| 摘要 |
<p>PURPOSE:To prevent wrinkles and shrinkage from developing at the time of solvent- welding and improve the quality of sheets by a method wherein the fluoroplastic sheets are brought into contact with ribbon-shaped heat generating bodies and energized under pressure with pulse current so as to weld together and, after that, during cooling, the sheets adhered to the heat generating bodies are peeled off and cooled under pressure again. CONSTITUTION:When pressurized ribbon-shaped heat generating bodies having the water-cooled impulse system heat source are energized with pulse current, as primary heating, the temperature of the heat generating bodies rises to a temperature, which is as high as about one-half of the melting point of fluoroplastic sheet, and, by a secondary heating, their temperature reaches the melting point of fluoroplastic. As a result, fluoroplastic sheets are solvent-welded together stably. After that, pulse current is turned OFF so as to cool the sheets under pressure, the ribbon-shaped heat generating bodies are cooled down to a temperature, which is as low as about one-half of the melting point of the material to be welded. At this stage, a press is lifted and the sheet of the materials to be solvent-welded, which has adhered to the heat generating bodies is peeled off with a sliding type peeling device and, after that, cooled down secondarily under pressure. Thus, the temperature of the heat generating bodies lowers, and the welding of the fluoroplastic sheets becomes perfect.</p> |
