Interpretation Of The Revised Content And Interpretation Of The New Cotton Standard

On September 1, 2012, the new national standard GB 1103 Fine Lint Cotton jointly studied and revised by relevant national departments will be released and implemented on September 1, 2013. The biggest change of the new cotton standard is to upgrade the cotton grading from "grade" to "color", cotton Inspection will rise from traditional artificial sensory inspection to machine inspection, which can be said to be a qualitative leap from "human" to "instrument", and is of great significance for the healthy development of China's cotton industry.

The cotton grade inspection method that has been used for 40 years in China is about to become history with the introduction of the new standard. The core content of the cotton standard reform is to change the grade to the color grade: the grade is canceled, and the color grade, rolling quality indicators and inspection methods are added; Revise the color characteristic level to the color level, and clarify that the relevant terms of color level are mandatory.

In view of the existence of two different processing methods of cotton fine pile cotton, namely sawtooth processing and roller processing, and the current cotton color grading system is based on sawtooth fine pile cotton, which cannot meet the requirements of roller cotton instrumental inspection, so roller cotton still retains the grade index and its inspection method. Considering that keeping grade and color level quality indicators in a standard at the same time is not conducive to abolishing grade, it will also lead to the confusion of standard style and content by specifying grade and color level in a standard at the same time. Therefore, GB 1103 is revised into two national standards, namely GB 1103.1 Sawtooth Processing of Fine Lint Cotton and GB 1103.2 Roller Processing of Fine Lint Cotton. The sawtooth cotton standard adopts the color grading index system, and the roller cotton standard still maintains the grade index system.

　　 New standards realize a leap of "quality"

It is understood that at present, China Cotton market 98% of the fine staple cotton in circulation is sawtooth cotton. Therefore, for the revision of the new standard, people pay more attention to the changes in the content of GB 1103.1 Sawtooth Processing of Cotton Fine Linter (hereinafter referred to as the new standard).

According to the information obtained, the main changes of the new standard are as follows: the grade is cancelled, and the color grade, the quality index of the rolling worker and the inspection method are added; Modify the color characteristic level to color level, and make clear that the relevant terms of color level are mandatory; Added the definition of "white cotton, light spot dirty cotton, light yellow dyed cotton, yellow dyed cotton, main color grade, rolling quality"; The color grade division, color grading map and color grade object standard are defined; The color grade inspection is divided into sensory inspection and large capacity fast cotton fiber tester inspection; The quality division of rolling workers, the quality grading conditions of rolling workers, the quality reference indexes of rolling workers and the physical quality standards of rolling workers are defined.

In addition, it is also clear that the quality of rolling workers shall be subject to sensory inspection; Revised the definition of "official weight"; The definition and calculation method of "standard weight, standard weight lint percentage of seed cotton" are cancelled; It is clear that the quality inspection and weight inspection of wrapped cotton can be sampled, inspected and certified separately; Revised the sampling quantity of seed cotton; Clearly revise the lint slide sampling to inspection sampling before packaging; Cancelled the regulation of checking impurity content rate according to inspection unit during package by package inspection; It is specified that 30% of the randomly selected batch samples during the GB/T 6498 inspection shall be revised as the micronaire value test sample to test the micronaire value of batch samples one by one; The inspection items, inspection sequence and batch grouping rules of seed cotton and wrapped cotton were modified; It is clear that cotton quality identification is marked in the order of "cotton main color level, length level, main micronaire value level"; The range value of grading of foreign fiber content of wrapped cotton was modified; The grading code of "breaking specific strength, length uniformity index" is added; The restriction that "the length of grade 6 and grade 7 cotton is 25 mm and recorded as 25.0 mm" is removed.

　　 New cotton standard A total of 14 terms and their definitions are given. Compared with the original standard, in addition to the six terms of gross weight, net weight, official lint percentage of seed cotton, heterosexual fiber, heterosexual fiber content of wrapped cotton and hazardous sundries remaining unchanged, seven terms are added, namely, color grade, white cotton, light spot dirty cotton, light yellow dyed cotton, yellow dyed cotton, main color grade, and rolling quality.

　　 Pursue meticulous quality requirements

There are 11 quality indicators specified in the quality requirements of the new standard, which are color level, rolling quality, length, micronaire value, moisture regain, impurity content, breaking specific strength, length uniformity index, hazardous debris (foreign fiber content), reflectivity, and yellow depth. Color grade, rolling quality, length, micronaire value, breaking specific strength, length uniformity index, hazardous sundries, etc. are indicators reflecting cotton quality. Although moisture regain and impurity content are quality indicators, they are not "treated according to quality" in the new standard, but "treated according to quantity", which are used for conversion of cotton's official weight.

Color classification: according to the yellow depth of cotton, cotton can be divided into four types: white cotton, light spot dirty cotton, light yellow dyed cotton and yellow dyed cotton. White cotton is divided into 5 grades according to the light and shade degree of cotton, light spot dirty cotton into 3 grades, light yellow dyed cotton into 3 grades, yellow dyed cotton into 2 grades, 13 grades in total. It is worth noting that white cotton grade 3 is the standard color grade. The color level is represented by two digits, the first digit is the level, and the second digit is the type.

　 Color level code

Rolling quality: according to the appearance roughness of lint, the type and quantity of defects, rolling quality can be divided into three grades: good, medium and poor. The appearance of good lint is smooth, the cotton layer is fluffy and even, the degree of fiber entanglement is low, there are few fibrous seed crumbs, few neps, few sterile seeds, few broken seeds, few strands, soft seed epidermis, and few stiff pieces. The surface of medium grade lint is flat, the cotton layer is relatively uniform, and the fiber entanglement is general. The appearance of poor grade lint is uneven, the cotton layer is uneven, and the fiber entanglement is high.

Length revision: the length limit of grade 6 and grade 7 cotton has been removed. According to the original standard, the length of Grade 6 and Grade 7 cotton is 25 mm, which is recorded as 25.0 mm. 28mm is the standard length grade. The physical standard of cotton hand pull length is determined according to the average length of the upper half of cotton measured by the fiber rapid tester. That is, the cotton pulling length should be calibrated to the average length of the upper half of the cotton measured by the fiber quick tester.

Micronaire value: according to the value range of micronaire value, the new standard divides the micronaire value into three levels and five levels, and level B is the standard level of micronaire value.

　 Micronaire grading table

Moisture regain and impurity content: The new standard stipulates that the moisture regain of cotton is 8.5%, and the maximum moisture regain of cotton is 10.0%. The standard impurity content of cotton is 2.5%. In the process of standard revision, spin The department proposed that "with the improvement of cotton processing technology, under normal processing conditions, the impurity content of sawtooth cotton should be lower than 2.5%, and the standard impurity content should be revised". However, due to the lack of test data in this field at present, further research is needed in the future, and the standard will be revised after sufficient data are obtained, so the current standard remains unchanged.

Breaking specific strength: The Ministry of Agriculture has conducted a comparative study on the breaking specific strength of Chinese and American cotton in 2000. The research results show that the breaking specific strength level of Chinese and American cotton is equivalent. Therefore, this standard refers to the American Cotton Grading Manual and proposes a grading table of breaking specific strength.

Classification and code of breaking specific strength

Length uniformity index: the length uniformity index is divided into five grades: very high, high, medium, bottom, and very low, which are represented by U1, U2, U3, U4, and U5 respectively.

　　 Length uniformity index grading and code

Hazardous sundries: In order to effectively reduce the content of heterosexual fiber in cotton, the new standard puts forward stricter requirements on the classification of heterosexual fiber content in wrapped cotton on the basis of GB 1103-2007. The data used for grading are comprehensively determined according to the data provided by some textile enterprises and the opinions of relevant departments. The new standard divides the content of heterosexual fiber into four grades: "none, low, medium and high", which are respectively indicated by the first letter of the corresponding English word "N, L, M and H". In addition, the new standard stipulates that cotton processing units should paint the code of heterosexual fiber content when marking cotton bales.

　 Classification and code of heterosexual fiber content of wrapped cotton

Promote the healthy development of cotton industry

The new cotton standard pays more attention to the internal quality of cotton, and the indicators closely related to the actual production needs of cotton spinning enterprises, such as impurity content, heterosexual fiber and lint rate, are more fully reflected in the standard, which is more favorable for cotton spinning enterprises. The release and implementation of the new standard will change the traditional inspection method that relied on the sensory inspection of inspectors in the past. It will use a high-capacity cotton fiber detector to quickly inspect the cotton quality, implement the grading standard of cotton with color grade, and comprehensively realize the instrumented package by package inspection of large baled cotton, so as to realize the scientific and objective evaluation of the internal quality of cotton.

The changes of the new cotton standards involve many contents. No matter whether the changes are comprehensive or not, it is certain that the contents of these changes are summarized by relevant institutions and enterprises in the industry over many years of practice. The revised contents make up for the shortcomings of the old standards. For further promoting the development of modern agriculture and meeting the needs of the development of modern textile industry, It is of great significance to promote the healthy development of China's cotton industry.