What are common rod seal materials (PTFE, PU, NBR)? | Insights by Polypac

1. What are the primary materials used for rod seals?

Rod seals are essential components in hydraulic and pneumatic systems, preventing fluid leakage along piston rods and maintaining system pressure. The most common materials used for rod seals include Polytetrafluoroethylene (PTFE), Polyurethane (PU), and Nitrile Butadiene Rubber (NBR). Each material offers distinct properties that influence their suitability for various applications.

2. What are the advantages and limitations of PTFE rod seals?

PTFE rod seals are renowned for their exceptional chemical resistance and ability to withstand high temperatures, making them ideal for applications involving aggressive chemicals and extreme thermal conditions. However, PTFE lacks elasticity, which can lead to challenges in sealing low-pressure static applications. Additionally, PTFE is sensitive to cold flow, potentially resulting in permanent deformation under sustained pressure over time. Installation requires precision to prevent cracking or distortion due to its rigidity. Despite these limitations, PTFE's benefits often outweigh the drawbacks in demanding environments.

3. What are the advantages and limitations of PU rod seals?

PU rod seals are favored for their excellent abrasion and extrusion resistance, high tensile strength, and tear resistance. They perform reliably in temperatures ranging from -30°C to +100°C, making them suitable for high-pressure hydraulic applications. However, PU has limited chemical resistance, being susceptible to acids, solvents, and hydrocarbons. It also has lower heat resistance compared to PTFE, which may limit its use in extremely high-temperature environments.

4. What are the advantages and limitations of NBR rod seals?

NBR rod seals are versatile and cost-effective, offering good oil, fuel, and water resistance. They are flexible and easy to install, with reliable performance in temperatures from -30°C to +100°C. NBR is compatible with most petroleum-based hydraulic fluids, making it a popular choice for general-purpose applications. However, NBR has poor resistance to ozone, weathering, and acids, and limited wear and extrusion resistance under high pressure. Its lifespan in continuous dynamic applications is shorter compared to PU and PTFE.

5. How do these materials compare in terms of performance?

When selecting a rod seal material, consider the specific requirements of your application. PTFE is ideal for environments with aggressive chemicals and high temperatures but may not be suitable for low-pressure static applications. PU offers superior abrasion and extrusion resistance, making it suitable for high-pressure hydraulic systems but has limited chemical resistance. NBR is a cost-effective option for general-purpose applications but has limitations in high-pressure and high-temperature environments. Assessing the operating conditions and performance requirements will guide the optimal material choice.

6. What are the environmental and safety considerations for these materials?

Environmental and safety considerations vary among these materials. PTFE is non-biodegradable, which can pose environmental challenges if not properly disposed of. PU is also non-biodegradable and can release harmful substances if incinerated. NBR is not biodegradable and can release toxic gases when burned. Proper disposal and recycling are important to minimize environmental impact. Additionally, all these materials are generally safe for use in industrial applications when handled and disposed of correctly.

7. How does Polypac's rod seal solutions address these considerations?

Polypac offers a range of rod seal solutions designed to meet the diverse needs of various applications. Their products are engineered to provide reliable sealing performance while considering environmental and safety factors. Polypac's commitment to quality ensures that their rod seals deliver optimal performance, durability, and compliance with industry standards, making them a trusted choice for seal manufacturing needs.

Data Sources

• Singapore Seals Pte Ltd, October 2025
• Seal Manufacturer, August 2025
• PTFE-CC, November 2024
• Eclipse Seal, October 2025
• NOK Seals, October 2025