(1)Fineness: The cross section of wool fiber is approximately circular, and its diameter is generally used to indicate its thickness. It is an important indicator to determine the quality and use value of wool
The fineness of wool varies greatly, with a minimum diameter of 7um and a maximum thickness of 240um. The method for expressing the fineness of wool is as follows:
① Quality Count: It is the most widely used fineness representation method in wool spinning production in various countries around the world. As early as the 18th century, according to the current level of spinning equipment and technology, as well as the quality requirements for wool yarn, the highest count of wool of various fineness actually spun (English count) is called quality count. This represents the quality of wool. With the development of science and technology, the improvement of textile methods, With the continuous improvement of textile quality requirements and the progress of fiber performance research, the quality count of wool has gradually lost its original significance. Now, the quality count of wool only represents the fineness of wool within a certain range of diameter.
② Average diameter: The fineness of wool is often expressed in terms of diameter. Due to the uneven thickness of wool, the number of pieces measured is generally large. For homogeneous wool, 300 pieces are measured, and for heterogeneous wool, 400 pieces are measured. The calculation is carried out in groups.
③ Metric number of branches: Nm=L/g
(2) Length: Due to the existence of natural curl, the length of wool fibers can be divided into natural length and straight length. Under natural curl, the linear distance between the two ends of a fiber bundle is called natural length. Generally, natural length is used to represent the length of the wool clump. The length of wool fibers after elimination of bending is called straight length. In wool mill production, the straight length is often used to evaluate the quality of wool
The length of wool is second only to fineness in terms of technology. It not only affects the quality of wool fabrics, but more importantly, it is the basis for determining the spinning system and selecting process parameters.
(3) Curl: Wool has a natural periodic curl along the length direction, also known as hair waves,
The degree of curl expressed in terms of curl per centimeter is called curl. The shape of curl can be divided into the following types:
Weak curl (coarse wool) Normal curl (fine wool) Strong curl (fine wool, abdominal hair)
In fine varieties of wool, the positive and partial cortical layers are distributed on both sides of the hair shaft, with the positive cortical layer being the outer side and the partial cortical layer being the inner side
Coarse and long wool has a positive cortical layer gathered in the center of the hair shaft, and a partial cortical layer circularly distributed around it. This type of hair has no curls, such as Linken hair and mohair
"Some hairs are mixed and distributed in the positive and lateral cortical layers. The yarn formation process of fibers with large curls is good for mutual accommodation, low hair loss, good cashmere shrinkage, and smooth and tight."
Woolen fabrics require a full surface, good handle, and high strength. Therefore, woolen yarns are required to be soft and strong. It is best to choose strong crimp fibers from the raw materials
Worsted wool fabrics require clear lines, soft luster, and regular shapes, so wool yarns need to be smooth, uniform, and tight. Therefore, it is best to choose wool fibers that are normally curled and have a dense degree of curl
Due to the coarseness of weakly crimped fibers, worsted yarns are generally not used
The curl and shape of wool have a close relationship with the cashmere shrinkage of wool products. Generally, the denser the curl, the greater the elongation, and the better the cashmere shrinkage.
(4) Net wool percentage of raw wool: When determining the moisture regain, the percentage of pure wool to raw wool obtained by washing the wool to remove oil, sweat, and impurities
