A process for the preparation of a photocurable composition for the screen printing

摘要

This invention relates to a method of preparing a screen printable, photocurable, solder resist coating from low molecular weight photocurable compositions comprising a polyene, a polythiol, a photocuring rate accelerator and silicone oil which comprises subjecting to actinic radiation said polyene, photocuring rate accelerator and silicone oil with up to only 20 percent of the polythiol required to react stoichiometrically with said polyene thereby increasing the viscosity of the composition and thereafter adding sufficient polythiol to the irradiated composition to react with between 50 to 100 percent of the remaining polyene to form a screen printable, photocurable, solder resist coating.