Le fil de coton a une longue histoire de production et d'exportation en Chine et occupe une certaine position dans le commerce extérieur.

Specification quality of cotton yarn

(1) Specification and quality of cotton yarn:

There are 70-56, 55-44, 43-37, 36-29, 28-19, 18-17, 16-10, 9-7, 6-3 single yarn specifications for carding cotton. There are 150-131, 130-111, 110-91, 90-71, 70-56, 55-44, 43-37, 36-29, 28-19, 18-16 single yarn specifications for combed cotton.

Knitting yarn requires small twist, even yarn, to ensure that knitted cashmere is thick, elastic and warm. Weaving yarns require light weight, less weft knots and evenness.

(2) Inspection method:

 According to national standards, yarn quality is evaluated according to quality index and weight unevenness. Cotton yarn is graded according to evenness, neps and number of impurities. The quality index mainly refers to the strength of yarn, which reflects the wear resistance and durability of fabric to a certain extent. The grade of yarn mainly reflects the difference of yarn thickness and appearance defects. It directly affects the appearance of fabric, such as the uniformity of grain, clarity and the size of shadow. Yarn quality is closely related to production management, process conditions, mechanical condition, technical operation level, the quality of raw cotton and its rational use.

The technical index of cotton yarn can be found in GB/T398-93 national standard.

Cotton yarn inspection methods are as follows: GB/T398-93 Cotton Natural Colored Yarn; GB/T4743-95 Yarn Density (or Number of Yarns) Measurement Method-Skeing Method; SN/T0450-95 Export Natural Colored Cotton Yarn and Combed 

Polyester Cotton Blended Yarn Inspection Rules.

Inspection shall be carried out in accordance with the quality specifications and indicators stipulated in the trade contract.

Packaging storage and transportation

Cotton yarn can be divided into bobbin yarn and skein yarn according to different moulding purposes.The inner packing of cotton yarn is a plastic bag with labels of factory name, product name and specifications, registered trademark name, grade, weight, batch number, package number, quantity of yarn and package date.Cotton yarn is mainly packaged in cartons or plastic woven bags. The packing should be neat, dry and strong, suitable for long-distance transportation.The validity period of cotton yarn inspection is one year in the north and half a year in the south. Those exceeding the validity period must be inspected. Check the main items: mildew, moth, water, pollution, damage and so on.

Matters needing attention

Because of the different origin and batch number of cotton, the performance of cotton varies greatly. Therefore, different batches of cotton should be rationally mixed in processing. When signing the contract, attention should be paid to the clear batch of cotton yarn to prevent uneven dyeing during use.

Micron value

The micronaire value of cotton fibers is a comprehensive reflection of the fineness and maturity of cotton fibers. Different maturity will not only change the properties of cotton fibers, but also have a great impact on yarn forming process, quality and textile quality. The micronaire value of cotton fibers can be used as a comprehensive index to evaluate the intrinsic quality of cotton fibers, which directly affects the quality of cotton fibers. The color, strength, fineness, naturalness, elasticity, moisture absorption and dyeing of the fibers; the seed cotton fibers with long growth period and over maturity are thicker and have higher lint percentage, which are not suitable for spinning medium and high grade cotton yarns. Seed cotton with micronaire value ranging from 4.1 to 4.3 has shorter growth period, less maturity and lower relative lint percentage. However, it can spin medium and high grade cotton yarn because of its fineness, higher fiber sheet, more cross-section fibers and high strength.