Two-ply fibrous facing material

A high loft, low density, nonwoven, fibrous two-ply facing material for an absorbent product such as a diaper which comprises a first outer layer of irregularly arranged intersecting, overlapping, mechanically interengaged, loosely assembled natural wood pulp fibers defining interstices therebetween, and a second inner layer of similarly disposed fibers in contact with said outer layer at an interface between said two layers, said inner layer including intermixed natural wood pulp fibers and thermoplastic synthetic wood pulp fibers, said synthetic wood pulp fibers having a length and denier generally similar to natural wood pulp fibers, said inner layer containing generally in the range of about 10 percent to about 30 percent by weight of synthetic wood pulp fibers and said synthetic wood pulp fibers being present at the boundary surface of said inner layer adjacent said interface in a quantity sufficient to occupy no more than about 6 percent of the area occupied by exposed fiber segments contained in said inner layer at its said boundary surface, said synthetic wood pulp fibers having a melting point lower than the melting point, or degradation temperature, of the other fibers in said two-ply facing material, fiber segments extending from either of said fibrous layers across said interface between the two layers and into the interstices between the fibers of the other layer being substantially limited to outer end portions of such fibers, said synthetic wood pulp fibers in said inner layer having been heat fused in the absence of pressure in contact with other fibers in said layer to form a fiber structure of sufficient wet strength and integrity to be self-supporting in both dry and wet condition without any additional binder, the fibers in each of said two layers being bonded with one another and with fibers in the other layer by a water soluble adhesive binder to provide sufficient mechanical integrity throughout said two-ply facing material to allow normal handling of the dry material as a whole, and to help provide, together with the already existing mechanical interengagement of whole fibers in said outer layer, sufficient mechanical integrity in said outer layer to avoid disintegration of said outer layer when the bond between said two layers is weakened by dissolving out only a portion of said water soluble binder and is then ruptured by pulling said two layers apart, so that the dry, unsoiled two-ply facing material can be subjected to normal handling without damage to the material, and after use, the facing material and any solid waste matter deposited thereon can be immersed in water for a time, swirled around in the water to dissolve out only a portion of said water soluble binder, and pulled apart into two layers as above described, to produce a self-supporting, inner fibrous layer to be discarded separately from the outer layer, and a separate assemblage of substantially all said natural wood pulp fibers that were originally in said outer layer, which assemblage of fibers together with any residue of said solid waste matter not rinsed away by said swirling action can be flushed down a waste disposal system, where after the dissolving out of said water soluble binder is completed the assemblage will disintegrate into a multiplicity of separate individual fibers or small clumps of fibers.