Curing Behaviour of Polycyanate Ester/o-Cresol Formaldehyde Epoxy Resin Composite System

In recent years, the application of high-density multi-layer circuit boards in electronicproducts has put forward more set of requirements, especially on the thermalstability of the insulation ink, as the key material in the manufacturing of printedcircuit board (PCB). Both o-cresol formaldehyde epoxy (OCFEP) and cyanate ester(CE) resins show outstanding thermal stability for application in PCB. In this work,cyanate prepolymer (PCE) and a PCE/OCFEP composite system were prepared. Thecuring behaviour of cyanate prepolymer/o-cresol formaldehyde epoxy resin systemwas studied with non-isothermal differential scanning calorimetry (DSC). Combinedwith the application requirement, the curing process of the system was determined as:130°C/1h+140°C/1h+180°C/1h. The DSC results also revealed that the apparentactivation energy of curing reaction was 83.22, 66.32 and 78.48 kJ/mol when PCEcontent was 80, 60 and 40 wt%, respectively. This indicates that there was an optimalproportion of PCE and OCFEP in the system. The curing kinetics followed the first orderreaction. Theoretical analysis on the curing proccess of the system with 60 wt%PCE showed that the thermal stability increased with increased post-processingtemperature. This study could provide some guides and basic data for the developmentof insulation ink for high-density multi-layer printed circuit boards.