ISO 21915-1:2020 PDF

Overview

ISO 21915-1:2020 - Textiles - Qualitative and quantitative analysis of some cellulose fibres (lyocell, cupro) - Part 1 specifies fibre identification methods for cupro and lyocell using two complementary techniques: scanning electron microscopy (SEM) (based on ISO 20705) and spectral analysis (infrared spectroscopy with multivariate calibration). The standard applies only to cupro, lyocell and their blends; other fibres must first be identified (ISO/TR 11827) and removed (ISO 1833 series). It is not applicable when the fibre surface is chemically or physically damaged.

Key topics and technical requirements

• Scope & limitations
  • Identification methods are limited to cupro and lyocell and their blends.
  • Not applicable to damaged fibre surfaces.
• SEM method
  • Follow ISO 20705 principles for longitudinal imaging.
  • Specimen pretreatment: boil in water with nonionic surfactant and sodium carbonate, wash and oven-dry (105 ± 3 °C).
  • Cut fibres (~0.6 mm ± 0.2 mm) for dispersion, mount on stub, optionally sputter-coat (gold ~600–1 000 Å).
  • Recommended SEM conditions (example): accelerating voltage 10 kV, working distance 10 mm, spot size ~35, beam current 30–100 pA; magnifications typically ×4 000–×5 000 to observe surface wrinkles.
• Spectral analysis (IR) method
  • Acquire IR spectra of calibrated reference specimens.
  • Build a calibration model using Partial Least Squares (PLS) regression with dummy variables (e.g., cupro = 1, lyocell = 0).
  • Use software capable of PLS, cross-validation and reporting SEC/SECV and correlation metrics.
• Reagents & apparatus
  • Includes methanol, nonionic surfactant, sodium carbonate, grade 3 water (ISO 3696), microtome, SEM, IR spectrometer and multivariate analysis software.

Practical applications

• Textile testing laboratories performing fibre identification and verification for product labelling and regulatory compliance.
• Quality control in manufacturing to confirm use of regenerated cellulose fibres (cupro, lyocell).
• R&D and forensic textile analysis where visual/chemical differentiation between cupro and lyocell is problematic.
• Supply-chain transparency and sustainability reporting where accurate fibre identification is needed.

Who should use this standard

• Accredited textile testing labs
• Manufacturers and product developers using lyocell or cupro
• Regulatory bodies and conformity assessment organizations
• Academic and industrial researchers in textile materials

Related standards

• ISO 20705 - Quantitative microscopical analysis (SEM principles)
• ISO 1833 (all parts) - Quantitative chemical analysis (removal of other fibres)
• ISO/TR 11827 - Prior fibre identification procedures
• ISO 3696 - Water for analytical laboratory use
• ISO 2076 - Fibre definitions and terminology

ISO 21915-1:2020 is an essential reference for accurate SEM and spectral identification of lyocell and cupro, enabling reliable textile testing and clear product composition declarations.