Recycled Containerboard Compression Loss under Constant Atmospheric Humidity
Recycled containerboard loses up to 45% compression strength under constant 85% RH; specify ISO 2233 derated SCT metrics to prevent static stack collapse.
High Humidity Packaging
Material Performance
Barrier properties against moisture transfer define the capacity of substrates to maintain structural integrity and product quality when subjected to high ambient humidity. High humidity packaging incorporates specialized coatings, synthetic resins, or laminated barrier films to prevent water vapor transmission rates from exceeding critical thresholds for the contained goods. These materials stabilize paperboard or flexible substrates during sea freight or prolonged storage in tropical climates.
The barrier functions through the application of hydrophobic layers that inhibit fibre swelling and loss of tensile strength.
Converting Requirement
Manufacturing specifications for these structures demand precise control over coat weight and curing parameters during the production phase. Converting facilities utilize moisture meters and analytical scales to verify that the application of wax, polyethylene, or metallized layers provides sufficient coverage to withstand saturation cycles. Variations in the base weight of the substrate necessitate adjustments in application depth to ensure consistent performance.
Line operators monitor the mechanical properties of the packaging to avoid cracking or pinholing that would undermine the moisture resistance.
Technical Boundary
Optimal performance relies on the integrity of heat seals or adhesive bonds that join the barrier surfaces. Seam failure allows atmospheric water vapor to bypass the treated material, rendering the protective properties of the packaging ineffective. Industrial standards govern the testing of these seals through accelerated stress protocols that simulate long duration exposure to extreme dampness.
The protective efficacy remains dependent on the continuity of the coating across all folds and creases of the finished container.