This starts with the principle of keeping warm
The clothes we wear do not generate heat, they rely on preventing the loss of heat generated by the human body to keep warm.
Among gases, solids and liquids, gases have the lowest thermal conductivity, and air has a much lower thermal conductivity than the fiber material itself. If a fiber can hold a large amount of still air, it can provide a good warmth-keeping effect. Down is just such an animal fiber.
The main sources of down materials are geese and ducks. There are two types of down on the bodies of birds: long feathers and short down. Long feathers are mainly used for flying and sunshade, while short down has the function of keeping warm. Short down is used in down products because it is soft, light and has good thermal insulation performance.
The thermal insulation performance of down mainly depends on two factors: the density of the down and the filling amount of the down filling. The density of the down refers to the spacing between the down. The greater the density, the smaller the air layer between the down, and the less likely the heat is to dissipate, thus providing better thermal insulation. The filling amount of the down filling refers to the degree of filling of the down filling in the clothing. The greater the filling amount, the better the thermal insulation performance of the clothing.
1. The structure of down
Down is a mixture of "feather" and "down cluster ".
"Feather" has feather shafts that bend inward, with soft barbs on both sides and dense barbs at the root. The feather affect the elasticity of down.
"Down balls"is a three-dimensional spherical structures, radiating two or more filaments from a down core to the surrounding areas, without feather rods. Down balls play a key role in the performance of down.
2. Features of down
Warmth:The three-dimensional spherical structure can hold more still air, which is a poor conductor of heat, so down is very warm. In addition, down fibers are made up of thousands of tiny scales stacked on top of each other. Each scale is hollow and each down fiber has many nodes, which are also full of stagnant air.
Not easy to stick:Linear fibers( like Cotton, Silk, Chemical fiber)will stick after a period of use, and the warmth retention, fluffiness and comfort will be reduced. Down is not easy to stick because of its three-dimensional spherical structure, and its performance is more sustainable. Three-dimensional spherical shape allows the down to contain a lot of air, making it soft and gentle.
