| 摘要 |
Porous plates or porous foils, which are corrugated or embossed or pitted, especially separator plates for accumulators, are made from plastic powders, e.g. polystyrene or polyethylene, as follows: First flat porous plates or foils are made by sintering plastic powder by heat and, if desired, pressure. During or after sintering the plates or foils are stretched whilst at the sintering temperature. Then the sintered stretched plates are shaped by pressing with profiled tools, and cooled during or after shaping. The shaping may be effected by dies or profiled rolls. The corrugations &c. may extend parallel or at right angles to the direction of stretching. The processes may be continuous, the plastic powder being charged onto a continuously-travelling support which moves through a heating zone to sinter the powder and then through a stretching device, which may be a roller or a pair of rollers rotating with a peripheral speed greater than the speed of the travelling support. Thereafter the sheet is shaped by profiled rolls and divided into lengths. |
