Lubrication of plastics and elastomers: choosing the right lubricant to ensure reliability

Compatibility of lubricants with plastics and elastomers : a major challenge

Lubricating plastic and elastomer components (EPDM O-rings, POM gears, PA6.6 kinematic systems, PC appearance parts, etc.) is a key step in ensuring their proper functioning and extending their service life. However, the choice of lubricant should never be left to chance: not all lubricants are compatible with all materials. Incompatibility can cause a seal to swell, plastic to crack or premature degradation of the part.

At Samaro, we work with engineers and maintenance departments to identify the most suitable lubrication solution, taking into account the nature of the materials and the application environment.

Lubrication of plastics and elastomers: what are the best practices?

Not all lubricants, whether PFAS, silicone or PAO, react in the same way when in contact with plastics or elastomers.

Some lubricants can cause the elastomer to swell or soften, reducing its sealing properties.

Others can weaken engineering plastics and cause stress cracking.

The wrong choice can also cause a loss of adhesion or lubricant migration, impairing the performance of the system.

PFAS lubricants: the benchmark for broad compatibility

PFAS lubricants are renowned for their chemical stability, resistance to extreme temperatures and very broad compatibility with most plastics and elastomers.

• Recommended flagship product: Krytox™ GPL 205
• Lubricant type: PFPE/PTFE grease
• Compatibility: ✔️ Plastics and elastomers
• Key advantages:

  • Chemically inert, does not cause swelling or cracking

  • Excellent performance at high temperatures (up to +288 °C)

  • Long-lasting lubrication, ideal for applications such as valves, taps and plastic gears.

Silicone lubricants: effective but to be used with caution

Silicone greases offer excellent lubrication and high thermal stability, but their compatibility with elastomers must be verified.

• Recommended flagship product: MOLYKOTE® 111
• Lubricant type: Silicone grease
• Compatibility: ✔️ Plastics, ❌ Elastomers
• Key advantages:

  • Resistant to water and chemicals

  • Excellent sealing and lubricating agent for plastics and metals

  • Applications: valves, static seals, pressure equipment

PAO lubricants: a high-performance, cost-effective compromise

PAO lubricants (polyalphaolefin-based oils and greases) are widely used for their good lubricating properties and compatibility with most plastics and elastomers.

• Recommended flagship product: MOLYKOTE® 4500 FMS
• Lubricant type: PAO-based synthetic grease
• Compatibility: ✔️Plastics and elastomers
• Key advantages:

  • NSF H1 certified for use in the food industry

  • Excellent resistance to oxidation and ageing

  • Ideal for plastic gears, light bearings and joints

❓FAQ – Lubrication of plastics and elastomers

🔹Why is lubricant/material compatibility so important?

The wrong choice of lubricant can damage the part (swelling, cracking, loss of elasticity) and compromise the sealing or service life of the system.

🔹Are PFAS lubricants always the best choice?

No, even though they are very stable and compatible, they can be expensive. PAOs or silicones may be more suitable depending on the application and budget.

🔹Can different types of lubricants be mixed?

It is strongly advised not to mix different types of lubricants, as this can lead to phase separation or loss of performance.

🔹How can compatibility be validated before production?

We recommend carrying out an immersion test or a trial under real conditions. Samaro can assist you in this process with the support of manufacturers.