Study of an Epoxy Primer Applied to Three Layer Polyethylene Pipe Coating. Part II. Improvement of the Resistance to Hot-water Soaking

Abstract

Anti-corrosive metal-containing inorganic pigments were mixed to the non-solvent type epoxy primers for the coating application to three-layer polyethylene pipe, in order to improve the resistance to hot water soaking. Epoxy primers containing zinc or lead metal showed higher HDTs and lower water absorption than the unfilled ones. The significant improvement of the resistance to hot water soaking could be attained by the addition of these metals, different from the case of adding aluminum metal. This fact suggests that these metals form metal-amine chelating bonds in addition to the usual epoxy-amine crosslinking.