The internal quality indicators of cotton fiber mainly include fiber length, fiber fineness, fiber strength and fiber maturity.
The fiber length refers to the distance between the two ends of the straightened fiber. There are different methods for measuring fiber length. The length measured by the hand-drawn ruler is called the hand-drawn length; the length measured by the combing method is called the combing length; the length measured by the cotton fiber end-electricity length meter is called the end-electricity length; the large-capacity fiber analyzer is used The measured length is called the span length, and 2.5% span length is commonly used, referred to as 2.5% fiber span length. Under normal circumstances, the carding length> the length of the hand pull, the length of the power-up> 2.5% of the fiber span. The length of cotton fiber is closely related to the yarn strength. Spinning with longer fibers will increase the cohesion length between the fibers. When the spinning yarn is subjected to external forces, the fibers will not slip easily and the yarn strength will be higher.
The fineness of cotton fiber refers to the thickness of the fiber, and its direct meaning is the diameter of the fiber cell. Because the diameter of cotton fiber is difficult to directly measure, and the main measure of cotton yarn thickness is the weight fineness, that is, the length per unit weight, so the weight fineness is often used to describe the fiber thickness. Nowadays, the airflow meter is commonly used to measure the fineness of the fiber, that is, the specific surface area of the fiber is quickly determined by the principle of airflow, and the fineness of the fiber is estimated from this, expressed by the micronaire value. The fiber fineness is closely related to the yarn strength. Because cotton yarn is made of multiple fibers, the strength of the spinning yarn is determined by the strength of the fiber itself, as well as the number of fibers per unit spinning yarn fineness. , The degree of relative slippage between fibers is related to the evenness of evenness. For spinning high-count yarns, only raw cotton with longer fibers and better fineness can be used.
The cotton fiber strength refers to the strength of the cotton fiber against tensile fracture. When other indicators are basically the same, fiber strength is positively correlated with yarn and cloth quality. In the case of high speed of modern spinning equipment, the fiber strength is high, which plays an important role in reducing the rate of end breakage in spinning and improving production efficiency.
The maturity of cotton fiber is an important indicator reflecting the degree of thickening of the fiber cell wall. In the case of similar fiber cell diameters, the thicker the cell wall, the higher the maturity. The fineness, micronaire value, strength, and color characteristics of cotton fibers are closely related to maturity.
High-quality raw cotton fiber requires that the main physical performance indicators must be coordinated, that is, the length, strength, fineness and uniformity of the fiber must be reasonably matched with each other. Good individual indicators cannot represent good overall quality.