Overview
ISO 15063:2011 specifies a standardized near‑infrared (NIR) spectroscopy method for the determination of the hydroxyl number of polyols used in polyurethane production. The standard defines terminology, instrumentation and software capabilities, and detailed procedures for developing, evaluating and validating NIR calibration models. It covers sample handling, data collection and processing workflows and is intended for use in research, quality control, specification testing and process control where hydroxyl value is a critical formulation parameter.
Key Topics and Requirements
- Principle: Uses multivariate correlation of NIR spectra to reference hydroxyl numbers (derived from accepted chemical reference methods) to produce predictive models.
- Calibration mathematics: Supports MLR (multilinear regression), PCR (principal‑component regression) and PLS (partial least squares) as core chemometric methods.
- Calibration material selection: Materials must represent expected sample composition, cover and preferably exceed the hydroxyl number range, and be evenly distributed across that range.
- Instrumentation:
- Light sources (typically tungsten‑halogen) and detectors (e.g., PbS, PbSe, InGaAs) are described.
- Spectrometer types referenced include monochromator, filter‑wheel, AOTF, LED and FT instruments.
- Sampling systems: cuvettes, flow‑through cells, transmission/immersion probes and ATR probes.
- Software capabilities: Data logging, spectral transformations (log(1/R)), averaging, derivative treatments, multivariate regression, outlier detection, cross‑validation and model storage.
- Validation and quality control: Procedures and statistical tests for validation, estimation of precision and bias relative to reference methods, and recommendations for monitoring instrument and calibration performance.
- Limitations: Calibrations are typically instrument‑specific, limited to the chemical composition and hydroxyl range represented in the calibration set, and require careful handling for calibration transfer between instruments.
Applications and Users
ISO 15063:2011 is practical for:
- Polymer chemists and formulation scientists developing polyurethanes who need accurate hydroxyl numbers for stoichiometry.
- QC and analytical laboratories performing routine hydroxyl number testing with rapid NIR methods.
- Process control and online monitoring where rapid, non‑destructive hydroxyl estimates improve production consistency.
- Instrument vendors and chemometricians building and validating NIR calibration models for polyol analysis.
Benefits include faster testing than wet‑chemical titration, non‑destructive sampling, and integration into production control systems when models are properly validated.
Related Standards
- ISO 14900 - conventional (chemical) determination of hydroxyl number (reference method)
- ASTM E1655 - practices for infrared multivariate quantitative analysis
- See informative annexes in ISO 15063:2011 for instrument guidance (Annex C), sampling (Annex D), calibration selection (Annex E), multivariate analysis (Annex F) and statistical optimization (Annex G).
Keywords: ISO 15063, hydroxyl number, NIR spectroscopy, polyols, polyurethanes, calibration, PLS, PCR, MLR, quality control, process control.
Open preview (PDF)Plastics — Polyols for use in the production of polyurethanes — Determination of hydroxyl number by NIR spectroscopy
