Location: Cotton Chemistry and Utilization Research
Title: A preliminary study of dyeing greige cotton nonwoven fabrics
with and without traditional scouring and bleaching processes
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: November 2, 2011
Publication Date: April 16, 2012
Citation: Reynolds, M.L., Allen Jr, H.C., Sawhney, A.P., Edwards, J.V., Slopek, R.P., Condon, B.D. 2012. A preliminary study of dyeing greige cotton nonwoven fabrics with and without traditional scouring and bleaching processes. Proceedings of National Cotton Council Beltwide Cotton Conference. 1396-1403.
Interpretive Summary: Use of cotton in nonwoven products historically has been severely limited by the raw fiber’s natural impurities, such as its foreign matter content and its own wax content that makes the fiber hydrophobic, i.e., water repellant. The research at SRRC has demonstrated that a commercially available, mechanically pre-cleaned raw cotton can be successfully processed into hydroentangled nonwoven fabric that is free of the above-stated impurities and hydrophilic (absorbent), as well. This raw cotton-based nonwoven fabric can be satisfactorily dyed without the traditional chemical scouring and possibly even bleaching processes that are costly and eco-sensitive. The elimination of these chemical processes can make cotton fabrics economical, which, in turn, can increase use of cotton in nonwovens.
A previous study conducted at the Southern Regional Research Center had shown that certain processing metrics and conditions of hydroentangling greige (non-bleached) cotton removed almost all of the fiber’s natural hydrophobic impurities, such as the waxes, and made the resulting hydroentangled fabric highly absorbent – the most desired attribute for bleaching, dyeing and/or any special wet-finishing of cotton fabrics. Under the umbrella of this uniquely novel finding, a preliminary study was conducted to convert a mechanically ginned, pre-cleaned cotton lint into two sets of light-weight (~70 g/m2) hydroentangled nonwoven fabrics. One set was produced at the 90 Bar and the other at 135 Bar of hydro-entangling pressure at the machine’s high water pressure heads, while keeping all other processing conditions the same. The fabrics were dyed (and some specially finished for FR and DP attributes) with and without the conventional chemical scouring and/or bleaching processes. The various versions of the treated fabrics, namely the greige, the only-scoured, the only-bleached, the only-dyed (w/o scouring), and the conventionally scoured, bleached and dyed were tested for their typical characteristics, especially their appearance before and after household laundering. The results have shown that the hydroentangled greige cotton nonwoven fabrics made at certain processing conditions are hydrophilic (absorbent) and thus can be satisfactorily dyed without the traditional cotton scouring process and, for some applications, even without the traditional bleaching process. This article briefly describes the properties of the cotton fiber used, the fiber processing metrics involved, and the appearance evaluation of the research products.