Mechanisms of Cleaning of Textile Substrates

The mechanisms of cleaning and removal of impurities from fibrous structures are complex.

Cleaning of textiles involves surface and interfacial phenomena,so surfactants play a viral role in the process.Much of the surface chemistry involved in cleaning of textiles is directly applicable to other areas of textile manufacturing.Water repellant finishing,stain repellant finishing, wetting, emulsifying, dispersing, aggregating, foaming and defoaming all involve generally the same principles as detergency and cleaning.

The three elements of a scouring process are:

The fibrous substrates to be cleaned;

The impurities to be removed;

The bath or scouring formulation

Since the first two elements in the list are very diverse, several different machanisms are involved in scouring.Chemically,substrates can be classified as hydrophobic or hydrophilic depending on polarity of the polymer comprising the fiber.Textile substrates also differ greatly in construction ,and this can affect scouring.Adhesion of soils to textiles is mostly by Van Der Waals forces,so non-polar soils are also more difficult to be removed using aqueous medium than polar soils. Non-polar soils are also more difficult to be removed from hydrophobic substrates such as polyester and polypropylene than from hydrophilic substrates such as cotton and wool. Conversely,hydrophilic soils are more difficult to be removed from hydrophilic substrates than from hydrophobic substrates. The two general types of soils,solid and liquid ,are removed by entirely different mechanisms.

Cleaning of textile materials requires both removal of the soil and suspension of the soil in the bath. Suspension of soil in the bath to prevent its redeposition on the substrate is just as important as removal of the soil in most cases. It may occur by several different mechanisms.

Electrical and steric barriers may be formed.

Small amounts of oily soil may be dissolved into the hydrophobic portions of surfactant micelles.

Emulsification of oily soil in the bath may also contribute to keeping the soil suspended.