ガラス繊維強化ポリエチレンの溶接性に関する研究(第2報)

超音波溶接について

抄録

In the previous report, an experimental study of the molding properties of fiber glass reinforced polyethylene was described. The present report explains the weldability of fiber glass reinforced polyethylene by ultrasonic welding.
Fiber glass reinforced polyethylene used for experimental study had a low density polyethylene as the matrix, random mat of glass fiber as reinforcing agent.
Ultrasonic welder used for this experiment was made by Seidenshiya-Denshi-Kogyo Co. Ltd., its frequency being 20 KHz and power 1000W. Ultrasonic welding seems to be made in the following way. Bonding surfaces of the to plastics were placed close to each other to the extent of bonding free among polymer being influencial by heat softening melt phenomena caused by ultrasonic vibration of plastics. That is to say, ultrasonic heating effect is considered to be initiated both by heat, due to internal strain caused by compressive vibration, and by crashing effect, due to heat only near the bonding surface caused by the strong stress of surface introduced by crashing between the little gap of bonding surface. We continued the experiment under the assumption that polyethlene bonding at the fiber glass reinforced polyethlene boundary surface proceed by heat from the inner parts of plastics caused by ultrasonic vibration and by heat of the surface, and that the caolscence is made in accordance with the progress of mutual diffusion of glass fiber caused by static load.
The following summary can be made from the results of the present experiment. Ultrasonic welding produced good results when glass content was small. Good weld had nearly the same strength of fiber glass reinforced polyethylene base material, by the mutual diffusion of glass fiber.