1a. Objectives (from AD-416)
Objective 1: Enhance and promote cotton’s natural sustainability features in the context of disposable nonwovens applications. Objective 2: Characterize and correlate the relationships among the cotton fiber quality parameters, the nonwovens process-ability, and the final fabric performance characteristics. Objective 3: Develop and optimize hydro-entanglement chemistry and process parameters for cotton fiber and the nonwoven fabrics thus produced. Objective 4: Develop innovative end-use functional technologies that enable increases in the amount and value of cotton used in nonwoven applications. Objective 5: Develop processes for producing nonwoven fabrics from greige cotton.
1b. Approach (from AD-416)
The ultimate goal of this research project is to increase value-added utilization of cotton via development of performance-specific nonwoven products containing cotton. The term "cotton" used here includes cotton lint, ginning motes and linters, comber noils, processing wastes, recycled cotton, and the like. The research approaches broadly involve 1) characterization of fibers and fiber blends to be used; 2) selection of optimum processes and conditions for fiber opening, cleaning, and web formation; 3) selection of appropriate nonwovens production system; 4) evaluation of process and product performances; 5) physical, mechanical and/or chemical modifications of nonwoven products to attain and/or enhance the required functionality; 6) within the scope of the project, determine biodegradability, cost-effectiveness, environmental impact and sustainability of the products produced; and 7) disseminate the research results via publications, technical forums, and technology transfer to industry. Specifically, the research involves developing fiber-processing technology to obtain supply of clean greige/virgin (scour/bleach-less) cotton that is appropriate for the intended end-use application. Most of the existing manufacturers of nonwoven rollgoods do not have the resources, facilities and/or technical expertise to open and clean supply bales of greige cotton(s). It is imperative to develop a protocol that would enable the nonwovens manufacturers to either both open and clean cotton in their in-house facilities or obtain some readily available pre-cleaned cotton. Depending on individual products, we will determine efficient routes for processing cotton into a clean web for downstream processes. SRRC has the equipment, including cotton carding, to thoroughly open and clean virgin cotton and also the resources to procure and process pre-cleaned supply cottons (say, UltrcleanTM cotton). The preferred research focus is on using greige cotton, instead of bleached cotton that currently is primarily used in premium quality nonwovens. However, nonwoven fabrics made with cleaned greige cotton may be satisfactorily scoured and bleached, if necessary. To determine which cotton would be most cost effective for certain specific end-use applications, certain experimental investigations and small-scale industry-like production trials have been planned. They involve studies of the fiber, process and product metrics and their relationships. Research efforts will be redirected to improve any marginal outcomes. In general, carding process will be deployed to form a web for the downstream needle-punching and/or hydroentangling systems of producing nonwoven products. Optimizations of the N-P and H-E processes and products will be sought through planned investigations. Comprehensive testing of in-process products and end-products will be conducted to realistically evaluate the research outcomes. Statistical tools will be used for reliability of the results. Issues concerning the biodegradability, disposability, environmental impact, safety, government/industry-compliance,and cost-analysis will only be conducted to the extent feasible within the scope of the project.
3. Progress Report
This is the first-year report of a new in-house research project that involves a comprehensive nonwoven research program and a massive installation of new equipment. Significant progress has been made in successfully attaining almost all of the planned objectives and goals. All of the new equipment is now fully operational and productive. Numerous experimental studies and trials to optimize the machinery parameters for producing cotton nonwoven fabrics have been conducted. These studies and trials have demonstrated that pre-cleaned raw/greige (non-bleached) cotton indeed can be used for producing nonwoven substrates for many end-use applications, such as wipes, fleece, sheets, etc. The research products are currently being evaluated commercially. Studies conducted to determine the comparative biodegradability (for the life-end disposal) of cotton-based and manufactured-fiber-based nonwoven fabrics have shown that the cotton-based fabrics biodegrade much faster than the others and that their exposure to soil may be a better bet than a landfill for efficient disposal, which may encourage the replacement of synthetic fibers with cotton in certain disposable products. In another study, certain discounted cotton products, such as cotton ginning and processing wastes, were processed at Clemson University and converted into hydroentangled nonwoven fabrics at the Southern Regional Research Center (SRRC) in New Orleans, Louisiana. The preliminary results indicate that these cotton byproducts may also be beneficially utilized in nonwoven products. In another study to improve flame resistance of cotton nonwovens, the function of a less expensive urea additive, compared to the commonly used, three times more expensive diammonium phosphate fire-retardant (FR), was elucidated. The results have been satisfactory. The extensive research efforts devoted to producing mostly greige cotton-based nonwoven substrates have led to the possibility of eliminating the traditional scouring process. This may lead to even more efficient bleaching, possibly by reducing “burden” of the process. Separately, under a CRADA with a U.S. Cotton Producer and Ginner, an experimental study was conducted to determine the effect of fiber properties of pre-cleaned (UltraCleanR) cotton on the nonwovens process and product. The study has demonstrated that, unlike the traditional woven textiles, the fiber properties, within the normal ranges investigated, did not significantly affect properties of the fabrics produced. In addition, the laundering of these hydroentangled cotton fabrics has revealed, for the first time ever, that the fabrics can be repeatedly machine washed and dried for up to 20 cycles, while still retaining most (~80%) of their original mechanical integrity and dimensional stability. In another comprehensive study of application of “quats” or other chemistry to cotton to improve the latter’s ”adherence” and “release” attributes of the anti-microbial agents, a new fundamental information has been obtained in that the greige cotton-based nonwoven fabrics adsorb and retain significantly more quat than similar fabrics that have been scoured and bleached.
Sawhney, A.P., Reynolds, M.L., Condon, B.D., Slopek, R.P., Hui, D. 2010. An Efficient process for producing economical and eco-friendly cotton textile composites for mobile industry. World Journal of Engineering. 7(1):150-153.