The same container bounces when dropped at room temperature and can crack from the same fall in a freezer store. As temperature falls, the movement of the polymer chains slows; the material stiffens and concentrates the impact energy at one point instead of spreading it.
The temperature of that change depends on the resin. In a study of polyethylene, HDPE, LDPE and LLDPE differed in elongation at break and impact strength at sub-zero temperatures; molecular weight, crystallinity and branching decided it. When choosing a container, ask Aris Makina for the exact material grade and the defined operating range.
Cracks start where stress gathers:
- corner joints
- hinge and latch housings
- areas that took an earlier knock
- edges of screw holes
A cold container is lowered slowly, never dragged, and nothing is stacked on it. If a crack appears, record the material code, shell temperature, load and impact point; the record separates a material limit from a handling effect. A container cracked on its inner surface should not stay in food use.
