Liquid absorbent fibrous material and method of making the same

A high loft, low density, nonwoven fibrous material having good wet strength, softness, abrasion resistance and liquid absorbency and retention which comprises a plurality of irregularly arranged, intersecting, overlapping, mechanically interengaged, loosely assembled fibers including both natural wood pulp fibers and synthetic wood pulp fibers, said two types of fibers being present in different proportions in various regions positioned parallel to the median plane of the material, said regions including a first facing region containing about 20 percent by weight of synthetic wood pulp fibers and about 10 percent by weight of textile length fibers, a second absorbent reservoir region in which synthetic wood pulp fibers constitute about 10 percent by weight of the fibers, and a third capillary distribution network region in which synthetic wood pulp fibers constitute about 15 percent by weight of the fibers, the fibers in said first facing region constituting about 10 percent of the total weight of the material, and fibers in said second absorbent reservoir region constituting about 70 percent of the total weight of the fibers of the material, and the fibers in the third capillary distribution network region constituting about 20 percent of the total weight of the material, said first and third regions being located on opposite sides of said second region, the melting point of said synthetic wood pulp fibers being lower than the melting point of all other fibers in said fibrous material, segments of said synthetic wood pulp fibers being heat fused with other segments of synthetic wood pulp fibers and with segments of other fibers at a plurality of junctures throughout said fibrous material to form a self-supporting fiber structure in the absence of any additional binder, the exposed boundary surface of said first facing region being partially smoothed by light calendering throughout said surface, and the exposed boundary surface of said third capillary distribution network region comprising interengaged fibers some of which are connected with one another through hydrogen bonding, and others through heat fused junctures of synthetic wood pulp fibers with each other and also with other fibers of said region, to form a porous, paper-like layer of compacted and densified coherent fibers having high capillarity and fluid retentivity.

A method of producing a high loft, low density, nonwoven fibrous material having good wet strength, softness, abrasion resistance, and liquid absorbency and retention which comprises:

• bringing together a plurality of irregularly arranged, intersecting, overlapping, mechanically interengaged, loosely assembled fibers including both natural wood pulp fibers and synthetic wood pulp fibers to position said two types of fibers in different proportions in various regions parallel to the median plane of the material, with synthetic wood pulp fibers being positioned in a first facing region in an amount from about 6 percent to about 30 percent by weight of the fibers, in a second absorbent reservoir region in a smaller proportion than in said first region, and in a third capillary distribution network region in a proportion greater than in said second region but less than in said first region, said first and third regions being located on opposite sides of said second region, the melting point of said synthetic wood pulp fibers being lower than the melting point of all other fibers in said fibrous material;
• and
• applying heat in the absence of pressure to said plurality of fibers thus arranged to fuse and bond at least some of said synthetic wood pulp fibers with other segments of synthetic wood pulp fibers and with segments of other fibers at a plurality of junctures throughout said fibrous material to form a selfsupporting fiber structure which does not require any additional binder.

A method of producing a high loft, low density, nonwoven fibrous material having good wet strength, softness, abrasion resistance, and liquid absorbency and retention which comprises:

• bringing together a plurality of irregularly arranged, intersecting, overlapping, mechanically interengaged, loosely assembled fibers including both natural wood pulp fibers and synthetic wood pulp fibers to position said two types of fibers in different proportions in various regions parallel to the median plane of the material, the synthetic wood pulp fibers being positioned in a first facing region in an amount equal to about 20 percent by weight of the fibers, in a second absorbent reservoir region in an amount equal to about 10 percent by weight of the fibers and in a third capillary distribution network region in an amount equal to about 15 percent by weight of the fibers, the fibers thus positioned in said first facing region constituting about 10 percent of the total weight of the material, the fibers positioned in said second absorbent reservoir region constituting about 70 percent of the total weight of the fibers of the material, and the fibers positioned in the third capillary distribution network region constituting about 20 percent of the total weight of the material, said first and third regions being located on opposite sides of said second region, the melting point of said synthetic wood pulp fibers being lower than the melting point of all other fibers in said fibrous material;
• applying heat in the absence of pressure to said plurality of fibers thus arranged to fuse and bond at least some of said synthetic wood pulp fibers with other segments of synthetic wood pulp fibers and with segments of other fibers at a plurality of junctures throughout said fibrous material to form a self-supporting fiber structure which does not require any additional binder;
• lightly calendering the exposed boundary surface of said first facing region to partially smooth said surface;
• and
• applying heat and pressure to the exposed boundary surface of said third capillary distribution network region to melt synthetic wood pulp fibers and create a micro-capillary network at said boundary surface, to form a porous, paper-like layer of compacted and densified coherent fibers having high capillarity and fluid retentivity.