂整理、纤维素酶－柔软剂整理、柔软剂整理3种工艺对纯苎麻针织物试样进行后整理加工,并对整理后纯苎麻针织物的线圈密度、织物面密度等织物基本织物规格及纵向拉伸强力、悬垂性能、起毛起球性能、折皱回复性能及织物刺痒感进行了测试与分析。实验结果表明,后整理工艺均能降低纯苎麻针织物刺痒感,但后整理工艺会劣化纯苎麻针织物的基本性能,对拉伸强力的劣化尤为明显。对比分析3种后整理工艺发现,剪毛－柔软剂整理的复合整理能有效降低纯苎麻针织物刺痒感,是较为理想的后整理工艺,但对织物力学性能影响较大。     

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.     

针织滚边领延伸性影响因素分析

为了研究针织滚边领的拉伸性的影响因素,选用六种不同性能的针织面料,通过实验研究不同的面料性能、不同的缝纫条件对滚边领的拉伸性的影响。结果表明：面料性能对滚边领的拉伸性的影响较大;滚边领拉伸性与横密、纵密、断裂伸长率呈正相关,横密、纵密、断裂伸长率越大,滚边领拉伸性越好;滚边领拉伸性与纱线线密度呈负相关,线密度越小,滚边领拉伸性越好;同种面料、同一针距密度下,采用单针滚边制作的滚边领要比采用双针滚边制作的拉伸性要好;同种面料、同机针数制作的滚边领,随着针距变密,其拉伸性也越好。     

机织针织复合织物的拉伸性能

根据新型机织针织复合织物的结构特点,选用玻璃纤维作经纱、纬纱和高强涤纶作针织纱编织了这种织物.为提供这种新型织物的应用依据,测试织物的横向、纵向拉伸性能,分析比较拉伸负荷和位移特征曲线.研究表明:机织针织复合织物在拉伸过程中,先由其中的机织结构在较低的伸长下承担较高的负荷,直至机织结构破坏,然后由针织结构在较高的伸长下...     

Influence of process variables on antimicrobial properties of cotton knitted fabrics

ABSTRACT

This work discusses the influence of process variables on antimicrobial properties of cotton single jersey knitted fabrics. The antimicrobial process variables are optimized based on the Box-Benken experimental design using design-expert software 8.0 to predict the optimum process parameter for achieving the required level of antimicrobial properties. The effects of process parameters such as yarn count, loop length, and finishing % of the zone of inhibition (ZOI) against the Escherichia coli and Staphylococcus aureus microbes on cotton knitted fabric have been carried out. Result shows that except yarn count other parameters are not significant toward the ZOI against microbes.