| 摘要 |
885,820. Seaming non-metallic sheet materials. RADYNE Ltd. July 1. 1959 [April 2, 1958], No. 10626/58. Class 42 (1). [Also in Group XI] In a method of welding a sheet of thermoplastic material to a thermoplastic layer of a laminate in which a metal layer adheres to the thermoplastic layer, the laminate and the sheet are superposed and pressed together where the weld is to be made, between the metal layer of the laminate and a further electrode having highfrequency energy applied between them to heat the thermoplastic sheets dielectrically. Where two laminates of metal and plastic are to be welded together each metal layer acts as an electrode, the plastic sheets being welded together in their overlapping areas. The method may be applied to the lining of metal cans with thermoplastic material by seaming the material along the edges of the can before the ends are applied. A metal and plastic laminate is formed into a cylindrical shape with its plastic face inwards, the marginal portions of the two adjacent edges are bent and rolled together so that the plastic layer of one marginal portion comes into contact with the plastic lining of the cylinder wall adjacent the other marginal portion. A bar electrode is pressed against the interior of the cylinder wall at the site of the seam and high-frequency energy is applied between the electrode and the metal layer of the cylinder wall, the adjacent plastic layers being heated dielectrically. If desired a plastic filler string may be placed in the joint of the can. Similar plastic and metal laminated end portions may be applied to the can, the plastic layer being bonded by means of an induction heating work coil used to heat the metal wall of the can. |
