Comparing Epoxy Resin to Polyurea Resin for Coating Applications

“I’m interested in coating drain, waste and vent piping. One of your competitors uses epoxy for coating pipe and you use polyurea. Is there really any difference when all is said and done or is most of this advertising hype?”

There are some very distinct differences between the two resins. For CIPP lateral lining applications, epoxy has been the “go-to” choice for most lateral applications in that it gives the installer a long work time before it sets off, there are no volatile organic compounds, and it wets out CIPP tubing very easily. That said, when the felt tube component of the product is removed and the epoxy is applied directly to the pipe surface there are some considerations you should consider.

Epoxy Resin

  • Epoxy, when cured, is a very brittle plastic. Without the felt tubing adding a component of flexibility, neat epoxy resin can crack when pressure is applied to the finished composite. Because of this feature of the product, delamination from the host pipe can and does occur.
  • Depending on the epoxy formulation used, heat may accelerate the delamination process and hot water or steam discharges into epoxy lined pipe may initiate failure of the product.
  • Epoxy resins tend to shrink slightly when cured and may contribute to this delamination issue.
  • Epoxy formulations tend to be more expensive than polyurea.
  • Another downside is the time factor. The application of the materials to meet a design thickness may take multiple days to complete.
  • The upside of this material is the equipment costs to apply it. Only one pump is needed to apply the product, however, delivery hoses are expendable and need to be replaced after each application of a coat of resin.

Polyurea Resin

  • The polyurea has an advantage in that it cures very quickly, which for some applications may be a downside of the product but for the rehabilitation of pipe and return it to service is a plus for this application.
  • Each coat is fully usable in DWV piping 5 minutes after the last coat is applied.
  • It is forgiving in that mistakes during the application process can be removed and replaced very easily.
  • It is much more durable than epoxy, more chemically resistant and much more flexible than epoxy which means that it is much less prone to delamination than epoxy.
  • The product expands as it cures locking itself in a “watertight” lock to the host pipe.
  • Finally, rehabilitation of piping will seal leaks and prevent future scale build-up on piping.
  • The downside of this product is that the equipment costs to apply the product are more expensive as dual pumps are needed for product delivery, although hoses are not expendable and are reused over and over again.
  • When considering material cost polyurea is about ½ the cost of epoxy considering resin and hose replacement. When labor is added in time to apply polyurea runs about 1/12th the time as applying epoxy.

For more information contact Pipe Lining Supply at +1-888-354-6464 or write info@pipeliningsupply.com.

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