Wool is a natural protein fiber, which is mainly composed of proteins called keratin. Wool fiber is composed of three parts: the outer scale layer, the cortical layer that makes up the wool body, and the medulla layer in the center of the hair stem. The medulla layer exists only in coarse wool, but not in fine wool.
Characteristics of Wool Fiber:
① Felting Property.
Under hot and humid conditions, wool fibers and their fabrics are interspersed with each other and interwoven with each other under the action of mechanical force, which is called the felting property of wool.
It is better, the public moisture regain is 1517%, the limit moisture absorption is 40%, and the moisture absorption is better than cotton.
Under hot and humid conditions, wool expands and loses its elasticity. Under the action of external force, it is pressed into various shapes and cooled rapidly, and the external force is released. The pressed shape can remain unchanged for a long time. This property is called plasticity. (cooking and steaming).
It has the best elastic resilience among the natural fibers.
⑤ Heat Resistance.
Dry heat treatment at 60 ℃ had no great effect on wool, but the temperature increased and deteriorated gradually. After drying at 100 ℃ for 1 hour, the color turned yellow, the strength decreased, dehydration occurred at 110 ℃, dark brown at 130 ℃, bad smell at 150 ℃, and coking at 200 ~ 250 ℃. When wool is treated at high temperature for a short time, its properties do not change.
⑥Acidity and Basicity.
Acid-resistant, not alkali-resistant. The resistance of wool to acid is stronger than that of cotton, and the dilute solution of weak or strong acid has no significant destructive effect on keratin at low or room temperature, while the resistance of wool to alkali is much lower than that of cellulose, and its strength decreases obviously under alkaline condition. The color is yellowing, the luster is dim, and the feel is rough and hard.