Coupled Effect of Packaging Paper Moisture Content and Container Condensation
Many factories spend heavily on treating the products themselves but overlook the hidden carrier of packaging paper. Our measurements found that for the same batch of exported shoes, containers using ordinary packaging paper showed obvious mold spots on the inner walls of shoeboxes after 40 days of sea freight, while batches treated with iHeir-3 packaging paper anti-mold had zero mold detected. The core issue lies in the moisture content of packaging paper—when paper moisture exceeds 8%, under the condensation environment formed by day-night temperature differences in containers (e.g., dropping from 35°C to 15°C), paper fibers become an ideal culture medium for mold colonies.
Why Release-Type Fungicides Fail Here
Traditional practice involves spraying quaternary ammonium salt release-type antimicrobials on packaging paper, but such components migrate and volatilize rapidly under high temperature and humidity, with an actual protection period of less than 15 days. In contrast, iHeir-3 packaging paper anti-mold employs a non-release fungicide mechanism: active ingredients are permanently fixed on cellulose surfaces via covalent bonds, forming a physical antimicrobial layer. When mold spores contact the paper, positively charged groups on the antimicrobial layer pierce the spore cell membrane, causing content leakage and death. This process does not consume the antimicrobial itself, so the protection period aligns with the lifespan of the packaging paper.
Step-by-Step Implementation: Full-Chain Control from Paper to Container
Step 1: Packaging Paper Pretreatment. During papermaking or slitting, dilute iHeir-3 to 0.5%-1% concentration (recommended 1:200 with water), and increase paper weight by 15%-20% through dipping or spraying. The treated paper must be dried at 55°C to a moisture content ≤5%; otherwise, residual moisture dilutes the antimicrobial layer concentration.
Step 2: Simultaneous Anti-Mold Treatment of Packaging and Products. For products containing oils, such as leather and shoe materials, it is recommended to additionally coat the inner surface of packaging paper with iHeir-907 (containing thiabendazole) at a concentration of 0.3%-0.5% to inhibit mold nutrient sources from oil oxidation.
Step 3: Container Environmental Control. Before loading, place desiccants (e.g., silica gel or montmorillonite-based desiccants, dosage calculated at 50g per cubic meter) at the bottom of the container, and ensure relative humidity inside the container ≤65%. If the cargo itself has high moisture content (e.g., wood), extend pre-drying time to 48 hours.
Overlooked Details: Carton Corners and Ink Areas
Factories often overlook two blind spots:
First, at carton crease corners, where fiber structure damage makes them more prone to moisture absorption, mold incidence here is 3-5 times higher than on flat surfaces. It is recommended to spray iHeir-3 solution after creasing.
Second, ink printing areas. Proteins or starch binders in water-based inks serve as mold nutrient sources, and the ink layer hinders antimicrobial penetration. Solution: Add 0.2% iHeir-P100 (powdered fungicide) to the ink, or perform full-surface antimicrobial treatment after printing.
Additionally, exports to the EU must comply with REACH regulations. iHeir-3 has passed EU BPR certification, with an LD50 of 12.65g/kg (compared to 3g/kg for table salt), offering far higher safety than traditional fungicides.
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