The adhesive layer of the packaging adhesive tape needs to have sufficient initial tack, so as to ensure that the adhesive tape can quickly wet the surface of the carton cardboard during the high-speed automatic sealing operation, thereby forming a firm bond. In order to prevent the carton from cracking again after sealing, it is very important for the packaging adhesive tape to have a certain initial tack and the ability to wet the carton surface. As people's awareness of environmental protection increases, more and more cartons use recycled cardboard. Sometimes cardboard is recycled up to 8 times. Due to repeated processing, the fibers of this repeatedly recycled cardboard are relatively short, and this cardboard also contains other chemical additives (such as binders) and sundries. These factors not only reduce the surface roughness of recycled cardboard, but also reduce the polarity of its surface. When sealing cartons made of recycled cardboard, the initial tack and wettability of the adhesive tape will be reduced.
There are many ways to evaluate the initial tack, and the common initial tack test methods include the plane stop method and the rolling ball inclined plane stop method. The United States adopts the first method (PSTC-6), and CHINA adopts the latter method (GB/T 4852).
The stickiness reflects the initial tack performance of the adhesive tape. Although this method is neither scientific nor strict, it can truly reflect the initial tack of the adhesive tape to a certain extent. Therefore, purchasers and users often use this method to evaluate the initial bonding performance of adhesive tapes.
