Advent of Greige Cotton Non-Wovens Made using a Hydro-Entanglement Process

Abstract

Using greige (scour/bleach-less) cotton, non-woven fabrics have been successfully produced by adopting conventional fiber opening, cleaning and (modified) carding machines followed by cross-lapping, pre/light needling, and hydro-entanglement (HE) on modern commercial machinery and equipment. Using standard test methods and procedures, the fabrics were evaluated for their weight, thickness, burst strength, tensile and tear failures in both machine (MD) and cross (CD) directions, and absorbency. Dimensional characteristics of the fabrics were determined before and after an ordinary wash. Microscopic examinations of the fiber/fabric surfaces before and after various conditions/degrees of H-E were conducted. Results of these preliminary research investigations have shown that a run-of-the-mill greige cotton, processed on a conventional cotton cleaning and preparatory system, can indeed be efficiently processed on the downstream non-wovens production equipment. In addition, it has been shown that different processing conditions, especially the high-pressure (HP) hydraulic energy of the H-E system, have a considerable influence on properties of the fabrics produced. At the nominal fabric production rates deployed in the research trials, pressure greater than 100 bar (at the system’s two HP jet-heads) produces a fabric that is partially hydrophilic: a desirable attribute for many end-use applications of cotton non-wovens. Based on a previous in-house investigation, it seems that the HP (hydraulic energy) at certain levels partly removes some of the greige cotton fiber’s natural hydrophobic defensive membrane (outer-surface barrier) of heavy hydrocarbons, such as waxes, pectins, etc., thus making the fiber/fabric partially hydrophilic. Further, it has been observed that the high water pressures (HP), under otherwise similar processing conditions, tend to fracture some cotton fibers into tiny fibrils, as evidenced by scanning electron microscopy (SEM) images. These ruptured fibers, by way of exposing their inner (hydrophilic) walls, could also partly contribute to the fabric’s improved absorbency at elevated hydraulic energy levels. Furthermore, a rather unique fabric structure, comprising certain well-defined fibrous “strands and channels,” observed at elevated (HP) pressures is also deemed to partly contribute to the greige fabric’s improved wickability.