POSITIVE ACTING PHOTORESIST COMPOSITION AND IMAGEABLE ELEMENT

摘要

A positive acting, composition that can be heat-sensitive is presented, eith er coated on a lithographic base, or on a printing circuit board base, and comprises a water soluble heat-sensitive resin, a novel adhesion promoter an d a radiation absorbing agent - a dye or a pigment. An excellent film forming polymer that comprises acetal units directly pendant from the polymer polyvinyl alcohol backbone may be the only binder resin, when other resins being optional. The solubility of the coated material in the areas exposed t o near-IR laser radiation in mild alkaline developers becomes considerably higher, allowing to obtain high resolved patterns of the etch-resistant material on printing circuit boards or lithographic printing plates. The composition can be applied on the substrate from a liquid of laminated as a dry film. Sensitizers may be added to render the composition sensitive to radiation in a non-thermal sense.