While warmth is closely related to fabric thickness, outdoor sports don't allow for overly heavy clothing. Therefore, clothing must be both warm and lightweight to meet the specific requirements of outdoor sportswear. The most common method is to add special ceramic powders, especially nano-sized micro-ceramic powders, containing chromium oxide, magnesium oxide, and zirconium oxide, to the spinning solution of synthetic fibers such as polyester. These powders can absorb visible light such as sunlight and convert it into heat energy, and can also reflect far-infrared rays emitted by the human body, thus possessing excellent heat insulation and heat retention properties.
Alternatively, far-infrared ceramic powder, binders, and cross-linking agents can be formulated into a finishing agent, which is then used to coat the woven fabric. After drying and baking, the nano-ceramic powder adheres to the fabric surface and between the yarns. This finishing agent emits far-infrared rays with wavelengths of 8-14 μm and also has health benefits such as antibacterial, deodorizing, and blood circulation-promoting functions.
Furthermore, based on biomimicry principles and referencing the structure of polar bear fur, polyester fibers are made porous and hollow inside, containing a large amount of non-circulating air, while the outside is made into a spiral curl to maintain fluffiness. Both methods provide good insulation while ensuring a lightweight texture. Of course, making clothes or even fabrics into double or triple layers to increase the number of non-circulating air layers is also one of the most traditional methods of insulation.
