ISO 1833-21:2019

Overview

ISO 1833-21:2019 is an international standard developed by ISO specifying a quantitative chemical analysis method for textiles. This part of the ISO 1833 series focuses on determining the mass percentage of chlorofibres, certain modacrylics, certain elastanes, acetates, and triacetates in textile mixtures. The method employs cyclohexanone as a solvent to dissolve specific fibres, enabling precise measurement of their content after removal of non-fibrous matter. This standardized procedure is essential for textile quality control, ensuring accurate fiber composition analysis in complex blended fabrics.

Key Topics

• Scope of Analysis
  The method applies to textiles composed of mixtures including:

  • Acetate, triacetate, chlorofibres
  • Certain modacrylic fibers
  • Specific types of elastanes
  • Combined with fibers such as wool, silk, cotton, polyamide, acrylic, melamine, polyacrylate, and glass fibers.

• Testing Principle
  Chlorofibres, modacrylics, elastanes, acetates, and triacetates are selectively dissolved from a known dry mass sample using cyclohexanone at near boiling temperature. The insoluble residue is then washed, dried, and weighed, allowing calculation of each component’s mass percentage.

• Reagents and Safety

  • Cyclohexanone (boiling point 156 °C), the key solvent, is flammable and toxic, requiring careful handling.
  • 50% ethanol solution is used for washing steps during the extraction process.

• Apparatus
  Essential equipment includes a hot extraction apparatus, reflux condenser, filter crucible, porous baffle, and heating device capable of sustained cyclohexanone boiling.

• Procedure Highlights

  • Extraction involves boiling with cyclohexanone for 60 minutes at a minimum of 12 extraction cycles per hour.
  • Subsequent washing of residue is done without suction between rinses, ensuring thorough separation.
  • Final weighing after drying provides data for calculation of fiber percentages.

• Calculation and Precision
  Corrections are applied for fiber types such as silk, melamine, polyacrylate, and acrylic, based on the factor d. The precision of results has a confidence limit within ±1 percentage point at 95% confidence on homogeneous mixtures.

Applications

• Textile Quality Control
  ISO 1833-21:2019 is critical for laboratories and manufacturers needing to quantify specific fiber contents in blended textiles, ensuring product compliance with specifications.

• Fiber Identification and Composition Verification
  It supports the verification of fiber blends used in garments, upholstery, industrial fabrics, and technical textiles.

• Research and Development
  Textile scientists and product developers employ this method to analyze material compositions when developing new fiber blends or testing durability and performance related to fiber content.

• Regulatory Compliance and Labeling
  Supports compliance with labeling standards that require precise disclosure of fiber composition in textile products.

Related Standards

• ISO 1833 Series
  ISO 1833-21:2019 complements other parts of the ISO 1833 series, which provide test methods for fiber mixtures, including:

  • ISO 1833-1: General principles of quantitative chemical analysis of textiles.
  • ISO 1833-13: Analysis of chlorofibre mixtures using carbon disulfide/acetone.
  • ISO 1833-17: Analysis of chlorofibres by sulfuric acid method.

• Fiber Nomenclature Standards

  • ISO 2076: Generic names for man-made fibers.
  • ISO 6938: Generic names and definitions for natural fibers.

Summary

ISO 1833-21:2019 provides a robust, accurate standard method for the quantitative analysis of complex textile blends containing chlorofibres, modacrylics, elastanes, acetates, and triacetates using cyclohexanone extraction. It is essential for ensuring high-quality textile production, facilitating material compliance, and supporting precise fiber composition analysis in the international textile industry.

Keywords: ISO 1833-21, textile fiber analysis, chlorofibres, modacrylics, elastane testing, acetate and triacetate analysis, cyclohexanone method, quantitative chemical textile analysis, fiber blend composition, textile quality control.