The development of heated piezo print heads for Ink Jet Applications has expanded the range of raw materials that can be utilized in the formulation of UV curable inks. While higher jetting temperatures increases the range of monomers and oligomers that can be successfully formulated, ink instability also increases. With increased viscosity and gel particle formation, head reliability decreases.A new range of monomers has been developed which demonstrate a remarkable increase in thermal stability. These materials are specifically designed to have low viscosity and fast cure at jetting temperatures up to 100 Deg C.Sartomer continues to expand their work in developing the line of dendrimers and specialty oligomers previously reported at NIP18 in San Diego. Polyester acrylates, based on dendrimer technology, exhibit low viscosity at room temperature, as well as improved cure speeds, essential elements of a UV ink jet formulation. Improved outdoor weatherability has become important for may ink jet applications. New urethane oligomers, with low viscosity profiles, have been developed which demonstrate excellent gloss retention and low yellowing.