| 摘要 |
PURPOSE:To eliminate a problem of corrosion of a core plate and a caulk plate by bringing the core plate into contact with the caulk plate through a specific film. CONSTITUTION:A caulk plate 6 is disposed so that it encircles a receiving part 5b of a core plate 5, and a claw part 6b is caulked on a leg portion 1a, whereby a upper tank 1 is bonded to the core plate 5. The caulking plate 6 is formed by a steel plate, a solder plated steel plate or a galvanized steel plate. The surface of the caulking plate 6 is formed with a film 8 applied with a denatured epoxy system powdery body or a denatured polyester system powdery body. The powdery material is made of a base resin material and a hardening agent. The base resin material is biphenol A system epoxy, and is classified into an epoxy system and a polyester system depending on the kind of the hardening agent. The epoxy system uses amine, dicyandiamide or isocianate as the hardening agent, while the polyester system uses isocianate or polyester as the hardening agent. |
