Elcometer F506-20D プルオフ粘着力テスター

How to Prevent Adhesive and Cohesive Failures

Correct dolly position

Dolly and Actuator

Coating

Substrate

Incorrect dolly position

Dolly and Actuator

Coating

Substrate

Preparing the surface and dolly

1. Select an appropriate test area which is flat and has sufficient test area to attach the adhesion gauge.

2. Abrade the dolly and surface, clean both to remove any dust - minimising the risk of an ‘adhesive’ failure.

Fixing the dolly

3. Mix the adhesive correctly and apply a uniform adhesive film over the entire dolly face.

4. Test Standards require that the dolly is pulled off perpendicularly to the test surface. The dolly must therefore be adhered on to a prepared flat test surface (see images above). Apply an even pressure to the dolly to ensure that the dolly face is parallel to the test surface.

5. Remove any excess adhesive from around the dolly and allow to fully cure. Tape maybe required when applying dollies to vertical surfaces during the cure process.

6. If required, once the dolly has fully cured, score the coating around the dolly using the dolly cutter provided.

7. Attach the gauge actuator to the dolly and begin test.

Assessment of the Adhesion Test

For a valid pull test the coating must cover at least 50% of the area of the dolly face. If the glue fails and no coating is present on the dolly, or it covers less than 50% of the dolly face area, the pull-test is invalid and should be repeated.

When the coating has failed within the layer leaving the same coating on both the dolly and the test panel it is known as a ‘cohesive failure’.

‘Adhesive failures’ occur when either the coating has failed at the interface with another coating (leaving a coating on the dolly and another coating on the substrate), or when the coating has failed at the substrate (leaving the coating on the dolly and the substrate is bare).

NOTE: If the glue fails at a value above the specification then it can be reported that the adhesion exceeded the specification for this individual test.