| 摘要 |
<p>A method for forming a web structure having a pore size gradient which utilizes a spunbond process for producing fibers. The fibers are deposited on a contoured collection surface. Preferably, the surface is shaped as an elongated dome, having the central zone at the apex and the peripheral zones along the curved sides. The fibers are deposited onto the central zone and accumulate until they flow down the sides onto the peripheral zones. Fibers deposited onto the central zone have greater average pore size and fibers deposited onto the peripheral zone have smaller average pore size and greater fiber alignment. In an alternative embodiment, a plurality of dies in a row is used, each providing extruded fibers of distinct composition. Pore size gradient formation permits improved control of wicking and absorption over a web structure, such as a diaper or similar absorptive article. An alternative embodiment comprises providing a meltblown source of attenuated fibers, preferably co-formed with fluff.</p> |
