Filament Yam Research Articles

The Effect of Twist Angle on the Modulus in Worsted and Semi-Worsted Staple Yarns

This paper is concerned with the prediction of the tensile properties of worsted (spun wholly from combed wool in which the fibres are reasonably parallel) and semi-worsted (in which combing operation is skipped) yarns spun from 100% Wool, Polyester, Nylon, Viscose and Acrylic fibres. In the review of the literature, the work done by various researchers on continuous filament yams is highlighted. In the experimental work, it was found that the reported equations for modelling the behaviours of continuous filament yams were useful for predicting the behaviour of staple yarns, i.e., those spun from fibres of limited lengths. Although the published theoretical work did not fit the practical case exactly, the equations relating yam and fibre moduli gave acceptable values for staple yarns once an appropriate correction factor was introduced. Journal of Agriculture, Science and Technology Vol. 2 (1) 1999: 71-76

Combination Effects of Open-End Rotor Spun Hybrid Yarns

We have developed a mechanical hybrid yarn spinning system that produces different yam types on a modified open-end rotor spinning frame. In order to improve yam properties and produce novel yams, we investigate the effects of combinations with typical hybrid yams by inserting two filament yarns with varying filament over-feeds. The results are a new rotor spun loop (RSL) yam made by combining two aspects of typical hybrid yarn production into one process, and an RSL yam where a filament yam, fed with a core filament over-feed (CFOF), is located in the center of one yarn and the other filament yam, fed with the effect filament over-feed (EFOF), makes a loop on the yarn surface. The stable conditions of RSL yam production are within a range of EFOF ≧ 4 (m/min) and -6.0 << CFOF << -4.0 (m/min).

Luster Properties of Polyester Filament Yarn Woven Fabrics

Polyester filament yam fabric specimens, plain, twill, and satin with varying levels of yam twist, are prepared to measure their luster properties. Images of the fabrics under specific illumination and viewing angles are acquired for further luster characterization, since the reflectance properties of the fabrics are highly angle-dependent. Along with the image analyses, goniometric luster is analyzed at varying angles to support macrolevel luster characterization. As yam twist increases, the luster unit size diminishes accordingly, resulting in macrolevel gloss decreases. While conventional goniometric gloss measure ments represent the macrolevel luster properties of fabrics, detailed analyses of luster images provide an explanation of the "quality" of fabric luster.

Twisting Mechanisms of Open-End Rotor Spun Hybrid Yarns

We have developed a mechanical hybrid yam spinning system that produces different kinds of yam on a modified open-end rotor spinning frame. In order to understand the characteristics of hybrid yam and produce novel yarns, it is necessary to investigate yarn formation and the twisting mechanism in the spinning rotor during yam production. Our results reveal that the rotor revolution generally results in combining the filament yam and the staple fiber strand. The fiber twist angle of the strand in a hybrid yarn is smaller than that of a rotor spun single yam with the same spinning conditions. Although a fed filament yam has a false twist inserted by increasing the filament over-feed, the filament yarn in the hybrid yarn has a smaller level of fiber twist angle in the same direction as the twist of the staple fiber strand due to untwisting of the false twist.

Evaluating Yarn Crimp with Fractal Geometry

Fractal geometry is used to evaluate the irregularities of crimped filament yarns. To measure the fractal dimension of textured filament yarns, methods based on the box counting dimension, the compass dimension, and the equipaced dimension are applied to digital images of the textured filament yarns, obtained using a charge coupled device (CCD) camera. For textured PET filament yams, as the crimp and twist level increase, higher values of fractal dimension are obtained, confirming that the fractal dimension can be used to evaluate fiber crimp. The fractal dimension and crimp also show an exponential relationship, which is well verified experimentally. Therefore, time-consuming direct measurements of fiber crimp may be effectively replaced by this automatic process, based on the acquisition of crimp images and fractal dimension analysis. The ideal sine wave. which has an equal length, crimp, and twist per meter, is synthesized as a topological model to study the physical properties of crimped yarn. This sine wave study shows that the major parameter of the crimped structure is the period of the crimp, and the dominant effect of yarn shrinkage development in boiling water is the increment of crimp amplitude.

Air Interlaced Yarn Structure and Properties

The air interlacing technique is used to introduce intermittent nips to a flat filament yam so as to improve its performance in further textile processing. Observation of the interlaced flat yam nips reveals that their structure is very complicated and can be categorized into four classes: twist, braid, wrap, and entanglement nips. The formation of these nip structure classes is largely affected by the condition of filament separation prior to mingling. Interlacing causes deterioration to filament yam mechanical prop erties to various degrees, depending mainly on processing conditions, and the change in yam properties is correlated to nip structure characteristics.

Dynamic Mechanical Properties, Superstructure, and Texturability of PA 6.6 Partially Oriented Yarns

The results of dynamic mechanical testing of five industrially produced partially oriented yams (POY) and two conventionally spun and drawn PA 6.6 filament yams are presented, along with some of their structural parameters. Dynamic mechanical spectra of POY samples differ from conventionally spun and drawn yams across the entire testing temperature range from 20 to 260°C according to their superstructure parameters. Differences in the low temperature range are primarily due to amorphous orientation, whereas differences in the high temperature range are ascribed to the perfection and stability of the crystalline structure. Preoriented yams of lower orien tation and unstable crystalline structure are more suitable for the simultaneous false- twist draw texturing process than the POY with more stable crystalline structures and higher orientation.

Influence of Interfilament Friction on Structure and Properties of Air Textured Yarns

The structure and properties of air textured yarns are influenced by the dynamic friction of the parent filament yam. We have demonstrated this by texturing under various conditions two similar multifilament yarns with different spin finishes. We have analyzed the effects of water and mechanical stretch on the structure and properties of the air textured yams. We present here a new classification of surface loops of air textured yarns and analyze the effect of interfilament friction and water on different types of loops.

Extension Due to Chain Slippage in Textile Fibers

This article tries to explain the differences in dynamic and static moduli. A math ematical expression is derived to estimate the amount of extension taking place in a fiber due to slippage of molecular segments when subjected to stress. Experimental results on viscose, polyester, and nylon filament yams verify the predictions of the proposed theory.

Effect of Drawing of Poly(ethylene Terephthalate) Fiber on Molecular Orientation

Polyester continuous filament yams were drawn at 36 and 200°C at four different draw ratios: 2.65, 3.0, 4.0, and 5.0. Crystallinity and molecular orientation were investigated using infrared spectroscopy, x-ray diffraction, birefringence, and sonic velocity. The densities were determined using the flotation technique, and sonic velocity was measured using a dynamic modulus tester PPM-5R. X-ray and infrared crystallinity indices of fibers changed because of the drawing, which could be further correlated with the data obtained by density measurement. Dyeing behavior was also investigated in terms of crystallinity changes caused by the thermomechanical process, and the changes in the molecular orientation because of drawing.

An Analysis of Roll Wrap Formation

Roll wraps occur frequently in spinning and processing continuous filament yams, and particularly in drawtwisting fully oriented yams. An analysis of roll wrap formation that agrees with experimental evidence shows that the following conditions must be met for a wrap to form: there must be a broken filament in the yam, the upstream section of the broken filament must separate from the main yam strand, the broken separated filament must directly contact the roll surface, and the forces acting on the broken filament at the roll surface must be distributed so that the filament is attracted to the roll and must be of sufficient magnitude and duration to induce one complete wrap. The forces acting on individual filaments in a multifilament threadline were analyzed, and the resultant force required for wrap formation was determined. Results from this analysis offer a reasonable explanation for the well-known roll wrapping behavior.

“合繊フィラメントカウンター”の開発

Although an irregular number of filaments are seldom occured in synthetic multi - filament yarns, a great of loss may be caused, if yarns of irregular number of filaments are used in the woven or knitted fabrics. It is, therefore, very important to detect and eliminate yarns of irregular number of filaments.The traditional method of examining these defective filament yams is to spread the filaments manually and to count visually the number of filaments one by one. This method is very complicated and is extremely low in working efficiency. This new filament counter has been developed to save the man power needed for this manual examination. In this method, the filaments are arrayed to a single layer without gap by using an arraying stand and a saddle style yarn guide. In the next stage, the number of the filaments are automatically counted with a photo-electronic device.This new filament counting method has been developed by combing an excellent human ability of pattern recognition and the simple repeating action of a machine. It has improved the working efficiency by 25 times comparing with that of the traditional counting method.