Photopolymerizable composition containing hydroxy acrylate or methacrylate, polyester binder and initiator

Abstract From the Canadian patent

Photopolymerizable screen printing inks comprising a hydroxyalkyl acrylate-type monomeric material a poly-, ester binder and a free-radical initiating system such, inks having a viscosity of from 5,000 to 200,000 centipoises, an acid number of from 0 to 120 and a thixotropic index of from 1 to 4. The process of using such inks to treat substrates, such as in making printed circuits which includes the steps of screen printing the photopolymerizable ink on the substrate; exposing the ink to actinic radiation to cure the ink and to form a resist; and permanently modifying the exposed areas on the substrate. The resist may thereafter be removed by dissolving in aqueous dilute alkali or an …