Guide to Sterilizing Thermoforming Plastics: FDA & Medical Considerations

When choosing a plastic for medical devices or food-related applications, engineers and buyers often need to balance FDA compliance with sterilization compatibility. Not all plastics can tolerate every sterilization method—and not all are cleared for food or healthcare use.

This guide summarizes how common thermoforming plastics perform under sterilization, and whether they can be sourced in FDA-compliant forms.

Understanding “FDA Approved” Plastics

 

• Food Contact: The FDA does not “approve” raw materials outright. Instead, polymers are authorized for specific food-contact uses in 21 CFR Part 177.

• Medical Devices: FDA clears or approves the final device—not the raw resin. Resin suppliers offer healthcare-grade versions (tested to ISO 10993 or USP Class VI) that support FDA submissions.

 

Quick Reference Sterilization Table

 

Sterilization Methods Explained

 

1. Steam Autoclave (121–134 °C)

• What it is: Uses pressurized saturated steam to sterilize at 121–134 °C for 15–30 minutes. It is the gold standard for reusable surgical tools, labware, and medical components because it kills bacteria, viruses, and spores effectively.

• Why it matters: High heat and moisture make it very demanding on plastics. Many soften, warp, or degrade.

• Best for: PP (polypropylene) and medical-grade PC (polycarbonate).

• Avoid: PETG, ABS, HIPS, HDPE, PVC, TPO, Kydex, Boltaron, which deform or chemically degrade under heat and moisture.

2. Gamma / Electron Beam Radiation

• What it is: Exposes products to high-energy photons (gamma rays from Cobalt-60) or high-speed electrons (e-beam). These penetrate packaging and kill microorganisms by breaking down DNA.

• Why it matters: It’s widely used for single-use medical devices, packaging, and implants. No heat is involved, so it’s good for heat-sensitive plastics.

• Good for: PETG, PC, HDPE — materials that tolerate radiation reasonably well.

• Caution: PP and ABS unless stabilized with antioxidants or radiation-resistant grades. Radiation can cause chain scission (embrittlement), discoloration, or yellowing.

3. Ethylene Oxide (EtO)

• What it is: A low-temperature gas sterilization process. EtO penetrates packaging and complex geometries, disrupting microorganisms at the cellular level. Runs at ~37–63 °C, with long aeration cycles afterward to remove residual gas.

• Why it matters: Compatible with almost all plastics because it avoids high heat and radiation. It is the most common sterilization route for flexible devices, tubing, and assemblies.

• Most versatile: Works for nearly all plastics in your list.

• Widely used: PVC tubing, PETG packaging, and ABS housings.

4. Vaporized Hydrogen Peroxide (VHP)

• What it is: Uses hydrogen peroxide in vapor form at low temperature (~30–50 °C). The vapor destroys microorganisms by oxidation. After sterilization, it breaks down into water and oxygen, leaving no residue.

• Why it matters: VHP is growing in popularity as a safer, lower-temperature alternative to EtO, with shorter turnaround times. In 2024, the FDA formally recognized it as an established sterilization method for medical devices.

• Compatible with: PP, PC, PETG, ABS — though exact compatibility is grade-dependent.

• Best suited for: Devices sensitive to heat and radiation but requiring terminal sterilization.

5. Other Approaches

• Dry Heat: Uses hot air at 160–180 °C for 1–2 hours. Too hot for most plastics listed here (good for glass and metal, not polymers).

• Chemical Disinfection: Not true sterilization, but widely used for equipment housings and enclosures. Kydex and Boltaron are specifically engineered to withstand repeated hospital cleaning with harsh chemicals like bleach, quaternary ammonium compounds, and alcohols — but they cannot withstand autoclave or radiation.

Key Takeaways for Engineers & Buyers

1. Match the plastic to the sterilization method:

   • Autoclave = PP or PC

   • Gamma = PETG, PC, HDPE

   • EtO = nearly universal fallback

   • VHP = growing FDA-recognized option

2. Don’t confuse FDA food contact with medical device use: food contact compliance ≠ healthcare grade. Always confirm the specific grade.

3. Kydex and Boltaron are “disinfect only” plastics: they resist cleaning agents but are not meant for sterilization cycles.

Final Word

Selecting the right plastic isn’t just about cost or mechanical properties. Sterilization compatibility and FDA pathway are critical for regulatory compliance and product longevity. Always confirm supplier data for the exact resin grade and validate sterilization under real-world conditions.

Need Help Choosing the Right Plastic for Your Project?
Every application has unique regulatory and sterilization requirements. If you need guidance on material selection for medical, food, or industrial parts, RapidMade’s engineering team can help you choose the best plastic and process for your needs.

Contact RapidMade today to discuss your project. You can reach a technical sales representative by clicking the contact button at the top left or using the chat feature at the bottom left of this page.