ISO 8130-7:2019

Overview

ISO 8130-7:2019 specifies a laboratory test method for determining loss of mass on stoving of coating powders (powder coatings) intended for electrostatic spraying, flock spraying or fluidized-bed application. The procedure measures total volatile matter (including water) released during heating (stoving) by weighing a test portion before and after heat treatment. The method is practical and designed to give reliable results for powders that lose around 2% by mass; accuracy decreases for larger losses. Thermogravimetric testing (ISO 11358 series) is noted as a comparative technique.

Key topics and requirements

• Test principle: Weigh a prepared test portion spread thinly in a flat dish, stove (heat) it under specified conditions, cool in a desiccator, and reweigh. Loss of mass is expressed as a percentage of the original powder mass.
• Apparatus: flat-bottom tinplate or aluminium dish (~75 mm), air-circulation oven (up to 250 °C), analytical balance (0.1 mg readability), desiccator with suitable desiccant.
• Sample and test portion: Representative sampling per ISO 15528; typical test portion is 0.50 ± 0.05 g, spread to a thickness representative of end-use application.
• Test parameters: Heating time and temperature are specified or agreed (Annex A gives common examples: long low-temperature for thermoplastic; 20–30 min at <180 °C, 180–200 °C or >200 °C for various thermosetting cure ranges).
• Reproducibility rules: Perform duplicate determinations; if results differ by more than 0.2% (absolute) repeat the test. Report the mean to 0.01%.
• Limitations: Best suited for powders with ~2% mass loss; precision data are not provided in the standard.
• Reporting: Test report must identify product, reference ISO 8130-7:2019, oven type, ambient temperature and humidity, test parameters (Annex A), individual and mean results, deviations and anomalies, and test date.

Applications and users

ISO 8130-7 is used to:

• Verify volatile content and bake-out behavior of powder coatings during R&D and quality control.
• Support product specifications, acceptance testing and supplier quality agreements.
• Evaluate thermoplastic and thermosetting powder formulations for stability, storage and cure behavior. Primary users:
• Powder coatings manufacturers and formulators
• QC/QA and R&D laboratories
• Coating applicators and specifiers
• Procurement and compliance teams assessing material conformity

Related standards

• ISO 11358 (Thermogravimetry of polymers) - comparative TG method for volatile content
• ISO 8130-14 - Vocabulary for coating powders
• ISO 15528 - Sampling for paints, varnishes and raw materials

Keywords: ISO 8130-7, coating powders, loss of mass on stoving, powder coatings test method, thermosetting, thermoplastic, volatile matter, electrostatic spraying, thermogravimetric testing.