GB/T 6098-2018 Test method for cotton fiber length GB/T6098-2018 |tt||Standard download decompression password: www.bzxz.net
This standard specifies the method for determining cotton fiber length using a roller analyzer. This standard is applicable to the determination of cotton fiber length indicators, including the length determination of lint cotton and semi-finished cotton strips in various spinning processes. This standard is not applicable to the length determination of fibers taken from a mixture of cotton and other fibers, and fibers taken from cotton yarn or cotton fabrics.

ICS59.060.10
National Standard of the People's Republic of China
GB/T6098—2018
Replaces GB/T6098.1—2006
Test method for length of cotton fibres
Roller analyser method
Test method for length of cotton fibres-Roller analyserPublished on February 6, 2018
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of ChinaStandardization Administration of the People's Republic of China
Implemented on September 1, 2018
GB/T6098—2018
Normative references
Terms and definitions
Instruments and tools
Standard atmosphere for testing
Extraction and preparation of test specimens||t t||Test steps
Calculation of test results
Precision
Test report:
Appendix A (Informative Appendix) Test record sheet for cotton fiber length (roller method) Appendix B (Informative Appendix)
Outlier Grubbs test method Appendix C (Informative Appendix)
Calculation of cardinality and uniformity
This standard was drafted in accordance with the rules given in GB/T1.1-2009. GB/T6098—2018
This standard has revised GB/T6098.1-2006 "Test method for cotton fiber length Part 1: Roller analyzer method", and the technical content that is still applicable in this part has been retained after the revision. This standard replaces GB/T6098.1-2006. Compared with GB/T6098.1-2006, this standard has the following major changes, except for editorial revisions:
Deleted the normative reference document GB/T5705 "Textile Terminology (Cotton Part)", added JJF (Textile) 024 "Roller Fiber Length Analyzer Calibration Specification";
Added the grouping method of 1mm group spacing, and the grouping method of 2mm group spacing can still be used; Modified the expression of the calculation formula of each length index; Deleted the original 5.3 Computer or calculation disk; Combined Chapter 5 and Chapter 6, and changed the balance to: Graduation value ≤ 0.1mg; Graduation value ≤ 0.01mg (for weighing the grouped fibers);
Added that when only the short fiber rate of cotton is measured, the division value is 1 Weighing calculation for two groups of 6mm and below and 16mm and above: 1. The precision of group test based on 1mm group interval was increased, and the precision of group test based on 2mm group interval was modified; the test report was modified;
1. The original Appendix A (Informative Appendix) * How to use the calculation disc was deleted. The original Appendix D (Informative Appendix) "Cotton fiber length (roller method) test record sheet" was modified as Appendix A (Informative Appendix) "Cotton fiber length (roller method) test record sheet": The original Appendix C (Informative Appendix) "Grubbs test method" was changed to Appendix B (Informative Appendix) \ Outlier Grubbs test method\;
The original Appendix E (Informative Appendix) "Baseline" was modified. and uniformity calculation", changed to Appendix C (Informative Appendix). This standard is under the jurisdiction of the National Technical Committee for Fiber Standardization (SAC/TC513). Drafting units of this standard: Henan Institute of Engineering, Shanghai Quality Supervision and Inspection Technology Research Institute, Shanghai Kangxin Optoelectronic Instrument Co., Ltd., Henan Fiber Inspection Bureau, Cotton Research Institute of Chinese Academy of Agricultural Sciences, Shanghai Exit-Entry Inspection and Quarantine Bureau, Nantong Fiber Inspection Institute, Henan Pingmian Textile Group Co., Ltd.
The main drafters of this standard: Zhu Jinzhong, Li Weidong, Su Yuheng, Zhu Dong, Mao Huixian, Yan Guangsong, Tang Shurong, Zhang Jianbang, Zhang Xianshun, Qiu Huimin, Peng Chengcheng, Zhou Shuxiang.
The previous versions of the standards replaced by this standard are: GB/T6098.1-1 985.GB/T6098.1—2006.1
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1 Scope
Test method for cotton fiber length
Roller analyzer method
This standard specifies the method for determining cotton fiber length using a roller analyzer. GB/T6098—2018
This standard is applicable to the determination of cotton fiber length indicators, including the length determination of lint cotton and semi-finished cotton strips in various spinning processes. This standard is not applicable to the length determination of fibers taken from a mixture of cotton and other fibers, and fibers taken from cotton yarn or cotton fabric.
2 Normative references
The following documents are indispensable for the application of this document. For any dated referenced document, only the dated version applies to this document. For any undated referenced document, its latest version (including all amendments) applies to this document. Sampling method for cotton fiber testing
GB/T 6097
Standard atmosphere for conditioning and testing textiles
GB/T6529
Rules for rounding off values ​​and expression and determination of limit valuesGB/T8170
JF (Textile) 024 Calibration specification for roller-type fiber length analyzerTerms and definitions
The following terms and definitions apply to this document
Main length
modal length
In the distribution of cotton fiber length, the length of the fiber with the largest mass or root number (also called the mode length). [GB/T3291.1—1997. Definition 2.22] 3.2
Quality length
qualitylength
In the distribution of cotton fiber length, the mass-weighted average length of each group of fibers above the main length. [GB/T5705—1985, definition 1.2.26 3.3
short fibre content
short fibre content
the percentage of the mass (or number) of short fibres shorter than a certain length limit in cotton fibres to the total mass (or number) of fibres. [GB/T5705—1985. definition 1.2.29
Note: In this standard, the length limits of short fibres are distinguished by cotton category. The limit for fine-staple cotton is 16mm and the limit for long-staple cotton is 20mm. For special varieties of cotton, the limit for length close to long-staple cotton is the limit for long-staple cotton, and vice versa, the limit for fine-staple cotton. 3.4
weighted average length of mass
average length of mass
In the distribution of cotton fibre length, the average length obtained by weighting the mass of each group of fibres. Note: Rewrite GB/T3291.1-1997, definition 2.18. 1
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GB/T6098-2018
uniformityextent
An index indicating the uniformity of cotton fiber length when tested with a roller analyzer. It is the percentage of fiber mass in the main length group and its adjacent 5mm length range to the total mass. [[GB/T5705-1985, definition 1.2.27]3.6
Uniformity of length
Uniformity of length
An index used to indicate the uniformity of cotton fiber length. It is the product of the base number and the main length. [GB/T5705-1985. Definition 1.2.28] 4 Principle
This standard is to arrange the sample into a cotton bundle with one end neatly arranged, and then use the roller jaws to control the long and short fibers to weigh them in equal intervals, determine the length distribution of cotton fibers, and calculate various length indicators. 5 Instruments and tools
Roller-type length analyzer (consisting of an analyzer and an extensor): The distance from the inner edge of the slide to the center of the output groove roller should be 9.5mm±0.1mm; after the analyzer cover is closed, the pressure applied by the spring on the leather roller should be 70N (±7N); when the analyzer pointer is at the 16th grid of the worm gear scale, the peach-shaped eccentric wheel should begin to contact the slide. According to the JJF (Textile) 024 metrological characteristics requirements, the compliance is determined to be qualified. 5.2 Limiter flannel board, No. 1 clamp (the clamp mouth should be straight and without gaps, and should be used in conjunction with the analyzer), No. 2 clamp (the flannel should not be worn or bald, and the spring pressure should be 2N), pads, pressure plates, sparse combs (10 needles/cm), dense combs (20 needles/cm), pointed tweezers, 50mm small steel ruler, black flannel board.
5.3 Balance: graduation value ≤0.1mg; graduation value ≤0.01mg is used for weighing the grouped fibers). 6 Standard atmosphere for testing
The standard atmosphere for testing should comply with the standard provisions in GB/T6529. 7 Extraction and preparation of test samples
7.1 Extraction of test samples
According to the provisions of GB/T6097, test samples are taken from the test cotton strips. The mass of each test sample is (30±1) mg for fine-staple cotton and (35±1) mg for long-staple cotton.
7.2 Preparation of test samples
7.2.1 Arrange the test samples. Arrange the fibers by hand for 2 to 3 times to form a relatively straight cotton bundle with one end neat. 7.2.2 Hold the neat end of the cotton tuft, place the jaw of the No. 1 clamp close to the group of metal sheets behind the limiter velvet board, and clamp the fibers from long to short in layers, and arrange them on the limiter velvet board. The neat end should extend 2mm beyond the previous group of metal sheets. Repeat this process twice to form a cotton tuft with a width of 32mm, a neat and straight end, uniform thickness, and clear layers. 7.2.3 During the sorting process, the uneven end of the cotton tuft can be gently combed several times with a sparse comb. The free fibers combed off should still be sorted and put into the cotton tuft. The fibers shorter than 8.5mm are collected separately and added to the group median 8mm fibers (Group 1) when grouping; when grouping according to the 2mm group spacing, the fibers shorter than 9mm are collected separately and added to the group median 9.5mm fibers (Group 1) when grouping. 2
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7.2.4 During the entire process of making cotton tufts, fibers must not be discarded. 8 Test steps
8.1 Lift the cover of the analyzer and shake the handle to make the 9th scale on the worm wheel coincide with the pointer. GB/T6098—2018
8.2 Use the No. 1 clamp to pick up the cotton bundle on the limiter velvet board and move it to the analyzer groove roller. When moving, the baffle under the No. 1 clamp should be close to the slide plate, and the No. 1 clamp should be supported by a horizontal pad to make the cotton bundle reach a horizontal level. Put down the cover with the pressure roller, remove the No. 1 clamp, the neat end of the fiber should be flush with the inner edge of the slide plate, and tighten the spring. If the slide plate is put down, the fiber shorter than 9.5mm will not be held by the analyzer. 8.3 If the grouping is based on a 2mm group spacing, turn the handle one circle first, then the 10th scale on the worm wheel will coincide with the pointer, and the roller will send the fiber out 1mm. At this time, if the slide plate is put down, the fiber shorter than 10.5mm will not be held by the instrument. 8.4 Use the No. 2 clamp to clamp the fibers that are not held twice. For the third time, you can clamp the free fibers that are exposed at one neat end, place them on the flannel board, and rub them into strips or rings (depending on the balance pan or hook). This is the second group of fibers. 8.5 After that, every time the handle is turned once (if grouped by 2mm group spacing, it is 2 times), use the above method to clamp the fibers that are out of the grip and collect them on the flannel board. When the pointer coincides with the 16th scale of the worm gear, lift the slide. After that, the No. 2 clamp should be clamped against the edge of the slide to clamp the fibers.
8.6 Weigh each group of fibers on the balance (accurate to 0.01mg) and record it in the "Cotton Fiber Length (Roller Method) Test Record" (see Appendix A).
8.7 Number of tests: Test each test sliver twice. The difference between the two test results should meet the requirements of Chapter 10 on precision. 8.8 When only the short fiber rate of cotton is measured, for each test sample, the analyzer pointer is directly moved to the position where it coincides with the 16th scale of the worm wheel, and the lengths of 16 mm and below and above 16 mm are weighed in two groups, and recorded in the "Cotton Fiber Length (Roller Method) Test Record Sheet" (see Appendix A). 9 Calculation of Test Results
9.1 True Mass
The mass of each group of fibers measured above is the apparent mass, which includes part of the fibers of the upper and lower adjacent length groups, so the apparent mass of each group should be corrected to obtain the true mass. The true mass is calculated according to formula (1):
m,=0.17mj-1+0.46mj+0.37mj+1
wherein:
is the true mass (abbreviated as mass) of the fiber group with a length of L (mm), in milligrams (mg); the grouping number of each fiber group, j=12,3,,k (the grouping number of the longest fiber group); the apparent mass of the previous group of fibers of the jth group (shorter than the fibers of the jth group), in milligrams (mg); the apparent mass of the fibers of the ith group, in milligrams (mg); the apparent mass of the next group of fibers of the ith group (longer than the fibers of the ith group), in milligrams (mg). The difference between the total true mass and the total apparent mass should not exceed 1 mg. 9.2 Main body length
The main body length is calculated according to formula (2):
Wherein:
Lm=(L.-0.5d)+(m,-m.)+(m.-ma+)d(mm-)
Main body length, in millimeters (mm);Order number of the heaviest fiber group;
·(2)
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GB/T6098—2018
Length of the heaviest fiber group (group median), in millimeters (mm):Group distance, 1mm or 2mm:
Mass of the heaviest fiber group, in milligrams (mg);Mass of the previous group of fibers of the heaviest fiber group, in milligrams (mg);Mass of the next group of fibers of the heaviest fiber group, in milligrams (mg). 9.3 Quality length
Quality length is calculated according to formula (3) and formula (4): Lp=L
Where: bzxZ.net
Quality length, in millimeter (mm); n)dm
The mass of the part of the fiber in the mass-maximum group whose length exceeds the main body length L㎡, in milligram (mg). 9.4 Short fiber rate
Short fiber rate is calculated according to formula (5) or formula (6): Zmi
Where:
Where:
Short fiber rate, %;
Order number of short fiber limit group.
Short fiber rate, %:
The mass of short fibers not longer than 16 mm (fine-staple cotton) or 20 mm (long-staple cotton), in milligram (mg); the mass of long fibers longer than 16 mm (fine-staple cotton) or 20 mm (long-staple cotton), in milligram (mg). Mass average length
The mass average length is calculated according to formula (7):
Where:
Mass average length, in millimeters (mm); the median value of the fiber length of the i-th group, in millimeters (mm) (5)
(6)
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9.6 Length standard deviation and coefficient of variation
The length standard deviation and coefficient of variation are calculated according to formulas (8) and (9): Am,
Where:
Length standard deviation, in millimeters (mm); CV——length coefficient of variation, %.
9.7 Numerical rounding
GB/T6098—2018
(8)
·(9)
The calculation results of each length index are rounded to one decimal place: the length standard deviation is rounded to two decimal places. The numerical rounding is carried out in accordance with GB/T8170.
10 Precision
10.1 Repeatability
Using the test method of this standard, for the same laboratory sample, under the same conditions (same laboratory, same operator, same equipment and within a short time interval), the absolute value of the difference between the main length results should be less than the repeatability limit r value at a 95% probability level. When grouped by 1mm group interval, the r value is equal to 4.34mm; when grouped by 2mm group interval, the rl value is equal to 2.55mm
Using the test method of this standard, for the same test cotton strip, two test specimens are made and tested under the same conditions (same laboratory, same operator, same equipment and within a short time interval). The absolute value of the difference between the main length results should be less than the repeatability limit r2 value at a 95% probability level. When grouped by 1mm interval, the r2 value is equal to 2.60mm; when grouped by 2mm interval, the r2 value is equal to 4.34mm.
If the absolute value of the difference in the test results of two test samples of the same test cotton strip under repeatability conditions in the same laboratory is greater than 2.60mm (when grouped by 1mm interval) or 4.34mm (when grouped by 2mm interval), an additional test should be conducted. Use the Grubbs method (see Appendix B) to test the test results of the three test samples for outliers. If there are outliers, the average of the two remaining results after eliminating the outliers is used as the final test result. If there are no outliers, the critical value of 3.26mm (when grouped by 1mm interval) or 2.37mm (when grouped by 2mm interval) is used for judgment. If the range of the test results of the three test samples is less than this critical value, the average of the three results is taken as the final test result. If it is greater than this critical value, the test is continued once more, and the test results are tested for outliers using the Grubbs method. The average of all results after eliminating outliers is taken as the final test result.2 Reproducibility
Using the test method of this standard, for the same laboratory sample, a single test is completed under different conditions (different laboratories, different operators and different equipment), and the absolute value of the difference between the main body length results should be less than the reproducibility limit R value at a 95% probability level. When grouped by 1mm interval, the R value is equal to 4.38mm; when grouped by 2mm interval, the R value is equal to 4.22mm. Using the test method of this standard, for the same test sliver, a single test specimen is prepared for testing under different conditions (different laboratories, different operators and different equipment), and the absolute value of the difference between the main body length results should be less than the reproducibility limit R value at a 95% probability level. When grouped by 1mm interval, the R2 value is equal to 4.62mm; when grouped by 2mm interval, the R value is equal to 4.38mm. 5
GB/T6098—2018
If the test results of two laboratories each contain two test specimens, the absolute value of the difference between the test results of the two laboratories should be less than 3.69mm (when grouped by 1mm interval) or 3.99mm (when grouped by 2mm interval). 11 Test report
The test report includes the length index (if the reference index base and average hook are required, the calculation is shown in Appendix C), and the batch source, batch number, test date, temperature and humidity conditions, group interval and reference standard are stated. See Appendix A for the test report. 6
Appendix A
(Informative Appendix)
Record sheet for test of cotton fiber length (roller method) See Table A.1 to Table A.3 for test record sheet of cotton fiber length (roller method). 1 Record sheet for grouping by 1mm group interval Table A.1
Sample number
Instrument model/number
Temperature (℃)
Based on standard
Grouping number;
Worm scale
Sample source
Balance model/number
Relative humidity (%)
Each group Fiber
Length range/mm
8.50~9.49
9.50~10.49
10.50~11.49
11.50~12.49
12.50~13.49
13.50~14.49
14.50~15.49
15.50~16.49
16.50~17.49
17.50~18.49
18.50~19.49
19.50~20.49
20.5021.49
21.5022.49
22.50~23.49
23.5024.49
24.50~25.49
25.50~26.49
2 6.50~27.49
27.5028.49
28.50~29.49
29.50~30.49
30.50~31.4 9
Median value of each group
Each group of fibers
Weighed mass
Quality mark
Each group of fibers
True mass
GB/T6098—2018
Calculation result
Main length/mm
Quality length/mm
Short pile rate/%
Average length/mm
Base number/%
Average hook
GB/T6098—2018
Grouping ordinal number;
Worm gear Scale
Re-test date
Sample number
Instrument model/number
Temperature (℃)
According to standard
Grouping number;
Worm gear scale
Each group of fibers
Length range/mm
31.50~32.49
32.50~33.49
33.50~34.49
34.50~35.49
35.50~36.49
36.50 ~37.49
37.5038.49
38.5039.49
39.50~40.49
40.50~41.49
41.50~42.49
Table A.1 (continued)
Median value of each group
Each group of fibers
Weighed mass
Each group of fibers
True mass
Record sheet for grouping by 2mm interval
Source of sample
Balance model/number| |tt||Relative humidity (%)
Fiber length range of each group/mm
8.5010.49
10.50~12.49
12.50~14.49
14.50~16.49
16.50~18.49
18.50~20.49
20.50~22.49
22.50~24.49
24.5026.49
26.50~2 8.49
28.50~30.49
Median of each group
Weighed mass of each group of fibers
Quality mark
True mass of each group of fibers
am;/mg
Calculation result
Standard deviation/mm
Coefficient of variation/%
Calculation result
Main length/mm
Quality length/mm
Short fiber rate/%
Average length/mm
Base number/%49
24.50~25.49
25.50~26.49
26.50~27.49
27.5028.49
28.50~29.49
29.50~30.49| |tt||30.50~31.49
Median value of each group
Each group Fiber
Average mass
Quality mark
Each group of fibers
True mass
GB/T6098—2018
Calculation results
Main body length/mm
Quality length/mm
Short pile rate/%
Average length/mm
Base number/%
all Degree
GB/T6098—2018
Grouping number;
Worm scale
Re-test date
Sample number
Instrument model/ No.
Temperature (℃)
According to standard
Grouping number;
Worm scale
Length range of each group of fibers Circumference/mm
31.50~32.49
32.50~33.49
33.50~34.49
34.50~35.49
35.50~36.49
36.50~ 37.49
37.5038.49
38.5039.49|| tt||39.50~40.49
40.50~41.49
41.50~42.49
Table A.1 (continued)
Median of each group

Weighed mass of each group of fibers
True mass of each group of fibers
Record sheet for grouping by 2mm interval||t t||Source of samples
Balance model/number
Relative humidity (%)
Fiber length range of each group/mm
8.5010.49
10.50~12.49
12.50~14.49
14.50~16.49
16.50~18.49
18.50~20.49
20.50~22.49
22.50~24.49
24.5026.49
26.50~28.49
28.50~30.49|| tt||Median value of each group
Weight of fiber in each group
Weight Quantity identification
True mass of each group of fibers
am;/mg
Calculation result
Standard deviation/mm
Coefficient of variation /%
Calculation results
Main body length/mm
Quality length/mm
Short pile rate/%
Average length/mm||tt| |Base/%49
24.50~25.49
25.50~26.49
26.50~27.49
27.5028.49
28.50~29.49
29.50~30.49| |tt||30.50~31.49
Median value of each group
Each group Fiber
Average mass
Quality mark
Each group of fibers
True mass
GB/T6098—2018
Calculation results
Main body length/mm
Quality length/mm
Short pile rate/%
Average length/mm
Base number/%
all Degree
GB/T6098—2018
Grouping number;
Worm scale
Re-test date
Sample number
Instrument model/ No.
Temperature (℃)
According to standard
Grouping number;
Worm scale
Length range of each group of fibers Circumference/mm
31.50~32.49
32.50~33.49
33.50~34.49
34.50~35.49
35.50~36.49
36.50~ 37.49
37.5038.49
38.5039.49|| tt||39.50~40.49
40.50~41.49
41.50~42.49
Table A.1 (continued)
Median of each group

Weighed mass of each group of fibers
True mass of each group of fibers
Record sheet for grouping by 2mm interval||t t||Source of samples
Balance model/number
Relative humidity (%)
Fiber length range of each group/mm
8.5010.49
10.50~12.49
12.50~14.49
14.50~16.49
16.50~18.49
18.50~20.49
20.50~22.49
22.50~24.49
24.5026.49
26.50~28.49
28.50~30.49|| tt||Median value of each group
Weight of fiber in each group
Weight Quantity identification
True mass of each group of fibers
am;/mg
Calculation result
Standard deviation/mm
Coefficient of variation /%
Calculation results
Main body length/mm
Quality length/mm
Short pile ratio/%
Average length/mm||tt| |Base/%
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