Hydrogenated bisphenol A epoxy resin
By saturating the aromatic rings of BPA, HBPA epoxies trade some hardness for far better resistance to UV chalking.
Hydrogenated bisphenol A epoxy resin is the glycidyl ether of hydrogenated bisphenol A, in which both benzene rings are converted to cyclohexane rings. Commercial grades are low-viscosity liquids with EEWs of roughly 210–240 g/eq.
HBPA epoxies are used in weatherable epoxy topcoats, clear coatings and some outdoor composites and electrical applications where standard BPA resins would chalk and yellow.
Without aromatic rings, the resin absorbs far less UV light, so films resist chalking and discoloration much better. The saturated rings make the network less rigid than BPA epoxy and slower to cure with some amines, so hardener selection matters.
Treat as an epoxy resin: irritant and potential skin sensitizer. Avoid skin contact and use eye protection.
It is far better than standard BPA epoxy, but aliphatic polyurethanes and polyaspartics are still the usual choice for maximum gloss and color retention.
It is made from hydrogenated bisphenol A, a different, saturated molecule. Regulatory treatment can still differ by region, so check requirements for food-contact uses.
