The Benefits and Limitations of Common Gasket Materials
To select the best type of gasket for any given situation, it’s important to factor in key considerations, including compressibility, sealing effectiveness, environmental exposure and key specifications. Many materials are used to effectively seal enclosures to prevent intrusion; however, polyurethane and silicone are two of the most common. Before settling on one type, learn the benefits associated with each.
Urethane (or polyurethane) is a polymer composed of organic units chained together by urethane links. Belonging to a group of polymers known as elastomers, polyurethane responds to deformation by recovering its original shape. This resiliency gives it superior load bearing properties, rebound capabilities and wear resistance, making it a good choice for many modern performance-driven applications.
Among polyurethane’s many benefits include excellent tear, abrasion and solvent resistance, along with exceptional bonding capabilities, high load-bearing capacity, strong weather resistance and very slow degradation. Polyurethane gaskets are also resistant to greases, oils, fats, moderate chemicals, hydrocarbons and Ozone. With a serviceable temperature range from -30 degrees to +175 degrees Fahrenheit, polyurethane gaskets are a poor choice for extremely high temperature environments, along with industrial environments that might expose the material to esters, ketones, concentrated acids, chlorinated and nitro hydrocarbons. Because it has a low temperature limit, polyurethane is commonly used in some of the coldest environments, since the gasket material won’t grow brittle or crack when it’s chilled or frozen.
Silicone gaskets offer high versatility which makes them an ideal choice for a wide array of applications. In addition to offering exceptional high temperature resistance, silicone boasts strong resistance to fire and weather (ozone and ultraviolet light). It also offers superior compression set resistance, allowing it to provide a strong seal for years on end.
Silicone offers very good low and high temperature capability, while maintaining superior flexibility, low toxicity, low odor and lower molding pressures. Typically used for extreme temperatures, silicone has a serviceable temperature range from -67 degrees to +400 degrees Fahrenheit. Although they boast a diverse array of qualities, silicone gaskets do have a few limitations that make them a poor choice for certain industrial applications. For instance, they generally perform poorly in applications that demand significant pressure and movement or extreme tear resistance. In addition to their poor tensile and tear strength, silicone gaskets do not respond well to oils, making them an inappropriate choice for enclosures used in some industrial environments.
Making the Right Choice
Gaskets play a critical role in protecting your enclosures from harmful intrusion. At Bison, we have years of experience and expertise that allow our experts to recommend the best gasket material for your individual needs. Contact our office to learn more.