Overview
ISO 2884-2:2024 - Paints and varnishes: Determination of viscosity using rotational viscometers - Part 2 specifies a general procedure for relative measurement of viscosity of paints, varnishes, related products and binders using rotational viscometers with disc or ball spindles at specified speeds. The method is intended primarily for process monitoring (for example, viscosity monitoring during thinning) and is suitable for Newtonian and non-Newtonian systems, including materials with particle dispersions.
Key topics and requirements
- Measuring assembly: a rotational viscometer with a relative geometry (disc or ball spindle), a defined container (typical 250 ml paint can), and temperature control to maintain (23 ± 0.5) °C.
- Spindles and ranges:
- Disc spindle (type 1) for relative viscosities up to 1.5 Pa·s at 200 min−1.
- Ball spindle (type 2) for viscosities up to 6.5 Pa·s (typical diameter 31.75 mm).
- Ball spindle (type 3) for viscosities up to 34 Pa·s (typical diameter 19.05 mm) at specified speeds (44 or 20 min−1).
- Containers: typical container dimensions given (nominal internal diameter ≈ 74 mm, filling aperture ≈ 61 mm). Use consistent container geometry for comparable results or recalibrate otherwise.
- Reference fluids and calibration:
- Use standard mineral oils (no silicone oils) with certified viscosities within ±5% of stated values.
- Verify the measuring assembly using three reference fluids that cover the application range; recalibrate if measured values deviate by >±5% from setpoint.
- Sampling and preparation: follow ISO 15528 (sampling) and ISO 1513 (sample preparation). Ensure homogenization, temperature equilibration and removal of air bubbles.
- Performance and repeatability:
- Perform duplicate measurements immediately after preparation.
- Repeatability requirement: two consecutive determinations by the same operator in the same lab should not deviate by more than ±5% from their mean.
- Reporting: test report must reference ISO 2884-2, include sample ID and preparation, device and calibration data, measuring profile (temperature, speeds, durations), measured values in Pa·s with rotational speed (min−1) and temperature, error analysis and any deviations.
Practical applications and users
- Quality control and production monitoring in paint, varnish and coatings manufacturing (e.g., inline or batch thinning control).
- R&D and formulation labs assessing rheological behaviour of coatings and binder systems.
- Third‑party testing laboratories preparing compliant test reports for contractual agreements.
- Rheologists and process engineers needing a standardized relative viscosity method for Newtonian/non‑Newtonian fluids and dispersions.
Related standards
- ISO 1513 - Examination and preparation of test samples
- ISO 3219-1 - Rheology vocabulary and symbols for rotational/oscillatory rheometry
- ISO 15528 - Sampling for paints, varnishes and raw materials
- ISO 2884 series - other parts in the series (see ISO website for full list)
Keywords: ISO 2884-2:2024, paints and varnishes, viscosity measurement, rotational viscometer, disc spindle, ball spindle, relative viscosity, viscosity monitoring, quality control, rheology.