In the winter warm clothing market, many close-fitting underwear are marked with the function of "sentimental heating", claiming that the clothing itself can heat up and heat the human body. So is this " self-heating " function real?
From the perspective of the law of conservation of energy, heat is of course impossible to produce out of thin air, so there is no "spontaneous heating" clothing that can "create something out of nothing". So how do these magical materials produce heat? What should we pay attention to when we wear and wash these clothes?
magic heating fiber
All kinds of self-heating fibers are actually heated with the help of external forces. For example, light energy heating fibers rely on absorbing sunlight and reflect the heat radiation of the human body; electrical heating fibers heat when they are energized; phase change fibers use the phase change of substances to release or absorb latent heat to adjust the temperature. The most commonly used heating mechanism in daily clothing is "hygroscopic and heat".
hygroscopic heating fibers mainly absorb water vapor, that is, sweat, and form hydrogen bonds to emit heat. Common textile fibers have the ability to absorb moisture and heat, but the heating capacity of different varieties varies. Specialized self-heating fibers have more hydrophilic group in the chemical composition, and the fibers have better hygroscopic properties and more heat emitted after hygroscopic absorption.
In order to improve the hygroscopic properties of the fiber, not only can the fiber be added to the hydrophilic group for hydrophilic treatment, but also can change the surface morphology and structure of the fiber to facilitate the adsorption of water molecules on the surface of the fiber.
Hygroscopic heating fibers exothermic the heat by absorbing moisture, but after the fiber "sucks" moisture, its exothermic reaction will slow down. The moisture-absorbing fibers will also discharge moisture, and this process will absorb heat. If the moisture cannot be dehumidified in time, the moisture-absorbing fibers will cause discomfort to the wearer.
In order to improve this discomfort, many fabrics use moisture absorption and heating fibers and other types of fibers to achieve a balance between moisture absorption, heat removal and dryness.
Self-heating clothing has "standard"
Currently, there is no mandatory standard for hygroscopic heating underwear in my country. You can refer to the industry standard FZ/T 73036-2010 "Hyroscopic heating knitted underwear" to evaluate hygroscopic heating underwear. This standard proposes two indicators on hygroscopic heating performance. One is that the maximum temperature rise value is greater than or equal to 4.0℃, and the other is that the average temperature rise value is greater than or equal to 3.0℃ within 30 minutes.
In addition, underwear that meets the standards will be clearly marked in the column of the product tag that meets the FZ/T73036-2010 "Hydrink Knitted Underwear" standards, which can be used for reference when purchasing.
For infants and young children with delicate skin, it is not recommended to wear moisture-absorbing and heating underwear, because moisture-absorbing and heating underwear reciprocates in the hygroscopic-heat-exhausting cycle, which can easily cause skin discomfort in infants and young children.
Electric heating clothing generally uses external power supply. As long as the electricity is constantly powered, it can last for long-term heating. It is very suitable for people who work outdoors for a long time in severe cold outdoors. Commercially available electric heating clothing is generally powered by a small power bank, with a small voltage and relatively safer. Consumers mainly pay attention to the fact that the electric heating fibers should not bend or fold, resulting in local overheating and scalding.
self-heating clothing, how to clean it?
hygroscopic heating fibers will not be affected after daily cleaning, so they can be cleaned normally. However, since the fabrics of hygroscopic heating underwear are often made of a variety of fibers, including hygroscopic heating fibers, some fabrics also adopt special weaving processes. It is recommended to wash gently in warm water during cleaning, avoid using high-temperature water and hard rubbing, and avoid exposure to the sun.
It is generally not recommended to use water washing for electric heating clothing. Water washing will cause damage to electric heating fibers or heating units, reduce the heating effect or bring safety hazards.
Editor: Wen Qianting
Data: People's Daily
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