Overview
EN ISO 23900-6:2018 (ISO 23900-6:2015) defines a standardized film test method to assess the degree of dispersion (dispersibility) of pigments and extenders in thermoplastic polymers. The method is applicable to colourant/extender concentrates and compounds processed by extrusion (blown or cast film). Detection of specks (agglomerates, aggregates, primary particles) is performed by transmission illumination and camera inspection, with software evaluation of contrast/brightness variations.
Note: the standard does not cover unrelated defects such as gels, black specks or holes. Test results are valid only for the specific equipment, test polymer and conditions used.
Key topics and technical requirements
- Scope and applicability: Designed for concentrates and compounds in all polymers used for extrusion processes.
- Terms and definitions: Clear definitions for speck, primary particle, aggregate, agglomerate, speck size class, speck area ratio, resolution, grey level, etc.
- Principle of the method: Produce a polymer film from the test mixture, illuminate in transmission, capture images and analyse particle-related contrast differences using image analysis software.
- Test materials: Requirements for basic test polymer, concentrate/compound and test mixture preparation (pre‑conditioning and controlled processing).
- Apparatus and setup: Extruder with blown or cast film unit, downstream handling, transmission light source, camera inspection system and calibrated reference films.
- Evaluation metrics: Detection and classification by size ranges and resolution, reporting of speck area ratio (total speck area / inspected film area) and other image-derived parameters.
- Calibration and reproducibility: Use of calibration film to check parameter settings; results are comparable only when preparation, equipment and detection system are consistent.
Applications and practical value
- Quality control of pigment and extender dispersion in plastic film production.
- Comparative testing of concentrates or compounds for R&D, supplier evaluation and production troubleshooting.
- Supporting supplier specifications, incoming material inspection and product acceptance criteria.
- Useful for optimizing milling, compounding and extrusion conditions to reduce visible specks and improve aesthetic/performance properties.
Who should use this standard
- R&D and QC laboratories in plastics, pigment and masterbatch manufacturers.
- Compounders and film extruders assessing color consistency and dispersibility.
- Material engineers and testing service providers validating pigment/extender performance.
Related standards
- ISO 23900 series (Parts 1–5) - methods for dispersion assessment in plastics (two-roll milling, filter pressure value, etc.).
- ISO/TS 27687 (nanotechnologies terminology) and ISO 4618 (colourant definitions) are referenced for terms.
Keywords: EN ISO 23900-6:2018, ISO 23900-6, pigments and extenders, dispersibility, dispersion, film test, plastics, thermoplastic polymer, extrusion, speck area ratio, camera inspection, transmission illumination.