Aqueous Dispersion Coating Chemistry Optimization for High Yield Mechanical Hydrapulping
Optimizing carboxylated acrylic dispersion coatings enables complete mechanical pulp fiber liberation while keeping screen rejects below one percent.
CTMP Board
Mechanical Composition
Chemi-thermomechanical pulp board consists of wood fibres treated with chemicals and steam followed by mechanical refining to maximize yield while retaining structural bulk. Producers create this ctmp board to provide stiffness and high caliper at a lower basis weight compared to chemical pulps. The process removes less lignin than traditional Kraft methods, which preserves the fibre length and bulk necessary for folding cartons.
High bulk allows the sheet to maintain rigidity during the converting process and subsequent filling line operations.
Surface Calibration
Converters apply pigmented coatings to the exterior of the ctmp board to improve printability and ink holdout properties. These coating layers compensate for the inherent surface roughness created by the high-yield mechanical fibre extraction. Precision in the application of binders prevents picking during high-speed offset or flexographic runs.
A smooth finish enables fine screen reproduction on packaging that demands visual clarity for retail display.
Dimensional Stability
Variations in moisture content dictate the final performance of the ctmp board in humid environments or refrigerated storage. Internal bond strength represents the key variable for preventing delamination when the material undergoes the mechanical stress of creasing and scoring. Maintaining a precise fibre orientation during the paper machine process ensures that the board resists warping when exposed to fluctuating temperature conditions.
Dense cross-linking of the sheet structure prevents the loss of mechanical integrity during the conversion cycle.