Establishing Multi-Party Supply Chain Dispute Protocols for Transit Moisture Ingress in Granular Polymers
Multi-party moisture disputes depend on ISO 15512 Method C baseline sampling at loading and container dew point tracking before silo transfer.
Thermal Breathing
Meaning
Physical mechanism where temperature changes drive air and moisture into and out of a sealed enclosure or shipping container. When raw polymer materials are shipped across different climates, thermal breathing introduces fresh moisture into the storage packaging, compromising the dryness of the resin.
Expansion Cycle
During the heat of the day, the air inside the container expands and some of it is pushed out through vents or seals. As the container cools down at night, the internal air contracts, creating a partial vacuum that draws humid outside air into the enclosure. This repetitive daily cycle acts as a pump that continuously introduces new moisture.
Moisture Accumulation
The incoming humid air can deposit liquid water onto the cool metal walls or the resin bags. Over several weeks of transit, thermal breathing results in a substantial accumulation of water inside the shipping unit. This moisture is absorbed by hygroscopic polymer pellets, rendering them unfit for moulding without extensive pre-drying that increases processing costs and production times.
Protective Strategy
Senders use high-barrier foil bags with desiccant packets to isolate the polymer from the surrounding air. Insulated container liners are also used to reduce the daily temperature swings that drive the breathing process. These measures help prevent the degradation of expensive engineering plastics.