Hydrophilic elastically stretchable composite sheet

#This invention relates to an elastically stretchable composite sheet containing hydrophilic material.

#Japanese Patent Application Publication No. 1994-184897A and Japanese Patent Application (PCT) Publication No. 1996-504693 describe an elastically stretchable composite sheet comprising an elastic sheet having stretchability and a sheet-like fibrous assembly having inelastic stretchability bonded together. The presence of the fibrous assembly enables such a composite sheet to offer a flexible touch desired for a topsheet in a wearing article such as a disposable diaper or a sanitary napkin.

#The composite sheet of prior art advantageously eliminates a rubber touch possibly experienced by a wearer as the elastic sheet comes in contact with the wearer's skin and offers a cloth-like touch. However, the fibrous assembly constituting the composite sheet is formed, for example, with long fibers obtained through the melt spinning process or by microfibers obtained through the melt blown process. The composite sheet of prior art is disadvantageous in that these fibers are not sweat-absorbent.

#FIG. 1 is a perspective view showing a composite sheet according to this invention.

#Details of a elastically stretchable composite sheet containing hydrophilic material will be more fully understood from the description given hereunder with reference to the accompanying drawings.

#An elastically stretchable composite sheet 1 containing hydrophilic material shown by FIG. 1 in a perspective view is suitable as a liquid-pervious or liquid-impervious topsheet used for a disposable wearing article such as a disposable diaper, a sanitary napkin or a disposable gown adapted to be used in medical site. This composite sheet 1 comprises an upper layer 2 and a lower layer 3 welded together in bonding zones 4. The composite sheet 1 is elastically stretchable preferably in X- and Y-directions orthogonal to each other or at least in the Y-direction as indicated by chain lines.

#The upper layer 2 of the composite sheet 1 is inelastically stretchable preferably in the X- and Y-directions or at least in the Y-direction. This upper layer 2 is formed with an assembly of fibers 6 extending at least between a pair of the bonding zones 4, 4. Such fibers 6 may be short fibers, preferably long fibers, more preferably continuous fibers. Each of these fibers 6 extending between a pair of the bonding zones 4, 4 is longer than a straight distance between these two bonding zones 4, 4 and describes an irregular curve between these bonding zones 4, 4 over the entire upper surface of the lower layer 3. Preferably, the fibers 6 are neither welded nor bonded together, i.e., separated one from another between the bonding zones 4. The upper layer 2 is inelastically stretched and the fibers 6 respectively having described curves between respective pairs of the adjacent bonding zones 4, 4 are reoriented to extend in the Y-direction between these bonding zones 4, 4 as the composite sheet 1 is stretched in the Y-direction.