Chlorination, shrinkproofing wool

In the textile industry, chlorine dioxide is used as a bleaching agent and produces high-quality textile fibers with additional qualities. For example, shrinkproof wool owes its qualities to the reaction of chlorine dioxide with the cross-linking sulfur atoms of the wool. 

Use Manufacture of carbon tetrachloride, trichloroethylene, chlorinated hydrocarbons, polychloro-prene (neoprene), polyvinyl chloride, hydrogen chloride, ethylene dichloride, hypochlorous acid, metallic chlorides, chloracetic acid, chlorobenzene, chlorinated lime water purification, shrinkproofing wool, flame-retardant compounds, special batteries (with lithium or zinc) processing of meat, fish, vegetables, and fruit. For information, refer to the Chlorine Institute, 2001 L St., NW, Suite 506, Washington DC 20036. 

Some combing plants also produce shrink-resistant treated wool-top. The current process incorporates chlorination, and the appHcation of a shrinkproofing polymer. Chlorination is likely to be replaced soon by mote environmentally friendly treatments. 

The detection of shrinkproof treatments is not itself part of damage analysis but it can contribute to clarifying cases of damage. To detect chlorinated wool and Hercosett shrinkproof treatments Bayer has suggested the following staining test ... 

Organochlorine compounds are also found in the wastewater when wool is treated with chlorine in the Her cosett process for shrink-proofing wool. Several shrinkproofing processes that use no chlorine have been devised ... 

Therefore, shrinkproofing processes aim at the modification of the fibre surface either by oxidative or reductive methods, and/or by the application of a polymer resin onto the surface. The most frequently used commercial process (the chlorine/Hercosett process) consists of a chlorination step followed by a dechlorination step and polymer apphcation. The chlorination results in the oxidation of cystine residues to cysteic acid residues in the surface of the fibre, and allows the cationic polymer to spread and adhere to the wool surface. Chlorination produces byproducts (AOX) which appear in the effluent and ultimately may generate toxicity in the whole food chain by being taken up by aquatic organisms. There is therefore an increasing demand for environmentally friendly alternatives. 

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