Introduction
In medical devices, gaskets are far more than sealing elements—they are critical components that ensure biocompatibility, sterility, chemical resistance, and functional reliability in some of the most demanding environments. Whether in surgical instruments, diagnostic equipment, or implantable systems, gasket performance is tied directly to patient safety and regulatory compliance. Three of the most widely used gasket materials in medical applications are silicone rubber, expanded PTFE (ePTFE), and Viton® (fluoroelastomer). Each material offers unique advantages, and proper selection depends on balancing thermal, chemical, and mechanical requirements against the strict standards of the medical industry.
Silicone Rubber Gaskets
Silicone elastomers are a mainstay in medical gasketing thanks to their unique balance of compliance, cleanliness, and thermal stability.
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Biocompatibility: Medical-grade silicone meets USP Class VI and ISO 10993 standards, making it suitable for prolonged skin or tissue contact.
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Thermal stability: Operating range from –60 °C to +200 °C supports repeated sterilization cycles, including autoclave, gamma radiation, and EtO.
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Flexibility and resilience: Maintains elasticity after compression, enabling long-term sealing in dynamic or static interfaces.
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Applications: Peristaltic pumps, respiratory devices, infusion pumps, implantable components, and surgical instruments.
Key consideration: Silicone is permeable to gases, so it is not always suitable for applications requiring absolute hermeticity.
Expanded PTFE (ePTFE) Gaskets
Expanded polytetrafluoroethylene is a microporous form of PTFE engineered into gasketing materials with high compressibility and ultra-low creep.
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Chemical resistance: Essentially inert, resisting strong acids, bases, solvents, and aggressive sterilants.
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Cleanliness: Non-particulating and compliant with FDA, and USP Class VI standards.
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Conformability: Microstructure allows excellent surface wet-out, creating seals even under low bolt load or delicate assemblies.
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Applications: Dialysis machines, pharmaceutical process equipment, fluid transfer systems, and sealing interfaces in diagnostic analyzers.
Key consideration: ePTFE is mechanically soft compared to elastomers and may require rigid compression hardware for high-pressure sealing.
Viton® (Fluoroelastomer) Gaskets
Viton®, a brand of fluoroelastomer (FKM), provides a unique balance of chemical stability and high-temperature performance.
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Chemical stability: Outstanding resistance to hydrocarbons, body fluids, and sterilants like peracetic acid and hydrogen peroxide plasma.
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Temperature range: Typically –20 °C to +200 °C, making it suitable for repeated sterilization.
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Mechanical durability: Low compression set and excellent resistance to swelling ensure reliable seals under dynamic conditions.
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Applications: Drug-delivery systems, sterilization equipment, sealing of diagnostic reagent cartridges, and surgical tools exposed to aggressive cleaning chemistries.
Key consideration: Viton is not always as biocompatible as silicone; material grade selection is crucial for direct patient-contact devices.
Material Selection Considerations
When specifying gaskets for medical devices, engineers must weigh:
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Regulatory compliance (USP Class VI, ISO 10993, FDA CFR 21)
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Sterilization compatibility (autoclave, EtO, gamma, plasma)
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Mechanical demands (dynamic vs. static sealing, compression set)
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Fluid and chemical exposure (saline, blood, disinfectants, solvents)
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Design constraints (available clamp force, micro-seal vs. macro-seal, transparency requirements in fluidic paths)
Conclusion
Silicone rubber, expanded PTFE, and Viton® each bring distinct performance attributes to medical device gasketing. Silicone offers unmatched biocompatibility and thermal resilience, ePTFE excels in chemical inertness and low-load conformability, and Viton provides superior resistance to aggressive sterilants and fluids. Properly matching material properties with application requirements is key to ensuring safe, durable, and regulatory-compliant medical devices.