Filament Yarns Research Articles

Physiological and Subjective Evaluation of the Rustling Sounds of Polyester Warp Knitted Fabrics

This study evaluates the rustling sounds of polyester warp knitted fabrics using a psychophysiological technique. We generate and record the rustling sounds of three structural types—reverse locknit, double denbigh, and sharkskin—of warp knitted fabrics, all made from 75D polyester filament yarn at the same density. To obtain quantitative information about rustling sounds, Zwicker’s psychoacoustic parameters—loudness( z), sharpness( z), roughness( z), and fluctuation strength( z)—are calculated from sound spectra obtained by FFT analysis. We acquire physiological signals—electroencephalogram, the ratio of low frequency to high frequency (LF/HF) from the power spectrum of heart rate variability, respiration rate (RESP), heart rate (HR)—from fourteen female participants when each sound is presented to them, and they rate seven sensations—softness, pleasantness, comfort, noisiness, annoyance, clearness, and highness—by free modulus magnitude estimation. Loudness( z), roughness( z), and fluctuation strength( z) are highest for the sharkskin and lowest for the reverse locknit. The rustling sound of double denbigh appears to be related to a positive sensation, with the highest softness, pleasantness, and comfort, and the lowest beta wave and LF/HF. On the other hand, the sharkskin sound appears to evoke negative sensations, with the highest annoyance and noisiness and most increasing beta wave, RESP, HR, and LF/HF. Therefore, we conclude that psychoacoustic parameters such as loudness( z), roughness( z), and fluctuation strength( z) affect psychological and physiological responses evoking negative sensations for warp knitted fabric sounds.

3D morphology of cell cultures: A quantitative approach using micrometer synchrotron light tomography

Current issues in both tissue engineering and cell biology deal with cell behavior extensively in 3D. Here, we explore synchrotron radiation micro-computed tomography as a tool for morphological characterization of such 3D cellular constructs, providing micrometer resolution in soft and hard tissues. Novel image processing techniques allowed quantification of local and global cell distributions, cell density, adhesive cell culture surface, and scaffold geometry. For proof of concept, we applied this technique to characterize the morphology of two cell cultures of different phenotypes, namely human dermal fibroblasts and mouse calvarial osteoblast-like cells, both seeded on a polymer multifilament yarn. From 3D visualizations in these case studies, we saw that the fibroblasts spanned between the yarn filaments and in this way encapsulated the yarn, whereas the osteoblast-like cells lined the filament surfaces and did not span between them. Differences found in cell distribution as a function of distance to the median yarn axis and the closest filament surface, respectively, quantified these qualitative impressions gained from 3D visualizations. Moreover, the volume-normalized adhesive surface differed by one order of magnitude between the two phenotypes. Our approach allows quantitative correlation of local scaffold geometry and cell morphology. It can be used to investigate the influence of cell phenotype as well as various biochemical agents on tissue engineering constructs and the behavior of cells in culture.

Laser Fusion to Impart Cohesion to Textured Filament Yarns

The conventional intermingling process uses a high-speed air jet, positioned in the path of the yarn being textured; to create knot-like intermittent entangled nodes (‘nips’ or ‘tacks’) in the textured thermoplastic continuous multi-filament yarn. This paper reports a proof-of-concept research into the use of a pulse laser to fuse such yarns at discrete points at regular intervals along its length to impart cohesion at required frequencies. Pulse frequency and duration, hence the heat intensity, are varied to determine a suitable range of operating conditions. Results from a range of polyester and nylon yarns show that fusing textured filament yarn to create nips is feasible using a pulse laser as an alternative to intermingling by air jets. The multifilament yarn is also modeled to compute the heat flow in the yarn when heated by a pulse laser. This model can be used, as a tool to estimate the heat energy required to fuse a given textured yarn.

Ballistic Penetration of Conically Cylindrical Steel Projectile into Plain-woven Fabric Target – A Finite Element Simulation

This paper gives a finite element model to simulate the entire process of multilayered fabric target perforated by conically cylindrical steel projectile on the basis of the description of the actual structure of fabric considering crimps of warp and weft yarns. Commercially available finite element code Ls-Dyna is incorporated with the Weibull constitutive equations of filament yarns at high strain rate to simulate the ballistic impact response. The projectile and yarns in the fabric are meshed with a eight-node hexahedron element (Solid 164 in Ls-Dyna). From the comparisons of the residual velocities of the projectile, and deformation and damages of the fabric target after ballistic perforation between the experimental results and theoretical ones, it is proven that at the yarn-structural hierarchy, the finite element method with explicit algorithm and code Ls-Dyna could precisely simulate the ballistic impact between the steel projectile and the fabric target. It is also found from calculations that only when the mechanical properties and constitutive equations at a high strain rate are adopted in the finite element model, can the precision of simulation be improved. An interesting and nonintuitive result is that the existence of fabric interspaces between the interweaved yarns could not decrease the kinetic energy absorptions of the fabric target perforated by the projectile under the ballistic impact. The original ideas of this paper are the considerations of the actual structure of multilayered fabric target and the constitutive equations of yarns at a high strain rate in the finite element model. Compared with other papers in this field, the FEM model proposed in this paper can simulate the interaction between the projectile and the multilayered fabric target more precisely in fabric target deformation, kinetic energy absorption, and strain wave distribution. This model can also be extended to other fabric structures and materials under the ballistic impact.

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).

Preparation of Silicon-Titanium-Carbon-Oxygen Fabric/ Mullite Filler/Polytitanocarbosilane Laminates by Polymer Impregnation and Pyrolysis Method

A polytitanocarbosilane (PTC, 20–50 mass%)–xylene solution was infiltrated into a porous, laminated woven fabric of 21–33 vol% Si-Ti-C-O fibers including 26–46 vol% mullite powder (filler) and decomposed at 1000°C in an argon atmosphere. This polymer impregnation and pyrolysis method (PIP) was repeated eight times to produce a laminated composite of 68%–85% of theoretical density. The effects of the polymer concentration and the fraction of mullite filler on the densification rate and microstructure of the layered composite were studied. The pseudoductility of the densified composite, as measured using four-point flexural testing, was caused by buckling after the elastic deformation and was followed by delamination along the direction of the layered fabric. The strength and the energy of fracture were enhanced by controlling the incorporation of mullite filler in the filament yarn (formation of a narrow pore-size distribution) and densification with a low-viscosity PTC solution. The composite with a higher strength provided a higher energy of fracture. The maximum energy of fracture reached 22 kJ/m2 in the composite with 330 MPa of strength in four-point flexure.

Dyeing behaviour of polyester heat‐set at different temperatures: separate and competitive dyeings

Woven polyester upholstery fabrics, comprising multilobal filament yarn warp and textured yarn weft, were heat‐set at different temperatures. The weft of these heat‐set fabrics was dyed at high temperature (130 °C) using dyes of small and large molecular size, respectively, using both separate and competitive dyeing methods. The results show that the difference in dye uptake between substrates heat‐set at immediately adjacent temperatures is higher in competitive dyeings than in separate dyeings. It has also been observed that dye uptake differences are always higher for dyes of large molecular size than for dyes of smaller size.

Commingled and Air Jet-textured Hybrid Yarns for Thermoplastic Composites

Hybrid yarns have reinforcing and matrix-forming filaments combined together in order to reduce the problems associated with high melt viscosity of thermoplastic matrices. Among hybrid yarns, commingled and air-textured yarns, which are produced with air jets have demonstrated high flexibility and good mixing of constituent filaments. Many research findings have been reported on the structure and properties of intermingled and air-textured yarns having low-modulus apparel-grade filaments. The relationships between air jet, filament yarn, and the processing parameters are critically reviewed. It is emphasized that there is an immediate need to study the mixing behavior of combination of high- and low-modulus filaments in air jet, which has not been investigated in detail in the published literature, in order to improve the mixing of these filaments. The methods used to characterize hybrid yarns are discussed. The need to study and improve the stability of the hybrid yarns in terms of maintaining the level of mixing of constituent filaments across the cross section is also established.

A comparison of the interfacial, thermal, and ablative properties between spun and filament yarn type carbon fabric/phenolic composites

In the present paper, the interfacial, thermal, and ablative properties of phenolic composites reinforced with spun yarn type carbon fabrics (spun C/P composite) and filament yarn type carbon fabrics (filament C/P composite) heat-treated at 1100 °C have been extensively compared. The interlaminar shear strength, crack growth rate, and fracture surface were studied to evaluate the interfacial characteristics of the composites using short-beam shear test, double cantilever beam test, and scanning electron microscopy, respectively. The thermal conductivity and the coefficient of thermal expansion were also measured in the longitudinal and transverse directions, respectively. To explore the ablative characteristics of the composites in terms of insulation index, erosion rate, and microscopic pattern of ablation, an arc plasma torch was used. The interfacial properties of the spun C/P composite are significantly greater than those of the filament C/P composite, with qualitative support of fracture surface observations. It has been investigated that the presence of protruded fibers in the phenolic matrix of the spun C/P composite may play an important role in enhancing the properties due to a fiber bridging effect. The longitudinal thermal conductivity of the spun C/P composite is about 7% lower than that of the filament C/P counterpart. It has been found from the ablation test using arc plasma torch flame that the erosion rate is 14% higher than that of the filament C/P counterpart. Consequently, all the experimental results suggest that use of spun yarn type carbon fabrics heat-treated at low carbonization temperature as reinforcement in a phenolic composite may significantly contribute to improving the interfacial, thermal, and ablative properties of C/P composites.

Coatings on Alkali-Resistant Glass Fibres for the Improvement of Concrete

In general, a sizing is shown to significantly affect both the population and size of flaws on the fibre surface by healing effects. Different alkali-resistant glass (ARG) fibres are coated with special polymer dispersions to provide superior alkali resistance and compared with HTA carbon fibres. Durability testing in highly concentrated NaOH-solutions at ambient and elevated temperatures revealed significant reduction of sizing content of the ‘‘as received’’ ARG fibres after short-term testing. Improved durability of the ARG fibres identified by increased sizing retention is achieved by additional coatings. Styrene–butadiene dispersions proved to be most resistant of those tested. The assessment of changes in the fibre surface chemical properties assisted by nanomechanical investigation is essential for understanding the fibre bulk mechanical fracture behaviour. Sizings and coatings on glass and carbon fibres, respectively, and especially on polymer films, were found to significantly influence both tensile strength of alkali-resistant filament yarns and adhesion strength of coated fibres with cementitious matrices investigated by single fibre pull-out. It would be very advantageous if one could predict higher composites strength of fibrereinforced cement by increasing the tensile strength of the reinforcement fibres. A series of coated yarns showed different mechanical behaviour as a separate phase compared with tensile test results, when a few multifilament bundles were only partly impregnated by the cementitious matrix. The chemistry of the glass fibre sizings and their conditions of interaction (dry or wet state) gives rise to a variation of adhesion strength and modified interphases. Finally, the chemistry of the interaction between both sizing and coating with the cementitious matrix, the concentration of the coating, and the mechanical properties of the coatings were found to significantly influence the strength and failure behaviour with a cementitious matrix. A roving pull-out test allows a rough estimation of the failure behaviour for differently sized and coated reinforcement yarns and their interaction with cementitious matrices.

巻返し工程における急激な巻径変化に対応した張力テンサ

In the preparing process for two-for twisting by using a pirn winder, a hysteresis tenser, in which the distance between a pair of permanent magnet discs is compensated, have been used to maintain filament yarn tension in a constant level. By this method, however, it is difficult to compensate abrupt changes of yarn tension. In this report, we have designed the tension control system which is composed of a tension sensor, a tenser device and a personal computer. The tenser device was developed by the use of an electromagnetic coil, a revolving roller coated with magnetic material, and a separate roller to wind yarn in screw. This control system was evaluated as a tension controlled experiment for a pirn winder. As the results of experiments, it is possible for this system to control filament yarn tension within deviation ±3cN to set the tension value 20∼60cN under 200∼600m/min in yarn speed. And we confirmed that this tension control system by using fuzzy theory has excellent tension control ability in transition characteristics for a pirn winder and this system by using PID control theory has excellent stability compared with hysteresis tenser.

BARRIER EFFECT OF WOVEN FABRICS USED FOR SURGICAL GOWNS

Abstract Surgical gowns must have a barrier effect between the sources of infection and the user (i.e. a healthy person), as well as good wearing comfort. They are often made of woven polyester fabrics. Different fabric constructions are available for this purpose; these are evaluated with reference to their barrier properties. We present an optical method of obtaining cross-section figures of woven fabrics. The fabric is cut in warp and weft directions, and embedded perpendicularly in a cylindrical sample carrier using an epoxy resin. After the manufactured samples have hardened, they are smoothened and polished. Subsequently, images of the cross-sections of the fabrics are obtained by using an optical microscope linked to a digital camera and a computer. The images show the microstructure of the woven fabrics, i.e. the size and distribution of the pores in the filament yarn, and between the filament yarns with respect to the fabric weave and yarn density. The porosity is determined by image analysis methods using ImageC ® by Aquinto. The distributions of the width of the pores and of the pore areas are calculated. Pore channels are shown. The results of structural barrier effect are compared with the results of penetration tests. Synthetic blood or particle-loaded liquids containing microspheres comparable with the sizes of bacteria are used. The time necessary to soak the fabric with liquids or the contamination on the back of the fabric is determined.

Continuous Spun-Like Textured Yarn Processed with Various Plied Filaments and Different Stages of Emery Wheels

A new rotor twister is used to fabricate spun-like filament yarns. The raw material, draw-textured yarn (DTY), becomes as the core yarn and the wrapping yarn. During twisting, the core yarn passes through a pair of emery wheels to make the surface hairy. In this experiment, the rotor speed, twist multiplier, number of emery wheels, and denier of the DTY are varied. The effects of these parameters on tenacity, elongation, and hairiness numbers are examined and discussed. Reducing the number of emery wheels increases hairiness but reduces tenacity and elongation. The twist multiplier influences both tenacity and elongation. Increasing the twist multiplier reduces the hairiness numbers but increases yarn strength. In addition, increasing the speed of the emery wheels under fixed processing conditions increases hairiness but also reduces the tenacity and elongation of the spun-like filament yarns.

Analysis of the dimensionless torque in cone drum false twisting mechanism

An investigation of the dimensionless torque in the newly developed cone drum twister texturing mechanism is reported. The cone drum twister is one of the outer surface contacting friction-twisting devices in false-twist texturing. In this cone drum twister, a filament yarn passes over the surface of the cone drum that rotates by the passing yarn without a special driving device. This research is composed of the theoretical analysis of the false twisting mechanism and the experimental analysis at room temperature. The equations have been derived which shows interrelationship of the conical angle of cone drum, the wrapping angle, the drag angle, and the yarn helix angle. Theoretical values of dimensionless torque were calculated and were compared with the experimental results. It is shown that, as the conical angle and the projected wrapping angle increased, the dimensionless torque also increased. But the conical angle was reached to 30.75°, the dimensionless torque decreased.

Modification of the fine structure of heat‐set polyester on dyeing at high temperature

Polyester woven fabrics for upholstery comprising multilobal filament yarn warp and textured yarn weft have been heat‐set at different temperatures and then dyed at high temperature (130 °C) using dyes of small and large molecular size, in order to study the influence of dyeing on the fine structure of the fibre. The heat‐set substrates have also been blind dyed under the same conditions for comparison. The modification of the fine structure and the influence of the dye and its molecular size have been evaluated by density/crystallinity, differential solubility and iodine sorption measurement. The results show that the thermal treatment associated with dyeing at 130 °C decreases the differential solubility and the iodine sorption of heat‐set polyester. This is the result of a more compact fine structure and in consequence a degree of supplementary setting in the fabric. This effect is more pronounced in fabrics heat‐set at relatively low temperatures.

Polymer impregnation and pyrolysis (PIP) method for the preparation of laminated woven fabric/mullite matrix composites with pseudoductility

Abstract An ethylalcohol solution containing Si(OC 2 H 5 ) 4 and Al(NO 3 ) 3 with a composition of mullite, 3Al 2 O 3 ·2SiO 2 , was infiltrated into a porous laminated woven fabric of 22–35 vol.% SiC or Al 2 O 3 –SiO 2 fibers and 8–42 vol.% mullite powder (filler). The solution was then decomposed at 500 °C in air. This polymer impregnation and pyrolysis method (PIP) was repeated 20–23 times to produce a laminated mullite matrix composite of 73–79% density. The pseudoductility of the densified composite when tested in four-point bend was caused by delamination cracks. This mechanical property was enhanced by (1) good dispersion of the mullite filler in the filament yarn, (2) large amounts of dispersed filler, (3) formation of weak bonds in the filament yarn from the pyrolysis of the mullite precursor, and (4) lower amounts of mullite precursor-derived amorphous solid. The infiltration of the mullite filler dispersed electrosterically in an aqueous solution into the woven fabric offered significant pseudoductility, but infiltration of the filler dispersed in the ethylalcohol solution of the mullite precursor resulted in a brittle composite.

Solvent‐induced modifications in polyester yarns. II. Structural and thermal behavior

AbstractThe structural and thermal behaviors of polyester yarns treated with trichloroacetic acid–chloroform (TCAC) mixture were investigated by differential scanning calorimetric analysis (DSC), wide‐angle X‐ray scattering (WAXS), infrared spectroscopy (IR), and scanning electron microscopy (SEM). The effects of TCAC treatment on original fine filament (FFP) and microdenier (MDP) polyester yarns and on heat‐set polyester yarns were studied. It was found that the glass transition temperature of TCAC‐treated polyester yarns decreases with an increase in treatment concentration due to the plasticization effect, which is remarkable even at lower treatment concentration. The TCAC treatment on polyester yarns resulted in the formation of new crystallites in the extended noncrystalline domains of PET as well as growth and perfection of these new crystallites and the preexisting crystals. Further, the DSC thermograms revealed that TCAC treatment with 3% concentration could be able to overcome the structural changes in PET produced by heat setting at 180°C. The substantial changes in noncrystalline and crystalline domains observed were related to the mechanical properties of yarns. From the WAXS studies, an increase in crystal size and lateral order of TCAC‐treated polyester yarns was noted. The most distinct changes brought about by TCAC treatment include overall orientation determined by the trans–gauche ratio from IR measurements. The removal of oligomers and smoothening out of the fiber surface by TCAC treatment were observed from SEM studies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1555–1566, 2003

Analysis of a high temperature heater in a false twist texturing process

The production of textured filament yarns by false twist texturing is an important commercial method that requires heating. In this study, the transient two dimensional modeling of the yarn, heated by high temperature heaters in a false twist texturing process was developed in order to investigate the influence of various heating conditions on the yarn temperature distribution and to quantify the relative contribution of thermal radiation to the total heating. The surface temperatures and the residence time of yarns of different diameters were measured and compared with the simulation results. The temperature distribution in the cross-section of the yarns was calculated for various yarn speeds and for different heater temperatures. The temperature difference between the surface and the center of different types of yarns along the heater was found. For a yarn in a heater, energy is transferred from the heater surface to the yarn by both convection and radiation. As the yarn approaches its heat setting temperature, the total heat rate decreases. However, the calculated results show that the relative contribution of radiation increases up to 60% of the total with yarn temperature and diameter.

ヒステリシステンサを用いたフィラメント糸製織準備工程用張力制御システム

In the process of preparing warp yarn by using a sectional warper, washer tensers, in which a pair of disks compensate the friction forces of running yarn, have been used to maintain filament yarn tension in a constant level. By this method, however, it is difficult to compensate abrupt changes of yarn tension. In this report, we have designed the tension control system by method of fuzzy theory which is composed of a tension sensor, a tenser device and a personal computer. The tenser device was prototyped by the use of a direct current motor, a pulley with pieces of permanent magnet, and a cogwheel. This control system was evaluated as a tension controlled experiment for a sectional warper. As the results of experiments, it is possible for this system to control filament yarn tension within deviation ±2cN to set the tension value 20cN under 200m/min in yarn speed. And we confirmed that this tension control system is excellent in transition characteristics and stability in tension control for a sectional warper comparing with two types of traditional tension devices.

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.