Phenol formaldehyde resin
Phenol formaldehyde resins (PF), also called phenolic resins or phenoplasts, are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde. Used as the basis for Bakelite, PFs were the first commercial synthetic resins.
Source: Wikipedia — Phenol formaldehyde resin (CC BY-SA 4.0)