Friday, January 4, 2013

Textile Finishing; Stain Repellency and Stain Resistant Finishing

There are some textile products or fabric those used long time without any types of wash. So some special care must be taken for those materials. Stain Repellency finishing and Stain-Resistant Finishing are those special treatment whish ensure the proper care of the textile material. This types of finishing also cares from oil and wax. 

Stain Repellency finishing: 
Scotchgard and other finishes that repel water and oil may be classified as stain resistant finishes. These finishes decrease the surface energy of the fabric so that water or oil beads up rather than penetrating the fiber. Illustrates this principle with two different stain-repellent finishes: fluorochemical and silicone. The fluorochemical finish, like DuPont’s Teflon finish on cookware, prevents both oil and water from penetrating the fabric surface. The silicone finish, which also coats the fabric, repels water but not oil.Soil-Release Finishes 

Soil-release finishes were developed largely as a result of the tendency of durable press and polyester fabrics to absorb and hold oilborne stains. The soil-releasing finish should not be confused with stain-repellent finishes, although Scotchgard is both stain resistant and soil releasing. Soil-release finishes alter the characteristics that cause soil to bond to the fibers. Agents such as polyethylene glycol derivatives may be added to the polymer solution before extrusion to make the nonabsorbent fibers more hydrophilic (“water loving” or having a strong affinity to water). Other finishes may form hydrophilic grafts on the fiber resulting in improvements in soil release and soil redeposition. Most soil-releasing finishes are applied during the finishing of the fabric and are compatible with durable pres; finishes. 

Some fluorochemical finishes are dual-acting. They are block copolymers of fluorocarbons and polar segments such as esters. In air the fluorocarbon sections come to the surface to repel oily substances. When the finished fabric is immersed in water, however, the polar hydrophilic sections predominate on the surface, attracting water to help release soils. At the same rime that soil-releasing finishes increase the receptivity of fibers to water, a second benefit is gained. Static electricity buildup is decreased as absorbency is increased. 

Increased absorbency also increases the comfort of the garment in warm weather. Fuzzing and pilling seem to be decreased by soil releasing finishes as well, because the finish also lubricates the fabric. Effective soil-releasing finishes should result in fabrics from which common soil is removed during home laundering with normal detergents. Oily stains, often hard to remove from durable press fabrics, should be removable in home laundering. The disadvantage of most of these finishes is that they are gradually diminished through laundering. 

Stain Resistant Finishing: 
Stain-resistant finishes for nylon carpets were developed to increase the resistance of these carpets to food and other common stains. The finishes are generally sulfonated aromatic condensation (SAC) compounds that function essentially as colorless dyes. The stain blockers, which have negative charges, are attracted to the positive sites in the nylon fibers, tie up the dye sires, and set up a barrier layer to staining materials. Many food stains, for example, which are negatively charged like the stain resist molecules, are not absorbed as easily. Today, stain-resistant finishes are used on most nylon carpets for residential use. One trademark is DuPont’s Stainmaster.

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