| 摘要 |
An improved thermocontact welding method and apparatus for producing welded seams joining superposed thermoplastic sheets, and in particular for producing solid seams in polypropylene and other polyolefin sheets. The method includes moving a lower platen for engaging an upper die assembly for applying pressure to interposed thermoplastic sheets at areas thereof between the die surface and the platen while the die surface is at a temperature higher than the melting temperature of the sheets and while thermally isolating other areas of the sheets, and the welded sheets are coerced or ejected from the die surface during disengagement of the platen from the die assembly. A preferred product of the method is a polypropylene album leaf having pockets defined by solid weld seams for containing cards or photographs.
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