Dynamic Fracture Mechanics of Multi Layer Paperboard Creasing under Rapid Shear Loading
Rapid shear creasing requires tailored interply delamination toughness to prevent liner fracturing while reducing folding torque on high-speed lines.
Chemical Pulp Liner
Fibrous Composition
Packaging board facing materials derived from chemically digested wood fibres form dense webs with intact cellulose chains for heavy duty container construction. Digestion through kraft liquor removes lignin while preserving long virgin fibers, producing chemical pulp liner with high tensile energy absorption across the sheet matrix. This virgin paperboard facing maintains structural integrity under static compression because delignified fibres establish dense hydrogen bonding networks during papermaking.
Fiber length remains intact without mechanical damage from recycling cycles.
Structural Resistance
Compression performance during vertical box stacking relies on fiber orientation established at the paper machine headbox. Chemical pulp liner yields plastically during scoring operations, preventing outer rupture when board blanks bend around container edges.
Moisture Conversion
Water vapor absorption reduces internal hydrogen bond density within the sheet network, altering dimensional stability during refrigerated transport or humid storage. Wet end hydrophobic sizing additives control liquid penetration, yet prolonged exposure to atmospheric humidity relaxes internal stress fields. Standard corrugating operations apply warm starch adhesives to join the facing onto corrugated fluting, which demands balanced moisture migration to prevent surface warping.
Excessive water absorption during converting weakens the fiber interface, leading to flute shadow printing defects or edge delamination under die cutting loads. Hydrophobic surface treatments mitigate these structural losses across extended supply chains.