Chemical fiber felt in the processing process is often subject to stretching, curling, twisting and other external forces, so that the fiber to change the original form. As the wool has good elasticity, it tries to return to its original form, so that various stresses are generated inside the fiber. This internal stress needs to gradually decay for a long period of time until it is eliminated. It often gives the wool Causing difficulties, which is wool products in the processing and use of the size and shape of one of the factors of instability. Wool plasticity refers to the wool in the hot and humid conditions, can make its internal stress quickly decay, and by external force to change the existing form, and then by cooling or drying to maintain the shape of the nature.
The main rest of the wool fiber is the cortical layer composed of cortical cells. Sheep felted cortical cells contain high sulfur and low sulfur two kinds of protein, the former is the main component of the matrix, the molecular chain was amorphous curl; the latter molecular chain with a spiral structure, cortical cells in the basic fibrils (protofibril) The The basic fibrils are then composed of microfibrils, and the fibrils are further composed of fibrils. All kinds of fibrils are embedded in the tombstone, the fibrils and the quality can be connected by disulfide bonds. Some studies have shown that: 0.5 cortical cells in the original fiber diameter of about 0.25m, the diameter of microfibrils is 7.5nm (75A), the basic fibril diameter of about 2nm.