1. Cotton transaction method

(1) Subject to the sample: mainly used in West Africa and India.

(2) Subject to the bulk cargo at the port: After the cotton arrives in the bonded area, confirm the quality of the bulk cotton on the spot.

(3) American General Standard: Mainly used in the United States and Brazil. US General Cotton Standard:

The grades are divided into GM, SM, M, SLM, LM, SGO, GO, BO

(GM=Class 1 SM=Class 2 M=Class 3…)

Fiber Length Grading:

2. Micronaire value

The micronaire value of cotton fiber is a comprehensive reflection of fiber fineness and maturity. The micronaire value of cotton fiber can be used as a comprehensive index to evaluate the intrinsic quality of cotton fiber, which directly affects the color, strength, fineness, naturalness, elasticity, moisture absorption, dyeing and so on of the fiber.

 2. Micronaire value

The micronaire value of cotton fiber is a comprehensive reflection of fiber fineness and maturity. The micronaire value of cotton fiber can be used as a comprehensive index to evaluate the intrinsic quality of cotton fiber, which directly affects the color, strength, fineness, naturalness, elasticity, moisture absorption, dyeing and so on of the fiber.

 The micronaire value is divided into three grades: A, B, and C, and grade B is the standard grade.

3. Moisture regain: Moisture regain refers to the percentage of moisture contained in cotton and fiber weight. The official standard moisture regain rate of cotton is 8.5%. In actual work, the moisture regain rate of raw cotton is generally measured by the electrical measuring method.

4. Impurity content: The national standard impurity content of sawtooth cotton is 2.5%.

5. Cotton is classified as follows:

(1) According to the physical form, cotton is divided into seed cotton and lint cotton. The cotton that cotton farmers pick from the cotton trees is called seed cotton, and the cotton after seed cotton is deseed is called lint cotton. Cotton in the usual sense refers to lint cotton.

(2) According to the length, cotton is divided into long-staple cotton and fine-staple cotton. The length of fine-staple cotton is generally 25-31 mm, and the length of long-staple cotton is more than 33 mm. my country's cotton is mainly fine-staple cotton.

(3) According to the processing machinery, cotton is divided into sawtooth cotton and ginned cotton. The lint processed by the sawtooth gin is called sawtooth cotton, and the lint processed by the roller gin is called the roller cotton. At present, the vast majority of cotton in my country's cotton market is sawtooth cotton.

(4) According to the color of cotton, cotton is divided into white cotton, yellow cotton, gray cotton and colored cotton.

(5) According to the different grades of cotton, cotton is divided into high-grade cotton and low-grade cotton.

6. Methods of cotton inspection in my country:

The sensory test is the main method, and the instrument test is supplemented. The grade, length, foreign fibers and neps are subject to the sensory test, and the micronaire value, moisture regain, impurities and short fiber rate are subject to the instrument test. The order of inspection is:

Sampling - checking moisture regain - checking impurity content - checking grade - checking length - checking micronaire value - checking foreign fibers - checking neps - checking short fiber rate.