Hydroentangled Nonwoven Fabrics Research Articles

Modeling of the Stress-Strain Quality of Hydroentangled Nonwoven Fabrics

Hydroentanglement is a mechanical bonding process designed to produce nonwoven fabrics with appearances and textures that resemble woven and knitted fabrics. Eleven samples of hydroentangled nonwoven fabrics with different compositions and weights were subjected to a series of uniaxial stress-strain tests. Models, ranging from the simple Kelvin to the more complicated Kelvin–Vangheluwe, were fitted to the experimental data to find a generalized and universal model. In this model, a nonwoven fabric was considered a nonlinear viscoelastic material. The combination of Kelvin and Vangheluwe models resulted in an excellent fit to the uniaxial stress-strain curves. The model-predicted results almost overlapped with the experimental data, an indication of its excellent accuracy in predicting the mechanical behavior of nonwoven fabrics.

Interrelationships between cotton fiber quality traits and tensile properties of hydroentangled nonwoven fabrics

Cotton fibers can be used to produce nonwovens suitable for numerous single use applications including hygiene, wipes, and medical products among others. Cotton comprises a relatively small amount of total raw materials used in nonwovens production compared to the synthetic fibers of polyester and polypropylene, but the use of cotton fibers in nonwovens continues to increase due to demand for disposable products containing natural, sustainable, and biodegradable materials. However, the relationship between cotton fiber classification measurements and nonwoven fabric physical and functional properties are not well characterized. A better understanding of the effects of cotton fiber properties on nonwovens fabric properties will facilitate fiber selection for specific end-use applications. In this study, cotton fibers with broad distributions of fiber quality measurements from 10 recombinant inbred lines of a multi parent advanced generation intercross multiparent advanced generation intercross population were harvested and processed in their greige state into hydroentangled nonwoven fabrics of two distinct basis weights. Tensile testing of lightweight nonwovens indicated fiber length and tensile strength at break were positively correlated with fabric strength, whereas micronaire (air permeability of a fiber bundle) was negatively correlated indicating finer fibers contributed to increased fabric strength. Increased strength of heavyweight fabrics was mainly correlated with higher fiber uniformity index. These results suggest that cotton fibers could be selectively sourced based on fiber quality for specific nonwoven applications and establishes alternative market opportunities for cotton fibers classified as inferior and subject to discount pricing in the woven textile market.

Effect of Test Parameters on Sensitivity of Tensile Test Results for Greige Cotton Hydroentangled Nonwoven Fabric

This research is an in-depth study into the tensile properties of hydro-entangled nonwoven fabrics made of greige cotton. The effect of five different testing parameters or sample characteristics, weight, gauge length, speed of testing, angle to machine direction, and specimen width, of hydro-entangled nonwoven fabrics made of greige cotton were correlated with load at break, extension at break, tensile stress at break, tensile strain at break, Young’s modulus, and energy at break. The regression equations with an average r2 of 0.82 demonstrated parameters’ positive and effective influence on tensile properties. The influence order of all testing parameters is gauge length = specimen width > speed. This analysis aims to study the effects of testing parameters or sample characteristics on tensile properties. It is hoped that this study can contribute a better understanding of the relationship between hydro-entangled nonwoven fabric mechanical performance and web formations, potentially promoting greige cotton applications.

Permeability prediction of fibrous porous media by the lattice Boltzmann method with a fluid-structure boundary reconstruction scheme

The D3Q27 lattice Boltzmann method (LBM) combined with the fluid-structure boundary reconstruction (fsBR) scheme and the interpolated bounce back (IPBB) method is extensively evaluated to predict the permeability of nonwoven fibrous porous media. The fsBR-IPBB method transfers digitally defined step-like boundary data, e.g. the three-dimensional structure data obtained by the X-ray computed tomography, to continuous smooth boundary data via level-set functions. It leads to highly accurate calculations despite low lattice resolutions of thin fibers with circular cross-sectional shapes, compared to the conventional half-way bounce back (HWBB) method. The fsBR-IPBB method is first applied to predict the permeability of two different arrays of impermeable circular cylinders and verified by comparing the results with the data in the literature. We then validate the method referring to the numerically and experimentally obtained permeability of six types of nonwoven fabrics prepared by the industrial hydroentanglement process. Finally, the discussion on the applicability and the limitation of the macroscopic correlation models to estimate permeability of porous media is carried out. The results show that although the calculated permeability is in reasonable agreement with the measured one with an error of 8.1–16.3%, analytical or empirical correlation models fail to give the correct trend due to the highly inhomogeneous and anisotropic properties of hydroentangled nonwoven fabrics.

Predicting air permeability and porosity of nonwovens with image processing and artificial intelligence methods

This study was conducted to investigate the relationship between the fiber distribution and the permeability properties of the hydroentangled nonwoven fabrics in terms of air permeability and porosity. The fiber distribution and web properties of the hydroentangled nonwoven fabrics have significant influence on mechanical and physical performance of the finished products. Control of these properties during production, without physical testing, plays an important role in reducing response time to change the process parameters as well as production costs and material waste. In this study, an artificial intelligence method has been developed to predict the porosity and air permeability properties of hydroentangled nonwoven fabrics from their texture features. For this aim, two image processing algorithms were developed in order to measure the fabric porosity and to extract texture statistical features. For the prediction of the investigated fabric properties, an Artificial Neural Network (ANN) model was built. The investigated samples were composed of Polyester (PES) and Viscose (CV) fiber with different areal weights. High regression values were obtained between predicted and actual values for both porosity and air-permeability properties. According to ANN results, it was revealed that the air permeability and porosity properties of hydroentangled nonwovens can be predicted with high accuracy from their texture images.

Development and Characterisation of Nonwoven Fabrics for Apparel Applications

The cost of making apparel fabrics for garment manufacturing is very high because of their conventional manufacturing processes and new methods/processes are being constantly developed for making fabrics by unconventional methods. With the advancements in technology and the availability of the innovative fibre, durable nonwoven fabrics by using the hydroentanglement process that can compete with the woven fabrics in terms of their aesthetic and tensile properties are being developed. In the work reported here, the hydroentangled nonwoven fabrics were developed through a hybrid nonwoven manufacturing processes by using fibrillated Tencel® and bi-component (sheath/core) polyethylene/polyester (PE/PET) fibres, in which the initial nonwoven fabrics were prepared by the needle-punching method followed by hydroentanglement process carried out at optimal pressures of 50 to 250 bars. The prepared fabrics were characterised according to the British Standards (BS 3356:1990, BS 9237:1995, BS 13934-1:1999) and the attained results were compared with those for a standard plain-weave cotton, polyester woven fabric and commercially available nonwoven fabric (Evolon®). The developed hydroentangled fabrics showed better drape properties owing to their flexural rigidity of 252 mg.cm in the MD, while the corresponding commercial hydroentangled fabric displayed a value of 1340 mg.cm in the MD. Tensile strength of the developed hydroentangled fabrics showed an approximately 200% increase than the commercial hydroentangled fabrics. Similarly, the developed hydroentangled fabrics showed higher properties in term of air permeability, such as the developed hydroentangled fabric exhibited 448 mm/sec and Evolon fabric exhibited 69 mm/sec at 100 Pa pressure. Thus for apparel fabrics, the work combining the existing methods of nonwoven production, provides additional benefits in terms of cost, time and also helps in reducing the carbon footprint for the apparel fabric manufacture.

Micromechanics of hydroentangled nonwoven fabrics

The mechanics of nonwoven fabrics is largely dependent on fiber properties, and other physical factors such as structural arrangement and degree of entanglement of the fibers. In this study, modeled and experimental stress–strain behaviors of uniaxially loaded hydroentangled nonwoven fabrics have been analyzed and compared. The theoretical values from the model were deduced from the measured properties of micro-samples, namely, fiber volume faction, orientation distribution and mechanical properties. Testing of the micro-samples was performed on a Deben Microtest Module fitted in the FEI Quanta 200 Scanning Electron Microscope. The experimental stress–strain results show that the structure is in the linear region when the modeled results approach the highest specific stress. Also, the theoretical models highly overestimate the specific stress of the hydroentangled nonwoven fabrics. The results show that the application of the model was limited in predicting tensile stress. Furthermore, a trapezoid method was used to quantify the actual deformation energy from the stress–strain graphs up to the ultimate tensile strength. The theoretical deformation energy was estimated and compared to the experimental values. The model was subsequently modified to improve its predictive capability.

Development of hydroentangled nonwoven fabrics for the protective garments

The aim of this research was to establish the optimum processing conditions for producing hydroentangled nonwoven fabrics best suited for application in disposable and protective wear, such as surgical gowns, drapes and laboratory coats. Carded and cross-lapped webs, from greige cotton, viscose and polyester fibres of three basic weights, were hydroentangled, at three different waterjet pressures on a Fleissner’s Aquajet hydroentanglement machine. An antibacterial agent and a fluorochemical water repellent finish were applied in one bath using the pad-dry-cure technique to impart both antibacterial and water repellent properties to the fabrics. The standard spray ratings, tensile strength and extension at break for three treated and untreated fabrics were evaluated. The spray ratings for the treated fabrics ranged from 80% to 90% against zero for the untreated fabrics while the tensile strengths in both the machine and cross-machine directions of treated fabrics were greater than that for the untreated fabrics, the reverse being true for the extension at break. Contact angles for all treated fabrics exceeded 90° which indicate good resistance to wetting. The finishing treatment decreased the mean pore size of all fabrics and increase in waterjet pressure and fabric weight decreased the air and water permeability. In this study, it was observed that low weight fabrics of 80 g/m2 hydroentangled at low waterjet pressure of 60 bars were suitable for use due to their higher air and water vapour permeability as well as higher pore size distribution. These fabrics meet the requirements for surgical gowns, drapes, nurses’ uniforms and laboratory coats.

Physical and combustion properties of nonwoven fabrics produced from conventional and naturally colored cottons

A comparative study was conducted to identify the effects of processing on physical and combustion properties of needlepunched (NP) and hydroentangled (H-E) nonwoven fabrics produced from fibers of white fiber cotton and a naturally colored brown fiber cotton. A significantly higher degree of flame retardancy (FR) in was observed in fabrics produced from brown cotton fibers compared with white fibers. Calorimetry revealed lower heat release capacity, lower peak heat release rate, and total heat release from brown fibers compared with white fibers. The ash content was also higher in brown fiber samples suggesting higher levels of inorganic elements in the brown fibers. Elemental analyses revealed brown cotton fibers had higher levels of known FR elements including phosphorous and magnesium. The H-E process reduced FR in brown fabrics, which also correlated with a reduction in phosphorous. However, brown H-E fabrics still maintained higher FR than white H-E fabrics. Water content analysis indicated higher water levels in brown fibers, particularly brown greige fibers, which correlated with increased FR. Processing parameters such as energy of H-E did not affect combustion of the two fabric types. Scouring of the brown fiber fabrics reduced, but did not remove coloration, while scouring and bleaching removed the brown color completely. Scouring alone, or scouring and bleaching, completely removed the higher FR properties of the brown fiber fabrics. The results indicate that the mechanism of FR in brown cotton fibers is dependent on multiple compositional factors that may include element content, water content, and compounds related to coloration.

A S tudy of the Factors Affecting the Bursting Strength of Bicomponent Hydroentangled Non - woven Fabrics

This paper presents the bursting strength of hydroentangled non-woven fabrics made from islands-in-the-sea fibers PET/COPET and pie segmented fibers (PA6/PET), and processed using inclined water jet apparatus. The effects of basis weights, water jets pressure and water jets inclination angle on bursting strength of hydroentangled nonwoven fabrics were discussed. The comparison was made on the bursting strength of hydroentangled fabrics of 60 g/m2 and 100 g/m2 processed by using perpendicular water jets at 00 and inclined water jets at 200 with pressure levels of 3bars and 7bars. The results showed that the increases of water jet pressure and basis weight caused an increase of the bursting strength of the hydroentangled fabrics. Furthermore, with increasing of water jets inclination angle, the bursting strength of 100 g/m2 hydroentangled non-woven fabrics were increased while the bursting strength of 60 g/m2 hydroentangled fabrics decreased. Finally the bursting strength of the pie segmented (PA6/PET) non-woven fabrics showed higher bursting strength compared with islands-in-the-sea (PET/COPET) non-woven fabrics. It can therefore be concluded that degree of inclination of the water jet played an important role in hydroentanglement process.

Three-dimensional fiber segment orientation distribution using X-ray microtomography.

The orientation of fibers in assemblies such as nonwovens has a major influence on the anisotropy of properties of the bulk structure and is strongly influenced by the processes used to manufacture the fabric. To build a detailed understanding of a fabric's geometry and architecture it is important that fiber orientation in three dimensions is evaluated since out-of-plane orientations may also contribute to the physical properties of the fabric. In this study, a technique for measuring fiber segment orientation as proposed by Eberhardt and Clarke is implemented and experimentally studied based on analysis of X-ray computed microtomographic data. Fiber segment orientation distributions were extracted from volumetric X-ray microtomography data sets of hydroentangled nonwoven fabrics manufactured from parallel-laid, cross-laid, and air-laid webs. Spherical coordinates represented the orientation of individual fibers. Physical testing of the samples by means of zero-span tensile testing and z-directional tensile testing was employed to compare with the computed results.

Effect of web formation on properties of hydroentangled nonwoven fabrics

The aim of this study was to determine the effects of two popular web-forming technologies, viz., the Rando air-laid technology and the traditional carding and cross-laying technology, on properties of the hydroentangled nonwoven fabrics made therewith. A mill-like fiber processing study was conducted in a commercial-grade pilot plant using a variety of short staple fibers and their blends. The fibers used in the study were greige cotton, bleached cotton, cotton derivatives, and cut-staple polyester. The hydroentangled fabrics produced with the two systems were mainly evaluated for their physical and mechanical properties, absorbency, absorbency capacity, and whiteness. The study has shown that, with the exception of greige cotton linters, the greige cotton lint, greige cotton gin motes, and even greige cotton comber noils, either alone or in blend with the other fibers mentioned, can be mechanically processed into hydroentangled nonwoven fabric structures without any insurmountable difficulties. The drop test and sink time followed each other pretty closely, as the drop test time increased so did the sink times. The "whiteness" of fabric, which is significantly more dependent on the fabric's constituent fiber content than on the fabric's surface-based light reflection, obviously varied considerably. However, the whiteness index within the same fiber types and their blends shows no trend of significant difference between the fabric produced with carded fiber web and the fabric produced with random Rando fiber web. Incidentally, the Rando sample of bleached cotton was not available. Since the nonwoven fabrics of this discussion generally are disposable, the optional use of ‘brighteners’ to improve whiteness of certain whiteness-deficient fabrics may be considered as long as the brighteners do not easily bleed from the fabrics.

Effect of water pressure on absorbency of hydroentangled greige cotton non-woven fabrics

A greige (non-bleached) cotton lint was used to fabricate non-woven fabrics on a Fleissner MiniJet, using different water pressures for the fiber entanglements. The greige cotton and its hydroentangled non-woven fabrics were primarily tested for their hexane extracts (waxes) and water-soluble (sugars) contents using the AATCC TM97 Standard Extraction Test. Tests have shown that a water pressure of 125 Bar or higher almost totally removed the greige cotton’s inherent hydrophobic waxes and water-soluble sugars. This discovery is a significant milestone in the development of greige cotton-based non-wovens because it could change the greige cotton’s native hydrophobic character into a desirable hydrophilic character for many end-uses. In fact, the AATCC Test Method 79-2007 has confirmed that the greige cotton non-wovens fabricated with high water pressure of 125 Bar are absorbent, as indicated by the 1-second time or less it took for the water drop to completely diffuse onto the fabric surface.

The Influences of Hydrophilic Finishing of PET Fibers on the Properties of Hydroentangled Nonwoven Fabrics

Common polyester fibers are hydrophobic in nature. Thus it is hard to process the fibers in the hydroentangled nonwoven process and the resultant nonwoven fabric is hydrophobic as well. In this paper, two kinds of polyester fibers treated with different hydrophilic finishing agents and one common polyester fiber were formed into nonwoven fabrics by using hydroentanglement process. The influences of the hydrophilic and friction properties of the PET fibers on the properties of hydroentangled nonwoven fabrics were studied.

Determination of pore size parameters and its distribution of hydroentangled fabrics by image processing

Some of structural parameters of nonwovens are difficult to quantify. The pores size distribution (PSD) is one of these parameters. The filtration performance of a geotextile is controlled by its pore opening size distribution PSD. Current methods for determining PSD are mostly indirect and contain inherent disadvantages. Recent technological advancements in image analysis offer great potential for a more accurate and direct way of determining the PSD of nonwoven geotextiles. A new and accurate method of image analysis for PSD determination of nonwoven geotextiles is presented in this paper. This method is an efficient and reliable method for determining the PSD and pore size parameters. This method is based on the image analysis. We have used seed growth algorithm for determining the pore size distribution and applied the method to hydroentangled nonwoven fabrics. PSD allows a better understanding of filtration and fluid transportation phenomena through the porous nonwoven fabrics.

Effect of impact force on tensile properties and fiber splitting of splittable bicomponent hydroentangled fabrics

The effect of impact force when using inclined water jets on splittable bicomponents hydroentangled fabrics are investigated focusing on changes in tensile properties and fiber splitting. The results indicated that with increase of impact force, the tensile strength was increased in both machine direction (MD) and crosswise direction (CD). On changing of water jet inclination angle, the tensile strength was the highest at 10 degree followed by 20 degree and the last 0 degree. The highest fiber splitting were observed in pie segment (PA6/PET) followed by island in sea (PA6/COPET) fiber but no fiber splitting was observed for island in sea (PET/COPET) fiber. The impact force in inclined mode of impact, played a great role in improving fiber splitting and tensile properties of hydroentangled nonwoven fabrics. The Scanning Electron Microscope (SEM) photos were used for investigation of fiber splitting by comparing fiber diameter before and after hydroentanglement.

A novel nozzle design for producing hydroentangled nonwoven materials with minimum jet-mark defects

The presence of jet-marks, or jet-streaks, on the surface of hydroentangled nonwoven fabrics, is usually regarded as an undesirable outcome of the hydroentangling process. Jet-streaks degrade aesthetic features and physical properties of the resulting fabrics. Jet-streaks are associated with low tear strength along the machine direction and non-uniform appearance. Reducing or eliminating the occurrence of jet-streaks will lead to increased use of this class of fabrics in many applications. Hydroentangling employs closely-packed single or multiple rows of high-speed waterjets to entangle and consolidate fibers or filaments in a loose (un-bonded) web. In this work, we demonstrated that a waterjet curtain made of two rows of staggered jets where the jets in the 2nd row are smaller in diameter than those in the 1st row can help minimize these jet-marks in a cost-effective manner. The optimal ratio between the diameter of the jets in the 1st and 2nd row depends on the hydroentangling pressure, as well as the web characteristics. In this study, different nozzle diameters ranging from 100 μm to 130 μm for the 2nd row were examined in combination with a fixed diameter of 130 μm for the nozzles in the 1st row. For the type of fiber-web used and the operating pressures considered, a combination of nozzles with 130 μm diameter in the 1st row, and nozzles with 110 μm diameter in the 2nd row, was found to provide the optimum setting for eliminating/minimizing the jet-marks.

Effect of cellulase pretreatment of raw and bleached cotton fibers on properties of hydroentangled nonwoven fabrics

AbstractThis study was undertaken to investigate the effect of enzymatic pretreatment of cotton (polysaccharides) fibers on the properties of resulting nonwoven fabric. Enzymatic treatment is known to improve the esthetical properties of fabrics but will likely lead to a reduction in strength. In the case of nonwovens the strength loss can be even more drastic as cellulase may attack bonded areas of the fabric. In this work, raw and bleached cotton fibers were treated with enzyme solutions prior to fabric formation to avoid possible damage to the bonded areas and improve strength retention. These fibers were first modified with commercially available whole cellulases and monocomponent endoglucanase enzyme solutions. Then they were formed into a fabric and bonded via hydroentangling. Parameters such as bending modulus, fabric tenacity, fiber strength, length and reducing power were measured for each sample. The pretreatment of cotton fibers prior to fabric formation showed that the resulting nonwovens could be stronger and more drapeable than the same fabric composed of untreated fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

A framework for determining the bonding intensity in hydroentangled nonwoven fabrics

The structural changes in the web and the development of bonding in hydroentangled fabrics are considered as a function of the applied energy. A new fundamental expression to characterize the hydroentanglement intensity ( H) is defined as the sum of the deflection depths of all fibre segments subject to the incident water jet impact based on a consideration of the applied energy, fibre dimensions and properties, as well as fibre deformations observed during the process. The influence of fibre rigidity on the hydroentanglement intensity and the relation between the hydroentanglement intensity and fabric tensile strength for different fibres are also considered.

The Impact of Input Energy on the Performance of Hydroentangled Nonwoven Fabrics

The main goal of this study is to investigate the performance behavior of hydroentangled nonwoven fabrics in terms of input water jet energy and fabric structural parameters (basis weight and fiber orientation). The input jet energy was varied by altering jet pressure, number of passes, process speed and fabric basis weight. To achieve the goal, two sets of trials, which had different jet pressures, process speeds, basis weights and number of passes, were executed to reveal the significance of these parameters in achieving high fabric tensile strength. Image analysis was used to determine the fiber orientation of the hydroentangled nonwoven fabrics to aid in understanding fabric performance behavior.