Our trained specialists run rolling ball tests regularly in our in-house lab. To do so, they first attach a 20 cm long sample of the tape, that is supposed to be tested, onto a sheet of scale paper. The sticky side needs to face upwards. A steel ramp is accurately placed with its end at the beginning of the scaled paper.

Then, a steel ball with a standardized weight, diameter and surface is cleaned, dried and placed with tweezers onto a defined spot at the beginning of the ramp. After releasing the brake mechanism of the ramp, the ball rolls down onto the tape strip. The distance the ball travels until it stops is the rolling ball value, measured in centimetres.

Depending on the type of adhesive used for the tape, different values are achieved. The general rule is: The shorter the distance, the better the tack. A low rolling ball value is a relevant indicator, especially for carton sealing. It implies that the adhesive connects with the carton fibres and establishes a strong bond with the substrate, immediately after the application.

Outstanding rolling ball values are frequently achieved by tapes coated with natural rubber adhesive, due to its composition and flow properties. A good tack is particularly important for a reliable carton sealing when restoring forces exert immediate force on the tape.

All mentioned procedures follow the American standards ASTM D3121 and PSTC-6 to ensure comparable results. Our short video shows a rolling ball test in our monta lab: