Overview
EN ISO 16805:2005 (identical to ISO 16805:2003) specifies the procedure for sample preparation when determining the glass transition temperature (Tg) of binders for paints and varnishes, including coating powders, using differential scanning calorimetry (DSC). The standard focuses on preparing representative, reproducible specimens; the actual DSC measurement method is given in ISO 11357-2.
Key topics and requirements
- Scope: Sample preparation for Tg determination of binders for paints and varnishes; measurement follows ISO 11357-2.
- Sampling: Take a representative sample in accordance with ISO 15528.
- Film application:
- Use a film applicator with a gap of 40 µm to 50 µm.
- Apply a wet-film thickness approximately 20 µm to 25 µm (0.8–1.0 mills/thous) or as agreed by the user.
- Substrates: Use a flat, inert, non‑porous substrate that allows easy film removal (examples: glass, PTFE, EPDM) that is inert to the binder.
- Drying: Store films under controlled atmospheric conditions until fully dry. When comparing systems, use identical drying times and conditions.
- Elevated temperature caution: Higher drying temperatures may shorten drying time but can cause thermal decomposition or crosslinking, altering Tg; select temperatures carefully.
- DSC sample preparation: After drying, place a specimen of known mass in a DSC pan ensuring good contact as specified in ISO 11357-2 (see Subclause 9.2).
- Reporting requirements: Test reports must include reference to ISO 16805, product identification (manufacturer, trade name, batch), sample preparation details (substrate, application, drying conditions, test temperature/pressure), measurement parameters and results per ISO 11357-1/2, whether onset or midpoint Tg was reported and whether first or second measurement was used, any deviations, and test date.
Applications and users
This standard is essential for:
- Paint and varnish formulators verifying polymer binder properties.
- Quality control and analytical laboratories performing routine Tg testing.
- R&D teams comparing binder formulations or processing conditions.
- Coatings manufacturers assessing the effect of solvents, drying, or curing on polymer mobility.
- Regulatory and standards bodies needing consistent, reproducible sample-preparation protocols.
Practical benefits include improved reproducibility of Tg results, consistent sample handling across labs, and reliable data to guide formulation, processing, and performance predictions.
Related standards
- ISO 11357-1: Plastics - DSC - Part 1: General principles
- ISO 11357-2: Plastics - DSC - Part 2: Determination of glass transition temperature (method for Tg measurement)
- ISO 15528: Paints, varnishes and raw materials - Sampling
Keywords: EN ISO 16805:2005, glass transition temperature, Tg, binders for paints and varnishes, DSC, differential scanning calorimetry, sample preparation, ISO 11357-2, coating powders.
