Paperboard Middle Ply Furnish Compression Mechanics under Static Bench Conditions
Middle ply CTMP bulk provides structural moment of inertia, while short-span compression bench testing quantifies network collapse risks under load.
Virgin Softwood Kraft
Primary Fiber
Long-fibered pulp produced from coniferous trees using the sulfate process offers the highest strength levels available for paper and board manufacturing. High-grade virgin softwood kraft provides the structural foundation for heavy-duty liners and high-performance folding cartons. It remains unprocessed.
The fibers ensure maximum bonding potential between the cellulose chains.
Chemical Processing
Cooking the wood chips in a solution of sodium hydroxide and sodium sulfide dissolves the lignin while leaving the long cellulose fibers intact. This virgin softwood kraft is characterized by its high tear resistance and burst strength, which are essential for packaging that must survive rough handling. The lack of prior mechanical stress means the fibers retain their full length and flexibility during the sheet-forming process.
High chemical purity ensures that the bonds remain strong even after the material is exposed to environmental stress.
Strength Application
Incorporating this grade into a multi-ply board construction allows manufacturers to meet strict performance requirements with less total material. When the virgin softwood kraft is used in the outer layers, it provides a smooth and durable surface for high-quality printing and finishing. This fiber remains the preferred choice for applications where the failure of the package could lead to product damage or safety hazards during transit.