Hydrogen Peroxide and Peracetic Acid
Textile and laundry
Hydrogen peroxide is the bleaching agent of choice for the treatment of natural and synthetic fibers such as cotton, wool, rayon, silk, linen and viscose. The high concentration of H2O2 in PERACLEAN® PAA provides the desired bleaching effect on textiles. The use of hydrogen peroxide not only provides a high level of brightness, but also preserves the mechanical properties of the fibers. Peracetic acid is used for disinfection and as a bleaching agent in industrial laundries such as hospitals, hotels and restaurants.
The use of hydrogen peroxide allows not only a high degree of brightness, but also preserves the mechanical properties of the fibers. Similar to pulp bleaching, this process takes place in an alkaline environment. The bleaching liquors have to be stabilized to prevent decomposition reactions due to the presence of trace metals such as copper, iron and manganese, which can often be found in fibers or in water.
Cotton is the main fiber bleached today. Practically all cotton produces nowadays is bleached. About 80-90% of all cotton fabrics are bleached with hydrogen peroxide. Typically, bleaching with 0.3-0.6wt% solutions of hydrogen peroxide at a pH of 10.5-11.5 is carried out for 1-3 hours at a temperature of 90-95 °C. In the past, sodium hypochlorite was commonly used for cotton bleaching. Hypochlorite bleach was, however, abandoned because of high fiber damage and technical difficulties.
Color safe laundry bleaches containing hydrogen peroxide have been accepted by consumers as alternatives to bleaches containing hypochlorite. One of its advantages over chlorine-based bleaches is that it does not affect modern dyes. Evonik’s hydrogen peroxide grades were proven to yield an excellent bleaching performance in hard surface cleaners, laundry prespot products, carpet cleaners and other color safe bleaching products.
For textile and color safe bleaching Evonik recommends using HYPROX® hydrogen peroxide products. For specific requirements we can recommend further grades on request.
Since peracetic acid is a sustainable and skin friendly chemical, it is suitable for disinfection and as a bleaching agent for industrial laundries of hospitals, hotels and restaurants. Especially in the area of textiles that are wear on the body or come into contact with the skin as i n hospital laundry service, skin friendliness is something that needs to be taken into consideration.
Industrial laundries process laundry from hotels, hospitals, nursing facilities, restaurants and food processing plants in continuous-flow washing machines. These washes consist of a series of different compartments in which the linen is treated. The process consists of pre-washing, washing, rinsing, post-treatment and dewatering.
For chemo-thermal laundry disinfection, PERACLEAN® peracetic acid products are used in the washing phase as disinfectants and bleaching agents. The high H2O2 concentration in PERACLEAN® provides the desired bleaching effect. The advantageous ratio of peracetic acid to H2O2 has a positive effect on the stability of peracetic acid in the wash liquid and in some cases allows the amount of disinfectant added to be reduced while maintaining a good bleaching effect.