A three-part practical study was conducted on a commercial-grade hydroentanglement system to determine the progressive and cumulative fabric effects of multiple hydroentangling impacts at three different high (hydroentangling) water pressures (HWPs) on classical properties of the resulting nonwoven fabrics made with a substrate of commercially cleaned greige cotton lint. In the first part of the study, the progressive and cumulative effects of a series of four hydroentangling passes (equal to eight hydroentangling exposures or impacts) were studied at a relatively low HWP of 65 bars. In the second and third parts, the progressive and cumulative effects of multiple hydroentanglements at relatively higher HWP(s) of 90 bars and 130 bars were studied. The hydroentangling energy required for the various fabrics (made with the different HWPs and number of hydroentangling passes or impacts) was calculated to assess the overall impact of the energy on the fabric properties. The study has shown that each successive hydroentangling pass and each elevated HWP generally resulted in decreased fabric weight, thickness and air permeability and increased fabric whiteness and water absorbency. The tensile properties of the fabrics, in both the machine direction (MD) and the cross direction (CD), generally increased progressively with each successive hydroentangling pass at the low HWP of 65 bars, but this trend, especially in the CD, was not pronounced at the HWPs of 90 bars and 130 bars, perhaps indicating the attainment of optimum hydroentanglements and hence of tensile properties in the first pass alone at the higher HWPs. The hydro energy imparted to formation of the various fabrics made with the above stated process parameters of interest have shown that the two or four passes of the substrate at the low 65-bar HWP required less energy and yielded greater fabric absorbency compared to the one or two passes of the substrate at (twice) the HWP of 130 bars. On the other hand, only one pass of the substrate at 90 bars and 130 bars yielded greater tensile strength with reduced energy requirement, compared to the four passes at 65 bars. These results show that, depending on the required or preferred fabric properties, the stated hydroentangling process parameters can be considerably manipulated to achieve efficient hydroentanglement and improved energy efficiency.
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