Polymer Barrier Coatings and Pulpability Test Standards
Polymer barrier paperboard compliance requires passing 0.15mm laboratory slot screening with under 15 percent reject mass to prevent EPR fee penalties.
Reject Fraction
Non-Recyclable Residue
Dry mass percentage of non-defibered material and synthetic films separated from slurry during pulp screening defines recycling loss metrics. Measuring the reject fraction identifies the proportion of unrecovered material discarded during laboratory or mill repulping trials. Screening devices separate coarse flakes and plastic films from acceptable cellulose fibers using slotted or perforated screen plates.
Higher reject values indicate low pulping efficiency or high contamination levels in raw paper stock.
Mass Separation
Quantitative measurement requires drying and weighing both accepted pulp and discarded residues after standardized screening cycles. A high reject fraction reduces overall fiber yield and increases solid waste disposal costs for paper mills. Polymer laminates and insoluble wet-strength resins generate significant screen residue during stock preparation.
Calculating mass balance ratios helps mills evaluate raw material quality and optimize pulper dwell times. Screening equipment efficiency dictates whether border-line flakes end up in the reject discharge or return to the pulper.
Efficiency Threshold
Product standards set upper allowable limits on screen residue mass for commercial paperboard repulpability. Excessive reject levels cause process equipment clogging and increase energy consumption in secondary pulping loops. Material assessment stops when non-fibrous contaminants exceed maximum percentage thresholds specified by recycling standards.
Low reject ratios confirm effective fiber release and high repulping suitability.