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.
Laboratory Disintegration
Mechanical Separation
Mechanical slushing of dry pulp or paperboard in water separates bundled fibers without altering their structural dimensions. Executing laboratory disintegration standardizes pulp slurry preparation before evaluating drainage rate and sheet strength. High-speed propellers create fluid shear forces that break inter-fiber hydrogen bonds and disperse fiber flakes.
Slushing duration controls the degree of fiber bundle breakdown prior to analytical screening.
Fiber Release
Testing equipment utilizes fixed container geometry and standardized rotor speeds to replicate commercial hydrapulping mechanics on a bench scale. Standardized laboratory disintegration releases cellulose fibers from paperboard structures without causing fiber cutting or artificial surface fibrillation. Recycled papers containing wet-strength chemicals or synthetic barriers require elevated water temperature and extended slushing times.
Slush consistency remains strictly controlled to ensure uniform shear distribution across the fluid volume. Incomplete disintegration leaves unseparated fiber flakes that distort reject measurements during subsequent screening tests. Agitation time adjustments allow testing laboratories to match specific industrial pulping regimes.
Pulper Simulation
Processing conditions set specific operational bounds for evaluating pulping resistance across different paper grades. Non-disintegrating flakes indicate the presence of wet-strength polymers or water-insoluble barrier coatings. Test validity ends when mechanical shear forces break individual cellulose fibers or degrade synthetic coatings into micro-stickies.
Reliable fiber property measurement requires complete stock defibering.