Classification And Characteristics Of Cotton Fiber

China's cotton output has entered the forefront of the world. Cotton planting in China is almost all over the country. Among them, the the Yellow River River Basin and the Yangtze River Basin are the main areas, plus the five major cotton regions in the northwest inland, Liaohe River Basin and Southern China. Cotton fiber It is the main raw material of China's textile industry. It occupies a very important position in textile fibers. China is one of the major cotton producing countries in the world. Most of the cotton plants are annual plants. It is developed from the epidermal cells that are bred on the seeds of cotton. Cotton fiber can be divided into three stages: elongation stage, thickening stage and turning stage. There are many kinds of cotton, which are classified according to the following two methods.

　 Classification according to cotton varieties

(1) fine cotton: fine cotton is also known as upland cotton. The fiber density and length are medium, the average length is 25 ~ 35mm, the linear density is 2.12 ~ 1.56 dtex (4700~6400 public branches), and the strength is about 4.5cN. Most of the cotton grown in China belong to this category.

(2) long staple cotton: long staple cotton, also known as island cotton. The fiber is thin and long, with a normal length of 33mm and a linear density of 1.54 to 1.18dtex (6500~8500 common branches). The strength is above 4.0cN. It is of high quality and is mainly used for the preparation of superior cotton yarn which is smaller than 10Tex. At present, there are few plants in China. Besides Xinjiang's long staple cotton, the main imports are Egyptian cotton, Sultan cotton and so on. In addition, coarse staple cotton with short fiber has been phased out.

　 Classification of cotton according to primary processing

Cotton seeds from cotton fields can not be directly processed for textile processing. They must be processed first, and the cotton seeds in seed cotton will be removed to get lint. The initial processing is also called gin. After seed cotton is ginning, the lint percentage of the lint cotton is the percentage of the original seed weight. The lint percentage is generally 30%-40%, which is different from the initial processing method. cotton It can be divided into sawtooth cotton and roller roller cotton.

(1) sawtooth cotton: the lint cotton made from saw tooth gin is called sawtooth cotton. Zigzag cotton contains more impurities, short fiber, shorter fiber length and higher yield. But the fiber length is short, and the rolling defects are many. At present, most fine staple cotton is sawtooth gin.

(2) leather roller cotton: cotton lint made from roller roller is called cotton roller. The roller roller cotton has many impurities and short fibers, and the fiber length uniformity is poor, and the output is low. However, the fiber length operation is small, and the rolling defects are few, but there are yellow roots. Cotton roller is suitable for long staple cotton and low grade cotton.

　 Main physical and chemical properties of cotton fibers

1. length cotton fiber length refers to the distance between two ends when the fiber is stretched, and it is one of the important physical properties of cotton fiber. The length of cotton fiber is mainly determined by cotton varieties, growth conditions and initial processing. The length of cotton fiber is closely related to yarn quality and spinning process. The length of cotton fiber is long, the uniformity is good, the short pile is few, the yarn strength is high, the evenness is uniform, the yarn surface is bright and clean, Mao Yu is few.

The length of cotton fiber is uneven, and the length and distribution of cotton fibers are usually expressed by the length of the main body, the length of the quality, the evenness and the short fiber percentage. The length of the main body refers to the length of the fiber with the most content in the cotton fiber. The quality length refers to the average length of the fiber that is longer than the length of the main body. It is used to determine the roller gauge in spinning process. The percentage of short fiber is the percentage of fiber weight which is shorter than a certain length. Generally, when the short staple exceeds 15%, the yarn strength and evenness will become worse. In addition, there are length indexes such as length, span length and so on.

Two Linear density cotton fiber The linear density refers to the degree of fiber thickness, which is one of the important quality indexes of cotton fiber. It is closely related to the maturity and strength of cotton fiber. The linear density of cotton fiber is also one of the main factors determining the yarn number and yarn quality, and is related to the feel and gloss of knitted fabrics. With finer fibers, the yarn strength is high, yarn lines are good, and the finer yarn can be spun.