This year, the concept of aerogel is very popular. Air gel cold clothing appeared in the market, and businesses claimed that air gel is an aerospace material, which can achieve better warmth retention than down, and is more lightweight and breathable. So, can aerogel really replace down and become a new generation of winter artifact?
Aerogel is a kind of three-dimensional network structure material that envelops a large number of closed micropores. It is the lightest and smallest density solid in the world. At present, there is no uniform definition of it in the industry. Strictly speaking, it is not a material, but a kind of material morphology structure. Many materials can be called aerogels as long as they can maintain their basic shape, have high porosity (generally more than 80%) and low density. The aerogel contains a large number of nanoscale micropores with high hollowness, so its thermal conductivity is low and its thermal insulation efficiency is good.
The aerogel products on the market include aerogel gel cold clothing, aerogel gel gold standard P cotton padded clothes, aerogel gel double cold clothing, aerogel cotton trousers, aerogel gel thermal underwear, aerogel gel thermal quilt and other products. A considerable part of the washing marks of these products are made of ordinary fabrics, which has nothing to do with aerogel. The fillers related to aerogel can be divided into three categories: first, 100% polyester fiber (polyester); Secondly, polyester fibers are blended with viscose fibers (viscose fibers), polyacrylonitrile fibers (acrylic fibers), polyurethane elastic fibers (spandex), wool and other fabrics; Thirdly, polyester fibers and polyimide fibers are blended. Some businesses will also specifically mark: "polyester fiber uses aerogel moisture prevention technology" or "aerogel gel detects that it is polyester fiber". In other words, the aerogel material claimed by the business is actually polyester fiber.
Can polyester fiber be made into aerogel structure?
The mechanical properties of aerogel fiber are generally weak, and the high porosity can not support the spinning process of polyester fiber at all, so it is easy to break. Therefore, polyester fiber cannot be made into a real aerogel structure. A considerable part of the above businesses use aerogel coating technology, that is, a layer of silica aerogel is coated inside the clothing fabric, but generally the coating is very thin, the material is very brittle, and slag will fall with wear and washing, and the heat preservation effect will become worse and worse. Others will choose to use PU coating to stick the aerogel powder to the fabric, but the adhesive will affect the porosity of the aerogel, and then affect the heat insulation effect of the clothes. Therefore, the thermal insulation effect of the aerogel clothing made by coating technology will gradually decline with the increase of use times.
In addition, there is a star brand of air gel cold clothing, which is said to be made of polyester fiber and polyimide fiber, which is a high-performance fiber used in space suits and protective clothing to play a role in heat insulation. The washing label indicates that the filling material is 1: 88.5% polyester fiber and 11.5% polyimide fiber. Filler 2: Non fibrous material (silica aerogel characteristics).
However, space suits and protective clothing belong to a special personal equipment system. Polyimide aerogel is used as interlayer to protect human body from external high-temperature environment. In the cosmic environment, the local temperature may reach 1000 ℃, at which time the down will be burnt, while the aerogel will not. In this case, aerogel has advantages.
Bugaiqi gel is more suitable for heat insulation in extreme environments, especially high temperature environments, rather than being made into cold proof clothing for cold protection. It is not necessary for daily wear. In addition, as a thermal insulation material, aerogel is only a part of the spacesuit system. In the cosmic environment, other materials and equipment need to be equipped to achieve the moisture and heat balance between the human body and the external environment. The spacesuit is a system completely different from daily clothing.
There is an aerogel winter jacket that claims to be made of polyimide fiber. At about 0 ℃, it is really warm, but it will feel a little stuffy if worn for a long time. Some consumer reviews suggest that wearing it at -20 ℃ still feels cold, and its insulation effect is not as good as down jackets. Due to the fact that the main filling material of this anti cold suit is still polyester fiber, its characteristics are still similar to traditional synthetic anti cold suits.
It can be seen that although there are many aerogel products on the market, many of them play a marginal role in structure, performance and other aspects, and there is a serious phenomenon of speculation. Consumers should pay attention to the fabric labels when shopping, and make rational choices as needed.