Wet-laid nonwovens are nonwovens made by a modified
papermaking process. That is, the fibers to be used are suspended
in water uniformly at very high dilutions of 0.001 to 0.005% weight
of fibers, and then these fibers are collected onto a screen to form
a sheet after separating the fibers from the water. The wet web is
squeezed between rolls to remove most of the water and dried and bonded
further by passing it through ovens.
The most common material used in bonding wet-laid nonwovens is a water-based
emulsion or dispersion ("latex") of a crosslinkable synthetic
polymer, such as a polyacrylate, styrene-butadiene polymer, ethylene-vinyl
acetates, vinyl chlorides and so on.
The fibers in wet-laid nonwovens are laid down
in a random orientation to one another. Wet-laid nonwovens are isotropic
(equal machine and cross-directional strength), strong, highly uniform
and can be quite absorbent with excellent wicking properties.
