Inter-Ply Bond Measurement Standards in Recycled Paperboard Production
Inter-ply bond standards mandate TAPPI T 541 or ISO 16260 testing under strict ISO 187 conditioning to prevent converting delamination on recycled paperboard.
Inter-Ply Starch Shower
Delivery System
Liquid application systems distribute starch between plies during the web forming process to enhance internal strength. The inter-ply starch shower uses a series of nozzles to spray a cooked starch solution onto the surface of a moving wet web. It targets the interface where two layers are joined together on the paper machine.
Application Process
Precision in the spray pattern ensures an even distribution of the adhesive across the entire width of the machine. The inter-ply starch shower provides the chemical bonding needed to compensate for the lower strength of recycled fibres. Starch solids and temperature are monitored to maintain a consistent viscosity for the spray.
This treatment increases the Scott Bond values and the overall stiffness of the multi-ply board. Proper timing of the spray prevents the web from becoming too wet and breaking.
Internal Bond
Final board quality depends on the starch penetrating the surface of both plies to create a bridge. The inter-ply starch shower is a cost-effective way to improve the compression strength of corrugated medium and linerboard. It allows mills to achieve higher performance specs without increasing the basis weight.
Consistent application prevents the layers from peeling apart during the drying process.