Overview
EN ISO 1833-12:2020 (ISO 1833-12:2020) defines a quantitative chemical analysis method for determining the mass percentage of acrylic, certain modacrylics, certain chlorofibres and certain elastane fibres in textile mixtures. The procedure uses dimethylformamide (DMF) to dissolve the target polymer fraction at elevated temperature and expresses results after removal of non‑fibrous matter. The standard applies when these fibres are blended with wool, animal hair, silk, cotton, viscose, cupro, modal, lyocell, polyamide, polyester, polypropylene, elastomultiester, elastolefin, melamine, polypropylene/polyamide bicomponent, polyacrylate or glass fibres. It excludes animal hair, wool and silk dyed with chromium‑based mordant dyes.
Key topics and technical requirements
- Analytical principle: dissolve acrylic/modacrylic/chlorofibre/elastane in DMF (90–95 °C), collect and weigh the insoluble residue; calculate target fibre percentage by difference.
- Reagent specification: use dimethylformamide with ≤0.1% water content; observe DMF safety precautions.
- Apparatus: glass conical flask (≥200 ml, stopper), water bath (90–95 °C), weighed filter crucible and suction filtration as per ISO 1833‑1.
- Test procedure highlights:
- Add 100 ml DMF per gram of specimen, heat 1 h with intermittent shaking, then a further 60 ml DMF and 30 min heating with washing and filtration steps.
- Wash residue with hot water (70–80 °C) and dry/weigh the crucible and residue.
- Calculation: follow ISO 1833‑1 general instructions; density correction factor d = 1.00 except for wool, cotton, viscose, cupro, modal, lyocell, polyamide, polyester, elastomultiester, melamine and polyacrylate where d = 1.01.
- Precision: confidence limits ≤ ±1 percentage point at 95% confidence for homogeneous mixtures.
- Limitations: perform preliminary solubility checks for some modacrylics, chlorofibres or elastanes; not suitable for certain chromium‑mordanted animal fibres.
Practical applications and users
This method is essential for:
- Textile testing laboratories performing fibre composition analysis and verification.
- Quality control teams at textile and apparel manufacturers for label accuracy and blend verification.
- Import/export compliance and customs classification requiring confirmed fibre content.
- R&D and failure analysis where accurate polymer proportions are needed.
- Recycling and material sorting operations needing reliable identification of acrylic/elastane fractions.
Users include accredited testing labs, manufacturers, auditors, regulators and researchers involved in textile analytical chemistry.
Related standards
- ISO 1833-1 - General principles of quantitative chemical analysis (reference calculations and procedures)
- ISO 1833-20 - Elastane mixtures (dimethylacetamide method)
- ISO 1833-21 - Chlorofibres/modacrylics/elastanes with cyclohexanone method
- ISO 16373-1 - Dyestuff identification for coloured textiles
Keywords: EN ISO 1833-12:2020, ISO 1833-12, textile quantitative chemical analysis, dimethylformamide, acrylic fibre testing, elastane analysis, fibre composition testing.
