초록 ▼

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 al

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.

대표청구항 ▼

[ What is claimed is:] [1.] A method of forming a nonwoven web having a varying pore size gradient, comprising:providing a foraminous shaped forming surface that is substantially linear in a machine direction along a first horizontal axis and that includes one of a concave or convex curvature along

[ What is claimed is:] [1.] A method of forming a nonwoven web having a varying pore size gradient, comprising:providing a foraminous shaped forming surface that is substantially linear in a machine direction along a first horizontal axis and that includes one of a concave or convex curvature along a second horizontal axis that is perpendicular to said first horizontal axis;forming thermoplastic fibers;directing the thermoplastic fibers at an angle of inclination relative to said second horizontal axis against said forming surface so as to form a web thereon, said forming surface having a central zone and at least one peripheral zone, wherein said central zone has a smaller angle of inclination relative to said second horizontal axis than an angle of inclination of said at least one peripheral zone such that said fibers in said central zone have less fiber alignment than fibers in said at least one peripheral zone resulting in a larger average pore size in said central zone than a pore size in said peripheral zone.