The whitening of textiles

Abstract

Textiles are whitened by the bleaching process. This process is generally applied to grey goods to finish them as white or to fabrics to prepare them for dyeing to pastel shades. Bleaching is a refurbishing step for modern textiles and a conservation/restoration procedure for historic textiles. The bleaching process removes natural colorants, water-borne stains, and oil-borne soils. Throughout history, ubiquitous bleaching practices were carried out in direct sunlight because it became apparent that the sun had a catalytic effect. In the past, bleaching agents had been identified as indigenous acids, bases, and mineral salts. They were applied as soaks and sours to achieve high whiteness levels. Up until the eighteenth century it was common practice to bleach linens and cottons in the sun and woolens in the fumes of burning sulfur. These relatively primitive bleaching practices were not only cumbersome and arduously slow, but required extensive acreage. It was not until the introduction of chlorine-based materials in the late eighteenth century that bleaching became facile. In the late 1920s, hydrogen peroxide became the most prevalent bleach. Since that time, hydrogen peroxide continues to be the prominent bleaching agent for natural fibers and blends with synthetic fibers. Synthetic fibers generally require little bleaching except for size removal, where necessary.