1. Technical Field of the Invention
This invention relates to nonwoven composites and particularly to nonwoven composites used in absorbent articles.
2. Description of Related Art
There are several known topsheets formed of either nonwoven materials or formed films that have been designed to handle viscous exudate such as new born infant stool or viscous menses fluid. These topsheet materials specifically have large apertures and the nonwoven products have a cloth like texture while the film products have a flat sticky surface. Formed films are typically known to have better absorbency rates and wetback properties, but nonwovens tend to be softer and gentler to the skin.
Attempts to use topsheets with large apertures has met with limited success due to the nature of the large holes. In the case of nonwovens, the large holes were two-dimensional because the soft fibers used were not sufficiently resilient to support the three dimensional structure. In the case of formed films, the material which were three dimensional and resilient enough to maintain this shape were too rigid and not soft on the wearers' skin.
Newborn infants, especially those being fed breast milk, are known to have a more fluid stool and to have explosive bowel movements due to excess gas in their sensitive systems. The combination of a fluid stool and explosive bowel movements presents a technical problem for known topsheet materials. The topsheet must have exceptionally high acquisition rates to capture the fast moving stool as it travels across the diaper. Furthermore, the topsheet must have good, wetback properties to maintain the fluid stool in the absorbent core after repeated insults.
Nonwovens and films have been designed to meet one or the other of these design criteria, yet parents still know that these explosive newborn bowel movements will likely escape all known diapers and therefore soil the infant's clothing, the parent's clothing, and bedding materials.
Similar performance criteria would be advantageous in feminine hygiene products as well.
It would be advantageous to have a topsheet with an exceptional absorbency rate while still maintaining acceptable wetback properties.