Die-cut PORON polyurethane foam is an excellent material for gasket design because it has an excellent compression set, while also working well with pressure-sensitive adhesives.
PORON can compress to more than half its thickness without losing memory, which makes it a long-lasting, effective seal in many applications. PORON polyurethane has a reputation for maintaining its compression set for the life of the product. When it comes to demanding applications, like aerospace, automotive or industrial, PORON is a highly reliable option to guard your product against leaks and other causes of the gasket failure.
Though a material like PORON has a sterling reputation for its compression set resistance, it’s critical to analyze the application to prevent gasket failure. Choosing the wrong foam density, hardness and thickness can lead to precisely that.
In the following, we’ll explain the compression set and how PORON polyurethane can help you minimize it.
Read more about SRP’s PORON custom gasket capabilities
What is compression set?
Compression set measures an elastomeric material’s ability to return to its original thickness after exposure to compression and high temperature for a specific amount of time.
Permanent set measures the extent of deformation after exposure to compression for a specific time.
Why does compression set matter?
When choosing the right material for gaskets, sealing and cushioning, factoring compression set is critical. But it’s also important to know how long the materials can stand up to squeeze. Would it need frequent replacement or will it last the life of the product?
In time, a loss of resiliency (or memory) can result in leaks or inability to absorb shock. The material’s long-term compression set resistance can be the difference between a successful product and a failed product.
When calculating compression set, you’re measuring resiliency — what percentage of thickness does it recover after compression? The range is 0% compression set to 100% compression set. The lower the percentage the higher the compression set resistance.
What causes compression set?
When the compression set of your elastomeric material is higher than expected, there may be underlying causes where the conditions exceed what the material can handle. For example:
- Temperature: Excessively high heat that leads to hardening and resiliency loss.
- Compression: Excessive squeezing (for example, over-tightening).
- Fluid: Material is incompatible with the fluids.
While considering these, consulting with an experienced fabricator of elastomeric materials can help you avoid these issues.
Why does compression set resistance matter?
Compression of the elastomeric material creates a seal protecting components from dust, dirt, moisture as well as solvents and chemicals. While most elastomeric materials can achieve a low compression rating, compression set gives you an indication of the life of the seal.
To maintain a good seal, you need a material that resists — or bounces back — from prolonged compression. However, prolonged compression can cause an elastomeric material to lose height over time. Compression creep doesn’t necessarily show up during materials testing.
PORON’s compression set resistance
PORON is a dense foam rubber made of uniform microcells with a compression set resistance that’s similar to silicone, making it a highly sought-after gasket material. These microcells allow the material to spring back to its original shape and thickness, even after a high force compression. It’s available in a range of thickness, hardness and density.
How do you choose the right PORON material?
Even though PORON is resistant to compression set, it’s still important to choose the appropriate density and hardness for your application. To guide you, PORON provides a Compression Force Deflection (CFD) Curve Tool that shows how the material performs in specific applications.
Adhesive-backed PORON solutions
SRP is proud to be one of 60 Preferred Converters for Rogers Corporation materials. Once you have your data and your selection of PORON materials narrowed, our technical experts can help you finalize your choice.
SRP is also a 3M Preferred Converter. When you’re looking for the best peel-and-stick backing for your custom die-cut PORON gasket, our unmatched technical expertise will guide you to the best choice.