The so called carton test is performed for every batch of adhesive at monta. First, our laboratory workers close the bottom of a recycled carton according to strict specifications: A tape strip is applied lengthwise, overlapping the carton’s front and back by 50 millimetres. Then, the carton is filled with tubes which exceed the carton’s interior height by 2 to 3 millimetres. This simulates an overfilling, leading to high restoring forces and overpressure. Next, the carton’s top is sealed in the same way as the bottom.

After being labelled with date, time and reference number, the carton is placed into our climate room. It stays there for 48 hours, facing a temperature of 40°C (+/- 2°C) and a relative air humidity of 60% (+/- 5%). These combined conditions challenge the tape as well as the carton. In addition to the overfilling, the adhesive bond is affected by the high air humidity diffusing into the carton and therefore influencing the tape and the cardboard stability both from the outside and the inside.

The test is deemed successful when the tape has not sheared off the carton during 48 hours and the sealing is still intact. The result also shows whether the applied tape is suitable for the carton, as there are differences between the various types of tape. Depending on the recycled content of the carton, its varnishing or impregnation, the user needs to choose the perfect tape for the particular application.