In the daily work of the laundry shop, the bleaching treatment is a common way of removing stains on shallow or white fabrics. The working principle of the bleacher is adding or removing oxygen from the fabrics to remove stubborn stains: protein-based stains, tannin stains, and dye-based stains, so as to whiten the clothes. For laundry workers, comprehensively knowing the concepts of bleaching can help them determine the safety degree of different bleachers for colored fabrics, and using bleachers correctly is also the key to protecting the fabrics.
The high temperature plays a role as a driver in the bleaching process. The research shows that every time the temperature rises 5.6℃, the chemical effect of the bleacher will double. Take 32.2℃ to 37.8℃ as an example, the chemical effect directly doubles, and the bleaching effect also increases greatly. However, the special chemical properties of bleachers also contain many risks. The quality analysis of the common bleachers in laundry shops is as follows.
Quality Analysis of Common Bleachers in Laundry Shops
- Sodium percarbonate and Sodium perborate
These two kinds of bleachers are moderate bleachers. However, their alkaline nature poses a potential threat to fabrics’ dyes. If they are used for colored silks, the dyes will discolor due to the alkaline environment. Once they are heated, the erosiveness of these bleachers will intensify.
- Sodium hypochlorite
This bleacher is greatly alkaline. Even though it is diluted, it can still remove fabric dyes. As a result, the woolen clothes and silk fabrics should not be bleached with sodium hypochlorite.
- Potassium permanganate
As a strong oxidizing agent, potassium permanganate is bad for colored fabrics. Its acidic nature determines the need for neutralization after its usage to remove the color change brought by bleaching. However, the neutralizing acid will further improve the erosiveness of the bleacher.
- Sodium bisulfite
It is a strong reducing bleaching agent. It is often used to remove the fabric dyes. But its strong effects mean it may do damage to the original colors of the fabrics.
- Titanium Sulfate
As an acid-based reducing bleaching agent, titanium sulfate also does harm to most dyes on the fabrics. People should be careful when using it.
Safe Bleacher
In many bleachers, the 3% hydrogen peroxide is relatively safe. It is composed of two parts of hydrogen and two parts of oxygen. The excess oxygen is exactly the key to safe bleaching. However, many laundry shops mixed hydrogen peroxide with ammonia or protein-based formulations to speed up the bleaching process. This combination will make the erosiveness of the bleacher intensify. The addition of the alkali may also lead to a color change in the colored fabrics.
The Suggested Solution
If people want to use the 3% hydrogen peroxide safely, the spray bottle should be used to achieve partial treatment. Spray hydrogen peroxide for treating cuts and bruises can be bought at the pharmacy’s medicine department.
Slightly spray it at the yellow oxidized stains and other similar stains → put the clothes in an area with good ventilation → naturally air dry
It should be noted that clothes should not be hung around the heat source, and it is prohibited to add other chemical materials to the bleach. If the stains are stubborn, multiple sprays should be done. Although it takes time for the hydrogen peroxide to realize its chemical effect, the laundry workers can do other tasks during this period. The biggest advantage of hydrogen peroxide is that it can be dissolved comprehensively into water after the drying process without additional rinsing or neutralization, which is relatively convenient.
