Epoxy phenol novolac resin
Epoxy novolacs carry more than two epoxide groups per molecule, building the densely crosslinked networks needed for aggressive chemical and high-temperature service.
Epoxy phenol novolac resins are made by reacting a phenol–formaldehyde novolac with epichlorohydrin, putting a glycidyl ether on many of the phenolic rings. Typical grades have an average functionality from about 2.2 to 3.6 and an EEW of roughly 172–181 g/eq. They range from viscous liquids to semi-solids.
Novolac epoxies are specified for tank linings, secondary containment, chemical-plant floors, chimney and flue-gas linings and composites exposed to strong acids, solvents and elevated temperatures. They are often blended with BPA or BPF resin to balance viscosity and toughness.
More epoxide groups per molecule mean more crosslinks per unit volume after cure, which raises Tg and chemical resistance. The trade-off is reduced flexibility and higher viscosity. Curing agents and post-cure schedules are chosen to reach the full network.
Handle like other epoxy resins, avoiding all skin contact. Warming to reduce viscosity increases vapor and burn risks, so use controlled heating.
For immersion or splash exposure to strong acids, aggressive solvents or elevated temperatures, where standard BPA epoxy linings are not rated.
They are stiffer than standard epoxies because of their dense crosslinking. Formulators balance this with flexibilizers, blends and appropriate film thickness.
