An investigation in structural parameters of needle-punched nonwoven fabrics on their thermal insulation property

The thermal characteristics of hollow polyester fibers were compared with solid polyester fibers in order to study their processing behavior and performance characteristics. The effects of different processing and structural properties including fiber diameter, bulk density of layer, and surface pressure on layers of needle-punched nonwoven fabrics with hollow fibers on thermal resistance properties were also investigated. The results show that hollow fibers have a higher thermal resistance in comparison with solid ones. This is a consequence of air trapping inside the fibers, higher bulkiness, and higher surface area of hollow fibers. Furthermore, thermal resistance of microfibers is better than those of macrofibers in both hollow and solid fibers. The thermal resistance of nonwoven subjected to this study, have an inverted-U-shaped pattern versus the bulk density of the fabric. The results also showed that thermal resistance of needle-punched nonwoven fabrics can be affected by the range of heater temperature during the test, however considerably can be affected by fabric thickness as a main structural property of nonwoven fabrics.     

Ballistic-resistant stainless steel mesh compound nonwoven fabric

The energy of impact must decay and be transmitted after a bullet is shot through a ballistic-resistant cloth with a laminate structure. A rigid net structure transmits the impact stress to reduce the breakage of the material in the direction perpendicular to the fabric after the impacting of a projectile. This work combines the rigid net structure of stainless steel mesh with two layers a needle-punched polyamide nonwoven fabric to create a sandwich-like laminate structure. A compound fabric that is composed of a stainless steel mesh and polyamide nonwoven fabrics is placed in multi-layer Kevlar fabrics, and the buffer effect is measured by performing a dropping weight impact test and a bullet-shooting test. The specifications of the stainless steel mesh and the order of placement of the compound fabrics are varied to show the effect of these parameters on the energy of fracture propagation and the buffer effect of the multi-layered Kevlar compound fabric that includes a layer of compound fabric that is made of stainless steel mesh and polyamide nonwoven fabrics. In this study, the compound fabric replaces several layers of Kevlar unidirectional fabric, to be used to reduce the cost of bulletproof vests without reducing ballistic resistance.     

Studies on compression behaviour of polypropylene needle punched nonwoven fabrics under wet condition

The present study deals with the effect of parallel-laid and cross-laid web of polypropylene needle punched nonwoven fabrics on compression properties (initial thickness, percentage compression, percentage thickness loss and percentage compression resilience) under wet condition. These compression properties of polypropylene needle-punched nonwoven under wet condition have also been compared with its dry condition. With the increase in needling density the initial thickness, percentage compression and percentage thickness loss of the fabrics under wet condition decrease to higher extent compared to its dry condition both in case of parallel-laid and cross-laid fabrics. Cross-laid nonwoven fabric presents lower value of initial thickness percentage compression and thickness loss compared to parallel-laid fabric which is very prominent at high needling density (350 punches/cm²). The percentage compression resilience shows increasing trend with the increase in needling density both under dry and wet conditions of parallel-laid web. It also follows similar trend in case of cross-laid nonwoven under wet condition. The optimum needling density for compression resilience of cross-laid nonwoven fabric under dry condition is 250 punches/cm².     

Sound absorption and viscoelastic property of acoustical automotive nonwovens and their plasma treatment

Sound absorption property, viscoelastic property and the effect of plasma treatment of four automotive nonwoven fabrics on these properties are discussed in this research paper. Needle-punched fabrics used for vehicle headliner include 2 polyester fabrics made of hollow polyester fibers or solid polyester fibers, and 2 polypropylene-composite cellulose fabrics made of jute fibers or kenaf fibers, manufactured with the same web structure of apparent fabric density and fabric thickness. Hollow polyester fiber fabric has the highest sound absorption and the highest loss factor, the second highest is jute fiber fabric. The viscoelastic property is found to be related to the sound absorption property of fabric. The plasma treatment on nonwoven fabrics changes their sound absorption and viscoelastic property as well as their fabric weight and pore size. Hollow polyester fabric shows the increased sound absorption and viscoelastic property after the treatment with the increased pore sizes, while regular polyester fabric displays insignificant changes. The cellulose fabrics are more affected by plasma treatment compared to the polyester fabrics in terms of fabric weight loss and pore size, and jute fabric is more affected than kenaf fabric due to fiber weakness. The jute fabric demonstrates the decreased sound absorption and viscoelastic property, while kenaf fabric shows the increased sound absorption with the unchanged viscoelastic property after the treatment.     

A study of abrasion and frictional behaviour of nonwoven interlining produced with different coating methods

Interlinings are produced recently not only natural and synthetics fibers but also fiber sheet form in nonwoven production methods. During usage, the fabric wears out and because of this problem fabric surface structure deteriorates. As a result of, investigation of fabrics surface and frictional properties has been important before usage of garments. For this reason, a patented laboratory instrument was designed which is based on horizontal working principle of accessing friction coefficient of fibrous textile surfaces. The tested materials were nonwoven interlining materials produced by spunbond methods. Abrasion resistance of paste dot-CoPES nonwoven interlining material is lower than others because of softness handle. On the contrary, friction coefficients have been obtained higher values.     

Study on heat and moisture vapour transmission characteristics through multilayered fabric ensembles

A detailed study on the heat and moisture vapour transmission characteristics of different types of single and multi-layered fabric ensemble by using sweating guarded hot plate (SGHP) has been reported in the present paper. A comparison has been made on thermal and moisture vapour transmission properties of five different insulative fabrics, namely, knitted-raised fabric, needle punched nonwoven, through air bonded nonwoven, spunbonded-through air bonded sandwich nonwoven and warp knitted spacer fabric and three different coated fabrics, namely, plain woven rubber coated, plain woven polyester polymer coated and plain woven polytetrafluoroethylene (PTFE) coated fabric, used for thermal insulation purpose. ANOVA has been conducted to analyse the significance of type of insulative and coated fabrics used. Sandwich nonwoven fabric which has higher thickness and porosity shows higher thermal resistance followed by through air bonded fabric, raised fabric, needle punched fabric and spacer fabric. Spacer fabric shows lesser evaporative resistance due to its lesser thickness and larger aperture size, which increases the diffusion of moisture vapour. Needle punched fabric shows slightly higher evaporative resistance than spacer fabric, followed by raised fabric, through air bonded fabric and sandwich nonwoven fabric. Permeability index of different multilayered fabric ensembles are also compared.     

Compressional fatigue behaviors of air and mechanical folding nonwoven fabrics

The perpendicular-laid nonwoven fabrics may show high loft performance because of the structure composition, which has much fiber oriented in the thickness direction. The ability to maintain the thickness after the cyclic loading is a basic requirement of good high lofts. When the perpendicular-laid nonwoven fabrics are put to practical use as a cushion material, the compressional properties of the cyclic loading should be significant. In this study, a compressional fatigue system has been developed and evaluated with two kinds of perpendicular-laid nonwoven fabrics with different manufacturing processes. The system equation developed provides a stress profile that can be used for analyzing the practical compressional fatigue. The fiber structure of the perpendicular-laid nonwoven fabrics was investigated by using the orientation distribution function (ODF).     

The efficacy of coconut fibers on the sound-absorbing and thermal-insulating nonwoven composite board

The aim of this study is to examine the efficacy of the coconut fiber on the sound absorption and thermal insulation performance towards the composite nonwoven fabrics. The 2D polyester fiber and 12D fire retardant three-dimensional hollow crimp polyester fiber are individually mixed with 4D low-melting point polyester fiber (4DLMf) to produce 2D polyester nonwoven fabric (2D-PETF) and 12D polyester nonwoven fabric (12D-PETF) respectively. Subsequently, the coconut fiber (CF) is then laminated with the 2D-PETF and 12D-PETF to fabricate two types of PET/CF composite boards through the multiple needle-punching techniques. Accordingly, the sound absorption, thermal insulation, Limiting Oxygen Index and relative mechanical properties of the PET/CF composite boards are evaluated properly. The experimental results reveal that both types of PET/CF composite boards possess excellent thermal insulation performance and fire resistance property. Also, for both types of PET/CF composite boards, the average sound absorption coefficient increases with the increased amount of CF.     

Relationship between fiber orientation distribution function and mechanical anisotropy of thermally point-bonded nonwovens

Current efforts to establish links between geometrical features and mechanical performance of nonwoven fabrics in general, and of point-bonded (spot-bonded) nonwovens in particular has been made using the measurements of Fiber Orientation Distribution Function (ODF) and tensile modulus which occurs during controlled-deformation experiments. Image analysis technique (using the Fast Fourier Transform) was used to quantify the fiber orientation distribution. The results suggest that, within a typical window of processing conditions, the fiber orientation has a significant influence on the anisotropical behavior of nonwoven. The data also suggest that mechanical anisotropy of thermally point-bonded nonwovens is likely to be governed by different load transfer mechanism according to the applied macroscopic tensile direction.     

Analysis and construction of a quality prediction system for needle-punched non-woven fabrics

In this study, polyester and polypropylene staple fibers were selected as the raw material, and then processed through roller-carder, cross-lapper and needle-punching machine to produce needle-punched non-woven fabrics. First, the experiment was planned using the Taguchi method to select processing parameters that affect the quality of the needle-punched non-woven fabric to act as the control factors for this experiment. The quality characteristics were the longitudinal and transverse tensile strength of the non-woven fabric as well as longitudinal and transverse tear strength. The L₁₈ (2¹×3⁷) orthogonal array was selected for the experiment as it offered an improvement on the traditional method that wastes a lot of time, effort and cost. By using the analysis of variance (ANOVA) technique at the same time, the effect of significant factors on the production process of needle-punched non-woven fabrics could be determined. Finally, the processing parameters were set as the input parameters of a back-propagation neural network (BPNN). The BPNN consists of an input layer, a hidden layer and an output layer where the longitudinal/transverse tensile and tear strength of the non-woven fabric were set as the output parameters. This was used to construct a quality prediction system for needle-punched non-woven fabrics. The experimental results indicated that the prediction system implemented in this study provided accurate predictions.     

Unprecedented Electromagnetic Shielding Effectiveness of Lightweight Nonwoven Ag/PA66 Fabrics

Novel, high-performance silver coated polyamide, Ag/PA66, nonwoven fabrics with a density of only 0.04 g/cm³ have been developed using staple fibres of 19 (3.3 dtex) and 27 (6.7 dtex) μm diameter. The obtained nonwoven fabrics with an Ag loading of 12-18 wt% exhibited excellent weight-normalised specific electromagnetic shielding effectiveness of over 1200 dB/(g/cm³) in the 0.015-3 GHz range, which is among the highest reported till date. Moreover, the applied microwave was verified to be absorbed rather than being reflected back making the fabrics highly suitable for shielding applications. It was also observed that nonwoven fabrics made from finer 3.3 dtex Ag/PA66 fibres have higher reflection and lower absorption values than their thicker (6.7 dtex) counterparts. Additionally, we have also explored the use of these nonwoven Ag/PA66 fabrics for personal thermal management via Joule heating with samples showing rapid heating response (up to 0.2 °C/sec) and long-term stability measured over 10,000 seconds. The needle-punched Ag/PA66 nonwoven fabrics, in spite of their low density of the order of 0.04 g/cm², exhibited high EMSE values of nearly 69-80 dB, leading to excellent weightnormalised specific electromagnetic shielding effectiveness of over 1200 dB/(g/cm³) in the 0.015-3 GHz range. The production of Ag/PA66 needle punched nonwoven fabrics thus offers a facile route to develop multifunctional fabrics for EMI shielding as well as personal thermal management applications.     

The bioscouring efficiency and activity of alkaline pectinase for cotton fabric

Alkaline pectinases could be applied in the bioscouring for cotton textiles to improve the wettability of the fabric. In order to evaluate the bioscouring effect of cotton fabrics directly and simply, the relationship between the amount of products degraded by alkaline pectinase and the wettability of the fabric was established with spectrophotometry. The results showed that products degraded by an alkaline pectinase Bioprep 3000L exhibited one characteristic absorption peak at 239 nm, which indicated that unsaturated degradation products were yielded. During the bioscouring of the cotton fabrics, the increase of the amount of both unsaturated degradation products and reducing sugars released from the pectins existing in raw cotton fiber was consistent with the improvement of wetting property of the cotton fabrics with prolonging the treatment time.     

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.     

Functional modification of sanitary nonwoven fabric by chitosan/nanosilver colloid solution and evaluation of applicability

For their functional enhancement, sanitary nonwoven fabrics with a relatively smooth surface were treated using chitosan, a natural polymer with excellent biocompatibility, and nanosilver colloid solution, which has strong antibacterial effects even when used in small amounts. The treatment effect was examined at various mixing ratios. When the mixing ratio of the nanosilver solution was higher, antibacterial and deodorization activity was increased. For CH3/NS1 treated fabric, when the mixing ratio of chitosan and nanosilver solution was 3:1, the air permeability was most excellent, and worked as a positive in improving the pleasantness of the sanitary nonwoven fabric. In all samples, the electrostatic propensity was reduced, regardless of the mixing ratio. In terms of the moisture characteristics of chitosan/nanosilver treated nonwoven fabrics, the moisture uptake was found to be superior in the CH3/NS1 treated fabric. When the mixing ratio of the nanosilver solution was higher, moisture permeability decreased, showing a similar tendency to that of air permeability. The vertical water permeability coefficient increased in all treated fabrics. The dynamic water absorption rate was good in CH4 and CH3/NS1 treated fabrics. This means that the absorption of water in the liquid state became easier, thus improving applicability as sanitary nonwoven fabrics.     

Assessing the relationship among fabric constructional parameters, fractional reflectances and cover factors of polyester fabrics by experimental and mathematical methods

This paper focuses on the assessment of the relation among constructional properties, fractional reflectances and cover factors of fabrics woven from polyester yarns. A novel equation for the calculation of the relation between fractional reflectance and fabric cover factor was proposed and the usage of the equation was assessed by reflectance measurements. 48 polyester fabrics having different constructional parameters were used and the fabrics differed from each other by their cover factors. The warp yarn type and count, warp density and warp yarn twist were the same but weft yarn count, weft yarn fiber count and weft density were different for the fabrics in the experimental sub-groups. The reflectance measurements were conducted on the pretreated but undyed fabric samples as well as on the individual yarn systems of the same fabrics. Fabrics with the same cover factors exhibited different fractional reflectances. Reflectances were found to be dependent on the cover factor as well as on yarn fiber fineness, yarn count, yarn density and fabric weave. The changes in crimp of the yarns according to different construction parameters also governed the changes in fractional reflectances of fabric surfaces. The proposed equation was tested according to different fabric construction parameters and it was concluded that fiber fineness and weave pattern were among the most important parameters which govern the total light reflectances from the fabric surfaces, although they are not incorporated in the calculation of the fabric cover factors. The proposed equation was used to explain the effects of these components on the reflectance behavior of the fabric surfaces and on fabric cover.     

Novel measurement for multidirectional fabric wrinkling using wavelet analysis

Measuring and characterizing fabric wrinkling objectively and accurately is of vital importance because wrinkling behavior is one of the most important factors to determine visual aesthetic of fabrics and clothes. In this paper, a novel method for multidirectional fabric wrinkling measurement is presented. 12 fabrics with different fiber contents and weave structures are prepared and wrinkled by the new method. GLCM variables and standard deviation of wavelet decomposition coefficients are used to characterize fabric wrinkling. Results show that WRA (wrinkle recovery angle) does not have significant linear correlation with the GLCM variables (energy, entropy, contrast and correlation). The wavelet coefficient standard deviation at level 6 has the highest correlation with average WRA. The equations between average WRA and standard deviations can be used to predicate average WRA of a fabric conveniently, avoiding the time-consuming and tedious testing of WRA in each direction.     

Flexural stiffness of core spun cotton/spandex weft knitted structures under relaxation and machine washing treatments

In this research work, behavior of flexural stiffness of core spun cotton spandex single jersey, 1x1 rib and interlock fabrics was studied under relaxation and machine washing treatments. Results are compared with similar fabrics made from 100 % cotton. Fabric weight density increased with the progression of treatments and it is proportionate to the fabric tightness factor (stitch length^?1). Even though both types of fabrics had same machine set stitch lengths, cotton/spandex fabrics have shown the higher fabric weight densities than that of 100 % cotton fabrics. Although 1x1 rib and single jersey fabrics knitted with the same machine set stitch lengths, rib fabrics have given higher fabric weight densities than single jersey fabrics. Among the three knitted structures, interlock fabrics with higher machine set stitch lengths gave the higher fabric weights. Fabric stiffness and flexural rigidity have given higher values under the progression of treatments and it was found that higher values of stiffness have given by cotton/spandex knitted fabrics compared to their cotton fabrics. Fabric stiffness and flexural rigidity in wale direction were higher than that in course direction, but it is only observed in single jersey fabrics. However, 1x1 rib and interlock fabrics have shown an opposite behavior. It was also observed a positive correlation between TF (i.e.: stitch length^?1) and bending length/flexural rigidity in both fabric types. Lower flexural rigidities reported with single jersey structures and highest values gave with interlock structures of cotton/spandex and cotton fabrics.     

Dimensional,physical and thermal properties of plain knitted fabrics made from 50/50 blend of modal viscose fiber in microfiber form with cotton fiber

In this study, the dimensional, physical and thermal comfort properties of the plain knitted fabrics made from 50/50 blend of modal viscose fiber in microfiber form with cotton fiber are compared with those of the similar fabrics made from 50/50 blend of conventional modal viscose fiber with cotton fiber and made from 100 % cotton fiber. All the fabric types are produced in three different stitch lengths. The slight differences among the fabric types are observed in terms of the stitch density results and the dimensional constants calculated in the fully relaxed state. In the fully relaxed state, the dimensional K values of the modal microfiber blended knitted fabrics are found to be more closely resemble those of the cotton fabrics rather than those of the conventional modal fiber blended fabrics. The lowest fabric thickness and bursting strength results are obtained for the modal microfiber blended fabrics. The modal microfiber blended fabrics reveal lower air permeability than the conventional modal fiber blended fabrics and higher air permeability than the cotton fabrics. It is also observed from the thermal comfort results that the modal microfiber blended fabrics have the lowest thermal resistance and the highest thermal absoptivity values. The thermal conductivity results of the modal microfiber blended fabrics are lower than those of the cotton fabrics and higher than those of the conventional modal fiber blended fabrics. Because of the highest thermal absorptivity values, the modal microfiber blended fabrics provide the coolest feeling when compared with the other two fabric types.     

Porosity and nonwoven fabric vertical wicking rate

Fabric porosity is the result of fabric constructional parameters combination and used technology of nonwoven production. The effects of fabric porosity structure, as well as the content of hydrophilic viscose and hydrophobic polyester fibres in the web mixture, on the vertical wicking rate by nonwoven fabrics have been explored in this research. Fibrous webs with a different content of viscose and polyester fibres, with the web volume mass range of 0.019-0.035 g/cm³ were utilized during this study. The samples were produced using a dry-laid method of web forming and two methods of web bonding, e.g. needle punching and calendar bonding. Results show that higher volume porosity gives higher vertical wicking rate by all groups of tested samples regarding the content of used hydrophilic/hydrophobic fibres and that fluid flow is faster in samples with larger pores. The higher content of viscose fibres improve the vertical wicking rate, but better rising height can be achieved at samples made from 100 % of coarser polyester fibres. A prediction model of vertical wicking rate of viscose/ polyester nonwovens was developed on the basis of the fundamental constructional parameters of nonwoven fabrics (fibre fineness, type of raw material, and web density) and a non-deterministic modelling method, e.g. genetic algorithms, which can serve as a useful tool for fabric engineers by developing a nonwoven fabric in order to fit desired wicking rate.