The raw material of heating underwear is a special fiber material imported from Japan around 2000, which actively heats up by absorbing the moisture emitted by the human body. This fiber material was first used for mountaineers, and later extended to the general consumption field, mainly used for making underwear. The materials used in the heating underwear produced by domestic manufacturers are all imported from Japan.
Because this kind of fiber material is expensive, general heating underwear is made of a small amount of heating fiber mixed with other fibers. Yang Shibin, chairman of the China Knitting Industry Association, added that, therefore, it is impossible for real heating underwear to rise that high, and generally it can actively raise the temperature by 2℃ to 4℃.
The concept of "self-heating" declared by extended data vendors does not conform to the law of conservation of energy. Fiber heating must have energy. At present, the "self-heating underwear" on the market mostly uses the principle of fiber moisture absorption and heat generation. That is to say, when the fiber absorbs water, the hydrophilic groups in the fiber molecules combine with water molecules, and the kinetic energy of water molecules decreases, which is converted into heat energy and released.
The moisture absorption and heating properties are closely related to the moisture regain of fibers. Fiber has high moisture regain, good moisture absorption and heating performance and low moisture regain. For example, wool and modal fibers have good moisture absorption and heating effects, while ordinary acrylic fibers and polyester fibers have poor moisture absorption and heating effects. So the principle of this kind of heating underwear is actually to absorb the moisture of the wearer to achieve the function of heating.
Not suitable for dry north. In winter, people sweat less, so it is difficult for fibers to absorb water and heat. There are still many people who report that wearing hot underwear is easy to itch, which may be because the original dry skin moisture is absorbed by underwear.
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