The reason for this is the following：
First, wash away the dirt:
In a series of processes, such as production, processing, transportation and sales, new clothes will inevitably be contaminated with all kinds of dirty things, such as oil stains on equipment, dust contaminated during transportation and handling, and hand contact of salespeople or consumers during sales, which will cause certain pollution to the clothes surface. It is best to remove foreign body pollution when washing.
Second, remove chemicals.
1. formaldehyde: there are various chemical raw materials in the process of clothing manufacturing and processing. Formaldehyde is one of them. Formaldehyde is a chemical raw material. Adding formaldehyde can play the role of color fixation and wrinkle prevention. However, if the formaldehyde content is too heavy, the "free" formaldehyde will cause skin allergies, itching, dermatitis and other symptoms after being absorbed by the human body. Washing can effectively remove the substance.
2.NPE: It is widely used in garment printing, dyeing and cleaning. After long-term contact with human skin, it will affect endocrine and reproductive functions, which has a great impact. But NPE can be dissolved in water, and washing new clothes in water can remove most harmful substances.
2, pigment: there are many dark clothes, there will be slight floating color, poor quality or even severe dehydration, if you wear them without cleaning, you will not find that the clothes will fade, and toxic and harmful substances in the printing and dyeing process will enter the human body through the skin, causing diseases.
Extended data:
Pants washing method:
1, dark jeans can be soaked in white vinegar and water (the ratio is 1: 20) or salt water for more than 30 minutes, and the color can be fixed.
2, dark series and light series should be washed separately, mixed together will cause color mutual dyeing.
3. Wash with blue granular washing powder without enzyme, because the washing powder containing enzyme has bleaching effect, which affects the color of jeans. Remember not to use bleach.
4. Avoid direct sunlight. After washing pants, dry them in a ventilated and dry place to avoid direct sunlight, which will cause serious oxidation and fading.
5, drying in a ventilated place, no ventilation will make pants not easy to dry and will produce odor.
6. When washing pants, generally wash the front and dry the back, which can not only be clean, but also avoid the damage of sunlight to pants.
References:
Baidu encyclopedia-pants