Viscoelastic Creep Compliance and Interfacial Fracture Energy in Paperboard Laminates
Creep compliance dictates long-term carton deformation, while interfacial fracture energy governs delamination under score bending and pallet loads.
Repulping Fiber Yield
Fibre Recovery
Repulping fiber yield quantifies the mass percentage of usable cellulosic material recovered from a printed packaging board after disintegration in a hydropulper. Dissolved coatings, mineral fillers, and wet strength additives wash away during the screening stages, leaving behind a targeted fraction of usable stock for subsequent paper machine integration. Mills monitor repulping fiber yield closely because short and degraded cellulose fractions slip through slotted baskets, reducing the overall mass balance of secondary loop operations.
Sizing Tolerance
Contaminants and hydrophobic surface treatments directly influence repulping fiber yield by hindering water penetration into the sheet structure during the initial wetting phase. Neutral sizing agents and high levels of alkyl ketene dimer reduce the rate of disintegration, forcing operators to extend hydropulper residence times or raise operating temperatures. Mechanical attrition must balance liberation against excessive microfribrillation, since aggressive rotor action shears cellulose chains into fines that lower drainage rates on the wire.
Loop Efficiency
Recycled folding boxboard grades depend on repulping fiber yield to establish purchasing thresholds and processing costs across secondary fibre processing facilities. Losses during deinking and fine screening dictate the quantity of virgin reinforcement pulp required to maintain burst and tensile strength specifications in the finished substrate. Economic viability relies on maximizing this recovered fraction while minimizing energy inputs, ensuring that secondary loop operations remain competitive against primary pulp alternatives.