Overview
ISO 17132:2007 - Paints and varnishes - T-bend test - specifies a standardized method for evaluating the flexibility and adhesion of an organic coating on a metallic substrate by bending a coated test panel and observing cracking or loss of adhesion. The method can be used as a pass/fail check or to determine the minimum bending diameter (or equivalent) at which cracking does not occur. Typical conditioning and test conditions are given (e.g., 16 h at 23 ± 2 °C and 50 ± 5 % RH).
Key topics and requirements
- Test principle: Bend coated panels 180° (coated side outside) around mandrels, spacer panels, or by repeated folding; inspect for cracking or flaking.
- T‑bend rating: Expressed as the minimum number of panel thicknesses (mandrel method), number of spacers (spacer method) or number of additional folds (folding method) at which no failure occurs.
- Apparatus & inspection:
- Vice with smooth jaws; optional mandrels or uncoated spacer panels.
- Magnifying glass (×5 to ×10) for visual inspection.
- Adhesive tape (6–10 N/25 mm per IEC 60454‑2) for tape pull-off adhesion check.
- Specimen preparation: Use representative samples and standard test panels prepared per ISO 1513 and ISO 1514; measure dry film thickness per ISO 2808.
- Conditioning & test environment: Default conditioning and testing at (23 ± 2) °C and (50 ± 5) % RH unless otherwise agreed.
- Evaluation: Examine bends immediately (excluding 5 mm from panel edges). Use tape pull-off or magnification to detect loss of adhesion. Report whether failures were cracking only, adhesion loss only, or both.
- Supplementary information: Test panel material/shape, coating application and drying/stoving details, film thickness, and whether the test is classification or pass/fail should be specified by contracting parties.
Applications and users
ISO 17132:2007 is used to:
- Verify flexibility and adhesion of paints, varnishes and coil coatings on metallic substrates.
- Confirm compliance with contractual or specification requirements (quality control, incoming inspection).
- Support product development and comparative performance testing in R&D.
Primary users:
- Coating and paint manufacturers
- Quality control and materials testing laboratories
- Metal fabricators and coil coaters
- Specifiers, procurement teams and standards bodies
Related standards
Keywords: ISO 17132:2007, T‑bend test, paint flexibility, adhesion test, metallic substrate, pass/fail test, minimum bending diameter, film thickness.
