CAUSTINERF DECIDUOUS (PEDODONTIQUE)

9003-35-4 none DTXSID2049713 Phenol formaldehyde resins(PF), also calledphenolic resinsor phenoplasts,are synthetic polymers obtained by the reaction ofphenolor substituted phenol withformaldehyde.​‍​​​​​‍​‍‍‍‍​‍‍ Used as the basis forBakelite, PFs were the first commercial synthetic resins. They have been widely used for the production of molded products includingbilliard balls, laboratory countertops, and as coatings andadhesives. They were at one time the primary material used for the production ofcircuit boardsbut have been largely replaced withepoxy resinsandfiberglasscloth, as with fire-resistantFR-4circuit board materials. There are two main production methods. The acid-catalyzed reaction of phenol and formaldehyde, with the phenol in excess quantity, forms a prepolymer known asnovolacwhich can be moulded and then cured with the addition of more formaldehyde and heat.The other method has instead the formaldehyde in excess and uses a base as catalyst, forming a prepolymer known asresole. There are many variations in both production and input materials that are used to produce a wide variety of resins for special purposes.