High Hardness Polyester Polyol Resin for Electronic Components Baking Varnishes & PCB Screen Inks SE-8661 is a special polyester polyol resin primarily used in combination with amino resins such as Desmodur 3175, Allnex 325, and 303 to prepare baking varnishes for electronic components and PCB screen-printing inks. Depending on different performance requirements, polyester polyol resins are widely used in various industrial applications including coatings and paints,