| 摘要 |
In the manufacture of a moisture-permeable covering film for absorbent material a thermoplastic film is provided with capillary-like protrusions by embossing, after which openings are produced in the ends of said protrusions. Embossing is effected with simultaneous cooling of the film, so that the ends of the protrusions are oriented in the thermo-elastic temperature range. By a renewed heating of the ends of the protrusions the openings are formed by shrinking, which also causes the edges of the openings to be thickened. The apparatus consists of an engraved metal cylinder and a counter-roller for the embossing step and of a heated roller, which is pressed against the ends of the embossed protrusions on the metal cylinder. |
