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This paper seeks to build a mathematical model to deduct the twists distribution in the slub‐yarn.

The model, considering the shearing modulus and polar moment of inertia of the yarn, influenced by the yarn density, is established based on the bar torsion model. The twists distribution in the slub‐yarn is concluded based on the analysis of the results. The rules were verified via an indirect method, by testing the breaking strength of the slub‐yarn.

The results of the analysis showed that twists in every section of the slub‐yarn are in inverse proportion to the square of the line density of the corresponding section. Slub length is a key factor to the twist in the base yarn, and the increase of the slub length will increase the twist; while the multiple is the key factor to the slub twist, and the enhancement of the multiple will decrease the twist significantly.

The analysis cannot be verified via a direct method. A new, more conceivable direct method should be utilized to test the result.

The paper builds a base for the research of the mechanical properties of slub‐yarn and gives directions to the slub‐yarn production.

The traditional Japanese cotton-crepe fabric chijimi has been used for summer clothing for over a century because of its good skin comfort. The high extensibility of this fabric relies on the high-twist cotton yarns used in the weft direction. The purpose of this paper is to show the effect of environmental humidity on the extensibility of highly twisted cotton yarns to help in choosing weft yarn suitable for woven fabric.

Four highly twisted cotton yarns are examined under 10-90 percent RH and in 25°C water. Cyclic tensile tests are performed to obtain the tensile energy, resilience, extensibility at maximum applied load (EM), and residual strain.

Comparing the same yarn-count samples Y1 and Y2, the EM of Y2 (2,200 T/m) is larger than that of Y1 (1,000 T/m) under all RH conditions, and the difference increases at humidity over 60 percent RH. For fabric crepe samples woven by Y1 (warp) and Y2 (weft), the extensibility (EM-1) in the weft direction is in the range 16-26 percent, which is equivalent to that of outer-knitted fabrics. The extensibility and recovery of chijimi is largely dominated by the twist of weft yarns, which is also influenced by changes in relative humidity.

The skin comfort of Takashima chijimi has been of interest, but the high extensibility of this cotton fabric has not been given much attention. The results of this study show that yarn twist is key to controlling extensibility in high-humidity environments.

Sewing thread plays an important role in transforming a two-dimensional fabric into three-dimensional garment. Over the years, ring spinning has been dominating the yarn market because of its consistent performance. Eli-Twist spinning system, a new method of yarn manufacture, provides a product with improved mechanical and physical properties than the conventional ring-spun yarn. It is the process of producing a two-ply compact yarn with improved fibre utilisation. The purpose of this paper is to assess the feasibility of using Eli-Twist yarn as a sewing thread and to compare its performance with conventional thread.

In this study, regular polyester and Indian cotton were used to produce the Eli-Twist and conventional TFO thread. Three different blends (100 per cent polyester, 50/50 polyester/cotton [P/C] and 100 per cent cotton) were taken to produce three different counts (39.4 tex, 29.5 tex and 23.6 tex) from each composition. The hairiness, tenacity, breaking elongation and coefficient of yarn-to-metal friction of threads were tested and a comparative analysis was made. The seam performance of all the threads was judged by seam strength, seam efficiency and seam elongation.

The results show that the mass irregularity and imperfections are more or less similar for both types of threads. Eli-Twist sewing thread has shown less friction, less hairiness and higher tensile strength. The Eli-Twist sewing thread was found to be better than the conventional two-ply sewing thread. The seam performance parameters, such as seam strength, seam efficiency and seam elongation of the Eli-Twist thread showed significantly improved performance.

The main concern of this study is delineating the performance of the Eli-Twist sewing thread. No study in this regard has been reported so far. The improved physical and mechanical behaviour of the Eli-Twist yarn has prompted to assess its performance as sewing thread.

Dref-3 friction spun core yarns produced using staple fibre yarn as the core, e.g. Jute core yarn wrapped with cotton fibre, have poorer mechanical properties compared to the core yarn itself. The purpose of this study was to understand the structure of such yarns, that will lead to the optimization of fibre, machine and process variables for production of better quality yarn from the Dref-3/3000 machines.

The Dref spinning trials were conducted following a full factorial design with six variables, all with two operative levels. The Dref-3 friction spun yarn, in which the core is a plied, twisted ring yarn composed of cotton singles and the sheath, formed from the same cotton fibres making the singles, has been examined. The structures have also been studied by using the tracer fibre technique.

It was observed that rather than depending on the plied core yarn, the tensile properties of the Dref-3 yarn are significantly determined by the parameters those affect the constituent single yarn tensile properties, i.e. the amount of twist and its twist direction, yarn linear density and the sheath fibre proportion used during the Dref spinning in making the final yarn. Further, when the twist direction of single yarn, double yarn and the Dref spinning false twisting are in the same direction, the produced core-sheath yarn exhibits better tensile properties.

The understanding of the yarn structure will lead to optimized production of all staple fibre core Dref spun yarns.

The research work may lead to utilization of coarse and harsh untapped natural fibres to the production of value-added textile products.

Though an earlier research has reported the effects of sheath fibre fineness and length on the tensile and bending properties of Dref-3 friction yarn, the present study is the first documented attempt using the tracer fibre technique to understand Dref-3 yarn structure with plied staple fibrous core.

In the present work, the effect of water on some physical properties of false-twist textured polyamide 6 yarn was studied. A laboratory false-twist texturing machine was modified by a water bath in order to wet the feed yarn before entering the texturing zone. Polyamide 6 yarn was textured at the texturing speeds of 51, 85 and 119 m/min and twist levels of 2165, 2559 and 2954 turns per meter, with and without water bath. The properties of textured yarn in the aspects of crimp characteristic and tensile behavior were determined. The properties of wet textured yarn were also compared with normal (dry) textured yarn. The results show that the tensile and crimp property values of wet textured yarn are lower than those of normal (dry) textured yarn. Wetting of feed yarn changes the stability of twisting–untwisting process in false-twist texturing, and it seems that some fraction of twist is maintained in the final textured yarn. This residual twist results in non-bulky appearance of wet textured yarn.

Fabrics’ thermal properties greatly influence human comfort during wear. For this reason, fabrics with optimum thermal properties need to be developed. This paper aims to investigate the effect of weft yarn twist levels on thermal and surface properties of 100 per cent cotton woven fabrics.

Five types of plain woven cotton fabrics were manufactured using weft yarns with 900, 905, 910, 915 and 920 twists/meter (Tpm). The other parameters of the samples as count, thread density and fabric structures were kept constant. Fabric thermal properties were evaluated by measuring its thermal conductivity, thermal resistance, actual insulation, water permeability, air permeability and wicking ability. The fabric compression and surface properties were also evaluated because they contribute to the overall clothing comfort.

The results showed that actual insulation and thermal resistance property decreased with an increase in twists/meter of the weft yarn. However, thermal conductivity does not significantly change while fabric compression reduced with an increase in twist as the surface roughness increased.

Comfort is a fundamental requirement in human daily existence, and it is greatly influenced by clothing, which comes in close contact with the human skin. Fabrics’ thermal properties greatly influence human comfort during wear. For this reason, fabrics with optimum thermal properties need to be developed.

In order to develop high shape retention yarn and investigate the effects of spinning process and core yarn contents on the shape retention of yarn, in this paper, three kinds of yarns, JC/T400 18.5tex (55.6dtex) core-spun yarn, JC/T400 18.5tex (44.4dtex) core-spun yarn and JC18.5tex pure cotton yarn were spun by using the complete condensing Siro-spinning technology. The paper aims to discuss these issues.

In this paper, the core-spun yarns were spun by using the complete condensing spinning and Siro-spinning technology. Two key spinning processes, yarn twist factor and core yarn pre-draft ratio, were optimized by using the orthogonal test method first. Then, via the variable control method, the position of the core yarn, the position of the bell mouth and the center distance between two bell mouths were optimized, respectively, and corresponding optimal spinning process of the three yarns was determined. Finally, the yarns were spun under the optimal process, and the performance of the spun yarns was tested and compared.

Results show that the yarn twist factor affects yarn strength and hairiness, the position of bell mouth affects the evenness and hairiness of the yarn mainly, and the position of the core yarn affects the coverage and hairiness of the yarn. For the Z-twist spinning, the core yarn enters the front roller from the left side of two strands center, which is beneficial to improve the covering effect of core yarn, and reduce the pilling phenomenon of the yarn. The contents of core yarn affect indicators of the yarn shape retention, such as yarn strength, elastic recovery and abrasion resistance.

The shape retention of yarns affects the shape retention of fabrics, and the production of yarn with high shape retention is a key step in achieving shape retention of fabrics. At present, there are little studies on the shape retention of yarns, most researchers shave focused on shape retention of fabrics. Using the complete condensing Siro-spinning method to spin the core-spun yarn can improve the quality of the yarn. Compared with traditional ring-spinning yarns, the addition of the core yarn can improve the shape retention of the yarn.

No study was published about the tensile properties of different sections of multicount yarn. Hence there was a need to conduct a detailed section-wise tensile study of fancy multicounty yarn. The purpose of this study is to identify the different sections of the same multicount yarn and test them separately.

Multicount yarn with slubs were prepared on a ring frame with the Amsler Textile Effect System. Different yarn sections from each multicount yarn are identified as fine normal, fine slub, medium normal, medium slub, coarse normal, coarse slub and the changeover sections. These sections are tested for the breaking load and breaking elongation. Broken ends of the yarn sections are also studied, and these broken ends are classified as sharp broken end, tapered broken end and slipped broken end. A study is also conducted on the location of break or the place of break at the changeover sections.

It was found that the twist of yarn at slub sections was lower than the twist at normal sections. In spite of the low yarn twist at slub sections, the breaking load of the yarn was higher at slub sections than at normal sections by 12 to 30 per cent owing to the presence of more number of fibres that share the breaking load. The breaking load at the changeover section (normal to slub and slub to normal) was found to be higher than that at normal section and lower than at slub sections. No significant difference was found between the breaking load of the two changeover sections (normal to slub and slub to normal). The majority of breaks in normal yarn sections were of the tapered broken end type and the majority of breaks in slub yarn sections were slipped broken ends.

Efforts are taken to identify different sections of the same multicount yarn with the help of specially designed square black board and tensile study of these sections are carried out.

Presents the mechanical models of ring, rotor and air‐jet staple yarn formation. The analysis of formation peculiarities has enabled the establishment of differences among them in micro‐ and macrostructure as well as in their mechanical and physical properties. The comparison of yarn and fabric quality parameters will be very valuable for weavers, knitters, garment manufacturers, finishers and designers. Gives productivity, spinability and economic factors for ring spinning, OE‐rotor and air‐jet spinning processes.

The tourist sector in Mauritius is aiming at welcoming 2 million tourists by the year 2015 and coming up with creative ideas and products branded with ‘Made in Mauritius’ to boost the country’s craft sector. This project looks into the manufacture of paper-yarn. Different types of paper were cut into ribbons of varying widths and converted into yarn by two methods: twisting and folding. The folds were made along the axis of a ribbon while twisting required prior moistening and was carried out on a modified yarn-twist measuring device. The relationship between the number of folds/twists and the strength of the resulting paper yarn was investigated. Yarn of high quality can be obtained by twisting ribbons of relatively smaller widths or folding relatively wider ribbons. The yarn can be used for manufacturing craft products.