Calculating Surface Temperature Limits during High Speed Thermal Paperboard Embossing
Maximum surface temperature limits during high-speed paperboard embossing are bounded by latex binder scorching and steam-induced Z-direction blistering.
Clay Coated Folding Boxboard
Structural Profile
Multi-ply paperboard grades comprise a dense chemical pulp top layer covered by mineral pigment coatings. This composition defines clay coated folding boxboard, which features a middle layer of mechanical pulp to provide high bending stiffness. The combination of bleached chemical pulp on the outer plies and unbleached pulp in the interior creates a rigid structure.
It provides a clean, white face that receives high-quality printing.
Surface Finish
Coating density on the top surface determines the overall printability of the board. Applying a mixture of kaolin clay and synthetic binders to clay coated folding boxboard yields a uniform finish that limits ink absorption. This controlled porosity ensures that half-tone dots remain sharp during offset lithography.
Press operators rely on this stability to maintain register across multi-color runs. Smoothness and brightness remain the primary parameters evaluated on the production line. These values are measured using standard air-leak and optical tests to guarantee consistency before shipment.
The refined surface prevents issues such as ink picking and mottling during rapid runs.
Packaging Conversion
Die-cutting and creasing operations require specific mechanical properties to prevent cracking along fold lines. When converting clay coated folding boxboard, the multi-ply board must delaminate internally during creasing without tearing the top clay layer. This controlled separation allows for the formation of clean, sharp edges on high-speed cartoning lines.
Structural failure during this stage causes jams and costly downtime.