SINOMER® UVE3421 is a tetrafunctional o-cresol novolac epoxy acrylate oligomer with high acid value. It exhibits good heat resistance, excellent electrical insulation, high surface hardness, and wear resistance. It delivers outstanding adhesion on substrates such as copper, other metals, and glass. Its high acid value makes it readily soluble in alkaline solutions, classifying it as a typical alkali-developable photosensitive resin.