SIST EN ISO 1833-6:2019 PDF

Overview

EN ISO 1833-6:2019 (ISO 1833-6:2018) defines a quantitative chemical method for determining the mass percentage of viscose, certain types of cupro, modal or lyocell in textile mixtures after removal of non‑fibrous matter. The test uses a formic acid / zinc chloride reagent to dissolve the cellulosic-type fibres and is primarily intended for mixtures of those regenerated cellulosic fibres with cotton, but is also applicable to mixtures containing polypropylene, elastolefin and melamine.

Key topics and technical requirements

• Scope & limits
  • Applicable to mixtures of viscose, certain cupro, modal or lyocell with cotton; also usable with polypropylene, elastolefin and melamine.
  • Not applicable where cotton has suffered extensive chemical degradation or where viscose/cupro/modal/lyocell is rendered incompletely soluble by permanent finishes or reactive dyes.
  • Preliminary solubility test required if cupro, modal or lyocell is present.
• Reagent composition
  • Formic acid / zinc chloride reagent: 20 g anhydrous ZnCl2 + 68 g anhydrous formic acid, made up to 100 g with water. If non‑fused zinc chloride is used, fibre solubility must be checked.
  • Dilute ammonia solution: 20 ml concentrated ammonia diluted to 1 L.
• Test conditions
  • Specimen in preheated conical flask (min. 200 ml) at 70 ± 2 °C.
  • Add 100 ml reagent per gram of specimen (preheated to 70 °C), stoppered and shaken; hold at 70 °C for 20 min with shaking at ~5 and ~15 min.
  • Filter, wash at 70 °C, then immerse residue in cold ammonia solution (~10 min) to neutralize, rinse, dry and weigh.
• Calculations & precision
  • Results calculated following ISO 1833‑1 general instructions.
  • Density (d) factors: d = 1.00 generally; cotton = 1.03, melamine = 1.01.
  • Precision: confidence limits not greater than ±2 percentage points at 95% confidence.

Applications and users

• Quality control and composition verification in textile manufacturing and finishing.
• Laboratory testing for fibre content declarations, regulatory compliance and product labelling.
• Textile research, forensic fibre analysis and certification bodies needing a standardized quantitative method.
• Useful to fiber analysts, testing laboratories, garment manufacturers and procurement teams verifying blends containing viscose/modal/lyocell and cotton or synthetic partners.

Related standards

• ISO 1833-1 - Textiles - Quantitative chemical analysis - Part 1: General principles of testing (normative reference for procedure, calculations and general requirements).

Keywords: EN ISO 1833-6:2019, ISO 1833-6, textile analysis, quantitative chemical analysis, viscose, cupro, modal, lyocell, formic acid, zinc chloride, fibre composition, cotton testing.