Testing method for linear density of man-made filament yarns

Transcription

1 Translated English of Chinese Standard: GB/T Wayne Zheng et. al ICS W 50 National Standard of the People s Republic of China GB GB/T Replacing GB/T Testing method for linear density of man-made filament yarns 化学纤维长丝线密度试验方法 (BISFA-2004, Testing methods for polyester filament yarns, BISFA-2004, Testing methods for polyamide filament yarns, BISFA-1997, Testing methods for viscose, cupro, acetate, triacetate and lyocell filament yarns, NEQ) Issued on: June, 18, 2008 Implemented on: March, 1, 2009 Issued by: General Administration of Quality Supervision, Inspection and Quarantine; Standardization Administration Committee. Page 1 of 21

2 Table of Contents Foreword Scope Normative references Terms and definitions Test of multifilament yarn density Linear density test of monofilament (determination of multifilament number) Calculation results Data rounding Allowed errors Test Report Appendix A Appendix B Appendix C Page 2 of 21

3 Foreword Compared with BISFA standards The testing method for polyester filament yarns (2004), The testing method for nylon filament yarns (2004), and The testing method for rayon, cupra, acetate, triacetate, and lyocell filament yarn (1997), the consistency degree of linear density of this Standard is non-equivalent. This Standard replaces GB/T Testing method for linear density of synthetic fiber filament yarns. Compared with GB , the main changes are as follows: MODIFY the scope of application; EXPAND it from synthetic filament to cellulose chemical fiber filament (see Chapter 1); MODIFY the sampling requirements, SAMPLE according to parts or bulk samples (see 4.3.1); INCREASE pre-controlled humidity temperature, relative humidity and time (see ); MODIFY humidity and experimental standard atmospheric conditions and time (see ); ADD the calculation of pre-tension load (see ); ADD the half-width value of the confidence interval (± 1.5%) (see 4.3.5); ADD the test methods and calculations to the thread number determination of monofilament linear density and multifilament linear density; MODIFY the digital rounding of calculated results (see Chapter 7). Appendix C of this Standard is normative; Appendix A and Appendix B are informative. This Standard was proposed by China National Textile and Apparel Council. This Standard shall be under the jurisdiction of Shanghai Textile Industry Institute of Technical Supervision. This Standard was mainly drafted by organizations: Shanghai Textile Industry Page 3 of 21

4 Institute of Technical Supervision, Baoding Swan Chemical Fiber Co., Ltd., Xinxiang Chemical Fiber Co., Ltd., Luoyang Branch of Sinopec Group, and Jiangsu Shenghong Chemical Fiber Co., Ltd.. Main drafters of this Standard: Chen Min, Jia Sufen, Liu Chufeng, Zhang Feng, Kang Jinyang, and Yang Yan. The previous editions replaced by this Standard are: GB/T , GB/T Page 4 of 21

5 Testing method for linear density of man-made filament yarns 1 Scope This Standard specifies the testing method for linear density of filament yarns (multifilament and monofilament) such as polyester (PET), polyamide (nylon), polypropylene (PP), and cellulose chemical fibers. This Standard applies to the testing of linear density of filament yarns which are drawn from roll-packed or fabric. Strands and cables can refer to this Standard for implementation. This Standard does not apply to the filament yarns of which the elongation is greater than 0.5% when the tension increases from 0.05 cn/dtex to 0.1 cn/dtex. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this Standard. For dated reference, all the subsequent amendments (excluding corrections) or revisions do not apply to this Standard, however, it is encouraged that the parties, who reach an agreement according to this Standard, study whether the latest versions of these documents can be used. For undated references, the latest editions of the normative documents referred to apply to this Standard. GB/T Textiles - Terms of textile material properties and test - Part 3: General GB/T 6502 Sampling method of man-made filament yarns GB/T 6529 Textiles. Standard atmospheres for conditioning and testing GB/T 8170 Rules of rounding off for numerical values Page 5 of 21

6 3 Terms and definitions The following terms and definitions and those determined by GB/T apply to this Standard. 3.1 Nominal linear density Product linear density indicated in the sales contract, invoice or packaging. 4 Test of multifilament yarn density 4.1 Principle Under the specified test conditions, MEASURE the mass of the sample of which the length is known, CALCULATE the linear density. The linear density shall be represented by Tex system, the recommended unit is decitex (dtex). 4.2 Devices Strands of yarn length measuring instrument With tension-adjustable device and reciprocating filament-guiding device With speed-adjustable device so as to ensure that the tension fluctuation range is within the allowed range Yarn frame perimeter is (1.000 ± 0.002) m Device counting the number of reeling: When if returns to the initial position after one cycle. The error shall not be greater than ± 1% Single thread length measurement frame Vertical ruler: measuring range is 1 m; the minimum scale value is 1mm Devices applying pre-tension: the accuracy of applying pre-tension is Page 6 of 21

7 Some samples in the test do not comply with the normal distribution. So it is necessary to take a series of laboratory sample from batch samples to conduct independent test. Each laboratory samples shall be tested with more than one sample, and CALCULATE the arithmetic mean of single values of this laboratory samples according to the C.3. CALCULATE standard deviation of arithmetic mean of each group of single values TO the total arithmetic mean of each laboratory samples according to C.5. The confidence region of total arithmetic mean can be calculated by that standard deviation, at here the n is the number of laboratory samples to be tested. C.8 Redetermination of test number SAMPLE laboratory samples according to requirements of GB/T If they failed to achieve the required confidence region, it is necessary to increase the number of tests. If it has already done n times of test, COMPUTE the standard deviation s or coefficient of variation CV b. If it exceeds the specified confidence region, in order to reach the required half-width value of the confidence region c* or C*, the number of tests shall be increased m times, m is calculated according to the formula (C.14) or the formula (C.15): or...(c.14)...(c.15) In the formula: t The value corresponds to n in the Table C.1. In this case, CALCULATE mean and confidence region with the test results of (m + n). And INSPECT if the new confidence region meets the requirements. Page 21 of 21