Chemi-Thermomechanical Pulp Core Optimization for Low Grammage Boxboard Manufacturing
Optimizing CTMP core sulfonation and bulk yields lower grammage boxboard that maintains flexural rigidity while reducing landed carton cost.
Cationic Starch Spray
Wet-End Deposition
Chemical surface treatments applied during wet-end paperboard forming introduce positively charged polysaccharide droplets directly onto wet fiber webs. Applying cationic starch spray between paper plies during sheet consolidation creates electrostatic bonds with negatively charged cellulose fibers. This chemical addition increases internal bond strength without requiring higher fiber mass or additional refining energy.
The chemical boundary limits application to multi-ply paperboard machines operating wet webs before final pressing steps.
Interfacial Adhesion
Starch misting systems deliver fine atomized particles through specialized spray booms mounted above the forming wire. When cationic starch spray contacts the wet mat, positive charge centers attach rapidly to anionic carboxylation sites on cellulose surfaces. This localized concentration of starch gel promotes hydrogen bonding across the inter-ply interface during subsequent press and dryer sections.
Consequently, multi-ply paperboard produced with this treatment resists delamination during high-speed converting and scoring operations. Proper droplet distribution across the machine width prevents localized damp spots that might cause web breaks or moisture streaks. Excess application causes nozzle clogging, foaming in recirculating white water systems and surface picking on dryer cylinders.
Operational Boundary
Application rates above three grams per square meter yield diminishing strength returns while increasing drainage resistance on forming wires. Temperature fluctuations in slurry lines alter starch viscosity and drop size distribution.