GB/T 2910.7-2025Textiles - Quantitative chemical analysis - Part 7: Mixtures of polyamide with certain other fibers (method using formic acid) (English PDF)

Foreword

This document was drafted in accordance with the provisions of GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.

This document is Part 7 of GB/T 2910 Textiles - Quantitative chemical analysis. The following parts of GB/T 2910 have been published:

-- Part 1: General principles of testing;

-- Part 2: Ternary fibre mixture;

-- Part 3: Mixtures of acetate and certain other fibres (method using acetone);

cotton fibres (method using formic acid and zinc chloride);

-- Part 8: Mixtures of acetate and triacetate fibres (method using acetone);

-- Part 14: Mixtures of acetate and certain chlorofibres (method using acetic acid);

-- Part 18: Mixtures of silk and wool or hair (method using sulfuric acid);

-- Part 19: Mixtures of cellulose fibres and asbestos (method by heating);

triacetates and certain other fibers (method using cyclohexanone);

flax of ramie fibres (method using formic acid/zinc chloride);

-- Part 101: Mixtures of soybean protein composite fibre and certain other fibers.

This document replaces GB/T 2910.7-2009 Textiles - Quantitative chemical analysis - Part 7: Mixtures of polyamide and certain other fibres (method using formic acid). Compared with GB/T 2910.7-2009, in addition to structural adjustments and editorial changes, the main technical changes are as follows:

fiber, hemp fiber, polyethylene fiber, polyester composite elastic fiber, polyolefin elastic fiber and melamine fiber (see Chapter 1; see Chapter 1 of the 2009 edition);

fiber, ramie fiber, hemp fiber, polyethylene fiber, polyester composite elastic fiber, polyolefin elastic fiber and melamine fiber are added (see Chapter 8).

This document is modified in relation to ISO 1833-7:2017 Textiles - Quantitative chemical analysis - Part 7: Mixtures of polyamide with certain other fibres (method using formic acid).

The technical differences between this document and ISO 1833-7:2017 and their reasons are as follows:

and polyethylene fiber to meet testing needs in China (see Chapter 1; see Chapter 1 of ISO 1833-7:2017);

-- ISO 1833.1 is replaced with the normatively referenced GB/T 2910.1 for easier understanding (see Chapters 5~8; see Chapters 5~8 of ISO 1833-7:2017);

hemp fiber and polyethylene fiber (see Chapter 8) are added to make the content complete.

The following editorial changes have been made to this document:

Please note that some of the contents of this document may involve patents. The issuing organization of this document does not assume the responsibility for identifying patents.

This document was proposed by the China National Textile and Apparel Council.

This document is under the jurisdiction of the National Technical Committee on Textiles of Standardization Administration of China (SAC/TC209).

Drafting organizations of this document: Chinatesta Textile Testing & Certification Services (Shenzhen) Co., Ltd., Chinatesta Textile Testing & Certification Services Co., Ltd., Xiamen Laihe Lace Co., Ltd., Shaoxing Weisheng Color Textile Co., Ltd., Zhejiang Huzhou Weida Group Co., Ltd., Shaoxing Gold Sun Textile Co., Ltd., Fujian Unitex Textile Technology Co., Ltd., Nantong Jinyu Textile Plastic Co., Ltd., and Chinatesta Textile Testing & Certification Services (Fujian) Co., Ltd.

Main drafters of this document: Li Yan, Li Jinmei, Sui Jiaojiao, Ma Jinglin, Wu Xiaohang, Yao Yu, Lü Jing, Zhang Jinyu, Qiu Jianhao, Cao Miaosen.

The previous versions of this document and the documents it replaces are as follows:

-- This is the third revision.

Introduction

GB/T 2910 is a standard for quantitative analysis methods of textile fiber mixtures, of which Part 1 of GB/T 2910 specifies the general test rules for quantitative analysis of textile fiber mixtures, Part 2 of GB/T 2910 specifies the quantitative analysis methods for three-component fiber mixtures, and other parts of GB/T 2910 specify the quantitative analysis methods applicable to two-component mixtures of specific fibers. This document is Part 7 of GB/T 2910, which specifies the method using formic acid for determining the fiber content of a mixture of polyamide fiber and cotton, viscose fiber, cuprammonium fiber, modal fiber, lyocell fiber, flax fiber, ramie fiber, hemp fiber, polyester fiber, polyethylene fiber, polypropylene fiber, chlorinated fiber, polyacrylonitrile fiber, glass fiber, polyester composite elastic fiber, polyolefin elastic fiber, melamine fiber, sheep wool or other animal hair fiber after removing non-fiber substances.

GB/T 2910 is proposed to consist of the following parts:

-- Part 1: General principles of testing;

-- Part 2: Ternary fibre mixture;

-- Part 3: Mixtures of acetate and certain other fibres (method using acetone);

cotton fibres (method using formic acid and zinc chloride);

-- Part 8: Mixtures of acetate and triacetate fibres (method using acetone);

-- Part 14: Mixtures of acetate and certain chlorofibres (method using acetic acid);

-- Part 18: Mixtures of silk and wool or hair (method using sulfuric acid);

-- Part 19: Mixtures of cellulose fibres and asbestos (method by heating);

triacetates and certain other fibers (method using cyclohexanone);

flax of ramie fibres (method using formic acid/zinc chloride);

-- Part 101: Mixtures of soybean protein composite fibre and certain other fibers.

1 Scope

ramie fiber, hemp fiber, polyester fiber, polyethylene fiber, polypropylene fiber, chlorinated fiber, polyacrylonitrile fiber, glass fiber, polyester composite elastic fiber, polyolefin elastic fiber, melamine fiber, sheep wool or other animal hair fibers.

This document does not apply to two-component mixtures of sheep wool or other animal hair fibers, whose fiber content exceeds 25%, with polyamide fiber.

2 Normative references

The provisions of the following documents constitute the essential clauses of this document through normative references in this text. […]

3 Terms and definitions

There are no terms or definitions that require definition in this document.

4 Principle

The polyamide fiber is dissolved and removed from a mixture of known dry mass using formic acid reagent, and the residue is collected, washed, dried and weighed; the corrected mass is used to calculate its dry mass fraction in the mixture. The mass fraction of the second fiber is obtained from the difference.

5 Reagents

5.2 Dilute ammonia solution: dilute 80 mL of concentrated ammonia solution (ρ=0.88 g/mL at 20 °C) with water to 1 L.

6 Equipment

6.1 A stoppered Erlenmeyer flask with a capacity of not less than 200 mL.

7 Test steps

Follow the general procedure specified in GB/T 2910.1, and then proceed as follows.

Place the test specimen in a conical flask (6.1), add 100 mL of formic acid solution (5.1) per gram of test specimen, cover the flask with a stopper, shake the conical flask to wet the test specimen, and leave it at room temperature for 15 min, shaking it occasionally.

Use a small amount of 80% (mass fraction) formic acid solution to clean a filter crucible of known mass, filter the fibers in the conical flask, transfer the residue to the filter crucible, use a suction filter to drain the liquid, wash the residue with formic acid solution and hot water in turn, then neutralize with dilute ammonia solution (5.2), and finally wash the residue with cold water. During each washing, drain the liquid by gravity first, then use a suction filter to drain the liquid.

8 Calculation and presentation of results

The calculation and presentation of results shall be in accordance with GB/T 2910.1.

The correction coefficient for mass variation (d value) of flax fiber and hemp fiber is 1.02, the d value of melamine fiber is 1.01, and that of the rest is 1.00.

9 Precision

For a uniformly blended mixture of textile materials, the confidence limit of the test results of this method shall not exceed ±1% at a 95% confidence level.