Bond Metric
Performance metrics for adhesive applications measure the strength of the bond between two layers of paper or board by observing the failure mode of the substrate. A high fiber tear percentage indicates that the glue bond is stronger than the internal strength of the paper itself. This value is expressed as the proportion of the bonded area that shows visible fibre separation when the two surfaces are pulled apart.
Adhesion Analysis
Testing involves applying a standard amount of adhesive to a sample and allowing it to cure under controlled temperature and humidity. After the set time has passed, the surfaces are separated manually or with a tensile tester. A successful bond typically shows more than eighty percent of the area covered in torn fibres, suggesting that the adhesive has deeply penetrated the surface of the board.
Factors such as the coating chemistry and the porosity of the paperboard influence this result. If the glue peels away cleanly leaving the surface intact, the bond is considered a failure.
Quality Assurance
Achieving a consistent result prevents carton failure during transport and storage. This measurement is a standard requirement for verifying that a new ink or varnish does not interfere with the sealing of the package.
