Fluorinated Soil-Release Agents

Although soil retardants reduce soiling, the deposition of soil onto a textile cannot be entirely prevented. If the textile can be washed, soil-release finishes can facilitate the removal of soil considerably. The term soil release suggests a separation of soil from a fabric immersed in water, but such a spontaneous separation is possible only with liquid oily soils. Solid soils cannot separate spontaneously and require mechanical action for their removal. 

The mechanisms of soil release have been reviewed by Patterson and Grind-staff [66] and by Kissa [23,67]. 

Smith [70] has pointed out that if this mechanism is valid, water should instantaneously assume a low contact angle on fluoropolymers with hydrophilic segments. This conflicts with the observed slow decrease of the water-contact angle on such surfaces, which supports the orientation mechanism. It should be noted that other plausible mechanisms can explain the dual action and the slow decrease of the water-contact angle. 

The additional advantages of the hybrid soil-release polymers are increased dry soil resistance and good soil-release performance when coapplied with selected cross-linking formulations on polyester-cotton blends. In contrast, the soil-release performance of nonfluorinated acrylic polymers deteriorates when coapplied with a durable press finish. Disadvantages of the hybrid soil-release polymers are the higher cost of the fluorochemical moiety and a slower water sorption in cross-linking finishes. 

Examples of fluorine-containing soil-release polymers are shown in Table 

---

Table 13.3 Fluorine-Containing Soil-Release Agents... 

---