Surface modification of synthetic textiles

Abstract

Due to their hydrophobic nature, textiles composed of polyester fibers are prone to accumulate electrostatic charges and to retain oily stains. Retention of oils may also be paralleled by increased redeposition of particulate soils. Ilydrophilic surface finishes are known to be capable of improving these static and soiling properties. Such durable topical finishes are generally attained by modifying the fiber surface chemically, by depositing preformed polymers, or by forming insoluble polymers from appropriate monomers in situ the fiber, by grafting. Interfacial polymerization tciTjues —— similar to those suggested earlier for wool shrink— proofing -have been investigated in the present work to deposit polyamide, polyurea and polyurethane coatings on texturized woven polyester. The effect of the coating on soiling characteristics was found to be highly dependent on the specific monomers employed. The most significant improvements in soiling characteristics were obtained with a polyamide coating formed via the polycondensation of piperazine and adipoyl chloride. Soil release problems are associated not only with 100% polyester textiles, but also with polyester/cellulosic blends, especially those treated with durable press resins. Anionic copolymers, perfluoroacrylates containing hydrophilic segments and topical finishes composed of combinations of these are the most effective in enhancing the soil release properties of such blends. INTRODUCTION With the continued increase in the use of synthetic fibers and the introduction of easy-care cellulose and synthetic fiber/cellulose blends in the last fifteen years, many investigations have been crried out with the objective of obtaining a better understanding of the soiling and soil release behavior of textiles. Soiling problems on textiles generally arise from the unwanted accumulation of oily and/or particulate materials on the surfaces or interior of fibrous structures. The degree of soil removal during cleaning is a function of the substrate, soil, cleaning method and interactions between these. To achieve soil removal from textiles, the oily and particulate matter must not only be separated from the fiber, but must also be carried away from it in the wash liquor with minimum reattachment to fiber surfaces. Complete soil removal is hardly ever achieved in commercial or home cleaning operations (1). As little as 0.1-0.2% (by weight) of an oily soil is probably sufficient to form a thin layer covering most of the fiber surfaces, particularly on the relatively smooth synthetic fibers.