| 摘要 |
1,140,784. Seaming non-metallic sheet material. VEREINIGUNG VOLKSEIGENER BETRIEBE KONFEKTION. 21 June, 1967, No. 28584/67. Heading B5K. Sheets, e.g. of textile fabrics, of materials which are not high-frequency weldable are joined by sintering a high-frequency weldable thermoplastic material in powder form by dielectric heating on to the joining region of one sheet, applying the second sheet on to the sintered material and dielectrically heating and pressing together the assembled sheets to weld them together. The sintering and welding operations may be carried out in the same high frequency welding press or in separate presses. Additional heat may be supplied during welding. The powdered thermoplastic material may be a polyamide or a mixture of polyamides to which a compound having a high dielectric loss factor, e.g. titanium dioxide, has been added to improve the high frequency weldability. A plasticizer, e.g. paratoluene or suphonamide, may also be added to the thermoplastic material. Alternatively, the powdered thermoplastic material may be a polyolefine or a mixture of polymerizates thereof to which a compound with a high dielectric loss factor has been added to render it high-frequency weldable. |
