Consumers often find peculiar smells when buying denim clothing. There are generally two reasons for this phenomenon: one is that the odor of the black denim fabric itself is not removed in the subsequent washing process; the other is that the chemicals used in the washing process occur Chemical reaction, the peculiar smell remains on the clothing, among which the chlorine bleaching process and the high manganese treatment process are easy to produce the smell.

◆ What impact will the residual odor have on the wearer?

• The black denim fabric is dyed with sulfur dyes. During the dyeing process, alkali sulfide is used as a reducing agent. After dyeing, a small amount of hydrogen sulfide will remain on the fabric surface. A small amount of high-concentration hydrogen sulfide can be fatal in a short time, and low-concentration hydrogen sulfide has effects on the eyes, respiratory system and central nervous system.

• The residual chlorine smell after chlorine bleaching will directly affect the level of clothing, and can also cause mild poisoning of the wearer, mainly manifested as bronchitis, cough, a small amount of sputum, chest tightness, etc. Therefore, after chlorine bleaching, it needs to undergo dechlorination treatment. The quality of the dechlorination effect directly affects the residual odor of the clothing.

• After high manganese rinsing, it needs to be neutralized. Sodium metabisulfite is currently the most widely used neutralizer. Sodium metabisulfite can remove manganese and neutralize only under acidic conditions. The biggest problem during use is that sulfur dioxide gas is easily released during the neutralization process, especially when phosphoric acid is added during potassium permanganate treatment. The cloth surface is very acidic. Strong, the smell becomes more prominent after contact with sodium metabisulfite. There is a smell of sulfur dioxide in the Jiaoya. Sulfur dioxide is a colorless gas with a strong pungent odor, which can cause serious pollution to the atmosphere. It is one of the main components of smog and has become the main monitoring indicator of the national air pollution control; sulfur dioxide Gas is easily soluble in human blood and other viscous fluids, which can cause inflammation of the respiratory tract, bronchitis, emphysema, and conjunctival inflammation. At the same time, it also reduces the immunity of adolescents and weakens disease resistance.

◆ How to get rid of residual odor

1. The residual odor of chlorine bleaching is mainly caused by the insufficient reduction of the chlorine-containing components to sodium chloride after bleaching. The use of appropriate dechlorination agents can effectively reduce the residual odor. For the dechlorination treatment after chlorine bleaching, the common dechlorination agents on the market are sodium bicarbonate and hydrogen peroxide.

Big soda has strong reducibility and can reduce the bleaching water, but after dechlorination, it is easy to leave sulfur on the fabric, causing the fabric to turn yellow; in addition, the dechlorination is not clean, and the treated clothing has a clear smell of chlorine. In addition, the baking soda itself is unstable, and the sulfur dioxide produced after high temperature heating is toxic, which has a strong stimulating effect on the eyes, skin, mucous membranes and respiratory tract, and endangers the health of workers.

Hydrogen peroxide and bleaching water are reductive together, which can reduce the hypochlorite in the solution to salt, thereby achieving the effect of dechlorination. However, due to the weak reducing power, the dechlorination is not clean, the residual chlorine is serious, and the chlorine smell is obvious.

Hongsheng’s chlorine dechlorination agent is a new type of synthetic reducing agent that can replace hydrogen peroxide for dechlorination. It is non-toxic and odorless, which can greatly improve the working environment. It is a processed garment with good whiteness and no yellowing, and there is no residual chlorine and sulfur smell on the fabric

Deodorant is a highly effective odor absorbent developed by Hongsheng specifically for odors such as hydrogen sulfide, mercaptans, sulfides, isovaleric acid and ammonia, which can effectively improve the above-mentioned problem of imperfect dechlorination and obvious residual odor. To

2. The odor residue after high manganese rinsing is mainly caused by the neutralizer itself. The price of sodium metabisulfite is cheap, but if the manganese solution is not clean, it is easy to cause yellowing of the fabric, or if it is not cleaned after the manganese solution, the residual pyrosulfite will generate sulfuric acid, resulting in a decrease in strength, and the pyrosulfite will release sulfur dioxide during use, which is harmful serious. Related companies began to develop and use some alternative products, such as Hongsheng's PP neutralizer. PP neutralizer is a kind of biological metabolite with strong reducibility. It is mainly used for washing and removing manganese after treatments such as hand rubbing with potassium permanganate, frying snowflakes and spraying monkeys in clothing denim. This product is tasteless. The working environment can be greatly improved, and the bleaching effect is better than that of Jiaoya. The garments treated with PP neutralizer have clear flowers, good whiteness, and clean removal of manganese ions.

As long as the green chemicals are selected in the denim washing process, and the appropriate dosage and technology are used, the smell of the clothing can be minimized and the discomfort caused to consumers during the later wearing process can be reduced.