| 摘要 |
PURPOSE:To prepare a threaded product with excellent corrosion resistance, by a method wherein a surface of a metal bolt or the like is undercoated with a certain polyamideimide and, thereafter, subjected to the top coating with a heat-curable resin containing finely divided polytetrafluoroethylene. CONSTITUTION:A surface of metal threaded parts such as a bolt or a nut is coated at first with an undercoating composition containing a polyamideimide having the formula I (wherein R is a divalent aromatic hydrocarbon group and Ar is a trivalent aromatic hydrocarbon group) as a constituent unit, a solvent therefor and, according to necessity, a multifunctional compound capable of reacting therewith. After dried and, if necessary, cured by heating, a top coating composition prepared by dispersing and incorporating finely divided polytetrafluoroethylene in solution in a solvent for a heat-curable resin binder is coated in layers and, thereafter, dried and cured by heating. The threaded parts prepared by this method are excellent in corrosion resistance, weather resistance, strength, electric properties, etc. and have various uses. |
