Interfacial Shear Strain and Delamination Dynamics in Thermal Plastic Board Lamination
Interfacial shear strain from thermal mismatch drives delamination; controlling cooling gradients and dyne levels prevents bond failure at crease lines.
Cepi Repulpability Guidelines
Fibre Separation
Evaluation methods determine whether secondary packaging materials break down sufficiently during standard hydropulper processing to allow efficient fragment removal by sorting equipment. The cepi repulpability guidelines establish the specific laboratory testing parameters required to verify that printed folding boxboard and coated conversion grades reintegrate into aqueous mill furnish without clogging wet end screens. Slushing protocols measure disintegratability by quantifying the percentage of acceptable stock passing through a defined slot width after a fixed mechanical action cycle.
Commercial folding carton manufacturers must respect these disintegration thresholds before releasing new barrier coated substrates into high volume publication supply chains.
Adhesive Tolerance
Hot melt glues and dispersion adhesives applied during finishing operations present the primary obstruction to successful secondary fiber recovery during industrial pulping cycles. Residual binding compounds form tacky agglomerates known as stickies that deposit on paper machine felts and degrade the tensile strength of the finished newsprint or linerboard web. Testing frameworks assess stickie formation tendencies by subjecting glued carton samples to simulated alkaline cooking liquor and screening the resulting slurry through precision apertures.
Production facilities select specific adhesive formulations to minimize particle size growth and ensure complete reject removal during the macro sorting stage.
Coating Compatibility
Functional surface treatments applied to carton boards for moisture barrier properties often inhibit water penetration and slow down the initial fiber wetting phase inside the hydropulper. Laboratory procedures measure disintegration kinetics by tracking the time required for coated sheet samples to lose structural integrity under controlled thermal and hydrodynamic stress. Water based dispersions disperse readily during standard processing runs whereas extruded polyethylene layers require mechanical separation phases to isolate plastic film fractions from the aqueous fiber suspension.
Packaging designers evaluate these coating degradation rates to guarantee that finished converted products comply with regional mill acceptance criteria.