Photochemical properties of various polyfunctional acrylates were eval
uated using UV-FTIR method. These measurements were carried out by rap
id scanning FTIR in situ with continuous UV irradiation during the cur
ing procedure. Dipentaerythritol hexaacrylate (DPET-6A) showed the hig
hest photochemical reactivity among the oligo-(acrylate)s used. Photo-
curable solder resist ink was prepared by mixing DPET-6A and resins ca
rrying acrylate or epoxide side chains besides carboxylic residues. Th
e resist films thus obtained were employed for the irradiation experim
ents. The consumptions of vinyl, epoxide, and carboxylic groups were d
etermined by FTIR spectroscopy and potentiometric titration analysis.
The comparison with the degree of photoreaction of each functional gro
up. Showed that the electric resistivity of cured film was much influe
nced by the space density of crosslinking.