These resin systems are represented within two major groups of halogen-inclusive and halogen-free systems. The halogenated FR resins are generally better performing, less expensive, easier to process and have better physical properties than halogen-free formulations. Their disadvantage lies in toxicity levels. Halogen-free FR is a type of resin that produces less toxicity and less smoke. They also are less corrosive to application equipment and, as a result, easier to handle a wider variety of tools. The main halogenated FR resins are brominated and chlorinated, whereas halogen-free FR resins contain metal hydroxides, melamine-based and phosphorous based FR’s. Halogenated epoxy vinyl esters and polyesters also exist on the market.
The type of FR resin system used will depend on the function of the polymer and the specific fire performance requirements. Many components in electrical and electronic components are also made with the use of FR polymers. Other uses can include transportation components, building panels, water treatment plant equipment, ducting, roofing and equipment exposed to high temperatures.