Problem : Cracks with No Impact

You might have heard this feedback from a repackaging facility:

“The boxes cracked—again. No visible drop, no stacking overload. Just brittle fractures along the inner walls after the return trip with dry ice packs.”

This scenario happened during a multi-leg cold chain delivery of blood plasma, using returnable plastic containers with dry ice. The boxes appeared intact at dispatch, but developed hairline fractures at the corners and lid edges by the time they returned.

The root cause? Cryogenic stress.
Dry ice sublimates at −78.5°C, and direct exposure to such low temperatures triggered sudden contraction in incompatible plastic components.
The outcome wasn’t just surface-level cracking—it compromised structural integrity and caused slow leaks in thermal retention.

image1 Close-up of brittle cracks in plastic cold chain container after dry ice exposure

How Cryogenic Shock Breaks Plastic Boxes

❶ Not All Plastics Handle Cryogenic Conditions the Same Way

When dry ice is used as the coolant source, the temperature drop is rapid and severe. Most commodity plastics (e.g. standard PP or PE) are not designed to remain flexible under these extremes.

📌 Boxes designed for 0°C to −20°C may fail at −70°C without visible warning.

❷ Engineering Recalibration: Use Cold-Resistant PP Hollow Sheets with Buffer Structures

We've worked with OEM partners to re-engineer packaging around dry ice exposure, using modified PP hollow sheets designed for low-temperature resilience:

This redesign reduced fracture rate by 90% in closed-loop tests.

📌 Tip: Do not place dry ice blocks directly against the PP panels. Always include an insulating spacer or internal liner to buffer extreme cold.

Should You Re-Evaluate Your Cold Chain Design?

Structural cracks caused by dry ice aren’t about “bad handling.”
They happen when materials and assembly methods don’t account for cryogenic shock.

If your packaging workflow involves dry ice—especially for long-haul or return logistics—this is worth a serious reassessment.

📎 We broke down why dry ice causes invisible damage → [Next: Multi-batch Vaccine Transport and Load Balance Issues]

📎 Or return to the solution hub for cold chain packaging with PP Hollow Sheets → [Explore More Applications]
📎 Not sure if your current design can handle −78°C logistics?
Talk to our engineers at Huashuo Plastics Vietnam about proven structures using PP hollow sheets → [Contact Us]

FAQ: Cracking Problems in Dry Ice Logistics

Q1. What makes dry ice different from gel or PCM coolants?
Dry ice drops temperature below −70°C and causes material contraction stress, while PCM or gel packs rarely go below −25°C.

Q2. Can standard PP hollow sheets be used with dry ice?
No. Unless modified with cold-resistant additives, standard PP becomes brittle at sub-zero temperatures.

Q3. What’s the most effective way to prevent cracking with dry ice?
Use insulated liners or multi-layer structures to prevent direct cold transfer, and use thicker, reinforced PP sheets with elastic modifiers.

Q4. Are returnable boxes viable with dry ice logistics?
Yes—if designed correctly. Many OEMs now use modular, dry-ice-tolerant containers for loop systems.

Q5. What testing is recommended before rollout?
Conduct −80°C exposure cycling tests, focusing on corner joints, bonding seams, and lid snap fit tolerances.