Grounding EUDR Forest Geolocation inside FSC Chain of Custody
EUDR compliance requires paper packaging to carry verified forest polygon coordinates through segregated chain of custody, eliminating mass balance credits.
Pulp Blend Ratio
Fibre Proportion
Fibre composition determines the strength, stiffness, and printability of paper and paperboard products. The pulp blend ratio specifies the exact percentages of different wood pulps, such as long-fibred softwood and short-fibred hardwood, used in the paper machine furnish. This mixture directly controls the physical properties of the finished sheet, balancing tensile strength with surface smoothness.
It is carefully monitored at the stock preparation stage to ensure consistency across different production runs.
Property Balance
Paper mills adjust the pulp blend ratio to tailor their products to specific printing and converting requirements. For instance, a high proportion of softwood chemical pulp increases the tear resistance and tensile strength of the sheet, which is necessary for high-speed printing presses and packaging lines. However, softwood fibres are long and can cause a rougher surface, so short hardwood fibres are blended in to fill the gaps and improve the sheet’s smoothness and opacity.
In recycled paperboards, the blend of virgin kraft pulp and recycled newspaper fibres is adjusted to balance cost, brightness, and stiffness. Changing these proportions affects the drainage rate of the slurry on the paper machine wire, which requires adjustments to the machine speed and pressing pressure. Thus, mill managers must coordinate the blend ratio with downstream machine parameters to maintain efficiency.
Operational Constraint
Availability of specific fibre types and the mechanical limitations of the mill’s refiners restrict the flexibility of these pulp mixtures. If a mill cannot source high-quality softwood pulp due to supply chain disruptions, it must increase the hardwood content and add chemical binders to compensate. This alternative blend can lower the runnability of the paper during subsequent converting operations.