Mechanisms of Soil Release

Abstract

The detergency mechanisms for oily (liquid) soils and particulate soils are different. The functioning of a soil-release finish depends therefore on several of its properties. Oily-soil detergency involves diffusion of water to the soil-fiber interface and roll-up of soil. Other mechanisms (solubilization, emulsification, soil penetration, etc.) usually do not determine the rate of soil removal. Soil-release agents increase the hydrophilic ity of the fiber surface and enhance diffusion of water and hydration of the soil-fiber interface. Detergency of particulate soil is not dominated by the hydrophilicity of the fibers but depends on the location of the particle and its adhesion to the fiber surface. Soil-release agents can facilitate removal of particulate soil by decreasing adhesion of the soil particles and enhancing diffusion of water and detergent into the particle-fiber interface. Nondurable release agents also release particulate soil by a sacrificial flaking or dissolution mechanism. Problems encountered with soil removal from durable-press finished cotton and possible solutions are discussed.