| 摘要 |
<p>PURPOSE:To make it possible to perform a satisfactory resistance-welding of desired position without any special device when welding, by placing a thermoplastic resin between metal plates, said resin being in the state of powder and grains of which a specified range is coated with an electric conductive film, heating and pressing to bond them. CONSTITUTION:As a method for coating resin powder and grains 4 with a film composed of electrically conductive material, the vacuum deposition with metal as evaporation source is mentioned. The ratio of the coated portion to the surface area of resin powder and grains 4 is to be in the range of 20% or above to less than 85%. If it is 85% or above, the mutual bonding of said powder and grains and also the bonding of a middle layer 3 and metal plates 2 are obstructed to be imperfect, and if it is less than 20%, the forming of a retiform circuit 5 in the middle layer 3 is imperfect. A low-temperature plasma processing under a reduced pressure is performed to the resin powder and grains prior to the coating process to increase the adhesion between said powder and grains and said metal plate. The reduced pressure may be suitably 10<-3>-10torrs. In such a manner, the retiform circuit 5 short-circuiting electrically both metal plates 2 is placed uniformly and densely in said middle layer 3 and there is neither color change nor hole appearance due to spark phenomena except in welding portions.</p> |
