What are the Practical Benefits of Polyurethane O-Rings?
If your application requires a material with outstanding physical durability, polyurethane o-rings are the way to go. Polyurethanes, also known as urethanes, derive their unique benefits and advantages through their unique structural bonds. These bonds are unique because of their combinations of soft polyol segments and tough isocyanate segments, creating a flexible but still durable material. There are a variety of types of polyurethane for all kinds of applications.
Types of Polyurethane
Just like all types of materials, polyurethane comes in different types, each with their own benefits and applications. The most common of these varieties is polyester with most urethane seals being based on polyester. Polyester based o-rings are resistant to hydrocarbon oils and hydraulic oils.
Two additional types of polyurethane are polyether based and polycaprolactone based rings. Polyether based o-rings have the advantages of being better for hydrolytic stability and being functional at lower temperatures. Polycaprolactone based o-rings are a subgroup of polyesters with a portion of the low temperature capabilities and oil resistances of the aforementioned polyether rings.
Curatives
Another customizable advantage of polyurethanes is the cure which is used on the o-ring, giving additional properties to the urethane. Similar to other elastomers, millable gum urethanes use the more standard peroxide and sulfur cure systems. Higher performing thermoplastics and thermosetting materials use isocyanate curing systems.
MDI is one of the most common curatives and most often used in thermoplastic materials, as well as millable gum urethanes. MDI is safer for the environment than other diisocyanates.
TODI increases heat resistance and mechanical properties. PPDI has the highest of heat resistances and is best used in applications with hot temperatures.
Properties
Polyurethanes have a wide range of properties with many different advantages and benefits. Hardness can be controlled for whatever the application requires. For applications requiring a high load bearing capacity, polyurethanes are able to return to their normal shape and form after being compressed with minimal damage. Flexibility is also a key benefit of polyurethanes with a wide range of motion and the strength to resist breakage. Durability is a key advantage of polyurethanes, being resistant to tearing and abrasion.
When insulation against various elements is a concern, polyurethanes perform. Electricity, wetness, and various temperature ranges can all be managed with different types of polyurethanes and cures. If your application requires the polyurethane ring to be bonded, that is also something this material can be designed to do, being able to adhere to wood, plastic, or metal.
If contamination of food or other sensitive material is a concern, polyurethanes are sterile against various fungi including mold and mildew.
Generally, polyurethane o-rings have cheaper tooling than plastic, making it a more cost effective option. Polyurethane o-rings are also better at resisting radiation than plastic.
When it comes to advantages of polyurethane over metal, durability is key. Rigid materials wear down faster and can’t conform as easily. Polyurethane o-ring are also quieter and don’t create sparks like metal does. Plus, they don’t rust.
Finding the Right Polyurethane O-Ring
When considering the various types of polyurethane o-rings, it’s best to consult an expert in the field. No matter the design challenges, Real Seal is up to the task. Contact Real Seal today for any questions you have regarding polyurethane o-rings.
