Research On The Functional UV Inkjet Materials

In recent years, with the continuous development of inkjet technology, it was possible to apply the digital inkjet technology to the PCB manufacturing. There were two PCB manufacturing methods by inkjet technology. One was directly jetting the etch resist jet ink on the special location forming the circuit pattern, then the PCB product was manufactured by etching and striping. Another is directly jetting the conductive jet ink on the substrate forming the circuit pattern. The key of the etch resist jet ink and conductive jet ink was the synthesis of the UV curable resin, namely, low. viscosity aqueous-soluble resin and low viscosity resin.The low viscosity resin and low viscosity aqueous-soluble resin were synthesized separately. Firstly, the oligomer R1 and R2 were respectively synthesized by ethoxy modified pentaerythritol 4290 and acrylic acid or ethoxy modified dipentaerythritol R6405 and acrylic acid. The effects of catalyzer content, inhibitor content, molar ratio of acid to alcohol, solvent content and reaction temperature on the object product were investigated. The optimum synthesis conditions were determined as follows: p-Toluenesulfonic Acid 1.5%,2%, 4-Methoxyphenol 0.5%, the molar ratio of acid to alcohol 4.3,6.5, Toluene 50%, temperature 90℃. Secondly, the medium product R3 having five carbon double bonds around was synthesized by ethoxy modified dipentaerythritol R6405 and acrylic acid in the beginning. And then the aqueous-soluble resin R4 was synthesized by R3 and Maleic anhydride. The effects of catalyzer content, molar ratio of acid to alcohol and reaction time on the object product were investigated. The optimum synthesis conditions of the first step were determined as follows: p-Toluenesulfonic Acid 2% and the molar ratio of acid to alcohol 5.5. The optimum synthesis conditions of the second step were determined as follows: p-Toluenesulfonic Acid 1%, the molar ratio of acid to alcohol 1.1 and reaction time 3h.The mechanical properties and applicability were investigated by respectively testing the viscosity, UV curing time, volume shrinking ratio, flexibility, hardness and adhesion of coatings. The conductive jet ink was prepared with R1 and R2 separately as the matrix resin and silver nanoparticles as the conductive filler. And the viscosity, UV curing time, volume shrinking ratio, flexibility, hardness, adhesion of coatings and other properties were studied comparable. The electrical resistivity decreased to as low as 5×10^-6Ω·cm by using 70% silver nanoparticles and heat treatment at 200℃for less than 3min. The etch resist jet ink was prepared by R4 as the matrix resin. And the viscosity, acid number, UV curing time, volume shrinking ratio, flexibility, hardness, adhesion of coatings, etch resist and aqueous-solublility were studied.