Introduction to Phase Change Materials (PCMs)
The purpose of a complete temperature controlled packaging system is to maintain an interior thermal environment sufficient to meet the product’s temperature requirements. The system includes not only the packaging material itself, but the insulation, and passive phase change materials that hold temperature (active refrigeration systems will not be covered here).
Phase Change Materials (PCM) oscillate between solid and liquid phase within a certain temperature range. When the environment’s temperature is higher than that of the PCM, heat transfers from the surroundings to the material, which creates a cooling effect and changes PCM’s state from solid to liquid. When the environment’s temperature is lower than that of the PCM, heat transfers from the PCM to the surroundings, generating a warming effect and PCM changes back to its solid state.
That is where a PCM comes in handy. It matches the temperature of the product while it is going through it’s phase change, making it ideal for temperature sensitive applications, like:
- Life science/biologics packaging
- Pharmaceutical packaging
- Wine packaging
- Frozen and refrigerated food packaging
- Meat poultry and seafood packaging
- Dairy product packaging
How does a PCM work?
Each material has a defined temperature at which it changes state between solid and liquid. These have specific amounts of thermal energy that are absorbed while solidifying, and released while liquefying. During this process, they maintain their constant level of level phase change temperature.
The majority of PCM based cold chain refrigerants use specially developed, bio-based products made from paraffin materials or salt hydrates. Unlike ice, which occurs only at 0C (32F), these materials provide, at various temperatures, consistency of energy storage. PCMs’ store as much volumetric latent heat energy as frozen water.
To read more about PCMs, read our white paper.
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