Heat insulation characteristics of high bulk nonwovens

The insulation layer is a vital component in cold weather clothing. Majority of the heat loss from the body is restricted by the insulation layer. Hence, the design of insulation layer is critical for the performance of extreme cold weather clothing. The factors which influence the thermal resistance of nonwovens’ layer are fibre denier, fibre cross-section and bulk density, porosity and thickness of nonwovens. In this study, we try to optimize these parameters for high-bulk thermal bonded nonwovens using solid and hollow polyester fibres of different deniers. The effect of these parameters and their interdependency has been evaluated by suitable statistical analysis with the help of Design expert software. Contribution analysis has been carried out to ascertain the importance of thickness, areal density and fibre denier and shape. Finer and hollow fibres give better thermal insulation than the coarser and solid fibres. Nonwovens have very high porosity, especially the lighter and thinner ones have poor thermal resistance. Finer and hollow fibres due to their superior thermal insulation are ideal choice for making thinner and lightweight extreme cold weather clothing.     

Investigation on sound absorption properties of aerogel/polymer nonwovens

This paper presents an investigation on sound absorption performance of aerogel/polymer nonwoven fabrics. Polyester/polyethylene nonwovens embedded with hydrophobic amorphous silica aerogel were chosen for sound absorption measurements. The sound absorption coefficient (SAC) of single and laminated layers of aerogel nonwovens blankets was tested by Brüel and Kjær impedance tube, the noise reduction coefficient (NRC) was used for numerical analysis. A sound absorption index was developed to analyze the effect of aerogel content on sound absorption ability. The effect of air-back cavities on SAC of single-layer aerogel/polymer nonwoven fabrics was investigated. The results show that there is a decrease in SAC with the increase of aerogel content. It is observed that the NRC linearly increased with the increase of layers for all the samples. It was also found that the air-back cavities result in resonance phenomenon, as the increase in thickness of air-back cavities the peak values of SAC shift toward lower frequencies.     

Liquid sorption behaviour of nonwovens

In this paper, spunbond, meltblown and spunbond–meltblown–spunbond (SMS) nonwovens made from polypropylene are analysed for liquid transport behaviour. The thickness, grams per square metre (GSM), porosity, fibre diameter, fibre orientation distribution and water contact angles of these nonwovens are measured. Vertical wicking with decane using tensiometry and water absorbency and spreading using gravimetric absorbency tester are reported. The equivalent pore radii of the nonwovens are deduced from the vertical sorption experiments using tensiometry. The sorption rate under vertical wicking and water spreading rates are faster along machine direction compared with that in cross‐direction due to preferential fibre orientation. The thickness of the nonwoven, fibre diameter and porosity play a vital role in transporting liquid. Thin nonwovens have poor vertical wicking and spreading rate. SMS web has poor absorbency behaviour mainly due to the inability of its top S‐layer to pull the liquid from the middle M‐layer. The measured water spreading lengths with respect to time are compared to the theoretical ones using a model developed by earlier researchers. This model reasonably predicts the spreading behaviour of nonwovens.     

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.     

基于BP神经网络的非织造材料基复合吸声体吸声系数预测

以涤纶针刺非织造材料和聚丙烯熔喷非织造材料为研究对象,通过实验获得其物理结构参数,并将复合前后非织造材料厚度、面密度、孔隙率和孔径作为BP神经网络的输入项,用于预测吸声体的平均吸声系数,同时通过调节输入神经元个数、传递函数和隐含层个数构建了最佳的BP神经网络预测模型。对非织造材料基复合吸声体的吸声性能进行预测,并与测试结果进行了对比。结果表明,运用BP神经网络可以建立较理想的适用于复合吸声体平均吸声系数预测的模型。     

水刺非织造产品吸液性能的研究探讨

水刺非织造产品的吸液性能是一项非常重要的技术指标,特别是在卫生、洁净、过滤等领域应用时,对产品的吸液性有非常高的要求。简述水刺非织造产品的吸液机理及其吸液性能的测试方法,并从水刺非织造产品的组分、缠结度、织物结构、织物面密度、化学整理等方面分析产品吸液性能的变化规律。     

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.     

Recycling of cotton and polyester fibers to produce nonwoven fabric for functional sound absorption material

Recycled fibers are commonly used in dissimilar applications and one of the most important applications is sound absorption. Recycled fiber nonwovens currently are in greater demands in industries because of their advantages such as low cost, biodegradability, acceptable mechanical and physical properties, and so on. Sound absorption materials, renewable, and eco-friendly nonwovens have been developed using recycled cotton and polyester fibers. This research provides a contribution to the body of knowledge on the sound absorption properties of nonwovens using recycled fibers which contain cotton and polyester by means of spun-laid technique and provides a better understanding of the effects of a number of manufacturing processes on nonwovens noise control performance and also contributes to the wider adoption of nonwovens as sound absorbers. The sound absorption coefficients were measured according to ASTM E 1050 by an impedance tube method. The results revealed that the average of the sound absorption coefficients increased with the thickness of the nonwovens, but decreased with the nonwoven fabric density.     

Influences of moisture absorption and chemical treatments on the resin flow characteristics of natural fibre nonwoven mats

A major challenge for the use of natural fibres in polymeric composites is their incompatibility with commonly used matrices, causing weak interfaces of the final composites. Many surface treatments to natural fibres have been proposed to eliminate or reduce these problems. In this paper, we evaluate the influences of three commonly used natural fibre chemical treatments on the resin flow characteristics of flax fibre nonwoven mats in a vacuum-assisted resin transfer moulding process. The alkalization treatment significantly increases the in-plane permeability and flow anisotropy of the natural nonwoven mat due to changes in fibre diameter, fibre surface tension and mat structure. The effects of silane and acetylation treatments on resin flow are much smaller. It is well known that in comparison with glass fibre, natural fibres can absorb a large amount of moisture from surrounding air. The absorption of moisture causes a considerable reduction in the in-plane permeability of natural fibre nonwoven mats.     

中空桔瓣型高收缩聚酯/聚酰胺6超细纤维非织造布的制备及其性能

针对中空桔瓣型超细纤维非织造布开纤率低、悬垂性差的问题,以高收缩聚酯(HSPET)、聚酰胺(PA6)为原料,通过双组分纺粘水刺技术制备了不同面密度的HSPET/PA6超细纤维非织造布,分析了热收缩处理对非织造布开纤率、悬垂性、柔软度、透气性、过滤效率以及力学性能的影响.结果 表明:当水刺压力一定时,与PET/PA6非织...     

Characterization and analysis of ridge gourd (Luffa acutangula) fibres and its potential application in sound insulation

Ridge gourd, the fruit of Luffa acutangula, is extensively used throughout the world. Nevertheless, there is a dearth of scientific information related to the thermal, mechanical and chemical properties of these fibres to explore its potential application in textile industry. This research work is aimed to characterize the L. acutangula plant and investigate its potential application in sound insulation. The fibres are arranged in a cell like structure, when opened it gives a very lower fibre length of less than 10 mm. The chemical composition of fibres is as like other lignocellulosic fibres having around 64% cellulose, 21% hemicellulose and 10% lignin. The density is of fibre is around 1.46 g/cc and having the average linear density of 432 denier. The nonwovens were produced by blending the L. acutangula fibre with cotton as well polyester fibre webs using layering technique at three different blend proportions and their influence on bulk density, sound insulation, thermal resistivity and air permeability has been analysed. The ANOVA analysis showed that all the properties mentioned above was significantly influenced by the blend proportion of L. acutangula. The nonwoven sample produced from 50/50 blend proportion of cotton/luffa and polyester/luffa samples showed better sound reduction and thermal resistivity compared to other samples. The cell-like structure of luffa combined with low bulk density and higher thickness resulted in better results.     

CuO/聚丙烯/乙烯-辛烯共聚物复合熔喷非织造材料的制备及其吸油性能

为高效经济地处理油品泄漏引起的污染问题,利用聚丙烯(PP)与乙烯-辛烯共聚物(POE)共混后制备复合熔喷非织造材料,然后在其表面负载纳米氧化铜(CuO)进行疏水改性.对改性前后非织造材料的形貌、结构、水接触角、吸油和力学性能等进行测试.结果 表明:负载纳米CuO后,CuO/PP/POE复合熔喷非织造材料的结晶度下降,熔...     

Effects of fibre parameters on the ultraviolet protection of fibre assemblies

Ultraviolet (UV) radiation protection is becoming increasingly necessary for human health, and textiles play an important role. The interaction between UV light and textiles is a complex one, involving fibre, yarn and fabric parameters. In this study, an optical model is presented for examining the influences of fibre parameters on the UV protection offered by a bundle of fibres with a given mass. The effects of mean fibre diameter and fibre type on UV absorption were examined. The model was verified with results of UV–visible diffuse reflectance measurements on natural and synthetic fibres. When the mass of fibres was kept constant, within the measurement range in this study, a bundle of fibres with coarser fibres had a lower UV reflectance than that with finer ones. The model accurately predicted factors influencing UV protection, including fibre diameter, fibre transmittance, porosity and refractive index.     

用于非织造材料的Tencel Lyocell纤维

Lenzing纤维公司开发的Lyocell纤维构成了一个纤维产品系列,用于要求具有吸湿性、纯度、柔软性、强度和生物降解性的各种各样非织造产品.述评了长度短的短纤维(低于20 mm)的特性和制得的织物的性质,重点是如何能利用上述纤维设计高性能非织造材料的重要产品性质.     

The acoustic characteristics of dual-layered porous nonwovens: a theoretical and experimental analysis

The normal incidence sound absorption coefficient of single-layered porous materials predicted using some prediction models is well known. The published acoustic behaviors prediction models, such as Biot model, Zwikker and Kosten model, Delany and Bazley model, and Champoux and Allard model, can give acceptable prediction results by only taking specific flow resistivity and material thickness as independent variables to estimate the normal incidence sound absorption coefficient. However, the existing literature fails to provide proper knowledge regarding the acoustic characteristics of dual-layered porous nonwoven absorbers. So, the aim of this paper was to propose a theoretical acoustic model for dual-layered porous nonwoven absorber and to verify the proposed model experimentally. In theory aspect, the study focused on the extension algorithm of the Zwikker and Kosten model for dual-layered nonwoven absorber. The theoretical analysis of the impact of thickness and porosity of outer and inner layer on sound absorption coefficient was detailed using numerical simulation method. In experiment aspect, we particularly designed 20 dual-layered nonwoven absorbers with four types of meltblown polypropylene nonwoven materials and five types of hydroentangled E-glass fiber nonwoven materials firstly. Secondly, the calculated sound absorption coefficients using the proposed model were compared with the measured ones of the 20 dual-layered nonwoven absorbers at 250, 500, 1000, and 2000?Hz. Experimental results indicate that the measured and the calculated data have very similar trend with the change of thickness, porosity, and the sound frequency, apart from the obvious difference between them at low frequency.     

Sound and thermal insulation properties of flax/low melt PET needle punched nonwovens

Noise pollution is an ever increasing problem in the world because of the industrial revolution. Recently, researchers have begun investigating natural fiber composites as potential materials for the manufacture of sound absorption structures. In this work, flax/low melting point polyester needle punched nonwoven fabrics were manufactured and characterized for sound and thermal insulation applications. Nonwovens were developed by blending flax fibers with low melt PET at three blend ratios (10%, 20%, and 30%) with 7 mm and 10 mm needle penetration depth. The test results showed that there was a decrease in thermal resistance value with increase in low melt PET % and needle penetration depth. The developed nonwovens had better sound insulation value at medium and high frequency. There was no significant change in sound insulation value with increase in low melt PET %.     

SiO2气凝胶/芳纶非织造布复合织物的防护功能

为研究SiO₂气凝胶对芳纶非织造布抗压、阻燃防护功能的影响,以芳纶非织造布为骨架材料,将SiO₂气凝胶施加到芳纶非织造布表面,制备出SiO₂气凝胶混杂芳纶非织造布防护材料。通过扫描电子显微镜对其结构形貌进行表征,借助万能材料试验机对其抗压性能进行分析,最后利用热常数分析仪和火焰手系统,测试并评估了制备的防护材料的阻燃隔热性能。结果表明:SiO₂气凝胶以不同大小的块状、颗粒状填充进入芳纶非织造布纤维间的空隙;SiO₂气凝胶可增强芳纶非织造布的抗压性能,且降低其导热系数;混杂SiO₂气凝胶后芳纶非织造布总的吸收能量值降低,说明SiO₂气凝胶可明显增强芳纶非织造布的热防护效果。     

Characterization and synthesis of polyester and viscose nonwovens fabrics embedded with nanoporous amorphous silica

Supreme thermal insulating properties of fibre composite can fortify its niche as a middle layer for numerous cold wear articles. Aiming to achieve lowest thermal conductivity, two separate nonwoven composites were successfully developed by using polyester and viscose fibres. Both were reinforced separately with in-house synthesized nanoporous amorphous silica via sol-gel processing using Tetraethoxy orthosilicate as a precursor with ambient pressure drying. Both nonwovens with two levels of GSM were subjected to silica sol for synthesis of nonwoven/SiO2 composite followed by solvent exchange, silylation and ambient pressure drying. The resulted structures were analyzed and evaluated for their thermal conductivity, pore size and characterized by The Fourier Transform Infrared spectroscopy and Scanning electron microscopy. Properties of composites were examined and compared to each level and attributes. Significant differences between the parameters were calculated using statistica v7.0. One of composite showed lowest thermal conductivity value 0.028 W/m.K     

高端汽车用非织造布的制造技术

介绍了用于非织造纤网加固的Malimo公司的缝编技术和VLAP公司的垂直成网非织造技术。缝编非织造布适合做汽车装饰材料,而垂直成网非织造布主要用于汽车的隔音隔热件。产品的优良性能使其在高端汽车上的应用有着巨大的发展潜力。