The Right Adhesive for the Job: Plastisol, Epoxy or Polyurethane?

Given the range of adhesive technologies used in filter assembly, it’s no surprise that filter manufacturers aren’t always sure which ones work best for what applications. This blog post focuses on clarifying the differences between three of those adhesives: polyurethanes, epoxy resins and plastisols.

Two-part polyurethanes offer great versatility and value for a number of assembly applications at the filter plant. Polyurethanes belong to the thermosetting category of adhesives, known for high bond strength and good resistance to heat and chemicals. The two-part versions cure through a chemical reaction when the components are combined and become inert once cured. Although they can be heat-accelerated, they will cure at room temperature, allowing you to bypass the need to purchase or run ovens, which can result in significant cost savings.

It’s also easy for you to find the ideal polyurethane for your specific needs. They come in a range of colours, cure rates, viscosities and hardness levels. You can use the harder formulations to assemble the filter media into a metal or plastic frame or end cap or cast as those components. Softer versions can serve as a seal between a filter and its housing, so you won’t need a separate gasket.

Like polyurethanes, epoxy resins are thermosets and become inert once cured for high temperature and chemical resistance. One-part formulation renders them easy to use. However, epoxies typically are relatively costly and often cure slowly. They often are reserved for applications that require heat resistance higher than 170 degrees or resistance to certain synthetic chemicals.

Plastisols also get points for ease of use; you don’t have to mix them, and you can pump directly from a drum. They also come in many colours and hardness levels. Although plastisols offers good chemical and heat resistance, and typically cost less up front than either polyurethanes or epoxies, they require high-temperature ovens to cure. You pay both for the energy used to heat the ovens and for a system to exhaust fumes released during the heating process.

Talk to your adhesives supplier to confirm which of these three adhesives – or of the many others used in filter manufacturing plants – is best for your specific application.