Abstract

A weaving trial with a size-less cotton warp yarn (20/1 Ne) was conducted under mill-like conditions on a modern high-speed, flexible-rapier weaving machine. About 100 yards of a 1/2-twill fabric (64 epi and up to 56 ppi - face down) was produced at speeds up to 500 picks per minute with no warp yarn failure or breakage. This certainly was a very encouraging achievement, which at least demonstrated for the first time ever the "mechanical feasibility" of size-less weaving of 100% cotton yarns on a modern high-speed weaving machine. However, the quality of the fabric produced was not satisfactory, mainly because of the random formation of unsightly, tiny fibrous balls on the fabric surface. The fuzzy ball formation most likely was partly due to abrasion of the warp yarn (yarn-against-yarn and yarn-against-loom-components) and partly due to disintegration of the warp yarn during weaving. The yarn disintegration probably occurred due to some loss of yarn twist by the yarns rapid and repeated extensions and relaxations (i.e., by the so-called yarns up-and-down dancing at a high frequency). Multi-prong efforts to eliminate the referenced fabric defects are continuing. Brief discussions of the weaving trial, weaving performance, and fabric quality comprise this paper.

Introduction

According to a recent Cotton Counts & Customers publication by the National Cotton Council of America, approximately 75% of cotton produced annually worldwide is utilized in the production of value-added, cotton woven fabrics. This obviously makes the weaving sector of textile industry by far the largest market for cotton fiber. The weaving process almost always involves sizing or coating of warp yarns with a suitable adhesive, such as starch, polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), etc.. Sizing strengthens warp yarns to withstand/combat harsh mechanical stresses of weaving process and thus facilitates efficient weaving. Since the sizing ingredients, even the traces thereof, can adversely affect quality of subsequent fabric dyeing and finishing, it is imperative that the sizing chemicals are completely removed from the greige fabric at the first opportunity, and that is done by a wet process called fabric desizing. Since both warp sizing and fabric desizing are very costly, complex, and environmentally sensitive, the cotton textile industry obviously wants to eliminate the underlying process of warp sizing, if at all feasible. At the recommendation of National Cotton Council, the Agricultural Research Service (ARS) of the US Department of Agriculture (USDA) has directed research toward size-free weaving. Thus, for the past 3-4 years, scientists at Southern Regional Research Center have been conducting research investigations to explore the possibilities of reduced sizing and, preferably, size-less weaving (i.e., eliminating warp sizing) in the production of cotton fabrics.

About two years ago, we demonstrated the mechanical feasibility of size-less weaving by weaving, under mill-like conditions, about 100 yards of a relatively low-density twill fabric on a conventional (Draper) fly-shuttle loom without any warp breakage or failure. Although this was a significant milestone, the fly-shuttle loom today is almost obsolete in the American textile industry. Accordingly, the research was redirected to use a modern high-speed weaving machine in the investigation of size-free weaving.

Indeed, it is a great pleasure to report here that we now have produced, for the first time ever, without traditional sizing and without any yarn breakage or failure, another about 100 yards of a cotton twill fabric on a modern high-speed, flexible-rapier weaving machine operating under mill-like conditions. This certainly is a pioneering research development, since no such research accomplishment in size-free weaving of cotton fabric on modern weaving machines has ever been reported. However, in the same breath, we must also report that the fabric quality is not yet fully acceptable. Minor, nep-like (however, soft and fuzzy) balls disrupt the fabric surface. These defects most likely are caused by abrasion or disintegration of warp yarns mostly in the reed-sweep zone. A few yards of the produced fabric apparently do not have as many such defects, which practically demonstrates the feasibility of size-free weaving on a modern high-speed weaving machine. Efforts are continuing to understand the fundamentals of size-free weaving and to determine causes and cures of the fabric defects encountered. This paper briefly covers what we did to achieve what we claim we have.