The purpose of soil release finishes is to improve soil removal from hydrophobic of durable press finished fabrics. Soil release does not include detergency of particulate soil but it reduces soil redeposition.
Soiling can be of two types, dry soiling (actual use) and wet soiling (during laundering operations where soil redeposition occurs). Soil is transported to the fabric and then deposited on to it by
- Air currents
- Electrostatic attraction
- Contact transfer from soiled surface to cleaner surface by pressure, abrasion, impingement.
The soil release finishes are available as emulsion, solutions or dispersions and they are either hygroscopic or increase hydrophilicity on water immersion. they also function as antistats. The soil release activity of finish should last for 20-50 home launderings and they should be stable to abrasion. The finish should not be toxic, irritant and should not affect the durablity and wear life of the garment.
The soil release effect may be imparted by a) topochemical reactions such as grafting, hydrolysis or oxidation, b) durable physical adsorption of surfactnats on fibre surface and c) coating with soil release polymers.