USDA-Agricultural Research Service Makes Initiatives in Nonwovens

New Orleans testing lab studies, advances cotton's role

July 2011
From: Nonwovens Industry


The Agricultural Research Service (ARS) of the U.S. Department of Agriculture (USDA) has made a significant investment toward the research and development of mostly cotton-based nonwovens in order to promote value-added, high volume utilization of the natural, renewable and, hence, sustainable cotton fiber. To accomplish this, new, state-of-the-art nonwovens equipment has been installed and commissioned to allow for small-scale production of nonwovens at the ARS-Southern Regional Research Center (SRRC) in New Orleans, LA.In addition, several new and modern textile finishing machines and test instruments have been added to enhance properties and performance of the research and prototype products produced.In addition to the equipment, new scientists and support personnel with extensive academic and industrial experiences have also been added to fully and efficiently utilize the now much expanded research facilities for nonwovens. 

The center already has attracted considerable attention and cooperation from several prominent cotton producers and ginners, commercial nonwovens producers and converters, Delta Council, Cotton Incorporated, National Cotton Council, and academia.Currently, four industrial entities are actively involved in serious collaborative research to develop and produce certain specific-purpose nonwovens of desired functionality. Below you will find a brief description of the Center's nonwovens research facilities; what significant research outcomes have been accomplished in just less than 3 years since the new nonwovens research program began; and what can now be offered to those seeking cooperation and/or collaboration in prototype development and assessment of nonwovens research projects and products, in addition to in-depth discussions, consultations and possible solutions of the real-world challenges. 

The Nonwovens Production, Finishing and Testing Facilities at SRRC 

Equipment for Processing Cotton Fibers into a Nonwoven Fabric Structure Typically, compressed cotton, as received in a bale, is adequately mixed/blended, opened and cleaned (if necessary) and carded on a Crosrol Card (Model MK 4 – Double cylinder card with revolving flats) to produce a continuous web of ~ 10-12 gsm density. [Incidentally, a Saco Lowell nonwovens card and also a Rando webber have been purchased and are awaiting installation.The Rando system will be installed in-line with the existing Fleissner hydroentanglement system to allow for a continuous operation of directly converting cotton fibers, or the blends thereof, into a hydroentangled fabric structure. The addition of these two fiber preparatory systems, viz., the nonwovens card and the webber, will allow greater flexibility to simulate the processes generally adopted by existing nonwoven roll goods producers.In other words, certain cottons for certain nonwoven end-use applications may not need to be prepared and processed in the traditional manner on conventional cotton textile processing equipment.] 

The carded web is continuously fed to a Technoplants Crosslapper (Model CL 10-10L) to multifold the web into a heavier, more condensed batt of desired density (from 40 to 200+ g/m2).The multi-folded lap/batt is continuously fed to a Technoplants Needleloom(Model 80-DUO-10- with two needle boards -one board punches from top and the other from bottom of the web). This machine is used to mechanically interlock constituent fibers of the crosslapped batt (and draft it) to an integrated fabric structure of required weight and construction.

Quite often, a lightly needled cotton (nonwoven) fibrous assembly/structure is fed to a Fleissner Hydroentangling System (Model LaborJet- which is comprised of one pre-wet water jet head; two high-pressure water jet heads for randomly entangling the fibers and thus forming a strong, woven-like fabric; and a gas-fired drum dryer to dry the wetfabric). All of the above mentioned machines in the textile pilot plant are one meter wide, which means the width of the resulting fabric generally is one meter.

Equipment For Special Chemical Finishing 
A number of fabric finishing machines made by Werner Mathis of Switzerland have been installed. They are used to scour, bleach, dye, and/or apply special chemical finishes, such as the flame-retardant, flameproof, antibacterial, resin, durable-press, crease-resistant finishes, etc..These machines are all a half meter wide. Hence, a meter-wide fabric normally produced by the nonwovens equipment generally requires it be cut into half widthwise, in order to accommodate the fabric on these sophisticated machines.

The Werner Mathis lab currently is comprised of the following equipment: 2-Roll Padder; High Temperature Overflow Jet Dyeing Apparatus; Jig Dye Machine; Continuous Oven/Dryer; Laboratory Pad-Steam Range; Electric 2-Roll Calender; Lab Dryer (for small samples); Lab Steamer (for small samples); and chemical preparation area for formulating chemical recipes, etc. 

Textile Testing Equipment and Other Sophisticated Lab Instruments 
A huge variety of textile testing equipment, including the latest versions of Uster, Instron, NIR, HVI, AFIS, EDAX, SEM, TGA, CO2 reactor, and many more., are available at SRRC for conducting the quality and performance characteristics of the 'start-up,' 'in-process,' and 'finished' research materials and products.A number of unique diagnostic and analytical instruments and devices are also available to assess the required attributes of the research products produced. 

Recent Research 
After extensive testing and evaluation, mechanically cleaned virgin/greige (non-bleached) cotton lint has been identified, this greige cotton may not require any additional mechanical cleaning and, hence, can be processed on most existing staple fiber nonwoven lines. The carded web produced from this cotton essentially is free of the plant and/or field contamination that one experiences when processing classical, run-of-the-mill virgin (non-bleached) cotton. 

Hydroentangled fabrics produced using this pre-cleaned virgin cotton fiber are suitable for producing many nonwoven products and no further special processing or fabric modifications may be required. In one of the significant discoveries, certain (optimum) hydroentangling processing parameters have been found, which, during the hydroentangling process itself, will remove the greige cotton's hydrophobic waxes and thus make the cotton fibers hydrophilic without further requiring the costly and environmentally-sensitive wet process of scouring. If an end-use product requires the nonwoven fabric to be pure white, this hydrophilic cotton fabric can be bleached only, i.e., no traditional scouring process is needed. 

A collaborative research project to determine how cotton fiber properties such as micronaire (fiber diameter/fineness), fiber length and length uniformity, will affect the physical and mechanical properties of the hydroentangled fabrics is currently underway.Valuable new information has been obtained from this research. 

Pure cotton and cotton/nylon-film-reinforced "needlepunched fleeces" of great commercial appeal have been produced in sufficient quantity and are presently undergoing encouraging commercial evaluation by certain nonwoven goods manufacturers and by well-known national retailers.' Quaternary Ammonium-based (Quat-impregnated) cotton wipes and eco-friendly antimicrobial cotton wipes are being separately evaluated by different entities. 

Laundering of hydroentangled cotton fabrics has shed significant light on the structure and performance characteristics of such products, which is helpful in seeking new avenues to make such products more durable to repeated/multiple washings. 

A preliminary study of the effluent produced during the process of hydroentangling greige cotton for nonwovens is being applied to determining the feasibility of an improved water filtration system. Contacts with the existing water filtration system dealers have also proved to be useful in the efforts to determine the best possible system commercially available for use in hydroentangling greige cotton. 

One of the ongoing research programs involves medical textiles that encompass wound dressings (both chronic and hemorrhage control), hygienic and decontamination wipes, and incontinence and bedsore prevention materials.State-of-the-art research and development approaches are being utilized to arrive at new proprietary product concepts.Any project seeking surface investigations of nonwoven fabrics may be a good example of research collaboration with the Center.Electrokinetic analysis is one approach that has been found to be particularly effective in understanding the relative hydrophobic/hydrophilic properties of nonwoven fabrics and absorbent structures. 

Offers of Research Collaborations, Product Development, and Consultations 
The Cotton-Based Nonwovens Research Center now can provide a variety of technical services including collaborative research and product development, to the industry and academia.Some of the areas in which the Center can offer help include: 

A cooperative research project involving use of some cotton in a developmental nonwoven fabric/product made with either needlepunch technology or hydroentangling technology or a combination of both the technologies.Depending on their intricacies, some projects may be nominally fee based. 

  • Small-scale, fee-based, fabric production trials with known materials and production metrics/technology. 
  • Feasibility studies followed by actual small-scale production trials of hydroentangling less expensive cotton "non-lint" products (cotton ginning byproducts, cotton textile processing byproducts, discounted cottons, and the blends thereof) have been pursued with satisfactory results 
  • Special chemical finishing of small lots of nonwoven fabrics. 
  • Specific testing and evaluation, including X-ray diffraction, SEM imaging, TGA, and other analytical solutions of nonwoven fabrics. 
  • Visits of the Center's facilities by the industry representatives, academia, and public at large are frequent and encouraged. 
  • Verbal, technical consultations, free of charge, without involving any significant physical work, are also welcome by the Center. 
  • To initiate a dialogue on any project, please contact Brian Condon 504-286-4540; to discuss how the lab could offer help.

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