Interply Delamination Energy Thresholds during High Speed Converting of Recycled Paperboard Grades
Matching dynamic Scott Bond energy above 120 J/m² prevents high-speed folder-gluer delamination and reduces net carton cost through lower line scrap.
Polyacrylamide Strength Additives
Structural Bonding
Water-soluble synthetic polymers build internal fiber networks in papermaking wet ends by forming hydrogen bonds and ionic bridges across inter-fiber junctions. Polyacrylamide strength additives increase burst resistance, tensile energy absorption and ring crush values in recycled paperboard grades. The chemical agents function in both anionic and cationic forms to promote dry strength development without requiring elevated drying energy.
They govern sheet integrity during converting and end-use stacking loads. Their effect stops applying when fiber surfaces reach charge saturation or when wet-end conductivity interferes with polymer adsorption.
Charge Density
Cationic variants adsorb directly onto negatively charged wood pulp fibers, creating molecular bridges that resist mechanical shear. Anionic variants require dual-component systems with alum or cationic promoters to achieve effective retention on recycled fiber matrices. Polyacrylamide strength additives modify paperboard stiffness by increasing the total contact area between collapsed pulp fibers during web consolidation.
When system conductivity rises due to closed water loops, polymer coils collapse, reducing their effective hydrodynamic radius and diminishing bonding efficiency. Proper dosage control prevents charge reversal, which would otherwise disperse fine fibers and reduce retention rates on the wire.
Dosage Ceiling
Excessive polymer addition causes flocculation, which impairs sheet formation and creates localized grammage variations. Polyacrylamide strength additives lose efficacy when pulp slurries contain high levels of dissolved organic contaminants.