Overview
EN ISO 2812-3:2019 - Paints and varnishes - Determination of resistance to liquids - Part 3: Method using an absorbent medium (ISO 2812-3:2019) is a CEN-adopted international test method for assessing how individual‑layer or multi‑layer coating systems resist liquids and paste‑like substances. The procedure uses an absorbent medium (filter paper or lint‑free cotton) placed on a coated test panel and covered (watch glass or Petri dish) to expose the coating to the test substance and evaluate effects on the coating and, if necessary, the substrate.
Key topics and technical requirements
- Scope: Determines resistance of coatings to liquids and paste-like products and can reveal substrate damage.
- Test specimens: Standard test panels (≈150 × 100 mm, thickness 0.7–1.0 mm) prepared and coated per ISO 1514; dry‑film thickness measured per ISO 2808.
- Conditioning: Panels conditioned at standard conditions (23 ± 2 °C and 50 ± 5 % RH) for at least 16 hours before testing.
- Test material & apparatus:
- Filter paper (≈25 mm–36 mm diameter) or lint‑free cotton wool that is chemically inert to the test substance.
- Watch glasses (~40 mm diameter) or Petri dishes (60 mm diameter × 20 mm) to cover test areas.
- Air oven for tests up to 40 °C (±3 °C control) when required.
- Procedure highlights:
- Tests performed in duplicate.
- Impregnate absorbent medium with test liquid (do not compress to remove excess), place on panel, ensure at least 10 mm clearance from panel edges and between samples, then cover.
- For viscous/paste substances, apply ~0.5 cm of substance, cover with absorbent medium and Petri dish.
- Test duration and temperature are agreed between parties and reflect end‑use conditions.
- Evaluation: Assess coating degradation and substrate damage according to agreed criteria and relevant ISO evaluation standards.
Practical applications and users
- Who uses it: paint and varnish manufacturers, quality control laboratories, R&D formulators, coating specifiers, test laboratories, certification bodies and contractors.
- Why use it:
- Compare chemical/solvent resistance of formulations.
- Verify product performance for specified end‑use environments (industrial, automotive, marine, architectural).
- Support quality control, claims substantiation and failure analysis.
- Assess compatibility of coatings with cleaning agents, fuels, oils, chemicals or food‑industry substances.
Related standards
Keywords: EN ISO 2812-3:2019, ISO 2812-3, paints and varnishes, resistance to liquids, absorbent medium, liquid resistance testing, coating test method, test panels, filter paper method.
