Overview
ISO 1833-12:2020 - Textiles - Quantitative chemical analysis - Part 12 specifies a chemical-solvent method using dimethylformamide (DMF) to determine the mass percentage of acrylic, certain modacrylics, certain chlorofibres or certain elastane in textile blends. The method applies after removal of non‑fibrous matter and covers mixtures of these fibres with common natural and synthetic fibres (wool, animal hair, silk, cotton, viscose, cupro, modal, lyocell, polyamide, polyester, polypropylene, elastomultiester, elastolefin, melamine, polypropylene/polyamide bicomponent, polyacrylate or glass). It is not applicable to animal hair, wool or silk dyed with chromium‑based mordant dyes.
Keywords: ISO 1833-12:2020, textiles, quantitative chemical analysis, dimethylformamide, acrylic, elastane, chlorofibres.
Key topics and requirements
- Principle: target fibres are dissolved in DMF at 90–95 °C; the insoluble residue is collected, washed, dried and weighed. The percentage of dissolved fibres (acrylic/modacrylic/chlorofibre/elastane) is obtained by difference.
- Reagent: dimethylformamide (DMF) with ≤ 0.1% water; note the reagent’s boiling point (~152–154 °C) and the required safety precautions due to its toxicity.
- Apparatus: glass conical flask (≥200 ml), water bath (maintain 90–95 °C), weighed filter crucible and suction filtration as described in ISO 1833-1.
- Test procedure: typical dosing is 100 ml DMF per g specimen, heat 1 h with intermittent shaking, followed by a further 60 ml and 30 min heating; filter, wash (hot water 70–80 °C), dry and weigh residue.
- Calculation: follow ISO 1833-1 general instructions; the method uses a correction factor d = 1.00 (with d = 1.01 for several fibres including wool, cotton, viscose, polyamide, polyester, melamine and polyacrylate).
- Precision: confidence limits not greater than ±1 percentage point at the 95% confidence level on homogeneous mixtures.
- Limitations: perform preliminary solubility checks for certain modacrylics/chlorofibres/elastanes; not suitable for chromium‑mordanted wool/ silk/animal hair.
Applications and users
- Quality control laboratories verifying textile composition and label claims
- Textile manufacturers and converters for incoming material inspection and process control
- Testing laboratories supporting regulatory compliance, procurement and claims verification
- Product development and R&D for blend formulation and recycling stream characterization
- Forensic textile analysis where quantitative fibre composition is required
SEO phrases: textile testing, fibre composition analysis, solvent extraction method, DMF textile test, ISO textiles standard.
Related standards
- ISO 1833-1 - General principles for quantitative chemical analysis of textiles
- ISO 1833-20 and ISO 1833-21 - Alternative solvent methods for elastane and related fibre mixtures
- ISO 16373-1 - Dyestuff identification for coloured textiles
Safety note: DMF is hazardous-use appropriate ventilation, PPE and lab protocols.