Influence of Photoinitiator Sensitometric Characteristic on Light-Thermal Sensitive Microcapsule Materials

Abstract

The light-thermal sensitive microcapsule is synthesized by interfacial polymerization method. Photoinitiator sensitometric characteristic effecting on the light-thermal sensitive microcapsule is analyzed from light curing and imaging density. The curing property and imaging density of the light-thermal sensitive microcapsule are studied by FT-IR and thermal imaging technique. Results of the infrared spectra show that the free radicals induce the unsaturated-C=CH bond of encapsulated trimethylol propane triacrylate (TMPTA) crosslinking, when the microcapsules are exposed. But curing rate and degree of photopolymer TMPTA induced by photoinitiators is distinctly difference at the same exposure times. The results also show that the light curing has relations with the light absorption ability of photoinitiator and the exposure light. Thermal imaging results show that the developing density of light-thermal sensitive microcapsule gradually decreases with the exposure time prolonging, because photopolymer curing production forms the parcel role for dye precursor and decreases the combination opportunities of dye precursor and developer. The results of thermal imaging are consistent with that of the infrared spectrum. When microcapsule samples are exposed by high pressure mercury lamp light, the initiation efficiency of Irgacure 907 is more than that of Irgacure 184.