Interply Delamination Energy Thresholds during High Speed Converting of Recycled Paperboard Grades
Matching dynamic Scott Bond energy above 120 J/m² prevents high-speed folder-gluer delamination and reduces net carton cost through lower line scrap.
Fine Fraction Retention
Papermaking Efficiency
Percentage metric used in papermaking to evaluate the proportion of mineral fillers and fibre fragments held within the newly formed sheet. High fine fraction retention improves both the opacity of the sheet and the efficiency of the water loop in a mill. When these small particles are lost to the drain they increase the chemical load on water treatment facilities and represent wasted raw materials.
Process Control
Fibre and filler loss occurs when the openings in the forming fabric allow particles smaller than the gaps to escape before a mat is established. Controlling fine fraction retention requires a precise dosage of chemical retention aids such as polyacrylamides or inorganic microparticles that bind the fines to the longer fibres. Excessive additions of these chemicals can ruin sheet formation by causing large fibre clumps to form.
Papermakers must monitor drainage rates on the wire to ensure the drainage is not slowed down so much that it delays the entire machine run.
Quality Consequence
Inadequate holding of fine elements leads to an uneven distribution of filler across the thickness of the sheet. This asymmetry produces two-sidedness, where the top side of the paper behaves differently during printing than the bottom side. Non-uniform surface absorption can cause ink mottle or uneven gloss in high-end packaging.
Improving the retention of these fine materials reduces chemical consumption and stabilizes the surface strength of the sheet during multi-colour offset printing.