Absorbent structure having three-dimensional topography and method of making same

Abstract

A method of making an absorbent structure having a three-dimensional topography includes placing at least a portion of the absorbent structure between opposed mold surfaces. At least one of the mold surfaces has a three-dimensional topography. The three-dimensional topography of the mold surface is imparted onto the absorbent structure so that the absorbent structure has a three-dimensional topography corresponding to the three-dimensional topography of the mold surface.

What is claimed is: 
     
         1 . A method of making an absorbent structure having a three-dimensional topography comprises:
 passing the absorbent structure through a nip defined by opposed rolls, at least one of the rolls having a mold surface with a three-dimensional topography; and   imparting the three-dimensional topography of the mold surface onto the absorbent structure so that the absorbent structure has a three-dimensional topography corresponding to the three-dimensional topography of the mold surface, the three-dimensional topography imparted onto the absorbent structure comprising a plurality of discrete peaks surrounded by interconnected valleys.   
     
     
         2 . The method of  claim 1  wherein each of the rolls has a mold surface with a three-dimensional topography to impart a three-dimensional topography on both upper and lower surfaces of the absorbent structure. 
     
     
         3 . The method of  claim 2  wherein one of the opposed rolls comprise a first mold surface having a plurality of bumps and the other roll comprises a second mold surface having a plurality of depressions, each of the depressions in the second mold surface being suitably sized and shaped to receive a respective one of the bumps of the first mold surface. 
     
     
         4 . The method of  claim 1  wherein imparting the three-dimensional topography of the mold surface onto the absorbent structure comprises compressing the absorbent structure between the opposed rolls. 
     
     
         5 . The method of  claim 1  further comprising forming the absorbent structure from absorbent fibers and a binder material using an airlaying technique. 
     
     
         6 . The method of  claim 5  wherein the binder material is heat activatable binder material. 
     
     
         7 . The method of  claim 6  further comprising heating the absorbent structure to a temperature sufficient to activate the heat activatable binder material. 
     
     
         8 . An absorbent structure having a longitudinal axis, a lateral axis and a z-direction axis normal to the longitudinal and lateral axes, the absorbent structure comprising longitudinally opposite ends, laterally opposite side edges, an upper surface, and a lower surface, the upper surface having a three-dimensional topography relative to the longitudinal and lateral axes and defining a plurality of discrete peaks and interconnected valleys of the upper surface relative to the z-direction. 
     
     
         9 . The absorbent structure as set forth in  claim 8  wherein the lower surface has a three-dimensional topography relative to the longitudinal and lateral axes and defining a plurality of the discrete peaks and interconnected valleys of the lower surface relative to the z-direction. 
     
     
         10 . The absorbent structure as set forth in  claim 8  wherein the plurality of discrete peaks have a height in the range of about 1 mm and about 5 mm. 
     
     
         11 . The absorbent structure as set forth in  claim 8  further comprising a projected area as determined by a Topography Analysis Method, the upper surface of the absorbent structure having a vertical area as determined by the Topography Analysis Method in the range of about 0.1 cm 2  to about 0.5 cm 2  per 1.0 cm 2  projected area of the absorbent structure.