Thermal- and solution-processable polyimides based on mellophanic dianhydride and their applications as heat-resistant adhesives for copper-clad laminates

The polymerizability and film properties of a variety of mellophanic dianhydride (MLPDA)-based polyimides (PIs) were systematically investigated for applications related to novel high-temperature adhesive materials. The MLPDA-based PIs showed Tg's comparable to or lower than those of the corresponding pyromellitic dianhydride (PMDA)-based PIs. Some of the MLPDA-based PI systems simultaneously achieved high Tg's at approximately 300 °C, excellent film toughness (an elongation at break, εb = 60-160%), high adhesion strengths with a copper foil (even at a relatively low processing temperature of 350 °C), relatively low water absorption, good thermo-oxidative stability, and excellent solution-processability.