In medical packaging, sterility is non-negotiable. Whether it’s a rigid tray for surgical instruments or a barrier system for a medical device, packaging must protect the product from contamination and withstand the sterilization process without compromising clarity, integrity, or performance.
But not all resins behave the same under sterilization. For engineers, understanding how materials perform under different sterilization methods is key to making informed design decisions — and avoiding costly packaging failures.
Common Sterilization Methods in Healthcare
Ethylene Oxide (EtO):
EtO is a gas sterilization method valued for its compatibility with sensitive plastics and complex devices.
- Operates at relatively low temperatures, which minimizes material stress.
- Works with a wide variety of plastics.
- Consideration: Aeration is required to remove residual EtO gas post-sterilization.
Gamma Radiation:
Gamma uses high-energy radiation that penetrates deeply, making it a go-to for bulk sterilization.
- High-energy radiation penetrates deep into packaging and product.
- Effective for bulk sterilization.
- Challenge: Some plastics, like PET, are prone to yellowing, embrittlement, or loss of clarity after gamma exposure.
Electron Beam (E-Beam)
E-Beam delivers a concentrated dose of electrons for rapid sterilization with shorter exposure times.
- Typically less penetrating than gamma, so more suited for certain applications.
- Useful for surface and near-surface sterilization needs.
- Challenge: Can still cause color shift or brittleness in sensitive materials.
Steam (Autoclave)
Autoclave sterilization relies on high-temperature, high-pressure steam for a proven, effective process.
- Extremely effective but demanding on materials.
- Often used for metal instruments and durable plastics.
- Challenge: Only a limited set of plastics can withstand autoclave without deformation or performance loss.
How Key Materials Perform
PETG: PETG is a trusted workhorse resin, valued for its balance of clarity, toughness, and sterilization flexibility.
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Excellent clarity and toughness.
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Compatible with EtO, gamma, and e-beam sterilization.
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May show slight yellowing under higher radiation doses but maintains functional performance.
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Why it’s chosen: Reliable across the most common sterilization methods, making it a go-to for rigid medical trays.
APET: APET offers strong clarity and recyclability, but performs best in EtO sterilization settings.
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Good clarity and mechanical performance.
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Works well with EtO, but has limited radiation resistance — prone to discoloration or brittleness after gamma or e-beam exposure.
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Why it’s chosen: Cost-effective, recyclable option when EtO sterilization is the primary method.
XPP: XPP is a next-generation recyclable polypropylene designed to meet both performance and sustainability needs.
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High chemical resistance and toughness.
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Performs well under EtO, gamma, and e-beam, with strong resistance to degradation.
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Certain PP grades can withstand steam sterilization, though design validation is required.
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Why it’s chosen: Balances recyclability with broad sterilization compatibility, giving OEMs a sustainable option.
Polyethylene (PE): PE is widely used in flexible sterile barrier systems where sealability and flexibility matter most.
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Common in Tyvek®-PE laminates and pouches.
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Works with EtO and gamma, though radiation can cause oxidation and brittleness over time.
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Not typically used for rigid medical trays due to lower stiffness and heat resistance.
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Why it’s chosen: Flexible, sealable, and economical for film-based applications.
Polyvinyl Chloride (PVC): PVC has a long history in medical packaging, though sustainability concerns are shifting interest toward alternatives.
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Historically common in blister packs and device packaging.
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Compatible with EtO and gamma sterilization.
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Challenges include potential discoloration under radiation, environmental concerns around chlorine, and limited recyclability.
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Why it’s chosen: Cost-effective and formable, though environmental pressures are reducing its role.
Key Design Considerations to Avoid Failures
When designing rigid trays for sterilization, engineers should:
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Validate material compatibility early → Don’t assume one resin works across all sterilization methods.
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Account for color and clarity changes → Even slight yellowing may be unacceptable in some device categories.
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Plan for mechanical stress → Radiation and steam can reduce impact strength, leading to cracking or warping.
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Work with material suppliers → Data on sterilization performance is critical to prevent costly recalls or redesigns.
Conclusion
Choosing the right material for sterilization isn’t just about function — it’s about protecting product integrity, patient safety, and regulatory compliance.
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PETG → reliable across multiple sterilization methods.
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APET → cost-effective when EtO is the sterilization standard.
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XPP → sustainable, recyclable option with broad compatibility.
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PE → versatile for flexible barrier systems.
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PVC → still used, but facing recyclability and regulatory challenges.
At Impact Plastics, we help OEMs and converters evaluate materials against sterilization demands so medical trays perform under pressure — in every sense.
Need guidance on sterilization-compatible resins? Connect with our team to learn how PETG, APET, and XPP can be tailored to your application.