Only thermosets can do this

Thermosets are rigid and glass-like polymer materials. At high pressure and high temperatures, the plastics are linked in a chemical reaction. As soon as the thermoset has hardened, it cannot be reshaped again. Thermosets are used for demanding requirements in terms of heat resistance, chemical resistance and electrical insulating properties.

Mouldings made of thermosets have a good dimensional stability, and they retain their electrical and dielectric properties as well as their resistance against chemicals or organic solvents, even at high operating temperatures. Hence, they comply with the required fire protection standards, even without halogenated flame retardants.