Overview
EN ISO 14680-1:2006 - Paints and varnishes: Determination of pigment content - Part 1: Centrifuge method specifies a laboratory test method to determine the pigment (and extender) content of coating materials by sedimenting the solids with a centrifuge. Published by CEN as an endorsed version of ISO 14680-1:2000, this standard is intended primarily for production control and acceptance testing of solvent- and some water‑dilutable paints (it may be unsuitable for emulsion paints and certain finely divided or coloured materials).
Key topics and requirements
- Scope and principle: Dilute a representative test portion with a suitable solvent, separate insoluble solids by centrifugation, dry the sediment and calculate pigment content by mass.
- Apparatus: laboratory centrifuge (balanced swivelling buckets) capable of ~250 000 RPM-equivalent centrifugal acceleration (~25 000 g), centrifuge tubes (e.g., 50 ml), polished-ball stirrer, forced‑air drying oven at (125 ± 2) °C, analytical balance (0.001 g) and desiccator.
- Test portions and solvent volumes: Example table entries - 50 ml tube: 10 ± 0.2 g sample + ~20 ml solvent; 100 ml tube: 15 ± 0.3 g sample + ~40 ml solvent.
- Procedure highlights:
- Prepare representative samples per ISO 15528 and ISO 1513.
- Dissolve binder with appropriate solvent (e.g., xylene for solvent‑soluble, butylglycol for water‑dilutable).
- Centrifuge until supernatant is nearly clear (typically ~20 min), decant, resuspend and repeat 2–4 times.
- Dry to constant mass at 125 °C, cool in a desiccator and weigh.
- Calculation: Pigment content (%) = (m2 − m0) / (m1 − m0) × 100, where m0 = mass of empty tube, m1 = mass of tube + test portion, m2 = mass of tube + dried residue.
- Precision: For ~30% pigment content - repeatability r = 2% (95% probability, same lab/operator); reproducibility R = 4% (different labs).
- Test report must include product identification, reference to EN ISO 14680-1, solvent used, individual and mean results, deviations from the method and test date.
Applications
- Quality control during paint and varnish production to monitor pigment/load levels.
- Incoming inspection and acceptance testing by paint formulators, converters, and specifiers.
- Laboratory verification when comparing formulations or troubleshooting pigment dispersion and solids content.
- Note: exercise caution with samples containing dyestuffs, carbon black, very finely divided SiO2 or TiO2.
Related standards
Keywords: EN ISO 14680-1:2006, pigment content, centrifuge method, paints and varnishes, test method, pigments and extenders, laboratory centrifuge, paint quality control.