□ After all clothing fibers enter a relatively humid environment from a dry environment, the air or human body absorbs the evaporated moisture, and heat energy is generated during the moisture absorption process. The more moisture absorption, the more heat dissipation. After testing, the heating effect of self-heating underwear is improved to some extent compared with that of ordinary cotton underwear, but the difference in temperature rise is not high.
□ When purchasing "black technology" warm clothing, consumers should carefully check the product label, and give priority to three products with complete standards, detailed content, verified by the manufacturer and qualified quality inspection.
Recently, with the sharp drop in temperature, the sales of thermal clothing have reached a peak, and thermal clothing products with "self heating", "far infrared" and "graphene" as the selling points are hot in the market. Compared with natural fiber, is thermal insulation clothing with "black technology" reliable?
It is reported that the National Textile Product Quality Supervision and Inspection Center has specially tested three different brands of hygroscopic and thermal underwear purchased from physical stores and online stores. After the inspector has completely dried the hygroscopic and thermal underwear, put it into the test box with a temperature of 20 ℃ and a humidity of 90% for 30 minutes. The results show that the three samples generate heat after moisture absorption, and the temperature rise is basically the same. The maximum temperature rises at about 7 ℃, and the average temperature rises at about 2.7 ℃ within 30 minutes.
Under the same conditions, the inspector tested the traditional cotton underwear. Results The maximum temperature of cotton underwear increased by 5.9 ℃, and the average temperature within 30 minutes increased by 2.0 ℃. It can be seen that the heating effect of self-heating underwear is improved to some extent than that of ordinary cotton underwear, but the difference in temperature rise is not high.
Wang Baojun, director of the National Textile Product Quality Supervision and Inspection Center, said that after all clothing fibers enter a relatively humid environment from a dry environment, the air or human body absorbs the evaporated moisture, and heat energy is generated in the process of moisture absorption. The more moisture absorption, the more heat dissipation. Some self-heating clothes add other substances to the ordinary fiber to increase the hydrophilic group in the fiber, increase the moisture absorption and improve the heating effect.
The laboratory of the National Textile Product Quality Supervision and Testing Center also tested the heating effect of far-infrared thermal underwear. The results showed that the clothes did emit far infrared rays, and the temperature also increased, with an average temperature of 1.6 ℃, but the temperature was not significantly higher than other hygroscopic and thermal underwear.
An insider pointed out that the far-infrared thermal underwear made of fiber materials, ceramic powder, graphene and other materials can make the clothes radiate a certain amount of far-infrared light, resonate with the water molecules in human cells, produce thermal effects, promote subcutaneous blood circulation, and thus warm the human body. However, because the clothing fiber is very fine, the additive should not be too much, otherwise the elasticity and strength of the fiber will be affected.
Liu Li, a professor at Beijing Institute of Fashion, believes that in recent years, there are many kinds of thermal insulation clothing products with "self heating", "far infrared" and "graphene" as the selling points, but the new products lack the necessary industry standards. In the long run, "black technology" thermal clothing needs to make continuous breakthroughs in product innovation, form unified norms in standard formulation, and gain more trust in brand construction in order to better meet consumer demand.
How should consumers choose colorful "black technology" warm clothing.
The relevant technical director of Tristar (Beijing) Textile Testing Co., Ltd., which specializes in textile testing and certification, told the reporter that the traditional thermal underwear chemical fiber fabrics are made of polyester, acrylic, viscose, nylon and other fibers, which often appear in the fabric composition in different proportions. The biggest characteristic of acrylic acid is that it has a natural shrinkage and soft structure like wool. The fabric made of acrylic acid stores a lot of air, prevents heat loss, fully insulates but does not absorb moisture, and the adhesive is breathable but not fully insulates. The polyester fiber profiled section has the moisture conductivity function and improves the fabric strength. Nylon can effectively improve the comfort of underwear. In production, manufacturers generally design fabrics, scientifically blend and learn from each other to better meet the functional requirements of thermal insulation clothing products.
"According to the needs of the scene, it is best to be the most suitable one," suggested Lu Zhenxing, director of the Technology Research and Development Center of Lipai Warp Knitting Technology Co., Ltd., in order to keep clothes warm as much as possible in the cold winter outdoors, it is best to use the "sandwich" dressing method, that is, wind prevention, heat preservation, and moisture absorption can close the body heat. The outermost layer is a windproof layer, usually made of hard and high-density materials, to prevent the cold wind from directly invading the body surface and prevent the body from taking away heat. The middle layer is the thermal insulation layer, which plays the role of heat storage through materials with high thermal insulation such as sweaters, down jackets or down jackets. The thermal insulation underwear focuses on ventilation and moisture transmission, and the application of thermal insulation concept materials is also considered. The core strength of clothing to play its thermal insulation function is the middle thermal insulation layer and the outer windproof layer.
Experts suggested that consumers should not follow blindly. When choosing warm clothing with "self heating", "far infrared", "graphene" and other selling points, they should carefully check the product label, and give priority to three products with complete standards, detailed content, factory verification and qualified quality inspection.