The effect of spinning parameters on mechanical and physical properties of core-spun yarns produced by the three-strand modified method (TSMM)

The effect of spinning parameters on core-spun yarns properties manufactured using three-strand modified method (TSMM) was analyzed. Of the various spinning parameters, strand spacing, yarn linear density and yarn twist have a crucial effect on core-spun yarn properties. To achieve the objectives of this research, general physical properties of core-spun yarns together with existing standards were thoroughly studied. First of all, the strand spacing and yarn linear density were optimized. Afterwards, the effects of variation of yarn twist and sheath roving linear density on core-spun yarns properties were investigated. Finally, the physical and mechanical properties of TSMM yarns were compared with those of siro and conventional ring core-spun yarns counterparts. It was found that, the best strand spacing and yarn linear density to produce core-spun yarns are 8 mm and 45 tex, respectively. Results showed that, tenacity of TSMM yarns increases up to a certain twist level beyond which it reduces. The result confirmed that 45 tex yarns produced by three rovings of the same count are superior with regards to tenacity and hairiness. The optimized yarns produced by three-strand modified method enjoy superior physical and mechanical properties in comparison to the ring and siro core-spun yarns.     

Performance of cotton single yarns and knitted fabrics produced by a 2-step spinning method

A low torque spinning method has been recently developed by integrating the ring spinning process with false twisting techniques. As a result of false twist and true twist, a novel single yarn of low torque and soft handle is generated. Based on the similar spinning principle, this paper proposed a 2-step spinning method, which is composed of twisting-anduntwisting operation and can be considered as a variant of the low torque spinning method. The proposed spinning method separates the false twisting process into twisting and untwisting processes which are combined in one step in the low torque spinning method. In this paper, physical properties of yarns produced by the proposed spinning method were evaluated and compared with the conventional yarns. Influences of various spinning parameters on the properties of 2-step yarns were also examined. Furthermore, a systematic study of the physical properties of the 2-step yarns and resultant fabrics with respect to the conventional and low torque ones was carried out. The experimental results showed that the 2-step yarns exhibit slightly higher tenacity, lower wet snarl and much less hairiness than the conventional yarns, which, however, are inferior to the low torque yarns, particularly the evenness. The fabrics made by the 2-step yarns show the softest handle feeling, best airpermeability and moderate spirality angle with acceptable pilling resistance.     

Properties of wool/spandex core-spun yarn produced on modified woolen spinning frame

Spandex has been successfully applied on modified worsted spinning system to produce spandex core spun yarn. However it’s difficult to produce wool/spandex core-spun yarn on woolen spinning system with the same modified device because the drafting device of the two systems is quite different. A new method is introduced to apply spandex on woolen spinning system in this paper. Core-spun yarn produced in this way has good appearance and quality by comparing with normal yarn. A series of experiments were carried out to study the influence of spandex drafting ratio and yarn twist factor on tensile properties and elasticity of core-spun yarns. The results indicate that core-spun yarn with spandex drawing ratio of 2.5 and twist factor of 13.63 has highest value of tenacity and breaking elongation.     

Study on Spinning triangles in the common ring spinning and Super draft ring spinning systems

In the paper, one kind of super draft ring spinning frame with four drafting rollers and corresponding three drafting zones were introduced. The yarn qualities spun by the super draft ring spinning frame were analyzed by studying the shape of spinning triangles. Using the high speed camera system OLYMPUS i-speed3 and one kind of transparent front top roller, the spinning triangles were captured, and the geometry size of spinning triangle were measured. Then, according to the theoretical model of fiber tension in the spinning triangle, fiber tension distributions in the spinning triangles were presented by using Matlab software. Using the combed roving of 350 tex as raw material, three kinds of cotton yarns, 27.8 tex (21^S), 18.2 tex (32^S) and 14.6 tex (40^S), were spun in the common ring spinning frame with three different suitable spindle speeds, travelers and twist factors. Using the combed roving of 350 tex and 500 tex as raw material, 14.6 tex cotton yarns were spun in the super draft ring spinning frame with three different drafting ratios at back zone. It is shown that with the increasing of spindle speed, a more asymmetric shape of spinning triangle would be produced, and lead to worsen yarn evenness. With the decreasing of traveler weight, the height and horizontal deviation of the spinning triangle is decreased, and may lead to better yarn evenness and less long hairiness. By taking suitable large yarn twist factors, the comprehensive qualities can be improved. Comparing with the common ring spinning, the spinning triangle is larger in the super draft ring spinning. That is, in the super draft ring spinning, the fibers in the strand in the front roller nip are more dispersed, and not benefit for yarn qualities. Therefore, the compact device was introduced into the super draft ring spinning, and the cotton pure yarns and blend yarns were spun, and the yarn qualities were measured and analyzed.     

An experimental study of influence of filament and roving location on yarn properties during embeddable and locatable spinning

This study was focus on the influence of filament and roving location on yarn properties during embeddable and locatable spinning (ELS). ELS composite yarns were produced with various filament and roving locations on an experimental ring spinning frame. Besides yarn formation zone configurations, ELS yarn properties were compared including yarn hairiness, unevenness and tensile properties. Results showed that spinning triangles became larger; however, the reinforced composite spinning strand length kept constant. With a constant filament-roving spacing on each side of ELS, Filament spacing variations caused no significant changes of spun yarn hairiness, tenacities, imperfections and unevenness CV. For roving location variations with constant filament spacing, the reinforced strand length became longer as the roving spacing increased. Hairs exceeding 3 mm were lower for ELS yarn spun with 4 mm and 10 mm roving spacings than that spun with 6 mm, 8 mm and 12 mm roving spacings. Roving spacing variations had a trivial influence on ELS yarn unevenness; whereas, yarn tensile index variation coefficients fluctuated dramatically due to hairiness variations for different roving spacings.     

Structural analysis of finer cotton yarns produced by conventional and modified ring spinning system

Yarn structure plays an important role in determining the properties of spun yarns. Recently, a modified spinning technique has been developed for producing a low torque and soft handle singles yarn by modifying the fiber arrangement in a yarn. Comparative studies revealed that the finer modified yarns possess significantly higher strength and lower hairiness over the conventional yarns of the same twist level, implying a different structure of finer modified yarn. Thus this paper aims to quantitatively study the structures of the finer conventional and modified cotton yarn (80 Ne) produced at the same twist level. Various measuring techniques, namely the Scanning Electron Microscope (SEM), cross section technique and tracer fiber technique, are adopted to analyze their structural characteristics, including fiber configuration, fiber spatial orientation angle, fiber packing density, yarn surface appearance, and fiber migration behavior. Results showed that finer modified yarns exhibit a smoother surface and much more compact structure with less hairiness. The fibers in the finer modified yarn have a complicated fiber path with relatively lower fiber radial position, larger migration frequency and magnitudes. In addition, it was noted that 73% of fibers in the finer conventional yarn follow concentric conical helix, which is contrary to those in the coarser conventional yarn. The analyses conducted in this paper provide deep insights into the mechanism of modified spinning technique and evidential explanations on the difference of properties between the finer conventional and modified yarns.     

An experimental investigation of yarn tension in simulated ring spinning

Yarn tension is a key factor that affects the efficiency of a ring spinning system. In this paper, a specially constructed rig, which can rotate a yarn at a high speed without inserting any real twist into the yarn, was used to simulate a ring spinning process. Yarn tension was measured at the guide-eye during the simulated spinning of different yarns at various balloon heights and with varying yarn length in the balloon. The effect of balloon shape, yarn hairiness and thickness, and yarn rotating speed, on the measured yarn tension, was examined. The results indicate that the collapse of balloon shape from single loop to double loop, or from double loop to triple etc, lead to sudden reduction in yarn tension. Under otherwise identical conditions, a longer length of yarn in the balloon gives a lower yarn tension at the guide-eye. In addition, thicker yarns and/or more hairy yarns generate a higher tension in the yarn, due to the increased air drag acting on the thicker or more hairy yarns.     

Comparative study on the characteristics of knitted fabrics made of vortex-spun viscose yarns

Murata vortex spinning system is based on the air jet spinning system. The vast majority of previous works deal with the properties of vortex spun (VS) yarn and the spinning system. In this study, we investigated knitted fabrics from VS yarn in comparison with fabrics from ring (RS), compact (CS) and open-end rotor (OES) spun yarns made from viscose. The effect of yarn spinning system on dimensional and physical properties of knitted fabrics was explained with specific attention to fabrics from VS yarn. Shrinkage of fabrics from VS yarn has the lowest at widthwise direction, while having the highest at lengthwise direction. It is shown that the order of fabric spirality and twist liveliness for yarns from different spinning systems are quite similar. However, relation between loop shape factor and angle of spirality is inconsistent. Angle of spirality of fabrics from VS yarn is higher than fabrics from OES yarn, but lower than that of others. The bursting strength of fabrics from VS yarn is lower than that of those from RS and CS yarns and higher than that of those from OES yarn. From this study, it is also evident that fabrics from VS yarn have the lowest pilling tendency and highest resistance to abrasion.     

Investigation of Parameters for Preparing Nanofiber Yarn via a Stepped Airflow-assisted Electrospinning

Electrospinning is a simple and cost-effective method to prepare fiber with nanometer scale. More importantly, 3D flexible nanofiber yarns that fabricated by electrospinning have shown excellent application prospects in smart textiles, wearable sensors, energy storage devices, tissue engineering, and so on. However, current methods for preparing electrospinning nanofiber yarns had some limitations, including low yarn yield and poor yarn structure. In this paper, a stepped airflow-assisted electrospinning method was designed to prepare continuously twisted nanofiber yarn through introducing stepped airflow into traditional electrospinning system. The stepped airflow could not only help to improve nanofiber yield, but also good for controlling the formed nanofibers to be deposited in a small area. In addition, the experimental methods of single factor variables were used to study the effects of stepped airflow pressure, applied voltage, spinning distance, solution flow rate, air pumping volume and friction roller speed on nanofiber yarn yield, nanofiber diameter, yarn twist and mechanical property. The results showed that prepared nanofiber yarns exhibited perfect morphologies and the yield of nanofiber yarn could reach to a maximum of 4.207 g/h. The breaking strength and elongation at break of the prepared yarn could reach to 23.52 MPa and 30.61 %, respectively.     

Influence of the core-sheath weight ratio and twist on the tensile strength of the ring core yarns with high tenacity filaments

Core spun yarns are applied for various purposes that especially require the multi-functional performance. This research reports on the core spinning effect on the yarn strength. We prepared various core yarns by combining different kinds of high tenacity filaments in core with cotton staples in sheath with various twist levels in the ring spin system. And the tensile strength was tested to investigate the contribution of the core-sheath structure to the core yarn strength. The influence of the twist level was also checked up on the relationship between the core-sheath structure and the yarn strength. Results turned out that the core-sheath weight ratio had influence on the tensile properties of the ring core-spun yarns in different ways according to the core filaments used for the yarn. Increasing the twists yielded a monotone decreasing strength for the aramid and the basalt core yarns, while the PET core yarns showed almost unchanged strength, which could be ascribed to the extensional property of the filaments.     

Yarn setting and hairiness reduction with a steam jet during winding

This paper examines the use of pressurized steam for wrapping and setting the yarn hairs concurrently via a new steam-jet process during winding. Yarn torque can also be stabilized as an added advantage. The results obtained with two batches of pure wool yarns suggest that there is potential to achieve yarn hairiness reduction of up to 60 % with minimum deterioration in hairiness even after subsequent rewinding.     

Analysis of resistance torque on the compact spinning with suction groove

The compact spinning with suction groove can eliminate or decrease the spinning triangle by airflow compacting and shape condensing of the groove, so the yarn hairiness can be reduced effectively for long staple fiber. But the resistance torques produced by the spinning tension and the negative pressure of airflow influence the twist propagation. This paper analyzes variation of the friction coefficient between the fiber bundles and the groove. The transfer process of the moment of the spinning tension and airflow is studied in the variation of the friction coefficient. The expression of the resistance torque is established in the gathering area. The results show that the many factors influence the resistance torque, such as the horizontal friction coeffecient between the fiber bundles and the groove, the spinning tension and the negative pressure, as well as the angle between two suction holes etc. The proper negative pressure and the spinning tension can prevent twist propagation, and can reduce the yarn hairiness and improve the yarn quality.     

Effects of bleaching and dyeing on the quality of alpaca tops and yarns

This paper reports the effects of bleaching of alpaca tops and dyeing of bleached alpaca tops/yarns on the quality of tops and yarns. A dark brown alpaca top was bleached with hydrogen peroxide. Two bleaching methods were tried for effectiveness of color removal. A portion of each bleached top was dyed after bleaching. Color parameters were examined for unbleached, bleached and bleached/dyed tops, these tops were then converted into yarns of different twist levels and counts using a worsted spinning system. Some of the bleached yarn from each bleaching method was dyed in a package dye vat to compare the difference of top dyeing versus yarn package dyeing on yarn quality. Fiber diameter, yarn strength, yarn evenness, yarn hairiness and fiber degradation were tested to examine the effects of bleaching and dyeing on these properties at top and yarn stages. A processing route for bleaching and dyeing alpaca fiber was recommended.     

Assessment of the surface roughness of cotton fabrics through different yarn and fabric structural properties

The effects of some yarn properties (i.e. type, count, twist level, ply number, unevenness and crimp) and fabric constructional properties (i.e. cover, thickness and balance) on surface roughness values of cotton woven fabrics were investigated. A general overview of the results showed that surface roughness values of fabrics were affected from yarn and fabric properties and the effects were related to fabric balance, fabric cover (not cover factor), fabric thickness and crimp values of yarns in fabric structures. Surface roughness values of fabrics decreased as yarn fineness and yarn twist levels increased but as yarn ply number decreased. Also, surface roughness values gradually decreased from open-end yarn constituting fabrics to combed yarn constituting fabrics. Results showed that different properties of yarns caused changes in yarn crimps in fabric structure and also governed the changes in fabric balance, as well as changes in roughness of fabric surfaces. The changing properties of yarns and impact of these properties on fabric construction affected the formation of cotton fabric surfaces from smooth to coarse.     

Wicking properties of polyamide 66 twisted nanofiber yarn by tracing the color alteration in yarn structure

In view of the interest in wicking properties of these flexible structures, analysis of the wicking phenomena in nylon 6.6 nanofiber yarns is carried out by considering the twist rate effects. A novel method is used based on adding a pH-sensitive dye to yarn interstructure and the analysis of color alteration of nanofiber yarn structure, resulting from a shift in pH, during the capillary rise of distilled water. The results show that the addition of pH- sensitive dye has no influence on the average nanofiber diameter and the wicking behavior of yarns. This study shows that in short durations, the kinetic of the capillary rise follows the Lucas-Washburn equation. The Lambertw, a mathematical function, has been incorporated, which helps measure an equivalent structural factor of nanofiber yarns and vertical wicking height at any given time considering the gravitational effects. The statistical results show that the average of equilibrium wicking height and capillary rise rate coefficient tend to decrease with increasing the nanofiber yarn twist, due to the reduction of continuity and size of capillaries.     

Dimensional stability of single jersey fabrics of LincLITE® and conventional yarns. I

Dimensional constants (k values) of single jersey fabrics made from LincLITE® and conventional yarns are calculated under dry, steam, full relaxation treatments. Fabrics were made under different tightness factors such as high, medium and low with different twist factors, twist directions and feeder blending. LincLITE® yarns made to get soft and bulkier effects with yarn count of 39 tex and conventional yarns made into 39 tex and 48 tex yarn counts. Various effects on K values are analysed using correlation coefficients. K-values are increased with relaxation progression and have shown some differences between in LincLITE® and conventional fabrics, and feeder blended fabrics. Loop shape factor is highly affected by tightness factor, relaxation and feeder blending in LincLITE® fabrics, whereas twist factor not significantly effects on loop shape factor in conventional fabrics. Stitch density significantly increases with relaxation in conventional fabrics and no significant effect shows with LincLITE® fabrics.     

Continuous twisted nanofiber yarns fabricated by double conjugate electrospinning

In order to fabricate continuously twisted nanofiber yarns, double conjugate electrospinning had been developed using two pairs of oppositely charged electrospinning nozzles. The principle and process of this novel yarn spinning method were analyzed, and the effect of applied voltage, nozzle distance between positive and negative, solution flow rate and funnel rotating speed on the diameters, twist level and mechanical properties of resultant PAN nanofiber yarns were investigated in this paper. The results indicated that electrospun nanofibers aggregated stably and bundled continuously at the applied voltage of 18 kV, the nozzle distance of 17.5 cm between positive and negative, the overall flow rate of 3.2 ml/h and the flow ratio of 5/3 for positive and negative nozzles. The resultant nanofiber yarns had favorable orientation and uniform twist distribution, and the twist level of nanofiber yarns increased with the increase of the ratio of funnel rotating speed and winding speed. The diameters and mechanical properties of nanofiber yarns depended on their twist level. The diameters of prepared PAN nanofiber yarns ranged from 50 µm to 200 µm, and the strength and elongation of PAN nanofiber yarns at break were 55.70 MPa and 41.31%, respectively, at the twist angle of 41.8 °. This method can be also used to produce multifunctional composite yarns with two or more components.     

Comparison of artificial neural network and linear regression models for prediction of ring spun yarn properties. I. Prediction of yarn tensile properties

In this study artificial neural network (ANN) models have been designed to predict the ring cotton yarn properties from the fiber properties measured on HVI (high volume instrument) system and the performance of ANN models have been compared with our previous statistical models based on regression analysis. Yarn count, twist and roving properties were selected as input variables as they give significant influence on yarn properties. In experimental part, a total of 180 cotton ring spun yarns were produced using 15 different blends. The four yarn counts and three twist multipliers were chosen within the range of Ne 20–35 and α _e 3.8–4.6 respectively. After measuring yarn tenacity and breaking elongation, evaluations of data were performed by using ANN. Afterwards, sensitivity analysis results and coefficient of multiple determination (R²) values of ANN and regression models were compared. Our results show that ANN is more powerful tool than the regression models.     

Reducing ring spun yarn hairiness via spinning with a contact surface

In this study, spinning with a contact surface was introduced as a simple and energy-saving method to reduce spun yarn hairiness. Theoretical analysis indicated that yarn hairiness could be reduced via a sufficient long contact surface applied in other part of yarn formation zone in addition to spinning triangle. Then, a simple contact apparatus was installed on ring frame to validate the theoretical analysis. Results proved that yarn hairiness was reduced via a contact surface in the yarn formation zone. However, unevenness was deteriorated for most yarns spun with contact apparatus during the spinning, which might be due to fiber mass concentration. Most of yarns spun with contact apparatus had a lower strength than the conventional yarns. This might be because evenness deterioration to decrease yarn strength overpowered hairiness reduction to increase yarn strength for most yarns spun with a contact surface.     

Exponentially autocorrelated mass distribution along staple fiber yarns

In this work, a series of cotton carded ring-spun yarns of different counts and different twist multipliers is prepared and the mass distribution along the yarns is studied as a random process. The mass autocorrelation coefficients of the coarser yarns are found to be higher as compared to those of the finer yarns and this difference is found to be low at lower twist multiplier of the yarns. The decay of mass autocorrelation at higher distances along the yarns is explained by a double exponential autocorrelation function which raises the probable existence of two highly different random effects that are acting additively on the yarns to decrease the mass autocorrelation at higher distances along the yarns. The finer yarn exhibits faster decay of mass autocorrelation than the coarser yarn, but this difference is low at lower twist multiplier of the yarns.