Overview
ISO 8130-15:2023 - Coating powders - Part 15: Rheology specifies standardized test methods to determine the rheological behaviour of coating powders both in their particulate (powder) state and in molten form. The standard defines how to measure fluidization, apparent viscosity of a fluidized bed, deaeration, cohesion strength and melt rheology using controlled rheometer-based procedures. It is intended for quality control, material characterization and process optimisation in powder coating production and application.
Key topics and technical requirements
- Scope: Methods for particulate and melt rheology of coating powders.
- Apparatus: Rheometer per ISO 3219-2 with a cylindrical cell (min. 50 mm diameter, 100 mm height). Recommended rectangular stirrer (min. 10 × 30 mm); mass flow controller for 0.05–5 l/min airflow; pressure transducer for pressure-drop measurements; disposable plate-plate geometry for melt tests.
- Sampling: Representative sampling per ISO 15528; recommended minimum sample volume for particulate rheology: 80 ml.
- Powder tests:
- Fluidization measurements performed both unstirred and stirred (airflow swept 0 → 5 l/min and back) to identify incipient and full fluidization.
- Fluidized-bed rheology: rotational speed ramp (0.1 min⁻¹ to 1 200 min⁻¹) corresponding to shear rates ~0.02 s⁻¹ to 320 s⁻¹; calculate apparent viscosity analogous to non-Newtonian fluids (dimensions per ISO 3219-2).
- Deaeration: measure pressure decay after fluidization stops.
- Cohesion strength: torque-based two-blade stirrer measurement after preconditioning; steady-state torque averaged (final data points) used for comparison.
- Melt tests: Plate-plate gap 0.5 mm, heating rate 3.5 K/min, temperature range 50 °C–180 °C, oscillatory test at 1 Hz to capture melt viscosity and gel point.
- Precision: Recommended torque accuracy: ≤1 nNm (fluidized bed) and ≤1 µNm (cohesion strength). Use fresh powder for repeatability.
Applications and who uses it
- Powder coating manufacturers and formulators - product development and stability testing.
- Quality control (QC) labs - batch acceptance and process monitoring.
- Process engineers - optimize fluidized-bed spray booths, pneumatic conveyance and storage handling.
- R&D and failure analysis - study segregation, aeration, melt flow and gelation.
- Suppliers of rheometers and test equipment - to design compliant test setups.
Related standards
Using ISO 8130-15:2023 helps ensure consistent, reproducible rheological data for powdered coatings - improving process control, product quality and the effective application of powder coating systems.
