US Patent 7799967 Differentially expanding absorbent structure

An absorbent structure expands to a greater extent along one surface than along an opposite surface when in the presence of a liquid. The absorbent structure may include a single layer, or two or more layers intimately bonded to one another. When in the presence of a liquid, the more expandable surface causes an increase in concavity in the X-Y plane of the structure, with the concavity being in the direction of the less expandable surface. One or both surfaces can be treated to adjust the respective level of expandability. By inducing a formed shape upon hydration swelling, a trough shape can be generated to facilitate absorbent properties, containment, and fit. The invention includes absorbent articles having such an absorbent structure incorporated therein.