Suppliers are creating tough resins to tackle difficult jobs
From stack linings in coal-fired power plants to large tanks for chlorine bleach storage, composite applications can withstand some very harsh industrial settings. The reason these structures are so tough? Their resins.
Resilient resins are the workhorses of the composites industry. Used in industrial, transportation and building applications, resins can imbue a composite material with properties to resist corrosion caused by alkaline and acidic environments, to withstand high heat and to retard the spread of flame, smoke and toxic gases.
Corrosion and heat-resistant resins generally fall into one of these chemical classes:
- Isophthalic polyester resins
- Epoxy vinyl ester resins
- Epoxy novolac vinyl esters
- Urethane-modified vinyl ester
- Bisphenol A fumerate polyester resins
- Bisphenol epoxy vinyl ester resins
- Chlorendic polyester resins
The selection of a specific polymer for a resin formulation depends on the environment where the composite material will be used. Isophthalic polyesters, for example, are used primarily for light to moderate duty service, like piping in seawater environments. Epoxy vinyl ester resins, on the other hand, can handle moderate to heavy duty corrosives, making them a good choice for mineral and chemical processing. Epoxy novolac vinyl esters can withstand higher temperature conditions than many other resins, while bisphenol A epoxy vinyl ester offers both anti-corrosive and fire retardant properties. Flexibilized epoxy vinyl ester resins make a good anti-corrosive lining for metal tanks because they can stretch enough to accommodate the different rate at which metals and composites expand.
Resin producers offer their corrosion-resistant and heat-resistant products in different formulations. Ashland has been evolving its Derakane™ line of high-performance, thermoset epoxy vinyl ester resins for 50 years; it now has 15 different formulations designed for specific purposes and geographic areas. The variety enables fabricators to find the right epoxy for everything from chemical storage tanks, process piping, scrubbers, stacks and cooling towers to cladding, siding and roofing for buildings in corrosive and high-temperature environments.