Overview
EN ISO 787-7:2009 - "General methods of test for pigments and extenders - Part 7: Determination of residue on sieve - Water method - Manual procedure" - specifies a standardized laboratory procedure for measuring the residue on sieve from a sample of pigment or extender dispersed in water. The method defines sampling, apparatus, dispersion, manual sieving and washing, drying and weighing of the retained fraction, calculation of residue (percent by mass) and mandatory test-report items.
Key topics and technical requirements
- Scope: Applies to pigments and extenders dispersed in water; results can differ from the mechanical flushing procedure (ISO 787-18), so the chosen method must be stated in specifications and reports.
- Sampling: Take a representative sample per ISO 15528.
- Apparatus: metal test sieve (ISO 565) - nominal aperture must be reported (45 µm often used); brush, sintered‑glass crucible (porosity P40 per ISO 4793) or 50 ml beaker; oven at (105 ± 2) °C; balances (up to 1 000 g to 0.1 g and high‑precision to 1 mg); desiccator; washbottle.
- Test portion size: typically 10–100 g; up to 1 000 g for very low-residue products. Duplicate determinations are required.
- Dispersion: Water (300–600 ml) with an agreed dispersing agent (typically 0.2–0.5 % of test mass) or mechanical stirring per ISO 3262‑9 (stirrer speed recommended ≤ (500 ± 50) min−1). The dispersing method and agent must be reported.
- Procedure: Pour dispersion through the sieve, rinse until washings are clear, optionally break agglomerates with a brush, transfer residue to crucible/beaker, dry and weigh. If residue melting point