"Black Technology" Underwear Is Really Warm Or IQ Tax

As the temperature drops, the sales of warm clothing enter the peak period, and mask clothing, muscle bottom clothing, fast heating clothing... dazzle people. Self heating, far-infrared and graphene sound full of "technology and ferocity". Some businesses claim that "black technology" has been used in thermal underwear, so it will not be cold to wear it at minus 40 ℃. Are these "black technologies" really warm or an IQ tax?

"Self heating" underwear cannot "generate heat out of nothing"

Human body is its main heat source

In the winter warm clothing market, many intimate underwear are marked with "self heating" function, claiming that clothing can heat itself to heat the human body.

　　 in fact, According to the law of conservation of energy, heat cannot be generated out of thin air. All "self heating" is actually heating by external force. At present, most of the "self heating underwear" on the market uses the principle of fiber moisture absorption and heat generation, that is Absorbs the moisture of the wearer to achieve the function of heating When the fiber absorbs water, the hydrophilic group in the fiber molecule combines with the water molecule, and the kinetic energy of the water molecule decreases, which is converted into heat energy and released.

　　 Wang Xudong, President of Beijing Graphene Technology Research Institute and Doctor of Materials Science, said, "Self heating" has an exaggerated component. All heat needs a heat source. The human body is the main heat source of thermal underwear. Unless the clothing itself has other electric heating conversion or electric heating driving ability, it is difficult to achieve "self heating". The thermal underwear is to maintain and use the heat of the human body to a greater extent, so that the human body can be more comfortable and adapt to outdoor work for a longer time.

    Uncover the insulation principle of "graphene" and "far-infrared" materials

　　 In the past two years, some thermal underwear claimed to contain scientific and technological materials such as "far-infrared" and "graphene". Some netizens said that each gram of graphene products is worth about 1000 yuan. If graphene is used to make a thermal underwear, the cost is conservatively estimated to be tens of thousands of yuan. Therefore, most of the autumn clothes and trousers that cost several hundred yuan each are not really graphene. Is that true?

　　 Wang Xudong explained that what netizens said was pure graphene products, Graphene added in chemical spinning is very limited, generally 1/1000 to 5/1000 In addition, under the same quality conditions, the price of graphene has dropped to a level that ordinary people can afford.

　　 Experts emphasized that, Due to the low addition content, the cost of graphene thermal underwear often depends not only on the graphene itself, but also on the types of clothing raw materials and fibers, as well as the manufacturing process integrated with graphene.

Graphene is the basic structural unit of carbon materials, and it is a kind of nano material with high strength, high conductivity and excellent thermal conductivity. Graphene fiber can be used to make clothes with antibacterial, deodorant, UV protection and other functions. The mechanism of graphene emitting far-infrared light to the human body after absorbing human heat, It is the working principle of graphene thermal underwear.

　　 In addition, the experts introduced that far infrared textiles are an efficient thermal insulation material. The heating principle is to absorb heat first and then release heat. It absorbs two kinds of energy:

　　· One is the energy in the environment, such as visible light, infrared light, far-infrared light, etc. in the sunlight;

　　· The other is the energy emitted by the human body itself. After absorbing the energy, the far-infrared fiber will convert it into far-infrared and then radiate it back to the human body, so as to provide heat for the human body.

Expert: pay attention to identify thermal underwear

Exaggerate publicity and limit washing times

Experts remind that no matter what material, it can heat up through moisture absorption, but the degree is different. When selecting and purchasing hygroscopic heating underwear, in addition to identifying some exaggerated publicity, When purchasing from formal channels, pay attention to the limited washing times of thermal underwear 。

　　 When selecting and purchasing hygroscopic heating underwear, you can also check the tag information, The thermal underwear that meets the standard will be clearly marked in the column of executive standard: it conforms to the standard of FZ/T73036-2010 Hygroscopic Heating Knitted Underwear. This standard proposes two indicators on hygroscopicity and heating performance:

　　· The maximum temperature rise is greater than or equal to 4.0 ℃;

　　· The average temperature rise within 30 minutes is greater than or equal to 3.0 ℃.

　　 When the humidity is saturated, the hygroscopic heating fabric cannot provide more heat.

　　 Wang Xudong said that theoretically, all products have a life span, but since the hygroscopic heating standard is marked, the washing times of products must be limited within the standard. Has

　　 Is it true that plush clothes and trousers are glued and poisonous?

　　 In the past two years, plush clothes and trousers have also been sought after by people, but some netizens said that the composite plush thermal underwear fabric is adhesive, which not only has high formaldehyde content, but also is toxic. What's the matter?

　　 In this regard, experts said that "compounding" is to combine two different fabrics together, which is a common process. "Composite flocking" usually refers to the combination of a layer of ordinary fabric and a layer of brushed polyester fiber (i.e. "polyester") to form a fabric similar to coral wool, fleece and cashmere, The key to "composite flocking" is the glue used . The fabric shall be compounded to ensure a certain softness, Urea formaldehyde resin and phenolic resin glue have high hardness and are usually not used 。

　　 At present, hot melt adhesive and oil glue are commonly used for bonding of composite fabrics on the market. Polyurethane hot melt adhesive is the most commonly used hot melt adhesive in the clothing field. It has the advantages of high bonding strength, good flexibility, heat resistance and water resistance, and does not release formaldehyde, meeting the safety standards. In order to reduce costs, some manufacturers will choose to use oil glue, which is dissolved with organic solvents. Although it does not contain formaldehyde, the residual volatile organic solvent may cause potential harm to human health. Consumers can identify it by smell. If clothing has a pungent smell, it is recommended not to buy or return it directly.  

(Source: CCTV News WeChat Official Account)