EN 13430

Pulp Evaluation

Laboratory testing under this protocol subjects sample sheets to disintegration cycles that simulate high consistency pulping equipment used in modern paper mills. Technicians measure the percentage of rejected particles retained on a slotted screen to determine whether wet strength agents or synthetic laminates impede fiber separation. When coating weights exceed standard mill tolerances, fragment retention increases and failure rates rise across the sorting line.

Converting plants adjust starch application levels and select water soluble adhesives to maintain low reject figures during repulping trials.

Fiber Yield

Final mill acceptance depends entirely on mass balance calculations derived from initial dry weight input versus recovered dry fiber output after standardized washing steps. Converters document these yield percentages to satisfy brand owners demanding audited proof of recyclability for folding carton lines and shipping containers. Process optimization at the corrugator dictates whether recovered pulp meets the brightness and strength targets required for secondary liners.

Unbleached kraft grades routinely achieve higher recovery yields than heavily printed folding boxboards carrying metallic foils or UV coatings.