After presenting a universal adhesive for aluminium cans at interpack, KHS decided to offer a similar product for PET bottles.
Here, too, the aim is to conserve resources by joining the beverage containers with a single adhesive spot, thereby avoiding the use of shrink wrap. This is made possible by a special process in which the adhesive is applied directly to the application.
The technology aims to reconcile three objectives: protection of the container wall from damage, easy handling and safe transport of the package.
To achieve the perfect balance in this "triangle of tension", nitrogen is added to the adhesive on the KHS Innopack Kisters NMP packaging machine before it is applied to the filled PET bottle. During application, the previously pressurised gas expands and foams the adhesive. This gives the adhesive greater elasticity, which has three advantages:
- the adhesive is compressed and released much more slowly when opened;
- there is less stress on the outer wall of the PET container when the package is opened;
- forces applied along the supply chain can be absorbed and compensated without damaging the packaging.
Furthermore, to ensure a homogeneous distribution of gas and glue, a pressure nozzle was developed with the help of modern production equipment.
The new configuration offers two further advantages when recycling PET containers. Once separated from the container, the glue dots do not leave any sticky residue and do not cause any inconvenience to the machines when depositing the bottles. In addition, foaming significantly reduces the density of the adhesive, allowing it to be easily removed during recycling.
