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GB/T 40912-2021 English PDF (GBT40912-2021)

GB/T 40912-2021 English PDF (GBT40912-2021)

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GB/T 40912-2021: Textiles -- Quantitative chemical analysis -- Mixtures of polyesteramide with certain other fibers
This Document describes a method for the determination of the content of polyesteramide fibers and certain other fibers in a two-component mixture of polyesteramide fibers and other fibers after removal of non-fibrous substances by the dissolution method. This Document applies to polyesteramide and cellulose fibers (cotton, flax, ramie, hemp, viscose fiber, modal fiber, lyocell fiber, etc.), protein fibers (sheep wool, cashmere, mulberry silk, etc.), polyamide fiber, polyacrylonitrile fibers, some modacrylic fibers, some chlorinecontaining fibers or two-component mixture of some elastic fibers and polyester fibers.
GB/T 40912-2021
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.080.01
CCS W 04
Textiles – Quantitative Chemical Analysis –
Mixtures of Polyesteramide with Certain Other Fibers
ISSUED ON: OCTOBER 11, 2021
IMPLEMENTED ON: MAY 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative Reference ... 4
3 Terms and Definitions ... 4
4 Principle ... 4
5 Reagents and Materials ... 5
6 Apparatus ... 6
7 Samples ... 6
8 Mixtures of Polyesteramide Fiber and Cellulose Fibers (Cotton, Flax, Ramie, Hemp, Viscose Fiber, Modal Fiber, Lyocell Fiber, etc.) ... 6
9 Mixtures of Polyesteramide fibers and Protein Fibers (Sheep Wool, Cashmere, Mulberry silk, etc.) ... 7
10 Mixture of Polyesteramide Fibers and Polyamide Fibers ... 7
11 Mixture of Polyesteramide Fibers, and Polyacrylonitrile Fibers, Some Modacrylic Fibers, Some Chlorine-Containing Fibers or Some Elastic Fibers ... 8
12 Mixture of Polyesteramide Fiber and Polyester Fiber ... 8
13 Precision ... 9
14 Test Report ... 9
Appendix A (Informative) Identification Method of Polyesteramide Fiber ... 10 Appendix B (Normative) Quantitative Analysis Method for Mixture of Polyesteramide Fibers and Polyester Fibers (Nitrogen Content Method) ... 14
Bibliography ... 17
Textiles – Quantitative Chemical Analysis –
Mixtures of Polyesteramide with Certain Other Fibers
1 Scope
This Document describes a method for the determination of the content of polyesteramide fibers and certain other fibers in a two-component mixture of polyesteramide fibers and other fibers after removal of non-fibrous substances by the dissolution method.
This Document applies to polyesteramide and cellulose fibers (cotton, flax, ramie, hemp, viscose fiber, modal fiber, lyocell fiber, etc.), protein fibers (sheep wool, cashmere, mulberry silk, etc.), polyamide fiber, polyacrylonitrile fibers, some modacrylic fibers, some chlorine- containing fibers or two-component mixture of some elastic fibers and polyester fibers. 2 Normative Reference
The provisions in following documents become the essential provisions of this Document through reference in this Document. For the dated documents, only the versions with the dates indicated are applicable to this Document; for the undated documents, only the latest version (including all the amendments) is applicable to this Document.
GB/T 2910.1 Textiles - Quantitative Chemical Analysis - Part 1: General Principles of Testing
3 Terms and Definitions
This Document does not have the terms and definitions that shall be given. 4 Principle
After the sample is qualitatively identified, select an appropriate reagent to dissolve and remove one of the components from the mixture of known dry mass; collect the residue; wash, dry and weigh; and use the corrected mass to calculate the mass percent of the polyesteramide fibers and other fibers.
NOTE: See FZ/T 01057 series and Appendix A for qualitative identification methods, and the conventional moisture regain of polyesteramide fiber is 0.66%.
5 Reagents and Materials
Use the reagents specified in GB/T 2910.1 and 5.1~5.7, all of which are of analytically pure. 5.1 Sulfuric acid solution (mass fraction 70%): slowly add 625 mL of concentrated sulfuric acid (20 °C, density ρ=1.84 g/mL) into 400 mL of distilled water; after the solution is cooled to room temperature, dilute to 1 L with water; and the concentration of sulfuric acid solution at 20 °C is allowed to be in the range of 68%~72% (mass fraction).
5.2 Sodium hypochlorite solution: Add sodium hydroxide to the sodium hypochlorite solution with an available chlorine concentration of (35±2) g/L (about 1 mol/L); so that the content is (5±0.5) g/L. This solution can be titrated by iodometric method; and its concentration is allowed to be in the range of 0.9 mol/L ~ 1.1 mol/L.
5.3 Lithium hypochlorite solution: The available chlorine concentration is (35±2) g/L (about 1 mol/L); and the sodium hydroxide concentration is allowed to be within the range of (5±0.5) g/L, which can replace the sodium hypochlorite solution. Dissolve 100g of lithium hypochlorite containing 35% available chlorine or 115g lithium hypochlorite containing 30% available chlorine in about 700mL of water; then dissolve 5g of sodium hydroxide in 200mL of water; mix the two solutions evenly; and finally add water to dilute to 1L.
5.4 Formic acid solution (mass fraction of 80%; 20°C, density ρ=1.19g/mL): Dilute 880mL of 90% (mass fraction) formic acid (20°C, density ρ=1.20g/mL) with water to 1L; also dilute 780mL of 98%~100% (mass fraction) formic acid (20℃, density ρ=1.22g/mL) with water to 1L. The concentration of formic acid solution shall be in the range of 77%~83% (mass fraction). NOTE: Formic acid solution (mass fraction of 80%) has a density of ρ=1.186 g/mL at 20 °C. 5.5 N,N-dimethylformamide: boiling point 152℃~154℃.
Warning: N,N-dimethylformamide shall cause harm to human body, and users shall take perfect protective measures.
5.6 Dilute ammonia solution: Take 80mL of stronger ammonia water (20℃, density ρ=0.880g/mL); add water to dilute to 1L; and mix well.
Warning: Stronger ammonia water shall cause harm to the human body, and users shall take perfect protective measures.
5.7 Dilute acetic acid solution: Dilute 5mL of glacial acetic acid with water to 1L. dried, cooled and weighed.
8.2 Calculation and expression of result
The result is calculated and expressed according to the provisions of GB/T 2910.1; the d value of polyesteramide fiber is 0.99.
9 Mixtures of Polyesteramide fibers and Protein Fibers
(Sheep Wool, Cashmere, Mulberry silk, etc.)
9.1 Test procedures
Follow the general procedures specified in GB/T 2910.1, and then follow the procedures below. Put the prepared specimen into a conical flask with stopper (6.2); add 100 mL of sodium hypochlorite solution (5.2) or lithium hypochlorite solution (5.3) per gram of specimen; cover with a glass stopper; and shake the flask to fully moisten the specimen. Then shake for 40min on a constant temperature water bath oscillator (6.3) at a temperature of (20±2) °C. Filter with a glass sand core crucible of known dry mass; and wash the residue into a glass sand core crucible with a small amount of sodium hypochlorite solution (5.2) or lithium hypochlorite solution (5.3). Vacuum suction and discharge the liquid; then wash with water, neutralize with dilute acetic acid solution (5.7) in turn; and finally wash the residue with water continuously. After each wash, the liquid is drained by gravity and then by vacuum suction. Finally, the crucible and the residue are vacuum suctioned and drained, dried, cooled and weighed. 9.2 Calculation and expression of result
The result is calculated and expressed according to the provisions of GB/T 2910.1; and the d value of polyesteramide fiber is 1.00.
10 Mixture of Polyesteramide Fibers and Polyamide Fibers
10.1 Test procedures
Follow the general procedures specified in GB/T 2910.1, and then follow the procedures below. Put the prepared specimen into a conical flask with stopper (6.2); add 100 mL of formic acid solution (5.4) per gram of specimen; plug a glass stopper; shake the conical flask with stopper to fully wet the specimen; and shake for 15min on a constant temperature water bath shaker (6.3) at a temperature of (20±2)°C. Filter with a glass sand core crucible of known dry mass; rinse the conical flask (6.2) with a small amount of formic acid solution (5.4) and transfer the residue into the sand core crucible. Vacuum suction and drain the liquid; wash the residue with formic acid solution and hot water (90 ℃ ~ 95 ℃) in turn; then neutralize with dilute ammonia solution (5.6); and finally wash the residue with water. For each cleaning, the liquid shall be drained by gravity first, and then by vacuum suction. Finally, the crucible and residue are dried, cooled and weighed.
10.2 Calculation and expression of result
The result is calculated and expressed according to the provisions of GB/T 2910.1, and the d value of polyesteramide fiber is 1.00.
11 Mixture of Polyesteramide Fibers, and Polyacrylonitrile
Fibers, Some Modacrylic Fibers, Some Chlorine-Containing
Fibers or Some Elastic Fibers
11.1 Test procedures
Follow the general procedures specified in GB/T 2910.1, and then follow the procedures below. Put the prepared specimen into a conical flask with stopper (6.2); add 150 mL of N,N- dimethylformamide (5.5) per gram of specimen; cover a glass stopper; shake the flask to fully wet the specimen; shake for 1h in a constant temperature water bath oscillator (6.3) at 90℃~95℃. If the fibers such as polyacrylonitrile in the specimen are difficult to dissolve, add 50 mL of N, N-dimethylformamide (5.5). Filter with a glass sand core crucible; leave the residue in the flask; add 60 mL of N,N-dimethylformamide (5.5); and shake in a constant temperature water bath oscillator at 90 ℃ ~ 95 ℃ for 30min. Filter the residue into a glass sand core crucible; vacuum suction and drain the liquid; fill the crucible with hot water at 90 ℃ ~ 95 ℃ to wash the residue twice; wash the residue into the crucible; wash with water; and then vacuum suction and drain. Vacuum suction and drain after each draining by gravity. Finally, the crucible and residue are dried, cooled and weighed.
11.2 Calculation and expression of result
The result is calculated and expressed according to the provisions of GB/T 2910.1, and the d value of polyesteramide fiber is 1.04.
12 Mixture of Polyesteramide Fiber and Polyester Fiber
Execute in accordance with the method in Appendix B; it is not applicable to blended products containing nitrogen in dyes or finishing agents.
Appendix B
(Normative)
Quantitative Analysis Method for Mixture of Polyesteramide
Fibers and Polyester Fibers (Nitrogen Content Method)
B.1 Principle
According to the characteristics of nitrogen contained in the polyesteramide fiber, the nitrogen content analysis is carried out on the two-component mixture of polyesteramide fiber and polyester fiber from which non-fibrous substances had been removed and the dry mass was known by an elemental analyzer. According to the content of nitrogen element in fiber and pure polyesteramide fiber, calculate the content of polyesteramide fiber in the mixture. B.2 Equipment and reagents
Use the equipment specified in GB/T 2910.1, B.2.1 and B.2.2.
B.2.1 Elemental analyzer: It can analyze the nitrogen element content in the sample, which is composed of a sampling device, a combustion furnace, a reduction furnace, a mixed gas mixing part, and a detector. According to the elements contained in the sample and the test purpose, it can be divided into CHNS/CNS/S sulfur-containing mode and CHN/CN/N sulfur-free mode for testing. In N mode, the analysis accuracy of nitrogen (N) is no less than 0.1%; and the analysis accuracy of thermal conductivity detector (TCD) is higher than 40mg/kg; detection range: when the sampling amount is 0.02mg~50mg, analytical range of N element shall be 0mg~15mg.
B.2.2 Analytical balance: accuracy of 0.001mg.
B.2.3 Reagents.
B.2.3.1 Helium: purity 99.995%.
B.2.3.2 Oxygen: purity 99.995%.
B.3 Reference substance
Standard substance used to calibrate the instrument (see Table B.1), unless otherwise specified, use only chemically pure and above reagents.
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