| 摘要 |
PURPOSE:To obtain the metallic pipe coated with thermoplastic polyester having excellent adhesive property and adhesive strength by decompressing a section between melted thermoplastic polyester and a metallic pipe, giving electrostatic charges and extruding and coating a thermoplastic resin to the surface of the metallic pipe. CONSTITUTION:In a method in which the periphery of the metallic pipe preheated at a temperature of approximately 100-250 deg.C is coated cylindrically with thermoplastic polyester melted at approximately 260-320 deg.C by using a crosshead die or an offset die, the periphery of the metallic pipe is coated by decompressing the section between cylindrical melted thermoplastic polyester and the metallic pipe by a sucker, an evacuator, etc. while giving the metallic pipe coated electrostatic charges. The metallic pipe coated can be given electrostatic charges through a method such as a method in which the metallic pipe is grounded, negative DC high voltage is applied to a grid wire, such as a piano wire, stainless steel, etc. set up to the outer circumference of the metallic pipe coated at a proper distance, and electricity is discharged to the metallic pipe coated from the grid wire. |
