Compression creep behaviour of polyester needle-punched nonwoven fabrics

This present study deals with the compression creep behaviour of polyester needle-punched nonwoven fabrics. Polyester fibres of three different cross-sectional shapes (round, circular hollow and trilobal) have been selected for this study. An instrument has been designed and fabricated to measure the compression creep property of needle-punched fabrics. The effect of duration of compression load, fabric weight, fibre cross-sectional shapes and reinforcing material on percentage compression creep has been studied. It has been observed that initially, compression creep decreases rapidly and with increase in time, decrease of percentage creep becomes minimal. After about 8500?min of application of the same compression load, no change in compression creep is noticed. The percentage compression creep decreases with the increase in fabric weight irrespective to fibre cross-sectional shapes of polyester needle-punched nonwoven fabrics. Trilobal cross-sectional fabric shows maximum amount of percentage compression creep at all levels of fabric weight followed by round and hollow cross-sectional polyester samples, respectively. The percentage compression creep is higher in case of fabric samples made without reinforcing material compared to the samples with reinforcing material. Hollow cross-sectional polyester fibre can be successfully used as raw material for the preparation of needle-punched nonwoven fabrics with or without reinforcing material carpet or floor mats. However, normal round cross-sectional polyester fibre only with reinforcing material can be used for the said application. Compression creep values of these selected polyester needle-punched fabric samples are much lesser in comparison with commercial market polypropylene needle-punched carpet samples.     

Characterization of needle-punched nonwoven fabrics for industrial air filter application

Needle-punched nonwoven fabrics with three different areal weights have been developed using micro-denier (0.8 Denier) and fine-denier (3 and 6 Denier) staple polyester fibers, separately. Process parameters such as punching density and depth of penetration have been changed according to the fabric areal weight. Effect of fiber fineness and areal weight on air permeability, tensile strength, bursting strength and compressibility of the fabric has been analyzed. It has been observed that air permeability decreases with the increase in areal weight of the nonwoven. The micro-denier fiber nonwoven gives 40% lower air permeability as compared with fine-denier fabrics. 6 Denier nonwoven provides 44% higher tensile strength as compared to 0.8 Denier nonwoven fabric and 23% higher tensile strength than 3 Denier fabrics. Compressibility and compression recovery of 6 Denier fabrics are also better as compared with other fabrics. However, micro-denier fabric shows 24% improvement in bursting strength and very good air dust filtration efficiency.     

Compression behaviour of jute–polypropylene blended needle-punched nonwoven under wet conditions

The subject of this paper is the compression behaviour of jute–polypropylene blended needle-punched nonwoven under wet conditions. It is essential to know the compression behaviour of the needle-punched fabrics under wet conditions because of its various applications like geotextiles and carpets. Needle-punched fabric samples were prepared based on the three-factor three-level Box–Behnken design of experiment to study the individual as well as interaction effects of process parameters of fabric weight, needling density and blend proportion of jute and polypropylene fibre blend on compression properties under wet conditions. Initial thickness, percentage compression, percentage thickness loss and percentage compression resilience are the compression properties considered. The compression properties under wet conditions were compared with their respective dry conditions. This study reveals that most of the wet samples show a slightly higher value of initial thickness, percentage compression and thickness loss than dry samples, irrespective of processing variables, though for compression resilience value it is vice versa. The effect of blend does not have much influence on percentage compression in wet conditions. There is optimum level of needling density (around 250 punches/cm²) and blend proportions (around 75% polypropylene) for minimum percentage thickness loss of wet fabric under higher fabric weight. The compression resilience increases with increase in the content of polypropylene in the blend of polypropylene and jute. Optimum compression properties (highest percentage compression and compression resilience with minimum percentage thickness loss) can be achieved at fabric weight of 450 g/m² with the combination of around 250 punches/cm² needling density and around 75% polypropylene content.     

Study on needle-punched non-woven fabrics made from shrinkable and non-shrinkable acrylic blends. Part I: compressional behaviour

This paper reports the compressional characteristics of needle-punched non-woven fabrics made from shrinkable and non-shrinkable acrylic blends. The basic idea of this work is to explore the possibility of structural changes in needle-punched non-woven fabrics made from blends of shrinkable and non-shrinkable acrylic fibres, as in case of an acrylic bulked-yarn. The effects of variables, namely fabric mass per unit area, needling density and the proportion of shrinkable acrylic fibre in the blend, on various compression-related properties of needle-punched non-woven fabrics have been studied by relaxing shrinkable component of the fabric, using hot steam treatment. A three-variable factorial design technique proposed by Box and Behnken was used to investigate the combined interaction effect of the above variables on compressional properties of these fabrics. Before steam treatment, the needling density and mass per unit area have significant effect on the compression, recovery and resilience parameters of the needle-punched non-woven fabrics but shrinkable acrylic does not have any significant effect before steam treatment. But after the steam treatment, the proportion of shrinkable acrylic also has considerable effect on these parameters.     

Study on thermal resistance of multilayered fabrics under different compressional loads

In this work, the thermal resistance of multilayered fabric ensembles meant for cold weather conditions were studied under different compressional loads. An instrument has been developed to study the thermal resistance of fabrics under different compressional loads. The instrument consists of a test plate, guard plates and a bottom plate. The test plate and guard plates were assembled together as a single entity, which can be moved up and down with a screw shaft. A load cell was connected to the plate assembly to apply the required compressional load on the fabric specimen. Thermal resistance of multilayered fabrics was studied in the developed instrument under different loading conditions. Single-jersey knitted fabric, needle punched fabric and polytetraflouroethylene (PTFE) coated fabrics were used in the inner, middle and outer layer, respectively. Twenty different multilayered fabric ensembles with the same inner and outer layers were studied. The middle layers, i.e. needle punched nonwoven fabrics, were produced from polyester hollow fibres, with varying linear density of fibre, mass per unit area and punch density. The thermal resistance of multilayered fabrics obtained from the developed instrument was compared with the thermal resistance of instruments, namely sweating guarded hot plate (SGHP) and Alambeta. Regression equations were developed and the contour plots were drawn to analyse the effect of the fibre, fabric and process parameters. ANOVAs were conducted to find the significance of the compressional load, linear density of fibre, mass per unit area and punch density on the thermal resistance of fabrics. It was found that the thermal resistance obtained from the instrument follows the same trend as that of thermal resistance obtained from SGHP and Alambeta. Mass per unit area was found to have significant effect on the thermal resistance of multilayered fabrics under different compressional loads. The effect of punch density decreases with the increase in compressional load on the thermal resistance of multilayered fabrics. The thermal conductivity of multilayered fabrics was observed to increase with the increase in the compressional load.     

An investigation into the effect of fabric structure on the compressional properties of woven fabrics

Lateral compression is one of the most important mechanical aspects of fabrics, which reflects their handle. Fabric compressional features depend on the compressional characteristics of constituent yarns and the fabric structure. In order to consider the effect of fabric structural parameters on its compressional properties, woven fabrics with five different weave patterns (plain, hopsack 2/2, twill 2/2, twill 3/1, warp rib 2/2) were produced with three different nominal weft densities (12, 15, 18 cm^?1). The compressional properties of produced fabrics were evaluated at different pressure values using a conventional fabric thickness tester. It was observed that increasing the weft density leads to decrease in the dissipated compression energy as well as the compressibility of the fabric, while the thickness recovery of the fabric increases. Moreover, the plain woven fabric exhibited the lowest dissipated compression energy and compressibility, while the highest thickness recovery. Besides, at the low pressure level, the fabrics with the lower weft densities demonstrate the higher thickness. By increase in the pressure level, the fabric thickness decreases by decreasing the weft density.     

针刺非织造布渗透性能的探讨

针对针刺非织造布的结构探讨了其渗透机理，并通过非织造布透气性，透水性及在不同法向压力下渗透系数的测试，分析了透气性与透水性的相互关系及法向压力对针刺非织造布渗透性能的影响。     

液氨/交联整理对麻织物性能的影响

 针对液氨和交联整理后大麻、苎麻和亚麻织物触觉风格无法进行定量分析的问题,利用KES-F设备测定液氨/交联整理后3种麻织物在低负荷下的拉伸、弯曲、剪切、压缩及表面摩擦性能等基本力学性能指标。实验表明:液氨处理不仅能够提高麻织物的拉伸功和压缩功回复率,对改善麻织物表面性能也有显著的效果;液氨/交联整理后3种麻织物的弯曲、剪切和表面摩擦性能都有明显的改善,拉伸和压缩性能也明显好于交联麻织物     

土工合成材料在浙江省的生产与应用

着重介绍了各种土工合成材料,如土工编织布、针刺非织造布、塑料排水板、土工模袋等的特性与应用情况。     

Effect of compressibility on heat transport phenomena in aerogel-treated nonwoven fabrics

The heat transport properties observed in nanostructured materials such as aerogel-treated nonwoven fabrics are promoting revolutionary breakthroughs as thermal insulators. This article is focused on the thermal transport characteristics of nonwoven fabrics treated with aerogel for potential uses in thermal protective applications. Highly efficient aerogel thermal blankets are now considered a viable option in applications such as clothing, building, and pipelines. A variety of fiber and fabric structures or finishing parameters influence the functional properties of nonwoven materials. In order to assess the thermal properties of aerogel-treated nonwoven fabrics, the KES Thermolabo II and NT-H1 (plate/fabric/plate method for thermal conductivity, q_max cool/warm feeling, and thermal insulation) was used. Fabrics of higher thicknesses show lower heat conductance and therefore higher thermal insulation properties. It has been found that thermal insulation is also related to the weight and compressional properties of the fabric. To make an insulating material effective, it should have low compression set and high resiliency to make the still air to be entrapped into the fibrous material.     

万能强力测试仪的压缩试验夹具

织物受到平面垂直作用力所产生的反应称为织物的压缩性能。压缩性能通过变化的受压压力与织物厚度的函数关系来表征。织物的舒适性和导热行为与织物厚度和可压缩性密切相关。织物的保暖性也与织物结构中静止空气的含量有关。织物的可压缩性、弯曲、拉伸、剪切和表面特征都是影响织物手感、悬垂性、可缝性及成形性的重要因素。目前,测试织物可压缩性最广泛使用的测试仪器是KES-F测试系统和FAST测试系统。     

Investigation of electromagnetic shielding effectiveness of needle punched nonwoven fabric produced from conductive silver coated staple polyamide fibre

In this paper, electromagnetic shielding effectiveness (EMSE) of needle-punched nonwoven fabric produced from silver-coated staple polyamide fibre having a fineness of 1.7 dtex was investigated. This production was carried out at Automatex needle punching line, which consists of carding, cross lapper and needle punching machine. After production, the surface resistivity measurements of needle-punched nonwoven fabric was carried out in accordance with ASTM D 257-07 standard. The EMSE of the as-produced needle-punched nonwoven fabric was determined using a network analyzer as specified in ASTM D4935-10 in the frequency range of 15–3000 MHz. Electromagnetic shielding test shows that needle-punched nonwoven fabric produced from 1.7-dtex silver-coated polyamide fibre has the highest shielding value of 36.53 dB in the frequency range of 15–3000 MHz. The EMSE of needle-punched nonwoven fabric with fibre fineness of 1.7 dtex increased from 11.00 dB maximum to 36.53 dB in the 15–3000 MHz frequency range. It was seen that as the frequency increases, reflection values of the needle-punched nonwoven fabric decrease at floating mode, while absorption values of the nonwoven fabric increase at floating mode in the frequency range of 15–3000 MHz. EMSE results of the needle-punched nonwoven fabric produced from 1.7-dtex silver-coated staple polyamide fibres were compared to carbon fabric and needle-punched nonwoven fabric made from stainless steel fibres.     

Statistical and ANN analysis of thermal and evaporative resistances of multilayered fabric ensembles

In this paper, thermal and evaporative resistance of multilayered fabrics meant for cold weather conditions have been reported. Polyester hollow fibers of 6 denier and 15 denier were used to produce needle-punched fabrics. Full factorial experimental design was used to produce 30 different needle-punched nonwoven fabrics from two different linear densities of fiber by varying mass per unit area and punch density at three and five different levels, respectively. The needle-punched nonwovens were used as insulative middle layer. Single jersey knitted fabric and polytetrafluoroethylene-coated fabric was used as inner and outer layer, respectively. The multilayered fabric ensembles were evaluated for thermal and evaporative resistance using sweating guarded hot plate (SGHP) system. Regression equations were developed to draw the contour plots and to analyze the effect of different parameters on thermal and evaporative resistance of fabrics. Two independent one-way analysis of variance (ANOVA) were conducted to find the significance of linear density of fiber and effect of inner and outer layers on thermal and evaporative resistance of fabrics. The two-way ANOVA was conducted to analyze the effect of mass per unit area and punch density on thermal properties of fabrics and ‘F’ values were calculated. Mean square values of pure error and lack of fit were studied to analyze the fitness of the developed model for thermal properties of fabrics. An artificial neural network (ANN) model was developed to predict the thermal and evaporative resistance of multilayered fabrics and compared with the experimental values. It has been observed that the ANN model predicts the thermal and evaporative resistance of multilayered fabrics with high degree of accuracy.     

Study on needle‐punched nonwoven fabrics made from shrinkable and non‐shrinkable acrylic blends. Part III: filtration characteristics

This paper reports the filtration behaviours of needle‐punched bulked nonwoven fabrics made from shrinkable and non‐shrinkable acrylic blends. The basic idea of the present work is to explore the possibility of structural changes in needle‐punched nonwoven fabrics made from blends of shrinkable and non‐shrinkable acrylic fibres, as in the case of an acrylic bulked yarn, to improve the filtration behaviour. In Part I and Part II of this series, compressional and transmission characteristics of these fabrics were reported, respectively. The effects of variables, namely fabric areal density, needle punch density and the proportion of shrinkable acrylic fibre in the blend, on various filtration‐related properties of needle‐punched nonwoven fabrics have been studied by relaxing the shrinkable component of the fabric using hot steam treatment. A three‐variable factorial design technique proposed by Box and Behnken was used to investigate the combined interaction effect of the above variables on the filtration properties of these fabrics. The fabric areal density and needle punch density were found to have a significant effect on filtration efficiency as well as pressure drop. The proportion of shrinkable acrylic fibre has little effect on filtration efficiency, but the trends are dependent on the needle punch density.     

Development of acoustic nonwoven materials from kapok and milkweed fibres

Acoustic properties of textile materials have been studied for several decades. But, mostly used materials were synthetic, and hence, they were not eco-friendly in nature. Therefore, an attempt was put forward to try the sound absorption property of natural fibres and their blends by needle-punched nonwoven techniques. Nonwoven fabrics of ideal materials are used as acoustical insulation products because they have high total surface area. The effect of blend proportion of kapok and milkweed fibres with cotton, fabric GSM, bulk density and distance of fabric from sound source on sound reduction of nonwoven fabrics was investigated. The sound reduction increases with increase in blend proportion of kapok and milkweed fibres. A nonwoven fabric of cotton/milkweed 40/60 shows the highest sound reduction potential. As the distance between the fabric and sound sources increases, the sound reduction also increases linearly due to reduction of sound intensity which reduces the transmission of sound through the fabric. There is a positive correlation between fabric GSM and sound reduction and negative correlation between bulk density and sound reduction. Further, the thermal conductivity of nonwoven samples decreases with increase in kapok and milkweed blend proportion due to increase in thickness of samples. Hence, the kapok- and milkweed-blended nonwoven samples provide sound as well as thermal insulation characteristics.     

Simulating the structure and air permeability of needle-punched nonwoven layer

The aim of this article is to study and simulate the structure of needle-punched nonwoven fabrics in order to predict air permeability of nonwoven filters. For this purpose, the Poisson’s random number process has been used to model the random position of fibers in a web. A simple and easy-to-use expression was developed to predict the number of webs in a layer, considering the thickness and areal density of nonwoven fabrics. A 3D model was generated by assembling simulated webs. The GAMBIT meshing software was used to generate the mesh for the Computational Fluid Dynamic (CFD) solver. The outlet pressure of generated model was determined by means of CFD tool. Different types of needle-punched nonwoven fabrics were produced using Polyester fibers with different cross section and counts. The air permeability test was carried out on the samples, and the outlet pressure of each sample were measured and compared with theoretical values. The results showed that the simulated structure is capable to predict the air permeability of nonwoven filters adequately. The main novelty of the model is the ability of simulating the structure and air permeability of multi constituent nonwoven layers.     

Tensile characteristics and stress relaxation analysis of woven fabrics in terms of fabric direction

Abstract

Woven fabrics in various end uses are subjected to tensile loads in different directions, so investigation of the effect of fabric direction on the tensile behaviour and the stress relaxation performance of fabrics is important and needs to be considered. In this study, the tensile and stress relaxation properties of woven fabrics with five various weave structures have been analysed, in different directions. It was concluded that the tensile properties of fabrics such as Young’s modulus, breaking load and elongation and also the work of rupture were significantly affected by the fabric direction and weave structure. Moreover, it was determined that the fabric tensile stress relaxation (%) was considerably affected by the applied strain level, fabric direction and weave structure in the confidence range of 95% and it might well be expressed as a Gaussian function of sample direction.     

形状记忆聚氨酯在非织造织物中的应用

应用涂层工艺,将不同浓度的形状记忆聚氨酯涂覆到非织造织物上,制得具有不同聚氨酯含量的形状记忆聚氨酯非织造织物材料,并对处理前后非织造织物的表面结构、形状回复性、折皱回复性、透气透湿性、强伸力等性能进行了测试。实验结果表明:经形状记忆聚氨酯处理后的非织造织物具有很好的形状记忆功能,提高了非织造织物的抗皱性能;当聚氨酯含量较少时,对形状记忆聚氨酯非织造织物的透湿性没有显著影响,但透气性有明显下降。     

聚乙烯醇-乙烯共聚物纳米纤维增强聚丙烯微米纤维复合空气过滤材料的结构与性能

为提高常规纤维基空气过滤材料的过滤性能,采用熔融共混相分离法制备得到聚乙烯醇-乙烯共聚物(PVA-co-PE)纳米纤维并制成悬浮乳液,将聚丙烯(PP)针刺基材浸渍到悬浮乳液中进行冷冻干燥处理,得到PVA-co-PE纳米纤维增强PP微米纤维骨架复合空气过滤材料。借助傅里叶变换红外光谱仪、扫描电子显微镜、静电电位计、孔径分析仪及滤料综合测试台对过滤材料的结构及性能进行表征。结果表明:当纳米纤维的面密度为9.34 g/m²时,复合空气过滤材料对尺寸为0.3 μm的NaCl气溶胶粒子的过滤效率为99.936%,阻力压降为81 Pa,品质因数为0.091 9 Pa^-1,且复合过滤材料的拉伸强度及拉伸模量相比PP针刺基材均增加50%。     

涤纶纺粘针刺非织造布生产线电气系统设计介绍

介绍了涤纶纺粘针刺法非织造布生产线控制系统的设计,说明了应对生产线设备构成进行了解,通过一系列的电气控制系统设计对生产线设备的控制得以实现.