Noise pollution is one of the harmful physical sources in the textile industry, which is among those industries that are faced with noise exposure problems. The results of environmental sound measurements at modern textile mills have shown that the sound pressure level varied from 95 to 130 dB, where the highest sound pressure level was at weaving machines. Textile insulation materials can be fitted in order to decrease sound pollution at a low cost. The objective of this work is to design a sound absorber that can be fixed to the body of the machines, at the point of the noise generation, to reduce noise pollution. Poly(lactic acid) (PLA), which is an environmentally friendly material, was used to produce different samples of meltblown nonwoven absorbers to be used for damping the noise of textile machinery. PLA meltblown nonwoven fabric with the areal density of 16.7 g/m2, average fiber diameter of 1.1 µm, mean pore diameter of 9.8 µm and thickness of 0.27 mm exhibited significant sound absorption. The sample with the smallest average fiber diameter among those investigated had the highest damping effect: 23.95, 41.29 and 29.32 dBA at frequencies of 400, 1000 and 1500 Hz, respectively. Our goal is to have a practical tool that accurately evaluates the absorber sound damping under the actual running conditions of the textile machinery. The design of the absorber from one layer of the PLA meltblown nonwoven over a rigid polyurethane foam sheet had an excellent sound absorption property.

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Natural fibers and their waste are widely used all over the world, and their production has been increasing continuously. But, the rubber crumbs from used tire disposal are nonbiodegradable and present significant problems about their end-of-life given a critical environmental impact. These problems require recycling policies to provide the collection and recycling of used clothing, textile wastes, and rubber crumbs. In this work, the acoustic properties of insulator panels from the combination of textile fibers and rubber crumbs material were analyzed. Insulator panels demonstrated a good sound transmission loss (STL) characteristic, especially at high frequencies. The STL of the manufactured panels from a combination of fiber (cotton, wool, and Kapok) and rubber crumbs was investigated at the different sound frequencies. Results indicated that the fiber/rubber crumbs panel had a significant STL profile of 47 dB, 40 dB, and 35 dB, for Kapok, wool, and cotton, respectively. The addition of polylactic acid meltblown nonwoven fabric on the surface of the rubber crumbs side considerably increases the STL by 20%.

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The object of this paper is to investigate the acoustic insulation properties of needle-punched nonwovens produced from recycled polyester waste blended with virgin polyester serving as supportive material. The research work also studies the effect of different processing parameters of needle punching nonwoven machines through the investigation of different needle speeds, lattice speeds, and penetration depths. Throughout the research work, several needles punched nonwoven fabrics were produced under different conditions as follows: Three needle speeds were applied: 280, 245, and 227 rpm. Three lattice speeds were applied: 0.72, 1.47, and 2.35 m/min. Three depths of penetration for the needles were applied: 26, 10, and 5 mm. Finally, different blends of waste/virgin polyester fibers were produced and tested: 40/60%, 20/80%, and 100% virgin polyester. The four parameters investigated had a statistically significant effect on the sound transmission losses obtained. It was proved that as the frequency increases, the needle speed gains importance while the needle penetration depth loses importance. The results of testing the different samples indicated that the highest sound transmission loss is attained using non-woven fabrics produced from virgin polyester fibers and prepared at high stitch density.