Rumor: [Dry cleaning black screen] Water washing pretends to be dry cleaning, toxic chemical products... After investigation, it is found that almost all the clothes in xxx and xxx laundries are washed by water; The professional detergent is actually a cheap detergent; The dry cleaning agent is a toxic chemical product, tetrachloroethylene, which can be used to wash, fade, and dye; The charge for a single piece is ten times the washing cost.
Truth: Many media have exposed the "black screen" of the laundry industry, which involves fraud, reasonable prices and other issues beyond the scope of scientific discussion. However, it is worth discussing whether the accusation that "dry cleaning agents make clothes toxic" is reasonable.
What is dry cleaning?
Dry cleaning is relative to water cleaning. Most of our daily cleaning is achieved by using water as a solvent, while dry cleaning uses organic solvents instead of water to clean fabrics.
If the stains on the fabric are classified according to their solubility, they can be roughly divided into two categories: fat soluble and water soluble. Most of the stains, especially those difficult to clean, such as blood, milk stains, oil stains, etc., are fat soluble substances. They are not easy to combine with water, and the cleaning ability of conventional washing process is poor, while it is easier to use fat soluble organic solvents to clean such substances, which is the same reason that working people thought of using kerosene to clean oil stains on clothes in early years.
Using fat soluble organic solvents can easily remove oil stains on clothes
Another advantage of using organic solvents is that they have less fiber damage to some fabrics than water. In addition, organic solvents can kill more microorganisms during the cleaning process.
Is tetrachloroethylene a dry cleaning agent that should not be used?
Because of these characteristics of dry cleaning, when choosing an organic solvent (or a combination of several chemical substances) as a dry cleaning agent, the key indicators are the solubility of fat soluble substances, the degree of damage of dry cleaning agent to fiber and color, and its bactericidal ability. In addition, from the practical point of view, it also depends on whether the dry cleaning agent can be removed from the clothes as simply as possible after cleaning, as well as the cost, toxicity and other factors of the dry cleaning agent.
Compared with petroleum hydrocarbon solvents such as kerosene and gasoline, tetrachloroethylene is indeed more toxic other It has obvious advantages in all aspects, so until now, it is still the dry cleaner used by most dry cleaners, and it is also the permitted dry cleaner.
Although it is permitted to use, for consumers, toxicity is just a concern.
How to make tetrachloroethylene become security
In fact, consumers don't need to worry security Sexual. adopt The dose of tetrachloroethylene exposed to dry cleaned clothes is extremely limited, which is far from enough to cause allergy, anesthesia and other symptoms, and will not cause hepatotoxicity, cancer, etc other Toxicity that requires greater dose and longer exposure. This can be seen from the steps of dry cleaning.
Do you know how many steps are needed for dry cleaning?
Similar to daily washing, dry cleaning of clothes can be divided into three steps: soaking clothes in solvent, adopt Rolling makes the stain fully contact with the solvent and be taken away from the fabric (in water washing, because most stains are insoluble in water, this process needs the help of detergent); Centrifuge to remove dry cleaning agent (there is no need to add detergent, so there is no rinsing step in water washing); Heat to further remove the dry cleaning agent on the fabric (organic solvent is more volatile than water, which is easy to remove from the fabric, but the drying process will still raise the temperature to about 80 ℃, and stay for 15 minutes to ensure that the dry cleaning agent is removed as clean as possible).
If consumers are still uneasy about the clothes that have gone through this harsh drying process, you can also hang the clothes just taken back from the dry cleaner for a day or two before putting them in the cupboard.
The amount of perchloroethylene residue on the dry cleaned fabric is very low even if it is tested by the current sophisticated instrumental analysis method. If it is left for a few days, even if it is not ventilated, the amount of perchloroethylene residue on the fabric can hardly be detected. Considering that the clothes sent for dry cleaning are usually not worn close to the body, the possibility of contact is even less. Consumers don't need to worry about their own security 。
What really needs to be worried about is the environment of the dry cleaner and the operators there.
"Green" dry cleaning
In an industry, the best way to protect employees and the environment is to find cheap and non-toxic raw materials.
The employees in the dry cleaning shop are closer to the hazards of dry cleaning agents
More than 60 years ago, tetrachloroethylene determined its position in the dry cleaning industry, which has not been shaken, but it has been trying to find more security The goal is still to replace the solvent. At present, the ideal alternative is liquid carbon dioxide, which is non-toxic and easy to separate from fabric. Although its cleaning power is slightly inferior to that of tetrachloroethylene, it is really promising. However, at the current technical level, the operation cost is still too high to maintain carbon dioxide in liquid state. So the dry cleaning agent is still waiting for more advanced technology to detoxify and reduce its price.
If cleaner alternative materials cannot be found, we can also take second place and limit the leakage and discharge of toxic materials by more means. For example, using a fully enclosed dry cleaning machine can recover tetrachloroethylene evaporated in the drying process, which not only saves costs, but also protects employees and the environment. In addition, used tetrachloroethylene can adopt Distillation and purification realize reuse, which reduces consumption and pollution. In addition, employees need to take protective measures.
In many cases, technology is the main means to solve problems, but before it appears, good management is needed to protect security.
Conclusion: At present, the dry cleaning industry cannot realize the non-toxic dry cleaning agent, but the trace residues on clothes do not pose a threat to the health of consumers.
Laundry tips:
1. Not all clothes are suitable for dry cleaning, please follow the washing instructions on the clothes.
2. After the dry cleaned clothes are taken back, the residual amount of dry cleaning agent can be too low to be detected after being placed in a ventilated place for 2-3 days.
3. Polyester fabric has a slightly stronger ability to retain tetrachloroethylene. It is recommended to wash it with water. If it is dry cleaned, it needs to be dried more.
Changzhou Xuemo Washing and Dyeing Co., Ltd. provides comprehensive after-sales services to the majority of dry cleaning entrepreneurs, including shop opening guidance, equipment commissioning and installation, learning and training, equipment maintenance and other one-stop services, so that entrepreneurs can open stores smoothly.
