Imaging Characteristics of Diazo Resin with a Dialkylamino Group for Screen Printing

Abstract

When photolysis of diazo compounds with dialkylamino groups is compared with photolysis of diazo compounds with other substituents, quantum yields Φ are larger and thermal decomposition rates are slower than for the other substituents, respectively. These properties are suitable for sensitivity and thermal stability for diazo resins. In this study, the imaging characteristics of a diazo resin with dialkylamino groups (MDR) are reported and compared with the conventional diazo resin with the phenylamino group (DPR) for screen printing. The photosensitive diazo compounds with the dialkylamino group, p-N, N bis(3-aryloxy-2-hydroxy-propyl) amino benzene diazo compound (MD), has λmax at 382 nm, and shows little absorption in the visible region. The transmittance of the diazo resin MDR based on MD in PVA film at 400 nm after exposure with a high pressure mercury lamp was 10 % higher than that of DPR which is a condensation product between p-diazodiphenylamine (DPD) and formaldehyde. Molar extinction coefficient (ε) and quantum yield (Φ) of MD at 365 nm were similar to those of p-dimethylaminobenzene diazo compounds (DED). The values of ε and Φ were 1.3 times and 1.2 times as large as those of DPD, respectively. The degradation temperature (TD) by thermogravimetric analysis of MDR was 5°C lower than that of DPR, but the storage stability of MDR was superior. We propose that the high photosensitivity, the bleaching characteristics, and the superior storage stability should make MDR a useful thick resist layer for screen printing.