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United States Department of Agriculture

Agricultural Research Service

Research Project: WOOL AND KERATIN FROM WOOL FOR BIO-BASED VALUE-ADDED PRODUCTS Title: Expanding the utility of the Agricultural Research Service (ARS) process bleaching

Author
item Cardamone, Jeanette

Submitted to: Textile Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 2011
Publication Date: July 11, 2011
Citation: Cardamone, J.M. 2011. Expanding the utility of the Agricultural Research Service (ARS) process bleaching. Textile Research Journal. Available: http://trj.sagepub.com/content/early/2011/06/28/0040517511411969.full.pdf+html.

Interpretive Summary: The classical problems of wool yellowness, itchiness, and shrinkage have been investigated over time to provide wool with a more favorable commercial market outcome and improved consumer acceptance. Chemical bleaching methods have involved conventional alkaline bleaching requiring high temperature and up to one hour exposure to attain a high level of whiteness. Ingredients added to the bath provided higher levels of activation for more sustainable conditions. Conventional shrinkage prevention methods have involved chlorination for physical and chemical alteration of the wool fiber surface followed by application of topical resin. This ecologically unacceptable process was replaced by enzyme treatment for selective digestion of the scales of wool (known to cause felting). The novel ARS Process for bleaching, biopolishing, and shrinkproofing wool was the outcome of research to use the most effective aspects of these practices and to incorporate in-situ activated bleach into the conventional alkaline peroxide bleach bath. Subsequent application of enzyme under controlled conditions biopolished wool without weakening it, while limiting area shrinkage to 3% or less when unprocessed wool fabric can shrink up to 20-30%. The ARS Process was effective to shrinkproof cotton by ARS bleaching alone and was effective for preventing shrinkage of viscose rayon fabric. After ARS Processing whiteness increased to levels surpassing conventional alkaline bleaching and the mechanical properties of the fabrics were preserved. Using increased bleach-bath concentrations parchment wool was created to provide a new fabric of wool with sheerness and strength comparable to organdy fabric. Parchment wool offers the permanent stiffness of a sheer fabric without a topical, nondurable finish application. ARS Processing has opened new market potential for sustainable wool processing.

Technical Abstract: The ARS Process for bleaching, biopolishing, and shrinkproofing wool is a novel alternative to chlorination and conventional bleaching. Consumer acceptance of domestic machine-washable, comfortable wool which can be worn next to the skin will lead to niche-market- potential and competitive, increased, market-share for wool. Innovative research to improve properties and solve the perennial problems of yellowness, discomfort in wear, and poor dimensional stability have involved altering fiber morphology and chemistry without negative impact on wool’s appearance, performance or the environment. Whereas chemical bleaching with alkaline peroxide and shrinkproofing with chlorination have limited economy and ecological acceptance, the ARS Process is chlorine-free and requires near-room-temperature conditions with short exposure times to reach high levels of whiteness, softness, and dimensional stability. The chemo-enzymatic process applied to wool involves a novel bleaching system followed by enzyme digestion. With selective surface smoothing and scale erosion, fiber strength was not negatively impacted, felting shrinkage was limited to 2%, and mechanical properties were retained for wool, wool blends, cotton, and rayon fabrics. To simulate the appearance and physical characteristics of organdy fabric, the Process was applied at high concentration to produce parchmentized wool jersey fabric with permanent stiffness showing 45.5 % increase in sheerness as determined digital image analysis. ARS novel bleaching alone can be effectively and efficiently applied to textile fibers at 30 deg C (86 deg F) to attain high levels of whiteness within 30 minutes with sustainability for low energy and low environmental impact.

Last Modified: 10/20/2014
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