Coated metal pipe for vehicle piping

Abstract

Disclosed is a coated metal pipe including a metal pipe and a multi-layered coating film that covers an outer circumferential surface of the metal pipe. The multi-layered coating film includes a chemical conversion layer and a primer layer, and these layers are provided in this order from the inside. The primer layer contains polyamide imide and at least one kind of additive component selected from polyamide, a fluorine resin, a silane coupling agent, and an epoxy resin.

1 . A primer composition for vehicle piping, comprising:
 polyamide imide;   at least one kind of additive component selected from polyamide, a fluorine resin, a silane coupling agent, and an epoxy resin; and   a solvent that dissolves these, wherein   the ratio of the polyamide imide in the primer composition is 30% by mass or more, based on the mass of components other than the solvent in the primer composition, and   the ratio of the additive component in the primer composition is 30% by mass or less, based on the total mass of components other than the solvent in the primer composition.   
     
     
         2 . The primer composition for vehicle piping according to  claim 1 , wherein a ratio of a phenolic resin in the primer composition is 0% by mass or more and less than 11% by mass based on the total mass of components of the primer composition other than the solvent. 
     
     
         3 . The primer composition for vehicle piping according to  claim 1 , wherein a ratio of polyester in the primer composition is 0% by mass or more and less than 11% by mass based on the total mass of components of the primer composition other than the solvent.