Soiling Properties of Wool Fabrics

Abstract

Chemical degradative processes used for shrink proofing treatment improve significantly the soiling properties of wool, presumably by smoothening the fiber surface and increasing its hydrophilic properties. The improvement depends on the level of shrink resistance. Resin-shrinkproofing treatments often impair the good natural soiling properties of wool, depending on the surface energy, hardness, and zeta potential of the resin. Bleaching wool by hydrogen peroxide also improves significantly its resistance to soiling and ease of soil release in wash ing. Reductive bleaching has a slightly lower beneficial effect. Flat-setting treatments with reducing agents also slightly improve the soiling properties of wool fabrics. In order to obtain the optimal soil release properties in washing, the pH of wool and the washing liquor should be > 7. The oil content of wool fibers has an important influence on soiling, increasing soil retention and improving soil release in washing or dry-cleaning. From the point of view of soiling, wool garments should not have more than 0.5% oil content. Due to their strongly hydrophobic properties, water-repellent agents, with the exception of fluorocarbons, significantly impair soiling, desoiling, and soil redeposition in washing. Block copolymers of fluorocabrons and polyethyleneoxides are the only repellents which do not impair the good, natural soiling properties of wool. In fact, they possess a certain degree of soil repettency.