35—THE PREDICTION OF STRENGTHS OF LOCKSTITCH SEAMS IN WOVEN FABRICS

An absolute method of seam-strength testing is described. The effects of fabric type and gauge length on seam strength are examined. The effects of the type of sewing thread used and various measures of thread strength on the accuracy of seam-strength prediction are also investigated.

A simple method of determining the minimum loop strength of a thread is described. The efficiency of this value, corrected for one aspect of fabric construction, for seam-strength prediction is discussed.     

Analyzing the effect of the elastane-containing dual-core weft yarn density on the denim fabric performance properties

Denim fabrics form today’s mostly utilized fabric type. As is the case with the other textile products, there are many factors affecting the properties and the performance of the denim products. Within the scope of this study, we have evaluated the effect of the density changes in the use of the dual-core threads – used in an ever-increasing fashion in the textile industry – in weft have on the fabric properties. We have analyzed the extent to which the weight, size, elasticity, tensile strength, and cost properties of the denim fabrics woven with the dual-core weft thread in various densities are affected by the changes in the number of dual-core weft threads per unit length. In conclusion, we have come to such striking remarks as that the construction has a much more impact on the fabric width and thus on the unit weight than the elasticity ratio, and that density changes in the elastane-containing threads cause serious differences on the fabric’s color values.     

汉麻纱线拉伸性能及条干均匀度测试分析

使用单纱强力机和纱线条干均匀度仪测试了12种纱线的拉伸性能和条干均匀度,研究了夹持器隔距、拉伸速度、纱线干湿情况以及预加张力等参数对测试指标的影响程度,对比分析了汉麻纱和其它纱线的性能差异.结果表明,与其他纤维的纱线相比较,汉麻纱线强度和强度不匀都较大,伸长率很小,伸长率不匀偏大;汉麻纱吸湿后,强度有所增加,强度不匀率变化很小;隔距、拉伸速度对强度指标有一定影响,预加张力对测试结果影响很小.汉麻纱线的粗节、细节、棉节和CV值均明显高于其他纱线.     

涤纶仿毛长丝弯曲性能测试因素分析

为模拟涤纶仿毛长丝在实际织造条件下抗弯曲性能,对4种规格涤纶仿毛长丝的打结位置、拉伸速度和夹持距离等打结参数对其打结断裂强力和打结断裂伸长率影响进行探究。实验结果表明:长丝打结后的断裂强力和断裂伸长率比未打结状态下小,说明长丝弯曲后力学性能变差;打结位置偏离中心位置越远,打结断裂强力越小,而打结位置越接近拉伸下夹头位置,打结断裂伸长率越大;长丝打结后断裂强力和断裂伸长率遵循"弱环定律";打结断裂强力随长丝细度的增大而增大,但打结断裂伸长率与细度无关。     

集聚纱与非集聚纱的轴向应变及其对纱线拉伸性能的影响

通过试验重点研究了轴向应变对集聚纱拉伸性能的影响。拉伸性能主要涉及断裂强度、断裂伸长和断裂功。选择不同的应变速率和纱线夹持长度,对9.7 tex集聚纱和非集聚纱进行拉伸测试,然后根据Meredith试验过程绘制不同应变速率和夹持长度条件下各自的负荷-伸长曲线,同时测量各曲线三个区域的斜率。测试结果表明：两种9.7 tex的纱线（集聚纱和非集聚纱）随着应变速率的增加,断裂强度均增加,但当断裂伸长增加到一定程度,且在较高应变速率下,断裂强度有所下降;两种纱线随着夹持长度的增加,断裂强度和断裂伸长均降低;两种纱线的斜率随着应变速率的增加均增加,但随着夹持长度的增加而下降。试验还发现,非集聚纱的斜率变化较大,而集聚纱的斜率变化较小。     

编织结构玻璃长丝缝合线的打结强度

针对玻璃纤维丝束在纺织预制件或预浸料的缝合过程中易发生断裂的情况,设计了二维管状编织结构的玻璃纤维缝合线。采用Instron电子万能试验机对不同编织工艺参数的缝合线试样分别进行了loop结和knot结的拉伸强度测试,分析了拉伸断裂的机制和破坏模式。结果表明：编织结构玻璃长丝缝合线的打结强度和断裂伸长率明显高于玻璃丝束;花节长度是影响打结性能的主要因素;试样在试验过程中受剪切和拉力共同作用,经历伸直-受力-断裂几个阶段,试样断口基本平齐。     

Measuring the strength of knotted suture materials

There is no international standard method for measuring the strength of knotted suture materials, and although several methods have been published, there has been minimal investigation on the effects of test variables on measured properties (e.g. speed, gauge length, and knot tensioning force). Methods investigated in this work were the “ear method” (with and without a rod inside the loop), and the “cut-loop and ear method”. The test environment, material, and type of knot were constant. Effects of varying gauge length, test speed, and knot-tensioning force on tenacity and strain were investigated and compared with data for nonknotted sutures. Different values of tenacity and strain were evident for the different test methods; lower values of tenacity for specimens with shorter gauge lengths and tested at greater speeds; lower values of strain for specimens with longer gauge lengths and tested at greater speeds. Thus, tensile properties of suture materials tested at one gauge length or one test speed, as widely reported in the literature, may be misleading. Knot tensioning force neither affect tenacity nor strain.     

勾结参数对涤纶长丝强力的影响

使用双立柱电子万能材料试验机,选择4个不同的勾结位置、4种不同的拉伸速度,设定3种夹持距离,对4种涤纶FDY长丝的勾结断裂强力和伸长率进行测试。结果表明:长丝未勾结的强力和断裂伸长率之比比勾结状态下的大,勾结位置越偏离中心位置,强力越大,而勾结位置对勾结断裂伸长率影响不明显;夹持距离在100 mm到500 mm,长丝勾结后强力和断裂伸长率遵循"弱环定律";随着长丝纤度的增加,强力呈逐渐递增趋势,而断裂伸长率随纤度变化不明显。     

Influence of some sewing parameters upon the sewing efficiency of denim fabrics

This paper reports an experimental investigation of the effect of the seam threads linear density, the stitch density and some fabric properties on the seam efficiency. Furthermore, on the basis of the seam quality parameters, regression models were determined in order to predict seam efficiency. In this work, 18 denim fabrics, having different compositions and masses, were sewn with two commercial sewing threads. Their performances, ranked according to the seam quality, were also determined. The seam efficiency was calculated by determining of the seam tensile strength and the fabric tensile strength. It was concluded that the increase in the seam thread linear density increases the seam efficiency, as well as the stitch density. However, the fabric mass has a random effect on seam efficiency. About the composition, we conclude that the seam efficiency decreases with polyester but increases with elastane. According to the seam direction, it was found that, in the weft direction, the seam efficiency was more important than in the warp direction.     

Analyzing the effects of special washing processes on characteristics of sewing threads

In recent years, wet (washing, bleaching, etc.) and dry (abrasive, laser shaping, rodeo, etc.) operations applied on fashion denim products have become an important factor to increase the added value. However, these wet and dry processes applied to the denim products may have adverse effects on the strength of the fabric and other supplementary materials of denim products. For example, thread breakages affect the repair ratios and quality of products, which causes time and profitability losses in companies. The main objective of this study is to analyse how the types of washing affect the strength of the sewing threads that are commonly used in the production of denim trousers. In this study, 100% cotton denim fabric with a weight of 11.5 ounces and two different sewing threads were used. The fabrics are sewn as trouser legs with chain and lock stitch. Five different washes were applied to the trouser legs. The obtained data were evaluated in the R statistical program. As a result of the analyses made it is proven that the washing techniques used have an effect on the sewing threads’ tensile strength and elongation at break. The tensile strengths of lock stitch and chain stitch decrease averagely 35% and elongation at break of lock stitch decreases %22 and chain stitch decreases 29.8%.     

回潮率对石英纤维纱织造前后力学性能的影响

为研究导致石英纤维纱使用过程中强度下降的主要因素,对石英纤维纵、横截面及形貌进行表征,测试不同回潮率、不同线密度石英纤维纱织造前后拉伸断裂强度,分析织造过程中整经、开口、打纬等对其力学性能的影响,并探究浸润剂对石英纤维纱力学性能的影响。结果表明:石英纤维纱的拉伸断裂强度随回潮率增加而显著下降,其中95 tex石英纤维纱当回潮率为100%时比0%时拉伸强度降幅最大可达41%;95 tex石英纤维纱在1.0%回潮率织造后,其纤维拉伸强度下降高达60.94%;添加浸润剂对纤维纱强度有明显增强效果,390 tex石英纤维纱添加体积分数为100%浸润剂时,纱线强度增加17%;二氧化硅吸湿及浸润剂吸湿是导致石英纤维纱强度下降的主要原因。     

Morphology of the Bagasse Fibers Obtained from the Elaboration Process of Mezcal and Effects on Their Tensile Properties

The morphology of the cross-section and longitudinal-section of bagasse fibers of Agave angustifolia Haw from the elaboration process of mezcal were investigated and tensile tests were performed in function of the diameter (0.20–0.79 mm), gauge length (10, 15 and 20 mm) and strain rate (5–50 mm/min). The cross-section of the fibers is ribbon-shape like with dislocations and the longitudinal section has mechanical damage in its surface. The ultimate tensile strength (14.83–86.51 MPa) and Young’s modulus (0.20–1.26 GPa) are influenced by the diameter and the strain rate, while the strain at failure (16–26%) is influenced by the gauge length. These results are discussed in light of information on relationship between morphology and tensile properties of natural fibers and possible effects of the elaboration process of mezcal.     

生丝束纤维拉伸参数与隔距的关系

文章运用澳大利亚CSIRO的束纤维强力仪（SIROLAN-TENSOR）对蚕丝纤维进行了束纤维强伸性快速测试,并对拉伸曲线的合成、典型拉伸曲线进行了分析,研究了隔距长度对束纤维强力相关参数的影响,提出了新的参量如断裂区域衰减模量（AM）。     

PUS—01阴离子淀粉在马尾松枝桠材浆造纸中的应用研究

本文探讨了PUS－01阴离子淀粉在枝桠材松木浆中的增强作用,确定了最佳使用量。实验结果表明,当添加2％的阴离子淀粉,可使纸张裂断长增加22．13％,抗张强度增加13．22％;当添加1％,伸长率增加43．49％,而对抗张能量吸收值（TEA）增长幅度也较大。     

从金丝的起源到纺织用金线的专门化

为探索古代金线在中国的起源方式及起源时间,通过对最早出现于秦及西汉时期的甲胄、玉衣等用于穿戴的非传统“纺织品”上金属单丝应用的分析与考证,认为纺织用金线起源的原始形式就是金属单丝,即打制、拉拔而成的金丝,并在秦至东汉末年的300-400年间逐步转变,继而以拉拔金丝、切片金线的形式钩挂或交织于早期的古代织物中。结合古代金线及织物的相关文献资料,通过对历史各时期出土的金线实物进行总结,基于制作工艺方法的不同,将古代金线分为片金线和捻金线两大类,并发现在唐宋时期纺织用金线已经具备专门化特征,且在元代及后世得到迅速且更大规模的发展。     

Manufacturing nanofibrous bundles and the roller drafting effects on the bundle properties

This research reports a new product form made of nanofibers and the method used to produce it. Nanofibers are electrospun into a web form on a moving collector and the web is continuously transformed into a bundle by passage through a condenser. Since the web is made of loops of nanofibers and peeled off from the collector surface, the condensed bundle deforms very easily and is too weak for further processing. Thus, the bundle is drafted through a roller drafting system to improve the fiber array in the bundle length direction in various levels of draft temperature, since the temperature may affect the bundle drafting process and thus the bundle properties. Using a newly designed system, we tried to produce nanofibrous bundle of polyvinylidiene difluoride. The nanofiber arrangement and the tensile properties of the bundle were measured before and after the roller drafting process under various conditions. Results showed that the technology suggested in this paper had the feasibility to manufacture a new product form composed of nanofibers, which implied the possible improvement of the productivity and product quality. Thickness reduction of the bundle occurring during the roller drafting straightened the nanofiber loops in the bundle and rearranged the nanofibers along the bundle axis. The drafting process was affected by the process temperature. Uni-axial tensile tests demonstrated that the bundle strength reached 4.8 cN/tex, and the strain at breakage was 0.087, when the draft ratio was 4.0 and the temperature 110 °C, whereas the raw nanofiber bundle in process had a strength of 0.014 cN/tex and the strain at breakage of 0.65. The thickness of the constituent nanofibers was not significantly affected by drafting.     

采用正交实验进行服装缝纫工艺的参数设计

缝口强度是服装企业成衣加工质量控制的要素,研究仅选择成衣生产中缝迹、缝线强度、线迹密度和针尖形状等缝纫参数进行正交实验,求得优化的缝纫工艺参数组合.研究表明,对于弹力面料来说,优化的缝纫参数组合为:双线链式缝迹,缝纫线为30.9 tex的涤纶线,线迹密度为14针/3cm,针尖形状为U形;缝迹对缝口强度的影响最大,缝线强度和线迹密度对缝口强度的影响力相当;针尖形状对缝口强度的影响最小.     

经编间隔织物的拉伸特征

为探讨经编间隔织物的拉伸特征,选取4种不同结构的织物进行拉伸试验,分析了各织物及其上下表面层的断裂强力、断裂伸长和拉伸曲线特征,解释了经编间隔织物的拉伸机制和三维尺寸变化规律,并从织物层角度讨论对拉伸强力和断裂伸长的影响。实验结果表明:间隔织物三维尺寸的变化在拉伸过程中呈现出不同的规律;断裂伸长较小的间隔织物表面在拉伸过程中会率先发生断裂;间隔层对间隔织物的拉伸强力和断裂伸长影响较小,但会延长间隔织物拉伸断裂过程;上下表面层的强力和伸长数值及其大小关系共同决定着间隔织物的断裂强力和断裂伸长。     

Prediction of spun yarn strength at different gage lengths

In this article, the influence of tensile tester gage length on ring, rotor and air-jet spun yarns tenacity and its coefficient of variation have been investigated. A statistical model has been presented that correlates yarn tenacity and coefficient of variation of yarn tenacity to gage length. The model is based on Peirce model and assuming the three-parameter Weibull distribution of yarn strength values. A reasonable agreement has been shown between the experimental and predicted values. The model successfully captured the change in yarn strength and its coefficient of variation at different gage lengths. Results showed that at longer gage lengths, yarn strength decreases and its coefficient of variation decreases as well.     

马尾松回用纤维品质衰变规律及其机理研究

通过对马尾松亚硫酸盐浆、TMP浆和GWP浆的回用实验,本文得出了回用纤维品质衰变的基本规律。根据著名的Page方程,从回用纤维中聚戊糖含量的变化和回用纤维长度分布的变化以及回用纤维纸页光散射系数变化等数据中推断出了影响回用纤维品质衰变的主要因素,并进一步探讨了这些因素影响回用纤维品质的机理。