Optimizing Multi-Ply Layering for Enhanced Post-Consumer Containerboard Performance
Multi-ply layering of post-consumer containerboard optimizes flexural stiffness and crush resistance by concentrating long fibers in outer faces.
Disc Refining
Fibre Modification
Mechanical treatment of papermaking pulp alters the physical structure of individual wood fibres to improve their bonding capability. This treatment, known as disc refining, forces the pulp slurry through the narrow gap between rotating and stationary plates equipped with raised metal bars. The shear forces and compressions shake the fibre walls, causing fibrillation and increasing the surface area available for hydrogen bonding.
This process applies to both hardwood and softwood pulps, though each requires different disc configurations and power settings to avoid excessive fibre shortening.
Energy Application
Power consumed by the refiner motor is converted into net specific energy applied to the dry weight of the treated pulp. In disc refining, this energy transfer is governed by the rotational speed, plate pattern and pulp flow rate. Adjusting the gap between the discs regulates the intensity of the treatment, allowing the mill to balance fibre swelling against unwanted fibre cutting.
Modern mills run automated control loops that adjust the disc position in response to real-time drainage measurements to keep the pulp quality stable.
Sheet Performance
Enhanced fibre bonding translates into a finished paper with superior burst and tensile index. It also reduces the bulk and increases the density of the sheet, which improves the barrier performance of packaging grades but can reduce the opacity of printing papers.