Overview
ISO 14678:2005 - Adhesives - Determination of resistance to flow (sagging) - defines seven standardized methods to assess the resistance to flow (sagging) of adhesives after application at room temperature and during cure. The standard is intended for specification and quality control of adhesives and measures how far an applied adhesive film or plug moves under gravity (sags) before it sets.
Key Topics
- Seven test methods grouped by practical situation:
- Methods 1–3: flow/sag on vertical surfaces (wet film applicator, plug former, scraper).
- Method 4: static flow on test blocks (60° inclination option).
- Methods 5–6: flow after assembly (lap-joint flow and flow through a hole/slot).
- Method 7: flow of structural adhesive films during cure.
- Measurement and reporting
- Sagging quantified in millimetres as the maximum displacement from a reference edge.
- Results expressed as means from repeated tests (minimum three replicates).
- Test report must include test atmosphere, substrate, application method, temperature, mixing and timing, and any deviations or incidents.
- Test conditions and preparation
- Sampling and sample preparation referenced to EN ISO 15605 and EN 1067.
- Conditioning/test atmospheres and surface pretreatment must be specified (recommended default: 23 ± 2 °C and 50 ± 5 % RH).
- Safety and normal laboratory practice are required.
- Apparatus examples
- Applicators (defined gap), plug former (cylindrical cavity and plunger), scrapers, flow tester blocks and enclosures for controlled atmospheres.
Applications
ISO 14678 is used by:
- Adhesive manufacturers for product specification and R&D to control viscosity and sag behavior.
- Quality control laboratories to ensure batch consistency and conformance to performance criteria.
- Materials engineers and product designers to select adhesives suitable for vertical or overhead bonding, avoiding run-off or uneven coating.
- OEMs and specifiers who require documented resistance-to-flow data for assembly processes (before assembly, during cure, or after joint closure).
Practical use cases include coatings and sealants evaluation, structural film adhesive cure cycles, lap-joint assembly checks, and production process validation.
Related Standards
- EN ISO 15605 - Adhesives - Sampling
- EN 1067 - Adhesives - Examination and preparation of samples for testing
- EN 923 - Adhesives - Terms and definitions
These referenced documents support sampling, terminology and sample preparation required by ISO 14678.
Keywords: ISO 14678, adhesive sagging, resistance to flow, sagging test methods, adhesive testing, quality control, wet film applicator, plug former, structural adhesive films.
